Search results for: ME coupling coefficient

Authors: Amir Davood Elmi

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From the earliest light microscope to the most innovative X-ray imaging techniques, all of them have refined and improved our knowledge about the organization and composition of living tissues. The old techniques are time consuming and ultimately destructive to the tissues under the examination. In recent few decades, thanks to the boost of technology, non-destructive visualization techniques, such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), selective plane illumination microscopy (SPIM), and optical projection tomography (OPT), have come to the forefront. Among these techniques, CT is excellent for mineralized tissues such as bone or dentine. In addition, CT it is faster than other aforementioned techniques and the sample remains intact. In this article, applications, advantages, and limitations of micro-CT is discussed, in addition to some information about micro-CT of soft tissue.

Keywords: Micro-CT, hard tissue, bone, attenuation coefficient, rapid prototyping

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Authors: Homyr L. Garcia, Jr., Anne Margaret A. Rendon, Carla Michaela B. Taguinod

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Nothing is constant in this world but change. This is the reality wherein a lot of people fail to recognize and maybe, it is because of the fact that some see things that are happening with little value or no value at all until it’s gone. For the past years, Egypt was known for its stable government. It was able to withstand a lot of problems and crisis which challenged their country in ways which can never be imagined. In the present time, it seems like in just a snap of a finger, the said stability vanished and it was immediately replaced by a crisis which resulted to a failure in some parts of their government. In addition, this problem continued to worsen and the current situation of Egypt is just a reflection or a result of it. On the other hand, as the researchers continued to study the reasons why the government of Egypt is unstable, they concluded that there might be a possibility that they will be able to produce ways in which their country could be helped or improved. The instability of the government of Egypt is the product of combining all the problems which affects the lives of the people. Some of the reasons that the researchers found are the following: 1) unending doubts of the people regarding the ruling capacity of elected presidents, 2) removal of President Mohamed Morsi in position, 3) economic crisis, 4) a lot of protests and revolution happened, 5) resignation of the long term President Hosni Mubarak and 6) the office of the President is most likely available only to the chosen successor. Also, according to previous researches, there are two plausible scenarios for the instability of Egypt: 1) a military intervention specifically the Supreme Council of the Armed Forces or SCAF, resulting from a contested succession and 2) an Islamist push for political power which highlights the claim that religion is a hindrance towards the development of their country and government. From the eight possible reasons, the researchers decided that they will be focusing on economic crisis since the instability is more clearly seen in the country’s economy which directly affects the people and the government itself. In addition, they made a hypothesis which states that stable economy is a prerequisite towards a stable government. If they will be able to show how this claim is true by using the Social Autopsy Research Design for the qualitative method and Pearson’s correlation coefficient for the quantitative method, the researchers might be able to produce a proposal on how Egypt can stabilize their government and avoid such problems. Also, the hypothesis will be based from the Rational Action Theory which is a theory for understanding and modeling social and economy as well as individual behavior.

Keywords: Pearson’s correlation coefficient, rational action theory, social autopsy research design, supreme council of the armed forces (SCAF)

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Authors: Ismail Al-Yahmadi, Abbasher Gismelseed, Fatma Al-Mammari, Ahmed Al-Rawas, Ali Yousif, Imaddin Al-Omari, Hisham Widatallah, Mohamed Elzain

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The influence of Fe-doping on the structural, magnetic and magnetocaloric properties of Nd₀.₆Sr₀.₄FeₓMn₁₋ₓO₃ (0≤ x ≤0.5) were investigated. The samples were synthesized by auto-combustion Sol-Gel method. The phase purity, crystallinity, and the structural properties for all prepared samples were examined by X-ray diffraction. XRD refinement indicates that the samples are crystallized in the orthorhombic single-phase with Pnma space group. Temperature dependence of magnetization measurements under a magnetic applied field of 0.02 T reveals that the samples with (x=0.0, 0.1, 0.2 and 0.3) exhibit a paramagnetic (PM) to ferromagnetic (FM) transition with decreasing temperature. The Curie temperature decreased with increasing Fe content from 256 K for x =0.0 to 80 K for x =0.3 due to increasing of antiferromagnetic superexchange (SE) interaction coupling. Moreover, the magnetization as a function of applied magnetic field (M-H) curves was measured at 2 K, and 300 K. the results of such measurements confirm the temperature dependence of magnetization measurements. The magnetic entropy change|∆SM | was evaluated using Maxwell's relation. The maximum values of the magnetic entropy change |-∆SMax |for x=0.0, 0.1, 0.2, 0.3 are found to be 15.35, 5.13, 3.36, 1.08 J/kg.K for an applied magnetic field of 9 T. Our result on magnetocaloric properties suggests that the parent sample Nd₀.₆Sr₀.₄MnO₃ could be a good refrigerant for low-temperature magnetic refrigeration.

Keywords: manganite perovskite, magnetocaloric effect, X-ray diffraction, relative cooling power

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Authors: Fouzia Amireche-Ziar, Ilham Mokbel, Jacques Jose

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The vapour pressures of the three binary mixtures: 1, 2- dichloroethane + 1,3-dioxolane, + 1,4-dioxane or + tetrahydropyrane, are carried out at ten temperatures ranging from 273 to 353.15 K. An accurate static device was employed for these measurements. The VLE data were reduced using the Redlich-Kister equation by taking into consideration the vapour pressure non-ideality in terms of the second molar virial coefficient. The experimental data were compared to the results predicted with the DISQUAC and Dortmund UNIFAC group contribution models for the total pressures P and the excess molar Gibbs energies GE.

Keywords: disquac model, dortmund UNIFAC model, excess molar Gibbs energies GE, VLE

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Authors: R. Sadeghzadegan, S. A. Naeini, A. Mirzaii

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In this article, the results of a series of carefully conducted laboratory test program were represented to determine the small strain shear modulus of sand mixed with a range of kaolinite including zero to 30%. This was experimentally achieved using a triaxial cell equipped with bender element. Results indicate that small shear modulus tends to increase, while clay content decreases and effective confining pressure increases. The exponent of stress in the power model regression analysis was not sensitive to the amount of clay content for all sand clay mixtures, while coefficient A was directly affected by change in clay content.

Keywords: small shear modulus, bender element test, plastic fines, sand

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Authors: Nanditha Rajamani, Anirudhaa R. Rao, Divya Sriram

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One of the greatest difficulties in treating patients with pain is the highly subjective nature of pain sensation. The measurement of pain intensity is primarily dependent on the patient’s report, often with little physical evidence to provide objective corroboration. This is also complicated by the fact that there are only few and expensive existing technologies (Functional Magnetic Resonance Imaging-fMRI). The need is thus clear and urgent for a reliable, non-invasive, non-painful, objective, readily adoptable, and coefficient diagnostic platform that provides additional diagnostic information to supplement its current regime with more information to assist doctors in diagnosing these patients. Thus, our idea of developing a pain detector was conceived to take a step further the detection and diagnosis of chronic and acute pain.

Keywords: pain sensor, microwave radiometery, pain sensation, fMRI

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Authors: Amir Mahyar Khorasani, Ian Gibson, Moshe Goldberg, Mohammad Masoud Movahedi, Guy Littlefair

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One of the important factors in manufacturing processes especially machining operations is surface quality. Improving this parameter results in improving fatigue strength, corrosion resistance, creep life and surface friction. The reliability and clearance of removable joints such as thread and nuts are highly related to the surface roughness. In this work, the effect of different cutting parameters such as cutting fluid pressure, feed rate and cutting speed on the surface quality of the crest of thread in the high-speed milling of Brass C3600 have been determined. Two popular neural networks containing MLP and RBF coupling with Taguchi L32 have been used to model surface roughness which was shown to be highly adept for such tasks. The contribution of this work is modelling surface roughness on the crest of the thread by using precise profilometer with nanoscale resolution. Experimental tests have been carried out for validation and approved suitable accuracy of the proposed model. Also analysing the interaction of parameters two by two showed that the most effective cutting parameter on the surface value is feed rate followed by cutting speed and cutting fluid pressure.

Keywords: artificial neural networks, cutting conditions, high-speed machining, surface roughness, thread milling

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Authors: Soon-Gil Yoon, Min-Ju Choi, Sung-Ho Shin, Junghyo Nah, Jin-Seok Choi, Hyun-A Song, Goeun Choi, Jin-Ho Choy

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Layered double hydroxides (LDHs) with positively charged brucite-like layers and negatively charged interlayer anions are considered a critical nanoscale building block with potential for application in catalysts, biological sensors, and optical, electrical, and magnetic devices. LDHs also have a great potential as an energy conversion device, a key component in common modern electronics. Although LDHs are theoretically predicted to be centrosymmetric, we report here the first observations of the flexoelectric nature of LDHs and demonstrate their potential as an effective energy conversion material. We clearly show a linear energy conversion relationship between the output powers and curvature radius via bending with both the LDH nanosheets and thin films, revealing a direct evidence for flexoelectric effects. These findings potentially open up avenues to incorporate a flexoelectric coupling phenomenon into centrosymmetric materials such as LDHs and to harvest high-power energy using LDH nanosheets. In the present study, for enhancement of the output power, Zn-Al:LDH nanosheets were composited with piezoelectric CH3NH3PbI3 (MAPbI3) dye films and their enhanced energy harvesting was demonstrated in detail.

Keywords: layered double hydroxides, flexoelectric, piezoelectric, energy harvesting

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Authors: A. V. Shelke, P. S. More

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This research aimed to study the kinetic reaction of reused cooking oil and to find the optimum condition of its process. The feedstock was collected from the street sellers and also prepared at laboratory. From this research, it is found that the kinetic reaction of reused sunflower oil (auto-oxidation) is obtained in terms of variation of the absorption coefficient of unexposed sunflower oil as 0.05 which is very close to that of exposed sunflower oil 0.075. At room temperature, the optimum intensity obtained from optical absorption spectroscopy study is 0.267 for unexposed sunflower oil and 0.194 for exposed sunflower oil. However, results indicated that FTIR spectroscopy is accurate and precise enough for such determination. Free Fatty Acid (FFA% = 026), acid ~53% and safonication ~%192 get reduce in exposed oil was investigated.

Keywords: friction, oxidation, sunflower oil, vegetable oils

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Authors: Mihai I. Sturza, Laura T. Corredor, Kaustuv Manna, Gizem A. Cansever, Tushar Dey, Andrey Maljuk, Olga Kataeva, Sabine Wurmehl, Anja Wolter, Bernd Buchner

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Recently, the iridate double perovskite Sr₂YIrO₆ has attracted considerable attention due to the report of unexpected magnetism in this Ir⁵⁺ material, in which according to the Jeff model, a non-magnetic ground state is expected. Structural, magnetic and thermodynamic investigations of Sr₂YIrO₆ and Ba2YIrO6 single crystals, with emphasis on the temperature and magnetic field dependence of the specific heat will be presented. The single crystals were grown by using SrCl₂ and BaCl₂ as flux. Single-crystal X-ray diffraction measurements performed on several crystals from different preparation batches showed a high quality of the crystals, proven by the good internal consistency of the data collected using the full-sphere mode and an extremely low R factor. In agreement with the expected non-magnetic ground state of Ir⁵⁺ (5d4) in these iridates, no magnetic transition is observed down to 430 mK. Moreover, our results suggest that the low-temperature anomaly observed in the specific heat is not related to the onset of long-range magnetic order. Instead, it is identified as a Schottky anomaly caused by paramagnetic impurities present in the sample, of the order of

Keywords: double perovskites, iridates, self-flux grown synthesis, spin-orbit coupling

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Authors: Abhigna Bhatt, Arnab Banerjee

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A periodic system with only a single coupling degree of freedom is called a monocoupled system. Monocoupled systems with mechanisms like mass in the mass system generates effective negative mass, mass connected with rigid links generates inertial amplification, and spring-mass connected with a rigid link generateseffective negative stiffness. In this paper, the representative unit cell is introduced, considering all three mechanisms combined. Further, the dynamic stiffness matrix of the unit cell is constructed, and the dispersion relation is obtained by applying the Bloch theorem. The frequency response function is also calculated for the finite length of periodic unit cells. Moreover, the input displacement signal is given to the finite length of periodic structure and using inverse Fourier transform to visualize the wave propagation in the time domain. This visualization explains the sudden attenuation in metamaterial due to energy dissipation by an embedded resonator at the resonance frequency. The visualization created for wave propagation is found necessary to understand the insights of physics behind the attenuation characteristics of the system.

Keywords: mono coupled system, negative effective mass, negative effective stiffness, inertial amplifier, fourier transform

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Authors: Enayat Davoudi

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This paper is about the study of media literacy and its role in Iranian society. Determine the research hypothesis by the use of James Patter theory and us stratification and also culture theory. By the use of traversal method and by the aim of the survey on 375 students in Mahmoudabad which was selected randomly, the data was gathered and analyzed by SPSS software. Coefficient alpha for Crohn Bach is used in order to reach to the justifiability of indexes. The research findings show that the variable like duration, rate and type of media use, the realization of media content, audience goal and motivation, economical and social base and the rate of education has a meaningful relation with media literacy.

Keywords: media, media literacy, Iranian society, Mahmoudabad students

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Authors: Y. Yongli, M. H. Aissa

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The purpose of this paper aims for a geotechnical analysis based on experimental physical and mechanical characteristics of Miocene marl situated at Medea region in Algeria. More than 150 soil samples were taken in the investigation part of the North-South Highway which extends over than 53 km from Chiffa in the North to Berrouaghia in the South of Algeria. The analysis of data in terms of Atterberg limits, plasticity index, and clay content reflects an acceptable correlation justified by a high coefficient of regression which was compared with the previous works in the region. Finally, approximated equations that serve as a guideline for geotechnical design locally have been suggested.

Keywords: correlation, geotechnical properties, miocene marl, north-south highway

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Authors: Carla Caiazza, Valentina Preziosi, Giovanna Tomaiuolo, Denis O'Sullivan, Vincenzo Guida, Stefano Guido

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In the last decades, wormlike micellar solutions have been extensively used to tune the rheological behavior of home care and personal care products. This and other successful applications underlie the growing attention that both basic and applied research are devoting to these systems, and to their unique rheological and flow properties. One of the key research topics is the occurrence of flow instabilities at high shear rates (such as shear banding), with the possibility of appearance of flow induced structures. In this scenario, microfluidics is a powerful tool to get a deeper insight into the flow behavior of a wormlike micellar solution, as the high confinement of a microfluidic device facilitates the onset of the flow instabilities; furthermore, thanks to its small dimensions, it can be coupled with optical microscopy, allowing a direct visualization of flow structuring phenomena. Here, the flow of a widely used wormlike micellar solution through a glass capillary has been studied, by coupling the microfluidic device with μPIV techniques. The direct visualization of flow-induced structures and the flow visualization analysis highlight a relationship between solution structuring and the onset of discontinuities in the velocity profile.

Keywords: flow instabilities, flow-induced structures, μPIV, wormlike micelles

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Authors: Miao Yang

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PPCPs (pharmaceutical and personal care products) in water, as an environmental pollutant, becomes an issue of increasing concern. Therefore, the techniques for degradation of PPCPs has been a hotspot in water pollution control field. Since there are several disadvantages for common degradation techniques of PPCPs, such as low degradation efficiency for certain PPCPs (ibuprofen and Carbamazepine) this proposal will adopt a combined technique by using CDs (carbon nanodots)/C₃N₄ composite and ultrasonic irradiation to mitigate or overcome these shortages. There is a significant scientific problem that the mechanism including PPCPs, major reactants, and interfacial active sites is not clear yet in the study of PPCPs degradation. This work aims to solve this problem by using both theoretical and experimental methodologies. Firstly, optimized parameters will be obtained by evaluating the kinetics and oxidation efficiency under different conditions. The competition between H₂O₂ and PPCPs with HO• will be elucidated, after which the degradation mechanism of PPCPs by the synergy of CDs/C₃N₄ composite and ultrasonic irradiation will be proposed. Finally, a sonolysis-adsorption-catalysis coupling mechanism will be established which is the theoretical basis and technical support for developing new efficient degradation techniques for PPCPs in the future.

Keywords: carbon nanodots/C₃N₄, pharmaceutical and personal care products, ultrasonic irradiation, hydroxyl radical, heterogeneous catalysis

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Authors: Lee Derk Huan, Nur Irmawati

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This paper aims to investigate the heat transfer and fluid flow characteristics of nanofluids used in spray cooling systems. The effect of spray height, type of nanofluids and concentration of nanofluids are numerically investigated. Five different nanofluids such as AgH2O, Al2O3, CuO, SiO2 and TiO2 with volume fraction range of 0.5% to 2.5% are used. The results revealed that the heat transfer performance decreases as spray height increases. It is found that TiO2 has the highest transfer coefficient among other nanofluids. In dilute spray conditions, low concentration of nanofluids is observed to be more effective in heat removal in a spray cooling system.

Keywords: numerical investigation, spray cooling, heat transfer, nanofluids

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Authors: M. Ramesh, Manish K. Niranjan

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The electronic, structural and thermoelectric properties of Mg₂SiSn (110) surface are investigated within the framework of first principle density functional theory and semi classical Boltzmann approach. In particular, directional dependent thermoelectric properties such as electrical conductivity, thermal conductivity, Seebeck coefficient and figure of merit are explored. The (110)-oriented Mg₂SiSn surface exhibits narrow indirect band gap of ~0.17 eV. The thermoelectric properties are found to be significant along the y-axis at 300 K and along x-axis at 500 K. The figure of merit (ZT) for hole carrier concentration is found to be significantly large having magnitude 0.83 (along x-axis) at 500 K and 0.26 (y-axis) at 300 K. Our results suggest that Mg₂SiSn (110) surface is promising for various thermoelectric applications due to its overall good thermoelectric properties.

Keywords: thermoelectric, surface science, semiconducting silicide, first principles calculations

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Authors: Rachna, Uma Shanker

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Aromatic phenols, being priority pollutants, are found in various industrial effluents and seeking the attention of environmentalists worldwide, owing to their life-threatening effects. In the present study, the coupling of zinc oxide with Prussian blue was achieved involving co-precipitation synthesis process using Azadirachta indica plant extract. The fabricated nanocatalyst was employed for the sunlight mediated photodegradation of various phenols (Phenol, 3-Aminophenol, and 2,4-Dinitrophenol). Doping of zinc oxide with Prussian blue caused an increase in the surface area to value 80.109 m²g⁻¹ and also enhanced the semiconducting tendency of the nanocomposite with band gap energy 1.101 eV. The experiment was performed at different parameters of phenols concentration, catalyst amount, pH, time, and exposure of sunlight. The obtained results showed a lower elimination of 2,4-DNP (93%) than 3-AP (97%) and phenol (95%) owing to their molecular weight and basicity differences. In comparison to the starting material (zinc oxide and Prussian blue), nanocomposite was more capable in degrading the phenols and lowered the t1/2 value of phenol (4.405 h), 3-AP (4.04 h) and 2,4-DNP (4.68 h) to a greater extent. Effect of different foreign anions was also studied to check nanocomposite’s liability under natural conditions. The extent of charge recombination being the most limiting factor in the photodegradation of pollutants was determined through the photoluminescence. Sunlight active ZnO@FeHCF nanocomposite was proven to exhibit good catalytic ability up to 10 cycles.

Keywords: nanocomposite, phenols, photodegradation, sunlight, water

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Authors: M. Helaimi, R. Taleb, D. Benyoucef, B. Belmadani

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This paper presents the design of a polynomial controller with coefficient diagram method (CDM). This controller is used to control the output power of high frequency resonant inverter with LLC tank. One of the most important problems associated with the proposed inverter is achieving ZVS operating during the induction heating process. To overcome this problem, asymmetrical voltage cancellation (AVC) control technique is proposed. The phased look loop (PLL) is used to track the natural frequency of the system. The small signal model of the system with the proposed control is obtained using extending describing function method (EDM). The validity of the proposed control is verified by simulation results.

Keywords: induction heating, AVC control, CDM, PLL, resonant inverter

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Authors: Chang He, Hiroshi Tamura, Hiroshi Katsuchi, Jiaqi Wang

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In this study, the aim is to infer the slip limit (static friction limit) of contact interfaces in bolt friction joints by analyzing other bolt friction joints with the same contact surface but in a different shape. By using the Weibull distribution to deal with microelements on the contact surface statistically, the slip limit of a certain type of bolt joint was predicted from other types of bolt joint with the same contact surface. As a result, this research succeeded in predicting the slip limit of bolt joins with different numbers of contact surfaces and with different numbers of bolt rows.

Keywords: bolt joints, slip coefficient, finite element method, Weibull distribution

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Authors: Ahmed Najah Ahmed Al-Mahfoodh, Ali Najah Ahmed Al-Mahfoodh, Ahmed Al-Shafie

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In this study, genetic programming (GP) technique has been investigated in prediction of set of rainfall-runoff data. To assess the effect of input parameters on the model, the sensitivity analysis was adopted. To evaluate the performance of the proposed model, three statistical indexes were used, namely; Correlation Coefficient (CC), Mean Square Error (MSE) and Correlation of Efficiency (CE). The principle aim of this study is to develop a computationally efficient and robust approach for predict of rainfall-runoff which could reduce the cost and labour for measuring these parameters. This research concentrates on the Johor River in Johor State, Malaysia.

Keywords: genetic programming, prediction, rainfall-runoff, Malaysia

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Authors: Ali Gul, Bhart Kumar, Samiullah Ansari

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The current research is focused on the study of various lengths of blades (i.e. 1 to 5m) and several bladed rotors (3,5,7 & 9) of small horizontal axis wind turbine under low wind conditions usingQBlade software. Initially, the rotor was designed using airfoil SG6043 with five different lengths of the blades. Subsequently, simulations were carried out in which, under low wind regimes, the power output was observed. Further, four rotors having 3,5,7 & 9 blades were analyzed. However, the most promising coefficient of performance (CP) was observed at the 3-bladed rotor. Both studies established a clear view of harvesting wind energy at low wind speeds that can be mobilized in the energy sector. That suggests the utilization of wind energy at the domestic levelwhich is acceleratory growing in the last few decades.

Keywords: small HAWT, QBlade, BEM, CFD

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Authors: H. Mohammadi Majd, M. Jalali Azizpour, V. Tavaf, A. Jaderi

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In upsetting processes contact friction significantly influence metal flow, stress-strain state and process parameters. Furthermore, tribological conditions influence workpiece deformation and its dimensional precision. A viscoplastic constitutive law, the Anand model, was applied to represent the inelastic deformation behavior in upsetting process. This paper presents research results of the influence of contact friction coefficient on a workpiece deformation in upsetting process.finite element parameters. This technique was tested for three different specimens simulations of the upsetting and the corresponding material and can be successfully employed to predict the deformation of the upsetting process.

Keywords: friction, upsetting, barreling, Anand model

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Authors: Rituparna Nath, Shawn J. Marshall

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Glaciers are one of the main sensitive climatic indicators, as they respond strongly to small climatic shifts. We develop a flow line model of glacier dynamics to simulate the past and future extent of glaciers in the Canadian Rocky Mountains, with the aim of coupling this model within larger scale regional climate models of glacier response to climate change. This paper will focus on glacier-climate modeling and reconstructions of glacier volume from the Little Ice Age (LIA) to present for Athabasca Glacier, Alberta, Canada. Glacier thickness, volume and mass change will be constructed using flow line modelling and examination of different climate scenarios that are able to give good reconstructions of LIA ice extent. With the availability of SPOT 5 imagery, Digital elevation models and GIS Arc Hydro tool, ice catchment properties-glacier width and LIA moraines have been extracted using automated procedures. Simulation of glacier mass change will inform estimates of meltwater run off over the historical period and model calibration from the LIA reconstruction will aid in future projections of the effects of climate change on glacier recession. Furthermore, the model developed will be effective for further future studies with ensembles of glaciers.

Keywords: flow line modeling, Athabasca Glacier, glacier mass balance, Remote Sensing, Arc hydro tool, little ice age

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Authors: Rafat Alshorman, Fadi Awawdeh

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By employing a simplified bilinear method, a class of generalized fifth-order KdV (gfKdV) equations which arise in nonlinear lattice, plasma physics and ocean dynamics are investigated. With the aid of symbolic computation, both solitary wave solutions and multiple-soliton solutions are obtained. These new exact solutions will extend previous results and help us explain the properties of nonlinear solitary waves in many physical models in shallow water. Parametric analysis is carried out in order to illustrate that the soliton amplitude, width and velocity are affected by the coefficient parameters in the equation.

Keywords: multiple soliton solutions, fifth-order evolution equations, Cole-Hopf transformation, Hirota bilinear method

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Authors: G .D. B. N. Kulasaooriya, H. B. S. Ariyarathne, I. Abeygunawardene, A. A. J. Rafarathne, B. V. Perera

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Elephant is the largest resident of the wild and has small surface to volume ratio as well as less number of sweat glands which cause challenges to the thermoregulation of this mammal. However, this megaherbivore has adopted specialised meachanisms to maintain its thermal balance through behavioral adaptations, ear flapping and well anastomosed arterioles and venules of the ear. Nevertheless, little is known on the involvement of the skin in the process of thermoregulation. The present study was undertaken to monitor the water evaporation rate from the skin of unrestrained wild elephant calves throughout the day and to understand its importance in the thermoregulation. Seven baby elephants housed in the elephant transit home, Udawalawe were used. Ambient temparature, relative humidity (RH) and radiation heat load was monitored throughout the day of the study period. Similarly, surface temparature of the skin was taken at six points including lateral ear pinna, lateral body and the rump during the same period. The skin water evaporation was also measured from the same sites using cobolt chloride method. The surface are of the skin was determined by assigning geometrical shapes to each body part. The results showed that the ambient temperature gradually increased with the day reaching maximum around 3.00 pm. The relative humidity was lowest early in the morning. The radiation heat load did not show any significant change in the study period. The skin temperature was different among lateral ear pinna, lateral body and the rump where the highest temperature was on the rump and the lowest on the lateral ear pinna. The skin temperature gradually increase with increasing ambient temperature but there was not a strong correlation (R2 =53.53) between these two. The skin temperature had strong correlation with RH (p<0.05 R2 =70.84% ) but a significant relationship was not considered since the radiation heat load was not varying in large scale. The skin evaporative water loss had a weak negative correlation with ambient temperature (correlation coefficient= -0.01) whereas strong positive correlation with RH (correlation coefficient= 25.275 ) and no corelation with radiation heat load. It also appeared that skin water loss increases as the skin temperature increased. In the present study, it was observed that on average, skin of the baby elephant looses 403 g/m2/h of water. Based on these observations it can be concluded that a large volume of water is evaporated from the skin of baby elephants and evaporative heat loss may be contributing significantly to the thermoregulation. However, further investigation on the influence of environmental factors on evaporative heat loss has to be conducted to understand the thermoregulatory mechanisms of the baby elephant.

Keywords: thermoregulation, behavioral adaptations, evaporation, elephant

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Authors: Muhammad Tariq A. Chaudhary

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Soil-structure interaction (SSI) in bridges under seismic excitation is a complex phenomenon which involves coupling between the non-linear behavior of bridge pier columns and SSI in the soil-foundation part. It is a common practice in the study of SSI to model the bridge piers as linear elastic while treating the soil and foundation with a non-linear or an equivalent linear modeling approach. Consequently, the contribution of soil and foundation to the SSI phenomenon is disproportionately highlighted. The present study considered non-linear behavior of bridge piers in FEM model of a 4-span, pile-supported bridge that was designed for five different soil conditions in a moderate seismic zone. The FEM model of the bridge system was subjected to a suite of 21 actual ground motions representative of three levels of earthquake hazard (i.e. Design Basis Earthquake, Functional Evaluation Earthquake and Maximum Considered Earthquake). Results of the FEM analysis were used to delineate the influence of pier column non-linearity and SSI on critical design parameters of the bridge system. It was found that pier column non-linearity influenced the bridge lateral displacement and base shear more than SSI for majority of the analysis cases for the class of bridge investigated in the study.

Keywords: bridge, FEM model, reinforced concrete pier, pile foundation, seismic loading, soil-structure interaction

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Authors: Bhagwant Singh, Sikander Singh Cheema

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This paper examines firewall mechanisms routinely implemented for network security in depth. A firewall can't protect you against all the hazards of unauthorized networks. Consequently, many kinds of infrastructure are employed to establish a secure network. Firewall strategies have already been the subject of significant analysis. This study's primary purpose is to avoid unnecessary connections by combining the capability of the firewall with the use of additional firewall mechanisms, which include packet filtering and NAT, VPNs, and backdoor solutions. There are insufficient studies on firewall potential and combined approaches, but there aren't many. The research team's goal is to build a safe network by integrating firewall strength and firewall methods. The study's findings indicate that the recommended concept can form a reliable network. This study examines the characteristics of network security and the primary danger, synthesizes existing domestic and foreign firewall technologies, and discusses the theories, benefits, and disadvantages of different firewalls. Through synthesis and comparison of various techniques, as well as an in-depth examination of the primary factors that affect firewall effectiveness, this study investigated firewall technology's current application in computer network security, then introduced a new technique named "tight coupling firewall." Eventually, the article discusses the current state of firewall technology as well as the direction in which it is developing.

Keywords: firewall strategies, firewall potential, packet filtering, NAT, VPN, proxy services, firewall techniques

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Authors: H. Aissa, L. Mouzai, M. Bouhadef

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The effects of down slope steepness on soil splash distribution under a water drop impact have been investigated in this study. The equipment used are the burette to simulate a water drop, a splash cup filled with sandy soil which forms the source area and a splash board to collect the ejected particles. The results found in this study have shown that the apparent mass increased with increasing downslope angle following a linear regression equation with high coefficient of determination. In the same way, the radial soil splash distribution over the distance has been analyzed statistically, and an exponential function was the best fit of the relationship for the different slope angles. The curves and the regressions equations validate the well known FSDF and extend the theory of Van Dijk.

Keywords: splash distribution, water drop, slope steepness, soil detachment

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Authors: Malo Pocheau-Lesteven, Olivier Le Maître

Abstract:

Engineering and optimisation of complex systems is often achieved through multi-disciplinary analysis of the system, where each subsystem is modeled and interacts with other subsystems to model the complete system. The coherence of the output of the different sub-systems is achieved through the use of compatibility constraints, which enforce the coupling between the different subsystems. Due to the complexity of some sub-systems and the computational cost of evaluating their respective models, it is often necessary to build surrogate models of these subsystems to allow repeated evaluation these subsystems at a relatively low computational cost. In this paper, gaussian processes are used, as their probabilistic nature is leveraged to evaluate the likelihood of satisfying the compatibility constraints. This paper presents infilling strategies to build accurate surrogate models of the subsystems in areas where they are likely to meet the compatibility constraint. It is shown that these infilling strategies can reduce the computational cost of building surrogate models for a given level of accuracy. An application of these methods to velocity prediction programs used in offshore racing naval architecture further demonstrates these method's applicability in a real engineering context. Also, some examples of the application of uncertainty quantification to field of naval architecture are presented.

Keywords: infilling strategy, gaussian process, multi disciplinary analysis, velocity prediction program

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