bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of greywater treatment in a submerged membrane sequencing batch reactor
Authors: Abu Reesh Ibrahim Mohamad , Gildemeister Rene , Kraume Matthias
Published: October 2012

A simplified mathematical model was developed to describe the performance of a submerged membrane sequencing batch reactor for the treatment of synthetic greywater. The greywater was characterised by low soluble carbon and relatively high nitrogen content. The developed mathematical model describes volatile suspended solids (VSS), chemical oxygen demand (COD), dissolved oxygen (DO) , NH₃, NO₂, and NO₃ concentrations with time using a total cycle time of 240 min (60 min for the anoxic and 180 min for the aerated phase). The obtained differential equations were solved using the Matlab function "ode 45". This solver is used for solution of initial value problems. The kinetics and stoichiometric parameters were determined for this type of wastewater. The theoretical predictions obtained from the kinetic model were compared with the experimental results and a good correlation was observed. In this study, the submerged membrane sequencing batch reactor was successfully used for carbon removal from greywater, and showed optimization potential for the nitrogen removal.
Spray characterization of gas-to-liquid alternative aviation fuels
Authors: Kannaiyan Kumaran , SADR REZA
Published: October 2012

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.
Self-cleaning performance of polyvinylidene fluoride-zinc oxide composite coatings for civil and industrial applications
Authors: Mohamed Adel
Published: October 2012

Synthesis 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.
Remote sensing research project: Satellite imagery evaluation for environmental classification in Qatar
Authors: Febbo Eric , Richard Cecile
Published: October 2012

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.
Whale shark aggregations and biodiversity in the Arabian Gulf - an example of research collaboration between authorities, research institutions and the oil industry in Qatar
Authors: Bach Steffen Sanvig , Al-Jaidah Mohammed
Published: October 2012

Al 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.
Properties of nanoclay-PVA composite materials
Authors: Ali Mohamed , Kahder Mohamoud M. , Al-Saad Khalid A.
Published: October 2012

Background:
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.
Multifunctional hierarchical honeycombs
Authors: Oftadeh Ramin , Haghpanah Babak , Hamouda Abdel Magid , Nayed-Hasemi Hamid , Vaziri Ashkan
Published: October 2012

Background:
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.
Monitoring of biodegradation of BTEX in water using isotopes ratios
Authors: Dessort Daniel , Hassan Hend
Published: October 2012

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.
Mechanical, morphological and thermal properties of LDPE/glass, MDPE/glass and HDPE/glass fibre reinforced composites
Authors: AlMa'adeed Mariam Al-Ali , Ouederni Mabrouk , NOORUNNISA KHANAM PATAN
Published: October 2012

Three 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.
Mechanical performance of aluminum-silicon casting alloys for high-temperature applications
Authors: Mohamed Adel
Published: October 2012

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.
Engineered wetland: A water treatment option
Authors: Al-Sulaiti Mohamad Yacob
Published: October 2012

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.
Breakthrough coastal research of Qatar as input to geological and reservoir modeling
Authors: Strohmenger Christian , Jameson Jeremy
Published: October 2012

Maximizing 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.
Electric properties and surface structure of titanium dioxide for solar cells
Authors: Aljufairi Najat
Published: October 2012

Background:
Titanium dioxide (TiO2) films have been extensively studied due to their interesting electrical and optical properties. They have the potential to be used for a number of electronic device applications such as dye sensitized photovoltaic cells and also anti-reflective coatings, gas sensors, electrochromic displays and planer wave guides.

Objective:
Measurement of the electric properties and surface structure analysis of TiO2 thin films was investigated for the purpose of solar cell applications.

Methods:
Different characterization methods were used to determine the quality of the film. The surface morphology was characterized by a Philips XL40 scanning electron microscope (SEM) and atomic force microscope (AFM). X-ray diffraction (XRD) data was collected on a diffractometer using CuKa radiation at a wavelength of 1.5406 Å at 40 kV and 30 mA to assess the structure of the deposited films. The homogeneity and contaminants of the TiO2 composition were analyzed by energy-dispersive spectroscopy (EDS).

Results:
Titanium oxide thin films deposited on substrates by the sol-gel dip-coating technique were produced under different conditions. The current voltage (I-V) properties of TiO2 were measured in different temperatures ranging from 80 to 400 K, using a digital Keithley 6571A electrometer. The I-V characteristics appeared to be ohmic at a low voltage and space charge limited (SCL) at a higher voltage. The activation energy of TiO2 was also calculated, yielding one of two values, depending on the temperature regime. The conductivity increased when the grain boundary effect was reduced as the particle increased in size. The morphology of the films were analyzed by AFM, which revealed that the films were uniform, homogeneous and smooth and also that nanoparticles were present. The structure and the phase of TiO2, analyzed by XRD, showed that the films were anatase. In addition, the composition of the TiO2 thin films studied via EDS showed they were rich in Ti. The thickness of the films were obtained from ellipsometry based on the Cauchy function, which gave a figure of 58 nm per dip.

Conclusion:
This analysis showed that anatase titania nanofilms (TiO2) have a great potential for application in photovoltaic devices.
Numerical analysis of the ship motion exerted by interior sloshing on the LNG carriers
Authors: Hamouda A.M.S. , Xu Gang
Published: October 2012

Liquefied natural gas (LNG) carriers have played and will continue to play a key role in ocean gas transportation with the increasing demand for energy. Safe operation of LNG carriers requires the knowledge of global and local fluid pressures imposed by the sloshing liquid. As LNG carriers are required to operate in different environmental conditions, safety is a primary consideration in such operations. LNG carriers are often subjected to significant sloshing loads during their operational life. The motion of the LNG carriers as they move across oceans cause the liquid in the containers to slosh. Liquid sloshing may cause large internal stress and deformation in the walls of containers, particularly when the external forcing frequency of the ship is close to that of the natural sloshing frequencies. This effect is a critical consideration in ship design. The objective of this work is to find an effective numerical model solving the coupled internal sloshing and external seakeeping interaction for small/medium LNG carriers. To assess the influence of the liquid motion in tanks on the overall body behavior, a three-dimensional method for dynamic coupling between liquid motion in ship tanks (sloshing) and rigid body motions of ships (seakeeping) in the frequency domain, is considered. The method is formulated under the classical assumptions of linear potential theory and boundary integral equation methods, which are used to solve both interior sloshing and exterior seakeeping. Two tank LNG carriers have been analyzed and the typical coupling effects (two peaks) of the sway and roll transverse motions in the beam have been presented. This method produces quick and reliable results of ship motions.
Development of new lead-free Sn-2.5Mg solder for electronic packaging industries
Authors: Alam Md Ershadul , Gupta Manoj , Hamouda AbdelMagid Salem
Published: October 2012

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.
Assessment of thermal performances of nanofluids in industrial type heat exchangers
Authors: Cox Jonathan , Kanjirakat Anoop , Sadr Reza
Published: October 2012

Application of nanotechnology in industrial applications is receiving increased attention this century. Nanotechnology could be used to improve performances of heat exchangers, which are widely used in industrial applications by augmenting heat transfer characteristics of working fluids. Nanofluids, which are engineered colloidal suspensions consisting of nano-sized particles (less than 100 nm) dispersed in a base fluid, have shown potential as industrial cooling fluids mainly due to enhanced heat transfer characteristics. The present work examines the heat transfer performances of different industrial type heat exchangers using nanofluids. Experiments are conducted to compare the overall heat transfer coefficient and pressure drops of water vs. nanofluids in shell and tubes, and plate type heat exchangers on a laboratory scale. SiO2-water nanofluids prepared by dispersing 20 nm diameter nanoparticles at three different particle mass concentrations of 2%, 4% and 6% are used as the working fluid. The nanofluid is maintained in the cold loop of the circuit to avoid direct particle deposition on heater surfaces, and tap water is circulated in the hot loop. The experimental results show a consistent increase in the total heat transfer coefficient of the heat exchanger for the nanofluid concentrations tested. However, the pressure drop in the nanofluids flowline is observed to have increased in comparison to that of the base fluid, which can limit the applicability of nanofluids in heat exchangers.
Turbulent characteristics of atmospheric surface layer in Qatar
Authors: Sadr Reza
Published: October 2012

Wind power is one of the world's fastest growing renewable energy sources. Design and performance of wind turbines greatly depend on the atmospheric turbulence on the plant site. Furthermore, turbulent characteristics of the atmospheric boundary layer are of utmost importance in modeling the large-scale meteorological processes, diffusion of atmospheric contaminants, heat transfer and evaporation off of the earth's surface. Meteorological data are available for some areas of the globe but are sparse in tropical regions. There had been some recent studies in tropical weather in southwestern Asia but no data is available for the Gulf region. The present study for the first time reports the micrometeorological data collected from an atmospheric measurement station in the coastal region of Doha, Qatar, to characterize the nature of atmosphere surface layer (ASL) and ocean wave in this region. In the present work, turbulence velocity spectra and stability in Qatar is presented and compared with the available data from other locations. Also, empirical relationship for the normalized dissipation function in this region is suggested. Finally, variation of different length scales with the stability parameter z/L is investigated and compare with the existing values in available literatures. This is the first ever study of ASL in this area, and is expected to be a foundation of further atmospheric research endeavors in Qatar.
Advanced training tools for oil and gas industry personnel
Authors: Abdel-Moati Hazem Mohamed
Published: October 2012

Background:
The pool of experienced oil, gas and chemical plant operators, mechanics and other plant personnel is not keeping pace with demand in active oil and gas hubs like in the State of Qatar. Many individuals new to the oil and gas and related industries are being hired. A premium is being placed on getting these individuals quickly trained and qualified to assume increasing job responsibilities. This places great pressure on training functions within existing production units. A solution to this challenge is to develop advanced training tools that could be specifically used in oil, gas and chemical plants.

Objectives:
This research effort, undertaken by ExxonMobil Research Qatar, aims to develop immersive 3D training simulators for training of personnel in oil and gas production, processing, and transportation facilities. Realistic training scenarios developed for simulators range from routine operations, to developing competencies and assuring operational excellence responding to high consequence/low probability events.

Results:
This research effort led to the development of 3D visualization platforms for use in training process operators and young engineers joining the workforce. The platform supports the development of small-scale 3D immersive training simulators that combine dynamic process simulators with fully functioning and interactive 3D models. 3D models include compressor skids, re-liquefaction plants and other small-scale processing units. Extensive libraries of 3D models for process equipment, instrumentation, piping and field structures were developed and leveraged to promote efficiency when developing further 3D models. The platform is designed for multiple field operators training simultaneously through connectivity with other 3D display systems. Ongoing software and hardware upgrades have enhanced performance, widened applicability and allow for more complex and ultradetailed 3D models. Work is ongoing to develop a full-scale training simulator of an actual LNG facility process unit located in the State of Qatar. Augmented reality work-aids, for procedure verification in the field, have been developed for training and competency assessment. The research effort yielded a patent application for novel and innovative developments in the field of 3D immersive simulators. Future work includes learning management systems to track progress and scoring for trainees and further enhancement of realism in 3D environments.
A case study on nutritional myopathies of young camel in Qatar (Camelus dromedaries) and (Camelus bactrianus) from 0 - 3 months old of age".
Authors: Cruz Luningning Mariano
Published: October 2012

This study was conducted over 45 days, on a total of 25 sample animals. It targeted the nutritional myopathies of camels, born and bred in Qatar, ranging in age from zero to three months. Blood and fecal samples of young were collected to identify the quality of commercially-used starter feeds and conventional feeds. Commercially manufactured silage stored and produced within the municipality is available for herdsmen to purchase as replacement feeds for adult lactating dam. Further study will target the use of milk replacement among nursing animals due to dam with low milk output in order to prevent young animals from incurring further degenerative diseases. Randomized samples will be collected.
DFT performance in the activation of molecular hydrogen by gold and silver
Authors: Moncho Escriva Salvador , Brothers Edward N. , Janesko Benjamin G.
Published: October 2012

Heterogeneous catalysts are a critical part of industrial chemistry, primarily as a tool for more economically and ecologically efficient chemical processes. It is thus desirable to develop theoretical methods that can predict trends in catalytic activity and predict active catalyst for industrially important reactions. We have chosen to undertake a benchmarking study of various methods on the dissociation of molecular hydrogen on small gold and silver clusters. The simulation of the reactivity of H2 over small noble metal clusters is interesting both for elucidating the participation of the small clusters and also as a model for the metal-hydrogen interactions in nanoparticles and surfaces.

In this study, the mechanism of the dissociation of H2 on Au3 and Ag3 clusters is computed with a high-level of theory, namely CCSD(T)/CBS. Several transition states and isomers with two independent H atoms coordinated to a triatomic cluster have been found.

A benchmark study of the performance of DFT methods for the calculation of these mechanisms was perfomed. A wide range of DFT functionals have been selected for this work including a local functional; semi-local functionals; hybrid functionals; range separated hybrid functionals; double-hybrids including the HF-like exchange and MP2-like correlation; and new developed Rung 3.5 functionals including both the exact and semi-local one-particle density matrices. Wave function methods are also included for comparison purposes.
First record of Meloe coelatus Reiche, 1857 (Coleoptera: Meloidae) for Qatar
Authors: García Paris Mario , Ruiz Jose Luis , Castilla Aurora , Mohtar Rabi
Published: October 2012

Blister beetles of the genus Meloe Linnaeus, 1758, are widely distributed in temperate areas. However, their presence in arid environments is often overlooked. This is certainly true for Qatar. According to the Catalogue of Palaearctic Coleoptera (Bologna in Löbl & Smetana, 2008) there is not a single record for the genus Meloe in Qatar, although the genus is well represented in other areas of the Arabian Peninsula.
Meloe coelatus is a rare species, infrequently found, distributed in a wide area of Northern Africa (from the Canary Islands to Tunisia) and in Western Asia (from Sinai Peninsula to Iran). Most of the reports correspond to isolated data; therefore, there are no records for many countries where the species might be present. We report here the discovery of a population of Meloe coelatus in northern Qatar that bridges the current geographic gap in the known distribution of the species, from Saudi Arabia to Iran. These findings suggest that the blister beetle (Coleoptera of the family Meloidae) fauna of Qatar, might be underestimated. A thorough field survey is recommended in order to document the presence of other species of this family, which was considered of medical relevance in past times.
Study of the redox properties of Co3O4/SiO2 catalysts
Authors: Ali Mohamed , Khader Mahmoud
Published: October 2012

Background:
Cobalt catalysts are employed in catalyzing several important and selective reactions, one of which is the Fischer-Tropsch (F-T) reaction that is becoming of particular importance because of its application in converting natural gas and coal into liquid fuels. Supported cobalt catalysts are used most commonly for F-T reactions because of their high activity, high selectivity for forming linear hydrocarbons, low activity for the water gas shift reaction and lower cost compared to noble metal catalysts. In these reactions, cobalt is supported on an silica oxide material.

Objectives:
To investigate the oxidation isotherms of 15 wt% Co3O4/SiO2 using the coulometric titration (CT) technique and to study the effect of the reduction gas type on the Co3O4/SiO2 isotherm.

Methods:
The sample to be analysed was placed in an alumina crucible that was then inserted into the centre of the YSZ tube (Fig.1). The sample was exposed to a gas mixture of H2-H2O for full reduction. Reduction also was carried out using a mixture of CO-CO2. The P(O2) was then established by equilibrium between H2 and H2O:

P(O2)½ =K-1 * P(H2O)/P(H2)

Oxygen was then pumped into the cell electrochemically by passing a current through the Pt electrodes (Fig. 1). The open-circuit potential across the electrodes (V) was measured in order to calculate P(O2) from the Nernst equation:

V= RT/4F Ln PO2/0.21

Results:
The oxidation isotherms obtained from CT for reduced 15 wt% Co3O4/SiO2 (Fig. 2) exhibit two well-defined transitions. The first transition corresponds to the oxidation of Co to CoO and the second oxidation corresponds to CoO to Co3O4. Figure 3 represents the comparison of the Co/SiO2 oxidation isotherms at 873 K due to reduction using a mixture of H2/H2O and CO/CO2. The results indicate that the isotherms exhibit the same pattern but they are different in their P(O2) values. The transitions due to CO/CO2 reduction appear at lower P(O2) values.

Conclusions:
Coulometric titration results show that 15 wt% Co3O4/SiO2 exhibit two well-defined steps due to Co3O4/SiO2 full reduction. This indicates that there is no strong interaction between Co and silica.
Healthy homes: Towards a rational approach to houshold pests management in Rayyan Municipality, Qatar
Authors: Farrag Hassan , Abdalla Abdalla Hassan , Al Shamry Megbel Madhoor
Published: October 2012

Background:
Traditionally, household pest control relies entirely on the use of pesticides. Multiple hazards are associated with the use of pesticides.

Objectives of the study:
Because of the potential health effects of pesticides exposure, the main aim of this study is to seek alternative methods to control cockroaches. Management measures that keep unwanted pests out buildings and houses can control cockroaches and their associated allergens better than traditional pesticides spraying.

Methods:
Three methods of investigations were used: interviews with house owners, estimation of cockroach density by using sticky traps and direct observations on the habitat. Although the study was conducted mainly in Rayyan municipality but information on cockroach population density were also collected from other municipalities in Qatar.

Results:
Two species of cockroaches were identified. The American cockroach (Periplaneta americana L.) and the German cockroach (Blattela germanica L.). Sewage water manholes were the preferred locations for the American cockroach while the German cockroaches were found mainly in kitchens. Houses which were connected to the sewage water disposal nets suffered less from cockroach infestations. Clean houses that sanitary measures are less subjected to cockroach infestations.
Regular house repairs and maintenance are negatively correlated with cockroach density.
Houses with many entries suffer more from cockroaches. Number of residence in the house are positively correlated with cockroach density. Education level and awareness of the house owner is negatively correlated with the cockroach density. The use of pesticides alone achieved 54% control.

Conclusion:
The information collected in this study can be utilized to develop a pest management strategy taking into consideration all the components which may lead to suppress the pest population without relying exclusively on chemical use. This could be achieved through habitat manipulation, which includes maintaining proper sewer system, repairing around the house, fixing water leaks, sealing around electrical plumbing outlets, cleaning, covering garbage cans and tie garbage bags, etc. Pesticides can be used only as a spot treatment in locations where pests were located. Residents education is a major component in the control program because it will improve the awareness about the pest and how to co-operate in the control program.