Qatar Foundation Annual Research Conference Proceedings Volume 2016 Issue 1

The growing energy demand across the globe has resulted in an increase in the deep water oil exploration activities which in turn has increased the risk of occurrence of associated accidental oil releases. Oil and Gas offshore businesses are important to Qatar's economy. Further, the country is heavily dependent on its marine water resources for fulfilling its potable water needs through the desalination process. So, it is imperative to safeguard the marine environment during an unfavorable accidental oil release, which essentially would put entire ecosystem into peril. Development of reliable models can assist in predicting the extent of damage caused to the environment and can further help in deciding the mitigating strategies during such events. The current research focusses on exploring the of capabilities of Multiphase Computational Fluid Dynamics (CFD) models in simulating various transport processes associated with deep water oil spills. The accidental release of oil in deep oceans results in formation of the plume. The interaction of inertial oil mass with surrounding water results in the formation of droplets which rises in the water column due to buoyancy. Dispersant addition is one of the preferred methods of oil spill remediation which causes the lowering of interfacial tension at the oil/water interface and under the action of local turbulence, it enhances the droplet disintegration process. In deep spill scenarios, droplets spend large amounts of time in the water column, hence, the dissolution process of soluble hydrocarbons which otherwise is detrimental to aquatic life, becomes important. The objective of this work is to develop integrated numerical models which can effectively guide us in predicting the fate of oil mass in such scenarios and help us is estimating the overall impact of such accidents on the environment. Before taking a leap into full scale modelling, it is imperative to grasp a good understanding of above mentioned transport processes at a more fundamental scale. Hence, in the first phase of this project, single droplet dynamics in quiescent systems were studied. We primarily investigated the effect of surfactant (the chief component of a dispersant), on the dynamics of a crude oil droplet rising in a stagnant column. Laboratory scale experiments were performed and a multiphase CFD model based on Volume of fluid method was developed to capture the shape dynamics of the droplet rising in a surfactant laden environment. To capture the subsurface dissolution of hydrocarbons from oil droplet, a unique experiment was devised wherein a binary organic mixture, representing a pseudo oil droplet comprising of volatile and non-volatile hydrocarbons, was employed to study the effect of unsteady mass transport on the overall dynamics of the droplet. Based on the experimental observations, correlations were proposed to estimate the mass transfer rate at various stages of droplet motion. A CFD model capable of evaluating concentration fields of the transported species in both dispersed as well as continuous phases, was developed by coupling VOF approach with species transport model. The above models were also employed to study the jet breakup dynamics in the laminar regime. The next challenge was to extend the applicability of developed models to large scale scenarios. Turbulence is inherent to oceanic environment and hence incorporating it into existing models becomes important. In a real deep spill scenario, a swarm of bubbles and droplets often interact with each other in a turbulent environment and this leads to occurrence of a sequence of coalescence and disintegration processes. The information on size of droplets serves as an important parameter for the evaluation of approximate rise velocities and overall mass transfer rates in the system. Thus, a model capable of predicting droplet size distribution can be employed for determining the fate of droplets in the event of accidental subsea releases. In current work, this objective was achieved by integrating traditional multiphase CFD models and turbulence models, with a population balance (PB) approach. The developed model was validated against the experimental observations reported in Johansen et al (Marine Pollution Bulletin. 2013;73(1), 327–335). Through this work, we were able to demonstrate the capability of an integrated CFD+PB model in analyzing the effect of dispersed (oil) phase flow rates, the presence of dispersants and the presence of air (introduced along with the dispersed phase) on the overall size distribution of oil droplets.

Due the movement of the sun throughout the day, the insolation level incident on the fixed panel surface varies largely. The maximum level of insolation occurs only around noon. This leads to the panel to be under-utilised. To maximise the utilisation of the panel during the day, mechanical solar tracking is used. This method not only increases the utilisation of the, but increases the power being extracted from the panel. Solar tracking using one axis tracking increases the energy yield from the solar panel by 40 percent.

Extended Abstract

During the span of a day the sun's movement has been shown in figure 1. As the day passes by, the level of incident solar radiation (insolation) changes. This change takes place due to position of the sun. The angle at which the sun's rays fall on the photovoltaic panel affects the insolation level available for the panel to convert into electrical energy. For the fixed panel, the sun's rays are not normal to plane of the panel most of the time. This causes the panel to be under-utilised. To extract more energy from the same panel, solar tracking is required. This follows the sun's movement thereby increasing the insolation level throughout the day. This increase in the insolation level is due to the fact that the angle between the normal to the solar panel and incident light is to be kept minimum.

Figure 1: Sun's movement throughout the day

The principle of a single axis solar tracking has been shown in figure 2. The solar tracking can be accomplished by four methods: active tracking, passive tracking, chronological tracking and manual tracking [1]. Active trackers measure the light intensity from the sun using light sensors which give signal to the controller and driving mechanism. Passive trackers commonly make use of a low boiling point compressed gas. This gas is filled in two canisters each placed in east and west directions. The heating of the fluids cause the panel to tilt over to the side with more sunshine. These will have viscous dampers to prevent excessive motion in response to wind gusts [2]. A chronological tracker uses a rotation mechanism to counteract the effect of Earth's rotation. A simple rotation mechanism, turning at a constant speed of one revolution per day or 15 degrees per hour, is adequate for many purposes, such as keeping a photovoltaic panel pointing within a few degrees of the Sun. This can easily be achieved by the use of a stepper motor control.

Figure 2: Principle of single axis solar tracking

The data for the insolation level and temperature for the whole year have been obtained from the NASA website for Aligarh and Doha [3]. The simulations have been run assuming that there is no condition of partial shading. For the purpose of simulation of energy output during the day, five solar panels of 250 Wp were taken in parallel to give a total of 1.25 kWp of power under STC. The energy outputs for the months throughout the year were obtained for two conditions: first for the fixed panel condition, and second for the panel with continuous one-axis solar tracking. The results have been compared and shown for Aligarh and Doha in Figs. 3 and 4 respectively. In Fig. 5, the percentage increase in the energy output for each month has been shown for both the cities.

Figure 3: Daily energy yield from a 1.25 kWp solar array on a monthly basis in Aligarh

Figure 4: Daily energy yield from a 1.25 kWp solar array on a monthly basis in Doha

Figure 5: Increase in daily energy yield on a monthly basis

References

[1] B H Khan ‘Non-Conventional Energy Resources’ Tata McGraw Hill, 2009.

[2] Kamala J. and Alex J., 2014, ‘Solar Tracking for Maximum and Economic Energy Harvesting’, Int. J. of Engg. and Tech, Vol. 5(6), pp 5030–5037.

[3] NASA Surface meteorology and Solar Energy website: https://eosweb.larc.nasa.gov

In this paper an open ended seven phase stator winding drive is considered for analysis that is to be fed from matrix converter controlled by space vector pulse width modulation scheme. Open-end winding variable speed drives with dual matrix converter supply have been extensively investigated for various applications in the past, based on a three-phase machine configuration. This topology is relatively simple for practical realization. It offers a higher number of switching states without the need for capacitor voltage balancing algorithms, when compared to the equivalent standard multi-level converter in single sided supply mode. This paper considers a seven-phase open-end winding topology. A relatively simple SVM algorithm, based on already developed seven-phase two level drive SVM method, is used for operation of both converters. The proposed modulation technique is straight forward to implement and is capable of generating pure sinusoidal output voltages, without any low-order harmonic components. The method offers superior harmonic performance when compared to seven-phase topology in single-sided supply mode. The developed scheme is verified by simulation, using a seven phase induction machine operated under V/f control. The proposed drive topology find application in high power ac drives such as in oil & gas industries, electric/hybrid electric vehicles, ship propulsion, traction etc. The simulation results support the proposed idea.

Abstract Objective: In this era of increasing antibiotic resistance (WHO)[1], we are running out of time as common bacterial infections are progressively rejecting drugs that would be standard for treatment. It is due to these reasons that research regarding bacteriophages, viruses that infect bacteria has seen a sudden revival. The Science Education Alliance- Phage Hunters Advancing Genomics and Evolutionary Science (SEA-PHAGES) headed by Dr. Graham Hatful from the Howard Hughes Medical Institute (HHMI)[2], University of Pittsburgh and Carnegie Mellon University has begun a nationwide initiative to discover, categorize and study the billions of bacteriophages that surround us. This initiative aims to create a thorough database containing genomic data for as many bacteriophages as possible. The study of these viruses is virtually new, and thus requires a significant effort; there is a novel, virtually untapped resource of genes and proteins that could greatly benefit our understanding of genomes and be used as treatments to bacterial infections that are resistant to antibiotics. Studying the bacteriophages is of great importance. The same protocols and procedures from the SEA-PHAGES program were applied to search for bacteriophages in Qatar within the sand and soil at Carnegie Mellon University Qatar. This is the first research of its kind to be carried out in Qatar and possibly at the Gulf region. Bacteriophages, which infect Arthrobacter.sp, were discovered in the sand from Al-Rayyan, Doha Qatar (Diversity of Bacteriophages in the ecology of Qatar). Following this, the viral plaques obtained were purified, isolated using a QIAamp MinElute Virus Kit[3] (Qiagen) and finally sequenced using Next Generation sequencing methods at Weil Cornell Medical University Qatar. Method: The sequenced DNA of phages were assembled using a Short Oligonucleotide Analysis Package- Denovo (SOAP-Denovo) software package. A program called Velvet has been also used in conjunction to ensure the best results were obtained using the optimal k-mer, providing the longest contig length. The longest length obtained was a contig of 12,380 at a k-mer of 59, along with a large number of smaller contigs. The largest 201 contigs have been annotated; gene nucleotide and protein sequences were collected, using the gene prediction software, GeneMarkS available online. Each of the genes from the contigs were then searched against the entire non redundant protein (NR) database of available annotated genes at the National Centre for Biotechnology Information (NCBI's) online database using Basic Local Alignment Search Tool (BLAST-p). They were also searched against non-submitted phage genomes collected at SEA-PHAGES. That result in about 558 annotated genes/proteins. All the proteins are being studied to understand better what the bacteriophage genome comprises of and how the proteins allow them to survive and infect bacteria in the sand collected from Al Rayyan in Doha. Results: So far three different bacteriophage contigs were found from the sequenced DNA, containing a total of 14 genes, most of which are derived from the Enterobacteriophage T7 cluster. However the individual genes displayed some variation from the original genes due to the small rate of mutations that naturally occurs with bacteriophages during replication. In addition to this, variations could be due to natural exchange of genetic information between viruses to form mosaic genomes. Thus each bacteriophage is unique due to this variation and each has proteins that can perform a slightly different function. One such gene was found had a 99% identity with Gene 3.5 from the Enterobacteriophage T7 family (phages that can infect Escherichia coli (E.coli) bacteria, which are commonly responsible for foodborne illnesses). This particular gene was searched against the PDB (protein database) from the same NCBI BLAST tool, to search for mutations. The query returned results of 100% identity with a (Chain L) T7 RNA Polymerase complexed with T7 lysozyme (interplay between an RNA polymerase and lysozyme). One particular bacteriophage contains a gene originating from a bacteriophage of the Yersinia species (phiA1122). This gene codes for a head-to-tail joining protein, which is a major component of a phage. This bacteriophage principally infects and neutralizes, Yersinia pestis, which is the causative agent of the Bubonic plague in humans[4] (Garcio.E). This particular gene must have been transferred during naturally occurring gene exchange between bacteriophages that infect the same organism simultaneously (Fleischmann, W) [5]. Discussion: The findings strongly suggest that Gene 3.5 has a function in breaking down the bacterial cell wall during infection. A further search on the Research Collaboratory for Structural Bioinformatics (RSCB) PDB was carried out to find a structural view of the protein. Upon studying the protein, it was found that the fragment containing the mutation is not seen in the crystal structure, which means it is a flexible loop. If this section of the protein moves in the crystal structure then it most probably moves in nature as well. This strongly suggests that the flexible mutated loop on the protein surface could affect of protein-protein interaction; and may result in slight changes in the mechanism (or temperature) by which the phage ligates or transfers genetic information from one phage to another. Future work: Future work aims to further study the Qatari bacteriophage genes and their proteins, their mutations and functions. Characterizing the remainder of the bacteriophage will allow us to better understand and annotate its genome. The relevance of these phages in a practical application could be in medical, industrial or agricultural uses. It could possibly have a role in treating E.coli infections or to prevent the contamination of such bacteria in the food industry. Further research could be done to sample more sand from various parts of Qatar (and various depths within the sand) to search for more bacteriophages. It is very likely that there are bacteriophages that could have more significant applications present within the sand. The same procedures could be followed to determine the functions and the nature of these phage genes.

References

[1] World Health Organization. 2015. Antimicrobial Resistance. Available at: http://www.who.int/mediacentre/factsheets/fs194/en/. Accessed on 13 November 2015.

[2] Howard Hughes Medical Institute. Science Education Alliance. Available at: http://www.hhmi.org/programs/science-education-alliance. Accessed on 13 November 2015.

[3] Qiagen.com. 2015. QIAamp MinElute Virus Kit. Available at: https://www.qiagen.com/us/shop/sample-technologies/combined-sample-technologies/preparation/qiaamp-minelute-virus-spin-kit/. Accessed on 13 November 2015.

[4] Garcio.E. 2003. The Genome Sequence of Yersinia pestis Bacteriophage φA1122 Reveals an Intimate History with the Coliphage T3 and T7 Genomes. Journal of Bacteriology. [Online]. Available at: http://jb.asm.org/content/185/17/5248.full. Accessed on 13 November 2015.

[5] Fleischmann. W.R. 1996. Chapter 43: Viral Genetics. Medical Microbiology 4th edition. Available at: http://www.ncbi.nlm.nih.gov/books/NBK8439/. Accessed on 13 November 2015.

Nanocrystalline metals -with grain sizes less than 100 nm- have proven to attain exceptional mechanical properties such as strengths that exceed those of coarse-grained and alloyed metals with grain size greater than 1 μm. As a result, such materials are to be acknowledged as the new class of high-performance engineering materials and to be implemented in various structural applications. The main reason behind the ultrahigh strength of this class of materials is mainly grain refinement, as in this mechanism, reducing grain size means introducing more grain boundaries. Grain boundaries act as barriers to the intra-grain dislocation motion, which is the main cause for the ductility of materials. Hence in its absence, the material is said to be strong and hard to deform. However, the strength associated with the new reduced grain size is associated with a penalty that leads to microstructural instabilities. This is because the atoms that lie in the grain boundary region are not as ordered and stabile as inside the grains. Hence those atoms are occupying unfavorable interfacial positions energetic wise, which means that they have high energy. As a result of the high volume fraction of grain boundaries, the system tends to pursue stabilization by seeking a configuration that shall allow for the lowest energy possible. The atomic system tends to eliminate the root of the problem which is the large number of grain boundaries and solve the problem by grain growth. Thus the removal of grain boundaries becomes the driving force to decreasing the system's energy. Hence an obstacle is yet to be overcome in order for those materials to be fully utilized to the maximum, as those nano-materials are prone to grain growth at lower temperatures than their conventional counterparts, which limits their service temperatures and expected lifetime. Grain growth can be slowed or even eliminated either thermodynamically, for example by adding solute atoms that segregate to the high energy sites in the grain boundaries, occupying it and lowering the free energy of the grain boundaries, or kinetically by the presence of second phase particles which results in grain boundary pinning, reducing the mobility of the grain boundaries and hence grain growth. This research aimed to studying the effect of adding 1% strontium (Sr) on stabilizing the grain boundaries of an aluminum-based alloy (Al-Mg-Li) which has a very low density yet a specific strength higher than that of steel. In order to achieve the goals of this research, a comparison must be made between the two samples of Al-5Mg-4Li and Al-5Mg-4Li-1Sr. Samples were prepared in a SPEX 8000 shaker mill and annealed at various temperatures up to 600 °C. To study the effect of Sr under various thermal conditions, both the as milled and annealed samples were analyzed using various experimental characterization methods such as X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) to perform a structural analysis and calculate the grain size of each sample. Using the Williamson-Hall model to calculate the average grain size for both samples based on the obtained XRD patterns, the results showed that for the as milled samples of Al-5Mg-4Li and Al-5Mg-4Li-1Sr, the average grain size was calculated to be 36.59 nm and 25.86 nm, respectively. The previous results were further proven when the TEM average grain size calculations gave similar results of 33 nm and 21 nm for the as-milled Al-5Mg-4Li and Al-5Mg-4Li-1Sr samples respectively. The thermal stability of the samples was proven when the grain size was measured after annealing at different temperatures for both Al-5Mg-4Li and Al-5Mg-4Li-1Sr samples. The average grain size was measured for Al-5Mg-4Li (annealed at 400 °C) and Al-5Mg-4Li-1Sr (annealed at 600 °C) to be 172.05 nm and 38.90 nm respectively. This shows that even at a higher temperature, the grain size for the sample that has Sr is much smaller and is still the nano-range. To verify the previous results of thermal stability, Vickers-hardness was measured for each sample after annealing as the mechanical properties of the thermally stabilized sample is expected to exceed those of the conventional sized sample. The plot of hardness variation of the nanocrystalline samples as a function of annealing temperatures showed that at room temperature, the hardness values for Al-5Mg-4Li and Al-5Mg-4Li-1Sr samples were 2.85 GPa and 3.24 GPa, respectively. With increasing annealing temperature, the hardness of Al-5Mg-4Li decreases gradually and reaches a low value of 0.8 GPa after annealing at 600 °C. In contrast, Al-5Mg-4Li-1Sr showed excellent thermal stabilization with increasing annealing temperature. Increasing the annealing temperature to 600 °C decreased the hardness value to 2.73 GPa. This hardness value is almost as high as the hardness of the as milled Al-5Mg-4Li (2.85 GPa) at room temperature. Since the XRD patterns did not show any traces of second phase particles, we suggest that the stabilization of the grain size and hence other mechanical properties such as hardness at high temperatures can be attributed to solute drag or the thermodynamic mechanism. Grain Growth does not only limit the nano-crystalline materials service temperatures, but also its unique technological applications as a consequence. Hence we anticipate that the results of this research will have implications in the development of thermally stabilized ultra-tough nanostructured materials for technological applications.

Thermoelectric (TE) is the science associated with converting the thermal energy into electricity based on the Seebeck effect. The attractive features of thermoelectric devices are their long life, low maintenance, highly reliable and they do not produce emissions harmful to the environment. Thermoelectric generators are used to provide electrical power in medical, military, and space applications where their desirable properties outweigh their relatively high cost and low operating efficiency. However, the widespread use of thermoelectric components is presently limited by the low figure-of-merit of presently known materials. Bismuth telluride Bi2Te3 (which has a peak ZT value of 1.1) is currently regarded as the state-of-the art TE material with high efficiency and is therefore attractive for energy harvesting processes. The objective of the work is to demonstrate a new route to the realization of highly efficient bulk Bi2Te3 structures at the nanoscale. Nanostructures provide a chance to disconnect the linkage between thermal and electrical transport by introducing some new scattering mechanisms. This will help in increasing figure of merit and then the efficiency. We present in this work novel versions of both p-type and n-type Bi2Te3 alloy materials with significantly enhanced figures of merit (ZT) between 25 °C and 125 °C.

There is considerable investment in construction industry in Qatar for civil infrastructures and taking into account the severe environmental conditions, they would entail for proper maintenance, repair and strengthening for safe, continuous, uninterrupted, and efficient functionality. Reinforced concrete (RC) structural members, which constitute majority of construction works in Qatar, can be easily deteriorated by the deleterious effect of seawater exposure in the form of humidity or direct splashing for sea-level and offshore structures. Such deterioration can also be due to the exposure to extreme high temperatures, severe humidity and high chloride. All such environmental effect can significantly reduce the life-span of RC structures by up to 10-15 years.

The cost of rehabilitation and strengthening is usually estimated in millions of dollars. Traditional methods of strengthening corrosion-damaged structures involve the replacement of the corroded bars and the substitution of deteriorated concrete layers with new concrete. Our study proposes an “optimum strengthening technique” for RC structures to mitigate the prevailing conditions of Qatar. This relatively new technique utilizes “textile-reinforced mortar (TRM)” to strengthen concrete beams. TRM systems consist of one or more layers of textiles made of carbon, glass, or Polyparaphenylene benzobisoxazole (PBO) grids that are sandwiched between layers of associated cementitious mortars. The cement-based mortar used in TRM acts as a barrier against chloride ions penetration thus protecting the main reinforcing bars from corrosion attack. Textiles' lightweight, high tensile strength, corrosion resistance, and ease of application make the strengthening system appealing. The potential of TRM for the repair and strengthening of concrete structures is not just the result of its physio-mechanical performance but also the ease and simplicity of installation that does not require any sophisticated equipment or retraining of the construction work. In addition, the compatibility between the mortar used and the concrete substrate is inherited since both materials have the cement as a common “base”. TRM systems, with their innovative features, ensure the endurance of the rehabilitation process and consequently the sustainability of the strengthened structure.

Recently in the last few years, several research works in the USA and Europe in the field of TRM strengthening technique have been reported for masonry and concrete structural members. Majority of these works is limited to single type of textile (either carbon, PBO or glass) and on limited types of reinforcement levels. The work presented here compares two different types of TRM systems in the same domain, performed on three different levels of reinforcement ratios representing flexural deficient, lightly reinforced and typical under-reinforced beams.

Experimental works were done to state the efficiency and effectiveness of textile reinforced mortar (TRM) in increasing the ductility and the flexural capacity of reinforced concrete (RC) beams. The aim of the experimental work was to investigate the parameters that contribute to the increase in the load carrying capacity of beams strengthened with TRM system. Eighteen medium-scale rectangular RC beam specimens, 2500 mm long, 150 mm wide and 260 mm deep, were prepared at three different reinforcement ratios of “ “ρ” _“s” ^“1” “ = 0.5%;” o “ρ” _“s” ^“2” “ =  0.72%;” f: “ρ” _“s” ^“1” “ = 0.5%; “ “ρ” _“s” ^“2” “ =  0.72%; “ “ρ” _“s” ^“3” “ = 1.27%.” The strengthened beams utilized two TRM types namely carbon and Polyparaphenylene benzobisoxazole (PBO) TRM systems respectively. The RC beam specimens were tested in flexure under four point loading until failure with a clear span of 2.2 m. The strengthening technique was applied to the soffit of the beam (flat type) altering the number of layers of textile. Three beams (of three different reinforcement ratios) without TRM strengthening were used as control specimens. Nine beams were externally reinforced by one (“ρ” _“T-c” ^“1” “ =  0.014%”), two (“ρ” _“T-c” ^“2” “ =  0.028%”) and three (“ρ” _“T-c” ^“3” “ =  0.041%”) layers of carbon TRM system. Six beams were strengthened with one (“ρ” _“T-PBO” ^“1” “ =  0.009%”) and two (“ρ” _“T-PBO” ^“2” “ =  0.018%”) layers of PBO TRM system.

From Based on the experimental observations, a reasonable gain in flexural strength and energy absorption was achieved for both the TRM systems. An increase of the initial stiffness was achieved for strengthened specimens; however, an apparent decrease in the overall ductility was observed with TRM strengthening. Results showed that the flexural capacity of strengthened beams increased to an average of 38% for carbon TRM system and an average of 26.7% for PBO TRM system over that of their control (un-strengthened) specimens. The highest increase in the load carrying capacity was 77.51% for a specimen having with the main reinforcement ratio of D12 (“ρ” _“s” ^“2” “ =  0.72%)” and was strengthened with carbon TRM system using three layers of carbon textile.

Ductility index (ΔI) and energy absorption (Ψ) values were also calculated in order to know the behavior of ductility and flexural capacity in each of the beam specimen. The term ductility index (ΔI) is defined as the ratio between the deflection at the ultimate load and that at yield load, representing its ability to stretch/deform under sustained load before fracture. During experimentation, it was observed that the average values of ductility indices of using carbon as strengthening material were 1.1 × , 1.2 ×  and 0.5 ×  for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ =  0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” beam specimens respectively to that of their control specimen. Similarly the average values of ductility indices of using PBO as strengthening material were 2.42 × , 0.75 ×  and 0.56 ×  for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ =  0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” specimens respectively to that of the control specimen. Also the term energy absorption (Ψ) is defined as the area under the load- deflection curve up to the ultimate load, representing the amount of energy absorbed by the specimen before complete failure. The average values of energy absorption for using carbon as strengthening material were 1.8 × , 1.2 ×  and 1.6 ×  for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ =  0.72% and “ “ρ” _“s” ^“3” “ = 1.27%” beam specimens respectively to that of the control specimen. Similarly the average values of energy absorption for using PBO as strengthening material were 2.0 × , 1.0 ×  and 1.5 ×  for “ρ” _“s” ^“1” “ = 0.5%,” “ρ” _“s” ^“2” “ =  0.72% and” “ρ” _“s” ^“3” “ = 1.27%” specimens respectively to that of the control specimen.

Therefore, both the adopted TRM systems performed exceptionally well within the scope of the work, with carbon TRM system showing a relatively higher increase in the capacity of strengthened specimens and PBO TRM systems exhibiting relatively more ductile failure with higher bond strength between the TRM surface and concrete substrate. Moreover, crack patterns for the strengthened beam showed effective distribution of cracks/damage over the length of beam as compared to severe and concentrated damage in the associated control un-strengthened beams. Further, during the experimentation, it was seen that the technique of applying the TRM system also considers the contractor's ease where the construction workers (although not very skilled) can easily implement the technique after being given simple demonstrations.

The study puts forth proper procedures and standards to the construction industry on the rehabilitation and strengthening of the existing concrete structures using innovative TRM strengthening technique. Successful implementation of the project will result in “state-of-the-art recommendations for design and construction specifications”, which will place Qatar and research at Qatar University in a leadership position not only limited to the Gulf region. Furthermore, this can potentially act as an “important initiation for the development of new industrial opportunities” in the country.

Keywords

Reinforced concrete beams, textile reinforced mortar, flexural strengthening, ductility index, energy absorption.

Introduction: Pathogen attacks impose natural selection on plants to evolve complex arrays of defensive strategies. Among the diverse defensive mechanisms evolved by plants to withstand pathogen attack, the ability to synthesize an arsenal of low-molecular weight volatile and non-volatile chemicals including phenolics helps them to prepare a robust defense response against pathogen entry. Systemic induction and accumulation of low molecular weight phenolics is observed in response to various diseases and thus are studied as markers for resistance to pathogens. Phenolics that exhibit anti-oxidant activity exert their inhibitory effects on pathogen colonization via protein precipitation and iron depletion.

Phytochemical analysis have been proved that date palm is rich source of phenol. Very little information is available on the inherent Date palm phenolic content that has been involved as resistance factors. All the studies are focused on phenolic content from date palm fruit and its property. Here we focusing on comparative analysis of phenolics from different cultivars leaf and how it affect the different pathogenic fungi. Material and Methods: We conducted a genome mining analysis of date palm whole genome available in the NCBI site, to detect the presents of enzyme involved in the secondary metabolite pathway. Analyzed the presents of receptor protein specific for the recognition of fungal pathogen.

Five date palm pathogens were isolated from the diseased date palm and surrounding soil from the date palm field located in northern region of Qatar. Leaf, shoot and root samples collected from the diseased date palm and rhizosphere soil collected from near the diseased date palm. Samples were stored at 40?C in aseptic condition until further use. Sterilized plant samples were plated in the potato dextrose agar (PDA) for the fungal isolation and the soil were plated on molten agar for fungal isolation. The plates were incubated at 250?C until single colony appeared. The isolated fungi were examined under microscope. Based on the microscopic and physical characteristics fungi were identified.

The pathogenicity were determined with detached leaf inoculation analysis and in vivo pathogenicity analysis with three date palm cultivar varieties. Detached leaf inoculation analysis performed in laboratory condition and the in vivo pathogenicity conducted in green house with controlled growth condition. The date palm varieties used in this current study are Khalas, Khneezi and Barhi. All the four pathogens, Fusarium solani, Fusarium oxysporum, Rhizectonia solani Fusarium sp and Ceratocystis radicicola were used for pathogenicity analysis.

Total phenolic were extracted from three date palm culvars through water extraction procedure. Extraction performed with different temperature range. Comparative analysis of antifungal property of total phenolics from different date palm cultivars such as Khalas, Khneezi and Barhi was carried out after optimizing extraction temperature. Antifungal activity is determined with disc diffusion analysis. 100 μl of extract impregnated filter disc (10 mm in diameter) placed on the PDA plate followed by fungal disc placed on the disc. Plates were incubated at 250?C and the fungal growth monitored. Experiment repeated in triplicate along with control. Results and conclusion: The genome mining analysis of date palm result revealed 45 enzyme sequences from shikimate pathway, which is a support for the active synthesis of phenolic content in date palm. Plant phenolics synthesize via shikimate-phenylpropanoid-flavonoid pathways and include phenolic acids, flavanoids, tannins and less common stilbenes and lignins. Presents of chitin elicitor receptor kinase in date palm indicate the phytopathogenic fungal detection ability of date palm.

From the isolated fungi, the date palm pathogenic fungi were screened and subcultured. Five pathogenic fungi were isolated, Fusarium solani, Fusarium oxysporum, Rhizectonia solani, Fusarium sp and Ceratocystis radicicola. Pathogenicity of all the five isolated fungi were confirmed by analyzing necrosis caused on the date palm leaf (Fig. 1). The frequency of necrotic lesion and disease susceptibility found more in Khneezi than Khalas and Barhi.

Water extraction procedure conducted at 400?C for 24 hrs were accepted as standardized phenolic extract for antifungal activity. Growths of the fungi were measured after 3 day and 5 days of incubation to determine the antifungal activity of phenolic extract (table 1). Phenolic extract from the Khalas showed more antagonistic activity against Rhizectonia solani whereas phenolic extract from Barhi showed more inhibitory activity against Fusarium solani, Fusarium oxysporum and Ceratocystis radicicola. In all the experiment Khneezi showed week inhibitory activity this supports our previous susceptibility study (not published) in that Khneezi showed more susceptible to C.radicicola. This result is an evident for the disease resistant activity of date palm phenolics.

Automotive researchers attempts to simulate combustion of fuels in order to improve engine performance.[1] Conventional fuels are difficult to represent in these simulations due to their complex composition. Surrogates that meet American Society of Testing and Materials (ASTM) standards are a good alternative to conventional fuels. This study aims at design and analyzing surrogate mixtures for both gasoline and diesel. Surrogates were designed through a computer aided model developed at the Technical University of Denmark.[2] The model architecture has four structures viz., (i) problem definition (ii) property model identification (iii) mixture blend design and (iv) model-based verification.

Surrogate diesel, comprised of five paraffinic compounds viz., n-dodecane, n-tetradecane, tetralin, cyclo-octaneand iso-cetane in different volumetric ratios. Surrogate gasoline comprised of six different chemicals viz. n-butane, n-heptane, iso-octane, 1-pentene, methyl cyclopentane and toluene in different volumetric ratios. Target physical properties of these fuel surrogates were measured using advanced analytical equipment and experimental techniques developed at Texas A&M University at Qatar.[3] Diesel surrogate was tested for the target properties employed in the model viz. density, viscosity, heat content, flash point, vapor pressure, pour point, cloud point and distillation curve. Butane present in the gasoline surrogate hampers handling and testing since it is extremely critical to prepare a homogeneous blend that comprises of both liquids and a permanent gas. Also, the conventional sampling technique was found to be ineffective to prevent loss of permanent gas in the surrogate. Therefore, a novel sampling methodology and advanced blending technique was developed to minimize loss of butane and volatile components such as 1-pentene. Detailed Hydrocarbon Analysis (DHA) for gasoline surrogate was carried out by Gas Chromatography (GC) according to ASTM D6730 to verify the efficacy of blending technique as well as sampling method. The composition analysis through DHA confirmed that the blending and sampling methodology was accurate with maximum relative standard deviation of approx. 5.82%. Subsequently gasoline surrogate was tested for density, viscosity, vapor pressure, heat content, distillation curve and compositional attributes.

The surrogate mixtures prepared in this study complied well with their respective ASTM standards for the properties measured. The work would further be continued to investigate the engine performance and emission characteristics for diesel surrogate. Engine performance will be evaluated in terms of Power/Torque and Theoretical Brake Specific Fuel Consumption (BSFC). Emissions of Carbon Monoxide (CO), Hydrocarbon (HC) and Nitrogen Oxides (NOx) will be determined. Results of this study provide a basis to further improving the computer aided models used to design the surrogates and for design of future generations of efficient fuels of different composition obtained from both conventional sources (petroleum) and non-conventional sources (e.g. from natural gas via gas-to-liquid (GTL), coal via coal-to-liquid (CTL) or biofuels). Also, the outcome of this study will be used to optimizing the design of fuel blends obtained from the aforementioned sources.

References

[1] Pitz, W. J., & Mueller, C. J. (2011). Recent progress in the development of diesel surrogate fuels. Progress in Energy and Combustion Science, 37(3), 330–350.

[2] Yunus, N. A., Gernaey, K. V., Woodley, J. M., & Gani, R. (2014). A systematic methodology for design of tailor-made blended products. Computer and Chemical Engineering, 66, 201–213.

[3] Elmalik, E.E., Raza, B., Warrag, S., Ramadhan, H., Alborzi, E., Elbashir, N.O. (2014). Role of Hydrocarbon Building Blocks on Gas-to-Liquid Derived Synthetic Jet Fuel Characteristics. Industrial & Engineering Chemistry Research, 53, 1856–1865.

Hybrid Perovskites (HP) recently emerged as alternative light harvesting layer to fabricate high efficiency thin film solar cells. The perovskite based solar cells took advantage of the experience gained in the field of the dye sensitizes solar cells and the extremely thin absorber (ETA) solar cells. It is worth mentioning that the structure of the perovskite solar cell is very similar to a dye sensitized solar cell and ETA solar cell. These cells are composed of the transparent conducting layer (TCO), the electron transport material (ETM) the absorber, the hole transport material, and the back contact. Our work focuses on the deposition and characterization of two components of the perovskite based solar cell. These components are the ETM which is titanium dioxide layer (TiO2) in this case and the absorber material which is the perovskite layer. Dip coating technique was used to grow compact and pinhole free TiO2 films from a solution of Titanium alkoxide diluted in isopropanol. The dip coating technique is particularly attractive for thin film solar cell application due to its simplicity, low cost, and good quality of films. For a compact film, dipping was restricted to two dips and four dips. The films were structurally and morphologically characterized by X-ray diffraction and scanning electron microscope (SEM). XRD analysis showed the deposited TiO2 films have anatase structure. SEM results showed a full coverage of the films with less pinholes. The two step sequential physical vapour deposition was performed to grow HP thin films using thermal evaporation technique. Thin films of HP were deposited using thermal evaporator under high vacuum from two sources namely lead iodide and methylamine iodide. Firstly, Lead iodide was deposited which acts as a template for the crystallization of perovskite layers. Then methylamine iodide was deposited for the desired film. X-ray diffraction of the as deposited film showed the presence of mixed phases of lead iodide and perovskites. This indicates at room temperature methylamine iodide diffused deep enough in the lead iodide film to form the perovskite structure. Films were then annealed at 110 °C for 1 hour in nitrogen atmosphere for better crystallinity which is proven by the sharper and high pick intensities. Also, varying the ratio of both organic and inorganic sources did not influence the presence of lead iodide phases as confirmed by XRD. Further optimization are in progress to form single perovskite phase formation.