Qatar Foundation Annual Research Forum Volume 2012 Issue 1

Background: Cobalt catalyzed Fischer-Tropsch synthesis (FTS) is a process for converting natural gas to liquid fuels. Supported cobalt catalysts are common for F-T reactions because of their high activity and selectivity for forming linear hydrocarbons. Oxide supporters affect the catalytic properties of cobalt significantly. Co and oxide support interact and lead to irreversible deactivation of the catalyst. Promoters, e.g., Pd, Ru and Pt are added to the cobalt oxide supported catalysts for various reasons, such as to increase the reducibility of Co and to act as a source for hydrogen spillover. Objectives: To investigate the oxidation isotherms of cobalt and cobalt supported oxide catalysts using coulometric titration (CT) and to examine the effect of the rhenium (Re) promoter on the reducibility of cobalt on an alumina catalyst. Methods: The sample was exposed to a gas mixture containing 10% H2, 3% H2O and 87% N2 for full reduction. The P(O2) was then established by equilibrium between H2 and H2O: P(O2)½ =K-1 * P(H2O)/P(H2) Oxygen was then pumped into the cell electrochemically by passing a current through the Pt electrodes (Fig. 1). The open-circuit potential across the electrodes (V) was measured in order to calculate P(O2) from the Nernst equation: V= RT/4F Ln PO2/0.21 Results: The oxidation isotherms obtained from the CT for reduced bulk cobalt oxide (Co3O4) (Fig. 2) and promoted catalyst (Fig. 3) exhibit two well-defined transitions. The first transition is corresponding to the oxidation of Co to CoO and the second oxidation is corresponding to CoO to Co3O4. On the other hand, the oxidation isotherms of reduced 15 wt% Co3O4/Al2O3 exhibit one transition, which is corresponding to CoO to Co3O4 (Fig. 4). It is clear that the Co/alumina compound has a limited degree of reduction, which may be due to the strong interaction between Co and alumina resulting in a non-reducible form of a Co-alumina compound (Figs. 5-7). This explains that rhenium enhanced the reduction of the cobalt/alumina catalyst to a metallic cobalt but it did not have an effect on the extent of reduction of the cobalt oxide Co3O4 to CoO. Conclusions: Coulometric titration and thermal gravimetric analysis results show that a rhenium promoter has facilitated the reduction of Co3O4 to Co (Fig. 8).

The development of clean energies is a central challenge for the sustainable development of the Gulf region. Global pressures including climate change mitigation efforts and energy security concerns are calling for strong investments in alternative sources of energy. Most of marine algae present in Qatar have no equivalents on earth and therefore could be considered as irreplaceable sources of primary and secondary metabolites. This is especially the case for hydrocolloids from red and brown algae that are cultured and used at an industrial scale for food-processing. This study analyzes the adaptability of existing biofuel production processes currently used for cooking oils or more traditional corn ethanol to algae fuel production. The potential benefits of biofuel from photosynthetic algae could be significant. Algae can be grown using land and water unsuitable for crop plant or food production, unlike some other first and second generation biofuel feedstocks. Moreover, select species of algae produce bio-oils through the natural process of photosynthesis - requiring sunlight, water and carbon dioxide, supplemented with nutrients. Growing algae therefore consume carbon dioxide, which provides greenhouse gas mitigation benefits. Finally, bio-oil produced by photosynthetic algae and the resultant biofuel will have molecular structures that are similar to the petroleum and refined products we use today. This helps ensure the fuels are compatible with existing transportation technology and infrastructure. In conclusion, if successful, bio-oils from photosynthetic algae could be used to manufacture a full range of fuels including gasoline, diesel fuel and jet fuel that meet the same specifications as today's products. This study bridges with a past survey carried out by Dr. Jean-Michel Kornprobst on the algae resources in Qatar and existing engineering processes currently developed in the United States and more specifically by the University of South Florida Polytechnic (Dr Philippidis) or the Abbess Ceter on Ecosystem Science and Policy at the University of Miami. Its objective is to assess the production capacity in Qatar as well as suggest projects and international cooperation to reach full potential.

Power generation through wind is expected to play a major role in the world's future energy portfolio. Wind power integration remains a challenging research area due to the unique characteristics of wind power generation. In particular, offshore wind has received significant attention worldwide due to the vast generation potential available. The electrical infrastructure of offshore wind farms is thus of significant importance. Multi-terminal high voltage direct current (HVDC) technology represents a preferable solution and has shown promise in solving wind farm interconnection problems. Droop control techniques have been proposed as a means to regulate the DC voltage and facilitate the automatic coordination between different converters without the need for fast communication between units. Different methodologies have been suggested to select the droop gains to satisfy the system performance specifications. In this work, a control design methodology is proposed for power sharing among the multi-terminal HVDC feeders providing that the power transmission efficiency is optimized. A simulation study on a 400 kV/1000 MW four-terminal HVDC transmission topology is conducted to determine the validity of the proposed methodology.

A user-friendly simulator based on a comprehensive computer model for slurry bubble column reactor (SBCR) developed in our laboratory was used to predict the performance of a conceptual commercial-scale (9-m ID and 50-m height) SBCR for indirect coal conversion using Fischer-Tropsch (F-T) synthesis in the presence of a cobalt catalyst. New correlations for predicting the hydrodynamic and mass transfer parameters and three different kinetic rate expressions from the available literature specifically for cobalt catalysts were incorporated in the simulator. The effects of operating conditions, including catalyst concentration, pressure, temperature, H2/CO ratio, and superficial gas velocity on the SBCR performance were predicted using the simulator. The predictions showed that the performance of the SBCR was strongly dependent on the kinetic rate expression used. At low catalyst concentration, the reactor operated in a kinetic-controlled regime with increased syngas conversion and catalyst productivity; however, increasing catalyst concentration drove the reactor to operate in a mass transfer-controlled regime with decreased syngas conversion and catalyst productivity. The transition from kinetic-controlled regime to mass transfer-controlled regime occurred at different solid concentrations depending on the kinetic rate expressions employed. High H2/CO ratios in the inlet feed gas to the SBCR led to high syngas conversion. Increasing the superficial syngas velocity in the reactor decreased the gas residence time, which decreased the syngas conversions. High operating temperature always resulted in high syngas conversion. Also, the effect of operating pressure on the SBCR performance was not clear, since increasing pressure resulted in low or high syngas conversion depending on the catalyst and kinetic rate expressions used.

Increase in energy demand and stringent emission standards drive the need for clean, alternative fuels. Gas-to-liquids (GTL), a liquid synthetic paraffinic kerosene (SPK) fuel obtained by Fischer-Tropsch synthesis has drawn global attention as an alternative aviation fuel due to its clean combustion characteristics when compared to conventional jet fuel. However, alternative fuels are expected to fulfill the key requirements such as having a quick atomization and vaporization and combustion and emission characteristics; similar to that of conventional fuels in order to qualify as a drop-in fuel in current aviation gas turbine engines. It is important to understand the atomization of these alternative fuels to better understand their combustion and emission characteristics. The key objective of this work is to evaluate the atomization characteristics of GTL-SPK which could potentially be used as a drop-in fuel in aircraft gas turbine engines in future. This work will discuss in detail the experimental facility developed, methodology and the results obtained using two GTL-SPKs having different chemical compositions. The spray characteristics such as droplet size and distribution are studied at three injection pressures using a pressure nozzle and compared to that of conventional Jet A-1 fuel. Results obtained clearly show that despite a considerable change in chemical composition, which in turn modestly altered the fluid properties among SPKs, the change in spray characteristics are found to be insignificant. This could be due to the minimal difference in fluid properties between the GTL-SPKs. In addition, the spray characteristics of the GTL-SPKs show close similarity to the spray characteristics of Jet A-1 fuel.

Qatar 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.

In 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.

Introduction: 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.

Background 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.

Recycled 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.

Organic 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.

Improving 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.

Natural 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.

Constructed 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.

Background & 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.

Microbial mats are only present under extreme conditions, where grazing by higher organisms is limited. Therefore, microbial mats may provide insight into extraterrestrial life, due to their adaptations to extreme temperatures, desiccation or salinity. They are faced with a diurnal cycle with variable length based on their location, which exposes them to extreme salinity conditions (i.e., water withdrawal and high evaporation). Cyanobacteria in the photic zone of a mat ecosystem supply the other microorganism with the required organic material to produce energy and grow. Subsequently, this will reproduce the nutrients needed by the phototrophs through elemental re-mineralization. In this work, we investigated the effect of water salinity that covers the microbial mat ecosystem of Umm Alhool sabkha, Qatar, regarding the most important processes within microbial mats: photosynthesis and sulfate reduction (SR). Our results showed that both photosynthetic and sulfate reduction rates decreased with increasing the salinity. The microbial community structure, assessed by 454 pyro-sequencing, revealed that the cyanobacterial community structure changed in response to the change in salinity. This was not the case for the sulfate reducer community structure, which stayed as it is in the mats incubated at different salinities. Therefore, we speculate that salinity affects the photosynthetic community structure, and consequently affects the photosynthetic activity of the whole ecosystem. However, sulfate reduction rates decreased due to less organic material supply from the upper layers and not due to change in microbial community structure of SR. Other factors such as the activity of the enzymes could also have an effect on SRR, but it was not investigated in this study.

The increasing use of lead-free solders is driven by the direct threat of strict legislation to ban the use of lead-based solders in electronics manufacturing industries by the USA, Japan and countries under the European Union. An additional driver is the market change due to public 'green awareness'. Therefore, establishing a lead-free solder has become a critical issue. In recent years, many attempts are made to develop high-performance, lead-free solders. Among the new lead-free solders, the Sn-3.5Ag, Sn-3.0Ag-0.5Cu and Sn-0.7Cu solders are the most promising alloys. However, these commercial solder alloys are more expensive and exhibit higher melting points when compared to the conventional Sn-37Pb solder alloy. Magnesium (Mg) is much cheaper than silver (Ag) and copper (Cu) and the eutectic/near eutectic temperature of Sn-Mg alloy is much lower than the lead-free Sn-Cu or Sn-Ag solders. Accordingly, in the present study, new lead-free Sn-2.5Mg solder was developed incorporating 2.5 wt. % Mg into pure tin using disintegrated melt deposition technique. Solder samples were then subsequently extruded at room temperature and characterized. Microstructural characterization studies revealed equiaxed grain morphology, minimal porosity and relatively uniform distribution of secondary phase. Better coefficient of thermal expansion was observed for a Sn-2.5Mg sample (23.1 x10-6/K) when compared to conventional Sn-37Pb solder (25 x 10-6/K) or lead-free Sn-0.7Cu solder (30 x 10-6/K). A melting temperature of Sn-2.5Mg was found to be 219 0C which is much lower than the conventional Sn-Ag-Cu or Sn-Cu (227 0C) solders. Microhardness was increased by 271% with the addition of Mg into pure tin. Room temperature tensile test results revealed that the newly developed Sn-Mg solder exhibited enhanced strengths (0.2 % yield strength and ultimate tensile strength) with comparable (if not better) ductility when compared to other commercially available, and widely used, Sn-based solder alloys.

This paper investigates for the first time the effect of the amount of Maleic anhydride (MA) on blends of recycled polymers and date palm fibre composites. Recycled low density polyethylene (RLDPE) 20 wt%, recycled high density polyethylene (RHDPE) 40 wt%, and recycled polypropylene (RPP) 40 wt%, blends have been prepared. The recycled polymers, 10 wt% RLDPE, 35 wt% RHDPE and 35 wt% RPP, were used as the polymer matrix for preparing the composites with 20 wt% date palm fibre leaves and 1,2 wt% of MA. The composites were prepared by a two-step process, extrusion followed by injection molding. The results showed that the addition of MA by 1 wt% has the maximum effect in improving the tensile strength and tensile modulus of the material but reduced the hardness. Pure blend matrix showed higher % of elongation at break and hardness. Melting and crystallization points of the blends did not change with the addition of the fibre and MA, but an improvement in the thermal stability by 4 °C was achieved for the 1 wt% of MA composite compared to the composite without the MA, which is confirmed by the improvement in bonding between the blend matrix and the date palm fibre shown in the scanning electron microscope morphology photos.

Most global energy comes from fossil fuel. Currently, there is a strong belief that climate change is anthropogenic and attributed to fossil fuel consumption. Heating and cooling systems account for half of global energy consumptions. In hot and underdeveloped countries such as Qatar, the share of air conditioning systems is expected to be even more than half the national energy consumption. This provides the challenge to study energy consumption in building sectors to find new methods to increase the performance of air conditioning systems. Up until now, renewable energy sources supply only around 2-3% of the annual global heating and cooling demand. Due to its high thermal performance, heat pump systems and in particular ground coupled heat pump systems (GCHP), are increasingly becoming more common for air conditioning applications. In the light of the improvement in performance of photovoltaic systems, the combination between the photovoltaic and HP or GCHP is gaining more economic feasibility. This paper studies renewable energy options for building cooling systems for energy and environment savings. To achieve this goal, a residential apartment in Doha, Qatar, was selected as a case study. The cooling demand of the case study was assessed and four different cooling systems were designed including: (1) air coupled heat pump system (as a reference system); (2) ground coupled heat pump; (3) air coupled heat pump combined with a photovoltaic panel to generate electricity; and (4) ground coupled heat pump combined with a photovoltaic panel to generate electricity. Compared to the reference system, the reduction in the non-renewable energy consumption and the payback time was estimated for each system.

The evolution of coastal plains, the present day shape, and surface hydrology of Qatar are related to changes in relative sea level. Several factors acting on different time scales have contributed to sea level changes. These include tectonism and glacioeustasy. The peninsula shape is the surface expression of the Qatar Arch, one of the largest structural features of the Arabian Plate. It plunges northward into the Zagros foredeep. The Arabian Gulf initially formed during the Tertiary period as a foreland basin due to the uplift of the Zagros Mountains. Previous studies indicate the Arabian Gulf was an arid fluvial plain during the Last Glacial Maximum, 18,000 years before present (BP). The Gulf floor was a likely route for people migrating between Iran and Arabia. 14,000 years BP the sea level started rising, flooding the Gulf. The period between 14,000-7000 years BP was marked by a rapid rise (1 m/100 yr) driven by the melting of the polar ice caps. Age dating of Qatar coastal deposits indicate the rate of rise decreased as the sea level approached present day, 7000 years BP. Most coastal deposits are relicts of a Holocene sea-level highstand, dating from 7000-3000 years BP. Holocene beaches at 2-4 meter elevations and up to 15 km inland are relicts of this highstand. Similar beaches are found elsewhere along the Gulf. During this period coral reefs formed a discontinuous fringe around the windward and oblique Qatar coastlines. A drop of sea level approximately 2000 years BP may account for the demise of the fringing reefs. The occurrence of Late Pleistocene to Miocene fluvial gravel deposits of the Hofuf Formation 20 to 40 meters above sea level are interpreted as being related to long-term tectonic uplift, the evolution of the Zagros foredeep and structural tilting of the Arabian plate. Pleistocene shoreline deposits above present sea level dating from 30,000-40,000 years BP are interpreted as part of the same structural flexural event. Thus, data from Pleistocene to present suggest that the sea-level history of Qatar reflects relatively high frequency changes driven by eustasy superimposed on a long-term pattern of tectonic uplift.

Background and Objectives: Stress concentration around cavities and cracks strongly influence the fracture and fatigue properties of porous materials. Microcracks that form around discontinuities in the material such as cavities link up to form macrocracks leading to substantial degradation of material mechanical properties. The dominant factor aiding the formation of microcracks is the stress concentration. The study investigates the dynamic stress concentration around different size oblate spheroidal cavities due to shear waves in an infinite elastic medium. Methods: As the available analytical methods are only applicable to simple shape cavities, hybrid methods have been presented to study the stress concentration around different shape cavities embedded in an elastic medium. The method used combines the finite element method with analytical procedure for elastic wave propagation in an elastic medium. The accuracy of the method was verified by analyzing a spherical cavity. Results: Different shape oblate cavities are investigated under varying frequencies of shear waves and different matrix material properties. The stress concentrations within the matrix are found to be dependent on the frequency of incident shear wave, aspect ratio of the cavity and the Poisson's ratio of the matrix. Conclusions: The study reveals that the dynamic stress concentration can reach much higher values than the static case. Dynamic stress concentration factors as high as 6 result for low aspect ratio cavities of 0.2 and even values of 6.6 with a materials Poisson's ratio of 0.45.

Barchan dunes in southeastern Qatar are relentlessly pushed by northwesterly, shamal, winds. This research aims to understand whether a synergy between moisture retention and microbial growth could be exploited to stop them from upsetting natural habitat as they pass. These mobile dunes in Qatar also constitute a unique test area in which to study mechanisms of desertification. After characterizing the behavior and shape of the dune field west of Umm Said, we developed unique instruments for detecting humidity in hyper-arid environments. Using those, we measured diurnal variations in temperature and humidity beneath the dune, as well as fluxes of carbon dioxide through the surface. We also recorded temperature and humidity from a probe initially buried on the dune's avalanche face, emerging 15 months later on its windward face. In the laboratory, we measured effective diffusion, permeability and activity of its sands. By inserting an artificial rippled porous surface in our wind tunnel, we recorded how winds can induce a flow of air within porous sands, thus facilitating moisture and dust intake. Metagenomic analysis of DNA extracted from two dunes revealed that the dune microbial communities were dominated by bacteria from the actinobacteria and firmicutes phyla. Consistent with the known metabolic capacity of these phyla, in silico assessment of the metabolic potential of the dune microbial community suggests that is dominated by heterotrophic bacteria, with surprising few genes for photosynthesis being detected. Other genes, however, were detected that may prove useful in dune stabilization efforts such as urease, and in biotechnology applications such as antibiotic biosynthesis. We succeeded in adapting cultivation independent methods for quantifying viable microbes directly from the sand and in culturing microbes found on individual sand grains. Analysis of the metabolic potential of these isolates is ongoing.

Background & Objectives: Heat wave hazard modelling is attracting a lot of attention, especially with the onset of climate change and global warming currently taking place. General global climatic models and trends predict that heat waves will increase in frequency, duration, and intensity. Yet, heat wave hazard modelling remains a challenging and imperative problem because of the complexity introduced by natural and human elements such as land-use, air temperature variability, topography, soils characteristics, and air pollution. In this study, heat wave hazard in Qatar is mapped, modelled and predicted for two and five years. Methods: Geographic information system (GIS) and remote sensing (RS) techniques are used to carry out multilayer analysis by combining different parameters that influence and determine heat wave in the region. Land surface temperature (LST) derived from remotely sensed data (Landsat ETM thermal infra-red band) is also used in the analysis. The LST image proved to be extremely useful as the variation of the thermal phenomenon is highly related to and reflects the land surface variability in the study area. Heat wave index (HWI) is calculated using in situ and Gumbel frequency analysis is used for head wave (HW) prediction. Step-wise regression analysis is used to identify the predictive variables/parameters of HWI and to determine the model. Results: The magnitude and spatial distribution of heat wave in Qatar are mapped. These results can be used address environmental, health, and urban planning issues. Population-census data is used to estimate the proportion of the vulnerable age groups that will be affected by HW in Qatar. More than 87% of children aged 4 and less are found to be at very high risk to HW, while more than 86% of people above 65 years are at the same level of risk. Conclusions: GIS and RS techniques are valuable research tools for environmental studies. The model developed here can be used by decision makers and planners to make better informed decisions on planning of hospitals and schools in low heat wave risk areas. Furthermore, the model gives a good indication for planning future electric energy consumption by air-conditioning and cooling of buildings.

The concentration of CO2 in the atmosphere keeps increasing, relentlessly approaching the critical threshold identified as a point of no return for global warming. Recent research on carbon sequestration revealed that emission reduction targets would be hard to achieve with a single solution, namely underground storage, since a great deal of issues are still outstanding. To name but a few of these, one can cite a legal framework, international cooperation and availability of underground storage sites of sufficient quality and capacity. The nature of the outstanding issues is truly global, requiring a global approach for carbon management. Work supported by QNRF addressed important aspects of carbon management and constitutes the basis for the work presented herein. The objectives of this work include a balanced analysis of CO2 mitigation methods currently being tested or still under development, and the best way forward to break the cycle of undecisiveness currently being adopetd by most nations. The topics covered include carbon capture, underground storage in both depleted reservoirs and saline aquifers, carbon conversion, energy efficiency and development of carbon sinks on a global scale. The work has shown so far that the bulk of man made carbon emissions arise from combustion processes, essentially power generation using fossil fuels, and this is relatively well documented by the international energy agency compared to other sources of emissions. The cost of capturing combustion CO2 constitutes the bulk of the composite cost of carbon capture, storage and utilization (CCSU). Once CO2 is captured, it has to be disposed of where facilities are available. In the absence of suitable storage sites, other forms of carbon emission reduction have been identified and would include energy efficiency, carbon conversion and mandatory carbon sinks. The work has shown that it is practically impossible to expect all nations emitting CO2 to employ CCS only. The work achieved is of great significance in highlithing the complexity of carbon management on a global scale and offers alternatives that are both technically feasible and economically balanced.

Background: Existing technologies for detecting gas releases in oil and gas facilities include point and path detectors and leak detection and repair (LDAR) programs. Large networked arrays of point and path detectors are needed to detect gas leaks in oil and gas facilities due the inherent passive nature of these stationary technologies that require gas plume to come in contact with or within the line of sight the detectors. LDAR programs are not fully automated and require surveying millions of nodes in given plant to detect possible leaks. A potential solution to these challenges is a remote gas detection tools that could actively search for and autonomously detect gas leaks while removing the human component from the equation. Objectives: ExxonMobil Research Qatar is undertaking research to develop a Remote Gas Detection (RGD) system that will autonomously scan for and identify hydrocarbon gas leaks / emissions on a continuous basis. The system utilizes existing infrared (IR) detection technologies and expands its use to techniques that do not require human involvement. Prompt, efficient detection of gas leaks could significantly reduce fugitive emissions to the environment and provide early warning to operations personnel improving safety. Results: This research effort has led to the development of a sophisticated RGD system that is equipped with artificially intelligent software algorithms that can distinguish hydrocarbons from other IR hotspots in the scene with minimal false alarms. Early research activities included testing multiple RGD prototypes that integrated different IR camera technologies paired with various types of deployment strategies. Successful field tests were performed in late 2011 and led to the initiation of a short-term prototype field deployment in early 2012. Extensive libraries of IR videos, that highlight the behavior of the intelligent algorithm and the efficiency of the detection capability in varying environments, have been developed. This research effort has yielded two patent applications for novel and innovative developments in the field of remote gas detection. Future work includes evaluating system components and optics to facilitate efficient development of the first fully operational system, and continuation / expansion of the scope of pilot projects for long-term field testing.