-
Analysis on a Cast-Iron Pipe Applied to Protection of Underwater Cable
Issue:
Volume 5, Issue 3, May 2016
Pages:
119-124
Received:
16 May 2016
Published:
19 May 2016
Abstract: In this study, a protection-pipe system is developed for the protection of undersea electricity power cable laid along shoreline with medium deep water. The protection-pipes are made from ductile cast-iron alloys while the dimensions are designed corresponding to the diameter of balk electricity power cables. In order to know if the protection-pipe is strong enough to prevent the power cable from damages caused unnaturally, such as berthing anchoring from large size ships or towing operation from fishing boats, both analytical and experimental studies were carried out. Presented in this paper is an analytical study based on the material mechanics. A finite element analytical method was applied and the deformed shapes on the protection-pipe were studied. Along with the deformation, the corresponding stresses were also presented. In order to know the response of the protection-pipe subjected to an impact loading exerting on various parts of the pipe, several analysis for various loadings and boundary conditions were performed. It was found from the results of the analysis that the proposed protection-pipes are able to meet the requirements of TPC set for the electricity power cable laid under seawater.
Abstract: In this study, a protection-pipe system is developed for the protection of undersea electricity power cable laid along shoreline with medium deep water. The protection-pipes are made from ductile cast-iron alloys while the dimensions are designed corresponding to the diameter of balk electricity power cables. In order to know if the protection-pipe...
Show More
-
First-Principles Calculation for Thermodynamic Properties of LiD
Issue:
Volume 5, Issue 3, May 2016
Pages:
125-128
Received:
17 May 2016
Published:
19 May 2016
Abstract: In this paper, the lattice parameter and bulk modulus of LiD at different pressures and temperatures are calculated by using the density functional theory method within the generalized gradient approximation (GGA). Through the quasi-harmonic Debye model, the thermodynamic properties of the LiD are predicted. The dependences of the normalized primitive cell volume V/V0 on pressure P, the variation of the thermal expansion coefficient α with pressure P and temperature T, as well as the dependences pf the heat capacity Cv on pressure P and temperature T are obtained systematically in the ranges of 0-100GPa and 0-2000K.
Abstract: In this paper, the lattice parameter and bulk modulus of LiD at different pressures and temperatures are calculated by using the density functional theory method within the generalized gradient approximation (GGA). Through the quasi-harmonic Debye model, the thermodynamic properties of the LiD are predicted. The dependences of the normalized primit...
Show More
-
Study of Roll Forming Bending in Different Temperature
Issue:
Volume 5, Issue 3, May 2016
Pages:
129-135
Received:
23 May 2016
Published:
23 May 2016
Abstract: Flexible roll forming is a high efficiency sheet metal forming process for producing variable cross section profiles. Also spring-back is one of the most important problems in flexible roll forming process. Spring-back is severe during the unloading phase of bending and greatly affects the forming accuracy of the bending parts. In this paper, the spring-back of the flexible roll forming in different temperature have been studied using finite element analysis. The simulation is elaborated by using ABAQUS software linked to elastic–plastic modules which we developed taking into account of interactions between these fields. According to finite element analysis results, the bending after roll forming has been analyzed. Therefore, we can make the comparison of the spring-back and forming force under different temperature from the finite element analysis. A flexible roll forming setup was developed and some parameters in the simulation have been discussed. AZ31 magnesium alloys were used in the simulation and assumed the material is isotropic.
Abstract: Flexible roll forming is a high efficiency sheet metal forming process for producing variable cross section profiles. Also spring-back is one of the most important problems in flexible roll forming process. Spring-back is severe during the unloading phase of bending and greatly affects the forming accuracy of the bending parts. In this paper, the s...
Show More
-
Synthesis of Li[Li0.13Mn0.464Ni0.203Co0.203]O2 Cathode Material by Hydrothermal Treatment Method
Wang Meng,
Li Wei,
Yang Tao,
Wu Feng
Issue:
Volume 5, Issue 3, May 2016
Pages:
136-142
Received:
6 June 2016
Published:
7 June 2016
Abstract: The layered Li-rich Li[Li0.13Mn0.464Ni0.203Co0.203]O2 cathode material was successfully synthesized via a hydrothermal treatment on the precursor method. X-ray diffraction spectrometry (XRD) and scanning electron microscopy (SEM) were used to characterize the structure and micromorphology of the materials. Meanwhile, charge-discharge test and electrochemical impedance spectroscopy (EIS) were employed to explore its electrochemical performance. The results indicate that the Li[Li0.13Mn0.464Ni0.203Co0.203]O2 material possesses a layered α-NaFeO2 structure and exhibits excellent electrochemical performance. The initial discharge capacity is 235.9 mAh•g−1 in the voltage range of 2.0-4.8 V at 0.1 C. And it exhibits the capacity retention of 94.1% after 50 cycles. The hydrothermal treatment not only shortens the calcination time, but also can greatly improve the electrochemical performance of the material.
Abstract: The layered Li-rich Li[Li0.13Mn0.464Ni0.203Co0.203]O2 cathode material was successfully synthesized via a hydrothermal treatment on the precursor method. X-ray diffraction spectrometry (XRD) and scanning electron microscopy (SEM) were used to characterize the structure and micromorphology of the materials. Meanwhile, charge-discharge test and elect...
Show More
-
Study of Thermal Properties of Some Selected Tropical Hard Wood Species
Samuel Aggrey-Smith,
Kwasi Preko,
Francis Wilson Owusu
Issue:
Volume 5, Issue 3, May 2016
Pages:
143-150
Received:
15 March 2016
Accepted:
25 March 2016
Published:
17 June 2016
Abstract: The uses of wood and wood-based materials in everyday life ranging from domestic to industrial purposes have called for renewed updating of the information and knowledge on various thermal properties of the materials at various stages and classifications. This paper investigates the thermal properties (specific heat capacity and thermal conductivity) of some selected tropical hard wood species using the method of mixtures and the Lee’s Disk method respectively. The results show that the thermal conductivity of the selected wood species fall within the general range of 0.1-0.8 W/mK for tropical wood materials, with Celtis mildraedii having the least thermal conductivity of 0.08W/mk and Strombosia glaucescens the highest value of 0.392 W/mK. The specific heat capacity was highest for Holorrhena floribunda (1.97 J/g.K) and the lowest for Pterygota macrocarpa (1.01 J/g.K). These results can be used for testing the validity and efficiency of hard woods used for domestic and industrial applications.
Abstract: The uses of wood and wood-based materials in everyday life ranging from domestic to industrial purposes have called for renewed updating of the information and knowledge on various thermal properties of the materials at various stages and classifications. This paper investigates the thermal properties (specific heat capacity and thermal conductivit...
Show More
-
Molecular Dynamics Simulation of Tensile Behavior on Ceramic Particles Reinforced Aluminum Matrix Nanocomposites
Heng Gu,
Jiao Jiao Wang,
Zhongwei Li
Issue:
Volume 5, Issue 3, May 2016
Pages:
151-159
Received:
7 July 2016
Published:
7 July 2016
Abstract: The mechanical properties and interfacial structures for aluminum matrix composites reinforced by nanometer-sized SiC-β particles has been studied using molecular dynamics (MD) simulation. The modified embedded atom methods, was implemented to describe the atomic interactions. The molecular model undergoes an annealing MD simulation from 300 K to 1000 K to reach its minimum energy point. Tensile tests were performed with periodic boundary conditions. The stress-strain relationship has been studied and elastic constants were predicted as well. The results were compared with those given by continuum-based finite element analysis (FEA) together with the experimental data available in the literatures. It showed that both the elastic modulus and yield stress were further strengthened due to the presence of the nano-particles. Also, it was found that the existing SiC nano-particles have an effect on the initial arrangement of Al atoms in such a manner: Al atoms were inclined to aggregate around the particle surface. Aluminum concentrations were also observed inside the SiC particles close to the surface. The depth of hybridization is uniform and planar.
Abstract: The mechanical properties and interfacial structures for aluminum matrix composites reinforced by nanometer-sized SiC-β particles has been studied using molecular dynamics (MD) simulation. The modified embedded atom methods, was implemented to describe the atomic interactions. The molecular model undergoes an annealing MD simulation from 300 K to 1...
Show More
-
Molecularly Imprinted Microspheres for the Adsorption of Chlorpyrifos
Wei Yao,
Shanyu Wang,
Baofeng Xu,
Hong Yin,
Zhixian Gao
Issue:
Volume 5, Issue 3, May 2016
Pages:
160-163
Received:
14 June 2016
Accepted:
28 June 2016
Published:
13 July 2016
Abstract: To obtain the desired specific adsorbents for chlorpyrifos to enrichment, separation and analysis of trace pesticides residue, molecularly imprinted polymer microspheres were prepared by precipitation polymerization using chlorpyrifos and methacylic acid (MAA) as template and functional monomer respectively. Computer simulation was employed to demonstrate the mechanism of the interaction between chlorpyrifos and MAA. The adsorption properties of chlorpyrifos, in acetonitrile for imprinted microspheres were evaluated by equilibrium rebinding experiments. Scatchard plot analysis revealed that there was a class of binding sites populated in the molecularly imprinted polymers (MIPs). The specificity of the imprinted microspheres was investigated by binding analysis using chlorpyrifos and related organophosphate pesticides. The results indicated that the obtained imprinted microspheres showed a good selectivity for chlorpyrifos.
Abstract: To obtain the desired specific adsorbents for chlorpyrifos to enrichment, separation and analysis of trace pesticides residue, molecularly imprinted polymer microspheres were prepared by precipitation polymerization using chlorpyrifos and methacylic acid (MAA) as template and functional monomer respectively. Computer simulation was employed to demo...
Show More
-
The Preparation of Silicon Nanowires Using Metal-Assisted Chemical Etching
Lu Xiaoci,
Li Changqing,
Ding Gangjian
Issue:
Volume 5, Issue 3, May 2016
Pages:
164-168
Received:
14 July 2016
Published:
15 July 2016
Abstract: The preparation of silicon nanowires by metal catalytic chemical etching has the advantages of low cost and simple operation. This study attempts to use a silver-assisted chemical etching to prepare silicon nanowires. In the process of experiment we change the corrosive liquid concentration of corrosion and corrosion time to compare these factors on the surface topography of silicon nanowires in the preparation. The experimental results were observed by optical microscope and electron microscope. The experiment shows that in the process of etching, etching time of CLSM has had a huge impact, if etching time is short, the sample cannot generate silicon nanowires, while a long etching time will cause silicon erode up, finally dissolved in the etching liquid. The wafer surface surface morphology of honeycomb like, and the result shows that when the corrosive liquid concentration is 0.02mol/L and the corrosive time is four works better, formed the length 100-200nm and the line diameter 100μm and more uniform silicon nanowires.
Abstract: The preparation of silicon nanowires by metal catalytic chemical etching has the advantages of low cost and simple operation. This study attempts to use a silver-assisted chemical etching to prepare silicon nanowires. In the process of experiment we change the corrosive liquid concentration of corrosion and corrosion time to compare these factors o...
Show More
-
Characterization and Modeling of a Highly Reliable ONO Antifuse for High-Performance FPGA and PROM
Liu Guozhu,
Wu Jianwei,
Yu Zongguang,
Hong Genshen,
Zheng Ruocheng,
Liu Baiqin,
Wu Suzhen,
Du Tao
Issue:
Volume 5, Issue 3, May 2016
Pages:
169-177
Received:
18 July 2016
Published:
19 July 2016
Abstract: The characteristics and reliability of ONO (oxide-nitride-oxide) anti-fuse devices prepared basing on 0.6µm SOI CMOS process have been studied experimentally and theoretically. The intrinsic principles of ONO dielectric breakdown were investigated with tunneling and emission models. It has been found that the conduction mechanisms of ONO dielectrics under high electric field (>10MV/cm) mainly obeys Fowler-Nordheim (F-N) tunneling and Poole-Frenkel (P-F) emission and Ohmic transport models. Meanwhile, the nitrogen depth distribution and the composition of the ONO stack films have been accurately determined using SIMS and EDX, respectively. The results indicate that the nitrogen concentration of interface between tunneling oxide and N+ sub-silicon is higher than that of interface between top oxide and N+ poly-silicon, which can contribute to prove the difference of top and bottom electrode interface barriers according to energy band diagrams of ONO anti-fuse devices. Besides, it is also found that the average breakdown voltage of ONO anti-fuse arrays and that of distribution decrease with increasing the number of anti-fuse cells, and the result is attributed to traps density of various areas. Moreover, the programming resistance of ONO anti-fuse cells and programming circuits decreases with increasing programming current, and the programming resistance of ONO anti-fuse cells can reach less than 200 ohm/cont when programming current is above 5mA. And the life of unprogrammed ONO anti-fuse devices can reach more than 40 years under an electric stress of 5.5v at the temperature from 25°C to 125°C. So, it can be concluded that the characteristics and reliability of the proposed ONO anti-fuse elements are suitable for applications in FPGA and PROM.
Abstract: The characteristics and reliability of ONO (oxide-nitride-oxide) anti-fuse devices prepared basing on 0.6µm SOI CMOS process have been studied experimentally and theoretically. The intrinsic principles of ONO dielectric breakdown were investigated with tunneling and emission models. It has been found that the conduction mechanisms of ONO dielectric...
Show More
