bluuebunny/crossref_metadata_2025 huggingface dataset:
A Reliable Multi-Sensor Navigation System for an Unmanned Aerial Vehicle Realized through Integration of SINS with GPS, CNS and Doppler Radar
Authors: Ushaq Muhammad , Cheng Fang Jian
Published: September 2013

Contemporary importance of the unmanned aerial vehicle (UAV) both for military and civilian applications has prompted vigorous research related with guidance, navigation and control of these vehicles. The potential civilian uses for small low-cost UAVs are various like reconnaissance, surveillance, rescue and search, remote sensing, traffic monitoring, destruction appraisal of natural disasters, etc. One of the most crucial parts of UAVs missions is accurate navigation of the vehicle, i.e. the real time determination of its position, velocity and attitude. Generally highly accurate Strap down Inertial Navigation Systems (SINS) are too heavy to be flown on UAVs. Moreover highly accurate SINS are also highly expensive. Therefore the low-cost and low weight MEMS based SINS with a compromised precision are the viable option for navigation of UAVs. The errors in position, velocity, and attitude solutions provided by the MEMS based SINS grow unboundedly with the passage of time. To contain these growing errors, integrated navigation is the resolution. Complementary characteristics SINS and external non-inertial navigation aids like Global Positioning System (GPS), Celestial Navigation System (CNS) and Doppler radar make the integrated navigation system an appealing and cost effective solution. The non-inertial sensors providing navigation fixes must have low weight and volume to be suitable for UAV application. In this research work GPS, CNS and Doppler radar are used as external navigation aids for SINS. The navigation solutions of all contributing systems are fused using Federated Kalman Filter (FKF). Three local filters are employed for SINS/GPS, SINS/CNS and SINS/Doppler integration and subsequently information from all three local filters is fused to acquire a global solution. Moreover adaptive and fault tolerant filtering scheme has also been implemented in each local filter to isolate or accommodate any undesirable error or noise. Simulation for the presented architecture has validated the effectiveness of the scheme, by showing a substantial precision improvement in the solutions of position, velocity and attitude.
Digital Filament Power Supply Designed for Electron Beam Welder
Authors: Wang Ze Ting , Wang Peng , Fan Sheng Wen , Chen Tao
Published: September 2013

The electron beam welding has high energy density, and the advantages of small welding deformation, in the defense, automotive, shipbuilding, precision machinery and other industries has been widely applied. Traditional electron beam welding machine power supply system adopts the technology of the power frequency or medium frequency, high volume, low efficiency and poor stability of electron beam. Combining with the characteristics of electron beam welding power source and the existing shortcomings, I put forward a digital filament power control scheme based on STM32, and introduce the hardware and software implementation method in detail. Experiments show that it can realize soft-start and soft-down process, and also be quickly identified and promptly forbid the output when filament fracture, which realize the intellectualization of filament power supply.
Research on Voltage and Current Monitoring System for Circuit Breaker
Authors: Liu Peng Peng , Yao Fang , Li Zhi Gang , Luo Yan Yan
Published: September 2013

This article develops the automatic test system of voltage and current dynamic waveform for circuit breaker. The system has the automatic monitoring, the storage and the display function of contact voltage and current waveform of circuit breaker in switching process. And then, it also designs the hardware and software of voltage and current dynamic monitoring system for miniature circuit breaker: the hardware circuit of this test system mainly consists of the detection circuit and the data acquisition circuit of current and voltage. And the software system, which mainly consists of control program, data acquisition program and data processing program, is programmed under the condition of LabVIEW. At last, it carries on the real-time monitor to the voltage and current waveform at the both ends of the circuit breaker, especially for the waveform during the switching process, which contributes to study the arc energy and contact wear of circuit breaker.
A New Isolated Boost Converter with Coupling Inductors
Authors: Zhang Hai Ming , Liao Xiao Zhong
Published: September 2013

This paper proposes a new improved zero-voltage switching isolated boost converter with coupling inductors. With the traditional advantages of smaller input current ripple, low diode voltage rating, and low transformer turns ratio of boost half bridge topology [ being retained, the proposed converter makes it much easier to realize zero voltage switching of primary switches compared with conventional converters.
Miniature Circuit Breaker Electromagnetic Release Simulation and Analysis
Authors: Zhang Jun Fang , Fang Yao , Li Zhi Gang , Luo Yan Yan
Published: September 2013

With the three-dimensional field analysis software Ansoft, we establish three-dimensional finite element model of the electromagnetic release, obtain the electromagnetic release static characteristics of electromagnetic force by simulation, and analyze the relationship between the electromagnetic force, the short-circuit current and the air gap size. By Analyzing the dynamic characteristics of moving iron core, different short-circuit currents influence on the velocity and displacement of the moving iron core was gained.
Study on Characteristic Indexes Indicating the Influence of Pollution and Air Pressure on the DC Flashover Voltage of Insulator
Authors: Chen Ling , Liu Rui , Cao Yong Xing
Published: September 2013

Under low air pressure, dc arcs often levitate from surface of polluted insulator to form air-gap arcs during flashover process. The U-I characteristic of surface arc is different from that of air-gap arc. Considering the characteristic differences between surface arc and air-gap arc, the values of characteristic indexes indicating the effects of pollution and air pressure on flashover voltage are studied theoretically. The theoretical values of the characteristic indexes are also compared with reported experimental data.
Preparation and Properties of PLA/Nano-ZnO Composite
Authors: Ding Li Bo , Rui Jiang , Li Jun Tao
Published: September 2013

In order to study the impact of nanoZnO on the mechanical properties of PLA, nanoZnO modified with different surface treatment agents (titanium ester NDZ-201,silane coupling agent KH550 ) was added to PLA matrix. The samples were examined by fourier transform infrared (FT-IR) spectroscopy, mechanical properties and SEM. The results show that infrared spectra of nanoZnO modified with different treatment agents include two peaks at 2852cm-1and 2925 cm-1, which are corresponding to C-H stretching vibration, peak at 1735cm-1which is corresponding to NH2, and peak at 964cm-1which is corresponding to P-O-Ti.when the addition of nanoZnO reaches to 1wt.%, the tensile strength of PLA/ZnO nanocomposites have the maximum values of 47.43MPa, increase to 9.64% by pure nanoZnO. The mechanical properties of PLA/ZnO nanocomposites can be improved modified with different treatment agents, and the dispersion of nanoZnO has been significantly improved.
Adaptive Backstepping Control for PMSM Integrated Starter Generator
Authors: Li Yan , Sheng Zheng Yin
Published: September 2013

In this paper a speed tracking controller is designed for Permanent Magnet Synchronous Motor (PMSM) integrated starter generator (ISG) operation in the starter based on adaptive backstepping technique. The PMSM drive system is often faced with some parameter variations and unknown disturbances. The designed controller can make the internal combustion engine (ICE) reach ignition speed quickly and meet the torque small pulsating and speed goes smoothly requirements. Then establish the controller model and simulate the ISG operation in the starter. Some simulation results verify the feasibility and illustrate the performance of the controller under the various conditions.
Dynamic Modeling and Simulation of Salient Pole Synchronous Motor
Authors: Shang Chao , Jiang Zhi Fu , Gong Jin Ru
Published: September 2013

Aimed at salient pole machine synchronous motor, the relationship between the current, voltage, flux and torque were analyzed quantitatively, the simplified mathematical model based on abc three-phase variables was established, and it was converted into the model under d/q coordinates which is easily for computer control, finally, it is simulated by Matlab/Simulink.
Control Strategy for Shunt Active Power Filters with Selective Harmonic Compensation
Authors: Yang Xin Hua , Xie Xing Feng
Published: September 2013

To improve the flexibility of compensation and the precision of three-phase shunt active power filter (APF). A double-loop compound current controller was proposed, which repetitive controller as the outer loop, the PI controller as the inner loop. Design method in detail, dynamic response and steady-state characteristic in analysis. And put forward the compound control strategy, which combine selective harmonic detection based on multiple synchronous rotating coordinates with double-loop compound controller, achieved the compensation of zero steady-state error and selective harmonic currents. Both simulation and experimental results verify the effectiveness and correctness of the content.
Effects of Oblique Misalignments on a Coaxial Waveguide Performance
Authors: Xie Yong Chao
Published: September 2013

The effects of the misalignment between the inner-rod axis and the outer-wall axis in an open coaxial waveguide are studied by means of the software CST microwave studio. Results show that the field amplitude and S parameter of TEM mode decreased with the oblique misalignment angle increased. But the effect is little. While the oblique misalignment angle is up to, the field profile of TEM mode is affected largely. So in the practical of engineering applications, we should try to avoid the occurrence of oblique eccentric between the inner rod and outer wall during to technological factors.
A Cylindrical Molten Carbonate Fuel Cell Supplied with Landfill Biogas
Authors: Cotana Franco , Filipponi Mirko , Castellani Beatrice
Published: September 2013

A small size cylindrical Molten Carbonate Fuel Cell stack was installed at Giugliano landfill in Italy. The stack was constituted by 16-cells with a 300 W nominal power. Preliminary tests were performed in order to verify the possibility to supply the stack by the landfill biogas, characterized by low methane content (32%). Results showed that the proposed plant is able to correctly operate also when supplied with low methane content biogas.
Optimization of Voltage and Reactive Power in Substation Based on Probabilistic Forecasting
Authors: Zhang Yong , Zhang Bing Da
Published: September 2013

Optimization of voltage and reactive power in substation is important for improve voltage stability and power quality. In order to avoid the frequent actions of on load tap changer, it is come up with a new control strategy for optimization of voltage and reactive power in substation based on probabilistic forecasting. In this paper the objective function is built to maximize the probability of the voltage qualification, with the times of equipments actions as constraint conditions. To establish the probability model of voltage firstly, the load on low-voltage bus and system voltage are forecasted with the method of forecasting error statistics. In this paper the objective function is built to maximize the probability of the voltage qualification, with the times of equipments actions as constraint conditions. The tap operating times are limited by estimating the risk of the loss of the voltage qualification; Otherwise, capacitors could turn on or turn off by turns, so their operating times is not need to limit. This method applies to 35kV distribution system a town of northern China,and the result demonstrates that it is feasible and effective.
Reactive Power Optimization of Distribution System with Photovoltaic Station Based on Particle Swarm Optimization
Authors: Sun Zhuo Xin , Zhu Yong Qiang , Ye Qing , Jia Li Hu , Tao Xiao Long
Published: September 2013

In this paper, system operating costs as the objective function, considering the reduced costs of system losses after compensation and the adding costs of compensating devices, established reactive power compensation optimization mathematical model of distribution system with photovoltaic station. And to improve the standard particle swarm optimization, adopting particle swarm optimization to optimize an example, optimizing results verify the accuracy and effectiveness of the model and algorithm.
Study on the Coordination of Load Shedding and Under-Frequency Load Shedding (UFLS) in Small Weak Receiving Power System with Wind Power Penetration
Authors: Jia Meng Meng , Xiang Li , Ding Mao Sheng , Ding Jian , Song Yun Ting , Zhang Jian Cheng
Published: September 2013

Frequency influencing factors in small weak receiving power grid with wind power penetration during the disturbance of power shortage are analyzed in this paper, such as wind power penetration rate, wind turbine types, inertia control loop and wind power fluctuation. Based on the influencing factors above, in the light of the phenomenon of large dive depth and long duration of the frequency first swing after fault, the coordination scheme of load shedding and under-frequency load shedding based on the simulation system is proposed: load shedding time and load shedding ratio coordination scheme. Simulation results verify the correctness of the theoretical analysis and the rationality and feasibility of the coordination scheme proposed.
Multi-Objective Generation Scheduling for Energy-Saving and Emission Reduction
Authors: Qin Li Jun , Hao Yu Xing
Published: September 2013

This paper based on the idea of dynamic division of the load curve with the monotonicity of load curve and the PSO algorithm and gets the characteristics section. It fuses the sub-processes with the energy trajectory methods in order to describe the climbing peak and descending valley of the load curve closely, and characterizes the actual load curve. The multi-objective daily generation scheduling model is built based on the lowest cost of thermal power purchase of electricity and the lowest emissions of pollution gas. The optimal power flow based on combination of satisfaction degree and close degree are introduced to transform multi-objective into the single-objective optimization model. Decision makers can make interactive solution via adjusting goal satisfaction degree and close degree,so as to receive satisfactory results considering all aspects and make the daily generation scheduling based on energy-saving and environmental protection.
A Traffic Matrix Recovery Algorithm via Low-Dimension Nature in Smart Grid
Authors: Meng Fan Bo , Zhao Hong Hao , Zhao Qing Qi , Ma Wei Zhe , Qi Zhi Gang , Su Jin You
Published: September 2013

In this literature, we explore the solution of network traffic recovery in smart grid. Taking account of dimensionality of network traffic in smart grid, we propose a novel reconstruction model via network tomography. In our algorithm, we use the low-dimension nature of traffic matrix and the greedy adaptive dictionary algorithm to convert the network tomography into the problem of sparse reconstruction at first. Then we solve network traffic by an iterative greedy algorithm. Simulation results indicate that proposed algorithm exhibits noticeably improvement in estimation error comparing with previous work.
Research on Reducing Direct Current Consumption of Copper Electrical Product
Authors: Zhang Yi , Wen Shu Ming , Liu Dan , Cao Qin Bo
Published: September 2013

The main cost in the production of copper with leaching - extraction - electrical product method come from raw ore, electricity consumption and H2SO4 consumption. In this paper, methods of reducing direct current consumption of copper electrical product were determined. With high standard anode plate, Shorten appropriately hemimorphic spacing, controlling suitable current density and electric fluid temperature, fluid composition control reasonable electricity, short circuit and earth leakage was avoided and copper electrical product power consumption effect was highly reduced.
A Duty Cycle Adjustment Strategy for Embedded Boost Power Factor Correction
Authors: Shi Lei , He Hong Kun , Wang Lin Bo , Yang Jin Jin , Feng Qian Ni
Published: September 2013

The embedded boost power factor correction (PFC), which is realized by a storable duty cycle control method, has been verified that it can achieve good performance when the input voltage is standard sinusoidal signal. But the input current can not keep the good sinusoidal waveform all the time when the amplitude of the input voltage changes. In order to solve the problem, this paper presents a duty cycle adjustment strategy for embedded boost power factor correction. This strategy can adjust the duty cycle data synchronously when the amplitude of the input voltage changes. Its test results show that the adjustment strategy can achieve better performance to make the input current follow the shape and phase of the input voltage. The proposed duty cycle adjustment strategy can get the embedded boost power factor correction more effective and practical.
The Design of Electronic Monitor Used in Hospital
Authors: Dai Jun Feng , Fu Li Hui
Published: September 2013

An electronic monitor for hospital inpatients is designed in this paper. Patients can give a calling signal by button, and the monitor can detect and display the infusion speed and give a alarm in time when the speed is too fast or too slow, in addition, it also can set various time for activity to inform medical staff. The whole system is divided into the host and the extension, the host display the current time and set various time for activities by DS1302 chip, the extension give the calling signal by keyboard, the host receive it through communication and display the bed number, the infusion speed is detected through the photoelectric method and is send to the extension for display and alarm. The monitoring instrument has great application value which can avoid failure during the process of transfusion and improve working efficiency.
TiSiN Films by Reactive RF Magnetron Co-Sputtering for Ultra-Low-Current Phase Change Memory
Authors: Yin You , Hosaka Sumio
Published: September 2013

Our simulation reveals that the programming current of phase change memory (PCM) is expected to dramatically reduce to tens of μA with the help of a heating layer. TiSiN films by reactive RF magnetron co-sputtering are investigated for application to the heating layer of the ultra-low-current PCM. The resistivity of TiSiN films is well controlled from around to with increasing N2partial flow rate to 10%. The effect of annealing on the TiSiN films exhibits the relative stability of the resistivity of the films. This implies that these TiSiN films can be used as a universal heating layer for the intensively researched phase change materials.
Research on a Digital Close-Range Photogrammetric Bridge Deflection Measurement System
Authors: Wang Wan Ting , Liu Han Bing
Published: September 2013

This paper introduces a new close-range photogrammetric bridge deflection non-contact measurement method that has high accuracy and efficiency, and can be conveniently used by engineers without help from professional surveyors. After a general theoretical description (analysis process and program development) of a photogrammetric bridge deflection measurement method, the system configuration is introduced and the application is verified through the laboratory and field tests.
Application of GPR in Measurement of Kunming Lake
Authors: Yang Bo Gang , Zhang Jin Song
Published: September 2013

According to Chinas first census for water requirements, Beijing Institute of Surveying and Mapping measured the Kunming lake reservoir capacity for the first time. Combining with the application of measurement of Kunming Lake storage capacity with GPR, this paper give a method on city lake storage capacity measuring, and then analyses the feasibility of measurement with GPR, summary variety of advantages and disadvantages in this work. In the end, the paper give a lot of advice on Measurement of city lake storage capacity with GPR.
Application of WSN in the Remote Monitoring for Heating Network
Authors: Zhu Lin , Zhang Hai
Published: September 2013

For the characteristics of urban centralized heating system are wide geography coverage and large span of density distribution in the monitoring system but having regular, the paper put forward a remote communication mode combined by WSN and GPRS. As the background of the remote monitoring for the client operating condition in heating network, the paper elaborate the structure of urban remote monitoring system for heating network, and the design idea of its hardware and software. As well as the WSN self-organized protocol is analyzed carefully. The scheme can effectively solve the industrial field problem, which industrial environment is difficult to wire, and the construction and running cost is high in the remote monitoring system. It also has high application value.
Ortho-Rectification of SPOT 6 Satellite Images Based on RPC Models
Authors: Yang Guo Dong , Zhu Xiang
Published: September 2013

In this paper, the technical parameters of SPOT 6 are simply introduced, and the definition and error compensation scheme of the RPC model are discussed in detail. A SPOT 6 image of Beijing area was picked up to test the correction accuracy of SPOT 6 based on the RPC model by using ten schemes. Results show that the accuracy of ortho-rectification can reach 6 pixels (9 meters) without control point. And the RPC model base on affine transformation is the most adaptive for processing SPOT6 image.
Research on Page Format Streaming Partition in Digital Readings of Comics
Authors: Jiang Ya Qing , Zhang Jin , Yang Zi Jian , Liu Xin Xin , Lu Rui
Published: September 2013

In this paper, we propose a method to solve the problem of parting pages of comics and rear-ranging the consequential partial pictures. It is enable portable devices with small screens to display large page format comics. After being divided into single pictures segmentations, large pages are rearranged in an appropriate way for watching in small screen. The key work in segmentation process is to segment large format comic pages by unicom domain detection. And then the method examined by examples of common comics, proving that the algorithms are effective for comics with integral frames and nearly rectangular partial pictures. We also discuss the picture sequence-restructuring problem with empirical prediction method. Experiments are analyzed by this method and the results of which validates the feasibility of the proposed method.
Model Test Studies of the Mechanical Properties of Pile - Soil Interface
Authors: Wang Cheng Hua , Jin Kui , Zhan Chuan
Published: September 2013

The study of the mechanical properties of pile-soil interface is an important aspect to research the vertical bearing behavior of piles. Currently special direct shear tests and special simple shear tests are usually used to study the mechanical properties of soil-structure interface. But those tests have shortcomings of difficulty in simulating the force properties of complex interface. In this paper, the mechanical properties of different interface between soil and concrete surface were studied through the large-scale direct shear tests.
Application of Simulation Technology on Airport System
Authors: An Ran , Yang Xiao Kang
Published: September 2013

With the rapid development of aviation industry which leads to a continuous expansion of the airport and an increasing throughput growth has brought more and more problems to the regular operations of the airport and traffic control. Since simulation can accurately predict the future tendency of a system, especially those complex and stationary systems about airports, it can reduce the waste of recourses and inconvenience to passengers caused by policy mistakes. The article overviews the status of the research on airport simulation technology and summarizes the application of simulation technology in airport system, furthermore, points out the shortage and development of airport simulation.
Health-Based Risk Assessment of a Simple Landfilled Sludge Site
Authors: Yang Ling , Zhang Chun Lei , Li Lei , Agadzi A.K.
Published: September 2013

Based on the methods of health-based risk assessment of contaminated sites and the analysis of heavy metal pollution in a simple landfill sludge site, we assessed the integrated human health risk of soil contamination. It is concluded that the main pollutant is heavy metal. There are three exposure pathways identified: workers inside the site, residents working on the farmland and those living down of the site. This assessment indicates that workers would suffer non-carcinogenic impacts with total multi-pathways non-carcinogenic hazard index for heavy metal being 0.397,and the carcinogenic impacts being 2.2×10-7. The residents working on the farmland would suffer non-carcinogenic impacts with total multi-pathways non-carcinogenic hazard index for heavy metal being 0.788, and the carcinogenic impacts being 4.5×10-7. The residents living downslope of the site would suffer non-carcinogenic impacts with total multi-pathways non-carcinogenic hazard index for heavy metal being 6.22 for adults and 1.25 for children, and the carcinogenic impacts being 3.4×10-6 for adult and 7.5×10-7 for children. Non-carcinogenic index of the site and farmland areas are less than 1, while the non-carcinogenic health risk is negligible. Their carcinogenic index is less than 10-6, and the cancer health risk is small. The adults living downslope of the site have a greater risk of non-carcinogenic and carcinogenic risk. The children have non-carcinogenic risk and dont have carcinogenic risk.
Grey Prediction Model for Water Withdrawals
Authors: Wu Xing Zhao , Wang Xue Di , Wei Shu Yi , Dong Ying
Published: September 2013

Since grey prediction model performed well in feasting with few data, we applied it to predicting water withdrawals. We take the prediction of the water withdrawals in the United States as an example. With the data of water withdrawals in the past 30 years, we forecast how much fresh water will be needed in main states of America, which is crucial for the government to make major constructions in national economy. Moreover, we test the model by applying it in the prediction of annual water use in Chinese main river valleys.
The Review of Studies on Formulas for Calculating Wave Breaking Height
Authors: Yang Jia Xuan , Zhu Shou Xian , Li Xun Qiang , Zhang Wen Jing , Wang Lei
Published: September 2013

Wave breaking is the most complex and intensified physical process in coastal zone. And as the maximum in this area, the breaking wave height has a major impact on ocean engineering and ship sailing. In this paper, the present calculation methods for breaking height are concluded and divided into two categories: one is directly computing models using deep wave elements; the other is indirectly calculation models based on the surf wave calculation model and the criterion of breaking.
Water Depth Inversion in Sanya Bay Based on TM Image
Authors: Zhang Meng Fei , Zhu Shou Xian , Zeng Wen Hua , Zhang Wen Jing
Published: September 2013

Remote sensing technology can be applied to water depth measurement in coastal area [. In this paper, Sanya Bay was chose as the study area. The author combined high spatial resolution TM image and observed water depth data for water depth inversion. The power exponential model based on TM2 is selected because of its least average relative error in all single bands and ratios of two spectra. The result shown in table 2 says that the error is still considerable, so, develop a new inversion method is necessary.
Influences of Thickness and Fabric for Sound Absorption of Biopolymer Composite
Authors: Hassan Nik Normunira Mat , Rus Anika Zafiah Mohd
Published: September 2013

Biopolymer foam was prepared by the reaction of bio-monomer based on vegetable oil with commercial Polymethane Polyphenyl Isocyanate (Modified Polymeric-MDI). The acoustic study of biopolymer foam was examined by impedance tube test according to the ASTM E-1050 and laminated with three types of textile such as polyester, cotton and single knitted jersey. It was revealed that the thicker the fabric the higher the sound absorption coefficient (α) at medium frequency level. The higher the number of layers or thickness of the fabric, the sound absorption through the fabric increases at medium frequency but after the maximum it remains almost unaltered. Three layer of cotton fabric gives maximum α approximately equal to 1 which is 1.104 mm thickness at frequency level of 3000-3500Hz and single knitted jersey gives maximum α at 4th layer of 2200-2700Hz. Meanwhile , the α of biopolymer foam laminated with polyester fabric approximately equal to 1 at lower frequency level of 2000-3000Hz with lower thickness that is 0.668mm. Polyester fabric with lowest thickness shows better α at lower frequency level due to the structure of the fabric. The relationships among the fiber properties such as fiber density, fiber diameter, and fibrous material layer were considered as a factor that influences the sound absorption property.
Mathematical Model for Chip Serration Frequency in Turning of Stainless Steel with Magnetic Damping from Bottom of Tool Shank
Authors: Amin A.K.M. Nurul , Abdullah Fawaz Mohsen , Arif Muammer Din , Jaafar Israd H.
Published: September 2013

Chatter, a violent and often unpredictable relative oscillatory motion between the tool and work-piece, is a serious concern in turning operations. Its occurrence is usually associated with a loud monotonous sound and usually results in increased surface roughness, reduced material removal rates, shortened tool life, and damaged machine-tool bearings. The established theories for chatter are very limited in scope and are often contradicted by empirical evidences. Therefore, chatter avoidance in the past has relied on inefficient techniques like limiting material removal rates or expensive setups such as actuators and ultrasonic vibration damping systems. However, a deeper investigation into chatter formation reveals that chip morphology and segmentation play a significant role during the incidence of chatter. The novel Resonance theory of chatter combines the concept of mode coupling of the machining setup and serrated chip formation, to explain and predict chatter. To validate the postulates of this theory, models for chip serration frequency are essential. At the same time, a reliable and economical chatter control method is required. With this goal, the current research work has developed an empirical mathematical model of chip serration frequency in turning of stainless steel AISI 304 using Response Surface Methodology (RSM). Also, it investigated the influence of damping provided by magnetic field from a permanent ferrite magnet placed beneath the tool shank. The developed chip serration model is in good accord with the experimental data, demonstrating that the empirical model could be used for further chip morphology and chatter analyses.
Nanoclay Supporting Materials for Enzymes Immobilization: Kinetics Investigation of Free and Immobilized System
Authors: Abd Rahim Siti Noraida , Sulaiman Alawi , Ku Hamid Ku Halim , Mohd Rodhi Miradatul Najwa , Mohibah Musa , Hamzah Fazlena , Edama Nurul Aini
Published: September 2013

In this paper, the kinetic parameters of free and encapsulated enzymes in the calcium alginate-clay beads were determined using Lineweaver-Burk plot. The Michaelis constant, Km of free alpha-amylase, glucoamylase and cellulase were 2.0831, 1.8326 and 7.8592 mg/mL, respectively, whereas for the encapsulated system, the Km values were 3.1604, 2.1708 and 9.2791 mg/mL, respectively. The results showed encapsulation enzymes gave higher Km value than the free enzymes. Comparatively the encapsulated alpha-amylase was 1.5 times higher and the glucoamylase and cellulase were 1.18 times higher. This suggests that the affinity of encapsulated enzymes for substrate was lower which might be due to the diffusional limitation of the substrate and enzymes. Amongst the three in both systems, glucoamylase was determined to have highest affinity followed by alpha-amylase and cellulase enzymes.
Mechanical Properties of Tempered Ti-Nb Alloyed Ductile Iron
Authors: Abdullah Bulan , Alias Siti Khadijah , Jaffar Ahmed , Abdullah Abdul Hakim , Latip Syazuan Abdul , Idham M. F.
Published: September 2013

The applications of ductile iron in numerous engineering applications require continuous effort in properties enhancement due to the necessity of product sustainability and performance. The studies highlighted the effect of 0.5 wt% titanium and niobium addition the mechanical properties of tempered ductile iron. The samples were prepared through conventional CO2 sand casting process. Heat treatment was conducted by austenitizing at 900°C for 1 hour and subsequently oil quenching before tempered at three different temperatures which are 500°C, 600°C and 700°C at 1 hour holding time. The mechanical properties were evaluated through impact (ASTM E23) and hardness (Rockwell) test. Microstructure observation and XRD analysis was also performed on as cast and tempered samples. The findings indicated that increasing the tempering temperature at 700°C enhanced the hardness and tensile strength of tempered alloyed ductile iron compared to other samples. The enhancement of the mechanical properties of tempered alloyed ductile iron is expected to further expand the applications of ductile iron.
Effect of Carbon Fibre Ratio to the Impact Properties of Hybrid Kenaf/Carbon Fibre Reinforced Epoxy Composites
Authors: Bakar Mimi Azlina Abu , Ahmad Sahrim , Kuntjoro Wahyu , Kasolang Salmiah
Published: September 2013

Effects of the incorporation of untreated and treated hybrid kenaf/carbon fibre reinforced epoxy composites on the impact properties were studied. Hybrid kenaf/carbon fibres and thermoset matrices were hand-laid up and characterized in terms of its mechanical properties. The kenaf fibres were alkali treated whilst the carbon fibres were gamma radiation treated before use as reinforcement in the epoxy resin matrix. The reinforcing effects of kenaf hybridized with carbon fibre in epoxy composites were evaluated at various fibre loadings with overall fibre contents 20 wt%. Hybrid composites with different ratios of kenaf fibre : carbon fibre ; 0.9:0.1, 0.8:0.2, 0.7:0.3 and 0.6:0.4 were prepared. Impact tests of untreated and treated hybrid kenaf/carbon fibres were performed. The fractured surfaces of these composites were investigated by using scanning electron microscopic technique (SEM) to determine the interfacial bonding between the matrix and the fibre reinforcement. It was found that the treated hybrid composites increased the impact strength by 26% compared to the untreated ones.
Synthesis Route towards Fine and Monodisperse Ni Nanoparticles via Hot-Injection Approach
Authors: Nik Roselina N.R. , Azizan Aziz , Hyie Koay Mei , Mardziah C.M. , Kasolang Salmiah , Alias Siti Khadijah , Salleh Z.
Published: September 2013

Manipulation of adding sequences have been found to influence the reaction rate, thus made it easier to produced controllable Ni nanoparticles. Hot-injection approach shown capability to significantly reduce the production time of Ni nanoparticles compared to the conventional one-pot synthesis. With minor modification on conventional polyol method, narrow, monodispersed and highly yield spherical nickel (Ni) nanoparticles were successfully produced at synthesis temperature of 60°C. Three mixing methods were investigated to study its efficiency towards producing rapid and narrower size distribution of Ni nanoparticles. Reduction processes were proposed each of the method. As-synthesized Ni nanoparticles were characterized with Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM) and Fourier transform infrared spectroscopy (FTIR) to analyze the size, morphology and interaction of reactants. Fine particles size distribution revealed that when hydrazine was first heated, reaction rate improved tremendously.
Dimensional and Thermal Stabilities of Nanomodified-Epoxy Systems
Authors: Jumahat Aidah , Soutis Constantinos , Abdullah Shahrul Azam , Bahsan Rosnadiah
Published: September 2013

The effect of nanosilica, multiwalled carbon nanotubes (MWCNT) and montmorillonite (MMT) nanoclay on thermal properties of Epikote 828 epoxy polymer was studied. Thermo-mechanical analysis was conducted on three types of nanocomposites which contain 5-25 wt% nanosilica, 0.5-1 wt% MWCNT and 1-5 wt% MMT nanoclay. The effect of nanofillers on the coefficient of thermal expansion (CTE), thermal strain and glass transition temperature (Tg) of the modified and unmodified resins was investigated. It was found that the addition of nanofiller improved the dimensional stability of the polymer. All nanomodified-polymer systems have lower CTE compared to that of the unmodified resin.
Storage Modulus Capacity of Untreated Aged Arenga pinnata Fibre-Reinforced Epoxy Composite
Authors: Khalid Muhamad Faris Syafiq , Abdullah Abdul Hakim
Published: September 2013

Research on natural fibre is keeps on going due to their high strength and stiffness, natural availability, and environmental friendliness. In addition, they are also recyclable, renewable and low in raw material cost. This study was done to determine the performance of aging Arenga Pinnata fibre-reinforced epoxy composite (APFREC) on varying temperature. The specimens were aged from 0 to 90 days by using accelerated aging process and were subjected to dynamic mechanical analysis (DMA) and flexural modulus evaluation. The results have shown that specimens with lower aging days have higher storage modulus initially, that is at below 70 °C but as the temperature increase, its storage modulus drastically decrease in comparison to a more aged specimen. Result of storage modulus at low temperature is similar flexure modulus evaluation. The research indicates that aging APFREC specimens has better thermal resistance.
Machinability Improvement for Stainless Steel AISI 304 in Turning by Applying Magnetically Damped Cutting
Authors: Mohammad Ummu Atiqah Khairiyah B. , Amin A.K.M. Nurul , Arif Muammer D. , Muthalif Asan Gani Bin Abdul
Published: September 2013

Stainless steels resistance to corrosion and staining, low maintenance and familiar luster make it an ideal material for many applications. The alloy is used in cookware, cutlery, household hardware, surgical instruments, major appliances, industrial equipment (for example, in sugar refineries) and as an automotive and aerospace structural alloy and construction material in large buildings. However, machining of this material is difficult due to high cutting force, lower tool life and high intensity of chatter related to its serrated chip formation behavior. An attempt to reduce chatter and thereby increase the tool life and surface finish by employing magnetic field during turning of the material has been made. A special fixture was designed and used to mount the permanent magnet with high power of 4500 Gauss at the bottom of the cutting tool. An accelerometer was attached at the bottom of the tool holder of 120 mm overhang and connected to the vibration data acquisition system. The vibration amplitude data were recorded at in the frequency range of 0 to 5 kHz. The recorded vibration signals were analyzed using DasyLab software (version 6). Response surface methodology (RSM) was employed in developing the chatter acceleration amplitude models in relation to primary cutting parameters: cutting speed, feed, and depth of cut. Design-expert software was applied to develop the second-order models for the two peak amplitudes observed at approximately at 1 kHz and 5 kHz and to develop the contours. The adequacy of the predictive models was verified using analysis of variance (ANOVA) at 95% confidence level.
Identification of Optimum Heating Temperature in Thermal Assisted Turning of Stainless Steel Using Three Different Approaches
Authors: Nurul Amin A.K.M. , Arif Muammer Din , Rasdi Noor Hawa B. Mohamad , Mahmud Khairus Syakirah B. , Ibrahim Abdul Hakam B. , Zawani Mohd Firdaus B. , Malik Amir Faris B. Abdul
Published: September 2013

Thermal or heat assisted machining is used to machine hard and difficult-to-machine materials such as Inconel and Titanium alloys. The main concept is that localized surface heating of the work-piece reduces the yield strength of the material significantly, making it amenable to plastic deformation and machining. Thus, heat assisted machining has been used for over a century. However, the heating technique and temperature are very much dependent on the type of working material. Therefore, a multitude of heating techniques has been applied over the years including Laser Assisted Machining (LAM) and Plasma Enhanced Machining (PEM) in the industry. But such processes are very expensive and have not been found in wide scale applications. The authors of the current research have therefore looked into the application of a simple Tungsten Inert Gas (TIG) welding setup to perform heat assisted turning of AISI 304 Stainless Steel. Such welding equipment is relatively cheap and available. Also, stainless steel is perennially used in the industry for high strength applications. Hence, it is very important to determine with optimal cutting temperature when applying a TIG setup for heat assisted machining of stainless steel. This paper describes three separate techniques for determining the optimum temperature. All three processes applied the same experimental setup but used different variables for evaluating the best temperature. The first process used vibration amplitude reduction with increment in temperature to identify the desired temperature. The second process used chip shrinkage coefficient to locate the same temperature. And finally, the third process investigated tool wear as a criterion for determining the optimum temperature. In all three cases the three primary cutting parameters: cutting speed, feed, and depth of cut, were varied in the same pattern. The results obtained from all three approaches showed that 450oC was undoubtedly the best temperature for heat assisted machining of stainless steel.
Fibre Misalignment Measurement of Nanomodified-Unidirectional Carbon Fibre Laminates
Authors: Jumahat Aidah , Soutis Constantinos , Ali Nor Merlisa , Mahmud Jamaluddin
Published: September 2013

This paper investigates the effect of nanosilica on the fibre waviness or misalignment angle distribution of carbon fibre reinforced polymer composite unidirectional laminates. The quality of the laminates was evaluated using image analyzer technique. The polished specimens were examined using Polyvar B-met optical microscope and analysed using KSRUN ZEISS software. The effect of 3, 7 and 13 vol.% nanosilica on the fibre misalignment angle distribution was determined. The results showed that, the fabricated laminates have average fibre volume fraction Vf of 42%, low fibre waviness distribution (average φo = 2.5o) and less than 1% void content. This implies that the fabrication technique, which was employed in the current work, successfully produced good quality laminates. The presence of nanosilica results in a narrow fibre angle distribution in the HTS40/828 laminate.
Optimization of Surface Roughness and Recast Layer Thickness in the Wire-EDM Process of AISI D2 Tool Steel Using Taguchi-Grey-Fuzzy
Authors: Soepangkat Bobby Oedy Pramoedyo , Pramujati Bambang
Published: September 2013

In this paper, the optimization of surface roughness and recast layer thickness of a WEDM process of AISI D2 steel was investigated by using Taguchi method, grey relational analysis and fuzzy logic. The experiments were conducted under varying flushing pressure, on time, open voltage, off time and servo voltage. An orthogonal array, signal-to-noise (S/N) ratio, grey relational analysis, grey-fuzzy reasoning grade and analysis of variance were employed to the study of the multiple performance characteristics. Experimental results have shown that machining performance characteristics in WEDM process of AISI D2 steel can be improved effectively through the combination of Taguchi method, grey relational analysis and fuzzy logic.
The Effect of Carburizing Medium on Carbon Dispersion Layer of ASTM A516 Steel
Authors: Alias Siti Khadijah , Abdullah Bulan , Abdullah Abdul Hakim , Latip Syazuan Abdul , Wahab Nor Aini , Ghani Muhd Azimin Ab
Published: September 2013

Carburizing had been a renowned case hardening method for most metal which produced hard casing protecting the surface, resulting in improvement of the mechanical, wear and corrosion behaviour. Carburizing in solid medium offer low cost advantages, thus it is widely implemented. The objective of this study is to compare the carbon thickness layer formed after carburizing process at two different solid medium which is powder and paste form. ASTM A516 Grade 70 mild steel was use as the sample in this study. Carburizing process in both powder and paste medium are conducted at three different temperatures which are 850°C, 900°C and 950°C for 8 hours holding time and cooled in room temperature, for comparison purpose. The thickness layer observation and measurement was carried out using optical microscope and XRD analysis was also conducted to validate the carbon appearances. Rockwell hardness test was also performed before and after carburizing process. The findings from this study indicated that paste carburized samples induced deeper carbon diffusion compared to powder carburized samples. Higher carburizing temperature is also favorable in enhancing the thickness layer in both powder and paste carburized samples. It could be stated that comparable thickness layer could be achieve faster in paste carburized samples, compared to powder carburized samples, which can lead a more cost effective carburizing process.
Boron Dispersion Layer of Paste Boronized 304 Stainless Steel before and after Shot Blasting Process
Authors: Alias Siti Khadijah , Abdullah Bulan , Latip Syazuan Abdul , Nik Roselina Nik Roseley , Jenal Norhisyam , Kasolang Salmiah
Published: September 2013

Boronizing had been extensively used in enhancing the properties of metallic material such as steel by formation of hard casing on the surface of the substrate. This study highlighted the effect of applying surface deformation process which is shot blasting on the dispersion layer of paste boronized 304 stainless steel. Boronizing treatment was conducted using two different temperatures which are 850°C and 950°C for 6 hour holding time. Shot blasting process was conducted onto the surface of the samples before boronizing process in order to allow deeper boron dispersion layer. Microstructure and boron dispersion layer measurement were then accomplished using optical microscope. XRD analysis was performed to validate the existence of Fe2B phases and Rockwell hardness test was also conducted to obtain the hardness values. The results indicated that combinations of high boronizing temperature and shot blasting process facilitate deeper dispersion layer. Deeper dispersion layer are paramount as it will enhanced the hardness and wear properties.