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
361 - 380 of 469 نتائج
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Self-cleaning performance of polyvinylidene fluoride-zinc oxide composite coatings for civil and industrial applications
المؤلفون: Adel MohamedSynthesis of super/hydrophobic solid surfaces is an active area of research in recent years because it forms the basis for multidisciplinary applications such as agricultural, environmental, and biological processes, such as the prevention of the adhesion of dust to antennas and windows, self-cleaning traffic indicators, waterproof and corrosion resistance coatings. Inspired by the self-cleaning behaviour of lotus leaves in nature, a simple coating method was developed in the present work to facilitate the bionic creation of super-hydrophobic surfaces on various substrates. Due to the chemical stability and flexibility, polyvinylidene fluoride (PVDF) membranes are widely used as the topcoat of architectural membrane structures, roof materials of vehicle, and tent fabrics. Further modified PVDF membrane with superhydrophobic property may be even superior as the coating layer surface. The present study aims to provide a better understanding of the effects that the addition of zinc oxide (ZnO) nanoparticles would have on the hydrophobic properties of PVDF using one-step facile spray-coating process. The surface was prepared through spray coating of a mixture of PVDF and ZnO nanoparticles on aluminum substrate. Stearic acid was added to improve the dispersion of ZnO. The Taguchi method was used to rank several factors that may affect the superhydrophobic properties in order to formulate the optimum conditions. The crystallinity and morphology of PVDF-ZnO membranes were determined by FTIR and SEM. The results of the Taguchi method indicate that the ZnO and Stearic acid contents were the parameters making significant contribution toward improvement in hydrophobicity of PVDF composites. As the content of ZnO nanoparticles increased, the values of water contact angle increased, ranging from 122o to 159o, while the contact angle hysteresis and sliding angle decreased to 3.5° and 2.5°, respectively. The SEM results show that hierarchical micro-nanostructure of ZnO plays an important role in the formation of the superhydrophobic surface. FTIR results showed that, in the absence or present ZnO nanoparticles, the crystallization of the PVDF occurred predominantly in the ß-phase. The coatings proved to be an especially useful class of liquid repellent materials due to their low surface energy, and the roughness characteristics of the aggregates.
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Remote sensing research project: Satellite imagery evaluation for environmental classification in Qatar
المؤلفون: Eric Febbo and Cecile RichardQatar is facing unprecedented development both inland and in its surrounding waters. While the natural environment is not yet fully characterized, there is a need for managers to have an accurate overview of it as a decision making tool and a baseline study for monitoring the future changes. Remote sensing techniques are cost effective in their ability to cover great areas and provide information in a time and cost efficient manner. Development of new sensors such as the WorldView2 satellite and airborne hyperspectral sensors provides highly accurate data including habitat, and superficial soil characterizations. Finer scale techniques such as acoustic surveys can be deployed to compliment study areas of particular interest. Finally, data have to be verified and validated by visual field observations. Implementation of these new techniques for producing a large-scale geographic information system data set for Qatar would highly improve the current knowledge and provide a powerful decision making tool for environmental management and policy decisions. In this context, WorldView2 satellite images have been evaluated as a first step in the remote sensing research program to test the potential of such data for coastal mapping. The objectives of this project were to: test the standard strategies generally used for high resolution imagery processing taking advantage of the new specifications of the sensor (8 spectral bands), and to develop innovative methods for bathymetry estimation and sea bottom characterization. Preliminary results indicate that accurate classifications are possible; habitats such as coral patch reef structures, seagrass and soil classifications have been identified in agreement with the validation field surveys. This is the first step in a multi-faceted approach to utilize the latest remote sensing technologies.
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Pore water gradients below microbial mat surface of Umm Alhool sabkha in Qatar
المؤلفون: Abdul Munem Al-Raei, Mohammad Al-Najjar and Roda Al-ThaniThe mineralization of organic matter in marine sediments by microbial activity was studied in Umm Alhool sabkha. In intertidal surface sediments, the development of steep compositional and physico-chemical gradients was a common phenomenon. Rapidly, oxygen is consumed within the upper few mm of marine mats and sediments. In permeable sediments, however, oxygenated bottom waters may have flew through the upper part of the surface sediments leading to enhanced participation of oxygen in element cycling. Whereas in microbial mats, the surface sediments are locally formed, indicating a disturbance in the balance of the biogeochemical processes. Umm Alhool sabkha, situated between Umm Sa'id (Mesaieed) and Al Wakrah, drew our attention to study the biogeochemical cycling because both microbial mats and mangroves ecosystems affect its biogeochemistry. In the present study, the chemistry of pore water below mats surfaces of intertidal sandy sediments was investigated in winter 2011 using a number of different techniques. Pore water was sampled down to 20 cm below surface using pore water lances, diffusion samplers, and centrifugation of sediment core sections. Microsensor measurements of sulfide and pH were also performed on the upper 2 cm. Specifically, we measured salinity, dissolved O2, pH, SO4²¯, H2S, Cl¯, TN, TOC, PO4³¯, NO3¯, NH4+, H4SiO4, and microbial sulfate reduction rates have been analyzed using intact sediment cores. Sulfidic sediments were characterized by high sulfate reduction rates exhibiting maxima between about 5-15 cm, associated with decreased oxygen penetration depths, and proton activities. Anaerobic metabolic activity in pore waters below mat surface lead to significantly enhanced concentrations of sulfide, ammonium, dissolved inorganic carbon, phosphate, silica (steep gradients), and a net consumption of sulfate. They acted as windows for the liberation of reduced substances into the bottom water or the atmosphere. This study represents the first comprehensive investigation of the chemical composition and sulfate reduction rates in Umm Alhool microbial mat ecosystem. It shows how dynamic and self-fueling the system is.
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Outbursts and cavities in comets
المؤلفون: Sergei IpatovIn 2005 the impact module of the Deep Impact (DI) spacecraft collided with Comet 9P/Tempel 1. Based on analysis of the images made by this spacecraft during the first 13 minutes after the impact, Ipatov and A'Hearn concluded that the triggered outburst of small particles and excavation of a large cavity with dust and gas under pressure began at te= 8s, where te is the time after the DI collision. Schultz et al. analyzed images of Comet Tempel 1 made by the Stardust spacecraft and supposed that the diameter of the transient DI crater (dtc) was about 150-200m. Some authors support smaller values of dtc (up to 50m). My recent studies were devoted to estimates of the distance between the upper border of the cavity (dcav) excavated at te= 8s and the pre-impact surface of the comet. In particular, I supposed that the depth of a growing crater is proportional to te^gamma (where gamma is about 0.25-0.4) during the intermediate stage of crater excavation. The most probable estimate of dcav was about 0.1dtc*(te/Te)^0.3+1 meters, where Te is the duration of the normal ejection (Te=500 s at dtc=150 m). Using this approach I obtained dcav to be 5 or 6 meters for dtc equal to 150 or 200 m (dtc is 3 or 4 m for dtc ~ 50-100 m). The obtained values of the depth are in accordance with the depth (4-20 m) of the initial sublimation front of the CO ice in the models of the explosion of Comet 17P/Holmes considered by Kossacki and Szutowicz. The porous structure of comets provides enough space for sublimation and testifies in favor of existence of cavities. Natural outbursts were observed for several comets. Our studies testify in favor of that cavities with dust and gas under pressure located a few meters below surfaces of comets can be common. Similarity of velocities of particles ejected at triggered and natural outbursts shows that these outbursts could be caused by similar internal processes in comets.
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Whale shark aggregations and biodiversity in the Arabian Gulf - an example of research collaboration between authorities, research institutions and the oil industry in Qatar
المؤلفون: Steffen Sanvig Bach and Mohammed Al-JaidahAl Shaheen is located in the central part of the Arabian Gulf and represents the largest offshore oil field in Qatar. Maersk Oil is operating the field on behalf of its partner Qatar Petroleum. This area is also a highly productive marine environment due to a combination of high nutrient loading, strong currents and high temperatures. Observations first reported by offshore platform workers suggest that Al Shaheen hosts one of the world largest aggregations of whale sharks (Rhincodon typus). The whale shark is listed as vulnerable on the IUCN Red List of Threatened Species and is the largest fish in the world. The Qatar's National Vision (QNV) for 2030 aims to direct Qatar towards a balance between developmental needs and the protection of its natural environment. In order to contribute to QNV, Maersk Oil has established a research and technology centre (MO-RTC) in the Qatar Science and Technology Park with a budget of more than US$ 100 million over a 10-year period. Enhancing oil recovery and minimising impact on the marine environment are key research themes at MO-RTC. Therefore, MO-RTC has signed a memorandum of understanding with the Ministry of Environment Qatar (MoEQ) with the objective to study the diversity of marine species in Qatar and has become an active partner in the Whale Shark Research Project ("QWSR") that was launched by MoEQ and David Robinson from Heriot-Watt University. The overall objective of QWSR is to provide a long term monitoring programme, which can provide a robust description of the whale shark population and marine ecology in Qatari waters. The activities conducted in 2012 included a two-week whale shark expedition with participation of international scientist. The results confirm that the whale sharks feed on the high concentration of zooplankton in the water. Satellite and acoustic transmitters where attached to the sharks to follow their movements. A better understanding of the hydrodynamics and food chains in the Arabian Gulf will add to the understanding of the population dynamics. The data will make it possible to take appropriate action in order to secure the protection of biodiversity in the Arabian Gulf.
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Optical and surface properties of anatase TiO2 by sol-gel for solar cells
المؤلفون: Najat AljufairiIntroduction: Solar energy has been one of the most active research areas in the last decade because it is environmental friendly with respect to conventional energy resources. Titanium dioxide (TiO2) is a promising oxide material that has useful electrical and optical properties. It has been extensively investigated for photovoltaic applications. Anatase titania (TiO2) is a well known n-type inorganic metal oxide semiconductor, it is transparent to visible light and has a high refractive index. TiO2 thin films have successfully been used in preparation of solar energy cells. Sol-gel is widely used because of its simplicity, commercial viability, and potential for cost effective mass production. It is also used for industrial fabrication because of its low-cost availability. Objectives: The effects of substrate types and thickness on structural, morphological and optical properties of dip-coated TiO2 thin films for applicability usage in solar cells were studied. Methods: TiO2 films have been prepared by sol-gel dip coating technique, using titanium isopropoxide (TIP) as precursors. The structure and the phase of TiO2 films were analyzed by x-ray diffraction which showed that films were anatase. Optical properties of the films were characterized by ultraviolet-visible spectroscopy and ellipsometry. Results: The optical band gap was calculated for anatase film layers 50, 100, 150 and 200nm at 3.95, 3.87, 3.75 and 3.70eV, respectively. The refractive index of the films were computed by ellipsometry which were in the range of 1.9 to 2.3 and a wavelength range from 380 to 600nm. The thickness of the films was obtained from ellipsometry as of 58nm per one dip. The surfaces of TiO2 thin films were analyzed by a scanning electron microscope (SEM), atomic force microscope (AFM) and energy dispersive spectrometer (EDS). The images obtained by SEM showed cracks and shrinkage particles in the film, whereas the images obtained by AFM showed a homogeneous distribution of elongated shapes of nanoparticles through the film. In addition, the composition of TiO2 thin films checked via EDS found a small amount of Ti. Conclusion: The results showed that anatase titania (TiO2) nanomaterials have a promised potential for applications in solar cells.
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Numerical modeling of thermal plume and residual chlorine fate in Qatar's coastal waters
المؤلفون: Eric Febbo, Venkat Kolluru and Shwet PrakashA 3-dimensional hydrodynamic model was developed and calibrated to simulate the thermal mixing zone and predict the fate of residual chlorine and chlorination by-products (CBP) from industrial cooling water discharged from Ras Laffan City. This model is novel since the individual and cumulative effects of cooling water discharges from several outfalls are estimated in a single simulation instead of requiring separate model runs for each outfall. The concept of incremental temperature rise (increase over the natural water temperature in the absence of outfall) was used to evaluate mixing zone plume dimensions. A probability-based computational methodology was developed to define the thermal plume mixing zone for the shallow coastal environment, which is influenced by strong tides and winds. A new boundary condition was introduced to address existing, ongoing and proposed breakwaters and structures without altering the model grid system while preserving the same boundary conditions for various management scenarios. In comparison to freshwaters, little is known about the formation of CBP in saline waters. Therefore, a comprehensive study was devised that included laboratory experiments to quantify the kinetics of residual chlorine loss and subsequent formation of CBP in seawater as well as extensive field data collection and testing of Arabian Gulf seawater samples for chlorine and CBP in the vicinity of the discharges. Equations to describe site-specific chlorine reactions were developed to replicate observations. This empirical approach takes into account the complexity of the reactions between organic precursors and chlorine, which usually involve several parallel pathways leading to a great variety of CBP formation products. This complexity makes it difficult to develop more generic models for simulating CBP formation. Analysis of lab and field data obtained in this study have enabled calibration of a site-specific numerical modeling tool that can be used to study transport and fate of various constituents in the coastal area.
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Nilpotence in physics: Generalized uncertainty principles and Tsallis entropy
المؤلفون: Nikolaos KalogeropoulosBackground and Objectives: The objective of this work is to illustrate concepts and applications of nilpotent structures in physics. To that end, we will use two examples, both of which have attracted considerable attention recently: the generalized uncertainty principle, in its various forms, and the Tsallis entropy. The former has been motivated and extensively used in string theory and black hole physics during the last two decades. There are almost 4000 papers written on the latter during the last 20 years, reflecting a considerable interest in Tsallis entropy as an alternative to the Boltzmann-Gibbs-Shannon (BGS) entropic form. The Tsallis entropy has been having a considerable impact in re-examining the foundations of statistical mechanics for both equilibrium and non-equilibrium processes. Nilpotent structures have a long presence in various branches of mathematics, especially in group theory and geometry with the works of Malcev and Gromov standing out as particularly pertinent for our purposes. We also consider the sub-Riemannian aspects of nilpotent structures which have applications in a variety of fields ranging from examining how a cat falls to analyzing human vision. Results: Both the generalized uncertainty principles and the Tsallis entropy indicate that the dynamical structure of spacetime and the statistical methods used to quantize it may benefit considerably if one uses general nilpotent structures instead of the two-stage Heisenberg model or the abelian group of the BGS entropy. Conclusions: Nilpotent structures are flexible enough to generalize aspects of quantum theory and statistical mechanics. At the same time, they are understood well enough to allow us to obtain results of potential physical significance. Hence they are worth taking a look at and exploring their consequences. Notes: Partial results have already been published by the author recently and have appeared in the arXiv.org repository and are being presented at various international conferences. Parts of this work were done in collaboration with A. J. Creaco of the City University of New York.
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Properties of nanoclay-PVA composite materials
المؤلفون: Mohamed Ali, Mohamoud M. Kahder and Khalid A. Al-SaadBackground: Polymer-clay nanocomposite (PCN) materials have become a focus of research due to their unique characteristics and potential commercial applications. Clay addition in polymers improves their properties and may result in better features. PCN materials are reported to have enhanced thermal, mechanical, flame retardation, corrosion protection characteristics. Objectives: This study investigates the effect of different loading concentrations of Na-rich montmorillonite (MMT) clay when they are effectively dispersed in a organic polyvinyl alcohol (PVA) matrix. Methods: PCN materials were prepared using the solution method. The structure morphology of the PCN was studied using x-ray diffraction (XRD) and NSEM. FTIR was applied to study the molecular structure of the PCN. The mechanical properties of the pure PVA and PCN were studied. The thermal stability of the PCN was studied using TGA and differential scanning calorimetry (DSC). Results: The morphological images and crystalline morphology indicated that PVA and MMT clay has intercalated by the uniform and homogenous dispersion and confinement of the PVA polymer chains within silicate layers of the clay. PCN XRD pattern has a high d-spacing compared to the pure MMT clay XRD pattern, which has a low d-spacing (Fig. 1). FTIR showed that as the loading of MMT clay increases, the intensities of the MMT clay bands become stronger in the FTIR spectra of PCN (Fig. 2). NSEM results showed that intercalation that took place between the PVA and MMT. It was found that the small amount of MMT clay made the tensile modulus and elongation percentage the PCN significantly higher than the pure PVA, due to polymer-clay intercalation. Thermal stability results showed that the PCN is more thermally stable than pure PVA. Conclusions: The excellent MMT nanoclay dispersion in PVA matrix leads to significantly enhanced mechanical properties, notably an increase in tensile moduli with significant increase in tensile strength, maximum load and percentage elongation of the PVA due to adding the small amount of MMT clay. The uniform and homogenous dispersion of MMT in PVA matrix results in an increase in thermal decomposition temperature and glass transition temperature of the promoted PVA polymer based on TGA (Fig. 3) and DSC (Fig. 4) results.
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New environmentally friendly polypropylene hybrid composites
المؤلفون: Mariam AlMaadeed, Nabil Madi, P. Noorunnisa Khanam and Ramazan KahramanRecycled polypropylene (RPP) based hybrid composites of date palm wood flour/glass fibre were prepared by different weight ratios of the two reinforcements. The mixing process was carried out in an extruder and samples were prepared by an injection molding machine. RPP properties were improved by reinforcing it by wood flour. Morphological studies indicated that glass fiber has good adhesion with RPP supporting the improvement of the mechanical properties of hybrid composites with glass fiber addition. An increase in wood particle content in the polypropylene resulted in a decrease in the degree of crystallinity of the polymer. The tensile strength of the composites increased with an increase in the percentage of crystallinity when adding the glass fibre. The improvement in the mechanical properties with the increase in crystallinity percentage (and with the decrease of the lamellar thicknesses) can be attributed to the constrained region between the lamellae because the agglomeration is absent in this case.
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Multifunctional hierarchical honeycombs
المؤلفون: Ramin Oftadeh, Babak Haghpanah, Abdel Magid Hamouda, Hamid Nayed-Hasemi and Ashkan VaziriBackground: In-plane properties (e.g. stiffness, strength and energy absorption) of two-dimensional cellular structures are generally far inferior to their out-of-plane properties. Therefore, cellular structures with modified morphology and organization, such as hierarchical and functionally graded structures with varying wall thickness or cell size have been developed to improve the in-plane mechanical response. Among these, hierarchical cellular structures have exhibited a range of promising and/or novel properties such as elevated specific stiffness or strength, negative Poisson's ratio, multi-stage dynamic crushing, and enhanced energy absorption under quasi-static loading. Objective: A hierarchical family of honeycomb-based cellular structures is formed by systematic introduction of successively smaller hexagons wherever three cell walls meet. This process can be repeated to obtain hierarchical honeycombs of different order. The objective of the current work is to provide analytical and finite element investigation to quantify the mechanical response and collapse of these structures. Method: The analytical analysis is based on an upper bound estimate from competing plastic hinge mechanisms defined for a representative unit cell of structure. Numerical and analytical investigations are carried out to investigate the range of attainable mechanical properties for hierarchical honeycombs by varying the order of hierarchy and/or geometrical parameters at each order. Results: Hierarchical honeycombs of first and second order can be up to 2.0 and 3.5 times stiffer than regular honeycombs at the same density. Moreover, the results show that there is no upper limit on the maximum achievable specific stiffness by further increasing the order of hierarchy for low densities of hierarchical honeycombs. In terms of plastic strength, hierarchical honeycomb with one order of hierarchy exhibit a maximum improvement of approximately 60% in specific strength. Conclusions: The results show that a wide range of stiffness and strength ratios can be obtained for hierarchical honeycombs by varying geometrical parameters. The current work provides insight into the role of structural organization and hierarchy in regulating the mechanical behavior of materials, and new opportunities for development of novel materials and structures with desirable and perhaps actively tailorable properties.
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Monitoring of biodegradation of BTEX in water using isotopes ratios
المؤلفون: Daniel Dessort and Hend HassanOrganic geochemistry plays a major role in the environmental assessments of water quality. Today, the tools used in exploration and production of hydrocarbons combined with good understanding on natural processes which form and alter the hydrocarbons during biodegradation, weathering, oxidation and evaporation, can be applied to predict the fate of pollution in water. BTEX (Benzene, Toluene, Ethylbenzene and Xylene) are very toxic compounds and are normally present in significant concentrations in petroleum. They are pollutants in groundwater and surface water due to their high solubility. Pollutant identification is usually conducted by specialised laboratories in order to determine the relationship between hydrocarbons in water samples and suspected source of pollution. Guidelines on recommended methods for sample collection, handling and analysis are well established. For instance, analysis of BTEX in headspace gas of water sample collected in closed vessels can be performed by using: *High-resolution gas chromatography (HRGC) *HRGC coupled with mass spectrometry (HRGC/MS) Beyond to the recommended methods, more advanced techniques can be used for the pollution assessment and its behaviour: *Solid phase micro extraction gas chromatography mass spectrometry (SPME-GCMS). This simple technique is able to sample and analyze 1 ppt only of benzene in water (1 ppt = 1 mg of benzene in 1000 m³ of water). This technique is very accurate and quantitative owing to the addition of known trace amount of internal standards. *Compound specific isotope analysis (CSIA). This sophisticated technique consists in measuring the carbon and hydrogen stable isotope ratios of individual compounds. The stable isotope ratio of individual components depends on their source and their alteration. In this paper, we will demonstrate state of the art technology to measure BTEX in waste water and its behavior during the natural biodegradation and weathering process. It was well demonstrated that biodegradation increases the concentration of ¹³C and ²H isotopes in the residual non-biodegraded hydrocarbons. This paper shows that the use of SPME-CSIA and SPME-GCMS enable us: *To monitor trace levels of BTEX. *To give evidence of the biodegradation of BTEX owing to their strong and specific isotope fractionation. *To calculate biodegradation rate of BTEX by using isotope fractionation.
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Mechanical, morphological and thermal properties of LDPE/glass, MDPE/glass and HDPE/glass fibre reinforced composites
المؤلفون: Mariam Al-Ali AlMa'adeed, Mabrouk Ouederni and PATAN NOORUNNISA KHANAMThree types of polyethylenes (low density: LDPE, medium density: MDPE, and high density: HDPE) were used to investigate the effect of chain branching on the dispersion and adhesion in glass fibre (GF) reinforced polymer composites. The compounding of LDPE/GF, MDPE/GF and HDPE/GF was carried out in a Brabender twin screw extruder. In each composite system, glass fibre was 20% weight and the main matrix was 80%. The mixtures were fed into hopper of the extruder, extruded, cooled and granulated. The compounded samples were prepared as test specimens by a PE 5 injection molding machine. Mechanical, morphological and thermal methods were used as the characterization techniques to study the interaction between the glass fibre and the polyethylene. Addition of glass fibres to the matrix enhanced the mechanical properties for all composite systems. The degree of enhancement, however, depended on the branching and crystallinity of each polymer. The long chain branching (LCB) in LDPE resulted in higher increase in modulus both in the melt and in the solid state. The higher crystallinity of HDPE was responsible for higher increase in tensile strength and less fibre pull-out upon addition of glass fibres. Scanning electron microscopy of LDPE/glass fibre reinforced composites showed more fibre pull out from the matrix. The addition of glass fibres also resulted in improved thermal stability of the various polyethylene samples. The main aim of this study was to understand the effect of the branching of polyethylene on adhesion of GF to the polymer chain and the results on mechanical, thermal properties of glass fibre reinforced composites.
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Mechanical performance of aluminum-silicon casting alloys for high-temperature applications
المؤلفون: Adel MohamedImproving the mechanical properties in an aluminum alloy at high temperatures should acknowledge several factors which are related principally to a decrease in the strength of the metal with increasing temperatures. Most applications of Al-Si casting alloys are generally used at temperatures of no more than 230°C. To improve the strength of the alloys under high temperature conditions, a microstructure containing thermally stable and coarsening resistant dispersoids is required. Nickel leads to the formation of Al3Ni and Al9FeNi in the presence of iron, while zirconium forms Al3Zri. These intermetallics improve the high temperature strength of Al-Si alloys, depending on the shape of the intermetallic particles, their volume fraction and the contiguity with the eutectic Si. The present work aims to investigate the effects of individual and combined additions of nickel and zirconium on the microstructure and strength of the cast Al-Si alloy, namely 354, at high temperatures. The cast alloys were given a solutionizing treatment followed by artificial aging at 190°C for 2 hr. High temperature tensile tests were conducted at various temperatures from 25°C to 300°C. Optical microscopy and electron probe micro-analyzer were used to study the microstructure of different intermetallic phases formed. The fractographic observations of fracture surface were analysed by SEM to understand the fracture mechanism. The results revealed that the intermetallics phases of (Al,Si)3(Zr,Ti), Al3CuNi and Al9NiFe are the main feature in the microstructures of alloys with Zr and Ni additions. The results also indicated that the tensile strength of alloy decreases with an increase in temperature. The combined addition of 0.2 wt% Zr and 0.2 wt% Ni leads to a 30% increase in the tensile properties at 300°C compared to the base alloy. Zr and Ni bearing phases played a vital role in the fracture mechanism of the alloys studied. Tensile strength of 354 alloy with additions of Ni and Zr are decreasing with increase of temperatures. The ultimate tensile strength and yield strength of alloys containing Ni- and Zr-bearing phases are higher than that of alloy for all testing temperatures.
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Identification of source of oil spills in the environment using biomarkers and isotopes
المؤلفون: Daniel Dessort and Hend HassanToday, the use of standard tools of petroleum organic geochemistry is the most convenient way to characterize and quantify contamination of environment by fossil fuel. Good knowledge of natural processes that alter the hydrocarbons during biodegradation, weathering, oxidation or simply evaporation, can also be applied to predict the fate of a pollution. For instance, organic geochemistry played an important role in the environmental assessments of oil spills (e.g.Exxon Waldez or Deep Water Horizon). Oil spill identification is usually conducted by a specialized laboratory in order to find the source of a spill. Guidelines on recommended methods for sample collection, handling and analysis are well established (e.g. NORDTEST Oil Spill Identification system). At TRCQ, we use a variety of geochemical techniques in order to: *make the distinction between naturally occurring hydrocarbons and anthropogenic pollution; *make the distinction between crude oil and refined hydrocarbons; *assess the origin of oil spills, oil slicks and gas seeps--these techniques can be used for the characterization of the origin of fluids in the case of well integrity issues; *monitor the fate of spilled oil and its alteration; *map the spatial distribution of hydrocarbon pollutants in sediments and aquifers and their evolution through time. Advanced geochemical techniques are used: *high resolution gas chromatography (HRGC) for fingerprinting; *HRGC coupled with mass spectrometry (HRGC/MS) for fossil biomarkers analysis; *compound specific isotope analysis (CSIA), a sophisticated technique that consists of measuring the carbon and hydrogen stable isotope ratios of individual compounds (C1 to C30) separated by GC; the stable isotope ratio of individual components depends on their source and their alteration, and CSIA is the only technique able to correlate the gas seep to its source. In this paper, we show the use of organic geochemistry to characterize the oil spill pollution at seabed occurring in 1998. GC-MS analyses of the alkane fractions has allowed delineating three groups of samples: *samples dominated by a petroleum signature; *samples in which petroleum occurs with a subordinate land-derived contribution; *samples in which petroleum is associated to a recent marine input--within this group one may generate a subgroup in which some terrestrial debris have been seen in minor amount.
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Hydrocarbon fuel-based hybrid fusion-fission nuclear reactor
المؤلفون: Abul hasanat Muhammad Jahanur RahmanNatural resources such as oil and gas can be used in more efficient ways. Instead of just burning these fuels, the exhaust gas or sync-gases can be used for hydrogen fusion reactions along with carbon fusion reactions. This offers the prospect of a longer-term supply of energy by using only a very small amount of fuel. Fusion reaction energy could be made relatively cheap by using proton tunneling catalytic reactors that bypass the nuclear repulsion barrier at lower temperatures, to produce enough energy that can be stored into hydrocarbons through Fischer-Tropsch synthetic gasification and pyrolysis cracking of CO₂. This could significantly decrease environmental pollution and the greenhouse effect. This catalytic reactor uses mesosphore support made of pyroelectric and piezoelectric crystals. Pyroelectric crystals convert the fusion temperature into electricity and piezoelectric crystals control the diameter of porosity to determine diffusion and fusion reaction rate. This active catalyst is a quasi-crystal of fullerenes covered by a single layer of graphene. By providing a voltage difference across this catalyst, its conductivity can be changed. By using magnetic field variable mass Dirac fermions (for example cooper electron-hole/phonon pairs), these can be introduced with different conductive layers (heterogeneous topological layers or parallel quantum wells) due to the quantum Hall effect. Hydrocarbons or its burned products enter this catalyst from mesophores through microphores by carrier fluids which need to be supercritical and superfluid with a momentum vortex at input temperature and pressure. Zero mass Dirac fermions are very sensitive to the applied field by piezoelectric crystal supports which produce maximum charge carriers compared to other layers where electron pairs have less mass. The higher the momentum of these ions, the higher the mass of the Dirac fermions (electron). At the collision point, the catalytic layer which has a Dirac fermion mass higher than the effective electron mass (such as the mass of the muon particle), this increases the probability of fusion by weakening the electron repulsion and increasing a strong nuclear force, also resulting in a tunneling effect due to an increase in gravitational pull between higher masses. This demonstrates that controlling resonance phonon frequency and the electric field through piezoelectric crystal fusion reaction can easily be controlled at lower temperatures due to the action of this catalyst.
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HAWA'AK: An end-to-end air quality monitoring system for Qatar
المؤلفون: Elias Yaacoub, Abdullah Kadri and Adnan Abu-DayyaThe effect of air pollution on human health is considered a major and serious problem, globally. The purpose of air quality monitoring is not merely to collect data but to provide the information required by scientists, policy-makers and planners to enable them to make informed decisions on managing and improving the environment, as well as to present useful information for public end-users. Monitoring fulfills a central role in this process, providing the necessary, sound scientific basis for developing policies and strategies, setting objectives, assessing compliance with targets and planning enforcement action. Traditionally, bulky air quality monitoring stations are used for collecting various gas concentrations. These stations include many reference analyzers. Although they have a high level of accuracy, such stations require frequent calibration and maintenance and they need access to power sockets mainly for air conditioning, which limits their use on a large scale. Research and industrial bodies are focusing on developing a new generation of sensing stations at a low cost, smaller size, and with more mobility features. Variations of such stations are being used in different indoor and outdoor environments for both residential and industrial applications. These sensor stations are generally deployed as a wireless sensor network (WSN). A WSN is composed of a number of sensing stations transmitting wirelessly the information they capture. A sensing station is generally composed of a power unit, processing unit, sensing unit, and communication unit. In this work, a real-time air quality monitoring system is presented. This system is based on utilizing multi-gas (MG) monitoring stations that communicate with a platform by means of machine-to-machine communication. Each MG monitoring station includes gaseous sensing elements, a data logging component, and a wireless communication board. They are powered by solar energy. The platform is located on a backend server where data cleaning and filtering operations are carried out. In addition, this platform converts the received data to useful information that is delivered to users through web portal and mobile applications. The system uses a high density of sensing stations per unit area in order to provide localized pollution information, as opposed to bulky analyzers deployed in limited numbers.
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Engineered wetland: A water treatment option
المؤلفون: Mohamad Yacob Al-SulaitiConstructed wetlands are engineered land treatment systems that utilize natural processes to improve water quality. A system that consists primarily of vegetation, aquatic organisms, soils and microbes is designed to assist in treating wastewater by taking advantage of the same process that occur in nature, but in a more controlled setting. Successful and sustainable planning and management of an engineered wetland (EWL) will be highly influenced by the degree of understanding of not only the natural processes that occur in the EWL, but many other equally important elements and how these elements work jointly. Engineered weland has an input--namely influent wastewater, treatment process--and an output effluent. The treatment process becomes more complete when the wastewater has many constituents, some of which may be specific to a certain industry or source. It is essential to ascertain a reliable characterization of water quality and quantity over temporal and spatial variations, and the impact of these elements will directly influence the design of the EWL. The treatment media of the EWL must be carefully selected to sustain itself to the subject conditions and support the targeted water treatment goals. These considerations will lead to an iterative process leading further to an engineered solution. This presentation will demonstrate the framework and scientific basis for the implementation of a research program currently underway at ExxonMobil Research Qatar to design and test a EWL according to local conditions.
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Breakthrough coastal research of Qatar as input to geological and reservoir modeling
المؤلفون: Christian Strohmenger and Jeremy JamesonMaximizing recovery in oil and gas fields relies on geological models that realistically portray the spatial complexity, composition, and properties of reservoir units. Present day arid climate coastal systems, like the coastline of Qatar provide analogues for depositional and diagenetic processes that control reservoir quality in ancient reservoirs. Many major reservoirs in Qatar are formed under conditions that are remarkably similar to those shaping the coastlines of today. Among the major controls on coastal sedimentation patterns are: 1) wind, wave and tidal energy, 2) coastline orientation, 3) relative sea level, 4) depositional relief and 5) sediment sources. Strong NW prevailing winds (shamal winds) drive shallow marine circulation patterns, creating four very distinct coastal profiles: windward, leeward, oblique, and protected. In addition, winds supply quartz sand to the leeward coast, as the dune fields of Khor Al-Adaid are blown into the sea. Elsewhere, carbonate sands are formed by wave breakdown of skeletal material in the shallow marine environment. These sands are washed ashore to form beaches. The grain size, composition, and dimensions of coastal sands vary due to wave energy. Coastal deposits are equally affected by high frequency oscillations in sea level. Approximately 8,000 years ago, the sea level was about 3 meters higher than it is currently and the Qatari coastline was up to 15 km inland. Most coastal deposits and sabkhas are relicts of this ancient highstand in sea level. Punctuated sea level drops to present day levels have led to the formation of seaward-stepping spit systems. Understanding these coastal and near coastal areas, the processes that form them, and developing geologic models based on this understanding, is a focus of the Qatar Center for Coastal Research (QCCR) within ExxonMobil Research Qatar. The observed spatial complexity and heterogeneity of modern coastal systems are important aspects to be considered for conditioning three-dimensional geological models. The studied modern outcrops along the Qatar coastline are particularly useful as analogs for conditioning subsurface data sets in geologic (static) and reservoir (dynamic) models.
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Green networks: Energy efficient design for future generations of wireless networks
المؤلفون: Muhammad Zeeshan Shakir and Khalid QaraqeBackground & Objectives: Qatar ranked number one in the world in terms of per capita CO2 emissions and is the latest Middle Eastern country to aggressively push towards reducing the per capita CO2 emissions and embrace a low carbon economy. Information and communication technology (ICT) already represents around 2% of total CO2 emissions (of which wireless networks represents about 0.2%) and this is expected to increase annually. The exponential growth in demand for higher data rates in wireless networks requires dense deployment of base stations which not only increases the energy consumption but also requires higher capital expenditures which still do not ensure an improvement in the data rate. To address the challenges of increasing the energy efficiency of the future wireless networks and maintain profitability, it is essential to consider various novel technologies which improve the energy efficiency of wireless networks and establish 'greener' networks. Therefore, decreasing the propagation distance between the base station and the mobile users is a promising solution to design energy aware wireless networks. Methods: Small cells such as femtocells are becoming a standard part of future wireless networks. We propose an energy aware design for wireless networks where the small cells are arranged around the edge of the macrocell such that the configuration is referred to as cell-on-edge (COE) where mobile users transmitting with a reduced transmitter power enjoy higher data rates due to shorter distances between the transmitter and the receiver. The COE configuration promises energy savings by integrating small cell and macrocell networks and thereby reducing CO2 emissions, operational and capital expenditures whilst enhancing the spectral and energy efficiency of wireless network. In this context, we define a performance metric which characterizes the aggregate energy savings per unit macrocell area and is referred to as an area green efficiency (AGE) wireless network. Results: The proposed wireless network design will provide a significant increase in energy efficiency of approximately 50% to 75% in comparison with the existing networks. Conclusions: The COE configuration has been shown to reduce CO2 emissions and thereby significantly improve the energy efficiency of future wireless networks.
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