Qatar Foundation Annual Research Forum Volume 2012 Issue 1

Realization of multilevel inverters for multiphase high power AC drives with open-end windings is presented in this paper, with a specific case of five-phase five-level inverter configurations. The five-level voltage profile is realized by feeding both ends of the stator windings using a three-level five-phase flying capacitor inverter on one side and a five-phase two-level inverter on the other side. The flying capacitors' voltages are effectively balanced by utilizing the switching state redundancies. The capacitor voltages can be balanced at any modulation index, irrespective of the operating power factor. The operation of a drive at a higher voltage is preferred in many applications due to the advantages such as higher efficiency and reduction in size and weight. However, this demands higher DC link voltage in many topologies. The DC voltage magnitude required in the proposed topology is half of that required in the conventional multilevel neutral point clamped (NPC) topology, for a given output voltage. Hence, the scheme proposed in this paper can be advantageous in such applications where there is a limitation in obtaining DC voltage sources of higher magnitudes, such as in electric and hybrid electric vehicles. Another attractive feature of this topology is the enhanced reliability, as it is possible to operate the drive with half power even if any one of the inverters completely fails. The number of active switches used in this topology is lesser than that in equivalent five-level NPC inverters. Unlike the NPC inverter, this topology does not require any clamping diodes and is also free from issues like neutral point fluctuations. A carrier based pulse width modulation (PWM) technique combined with a hysteresis controller for balancing of the capacitors' voltages is used for the control of the inverter. The proposed drive topology can be applied to high power AC drives such as in oil and gas industries, electric/hybrid electric vehicles, ship propulsion, traction etc. The simulation and experimental results support the proposed idea.

The countries of the Gulf Co-operation Council (GCC) have established an interconnected power system network. The primary goal was to share the spinning reserve among the GCC power grids. The project considered the commercial use of the network by aiming to reduce the cost of power generation in the six GCC states while encouraging power trade in order to meet growing needs. The GCC interconnection authority proved its effectiveness and success when, after it was set up, the interconnection contributed in avoiding any partial or total blackout. This was done by passing supported power to any of the first phase connected states. After connecting the first phase of the project, none of the states were compelled to cut loads from their customers. Furthermore, the probability of having a blackout or power shortage has been reduced. The GCC's ambition did not stop at this point. The hope is to connect to neighboring power grids, which could potentially connect to the European Grid. The link, if it took place, would mean great commercial benefits, since peak load seasons in European countries are different from those in GCC countries. In this paper, a study includes an overview of the GCC interconnection, and its benefits are presented. This would emphasize the transfer capability in an interconnection, especially in Qatar, using PSSE program. Moreover, it considers maximizing this capability as a future need to transfer more power through the network. Flexible Alternating Current Transmission System (FACTS) devices are proposed for such purpose. A thyristor controlled series capacitor (TCSC) is selected for enhancing the power capability. This includes an overview, design, and simulation using MATLAB/SIMULINK of TCSC controller.

Cadmium is a naturally occurring metal and is usually present in the environment as a mineral combined with other elements, such as oxygen, chlorine, and sulfur, or as a minor component of most metal ores such as zinc, lead, and copper. Cadmium is also released in the environment from industrial activity; in particular, ore-smelting plants, industrial paints, and agricultural fertilizers. Over the last few decades, considerable attention has been paid to the evaluation and detection of cadmium contamination in the environment, mostly because of the relationship between cadmium exposure and the development of chronic health problems, including renal dysfunction, osteoporosis, and carcinogenesis, as well as developmental and reproductive problems. Water contamination by cadmium is of particular interest because of its high solubility in acidic conditions. Contamination of drinking-water may occur as a result of the presence of cadmium as an impurity in the zinc of galvanized pipes or cadmium-containing solders in fittings, water heaters, water coolers and taps. The aim of this study is to evaluate the availability of cadmium in drinking water in Qatar. Five samples of municipal water were collected from different locations in Doha--Al-Wakra, Dafna, Salwa Road, Al-Kharitiyat and Sailiya--to examine the availability of cadmium in drinking water. Analysis was performed by injecting the samples directly into an ICP-OES machine and obtaining the results. The results showed that the cadmium concentration in all samples was below detection (detection limit for Cd: 0.7 ppb). These low Cd concentrations in drinking water in Doha may be related to the fact that both dissolved and particulate matter are being removed from seawater during the desalination process. In addition, the absence of these toxic elements may be related to the water distribution system being relatively recent and containing cadmium-free pipes.

Qatar established it vision 2030 in October, 2008 (Ibrahim, 2009), adopting the concept of sustainable development. Thus the understanding of the impact of poor wastewater management and degrading sewage systems should be highlighted. Additionally, new technology should be developed to fully decrease the pollution while focusing concern on the economic benefits of the process. We have chosen to evaluate both poultry and slaughterhouse wastewater, since, if discharged into open waterways in an untreated form, it can cause great pollution stress on our environment. To be able to build a proper process for wastewater treatment, we had first to choose the characteristics needed to be identified for better understanding of the local wastewater, to later have informative values at the end. To help us fully understand the chemical and physical characteristics of the wastewater to be treated, we have chosen to measure initial parameters, including chemical oxygen demand (COD), total suspended solids, total dry solids, pH and conductivity. It is well-established that slaughterhouse wastewater is a moderate to low strength complex-type wastewater; thus, the biodegradability of this could be easily achieved if an adapted bacterial population is obtained. Interestingly, we showed that the anaerobic sludge from the Qatari environment is able to treat more than 95% of the wastewater at 38°C, which is favorable and beneficial to develop large-scale anaerobic digestion of the slaughterhouse waste waters given the conditions in Qatar. Consequently, it is possible to conclude that the anaerobic sludge and the temperature applied for the treatment are suitable to overproduce methane from slaughterhouses wastewaters in Qatar's conditions. Our findings showed that almost 1.3 L of methane can be produced by digesting 1 g of COD or dry matter in the slaughterhouse wastewater, which is a very high yield, unprecedented among levels reported for anaerobic digestion.

Companies around the world produce waste as a by-product of their products. The waste products are classified as solid wastes, medical wastes, wastewaters, and different kinds of wastes. Overall, the wastewaters have the highest impacts on the environment, since they are discharged into the seawater, and might also be discharged into the municipal wastewaters. In addition, the composition of the wastewater varies from one company to another, but mainly it contains different kinds of solids either organic or inorganic. The wastewater coming from the slaughterhouses and the poultries is considered one of the most high-impact effluents because of its complex composition. Therefore, the main goal of the project is to use the aerobic reactors in order to treat the wastewater coming from the slaughterhouses and the poultries. The methods used in the project to monitor the efficiency of the treatment, were basically monitoring the changes in the chemical and physical characteristics, like, COD and pH of the effluent during the treatment process, and then to calculate the efficiency of the treatment and the loading rate. The results obtained provided us with the variability of the organic pollutants in the wastewater. For example, the pollution caused by the wastewater coming from both the poultry slaughterhouse and the Mawashi slaughterhouse was low, and the treatment efficiency for the poultry and the slaughterhouse was about 83% and 86%, respectively. In addition, with the loading rates used in the experiment, the efficiency was about 90%, which means that if the residence times increased, the activated sludge reactor would digest the organic pollutants completely.

Nanotechnology is foreseen to change our life by bringing new horizons to current industrial applications. It could be used, for example, to improve the performances of heat exchangers--which are widely used in industrial applications--by augmenting heat transfer characteristics of the working fluids. Nanofluids, which are engineered colloidal suspensions of nano-sized particles (less than 100nm) dispersed in a base fluid, have shown potential as industrial cooling fluids due to their reported enhanced heat transfer characteristics. However, rheological characteristics of nanofluids at extreme working conditions that occur in industrial applications are not well studied. This work for the first time presents the rheological characteristics of cooling oil based nanofluids at high temperatures and pressures. In this work, nanofluids are prepared by dispersing SiO2 nanoparticles (~20nm) in a highly refined paraffinic mineral oil (Therm Z-32, QALCO) that has wide applications in industrial heat exchangers, especially in NGL plants operated by Qatar Petroleum. Three particle concentrations of 1%, 5% and 10% by weight are considered for the investigation. The high pressure and high temperature viscosity values are measured using a HPHT viscometer (METEK CHANDLER ENGG.). In the experimentation, viscosity values of the nanofluids are measured at temperatures ranging from ambient to 160oC, with pressures varying from atmospheric to 100 atmospheres. Initial observations have shown that variation in particle loading and temperature affects the viscosity of nanofluids, whereas increases in pressure had a negligible effect on nanofluids viscosity.

Qatar has experienced an unprecedented development in recent years as a result of its large oil and gas industry. It has the third confirmed reserve of natural gas in the world. With 55.4 tonnes of carbon dioxide per person, Qatar has the highest carbon footprint globally, about 10 times the global average. Against this background, there have been attempts to investigate ways to reduce carbon emissions since CO2 was deemed to be one of the major green house gases. Power generation is by far the biggest contributor to anthropogenic (man-made) carbon emissions. The carbon emission mitigation methods currently considered include both “end of pipe” and “at source” solutions. The techniques currently identified to capture carbon emissions from point sources from industrial activities include post combustion capture, precombustion capture and oxyfuel based capture. These techniques are currently at various stages of development. In this work, an important petrochemical process, namely the Vinyl Chloride Monomer (VCM) process has been selected for carbon footprinting. The primary fossil fuel equivalents, which in turn will be turned into CO2 emissions using combustion processes, were identified. Industrial standard simulation software HYSYS was used to carry out the calculations on the heat duties of the entire plant. Energy intensive sections in the VCM process were identified and their associated CO2 footprint calculated. The total CO2 emissions from VCM plant with a hypothetical capacity of 300,000MT/yr were estimated to be around 96,000 MT/yr, which means that for each 1 ton VCM produced, 0.32 ton of CO2 is emitted. In addition to the process related carbon emissions, non process CO2 emissions were estimated. This emission emanates from energy used to power lighting, electronic equipment, catering, in-house transportation etc. Good practice for energy saving and hence CO2 emission reduction was put forward.

Carbon capture and sequestration (or carbon capture and storage, CCS) is considered to be a critical strategy worldwide--and in Qatar as well--to limit carbon dioxide (CO2) emissions; the main greenhouse gases responsible for global warming. This work focuses on designing a simple device for CO2 capture that can be used in mobile systems like vehicles and ships. The device mainly consists of a compact cylinder filled with an absorbent solution for CO2 emissions. A distributor with a special design is used to increase the area of contact between CO2 gas and the solution in order to increase the absorbent efficiency. Figure 1 shows a schematic diagram of the test rig. Different materials that have high absorption characteristics of CO2, such as NaOH and MgOH, have been used to evaluate the device performance. At the first stage of this work, the CO2 emission has been simulated by injecting a mixture of CO2 and N2 into the device to be used as a proof of concept. A number of parameters, including absorbent material concentration and a mixture (CO2/N2) flow rate, are tested in order to reach the maximum absorption efficiency. CO2 percentage is measured at the entrance and exit of the device to calculate the absorbent ratio with the time. The second stage of this work will include testing the device within an actual internal combustion engine in order to evaluate the device under actual conditions.

Most countries in the world are faced with the dilemma of missing one or more crucial ingredients that prevent them from engaging in environmental research or implementing environmentally friendly policies and practices. Some countries that have the resources to affect change suffer from a lack of political will, whereas others that may have the political will lack the human or technological resources or institutional capacity to affect a change. At present, Qatar is in a unique position for enhancing its environmental performance and sustainability. Endowed by a small population and the world's third largest natural gas reserves, economic resources pose little restraints, and could be converted into building a cleaner future. Education City, Qatar's leading vehicle for building a knowledge economy, incorporates some of the most ambitious environmental sustainability projects and initiatives in Qatar, including sustainable buildings seeking LEED-certification, environmental awareness campaigns, and related practical applications in the areas of solar energy, among others. Apart from this unique concentration of institutions, projects and practices relating to environmental sustainability, the City's cultural diversity makes it a true melting pot of values, perspectives and lifestyles relating to the environment. Education City could provide lessons or even serve as an example of an environmentally sustainable community for the broader society, or will it simply remain a self-proclaimed green community with little impact outside its boundaries? In other words, is Education City a green beacon or is it a green island? This study, funded by the UREP channel of the QNRF, aims to explore environmental sustainability in Education City (EC) and answer the main research question by answering three interlinked, complementary sets of questions, namely: 1) What are the intersections of the vision and EC? 2) How is EC advancing (in) environmental sustainability? 3) Are the university students in EC environmentally sustainable? How about university students in Qatar in general? In addition to providing answers to these questions through qualitative analysis and a survey administered among different universities in the autumn of 2012, this study will seek to identify policy advice and practical applications for environmental sustainability education in Education City and throughout other universities in Qatar.