Search results for: Abbas Ali Mahdi

Authors: Ali Raheli, Rahim Habibifar, Behzad Mohammadi-Alasti, Mahdi Abbasgholipour

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This paper presents vibration behavior of a FGM micro-beam and its pull-in instability under a nonlinear electrostatic pressure. An exponential function has been applied to show the continuous gradation of the properties along thickness. Nonlinear integro-differential-electro-mechanical equation based on Euler–Bernoulli beam theory has been derived. The governing equation in the static analysis has been solved using Step-by-Step Linearization Method and Finite Difference Method. Fixed points or equilibrium positions and singular points have been shown in the state control space. In order to find the response to a step DC voltage, the nonlinear equation of motion has been solved using Galerkin-based reduced-order model and time histories and phase portrait for different applied voltages have been shown. The effects of electrostatic pressure on stability of FGM micro-beams having various amounts of the ceramic constituent have been investigated.

Keywords: FGM, MEMS, nonlinear vibration, electrical, dynamic pull-in voltage

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Authors: Abbas Vahedian, Rijun Shrestha, Keith Crews

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The bond mechanism between timber and fibre reinforced polymer (FRP) is relatively complex and is influenced by a number of variables including bond thickness, bond width, bond length, material properties, and geometries. This study investigates the influence of bond thickness on the behaviour of interface, failure mode, and bond strength of externally bonded FRP-to-timber interface. In the present study, 106 single shear joint specimens have been investigated. Experiment results showed that higher layers of FRP increase the ultimate load carrying capacity of interface; conversely, such increase led to decrease the slip of interface. Moreover, samples with more layers of FRPs may fail in a brittle manner without noticeable warning that collapse is imminent.

Keywords: fibre reinforced polymer, FRP, single shear test, bond thickness, bond strength

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Authors: Hamzeh Soltanali, Abbas Rohani, A. H. S. Garmabaki, Mohammad Hossein Abbaspour-Fard, Adithya Thaduri

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Toward continuous innovation and high complexity of technological systems, the automotive manufacturing industry is also under pressure to implement adequate management strategies regarding availability and productivity. In this context, evaluation of system’s performance by considering reliability, availability and maintainability (RAM) methodologies can constitute for resilient operation, identifying the bottlenecks of manufacturing process and optimization of maintenance actions. In this paper, RAM parameters are evaluated for improving the operational performance of the fluid filling process. To evaluate the RAM factors through the behavior of states defined for such process, a systematic decision framework was developed. The results of RAM analysis revealed that that the improving reliability and maintainability of main bottlenecks for each filling workstation need to be considered as a priority. The results could be useful to improve operational performance and sustainability of production process.

Keywords: automotive, performance, reliability, RAM, fluid filling process

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Authors: Tarek S. Jamil, H. A. Abbas, Rabab A. Nasr, Eman S. Mansor, Rose-Noëlle Vannier

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The citrate manner (Pechini method) was utilized in elaboration of a novel Nano-sized BaFe(1-x)CuxO3 (x=0.01, 0.05 and 0.10). The prepared photocatalysts were characterized by x-ray diffraction, diffuse reflectance, TEM and the surface area. The prepared samples have a mixture of cubic perovskite structure (main) and orthorhombic phases. The effect of different loads of copper as dopant on the structural properties as well as the photocatalytic activity was demonstrated. The lattice parameter and the unit cell volume of the prepared materials are given. Doping with copper increased the photocatalytic activity of BaFeO3 several times in abstraction of hazardous atrazine that causes acute problems in drinking water treatment facilities. This may be reasoned to low band gap energy of copper doped BaFe(1-x)CuxO3 attributed to oxygen vacancies formation.

Keywords: photocatalysis, nano-sized, BaFeO3, copper doping, atrazine

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Authors: Abbas R. Ali, Safa H. Abdulrahman

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In this study, forty samples had been collected from water of Lesser Zab River and drinking water to determine fluoride concentration and show the impact of fluoride on general health of society of Kirkuk city. Estimation of fluoride concentration and determination of its proportion in water samples were performed attentively using a fluoride ion selective electrode. The fluoride concentrations in the Lesser Zab River samples were between 0.0265 ppm and 0.0863 ppm with an average of 0.0451 ppm, whereas the average fluoride concentration in drinking water samples was 0.102 ppm and ranged from 0.010 to 0.289 ppm. A comparison between results obtained with World Health Organization (WHO) show a low concentration of fluoride in the samples of the study. Thus, for health concerns we should increase the concentration of this ion in water of Kirkuk city at least to about (1.0 ppm) and this will take place after fluorination process.

Keywords: fluoride concentration, lesser zab river, drinking water, health society, Kirkuk city

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Authors: Hassan Mahdi

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The integration of computer-assisted translation (CAT) tools in translation creates several opportunities for translators. However, this integration is not useful in all types of English structures. This study aims at examining the impact of using CAT tools in translating collocations. Seventy students of English as a foreign language participated in this study. The participants were divided into three groups (i.e., CAT tools group, Machine Translation group, and the control group). The comparison of the results obtained from the translation output of the three groups demonstrated the improvement of translation using CAT tools. The results indicated that the participants who used CAT tools outscored the participants who used MT, and in turn, both groups outscored the control group who did not use any type of technology in translation. In addition, there was a significant difference in the use of CAT for translation different types of collocations. The results also indicated that CAT tools were more effective in translation fixed and medium-strength collocations than weak collocations. Finally, the results showed that CAT tools were effective in translation collocations in both types of languages (i.e. target language or source language). The study suggests some guidelines for translators to use CAT tools.

Keywords: machine translation, computer-assisted translation, collocations, technology

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Authors: Saeb Ahmadi, Mohsen Vafaie Sefti, Mohammad Mahdi Shadman, Ebrahim Tangestani

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Carbon nanotube has shown great potential for the removal of various inorganic and organic components due to properties such as large surface area and high adsorption capacity. Central composite design is widely used method for determining optimal conditions. Also due to the economic reasons and wide application, the rare earth elements are important components. The analyses of cerium (Ce(III)) adsorption as one of the Rare Earth Elements (REEs) adsorption on Multiwall Carbon Nanotubes (MWCNTs) have been studied. The optimization process was performed using Response Surface Methodology (RSM). The optimum amount conditions were pH of 4.5, initial Ce (III) concentration of 90 mg/l and MWCNTs dosage of 80 mg. Under this condition, the optimum adsorption percentage of Ce (III) was obtained about 96%. Next, at the obtained optimum conditions the kinetic and isotherm studied and result showed the pseudo-second order and Langmuir isotherm are more fitted with experimental data than other models.

Keywords: cerium, rare earth element, MWCNTs, adsorption, optimization

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Authors: Mahdi Mottahedi, Peter Zahn, Armin Lechler, Alexander Verl

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Optimal topology of components leads to the maximum stiffness with the minimum material use. For the generation of these topologies, normally algorithms are employed, which tackle manufacturing limitations, at the cost of the optimal result. The global optimum result with penalty factor one, however, cannot be fabricated with conventional methods. In this article, an additive manufacturing method is introduced, in order to enable the production of global topology optimization results. For a benchmark, topology optimization with higher and lower penalty factors are performed. Different algorithms are employed in order to interpret the results of topology optimization with lower factors in many microstructure layers. These layers are then joined to form the final geometry. The algorithms’ benefits are then compared experimentally and numerically for the best interpretation. The findings demonstrate that by implementation of the selected algorithm, the stiffness of the components produced with this method is higher than what could have been produced by conventional techniques.

Keywords: topology optimization, additive manufacturing, 3D-printer, laminated object manufacturing

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Authors: Dandi Bachtiar, Mohammed Ausama Abbas, Januar Parlaungan Siregar, Mohd Ruzaimi Bin Mat Rejab

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Short sugar palm fibre and thermoplastic polyurethane were combined to produce new composites by using the extrude method. Two techniques used to prepare a new composite material, firstly, extrusion of the base material with short fibre, secondly hot pressing them. The size of sugar palm fibre was fixed at 250µm. Different weight percent (10 wt%, 20 wt% and 30 wt%) were used in order to optimise preparation process. The optimization of process depended on the characterization mechanical properties such as impact, tensile, and flexural of the new (TPU/SPF) composite material. The results proved that best tensile and impact properties of weight additive fibre applied 10 wt%. There was an increasing trend recorded of flexural properties during increased the fibre loading. Meanwhile, the maximum tensile strength was 14.0 MPa at 10 wt% of the fibre. Moreover, there was no significant effect for additions more than 30 wt% of the fibre.

Keywords: composites, natural fibre, polyurethane, sugar palm

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Authors: Muhammad Taimoor Hassan, Kausar Abbas

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The Islamic Banking Services is one of the growing businesses in financial sector around the globe with 15 to 18 percent growth all over the world and 10-12 percent growth rate in Pakistan. This research study is aimed at measuring the impact of religiosity on the customer loyalty of Islamic Banking in Pakistan. The study has utilized cause and effect research design to assess the impact of religiosity on Islamic Banking. Data from 350 respondents have been collected to meet the purpose of the study. The results revealed that the religiosity has a significant impact on the customer loyalty of Islamic Banking through the customer attitude and customer trust on the sequential model. The results suggest that the religiosity, customer attitude, and customer trust are the interconnected variables which lead to customer loyalty in Islamic Banking of Pakistan. The study is useful in the setting of Pakistan to further increase the customer loyalty for Islamic Banks.

Keywords: Islamic banks, customer loyalty, attitude, Pakistan

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Authors: M. Nuhu, M. S. Amina, A. H. Aminu, A. J. Abbas, N. Salahudeen, A. Z. Yusuf

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Transesterification of jatropha methyl ester (JME) with the common polyol, trimethylolpropane (TMP) produced the TMP based ester which exhibits improved temperature properties. This paper discusses the physic-chemical properties of jatropha bio-lubricant base oil applicable for ISO VG32 and VG46 requirement. The catalyst employed for the JME was CaO synthesized in National Research Institute for Chemical Technology (NARICT) that gives 100% conversion. The molar ratio of JME to TMP was 3.5:1 and the catalyst (NaOCH3) loading were found to be 0.8% of the weight of the total reactants. The final fractionated jatropha bio-lubricant base was found to contain 11.95% monoesters, 43.89% diesters and 44.16% triesters (desired product). In addition, it was found that the bio-lubricant base oil produced is comparable to the ISO VG46 commercial standards for light and industrial gears applications and other plant based bio-lubricant.

Keywords: biodegradability, methyl ester, pour point, transesterification, viscosity index

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Authors: Abbas Fazelinia

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Terrorism is not a new phenomenon to the world, yet it remains difficult to define and to counter. Countering terrorism requires several measures that must be taken at the same time. Counterterrorism strategies of most countries depend on military measures. However, those strategies should also focus on nonlethal measures, such as economic, political, and social measures. The psychological dimensions of terrorism must be understood, evaluated, and used in countering terrorism. This study suggests that psychological operations, as nonlethal military operations, can be used to influence individuals not to join terrorist organizations and to facilitate defections from terrorist organizations. However, in order to implement effective psychological operations, one has to have appropriate intelligence about terrorist organizations. Examining terrorist organizations help us to identify their vulnerabilities and obtain this intelligence. This article concludes that terrorists’ motivations, terrorist organizations’ radicalization, recruitment, and conversion processes, ideology, goals, strategies, and general structure form the intelligence requirement for psychological operations in counterterrorism. The methodology used in this article is a mixed method.

Keywords: psychological operations, terrorist, counterterrorism, terrorism

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Authors: Mohammad Mahdi Kioumarsi

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In this paper, using the response surface method (RSM), tornado diagram method and non-linear finite element analysis, the effect of four parameters on residual bending capacity of a corroded RC beam was investigated. The parameters considered are amount of localised cross section reduction, ratio of pit distance on adjacent bars to rebar distance, concrete compressive strength, and rebar tensile strength. The focus is on the influence on the bending ultimate limit state. Based on the obtained results, the effects of the ratio of pit distance to rebar distance (Lp⁄Lr) and the ratio of the localised cross section reduction to the original area of the rebar (Apit⁄A0) were found significant. The interference of localised corrosion on adjacent reinforcement bars reduces the bending capacity of under-reinforced concrete beam. Using the sensitivity analysis could lead to recognize uncertainty parameters, which have the most influences on the performance of the structure.

Keywords: localised corrosion, concrete beam, sensitivity analyses, ultimate capacity

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Authors: Adistya Maulidya, Mujuna Abbas, Nur Assyifa, Putri Dewi Gutiyani

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Countries are moving forward to develop databases from electronic health records for monitoring and research. Since the issuance of Information and Electonic Transaction Constitution No. 11 of 2008 as well as Minister Regulation No. 269 of 2008, there has been a gradual progress of Indonesian hospitals adopting Electonic Health Record (EHR) in its systems. This paper is the result of a literature study about the progress that has been made in Indonesia to develop national health information infrastructure through EHR within the hospitals. The purpose of this study was to describe trends in adoption of EHR systems among hospitals in Indonesia from 2008 to 2015 as well as to assess the preparedness of Indonesian national health information infrastructure facing ASEAN Economic Community.

Keywords: adoption, Indonesian hospitals, electronic health record, ASEAN economic community

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Authors: H. Aburideh, Z.Tigrine, D. Ziou, S. Hout, R. Bellatreche, D. Belhout, Z. Belgroun, M. Abbas

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Faced with climate hazards in recent decades and the constant increase of the population, Algeria is making considerable efforts to provide water resources and water availability, both for its nascent industry, agriculture and for the drinking water supply of cities and arid region of the country. Following a remarkable worldwide technological breakthrough in seawater and brackish water desalination, known in recent years, the specialists have seen that the use of desalination of sea water in Algeria is a promising alternative as long as it has a coastline of 1200 km. Seawater is clean and virtually inexhaustible resource; mainly for population and industry that have high water consumption and are close to the sea. The purpose of this work is to present information on the number of sea water desalination stations and demineralization plants existing in Algeria. The constraints related to the operation of certain stations; those which are operational, those that are not operational as well as the seawater desalination program that was hired to cover 49 desalination plants across the country at the end of 2019 with the aim of increasing and diversifying water resources.

Keywords: desalination, water, membrane, demineralization

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Authors: Aref Zribi, Sonia Ben Nasr, Sana Fendri, Mahdi Balti, Abderazzek Haddaoui

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Background: Despite their benefit, Endocrine therapies (ET) are known to have substantial adverse events (AEs) such as hot flashes, mood disorders and osteoarticular pain. ET induced alopecia(EIA) is less frequently noted by patients and is less reported in the literature. The aim of our study was to report ET alopecia characteristics and their influence on patient and treatment observance. Method: We conducted a retrospective study including luminal BC patients treated in the oncology department of the military hospital of Tunis between January 2015 and December 2020. Patients treated with previous chemotherapy-inducing alopecia were excluded. Results: 145 female patients were included. The median age was 59 years. EIA was reported in 44% of cases. Alopecia was attributed to aromatase inhibitors in 53% and tamoxifen in 21%. Severity was grade 1 in 80% and grade 2 in the remaining cases. ET discontinuation because of alopecia was noted in 6.5 % of patients. Moderate improvement of alopecia was observed with topical minoxidil and Thallium metallicum 9CH homeopathy during ET in 60% of patients. Conclusions: EIA is frequent in BC patients and should be considered to improve treatment observance and patients’ quality of life.

Keywords: endocrine therapy, alopecia, breast cancer, Tunisia

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Authors: Rima Zakzouk, Noriko Hiraishi, Mohamed Mahdi Alshahni, Koichi Makimura, Junji Tagami

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Background and Purpose: Silver diamine fluoride (SDF) is used to prevent and arrest dental caries. The aim of this study is to evaluate the effect of SDF on reducing Candida albicans adhesion on dentin. Materials and Methods: Bovine dentin disks (6×6 mm) were cut by Isomet and polished using grit silicon carbide papers down to 2000 in order to obtain flat dentin surfaces. Samples were divided into two groups. The first group (SDF group) was treated with 38% SDF for 3 min, while the other group (control group) did not undergo SDF treatment. All samples were exposed to C. albicans suspension, washed after 6 hours incubation at 30 °C before to be tested using XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) and real time PCR approaches. Statistical analyses of the results were performed at the significance level α = 0.05. Results: SDF inhibited C. albicans adhesion onto dentin. A significant difference was found between the SDF and control groups in both XTT and real time PCR tests. Conclusion: Using SDF to arrest the caries, could inhibit the Candida growth on dentin.

Keywords: silver diamine fluoride, dentin, real time PCR, XTT

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Authors: Mahdi Fakoor, Seyed Mohammad Navid Ghoreishi

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Composite patching is a common way for reinforcing the cracked pipes and cylinders. The effects of composite patch reinforcement on fracture parameters of a cracked pipe depend on a variety of parameters such as number of layers, angle, thickness, and material of each layer. Therefore, stacking sequence optimization of composite patch becomes crucial for the applications of cracked pipes. In this study, in order to obtain the optimal stacking sequence for a composite patch that has minimum weight and maximum resistance in propagation of cracks, a coupled Multi-Objective Genetic Algorithm (MOGA) and Finite Element Method (FEM) process is proposed. This optimization process has done for longitudinal and transverse semi-elliptical cracks and optimal stacking sequences and Pareto’s front for each kind of cracks are presented. The proposed algorithm is validated against collected results from the existing literature.

Keywords: multi objective optimization, pareto front, composite patch, cracked pipe

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Authors: Mohammad Mahdi Paydar, Armin Cheraghalipour, Mostafa Hajiaghaei-Keshteli

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Nowadays, in advanced countries, agriculture as one of the most significant sectors of the economy, plays an important role in its political and economic independence. Due to farmers' lack of information about products' demand and lack of proper planning for harvest time, annually the considerable amount of products is corrupted. Besides, in this paper, we attempt to improve these unfavorable conditions via designing an effective supply chain network that tries to minimize total costs of agricultural products along with minimizing shortage in demand points. To validate the proposed model, a stochastic optimization approach by using a branch and bound solver of the LINGO software is utilized. Furthermore, to accumulate the data of parameters, a case study in Mazandaran province placed in the north of Iran has been applied. Finally, using ɛ-constraint approach, a Pareto front is obtained and one of its Pareto solutions as best solution is selected. Then, related results of this solution are explained. Finally, conclusions and suggestions for the future research are presented.

Keywords: perishable products, stochastic optimization, agricultural supply chain, ɛ-constraint

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Authors: Ehsan Saghehei, Mahdi Eghbali

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The maximal covering location problem (MCLP) was originally developed to determine a set of facility locations which would maximize the total customers' demand serviced by the facilities within a predetermined critical service criterion. However, on some problems that differences between the demand nodes are covered or the number of nodes each node is large, the method of solving MCLP may ignore these differences. In this paper, Heuristic solution based on the ranking of demands in each node and the number of nodes covered by each node according to a predetermined critical value is proposed. The output of this method is to maximize total demands of nodes and number of covered nodes, simultaneously. Furthermore, by providing an example, the solution algorithm is described and its results are compared with Greedy and Lagrange algorithms. Also, the results of the algorithm to solve the larger problem sizes that compared with other methods are provided. A summary and future works conclude the paper.

Keywords: heuristic solution, maximal covering location problem, ranking, set covering

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Authors: Mahdi Motahari, Mojtaba Farzaneh, Armin Parsian Nejad

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The rapidly growing wind industry is highly expressing the need for education and training worldwide, particularly on the system level. Modelling and simulating wind generator system using Matlab-Simulink provides expert help in understanding wind systems engineering and system design. Working under Matlab-Simulink we present the integration of the developed WECS model with public electrical grid. A test of the calculated power and Cp related to the experimental equivalent data, using statistical analysis is performed. The statistical indicators of accuracy show better results of the presented method with RMSE: 21%, 22%, MBE : 0.77%, 0.12 % and MAE :3%, 4%.On the other hand we study its behavior when integrated in whole power system. Three level of wind speeds have been chosen: low with 5m/s as the mean value, medium with 8m/s as the mean value and high speed with 12m/s as the mean value. These allowed predicting and supervising the active power produced by the system, characterized respectively by the middle powers of -150 kW, -250kW and -480 kW which will be injected directly into the public electrical grid and the reactive power, characterized respectively by the middle powers of 60 kW, 180 kW and 320 kW and will be consumed by the wind generator.

Keywords: modelling, simulation, wind generator, fixed speed wind turbine, Matlab-Simulink

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Authors: Shadi Motamedighazvini, Roohollah Taherkhani, Mahdi Mahdikhani, Najme Hashempour

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Nowadays, green building rating systems are an inevitable necessity for managing environmental considerations to achieve green buildings. The aim of this paper is to deliver a detailed recognition of what has been the focus of green building policymakers around the world; It is important to conduct this study in a way that can provide a context for researchers who intend to establish or upgrade existing rating systems. In this paper, fifteen rating systems including four worldwide well-known plus eleven local rating systems which have been selected based on the answers to the questionnaires were examined. Their similarities and differences in mandatory and prerequisite clauses, highest and lowest scores for each criterion, the most frequent criteria, and most frequent sub-criteria are determined. The research findings indicated that although the criteria of energy, water, indoor quality (except Homestar), site and materials (except GRIHA) were common core criteria for all rating systems, their sub-criteria were different. This research, as a roadmap, eliminates the lack of a comprehensive reference that encompasses the key criteria of different rating systems. It shows the local systems need to be revised to be more comprehensive and adaptable to their own country’s conditions such as climate.

Keywords: environmental assessment, green buildings, green building criteria, green building rating systems, sustainability, rating tools

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Authors: Javad Hesari, Tahereh Donyatalab, Sodeif Azadmard Damirchi, Reza Rezaii Mokaram, Abbas Rafat

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The main objective of this research was to increase shelf life of stirred yoghurt by adding chitosan as a naturally antimicrobial compound. Chitosan were added at different concentrations (0.1, 0.3 and 0.6%) to the stirred yoghurt. Samples were stored at refrigerator and room temperature for 3 weeks and tested with respect of microbial properties (counts of starter bacteria, mold and yeast, coliforms and E. coli). Starter bacteria and yeast counts in samples containing chitosan was significantly (p<0.05) lower than those in control samples and its antibacterial and anti-yeast effects increased with increasing concentration of chitosan. The lowest counts of starter bacteria and yeast were observed at samples whit 0.6% of chitosan. The Results showed Chitosan had a positive effect on increasing shelf life and controlling of yeasts and therefore can be used as a natural preservative in stirred yogurt.

Keywords: chitosan, natural preservative, stirred yoghurt, self-life

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Authors: Arash Rahmani, Ahmad Ghanbari, Abbas Baghernezhad, Babak Safaei

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In the design of parallel manipulators, usually mean value of a dexterity measure over the workspace volume is considered as the objective function to be used in optimization algorithms. The mentioned indexes in a hybrid parallel manipulator (HPM) are quite complicated to solve thanks to infinite solutions for every point within the workspace of the redundant manipulators. In this paper, spatial isotropic design axioms are extended as a well-known method for optimum design of manipulators. An upper limit for the isotropy measure of HPM is calculated and instead of computing and minimizing isotropy measure, minimizing the obtained limit is considered. To this end, two different objective functions are suggested which are obtained from objective functions of comprising modules. Finally, by using genetic algorithm (GA), the best geometric parameters for a specific hybrid parallel robot which is composed of two modified Gough-Stewart platforms (MGSP) are achieved.

Keywords: hybrid manipulator, spatial isotropy, genetic algorithm, optimum design

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Authors: Abbas Moradi, Mohsen Safajoy, Reza Yazdanparast

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Analysis of blade-disc dovetail joints is one of the biggest challenges facing designers of aero-engines. To avoid comparatively expensive experimental full-scale tests, numerical methods can be used to simulate loaded disc-blades assembly. Mortar method provides a powerful and flexible tool for solving frictional contact problems. In this study, 2D frictional contact in dovetail has been analysed based on the mortar algorithm. In order to model the friction, the classical law of coulomb and moving friction cone algorithm is applied. The solution is then obtained by solving the resulting set of non-linear equations using an efficient numerical algorithm based on Newton–Raphson Method. The numerical results show that this approach has better convergence rate and accuracy than other proposed numerical methods.

Keywords: computational contact mechanics, dovetail joints, nonlinear FEM, mortar approach

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Authors: Alireza Vakili, Shahab Ehtesham, Mohsen Danesh Mesgaran, Mahdi Paktinat

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The goal of this study is to determine the chemical compounds of brown Iranian propolis(BIP) extracts and to show flavonoids and phenol effects on nitrogen ammonia (NH3-N) in in vitro. Experimental samples were including two diets with different concentrate: forage ratio (80:20 and 60:40) with eight treatments (1:Control diet 60:40 without BIP,2: 60:40 diet with 25% BIP, 3:60:40 diet with 50% BIP, 4: 60:40 diet with 75% BIP,5: Control diet 80:20 without BIP,6: 80:20 diet with 25% BIP,7: 80:20 diet with 50% BIP and 8: 80:20 diet with 75% BIP) and eight repeats. The trial was analyzed considering a completely randomized design by the GLM procedure of SAS 9.1. Means among treatment were compared by Tukey test. The results of this study showed that in food with 80:20 (concentrate: forage), adding BIP 25% did not statistically change NH3-N (p > 0.05) compared to the control treatment but there was a significant difference (p < 0.05) between the effect of BIP 50% on NH3-N compared to the BIP 25% and the control. In diet with 60:40 (concentrate: forage), there was no significant difference between the effect of BIP 25% on NH3-N and the control, nor was there a significant difference between the effect of BIP 50% and 75%, while a significant difference (p < 0.05) between BIP 50% and 75% and the rest was observed. The propolis extract makes nitrogen ammonia decrease. This may help the nitrogen retain longer in ruminants.

Keywords: brown Iranian propolis, in vitro, nitrogen ammonia, ruminant

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Authors: Marzieh Ebrahimi, Vahid Changizi, Mohammad Reza Kardan, Seyed Mahdi Hosseini Pooya, Parham Geramifar

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Radiation exposure to the patient's family members is one of the major concerns during thyroid cancer radionuclide therapy. The aim of this study was to measure the total effective dose of the family members by means of thermoluminescence personal dosimeter, and compare with those calculated by analytical methods. Eighty-five adult family members of fifty-one patients volunteered to participate in this research study. Considering the minimum and maximum range of dose rate from 15 µsv/h to 120 µsv/h at patients' release time, the calculated mean and median dose values of family members were 0.45 mSv and 0.28 mSv, respectively. Moreover, almost all family members’ doses were measured to be less than the dose constraint of 5 mSv recommended by Basic Safety Standards. Considering the influence parameters such as patient dose rate and administrated activity, the total effective doses of family members were calculated by TEDE and NRC formulas and compared with those of experimental results. The results indicated that, it is fruitful to use the quantitative calculations for releasing patients treated with I-131 and correct estimation of patients' family doses.

Keywords: effective dose, thermoluminescence, I-131, thyroid cancer

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Authors: Abbas Vahedian, Rijun Shrestha, Keith Crews

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In recent years, fibre reinforced polymers as applications of strengthening materials have received significant attention by civil engineers and environmentalists because of their excellent characteristics. Currently, these composites have become a mainstream technology for strengthening of infrastructures such as steel, concrete and more recently, timber and masonry structures. However, debonding is identified as the main problem which limit the full utilisation of the FRP material. In this paper, a preliminary analysis of factors affecting bond strength of FRP-to-concrete and timber bonded interface has been conducted. A novel theoretical method through regression analysis has been established to evaluate these factors. Results of proposed model are then assessed with results of pull-out tests and satisfactory comparisons are achieved between measured failure loads (R² = 0.83, P < 0.0001) and the predicted loads (R² = 0.78, P < 0.0001).

Keywords: debonding, fibre reinforced polymers (FRP), pull-out test, stepwise regression analysis

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Authors: Saud Al Mahdi

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Traditionally,portfolio managers have been discouraged from timing the market. This means, for example, that equity managers have been forced to adhere strictly to a benchmark with static or relatively stable components, such as the SP 500 or the Russell 3000. This means that the portfolio’s exposures to all risk factors should mimic as closely as possible the corresponding exposures of the benchmark. The main risk factor, of course, is the market itself. Effectively, a long-only portfolio would be constrained to have a beta 1. More recently, however, managers have been given greater discretion to adjust their portfolio’s risk exposures (in particular, the beta of their portfolio) dynamically to match the manager’s beliefs about future performance of the risk factors themselves. This freedom translates into the manager’s ability to adjust the portfolio’s beta dynamically. These strategies have come to be known as smart beta strategies. Adjusting beta dynamically amounts to attempting to "time" the market; that is, to increase exposure when one anticipates that the market will rise, and to decrease it when one anticipates that the market will fall. Traditionally, market timing has been believed to be impossible to perform effectively and consistently. Moreover, if a majority of market participants do it, their combined actions could destabilize the market. The aim of this project is to investigate so-called smart beta strategies to determine if they really can add value, or if they are merely marketing gimmicks used to sell dubious investment strategies.

Keywords: beta, alpha, active portfolio management, trading strategies

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Authors: Rami Al Jafar, Paul Elliott, Konstantinos K. Tsilidis, Abbas Dehghan

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Although Ramadan fasting is a ritual that is practiced every year by millions of Muslims, studies on Ramadan fasting are still scarce. To the best of our knowledge, none of the previous studies comprehensively explored the effect on the metabolic profile. In London Ramadan Fasting Study, blood samples were collected from 81 participants before and 10-14 days after Ramadan. Blood samples were analysed using nuclear magnetic resonance (NMR) spectroscopy which covers 249 metabolites. Mixed-effects models were used to analyse collected data and assess the effect of Ramadan fasting on the metabolic profile. Our observational study involved 85 individuals with a mean age of 45.2 years, and 53.1% of them were males. After Ramadan, forty metabolites were affected significantly by Ramadan fasting. Most of these metabolites were metabolites ratios (24), and the rest were three Glycolysis, three ketone bodies, nine Lipoprotein subclasses and one inflammation marker. This study suggests that Ramadan fasting is significantly associated with changes in the metabolic profile. However, the changes are assumed to be temporary, and the long-term effect of these changes is unknown.

Keywords: metabolic profile, Ramadan fasting, metabolites, intermittent fasting

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