Qatar Foundation Annual Research Forum Volume 2013 Issue 1
- تاريخ المؤتمر: 24-25 Nov 2013
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2013
- المنشور: ٢٠ نوفمبر ٢٠١٣
341 - 360 of 541 نتائج
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Bioaugmentation And Biostimulation Studies In The Bioremediation Of Crude Oil Contaminated Gcc Soils
المؤلفون: Farid BenyahiaBioaugmentation and biostimulation studies were carried out on crude oil contaminated GCC soils using a series of engineered biopile systems. The preliminary soil studies clearly showed the poor level of nutrients and low count of indigenous soil bacteria, thus justifying the addition of bacteria and soil nutrients The success towards design of bioremediation systems to treat crude oil contaminated soils crucially depends on the outcome of a series of staged experiments involving soil characterization, oil evaporation and effects of biological and chemical additives to the contaminated soils. The texture, chemical analysis and microbiological character of soils will dictate the level of humidification, biostimulation and bioaugmentation required. Biopile systems have been proved to be effective, controllable and environmentally friendly techniques to treat contaminated soils. Extensive laboratory tests have shown that such systems can be optimized for treatment efficiency and design cost. Ultimately, it is expected that the current landfarming practices would be phased out because of their poor treatment efficiency and displacement of part of the problem from soil to atmosphere. . The performance evaluation of the bioremediation biopile systems which included control systems with no bacteria and indigenous microorganisms, was based on CO2 evolution. The biopile systems bioaugmented and biostimulated showed superior bioremediation activity according to such performance criteria. This investigation has clearly shown the benefits of bioaugmentation and biostimulation in the bioremediation of crude oil contaminated desert soils. The addition of an anionic surfactant enhanced the bioavailability of nutrients and resulted in a faster response to the biological treatment of crude oil contaminated desert soil.
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Autonomous underwater vehicle (AUV) sedimentological study offshore Al-Ruwaiys (North Qatar)
المؤلفون: Christian StrohmengerThe northern limit of Qatar represents a unique depositional environment, reflecting the interplay of coastal processes and sea-level history along the windward margin of the peninsula. The coastline faces directly into prevailing winds, creating distinctive subenvironments. The ecological and geological history of this area is documented for the first time by integrating autonomous underwater vehicle (AUV) surveys and dive-based sampling and documentation of existing maritime data. An AUV collected side-scan sonar imagery, bathymetry, water temperature profiles, sub-bottom profiles and underwater photo mosaics data. Divers followed AUV transects making observations and collecting forty unconsolidated sediment and non-living coral samples. The area of study extends from 500 meters offshore from the island of Jazeerat Reken (Ras Rakan Island), clockwise for 10 kilometers southeast, offshore of the village of Al-Mafyar (Umm Tays Island). North of Jazeerat Reken the seafloor shows a steep margin from shallow subtidal to depths of approximately -7 meters. In contrast the eastern margin of the area, near Al-Mufyar shows a gentle slope, dipping to -6 meters over a 2 kilometer distance. The steep margin along the north coincides with the limits of a fringing reef system that built seaward during the Holocene. Radiocarbon age dates indicate reef growth initiated as early as 5000 years before present, when sea level was 2 to 4 meters higher than today. Two isolated sub-Recent patch reef (reef bommies) trends were discovered offshore of the main fringing reef slope, west of Jazeerat Reken. These offshore isolated patch reefs start at a water depth of about -7 meters and rise up close to present day sea level. The steepest slope of the fringing reef was observed at the northern tip of Qatar, north of Jazeerat Reken Island, where the base of the reef is at about -6 meters. Side-scan sonar imagery and sub-bottom profiling was carried out, revealing a fringing reef slope, the isolated patch reefs and the thickness of the unconsolidated sediment cover of the seabed. Samples from non-living corals were taken for radiocarbon age dating analyses. A sea-level drop approximately 2000 years before present may account for the end of fringing and patch reef growth. Since the sea-level fall, the reef top has been characterized by mobile, coarse coral-algal sands and beach-rock stabilized islands, like Jazeerat Reken. The unique grain size and shape of coral-algal beach sands provide a unique nesting ground for hawksbill turtles (Eretmochelys imbricata). The seabed east of Al-Mufyar (Umm Tays Island) is dominated by carbonate sand bars, separated by brown algae beds attached to the underlying bedrock or hardgrounds. Sediment samples were taken along a 2000 meter long transect perpendicular to the shoreline and side-scan sonar and sub-bottom profiling were carried out in this area. The results of our study provide new insights into changing carbonate platform geometries and related sediment distribution through time; controlled by sea-level fluctuations, as well as wind, tidal, wave, and current conditions. It also provides a template for conducting cost-effective, easily executed ecological and geological studies.
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Quinoa Introduction For Food Security In The Gcc, North Africa And Near East
المؤلفون: Remi PietAnswering the global need to identify crops that have the potential to produce quality food while maintaining sustainable development, quinoa is a cereal that provides significant promises. Thanks to its nutritional characteristics and agronomic versatility, quinoa offers an interesting alternative to traditional crops. Its harvesting contributes to regional and global food security especially in the areas where the population has no access to adequate sources of protein or where food production is limited. Its limited need for water and high protein content make quinoa an ideal candidate for cultivation in food security seeking countries However, the introduction of this cereal holds also its set of challenges including structural changes to the food sector as well as social, economic and environmental factors. This paper analyzes the determinants of production in countries that traditionally produce quinoa (Argentina, Bolivia, Chile, Ecuador and Peru) and underlines the framework of a comprehensive and sustainable production in the Middle East, GCC and North Africa. This research aims at contributing to scientific cooperation, sharing past experiences for the development of this exogenous cereal cultivation at the regional and inter-regional levels, adapting current best practices to local agricultural development. Latin America, North Africa and the Near East share similar challenges as well as geographic, climate and social characteristics, therefore a cross cases analysis is highly relevant. Following a first field study led in collaboration with the United Nations Food and Agricultural Organization (FAO), this paper's objective is to provide a blueprint on how to gather the necessary conditions for a sustainable cultivation of this promising cereal. It also addresses the important capacity building component both at the local and regional level and the inclusion of quinoa within traditional cropping patterns and farming systems as well as national and regional sustainable strategy. More specifically it also focuses on the role the GCC and Qatar could play in fostering cooperation in food security in the Middle East as part of a FAO led scientific cooperation platform in the Greater Middle East. In line with on-going South-South Cooperation efforts, this paper proposes roads to promote not only the exchanges between academic experts from both regions, but also between agricultural cooperatives and traditional food importing countries including innovative financing mechanism.
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Identification Of Gender-Associated Molecular Markers In The Date Palm (Phoenix Dactylifera) Genome
المؤلفون: Maria TorresDate palm (Phoenix dactylifera) is one of the most distributed and well-adapted fruit crops in the Middle East, and plays an important role in the history and diet of the Arab world. Dates constitute the primary exportable agricultural product in Qatar and current efforts are being made to improve its production. Over the years, clonal propagation has been used to maintain selected varieties with desirable morphological traits, leading to the establishment of uniform palm orchards. This, however, significantly reduces genetic diversity among palm plantations, making them potentially more susceptible to pests and diseases. Improvement of date production through date palm breeding is highly challenging due to the long regeneration times and the lack of knowledge about the genetic markers responsible for desirable agricultural traits. In commercial plantations, one hundred fruit bearing female trees can be pollinated with a single non-bearing male tree. Still, half of the date palm offspring planted from seeds are expected to be male individuals. One of the biggest challenges that date production encounters is that female trees can only be distinguished after flowering, which occurs five to eight years after planting. Previous cytological studies have suggested the presence of heteromorphic sex chromosomes in date palm, however enzymatic approaches intended to anticipate gender determination have been unsuccessful. The recent genome sequencing of different individuals from the commercial varieties Khalas, Deglet Noor and Medjool, allowed the identification of a gender-linked genomic region. This single nucleotide polymorphism (SNP)-rich region was shown to segregate with gender, and is predicted to extend to 24 scaffolds. Only a limited amount of information about this region is currently available, and this study proposes the use of a deep-sequencing approach to significantly improve the date palm genome assembly, with an emphasis on the male/female segregating region. A bacterial artificial chromosome (BAC) library, with a 12x genome coverage and an average insert size of 125 Kb was constructed. BAC-end sequencing of at least 96 clones, associated with the polymorphic sex-linked region, will allow the generation a complete physical and sequence map of the sex-determination region. Our main goal is to detect the critical mutation that gave rise to male and female separation. This is the firs time such level of detail in a dioecious plant will be achieved. Furthermore, standardization of this sequencing procedure, will also allow us to characterize other genomic regions associated with desirable commercial properties of these fruits. This in turn, will provide a valuable tool for the development of marker-assisted selection programs, for the improvement of date palm production.
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Effects Of Graphene Materials On The Performance Of Ester Based Drilling Fluid
المؤلفون: Robiah YunusThe idea of pushing the limits of drilling oil and gas wells by improving drilling fluids using conventional macro and micro type fluid additives is very crucial tasks especially to fulfill certain functional tasks. This is due to inadequate information on the physical, chemical, thermal and environmental characteristics of the additives. The industries are currently looking for cost efficient drilling operations, thus many researches are focusing on the wonders of nanotechnology in the drilling fluids which forms the basis of the work presented here. This project will describe the preliminary test results of graphene oxide (GO) and R-graphene oxide (RGO) enhancement as nano additive in drilling fluid formulation. This project is basically to test whether incorporation of graphene materials gives significant improvement to the ester based drilling fluid it terms of its rheological properties. Besides using commercial GO, RGO was synthesized by refluxing the palm oil methyl ester (POME) with graphene oxide for 24 hours. UV-VIS results verified the attachment of R group from POME to the graphene oxide. Both materials then were added to the newly synthesized ester based drilling fluid and then formulations and characterization were performed with different percentages of GO and RGO. The advantages of adding nano-sized molecules of GO and RGO to ester based drilling fluid are evidenced in the improvement in fluid permeability rate into porous formation which contribute to the stability of wellbore.
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Molecular Diversity In Date Palm Using Inter Simple Sequence Repeat (Issr) Markers
المؤلفون: Talaat AhmedTotal of 47 Date palm samples representing 15 cultivars from two germplasm collections (Rodat Alfaras Germplasm field and Germplasm field of Qatar University Experimental farm) were collected to study the genetic diversity among and within date palm cultivars grown in Qatar. 29 samples representing 11 varieties were collected from Rodat Alfaras Farm. Eighteen samples including six varieties were collected from Qatar University Experimental Farm. DNAs were extracted from fresh leaves by using commercial DNeasy Plant System Kit (Qiagen, Inc., Valencia, CA) Total of 18 (Inter Simple Sequence Repeat) ISSR single primers were used to amplify DNA fragments using genomic DNA of the 47 samples. First screening was done to test the ability of these primers to amplify clear bands using Date palm genomic DNA. All 18 ISSR primers successfully produced clear bands in the first screening. Then, each primer was used separately to genotype the whole set of 47 Date palm samples. Total of 4794 bands were generated using 12 ISSR primers for the 47 Date palm samples. On average, each primer generated 400 bands. The Number of amplified bands varied from cultivar to cultivar and differed from area to area for the same cultivar. The highest number of bands was obtained using Primers 2, 5 and 12 for the 17 cultivars over all locations (470 bands), while the lowest number of bands were obtained by Primers 1, 7 and 8 where they produced only 329 bands. However, variation within each individual cultivar as number of polymorphic fragments was considerably smaller than the inter-specific variation among the studied cultivars. Markers were scored for the presence and absence of the corresponding band among the different cultivars grown in different locations. Data were subjected to cluster analysis. A similarity matrix was constructed and the similarity values were used for cluster analysis.
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Ex-Situ Conservation Of Some Plant Genetic Resources From Qatari Protectorates
المؤلفون: Elsayed ElazaziQatar biodiversity is under the pressure by the effects of environmental pollution, overgrazing, desertification as well as the climatic change. In order to rescue wild plant genetic resources of Qatar and in the line of Qatar Strategic action plan of Genetic resources, the present investigation aims at ex-situ conservation of some wild plant genetic resources from Rawdat Umm Al-Kharq. A total number of 17 accessions have collected from Rawdat Umm Al-Kharq, which represent 13 family and 16 Genus,17 Species, during the season of 2013 to target a fully maturated seeds, herbarium specimens and DNA samples. The collection missions follow the principals and guidelines of Plant genetic resources collections set by Biodiversity International and international gene banks. The collected materials are subjected to characterization, documentation and preservation process. According the international conservation rules, cleaning, drying, viability test, packaging and storing were applied for seeds. Highly seeds viability recorded with Cucumis prophetarum, Malva parviflora, and Salvia aegyptica. All information derived from conservation process was documented in the Biotechnology Center. Key words: Biodiversity,Plant Genetic Resources, gene bank, Conservation, Qatar.
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A green solution: Molecular dynamic simulation study of wax inhibition through pour point depressant type inhibitor
المؤلفون: Fatmawati AdamParaffin wax deposition from crude oils at low temperature is one of the critical and long standing problems in petroleum industry. An addition of pour point depressants (PPDs) has been proved to be an efficient way to inhibit the wax deposition. The chosen group of PPDs in this study are poly(ethylene-co-vinyl acetate(EVA)) and (Meth)acrylate Ester (MAE) polymers. The molecule geometry structures were labelled as illustrated in Figure 1. This research focuses on the investigation of van der Waals intermolecular interaction between the major wax component molecule C28H58, with the inhibitor molecules via molecular dynamics simulation (MD) technique in Material Studio 5.5 software Package. The simulation system has been equilibrated under NVE essemble at 200ps followed by NVT assemble. COMPASS force field is applied to analyse the desired structural property Radial Distribution Function (RDF). The results show that the functional groups introduced by EVA were benefit to inhibit the self-agglomerate of the wax crystal compared to MAE as reported in a published literature. Simulation output also provides a better understanding on the interaction between wax crystal and inhibitors. The oxygen atoms in EVA play a significant role to inhibit the wax formation through the van der Waals interaction between hydrogen atoms in n-Octacosane molecule. As a conclusion, MD is a promising tool method to recognise the wax-inhibitor intermolecular interaction which is much fast, environmental friendly and economic for further inhibitor screening work. Keywords: poly(ethylene-co-vinyl acetate(EVA)),(Meth)acrylate Ester (MAE) Polymers, COMPASS, van der Waals
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The control of Gas Hydrate formation using ionic liquids
المؤلفون: Majeda KhraishehGas hydrates are crystalline solids consisting of three dimensional, hydrogen bonded water molecules (host), encapsulated with a guest molecule. [1] There are numerous possibilities for the molecules acting as the guests. The most common guests include methane, ethane, propane and carbon dioxide. They can be significantly problematic in the production of oil and gas. The 1930's marked the discovery, by Hammerschmidt, of the formation of hydrates in pipes. This formation can eventually cause a blockage in the pipeline, creating the risk of explosion, as the blockage may cause a high pressure and low pressure section of the pipe. This causes the hydrate to act as a high velocity solid which not only results in destruction to equipment but can also lead to loss of lives. [2] As the production of oil and gas moves to more extreme, hydrate favouring conditions, predominantly inhibition is the only viable option. Clathrate hydrate inhibitors are divided into three groups, thermodynamic inhibitors (THI), low dosage hydrate inhibitors (LDHI) and ionic liquids (IL). Ionic liquids have the potential to act as inhibitors but previous research has been restricted by the lack of design on the ionic liquids being experimented e.g ionic liquids chosen due to their commercial availability. There are many advantages to using ionic liquids, but in increasing their field application certain design criteria should be followed. The Ionic liquids used should be water soluble, form hydrogen bonds with water, relatively non-viscous, low toxicity, biodegradable and have minimal halogen content. The main aim of this work is to Design, Synthesise and Characterise ionic liquids within the criteria that will perform as hydrate inhibitors and to test the ionic liquids as both thermodynamic and kinetic inhibitors in the high pressure view cell and compare the performance with current commercial inhibitors.The initials experiments were performed to ensure the equipment was fully working and so the literature data for the blank test with no inhibitor and methanol 5 and 10 wt% were reproduced to verify thisAs can be observed from the graph, the literature data has successfully been repeated. This is also shows that the equipment is working and is operating to the desired needs of the project. Frequently imidazolium cations, particularly EMIM, are observed in the literature featuring ionic liquids as inhibitors. The next stage was to look at how effective these ionic liquids are, however, exchanging the halogen anion. The properties mentioned before suggest alcohol or ketone groups on the anion in order to maximise hydrogen bonding effectively increasing inhibition ability. This change would also help in making the ILs more environmentally friendly and lower the toxicity of them.
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An Experimental and Computational Approach On Avoiding Gas Hydrate Problems in Qatar's Oil and Gas Industry
المؤلفون: Mert AtilhanQatar's one of the biggest problem in processing its natural resource, which is natural gas, is the often occurring blockage in the pipelines caused due to uncontrolled gas hydrate formation in the pipelines. Several millions of dollars are being spent at the process site to dehydrate the blockage safely by using chemical inhibitors. We aim to establish national database, which addresses the physical conditions that promotes Qatari natural gas to form gas hydrates in the pipelines. Moreover, we aim to design and test novel hydrate inhibitors that are suitable for Qatari natural gas and its processing facilities. From these perspectives we are aiming to provide more effective and sustainable reservoir utilization and processing of Qatari natural gas. In this work, we present the initial finding of a big project, which deals with the natural gas hydrate formation characteristics of Qatari type gas in both experimental (PVTx) and computational (molecular simulations) methods. We present the commissioning of the new fully automated gas hydrate autoclave and measurements of hydrate equilibrium curves including growth/dissociation conditions for multi-component systems for several gas mixtures with and without the presence of well known kinetic and thermodynamic hydrate inhibitors.
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Natural Gas Hydrate Equilibrium Experiments for Qatar Natural Gas Samples
المؤلفون: Mert AtilhanQatar holds the world's third-largest reserves of natural gas at 890 trillion cubic feet according to proven reserves according the latest report in 2013. This plentiful natural resource makes Qatar being one of the most important key players in LNG business around the globe. Qatar's natural gas reservoirs are located 80 km off the shore in North Field. Qatar's LNG production is highly dependent on the reliable natural gas feed from the offshore wellheads to on shore processing facilities. Typical gas composition and pipeline operating conditions makes the flow assurance quite challenging in the North Field which causes unplanned shutdowns and jeopardizes the reliable LNG export to end users. Classical hydrate formation inhibition methods are used in order to prevent plugging of the pipelines however gas industry still suffers from hydrate formation conditions for changing gas concentration, determination of the total amount of inhibitors to be injected and the recovery of the injected inhibitors from the pipeline. These challenges make gas industry in Qatar dependent on the external resources in finding temporary solutions, which currently is not available locally in Qatar. This work presents recent investigation on natural gas hydrates for Qatari type natural gas mixtures with initiatives aimed at helping producers minimize costs, optimize operations, and prevent interruption of gas flow in offshore drilling and production. We present preliminary results and data from a newly commissioned high pressure hydrate autoclave. Calibrations of the autoclave with pure methane and carbon dioxide were compared with literature and Hydraflash software. Upon validation of the calibration data and determination of the apparatus uncertainty, results for hydrate formation equilibrium points for Qatar natural gas sample were collected and were compared with a theoretical data obtained from Hydraflash software.
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Application a statistical method for simulating PM10 concentrations distribution in urban receptors: Case study of Tehran
المؤلفون: Mohammad RahimiThe achievement of air quality standards (AQS) is the main concern of air quality managers. In the semi arid and arid areas such as Qatar, dust storms release large amounts of particulate into the atmosphere every year, which can cause serious health problems such as lung irritation, allergic reactions, eye infections, meningitis. The present research aims at simulating PM10 concentrations distribution in Tehran by lognormal statistical distribution method during a bit more than 2-year period (2011-19 January 2013). With respect to statistical properties of air pollutants, the number of exceeding daily average concentrations from assigned air quality standards (AQS) can be estimated, as well as the level of reduction in current emission sources of PM10 required in order to meet the AQS. The results show that the distribution of PM10 concentration could be in?uenced by local meteorological conditions in di?erent seasons .In addition, the emission sources reduction of PM10 concentration to meet the air quality standard (PM10> 50µg/m3) for Fath's station is successfully predicted.
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Wide-bandwidth Solar energy harvest by using non-linear optics and fluid dynamic
المؤلفون: abul hasanat jahanur rahmanExisting solar technology can convert only limited bandwidth of solar rays into electricity due to the Shockley-Queisser limit of the solar diodes. Rest get wasted by heating up the solar array or reflected back. This proposed method increases this bandwidth range significantly. Thus produces high yield of electricity. Thin organic solar panel sheet is coated for reflecting non-absorbed bandwidth of sun rays. This sheet can be bend into concave shape with different focal radius. By using solar cell mirror made of this panel with MPPT, a solar farm can be made that converts some of the solar energy into electricity and reflects rest of the solar bandwidth into one single focus location where a series of lenses and prisms are located. These series of lenses converts the incoming bandwidth of rays into tightly focus collimated Gaussian beam which goes through two heterogeneous or multimode circular prisms in a close loop waveguide for ring lasing pulse generation. These prisms have layers of different refractive indexes. So, higher frequencies come out near the circumference of one of the prism and lower frequencies come out from its center. And the other one has opposite effect. First beam goes through a pipe in which fluid is flowing in opposite direction and the other beams at the opposite side enter through the same direction of the fluid flow. Two beams are tuned to be out of phase. This increases absorption by fluid due to destructive effect of the beams. The viscosity of the fluid is controlled through varying temperature and pressure. It is mostly kept in a controlled laminar flow, where center fluid layer has higher velocity than the boundary layer. This superfluid needs to be both electrical and thermal conductive. The spectrum in which beam is divided, the higher frequency rays (UV, X- rays) hit the lower velocity fluid layer (near boundary) and lower frequencies (infrared) for higher velocity fluid layers (near center). Similar to laser cooling technique, all fluid atoms are excited to same virtual energy state depending on thermal stability. Depending on the intensity of this two photon absorption and above threshold energy level in the continuum, either free electron or higher harmonics (HHG) can be generated by four wave-mixing, self-phase modulation and Raman scattering process within this non-linear superfluid. This superfluid II supports magnetic vortices that confined the free electron or induced hyperpolarized fluid atoms. Through mode locking technique these higher harmonics can form high intensity femtosecond pulse that can be used to produce electricity in a plasma cavity and multi-channel plates (MCP). Since all fluid atoms are excited at same population average energy, the emitted side-bandwidth beside the pulse is very narrow, which can be converted into electricity by using conventional solar tiles. The other outcome is cooling effect because fluid gets cool down due to losing kinetic energy. This new method can not only produce high volume power generation but also provide temperature controlling system for a city that is especially located in desert.
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Simulation Of The Fischer-Tropsch Fixed Bed Reactor For The Design Of Novel Gtl Process In Non-Conventional Reaction Media
المؤلفون: Nimir ElbashirFischer-Tropsch synthesis (FTS) is a key technology for converting syngas (H2/CO mixture) into a variety of hydrocarbon products via the gas-to-liquid technology (GTL) process. Although this technology has existed for decades, commercial development remains limited to a few reactor configurations (e.g. fixed bed reactor, fluidized bed and slurry reactor). On the lab-scale, the utilization of supercritical fluids as reaction media in FTS was shown to combine the advantages of both the gas-phase (fixed bed) and the liquid-phase (slurry) reactors, while simultaneously overcoming their limitations [1]. Our previous studies in this field reported the challenges facing the design of a novel supercritical fluids FTS reactor technology [2,4]. The current study focuses on modeling the in situ behavior of typical SCF-FTS reactor bed ('macro-scale' assessment) as well as catalyst pellet ('micro-scale' assessment). This research has several objectives; however its main scope is to provide both qualitative and quantitative assessment of the in situ behavior of the non-ideal reactor bed relative to the conventional gas-phase fixed bed reactor technology, as a first step towards industrial scale-up. The specific aims of our paper are as follows: to simulate the heat and mass transfer behavior inside the reactor bed; to identify operating conditions using near- or supercritical fluids capable of overcoming mass and heat transfer limitations inside the reactor bed; and to quantify the role of the main controlling parameters on the reactor bed behavior as measured by the catalyst effectiveness factor. A typical mathematical modeling technique for the fixed bed reactor was applied to simultaneously simulate the concentration and temperature profiles inside the catalyst pores (micro-scale modeling) and inside the reactor bed (macroscale modeling) [5-7]. For the micro scale simulation of the in situ behavior inside a spherical catalyst pellet a second order ordinary differential equation was used to describe both the mass and heat balances. For the macro scale modeling a 1D steady state pseudo homogeneous plug-flow model was used. In addition, in both models the mass balance equation was expressed in terms of fugacity to account for the non-ideal behavior of the reaction mixture in the SCF reaction. The thermodynamic properties of the mixture were calculated using the Soave-Redlich-Kwong equation of state (SRK-EOS). Using this methodology, the effect of pressure in the (near)-critical fluid (SCF) assisted reaction, and the effect of the (near)-critical fluid on heat transfer and temperature distribution within the reactor was investigated. We also investigated the effect of the particle size on the overall catalyst effectiveness factor for both the SCF and gas phase FTS. Figure1 and Figure2 show the temperature and conversion profiles under comparable conventional gas phase reaction and SCF reaction conditions. The most dramatic effect can be found in the temperature distribution profile. Due to the presence of the solvent the generated heat is absorbed, leading to a much smoother temperature profile. In general, this study will provide a comparison between the in situ behavior and the catalyst effectiveness factor for the proposed novel process versus the conventional gas-phase FTS reactor bed under equivalent operating conditions.
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Boiling Of Binary Hydrocarbon Mixtures On Water
المؤلفون: Tomasz OlewskiThe boiling of binary hydrocarbon mixture on water exhibits a special immiscible liquid-liquid heat transfer phenomenon where the heat transfer parameters change rapidly in a short duration of time. The boiling of hydrocarbon mixtures involves a process called ageing where the vaporization of most volatile component takes place faster leaving behind the less volatile component. This process establishes a concentration gradient which changes with time. The boiling heat flux thus produced for mixtures is quite different from this of the pure component. In the boiling of a pure liquid the entire boiling process is heat transfer controlled. In contrast, when a multicomponent mixture boils, the vapor and liquid phases are present in different composition and boiling process is controlled by both temperature and concentration gradients. The boiling of two different binary mixtures of hydrocarbons comprising of methane-ethane and methane-propane was studied. Theoretical correlations for nucleate and film boiling, which takes into account the modified heat transfer coefficient and wall superheat heat, were used to determine the heat flux. The modified heat transfer coefficient called ideal heat transfer coefficient was found to be a function of the concentration of the light components. The ageing of the mixture was expressed as a ratio of heavier to the lighter hydrocarbons. Predicted heat flux values were compared against experimental data and showed moderate-good fitting with the model with some identified trends.
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Optimal Policies For The Diffusion Of Renewable Energy Systems
المؤلفون: Shadi GoodarziClimate change, caused by excess green house gas (GHG) emissions from human activities is becoming a pressing problem as the Earth's mean surface temperature has increased by about 0.8 °C since the early 20th century (America's Climate Choices, 2011). It is now widely accepted that investment in renewable energy sources is one of the most effective solutions to amend the emission of GHGs. Yet renewable energy technologies only account for a small fraction of the world's primary energy supply. Several technical, economical and behavioral reasons hinder market diffusion of these technologies; among these we note the lack, inadequacy or instability of the governmental policies to promote sustainable energy solutions. Various policies such as subsidies and tax reductions have been implemented to facilitate the diffusion of renewable energy systems. Yet, there is limited research on which policy is optimal, taking into account the complexities and externalities in the supply chain of such renewables as Photovoltaic (PV) systems. Using a stylized economical model, this research aims at identifying optimal policies for adoption of PV systems. We develop a model with a 3-player environment, which includes a grid operator responsible for meeting electricity demands, a PV manufacturer, and customers who are sensitive about their investment payback time with heterogeneous 'discount rate', reflecting their attitude toward the time value of money. The grid operator is responsible to meet all electricity demand, while aiming at increasing PV penetration. The PV manufacturer as well as the customers seeks to maximize their own profit/utility. The decision variable for the customers is whether or not to adopt the system, affecting profit of the two other parties by determining the demand as well as the amount and variation of the electricity fed into the grid using the PV systems. The decision variable for the PV manufacturer is the price to charge for each PV unit, while the grid operator decides on the incentive schemes for adoption including feed-in tariffs and subsides. We investigate the equilibrium outcome in this intertwined decision environment as a sequential game, where the manufacturer determines the price of PV units given the governmental incentive systems, and the customers determine demand. Using this equilibrium outcome, we then investigate the effectiveness of various incentive policies to maximize supply chain profit as well as PV penetration.
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First Record Of Pseudoceramodactylus Khobarensis Haas, 1957 (Reptilia: Squamata: Gekkonidae) In Qatar
المؤلفون: Aitor ValdeónThe Gulf sand gecko (Pseudoceramodactylus khobarensis Haas, 1957) is a nocturnal gecko endemic to the Arabian Gulf countries (Saudi Arabia, Kuwait, Bahrain, United Arab Emirates, Oman and Iran). The species is easily recognizable, being a medium sized ground dwelling gecko with no enlarged tubercles on the dorsum nor lamellae beneath toes, like Stenodactylus species, but Pseudoceramodactylus khobarensis has at least one pair of enlarged postmental scales, absent in Stenodactylus species. In this study we report the presence Pseudoceramodactylus khobarensis in Qatar for the first time. We found the species on two islands (Al Aaliya and Al Saflia) and in the mainland (Abu Samra and two areas in Ras Laffan). The islands are the smallest where this species is known to occur. The habitat occupied by the geckos consists of salty coastal areas with shrubs. Our findings in this study bridge one of the current geographic gaps in the known distribution range of this species. We believe that this gecko species is more widely distributed in Qatar than we report here and an extensive inventory is required to map the full range of the species in Qatar and also in other countries of the Arabian Gulf. This abstract is a contribution for the Qatar Foundation Annual Research Conference (QF-ARC-2013).
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Characterization And Application For Qatalum'S First Cut Spent Spot Lining
المؤلفون: Aboubakr AbdullahSpent spot lining (SPL) is a graphite/ceramic waste that is produced from the aluminum industry. The rate of SPL production is expected to increase worldwide by 500,000 tons per year. SPL is considered as a hazardous material since it contains many contaminants e.g. fluorides, cyanides, lead and chromium in addition to flammable gases when it comes in contact with water e.g. ammonia, phosphine, hydrogen and methane. Hydrogen and methane accounts for approximately 99 percent of gases generated. These gases are released slowly for significant lengths of time which could present an explosion hazard in confined or poorly ventilated spaces. Furthermore, the SPL contaminants can diffuse to the water ground during storage. The aims of this work are to (i) design and verify a full analysis protocol for the SPL and (ii) find a suitable application for consuming the SPL waste. SPL was collected from Qatalum, grinded using a ball miller and then washed with water, conc. HNO3 and finally with conc. NaOH. The evolved gases in each stage were collected in gas collection bags and analyzed using gas chromatography. Also, the eluents from the different washing steps were collected for the induced coupled plasma (ICP) analysis to determine the concentration of the different trace metals. Furthermore, a qualitative analysis for the anions was done. Part of the graphite was transformed into graphene which later was was functionalized in two different ways to add acidic and basic moieties on its surface to trap basic and acidic gases, respectively which are evolved during the washing and chemical treatment of the SPL.
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Principles For Sustainable And Efficient Settlements, Based On A Multi-Agent Interface Between The Physical Spaces Structure And The Energy Grid
المؤلفون: Giovanni Luigi La RoccaThe “multi-agent systems” approach allows to model the interaction between various entities (agents), through an organization that helps to simplify problems with a high number of freedom degrees. An agent is a semi-autonomous entity that interacts with the surrounding reality through its own system of decision, cognition, communication and organization. The research project aims to define a relationship between the design of the energy system and the suitable organization of the physical spaces. The livable conditions for the physical spaces need a strong relationship between the natural resources and the environment artificial transformations. These ones include architectural and engineering approaches in order to generate an integrated design where active and passive solutions produce advantageous gains also in terms of duration and quantity. A specific goal of the research consists in exploring the agent approach in order to integrate, in a compensatory way, the energy system and the physical space structure, defining the agent itself as their interface. At the change of the environmental conditions, the agent minds to preserve efficiently the optimal habitability conditions of the urban and architectural spaces. To reach this result, it will be used its feature to interact with the space in which it is immersed. In this case, the interaction is established with the control system of the comfort standards, defining: * Firstly, the use of active and passive devices of exploitation of the direct gains (i.e. solar, wind, etc…); * Secondly, the use of the energy network, to compensate the passive gains and the energy exchanges with the other elements of the network. The control framework of the agent will be determined through a mathematical model whose variables derive from the physical space and the energy system. Through this system, the research project will deal with a series of issues that contribute to define a sustainable and efficient settlement: * A coherent management of different environmental resources oriented towards new livable and meaningful public and private spaces conception; * The mobility network system improving the settlement structure and its functionality, through the target of car-free living and car-sharing; * The problem of synchronization of distributed energy generation and the quality of the electric power fed into the urban micro-grid. The research will be structured through the following phases: 1) Definition of the invariants on which to work: - Climate; - Geomorphology; - Urban morphology; - Building morphology; - Energy production and consumption; - Usable renewable energy sources. 2) Definition of the "agent interface": role, control features and mathematical law; 3) Modelling different urban structures; 4) Experimentation of the model, through: * Software simulations; * Realization of the model prototype, defined on the base of the simulations. The agent architecture contributes to the energy efficiency (at both the urban and building scales) implying an energy management based on: * The analysis of the effective needs; * The use of sharing and self-sufficient strategies. The expected results consist in defining possible guidelines suitable in designing new space organization as well in restructuring the existing structures.
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The Impact Of Information Sources And Perceived Technological Uncertainty On The Adoption Of Photovoltaic Systems
المؤلفون: Shadi Goodarzi*The increasing attention received by environmental problems in general and by global warming in particular reignites the debate around the sustainability of energy sources and renewable energy technologies. Renewable energies (RE) are considered one of the most effective and least risky solutions to curb greenhouse gas emissions. By providing emission-free and sustainable energy, these energies are main alternatives to fossil fuels. Yet, notwithstanding the advantages and the fact that they have experienced a substantial growth over the last decade, RE market penetration still remains below the levels judged necessary to effectively curb C02 emissions. Increasing RE penetration requires therefore that concerned actors such as RE companies and policy makers develop a more thorough understanding of the factors that affect the RE diffusion process. To that end, in this study we adopt a new technology diffusion perspective to shed further light on the factors that may hamper or accelerate the diffusion of a specific type of RE: photovoltaic systems (PV). We especially discuss and examine the impact of the following factors: i) the type and amount of PV-related information acquired by potential adopters; ii) the perceived economic value of PV; iii) the role of technological uncertainty and iv) the degree of competition in the PV market. We put forth a conceptual model of PV diffusion and we test it using primary data obtained through a survey of the actual and the potential clients of a large European utility that also sells PV systems. We used a set of logit models to estimate the impact of the above factors on the probability of adopting a PV system and we examined possible second order and interaction effects between these factors. The analysis provides interesting insights, particularly with respect to the role of information and the process through which it is acquired by potential adopters. Most importantly, the results indicate that information acquired through personal contacts (e.g. by visiting stores or talking to friends and colleagues) has a much greater impact on the probability of adoption than information filtered by other types of media (e.g. obtained from the web). This indirectly stresses the key role played by retailers, who guarantee a face-to-face contact with potential customers. Second, our results show that, contrary to expectations, increasing the number of market competitors decreases the probability of adoption, possibly because potential adopters defer their adoption decision when the number of available alternatives increases beyond a certain limit. Interestingly, we also note that the impact of perceived economic value and technological uncertainty is not significant, as if PV systems had already reached a minimum level of cost competitiveness and technological maturity. Altogether, our results indicate that - in addition to focusing on improving technological effectiveness and reducing system cost, RE providers should pay a lot of attention to the way they organize their distribution channels and to how they design their marketing campaigns. *The authors gratefully acknowledge the support of the Qatar National Research Fund (project n. NPRP 5 - 873 - 5 - 133
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