Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5597

Search results for: temperature

5357 Experimental Investigation of Cutting Forces and Temperature in Bone Drilling

Authors: Vishwanath Mali, Hemant Warhatkar, Raju Pawade

Abstract:

Drilling of bone has been always challenging for surgeons due to the adverse effect it may impart to bone tissues. Force has to be applied manually by the surgeon while performing conventional bone drilling which may lead to permanent death of bone tissues and nerves. During bone drilling the temperature of the bone tissues increases to higher values above 47 ⁰C that causes thermal osteonecrosis resulting into screw loosening and subsequent implant failures. An attempt has been made here to study the input drilling parameters and surgical drill bit geometry affecting bone health during bone drilling. A One Factor At a Time (OFAT) method is used to plan the experiments. Input drilling parameters studied include spindle speed and feed rate. The drill bit geometry parameter studied include point angle and helix angle. The output variables are drilling thrust force and bone temperature. The experiments were conducted on goat femur bone at room temperature 30 ⁰C. For measurement of thrust forces KISTLER cutting force dynamometer Type 9257BA was used. For continuous data acquisition of temperature NI LabVIEW software was used. Fixture was made on RPT machine for holding the bone specimen while performing drilling operation. Bone specimen were preserved in deep freezer (LABTOP make) under -40 ⁰C. In case of drilling parameters, it is observed that at constant feed rate when spindle speed increases, thrust force as well as temperature decreases and at constant spindle speed when feed rate increases thrust force as well as temperature increases. The effect of drill bit geometry shows that at constant helix angle when point angle increases thrust force as well as temperature increases and at constant point angle when helix angle increase thrust force as well as temperature decreases. Hence it is concluded that as the thrust force increases temperature increases. In case of drilling parameter, the lowest thrust force and temperature i.e. 35.55 N and 36.04 ⁰C respectively were recorded at spindle speed 2000 rpm and feed rate 0.04 mm/rev. In case of drill bit geometry parameter, the lowest thrust force and temperature i.e. 40.81 N and 34 ⁰C respectively were recorded at point angle 70⁰ and helix angle 25⁰ Hence to avoid thermal necrosis of bone it is recommended to use higher spindle speed, lower feed rate, low point angle and high helix angle. The hard nature of cortical bone contributes to a greater rise in temperature whereas a considerable drop in temperature is observed during cancellous bone drilling.

Keywords: bone drilling, helix angle, point angle, thrust force, temperature, thermal necrosis

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5356 The Effects of Displacer-Cylinder-Wall Conditions on the Performance of a Medium-Temperature-Differential γ-Type Stirling Engine

Authors: Wen-Lih Chen, Chao-Kuang Chen, Mao-Ju Fang, Hsiang-Cheng Hsu

Abstract:

In this study, we conducted CFD simulation to study the gas cycle of a medium-temperature-differential (MTD) γ-type Stirling engine. Mesh compression and expansion as well as overset mesh techniques are employed to simulate the moving parts of the engine. Shear-Stress Transport (SST) k-ω turbulence model has been adopted because the model is not prone to generate excessive turbulence upon impingement regions. Hence, wall heat transfer rates at the hot and cold ends will not be overestimated. The effects of several different displacer-cylinder-wall temperature setups, including smooth and finned walls, on engine performance are investigated. The results include temperature contours, pressure versus volume diagrams, and variations of heat transfer rates, indicated power, and efficiency. It is found that displacer-wall heat transfer is one of the most important factors on engine performance, and some wall-temperature setups produce better results than others.

Keywords: CFD, finned wall, MTD Stirling engine, heat transfer

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5355 A Study on Temperature and Drawing Speed for Diffusion Bonding Enhancement in Drawing of Hot Lined Pipes by FEM Analysis

Authors: M. T. Ahn, J. H. Park, S. H. Park, S. H. Ha

Abstract:

Diffusion bonding has been continuously studied. Temperature and pressure are the most important factors to increase the strength between diffusion bonded interfaces. Diffusion bonding is an important factor affecting the bonding strength of the lined pipe. The increase of the diffusion bonding force results in a high formability clad pipe. However, in the case of drawing, it is difficult to obtain a high pressure between materials due to a relatively small reduction in cross-section, and it is difficult to prevent elongation or to tear of material in hot drawing even if the reduction in the section is increased. In this paper, to increase the diffusion bonding force, we derive optimal temperature and pressure to suppress material stretching and realize precise thickness precision.

Keywords: diffusion bonding, temperature, pressure, drawing speed

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5354 Experimental Study on the Effect of Storage Conditions on Thermal Hazard of Nitrocellulose

Authors: Hua Chai, Qiangling Duan, Huiqi Cao, Mi Li, Jinhua Sun

Abstract:

Nitrocellulose (NC), a kind of energetic material, has been widely used in the industrial and military fields. However, this material can also cause serious social disasters due to storage conditions. Thermal hazard of nitrocellulose (NC) was experimentally investigated using the CALVET heat flux calorimeter C80, and three kinds of storage conditions were considered in the experiments: (1) drying time, (2) moisture content, (3) cycles. The results showed that the heat flow curves of NC moved to the low-temperature direction firstly and then slightly moved back by increasing the drying hours. Moisture that was responsible for the appearance of small exothermic peaks was proven to be the unfavorable safety factor yet it could increase the onset temperature of the main peak to some extent. And cycles could both lower the onset temperature and the maximum heat flow but enlarged the peak temperature. Besides, relevant kinetic parameters such as the heat of reaction (ΔH) and the activation energy (Ea) were obtained and compared. It was found that all the three conditions could reduce the values of Ea and most of them produced larger reaction heat. In addition, the critical explosion temperature (Tb) of the NC samples were derived. It was clear that not only the drying time but also the cycles would increase the thermal hazard of the NC. Yet, the right amount of water helped to reduce the thermal hazard.

Keywords: C80, nitrocellulose, storage conditions, the critical explosion temperature, thermal hazard

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5353 Effect of Temperature Condition in Extracting Carbon Fibers on Mechanical Properties of Injection Molded Polypropylene Reinforced by Recycled Carbon Fibers

Authors: Shota Nagata, Kazuya Okubo, Toru Fujii

Abstract:

The purpose of this study is to investigate the proper condition in extracting carbon fibers as the reinforcement of composite molded by injection method. Recycled carbon fibers were extracted from wasted CFRP by pyrolyzing epoxy matrix of CFRP under air atmosphere at different temperature conditions 400, 600 and 800°C in this study. Recycled carbon fiber reinforced polypropylene (RCF/PP) pellets were prepared using twin screw extruder. The RCF/PP specimens were molded into dumbbell shaped specimens using injection molding machine. The tensile strength of recycled carbon fiber was decreased with rising pyrolysis temperature from 400 to 800°C. However, superior mechanical properties of tensile strength, tensile modulus and fracture strain of RCF/PP specimen were obtained when the extracting temperature was 600°C. Almost fibers in RCF/PP specimens were aligned in the mold filling direction in this study when the extracting temperature was 600°C. To discuss the results, the failure mechanisms of RCF/PP specimens was shown schematically. Finally, it was concluded that the temperature condition at 600°C should be selected in extracting carbon fibers as the reinforcement of RCF/PP composite molded by injection method.

Keywords: CFRP, recycled carbon fiber, injection molding, mechanical properties, fiber orientation, failure mechanism

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5352 Reactivity Study on South African Calcium Based Material Using a pH-Stat and Citric Acid: A Statistical Approach

Authors: Hilary Rutto, Mbali Chiliza, Tumisang Seodigeng

Abstract:

The study on reactivity of calcined calcium-based material is very important in dry flue gas desulphurisation (FGD) process, so as to produce absorbent with high sulphur dioxide capture capacity during the hydration process. The effect of calcining temperature and time on the reactivity of calcined limestone material were investigated. In this study, the reactivity was measured using a pH stat apparatus and also confirming the result by performing citric acid reactivity test. The reactivity was calculated using the shrinking core model. Based on the experiments, a mathematical model is developed to correlate the effect of time and temperature to the reactivity of absorbent. The calcination process variables were temperature (700 -1000°C) and time (1-6 hrs). It was found that reactivity increases with an increase in time and temperature.

Keywords: reactivity, citric acid, calcination, time

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5351 A Comparative Study of a Defective Superconductor/ Semiconductor-Dielectric Photonic Crystal

Authors: S. Sadegzadeh, A. Mousavi

Abstract:

Temperature-dependent tunable photonic crystals have attracted widespread interest in recent years. In this research, transmission characteristics of a one-dimensional photonic crystal structure with a single defect have been studied. Here, we assume two different defect layers: InSb as a semiconducting layer and HgBa2Ca2Cu3O10 as a high-temperature superconducting layer. Both the defect layers have temperature-dependent refractive indexes. Two different types of dielectric materials (Si as a high-refractive index dielectric and MgF2 as a low-refractive index dielectric) are used to construct the asymmetric structures (Si/MgF2)NInSb(Si/MgF2)N named S.I, and (Si/MgF2)NHgBa2Ca2Cu3O10(Si/MgF2)N named S.II. It is found that in response to the temperature changes, transmission peaks within the photonic band gap of the S.II structure, in contrast to S.I, show a small wavelength shift. Furthermore, the results show that under the same conditions, S.I structure generates an extra defect mode in the transmission spectra. Besides high efficiency transmission property of S.II structure, it can be concluded that the semiconductor-dielectric photonic crystals are more sensitive to temperature variation than superconductor types.

Keywords: defect modes, photonic crystals, semiconductor, superconductor, transmission

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5350 The Effect of Cinnamaldehyde on Escherichia coli Survival during Low Temperature Long Time Cooking

Authors: Fuji Astuti, Helen Onyeaka

Abstract:

The aim of the study was to investigate the combine effects of cinnamaldehyde (0.25 and 0.45% v/v) on thermal resistance of pathogenic Escherichia coli during low temperature long time (LT-LT) cooking below 60℃. Three different static temperatures (48, 53 and 50℃) were performed, and the number of viable cells was studied. The starting concentrations of cells were 10⁸ CFU/ml. In this experiment, heat treatment efficiency for safe reduction indicated by decimal logarithm reduction of viable recovered cells, which was monitored for heating over 6 hours. Thermal inactivation was measured by means of establishing the death curves between the mean log surviving cells (log₁₀ CFU/ml) and designated time points (minutes) for each temperature test. The findings depicted that addition of cinnamaldehyde exhibited to elevate the thermal sensitivity of E. coli. However, the injured cells found to be well-adapted to all temperature tests after certain time point of cooking, in which they grew to more than 10⁵ CFU/ml.

Keywords: cinnamaldehyde, decimal logarithm reduction, Escherichia coli, LT-LT cooking

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5349 A Prospective Evaluation of Thermal Radiation Effects on Magneto-Hydrodynamic Transport of a Nanofluid Traversing a Spongy Medium

Authors: Azad Hussain, Shoaib Ali, M. Y. Malik, Saba Nazir, Sarmad Jamal

Abstract:

This article reports a fundamental numerical investigation to analyze the impact of thermal radiations on MHD flow of differential type nanofluid past a porous plate. Here, viscosity is taken as function of temperature. Energy equation is deliberated in the existence of viscous dissipation. The mathematical terminologies of nano concentration, velocity and temperature are first cast into dimensionless expressions via suitable conversions and then solved by using Shooting technique to obtain the numerical solutions. Graphs has been plotted to check the convergence of constructed solutions. At the end, the influence of effective parameters on nanoparticle concentration, velocity and temperature fields are also deliberated in a comprehensive way. Moreover, the physical measures of engineering importance such as the Sherwood number, Skin friction and Nusselt number are also calculated. It is perceived that the thermal radiation enhances the temperature for both Vogel's and Reynolds' models but the normal stress parameter causes a reduction in temperature profile.

Keywords: MHD flow, differential type nanofluid, Porous medium, variable viscosity, thermal radiation

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5348 Calibrations and Effect of Different Operating Conditions on the Performance of a Fluid Power Control System with Servo Solenoid Valve

Authors: Tahany W. Sadak, Fouly, A. Anwer, M. Rizk

Abstract:

The current investigation presents a study on the hydraulic performance of an electro-hydraulic servo solenoid valve controlled linear piston used in hydraulic systems. Advanced methods have been used to measure and record laboratory experiments, to ensure accurate analysis and evaluation. Experiments have been conducted under different values of temperature (28, 40 and 50 °C), supply pressure (10, 20, 30, 40 and 50 bar), system stiffness (32 N/mm), and load (0.0 & 5560 N). It is concluded that increasing temperature of hydraulic oil increases the quantity of flow rate, so it achieves an increase of the quantity of flow by 5.75 % up to 48.8 % depending on operating conditions. The values of pressure decay at low temperature are less than the values at high temperature. The frequency increases with the increase of the temperature. When we connect the springs to the system, it decreases system frequency. These results are very useful in the process of packing and manufacturing of fluid products, where the properties are not affected by 50 °C, so energy and time are saved.

Keywords: electro-hydraulic servo valve, fluid power control system, system stiffness, static and dynamic performance

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5347 Effects of Temperature Dryer on Allicin and Pirvic Acid Measurments Garlic Powder after Drying Process

Authors: Rezvani Aghdam Ali, Aleemrani Nejad Seyed Mohammad Hossein

Abstract:

Introduction: Dryed Garlic has plentiful health and medicinal value and is used in industrial food the forms of flakes or powders. Many health and medicinal properties of Garlic are attributed to allicin. This substance is produced enzymatically after crushing. Since temperature affected on enzymatic action, then is important factor on pirovic acid and allicin retention. Materials and Methods: This study investigated the effects of temperature on qualitative characteristics such as color of powder and pirovic acid and alicin retention in a convective hot-air dryer. For this reason, half cloves of Shushtar Garlics (Allium sativum L.) were dried at air temperatures of 50 and 70°C. Results: Results showed that increasing temperature was resulted changing color. Pirovic acid increased when half cloves Garlic were dried at 70°C. Allicin of half cloves also increased with increasing temperature. Conclusions: According to findings of this research, half cloves which dried in 70 degree centigrade can be introduced the best conditions for producing Garlic powder.

Keywords: garlic, drying, pirovic acid, allicin

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5346 Study of the Process of Climate Change According to Data Simulation Using LARS-WG Software during 2010-2030: Case Study of Semnan Province

Authors: Leila Rashidian

Abstract:

Temperature rise on Earth has had harmful effects on the Earth's surface and has led to change in precipitation patterns all around the world. The present research was aimed to study the process of climate change according to the data simulation in future and compare these parameters with current situation in the studied stations in Semnan province including Garmsar, Shahrood and Semnan. In this regard, LARS-WG software, HADCM3 model and A2 scenario were used for the 2010-2030 period. In this model, climatic parameters such as maximum and minimum temperature, precipitation and radiation were used daily. The obtained results indicated that there will be a 4.4% increase in precipitation in Semnan province compared with the observed data, and in general, there will be a 1.9% increase in temperature. This temperature rise has significant impact on precipitation patterns. Most of precipitation will be raining (torrential rains in some cases). According to the results, from west to east, the country will experience more temperature rise and will be warmer.

Keywords: climate change, Semnan province, Lars.WG model, climate parameters, HADCM₃ model

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5345 Thermal Analysis of a Graphite Calorimeter for the Measurement of Absorbed Dose for Therapeutic X-Ray Beam

Authors: I.J. Kim, B.C. Kim, J.H. Kim, C.-Y. Yi

Abstract:

Heat transfer in a graphite calorimeter is analyzed by using the finite elements method. The calorimeter is modeled in 3D geometry. Quasi-adiabatic mode operation is realized in the simulation and the temperature rise by different sources of the ionizing radiation and electric heaters is compared, directly. The temperature distribution caused by the electric power was much different from that by the ionizing radiation because of its point-like localized heating. However, the temperature rise which was finally read by sensing thermistors agreed well to each other within 0.02 %.

Keywords: graphite calorimeter, finite element analysis, heat transfer, quasi-adiabatic mode

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5344 Formation of Protective Silicide-Aluminide Coating on Gamma-TiAl Advanced Material

Authors: S. Nouri

Abstract:

In this study, the Si-aluminide coating was prepared on gamma-TiAl [Ti-45Al-2Nb-2Mn-1B (at. %)] via liquid-phase slurry procedure. The high temperature oxidation resistance of this diffusion coating was evaluated at 1100 °C for 400 hours. The results of the isothermal oxidation showed that the formation of Si-aluminide coating can remarkably improve the high temperature oxidation of bare gamma-TiAl alloy. The identification of oxide scale microstructure showed that the formation of protective Al2O3+SiO2 mixed oxide scale along with a continuous, compact and uniform layer of Ti5Si3 beneath the surface oxide scale can act as an oxygen diffusion barrier during the high temperature oxidation. The other possible mechanisms related to the formation of Si-aluminide coating and oxide scales were also discussed.

Keywords: Gamma-TiAl alloy, high temperature oxidation, Si-aluminide coating, slurry procedure

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5343 Thermal Analysis of Friction Stir Welded Dissimilar Materials with Different Preheating Conditions

Authors: Dr Prashant S Humnabad

Abstract:

The objective of this work is to carry out a thermal heat transfer analysis to obtain the time dependent temperature field in welding process friction stir welded dissimilar materials with different preheating temperature. A series of joints were made on four mm thick aluminum and steel plates. The temperature used was 100ºC, 150ºC and 200ºC. The welding operation was performed with different rotational speeds and traverse speed (1000, 1400 and 2000 rmp and 16, 20 and 25 mm/min..). In numerical model, the welded plate was modeled as the weld line is the symmetric line. The work-piece has dimensions of 100x100x4 mm. The obtained result was compared with experimental result, which shows good agreement and within the acceptable limit. The peak temperature at the weld zone increases significantly with respect to increase in process time.

Keywords: FEA, thermal analysis, preheating, friction stir welding

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5342 A Three-Dimensional TLM Simulation Method for Thermal Effect in PV-Solar Cells

Authors: R. Hocine, A. Boudjemai, A. Amrani, K. Belkacemi

Abstract:

Temperature rising is a negative factor in almost all systems. It could cause by self heating or ambient temperature. In solar photovoltaic cells this temperature rising affects on the behavior of cells. The ability of a PV module to withstand the effects of periodic hot-spot heating that occurs when cells are operated under reverse biased conditions is closely related to the properties of the cell semi-conductor material. In addition, the thermal effect also influences the estimation of the maximum power point (MPP) and electrical parameters for the PV modules, such as maximum output power, maximum conversion efficiency, internal efficiency, reliability, and lifetime. The cells junction temperature is a critical parameter that significantly affects the electrical characteristics of PV modules. For practical applications of PV modules, it is very important to accurately estimate the junction temperature of PV modules and analyze the thermal characteristics of the PV modules. Once the temperature variation is taken into account, we can then acquire a more accurate MPP for the PV modules, and the maximum utilization efficiency of the PV modules can also be further achieved. In this paper, the three-Dimensional Transmission Line Matrix (3D-TLM) method was used to map the surface temperature distribution of solar cells while in the reverse bias mode. It was observed that some cells exhibited an inhomogeneity of the surface temperature resulting in localized heating (hot-spot). This hot-spot heating causes irreversible destruction of the solar cell structure. Hot spots can have a deleterious impact on the total solar modules if individual solar cells are heated. So, the results show clearly that the solar cells are capable of self-generating considerable amounts of heat that should be dissipated very quickly to increase PV module's lifetime.

Keywords: thermal effect, conduction, heat dissipation, thermal conductivity, solar cell, PV module, nodes, 3D-TLM

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5341 On Radially Symmetric Vibrations of Bi-Directional Functionally Graded Circular Plates on the Basis of Mindlin’s Theory and Neutral Axis

Authors: Rahul Saini, Roshan Lal

Abstract:

The present paper deals with the free axisymmetric vibrations of bi-directional functionally graded circular plates using Mindlin’s plate theory and physical neutral surface. The temperature-dependent, as well as temperature-independent mechanical properties of the plate material, varies in radial and transverse directions. Also, temperature profile for one- and two-dimensional temperature variations has been obtained from the heat conduction equation. A simple computational formulation for the governing differential equation of motion for such a plate model has been derived using Hamilton's principle for the clamped and simply supported plates at the periphery. Employing the generalized differential quadrature method, the corresponding frequency equations have been obtained and solved numerically to retain their lowest three roots as the natural frequencies for the first three modes. The effect of various other parameters such as temperature profile, functionally graded indices, and boundary conditions on the vibration characteristics has been presented. In order to validate the accuracy and efficiency of the method, the results have been compared with those available in the literature.

Keywords: bi-directionally FG, GDQM, Mindlin’s circular plate, neutral axis, vibrations

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5340 Determination of Strain Rate Sensitivity (SRS) for Grain Size Variants on Nanocrystalline Materials Produced by ARB and ECAP

Authors: P. B. Sob, T. B. Tengen, A. A. Alugongo

Abstract:

Mechanical behavior of 6082T6 aluminum is investigated at different temperatures. The strain rate sensitivity is investigated at different temperatures on the grain size variants. The sensitivity of the measured grain size variants on 3-D grain is discussed. It is shown that the strain rate sensitivities are negative for the grain size variants during the deformation of nanostructured materials. It is also observed that the strain rate sensitivities vary in different ways with the equivalent radius, semi minor axis radius, semi major axis radius and major axis radius. From the obtained results, it is shown that the variation of strain rate sensitivity with temperature suggests that the strain rate sensitivity at the low and the high temperature ends of the 6082T6 aluminum range is different. The obtained results revealed transition at different temperature from negative strain rate sensitivity as temperature increased on the grain size variants.

Keywords: nanostructured materials, grain size variants, temperature, yield stress, strain rate sensitivity

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5339 Inorganic Microporous Membranes Fabricated by Atmospheric Pressure Plasma Liquid Deposition

Authors: Damian A. Mooney, Michael T. P. Mc Cann, J. M. Don MacElroy, Olli Antson, Denis P. Dowling

Abstract:

Atmospheric pressure plasma liquid deposition (APPLD) is a novel technology used for the deposition of thin films via the injection of a reactive liquid precursor into a high-energy discharge plasma at ambient pressure. In this work, APPLD, utilising a TEOS precursor, was employed to produce asymmetric membranes consisting of a thin (100 nm) layer of deposited silica on a microporous silica support in order to assess their suitability for high temperature gas separation applications. He and N₂ gas permeability measurements were made for each of the fabricated membranes and a maximum ideal He/N₂ selectivity of 66 was observed at room temperature. He, N₂ and CO2 gas permeances were also measured at the elevated temperature of 673K and ideal He/N₂ and CO₂/N₂ selectivities of 300 and 7.4, respectively, were observed. The results suggest that this plasma-based deposition technique can be a viable method for the manufacture of membranes for the efficient separation of high temperature, post-combustion gases, including that of CO₂/N₂ where the constituent gases differ in size by fractions of an Ångstrom.

Keywords: asymmetric membrane, CO₂ separation, high temperature, plasma deposition, thin films

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5338 Effect of Preparation Temperature on Producing Graphene Oxide by Chemical Oxidation Approach

Authors: Rashad Al-Gaashani, Muataz A. Atieh

Abstract:

In this study, the effect of preparation temperature, namely room temperature (RT), 40, 60, and 85°C, on producing of high-quality graphene oxide (GO) has been investigated. GO samples have been prepared by chemical oxidation of graphite via a safe improved chemical technique using a blend of two deferent acids: sulphuric acid (H₂SO₄) and phosphoric acid (H₃PO₄) with volume ratio 4:1, respectively. potassium permanganate (KMnO₄) and hydrogen peroxide (H₂O₂) were applied as oxidizing agents. In this work, sodium nitrate (NaNO₃) was excluded, so the emission of hazardous explosive gases such as NO₂ and N₂O₂ was shunned. Ice and oil baths were used to carefully control the temperature. Several characterization instruments including X-Ray diffraction, transmission electron microscopy, scanning electron microscopy, electron dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-vis spectroscopy were used to study and compare the synthesized samples. The results indicated that GO can be prepared at RT with graphite oxide, and the purity of GO increased with rising of the solvent temperature. Optical properties of GO samples were studied using UV-vis absorption spectra.

Keywords: chemical method, graphite, graphene oxide, optical properties

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5337 Investigation of Parameters Affecting Copper Recovery from Brass Melting Dross

Authors: Sercan Basit, Muhlis N. Sarıdede

Abstract:

Metal amounts of copper based compounds in the various wastes have been recovered successfully by hydrometallurgical treatment methods in the literature. X-ray diffraction pattern of the brass melting slag demonstrates that it contains sufficient amount of recoverable copper. Recovery of copper from brass melting dross by sulfuric acid leaching and the effect of temperature and acid and oxidant concentration on recovery rate of copper have been investigated in this study. Experiments were performed in a temperature-controlled reactor in sulfuric acid solution in different molarities using solid liquid ratio of 100 g/L, with leaching time of 300 min. Temperature was changed between 25 °C and 80 °C and molarity was between 0.5 and 3M. The results obtained showed that temperature has important positive effect on recovery whereas it decreases with time. Also copper was recovered in larger amounts from brass dross in the presence of H2O2 as an oxidant according to the case that oxidant was not used.

Keywords: brass dross, copper recovery, hydrogen peroxide, leaching

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5336 Numerical Analysis of Internal Cooled Turbine Blade Using Conjugate Heat Transfer

Authors: Bhavesh N. Bhatt, Zozimus D. Labana

Abstract:

This work is mainly focused on the analysis of heat transfer of blade by using internal cooling method. By using conjugate heat transfer technology we can effectively compute the cooling and heat transfer analysis of blade. Here blade temperature is limited by materials melting temperature. By using CFD code, we will analyze the blade cooling with the help of CHT method. There are two types of CHT methods. In the first method, we apply coupled CHT method in which all three domains modeled at once, and in the second method, we will first model external domain and then, internal domain of cooling channel. Ten circular cooling channels are used as a cooling method with different mass flow rate and temperature value. This numerical simulation is applied on NASA C3X turbine blade, and results are computed. Here results are showing good agreement with experimental results. Temperature and pressure are high at the leading edge of the blade on stagnation point due to its first faces the flow. On pressure side, shock wave is formed which also make a sudden change in HTC and other parameters. After applying internal cooling, we are succeeded in reducing the metal temperature of blade by some extends.

Keywords: gas turbine, conjugate heat transfer, NASA C3X Blade, circular film cooling channel

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5335 An Investigation of System and Operating Parameters on the Performance of Parabolic Trough Solar Collector for Power Generation

Authors: Umesh Kumar Sinha, Y. K. Nayak, N. Kumar, Swapnil Saurav, Monika Kashyap

Abstract:

The authors investigate the effect of system and operating parameters on the performance of high temperature solar concentrator for power generation. The effects of system and operating parameters were investigated using the developed mathematical expressions for collector efficiency, heat removal factor, fluid outlet temperature and power, etc. The results were simulated using C++program. The simulated results were plotted for investigation like effect of thermal loss parameter and radiative loss parameters on the collector efficiency, heat removal factor, fluid outlet temperature, rise of temperature and effect of mass flow rate of the fluid outlet temperature. In connection with the power generation, plots were drawn for the effect of (TM–TAMB) on the variation of concentration efficiency, concentrator irradiance on PM/PMN, evaporation temperature on thermal to electric power efficiency (Conversion efficiency) of the plant and overall efficiency of solar power plant.

Keywords: parabolic trough solar collector, radiative and thermal loss parameters, collector efficiency, heat removal factor, fluid outlet and inlet temperatures, rise of temperature, mass flow rate, conversion efficiency, concentrator irradiance

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5334 Experimental Research of Smoke Impact on the Performance of Cylindrical Eight Channel Cyclone

Authors: Pranas Baltrėnas, Dainius Paliulis

Abstract:

Cyclones are widely used for separating particles from gas in energy production objects. Efficiency of normal centrifugal air cleaning devices ranges from 85 to 90%, but weakness of many cyclones is low collection efficiency of particles less than 10 μm in diameter. Many factors have impact on cyclone efficiency – humidity, temperature, gas (air) composition, airflow velocity and etc. Many scientists evaluated only effect of origin and size of PM on cyclone efficiency. Effect of gas (air) composition and temperature on cyclone efficiency still demands contributions. Complex experimental research on efficiency of cylindrical eight-channel system with adjustable half-rings for removing fine dispersive particles (< 20 μm) was carried out. The impact of gaseous smoke components on removal of wood ashes was analyzed. Gaseous components, present in the smoke mixture, with the dynamic viscosity lower than that of same temperature air, decrease the d50 value, simultaneously increasing the overall particulate matter removal efficiency in the cyclone, i.e. this effect is attributed to CO2 and CO, while O2 and NO have the opposite effect. Air temperature influences the d50 value, an increase in air temperature yields an increase in d50 value, i.e. the overall particulate matter removal efficiency declines, the reason for this being an increasing dynamic air viscosity. At 120 °C temperature the d50 value is approximately 11.8 % higher than at air temperature of 20 °C. With an increase in smoke (gas) temperature from 20 °C to 50 °C, the aerodynamic resistance in a 1-tier eight-channel cylindrical cyclone drops from 1605 to 1380 Pa, from 1660 to 1420 Pa in a 2-tier eight-channel cylindrical cyclone, from 1715 to 1450 Pa in a 3-tier eight-channel cylindrical cyclone. The reason for a decline in aerodynamic resistance is the declining gas density. The aim of the paper is to analyze the impact of gaseous smoke components on the eight–channel cyclone with tangential inlet.

Keywords: cyclone, adjustable half-rings, particulate matter, efficiency, gaseous compounds, smoke

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5333 Thermal Analysis of a Composite of Coco Fiber and Látex

Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale

Abstract:

Given the unquestionable need of environmental preservation, the natural fibers have been seen as a salutary alternative for production of composites in substitution to the synthetic fibers, vitreous and metallic. In this work, the behavior of a composite was analyzed done with fiber of the peel of the coconut as reinforcement and latex as head office, when submitted the source of heat. The temperature profiles were verified in the internal surfaces and it expresses of the composite as well as the temperature gradient in the same. It was also analyzed the behavior of this composite when submitted to a cold source. As consequence, in function of the answers of the system, conclusions were reached.

Keywords: natural fiber, composite, temperature, latex, gradient

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5332 Computer Simulation of Hydrogen Superfluidity through Binary Mixing

Authors: Sea Hoon Lim

Abstract:

A superfluid is a fluid of bosons that flows without resistance. In order to be a superfluid, a substance’s particles must behave like bosons, yet remain mobile enough to be considered a superfluid. Bosons are low-temperature particles that can be in all energy states at the same time. If bosons were to be cooled down, then the particles will all try to be on the lowest energy state, which is called the Bose Einstein condensation. The temperature when bosons start to matter is when the temperature has reached its critical temperature. For example, when Helium reaches its critical temperature of 2.17K, the liquid density drops and becomes a superfluid with zero viscosity. However, most materials will solidify -and thus not remain fluids- at temperatures well above the temperature at which they would otherwise become a superfluid. Only a few substances currently known to man are capable of at once remaining a fluid and manifesting boson statistics. The most well-known of these is helium and its isotopes. Because hydrogen is lighter than helium, and thus expected to manifest Bose statistics at higher temperatures than helium, one might expect hydrogen to also be a superfluid. As of today, however, no one has yet been able to produce a bulk, hydrogen superfluid. The reason why hydrogen did not form a superfluid in the past is its intermolecular interactions. As a result, hydrogen molecules are much more likely to crystallize than their helium counterparts. The key to creating a hydrogen superfluid is therefore finding a way to reduce the effect of the interactions among hydrogen molecules, postponing the solidification to lower temperature. In this work, we attempt via computer simulation to produce bulk superfluid hydrogen through binary mixing. Binary mixture is a technique of mixing two pure substances in order to avoid crystallization and enhance super fluidity. Our mixture here is KALJ H2. We then sample the partition function using this Path Integral Monte Carlo (PIMC), which is well-suited for the equilibrium properties of low-temperature bosons and captures not only the statistics but also the dynamics of Hydrogen. Via this sampling, we will then produce a time evolution of the substance and see if it exhibits superfluid properties.

Keywords: superfluidity, hydrogen, binary mixture, physics

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5331 Effect of Annealing Temperature on the Photoelectric Work Function of Silver-Zinc Oxide Contact Materials

Authors: Bouchou Aïssa, Mohamed Akbi

Abstract:

Contact materials used for electrical breakers are often made with silver alloys. Mechanical and thermo dynamical properties as well as electron emission of such complicated alloys present a lack of reliable and accurate experimental data. This paper deals mainly with electron work function (EWF) measurements about silver-metal oxide (Ag-MeO) electrical contacts (Ag-ZnO (92/8), before and after surface heat treatments at 296 K  813 K, under UHV conditions (residual gas pressure of 1.4 x 10-7 mbar). The electron work function (EWF) of silver zinc oxide materials was measured photoelectrically, using both Fowler’s method of isothermal curves and linearized Fowler plots. In this paper, we present the development of a method for measuring photoelectric work function of contact materials. Also reported in this manuscript are the results of experimental work whose purpose has been the buildup of a reliable photoelectric system and associated monochromatic ultra-violet radiations source, and the photoelectric measurement of the electron work functions (EWF) of contact materials. In order to study the influence of annealing temperature on the EWF, a vacuum furnace was used for heating the metallic samples up to 800 K. The EWF of the silver – zinc oxide materials were investigated to study the influence of annealing temperature on the EWF. In the present study, the photoelectric measurements about Ag-ZnO(92/8) contacts have shown a linear decrease of the EWF with increasing temperature, i.e. the temperature coefficient is constant and negative: for the first annealing # 1, in the temperature range [299 K  823 K]. On the contrary, a linear increase was observed with increasing temperature (i.e. , being constant and positive), for the next annealing # 2, in the temperature range [296 K  813 K]. The EWFs obtained for silver-zinc oxide Ag-ZnO(92/8) show an obvious dependence on the annealing temperature which is strongly associated with the evolution of the arrangement on ZnO nano particles on the Ag-ZnO contact surface as well as surface charge distribution.

Keywords: Photoemission, Electron work function, Fowler methods, Ag-ZnO contact materials, Vacuum heat treatment

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5330 Study of Some Epidemiological Factors Influencing the Disease Incidence in Chickpea (Cicer Arietinum L.)

Authors: Muhammad Asim Nazir

Abstract:

The investigations reported in this manuscript were carried on the screening of one hundred and seventy-eight chickpea germplasm lines/cultivars against wilt disease, caused by Fusarium oxysporum f. sp. ciceris. The screening was conducted in vivo (field) conditions. The field screening was accompanied with the study of some epidemiological factors affecting the occurrence and severity of the disease. Among the epidemiological factors maximum temperature range (28-40°C), minimum temperature range (12-24°C), relative humidity (19-44%), soil temperature (26-41°C) and soil moisture range (19-34°C) was studied for affecting the disease incidence/severity. The results revealed that air temperature was positively correlated with diseases. Soil temperature data revealed that in all cultivars disease incidence was maximum as 39°C. Most of the plants show 40-50% disease incidence. Disease incidence decreased at 33.5°C. The result of correlation of relative humidity of air and wilt incidence revealed that all cultivars/lines were negatively correlated with relative humidity. With increasing relative humidity wilt incidence decreased and vice versa.

Keywords: chickpea, epidemiological, screening, disease

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5329 Effect of Annealing Temperature on Microstructural Evolution of Nanoindented Cu/Si Thin Films

Authors: Woei-Shyan Lee, Yu-Liang Chuang

Abstract:

The nano-mechanical properties of as-deposited Cu/Si thin films indented to a depth of 2000 nm are investigated using a nanoindentation technique. The nanoindented specimens are annealed at a temperature of either 160 °C or 210°C, respectively. The microstructures of the as-deposited and annealed samples are then examined via transmission electron microscopy (TEM). The results show that both the loading and the unloading regions of the load-displacement curve are smooth and continuous, which suggests that no debonding or cracking occurs during nanoindentation. In addition, the hardness and Young’s modulus of the Cu/Si thin films are found to vary with the nanoindentation depth, and have maximum values of 2.8 GPa and 143 GPa, respectively, at the maximum indentation depth of 2000 nm. The TEM observations show that the region of the Cu/Si film beneath the indenter undergoes a phase transformation during the indentation process. In the case of the as-deposited specimens, the indentation pressure induces a completely amorphous phase within the indentation zone. For the specimens annealed at a temperature of 160°C, the amorphous nature of the microstructure within the indented zone is maintained. However, for the specimens annealed at a higher temperature of 210°C, the indentation affected zone consists of a mixture of amorphous phase and nanocrystalline phase. Copper silicide (η-Cu3Si) precipitates are observed in all of the annealed specimens. The density of the η-Cu3Si precipitates is found to increase with an increasing annealing temperature.

Keywords: nanoindentation, Cu/Si thin films, microstructural evolution, annealing temperature

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5328 The Experimental Investigation of Temperature Influence on the Oscillations of Particles on Liquid Surfaces

Authors: Sathish K. Gurupatham, Farhad Sayedzada, Naji Dauk, Valmiki Sooklal, Laura Ruhala

Abstract:

It was shown recently that small particles and powders spontaneously disperse on liquid surfaces when they come into contact with the interface for the first time. This happens due to the combined effect of the capillary force, buoyant weight of the particle and the viscous drag that the particle experiences in the liquid. The particle undergoes oscillations normal to the interface before it comes to rest on the interface. These oscillations, in turn, induce a flow on the interface which disperses the particles radially outward. This phenomenon has a significant role in the pollination of sea plants such as Ruppia in which the formation of ‘pollen rafts’ is the first step. This paper investigates, experimentally, the influence of the temperature of the liquid on which this dispersion occurs. It was observed that the frequency of oscillations of the particles decreased with the increase in the temperature of the liquid. It is because the magnitude of capillary force also decreased when the temperature of the liquid increased.

Keywords: particle dispersion, capillary force, viscous drag, oscillations

Procedia PDF Downloads 183