Search results for: the density of the direct current

Authors: K. Ighilahriz, M. Taleb Ahmed, R. Maachi

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Oil industries are responsible for most cases of contamination of our ecosystem by oil and heavy metals. They are toxic and considered carcinogenic and dangerous even when they exist in trace amounts. At Algiers refinery, production, transportation, and refining of crude oil generate considerable waste in storage tanks; these residues result from the gravitational settling. The composition of these residues is essentially a mixture of hydrocarbon and lead. We propose in this work the application of electrooxidation treatment for the leachate of the leaden sludge. The effect of pH, current density and the electrolysis time were studied, the effectiveness of the processes is evaluated by measuring the chemical oxygen demand (COD). The dissolution is the best way to mobilize pollutants from leaden mud, so we conducted leaching before starting the electrochemical treatment. The process was carried out in batch mode using graphite anode and a stainless steel cathode. The results clearly demonstrate the compatibility of the technique used with the type of pollution studied. In fact, it allowed COD removal about 80%.

Keywords: electrooxidation, leaching, leaden sludge, oil industry

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Authors: Rama Bhargava

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In the current paper, numerical simulation has been performed for the two-dimensional time dependent Pennes’ heat transfer model which is solved for irregular diseased tumor cells. An elliptic cryoprobe of varying sizes is taken at the center of the computational domain in such a manner that the location of the probe is fixed throughout the computation. The phase transition occurs due to the effect of probe with infusion of different nanoparticles Au, Al₂O₃, Fe₃O₄. The cooling performance of these nanoparticles injected at very low temperature, has been studied by implementing a hybrid FEM/EFGM method in which the whole domain is decomposed into two subdomains. The results are shown in terms of temperature profile inside the computational domain. Rate of cooling is obtained for various nanoparticles and it is observed that infusion of Au nanoparticles is very much efficient in increasing the heating rate than other nanoparticles. Such numerical scheme has direct applications where the domain is irregular.

Keywords: cryosurgery, hybrid EFGM/FEM, nanoparticles, simulation

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Authors: Teng Li, Kamran Mohseni

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This paper presents an inviscid regularization technique that is capable of regularizing the shocks and sharp interfaces simultaneously in the shock-interface interaction simulations. The direct numerical simulation of flows involving shocks has been investigated for many years and a lot of numerical methods were developed to capture the shocks. However, most of these methods rely on the numerical dissipation to regularize the shocks. Moreover, in high Reynolds number flows, the nonlinear terms in hyperbolic Partial Differential Equations (PDE) dominates, constantly generating small scale features. This makes direct numerical simulation of shocks even harder. The same difficulty happens in two-phase flow with sharp interfaces where the nonlinear terms in the governing equations keep sharpening the interfaces to discontinuities. The main idea of the proposed technique is to average out the small scales that is below the resolution (observable scale) of the computational grid by filtering the convective velocity in the nonlinear terms in the governing PDE. This technique is named “observable method” and it results in a set of hyperbolic equations called observable equations, namely, observable Navier-Stokes or Euler equations. The observable method has been applied to the flow simulations involving shocks, turbulence, and two-phase flows, and the results are promising. In the current paper, the observable method is examined on the performance of regularizing shocks and interfaces at the same time in shock-interface interaction problems. Bubble-shock interactions and Richtmyer-Meshkov instability are particularly chosen to be studied. Observable Euler equations will be numerically solved with pseudo-spectral discretization in space and third order Total Variation Diminishing (TVD) Runge Kutta method in time. Results are presented and compared with existing publications. The interface acceleration and deformation and shock reflection are particularly examined.

Keywords: compressible flow simulation, inviscid regularization, Richtmyer-Meshkov instability, shock-bubble interactions.

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Authors: Aina Barcelona, Carolyn Oldham, Jordi Colomer, Jordi Garcia-Orellana, Teresa Serra

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Seagrass meadows increase the sedimentation within the canopy. However, there is still a lack of knowledge about how seagrasses impact the vertical distribution of sediment coming from external sources and reaches the meadow. This study aims to determine the number of particles retained by a seagrass meadow. Based on the hydrodynamics in the vertical direction, a meadow can be separated into different compartments: the blades, the seabed, within the canopy layer, and the above canopy layer. A set of laboratory experiments were conducted under different hydrodynamic conditions and canopy densities with the purpose to mimic the real field conditions. This study demonstrates and quantifies that seagrass meadows decrease the volume of the suspended sediment by two mechanisms: capturing the suspended sediment by the seagrass blades and promoting the particle sedimentation to the seabed. This study also demonstrates that the number of sediment particles trapped by single seagrass blades decreases with canopy density. However, when considering the trapping by the total number of blades, the sediment captured by all the blades of the meadow increases with canopy density. Furthermore, comparing with the bare seabed, this study demonstrated that there is a reduction in the suspended particles within the canopy, which implies an improvement in the water clarity. In addition, the particle sedimentation on the seabed increases with the canopy density compared with the bare seabed, making evident the contribution of the vegetation in enhancing sedimentation.

Keywords: seagrass, sediment capture, turbulent kinetic energy, oscillatory flow

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Authors: Evgeniya Ivanova

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Nowadays, in the literature, there is still no fixed definition of knowledge management that often remains only as an academic discipline. The current market situation is changing very quickly, the need of new technologies is high, and knowledge management is the area that ensures that the know-how has not been lost during market development and adoption. The study examines how knowledge management is being leveraged and practiced in the management consultancy companies and provides not only the tips and best practices of applied knowledge management approaches but also the validation matrix for its successful or unsuccessful implementation. Different knowledge management approaches are explored on the basis of their practical implementation, including related challenges, knowledge sharing process, and barriers that are typical for consulting firms mostly driven by the agile working culture. The relevance of proposed topic is confirmed by the finding that corporate working culture and the exponentially developing technologies have a direct impact on the success of practical implementation of knowledge management.

Keywords: knowledge management, knowledge management in practice, consulting firm, knowledge management success

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Authors: Sunday Sedodo Nupo, Clara Berstien Oguntona, Babatunde Oguntona, Oluseyi Akinloye, P. A. Olunusi Adeboye

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Cardiovascular diseases are now becoming dominant sources of morbidity and mortality worldwide. This study investigated the lipid profile of civil servants. A cross-sectional study was carried out among randomly selected 202 male and 298 female civil servants in Abeokuta Ogun state. A pretested structured questionnaire was used to elicit information on history of non-communicable diseases and physical activity pattern of the respondents. The blood pressures of the subjects were measured and classified using World Health Organization criteria. The total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL). Ethical approval was obtained from Ogun State Ministry of Health. Data collected were analysed using Statistical package for social science version 17.1. Results showed that majority (76%) of the subjects were within the age range of 20 - 40 years, 75% earned between N58,500 - N98,000 monthly and 68% were sedentary. The mean energy intake of men and women were 3942±38 kcal and 2791±3 kcal respectively, while the protein intake for men was 65±49 g/day and 54.28±40 g/day for women. Desirable TC level (<200 mg/dl) was found in 80% of the selected subjects while the normal TG (<150 mg/dl) and LDL (<129 mg/dl) was found in 95% and 90% subjects respectively. The mean TC was 78.91±11 mg/dl and 62.69±9 mg/dl in men and women respectively. The study showed that most of the subjects had normal lipid in terms of serum triglycerides, total cholesterol, HDL cholesterol and LDL cholesterol.

Keywords: high density lipoprotein, morbidity, mortality, triglycerides

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Authors: Norman Sinnigen, Igor Izyurov, Marina Krylova, Hamidreza Jamalabadi, Sarah Alizadeh, Martin Walter

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Background: EEG is a non-invasive brain activity recording technique with a high temporal resolution that allows the use of real-time applications, such as neurofeedback. However, EEG data are susceptible to electrooculographic (EOG) and electromyography (EMG) artifacts (i.e., jaw clenching, teeth squeezing and forehead movements). Due to their non-stationary nature, these artifacts greatly obscure the information and power spectrum of EEG signals. Many EEG artifact correction methods are too time-consuming when applied to low-density EEG and have been focusing on offline processing or handling one single type of EEG artifact. A software-only real-time method for correcting multiple types of EEG artifacts of high-density EEG remains a significant challenge. Methods: We demonstrate an improved approach for automatic real-time EEG artifact correction of EOG and EMG artifacts. The method was tested on three healthy subjects using 64 EEG channels (Brain Products GmbH) and a sampling rate of 1,000 Hz. Captured EEG signals were imported in MATLAB with the lab streaming layer interface allowing buffering of EEG data. EMG artifacts were detected by channel variance and adaptive thresholding and corrected by using channel interpolation. Real-time independent component analysis (ICA) was applied for correcting EOG artifacts. Results: Our results demonstrate that the algorithm effectively reduces EMG artifacts, such as jaw clenching, teeth squeezing and forehead movements, and EOG artifacts (horizontal and vertical eye movements) of high-density EEG while preserving brain neuronal activity information. The average computation time of EOG and EMG artifact correction for 80 s (80,000 data points) 64-channel data is 300 – 700 ms depending on the convergence of ICA and the type and intensity of the artifact. Conclusion: An automatic EEG artifact correction algorithm based on channel variance, adaptive thresholding, and ICA improves high-density EEG recordings contaminated with EOG and EMG artifacts in real-time.

Keywords: EEG, muscle artifacts, ocular artifacts, real-time artifact correction, real-time ICA

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Authors: A. Boumedine, K. Benfriha, S. Lecheb

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Manufacturing methods for products and structures made of composite materials reduce the number of parts and integrate technical functions, this advantage of composite materials leads to a lot of innovation but also to a reduction of costs and a gain in quality. A material has attributes: its density, it’s resistance, it’s cost, it’s resistance to corrosion. For the design of a product, a certain profile of these attributes is required: low density, resistance removed, low cost. The problem is then to identify this attribute profile and to compare it with those of the materials, in order to find the one that comes closest. The aim of this work is to demonstrate the feasibility of characterizing a mini turbine made of 3D printed fiber-filled composite material by the process of additive manufacturing, then compare the performance of the alloy turbine with the composite turbine according to the results of the simulation by Abaqus software.

Keywords: additive manufacturing, composite materials, design, 3D printer, turbine

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Authors: Mariola Głowacka

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The aim of the study was to determine the level of adaptation to the current health situation and its impact on the adherence state of people in the pre- and senior age. The work covers the results of the first of the fourteen parts of the study conducted in a group of 2,000 people aged 55 plus. This part of the project was carried out with the use of two standardized tools: the HLC adaptation scale (the health locus of control scale and The Adherence in Chronic DiseasesScale (ACDS). The obtained results showed the range of influence of particular areas of self-acceptance of the health state (health and disease) on their adherence, taking into account specific clinical conditions.

Keywords: adaptation to the current health situation, adherence, senior, badania

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Authors: Marina Lazar Chandy, N. Kannan, Rajendra Patil, Vinod Mathew, Ajmal Mohamed, P. K. Sreeja, Renju Jose

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Introduction- Arecoline, a major constituent of arecanut has shown to have some effect on liver. The use of arecanut is found to be the most common etiological factor for the development of Oral Submucous fibrosis (O.S.M.F). The effect of arecanut usage on liver in patients with O.S.M.F needs to be assessed. Lipids play a role in structural maintenance of cell. Alterations of lipid profile were noted in cancer patients. O.S.M.F being a precancerous lesion can have some effect on the level of lipids in the body. Objectives: This study was done to assess the alterations in liver enzymes (Serum Glutamic Pyruvic Transaminase(S.G.P.T ,Serum Glutamic Oxaloacetic Transaminase(S.G.O.T)) and lipid metabolism (High Density Lipoprotien(H.D.L) and Apo Lipoprotien A1 (Apo A1)) in patients with O.S.M.F. Methods-130 patients were taken for the study,100 patients with O.S.M.F and 30 as control group without O.S.M.F. Fasting blood sugar levels were taken, centrifuged and analyzed for S.G.P.T,S.G.O.T, H.D.L and Apo A1 using semi automated spectrophotometer. Results: After statistical analysis, it was concluded that there is an elevation of levels of S.G.P.T, S.G.O.T, and decreased levels of H.D.L, Apo A1 for O.S.M.F group when compared with control group. With increased grade of O.S.M.F. and duration of habit, S.G.P.T. & S.G.O.T. increased whereas, H.D.L. & Apo A1 decreased. All the values were statistically significant at p<0.01.

Keywords: apolipoprotien A1, high density lipoprotien, oral submucous fibrosis, serum glutamic oxaloacetic transaminase

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Authors: Samira Abbaspour

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Soil contamination by oil industry is unavoidable issue; irrespective of environmental impact, which occurs during the process of soil contaminating and remediating. Effect of this phenomenon on the geotechnical properties of the soil has not been investigated thoroughly. Some researchers studied the environmental aspects of these phenomena more than geotechnical point of view. In this research, compaction and unconfined compression tests were conducted on samples of natural, contaminated and treated soil after 50 days of bio-treatment. The results manifest that increasing the amount of crude oil, leads to decreased values of maximum dry density and optimum water content and increased values of unconfined compression strength (UCS). However, almost 65% of this contamination terminated by using a Bioremer as a bioremediation agent. Foremost, as bioremediation takes place, values of maximum dry density, unconfined compression strength and failure strain increase.

Keywords: contamination, shear strength, compaction, oil contamination

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Authors: Rachid El Khoury

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Chronic pain is perhaps the most burdensome health issue facing the planet. Our understanding of the pathophysiology of chronic pain has increased substantially over the past 25 years, including but not limited to changes in the brain. However, we still do not know why chronic pain develops in some people and not in others. Most of the recent developments in pain science, that have direct relevance to clinical management, relate to our understanding of the role of the brain, the role of the immune system, or the role of cognitive and behavioral factors. Although the Biopsychosocial model of pain management was presented decades ago, the Bio-reductionist model remains, unfortunately, at the heart of many practices across professional and geographic boundaries. A large body of evidence shows that nociception is neither sufficient nor necessary for pain. Pain is a conscious experience that can certainly be, and often is, associated with nociception, however, always modulated by countless neurobiological, environmental, and cognitive factors. This study will clarify the current misconceptions of chronic pain concepts, and their misperceptions by clinicians. It will also attempt to bridge the considerable gap between what we already know on pain but somehow disregarded, the development in pain science, and clinical practice.

Keywords: chronic pain, nociception, biopsychosocial, neuroplasticity

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Authors: Martin Adlington, Boris Ceranic, Sally Shazhad

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In an effort to reduce carbon emissions, changes in UK regulations, such as Part L Conservation of heat and power, dictates improved thermal insulation and enhanced air tightness. These changes were a direct response to the UK Government being fully committed to achieving its carbon targets under the Climate Change Act 2008. The goal is to reduce emissions by at least 80% by 2050. Factors such as climate change are likely to exacerbate the problem of overheating, as this phenomenon expects to increase the frequency of extreme heat events exemplified by stagnant air masses and successive high minimum overnight temperatures. However, climate change is not the only concern relevant to overheating, as research signifies, location, design, and occupation; construction type and layout can also play a part. Because of this growing problem, research shows the possibility of health effects on occupants of buildings could be an issue. Increases in temperature can perhaps have a direct impact on the human body’s ability to retain thermoregulation and therefore the effects of heat-related illnesses such as heat stroke, heat exhaustion, heat syncope and even death can be imminent. This review paper presents a comprehensive evaluation of the current literature on the causes and health effects of overheating in buildings and has examined the differing applied assessment approaches used to measure the concept. Firstly, an overview of the topic was presented followed by an examination of overheating research work from the last decade. These papers form the body of the article and are grouped into a framework matrix summarizing the source material identifying the differing methods of analysis of overheating. Cross case evaluation has identified systematic relationships between different variables within the matrix. Key areas focused on include, building types and country, occupants behavior, health effects, simulation tools, computational methods.

Keywords: overheating, climate change, thermal comfort, health

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Authors: Aleh Meshyk, Anastasiya Vouchak

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On the average snow covers Belarus for 75 days in the south-west and 125 days in the north-east. During the cold season snowpack often destroys due to thaws, especially at the beginning and end of winter. Over 50% of thawing days have a positive mean daily temperature, which results in complete snow melting. For instance, in December 10% of thaws occur at 4 С mean daily temperature. Stable snowpack lying for over a month forms in the north-east in the first decade of December but in the south-west in the third decade of December. The cover disappears in March: in the north-east in the last decade but in the south-west in the first decade. This research takes into account that precipitation falling during a cold season could be not only liquid and solid but also a mixed type (about 10-15 % a year). Another important feature of snow cover is its density. In Belarus, the density of freshly fallen snow ranges from 0.08-0.12 g/cm³ in the north-east to 0.12-0.17 g/cm³ in the south-west. Over time, snow settles under its weight and after melting and refreezing. Averaged annual density of snow at the end of January is 0.23-0.28 g/сm³, in February – 0.25-0.30 g/сm³, in March – 0.29-0.36 g/сm³. Sometimes it can be over 0.50 g/сm³ if the snow melts too fast. The density of melting snow saturated with water can reach 0.80 g/сm³. Average maximum of snow depth is 15-33 cm: minimum is in Brest, maximum is in Lyntupy. Maximum registered snow depth ranges within 40-72 cm. The water content in snowpack, as well as its depth and density, reaches its maximum in the second half of February – beginning of March. Spatial distribution of the amount of liquid in snow corresponds to the trend described above, i.e. it increases in the direction from south-west to north-east and on the highlands. Average annual value of maximum water content in snow ranges from 35 mm in the south-west to 80-100 mm in the north-east. The water content in snow is over 80 mm on the central Belarusian highland. In certain years it exceeds 2-3 times the average annual values. Moderate water content in snow (80-95 mm) is characteristic of western highlands. Maximum water content in snow varies over the country from 107 mm (Brest) to 207 mm (Novogrudok). Maximum water content in snow varies significantly in time (in years), which is confirmed by high variation coefficient (Cv). Maximums (0.62-0.69) are in the south and south-west of Belarus. Minimums (0.42-0.46) are in central and north-eastern Belarus where snow cover is more stable. Since 1987 most gauge stations in Belarus have observed a trend to a decrease in water content in snow. It is confirmed by the research. The biggest snow cover forms on the highlands in central and north-eastern Belarus. Novogrudok, Minsk, Volkovysk, and Sventayny highlands are a natural orographic barrier which prevents snow-bringing air masses from penetrating inside the country. The research is based on data from gauge stations in Belarus registered from 1944 to 2014.

Keywords: density, depth, snow, water content in snow

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Authors: Seyedeh Faranak Baniahmad, Soroor Yousefi

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Osteoporosis is a bone disease which increases the bone fracture risk, reduces the bone mineral density (BMD) and alters the amount and variety of proteins in bones. Antiresorptive therapy is one the most popular Osteoporosis treatment methods. In this method the bisphosphonates, hormones, calcitonin or the selective estrogen receptor modulators is replaced. In order to reduce undesirable effects and to increase the bioavailability of drug agents, the controlled drug delivery systems have been utilized. In current study, the controlled release of Alendronate from LDH-PCL with (0, 5, 10, 15 % wt. of LDH) was investigated. The results showed that the release of alendronate from the lamellar LDH incorporated into the PCL matrix is much slower than the release of alendronate from the PCL. Therefore such systems are very promising, in which the antiresorptive drug has to remain in the matrix for longer time and can be released in controlled manner.

Keywords: osteoporosis, alendronate, poly (ε–caprolactone), layered double hydroxide

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Authors: Amirreza Heidari, Akram Avami, Ehsan Heidari

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Evaporative cooling systems are known as energy efficient cooling systems, with much lower electricity consumption than conventional vapor compression systems. A serious limitation of these systems, however, is that they are not applicable in humid regions. Combining a desiccant wheel with these systems, known as desiccant-based evaporative cooling systems, makes it possible to use evaporative cooling in humid climates. This paper evaluates the performane of a cooling system combining desiccant wheel, direct and indirect evaporative coolers (called desiccant-based indirect-direct evaporative cooling (DIDE) system) and then evaluates the energy saving potential of this system over the conventional vapor compression cooling and drying system. To illustrate the system ability of providing comfort conditions, a dynamic hourly simulation of this system is performed for a typical 60 m² building in Sydney, Australia. To evaluate the energy saving potential of this system, a conventional cooling and drying system is also simulated for the same cooling capacity. It has been found that the DIE system is able to provide comfort temperature and relative humidity in a subtropical humid climate like Sydney. The electricity and natural gas consumption of this system are respectively 39.2% and 2.6% lower than that of conventional system over a week. As the research has demonstrated, the innovative DIDE system is an energy efficient cooling system for subtropical humid regions.

Keywords: desiccant, evaporative cooling, dehumidification, indirect evaporative cooler

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Authors: Gilbert Omorodion Osayemwenre, Edson Meyer, R. T. Taziwa

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The electrical analysis of single junction amorphous silicon solar modules is carried out using outdoor monitoring technique. Like crystalline silicon PV modules, the electrical characterisation and performance of single junction amorphous silicon modules are best described by its current-voltage (IV) characteristic. However, IV curve has a direct dependence on the type of PV technology and material properties used. The analysis reveals discrepancies in the modules performance parameter even though they are of similar technology. The aim of this work is to compare the electrical performance output of each module, using electrical parameters with the aid of PVPM 100040C IV tracer. These results demonstrated the relevance of standardising the performance parameter for effective degradation analysis of a-Si:H.

Keywords: PVPM 100040C IV tracer, SolarWatt part, single junction amorphous silicon module (a-Si:H), Staebler-Wronski (S-W) degradation effect

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Authors: Chul H. Jo, Do Y. Kim, Bong K. Cho, Myeong J. Kim

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The exhaustion of oil and the environmental pollution from the use of fossil fuel are increasing. Tidal current power (TCP) has been proposed as an alternative energy source because of its predictability and reliability. By applying a duct and single point mooring (SPM) system, a TCP device can amplify the generating power and keep its position properly. Because the generating power is proportional to cube of the current stream velocity, amplifying the current speed by applying a duct to a TCP system is an effective way to improve the efficiency of the power device. An SPM system can be applied at any water depth and is highly cost effective. Simple installation and maintenance procedures are also merits of an SPM system. In this study, we designed an SPM system for a duct-type TCP device for use in shallow water. Motions of the duct are investigated to obtain the response amplitude operator (RAO) as the magnitude of the transfer function. Parameters affecting the stability of the SPM system such as the fairlead departure angle, current velocity, and the number of clamp weights are analyzed and/or optimized. Wadam and OrcaFlex commercial software is used to design the mooring line.

Keywords: mooring design, parametric analysis, RAO (Response Amplitude Operator), SPM (Single Point Mooring)

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Authors: Matthew Ocheleka Itodo, Ogo Agbo Ogo, Agnes Ogbene Abutu, Bawa Inalegwu

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Hyperlipidemia is characterised by elevated serum total cholesterol and low density and very low-density lipoprotein cholesterol and decreased high-density lipoprotein are the risk factor for coronary heart diseases. There are claims by traditional medicine practitioners in Nigeria that Moringa oleifera plants are used for the treatment of cardiovascular diseases, but it appears there is no scientific research and, publication or documented work to verify these claims. This study aimed to determine the effect of methanol root extracts of Moringa oleifera on Lipid profile, Atherogenic indices and 3 hydroxyl 3 methylglutaryl Coenzyme A reductase activity of poloxamer 407-induced hyperlipidemic rats. The animals were grouped into 8; Group 1: Normal control, Group 2: Hyperlipidemic control. Groups 2 to 8 were induced with Poloxamer 407 1000 mg/Kg body weight. However, group 3 were treated with standard drugs (atorvastatin). Group 4 was treated with crude extract, and groups 5 to 8 were treated with purified fractions from column chromatography. The preliminary antihyperlipidemic study showed Methanol root extract at 200 mg/kg body weight significantly (p≤0.05) decreased total cholesterol, low-density lipoprotein, triacylglyceride, 3 hydroxyls 3 methylglutaryl Coenzyme A reductase, and increase high-density lipoprotein of hyperlipidemic treated groups. Screening the extracts for the most potent anti-hyperlipidemic activity reveals that fraction 1 of Total Cholesterol and Fraction 3 of Triacylglyceride have the highest percentage reduction of 56% and 51%, respectively. The atherogenic risk factor of all induced treated rats shows a significant (p<0.05) decrease in levels of Castelli’s risk index II, atherogenic index of plasma and a significant (p<0.05) higher level of Castelli’s risk index I ratio. The study shows that the methanol extract of root possesses antihyperlipidemic effects and may explain why it has been found to be useful in the management of cardiovascular diseases by traditional medicine practitioners.

Keywords: hyperlipidemia, moringa oleifera, poloxamer 407, lipid profile

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Authors: Farid Rezaei, Zahra Reza Soltani, Behrouz Tavana, Afsaneh Dadarkhah, Masoume Bahrami Asl, S. Alireza Mirghasemi

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Introduction: Fibromyalgia is a syndrome comprised of a group of symptoms. The primary symptom of fibromyalgia is pain propagation is associated by Secondary symptoms include fatigue, cognitive disorders, sleep disorders and hypersensitivity to painful stimuli. Recent studies have shown that there is a direct relationship between fibromyalgia and certain changes in brain activity. Aim: The aim of this study is determining the effect of tDCS in pain and quality of life in patients with fibromyalgia. Method: 68 patients with fibromyalgia who had inclusion criterias were randomly divided into two groups of case and control. Groups were matched in terms of gender, age, education, duration of pain and PMS. Patient groups treated with tDCS device manufacture by Enraf company made in Netherlands (M1 anodal stimulation, 2 mA constant current, 20 minutes, for 10 sessions (3 days a week)). Also the protocol was done for control group, in sham mode of tDCS device that had no current, for 10 sessions of 20 minutes. Before treatment, immediately after the end of 10 sessions treatment (short-term) and 10 week later (long-term effect), pain intensity questionnaires (VAS) and quality of life in fibromyalgia patients questionnaire was completed by the patient. Results: Pain intensity were significantly lower in the treatment group than the sham group 2 weeks and 10 weeks after treatment than before treatment (P < 0.001). Although the quality of life of patients 2 weeks after treatment showed no significant change, but ten weeks after treatment were more than sham group (P < 0.0001). Conclusion: Our results suggest that tDCS is a safe and effective in treating fibromyalgia patients and an important effect in reducing pain and increasing quality of their life.

Keywords: fibromyalgia, tDCS, quality of life, VAS score

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Authors: Simon Guerin-Marthe, Marie Violay

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Thermal Pressurization (TP) has been proposed as a key mechanism involved in the weakening of faults during dynamic ruptures. Theoretical and numerical studies clearly show how frictional heating can lead to an increase in pore fluid pressure due to the rapid slip along faults occurring during earthquakes. In addition, recent laboratory studies have evidenced local pore pressure or local temperature variation during rotary shear tests, which are consistent with TP theoretical and numerical models. The aim of this study is to complement previous ones by measuring both local pore pressure and local temperature variations in the vicinity of a water-saturated calcite gouge layer subjected to a controlled slip velocity in direct double shear configuration. Laboratory investigation of TP process is crucial in order to understand the conditions at which it is likely to become a dominant mechanism controlling dynamic friction. It is also important in order to understand the timing and magnitude of temperature and pore pressure variations, to help understanding when it is negligible, and how it competes with other rather strengthening-mechanisms such as dilatancy, which can occur during rock failure. Here we present unique direct measurements of temperature and pressure variations during high-speed friction experiments under various load point velocities and show the timing of these variations relatively to the slip event.

Keywords: thermal pressurization, double-shear test, high-speed friction, dilatancy

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Authors: E.George, P. Ojeaga, O. Matthew, A. Adekola

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Can foreign direct investment (FDI), promote growth in Africa? What does the inflow of investment hold for African emerging economies? Are the determinants of FDI different for different regional blocs in Africa? This study reviews the implication of FDI for different regional blocs in Africa. FDI was found to have a significant effect on growth in North Africa but had no significant effect in East, Southern and West Africa. FDI was also found not to be driving growth in the whole of Africa in a significant manner. The implications of the findings are that even though trade openness seems to be a major factor driving FDI. Poor domestic markets were still preventing many African economies from taking full advantage of the gains from foreign direct investment. The study results could be useful to scholars who study the dynamics surrounding FDI disbursement and strategies on how FDI can drive growth in developing countries.

Keywords: Africa, political economy, FDI, regional policy, markets

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Authors: C. Boubechou, A. Bouchoucha, H. Zaidi

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The aim of this paper is to study the tribological behavior of a dynamic contact steel-brass couple with electric current. This study looks at a dry contact brass-steel couple where friction and wear are studied in terms of mechanical and electrical parameters. For this reason, a tribometer, pin-rotary disc is used in an atmospheric atmosphere. The test parameters are as follows: the normal load (5-30N), the sliding speed (0.1 to 0.5 m / s) and the electric current (3-10A). The duration of each test is 30 minutes. The experimental results show that these parameters have a significant effect on the tribological behavior of the couple studied. The discussion of results is based on observations, using an optical microscope, MEB and a profilometer, worn surfaces and interface phenomena resulting from the process of sliding contact.

Keywords: brass-steel couple, dry friction, electrical current, morphology, normal load, sliding speeds, wear

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Authors: Hiroyuki Aoki

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The glass transition phenomenon has been extensively studied for a long time. The glass transition of polymer materials is assigned to the transition of the dynamics of the chain backbone segment. However, the detailed mechanism of the transition behavior of the segmental motion is still unclear. In the current work, the single molecule detection technique was employed to reveal the trajectory of the molecular motion of the single polymer chain. The center segment of poly(butyl methacrylate) chain was labeled by a perylenediimide dye molecule and observed by a highly sensitive fluorescence microscope in a defocus condition. The translational and rotational diffusion of the center segment in a single polymer chain was analyzed near the glass transition temperature. The direct observation of the individual polymer chains revealed the intermittent behavior of the segmental motion, indicating the spatial inhomogeneity.

Keywords: glass transition, molecular motion, polymer materials, single molecule

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Authors: Ijaz Ahmed Khan, Zaheen Ullah, Rahamdad, Gul Hassan

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A field experiment was conducted at Agricultural Research Station Ahmad Wala, Karak, Khyber Pakhtunkhwa Province during rabi season of 2010-011 to study the effect of different weed management practices on weed control in chickpea under field conditions. The results revealed that treatments showed significant influence on weed density, seed yield kg ha-1 and other growth parameters. Significantly lower weed density (98 m-2) was recorded with the application of Isoproturon 500 EW as compared to control plots having 368.3 weeds m-2. Moreover, significantly highest seed yield (1583.3 kg ha-1) was produced in the plots assigned with Isoproturon 500 EW followed by Eucalyptus extract that produce seed yield of 1416.7 kg ha-1. It was concluded from the study that Isoproturon 500 EW is the best option for controlling weeds and increase the seed yield kg ha-1 of chickpea.

Keywords: chickpea, herbicides, weed control, weeds extracts

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Authors: Hilal Köse, Şeyma Dombaycıoğlu, Ali Osman Aydın, Hatem Akbulut

Abstract:

Rechargeable lithium-ion batteries (LIBs) have become promising power sources for a wide range of applications, such as mobile communication devices, portable electronic devices and electrical/hybrid vehicles due to their long cycle life, high voltage and high energy density. Graphite, as anode material, has been widely used owing to its extraordinary electronic transport properties, large surface area, and high electrocatalytic activities although its limited specific capacity (372 mAh g-1) cannot fulfil the increasing demand for lithium-ion batteries with higher energy density. To settle this problem, many studies have been taken into consideration to investigate new electrode materials and metal oxide/graphene composites are selected as a kind of promising material for lithium ion batteries as their specific capacities are much higher than graphene. Among them, SnO₂, an n-type and wide band gap semiconductor, has attracted much attention as an anode material for the new-generation lithium-ion batteries with its high theoretical capacity (790 mAh g-1). However, it suffers from large volume changes and agglomeration associated with the Li-ion insertion and extraction processes, which brings about failure and loss of electrical contact of the anode. In addition, there is also a huge irreversible capacity during the first cycle due to the formation of amorphous Li₂O matrix. To obtain high capacity anode materials, we studied on the synthesis and characterization of SnO₂-Graphene nanocomposites and investigated the capacity of this free-standing anode material in this work. For this aim, firstly, graphite oxide was obtained from graphite powder using the method described by Hummers method. To prepare the nanocomposites as free-standing anode, graphite oxide particles were ultrasonicated in distilled water with SnO2 nanoparticles (1:1, w/w). After vacuum filtration, the GO-SnO₂ paper was peeled off from the PVDF membrane to obtain a flexible, free-standing GO paper. Then, GO structure was reduced in hydrazine solution. Produced SnO2- graphene nanocomposites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD) analyses. CR2016 cells were assembled in a glove box (MBraun-Labstar). The cells were charged and discharged at 25°C between fixed voltage limits (2.5 V to 0.2 V) at a constant current density on a BST8-MA MTI model battery tester with 0.2C charge-discharge rate. Cyclic voltammetry (CV) was performed at the scan rate of 0.1 mVs-1 and electrochemical impedance spectroscopy (EIS) measurements were carried out using Gamry Instrument applying a sine wave of 10 mV amplitude over a frequency range of 1000 kHz-0.01 Hz.

Keywords: SnO₂-graphene, nanocomposite, anode, Li-ion battery

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Authors: Azzouzi Fadoua

Abstract:

This study focuses on the diagnosis of the dynamics of natural resources in a semi-arid mountainous weakened by natural vulnerability and anthropogenic action. This is evident in the forms of hydraulic erosion and degradation of agricultural land. The rate of this damaged land is 53%, with a strong presence of concentrated erosion; this shows that balanced and semi-balanced environments are less apparent to the Watershed, representing 47%. The results revealed the crucial role of the slopes and the density of the hydraulic networks to facilitate the transport of fine elements, at the level of the slopes with low vegetation intensity, to the lake of the dam. Something that endangers the siltation of the latter. After the study of natural and anthropogenic elements, it turned out that natural vulnerability is an integral part of the current dynamic, especially when it coincides with the overexploitation of natural resources, in this case, the exploitation of steep slopes for the cultivation of cereals and overgrazing. This causes the soil to pile up and increase the rate of runoff.

Keywords: watershed, erosion, natural vulnerability, anthropogenic

Procedia PDF Downloads 134

Authors: Murat Erdoğdu, Murat Koçyiğit

Abstract:

Brand image and brand loyalty are among the most important relational marketing elements for brand owners to be able to set up long – term relationships with their customers and to maintain these relationships. Brand owners improve their brand images with the positive perceptions remaining in the consumers’ minds. In addition, they try to find the customers that are both emotionally and behaviourally faithful to themselves in order to set up long – term relationships. Therefore, the aim of this study is to analyse the effects of the brand image that has a very important role among relational marketing elements on the brand loyalty in terms of the variables such as the perceived value, the trust in brand and the brand satisfaction. In this context, a conceptual model was created to determine the effect of the brand image on the brand loyalty thanks to the Structural Equation Model (SEM). According to this aim and this model, the study was carried out in the scope of the data collected through the questionnaires in Konya with the method of convenience sampling. The results of the research showed that the brand image has positive significant effects on the perceived value and the trust in brand and that the trust in brand has positive significant effects on the brand satisfaction, and that the brand satisfaction has positive significant effects on the brand loyalty. Thus, the hypotheses that the brand image has direct effects on the perceived value and the trust in brand and that the trust in brand has direct effects on the brand satisfaction and that the brand satisfaction has direct effects on the brand loyalty were supported. In addition, the findings about whether the perceived value has a significant effect on the brand satisfaction were also acquired.

Keywords: brand image, brand loyalty, perceived value, satisfaction, trust

Procedia PDF Downloads 432

Authors: Kadda Amara, Mohammed Elkeurti, Mostefa Zemouli, Yassine Benallou

Abstract:

In this work, we present a study of the structural, elastic and electronic properties of the cubic antiperovskites XNMg3 (X=P, As, Sb and Bi) using the full-potential augmented plane wave plus local orbital (FP-LAPW+lo) within the Generalized Gradient Approximation based on PBEsol, Perdew 2008 functional. We determined the lattice parameters, the bulk modulus B and their pressure derivative B'. In addition, the elastic properties such as elastic constants (C11, C12 and C44), the shear modulus G, the Young modulus E, the Poisson's ratio ν and the B/G ratio are also given. For the band structure, density of states and charge density the exchange and correlation effects were treated by the Tran-Blaha modified Becke-Johnson potential to prevent the shortcoming of the underestimation of the energy gaps in both LDA and GGA approximations. The obtained results are compared to available experimental data and to other theoretical calculations.

Keywords: XNMg3 compounds, GGA-PBEsol, TB-mBJ, elastic properties, electronic properties

Procedia PDF Downloads 395

Authors: Faramarz Ashenai Ghasemi, Ismail Ghasemi, Sajad Daneshpayeh

Abstract:

In this study, tensile strength and elastic modulus of nanocomposites based on polypropylene/ linear low density polyethylene/ nano titanium dioxide (PP/LLDPE/TiO2) were studied. The samples were produced using a co-rotating twin screw extruder including 0, 2, 4 Wt .% of nano particles, and 20, 40, 60 Wt.% of LLDPE. The styrene-ethylene-butylene-styrene (SEBS) was used as comptabiliser. Tensile strength and elastic modulus were evaluated. The results showed that modulus was increased by 7% with addition of nano particles in comparison to PP/LLDPE. In addition, tensile strength was decreased.

Keywords: PP/LLDPE/TiO2, nanocomposites, elastic modulus, tensile strength

Procedia PDF Downloads 520