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Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1

  • Conference date: 22-23 Mar 2016
  • Location: Qatar National Convention Center (QNCC), Doha, Qatar
  • Volume number: 2016
  • Published: 21 March 2016

101 - 120 of 656 results

    • Machine Learning-Based Building Energy Consumption Prediction

      https://doi.org/10.5339/qfarc.2016.EEPP2582

      Energy is the lifeblood of modern societies. In the past decades, the world's energy consumption and associated CO emissions have increased rapidly due to the increases in population and comfort demand of people. In this decade, the increase in energy consumption and associated CO emissions are expected to continue due to the demand coming from developing countries such as China, India, and some Middle East countries. Negative environmental impacts, such as air pollution and global warming, are being triggered by the generation and use of non-renewable energy, including oil and natural gas. Buildings are a significant source of the world's energy consumption. The building sector is responsible for 39% and 40% of the energy consumption and 38% and 36% of the CO emissions in the U.S. (Becerik-Gerber et al. 2014) and Europe (Ahmad et al. 2014), respectively. Buildings, therefore, offer a great potential for reducing the world's energy consumption and limiting the negative impacts caused by the use of non-renewable sources. Improving building energy efficiency is one of the best strategies for reducing the energy consumption of buildings, while maintaining the comfort and well-being of the building occupants. Building occupants care about their comfort and well-being, as well as about the energy cost and the environment. A recent study showed that thermal comfort, visual comfort, indoor air quality, health, personal productivity, energy cost saving, and environmental protection are moderately important or higher to residential and office building occupants (Amasyali and El-Gohary 2016).

      In this regard, building energy efficiency drew a lot of research attention; a relatively large number of research studies have been undertaken in the field of building energy efficiency. These efforts can be classified into five categories: (1) efforts to improve the efficiency of building appliances and materials; (2) efforts toward increasing the use of renewable energy sources; (3) new policies, incentives, and regulations to reduce energy consumption; (4) efforts toward improving occupant behavior, and (5) efforts to automate building control. Studies in all these categories require accurate building energy consumption prediction for improved energy decision making. Building energy software tools (physical models), such as EnergyPlus and eQuest, are being widely used for energy consumption prediction. These tools are, however, very elaborate and therefore requires a significant number of input parameters that are not always available to users. In order to predict energy consumption of buildings without many input parameters, data-driven models were developed. Data-driven approaches utilize historical input data (e.g., outdoor weather conditions, electricity consumption) for developing a prediction model. In any data-driven approach, developing a model consists of four steps: data collection, data preprocessing, model training, and model testing. In the area of building energy consumption prediction, the types of data collected could be data from sensors that are utilized in empirical building energy studies, data generated by a building energy simulation software, or data from publicly available generic datasets (e.g., datasets provided for energy consumption prediction competitions). Data preprocessing includes data cleaning, data transformation, data normalization, and data interpolation. Model training is the training of the prediction model using the historical data. Support Vector Machine (SVM), Artificial Neural Networks (ANN), decision tree, and statistical techniques are the most commonly used training algorithms and techniques. Model testing is the evaluation of the prediction model using some standard evaluation measures.

      This paper presents a data-driven building energy consumption model. The authors used publicly available generic data and sensor data: the ASHRAE's Great Building Energy Predictor Shootout dataset (ASHRAE dataset) and a dataset gathered from an office building in Philadelphia, PA which was instrumented and monitored for this study (PA dataset). The lengths of the ASHRAE and PA datasets are six and two months, respectively. These datasets were cleaned, transformed to the format required by the learning algorithm, and normalized. SVM was used as the training algorithm. SVM is a kernel-based machine learning (ML) algorithm that can be used for both regression and classification (Wu et al. 2008). The goal of this algorithm is to find a function f(x) that has at most epsilon (ε) deviation from the actually obtained target yi for all the training data and at the same time is as flat as possible (Vapnik, 1995). The algorithm can solve non-linear problems even with a small amount of training data (Zhao and Magoules 2012). SVM is one of the most robust and accurate algorithms and has been listed in the top ten most influential data mining algorithms in the research community by the IEEE International Conference on Data Mining (Wu et al. 2008). It was found to outperform other ML algorithms in numerous applications. For model testing, the coefficient of variation (CV) and the mean bias error (MBE) were used to evaluate the performance of the models in predicting energy consumption. CV and MBE are performance criteria, provided by ASHRAE, for evaluating energy consumption level prediction algorithms. CV determines how much the overall prediction error varies with respect to the target's mean and MBE determines how likely a particular model is to over-estimate or under-estimate the actual data (Edwards et al. 2012).

      The LIBSVM software package was used to implement the SVM algorithm. Eight input parameters were used for the prediction model: outdoor dry-bulb temperature of the current hour, outdoor dry bulb temperature of the previous hour, solar radiation intensity of the current hour, solar radiation intensity of the previous hour, wind speed of the current hour, relative humidity of current hour, energy consumption of the previous hour, and energy consumption of the two hours ago. The following model parameters were used: nu-SVR (type of SVM), radial basis function (kernel type), and 1500000 (cost). As shown in Fig. 1, the predicted results of the model on the ASHRAE dataset, showed a good fitness with the actual energy consumption. In the end, the models showed that it has many promising features that could make it more reliable for effective energy decision making. The model achieved 3.71% CV and 0.30% MBE.

      The authors are currently working on improving the accuracy of the model based on the ASHRAE dataset, as well as extending the model to an occupant-behavior-sensitive energy consumption prediction model based on the PA dataset. The model will be able to predict overall building energy consumption on a daily, hourly, and sub-hourly basis. It will predict energy consumption based on (1) indoor environmental condition data (e.g., indoor temperature and relative humidity), (2) occupant energy use behavior data (e.g., thermostat setpoints), and (3) outdoor weather condition data (e.g., ambient temperature and ambient relative humidity). The authors will also focus on: (1) assessing the effectiveness of utilizing indoor environmental condition data and occupant energy use behavior data for energy consumption prediction, using sensitivity analysis that are going to be conducted individually for the daily, hourly, and sub-hourly prediction models, and

      (2) comparing the performances of the daily, hourly and sub-hourly prediction models. Ahmad, A. S., Hassan, M. Y., Abdullah, M. P., Rahman, H. A., Hussin, F., Abdullah, H., & Saidur, R. (2014). A review on applications of ANN and SVM for building electrical energy consumption forecasting. Renewable and Sustainable Energy Reviews, 33, 102–109.

      Amasyali, K., & El-Gohary, N. M. (2016). Energy-related values and satisfaction levels of residential and office building occupants. Building and Environment, 95, 251–263.

      Becerik-Gerber, B., Siddiqui, M. K., Brilakis, I., El-Anwar, O., El-Gohary, N., Mahfouz, T., … & Kandil, A. A. (2013). Civil engineering grand challenges: Opportunities for data sensing, information analysis, and knowledge discovery. Journal of Computing in Civil Engineering, 28(4), 04014013.

      Edwards, R. E., New, J., & Parker, L. E. (2012). Predicting future hourly residential electrical consumption: A machine learning case study. Energy and Buildings, 49, 591–603.

      Vapnik, V (1995). The Nature of Statistical Learning Theory. Springer-Verlag New York, Inc., New York, NY, USA.

      Wu, X., Kumar, V., Quinlan, J. R., Ghosh, J., Yang, Q., Motoda, H., … & Steinberg, D. (2008). Top 10 algorithms in data mining. Knowledge and Information Systems, 14(1), 1–37.

      Zhao, H. X., & Magoulès, F. (2012). A review on the prediction of building energy consumption. Renewable and Sustainable Energy Reviews, 16(6), 3586–3592.

    • Effect of Surface Oxidation on Performance of TiCTx/MO Composite as Anode Materials for Lithium Ion Batteries

      https://doi.org/10.5339/qfarc.2016.EEPP2596

      Recently, a new group of 2D material showed a great promise in supercapacitors and batteries application due to their good conductivity as well as hydrophilic nature [1]. It has general formula Mn+1Xn, where n = 1, 2 or 3, M is an early transitional metal and X is C and/or N [2]. According to X-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectrometry (EDS) studies, MXenes can be terminated with a mixture of O, OH, and/or F groups depending on the chemical etching method and post-treatment. The as-synthesized MXenes are electronically conducting and hydrophilic, which is a unique combination. Ultrasonication can be used to delaminate the 2D layers and produce single-layer and few-layered flake [3].

      As MXenes are hydrophilic, once delaminated, they form stable, surfactant-free colloidal solutions in water. The possibility of intercalating MXenes with various organic molecules plays a critical role for utilizing MXene in a range of applications, from polymer reinforcements to energy storage systems. The MXenes’ 2D morphology, together with to their good electronic conductivities, render them strong candidates for many applications that range from sensors and electronic device materials to catalysts in the chemical industry, conductive reinforcement additives to polymers, and electrochemical energy storage materials, among many others [4].

      We have used hydrothermal route to synthesize nanocomposite material i.e. TiCTx/MO (MO = FeO, CoO). After hydrothermal treatment, nanocomposite was calcinated at 400°C for 4 hours to get rid of entrapped moisture. Nano-composite was characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. After synthesis, nanocomposite was applied as anode in lithium ion battery. Anode was fabricated as thin film using doctor blade on copper foil.

      TiCTx/FeO composite as anode material exhibited discharge and charge capacities of 190 and 120 mAh/g, respectively. Characterization shows that the MO nanoparticles are not uniformly distributed and also X-ray diffraction analysis has confirmed that TiCTx has oxidized during hydrothermal treatment. Due to oxidation, the surface of TiCTx was decomposed to TiO and leaving carbon sheets behind which played a big role in decreasing conductivity of the anode. In turn, it has greatly affected its performance as anode material in the lithium ion batteries. To enhance its performance as anode material in Lithium ion batteries, it is extremely important to protect it from oxidizing. For this purpose, it should be exfoliated in a medium other than water. Besides this, metal oxide should be uniformly distributed.

    • Qatar: A Valuable Resource for Autochthonous Microalgae with High Potential for Biofuel Production and Food Security

      https://doi.org/10.5339/qfarc.2016.EEPP2599

      Algae-derived products, in particular biodiesel, have received increased interest over recent years due to their advantages over fossil fuel derived products. The ability of algae to grow in different qualities of water, with high areal biomass productivities, and photoautotrophic capacity using sunlight and CO as a source of energy, are just of few of their advantages. Due to the high biodiversity of microalgae and cyanobacteria, the selection of a suitable strain is paramount for successful development and commercial application of microalgae, be it for biodiesel production or, other applications such as products for the nutritional, pharmaceutical and chemical industries. This encouraged the scientific community to establish supporting culture collections of marine and fresh water microalgae and cyanobacteria from a range of diverse environments.

      The isolation of autochthonous microalgae, with high lipid-contents and biomass productivities is a crucial aspect of the development of commercial production of microalgae-based biodiesel as well as food security in land-locked locales. This is especially important for deployments in climates such as are found in Qatar, a peninsula in the west Arabian Gulf, which is characterized by an extreme desert climate.

      The present research work describes the establishment of the Qatar University Culture Collection of Cyanobacteria and Microalgae (QUCCCM). Indeed, different strains of cyanobacteria and microalgae were isolated from various local environments, ranging from freshwater bodies to marine environments, as well as from soil, sabkha and rocks. Strains were subjected to intensive purification and subculturing, and characterized at the morphological and molecular levels. Selected strains were characterized for growth rate, and secondary metabolite production in order to identify important strains with high potential for large-scale outdoor culture, specifically for biofuel production.

      53 autochthonous strains of microalgae were isolated from various freshwater, marine and terrestrial environments in Qatar that led to the establishment of the Qatar University Culture Collection of Cyanobacteria and Microalgae (QUCCCM). Strains were identified via ribotyping and characterized in terms of growth rate and lipid production. 13 different known genera were identified, with the distribution analysis showing Chlorella as the most abundant fresh-water known genus (22.64%), followed by Chlorocystis (13.21%). Several microalgae strains belonging to the same classification showed significant genotypic diversity. Furthermore, several novel strains were identified (20.75%). Furthermore, several novel strains were identified. Growth rate analysis evidenced a thermo and halotolerant Nannochloris isolate QUCCCM31 able to tolerate 45°C and wide salinity range 35–100 ppt. Determination of lipid content and lipid profiling indicated the presence of promising strains for biodiesel production such as Nannochloris sp. (strain QUCCCM31) with a promising FAME profile for biodiesel production. This strain also produced nervonic acid, a C24:1 straight chain fatty acid of high pharmaceutical potential.

      Our results show heterogeneity in the Qatar Culture Collection and highlight the presence of Nannochloris sp., strain QUCCCM31, very promising for biodiesel production. The presence of the nervonic acid in the FAME profile increase amply the importance of this strain and enlarge its application for pharmaceutical purposes.

    • New Fault-Tolerant Control Approach for a Reconfigurable Grid-Connected PV System

      https://doi.org/10.5339/qfarc.2016.EEPP2603

      Power converters have become over the last decades an enabling technology for PV applications. As demonstrated by scientific literature on the subject, current research efforts are directed toward the use of intermediate solutions between fully centralized and totally distributed (one inverter for each panel or strings of panels) PV grid connection architectures, for cost, reliability and maintenance concerns. Within this trend, topologies of utility scale PV inverters are moving towards Multi-Level Inverters (MLI), which provide better power quality, lighter passive filtering components, and potential to eliminate bulky line frequency transformers. However, in high performance grid-connected PV systems, the failure of the power electronics converters has very serious consequences on the overall system operation. In view of an optimal utilization of the generated electrical power and as per the general fault-tolerance requirements, deploying a power electronics converter capable of continuing to operate effectively in the presence of any single point failure is essential for such as systems. A large-scale solar plant needs to tolerate short-term malfunctions while maintaining the inverter connected to the grid and eventually provide grid support.

      One of the main advantages of Cascaded H-Bridge (CHB) MLI is the modularity. A CHB inverter employs many partially separate power modules (cells). If these cells equipped with a bypass switching device (external switch), then if one of the power modules fails it can be bypassed and operation can continue at reduced capacity. This even allows the faulty cell to be replaced by a new one without turning off the system. However, bypassing a module reduces the voltage and power available from the inverter. Then, the problem becomes how to obtain the highest power level with the remaining operative cells.

      Moreover, the association of a quasi Z-Source (qZS) network with a CHB MLI was deeply investigated in the last decade for grid-tied PV systems. This single-stage mix-topology is characterized by high-quality staircase output voltage with lower harmonic distortions, independent DC-link voltage compensation with the special voltage step-up/down function in a single-stage power conversion, and independent control of the power delivery with high reliability.

      By taking advantage of the high CHB inverter's modularity and flexibility of the qZS network in controlling the DC-link voltage, this research work proposes a new fault-tolerant control strategy for a reconfigurable grid-connected PV system. The system under study consists of a three-phase sixteen-cell CHB inverter where each module is fed by a qZS network (Fig. 1). The proposed combined controller achieves grid-tie current injection, DC-link voltage balance for all qZS-CHB inverter modules, anti-islanding protection, and fault-tolerant operation. The fault-tolerance feature is explored and discussed for two modulation techniques, which are the Level-Shifted Pulse Width Modulation (LSPWM) and Pulse Width Amplitude Modulation (PWAM). The proposed strategy can be easily implemented without extra hardware requirements. It takes into account key crucial factors for high-efficiency and reliability grid-connected PV systems such as; cost reduction (selection of high efficient and high performing qZS-CHB MLI topology), high power quality (grid current injection with unity power factor and low harmonics distortion), active anti-islanding protection (according to grid codes), and fault-tolerance (continuous operation during malfunction of some system components, which leads to the system reconfiguration). The fault-tolerant design is taking advantage of the large number of redundant switching states for the same output voltage level, which characterizes the selected cascaded topology. However, one can note that this redundancy is effective only for the intermediate levels output voltages, while the extreme levels (highest and lowest levels) are achieved by only one switching state. Accordingly, the proposed approach offers circuit reconfiguration (based on a measurement based fault detection strategy) and voltage stress adjustment to achieve a balanced line-to-line voltage when a fault occurs.

      Moreover, Battery Energy Storage Sources (BESS) are used as additional source of energy to support the grid at fault times. At normal operating conditions, the BESS are used to store the excess power available from the PV to avoid the over voltage state. At fault conditions, the BESS could be used to provide the amount of power lost because of the failure of one or more of the inverter modules.

    • Removal of Lead Ions from Aqueous Solutions Using Polyaniline Polystyrene Nanocomposites

      https://doi.org/10.5339/qfarc.2016.EEPP2605

      Background and objectives

      Water pollution is an issue of grave importance worldwide, especially in countries that boast of a large number of industries. High concentration of heavy metal ions such as lead, nickel, etc are often found in industrial waste water and can have adverse affects on human health. Over the years a variety of methods, both physical and chemical ones, are reported to have been used for removal of heavy metal ions from water such as filtration and advanced oxidation [1, 2], etc. Adsorption is among the most widely used techniques due to its simplicity, reasonable operational conditions and cost-effective nature. The primary physical property of any absorbent is its surface area and structure. PANI is used due to the presence of primary and secondary amines functional groups which absorb heavy metals. However, due to poor solubility of PANI in common solvents it is made into composite with polystyrene which has strong mechanical properties. In this study a PS/PANI nanocomposite was prepared using the casting method; the composite was then investigated for its heavy metal ion absorption potential.

      Methodology

      PANI is obtained using dispersion polymerization by the usual technique defined in the literature [14, 15]. In order to prepare PANI/PS a mixture of toluene and sulfuric acid is used to get the composite. 0.05 g polystyrene, 0.95 g PANI mixed in 13:13 ml sulfuric acid and toluene solution and stirred at room temperature for 4 hours. The composite is kept on petri disc overnight and dried samples were heated at 50°C for 3 hours. Sulfuric acid was removed by washing the precipitate with distilled water and then dried again at 50°C for 3 hours to obtain the desired composite.

      Results and discussions

      &

      The morphology and structure of the obtained nanocomposite was studied by Scanning electron microscopy (SEM), and the functional groups were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The SEM images of pure PANI and PANI/PS composite are shown in Fig. 1 (a–b). The SEM image of pure PANI doped with HCl shows a predominantly fibrous morphology with fibers of uniform diameter of 93 nm. However, PANI/PS composites show very different morphologies. PANI/PS images show some nanoscale structures where PS are coated on the surface of PANI nanofibril structure. From the SEM images, it is clear that PANI/PS composite shows presence of a large surface area required for adsorption.

      Figure 2 shows the FTIR spectra of pure PANI, pure PS and PANI/PS composite. FTIR spectroscopy is a powerful tool for analyzing the molecular structure and the chemical interactions of the constituent polymers. The appearance of new peaks in the composite FTIR spectra along with changes in existing peaks directly indicates the chemical interaction between polymers. The obtained values are in good agreement with theoretical prediction.

      Table 1 tabulates the adsorption results of pure PANI and PANI/PS composites. From the results, it is clear that PANI/PS composites show the best removal efficiency because of the presence of high surface area due to its fiber morphology. Therefore, the remaining adsorption studies are done only on PANI/PS composites. The following sections describe the effect of contact time, pH, metal loading and composite dosages of the PANI composites on the removal efficiency of Pb from aqueous solution.

      The effect of time on the adsorption process of PANI nanocomposite was obtained by plotting the removal efficiency of Pb against time (Fig. 3). For the solution containing 50 ppm of Pb the maximum adsorption was reached in a short period of time and the composite adsorbed approximately 90% of the metal ion. The kinetics of the uptake of metal ion is related to the explicitness of the interaction between the metal ion and the polymer composite matrix.

      The pH of the solutions showed significant effect on the adsorption process. The effect of pH on the adsorption process of nanocomposite is represented in Fig. 4, where the adsorption coefficient was determined over the pH range 2–9, using 0.2 g PANI nanocomposite and 50 ppm Pb solution. It is clear that the maximum adsorption of metal ion took place for the solution with pH 2–6, and decreased at higher pH values. In our study, the pH of the prepared Pb solutions were adjusted to pH 5.

      The study of initial metal ion concentration on the sorption characteristics of the polymer nanocomposite is analyzed in the concentration range 30–100 ppm of the metal ion. The adsorption, as it can be seen in Fig. 5, is increasing rapidly with the increase in the initial concentration of Pb until 70 ppm. Beyond this concentration, the rate of increase in the adsorption is slow most probably because the adsorption sites are already saturated.

      Figure 6 illustrates the effect of PANI composites weight on the adsorption of metal ions. Varying amounts (0.1–0.5 g) of sorbent are added in 100 mL 50 ppm Pb solution under optimized conditions. From the graph, it is obvious that as the adsorbent concentration increases the removal efficiency of Pb in PANI/PS composite also increases. This is because the increase in adsorbent concentration provides greater surface area for adsorption and as a result it can hold more metal particles.

      Conclusion

      This work illustrates the preparation and adsorption property of pure PANI and PANI/PS composites. The synthesis of PANI nanocomposite has been successfully performed by in situ polymerization method and the incorporation of the PANI in PS was confirmed by FTIR. The SEM images of PANI and its composites confirmed the nanometer size range of PANI fibers. Adsorption performance of PANI and its nanocomposites has been studied for the removal of Pb from aqueous solution. Among the two adsorbents, PANI/PS shows 95% removal efficiency. The adsorption capacity of PANI/PS for Pb increases with initial metal concentration and composite dosages. Maximum adsorption was observed for pH 5, hence all the measurements are done at that pH. In conclusion, PANI/PS nanocomposite could be a good candidate for efficient Pb-removal from wastewater and for the deep-purification of pollutant water.

      References

      [1] S. S Madaeni, Y. Mansourpanah, Filtration & Separation, 40(6) (2003). 41–46.

      [2] T. Kurbus, Y. M. Slokar, A. M. Le Marechal, D.B. Voncina, Dyes and Pigments, 58(2), (2003) 171–178.

      [3] J. Stejskal, R. G. Gilbert, Polyaniline. Preparation of a conducting polymer, Pure Appl. Chem., 74 (2002) 857–867.

      [4] N. Gospodinova, L. Terlemezyan, Conducting polymers prepared by oxidative polymerization: polyaniline, Progress in Polymer Science, 23 (1998) 1443–1484.

    • Utilization of Two Microalgae Species, Synechococcus sp. and Cheatoceros sp., for Aquatic Toxicity Assessments in the Qatari Marine Environment

      https://doi.org/10.5339/qfarc.2016.EEPP2609

      Microalgal bioassays are currently used worldwide to help assess the impacts of contaminants on aquatic ecosystems. Algae are particularly important to such assessments because they represent the basic trophic level of the aquatic food web and contribute to ecosystem biodiversity. Toxicological impacts to these species may have follow-on effects (e.g., depletion of food source) on higher trophic levels and subsequent biodiversity consequences. ExxonMobil Research Qatar in collaboration with Qatar University Environmental Sciences Center and the Ministry of Environment are currently conducting researchto understand the impact of several water borne contaminantsto species of microalgae found in the Qatari marine environment.

      The two algal species used in this study included Synechococcus sp. which is a unicellular cyanobacterium that is very widespread in the marine environment and are preferentially found in the upper well–lit surface waters. The other species, Chaetoceros sp. is a centric diatom and is abundantly found in Qatari seawaters. Chaetoceros is a highly diverse diatom genus and has been described as the most dominant phytoplankton group in the ocean, in general. They play an important role in various marine ecosystem as a preferred food source for zooplankton and invertebrate larvae.

      Two microalgal species were isolated from the Qatari coastal watersand cultured in the laboratory. The cultures were maintained at 22 ± 1.0°C, under a 14 h:10 h/light:dark cycle provided by cool white fluorescence light (7000 ± 10% lux), in nutrient-enriched synthetic seawater (F/2 medium) at pH 8.0 ± 0.5 and salinity 40 g/L. The effect of abiotic factors such as salinity and temperature on the growth of both species was also investigated during culture development. Salinity effects were studied in therange of 25 to 45%. The results show that both species are euryhaline - that is, able to grow at all tested salinities – with best growth achieved at 30 and 40%. Both species were subsequently tested for tolerance to temperature ranging between 16 to 38°C,at both 30 and 40% salinities. These temperature experiments show that the highest growth rate was observed in cultures at 30°C and salinity 30%. Similar results were obtained at 30°C and salinity 40%. The lowest growth rates were observed at the lowest temperatures, while a decreased rate was also observed at the highest temperature.

      Acute (24 hr) and chronic (72 hr) toxicity tests were carried out on both microalgae species, with copper chloride which is widely used as a reference toxicant. Tests were performed using copper chloride at concentrations ranging between 0.05 and 0.75 mg/l. The test endpoints included: cell division rate inhibition, light-scattering properties of algal species, chlorophyll a fluorescence and esterase activity. Results for Synechococcus sp. and Cheatoceros sp. show a dose-dependent response to contaminant exposure. Consequently, it is apparent that both species may be considered as model test species for use in toxicity assessment and serve as akey component in a battery of toxicity tests with other native Qatari marine organisms. In particular, the toleranceof these microalgae species to fluctuations in salinity and temperature make them an ideal species to further explore the impact of potential effects of toxicants in Qatari waters.

    • Development of Green Inhibitors to Prevent Hydrates Formation, Protect Environment and Reduce Energy Cost in Oil and Gas Industry

      https://doi.org/10.5339/qfarc.2016.EEPP2611

      Gas hydrates are identified as ice-liked solid, crystalline compounds having polyhedral water cavities, where gas molecules get trapped during operation under high pressure and low temperature condition. These hydrates have a tendency to completely block the pipelines and can cause major operations shutdown, leading to large economic losses and causing high safety risk in transmission pipelines. Thus, annually the oil and gas sector spends over 100 million US $ on purchase of chemical inhibitors that can help to prevent hydrates formation in subsea lines.

      These inhibitors are classified into two separate categories, the thermodynamic and kinetic inhibitors. The thermodynamic inhibitors act by shifting the hydrates formation temperature and the kinetic inhibitors act by shifting the hydrates formation time. Currently, the thermodynamic inhibitors like Methanol and Methylene ethylene glycol (MEG) are mainly used in industry. These inhibitors are highly flammable and cannot be disposed of easily into the environment. They are required in bulk quantities (>30 wt%) and separate facility is needed for their storage and treatment process. This increases the overall energy cost and leads to major environmental disposal issue. Therefore, there is a high demand for inhibitors that are environmentally friendly and cost effective in oil and gas sector.

      Ionic liquids (ILs) are salt like compounds that have received attention due to their environmentally friendly, recyclable and non-flammable nature. These ILs have potential to prevent hydrate formation and they can act as both thermodynamic and kinetic inhibitors simultaneously. In this work, the Pyrrolidinium based ILs have been tested as gas hydrate inhibitors and synergistic compounds (Syn) are added with these ILs to improve their overall effectiveness. For the first time, the thermodynamic and kinetic study on ILs has been conducted using high dosage mixture of ILs + Syn on methane rich gas mixture to check their effectiveness in preventing gas hydrates formation.

      All the experiments are performed using a high pressure rocking cell assembly supplied by PSL Systemtechnik GmBH, at different pressures ranging from (40 to 120) bars. According to the tests results, we have evaluated that the mixtures were able to prevent hydrates formation by providing a temperature shift of up to 2.2°C at low pressures and by delaying hydrates formation time by (6 to 14) hours.

      These results confirm the dual inhibition behaviour of these mixtures, as they were able to shift hydrates formation temperature and delay hydrates formation time simultaneously. The results were also compared with widely known industrial inhibitor methanol and only a difference of 0.5°C was observed. Thus, this research provides an innovative approach towards development of environmentally friendly inhibitors and to reduce energy cost in the oil and gas industry.

    • Buildings Construction and Maintenance Role in Urban Pest Management

      https://doi.org/10.5339/qfarc.2016.EEPP2614

      The major threats to community health were recognized as coming from poor housing, poor management of sewage and drainage, foul air in industrialized towns, unsafe drinking water, and inadequate control of pests.

      Increasing pest infestation in urban areas is now a reality. The reliance on the use of chemical pesticides leads to negative results. Use of clean ecological methods must be the strategy of the future. Pests are attracted to our buildings to satisfy their needs which include food water and shelter. The development of building designs (green buildings), offers intriguing opportunities for use in future urban pest control by preventing pests from invading our buildings and enjoy the available food and shelter.

      A survey was conducted including 150 houses in Rayyan municipality with the aim to investigate the buildings defects which play a role in pest infestation. The results revealed that more than 50% of the buildings inspected are having defects which attract urban pests to the buildings. These defects include the presence of unsealed electrical and water pipes entry points to the buildings, sewage water manhole defects, cracks and crevices, gaps between floor tiles, doors and windows gaps. More than 60% of the buildings have defects in sewage water manholes include broken covers, manholes not built according to the standard specifications. More than 90% of the manholes are not equipped with valves. The results also indicated buildings with defects are more likely infested with pests like cockroach and ants. House owners questioner, revealed that, 73% of them believe that chemical control is the best method of control and they don't think that sanitation and maintenance will reduce pests population.

      It is clear from the results that construction and maintenance can be used as an important tool in urban pests management by preventing pests entry and survival inside our buildings.

      The survey results showed that effective pest management depends on more than just a skillful pest control operator because the conditions that allow the pests to have access to the buildings and satisfy their needs and requirements are under the control of other individuals for examples building designers, electrician, plumbers. Buildings managers, owners residence are also involved in the pests management program because sanitation is a major factor in the pest prevention program.

    • Qatar Culture Collection of Microalgae: A Sustainable Source for Biodiesel Production and Omega Fatty Acid Compounds

      https://doi.org/10.5339/qfarc.2016.EEPP2624

      Microalgae are photosynthetic microorganisms that can grow in different environments (sea water, fresh water, waste water soil, rocks…) and under various conditions (Light, pH, temperature, salinity…). During their phases of growth, they produce a variety of metabolites such as lipids, proteins and carbohydrates in large amounts over a short period of time. These metabolites can be processed into both biofuels and other useful bioproducts. Microalgal lipids can be converted to biodiesel via process called transesterification. The use of biodiesel will decrease the emission of harmful gases, which can help in reducing the greenhouse effects and global warming. It is nontoxic, biodegradable and has the potential to replace the conventional diesel fuel. The microalgal lipids extract can also constitute a natural source of active compounds offering a variety of nutraceutical and pharmaceutical applications.

      In the Algae Technologies Program at Qatar University, a Culture Collection of Cyanobacteria and Microalgae (QUCCCM) has been built and maintained in the liquid nitrogen. This culture collection contains more than 200 strains isolated during different periods of the year and from various places in Qatar. In this work we present the results of 8 marine green algae belonging to 3 different microalgal major groups: Chlorocystis sp., Nannochloris sp and Tetraselmis sp.

      The strains collected from different Qatar coastal places were screened for their growth rate, amount of total lipids as well as their Fatty Acid Methyl Ester (FAMEs) profiling. Culture was done in liquid F/2 medium at 300 C for a period of 15 days, after which algae were harvested for the determination of total lipids. A one step transesterification process was used to derivitize the intrinsic lipid into fatty acid methyl esters and the individual components were identified against known standards. The fatty acid profiling was obtained using a GC-FID.

      The comparative analysis of the QUCCCM isolates growth rate showed that Nannochloris sp. is the fastest growing isolate with a maximum value of 1.013 day-1. In terms of lipid contents, the results indicate a variety of the amounts. Nannochloris sp. showed the highest amount of total lipid (28.5%) followed by Chlorocystis sp. isolates with a total lipid amount of (19.5–21.5%) and later comes the Tetraselmis sp. strains with a total lipid content of (17.8–20.3%). The GC analysis showed a diverse range of FAMEs produced. All the strains screened contains the important FAMEs suitable for biodiesel production (C14, C16 and C18). The good growth rate of these strains along with their lipid content and profile make them competitive for a viable algal biofuel technology comparing to the terrestrial oil crops which need longer time to grow and present lower amount of lipids (Weyer et al., 2010). In addition, we observed the presence of the omega-3 and 9 long-chain polyunsaturated fatty acids (LC-PUFAs), such as eicosapentaenoic (EPA, 20:5 n-3), docosahexaenoic (DHA, 22:6 n-3) and Nervonic Acid (C24:1 n-9) acids, which have a high commercial value and are known for their beneficial effects on human health.

      Microalgae, Lipid, Fatty Acid Methyl Ester, Biodiesel, LC-PUFAs.

    • Metagenomic Approach to Explore Microbial Communities in the Rhizosphere of Date Palm

      https://doi.org/10.5339/qfarc.2016.EEPP2641

      Microbial communities in the date palm rhizoshere can play a vital role in the development of the palm and its health. Using the metagenomic as a tool can help in exploring these microbial communities in searching for microorganisms with potential for agricultural practices.

      Samples (roots and soil) were collected for metagenomic analysis from 12 date palms (khalas cv) growing at Roudat Alfars Research Farm of the Ministry of Environment. Sampling were done for the second time three month after fertilization of the palms. DNA was extracted and PCR were carried out for the variable regoins v1-v3 of the 16S rRNA gene. The amplified fragment were sequences using Next-Generation Sequencing (NGS) in two directing. Assembly of the reads and analysis were done Using mothur software Version 1.36.1.

      Results showed the presence of 13 bacterial phyla. Fertilizer has positive effect on increasing the presence of most of these phyla. A strong presence of cyanobacteria were observed followed by Proteobacteria then Actinobacteria in most samples. Cyanobacteria showed dramatic increased (in some samples more than 60 %) after fertilization. Cyanobacteria is known of their potential for atmospheric nitrogen fixation to ammonia (NH3), nitrite (NO2) or nitrates (NO3). Such process can act as an additional source of nitrogen for date palms.

      Also the analysis reviles the presence of Arthrobacter which is one of the main components of the soil microbes. It has the potential to reduce hexavalent chromium level in contaminated soil as well as degrades the 4-chlrophenol. Further investigation is needed to assess their potential as biodegradation agent.

      The following step is to isolate and characterize these bacteria as well repeating the metagenomics analysis after one year to determine the persistence of these microbial communities in the date palm orchard.

    • Modeling Risks of Urban Heat Island (UHIs) and Microclimate Change in Doha City Using Geoinformatics

      https://doi.org/10.5339/qfarc.2016.EEPP2644

      The economic boom that has taken place in Qatar in the last few decades has resulted in rapid population growth, urban expansion and change in life-style. Qatar Gross Domestic Product (GDP) has increased from 5.05 billion USD in 1986 to 211.8 billion USD in 2014. At the same time population has increased from 0.4 million in 1986 to 2.17 million in 2014. Urban expansion was and the accompanied modern urban life-style was necessary to accommodate this rapid population increase. Doha City has had the biggest share of urban expansion in the country.

      Recently, Doha faced a huge urban development and urban expansion in a short period of time. The modern urban designs in the city and the material used in the construction have changed the land surface albedo and the Land Surface Temperature (LST) in city. With this urban expansion, the Urban Heat Island phenomenon has become more noticeable between the urban center and the suburbs. Changing of landscape in the city due to the construction of roads and buildings has increased the surface temperature, as paving and building material replaces the Earth's natural surface causing surface compactness. Surfaces that were once pervious moist have become impermeable and dry. Open land and vegetation are replaced by buildings, roads, and other infrastructures and surfaces with high heat capacity, which impacted and created microclimates. This impact is due to the fact that many surfaces and asphalt absorb heat during the day and releases it during the night.

      Anthropogenic heat is one of the main causes of UHI in cities. The main sources of this heat include cooling and heating buildings, industrial processes, and transportation (highways, airports,..etc). Other causes of UHI are: air pollution; surface waterproofing; thermal properties of fabrics; and surface geometry.

      Urban heat island and temperature increase have a negative impact on the environment and on human health. Increased temperature also increases energy demand, air pollution and water shortages.

      This study uses remotely sensed data (high resolution satellite images) to highlight the urban expansion in Doha and the expansion of the UHI phenomenon as the city expands. Multi-date images from Enhanced Thematic Mapper (ETM) sensor on board Landsat Satellite were classified using supervised and un-supervised classification techniques to accurately identify and map the urban expansion in Doha. The classification results were verified and tested. Support Vector Machine supervised classification provided the most accurate classification of urban areas.

      In addition to the classification of the images, Thermal Bands of the same Landsat ETM images were modeled to calculate LST images for Qatar using Planck's function:

      T = K_2/In([K1*ϵ]/[CV]_R1+1)

      Where: T is degrees Kelvin

      K1 & K2 are satellite sensor constants obtained from the image metadata

      CVR1 is cell value as radiance

      ϵ_is emissivity (typically 0.95)

      The LST images show higher LST in the urban areas than in the desert suburbs by considerable margins especially in compacted areas, such as asphaltic roads and airports.

      This study also looked at the changes of urban fabrics over time and their land surface temperature Varian's in Doha. These variations in LST within the city and between the city and the desert suburbs create microclimates. These LST images could be used for the identification of different micro-climates within Doha. This micro-climates identification is very important to town planners, The results could also be used for air quality, solar energy and land-use planning studies.

      This study made some recommendations on how to reduce the UHI and increase in temperature phenomena by introducing Green Building technologies and green positive road network, and the interlocution of more green spaces in the cities.

    • Enhancing the Remediation Capacity of Mercury Ions from Fluorescent Lamp Using Roasted Date Pits and Its Modified Forms

      https://doi.org/10.5339/qfarc.2016.EEPP2658

      One of the most toxic heavy metals in the environment is mercury (Hg). However, it still has major uses in various industrial and agricultural applications; leading to localized mercury pollution. There has been an increase in the number of used fluorescent lamps compared to incandescent bulbs. Mercury is being used in fluorescent lamps in the elemental form where it can be vaporized under high pressure. The elemental form of mercury is also lipid soluble and can pass through both brain barrier and the placenta which can cause neurological disorder. Due to its harmful effect, the spent fluorescent lamps (SFLs) are being classified as hazardous wastes where mercury may leach and contaminate soil and groundwater. For these reasons the fluorescent lamps should be treated to reduce potential Hg toxicity or to use other components after recycling; e.g. glass and aluminum cap.

      Various extraction methods are available in the literature. However, in this project, two methods of extracting mercury from SFL were performed to assess their efficiency: acid extraction and microwave digestion. It was shown that the acid extraction only, using different acids ratios, were not able to remove all mercury from phosphor powder. However, the combination of acid extraction with a microwave digestion enhanced the efficiency of mercury extraction by more than 90%.

      Physicochemical treatment such as adsorption is also viewed as one of the easiest, safest, adaptable, and cost-effective physical chemical treatment methodologies in remediating toxic metals from aqueous medium. Though, the growing costs and environmental concerns linked with the commercial adsorbents has steered a new research orientation, which intended at developing low cost adsorbents that are produced from waste materials which are natural and renewable resources. Date pits as agricultural waste materials have been effectively employed as an adsorbent for remediating various heavy metals from aqueous media and normally with the benefits of being low cost, naturally available, and environmentally friendly. Chemical modifications processes were also be employed to improve their remediation capacity and selectivity.

      The current study, therefore, investigated the effect of different modification treatments on the roasted date pits (RODPs) surface chemistry and therefore; enhancing the mercury remediation capacity. The RODPs was grafted with organosilane to remediate Hg2? from the extracted fluorescent lamp solution. The remediation of Hg2? from the extracted fluorescent lamp solution was investigated in a batch isotherm remediation system pertaining to pH, concentration, particle sizes, and contact time.

      The SFLs of different brands were collected from throughout Qatar. Two main types of SFLs were collected and tested; the T8 and T12. The SFL were scratched and the powder inside was carefully collected by brushing the inside of the lamps (approximately 100 g have been collected). Various reagents and materials were used for the mercury extraction experiments such as HCl, HNO, and HO. The instruments and methods mainly adapted in these experiments were Cold Vapor Atomic Absorption Spectrophotometer (CVAAS) for the mercury analysis, incubator shaker to maintain constant shaking with temperature, microwave for the extraction enhancement, and oven. In the experiments, the ratios of HCl, HNO, and HO as extracting agents were carefully chosen to achieve the maximum exactable mercury.

      The collected date pits were roasted at 150°C for 5 h and the sulfur-modified roasted date pits was carried out to investigate the adsorption enhancement after modification. In order to study the impacts of different pH values on the adsorption, the FTIR spectra of the RODP and RODP at different pH values were recorded. The FTIR measurements were performed over 4000-400/cm. Scanning electron microscope (SEM) was also used to evaluate the surface morphology of the adsorbents using the JEOL model JSM-6390LV.

      After determining Hg2+ concentration in the extracted SFL solutions, various initial Hg2? concentrations were prepared. The residual Hg2+ in solution was analyzed after adsorption onto RODP. Different key parameters will also be performed such as the effect of pH, mass, and the solution temperature.

      From the initial results, we can conclude that the highest Hg adsorption occurred at pH 6 with almost 80% adsorption value. Moreover, at pH 8 and pH 10, the adsorption decreased with an average Hg concentration of 3.5 and 8.01 ppm, respectively. This decreasing in the adsorption capacity is due to the formation of mercury (II) hydroxide Hg(OH) which forms a precipitation; resulting in decreasing the adsorption. However, pH 2 and pH 4, have average concentration of mercury equal to 18.8 and 18.3 ppm, respectively, which is very high concentration and it is over range.

      From the FTIR results we can determine the functional groups of the RODP which can determine the reactivity of the RODP towards mercury. According to the results obtained from CVAAS that pH 6 is the best pH for the adsorption process, functional groups found in the RODP having pH 6 are mainly hydroxyl and carboxyl acid which means that these functional groups have the highest ability to adsorb mercury more than other groups. This paper was made possible by UREP grant # (UREP17-066-1-004) from the Qatar national research fund (a member of Qatar foundation). The statements made herein are solely the responsibility of the author(s).

    • A Novel Forward Osmosis Desalination Process for Irrigation and Industrial Purposes

      https://doi.org/10.5339/qfarc.2016.EEPP2659

      The availability of clean water for agriculture has become a growing concern because of the increasing global water scarcity. Agriculture sector already accounts for around 70% of the total water withdrawals in the world whereas domestic and industrial water use is about 10% and 21% respectively. Desalinated water has high quality and irrigating with desalinated water would result in 24% increase in the crop yield and assist a 45% reduction in the current water irrigation volume simultaneously. However desalination is an energy intensive process and an expensive option. The current membrane and thermal desalination systems have many limitations, including high energy consumption and capital cost, especially for thermal methods, coupled with negative environmental impacts due to the discharge of brines and chemicals. Forward Osmosis (FO) promises to overcome most of the practical difficulties in conventional RO desalination process such as fouling, scaling, chemical treatment and high power consumption. In addition, FO process gives higher throughput with minimal environmental impact including minimal chemical additives and rejection of waste stream. Forward Osmosis (FO) process has the potential to increase the availability of freshwater both in coastal areas with limited resources and in areas where seawater, salinized groundwater and municipal wastewater are available. The novelty of FO process lies in using natural osmosis as a driving force for water to move across a semi-pearmeable membrane from a solution of low osmotic pressure (seawater) to a solution of high osmotic pressure (DS). The choice of draw solution (DS) has a large impact on the performance and viability of the FO process. The draw solutes should be able to generate high osmotic pressures and be completely regenerated using simple and energy efficient techniques.

      This study presents a novel FO process for producing irrigation water using thermolytic draw solution. The main energy intensive stage in FO process is the separation of draw solute from the freshwater. In this research, the concept of employing liquefied gas compounds as a draw agent has been investigated among 137 gaseous compounds by determining their high solubility in water. In this process a liquefied gas as DS with high solubility in water resulting high osmotic pressure has been used. The DS could be separated from water by changing the operating temperature and or pressure allowing for an efficient and complete removal of the DS. The modified FO process operates at low hydraulic pressure

    • The Indigenous Qatari Marine Copepod, Euterpina Acutifrons: A Promising Marine Invertebrate Model Organism for Aquatic Eco-Toxicological Studies

      https://doi.org/10.5339/qfarc.2016.EEPP2669

      An important objective of aquatic toxicological assessments is to evaluate the effects of water-borne toxic compounds on organisms which play a crucial role in aquatic communities. In marine ecosystems, copepods have a major impact on essential ecological processes: they exert grazing pressure on phytoplankton, and are a significant food source for several fish and macro crustaceans. Euterpina acutifrons, a harpacticoid copepod, is an abundant species in the Arabian Gulf, including the coast of Qatari peninsula. Its high content of poly unsaturated fatty acids make it a nutritionally superior live feed for larval fish in aquaculture, an industry developing fast in Qatar. With its ubiquitous distribution worldwide, inter-and intra-sexual dimorphism, well-defined life cycle, short generation time, and anamorphic developmental stages, this species meets many of the criteria to become a suitable model for toxicity studies. The present study defines protocols for establishing a successful laboratory culture of Euterpina acutifrons and for its acute toxicity testing with four toxicants. This study will add to the refinement of a suite of bioassay techniques being developed at ExxonMobil Research Qatar using a gamut of vertebrate and invertebrate indigenous marine species.

      A sustainable culture of Euterpina acutifrons was established by rearing ovigerous individuals of this native species isolated from local waters. A few gravid individuals were used to include the natural genetic variability in the population. Through a series of planned trials, a simple protocol was established for culturing and maintaining the species in the laboratory. A temperature of 22 ±  2°C, photoperiod of 12 h light: 12 h darkness, salinity at 40 ±  2 ppt, and a 3:1 microalgal mixture of Chaetoceros sp. (diatom) and Synechococcus sp. (blue-green algae) as food, fed twice every week, was found to give an optimum survival and fecundity in the laboratory.

      In order to investigate the efficacy of this species as a ecotoxicity test organism, a series of static, acute 24 h and 48 h toxicity tests were performed using three widely used reference toxicants, sodium dodecyl sulfate (SDS, an anionic surfactant used widely in cleaning and hygiene products), 3, 4-dichloroaniline (DCA, a metabolite of several herbicides), and Zinc (heavy metal) at 22 ±  2°C. Impact of chlorine, an anti-biofouling agent used in industrial cooling waters globally, was tested in a semi-static set up, where chlorine dose was renewed at regular intervals. Similar-sized copepodite stages used for these tests were procured through laboratory culture synchronization. The 24 h/48 h LC50 values were calculated based on the end point of the tests, which was mortality or total cessation of mobility. The copepod showed dose-dependent responses and different sensitivity towards the four toxicants; toxicity ranking increasing from DCA, SDS, Zinc to Chlorine. The differences in toxicities can be attributed to different mechanisms of action of the four compounds. The sensitivity of this species compared favorably with other established marine invertebrate models for ecotoxicity testing. Given, the feasibility of culturing, continuous egg production throughout the year, and high reproducibility of the toxicity responses in this study, it is advocated to further explore the use of Euterpina acutifrons as a model organism to assess long- and short-term effects of potential water-borne contaminants in the Arabian Gulf.

    • Environmental Factors Affecting the Growth and Enzymatic Activity of Ceratocystis Radicicolathe Causal Agent of Black Scorch Disease on Date Palm

      https://doi.org/10.5339/qfarc.2016.EEPP2681

      Ceratocystis radicicola is a soil-borne pathogen (Wingfield et al, 1993) causing sudden death of date palm (Phoenix dactylifera) in USA and South Africa (Bliss, 1941; Lind & Smit, 1999). It also has been reported to be associated with date palm in Qatar causing black scorch disease (Al-Naemi et al., 2014). Environmental factors such as poor hygienic conditions, stressed palms or senescent tree parts contribute to increase the incidence of black scorch in date palm (Laville, 1966).

      Plant pathogens including fungi produce variety of enzymes that degrade plant cell wall. Fungi also secrete several molecular forms of hydrolases that attack the same substrate although they are different in isoelectric point and molecular weight. Extracellular enzymes secreted by fungi are able to macerate tissues and degrade cell wall components. Consequently, they must contain all enzymes related to the types of glycosidic linkages that are present in cell wall polysaccharides. The level of these enzyme activities correlates with the development of disease symptoms (Riou C et al., 1991). This study aimed to: (i) examine the influence of salinity and drought stresses on the growth of C. radicicola in vitro; (ii) study the enzymatic activities of xylanase, cellulase and pectinase in C. radicicola, (iii) examine the effect of various Carbon sources (sucrose, xylan, carboxymethyl cellulose and pectin) on C. radicicola enzyme activities; and (iv) investigate the effect of pH media on the fungal growth. For salt stress, 4 mm disc of C. radicicola was cultured in PDA or PDB media with different concentrations of NaCl (0, 0.26, 0.43, 0.60, 0.86, 1.03, 1.20 and 1.37 M). The culture was incubated at 25°C for 7–21 days under dark conditions. Rate of relative fungal growth on PDA was recorded and given the following scales (–: No growth, 1+ very minimal growth, 2+: minimal growth, 3+: moderate growth, 4+: heavy growth and 5+: very heavy growth). The mate of fungal growth on PDB was harvested every weak and fresh and dry weight obtained. Hemocytometer was used for spore counting and the number of spores is divided by 5 and multiple to 104 to obtain the total number of spores/ml.

      For drought stress, 4 mm disc of C. radicicola was cultured in PDA and PDB media with different percentages (0, 2, 4, 6, 8, 10, 20, 40 and 60%) of Poly Ethylene Glycol (PEG4400). The culture was incubated at 25°C for 8–10 days under dark conditions. The diameter of fungal growth on PDA was measured. The mate of fungal growth on PDB was harvested. Spores were counted by using hemocytometer.

      In case of enzyme activity assay, Czapek media was prepared where the carbon source was substituted with 1% of the following: carboxymethyl cellulose (CMC), sucrose, pectin or xylan. To optimize the fungus growth, pH media was adjusted at different levels (5.5, 6, 6.5, 7, 7.5 and 8). In addition, standard Czapek broth media was used as a control. Four mm discs of C. radicicola were inoculated in czapek media and incubated at 25°C for 8–10 day. Cultures were centrifuged at 5000 rpm for 20 min. and supernatants were used to examine xylanase, cellulase and pectinase DNS – enzymatic activities. The enzymatic activity was calculated using the following equation; Enzyme activity =  (standard factor ×  absorbance)/time of incubation (min); whereas standard factor =  (concentration (m mol/ml) of standard/absorbance at 540) ×  dilution factor. Spectrophotometer was used to measure the enzyme activity based on reduced sugar in the media. Results from salinity stress in vitro showed a clear growth of C. radicicola in PDB media with NaCl concentrations of 0.26, 0.43, 0.6, 0.86, 1.03 and 1.2 M during the first three weeks while no growth was occurred in PDB with 1.37 M. Radial growth of C. radicicola did not show any changes on PDA with 0.26, 0.43 and 0.6 M while fungal growth diameter decreased significantly under 0.86, 1.03 and 1.2 M concentrations to reach 4.9, 2.3 and 1.4 cm, respectively (Fig. 1). Number of spores was decreased by increasing NaCl concentrations from 1.4 ×  104 in control treatments to reach zero in 1.2 M.

      Growth of C. radicicola was tested under physiological drought stress using different concentrations of PEG4400 (0, 2, 4, 6, 8, 10, 20, 40 and 60%). C. radicicola was able to survive under drought stress regimes up to 40% in the first seven days while it failed to grow at 60% of PEG4400.

      Results of enzymatic activity assays showed that C. radicicola grow very well in czapek media supplemented with 1% both xylan and pectin as carbon sources while it showed weak growth in czapek media supplemented with 1% of CMC. On the other hand, C. radicicola did not grow in czapek media supplemented with 1% sucrose. Results also showed that both Xylanase and carboxymethyl cellulase had the highest enzymatic activities with 109 and 6.8 IU/ml, respectively when pectin was used as a carbon source at pH 8. Moreover, high pectinase activity was recorded (61 IU/ml) when pectin was used in the growth media at pH 7.5. When xylan was used as source of carbon, Xylanase showed high activity at pH 5. In standard czapek broth media, activities of xylanase and carboxymethyl cellulase enzymes increased by increasing pH while pectinase activity decreased. To study the effects of salinity and drought stresses on the growth of C. radicicola in vitro, the fungus was exposed to different salt and drought stress conditions. Our results revealed that C. radicicola was able to survive and grow up to 1.2 M NaCl during the first three weeks, while it could not grow at 1.37 M. Fungal growth diameter and number of spores were decreased by increasing NaCl concentration. Growth of C. radicicola was affected severly under physiological drought stress where it was not able to survive at 60% of PEG4400. Enzymatic activity assays showed that C. radicicola grow very well in czapek media supplemented with 1% both xylan and pectin as carbon sources while it showed weak growth in czapek media supplemented with 1% of CMC. On the other hand, C.radicicola did not grow in czapek media supplemented with 1% sucrose. Xylanase and carboxymethyl cellulase had the highest enzymatic activities when pectin was used as a carbon source at pH 8.

    • Vibration wave characteristics in Conventional and Periodic Drill string models

      https://doi.org/10.5339/qfarc.2016.EEPP2700

      Drill string models are of two major types- Conventional and Periodic. Conventional drill string models are widely used due to their simplicity in manufacturing and dynamics analysis. Drill strings are affected mainly by torsional, lateral and axial vibrations. The dispersive or propagative nature of these vibrations can only be analyzed by using periodic drill string models. Drill pipe makes up the majority of the drill string. In reality, at each end of the drill pipe, tubular, larger-diameter portions called the tool joints are located. Since the dimensions of the tool joint are negligible when compared to the drill pipe, conventional drill string models assume drill strings to be uniform structures. The tool joints in drill strings introduce a geometrical periodicity in the structure.

      A periodic structural component is comprised of a repeating array of cells, which are themselves an assembly of elements. The elements may have differing material properties as well as geometric variations. The periodic structures act as mechanical filters for the wave propagation. A material or geometrical change in the structure causes a disruption to the continuous propagation of vibration waves.

      There are three types of waves propagating in rotating structures: torsional, flexural (bending) and longitudinal. Of these waves, torsional and longitudinal waves are dispersive while flexural waves are non- dispersive. The proportions of the waves which are dispersed vary according to the Wavenumber. The wavenumber is a property of the wave and depends on the structural, material and geometrical properties of the wave guide. Waveguide is the medium through which a wave travels. The wave number, and hence the dispersion and propagation characteristics of waves can be tuned by varying the material and geometrical periodicity in the drill strings.

      This paper presents the vibration propagation and attenuation characteristics in conventional and periodic drill string models. The periodic drill string model is developed such that it can be easily scaled to a real drilling rig model. The research also features a laboratory setting which comprises a mini drilling rig and actual drilling samples. These features ensure robustness of the dynamics analyzed for the periodic drill string model.

      The research findings are analyzed under zero and non- zero borehole drill string interactions. Vibration information is collected from upper and lower parts of the drill string models to compare the propagation and attenuation characteristics. Proximity sensors are used for the data acquisition which is then analyzed using frequency and power spectrum graphs. The time and frequency domain vibration propagation characteristics are investigated for both the conventional and periodic drill string models. Laboratory testing analyzes (1) introduction of stop and pass band regions in frequency spectra by periodic drill string models, and (2) vibration attenuation in torsional and lateral vibration modes. The tests confirm the introduction of stop bands in frequency spectra for the periodic drill strings, while they were absent and had an all pass-band for conventional drill string models.

      The research opens up a new method of passive control of drilling vibrations- by introducing tool joint designs which could be tuned to efficiently dampen out the harmful vibrations affecting the drilling rigs.

    • Experiences and First Results from the EC Product Environmental Footprint (PEF) Pilot on Hot and Cold Water Supply Piping Systems in the Building

      https://doi.org/10.5339/qfarc.2016.EEPP2722

      The European Commission's Single Market for Green Products initiative proposes a set of actions to overcome the problems companies and consumers face with the diverse amount of environmental information and methods available on the market. Amongst the proposed actions are the establishment of a Product Environmental Footprint (PEF) methodology and a three year Pilot phase to develop product specific rules through a multi-stakeholder process. The aim of proposing the EU-wide PEF methodology is to measure the environmental performance of products and to encourage Member States and the private sector to take them up. VITO is involved in three building related pilots: hot and cold water supply piping systems in buildings, insulation materials used in buildings and metal sheets applied in buildings. In 2017 the Commission will make an in-depth evaluation of the results of this three-year testing period and the results of additional actions related to communication and recommendations. Based on this evaluation, the Commission will decide on further policy applications of the PEF methodology.

      PEF pilot on hot and cold water supply piping systems in the building

      The Pilot on hot and cold water supply piping systems, submitted by The European Plastic Pipes and Fittings Association (TEPPFA), the European Copper Institute (ECI), the Flemish Institute for Technological Research (VITO), the European Association of Plastics Manufacturers (PlasticsEurope) and the Plastics Recyclers Europe (PRE) is one of the Pilots accepted by the Commission for the three-years testing PEF Pilot phase. During the Pilot phase Product Environmental Footprint Category Rules (PEFCR) for hot and cold water supply piping systems need to be developed. The PEFCR helps directing the focus of future PEF studies on hot and cold water supply piping systems to the most important parameters, thus also reducing time, efforts and costs. To foster the development of a PEFCR, PEF screening studies have been carried out. The representative product used in these screening studies is a virtual product based on the market shares of PEX (cross-linked polyethylene), Multilayer (Polymer/Aluminium/Polymer) and Copper hot and cold water supply piping systems. The weighted PEF environmental profile shows that the most relevant life cycle stages, having a contribution of >10%, are the acquisition and pre-processing of the raw materials for pipes, fittings and other components, manufacturing of pipes together with the ‘end-of-life treatment’. Based on expert knowledge it has been decided to consider as important also the life cycle stages related to the manufacturing of the fittings.

      The PEF screening studies looked at 15 different life cycle impact categories. After normalisation of the results, the categories resource depletion (mineral, fossil), resource depletion water and human toxicity cancer effects are found to be the most important impact categories for the hot and cold water supply systems. Besides the above conclusions, the screening studies revealed that publicly available datasets for many processes and materials are missing. Moreover, the available data are often of poor quality which influences the outcome of the study. Also taking into account or not level III toxicity substances influences the outcome of the screening studies.

      Currently PEF supporting studies are performed together with specific producers of PEX, Multilayer and Copper piping systems for hot and cold water supply in the buildings. The PEF supporting studies needs to be compliant with any specific requirement included in the draft PEFCR that has been developed, comprising all environmental impact categories and having a full coverage in terms of life cycle stages and processes. The PEF supporting studies are based on existing products as currently sold in the European market. The goal of the PEF supporting studies is to support evidence to the PEFCR development and the intended audience. The studies will be carried out under the assumption that the result will be used to contribute to the development of a PEFCR that could support comparisons or comparative assertions intended to be disclosed to the public. The results of these studies will be used to test the pertinence and implementability of the draft PEFCR including, but not limited to, the identified most relevant environmental impacts, issues related to data collection and quality, verification requirements. Moreover, the uncertainty analysis carried out on the results of the the PEF supporting studies may contribute to the identification of appropriate performance classes (where relevant and appropriate).

      Presentation at the ARC conference 2016

      The presentation at the ARC 2016 conference will focus on the results of testing the PEF methodology as published by the EC in 2013, step by step. In addition the presentation will illustrate the application of the methodology and illustrate the assessment results of the screening studies. By March 2016 when the ARC 2016 conference will take place, it is expected that the first results of the supporting studies will be ready, so that we can also present first results on the outcome of these studies.

    • Preliminary investigations into the reproductive biology, in vitro fertilization and laboratory culturing of the Qatari Pearl Oyster (Pinctada radiata)

      https://doi.org/10.5339/qfarc.2016.EEPP2724

      The marine species Pinctada radiata is the most abundant pearl oyster found in Qatari waters; however, little is known about its reproductive biology, ecological importance and life cycle. This species has been harvested for many centuries primarily for natural pearls but also for edible flesh and lustrous shell. Wild stocks of P. radiata are now significantly threatened in the Arabian Gulf region as a result of both natural (e.g. extreme salinity, high temperatures, high evaporation rates and low flushing rates) and anthropogenic factors (e.g. rapid development of coastline areas, overfishing and heavy exploitation). Nonetheless, pearl oysters are a dominant component of the benthic community of the Qatari Coastal waters and are important ecologically as suspension feeders, as food and habitat for other animals, and as structural components of the substratum. Oysters filter prodigious volumes of water, capturing particles down to 5 microns in size and ingesting algae, zooplankton, bacteria and detritus. They are therefore exposed to both dissolved and suspended contaminants. Consequently, they are likely to be excellent indicators of potential contaminants in the Arabian Gulf and can be used for risk assessment and monitoring as part of an effective environmental management program.

      Prior to using the pearl oysters in toxicity testing, we investigated the reproductive biology of P. radiata and its in vitro fertilization. The oysters were collected from intertidal habitat at the Qatari coast and cultured in flow-through systems at a density of 2-3 oysters/L. They were divided into three equal groups and were placed every day into a feeding tank for 2 hours. One group was fed with a combination of two microalgae species and rice powder, the second group was fed the microalgae alone and the third group was fed rice alone. After 30 days, 3 oysters were taken from each group to check if maturation was achieved. Eggs from mature individuals were kept in different concentrations of ammonia solution for up to 2 hours to prime them for fertilization. Next, matured eggs and sperms were mixed at different ratios. The fertilized embryos were kept at 27°C and salinity of 40 PSU. Embryo development was followed under a light microscope.

      Successful fertilization was achieved with gametes obtained from oysters fed with mixtures of algae and rice (80%), rice alone (60%) and microalgae alone (20%). Fertilization occurred in treatments with 2% ammonia solution and a ratio of 8000:2000 sperm: egg. All stages of larval development were identified (in time) and noted for protocol development. Early development followed the typical marine bivalve pattern of trochophore, D-stage veliger, umbo stage, eye-spot stage, pediveliger, metamorphosis and newly settled spat. This took 3–4 weeks in total, depending on culture condition and food types. The successful in vitro culture and fertilization can provide both embryos and adults which can be used as indicator species to carry out toxicity studies. Future work will focus on examining the sensitivity of the P. radiata to contaminants of concern in the Arabian Gulf region. These efforts are important for assessing environmental risk in the Arabian Gulf and providing science-based tools for making management decisions.

    • Will Reverse Osmosis Replace Thermal Desalination in GCC Region

      https://doi.org/10.5339/qfarc.2016.EEPP2725

      Desalination is probably the only means for fresh water supply to countries in decertified climate. The majority of GCC counties rely on desalinated water for fresh water supply to major cities. Over 70% of the desalinated water in the GCC comes from thermal desalination plants including Multi Stage Flash (MSF) and Multi Effect Distillation (MED). The new trend in the desalination plant in the GCC is 30% Reverse Osmosis (RO) and 70% thermal. However, these percentages vary from one to another country depending on feed water quality and expertise. For example, Oman Sea has lower salinity than the Gulf water and hence Oman uses more RO for desalination than MED and MSF. This decision is also driven by economy as RO process less energy intensive and hence the produced water is less expensive as compared to thermal plants. On the contrary, Qatar and Kuwait use more MSF followed by MED due to the high salinity and low quality feed water. This is also because trials of RO in both Qatar and Kuwait were not successful because of the problems of membrane fouling and restrict pre-treatment requirements due to the quality of the water intake.

      The advantages of RO over thermal technologies are well known in terms of lower energy consumption and the cost of produced water; but are not yet taken advantage of in the GCC zone. One of the reasons is blamed on high feed water salinity and bad water quality; other reasons such as lack of experience, red tides and reliability are contributed to the dominance of thermal plants. However, field experience showed that good pretreatment and optimized RO design may overcome the problems of high feed salinity and bad water quality. Several RO plants, such as Fujairah in UAE, are good examples of a working RO technology in the harsh water environment. Good RO design includes design and optimization of both pretreatment and post-treatment. Field experience showed that most of RO plants failure was due to inefficient pretreatment which resulted in providing low quality water to the RO membrane that caused fouling. Fouling, including biological and scaling, can be handled once an efficient pretreatment process is available. Recent advances in pre-treatment techniques include the combination of Forward Osmosis (FO) with RO among other methods. Recent studies by the authors including commercial implantations have shown that the combination of FO with RO addresses the most technical challenge of RO process and that is fouling, which results in lower energy consumption and less chemical additives. Experience showed fouling in FO process in reversible, i.e. can be removed by backlashing while fouling in conventional RO process is irreversible.

      In this study, the feasibility of integrating FO with RO process for the desalting of the Gulf water in Qatar is presented. The results are expressed in terms of specific energy consumption, process recovery, produced water quality, chemical additives and overall process cost.

      The implementation of RO for desalination is not only reducing the cost of desalination but also the environmental impact. More R&D should be done to provide useful data about RO application and suitability for the Gulf water. The R&D should be focused on laboratory to market development of RO technology using rigorous lab scale and pilot plant testing program.

    • A New Class of Electrocatalyst Materials for Direct Methanol Fuel Cell Applications

      https://doi.org/10.5339/qfarc.2016.EEPP2736

      Direct methanol fuel cell (DMFC) has been attracting lots of attention as a power source for transportation, stationary and portable electronic devices due to the high energy density of methanol and ease of handling compared to gaseous fuels such as hydrogen and natural gas. However, the commercialization of DMFC is still limited due to some technical challenges such as methanol crossover and low methanol electro-oxidation kinetics. In order for fuel cells to be a feasible and viable option amongst clean energy technologies, innovations in the materials developments are required for efficient operation of fuel cells. Many efforts have been made in various research laboratories to develop high-performance catalysts that will enhance the methanol electro-oxidation. Compared to any single-metal catalyst, Pt has shown the highest activity for the electro-oxidation of methanol in an acid environment. However, Pt is expensive and during the methanol electro-oxidation reaction, COads and other organic intermediates such as formaldehyde, formic acid and methyl formate are formed on the Pt surface, which results in poisoning of the Pt catalyst.

      Many binary and ternary catalysts for methanol electro-oxidation have been investigated and reported in the literature, most of them based on modification of Pt with some other metal(s). The aim is to accelerate the oxidation of the intermediates and decrease their accumulation so as to improve the catalyst performance. Among the various catalyst formulations, PtRu alloy has shown the best results for the methanol electro-oxidation. Diverse methods have been used to prepare the PtRu-based catalysts for methanol electro-oxidation. Catalyst composition and method of preparation are known to immensely affect the physical property es and electrochemical performance of a catalyst. Thus, there is the need to use a carefully selected approach in order to prepare a catalyst with the highest attainable performance. Incorporation of transition metals into the PtRu catalysts to form ternary catalysts in order to improve the performance of the PtRu catalysts is one of the techniques attracting a lot of interest. In this work, a novel approach have been used for synthesizing a new class of electrocatalyst nanomaterials for electro-oxidation of methanol by incorporation nano-oxides of transition metals. The prepared nanomaterial catalysts were characterized using FESEM, BET surface area, EDX, FT-IR and XRD. The catalysts performance was studied using cyclic voltammetry and compared with the commercial Pt-Ru/C.

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