bluuebunny/crossref_metadata_2025 huggingface dataset:
Microscopic Analysis Following Bending of Roving Type Composite Material
Authors: Cotoros Diana , Stanciu Anca Elena , Baritz Mihaela , Cristea Luciana
Published: May 2015

Microscopic analysis represents a non-invasive method for both intermediate and final control. It can be performed without very expensive and complicated equipment and may be available for all kind of composite material parts meant to be used in various fields, starting with industry and finishing with medicine and sports. Using microscopic analysis allows obtaining information about the structure of the material, aspect of the ruptures after the specimen’s failure, thus being able to decide whether the material is suitable for the intended purpose or some changes in its structure, composition or manufacturing technique is required.
Experimental Research on Surface Roughness in Turning of E355 Alloy Steel on CNC Machine Tool
Authors: Furdui Filip , Cîrstoiu Carmen Adriana
Published: May 2015

This work suggests some possibilities of determination of cutting conditions for the cutting process.The most important factors affecting the surface roughness of machined sourfaces are the cutting parameters. It was shown in the paper the influence of finishing cutting regimes, for a given geometry of insert, on surface roughness of turned surfaces on CNC lathe, with higher cutting speeds than those used on conventional machine tools and with very small advances and cutting depths, thus explaining certain phenomena that occur in the cutting process.
Some Considerations Concerning the Analysis of Drilling Process
Authors: Manole Vasile , Munteanu Adriana , Coteaţă Margareta , Slătineanu Laurenţiu
Published: May 2015

The analysis of the drilling process addressed in this paper aims highlighting the factors able to exert influence on parameters of technological interest corresponding to such a process. There were applied the method of systemic analysis, Ishikawa diagram, SWOT analysis. The significance of the drilling tool active zone geometry within the drilling process and, in the tests for evaluation of the machinability by drilling was emphasized. With this aim in view, preliminary tests of using a specialized equipment for sharpening the small diameter drills were initiated.
Finite Element Analysis to Improve the Accuracy of ABS Plastic Parts Made by Desktop 3D Printing Method
Authors: Păcurar Răzvan , Păcurar Ancuţa , Popişter Florin , Popişter Anca
Published: May 2015

The development of low-cost desktop versions of three-dimensional (3D) printers has made these devices widely accessible for rapid prototyping and small-scale manufacturing in home and office settings. Many desktop 3D printers rely fused deposition modeling process, that it is based on heated thermoplastic filiform material that it is extrused through a nozzle and deposited afterwards onto a heated building platform. The extruding accuracy in part fabrication is subject to transmission machinery and filament diameter on one hand and the technological parameters that are used in the manufacturing process (raster angle, tool path, slice thickness, build orientation, deposition speed, building temperature, etc.) on the other hand. The presented work try to investigate by using the finite element method, how the building temperature in close connection with the material characteristics is influencing the accuracy of a test part that has been designed in order to callibrate an Desktop 3D Printer machine that has been originally designed and produced at the Technical University of Cluj-Napoca (TUC-N).
Use of Taguchi Method and Grey Relational Analysis for Optimizing a Ram Electrical Discharge Machining Process
Authors: Slătineanu Laurenţiu , Dodun Oana , Coteaţă Margareta , Mircescu Ciprian , Beşliu Irina , Radovanovic Miroslav
Published: May 2015

There are various factors able to exert influence on the results of electrical discharge machining process. If there are many output factors of the machining process, one can formulate a problem of multicriterial optimization. It is necessary to find adequate values for the input factors so that the output factors have optimized values. The paper presents the results of a research aiming to optimize the material removal rate and the tool electrode wear rate, in the case of ram electrical discharge machining process. As input factors, one used the pulse on time, pulse off time and average peak current intensity. The Taguchi method was applied, in association with the Grey relational analysis. In this way, combinations of values corresponding to the input factors were determined, in order to obtain optimal results for the process output factors.
Experimental Research on Wear and Thermal Deformation for Shaft Gauge
Authors: Orzan Alexandru , Buzatu Constantin
Published: May 2015

Based on multiple experimental researches the paper presents graphics and mathematical models obtained by data processing using modern software of wear dependence and cumulate thermal deformations according to the number of controlled number of pieces and dimension of the gauge. Taking into consideration the obtained results, the paper presents conclusions and recommendations over these factors of influence (wear and thermal deformation) over the accuracy quality control of the products, recommendations design and optimal usage of shaft gauges.
Research Regarding Adaptive Design of Gear Pumps Used for Polymeric Products Engineering
Authors: OPRAN Constantin Gheorghe , Pricop Mircea , Teodoru Constantin
Published: May 2015

This paper present the results of the researches regarding innovative and adaptive design of gear pumps for engineering of polymeric products with application in production of injection molding machine. It shows the description of gear pump with innovative design and double gear pump – innovative design, highlighting innovative design feature through constructive adaptation depending on requirements, having (30 – 40) % smaller at the axial size, compared to the classic pumps. They highlight the competitive advantages of innovative pumps with superior technological parameters. The paper also shows numerical simulation of technological parameters for pumps in innovative and adaptive variant proving the correctness and the advantages of new variants. Using the innovative variant allows the development a family of gear pumps, single and double, extremely compact, robust, reliable and with low manufacturing costs.
Assessing Bias and Linearity of a Measurement System
Authors: Simion Carmen
Published: May 2015

Product and process conformance are determined by measurements that are taken by a measurement system. A clear understanding of the results of any measurement system requires an understanding of the possible errors within this system. Measurement system errors can be classified into two categories: accuracy and precision. The accuracy of a measurement system is usually broken into three components: bias, linearity and stability and the precision into repeatability and reproducibility. There are a number of procedures which are used, in the automotive and other industries to assess these statistical properties of any measurement system. Usually, companies use repeatability & reproducibility procedures but, according to a measurement systems analysis study, these may not be enough for a company that wants to meet current worldwide quality system standards. Lack of measurement equipment bias and linearity generally is not as predominant error as repeatability and reproducibility, nevertheless, it should be identified because each person that have direct responsibility for measurement evaluation, selection, and control must hand on experience in how to produce a bias and linearity study. A bias study examines the difference between the observed average of the measurements and a reference value. It answers the question “How accurate is my measurement equipment when compared to a master value ?”. A linearity study tells one how accurate the measurements are through the expected range of the measurements. It answers the question “Does my measurement equipment have the same accuracy for all sizes of objects being measured ?”. Determining the bias and linearity of the measuring equipments and understanding their impact on the measured values will contribute to the effectiveness of the measurement system. In this context, conception and method of bias and linearity analysis of measurement systems are introduced in this paper followed by a real world application done in a major local automotive company. The analysis had ensured consistency of measurements and provided evidence that the measurement system is functioning properly. Minitab software was used to study bias and linearity of the analyzed measurement system.
Thermal Response for a Reinforced Concrete Slab Analyzed with Active Infrared Thermography and Comsol Multiphysics
Authors: Dragan Razvan Gabriel , Rosca Ileana Constanta , Cazangiu Diana , Leonte Alexandru Stefan
Published: May 2015

This paper presents a non-destructive technique (NDT) using active infrared thermography and FEM analyses with Comsol Multiphysics software applied for thermal distribution detection through reinforced concrete. For this work a reinforced concrete slab was created having a parallelepiped shape, the length and the width of 400 mm and the thickness of 50 mm. The concrete slab was reinforced using a rebar mesh of 18 mm diameter. The experimental installation consisted of an electrical heating source and a steel frame for fixing the slab and for the thermal distribution analyses an infrared camera was used. The same type of material and conditions like in the laboratory was used for the FEM analyses in Comsol Multiphysiscs to compare with the experimental part. A concrete slab without steel was used to determine the difference between the simple concrete and reinforced concrete in the heat transfer process.
Economic Performance Assessment Model for Industrial Systems: A Case Study
Authors: Fechete Flavia , Nedelcu Anișor
Published: May 2015

Performance
a
nalysis of an organization has a
major
role in setting t
he strategy followed especially
during the financial crisis. In what follows we performed
a
financial analysis, based on data from the balance sheet and profit and loss account of a company that produces and sells
crystal
sugar, using a system
of indicators that are relevant. Using the results of this economic analysis we
can draw certain conclusions according to which can forecast future developments. I tried to use a number of indicators of a system that defines, in the end, a model for analyzing the economic performance of a compa
ny. The research focused on the
application of the diagnostic performance of agreed financial data recorded by that company.
Quality Management Approach in Qualifications Framework Implementation in Industrial Engineering
Authors: Rohan Rodica , Ionescu Nicolae
Published: May 2015

Currently in Romania it has been implemented the European Qualifications Framework (EQF) and its sustainability has become an impending need. In this paper, the authors propose an integrating structure, which involves a relatively large number of organizations for the sustainability of the National Qualifications Framework (CNC), while also providing quality assurance in higher education. Using quality management principles and their implementation stages as generic conceptual solutions, there have been established the specific conceptual solutions for the conceptual design of a system which the authors have called the System of Implementation and Sustainability of the National Qualifications Framework in Higher Education (SIS - CNCIS). It was then prepared the detailed design of the SIS-CNCIS for the particular case of implementation in Industrial Engineering.
Contributions to Predict the Malfunction Probability of the Human-Machine-Environment System, Using Artificial Neural Networks
Authors: Anghel Daniel Constantin , Belu Nadia
Published: May 2015

This paper presents the application of Artificial Neural Networks to predict the malfunction probability of the human-machine-environment system, in order to provide some guidance to designers of manufacturing processes. Artificial Neural Networks excel in gathering difficult non-linear relationships between the inputs and outputs of a system. We used, in this work, a feed forward neural network in order to predict the malfunction probability. The neural network is simulated with Matlab. The design experiment presented in this paper was realized at University of Pitesti, at the Faculty of Mechanics and Technology, Technology and Management Department.
Optimizing Assembly Line Production through Line Balancing: A Case Study
Authors: Saptari Adi , Leau Jia Xin , Nor Akramin M.
Published: May 2015

In Line Balancing principles, the total workload in the assembly process is divided as evenly as possible among the workstations, without violating the sequences and relations in the assembly operations. Line balancing is important in an assembly system as it balances the line and increases the efficiency, as well as the productivity of a system. A case study was conducted in the assembly line of an electrical accessories manufacturer in Malaysia. The cycle time for each station was recorded, and the standard cycle time was estimated. The productivity, as well as the efficiency of the current assembly line, were studied. In terms of the productivity, the performance of the current systems was 500 units/worker/day, while the expected productivity was 600 units/worker/day. An assembly line setting was proposed based on the Line Balancing Method; the productivity for the proposed line increased to 671 units/worker/day, or in rough additional increase around 34%.
Improvement of Overall Equipment Effectiveness (OEE) through Implementation of Total Productive Maintenance (TPM) in Manufacturing Industries
Authors: Kasim Nazrul Idzham , Musa Mohd Azam , Razali Akhtar Razul , Mohamad Noor Noraishah , Wan Saidin Wan Ahmad Najmuddin
Published: May 2015

Today competitive manufacturing requires innovative approaches in the production management, as well as for customer satisfaction. Production management requires an effective and efficient maintenance management system. One approach to improve the performance of the maintenance system is through the implementation of Total Productive Maintenance (TPM). The key performance index to measure the effectiveness of TPM implementation is Overall Equipment Effectiveness (OEE). The TPM activities will eliminate equipment losses related to availability, performance rate, and quality rate. Hence, the TPM implementation will increase the OEE value. This paper outlines the theories of TPM and OEE. The paper also presents the studies carried out by different authors to show the improvement of OEE through implementation of TPM in manufacturing, such as electronic industry, steel manufacturer, as well as locomotive components manufacturer.
Development of System Identification for Piezoelectric Patch Actuator
Authors: Maslan Mohd Nazmin , Jamaludin Z. , Rahman Muhamad Arfauz A. , Abdullah Lokman , Abd Latib Mohd Lutfan , Karjanto Juffrizal , Mailah Musa
Published: May 2015

This paper presents the development of the system identification (SI) for the highly nonlinear piezoelectric patch actuator. The transfer function is determined by using the nonlinear least square (NLS) method after the direct measurements of input-output data are taken from the actuator that is installed on a well-equipped platform. The results were validated to ensure that the transfer function derived fits well with the experimental output.
Optimization of Milling Parameter for Untreated and Heat Treated Polyetheretherketones (PEEK) Biomaterials
Authors: Izamshah Raja , Lung A. Yu , Mohamad Effendi , Azam Mohd Asyadi , Amri Mohd , Liew P.J. , Sanusi Mohd
Published: May 2015

Polyetheretherketones (PEEK) have been widely used as biomaterials for trauma, orthopedics and spinal implants. However, machining of this material poses several challenges such as rough machined surface which can affect the implant functional application. This research attempts to optimize the machining parameter (cutting speed, feed rate and depth of cut) for effectively machining Polyetheretherketones (PEEK) implant material using carbide cutting tools. Apart from optimizing machining parameters, effects of annealing condition on PEEK towards surface qualities are discuss. Response Surface Methodology (RSM) technique was used to evaluate the effects of the parameters and their interaction towards the ability of the optimum conditions. Based on the analysis results, the optimal machining parameter to obtain the smallest surface roughness values were by using spindle speed of 5754 rpm, feed rate of 0.026 mm/tooth and 5.11 mm depth of cut for un-annealed PEEK. As for the annealed PEEK to get the smallest surface roughness values were by using spindle speed of 5865 rpm, feed rate of 0.025 mm/tooth and 2 mm depth of cut.
Electrophoretic Deposition and Heat Treatment of Steel-Supported PVDF-Graphite Composite Film
Authors: Lau Kok Tee , Ab Razak Mohd Hafrez Razi , Kok Swee Leong , Zaimi Muhammad , Abd Rashid Mohd Warikh , Mohamad Noraiham , Azam Mohd Asyadi
Published: May 2015

Polymeric poly (vinyliden fluoride) (PVDF) is nontoxic. It possesses a better mechanical flexibility and requires a lower synthesis temperature, as compared to the piezoceramic counterparts. In order to achieve a competitive advantage against the current piezoelectric sensor, graphite could replace a more expensive silver-palladium as the electrodes for the piezoelectric PVDF. This paper reports the preliminary results on the synthesis of steel-supported graphite-PVDF/PVDF/graphite-PVDF composite films using the two-step process, consisted of the electrophoretic deposition (EPD) and heat treatment. The composite films were characterized by means of the optical microscopy, scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. The heat treated graphite-PVDF electrode deposited by EPD provides adequate mechanical strength for the subsequent depositions of pure PVDF layer and the second layer of graphite-PVDF composite electrode. However, the final heat treatment stage did not eliminate the fine and large cracks of the composite film, which might be attributed to high residue stresses and weak bonding between graphite and PVDF particles in the post-heat treated composite films. Nevertheless, the increase in final heat treatment temperature of the composite film at Stage 3 improved the graphite and PVDF grain alignment, as well as its crystallinity.
Development of Green Composite: Pineapple Leaf Fibers (PALF) Reinforced Polylactide (PLA)
Authors: Munawar Rose Farahiyan , Jamil Nurul Hayati , Shahril Mohd Khairul , Skh Abdul Rahim Skh Muhammad , Zainal Abidin Muhammad Zaimi , Azam Mohd Asyadi , Lau Kok Tee
Published: May 2015

Green composite material has become the most desired material to replace polymer composites made from fossil oil. Besides having advantages over its biodegradability and quality performances, the material sources are abundant and renewable. Therefore, this research focused on developing green composite which is derived from a combination of pineapple leaf fibers (PALF) and Polylactide (PLA). PALF is extracted from pineapple leaves which are easily found during harvesting pineapple plantation. In order to study the influences of different fibres characterization, the fibres were extracted from different types of pineapple available in Malaysia, namely Moris Gajah, Jasopine, Maspine, and N36. The main objective of this study was to investigate the physical and mechanical properties of this green composite. The physical testing was carried out to determine water absorption while the tensile and bending tests were conducted for mechanical testing. For the purpose of comparing the material properties, PALF reinforced polypropelene (PP) was developed too. Based on the result, Jasopine fibre shows the highest tensile and flexural strength for the combination of both polymers in comparison to the other types of PALF.
The Measures of Performance for World Class Manufacturing Practices: A Critical Review
Authors: Sukarma Lukman , Azmi Hafizah
Published: May 2015

As a continuation of the previous paper by the same authors, this article presents a critical analysis on how companies practicing world class manufacturing (WCM) have to modify their ways of measuring performance in their efforts to attain manufacturing excellence. In doing so, implications of implementing WCM methods in measuring company performance are elaborated. While business performance depicts a company's ability to satisfy customers' needs, hence customers mostly perceive their measurement; manufacturing performances can be used as yardsticks to assess the effectiveness of its resources to satisfy the customer. This paper proposes 15 manufacturing performance as key performance indicators for a company pursuing WCM.
Characterization on Piezoelectric Cantilever for its Linear Response at Low Frequency for Measuring Acceleration Level of Vibration
Authors: Bong Yu Jing , Kok Swee Leong
Published: May 2015

The output response of the piezoelectric cantilever has excellent linearity over a very wide dynamic range. This paper demonstrates the potential of piezoelectric cantilever to be a self-powered accelerometer. Three different-sized piezoelectric cantilevers were tested under a vibration source at 50 Hz, 100 Hz, and 150 Hz. It is proven that the piezoelectric cantilevers can be used as an accelerometer since the output voltage generated by the cantilever is linear and proportional to the vibration acceleration level far before reaching its resonance. Three piezoelectric cantilevers with similar length of 28.6 mm, but different width of 3.2 mm, 6.3 mm and 12.7 mm were used in the experiment in order to observe the linearity of the output voltage from different-sized piezoelectric cantilevers with the same resonance frequency. The length of piezoelectric may affect the resonance frequency of the cantilever, while the width of the piezoelectric will not. Hence, cantilevers with different width are chosen as the subject of the experiment. The linearity of the experiment results show the maximum error percentage obtained is between 5 to 15% when excited at a vibration magnitude in the range of 1 to 5-g.
Concurrent Engineering in Natural Fibre Composite Product Development
Authors: Sapuan S.M.
Published: May 2015

In this paper a study of concurrent engineering in the development of product from natural fibre composites is presented. As far as the natural fibre composites are concerned, concurrent engineering is strongly linked to the design for sustainability because the design of natural fibre composite products fulfils the requirement of the design for sustainability, i.e. design for well-being of future generation. A study of the development of food packaging materials has been conducted. This study involved the development of sugar palm starch bio-polymer, selection of the most suitable bio-polymer, development of sugar palm fibre reinforced bio-polymer composites and design for food packaging of sugar palm fibre, specifically the sugar palm polymer composites.
Fabrication of Convex Plate-Shaped Micro Tool Electrode and its Application in Micro Hole Machining by ECM
Authors: He Zhi Wei , Wang Ming Huan , Zhang Li , Peng Wei
Published: May 2015

A method of fabricating convex plate-shaped micro electrode was proposed based on the electrochemical etching principle. The square sectional electrodes were prepared in advanced using wire-EDM, The micro cylindrical electrode was fabricated firstly by using the eletrochechemical etching method. Then the top end was insulated to protect it from etching. Then the convex plate-shaped micro electrode was obtained in subsequent etching. Comparative experiments in drilling micro-hole in stainless steel with the thickness of 1mm were done by using the cylindrical and convex plate-shaped micro electrode. Results shows that the better locality, smaller side-gap and hole taper could be obtain by using convex plate-shaped micro electrode.
Effect of Undercut on the Characterization of the Mechanical Properties of Silicon Nanocantilevers with Dynamic and Static Test
Authors: Zhang Jia Hong , Gu Fang , Zhang Xian Ling , Li Min , Ge Yi Xian , Mao Xiao Li
Published: May 2015

The elastic mechanical properties of silicon nanocantilevers are of prime importance in biotechnology and nanoelectromechanical system (NEMS) applications. In order to make these applications reliable, the exact evaluation of the effect of the undercut on the mechanical properties of silicon nanocantilevers is essential and critical. In this paper, a numerical-experimental method for determining the effect of the undercut on resonant frequencies and Young’s modulus of silicon nanocantilevers is proposed by combining finite element (FE) analysis and dynamic frequency response tests by using laser Doppler vibrometer (LDV) as well as static force-displacement curve test by using an atomic force microscope (AFM). Silicon nanocantilevers test structures are fabricated from silicon-on-insulator (SOI) wafers by using the standard complementary metal-oxide-semiconductor (CMOS) lithography process and anisotropic wet-etch release process based on the critical point drying, which inevitably generating the undercut of the nanocantilever clamping. Combining with three-dimensional FE numerical simulations incorporating the geometric undercut, the dynamic resonance tests demonstrate that the undercut obviously reduces resonant frequencies of nanocantilevers due to the fact that the undercut effectively increases the nanocantilever length by a correct value ΔL. According to a least-square fit expression including ΔL, we extract Young’s modulus from the measured resonance frequency versus the effective length dependency and find that Young’s modulus of a silicon nanocantilever with 200-nm thickness is close to that of bulk silicon. However, when we do not consider the undercut ΔL, the obtained Young's modulus is decreased 39.3%. Based on the linear force-displacement response of 12μm long and 200nm thick silicon nanocantilever obtained by using AFM, our extracted Young’s modulus of the [110] nanocantilever with and without undercut is 169.1GPa and 133.0GPa, respectively. This error reaches 21.3%. Our work reveals that the effect of the undercut on the characterization of the mechanical properties of nanocantilevers with dynamic and static test must be carefully considered.
A Compact Infrared Gas Sensor Based on an Asymmetry Gas Cavity
Authors: Ming An Jie , Ren Yao Hui , Zhang Yu , Zhang Le , Zhang Wen Bo , Tan Zhen Xin , Ou Wen , Tan Qiu Lin , Mao Hai Yang , Xiong Ji Jun , Chen Da Peng
Published: May 2015

Many gas molecules absorb electromagnetic radiation at characteristic wavelengths in the infrared region. This absorption can be used to identify defined substances like CO2, ammoniac, and so far. This study presents a comparative analysis of parameters of infrared radiation source and detector hardware that are most important for the creation of portable optical nondispersive infrared (NDIR) gas sensors. One of the central issues in the design of this kind of sensors is the geometry of the sensor cell. In this paper we investigate an asymmetry sensor cavity and predict the performance using Tracepro software. Then, the CO2 sensor is made and tested.
The Design of an Interface Circuit for Micro-Electrostatic Vibration Energy Harvesters and Super-Capacitor
Authors: Chen Si , Lu Ying Xian , Wang Xiao Hong
Published: May 2015

This paper presents the design of an interface circuit for storing power generated by low-frequency vibration based electrostatic energy harvesters. The circuit includes a structure of negative voltage converter with an active diode to minimize the forward voltage drop, and it also includes a boost-buck converter to accommodate a wide input voltage. The circuit has also been optimized to perform resistive matching. The maximum voltage of the capacitor in charging reaches about 1.83 V in simulation.
Fabrication of Aluminum Nitride Films by Reactive Pulse DC Magnetron Sputtering for Vibration Energy Harvester
Authors: Shang Zheng Guo , Li Dong Ling , Wang Sheng Qiang
Published: May 2015

Aluminum nitride (AlN) film as a piezoelectric material has been used widely, particularly in vibration energy harvester due to its unique and enhanced properties such as high temperature resistance and compatibility with CMOS processes. In this work, AlN film with (002) preferred orientation was prepared on silicon wafers by pulse DC reactive magnetron sputtering (RMS), and the properties such as peak intensity, full width at half maximum (FWHM) and surface morphology were investigated by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The preferred orientation was found to be sensitive to deposition conditions such as gas flow rate, power, bottom electrodes materials and substrates temperature. The results shows that the intensity was 1.1×105 counts, the FWHM was 1.9owhen the temperature was 260°C. The film was used to fabricate the vibrated energy harvester successful and the power density reached about 3000uW/cm3 at the vibration frequency under 1g acceleration.
Facile Fabrication of Super-Hydrophobic Surfaces by Spray PTFE
Authors: Wang Yang , Zhang Hai Feng , Liu Xiao Wei
Published: May 2015

We have developed a combination of electro –deposition and spraying methods to prepare water-repellent tin oxide/ polytetrafluoroethylene(SnO2/PTFE) coating. The coating has a high water contact angle. The resulting porous and lowest surface energy hydrophobic groups (－CF3) has a water contact angle of 165° and a sliding angle of 7°, showing super-hydrophobic property. The coating with good adhesion on substrates and the long-term stability can be fabricated on various metal substrates.
Electrohydrodynamic Atomization Deposition of Fuel Cell Catalyst-Coated Membrane with Structure and Material Gradient Variation
Authors: Wang Da Zhi , Zha Wen , Zhu Xiao Hu , Li Yang , Liang Jun Sheng , Ren Tong Qun , Luo Yi , Wang Xiao Dong , Liu Chong
Published: May 2015

A catalyst-coated membrane (CCM) with structure and material gradient variation was deposited layer-by-layer (LbL) using electrohydrodynamic atomization (EHDA) deposition. This CCM contained 7 layers which is C cathode diffusion layer, Pt/C-C cathode transition layer, Pt/C cathode catalyst layer, Nafion membrane, Pt-Ru/C anode catalyst layer, Pt-Ru/C-C anode transition layer and C anode diffusion layer. The cathode and anode side were named as cathode and anode catalyst-diffusion layers, respectively. It was observed that the cathode and anode catalyst-diffusion layers presented the dendritic structure. Within the cathode and anode catalyst-diffusion layers, the Pt/C-C and Pt-Ru/C-C transition layer was more porous compared to the C layer, Pt/C layer and Pt-Ru/C layer. It was also shown that the EHDA LbL deposited CCM still presented close-packed structure after life test.
To Improve Micro-Planar-Magnetic Generator Performance Based on Addition of Magnetic Material
Authors: Du Lin , Shi Geng Chen , Zhao Jing Jing
Published: May 2015

By finite element simulation and experiment, this paper compares the performance of generators with magnetic material to generators without magnetic material (Fe) in its coil and analyzes the reason why there is difference between simulation results and experimental results. Experimental results present that under the same rotational speed, output voltage improves 60% with the addition of magnetic material in coil compared to generator without magnetic material in coil. We further discuss the feasibility to add magnetic material in coil, present the existed problems and improvement methods.
Electrospun SnO2-Graphene Composite Nanofibers as High Performance Anode for Lithium Ion Batteries
Authors: Wu Yu Ling , Lin Jie , Wang Jian Yan , Guo Hang
Published: May 2015

A promising anode material for lithium ion batteries is reported in this paper. It is one-dimensional SnO2−graphene composite nanofibers (SnO2−G nanofibers) fabricated by using electrospinning technique. In the study, X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to characterize its structural and morphological properties. Samples with different ratio of SnO2 to graphene (wt%) are prepared to investigate its electrochemical performance. Galvanostatic charge/discharge tests reveals that Li-insertion/extraction is carried out through a two-phase reaction mechanism that is supported by galvanostatic charge−discharge profiles. It is found that the optimal proportion of SnO2 to graphene is 8:1 (wt%) for the electrospun composite materials. Furthermore, micro thin film batteries have been fabricated and tested. The results show that initial discharge capacity is 301.86 mA h g−1 at current density of 50 μA g−1, and battery can retain 63.3% of reversible capacity after 300 cycles, which is 5 times higher than bare SnO2.
Large-Scale Synthesis and Microwave Absorption Properties of CoFe2O4/ Co0.4Zn0.6Fe2O4 Hollow Nanospheres
Authors: Ren Qing Guo , Qiao Xiao Jing , Li Yan , Sun Zhi Gang , Guo Xiao Dang , Zhang Shuai Zhong
Published: May 2015

Monodisperse CoFe2O4and Co0.4Zn0.6Fe2O4hollow nanospheres were synthesized in large scale by solvothermal method in ethylene glycol solution. The structure, shape and size of the samples were investigated by Fourier Transform infrared, X-ray powder diffraction and scanning electron microscopy. The results indicate that the products are spherical with an average diameter less than 200 nm. Magnetic studies revealed that the saturation magnetization of Co0.4Zn0.6Fe2O4is 78.6 emu/g, higher than the CoFe2O4, which is 69 emu/g, while the coercivity of the Co0.4Zn0.6Fe2O4is 184 Oe , obviously lower than that of CoFe2O4which is 832 Oe. The electromagnetic parameters were measured at 2-18 GHz using HP8722ES vector network analyzer and then the microwave absorption properties were calculated through the transmission line theory. As to the Co0.4Zn0.6Fe2O4, the absorption bandwidth with reflection loss below-10 dB is up to 3GHz, from 10GHz to 13GHz with a thickness of 2 mm. A maximum reflection loss-45.6 dB was found at 12.9 GHz for the CoFe2O4with a thickness of 1.8 mm. As a result, the as-prepared hollow nanospheres show good prospects of being applied in EM wave absorption materials.
Biological CAD/CAM/3D Printing Integrated Molding Platform and System Building
Authors: Ma Yun Min , Liu Yuan Yuan , Chen Hai Ping , Hu Qing Xi
Published: May 2015

The defective repairing and restructuring of some tissues and organs is becoming a livelihood issue which need settling urgently at present. Using polytechnics to design and prepare regenerated biological scaffolds is now facing a big bottleneck. In this paper, by the study and analyzing of CAD/CAM technology, 3D printing and electro-spinning technology, a new bionic CAD/CAM/3D printing integrated molding platform is expressed to meet the reunification of design and manufacture of regenerated bone scaffolds. Using the integrated molding platform, the Gelatin/chitosan – PVA scaffold were prepared with macro to micro structure. This molding method will help to develop the bio-manufacturing, biological 3D printing and their equipment, and has a realistic significance on pushing human health.
Facile Preparation of Cu/TiO2 Nanocomposite via Photocatalysis and their Antibacterial Performance
Authors: She Bo Xi , Long Jun Biao , Deng Yuan Ming , Wan Xue Juan , Zhu Ke Jun , Tang Jiao Ning
Published: May 2015

Cu/TiO2 nanocomposite was first prepared by photocatalytic reduction according to optimal processing condition selected via orthogonal test: 2.0% of glucose, 0.25% of TiO2, 0.3% of CuCl 2 and reaction time of 12 h. Multiple characterization methods were utilized to confirm the structure of Cu/TiO2 nanocomposite, and its antibacterial property against Escherichia coli (E.coli) was then investigated in detail. The obtained Cu/TiO2 (ca. 50 nm) was composed of elemental copper, TiO2 and a small amount of unreacted CuCl2. EDTA titration and XRF indicated that solid content of Cu was about 61.68%. Antibacterial test showed that the inhibition zone diameter of Cu/TiO2 with 1% solid content is 15.77 mm and the minimum bactericidal concentration (MBC) of which is 5 mg/mL. Furthermore, Cu/TiO2 (1.0 wt%) was added into a super-hydrophilic coating for the aluminum cooling fin of air conditioner. The antibacterial ability of the fin can be significantly improved without obvious changes of hydrophilicity, which can reach the national standard (grade I).
Design of a Microfluidic Chip for Enrichment of Circulating Tumor Cells
Authors: Ling Xi Xin , Ren Da Hai , You Zheng
Published: May 2015

Identification and characterization of CTCs can be used as a tool for the study of cancer metastases. A novel design of microfluidic chip used for enrichment of circulating tumor cells is presented in this paper. An integration of DLD method and negative enrichment method were designed to improve the throughput and recovery rate while getting intact CTCs. The DLD stage is used to separate CTCs from blood cells preliminarily, and the negative enrichment stage is used to acquire purified CTCs. Both of them were simulated with COMSOL Multiphysics. Simulation results showed that triangular micro-posts have better performance in DLD stage, and wave structures could generate better disturbance effect than herringbone structures. This chip provides a potential approach with high throughput and purity for the enrichment of CTCs.
Biological Effect of Single Wall Carbon Nanotubes on Skeletonema costatum and Prorocentrum donghaiense in Seawaters
Authors: Li Fang Fang , Wang Jiang Tao , Tan Li Ju
Published: May 2015

Carbon nanotubes (CNTs) have been used in a variety of industrial areas as a kinds of new nanometer materials. Algal growth test was developed to determine the biological effect of single-walled carbon nanotubes (SWNTs) on Skeletonemacostatum and Prorocentrum donghaiense. The results showed that SWNTs stimulated the growth of S. costatum within 72 h and 24 h as theirs concentrations were smaller than 0.5 mg/L and 10 mg/L respectively, While the growth of S. costatum was inhibited within 48 h and 96 h as theirs concentrations were higher than 10 mg/L and 0.5mg/L respectively (p＜0.05). The concentrations of chlorophyll were the same as the density of phytoplankton cells. The growth of P. donghaiense was inhibited as SWNTs concentrations were higher than 100 mg/L within 72 h, while SWNTs promoted the growth of P. donghaiense within 48 h after SWNTs were added as their concentrations were smaller than 5 mg/L（p＜0.05). The results of chlorophyll were similar to the density of P. donghaiense cells. The roles of SWNTs on the growth of algae were suggested to be associated with the active of some enzymes and the physical properties, such as agglomeration and shading.
An Ultrasonic Micro Knife Based on Triangular Silicon Horn Chip
Authors: Wang Ting Ting , Wu Jing , Ying Ke Man , Li Wen Gang , Guo Hang
Published: May 2015

This paper presents a silicon-based ultrasonic scalpel for minimally invasive surgery. Starting from the fundamental theory, the micro ultrasonic scalpel using triangular silicon horn chip is designed and fabricated in detail. It is found that the magnification of the composed horn keeps 5.8 when size changes. A micro scalpel has been fabricated by MEMS technology. The test results show that a good performance in vibration and fit for puncturing biological tissues at the micro/nanoscale are obtained in the micro ultrasonic scalpel.
Influence of Defects on the Young's Modulus of [110] Silicon Nanowires with Different Cross Sections
Authors: Gu Fang , Zhang Jia Hong , Li Min , Liu Lin Yan , Su Jing
Published: May 2015

The size dependence becomes more significant as the devices scale down from micro-to nanodimensions, which is generally attributed to surface effects due to the very high surface-to-bulk ratios in nanoscale structures. However, significant discrepancies between experimental measurements and computational studies indicate that there could be other influences besides surface effects, such as the influences of native oxide layer, fabrication-induced defects and boundary conditions. In this paper, our purpose is to investigate mainly the influence of fabrication-induced defects on the elasticity of [110] silicon nanowires (SiNWs) with different cross sections. We accomplish this by using the molecular dynamics (MD) simulation. Our MD results show that the H-passivated [110] SiNWs without surface defects is slightly elastically softer than bulk, which is in good agreement with other literature MD values. However, the effective Young’s modulus of SiNWs with surface defects can significantly decreases as the defects increase. This softening behavior of [110] SiNWs is severe, which indicates the importance of surface defects. It is noted that the influence of defects on the Young's Modulus of SiNWs strongly depended on the distribution and morphology of defects as well as the cross-sectional shapes of SiNWs. It is observed that the influence of defects on square SiNWs is significantly different from those of hexagonal and triangle SiNWs. Our work reveals that fabrication-induced surface defects could be one of the important origins of the reduced effective Young’s modulus experimentally observed in ultra-thin SiNWs. Therefore, the effect of defects on the characterization of the mechanical properties of nanowire must be carefully considered.
Study on Internal Stress in Micro-Electroformed Layer
Authors: Du Li Qun , Tan Zhi Cheng , Song Chang , Zhao Zhong , Li Qing Feng , Yin Peng He
Published: May 2015

Micro electroforming technology is widely used in fabrication of multilayer or moveable metal micro devices. The fabrication of these devices is usually suffered from high internal stress in micro-electroformed layers which seriously restricts the application and development of micro electroforming technology. Therefore, to control the internal stress is very important for improving the quality and performance of micro-electroformed layer. However, published studies on internal stress in the electroforming layer were mostly based on additive-free solution. According to additive solution, the effect of ultrasonic and current density on compressive stress occurring in the electroforming layer is investigated in this paper. The results indicate that the compressive stress keeps increasing with current density within range from 0.2 to 2 A/dm2. Meanwhile, the compressive stress in ultrasonic solution decreases by 73.4 MPa averagely comparing to that in ultrasonic-free solution, and the compressive stress also keeps decreasing with the ultrasonic power which gets the lowest value at 200W. Moreover, the mechanisms of additive-induced compressive stress and ultrasonic relieving compressive stress are discussed. This research work will complement the ultrasonic-stress reduction theory and may contribute to the development of micro electroforming technology.
Low Temperature Eutectic Alloy Bonding Used in MEMS-Based Solid Propellant Microthrusters Array
Authors: Ru Cheng Bo , Ye Ying Hua , Xu Jian Bing , Zou Zhen You , Dai Ji , Zhu Peng , Shen Rui Qi
Published: May 2015

Considering the safety of the charge filled in the chambers and the operational reliability, a low temperature eutectic alloy bonding was preferred for the final assembling process of MEMS-based solid propellant microthrusters (SPM) array with top-side igniters. The optimum conditions of the alloy coating are the pH value of the solution is 0.5, the base metal layer is composed of Ti (60nm)/Cu (500nm) deposited by magnetron sputtering. The bonding process was conducted in an oven with air and the bonding temperature is 70°C. To predict the performance of bonding layer, the temperature distributions of eutectic alloy layer were simulated by ANSYS software when the chamber is full of high temperature reactants. The simulation results demonstrated the bonding strength wouldn’t cut down since the heat transfer induced by the combustion of charge. The assembled MEMS-SPM array was tested under constant voltage, the results indicated that the eutectic solder bonding procedure meet the requirements of the MEMS-SPM assembling.
Research on Delamination of Plastic Packaging Device during Reflow Soldering
Authors: Liu Pei Sheng , Lu Ying , Huang Jin Xin , Yang Long Long
Published: May 2015

Due to the application of lead-free solders, the quality and reliability of plastic packaging device are influenced by the increase of reflow temperature. In this paper, a low-profile quad flat package (LQFP) is chosen to illustrate the interface deformation during reflow soldering. The stress analysis theory and the finite element analysis (FEM) simulation are introduced in this paper. By means of finite element software, the distribution of hygrostress, thermal stress and the deformation of device on the printed circuit board (PCB) are analyzed and calculated under different temperature. The relationship between delamination length and deformation is given. The simulation results show that the warping phenomenon is found at the apex angle of the device; delamination is easily produced in the interfaces between different materials by thermal stress, and possibly leads to the device failure.
Preparation of Mn-Zn Ferrite Flake Absorbent by Self-Reactive Spray Forming Technology
Authors: Gao Hai Tao , Wang Jian Jiang , Lou Hong Fei , Cai Xu Dong , Hou Yong Shen
Published: May 2015

Fe+MnO +Fe2O3+ZnO reaction system was used to prepare Mn-Zn ferrite flake absorbent by self-reactive spray forming technology. Extrinsic enthalpy (H) and adiabatic temperature (Tad) of system were calculated. The formation mechanism and electromagnetic properties of Mn-Zn ferrite flake absorbent were analyzed. The results show that Tad exceeded 1998K, self-propagation reaction can be ignited and products can be melted. The droplets impacted onto copperplate to achieve flake shape. SEM and XRD were used to characterize the morphology and phase of samples. The results show that most of flake absorbent are at 100μm wide and 10μm thick, and they are constituted by pure Mn0.5Zn0.5Fe2O4 phase with spinel crystal structure. Absorption test show that the absorbent has two absorption peaks, the minimum value of reflectivity is at -27dB and the bandwidth lower than -10dB reaches to 3.5GHz. The Mn-Zn ferrite flake absorbent provides with preferable properties, which is potential in the further investigations.
Simulation and Typical Application of Multi-Step Diffusion Method for MEMS Device Layers
Authors: Wang Ling Yun , Zhou Ru Hai , Liu Yi Fang , Zheng Cheng , Cai Jian Fa , He Yong
Published: May 2015

In MEMS device, heavily boron doped layers are widely used as structural layers. For the manufacture of the thick heavily boron doped layer (boron concentration ≥ 5×1019 cm-3), conventional two-step method exposes disadvantages of low efficiency and high energy consumption. Hence, multi-step method is introduced to improve the energy efficiency. In our study, simulation of diffusion in silicon is carried out to compare multi-step method with conventional method. The simulation reveals that multi-step method obtains more quantity of boron dopants and shows better potential to fabricate thick heavily boron doped layers, compared to conventional method within the same total diffusion time. As a typical application of the multi-step method, a butterfly-shape resonant is fabricated.