bluuebunny/crossref_metadata_2025 huggingface dataset:
Bending Study for Axially Symmetric Tapping Plates with Uniform Load at All Crown by Transfer-Matrix Method
Authors: Suciu Mihaela
Published: February 2012

This paper presents a study of the axially symmetric plates, charged with uniform load by Transfer-Matrix Method. The analytical calculus is based of the theory of Dirac’s and Heaviside’s functions and operators. That is an important possibility to result the circular plates, with the opportunity to program the calculus to obtain the eight elements of the exterior circumference state vector and for the interior circumference state vector of a tapping plate. After, we can calculate for all the values r0<r<R, all the elements for the state vectors.
Implementation of RFID-Based Access Control Management System
Authors: Lin Hai Yun , Wang Yu Jiao , Bi Jian
Published: February 2012

Along with the increasing number of Chinese automobiles in cities, the vehicle management becomes a difficult issue. The effective management on vehicle is to identify the vehicle. RFID technology can be used for the access control management, which can serve an effective way to identify the vehicles, making access control management of the security protection more effective and intellective[1] . Access Control System based on RFID protocol is proposed, and then introduces a model of system and gives a brief description of each component of the model, A detailed explanation about the implementation of each model is given.
New Inverter Fault Current Limiting Method by Considering Microgrid Control Strategy
Authors: Najafzadeh Kaveh , Heydari Hosein
Published: February 2012

In this paper we present an approach for fault current limiting (FCL) in inverters of a Microgrid. For this purpose, which is based on the control system employed in Microgrid, we select the proper FCL technique. In this research it is represented that FCL inverter current with limited magnitude of id and iq that are used in PQ control don’t have a good behavior in V-F controlled DG. Current limiting by decreasing the output voltage of DG is performed by the value of inverter reduction of the voltage that is selected by paying attention to the maximum current that is allowed through inverter, this value is two times of the rated current of inverter
Performances Evaluation for a Reversed Quasi-Carnot Cycle (Refrigeration Machine) by Using the Direct Method from Finite Speed Thermodynamics
Authors: Petrecu Stoian , Dobre Catalina Georgiana , Tirca-Dragomirescu Georgiana , Costea Monica , Stanciu Camelia , Feidt Michel
Published: February 2012

The Direct Method from Finite Speed Thermodynamics is used in order to Determine in a complete analytical format of the COP and consumed Power of a Reversed Cvasi-Carnot Cycle (Refrigeration Machine with vapor) taking into account internal irreversibility generate by: Finite Speed, Friction, Throttling and Internal Heat Loses.
Researches on a New Type of Rotating Thermic Motor
Authors: Băran Nicolae , Duminică Despina , Besnea Daniel
Published: February 2012

The paper presents the constructive solution and the functioning principle of a new type of rotating motor that integrates an energy cogeneration plant. Mechanical power developed by the motor and the steam flow rate needed for the driving of the rotating motor are computed. Finally, there are determined the constructive and functional parameters of this type of motor, that represents the purpose of a scientific research contract in 2011.
Technical Options for Off-Grid Electricity Supply
Authors: Altawell Najib
Published: February 2012

Various types of DG technologies, their viability and other important aspects, such as the economical and performance side have been examined in this paper. The main aim and objective of this workis to find the most suitable off-grid system for rural electrification, i.e. in the form of technical feasibility, acceptable purchasing/installation and maintenance cost, as well asreliability. The selected system should be able to provide continuous electricity supply, particularly in areas where main grid connection is not a viable option. The result from this work has concluded that hybrid renewable energy systems are the best approach in solving some of the problems related to electricity shortage in the countryside. Hybrid systemsconstruction means that sustainable energy and environmental protection will be part of the overall commercial and non-commercial applications for off-grid electricity supply
The Dynamic and Lightweight Design of the Support Structure of Electric Vehicle’s Power System
Authors: Zhu Wei Hua , Liu Jun Ying , Feng Jin Zhi
Published: February 2012

The development of Electric Vehicle is not only a replacement of power source, but a new process of reasonable design and development on the mechanical structure and power system. Considering the strained condition of the support structure when the Electric Vehicle is under the four typical working conditions: accelerating, braking, steering and vertical impact, the dynamic design method and finite element theory are adapted to analysis its strength and mode, while the orthogonal test method is used to analyze the influencing factors of its modes. Combining the size optimization, the weight of the power system’s support structure has been reduced. This method, which has been adapted in the independent development of an Electric Vehicle，will provide a useful reference for the dynamical and lightweight design of similar mechanical structure.
The Flexural Behavior Study of Composites Material in Static Three-Point Bending Test
Authors: Chaouche Mohamed , Merzoug Bachir , Bezazi Abderrazak
Published: February 2012

The effect of the plies number and the thickness on ﬂexural properties of glass fiber reinforced polyester or epoxy composites has been investigated experimentally. Laminates were fabricated by hand layup technique in a mould under light pressure and followed by curing at room temperature for 8 hours. Laminates were made with a different number of plies, by varying the number of glass layers and the thickness so as to obtain different total ﬁber weight fraction. Tests were conducted on a hydraulic universal testing machine, Zwick Roell type 50 kN capacity, using automatic data acquisition software. The results indicated that the plies number and the laminate thickness have a great effect on ﬂexural properties. An overall comparison between the flexural properties of all the laminates which have the same design revealed that the glass/epoxy laminates have better properties than those of glass/polyester laminates. It is found that the behavior of these laminates is dominated by damage mechanisms such as delamination, buckling and fiber rupture.
The Synthesis and Ion-Exchange Property of Li+ Memorized Inverse Spinel Al2.6667Ti(PO4)4
Authors: Jiang Jin He
Published: February 2012

Compound Al2.6667Ti(PO4)4, a inverse spinel-type metal compound, was prepared by a solid state reaction crystallization method. The Li+ extraction/inserti on with this material were investigated by X-ray, FT-IR spectroscopy, and Kd measurement, The chemical analysis showed that the Li+ extraction insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 8.0mmol/g for Li+. It had a memorial ion-sieve property for Li+.
Shear Behaviour of RC Beams Strengthened with FRP Materials
Authors: Dong Jiang Feng , He Dong , Yuan Shu Cheng , Wang Qingyuan
Published: February 2012

This paper reports the results of a research work aimed at examining the use of externally bonded of fiber reinforced polymer (FRP) sheets, consisting of carbon FRP (CFRP) and glass FRP (GFRP), as a strengthening solution to upgrade the shear capacities of reinforced concrete (RC) beams. A total of 7 RC beams were constructed and tested under four-point bending, i.e. two reference beams with different concrete strength and without any FRP sheets, one beam reinforced by GFRP sheets and four beams reinforced by CFRP sheets. Externally bonded FRP shear strengthening was found very effective in upgrading the shear strength of the beams strengthened. The shear strengths of RC beams strengthened were improved greatly by FRP sheets, and the strength gain caused by the FRP sheets was in the range of 31-74%. Test results also show that the more ductile behaviour and higher ultimate strength are obtained for the beams with FRP shear strengthening by using high concrete strength.
A STATIC-LEACH WSNs for Hazardous Materials Monitoring
Authors: Hui Fei , Wang Xiao Le , Shi Xin
Published: February 2012

In this paper, hazardous materials transportation monitoring system is designed, implemented, and tested using Wireless Sensor Networks (WSNs). According to energy consumption and response time during clustering of Wireless Sensor Networks LEACH (Low Energy Adaptive Clustering Hierarchy) routing protocol, we proposed STATIC-LEACH routing protocol based on static clustering, it can effectively reduce energy consumption of the wireless sensor nodes and reduce network latency of cluster. With WSN and GSM/GPRS, low cost and easy deployment remote monitoring is possible without interfering with the operation of the transportation.
Dielectric Properties of Barium Titanate Ceramics Modified by CuO in Different Methods
Authors: Su Dan , Wang Yu , Chen Wan Ping , Chan Helen Lai Wah , Bing Li Na
Published: February 2012

CuO has been doped solely and together with BaO and SiO2 into barium titanate by mixing and calcination. X-ray diffraction showed that the sample doped by CuO-BaO has stable second hexagonal phase while the samples doped by CuO, CuO-SiO2 were of a pure perovskite phase. For CuO-BaO doping, the Curie temperature was decreased accompanied with higher εmax; while for CuO doping and CuO-SiO2 codoping, the Curie temperature was increased with εmax decreased. The difference can be explained considering that Cu2+ ion could not only incorporate into the BaTiO3 lattice, but also assemble in the boundary phase when CuO was doped solely. Besides, the mechanisms of CuO doping and SiO2 doping could happen at one time.
The Sliding Frictional Contact Problem in Two Dimensional Graded Materials Loaded by a Flat Stamp
Authors: Khajehtourian Romik , Adibnazari Saeed , Tashi Samaneh
Published: February 2012

In this article, the sliding frictional contact problem for a half-plane which is graded in two dimensions is studied. The effect of medium properties gradient and coefficient of friction in contact mechanics of two dimensional (2D) graded materials which is loaded by a flat stamp have been investigated by developing two Finite Element (FE) models, in macro and micro scales. Discretizing the graded half- plane by quadrants for whose material properties are speciﬁed at the centroids by Mori-Tanaka method in both directions has been used to model the 2D FGM in macro scale. In micro scale, the ideal solid quadrant particles which are spatially distributed in a homogeneous matrix used to model the FGM structure. Also, boundary conditions and loading of both models are the same. The study is focused on determining the contact stress distributions on contact surface. The contact mechanic problem of 2D graded materials has been solved and the results are presented for various combinations of friction coeﬃcient and material non-homogeneity constant parameters Analyses and comparison of the results showed that micro and macro scale results are in a very good agreement.
Aluminium Alloy Matrices Reinforced with Coated Particulate Silicon Carbide
Authors: Yang Peng Yuan , Chen Yu Hong , Chen Bin
Published: February 2012

The low-cost production and performance of 6061-aluminium alloy matrices reinforced with coated silicon carbide particulate has been studied. The micro-wave vacuum sintering was adopted to prepare the composite in order that the loss ignition is very small. The effect of copper coated silicon carbide has proved beneficial to interfacial bonding and improved the mechanical properties. Differences in the fracture characteristics of specimens containing coated and non-coated particles were observed. The particulates size has much influence on mechanical properties.
Comparative Solid Particle Erosion Characterization of Conventional and Nanostructured Al2O3-13wt.%TiO2 Ceramic Coatings Fabricated by Plasma Spraying Process
Authors: Wang Dong Sheng , Tian Zong Jun , Wang Song Lin , Shen Li Da
Published: February 2012

Abstract. In this work, conventional and nanostructured Al2O3-13wt.%TiO2 coatings were deposited by the plasma spraying technique. The microstructures of the two types of coatings were analyzed, and the solid particle erosion behaviors of the two coatings were comparatively researched in an erosion tester. Meanwhile, the erosion failure mechanisms of the coatings were discussed. The results show that the traditional coating has laminated structure and some pores. However, the nanostructured coating possesses a denser structure and not obviously lamellar-like structure, and exhibits a bimodal microstructure consisted of fully melted regions and partially melted regions. Owing to the compact microstructure and remained nano-particles, the nanostructured coating had a better erosion wear resistance than the conventional coating. Eroded morphology analysis indicates the main erosion mass loss of the coatings is attributed to lamellar spalling of the sprayed splats and fracture of brittle ceramic particles. In addition, the nanostructued coating has some impact craters and plough marks. In terms of the erosion mechanism, the conventional ceramic coating is dominated by brittle erosion, while the nanostructured ceramic coating is dominated by brittle erosion as well as ductile erosion to some extent.
Fabrication and Characterization of ZnO Nanorod Arrays Grown on Nickel-Coated Polyester Fiber
Authors: Wong C.P. , Mak C.L.
Published: February 2012

Vertical-aligned arrays of zinc oxide (ZnO) nanorod were grown on nickel-coated polyester s for future development of ZnO nanorod-based solar cells. ZnO nanorods with aspect ratio of three were deposited by chemical solution deposition (CBD). Besides, an underlying ZnO seed layer was introduced to grow large-area and continuous layer of ZnO nanorods using pulsed laser deposition (PLD). Structurally, dominating XRD diffraction of the ZnO nanorod arrays was occurred at lattice plane (002) and a specific Raman spectrum was also obtained. Optically, bandgap energy of the ZnO nanorods was 3.95 eV. The ZnO nanorods with full-width at half-maximun (FWHM) of about 16 nm were excited normally from ultraviolet laser source of λ=266 nm and released edge-emission of λ=383 nm. On the basis of our results, high quality ZnO nanorods have been successfully fabricated on nickel-coated polyester fibers.
Preparation and Properties of Halogen-Free Flame Retardant Blending Modification Polyester
Authors: Chen Sheng , Su Min , Lan Jian Wu , Zheng Qing Kang
Published: February 2012

Phosphorous-containing flame retardant additive for polyethylene terephthalate (PET), hexa(phenylamino)cyclotriphosphazene (HPACP) was synthesized by substitution reaction of hexachlorocyclotriphosphazene (HCCP) with aniline. The melting temperature of HPACP are 279.2°C, and HPACP possesses of favorable thermal stability. Flame-retardant effect of HPACP on PET was investigated by Differential Scanning Calorimetry (DSC) and Limit Oxygen Index (LOI) methods. With the content of flame retardant HPACP increasing, the melting enthalpy of PET reduced, while the melting temperature and onset temperature showed a decreasing tendency. With the weakening of melt dripping phenomenon, LOI of PET/ HPACP flame retardant systems increases with the increase of content of HPACP. LOI of PET containing 10 wt% of HPACP is 28.3.
Preparation and Properties of Nanocomposites Based on Poly(Lactic Acid) and Modified TiO2
Authors: Buasri Achanai , Chaiyut Nattawut , Kritsanakun Chanon , Phatkun Chettha , Khunsri Tiwiwan
Published: February 2012

In this study, poly (lactic acid) (PLA)-TiO2 nano particle nano composites were prepared and the severe aggregation of TiO2 nano particles in polymer matrixwere reduced by themodification of TiO2 surface with propionic acid and n-hexylamine. The resulting products were characterized by FT-IR, DSCand SEMtechniques so as to have a better understanding of bondingbetween the polymer and nano particles. All of nano composites with a wide range of TiO2 additionexhibit the high transparency. SEM micrographs of the nano composites showed of the TiO2 nano particles were uniformly dispersed in polymer matrices. Photodegradation of PLA-TiO2 nano particle nano composites were also investigated. The results indicated that nano composites could be efficiently photodegraded by UV irradiation in comparison with pure PLA.
The Effect of N Vacancy on GaN Doped by Fe
Authors: Wang Yu Feng , Yang Chong , Guo Ting Ting
Published: February 2012

Using general graduated approximation (GGA) of the ab-initio based on density functional theory (DFT), three models of possible double Fe doping GaN and three models of possible N vacancy and double Fe codoping GaN were calculated. The results show that in the three models of double Fe doping GaN, the energies of antiferromagnetism (AFM) are lower than the ones of ferromagnetism (FM), which shows that the ground state of Fe doping GaN will be AFM, this agrees on the conclusion of literature [15]. After adding vacancies 2 and 3 respectively, we found a ferrimagnetic (FIM) ground state. But after adding vacancy 1, the ground state was still AFM.
Unified Stresses Solution for Sheet Forming
Authors: Li Xiao Wei , Zhao Jun Hai , Wang Qi Yao
Published: February 2012

Based on unified strength theory, the unified stresses solution for sheet forming is presented according to mechanical analysis developed, and accurate enough for much material due to the contributions of both intermediate principal shear stress and varying tension-compression-ratio included. Notably, by denoting a notation of h, the expressions presented to estimate stresses of billet for sheet forming can be apply to both drawing and extrusion. In addition, when material has identical strength in tension and compression, i.e., the tension-compression-ratio of the material is equal to unit, the stresses solution based on unified strength theory become that based on unified yield criterion. Accordingly, it can be proved that the stresses solution based on Mises criterion is just a special case of that based on unified yield criterion.
Evaluation of Different Geometry of Received Pulses from CdZnTe Semiconductor Detectors
Authors: Fayaz Vahid , Amirabadi Morteza
Published: February 2012

The semiconductors have conductions ranged between the conductors and nonconductors. Conduction makes the semiconductors one of the most important materials for electric applications. Therefore, with the receiving pulses from cathode in different geometries such as Cartesian, cylindrical and spherical the most commonly used pulse is the pulse created by the detector with cubic geometry.
Based on ABAQUS Five Axis Milling Process Dynamics Modeling and Analysis
Authors: Chen Geng Shun , Lv Yi
Published: February 2012

Article in the first quantitative analysis of milling process of material removal on the work piece model effects, using matrix perturbation theory gives the work piece modal approximation, fast algorithms. Major sources of uncertain factors analysis of milling process, based on the interval algebra, derivation of the work piece (or tool) interval characteristics of matrix, the use of interval finite element method for calculating the tool dynamic response of upper and lower bounds. Modal experimental results and theoretical predictions dovetailed.
Comparison of Different Residual Stress Models of FSW Butt Joints for Thin Aluminum Alloy Plates
Authors: Wang Xi Jing , Li Na , Zhang Zhong Ke , Ruan Guo Jing
Published: February 2012

At present, the main methods used to predict welding residual stresses are the three dimensional thermo-elastic-plastic FEA method and the inherent method.Many learners had simulated the residual stresses of FSW used the thermo -elastic-plastic FEA method which was proved to be time consuming and not very effective. The inherent strain method neglects the whole welding process, and predicts distortion using an elastic finite element analysis by applying the inherent strains on the structure. In this paper,the inherent strains are firstly obtained for an flat butt-joint of aluminum alloy through experiments and three dimensional thermo-elastic-plastic FEA. Computational and experimental results showed that the inherent strain method could predict welding distortion with acceptable accuracy and greatly reduced running time when comparing to the thermo-elastic-plastic FEA method.
Contour Errors during Milling Process
Authors: Marin Doina , Predincea Nicolae
Published: February 2012

To achieve high quality and productivity during continuous contouring, it is important to know how the two axes work together to move the machine in a circular or rectangular path. For this reason, we have analyzed circular and linear motion trajectories and the frequency response of the system during milling process. In the same time, is required to analyses simultaneously both mechanical and control subsystems. Based on these problems, the main objectives of this work have been defined to find a way to improve dimensional accuracy.
Oxidation Behaviors of Dusts Generated in Different Cutting Processes of Silicon Ingots
Authors: Yin Chuan Qiang , Wei Xiu Qin , Xiong Yu Hua , Zhou Pan Bing , Zhong Gen Xiang , Zhou Lang
Published: February 2012

Large amounts of silicon dusts, including band saw dusts, grinding dusts and wire saw dusts were generated in photovoltaic industry. Recovery of pure silicon from the dusts is of great value to industry, and understanding their oxidation behaviors is essential for such recovery. The present paper reports our investigations into the oxidation status of the as-generated dusts and their oxidation kinetics in further exposure. Hand-ground multi-crystalline silicon fine powders from broken wafers were used as reference. And the oxidation behaviors of the reference silicon powders were also discussed. The results show that severe oxidation on the surface of the band saw and grinding dusts occurs due to the existence of the aqueous medium. With the storage time prolonged, the oxidation increases rapidly in the aqueous medium in the ambient temperature initially, and then it drives to stabilize. While no obvious oxidation appears in the wire saw dusts due to the protection of PEG (polyethylene glycol). With the PEG concentration in the liquid medium increased, the oxidation degrees of the multi-crystalline silicon fine powders are decreased. Based on above knowledge, an efficient suppression of oxidation of band saw and grinding dusts was proposed lastly.
Prediction of Surface Finish and Optimization of Machining Parameters in Turning
Authors: Prasad Devi , Krishna Prasad , Rao Shrikantha
Published: February 2012

Surface roughness plays a crucial role in the functional capacity of machined parts. In this work, experiments were carried out on a conventional lathe for different cutting parameters namely feed, spindle speed, depth of cut and tool nose radius according to Taguchi Design of Experiments. Radial acceleration readings were taken with an accelerometer. Optimum cutting parameters and their level of significance were found using Taguchi analysis (ANOVA). Regression analysis was carried out to identify whether the experimental roughness values have fitness characteristic with the process parameters. Recurrence Plots (RP) were obtained using the sensor signals which determine surface roughness qualitatively and Recurrence Quantification Analysis (RQA) technique was used to quantify the RP obtained. Surface finish was predicted using a feed forward back propagation neural network with RQA parameters, cutting parameters and acceleration data as inputs to the network. The validity and reliability of the methods were verified experimentally.
Study on Influence of Paper Fillers on Ink Transfer
Authors: Liang Quan Feng , Ding Guo Hua , Zhong Han Mei
Published: February 2012

This paper uses the culture paper commonly-used filler PCC (precipitated calcium carbonate) and makes a good ratio of other raw materials and dosage of various other chemicals. Under the certain papermaking craft condition, with the certain quantum, the experiment changes the filler proportion of the paper to make paper samples and test the samples’ properties and the printing ink transfer.The experiment establishes an influence curve relationship, through that we analysis and draw the conclusion when the proportion of PCC is in the range 20% to 30%, it will get better ink transfer effect, which will provide reference for actual production.
Study on Processing Properties of Epoxy Resin System in VARI
Authors: Zhao Chen Hui , Zhang Guang Cheng , Sun Wei Min , Shi Ai Hua
Published: February 2012

As a low cost moulding technology, VARI is widely used to produce advanced composite materials. At the same time, the particularity of VARI process make it have particular requirements on resin system. Epoxy resin system attracts extensive attention because of its good process performance. Curing reaction and rheological behavior of epoxy resin system were studied by DSC and viscosity experiments. The results showed that resin viscosity decreased from 2600 mPa•S at 15°C to 600mPa•S at 40°C . Viscosity of resin system rose about 0.5Pa•s within the first 2h. Gel time shortened dramatically when the temperature exceed 60°C. the curing temperature is 60°C be based on DSC curve and gel time-temperature curve. Resin cast plate of epoxy resin system has good mechanical properties of compression strength.
Fabrication of Nanomaterial Devices for Field Emission Applications
Authors: Choi Yong Ho , Kim Kwang Hyun
Published: February 2012

Nanomaterials such as 1-dimensional nanowires and nanotubes and 2-dimensional graphene are the promising materials for novel device developments due to their unique physical and chemical properties. For field emission applications, nanomaterials are excellent candidate for an electron source by advantages of their small dimensions and high aspect ratios. In this study, we used GaN nanowires as the nanomaterials synthesized by Vapor-Liquid-Solid method. The field emission devices were then fabricated using the general Si microfabrication techniques. Moreover, the field emission properties of the GaN nanowires were characterized using cold field emission theory. It is demonstrated that the fabrication techniques shown in this study are efficient to fabricate field emission devices using nanomaterials.
Sodium Nitrate Assisted Hydrothermal Synthesis of Na0.5Bi0.5TiO3 Nanoflakes
Authors: Yang Lin Lin , Wang Yong Gang , Wang Yu Jiang
Published: February 2012

Single-crystal Na0.5Bi0.5TiO3 nanoflakes have been successfully synthesized at 160°C with 8M NaOH by a hydrothermal method assisted by sodium nitrate. The as-prepared samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The presence of sodium nitrate was found to play an important role in the growth of single-crystal Na0.5Bi0.5TiO3 nanoflakes.
The Effects of Heteroatom-Doping in Stone-Wales Defects on the Electronic Properties of Graphene Nanoribbons
Authors: Wang Zhi Yong
Published: February 2012

The effects of boron(nitrogen/silicon)-dopant in Stone-Wales defects on electronic properties of graphene nanoribbons are investigated by using density functional theory. It is shown that the geometry structures and band structures have changed distinctly for these complex configurations. Interestingly for the dopant site 1, the distortions of boron/silicon-doping configurations are larger than that of the nitrogen-doping configurations, which affects the band structures of these configurations. The theoretical results may be valuable for the design of electronic devices.
Impact Test in Working Space of Milling Center
Authors: Marin Doina , Predincea Nicolae , Marin Dan Mihail
Published: February 2012

Experimental modal analysis is quickly developed area of science in last years. Experimental approach for solving technical problems is a means to estimate or evaluate modal properties of a mechanical structure. The paper is focused at dynamic properties of milling centers, namely at the resonance frequencies and vibration shapes of a simplified tool-work piece system. All this properties are identified by measurements. The machine tool vibration was excited by impulse force and a response of excited vibration was recorded. The measurement points for vibration were selected at the spindle head, the table and the clamping device. The paper aims to present comparative results of theoretical studies with experimental results obtained from impact test to the machining centers.
Effect of HF Concentration on Corrosion Resistance of Biomedical Implants
Authors: Assadian Mahtab , Idris Mohd Hasbullah , Mehraban Saleh , Jafari Sajjad , Kadir Mohammed Rafiq Abdul
Published: February 2012

This work compared the variation of weight of Mg 1%Ca as cast in different concentrations of hydrofluoric acid (HF) such as 45% - 40% - 35% - 25% - 20 % - 13% - 7 % for 24 h at room temperature to be utilized in biomaterial application like hip, knee implants that have effect on corrosion resistance. By immersion Mg 1%Ca alloys in HF, the layer of MgF2 was constituted on the surface of alloy and this layer improves the corrosion and causes weight gain. The results show that in order to get a better corrosion resistance, surface treatment should be done in 40% of HF, because the weight gain is more than other HF concentrations.
Efficiency Improvement of Three-Junction Photovoltaic Cell Based on Gallium-Phosphide-Oxide, Indium-Gallium-Arsenide and Indium-Gallium-Antimonide
Authors: Abdulla-Al-Galib Mir , Salam K. M. A. , Awal Mohammad A. , Sayeed Kazi Abu
Published: February 2012

In this research paper we present a new high efficient three-junction photovoltaic cell with anti-reflective coating. The aim of our research work is to improve the photon absorption and reduce the photon reflection as well as the trasmission. The use of anti-reflective coating (ARC), Gallium-Phosphide-Oxide on the photovoltaic cell based on InGaAs/InGaSb has increased the photon absorption significantly. In this work we have analyzed the photon absorption, photon reflection and photon transmission of existing high efficient solar cells. Real Time Photonics Simulator has been used to simulate the performance of the solar cells. The simulation results show that with the inclusion of Gallium-Phosphide-Oxide on the multi-junction photovoltaic cell the photon absorption increases significantly. Our three-junction photovoltaic cell based on GaPO/In0.53Ga0.47As/In0.5Ga0.5Sb shows dramatic improvement of photon absorption in the range of 479nm – 767nm wavelength of the solar spectrum. With the addition of GaPO in place of GaP we see a tremendous increase of photon absorption, which significantly increases the efficiency of the photovoltaic cell
Prehensile and Stepping Mchanisms for Rbots, Based on Bomechanisms
Authors: Luca Liliana , Popescu Iulian , Ghimişi Stefan
Published: February 2012

It presents the mechanisms of the bird’s legs, by exemplifying with the parrot. It gives structural data and they are written mathematical relationships which are necessary to write the calculations of these mechanisms. It shows how these mechanisms can be used as prehensile mechanisms, but also as stepping mechanisms. Such mechanisms can be used, for example, for the robots that are displaced on narrow bars.
Preparation of Precursor of Lini0.5mn1.5o4 with High Density
Authors: Miao Chao Lin , Shi Lu , Chen Gai Rong , Dai Dong Mei
Published: February 2012

The precursor of LiNi0.5 MnSubscript text1.5O4 cathode material with high density was synthesized by two-dryness co-precipitation method. The optimized parameters were found out by studying the relationship between the density of precursor and the concentration of reactants, the manner of adding agglomerating agent, the remaining water in filter cake and the manner of dryness. The highest density (1.74 g/cm3) of precursor can be achieved under optimized condition: NiSO4 0.375 mol/L, coagulation agent added with little amount but many times, 28% of water in filter cake and two-step dryness, which is much better than that made by other methods. Our experiment provides a significant reference for the synthesis of excellent-performance cathode materials of lithium-ion battery. LiNi0.5 MnSubscript text1.5O4has a good cycle performance, a higher discharge capacity and a discharge platform of 4.7v, so it has become a research focus of 5-voltage cathode materials in the field of lithium ion battery recently.[1-4] However, LiNi0.5Mn1.5O4 prepared by common methods usually has a lower tap volume capacity.[5-9] HiroyuKi Ito[6] reported a continuous fabricated high-density cobalt-manganese-doped nickel hydroxide method with which the density of product was between 1.5-1.91g/cm3, however the used ammonia as a complexation agent in the preparation process not only increased the cost of the preparation, but also led to environmental pollution. Research results show that the cathode material synthesized using high-density precursor has a higher tap density, a larger volume capacity and a good electrochemical performance.[10] In this paper, we find out the optimized parameters of preparation of precursor of LiNi0.5 MnSubscript text1.5O4 by studying the relationship between the density of precursor and concentration of reactants, the manner of adding agglomerating agent, the remaining water in filter cake and the manner of dryness.
Review State of Biomass Energy in Iran
Authors: Asadi Mohammad Reza , Moharrampour Mahdi , Abdollahian Heidar
Published: February 2012

The presence of biomass resources and benefiting from such energy producing sources in every country supply a part of country’s energy needs, reduce its environmental effects and cause creation of new jobs. In this regard this paper presents the state of biomass energy in Iran. Results of this study shows that the major biomass resources in Iran are agricultural solid wastes (%59), animal wastes (%28), corrupting waste materials (%11) and civil and industrial waste waters (%2). According to statistical data, the potential biomass energy in Iran is equal to 15 million ton of crude oil which will be estimated about %13 of annual Iranian crude oil sale. The project of survey the potential and feasibility of energy obtaining out of burring solid wastes of Mashhad and Shiraz are executive activities of biomass in Iran and also survey the potential and feasibility of energy obtaining out of burring solid wastes of other cities of Iran and installation of biomass power plant are future activities of biomass in Iran.
Ultrasonic Ion Pumps in Bio-Battery’s Electrolyte
Authors: Amjadi Ahmad , Ebrahimi Afsoon , Sherafati Arefe , Khalilgharibi Narges , Zand Mani Karimkhan , Dibazar Mohammad Sadegh Satari , Omid Sobhani Seyyed
Published: February 2012

Bio-batteries are environmental friendly electricity generation devices that utilize energy from biological sources , like glucose[1][2]. It consists of an anode with digesting enzymes and a cathode comprising oxygen-reducing enzymes. Immobilizing enzymes is a considerable issue in these kinds of devices. In this article, we propose two new methods for immobilizing and shifting particles likewise enzymes used in bio-batteries towards the anode or cathode end. Our experiments illustrate how tiny particles could be trapped in the nodes of the ultrasonic standing waves and by two methods of displacing the nodes, we can transfer the particles towards a desired location. First method is based on sweeping the frequency of the operation to the higher frequency and the second is based on changing the circuit phase. The above-mentioned methods can be used instead of the other common method in which certain polymers is applied for this purpose. Using these polymers are not economically commodious and makes bio-batteries too expensive[1]. We hope suggested methods lead to wide spread production of bio-batteries in near future and in more efficient ways than they are currently being produced
Design and Anaysis of Thermoacoustic Air Conditioning System as Environmental Friendly Device
Authors: Mat Salleh M. , Hamidon R. , Zain M.Z.M. , Khee H.S.
Published: February 2012

Thermoacoustic air conditioning system is a new technology design of cooling system which offers the possibility for simple and efficient energy conversion devices. This research is looking an alternative for CFC-contained system that caused severe environmental hazards. The system does not use refrigerant but utilizes sound waves that propagate through the air via molecular collisions. The important element in the system is the secondary thermodynamic medium, stack which provides the phasing between heat transfer and pressure changes at acoustical frequencies. The objective of this research is to observe the cooling phenomenon in this system, which the temperature different above and below the stack are then compared if any changes happened in both sections.
Global Structure Analysis of a Class of Power System with Zero Characteristic Root
Authors: Cheng Xue Mei
Published: February 2012

The system with a zero characteristic root has had a more detailed discussion on global structure and the existing conditions of limit cycle. Through discussing the nature of the high-order singular point with two zero characteristic root of five order system , we will get the global structure of the system.
Review State of Geothermal Energy in Iran
Authors: Asadi Mohammad Reza , Moharrampour Mahdi , Ali Masoumeh Shir
Published: February 2012

International increasing of petroleum and living cost and population, environmental problems, diminishingly fossil sources and world trend to energy technology respect to environmental safety and renewable energies are some reasons for most countries to use and investigate on renewable energies. In this regard this paper presents the state of geothermal energy in Iran. The geothermal activities in Iran started by Ministry Energy of Iran in 1975, research and survey indicate that Iran has substantial geothermal potential, specifically in the Sabalan Sahand (NW-Iran) and Damavand (N-Iran) region that are considerate prospects for electric power generation and direct uses. The Electric Power Research Center (EPRC) and Renewable Energy Organization of Iran (SUNA) were established to justify priorities of above mentioned region. As a result: Meshkinshahr and Sarein area in Sabalan region were proposed for electric and direct use respectively. Three deep exploration wells and two shallow reinjection wells were drilled at the Meshkinshahr geothermal field during 2003/2004 following detailed geo-scientific surface surveys. A preliminary resource assessment confirms the presence of a medium grade geothermal resource with temperatures within the drilled area up to 2500C and whit at least 5 Km2 of commercially exploitable resource available. SUNA is now moving forward to construct and commission the first geothermal power development both in Iran and the Middle East.
Regenerated Antheraea pernyi Silk Fibroin Nanofiber Film
Authors: Mao Li , Liu Yu , Wu Xi Long , Lu Shen Zhou
Published: February 2012

Regenerated Antheraea Pernyi silk fibroin (ASF) solution was prepared by dissolving Antheraea Pernyi (A. pernyi) silk fiber in lithium thiocyanate solution. Atomic force microscopy (AFM) examination showed that there were many short nanofibers in regenerated ASF solution, which were made up of 10-20 nm nanospheres. In this paper, we discussed the formation mechanism of these nanofibers. The results of the surface tension showed that ASF had surface active and can significantly decline the surface tension of water from 73 mN/m to 51 mN/m. The hydrophobic side chains of ASF molecular would try to break away from water environment and thereby undergo self-assembly into nanospheres. And then, these nanospheres arrange into a short nanofiber. Then, the ASF nanofiber film was prepared by casting regenerated ASF solution blended with glycol. The structure of ASF was β-sheet and the film was water-insoluble. This blend film not only had excellent mechanical properties, but also can be biodegradated by enzyme in vitro. All of this indicated that this new regenerated ASF nanofiber film not only provided excellent biocompatibility, but also had large surface as extracellular matrix (ECM) to cell adhesion. The film made of nanofiber was similar to ECM on the nanoscale, which promoted cell migration and proliferation. In summary, it provided a great potential as a biological material.
Coupling Characteristics between Two Identical Microfibers or Nanofibers in Different Ambient Refractive Indices
Authors: Wu Ping Hui , Xu Dan Yang , Sui Cheng Hua
Published: February 2012

In this paper, we investigate theoretically the coupling characteristics of two identical microfibers or nanofibers (MNFs) with different ambient refractive indices. The results show that, compared with weakly coupled waveguides, coupled two MNFs can provide a much smaller coupling length without sacrificing high coupling efficiency. This feature is helpful for studying and developing microphotonic or nanophotonic devices with MNFs.
The Growth Mode of Vertically Aligned Carbon Nanofibers
Authors: Li Shuang Cui , Hao Chun Cheng
Published: February 2012

Very dense and vertically aligned carbon nanofibers were synthesized using a CVD at the temperature of 350°C. A high density of catalytic particles, which are necessary for the growth of vertically aligned nanofibers, were prepared by direct current sputtering method. In our experiment, the sphere-shaped copper nanoparticles were deposited on silicon substrate, and then these nanoparticles catalyzed the growth of carbon fibers using acetylene as carbon source in hydrogen atmosphere. The growth of vertically aligned nanofibers showed that each copper catalyst particle grow two linear carbon nanofibers, along the vertical direction respectively.
Physico-Chemical Properties and Characterization of CaO-Fe2O3-P2O5 Glass as a Bioactive Ceramic Material
Authors: Majhi M.R. , Kumar R. , Singh S.P. , Pyare R.
Published: February 2012

The Aim of this Work Is to Investigate Role of Iron in Calcium-Iron-Phosphate Bioglass. the Density, Compressive Strength, Tg Point and Leachability of Cations Were Measured. the Ph Behaviour of Simulated Body Fluid after Soaking Phosphate Glasses for Different Time Periods Were Also Studied and it Was Observed that Higher Phosphate Glasses Containing Lower Lime Possessed Better Bioactivity than Lower Phosphate Glasses Containing More Iron and Lime Contents. the DTA and FTIR Spectrometry of Glasses Were Performed. the Absorption Spectra Showed that Iron Was Present in the Glass only as Fe3+ Ion. the Leachability of Ca2+ and Fe3+ Ions from Glass Was due to Diffusion Control and P5+ Ion due to Network Break down of PO4 Tetrahedra. the DTA Peaks Were Broad. the FTIR Band around 1000 Cm-1 in Glass Was due to Asymmetric Stretching of O=P=O Linkage. the FTIR Absorption and Reflectance Spectrometry of the Glass Samples after SBF Treatment Had Confirmed the Deposition of Bone-Like Hydroxyl Carbonate Apatite Layer on the Glass Surfaces for their Bioactivity. the Bands Centred in between 2880-3425 Cm-1 Were due to Presence of OH Groups and Stretching Modes of H-O-H Vibration in Glasses. the Properties and Structure Relationship for Glasses Were Established and the Results Were Discussed.
Synthesis and Characterization of Bimetallic Fe/Co Nanocatalyst on CNTs for Fischer-Tropsch Reaction
Authors: Ali Sardar , Mohd Zabidi Noor Asmawati , Subbarao Duvvuri
Published: February 2012

Cobalt and iron are common catalysts used in the Fischer-Tropsch (FT) reaction. This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on carbon nanotubes (CNTs). The CNTs-supported nanocatalysts were synthesized by a wet impregnation method at various ratios of Fe:Co. The physicochemical properties of the samples were analyzed by H2-temperature programmed reduction (TPR), CO and H2-chemisorption analyses, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The effects of incorporation of Fe into Co on the physicochemical properties of Co/CNTs in terms of degree of reduction, CO and H2 chemisorptions and morphologies were investigated. TEM showed that metal nanoparticles were well dispersed on the external surface and inside the CNTs. For monometallic Co/CNTs and Fe/CNTs, the average metal particle size was 5±1 nm and 6±1 nm, respectively. For the bimetallic 70Co30Fe/CNTs nanocatalysts, the average particle size was found to be 4±1 nm. Metal particles attached to the outer walls were bigger than the ones inside the CNTs. H2-TPR analysis of Co/CNTs indicated two temperature regions at 330°C (low temperature) and 491°C (high temperature). The incorporation of iron into cobalt nanocatalysts of up to 30 % of the total metal loading enhanced the catalyst’s H2 and CO chemisorptions capacities and reducibility.
Parameter Fluctuations in Multiple Patterned Deca-nm Scaled CMOS Structures
Authors: Kallis Klaus T. , Horstmann John T. , Fiedler H.L.
Published: February 2012

Multiple Patterning Seems to Be One of the Most Promising Solutions for the Gap between the 193 Nm Immersion Lithography and the 13.5 Nm EUV Lithography for Industrial Manufacturing of Ultra Large Scaled Integrated CMOS Circuits [1]. the Used Techniques in this Paper Lead to an Excellent Homogeneity and Uniformity of the Channel Length and Width which Enables a Fundamental Statistical Analysis of the Electrical Transistor Parameters. the Process Flow Has Been Optimized to Minimize the Active Channel Area and to Achieve a Sufficient Yield for a Trustworthy Statistical Analysis. while the Channel Length Is Defined by a Single Deposition- and Etchback Technique the Active Area Is Defined by a Composition of Multiple Spacers that Lead to a Diffusion Stop Barrier. the Statistical Analysis of these Devices Shows Dramatically Increasing Fluctuations of the Threshold Voltage if the Device Dimensions Are Decreased.
Mg0.50Cu0.5-xNixFe2O4 Spinel Nanoferrites: Structural, Electrical, Magnetic and Y-K Angle Studies
Authors: Faraz Ahmad , Maqsood Asghari , Ahmad Nasir M. , Ur-Rehman Fazal , Ameer Shahid
Published: February 2012

Spinel Nanoferrites of Composition Mg0.50Cu0.5-XNixFe2O4 (0.00≤x≤0.50) Were Synthesized by Chemical Co-Precipitation Method. the Structural, Morphological and Magnetically Changes due to Varying Concentrations of Metal Ions of Cu and Ni in the Prepared Nanoferrites Were Studied. XRD Confirmed the Formation of Single Phase Spinel Ferrite with Crystalline Sizes in between 16-29 Nm, and the Lattice Parameter (a) Found to Decreases with Increase of Ni Concentration. Electrical Resistivity of the Prepared Nanoferrites with Varying Nickel and Copper Concentrations X Observed to Follow Arrhenius Relation and Also Exhibited the Semiconductor Behavior. the Magnetic Hysteresis Curves Clearly Indicate the Soft Nature of the Prepared Samples. Saturation Magnetization (Ms) Increases with Ni Content. This Effect Is Related to the Magnetic Moments of Ni+2 Ions. the Y-K Angles Increase with Increasing Ni Content, and Suggest a Non Collinearity Néel Type of Ordering of the Y-K Type. the Increase in the Y-K Angles Also Suggests the Increase in Triangular Spin Arrangements on B Sites, which Subsequently Lead to Increment in A-B Interactions.