Qatar Foundation Annual Research Forum Volume 2012 Issue 1

Heterogeneous 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.

In 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.

Reactions 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.

Blister 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.

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.

According 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.

Supercritical 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.

Background: 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.

The 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.

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.

Total 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.

Introduction: 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.

The 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.

Nanoparticles, 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.

Natural 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.

Alumina 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.

Background 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.

Efficient 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).

Qatargas 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.

Even 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.

Over 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.

Background: 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.

Electrolyte 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.

Background: 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.

It's been many years since the invention of the internal combustion engine. These engines are getting more challenging due to the concerns of ever increasingly harmful pollutions and limited energy sources. Environmental regulations have been more restrictive, and car manufacturers have invested more into reducing emitted pollutions and fuel consumption. It is well recognized that for spark ignition (SI) engines, the air-fuel ratio (AFR) is by far the most dominant factor in determining the engine exhaust gas mixture and the amount of lit/km characteristics. For many years this has been partially addressed due to the restrictions on the control approaches because of existence of a time delay in the control input. The control approach presented in this research provides a novel strategy based on the internal dynamics of SI engines. It compensates for the delay at each instant and follows the desired trajectory of AFR. This leads to a reduction of fuel consumption and keeps the actual AFR close to the stoichiometric AFR, which indeed minimizes the harmful pollutants. The research proposes a thorough design methodology that circumvents the previous limitations for industrial PID controllers in terms of noise attenuation. It is robust against canister purge disturbances, modeling uncertainties, parameter variations and time-varying engine operating conditions. The proposed controller has been implemented on experimental data collected at University of Houston on a FORD F-150 truck. The results have shown considerable improvements over the baseline controller and exhibited excellent performance for the noisy outputs of the sensor due to the aging factors.

Realization of multilevel inverters for multiphase high power AC drives with open-end windings is presented in this paper, with a specific case of five-phase five-level inverter configurations. The five-level voltage profile is realized by feeding both ends of the stator windings using a three-level five-phase flying capacitor inverter on one side and a five-phase two-level inverter on the other side. The flying capacitors' voltages are effectively balanced by utilizing the switching state redundancies. The capacitor voltages can be balanced at any modulation index, irrespective of the operating power factor. The operation of a drive at a higher voltage is preferred in many applications due to the advantages such as higher efficiency and reduction in size and weight. However, this demands higher DC link voltage in many topologies. The DC voltage magnitude required in the proposed topology is half of that required in the conventional multilevel neutral point clamped (NPC) topology, for a given output voltage. Hence, the scheme proposed in this paper can be advantageous in such applications where there is a limitation in obtaining DC voltage sources of higher magnitudes, such as in electric and hybrid electric vehicles. Another attractive feature of this topology is the enhanced reliability, as it is possible to operate the drive with half power even if any one of the inverters completely fails. The number of active switches used in this topology is lesser than that in equivalent five-level NPC inverters. Unlike the NPC inverter, this topology does not require any clamping diodes and is also free from issues like neutral point fluctuations. A carrier based pulse width modulation (PWM) technique combined with a hysteresis controller for balancing of the capacitors' voltages is used for the control of the inverter. The proposed drive topology can be applied to high power AC drives such as in oil and gas industries, electric/hybrid electric vehicles, ship propulsion, traction etc. The simulation and experimental results support the proposed idea.

The countries of the Gulf Co-operation Council (GCC) have established an interconnected power system network. The primary goal was to share the spinning reserve among the GCC power grids. The project considered the commercial use of the network by aiming to reduce the cost of power generation in the six GCC states while encouraging power trade in order to meet growing needs. The GCC interconnection authority proved its effectiveness and success when, after it was set up, the interconnection contributed in avoiding any partial or total blackout. This was done by passing supported power to any of the first phase connected states. After connecting the first phase of the project, none of the states were compelled to cut loads from their customers. Furthermore, the probability of having a blackout or power shortage has been reduced. The GCC's ambition did not stop at this point. The hope is to connect to neighboring power grids, which could potentially connect to the European Grid. The link, if it took place, would mean great commercial benefits, since peak load seasons in European countries are different from those in GCC countries. In this paper, a study includes an overview of the GCC interconnection, and its benefits are presented. This would emphasize the transfer capability in an interconnection, especially in Qatar, using PSSE program. Moreover, it considers maximizing this capability as a future need to transfer more power through the network. Flexible Alternating Current Transmission System (FACTS) devices are proposed for such purpose. A thyristor controlled series capacitor (TCSC) is selected for enhancing the power capability. This includes an overview, design, and simulation using MATLAB/SIMULINK of TCSC controller.

Cadmium is a naturally occurring metal and is usually present in the environment as a mineral combined with other elements, such as oxygen, chlorine, and sulfur, or as a minor component of most metal ores such as zinc, lead, and copper. Cadmium is also released in the environment from industrial activity; in particular, ore-smelting plants, industrial paints, and agricultural fertilizers. Over the last few decades, considerable attention has been paid to the evaluation and detection of cadmium contamination in the environment, mostly because of the relationship between cadmium exposure and the development of chronic health problems, including renal dysfunction, osteoporosis, and carcinogenesis, as well as developmental and reproductive problems. Water contamination by cadmium is of particular interest because of its high solubility in acidic conditions. Contamination of drinking-water may occur as a result of the presence of cadmium as an impurity in the zinc of galvanized pipes or cadmium-containing solders in fittings, water heaters, water coolers and taps. The aim of this study is to evaluate the availability of cadmium in drinking water in Qatar. Five samples of municipal water were collected from different locations in Doha--Al-Wakra, Dafna, Salwa Road, Al-Kharitiyat and Sailiya--to examine the availability of cadmium in drinking water. Analysis was performed by injecting the samples directly into an ICP-OES machine and obtaining the results. The results showed that the cadmium concentration in all samples was below detection (detection limit for Cd: 0.7 ppb). These low Cd concentrations in drinking water in Doha may be related to the fact that both dissolved and particulate matter are being removed from seawater during the desalination process. In addition, the absence of these toxic elements may be related to the water distribution system being relatively recent and containing cadmium-free pipes.

Qatar established it vision 2030 in October, 2008 (Ibrahim, 2009), adopting the concept of sustainable development. Thus the understanding of the impact of poor wastewater management and degrading sewage systems should be highlighted. Additionally, new technology should be developed to fully decrease the pollution while focusing concern on the economic benefits of the process. We have chosen to evaluate both poultry and slaughterhouse wastewater, since, if discharged into open waterways in an untreated form, it can cause great pollution stress on our environment. To be able to build a proper process for wastewater treatment, we had first to choose the characteristics needed to be identified for better understanding of the local wastewater, to later have informative values at the end. To help us fully understand the chemical and physical characteristics of the wastewater to be treated, we have chosen to measure initial parameters, including chemical oxygen demand (COD), total suspended solids, total dry solids, pH and conductivity. It is well-established that slaughterhouse wastewater is a moderate to low strength complex-type wastewater; thus, the biodegradability of this could be easily achieved if an adapted bacterial population is obtained. Interestingly, we showed that the anaerobic sludge from the Qatari environment is able to treat more than 95% of the wastewater at 38°C, which is favorable and beneficial to develop large-scale anaerobic digestion of the slaughterhouse waste waters given the conditions in Qatar. Consequently, it is possible to conclude that the anaerobic sludge and the temperature applied for the treatment are suitable to overproduce methane from slaughterhouses wastewaters in Qatar's conditions. Our findings showed that almost 1.3 L of methane can be produced by digesting 1 g of COD or dry matter in the slaughterhouse wastewater, which is a very high yield, unprecedented among levels reported for anaerobic digestion.

Companies around the world produce waste as a by-product of their products. The waste products are classified as solid wastes, medical wastes, wastewaters, and different kinds of wastes. Overall, the wastewaters have the highest impacts on the environment, since they are discharged into the seawater, and might also be discharged into the municipal wastewaters. In addition, the composition of the wastewater varies from one company to another, but mainly it contains different kinds of solids either organic or inorganic. The wastewater coming from the slaughterhouses and the poultries is considered one of the most high-impact effluents because of its complex composition. Therefore, the main goal of the project is to use the aerobic reactors in order to treat the wastewater coming from the slaughterhouses and the poultries. The methods used in the project to monitor the efficiency of the treatment, were basically monitoring the changes in the chemical and physical characteristics, like, COD and pH of the effluent during the treatment process, and then to calculate the efficiency of the treatment and the loading rate. The results obtained provided us with the variability of the organic pollutants in the wastewater. For example, the pollution caused by the wastewater coming from both the poultry slaughterhouse and the Mawashi slaughterhouse was low, and the treatment efficiency for the poultry and the slaughterhouse was about 83% and 86%, respectively. In addition, with the loading rates used in the experiment, the efficiency was about 90%, which means that if the residence times increased, the activated sludge reactor would digest the organic pollutants completely.

Nanotechnology is foreseen to change our life by bringing new horizons to current industrial applications. It could be used, for example, to improve the performances of heat exchangers--which are widely used in industrial applications--by augmenting heat transfer characteristics of the working fluids. Nanofluids, which are engineered colloidal suspensions of nano-sized particles (less than 100nm) dispersed in a base fluid, have shown potential as industrial cooling fluids due to their reported enhanced heat transfer characteristics. However, rheological characteristics of nanofluids at extreme working conditions that occur in industrial applications are not well studied. This work for the first time presents the rheological characteristics of cooling oil based nanofluids at high temperatures and pressures. In this work, nanofluids are prepared by dispersing SiO2 nanoparticles (~20nm) in a highly refined paraffinic mineral oil (Therm Z-32, QALCO) that has wide applications in industrial heat exchangers, especially in NGL plants operated by Qatar Petroleum. Three particle concentrations of 1%, 5% and 10% by weight are considered for the investigation. The high pressure and high temperature viscosity values are measured using a HPHT viscometer (METEK CHANDLER ENGG.). In the experimentation, viscosity values of the nanofluids are measured at temperatures ranging from ambient to 160oC, with pressures varying from atmospheric to 100 atmospheres. Initial observations have shown that variation in particle loading and temperature affects the viscosity of nanofluids, whereas increases in pressure had a negligible effect on nanofluids viscosity.

Qatar has experienced an unprecedented development in recent years as a result of its large oil and gas industry. It has the third confirmed reserve of natural gas in the world. With 55.4 tonnes of carbon dioxide per person, Qatar has the highest carbon footprint globally, about 10 times the global average. Against this background, there have been attempts to investigate ways to reduce carbon emissions since CO2 was deemed to be one of the major green house gases. Power generation is by far the biggest contributor to anthropogenic (man-made) carbon emissions. The carbon emission mitigation methods currently considered include both “end of pipe” and “at source” solutions. The techniques currently identified to capture carbon emissions from point sources from industrial activities include post combustion capture, precombustion capture and oxyfuel based capture. These techniques are currently at various stages of development. In this work, an important petrochemical process, namely the Vinyl Chloride Monomer (VCM) process has been selected for carbon footprinting. The primary fossil fuel equivalents, which in turn will be turned into CO2 emissions using combustion processes, were identified. Industrial standard simulation software HYSYS was used to carry out the calculations on the heat duties of the entire plant. Energy intensive sections in the VCM process were identified and their associated CO2 footprint calculated. The total CO2 emissions from VCM plant with a hypothetical capacity of 300,000MT/yr were estimated to be around 96,000 MT/yr, which means that for each 1 ton VCM produced, 0.32 ton of CO2 is emitted. In addition to the process related carbon emissions, non process CO2 emissions were estimated. This emission emanates from energy used to power lighting, electronic equipment, catering, in-house transportation etc. Good practice for energy saving and hence CO2 emission reduction was put forward.

Carbon capture and sequestration (or carbon capture and storage, CCS) is considered to be a critical strategy worldwide--and in Qatar as well--to limit carbon dioxide (CO2) emissions; the main greenhouse gases responsible for global warming. This work focuses on designing a simple device for CO2 capture that can be used in mobile systems like vehicles and ships. The device mainly consists of a compact cylinder filled with an absorbent solution for CO2 emissions. A distributor with a special design is used to increase the area of contact between CO2 gas and the solution in order to increase the absorbent efficiency. Figure 1 shows a schematic diagram of the test rig. Different materials that have high absorption characteristics of CO2, such as NaOH and MgOH, have been used to evaluate the device performance. At the first stage of this work, the CO2 emission has been simulated by injecting a mixture of CO2 and N2 into the device to be used as a proof of concept. A number of parameters, including absorbent material concentration and a mixture (CO2/N2) flow rate, are tested in order to reach the maximum absorption efficiency. CO2 percentage is measured at the entrance and exit of the device to calculate the absorbent ratio with the time. The second stage of this work will include testing the device within an actual internal combustion engine in order to evaluate the device under actual conditions.

Most countries in the world are faced with the dilemma of missing one or more crucial ingredients that prevent them from engaging in environmental research or implementing environmentally friendly policies and practices. Some countries that have the resources to affect change suffer from a lack of political will, whereas others that may have the political will lack the human or technological resources or institutional capacity to affect a change. At present, Qatar is in a unique position for enhancing its environmental performance and sustainability. Endowed by a small population and the world's third largest natural gas reserves, economic resources pose little restraints, and could be converted into building a cleaner future. Education City, Qatar's leading vehicle for building a knowledge economy, incorporates some of the most ambitious environmental sustainability projects and initiatives in Qatar, including sustainable buildings seeking LEED-certification, environmental awareness campaigns, and related practical applications in the areas of solar energy, among others. Apart from this unique concentration of institutions, projects and practices relating to environmental sustainability, the City's cultural diversity makes it a true melting pot of values, perspectives and lifestyles relating to the environment. Education City could provide lessons or even serve as an example of an environmentally sustainable community for the broader society, or will it simply remain a self-proclaimed green community with little impact outside its boundaries? In other words, is Education City a green beacon or is it a green island? This study, funded by the UREP channel of the QNRF, aims to explore environmental sustainability in Education City (EC) and answer the main research question by answering three interlinked, complementary sets of questions, namely: 1) What are the intersections of the vision and EC? 2) How is EC advancing (in) environmental sustainability? 3) Are the university students in EC environmentally sustainable? How about university students in Qatar in general? In addition to providing answers to these questions through qualitative analysis and a survey administered among different universities in the autumn of 2012, this study will seek to identify policy advice and practical applications for environmental sustainability education in Education City and throughout other universities in Qatar.