bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Non-Conventional Aging Treatments on the Tensile Properties of Non-Hipped Castings of Aluminum Alloy 354
Authors: Babu G. Dinesh , Muktinutalapati Nageswara Rao
Published: February 2014

Cast aluminum alloy 354 is used extensively for production of critical automobile components, owing to its excellent castability and attractive combination of mechanical properties after heat-treatment. With the advent of higher performance engines, there has been a steady demand to further improve the mechanical behavior of the castings made of the alloy, among others, through improvements in processing. The present study explores the possibility of improving tensile properties of the alloy by adopting certain non-conventional aging treatments. The non-conventional treatments include aging cycles similar to T6I4 and T6I6 referred to in the published literature, artificial aging in two steps instead of in single step and artificial aging preceded by various natural aging times. The results show that none of these non-conventional treatments leads to improvement of all tensile properties compared to the standard T61 treatment. Significant hardening takes place in the alloy due to natural aging. Changing the time of natural aging preceding artificial aging was found to have little effect on tensile properties.
Study on Temperature Influence on Lack of Fusion Formation in Spatter/Base Metal Interface
Authors: Li Pei Gang , Svensson Lars Erik , Markocsan Nicolaie
Published: February 2014

In the development of modern welded structures with longer life-time and/or higher load-carrying ability, fatigue properties are becoming more and more important. A lot of researches have been done to investigate which factors can elongate the fatigue life of weldments. Cold lap defects, were found to be important initiation sites of the fatigue failure in 1990s. In the ISO standard, cold lap is referred to as a type of micro-lack of fusion. Previous study found that most of the cold laps in GMAW process are formed in spatters. In this paper the interface of spatter/base metal was cut, polished and investigated by conventional metallographic methods. The aim is to reveal the influence of temperature on cold lap formation. In the experiments, different pre-heating temperatures of the parent plate were used in tandem GMAW. Results showed linear empirical relationship between the temperature of the parent plate and the amount of lack of fusion in the spatter/base metal interface.
An Environmental Impact Comparison of Distributed and Centralized Manufacturing Scenarios
Authors: Senyana Lionel , Cormier Denis
Published: February 2014

Centralized manufacturing and distributed manufacturing are two fundamentally different methods for producing components. This work describes a centralized manufacturing scenario in which parts are produced via forging and finish machining at one central location and are then shipped to the end user. The distributed manufacturing model involves a scenario in which an additive manufacturing process (Electron Beam Melting) is used to produce parts to near net shape with minimal finish machining. Because the process doesn’t require molds or dies, production can take place in small production quantities “on demand” at job shops located close to the end user with little transportation. This is in stark contrast to the centralized model where large quantities of parts are produced and then distributed at a later date when needed from warehouses. The aim of this research is to compare the environmental impact of these two different production approaches under a variety of conditions. The SimaPro software has been used model both approaches with input from the user involving part size, amount of finish machining, transportation distances, mode of transportation, production quantities, etc.
Preparation and Properties of Rectorite/Epoxy Nanocomposites
Authors: Zeng Ting Ting , Chen Lai , Li Da Peng , Sun Jin Liang , Zhou Ze , Li Shi Xia
Published: February 2014

The Org-rectorite, which was used as a filler in the Rectorite/Epoxy nanocomposites, was prepared by the intercalation and exfoliation of rectorite with dodecyl-bis (2-hydroxyethyl)-methylazanium chloride as the organic cation exchange agent. The two curing agents methyl hexahydrophthalic anhydride (MHHPA) and m-phenylenediamine were employed at working temperature ranging from 70 °C to 190 °C. The samples were characterized by Fourier Transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) analysis. The results show that the d001 (55.9 Å) of Rectorite/Epoxy composites cured with MHHPA at 70 °C was larger than the Org-rectorite (28.7 Å), and the Org-rectorite was exfoliated at 90 °C working temperature. While the d001 of Rectorite/Epoxy composites cured with m-phenylenediamine at 70 °C and 90 °C were 40.9 Å and 42.1 Å , and were exfoliated at 140 °C. The apparent activation energy (Ea) of Rectorite/Epoxy composites cured with MHHPA and m-phenylenediamine were obtained to be 74.85 and 59.15 KJ/mol, respectively. The higher apparent activation energy (Ea) of MHHPA systems may be responsible for the lower exfoliation temperature.
Novel Anti-Caking Materials in Compound Fertiliezer Based on Waste Animal/Plant Oil
Authors: Hu Pan , Zhang Yi He , Zhou Feng Shan , Wang Yue , Fu Meng , Cui Bao Lin , Meng Xiang Hai
Published: February 2014

A novel anti-caking material (E-Oil) was prepared from waste animal/plant oil and triethanolamine by catalytic synthesis in this study. The E-Oil was analyzed by FTIR and the anti-caking effect of anti-caking materials was described by caking ratio. The FTIR results showed that the reaction product of Waste Animal/Plant Oil and Hydramine was surfactant with anti-caking effect. The anti-caking test results indicated that E-Oil made the caking ratio of compound fertilizer decrease from 39.75% to 16.33%. Taking the cost into consideration, the optimal fraction of E Oil was 5‰ and the caking ratio could reach 16.33%, which could approximately meet the application requirements.
The Synergistic Activity of the Extracts from Mango and Tamarind Gum in Cotton Fabric Finishing
Authors: Satirapipathkul Chutimon , Duangsri Pichet , Sittikijyothin Wancheng
Published: February 2014

This study focused on the development of antibacterial cotton fabric using natural bioactive agent as the extracts from mango (Mangifera indica L) seed. The cotton fabrics have been treated with the extracts from mango seed. Moreover, the tamarind gum from Tamarind indica seed was used as an alternative natural mordant and compared with general chemical mordants (alum and ferrous sulfate) in order to search for eco-friendly process. Treated fabrics were tested for antimicrobial activities against Gram-positive cocci and Gram-negative rods. We have found that in terms of antibacterial activity, the treated fabrics combined with natural mordant were more effective against both tested bacteria. From the results, the tamarind gum could provide the synergic antibacterial activity when applied with the extracts from mango seed and obviously used as substitutes for toxic textile chemicals.
Nanostructured Hydrogel Dressings on Base of Crosslinked Polyvinylpyrrolidone for Biomedical Application
Authors: Irmukhametova G.S. , Shaikhutdinov E.M. , Rakhmetullayeva R.K. , Yermukhambetova B.B. , Ishanova A.K. , Temirkhanova G. , Mun G.A.
Published: February 2014

Hydrogel dressings for biomedical application were obtained by γ-irradiation of poly-N-vinipirrolidon (PVP), agar-agar, polyethylene glycol and silver nitrate solution. Influence of irradiation doses (range from 25 kGy to 75 kGy), silver nitrate concentration and PVP concentration in initial monomer mixture on properties of obtained material were investigated. Presence and distribution of silver nanoparticles in obtained bandages is confirmed by optical microscopy and atomic force spectroscopy. Antimicrobial activity study in vitro showed antimicrobial activity, flexibility, high sorption capacity to water and biological fluids.
The Effect of Atmosphere and Vacuum on Character of Weld Joints Fabricated by Explosion
Authors: Jáňa Miroslav , Turňa Milan , Ondruška Jozef , Nesvadba Petr
Published: February 2014

This paper presents an experiment conducted in Explosia, a.s., Pardubice. A bimetal prepared of AZ 31 Mg alloy - CrNi austenitic steel was tested in various conditions, and consequently its quality was assessed. Focus was particularly on the impact of atmosphere and vacuum on the interface character of the metals (bimetals) prepared by explosion. Parallel placement of the materials being welded was used for welding in both vacuum and air atmosphere. Welding sets were designed and manufactured. The welding parameters and conditions were set up utilising the available computational means, and then verified by simulation in ANSYS engineering-scientific program. Used was Semtex S 35, a loose explosive, as well as Startline 12, an initiation explosive. Bimetal was fabricated in the air atmosphere at the detonation speed 2613 m.s-1 and in vacuum at the detonation speed 2597 m.s-1. Quality of bimetals was assessed by optical microscopy, measuring deformations by a 3D scanner, measuring microhardness and also by EDX microanalysis.
Investigations into the Growth of GaN Nanowires by MOCVD Using Azidotrimethylsilane as Nitrogen Source
Authors: Velazquez Miguel Angel Nuñez , Juárez-López Fernando
Published: February 2014

Gallium trichloride (GaCl3) and azidotrimethylsilane (CH3)3SiN3 were employed as alternatives gallium and nitrogen precursors respectively in the growth of GaN nanowires via a metal-organic chemical vapor deposition (MOCVD) system. Au pre-deposition on Si (100) substrate was using as catalysis seed to grown of GaN nanowires. X-Ray, FE-SEM and AFM analyses reveal that nanowires grown at temperature 1050 C present morphology characteristic to model VLS. Scanning electron microscopy reveal a surface morphology made up of wurzite that suggests that wires growth involve a melting process. A nucleation and growth mechanism, involving the congruent melting clusters of precursor molecules on the hot substrate surface, is therefore invoked to explain these observations. We attributed the improved growth behavior to the nearer-to-equilibrium growth and may be close to local thermodynamic equilibrium.
Natural Mineral for Improving Concrete Compressive Strength
Authors: Namdar Abdoullah , Zakaria Ideris Bin , Pelko Azam Khodashenas , Muhammad Nurmunira Binti
Published: February 2014

Several concrete additives have been innovated for improving concrete quality. In this research work the treated kaolin by heat has been used as concrete additive. Kaolin was subjected to the heat for 1 hour in different degree of temperatures. The crystal structure of Kaolin thermally is modified under heat and microstructure of the hydrated samples has been investigated using FESEM. The main objective is to introduce a cost effective concrete additive. The result is indicated that when kaolin subjected to 800 oC and used in 6% quantity as an additive in concrete mixed design, the concrete compressive strength of 14 days is 40% higher than concrete compressive strength of 28 days which is not used any additive. And if 12% additive is used the concrete compressive strength increased in same level on 7 days. This concrete additive reduces construction cost and time.
Resistance Spot Welding of Low Carbon Steel to Austenitic CrNi Stainless Steel
Authors: Kolařík Ladislav , Sahul Miroslav , Kolaříková Marie , Sahul Martin , Turňa Milan
Published: February 2014

The contribution deals with resistance spot welding of low carbon steel to austenitic CrNi stainless steel. The thickness of welded dissimilar steels was 2 mm. DeltaSpot welding gun with process tape was utilized for welding of the above-mentioned combination of steels. Resistance spot welds were produced under different welding currents. The welding currents used were 7 kA, 7.5 kA and 8 kA, respectively. Optical microscopy, microhardness measurement across the weld joint and EDX analysis across the weld joint interface were used to evaluate the quality of resistance spot welds of dissimilar steels.
Preparation and Characterization of Unsaturated Polyester/Organic Montmorillonite Nanocomposites
Authors: Tsai Tsung Yen , Chen Wen Chi , Zhou Guan Ren , Shiu Wei Chuan
Published: February 2014

This study uses in-situ polymerization method due to organic modified montmorillonite into unsaturated polyester to form a advanced montmorillonite / unsaturated polyester (MMT /UP) nanocomposites. Using of the blasting force generated in situ polymerization patterns show the formation of clay layers is exfoliation structure in polymer and improving of thermal properties, flame retardant properties, and mechanical properties.The d-spacing of organic modified clay could be determined whether the modifier was intercalated into the gallery of clay by applying the wide-angle X-ray diffraction (WXRD). The functional groups of modified clay were measured by Fourier infrared spectroscopy (FT-IR). The dispersion morphologies of MMT / UP nanocomposites were characterized by the wide-angle X-ray diffraction (WXRD) and transmission electron microscopy (TEM). The thermal properties and mechanical properties were investigated by thermal gravimetric analysis (TGA), limiting oxygen index meter (LOI), cone calorimeter (Heat Release Rate) and a dynamic mechanical analyzer (DMA).
Preparation and Performance of Bubble-Type Actuator for Braille Display
Authors: Kim Sungjin , Oh Jaeho , Lee Jihong , Yoo Yonghwan , Bismark Mensah , Nah Changwoon
Published: February 2014

Technology involved in braille display for blind or visually impaired people plays an important role as typical paper form of braille cannot be changed whereas display form of braille can be done at any time. Dielectric elastomers (DEs) are electroactive polymers with low elastic stiffness and elongation, with high dielectric constant have been found for actuator application. In the present study, we have used acrylic elastomer to manufacture a bubble-type actuator and its deformation was examined with increasing electrical field to find its suitability to use as a braille.
Compatibility Study of Replacement Material for Cold Cutting Machine
Authors: Aziz Mohamad Redhwan Abd. , Baba Nor Bahiyah , Shafee Mohd Lutfi Syahmi
Published: February 2014

This paper discussed the compatibility study on the possible materials to replace the existing material used in the cold cutting machine (CCM). The current CCM required a weight reduction and up to 33% was achieved. A reverse engineering process was carried out to investigate the structure and material used. The information gathered to be an input for materials analysis using a Cambridge Materials Selectors software. A comparison of possible replacement materials such as Aluminum Alloy, Carbon fiber reinforced plastic (CFRP), Glass fiber reinforced plastic (GFRP) and titanium alloy was conducted. A prototype cold cutting machine was fabricated and the weight was compared.
Simple Tests and Mechanical Model for Masonry Materials at High Temperatures
Authors: Andreini Marco , Sassu Mauro
Published: February 2014

An experimental procedure for tests on specimens made of several materials is performed to detect the mechanical properties depending from temperature. About 200 cylindrical specimens of several materials (clay, lightweight concrete, aerate autoclaved concrete, mortar) are tested from 20°C to 700°C. The free thermal strain and the decay of axial strength are determined; proposals for the stress-strain curves and the secant modulus of elasticity in function of temperature are illustrated. The data base from tests are able to calculate the collapse domains (bending moment - axial force - time of exposure to nominal fire) which represent a simple model for the assessment of masonry panel sections subjected to fire action.
Influence of Ammonia Solution on Zinc Oxide Nanostructures by Hydrothermal Growth
Authors: Huang Z.B. , Zou X.P. , Yang G.Q. , Lv X.M. , Wei C.L. , Sun Z. , Zhou H.Q. , Zhang B.L.
Published: February 2014

In previous work, ZnO nanorods and nanoflowers were synthesized on indium-tin-oxide (ITO) substrates by hydrothermal growth at low temperature ,using the different concentrations of equimolar (1:1) zinc nitrate Zn (NO3)26H2O and methenamine (C6H12N4) mixed as precursors solution, and adding ammonia solution to control the pH levels. In this paper, for comparison, the same experiment without ammonia solution was also discussed. SEM, XRD were utilized to characterize morphologies and crystal structures of ZnO. It was indicated that the pH of precursor solution leads to the significantly changes in the nanostructured ZnO. Besides, a hierarchical structure of some of the micro/nanotubes was obtained .The possible growth mechanism is discussed in this work.
Preparation of Magnetic Polymer ICF Pellet by the Electroless Plating
Authors: Cui Shao Bo , Lu Zhongyuan , He Feng Wei
Published: February 2014

The pretreating procedures on the inertial confinement fusion (ICF) pellet and the preparing procedures of th bath of electroless Ni-P plating were described in detail. The effects of the pH value of the bath on the coating quality, of the plating temperature on the yield of the coated microsperes and the plating rate, and of the plating time and the content of the complexing agent on the yield of the coated microsperes were investigated. The morphologies of the coating of the microsperes were evaluated by Olympus-BX51 optical microscopy (OM) and the coating thicknesses were measured by Scanning Electron Microscopy (SEM).
Foaming Ability of Rotomolding Polyolefin Resins
Authors: Pop-Iliev Remon
Published: February 2014

The main focus of the research presented in this paper is the investigation of the ability of various polyolefin resins to be converted into integral-skin cellular composites by using the rotational foam molding process. Integral-skin foamed rotational moldings are formally denoted as cellular composites ideally having a clearly distinct surface layer of solid skin of uniform thickness that is encapsulating a seamlessly coupled fine-celled foamed core or layer of uniform cell density and distribution. A systematic comparative material characterization study that attempts to derive practical guidelines about determining the roto-foamability of polyolefins that would be useful for rotomolding processors is presented. The study included two experimental methods of characterization, a melt rheology-based and a rotational foam molding processing-based. The experimental results from both implemented characterization methods revealed good agreement. A comprehensive insight into the key polyolefin material characteristics that would ensure satisfactory results if processed using the rotational foam molding technology have been provided. The experimental results revealed that high quality polyethylene (PE) based cellular morphologies can be obtained from both dry blended and melt compounded foamable compositions for both 6-fold and 3-fold expanded foams. Unlike PE resins, it was observed that successful foaming of polypropylene (PP) resins in rotational foam molding can only be successfully accomplished over a very narrow range of melt temperatures that are close to the melting point of the polymer and by using PP grades with a quite limited range of Melt Flow Rates (MFR).
Photo-Elastic Effects near the Centroid of Epoxy Specimens
Authors: Liou Chiou Lin , Wang Chaur Jeng
Published: February 2014

The stress concentration of the circular hole within the mechanical mart can easily derived by the photo-elastic technique if the testing specimen is sufficiently developed. The testing specimen using the characteristic of the photo-elastic coefficient, with actual form like the mechanical part by rapid prototyping forming is thus used in this paper. The rapid mold for prototype is made by the RTV-2 silicone gel associated with the vacuum chamber to remove the air within it. The testing scheme is by way of the simply supported beam where the load is imposed on the middle of the specimen. Results show that the smaller diameter of hole on specimen provides a larger stress concentration effect. When the diameter of the hole is small, the stress concentration effects caused by the machined hole and the forming hole have almost no difference. However, the stress concentration effects of the larger diameter of the machined hole and of the formed hole give significant difference, the stress concentration caused by the machined hole is much greater than one of the formed hole. In this paper, the actual shape of the specimen which is as same as the original mechanical components can be quickly obtained by the rapid prototyping technology for the photoelastic technique to reveal the experimental mechanics of real applications.
Preparation of Capacitor’s Electrode from Coconut Shell
Authors: Arie Arenst Andreas , Lee Joong Kee
Published: February 2014

Activated carbons were prepared from coconut shell by chemical activation method and utilized as electrode materials for electrochemical double layer capacitor (EDLC). A preliminary characteristic of activated carbon from coconut shell includes the Brunnaeur Emmett Teller (BET) analysis and cyclic voltammetry measurements. The BET surface area is not affected by the variation of activation temperature as both of the samples showed BET surface area of about 850-870 m2g-1. The N2 adsorption–desorption isotherms showed that the sample exhibited type I characteristics according to IUPAC classification, which confirms its micro-porosity. Compared with the un-activated carbon samples, the activated ones exhibited the better electrochemical properties with a specific capacitance of 150 F g−1 at a scan rate of 2 mV s−1. The good performance of activated carbon is attributed to the enhancement of surface area due to the KOH pretreatment which can open new pores accessible for the ionic transport
Parametric Studies on Effect of Trailing Liquid Nitrogen Heat Sink on TIG Welding of Steels
Authors: Sudheesh R.S. , Prasad N. Siva
Published: February 2014

Welding is an efficient material joining process. But the localised temperature rise up to the melting point in the vicinity of arc causes non uniform expansion and contraction resulting in residual stress and distortions. Post weld, Pre weld and in-process methods have been studied to reduce these unwanted effects of welding. A trailing heat sink is one such method. This consists of a cooling agent traversing at a constant distance behind the weld arc. Introduction of a cooling agent is reported to reduce the distortion. A liquid nitrogen jet is used as the cooling agent in the present study. A finite element model developed using Sysweld is used to study the effect of liquid nitrogen heat sink on weld distortions and residual stresses. The finite element model developed is used to make a parametric study on the effect of cooling jet radius, cooling strength and the distance between the jet and weld arc on out of plane distortions and stresses. Comparative study of the effect of cooling jet is made for mild steel (MS) and stainless steel (SS). It is observed that the out of plane distortions reduce with increasing cooling strength, jet radius. Reduction in distance between the jet and weld arc also causes a reduction in distortions.
Lithium Iron Phosphate Intelligent SOC Prediction for Efficient Electric Vehicle
Authors: Toha Siti Fauziah , Faezaa Nur Hazima , Azubair Nor Aziah Mohd. , Hanis Nizam , Hassan Mohd. Khair , Ibrahim Babul Salam Ksm
Published: February 2014

This paper presents modelling techniques for Lithium Iron Phosphate (LiFePO4) battery in an electric vehicle. Artificial intelligence techniques namely multi-layered perceptron neural network (MLPNN) and Elman recurrent neural network are devised to estimate the energy remained in the battery bank which referred to state of charge (SOC). The New European Driving Cycle (NEDC) test data is used to excite the cells in driving cycle-based conditions under varied temperature range [0-55]°C. Accurate SOC prediction is a key function for satisfactory implementation of Battery Supervisory System (BSS). It is demonstrated that artificial intelligence methods can be effectively used with highly accurate results. The accuracy of the modeling results is demonstrated through validation and correlation tests.
Determination of the Effect of Wall Heating Systems on Convective Heat Transfer Coefficient in Buildings
Authors: Acikgoz Ozgen , Kincay Olcay , Utlu Zafer
Published: February 2014

Decreasing energy consumption and advancing thermal comfort are the most important aims of building engineering. Previously reported studies by many researchers have found that different usages of convective heat transfer coefficient (CHTC) correlations in heating system simulations have considerable impacts on calculated heating load in buildings. Hence, correct utilization of CHTCs in real size room enclosures has great importance for both energy consumption and thermal comfort. In this study, a modeled room was numerically heated from one vertical wall and cooled from the opposite wall in order to create a real room simulation. While cooled wall simulate heat losses of the room, heated wall simulates the heat source of enclosure. Effects of heated and cooled wall temperatures and characteristic length on CHTC and Nusselt number in the enclosure were numerically investigated for two (2-D) and three dimensional (3-D) modeling states. CHTCs and Nusselt numbers of a real size room with the dimensions of 6.00 by 2.85 by 6.00 were found with FLUENT CFD and graphics of change were drawn. As result, difference between 2-D and 3-D solutions was found approximately 10%. This was attributed as the effect of air flow pattern effects over other surfaces in the enclosure that can not be counted at 2-D solutions. The change of CHTC at different characteristic lengths was illustrated as well.
Enhanced Alkali Pretreatment of Narrow Leaves Cattail by Response Surface Methodology
Authors: Sopajarn Arrisa , Sangwichien Chayanoot
Published: February 2014

The purpose of this work is to develop a pretreatment process of lingo-cellulosic ethanol production from narrow leaves cattail (Typha angustifolia) by using alkali catalysis with the response surface methodology (RSM) as a central composite design (CCD). The first step, LiOH, NaOH, and KOH were used as catalytic alkali for preliminary test. Second, the suitable alkali from first step was selected to optimize of pretreatment condition of three independent variables (alkali concentration, temperature, and residence time) that varies at CCD five codes (-2, -1, 0, 1, 2). Sodium hydroxide (NaOH) is the proper alkali because it could increase cellulose more than KOH and nearby LiOH while it is cheapest. RSM result shows the optimized pretreatment condition based on cellulose increased which obtained from this study that is NaOH 5 % w/v at 100 °C and residence time for 120 min. Beside, this condition was analyzed using an ANOVA with a second order polynomial equation after eliminated non-significant terms. At the optimized conditions, cellulose increased, hemicellulose decreased and weight recovery were achieved 77.81%, 80.59, and 41.65%, respectively. Moreover, the model was reasonable to predict the response of strength with less than 5% error.
Thermal Cycling Effect on Mechanical Properties, Grain Size and Residual Stress in Alumina and Yttria-Stabilized Tetragonal Zirconia
Authors: Zhang Jing
Published: February 2014

Alumina and zirconia are important materials for energy and optical applications. In this study, the effect of thermal cycling on grain size and residual stress was reported. Residual stress was measured using X-ray diffraction (XRD) sin2ψ method for the as-received and the samples after thermal cycling up to 900 cycles. For alumina, the measured residual stress is approximately 96 MPa in tensile for the as-received material, and increases to its highest value of 480 MPa after 650 thermal cycles. The residual stress decreases from 480 MPa to 96 MPa in tensile with increased thermal cycling from 650 to 900 cycles. The crystallized grain size calculated from the diffraction pattern shows that the mean crystallized grain size is about 93 nm for the as-received and increases to 232 nm after 650 thermal cycles. This result is consistent with the enlarged grain size observed by scanning electron microscopy for the alumina after 650 thermal cycles reported earlier. With continued thermal cycling up to 900 cycles, the crystallized grain size is greatly reduced to 104 nm. It suggests that evolution of the crystallized grain size is correlated with the residual stress. For yttria-stabilized tetragonal zirconia (Y-TZP), the mechanical properties at room temperature, are consistent with the property values provided by the manufacturer. The Young’s modulus of shows a non-linear inverse relationship with increasing temperature. The degradation of the Young’s modulus mostly occurs prior to 400 °C and to a less extent in the temperature range of 400 °C up to 850 °C. The Vickers hardness number for the as-received Y-TZP material decreases to a very small extent after 560 thermal cycles and increases approximately 2%, after 1200 thermal cycles. This is consistent with the trend of the Young’s modulus for thermal-cycled specimens.
The Synthesis of a Polyaspartic Acid Ester and Development of the Coatings
Authors: Liu Xiao Ping , Zheng Tian Liang
Published: February 2014

A new type of polyaspartic acid ester (PAE) was synthesized by double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) via a Michael addition reaction. The Fourier transform infrared spectrometer shows the reaction can take place in room temperature. The dynamics of the reaction were investigated by mercaptan-iodine titration analysis method at 57°C and 67°C. The results showed the reaction order between double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) was three. The solvent free polyaspartic polyurea coating was developed with the synthesized resin and the properties were tested with good results.
Control Strategy for Dual-Mode Electrical Variable Transmisson Hev during Mode Change
Authors: Tang Tian , Liu Hui , Han Li Jin
Published: February 2014

In this paper, a mode control strategy for a two-mode EVT hybrid electric vehicle (HEV) is proposed,considering transmission efficiency and mode change quality. First,speed and torque characteristics are analyzed by establishing relevant equations of two transmission mode. Next,the optimal operation mode is selected from the viewpoint of the transmission efficiency,when it is higher at a given speed ratio.Then,two scheme of operation sequence of clutch/brake are compared,and a control algorithm of synchronous control of two MGs and engine is suggested to reduce speed difference between both end of the clutch and torque fluctuation. A vehicle simulation based on Matlab/Simulink was performed to testify the mode change control algorithm of the dual-mode EVT HEV,and the simulation results showed that the mode control strategy for the dual-mode EVT HEV gave acceptable performance.
A Study of Waste-Heat Recovery Unit for Power Transformer
Authors: Chien Zi Jie , Cho Hung Pin , Jwo Ching Song , Chen Sih Li , Lin Yi Lun
Published: February 2014

This study discussed the feasibility of developing a system to circulate the heat loss from the coil and iron core of the power transformer equipped for buildings during power supply to the heat recovery unit. This study affixed a copper tube into the transformer insulating oil, allowing the water to circulate at normal temperature in the coil tube, and absorb the heat energy generated by the transformer coil and iron core. The heat energy was then recovered and stored. A low tension power transformer (7.5 KV) was used in the experiment. The operation was carried out in transforming power supply mode to seek for the most suitable recovery unit for various occasions. The test results showed that if the hot water recovery efficiency is 50%, in the course of producing hot water, the mean temperature of 17.5 L normal temperature water can be increased from 20°C to 50°C, thus producing 12.5 kJ heat only spends about 34 min. The results proved that the recovery unit for the heat from the power transformer can benefit from heating, prolong the transformer's lifetime, increase the power supply efficiency, and reduce the air conditioning load to save energy and to reduce global warming.
A Study on the Fish Pond Oxygenase System Driven by Wind Turbine
Authors: Chien Zi Jie , Cho Hung Pin , Jwo Ching Song , Chen Sih Li , Chien Chao Chun , Huang Xie Tai
Published: February 2014

This study developed an oxygenase system with horizontal-axis wind turbine driving the oxygenation device by belt pulley for aquaculture, and verified the feasibility of the system in conditions of Taiwan’s average wind speed. The experimental system is consisted of a horizontal wind turbine, a reciprocating compressor, and water channels. At the first stage of the experiment, the reciprocating compressor oxygenase system was measured according to the power supply standards in terms of power consumption, air displacement and oxygen production, in case of various rotating speeds and the compliance with aquaculture standards. At the second stage of the experiment, the wind turbine was used to directly drive the reciprocating compressor oxygenase system. According to the experimental results, regarding the test of the compressor oxygenase system, when power supply rotating speed is 406.7 rpm, power consumption is 234.5 W and the oxygen production is 7.48mg/L, which is above the level of amount of dissolved oxygen of aquaculture at 5.5mg/L. In case of driving the oxygenation device by wind power, when wind speed is 5.06 m/s and the wind turbine rotating speed is 140 rpm, the average dissolved oxygen in the water is 5.9 mg/L, which meets the aquaculture standards. Even in case of unstable wind speed, good oxygen production effects can be achieved. Moreover, the system is directly driven by wind power and does not require electric power.
Hydrogen Storage with Annular LaNi5 Metal Hydride Pellets
Authors: Kim Sun Woo , Kim Kwang J.
Published: February 2014

Thermal conduction capability of metal hydrides can be enhanced by 400 ~ 500% through pelletizing the metal hydride powder after a well-controlled copper-coating treatment. In this paper, pelletized LaNi5 metal hydride is studied to evaluate its heat transfer performance and hydrogen absorption rate. In order to analyze the transient heat transfer and hydriding reaction, numerical simulations are carried out based on a multiple-physics modeling. The reactor temperature variation and the dimensionless mass of absorbed hydrogen are plotted for different hydrogen gas supply pressures. The results are compared with the conventional powder-type metal hydride reactor.
A Fuzzy-PI Control Technique Designed for Power Control of Wind Turbine Based on Induction Generator
Authors: Aissaoui Abdel Ghani , Tahour Ahmed , Abid Mohamed , Essounbouli Najib , Nollet Frederic
Published: February 2014

In this paper, we develop the overall model of the wind energy conversion systems (WECS) structure based on induction generator (IG). The goal of this paper is to control the power generated by the WECS and transmitted to the grid. We propose a new control strategy based on fuzzy logic in order to control the power of the WECS. The main drawback is that the WECS is highly nonlinear. An adaptive Fuzzy-PI power controller is proposed to overcome this problem. A Simulation study is done to validate the strategy used in power control.
Feasibility of Using High-Intensity Ultrasound Assisted Biodiesel Production from Mixed Crude Palm Oil in Two-Step Process
Authors: Somnuk Krit , Prateepchaikul Gumpon
Published: February 2014

Biodiesel from a high free fatty acid (FFA) mixed crude palm oil (MCPO) can be produced to high fatty acid methyl ester (FAME) conversion by a two-step process. The first process is an acid-catalyzed esterification to reduce FFA in oil followed by a base-catalyzed transesterification process to produce biodiesel from esterified oil. In this study, the transesterification of esterified oil with methanol in the presence of potassium hydroxide (KOH) was performed in a 1,000 W ultrasonic homogenizer at a low frequency of 18 kHz. The use of high-intensity ultrasound to accelerate the reaction, the high surface power density of 1.62 W.mm-2 and the volumetric acoustic energy of 20 W.mL-1 were fixed. The objective of this study was to determine the various parameters (methanol concentration, KOH concentration, and initial temperature of oil) to produce the FAME conversion. The results showed that over 98 wt.% of FAME could be achieved with 5 g KOH/liter of oil, 15 vol.% of methanol, the total residence time of 20 seconds, and temperature of 30 oC. Moreover, the glycerides were rapidly converted to the FAME within reaction time of 10 seconds when the base-catalyst of 10 g KOH/liter of oil, and 20 vol.% of methanol were used. Consequently, the use of high-intensity ultrasonic irradiation can minimize the chemical cost, electricity cost, and reaction time.
The Influence of Resin Molds Fabricated with Different Forming Angle by Stereolithography on the Transmission Performance of Photonic Crystals
Authors: Chen Shi Bin , Li Di Chen , Wang Min Jie
Published: February 2014

In order to study the influence of fabrication accuracy on the transmission performance of photonic cystals, the resin molds with inverse diamond structure with the same size were fabricated in different forming angle (30°,60°,90°) by stereolithography (SL). The alumina PCs with diamond structure were obtained combining the molds and gel-casting. The results showed that different forming angle of three kinds molds resulted in the change of the size and relative angle of their cells, and the PCs fabricated were also. The transmission properties of PCs had an obvious change in the width and smoothness of the band gap, which displayed that the resin molds by SL resulted in fabrication errors would affect the transmission properties of PCs. In the practical fabrication of diamond-structure PCs, fabrication errors caused in the different forming angle needed to be considered when SL technology was utilized to fabricate the molds, which also fit complex molds.
Effect of Fiber Surface Treatment on Mechanical Properties of Polylactic Acid/Empty Fruit Bunch Fiber Biocomposites
Authors: Rosman Senawi , Sakinah Mohd Alauddin , Ruzitah Mohd Salleh , Iqbal Mohammad Shueb.
Published: February 2014

Renewable resourced green biocomposites are currently receiving much attention due to their environmental advantages. Therefore, the aim of this research is study the effect of fiber surface treatment on the mechanical properties of polylactic acid (PLA) biocomposite in order to produce a green biocomposite. Experiments were conducted by surface treatment of empty fruit bunch fiber using two methods, sodium hydroxide and silane. Both treated and untreated fibers were then melt compounded with PLA and mechanical properties of the biocomposite was studied. The results showed that silane treatment improved the reinforced biocomposite mechanical properties such as tensile strength by 33% and flexural modulus by 44% compared with untreated fiber reinforced biocomposites. This is due to the silane functional groups that act as a bridge between the PLA and fiber.
Design Considerations of in-Plane Nanoelectromechanical Switches with Corrugation Beams for Low Voltage Logic Applications
Authors: Qiu H. , Wang H.
Published: February 2014

Design consideration of nanoelectromechanical switches with low actuation voltage is presented. For a fixed-fixed beam structure design, it has been found that the actuation voltage can be largely reduced by integrating corrugations onto the fixed beam. An actuation voltage less than 3 V can be achieved with a relaxed design rule.
Control of Grid Voltage Feed-Forward and Crowbar Circuit for DC-Bus Voltage
Authors: Yang Xi Yun , Li Li Xia , Zhang Ya Min , Gao Jin
Published: February 2014

The DC bus voltage is the main criteria to reflect whether the converter system is working properly or not, and the stability control of the DC bus voltage is the key to ensure that wind power generators not take off the grid when grid voltage drops. This paper had done research on a direct-drive wind power system and proposed a coordinated control method based on the grid voltage information feedforward with a crowbar circuit. The hardware was combined with the improved control strategy in this method. When the grid voltage drops, the extra energy of the DC bus can be unleashed by the crowbar circuit, at the same time, the output power of motor-side can be controlled according to the grid-side information, and the mechanical speed of motor-side can be suppressed by the pitch angle regulation when the output power reduces. Thus, the DC-bus voltage can be keep stability. Results based on Matlab/Simulink simulation shows that this method not only improves the stability and dynamic response performance of the DC bus voltage, but also effectively maintains the output power of generator and reduces the action time of crowbar circuit. The ability of the wind power system riding through the grid fault has been effectively improved.
Thermoeconomic Analysis of Air Conditioning Systems
Authors: Cheng Wei Liang , Ji Hui , Di An
Published: February 2014

In order to decrease the operation costs of air conditioning systems, an evaluation model based on unit thermoeconomic costs of thermoeconomic theory is presented in this paper. By using real components and fictitious components in an air conditioning system, the relationships between the fuel and product are established, and then the operation performances of the air conditioning system can be analyzed and evaluated. The unit thermoeconomic costs can be obtained with the experimental data. The results show that the unit thermoeconomic cost of the system is the lowest when the vaporizing temperature is at 16.3°C, and the unit thermoeconomic cost of the compressor component is the highest. Therefore, the direction and emphases of the technique improvement and performance enhancement are provided.
Energy Consumption Distribution Research of a 600MW Supercritical Power Plant under Various Conditions
Authors: Duan Li Qiang , Pan Xiang , Huang Ke Xin , Yang Yong Ping
Published: February 2014

To identify the potential of energy conversation in power units, the energy consumption distribution model of supercritical power generation unit under various conditions are established based on a 600MW supercritical power generation system. Methods of unit energy consumption are applied and the total additional energy consumption is calculated under various loads, which varies from 30% TMCR load to full TMCR load. The energy consumption distribution of every heater in the boiler, cylinders of the turbine and the whole plant unit are analyzed. And the distribution rules of energy consumption of various conditions are revealed. The effects of key parameters on unit energy consumption are also investigated.
Solar Energy and Global Climate Change
Authors: Lin Jia Lin , Qian Tao Tao
Published: February 2014

Previous studies have shown that the solar energy input to the earth system underwent significant decadal variations at individual surface energy budget stations, with a global dimming from 1950s to 1980s, but a global brightening from 1980s to 2000s, and a mixed tendency at different locations thereafter. Here we use a new global gridded solar irradiance dataset to show that the previous results from individual stations represent well the regional means but not the global mean or hemisphere means. The global mean has a decadal variation that is quite different from the individual station results reported in previous studies, which comes from the fact that the southern hemisphere mean has an opposite trend with the northern hemisphere mean. No long-term global dimming trend is found associated with global warming
Assessment of Hydration Degree of Cement in the Fly Ash-Cement Pastes Based on the Calcium Hydroxide Content
Authors: Li Xiang , Yang Hua Quan , Li Ming Xia
Published: February 2014

The hydration degree of fly ash and the calcium hydroxide (CH) content were measured. Combined with the equilibrium calculation of cement hydration, a new method for assessment of the hydration degree of cement in the fly ash-cement (FC) pastes based on the CH content was developed. The results reveal that as the fly ash content increase, the hydration degree of fly ash and the CH content decrease gradually; at the same time, the hydration degree of cement increase. The hydration degree of cement in the FC pastes containing a high content of fly ash (more than 35%) at 360 days is as high as 80%, even some of which hydrates nearly completely. The effect of water-cement ratio to the hydration degree of cement in the FC pastes is far less distinct than that of the content of fly ash.
Simulation of a Double-Fed Induction Generator Wind Energy Conversion System under Healthy and Faulty Conditions
Authors: Giaourakis Dimitrios G. , Safacas Athanasios , Tsotoulidis Savvas
Published: February 2014

In this paper, the operation of a wind energy conversion system (WECS) incorporating a Double-Fed Induction Generator (DFIG), under various wind speeds and faulty conditions, is investigated through simulation. In this study the simulation of such a system (DFIG-WECS) was held by using the software Matlab/Simulink.. The simulation results are presented and evaluated for the issues of fault diagnosis and identification. More specifically, a DFIG-WECS has been simulated under various wind speeds and when a short-circuit occurs in the back-to-back converter and in the DC link from the point of view of these issues. In this work, it has been concluded that the investigated faults have caused a specific and unique harmonic content in grid, rotor and stator phase currents, which could be used for fault diagnosis and identification.
Analysis of Influence on Urban Low Voltage Distribution Network from Charging Equipment of Electric Vehicle
Authors: Gao Kun , Yuan Liang , Zhang Zhe Nan , Wei Han Bing
Published: February 2014

For sake of analyzing influence on load characteristic of urban low voltage distribution network from extensive popularization of charging equipments of electric vehicles, this paper establishes probability density distribution load characteristic model of charging equipment. Taking representative distribution lines and transformer areas with residential and commercial users for instance, summer daily load curves are described and charging load are forecasted, and basic load curves and charging load additional demand curves are peak-valley superimposed according to respective traits, further more, the influence on distribution lines and transformer areas from charging load of electric vehicles with different ages, finally, suggestions are put forward of urban low voltage distribution network planning and charging equipment supervisions.