Qatar Foundation Annual Research Forum Volume 2012 Issue 1

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

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

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

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

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

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

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

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

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

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