Qatar Foundation Annual Research Forum Volume 2012 Issue 1
- تاريخ المؤتمر: 21-23 Oct 2012
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2012
- المنشور: ٠١ أكتوبر ٢٠١٢
401 - 450 of 469 نتائج
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An innovative approach for commercial utilization of saline-arid lands
المؤلفون: M. Ajmal KhanSoil salinity is a major impediment to crop production in many parts of the world. This necessitates search for suitable alternatives to meet the demands of burgeoning populations. Opening new lands for cultivation is not without dire ecological consequences while domestic, industrial, and agriculture utilization have increased pressure on good quality water resources. Hence, we have to live with the abundantly available saline arid lands and salty waters. In this background, logic demands that attention is to be paid to the vegetation of those habitats, which have been degraded by salinity and identify plant species growing there which may be suited to our needs. These wild plants (halophytes) could be cultivated and put to an array of usages like food, fodder, fuel wood, oilseed, medicines, chemicals, landscaping, ornamentals and environmental conservation through carbon sequestration. Halophytes have a history of being a valuable resource for utilizing saline lands and brackish water however their utilization has remained relatively unfulfilled. We have identified a number of species from the halophytic flora of the Sindh/Balochistan coast of Pakistan and adjoining inland areas that have potential for use as a feed crop for animals. Initial studies have shown that seeds of a number of halophytes can produce sufficient quantity of good quality edible oil having 70-80% unsaturated fatty acids. Ethno-botanical survey has established the presence of a number of halophytes with prospect of medicinal use for various ailments. Similarly, several species have been identified as source of biofuel/biodiesel. Species exist with potential to check shifting sand dunes and serve as a carbon sink. The above findings are of particular significance keeping in view the fact that both Pakistan and Qatar are largely arid with considerable overlapping of flora. Implication of our research conducted at University of Karachi on the sustainable development of Qatar would be discussed.
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A case study on nutritional myopathies of young camel in Qatar (Camelus dromedaries) and (Camelus bactrianus) from 0 - 3 months old of age".
المؤلفون: Luningning Mariano CruzThis study was conducted over 45 days, on a total of 25 sample animals. It targeted the nutritional myopathies of camels, born and bred in Qatar, ranging in age from zero to three months. Blood and fecal samples of young were collected to identify the quality of commercially-used starter feeds and conventional feeds. Commercially manufactured silage stored and produced within the municipality is available for herdsmen to purchase as replacement feeds for adult lactating dam. Further study will target the use of milk replacement among nursing animals due to dam with low milk output in order to prevent young animals from incurring further degenerative diseases. Randomized samples will be collected.
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DFT performance in the activation of molecular hydrogen by gold and silver
المؤلفون: Salvador Moncho Escriva, Edward N. Brothers and Benjamin G. JaneskoHeterogeneous catalysts are a critical part of industrial chemistry, primarily as a tool for more economically and ecologically efficient chemical processes. It is thus desirable to develop theoretical methods that can predict trends in catalytic activity and predict active catalyst for industrially important reactions. We have chosen to undertake a benchmarking study of various methods on the dissociation of molecular hydrogen on small gold and silver clusters. The simulation of the reactivity of H2 over small noble metal clusters is interesting both for elucidating the participation of the small clusters and also as a model for the metal-hydrogen interactions in nanoparticles and surfaces. In this study, the mechanism of the dissociation of H2 on Au3 and Ag3 clusters is computed with a high-level of theory, namely CCSD(T)/CBS. Several transition states and isomers with two independent H atoms coordinated to a triatomic cluster have been found. A benchmark study of the performance of DFT methods for the calculation of these mechanisms was perfomed. A wide range of DFT functionals have been selected for this work including a local functional; semi-local functionals; hybrid functionals; range separated hybrid functionals; double-hybrids including the HF-like exchange and MP2-like correlation; and new developed Rung 3.5 functionals including both the exact and semi-local one-particle density matrices. Wave function methods are also included for comparison purposes.
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A wind turbine for microgeneration in Qatar
المؤلفون: Abdelwahab Aroussi and Abdelbaki BenamorWind has been used as a natural renewable energy source for a few thousand years. Early applications included wind-powered ships, grain mills, water pumps, and threshing machines. With the evolution of technology, the last decades of the 20th century in particular, saw the development of machines which efficiently extract power from wind. These wind turbines are machines with rotating blades that convert the kinetic energy of wind into useful power. Qatar, like other nations, is striving to reduce its greenhouse gas emissions and as a consequence of its carbon footprint. This is despite the nation rich resources of natural gas which is deemed to be the cleanest of all fossil fuels. The need to develop a complementary renewable energy input into the grid will help diversify the energy mix of the country. The obvious renewable energy source is the sun and huge efforts and resources are being spent on optimising the technology for the hostile environment of Qatar. This paper describes the development of a small-scale wind turbine for microgeneration in the Qatari environment. The generation of electricity from wind is an improving technology with an equally increasing popularity as solar power. It is an inexhaustible resource that has no associated greenhouse gas emissions and does not use any water during the electricity generation process. Both issues are of prime concern to Qatar. The adopted strategy in the development of the microgenerator is described here. The unfavorable wind environment in Qatar is the prevalent design challenge. The wind map of Qatar is not ideal for harnessing the wind but velocities ranging from 3.6m/s to 6.3m/s are regularly registered and would produce sufficient electricity for domestic applications. The approach adopted in deciding between two or three-bladed wind turbines is driven by the trade-off between aerodynamic efficiency, complexity, cost, noise and aesthetics, which are fully explained. Additional design considerations also include wind climate, rotor type, generator type, load and noise minimisation, and control approach. The turbine is designed to complement and supplement existing electricity supply. It is physically small with minimal visual or audible impact. It requires minimum maintenance and is economically competitive.
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Lipophilic compounds in femoral gland secretions of spiny-tailed lizard, dhub, Uromastyx aegyptia microlepis (Reptilia, Agamidae) from the Qatar desert
المؤلفون: Jose Martín, Aurora Castilla, Pilar Lopez, Mohammed Al Jaidah and Raby MohtarIn many lizards, chemical compounds from the femoral gland secretions are used in intraspecific communication, but most studies describing these chemicals are for European lizard species included in the Scleroglossa clade. Lizards within the Iguanian clade have been much less studied, probably because these lizards were considered to rely more on visual cues. However, many iguanian lizards have abundant femoral secretions and are able to exercise chemosensory conspecific recognition, which might be based on compounds secreted by femoral glands. To understand what determines the composition of gland secretions of lizards and their role in social behavior, we need more studies that deal with a wider range of lizard species within different taxonomic groups and to consider a larger variety of environmental conditions. By using gas chromatography-mass spectrometry (GC-MS), we found 85 lipophilic compounds in femoral gland secretion of male and female spiny-tailed lizards, Uromastyx aegyptia microlepis. The type of compounds were similar between sexes, but males had a greater diversity of compounds (n= 80) than females (n= 64), and some specific compounds were exclusive of either males or females, and proportions differed between sexes. Main compounds were 27 steroids (58.6 % in males vs. 83.2 % in females; mainly cholesterol and 4,22-stigmastadiene-3-one), 13 carboxylic acids and some of their esters (16.5 % in males but only 1.5 % in females; mainly hexadecanoic acid), 4 terpenoids (mainly squalene; 9.5 % in males vs 3.6 % in females), 23 waxy esters of fatty acids (6.5 % in males and 6.1 % in females), α-tocopherol (3.4 % in males and 2.1 % in females), ketones (1.6 % in males and 2.0 % in females) and other minor compounds such as aldehydes (0.8 % only in males) and alcohols (0.5 % in males and 0.1 % in females). We compared these compounds with those found in other lizard species and discussed the potential signaling function of some compounds and how the xeric habitat could have conditioned the composition of secretions in order to maximize the efficiency and durability of scent marks in the desert.
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Genetic divergence among populations of the darkling beetle Adesmia cancellata in Qatar
المؤلفون: Paloma Mas-Peinado, Aurora Castilla, Mario Garcia Paris, Essam Saifelnasr and Rabi MohtarThe darkling beetle Adesmia cancellata Solier, 1835 (Coleoptera: Tenebrionidae) is considered a dominant arthropod in the Qatari desert as suggested by previous studies. The species is also distributed in the Arabian Peninsula, Syria and Israel. The objective of our study is to explore the evolutionary history of this species in Qatar through genetic analysis. We first collected different individuals of A. cancellata in the field from 12 populations distributed across Qatar between February and April 2012. We used partial sequences of the cytochrome oxidase mitochondrial marker (COI) to reveal patterns of genetic structure underlying the geographic distribution of A. cancellata in Qatar, and indirectly, to infer dispersal rates and recent and historical patterns of gene flow between populations. Phylogenetic analyses of mitochondrial sequences of this preliminary study show maximum values of 2% sequence divergence between populations. In order to explain such a low within species genetic diversity we propose the hypothesis hat the current genetic lineage of A. cancellata inhabiting Qatar entered the country quite recently, probably during the late Pleistocene. Since the time of Qatar colonization the species has spread across the country and became a dominant arthropod with respect population density and distribution area. In order to test this hypothesis it would be necessary to extend our analyses to a larger number of populations in Qatar and to compare them with populations outside Qatar throughout the world distribution range of the species.
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Benchmark study of density functional methods for organometallic reactions
المؤلفون: Rajesh Kumar Raju, Ashfaq Bengali and Edward BrothersReactions involving the formation of new metal-ligand bonds are particularly important in the energy industry as most catalytic processes involves the use of organometallic complexes as the catalyst. Using computational methods it is now possible to predict pathways and energy barriers for various catalytic reactions. We can easily predict whether a reaction is feasible or not without having to perform experiments. However, the main limitation of computational approaches is that they are highly dependent on the method that is chosen. Density functional theory (DFT) has become the preferred method for calculating a variety of molecular properties such as thermochemistry and thermochemical kinetics but, there is no universally accepted DFT functional which can be used for these types of studies. The aim of the present study is to find the best suited functional(s) for calculations involving the enthalpy of formations of organometallic complexes. We present a database of enthalpy of formation (ΔH) for 23 organometallic complexes using 26 different density functional methods and studied the accuracy of each DFT functional with respect to the experimental ΔH value. We find the most accurate functional is M06 with a mean unsigned error (MUE) of 1.9 kcal/mol, followed closely by WB97XD, M06L, PBEPBE, PW91PW91 and TPSSTPSS (MUE = 2.0, 2.0, 2.0, 2.1 and 2.3 kcal/mol respectively). The widely accepted traditional functional B3LYP shows very poor performance with a MUE value of 8.6 kcal/mol.
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Studying and comparing the erosion-enhanced pitting corrosion of X52 and X100 steels
المؤلفون: abdul rauf and Sadig MahdiThe critical ratio of Cl to HCO concerning the corrosion rate has been determined with and without electrolyte erosion in 0.3 M NaHCO3 by using various concentrations of NaCl for X52 and X100 steels. The open circuit potential (OPC) was recorded for both steels in electrolytes containing 0.3 M NaHCO3 and 0.1 M NaCl without erosion, with electrolyte erosion, and with electrolyte-silica sand erosion. Electrochemical techniques such as linear polarization resistance (LPR) and potentiodynamic polarization scans were used to study and compare the material resistance against synergistic impact of erosion and corrosion. Scanning electron microscopy (SEM) and optical microscopy were used to study the morphology of pitting corrosion in the absence and presence of erosion. The change in pitting potential due to electrolyte and electrolyte-silica sand impingement has been discussed. The microstructure and hardness of X52 and X100 steels were evaluated and discussed with respect to the erosion-corrosion behaviors. Cracks were observed at the inner wall of a pit due to silica sand impingement during erosion-enhanced pitting corrosion. X100 steel is more stable than X52 steel against pitting corrosion with and without erosion. X52 steel suffered pitting corrosion in the standstill electrolyte containing chloride whereas X100 did not, even in the presence of erosion. Pits propagate in the direction of erosion because of the impingement and disruption of the passive layer in that direction.
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First record of Meloe coelatus Reiche, 1857 (Coleoptera: Meloidae) for Qatar
المؤلفون: Mario García Paris, Jose Luis Ruiz, Aurora Castilla and Rabi MohtarBlister beetles of the genus Meloe Linnaeus, 1758, are widely distributed in temperate areas. However, their presence in arid environments is often overlooked. This is certainly true for Qatar. According to the Catalogue of Palaearctic Coleoptera (Bologna in Löbl & Smetana, 2008) there is not a single record for the genus Meloe in Qatar, although the genus is well represented in other areas of the Arabian Peninsula. Meloe coelatus is a rare species, infrequently found, distributed in a wide area of Northern Africa (from the Canary Islands to Tunisia) and in Western Asia (from Sinai Peninsula to Iran). Most of the reports correspond to isolated data; therefore, there are no records for many countries where the species might be present. We report here the discovery of a population of Meloe coelatus in northern Qatar that bridges the current geographic gap in the known distribution of the species, from Saudi Arabia to Iran. These findings suggest that the blister beetle (Coleoptera of the family Meloidae) fauna of Qatar, might be underestimated. A thorough field survey is recommended in order to document the presence of other species of this family, which was considered of medical relevance in past times.
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Solar cogeneration power desalting plant with assisted fuel
المؤلفون: Mohamed Ali Darwish and Sayeed MohammedSolar power plants using parabolic trough solar collectors, operating Rankine steam cycles, are well proven and the most widely used type of solar power plant (SPP) worldwide. These plants have a low power cycle efficiency (30%) due to low throttling conditions of 350-375°C and 100 bar. Conventional steam power plants have high throttling conditions (535-560°C and 140-160 bar) and high efficiency (38-40%). An SPP was suggested for generating electric power and desalted seawater; i.e. a cogeneration power desalting plant (CPDP) in Qatar. Qatar has large natural gas (NG) resources and Qatar's power plants use NG-fueled gas turbines. However, NG resources are finite and NG consumption is rising. As in many countries, SPPs contribute to electric power and desalted seawater production. This prolongs the life of the NG resources, and maintains an export revenue stream. This also limits the emission of greenhouse gases and air polluting gases due to NG combustion, which badly affect the environment. While NG is used in SPP to compensate the intermittent nature of solar energy, and keeps the operation during non-sunshine hours, its main purpose is to raise the SPP throttling temperature, and thus increases the steam cycle efficiency, even during full sunshine. It also lowers the cost of using expensive land where the SPP is planned. This paper studies the feasibility of utilizing NG to superheat the steam leaving the SPP solar collector field, and to heat the feed water to the collector. This drastically increases both power output and efficiency. Modifications of SPP power cycle to become a CPDP are presented.
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Study of oil/water emulsions in horizontal production pipes
The ability to predict performance of two-phase oil/water flow in pipes is essential for production operations from oil wells. Emulsions created between the flowing oil and water phases under turbulent conditions complicate the flow pattern and need to be further understood and characterized. Even when de-emulsifiers are used, turbulent emulsified flow cannot be avoided in certain sections of the pipe. The objective of this study is to enhance the ability to predict flow in production pipes for Qatar oil producing wells on the basis of a comprehensive experimental and simulation study. For the simulation study, using the actual field data, a model was built with LedaFlow© software, which can simulate the flow of oil and water in horizontal pipes. In parallel, experimental setups (batch and flowing) were built in our laboratory to study various parameters affecting emulsification using actual oil and water samples from Qatar. This intends to better understand and characterize the oil and water properties, factors affecting emulsion formation and flow conditions that govern the emulsification. This work is funded by an 11th cycle Undergraduate Research Experience Program (UREP) project [UREP 11-128-2-045] as a collaboration between Texas A&M University at Qatar (TAMU-Q) and Total Research Center-Qatar (TRC-Q). The results of the experimental work are very valuable in characterizing the conditions under which emulsions are formed, the types of emulsions created and the factors affecting it specifically for oil and water samples from Qatar wells. The work will continue in the future, to incorporate these experimental results in the simulation model and better match the field production data. The collaboration between TAMU-Q and TRC-Q was very beneficial in bringing in expertise from both institutions where academic research and industry experience and resources were combined to the benefit of the students, the researchers as well as the local industry.
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Study of the redox properties of Co3O4/SiO2 catalysts
المؤلفون: Mohamed Ali and Mahmoud KhaderBackground: Cobalt catalysts are employed in catalyzing several important and selective reactions, one of which is the Fischer-Tropsch (F-T) reaction that is becoming of particular importance because of its application in converting natural gas and coal into liquid fuels. Supported cobalt catalysts are used most commonly for F-T reactions because of their high activity, high selectivity for forming linear hydrocarbons, low activity for the water gas shift reaction and lower cost compared to noble metal catalysts. In these reactions, cobalt is supported on an silica oxide material. Objectives: To investigate the oxidation isotherms of 15 wt% Co3O4/SiO2 using the coulometric titration (CT) technique and to study the effect of the reduction gas type on the Co3O4/SiO2 isotherm. Methods: The sample to be analysed was placed in an alumina crucible that was then inserted into the centre of the YSZ tube (Fig.1). The sample was exposed to a gas mixture of H2-H2O for full reduction. Reduction also was carried out using a mixture of CO-CO2. The P(O2) was then established by equilibrium between H2 and H2O: P(O2)½ =K-1 * P(H2O)/P(H2) Oxygen was then pumped into the cell electrochemically by passing a current through the Pt electrodes (Fig. 1). The open-circuit potential across the electrodes (V) was measured in order to calculate P(O2) from the Nernst equation: V= RT/4F Ln PO2/0.21 Results: The oxidation isotherms obtained from CT for reduced 15 wt% Co3O4/SiO2 (Fig. 2) exhibit two well-defined transitions. The first transition corresponds to the oxidation of Co to CoO and the second oxidation corresponds to CoO to Co3O4. Figure 3 represents the comparison of the Co/SiO2 oxidation isotherms at 873 K due to reduction using a mixture of H2/H2O and CO/CO2. The results indicate that the isotherms exhibit the same pattern but they are different in their P(O2) values. The transitions due to CO/CO2 reduction appear at lower P(O2) values. Conclusions: Coulometric titration results show that 15 wt% Co3O4/SiO2 exhibit two well-defined steps due to Co3O4/SiO2 full reduction. This indicates that there is no strong interaction between Co and silica.
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Thermal performance prediction of a single effect air-cooled absorption air conditioner with direct expansion evaporator
المؤلفون: LikFang Sim and Saud GhaniAccording to the World Resources Institute, in the building sector, commercial buildings contributed 9.9% of greenhouse gases (GHG) and 5.6% of GHG emissions are from residential buildings. In the Gulf, the building sector is the biggest electricity consumer. During the summer months, the local dry bulb temperature can go beyond 50°C therefore it is essential to depend on mechanical ventilation systems to reduce indoor temperature. In Qatar, the majority of residential buildings still rely on conventional vapour compression cycle systems for space cooling. The major drawback of this system is the high global warming potential (GWP) refrigerant and CO2 produced to power the compressor. Absorption cooling is a technology that has been disregarded in the past due to its low coefficient of performance (COP) compared to vapour compression cycle and lack of strong policies on GHG and CO2 emission. Recently, researchers and engineers started to focus on utilising absorption chillers for space cooling due to the advantage of its low carbon emission. Research in the past has shown that absorption chillers can cut down 16.7% of CO2 emission compared to vapour compression chillers. An absorption chiller is a machine that uses heat to drive the cooling system instead of electricity as commonly known in vapour compression refrigeration systems. The major difference between the two systems is that absorption refrigeration uses a heat source to increase the pressure at the condenser instead of a mechanical compressor. This makes the absorption refrigeration system very attractive when low grade heat is available. The objective of this study is to use a numerical method to predict the rate of heat transfer and thermal performance of a small capacity (3kW) air-cooled absorption system with a direct expansion evaporator. The parameters of the study focuses on the ambient temperature ranges from 28-35°C. The concept of air-cooled absorption refrigeration systems have become more acceptable due to the exclusion of cooling towers. Although cooling towers are a key component in absorption refrigeration systems, they often consume large volumes of water due to evaporation. Another disadvantage of cooling towers is that legionella contamination often occurs when the cycle is not properly maintained.
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Passive vibration control using a linear particle chain impact damper
المؤلفون: Mohamed Gharib and Saud GhaniPassive control is preferred due to its simplicity and zero power consumption. A common passive control device is the impact damper which consists of a freely moving mass constrained by two stops inside a container mounted on the primary system. Typical application of impact dampers are vibration attenuation of cutting tools, television antennas, turbine blades, manufacturing machines, heavy armored personnel carriers (Armadillos), digger machines, structures, plates, tubing, and shafts. Researchers have attempted to develop the impact damper for many decades. The objectives have been to decrease the high accelerations, contact forces, and noise levels. The common types of impact damper are the following: single unit impact damper (1-dof or 2-dof), multi-unit impact damper, bean bag damper, particle (or granular) impact damper, resilient impact damper, and buffered impact damper. In this paper, a new type of impact damper consists of linear chain of spherical balls. Previous work proposed a new energy absorption scheme based on the multiple impact in the linear chain of spherical balls with different sizes. The new impact damper is based on placing a small ball between each two larger balls in the chain. Hence, the small ball will have numerous collisions with the larger balls during an impact event. This behavior leads to the dissipation of the kinetic energy due to the numerous collisions of the large balls. The linear chain impact damper is validated by comparing its responses with the single unit impact damper. A parametric study is conducted to specify the sufficient number of balls and the efficient diameters to be used in a specific available space in the primary system.
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Turbulent heat transfer measurements of supercritical CO₂ in a horizontal tube at relatively low Reynolds numbers
المؤلفون: Katsuyoshi Tanimizu, Shaikha Al-Suwaidi and Reza SadrSupercritical fluids have captured global attention due to their extraordinary properties, such as high heat transfer coefficients, solubility and heat storage capacity. Due to the requirement for more effective power generation systems, supercritical Brayton cycles were proposed because of its high potential for the development of high thermal efficiency power cycles with no need for condensers. It is known that small fluid temperature and pressure variations near critical point or pseudocritical regions, result in significant changes to the thermo-physical properties of the fluid. However, the available correlations for convection heat transfer do not show sufficient agreement with the available experimental data to simplify industrial design except in very limited conditions. Therefore, further experimental investigations are still required to better understand the thermal and hydraulic behaviors of the supercritical fluids before they can be widely used in industrial applications. In the newly developed test facility in Texas A&M University at Qatar, forced convection heat transfer of supercritical CO₂ in a circular horizontal tube at relatively low Reynolds numbers (Re <105) is investigated experimentally in a straight tube with an inner diameter of 8.7 mm. Experiments are carried out for different mass flow rates, fluid inlet temperatures, system pressures, and semi-local heat transfer coefficients, which are recorded at several locations in the pipe with constant heat flux. The influence of the fluid bulk temperature and pressure on the forced convection heat transfer in the tube was then recorded and compared to widely used empirical correlations. The results indicate that the effect of buoyancy on the heat transfer coefficient cannot be ignored in the near critical or pseudocritical region of fluids for this flow geometry. This dependency is believed to be due to extreme dependence of fluid properties on temperature in this region. The results suggest that the heat transfer correlation should include the buoyancy effects especially near the pseudocritical region. Therefore, new empirical correlations in horizontal pipes is proposed based on our experimental results of the heat transfer measurements. An effort is undertaken to design an inclined pipe test section for the existing facility to further study the effect of buoyancy of this flow.
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Protecting the Arabian oryx by genome sequencing
Background and Objective: The Arabian oryx (Oryx leucoryx) was hunted to near extinction in from the 1950s to the 1970s. Thus, the oryx ranks among the rarest mammals in the world. Qatar currently has ~800 oryx and has donated numerous oryx to breeding programs around the world. As such, Qatar may be a significant source of genetic diversity to the worldwide oryx population. The primary purpose of this project was to provide a genome sequence and Single Nucleotide Polymorphism (SNP) data in hopes it can be used for improving breading strategies by maintaining as much genetic diversity as possible. Methods: A DNA sample was provided from an oryx male in the Wabra Wildlife Preservation in Qatar. The animal's whole genome was sequenced using next-generation sequencing approach. After assembling the contigs, we utilized a 67bp kmer and ~2.4B paired 100bp (~80X coverage) reads from the Illumina HiSeq. These reads were distributed across libraries ranging in size from 300-1200bp for paired-end and 2000-5000bp for mate-pair libraries. Genome physical coverage by mate-pair libraries was approximately 15X. De novo gene prediction was conducted on scaffolds >500bp. SNPs were also detected. Results: Predicted genome size of ~3Gb (similar to other Mammals), a scaffold N50 of ~300kb, an assembly spanning ~2.5Gb of the genome which is likely >90% of euchromatic sequence. The sequence is distributed across 36,964 scaffolds greater than 500bp. We detected ~1M SNPs between parental alleles, which is significantly fewer than in other "rare" animals such as the giant panda. Conclusion: The initial analysis of polymorphisms suggests a relatively high level of inbreeding, and further study will be needed to clarify whether this is only in certain herds or a worldwide issue.
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Enhanced mechanical response of hybridized magnesium nano-composites as a function of strain rate
المؤلفون: Meisam Kouhi Habibi, Abdelmagid Salem Hamouda and Manoj GuptaBackground: In this work, hybrid Mg/Al-CNT nano-composites were fabricated utilizing a powder metallurgy route followed by a microwave-assisted rapid sintering technique and hot extrusion. Hybrid reinforcements (ball milled Al-CNT particles) comprising different contents of CNTs coated with fixed amounts of Al were used for strengthening. Objective: The mechanical response of hybrid Mg/Al-CNT nano-composites as a function of strain rate was investigated. Method: Tensile and compressive tests for monolithic Mg along with hybrid Mg/Al-CNT nano-composites at quasi-static and dynamic regimes were carried out using: (i) an MTS servohydraulic testing machine and (ii) a Split-Hopkinson Pressure Bar (SHPB) apparatus with an average strain rate of 10¯⁴ s¯¹ and 2×10³ s¯¹, respectively. Considering the crystallographic texture, the different mechanical responses of Mg due to the presence of hybrid Al-CNT particles as a function of strain rate under both tension and compression is differentiated here. Results: The hybrid Mg/Al-CNT nano-composites exhibited slightly smaller average matrix grain sizes compared to monolithic Mg and a reasonable hybrid Al-CNT particles distribution. The presence of hybrid Al-CNT particles weakens the basal texture and accentuates the prismatic texture (basal plane orientation parallel to ED) compared to the monolithic pure Mg which contributes to strengthening the hybrid Mg/Al-CNT nano-composite compared to monolithic Mg. It was also observed that the tremendous increase in strain rate led to a considerable increase in flow stress of monolithic Mg along with hybrid Mg/Al-CNT nano-composites under both tension and compression. Conclusions: During the tension test at both high and low strain rates, prismatic slip is the main deformation mechanism, leading to alignment of the directions with the tensile axis and to a spread of the basal plane parallel to the tensile axis. Tensile twinning is enhanced at high strain rates and remains the predominant deformation mechanism during the early stages of deformation in compression tests.
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Healthy homes: Towards a rational approach to houshold pests management in Rayyan Municipality, Qatar
المؤلفون: Hassan Farrag, Abdalla Hassan Abdalla and Megbel Madhoor Al ShamryBackground: Traditionally, household pest control relies entirely on the use of pesticides. Multiple hazards are associated with the use of pesticides. Objectives of the study: Because of the potential health effects of pesticides exposure, the main aim of this study is to seek alternative methods to control cockroaches. Management measures that keep unwanted pests out buildings and houses can control cockroaches and their associated allergens better than traditional pesticides spraying. Methods: Three methods of investigations were used: interviews with house owners, estimation of cockroach density by using sticky traps and direct observations on the habitat. Although the study was conducted mainly in Rayyan municipality but information on cockroach population density were also collected from other municipalities in Qatar. Results: Two species of cockroaches were identified. The American cockroach (Periplaneta americana L.) and the German cockroach (Blattela germanica L.). Sewage water manholes were the preferred locations for the American cockroach while the German cockroaches were found mainly in kitchens. Houses which were connected to the sewage water disposal nets suffered less from cockroach infestations. Clean houses that sanitary measures are less subjected to cockroach infestations. Regular house repairs and maintenance are negatively correlated with cockroach density. Houses with many entries suffer more from cockroaches. Number of residence in the house are positively correlated with cockroach density. Education level and awareness of the house owner is negatively correlated with the cockroach density. The use of pesticides alone achieved 54% control. Conclusion: The information collected in this study can be utilized to develop a pest management strategy taking into consideration all the components which may lead to suppress the pest population without relying exclusively on chemical use. This could be achieved through habitat manipulation, which includes maintaining proper sewer system, repairing around the house, fixing water leaks, sealing around electrical plumbing outlets, cleaning, covering garbage cans and tie garbage bags, etc. Pesticides can be used only as a spot treatment in locations where pests were located. Residents education is a major component in the control program because it will improve the awareness about the pest and how to co-operate in the control program.
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Towards integrated water management in Qatar
المؤلفون: Mohamed Ali Darwish, Basem Shomar and Mohamed Fathy HamoudaThe only available natural water resources are the extremely limited rainwater and salty groundwater. The groundwater is extremely exhausted with non-replenished rates. Its exploitation not only should be stopped, but it should be recharged to serve as strategic national water storage. The potable water demand is mainly satisfied by desalting seawater (99%), using the multi stage flash desalting system. This method is energy inefficient, very costly, and should be replaced with a more energy efficient desalting system such as the seawater reverse osmosis system. This can save up to three-fourths of the fuel energy used for desalination and substantially reduce the desalting water cost. Treated wastewater is another resource that should be utilized. Its cost is much cheaper than desalting seawater. Its amount increases with increasing population and consumption. Water consumption/capita is extremely high, and should be reduced through effective demand management. Qatar freshwater production can satisfy twice the demand when used wisely. The Qatari water problem resulted from; limited natural water resources, over exploitation of limited replenished groundwater, causing their depletion, full dependence on desalted seawater for municipal uses, and high energy consuming desalting system; and thus leading to high desalted seawater cost, combining desalting units with power plants of limited water to power ratio, inability to satisfy the high water demand increase compared to power demand, vulnerability of desalting seawater systems, incomplete utilization of reclaimed treated wastewater, lack of public incentives measures to conserve water, unrealistic low pricing of water and power, and lack of awareness of the value of water in homes and public buildings. Solving water problems in Qatar needs a suitable integrated water management plan (IWMP) for the unique nature of Qatar. The main objectives of the IWMP are the managing of both water resources and demand. This paper is looking for the factors affecting the adoption of an integrated water management plan to solve the water problem.
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The antimicrobial properties of Arab desert plants
المؤلفون: Jennifer Strickland and Susan MadziaBackground and Objectives: Due to overuse and inappropriate use of antibiotics, many pathogens are now highly resistant to common antibiotics. This has caused difficulties in controlling disease, particularly in developing countries, where infectious, enteric and diarrheal diseases are a leading cause of illness and mortality. The purpose of this study was to determine the antimicrobial activity of Qatar's local desert plants in an effort to find potential new sources of antimicrobial agents that may be effective in the fight against existing and emerging infections. Methods: Nineteen desert plants were collected in the winter of 2011. Their parts were separated into flower, leaf, stem and root, and, in one plant, seeds. Each plant part was extracted with water, hexane and methane. The plant extracts were tested for their antimicrobial activity against 10 Gram-positive and Gram-negative common human pathogenic bacteria as well as a fungus--Candida albicans. The Kirby-Bauer disk diffusion method was used for testing, and the resulting zone of inhibition, which indicates antimicrobial activity, was measured and recorded. Results: All nineteen plants included in this study demonstrated some antimicrobial activity in one of the four plant parts. Paronychia argyrocoma showed the strongest activity, inhibiting growth in both Gram-negative and Gram-positive microorganisms in all extracts. Salvia aegyptiaca, Pulicaria undulata, Althea ludwigii, and Vicoa pentanema also exhibited positive results in all extracts in many of the plant sections. Conclusions: This study indicates that many of the desert plants tested are an important source of antimicrobial compounds. Several plants showed remarkable antimicrobial effects against a wide variety of Gram-positive and Gram-negative pathogens. This study supports the use of these local plants in traditional medicine and may provide sustainable and new sources of antimicrobial agents. Further studies are needed on the most active plants to explore the development of new antimicrobial drugs.
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Effects of mineralogy on wormhole propagation in carbonate acidizing
Matrix acidizing is a common stimulation method for wells in carbonate reservoirs. Typically, 15% HCl in water, and some additives for specific purposes, is injected into carbonate rocks to create wormholes to improve hydrocarbon flow. These wormholes are formed by acid dissolution of the carbonate rock. The path by which the wormholes are formed is normally of lowest resistance. The path of rock dissolution is governed by permeability heterogeneity and normally follows the path of highest permeability. There are other aspects that could influence the path of the wormhole, that is mineralogy heterogeneity. When an acid is exposed to an insoluble mineral, it is expected that it will change its path and could deviate, even from the path of highest permeability. Effects of this process on the stimulation treatment are expected to vary from one rock type to another. The objective of this study was to compare the path of the wormhole in rocks with homogenous mineralogy with that of rocks with heterogeneous mineralogy. In both cases, the permeability distribution in the rock was analyzed and compared to the path of the wormhole. The ultimate goal was to define whether the presence of acid insoluble minerals affects the path of the wormhole. Micro-CT scanning at various resolutions was utilized to visualize the pore space connectivity. Thin section analysis of rock samples was used, in combination with micro-CT images, to identify mineralogy at various locations. This was conducted with the support of scanning electron microscope (SEM) analysis. Thin section analysis was conducted for the same rock samples that were scanned and the results were compared so that CT-images can be calibrated and used to identify mineralogy of other similar rock samples. The results were beneficial to the research team as more information about the rock properties from CT-scan images were obtained.
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Progress on fine-mapping the gender control gene in date palm
المؤلفون: Lisa Sara Mathew, Yasmin Mohamoud, Eman Al-Dous, Yasmeen Salameh, Eman Al-Azwani, Binu George and Joel MalekIntroduction and Background: The date palm is a critical tree to Arabian Gulf agriculture, history and culture. Dates are a major source of nutrition in the region, and the tree itself plays an important role in the development of sustainable agriculture in many drought and saline-affected regions of the world. Date palm development presents a challenge, however, as the tree is a dioecious species, that is, individual plants are either male or female and are indistinguishable during the first 5-8 years, until flowering begins. We recently identified a region of the date palm genome linked to gender, which showed that the date palm employs an XY system of gender inheritance similar to that of humans. Methods and Technology: As part of a development plan we recently released a draft sequence of the date palm genome (Khalas female). In our findings, we identified sequence variations on four contigs that were strongly linked to gender and validated them in a large pedigree. We identified an additional 20 contigs with some evidence of linkage to gender. Validation of new gender-linked contigs will help in the fine-mapping of a possible single mutation, which results in gender determination in date palm. To validate linkage we have amplified the DNA of 7 male and 7 female date palm samples using 20 specifically designed primers. The PCR products obtained are sequenced by Sanger's sequencing. The sequenced regions from these contigs are from a diverse set of male and female date palms. We are studying these sequences and regions to identify a possible specific mutation or other gene content difference that determines plant gender. Result: We have confirmed linkage in many of the contigs, and these provide a set of genes within the "degraded" male sequence which may offer clues to how gender is determined biochemically and developmentally in date palm. Conclusion: There may be many more additional contigs which we are investigating to aid in the mapping of more variations and mutations, which correspond to different traits and features in the date palm, particularly dealing with gender.
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Smart metering project: Benefits and lessons
المؤلفون: Mohamed HAOUCHE, Simon MANSON, Younes DEFFOUS and Jean-Francois AUTHIERTotal E&P Qatar (TEPQ) have made a significant effort to test new approaches to improve its current production metering systems for multiphase flow conditions. New technologies are tested through pilot applications on field. One of which is the use of advanced data validation and reconciliation (DVR) in oil and gas production activities. The goal is to reconcile in real-time the measured data and estimate all new information from a plant, which are not continuously measured. In this case, the target is the three phase flow rates: oil, water and gas. The study intends to provide a summary of the achievements, benefits and lessons learned from the application of DVR pilot on multiphase flow metering in Total's field in Qatar. This field is operated by Total under a production sharing agreement with Qatar Petroleum. Theoretically, the DVR approach uses information redundancy to correct data and re-evaluate its accuracy. Direct measurements and model parameters are processed at the same time. The input data consists of pressure volume temperature measurements (fluid) and electrical power consumption (motor current, voltage & frequency). We have derived models to estimate the flow rates of the three phases on the basis of these input data. Simultaneously, thanks to the reconciliation process, the input data are corrected with respect to material and energy balances. The output results constitute a set of reconciled data and calculated information with high accuracy. The DVR pilot is currently in the process of finalization to become an operational tool. Online acquisition and processing is performed and daily reporting is shared among operational engineering teams. It was found that the major challenge was related to the modelling of production equipments. A significantly longer period of time was allocated to better understand their actual behaviour in real environments. In conclusion, this pilot study of new approaches has allowed us to enhance the reliability of our metering system and increase our efficiency for installation assessments. Moreover, these findings will allow researchers to conduct further studies with more operational challenges. Further conclusions will be presented in this paper.
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Metal oxides and their heterointerfaces modelled with screened hybrid density functional theory
المؤلفون: Fadwa El-Mellouhi, Edward N Brothers, Melissa J Lucero and Gustavo E ScuseriaHeterointerfaces between metal oxides show substantial promise as components for future materials in energy application. Heterointerfaces exhibit unique properties that do not exist in the corresponding bulk parent compounds. In their bulk phase, SrTiO3 and LaAlO3 are non-magnetic wide bandgap insulators, but when they are assembled to make superlattices (LaAlO3/SrTiO3) they exhibit very interesting properties like high Tc superconductivity, magnetism, ferroelectricity and colossal magnetoresistance. This behavior can be explained and enhanced through theoretical investigation such as electronic structure calculations. Electronic structure calculations on bulk metal oxides using screened hybrid functionals gained a lot of popularity in the last few years due to their high accuracy and computational efficiency. In this work, we use the most effective screened hybrid functional derived from our previous studies to compute the structural and electronic properties of bulk SrTiO3, LaAlO3 and LATiO3 and the LaAlO3/SrTiO3 superlattices. We will show how our calculations have performed exceptionally well, allowing us to assess how phase transition defects and doping affect the electronic properties of these materials.
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Separation, pre-concentration and determination of stroniutm-90 in environmental soil samples by inductively coupled plasma mass spectrometry
المؤلفون: Saeed H. Al-Meer, Mohamed A. Amr, Saoud K. Al-Shammari and Dalia M. EwisIntroduction: Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of many radioisotopes including 99Tc, 226Ra, 235,236,238U, 232Th, and 239,240Pu. The major challenge in the determination of 90Sr is the separation of isobaric and polyatomic interferences. 90Sr is found in the environment at specific activities ranging from a few millibecquerels to several becquerels, depending on the medium studied. These specific activities, converted to masses, represent only a few femtograms and are significantly lower than the typical detection limits of most ICP-MSs using direct aspiration nebulization. This suggests that a pre-concentration of the 90Sr is necessary in order to increase the number of atoms detected. Objectives: The objective of this study was to develop a method for the ultratrace determination of 90Sr in environmental soil samples using ICP-MS. Methodology: Strontium was separated from matrix using a selective extraction chromatographic Sr-resin (100-150 m) from EiChrom. The resin was conditioned with 10 mL of 8 M HNO3. The samples were loaded and the resin was rinsed with 3 mL of 3 M HNO3. Zirconium and other matrix elements were washed from the column to leave pure Sr on the column. Strontium was eluted with 10 mL of distilled water. The final solution was analyzed by ICP-MS. Results: Following the acid digestion, extraction chromatography was tested to assess their usefulness in reducing its interferences. A 90Sr pre-concentration of >300-fold and recoveries of 60-70% were obtained using a combined extraction chromatography and pre-concentration by evaporation protocol. Improvement in sensitivity of 90Sr was found by optimization of the ICP-MS parameters using the stable isotope 88Sr. The detection limit was improved by a factor of 300 for 90Sr. A detection limit of 0.2 ppt was obtained. The method was applied to determine 90Sr in the environmental soil samples. The average 90Sr/86Sr isotope ratio was 4.05×10−9. Conclusions: The main 90Sr/86Sr isotope ratio in environmental soil samples confirms that the source of 90Sr is the global fallout. The overall time requirement for the measurement of 90Sr by ICP-MS is 2 days, significantly shorter than any radioanalytical protocol currently available.
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Investigation into the impact of gas-to-liquid fuel components on elastomeric sealing materials in a gas turbine engine
المؤلفون: Yue Liu and Christopher WilsonBackground & Objectives With the aim to become the Gas-to-Liquid (GTL) capital of the world, Qatar has put great effort into the research of adopting GTL fuel to replace conventional petroleum-derived fuel in current aircraft engines. One of the crucial aspects is the elastomer compatibility issue, as it is believed that GTL fuel may cause seals to shrink or no longer provide an effective sealing due to the lack of aromatics. The purpose of this project, funded by Qatar Science and Technology Park (QSTP), is to investigate the effects of GTL fuel components on O-rings made from various materials. Methods Stress relaxation test is employed for the purpose using the Elastocon Relaxation Tester. Three O-ring materials were tested, namely nitrile, fluorosilicone, and fluorocarbon. N-decane and ShellSol T solvent were chosen to represent normal and iso-paraffins respectively, as they are the main components of GTL fuel. Decalin, a cycloparaffin is included to form a triangle with the other two as previous research indicated cycloparaffin may have the potential to promote seal swelling. 25 blends were prepared with various proportions of the three solvents. Results The results indicated that both fluorosilicone and fluorocarbon O-rings showed excellent compatibility with all 25 blends tested. The stress relaxation characteristic of nitrile O-ring was highly dependent on the composition of the solvents; the more decalin (n-decane) is in the blend, the better (worse) its sealing performance becomes. Effects of the three solvents presented in the tests indicated aromatics are not the only compounds that can swell nitrile O-ring. N-decane also showed certain O-ring swelling ability but its main effect during the polymer-fuel interaction process is to extract materials out of nitrile O-ring. Iso-paraffins do not participate in the O-ring swelling process but only extract polymer materials; however its extraction ability is relatively weaker than n-decane. Conclusions Fluorosilicone and fluorocarbon O-rings are fully compatible with GTL fuel, while nitrile material may shrink when exposed to it. Decalin is capable to swell nitrile O-ring; however, the proportion of decalin in the solvent has to be no less than 60% to be comparable to Jet A-1.
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Biodegradation polycyclic aromatic hydrocarbons (PAHs) in the soil of Arabian Gulf region of Saudi Arabia
المؤلفون: Kawther Elsayed Fahmi Elshinawi and shaza MouradThe environmental fate of the polycyclic aromatic hydrocarbons (PAHs) is prompted by their ubiquitous distribution and their potentially deleterious effect on human health by their carcinogenic and mutagenic effects. PAHs are the most important components retained in the soil environment after an oil spill. Biodegradation of PAHs by microorganisms is the subject of many reviews, but every habitat had its own personality. Our study was selected by satellite images for Marduma Bay, located in the north-west of Jubal industry city, which lies on the coast of the Arabian Gulf of Saudi Arabia and is described as a heavy polluted region. Its polluted rate was identified between (8 to 10% w/w.) Chenopodium sp. is a naturally dominant plant that tolerates both salinity and pollution. Three soil samples were collected. The first one is the rhizosphere sample (R 4) in addition to two soil samples; one of polluted area (S5) & non-polluted one (S0). The rhizosphere sample showed the maximum bacterial count for both total heterotrophic bacteria, which was (98.2 to 94.2+0.1 CFUx106/g); and maximum count for oil degrading bacteria, which was (55.3 to 45.1+0.01 CFUx106/g). The concentrations of oil-degraders in different habitats were recorded on mineral media supplement with 2% crude oil as the only carbon source, thus recording a positive effect of the rhizosphere and phytoremediation process. As for the results of oil degrading microorganisms, soil samples of polluted regions (S5) and non- polluted soil (S0) indicated concentrations of (93.5 to 82.2+0,01 CFUx104/g) and (11.9 to 12.2+0.02 CFUx 104/g) respectively, and thus recording adaptation of this group of organisms in polluted habitat. The biodegradation of 16 PAHs individuals in both the rhizosphere (R4) sample of Chenopodiaceae and non-rhizosphere (S5) sample during 180 days was (77.4%) for the rhizosphere and (52.2%) for the non-rhizosphere. The residual of total carcinogenic PAHs with four rings structures recorded a loss between (55.7 to 75.4%) and (24.3 to 46.1%) for the five rig structure. Also, the residual of total carcinogenic PAHs was (49.1%) for the rhizoshpere and (31.7%) for the non-rhizosphere.
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Assessing the impact of atmospheric aerosols and clouds on solar power generation systems in Qatar and the Middle East
المؤلفون: Maudood Khan, Mohammed Ayoub, Yasir Elginaid Mohieldeen, Arastoo Biazar and Michael NewchurchBackground & Objectives: Renewable energy generation systems are highly sensitive to climate. For example, clouds have a significant influence on solar power generation systems. They in turn are impacted by atmospheric aerosols which act as cloud condensation nuclei. Aerosols are both directly emitted from anthropogenic (e.g., power plants, transportation systems, industrial facilities) and natural sources (e.g., windblown dust, sea salt, forest fires), and form in the atmosphere. They can either inhibit or promote cloud formation, and/or precipitation, and thus are likely to play a significant role in altering the hydrological cycle, and perhaps electricity generation from hydroelectric, solar, and wind power systems. Integration of renewable energy systems within existing power generation infrastructure systems remains a challenging task as well. The objective of this study is to use cutting-edge satellite imaging technology and observations and coupled models to identify atmospheric variables and processes that impact solar power generation systems in Qatar and the Middle East. Methods: We will employ data from the Aerosol Robotic Network (AERONET) in situ measurements, Moderate Resolution Imaging Spectroradiometer (MODIS) satellite, and the Clouds and the Earth's Radiant Energy System (CERES) scanner. We will also assess the potential impact of future changes in atmospheric composition, clouds, and radiation on solar power generation systems. For this purpose, we will employ version 5.0 of the Community Multiscale Air Quality (CMAQ) modeling system, and the Weather Research and Forecasting (WRF) model. Results: The research will provide a set of model and satellite-based maps showing the spatial and temporal distribution of aerosols over the region, potentially assisting analysis aimed at identifying sites for solar power generation systems in Qatar. Conclusions: The research project will help establish the knowledge infrastructure that relies on computational science and space technology to ensure that Qatar continues on the path of economic prosperity through effective integration of emerging technologies with existing infrastructure.
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A computational model for predicting the fluid motion induced by Brownian motions of suspended nanoparticles
المؤلفون: Way Lee Cheng, Anoop Kanjirakat and Reza SadrNanoparticles, when suspended in a base liquid have been reported to enhance heat transfer properties. This suggests a potential in industrial applications. However, the extent of reported enhancements were inconsistent. The underlying principal that leads to the improvements is not clearly understood, albeit the interactions between the particles and fluid which is likely to be the main contributor to the observed phenomena. Further research efforts are needed in this area as the previously proposed theories were inconclusive or even contradicting. In this study, a novel approach of using computational analytical code is being developed for studying the velocity field in the base fluid induced by the suspended nanoparticles. The Langevin equation was used to evaluate the randomly moving nanoparticles with unconfined Brownian motions. The induced velocity field in the vicinity fluid is determined by solving the governing hydrodynamic equations, assuming no interaction between particles. The criterion of various numerical parameters such as time step size, computational domain definition will be discussed. To reduce the computational cost, the motion of a sample of Brownian particles is traced upon and recorded throughout the calculation, for which a statistical representation of the induced fluid field can then be obtained. The effects of various parameters on the induced fluid field will also be examined and discussed.
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Development and characterization of high strength steel for down hole application in sour environments with superior corrosion and wear resistance
المؤلفون: Walid Khalfaoui, Bruce Palmer and Brajendra MichraBackground and Objectives: The down hole application environment is highly corrosive due to the presence of hydrogen sulfide and carbon dioxide in brines. To handle this environment, special materials with a high resistance to pitting corrosion and a high capability of repassivation are used such as steels containing molybdenum, chromium and nickel. The cost of the metallic constituents in these alloys can preclude their use in some applications. The objective of this study is to provide cheaper materials withstanding these conditions. The materials developed in this study are high interstitial stainless steels (HISS) with high nitrogen and carbon content. Methods: Several studies showed that the addition of nitrogen and carbon in stainless steels enhance their pitting corrosion resistance, increase their critical pitting temperature and also increase their repassivation rates. In order to develop high nitrogen and carbon content stainless steels we employed the air-casting techniques developed by the Colorado School Mines. In these techniques, the nitrogen is added to the melt using nitrogen-bearing additives (nitrided manganese). In this case, the nitrided manganese is placed in cavities in the mold, and melts when the liquid metal enters the mold. In order to characterize the chemical and mechanical properties of the HISS several tests were performed. The XRF and the EDX techniques were used to determine the chemical composition. The microstructure was observed using an inverted optical microscope and a scanning electron microscope. The corrosion resistance to 3.5% sodium chloride solution was studied using weight loss and electrochemical tests. The corrosion tests under sour environment will be performed as soon as the sour gas research laboratory will be constructed. The hardness of the HISS was measured using the Rockwell hardness test. Results: Preliminary investigations show that the microstructure of the developed materials contain nitrites and carbides which have a bad effect on the pitting corrosion. This problem can be solved by applying the adequate heat treatments. These results also show that the developed stainless steels are harder than nickel-molybdenum.
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A framework for upstream natural gas supply chain design: LNG distribution network
المؤلفون: Fatih Mutlu, Ali Riza Guner, Hakan Yildiz, Ramamoorthi Ravi and Shaligram PokharelNatural gas is distributed in the form of liquefied natural gas (LNG) when transported across long distances. Delivery planning of LNG offers challenging multi-origin vehicle routing problems, with vessels of various capacities and fuel performance. There are also unique challenges due to the nature of LNG trading and shipping. We propose a framework design for this planning problem by considering the multiple objectives and unique characteristics of the problem to develop efficient solutions. We aim to study the planning problems at various levels by using mixed-integer programming solution techniques, heuristics, and meta-heuristics. A critical analysis of the existing literature for similar problems was conducted and the formulations for the LNG delivery problems of Qatar are presented. The LNG inventory and routing problems are fairly complicated problems due to their unique features. The formulations developed are an attempt at solving the large LNG distribution challenges in the case of Qatargas and Rasgas in Qatar.
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Fire safety evaluation of photovoltaic modules in an explosive atmosphere
المؤلفون: Anbu Vendan D.Pandian, B.S.S. Daniel, Kamal Bansal and Pooja AgarwalaBackground: Application of photovoltaic (PV) modules as a source of electrical power in an explosive atmosphere needs thorough evaluation in fire hazard perspectives. Surface temperature above 85°C can become a source of ignition in an explosive atmosphere in a hydrocarbon industry. PV modules fire safety aspects are well defined with classifications based on voltage levels and access by human etc., through the IEC 61730, ANSI/UL 790 standards. However, evaluation of safety based on application specifics is not covered in design standards. Hot spot heating phenomena occurring in PV modules, caused by faulty conditions such as partial shading, material imperfection, fabrication flaws, damages etc., are the result of reverse biasing of cells which can lead to a localized p-n junction breakdown. Hot spots due to partial shading or illumination distribution imbalances causes localized heating wherein the temperature can rise in the range of ~150-200°C. Also, the intensity of the temperature rise can reach up to 300°C when hot spots occur due to a crack or damage of a cell. Autoignition temperatures (AIT) of many of the flammable, explosive substances fall within this temperature range. Objectives: The main objective of this research is to study and evaluate the suitability of PV module applications in an explosive atmosphere with fire safety perspectives through empirical research design. Methods: It is not practically possible to predict the actual fault conditions occurring in PV modules and therefore the worst case conditions are the testing criteria. Shaded and flawed cells are developed to test the worst case conditions. Results & Conclusions: Reverse bias characteristics of PV cells vary based on their shunt resistance. Cells can have either high shunt resistance where the reverse performance is voltage-limited or low shunt resistance where the reverse performance is current-limited. Current research test results published indicate that the PV modules applied in explosive atmospheres can lead to fire hazards even protected through bypass diodes and encapsulation due to unpredictable failure of PV cells.
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Fischer-Tropsch synthesis on Co/Al₂O₃ catalyst: Effects of carbidization and reduction conditions
المؤلفون: Fernando Vallejos-Burgos, Zhendong Pan and Dragomir B BukurAlumina supported cobalt (Co) catalysts are the preferred choice for Fischer-Tropsch synthesis (FTS) when using natural gas as raw material, which is the case of Qatar. It is thus of economical interest to find ways of increasing activity and/or selectivity of these catalysts. One way of modifying catalytic activity, consists of transformation of the active Co phase crystallites. A shift from the abundance of the face-centered cubic (fcc) Co to hexagonal-close packed (hcp) Co phase has been found to increase catalyst activity [1]. This can be accomplished through the carbidization-reduction step with Co carbide as an intermediate. The catalyst was prepared by incipient wetness impregnation of alumina support (15% Co/Al₂O₃). Its fcc form was obtained by reducing calcined catalyst in pure hydrogen at 375°C for 10 h. The hcp form was subsequently prepared by carbidization with pure CO for 14 h at 220°C, followed by reduction in pure hydrogen at 220 or 250°C for 9 h. The catalyst was tested in a fixed-bed reactor at 220°C, 20 bar, H₂/CO ratio of 2 and a space velocity of 3.5 NL/g-cat/h. The figure shows thermogravimetric results during the first reduction step which decreases weight of the sample due to the Co(II,III) → Co⁰ transformation and weight gain during the carbidization step. After 14 h of carbidization, the stoichiometric Co₂C amount is obtained. Temperature programmed hydrogenation and oxidation of this sample showed evidence for the presence of Co₂C and absence of free carbon. CO conversion during FTS decreased from 59% (H₂ reduction) to 55% or 48% after carbidization-reduction pretreatment (at 220 and 250°C respectively); suggesting the need for future studies on alternative reduction/carbidization conditions. Methane selectivity increased from 8% for H₂ reduced catalyst to 11% after both carbidization-reduction pretreatments, probably due to presence of surface and/or bulk carbides. [1] Karaca H. et al. Journal of Catalysis 277 (2011) 14.
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A study on the bacterial infertility and hormonal imbalance in camel (Camelus dromedarius) with the effect of extreme heat of environmental temperature during summer of 2012 in Qatar
المؤلفون: Luningning Mariano CruzA comparative study will be conducted on the presence of bacterial infection and hormonal imbalance in camel (Camelus dromedarius), which precipitates to infertility incongruent with extreme summer heat under field conditions. Parameters are as follows; confinement, feeds consumed, uterine swab, detectable heat cycle, and weight and age of 50 female animal samples. The trial period timetable is 90 days between May and August. Data collected is summarized with blinding and randomization trial design. Maintenance of trial treatment randomization codes and procedures were kept in the electronic record data.
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Dynamic stress state around a nanosized spherical reinforcement due to a scattering of elastic shear waves
المؤلفون: Sinisa BugarinBackground and Objectives Nanostructured devices are finding ever increasing use in industrial applications which has prompted a need to further understand their mechanical properties. Research has shown that as the size of structures such as reinforcing particles and fibres is reduced to nanometers, their particular mechanical properties vary. This variation of the material behaviour has mainly been attributed to surface/interface energy around the free surface or interface of the nanostructures. Since such nanostructured materials exhibit characteristic length in nanometers, their elastic properties are affected by surface stresses that can displace atoms from the equilibrium positions which they normally occupy in bulk macroscopic assemblies. As such properties are not normally noticed in macroscale, as they are limited to only a few atomic layers, the free surface/interface effects are often neglected in the classical continuum mechanics. This paper investigates the effect of the surface/interface elasticity on the dynamic stress state in a matrix around the nano-particle reinforcements due to asymmetric dynamic loading. Methods In the surface/interface elasticity theory, an interface between a nano-particle reinforcement and matrix is considered a negligibly thin surface or a membrane glued to the underlying bulk materials without slipping. The elastic constants of the membrane are different from those of its adjoining materials, and its inertia can be neglected in the dynamic problem. This leads to a set of non-classical boundary conditions at the interface. Results: Different surface properties are investigated under varying frequencies of shear waves as well as different matrix and nano-reinforcement material properties. The stress concentrations values around the nano-particles are found to be significantly dependent on the frequency of excitation and surface properties. The effect is localized near the nano-particle matrix interface and disappears away from the interface into the matrix bulk. Conclusions: Dynamic stress field at the reinforcement-matrix interface is significantly affected by surface/interface elasticity as the reinforcing particle size reduces to nanometers. The increasing surface elastic constant μs can significantly reduce the stress concentration values at the nano-particle matrix interface.
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Instability of damaged pipes retrofitted by a liner
المؤلفون: babak Haghpanah, Abdelmagid Salem Hamouda and Ashkan VaziriBackground: Underground piping systems have a large variety of applications ranging from oil, gas and petrochemical industries to water distribution networks. Presence of defects, particularly cracks, in underground pipes may severely undermine structural stability and makes restoration of the shell's structural integrity inevitable. Replacement of the damaged sections of the pipeline as the most direct restoration approach is costly, hard to execute due to difficulty in physically accessing the damaged sections, and often leads to prolonged interruption in the service. In light of these difficulties, alternative approaches have been proposed in recent years for retrofitting the damaged thin-walled structures by engagement between an inserted, expandable liner and the existing pipe (e.g. Underground Solutions' Duraliner™). Objective: The objective of this project is to examine the stability of the repaired pipelines and to provide a more in-depth understanding of the validity and practicality of the relining process materials and techniques and their limitations. We explored the instability of a cracked thin shell cylinder reinforced with an elastic liner subjected to pure axial compression and also combined axial compression and internal pressure. Method: Finite element models of cracked cylindrical shells with elastic liners for various crack lengths and orientations were developed using a special meshing scheme to accurately capture the crack tip stress intensity. Eigenvalue buckling analysis was used to assess the critical loading and buckling modes. Results: Through our extensive parametric studies, we studied the correlations between buckling response and reinforcement parameters such as the relative thickness and stiffness of the liner and shell layers and damage parameters such as crack size and orientation. Conclusions: While elastic reinforcement significantly improves buckling characteristics of the structure compared to the unreinforced case, there is significant differences in buckling behavior depending on crack size, orientation and the material properties of the shell structure and liner. We find that internal pressure may stabilize against local buckling by suppression at the lower internal pressure zones or, may precipitate local buckling of the reinforced cylindrical shells due to stress concentration at higher internal pressure zones depending upon the elastic and geometric properties of the structure.
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Exceptional CO2 absorption by covalent organic polymers (COPs)
المؤلفون: Cafer Tayyar Yavuz, Hasmukh Patel, Ferdi Karadas, Erhan Deniz and Mert AtilhanEfficient CO2 scrubbing without a significant energy penalty remains an outstanding challenge for fossil fuel-burning industries where aqueous amine solutions are still widely used. Porous materials have long been evaluated for next-generation CO2 adsorbents. Porous polymers, robust and inexpensive, show promise as feasible materials for the capture of CO2 from warm exhaust fumes. We report the syntheses of porous covalent organic polymers (COPs) with CO2 adsorption capacities of up to 5616 mg/g (a world record-measured at high pressures, i.e., 200 bar) and industrially relevant temperatures (as warm as 65 C). COPs are stable in boiling water for at least one week, and near infinite CO2/H2 selectivity is observed. Theoretical calculations refer to an amorphous extended framework as density is likely the main reason for exceptional CO2 capacities. COPs 1-2 feature basic nitrogen sites that show chemospecific affinity towards acidic gases such as CO2. COP-3 has reasonably high surface area (418 m2/g), effective for low pressure operations. Post-combustion carbon capture from fossil fuel power plants demands pressures of up to 6 bar and a minimum temperature of 40 C. By tuning their architecture, we show that COPs reach to 3 mmol CO2/g sorbent at 6 bar and 45 C. High and low pressure capacities make these porous polymer structures viable alternatives to amine scrubbers*. *H. A. Patel, F. Karadas, A. Canlier, J. Park, E. Deniz, Y. Jung, M. Atilhan*, C. T. Yavuz*, J. Mater. Chem., 22, 8431-8437, (2012).
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Nanotechnology methodologies play a unique role in energy production and biomedical applications
المؤلفون: Maan Nassar Al-Ani, Martin Richrdson and Khalid Jabor Al-ThaniBackground and Objective: Today, nanotechnology is being used by many industries and universities to develop new, safe manufacturing procedures for nanostructures, polymeric nanocomposites, polymer photonic components and devices, and other revolutionary biomedical devices and systems with nanoscale functions. Nanotechnological innovations are the key to the safe application of these procedures in science and engineering. Our goal in this study is to minimize the human health risks associated with emergent products and the replacement of existing, harmful products with non-toxic nanomaterials and non-destructive nanodevices. Methods: We propose the use nanofabrication techniques, along with production of new nanomaterials, as a potential avenue to enhance the two fastest growing fields of science and industry, biomedical research and renewable energy. An example of nano- applications in connection with these two very different scientific fields is the use of photon production techniques. We use photon production techniques to harvest energy capable of enhancing solar energy grids, enhancing nanochemical material's ability to absorb heat in nuclear reactors, and to stimulate nanorobotic labeled nanoparticles to kill cancer cells. These photons are produced from two mean light sources--the sun's rays (UV) and lasers. Result: In this study, our data clearly shows the effect of photons on labeled nanomaterials on the surface of nanorobotic devices and shows the ability of these devices to locate and differentiate cancer cells from healthy cells. Parallel to these studies, we are still in the process of collecting data in relation to photons' effect on nanomaterials and their ability to manipulate nanoparticles, allowing for safe energy production in nuclear power reactors. These same photons also have the ability to augment nanomaterials on solar grids, enhancing solar energy production. Conclusion: Data analysis shows that advances in nanotechnology methodologies will play a critical role in achieving greater environmental gains in renewable energy, including safer, more efficient nuclear energy production. Methods of photon applications on nanostructures in biomedical research can be adapted to similar interactions between photons and nanoparticles, leading to the evolution of current energy production processes.
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Development of predictive emission monitoring system algorithms for Qatargas turbine
المؤلفون: Andi Suliono, Mohsin Raja, Claude Sadois and James BaldwinQatargas and Total Research Center Qatar (TRC-Q) established a collaboration to study Predictive Emissions Monitoring (PEMS) algorithms for pilot application on a Qatargas gas turbine to predict NOx emissions. This pilot study was intended to demonstrate to local authorities that PEMS could be a reliable technique in both an alternative and complimentary capacity to Continuous Emissions Monitoring Systems (CEMS). PEMS is an emerging algorithmic solution utilizing process and turbine operational data to estimate emissions from combustion units. Consequently, PEMS do not require routine maintenance and calibration, thus reduced costs, higher availability than CEMS. The approach adopted for the study was a blind-benchmarking comparison of three main PEMS algorithms (first principle, statistical and neural networks). The study was comprised of two phases. Phase 1 was PEMS model development and validation using turbine operational data and corresponding NOx data. Phase 2 involved PEMS model testing, where a different set of only operational data were used to predict NOx emissions. Predicted results of models were then assessed by comparing with corresponding NOx data from CEMS. The study continues, and this paper provides an overview of preliminary study results, challenges encountered and key lessons learned with regard to PEMS development. The initial study results indicated that there is no one specific PEMS algorithm that can be regarded as 'best-suited' to gas turbines that is able to cover a wide range of turbine operational conditions. Preliminary study results for the pilot turbine suggest that PEMS are best suited to predict NOx emissions within the operational range they have been trained for. Hence it is critical to have high quality and reliable turbine operational and monitored NOx data which covers the required range of likely operating conditions. Based on these initial results, the first principle and feed-forward neural network algorithms were found to perform better than the statistical algorithm. The full study results, incorporating improvements based on the above lessons learned, will be discussed in a future paper.
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Genetic diversity of the endangered mangrove species Avicennia marina in Qatar using DNA markers
المؤلفون: Talaat Ahmed and Amna Hussain BabssailMangroves are evergreen trees that grow along the coastal areas of Qatar. The largest and oldest area of mangroves can be found around Al-Thakhira and Al-Khor. Other mangrove areas originate from fairly recent plantings by the government, although unfortunately the picturesque mangrove lake in Al-Wakra has now been uprooted. Avicinnia marina is the predominant mangrove species found in the region. Mangroves protect and stabilize low lying coastal land and provide protection and food sources for estuarine and coastal fishery food chains. They also serve as feeding, breeding and nursery grounds for a variety of fish, crustaceans, reptiles, birds and other wildlife. A total of 21 individuals of A. marina, representing seven diverse natural and artificial populations, were sampled throughout its range in Qatar. Leaves from 2-3 randomly selected trees at each location were collected. The locations were as follows: Al-Rawis, Ras-Madpak, Fuwairt, Summaseima, Al-khour, AL-Mafjar and Zekreet. Total genomic DNA was extracted using commercial DNeasy Plant System (Qiagen, Inc., Valencia, CA) kit. To be used for genetic diversity analysis. A total of 12 (Inter-Simple Sequence Repeat) ISSR primers were used to amplify DNA fragments using genomic DNA. The 12 ISSR primers amplified polymorphic bands among mangrove samples in different areas as well as within each area, indicating the existance of variation within each area and among the different areas of mangrove in Qatar. The results could characterize Avicennia marina populations existing in different areas of Qatar and establish DNA fingerprint documentations for mangrove population to be used in further studies. Moreover, existence of genetic variation within and among Avicennia marina populations is a strong indication of the ability of such populations to adapt different environmental conditions in Qatar. This study could be a warning to save mangrove in Qatar and save the environment as well.
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Forecasting breaks of oil and gas pipelines
المؤلفون: Mohamed El-Abbasy, Ahmed Senouci and Tarek ZayedEven though oil and gas pipelines are the safest way to transport petroleum products, they still break generating hazardous consequences and irreparable environmental damages. Many models have been developed in the last decade to predict pipeline failure and conditions. However, most of these models were limited to one break type, such as corrosion, or relied mainly on expert opinion analysis. The objective of this paper is to develop a model that predicts the break cause of oil and gas pipelines based on factors other than corrosion. A fuzzy-based model was developed to help decision makers predict break occurrence using fuzzy expert system (FES) according to historical data of pipeline accidents. The model was able to satisfactorily predict pipeline breaks due to mechanical, operational, corrosion, third party, and natural hazards with an average percent validity of 93%. The developed model will assist decision makers and pipeline operators to predict the expected break cause(s) and to take the necessary actions to avoid them.
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Inter- and intra-specific genetic variations among Qatari date palm cultivars using inter simple sequence repeat (ISSR) markers
المؤلفون: Talaat Ahmed, Sarah Al-Hadidi and Asmaa Al-QaradawiDate palms are generally propagated by separating the offshoots produced by individual trees. This method maintains the genetic integrity of date palm cultivars. Individual trees of well-known Date palm cultivars have little differences in fruit morphological characters and quality especially color and sweetness. The objectives of the present study are to analyze the genetic diversity among most common cultivars of Qatari date palm as well as the genetic variation within each cultivar. Five common Date palm cultivars in Qatar were selected including Khalas, Sheshy, Rezezy, Barhee and Khanezy from three different locations (Al-Shamal, Al-Khour and Al-Rayan). This study tried to answer basic questions about the genetic similarity or diversity among and within the well-known Qatari date palm cultivars using 18 Inter Simple Sequence Repeat (ISSR) primers. All primers have amplified polymorphic bands in the studied cultivars either among the cultivars or within each cultivar in different cultivated areas. The results indicated the existing of genetic variations among well-known cultivars as well as within each cultivar explaining the variation in some morphological and quality characters for different trees of the same cultivar that are grown in different environments.
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Assessment of organic Rankine cycle performance with binary working fluid mixtures
المؤلفون: Mirko Stijepovic, Patrick Linke and Athanasios PapadopoulosOver the past several years organic Rankine cycle (ORC) processes have become a promising technology for power production from low grade heat sources, such as solar, biomass, geothermal and waste heat. A key challenge in design is the selection of an appropriate working fluid. ORC systems that use single components as working fluids have two major shortcomings. First, in the majority of applications, the temperatures of the heat sink and source fluid vary during the heat transfer process, whereas working fluid evaporation and condensing is isothermal. As a consequence a pinch point is encountered in the evaporator and condenser giving rise to large temperature differences at one end of heat exchanger. This leads to irreversibility that in turn reduces process efficiency. A similar situation is also encountered in the condenser. A second shortcoming of the Rankine cycle is its lack of flexibility. For given operating conditions, a certain working fluid may be the optimum choice; however, as the operating conditions change another working fluid would become a more appropriate choice. The shortcomings result from a mismatch between thermodynamic properties of pure working fluids, the requirements imposed by the Rankine cycle and the particular application. In contrast, when working fluid mixtures are used instead of single component working fluids, improvements can be obtained in two ways: through the inherent properties of the mixture itself, and through cycle variations which become available with mixtures. The most obvious positive effect is decrease in exergy destruction, because occurrence of the temperature glide at phase change provides a good match of temperature profiles in condenser and evaporator. The paper presents detailed simulations analysis of organic Rankine cycle processes for energy conversion of low heat sources for various binary zeotropic mixtures. The rigorous and the most suitable thermodynamic models are applied in each mixture simulation. The paper explores the effect of mixture utilization on common ORC performance assessment criteria in order to demonstrate advantages of employing mixtures as working fluid as compared to pure fluids. In addition, several new criteria are developed in order to provide a new perspective on how ORC performance should be assessed from thermodynamic point of view.
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Combined heat and power generation using industrial zones waste heat
المؤلفون: Mirko Stijepovic and Patrick LinkeThe basic materials industry contributes significantly to global energy demand. The efficient utilization of energy in these industries is essential to sustainable development. In numerous emerging countries, such industrial activity is concentrated in industrial zones. Typically, significant energy savings can be achieved through the exploitation of symbiotic relationships between companies within such zones. The identification of symbiotic relationships calls for systems approaches to energy integration, which have been identified as crucial enablers of sustainable solutions in the basic materials industries. This work establishes a systematic approach to target heat and power cogeneration potentials within industrial zones and to design the corresponding optimal waste heat recovery and reuse networks. The initial focus of the approach is on retrofit solutions that reuse heat and extract power through existing utility systems. The approach assumes that quantities of heat from source plants, which are reaching sink plants, are only limited by heat requirements of sink plants. This work extends our previous efforts by developing an approach to reveal combined heat and power opportunities that increase power production and offset heating requirements. The proposed approach enables targeting and concrete integration options based on economic criteria. The application of the approach is illustrated with a case study.
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Threat resistant sandwich walled structural system
المؤلفون: Hamid Ebrahimi, Abdel Magid Hamouda and Ashkan VaziriBackground: Sandwich panels with low density core constructions are a class of structural elements with superior structural performance compared to traditional solid panels. Sandwich panels, compared to solid panels of equal mass, generally have much higher bending stiffness and comparable stretching stiffness, thus undergoing smaller deformation under loading. The potential advantage of sandwich panels for mitigating shock and projectile loading has been established in literature. The previous studies related to understanding the mechanics and structural performance of sandwich structures are mainly focused on studying the behavior of the core construction or the performance of a single isolated sandwich panel. These studies have provided significant insight into the behavior of sandwich panels, which includes mechanisms of energy dissipation in the core, stages of deformation of sandwich panels as they get impinged by an intense shock, fluid-structure effects for shock waves transmitted in air and water, and the mechanism of deformation and failure of sandwich panels under shock and projectile loading. Objective: This study extends previous research by exploring the behavior and structural performance of structural systems made of sandwich walled panels. The objective is to explore the potential benefit of sandwich configurations in enhancing the overall behavior of structural systems under complex loading conditions that could occur in petrochemical industry settings and pipeline networks. Method: We considered three frame structures, (i) frames made of solid panels (ii) frames with sandwich panel side walls and (iii) frames where all walls are made of sandwich panels. We also considered sandwich walled cylinders resembling pipes and compared their performance with the mechanical behavior of traditional pipes made of solid metal hollow cylinders. We used detailed finite element models to simulate the response of these structural systems. Results: The results showed that sandwich walled frame and cylinder (pipeline) configurations, in general, undergo smaller deflection than traditional counterpart structures under both quasi-static and high intensity dynamic (shock) loadings. Conclusions: The results highlight the potential of sandwich walled structural systems for developing novel threat resistant structures especially for the petrochemical industry and pipeline networks.
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Cost and efficiency to achieve grid parity
المؤلفون: Fedaa AliAlthough direct conversion of solar energy to electricity by photovoltaic cells, or thermal energy in concentrated solar power systems is emerging as a leading contender for next generation green power production, solar energy contribution to a sustainable energy future begins from a much smaller base than oil and natural gas. The infrastructure as well as the human capacity to support solar power production on the same scale as the oil and natural gas industry does not currently exist. Therefore, it is vital to select research and development portfolios that will reduce risks of investment in solar projects that will help motivate deployment of new technologies. At present, photovoltaic (PV) cells are predominately based on crystalline and polycrystalline silicon and are growing at >40% per year with production rapidly approaching 3 gigawatts/year with PV installations supplying <1% of energy used in the world. Crystalline silicon-based systems will remain the dominant photovoltaic technology in the short term, but thin films are steadily increasing their market share too. There is also the use of multi-junction cells or hybrid devices organized at the nanoscale, the nanostructured photovoltaics. Increasing cell efficiency and reducing manufacturing expenses are critical in achieving reasonable costs to achieve grid parity. The paper includes analysis of the most challenging technological barriers in achieving low cost, high performance power conversion for photovoltaics, and promising R&D paths to meet such challenges. Objectives: Forming a platform that focuses on narrow cross-cutting areas within the research and technology chain to achieve low cost, high performance power conversion for photovoltaics. Methods: A review was carried out that included an analysis of emerging manufacturing technologies and ongoing material research in the context of the current industry situation. Results and Conclusion: Generally, there are two major avenues to further reduce the cost of energy generated by PV materials: (i) Reduction of manufacturing prices while retaining reasonable energy conversion efficiency (10-12%) and lifetime of devices (the major drive of which is in the development of thin-film solar material); (ii) Approaches focused on increasing the energy conversion efficiency beyond the Shockley-Queisser limit, while keeping a reasonable manufacturing cost.
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Properties of 2:1 aqueous strong electrolytes using the Q-electrolattice equation of state
المؤلفون: Ricardo Figueiredo Checoni, Andre Zuber and Marcelo CastierElectrolyte solutions occur in many natural systems and are present in several industrial processes. Aqueous solutions of electrolytes are particularly important for designing water purification and treatment systems, among which water desalination processes. The design of processes with electrolyte solutions may require determining phase equilibrium conditions, and predicting volumetric and calorimetric properties. Equations of state (EOSs) are, in principle, capable of such predictions and, for this reason, a several equations of state (EOS) have been developed considering the ionic interactions in electrolytes solutions. An example is the electrolattice equation of state. This model evaluates the Helmholtz energy as the summation of three contributions: the first considers the short range interactions (by using the Mattedi-Tavares-Castier equation of state (MTC-EOS)); the second, the Born contribution term, accounts the solvation effects; the third, the primitive mean spherical approximation (MSA) term, describes the long range effects. In the electrolattice EOS, the diameters of cations and anions are considered to be equal. In this work, we calculate vapor pressures, mean ionic activity coefficients, osmotic coefficients, and densities of mixtures containing water and a single 2:1 strong electrolyte with a revised version of the electrolattice EOS, which is called Q-electrolattice EOS. The latter preserves the first and the second contributions of the electrolattice EOS, but includes another MSA term, which is an explicit mean spherical approximation under the assumption the ions have unlike diameters. The water molecule is assumed to have a dispersion region, an electron-donor region, and an electron-acceptor region. To reduce the number of adjustable parameters of the model, the ionic diameters are taken from the literature. Also, interactions between the each ion and each of the three regions of the water molecule are assumed to be equal. Finally, short range interactions between ions are neglected. With this set of assumptions, the inclusion of each ion only requires the fitting of one additional parameter. The work compares the performance of the electrolattice and Q-electrolattice models with respect to other equations of state for similar applications.
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Studying oil production allocation and well integrity by fingerprinting, biomarkers and isotopic ratios and studying the deconvolution of the commingled production
المؤلفون: Hend Saleh HASSAN, Daniel DESSORT, Nizar JEDAAN, Abdulrahman AL-KAABI and Mohamed AL-ALIFingerprinting studies of crude oil can solve many production allocation problems and well integrity issues that the operators can face in fields with commingled production. It can also be a very effective tool to know which portion of original hydrocarbon reserves has not yet been produced without interrupting the current production. In this paper, we will see the major role of the organic geochemistry techniques in solving these production allocation issues. In the Total Research Center Qatar (TRC-Q), we are using many techniques to help solve the production allocation problems. One of the most powerful techniques for this type of studies is high performance gas chromatography fingerprinting, which can discriminate the differences between oils from different reservoirs and different layers and can also help in discovering comingled production by analyzing the oil samples and comparing the most discriminated molecular ratios among all of the analyzed samples. The interpretation of these results will provide a very clear indication of the similarities and differences associated with the samples. Besides this technology, we are performing a further step: biomarkers studies to identify the origin (geological formation) of the crude oil. This technique compares oil samples based on the mass/charge ratios. These results are then interpreted to give a clear identification of the origin of the samples. Isotopic studies are significant part of what we are performing in TRC-Q. They give the most effective and precise results for discriminating different oils and identifying any concern regarding production allocation and well integrity. A great example that demonstrates all of the above mentioned analytical techniques is a study that TRC-Q performed in collaboration with Qatar Petroleum where all of the fingerprinting techniques have been used in a blind test to identify the source and origin of five unknown oil samples.
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Criticality measures for components with multi-dimensional degradation
المؤلفون: Liu Xiao, Khalifa Al-Khalifa, Abdel Magid, David Coit and Elsayed ElsayedBackground: Many failures of engineering structures and equipment are attributed to the failure of a single component. It is of great importance to identify those critical components and understand how components' criticality changes over time under dynamic environments. Objective: In this paper, we investigate the criticality analysis for components with multi-dimensional degradation under time-varying environmental conditions. Methods: The component degradation is modeled as a k-dimensional Wiener process and a component fails when any of the k degradation processes attains a threshold level. Results: Since the degradation process is often influenced by the environmental conditions, we assume that both the mean and diffusion of the degradation process are time-dependent functions for a given environmental profile, which evolves either deterministically or stochastically. Conclusions: We derive expression for the criticality measure of the component with time, illustrate the analysis of component criticality under time-varying environmental conditions and demonstrate the necessity to consider the change of environmental conditions in analyzing component criticality.
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Future energy independence in the western hemisphere: Impact on Qatar and the Gulf region
المؤلفون: Remi PietRecent projections for energy production on the American continent (from Canada to South America) are suggesting a potential energy independence for the western hemisphere in the next fifteen years. The very large newly found oil reserves (mainly off the coast of Brazil), the technological progresses (allowing for the safe exploitation of tar sands in Canada) and the natural gas potential of shale gas in North America are changing the energy equation on the other side of the Atlantic Ocean. What has been historically the Gulf region's main customer of hydrocarbons is likely to significantly decrease its import in the near future. Although other emerging regions (India, China, Africa) should make up for this loss in the short term, the global efforts to mitigate climate change is bound to encourage natural gas consumption over oil. GCC countries will thus face a strong challenge to diversify its customer network and adapt their energy mix production drifting away from oil towards natural gas and renewables. Each of the GCC countries will face different challenges depending on their resource endowment and infrastructure network. This research aims at analyzing the potential domestic impact of this new scarcity of demand. Each country in the Gulf region has developed a unique set of domestic institutions and economic structures whose resilience will be challenged. This research implements comparative politics theories and lenses, especially Thomas G. Moore's framework of analysis assessing state's capacity to absorb external shocks and issue national responses for economic adjustment (Cambridge, 2002). It also reverses the argument developed by Ikenberry (Princeton) on European and American countries comparative economic responses to the oil shock in the 1970s. The objective of this study is to inform Gulf countries' governments of the best original set of proactive policies and reforms that should be adopted to ensure sustainable development, social progress, political stability and economic transition.
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