bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Fault Diagnosis Based on AGA and LSSVM
Authors: Zhang Da Wei , Zhang Kai , Jiang Jing
Published: November 2011

Support vector machine (SVM) has excellent learning, classification ability and generalization ability, which uses structural risk minimization instead of traditional empirical risk minimization based on large sample. The perfect performance of SVM will be realized only if the parameters are rightly selected. The accuracy and efficiency of classification largely depend on the quality of the parameters selection. Focusing on the problem of the parameters selection in least squares support vector machine (LSSVM), a new method is proposed to optimize the parameters in LSSVM using adaptive genetic algorithm. The research is provided using this method on the fault diagnosis of a certain type of helicopter’s helicopter-electrical-box. Simulated results show that the proposed method achieves perfect accuracy and efficiency in fault diagnosis.
Synchronous Controller of LED Video Displays and LED Lighting Compatible
Authors: Sun Jian She , Feng Xiao Ning , Sun Yi Fei , Zhao Hui
Published: November 2011

The development of a large display and can control a variety of compatible lighting control system, the system is suitable for wide range control distance. Can be widely used in modern college park, landscape building, business building and landscaping all buildings, publicity, service, advertising and other large screen and lighting systems. Using large-scale high-speed FPGA technology, Gigabit fiber communication technology, through a multi-level processing and protocol conversion, can be terminal for the different display mode (divided into static, 2 sweep, sweep 4, 8, sweep, sweep five kinds of 16), data in the order, alignment methods, control methods, the preparation of their own in the FPGA, the protocol conversion module, through the software are free to choose set the display terminal type, to achieve 16 control port can be controlled separately different types of display terminal. Control distance up to 5000 meters or more. Effectively address all the original control system can not be compatible, not centralized control, can not share resources and control of the key problems of distance is too short.
Effect of Nitrogen Doping on the Structure and Optical Properties of N-Type Hydrogenated Amorphous Silicon Thin Films
Authors: Wu Mao Yang , Li Wei , Fu Jun Wei , Qiu Yi Jiao , Jiang Ya Dong
Published: November 2011

Hydrogenated amorphous silicon (a-Si:H) thin films doped with both Phosphor and Nitrogen are deposited by ratio frequency plasma enhanced chemical vapor deposition (PECVD). The effect of gas flow rate of ammonia (FrNH3) on the composition, microstructure and optical properties of the films has been investigated by X-ray photoelectron spectroscopy, Raman spectroscopy and ellipsometric spectra, respectively. The results show that with the increase of FrNH3, Si-N bonds appear while the short-range order deteriorate in the films. Besides, the optical properties of N-doped n-type a-Si:H thin films can be easily controlled in a PECVD system.
Memristor Oscillators and its FPGA Implementation
Authors: Qi Ai Xue , Zhang Cheng Liang , Wang Guang Yi
Published: November 2011

This paper presents a method that utilizes a memristor to replace the non-linear resistance of typical Chua’s circuit for constructing a chaotic system. The improved circuit is numerically simulated in the MATLAB condition, and its hardware implementation is designed using field programmable gate array (FPGA). Comparing the experimental results with the numerical simulation, the two are the very same, and be able to generate chaotic attractor.
Mechanism and Suspension Control Study for Spherical Reluctance Motor with Magnetic Levitation
Authors: Zeng Li , Wang Jun , Zhang Dan
Published: November 2011

This paper presents a novel Multi-Degree-of-Freedom spherical reluctance motor with magnetic levitation, it analyses mechanism of magnetic force and electromagnetic torque that spherical motor generates. Conducted a comprehensive control of the spherical motor and analysis and simulate the results of the suspension control system. The simulation experiments show that the state synchronization suspension control owns high precision and immunity to interference.
Study on Rheo-Diecasting for In Situ Synthesized Mg2Si/AM60 Composites
Authors: Yan Hong , Hu Yong , Wu Xiao Quan
Published: November 2011

Magnesium alloys have high specific strength, specific stiffness, excellent thermal conductivity and casting properties, which have a great prospects development in the industry, However, its low plasticity and ductility limited its application. Magnesium matrix composites can effectively improve its performance. Magnesium alloy die-casting is the main forming process, the conventional high-pressure die-casting (HPDC) defects in multi-cavity type, easy to volume gas, non-heat-treated. Compared with HPDC, the rheo-diecasting (RDC) process has been greatly developed for near-net shape components. In this paper, Mg2Si /AM60 composites is fabricated by in-situ synthesis and semi-solid magnesium matrix composites which are rheoformed in the die-casting machine are prepared by mechanical stirring. The results indicate that the microstructure of composites is non-dendritic and Chinese script type Mg2Si are fine distributed. The fundamental morphology of microstructure by HPDC is dendrite and liquid-phase distributed between dendrite irregularly. The RDC samples have close-to-zero porosity, less segregation, the most of semi-solid of microstructure in rheo-diecasting is spherical or as-spherical structure.
An Axial-Flux Hybrid Excitation Flux-Switching Machine
Authors: Zhu T. T. , Deng Zhi Quan , Wang Yu
Published: November 2011

A flux switching permanent magnet (FSPM) machine has the advantage of high power density, high torque density, inherently sinusoidal back EMF, stable structure, and the disadvantage of magnetic field uncontrollable. This paper proposes a novel axial-flux hybrid excitation flux-switching (AFHEFS) motor, which offers three phase symmetrical sinusoidal flux linkage and linearly regulated electromagnetic torque as well as excellent flux regulation capability and even field elimination ability with a size ratio of 1:2 between PM stator and electrical stator. The results are validated by 3D finite element (FE) analysis.
Improvement of Passive Location Precision Using ‘Beidou’ Navigation System
Authors: Gu Neng Hua , You Ting
Published: November 2011

This article raises an improved program of adding Pseudo-Satellite’s pseudo-range measurement and setting best configuration for Pseudo-Satellite in mentioned program on the basis of existing Binary System [1]. Through comparison and analysis of improved Tri-satellite System and existing Binary System, this article proves that it shortens location time and location precision by adding Pseudo-Satellite to Binary Navigation Location System. Finally this conclusion is approved by simulating Mathematical model using software.
The Factors Influenced to Surface Finish in Milling for Hardened Medium Carbon Steel: JIS S50C
Authors: Jirapattarasilp Komson , Kaewkuekool Sittichai , Phongphatrawut Worapong
Published: November 2011

The aim of this research was to study factors, which was influenced on surface roughness in vertical milling of hardened medium carbon steel. The specimen was medium carbon steel grade JIS S50C that was hardened at 56± 2 HRC. Full factorial experimental design was conducted by 3 factors and 3 levels (33 design) with 2 replications. Studied factors were consisted of cutting speed, feed rate, and air coolant pressure. The results revealed that influenced factor affected to surface roughness was cutting speed and feed rate which showed significantly different. Higher cutting speed would cause on better surface quality. On the other hand, poorer surface quality was produced by higher feed rate. However, factors interaction were found between cutting speed with air coolant pressure and feed rate with air coolant pressure that significantly influenced to surface roughness. The interaction of high cutting speed with high air coolant pressure would be better quality of surface finish and lower feed rate with high air coolant pressure would be better surface quality.
On the Mechanism of the Effect of the Cryogenic Treatment on High Speed Steels
Authors: Gogte Chandrashekhar , Peshwe Dilip , Likhite Ajay , Lomte Sachin
Published: November 2011

The effect of subzero treatment on tool steels is well known, and is commercially practiced for certain varieties of tool steels. Substantial research is being carried out on the behavior of tool steels after cryogenic treatment (CT). While it has been established that CT improves the wear properties in some steels, the mechanism of this behavioral aspect is not yet fully known. Most work has been focused on AISI M2 high speed steel related to the effect on different properties, but the microstructural change is not yet conclusively identified. Neither the past research has brought forth the exact principles on which CT should be based. Some of these important issues are addressed in this paper.
Applications and Prospects of Hollow Micro/Nanospheres in Environmental Protection and New Energy
Authors: Cui Xing Yu , Zhang Ning , Yao Pu Yu , Liang Bin
Published: November 2011

Hollow micro/nanosphere materials have the especial structure, excellent physical and chemical properties, so they have the broad application prospect in some fields, such as energy conservation, environmental protection, new energy and so on. This paper summarizes the adhibition of hollow micro/nanosphere materials in energy conservation, environmental protection, new energy and so on. And this paper prospects the research area and application prospect of the hollow micro/nanosphere material.
Based on Adams and Matlab Co-Simulation and Experimentation Research for Independent 4WD EV
Authors: Zhao Yu Qin , Zhang Run Sheng , Li Li Ye , Zhang Zhi Jun
Published: November 2011

Analyzing the structural property of model vehicle, a multi-body dynamic model of a full independent 4-wheel-drive electric vehicle(4WD EV) is established by using automatic dynamic analysis of mechanical systems (ADAMS) software, and an electric motor and drive-control system is established under Matlab/Simulink environment. Co-simulation based on the two soft wares is under control of the equality power driving force distribution strategy controller. The results of co-simulation show that the co-simulation is effective and the model’s rationality is validated. It could be applied in the following experiments in complex circumvents, and give theoretic supports.
Based on Linear Quadratic Regulator Optimal Control of Single Inverted Pendulum System Co-Simulation of ADAMS and SIMULINK
Authors: Xu Zhao Yang , Huang Xiao Diao
Published: November 2011

In this paper, based on linear quadratic optimal control design the controller of single inverted pendulum system, using the current epidemic method of Co-simulation to play each of the strengths of two software for simulation, Through two methods of the static and dynamic to observe and analyze the quality of feedback controller the based on linear quadratic optimal control.
Simulation Study of Damage Identification Method Based on Lamb Wave Scattering in Aluminium Plate
Authors: Tian Zhen Hua , Li Hong Yuan , Xu Hong
Published: November 2011

The propagation of scattering Lamb wave in plate was simulated using transient dynamic analysis in ANSYS. In order to extract the characteristic information of received signal for damage identification, the short time Fourier transform based on time-frequency analysis was utilized, and then the energy distribution and envelop of received signal were obtained. Based on the displacement contour of simulation and energy distribution, the propagation of scattering wave in plate with a through hole was examined. Also, a mathematic relationship between damage location and scattering signal was developed, with the help of wave propagation path through actuator, damage and sensor. A nonlinear optimization method was applied on the mathematic relationship to obtain the damage location. The damage identification method using scattering Lamb wave was therefore established.
Molecular Dynamics Simulation of the Rapid Solidification of Liquid Zinc
Authors: Ma Rui Na , Qiu Hong Chen , Wu Jian Jun
Published: November 2011

Molecular dynamics simulation based on the Morse potential is carried out to investigate the rapid solidification of Zn. Radial distribution function, the energy analysis, Voronoi polyhedral structure analysis are used to analyze the microstructure evolution of solidification process. The results showed that amorphous structure formed when the cooling rate exceeded 2.5×1012K/s; crystal formed when the cooling rate less than 7.0×1011K/s; complex structure formed when the cooling rate was between7.0×1011K/s and 2.5×1012K/s.
Zero Internal Force Control for a Dual-Arm Space Robot
Authors: Zhao Hong Cai , Wang Cong Qing
Published: November 2011

This paper discuses the zero internal force control of a dual-arm space robot installed on a free-flying spacecraft without base position and orientation control holding a single object. In order to save energy consumption, scheme with zero internal forces control, in which the disturbance to the base can be effectively decreased. The validity of this method is proved by computer simulations for a grasp system with a dual-arm space robot of three freedoms.
Steering Wheel Angle Pulse Input Simulation and Evaluation of a Car Based on ADAMS
Authors: Liu Yong Chen , Sun Li
Published: November 2011

Vehicle’s steering wheel angle pulse input performance was an representative test of handling and stability, it characterizes vehicle’s handling and stability by the transient response of the steering wheel angle pulse input. Taking a car for example, in the ADAMS software, vehicle dynamics model was established. According to GB/T6323.3—94 standards, the steering wheel angle pulse input virtual test was carried out, and then applied the QC/T 480—1999 limit vehicle handling and stability indices and assessment methods to evaluate the results of the simulation, the result is 66.2247 points, among that, the resonant peak level is 36.0973 points, indicating the vehicle's steering transient response ability is poor, should be improved.
The Fuzzy Immune PID Control Based on the Water Position of the Steam Generator
Authors: Xue Yang , Wang Ting
Published: November 2011

In this paper, through a series of experiments in steam generator, which located in the simulation platform of nuclear power, the model of the water position of the Nuclear Steam generator is concluded. Comparing with traditional PID control, adoption of fuzzy immune control strategies gets better results. The thesis also verifies the excellent self-adaptive ability the fuzzy immune PID control possesses.
The Pole Width Modulation Method and Experiment on Reducing the Voltage Harmonic of PM Wind Generator
Authors: An Yue Jun , Zhao Wen Qiang , Wen Hong Liang , Liu Guo Ming , Yuan Hao
Published: November 2011

The voltage harmonic is an important indicator to evaluate the power quality of PM wind generator. Voltage waveform is closely related to the degree of the air-gap magnetic field waveforms sinusoidal in the motor, so generator structure optimization to improve the degree of air-gap magnetic field sinusoidal is an effective method to improve the quality of generator voltage waveform. This paper presents a method called pole width modulation method to reduce voltage harmonic of wind permanent magnet generator. Do respectively finite element analysis to traditional surface permanent magnet generator and a new very wide modulation permanent-magnet generator; and then develop two structure prototypes and build voltage waveform experimental equipment to study them. Finite element analysis and prototype experiments show that the pole width modulation method is one of the effective and feasible technologies on reducing the voltage harmonic of PM Wind Generator.
A Path Planning Approach for Wedge/Aspheric Lens Element Grinding Based on Space Coordinate Transformation
Authors: Zhang Ning Ning , Jiang Chen , Wang Zhen Zhong , Guo Yin Biao
Published: November 2011

Wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which plays an important role in the fields of liquid crystal projection display, laser fusion, high-energy laser, satellite optical system and large astronomical telescope, etc. Wedge/aspheric lens element are primarily manufactured by CNC machining, especially 3-axis CNC grinding. This paper presents a facile tool path generation approach based on space coordinate transformation. The proposed method can be used to improve and automate three-axis Wedge/aspheric lens element machining for CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed to compare with the desired part.
Vision-Based Guidance for an Unmanned Aerial Vehicle Following a Moving Target
Authors: Qin Tian , Chen Wan Chun , Xing Xiao Lan
Published: November 2011

This paper presents a real-time optical flow algorithm for a vision-based guidance of an unmanned aerial vehicle (UAV). The optical flow algorithm detects a moving target, and obtains the optical position and optical flow vectors of the target from the image sequence. Then, a vision-based guidance of the UAV is designed to follow the moving target. Additionally, the control law of the imaging seeker uses visual information from the image sequence for target tracking. The method was tested on a 3 degree of freedom (3DOF) dual-rotor UAV with a video camera and the result proved the effectiveness of this method.
Robust Tracking Control Based QFT and Pade Approximation for Flight Simulator
Authors: Liu Zheng Hua , Shen Dong Kai , Liu Shi Zhang
Published: November 2011

A new design technique based QFT and Pade Approximation for tracking control has been proposed. QFT controller attempts to place all plant poles within a specified region on the s-plane to guarantee the desired closed loop performance. As for the robust dynamic tracking performance, a new algorithm to design the feedforward controller based pade approximation has been prescribed in the case that the preview information of the desired output is not available. Simulation results for flight simulator show that the proposed approach is effective, successful and applicable.
The Toxic Effects of Algicidal Bacteria L7’s Algicidal Components to Brachydanio rerio
Authors: Zhang Chun Min , Zhang Ya Lei , Pan Wei Bin
Published: November 2011

In order to study the toxic effects of L7 lyophilized powder of extracellular active components (L7-LPEAC) – extracted from the algicidal bacteria L7 – on the aquatic system, Brachydanio rerio were exposed to L7-LPEAC in five different concentrations for a period of 96 hours. The results showed that the 96 h-LC50 is 0.85 g/L, thus the safe concentration is 0.09 g/L. Based on this, four L7-LPEAC concentrations (0.06 g/L, 0.09 g/L, 0.13 g/L, 0.18 g/L) were prepared with the same logarithmic distance, and a 20-day sub-acute toxicity test was carried out. The SOD and ATPase activity in the liver and gill of Brachydanio rerio was measured every 5 days. The results showed that with the increase of L7-LPEAC concentration, the SOD activity decreased significantly (P<0.05), both in liver and gill. Exposed over 10 days, the ATPase activity had little change when the concentration of L7-LPEAC was less than 0.09 g/L; and decreased significantly (P<0.05) when the concentration of L7-LPEAC was above 0.09 g/L.
High Throughput Speciation Analysis of Mercury in Water Environment by Short Column Capillary Electrophoresis On-Line Coupled with Inductively Coupled Plasma Mass Spectrometry
Authors: Li Bao Hui , Tian Bao Juan
Published: November 2011

A method for mercury high throughput rapid speciation analysis was built by short column capillary electrophoresis (SC-CE) coupled with inductively coupled plasma mass spectrometry (ICP-MS). A micromist nebulizer was employed to increase the nebulization efficiency and a laboratory-made removable SC-CE-ICP-MS interface on the basis of cross design was applied to alleviate buffer contamination of ICP-MS. In less than 60 s methylmercury (MeHg(I)) and inorganic mercury (Hg(II)) were separated in a 16 × 75 μm i.d. short column fused-silica capillary at 21 kV, while a mixture of 30 mmol/L boric aicd + 5% (v/v) CH3OH (pH=8.60) acted as running electrolyte. The precisions (RSD, n=5) of migration time and peak area for MeHg(I) and Hg(II) were in the range of 1.4-2.6% and 3.3-3.4%, respectively. The limits of detection (3σ) mercury species were 9.7 and 12.0 μg/L, respectively. The recoveries for Hg(II) MeHg(I) were in the range of 96-107% and 99-105%.
Feed Forward Active Disturbance Rejection Control Method for Common-Rail Pressure Control of Diesel Engine
Authors: Huang Wen Qing , Zhang You Tong , Huang Guo Jun
Published: November 2011

The precise pressure control in common rail is the prerequisite for the excellent performance of common rail diesel engine. Because of the complexity of engine working conditions, conventional PID controller cannot meet the demand of flexible control of common rail pressure, especially when engine load changes largely and rapidly. To overcome the shortcomings of conventional PID, feed forward Active Disturbance Rejection Control (ADRC) has been applied in the common rail pressure control system. The high pressure common rail system layout is drawn and the principle of common rail pressure control is introduced. Four control functions are carried out: “Rail pressure set point calculation”, “Feed forward controller”, “ADRC controller”, and “Flow to duty cycle”. Finally, experimental results comparing between feed forward ADRC controller and conventional PID controller shows that: feed forward ADRC controller is more effective than conventional PID controller because it is smaller in error, quicker in track speed and stronger in anti-jamming ability. It ensures the common rail engine meet the strict specification of the law based on the good dynamic performance.
Electrical Properties of Multilayer Synthesized CuInSi Thin Film
Authors: Luan Ping , Xie Jian Sheng , Li Jin Hua
Published: November 2011

Using magnetron sputtering technology, the CuInSi thin films were prepared by multilayer synthesized method. The structure of CuInSi films were detected by X-ray diffraction(XRD), the main crystal phase peak is at 2θ=42.458°; The resistivity of films were measured by SDY-4 four-probe meter; The conductive type of the films were tested by DLY-2 conductivity type testing instrument. The results show that the annealing temperature and time effect on the crystal resistivity and crystal structure greatly.
Performance Experiment of Natural Refrigerant Cascaded Refrigeration System
Authors: Ning Jing Hong , Liu Sheng Chun
Published: November 2011

In this paper, the performances of natural refrigerant R290/CO2 cascaded refrigeration system using R290 as high temperature cycle refrigerant and CO2 as low temperature cycle refrigerant were investigated experimentally. The test results show that both CO2 compressor and R290 compressor start up stably and present good running performance. The start-up power and start-up electric current of CO2 compressor are higher than that of R290 compressor. The COP (Coefficient of performance) of R290/CO2 cascaded system enhances with the increase of cooling water mass flow rate and the decrease of cooling water inlet temperature. The effect of CO2 refrigerant charge on the COP of cascaded system is obvious; however, the effect of R290 refrigerant charge on the COP of cascaded system is not obvious. Hence, the hermetic scroll type compressor is urgent to be developed and used in CO2 cycle for ensuring run safely and reliably, the value of cooling water mass flow rate and the cooling water inlet temperature must be selected reasonability for saving water resource and energy, as well as the charge amount must be determined by experiment for obtaining the optimum refrigerant charge.
Ultimate Slip between FRP and Concrete on their Interface
Authors: Yang Qi Fei , Meng Qing Lin
Published: November 2011

The ultimate relative slip between reinforced polymer (FRP) and concrete on their bond interface is a key parameter to analyze the debonding failure of FRP strengthened reinforced concrete beams. Lots of simple shear test specimens have been used to test the slip-shear stress relationship on the bond interface. However, the ultimate FRP-concrete slip has not been obtained directly from these experiments. Based on different theoretical considerations some ultimate slip values have been predicted. These values differ from one another to a large extent. The lower limit of the maximal slip between FRP and concrete in the span of strengthened beams is derived through a set of simple assumptions. Example calculations show that at loads exceeding 80% of the designed loads most maximal slips would reach 0.2mm or greater. The fact that most experimental beams at such loads do not exhibit debonding failure manifests that the ultimate slip should be greater than 0.2mm.
A Study on Interfacial Reaction and Titanium Distribution in Brazing Sapphire to Inconel 600 Using Cu/Ni Porous Composite
Authors: Zaharinie T. , Binti Yusof Farazila , Abdul Shukor Mohd Hamdi , Ariga T.
Published: November 2011

In this study, a Cu/Ni porous composite was introduced when brazing sapphire to Inconel 600 using a special active filler metal of BAg-8 + 2Ti. The aim of the research is to investigate the Ti distributionin the Cu/Niporous composite and braze joint. The brazing was carried out in brazingtemperature of 830°C for 30 minutes by a vacuum environment (10-4 Pa). The interface of braze joint/sapphire and braze joint/Inconel 600 were observed by an electron microscope followed by elements analyzing using SEM-EDS. The observation and analysis shows that there is a black and thin reaction layer at braze joint/sapphire interface and a non-uniform of reaction layer was formed at braze joint/Inconel 600 interface. The formation of reaction layer is influenced by thermodynamic activity of Ti during brazing.
Design of PID Algorithm Control System Based on DSP
Authors: Zhong Cong Jiu , Guan Zong An
Published: November 2011

Along with the industry and the motor control system performance and the intelligent request's unceasing enhancement, the PID control technology application is getting more and more widespread. This article use TMS320F2812 DSP of TI is a core, outside expands SRAM. This system control actuation closed loop direct current machine by the F2812, DSP controls electrical machinery's rotational speed and the direction through CPLD. It control electrical machinery's rotational speed by PID algorithm reaction. This system realized TMS320F2812 not to brush electrical machinery's control regarding the cocurrent, the main characteristic uses the digital PID controller, the original simulation PID controller hardware will realize the function realized with the software, it with simulated the PID controller to compare the merit is: Has the very strong flexibility, may test and experience the online adjustment parameter according to the experiment, may obtain the better control performance.
Effect of Ultrasonic Wave on Ni-P-Al2O3 Electroless Composite Coating on Magnesium Alloy
Authors: Fan Yong Zhe , Ma Li , Cao Xiao Ming
Published: November 2011

The coating was obtained by electroless plating Ni-P nano Al2O3 on AZ91D magnesium alloys under ultrasound wave. The metallographic microscope and micro sclerometer were used to characterize the structures and hardness of coating. The results showed that in the optimal conditions, ultrasonic electroless plating can increase the coating hardness value by 170HV and extend the coating corrosion resistance time by 130s; inorder to reach the same corrosion resistance time or hardness value, the temperature under ultrasonic decreases 20°C than that without ultrasonic wave; ultrasonic wave can improve the deposition rate, refine the grains and inhibit the nano particles to agglomerate.
Multi Objective Optimization of Noise and Vibration in Passenger Car Cabin by Using Goal Programming Approach
Authors: Junoh Ahmad Kadri , Mohd Nopiah Zulkifli , Wan Muhamad Wan Zuki Azman , Nor Mohd Jailani Mohd
Published: November 2011

Car cabin acoustical comfort is one of the main points which may attract the customers to purchase a new vehicle. Basically the noise in passenger car cabin is closely related to generated vibration in the vehicle system. The amount of discomfort depends to magnitude, frequency, direction and also the duration of exposed vibration in the cabin. The comfort of the driving influences driving performance. Generally the vibration is caused by two main sources: engine transmission and interaction between tyre and road surface. In this study the effects of vibration to noise in passenger car cabin were studied. Vehicle acoustical comfort index (VACI) was used to evaluate the noise annoyance level and vibration dose value (VDV) was used to evaluate the vibration level. According to the changes trend of noise and vibration level depending to engine speeds, goal programming model was used to optimise the noise annoyance level in passenger car cabin. At the end of study, a multi objective model successfully built to optimize the noise annoyance levels by looking the required vibration dose value at certain engine speeds. The results of the study might be useful for automotive researchers to provide technical method to optimize acoustical comfort in manufacturing of vehicles.
Diagnostic Dilemma Posed by Severe Pelvic Actinomycosis Associated with Prolonged Use of Copper Intrauterine Contraceptive Device
Authors: Bandyopadhyay Subhayu , Sinha Sanjay , Wui Chien Patrick Fan , Fleming Dawn
Published: November 2011

Actinomycosis has been recognized to be associated with the use of intrauterine contraceptive device. We are reporting a case where a patient with severe pelvic actinomycosis presented with the clinical picture of an ovarian tumour. A 44-year-old lady attended the A&E with progressively worsening lower abdominal pain. A computerized tomography (CT) scan showed the presence of a large pelvic mass, right hydronephrosis and prominent para-aortic lymph nodes and an elevated C-reactive proteine (CRP) and white cell count (WCC). When there was no improvement with antibiotic therapy, a laparotomy was performed, where bilateral tubo-ovarian abscess and dense adhesions were found. A subtotal hysterectomy, bilateral salpingoophorectomy and small bowel resection was performed. Histopathology of the specimen confirmed the diagnosis of actinomycosis. The case highlighted the diagnostic dilemma for ascertaining the nature of the pelvic mass in this patient. Due to its invasion of surrounding tissues and the formation of masses severe infection is often confused with an ovarian neoplasm.
A model to identify mathematics topics in MXit lingo to provide tutors quick access to supporting documentation
Authors: Butgereit Laurie , Botha Reinhardt A.
Published: November 2011

Dr MathTM is a mobile, online tutoring system where learners can use MXitTM on their mobile phones to receive help with their mathematics homework from volunteer tutors. These conversations between learners and Dr Math are held in MXit lingo. MXit lingo is a heavily abbreviated, English-like language that is evolving between users of mobile phones that communicate using MXit. The Dr Math project has been running since January 2007 and uses volunteer tutors who are mostly university students who readily understand and use MXit lingo. However, due to the large number of simultaneous conversations that the tutors are often involved in and the diversity of topics discussed, it would often be beneficial to provide assistance regarding the mathematics topic to the tutors. This article explains how the μ model identifies the mathematics topic in the conversation. The model identifies appropriate mathematics topics in just over 75% of conversations in a corpus of conversations identified to be about mathematics topics in the school curriculum.
Sociology, Hypocrisy, and Social Order
Authors: Erinosho Professor Layi
Published: November 2011

Abstract
L’imaginaire du Bureau et Les Usages du Fétiche au Gabon
Authors: Etoughé-Efé Jean-Emery
Published: November 2011

En nous appuyant sur les différents imaginaires qui concourent à l’interprétation de certains faits sociaux des peuples du Gabon, il apparaît que le bureau en tant que lieu de travail se nourrit d’un imaginaire. Celui-ci va de l’expression de la promotion sociale à une prétention à l’acquisition du pouvoir. Cet imaginaire semble trouver ses origines dans la période coloniale oùle travail du bureau était la fonction des “Blancs” qui maîtrisaient l’écriture alors que le travail manuel était strictement réservé aux populations indigènes. Depuis cette époque, le bureau detravail fait l’objet de toutes les attentions et convoitises. Et dès lors qu’ils sont installés, certains occupants s’efforcent, par tous les moyens, de le conserver. Les stratégies de conservation et de protection contre les agressions diverses sont visibles à travers les usages des fétiches. Ceux-ci sont souvent représentés par certains objets qui ont une importance culturelle sur le plan local. Ces éléments de défense et de protection dans l’espace de travail semblent le transformer en domaine d’appropriation au point de faire du bureau une zone interdite et avoir tendance à le confisquer pour soi.
Situating South Africa’s Past, Present and Future
Authors: Forje John W.
Published: November 2011

Abstract
The rise to prominence of Artemisia annual the transformation of a Chinese plant to a global pharmaceutical
Authors: Caroline Meier zu Biesen
Published: November 2011

This paper focuses on the transformation of a recently promoted medicinal plant namedArtemisia annua L. For over 2000 years, the Chinese have used A. annua as a herbal tea preparation against malaria. Pharmacological studies led to the isolation of artemisinin as the principal anti-malarial compound. Since 2001, the World health Organisation (WhO) has recommended artemisinin-based combined therapies (‘ACTs’) for the treatment of malaria – novartis is the leading actor to extract the compound in tablet form. in the 1990s, A. annua was introduced to Tanzania. Beside the local plant-based promotion of Artemisia-tea as an efficient, inexpensive natural practice to treat malaria, Tanzania hosts influential actors who seek to commercialise the plant. By following the biography of the Chinese medicinal plant, its global transfer, production, marketing, distribution, consumption, and its transformation to a highly demanded commodity, the paper critically reveals the dialectics and reciprocities between different actors and their relation to existing powerful reference systems (such as WhO, Pharmaceutical industry).
Of Remedies and Poisons: Recreational Use of Antiretroviral Drugs in the Social Imagination of South African Carers
Authors: Fiona Larkan  , Brian Van Wyk  , Jamie Saris
Published: November 2011

During an ethnographic study of barriers to, and compliance with, antiretroviral (ARv) treat- ment in the South Africa’s West Coast region, our team came across a general sense amongst heath careproviders that there was a lively illicit trade in antiretroviral medications. in itself, this is seen to be a barrier to adherence for many of their patients whose medication is traded to, or stolen by, drug dealers. independent anecdotal evidence is emerging about this trade, though there has been little hard data verifying the existence of a recreational market for ARvs. While there are rumours that efavirenz (some of whose side effects are hallucinogenic) is being used in the manufacture of crystal methamphetamine (locally ‘tik’), such reports, in themselves, do not seem able to explain the ubiquity (and the confidence) of the belief in this trade amongst the health care providers with whom we have interacted. This paper explores aspects of the off-label trade of ARvs (as we have come to know it) and, as importantly, how rumor and knowledge of this trade has gained increasing currency in the social imagination of health and social care workers. This, we argue, could precipitate a real crisis in the Government’s public rollout programme.
A Question of Power: Co-Determination and Trade Union Capacity
Authors: Buhlungu Sakhela
Published: November 2011

Abstract
Thinking About African Urban Management in an Era of Globalisation
Authors: Abdou Maliq Simone
Published: November 2011

Abstract
Des historiens et des histoires, pourquoi faire? L'historiographie africaine entre l'Etat et les Communautés
Authors: Mamadou Diouf
Published: November 2011

Abstract
L'idée de 'sciences sociales
Authors: Achille Mbembe
Published: November 2011

Abstract
An Overview of the Performance of the East African Economies since 1985: Implications for the New Initiative on East African Co-operation
Authors: Peter Kimemia
Published: November 2011

Abstract
C.R.D. Halisi. Black Political Thought in the Making of South African Democracy. Bloomington and Indianapolis: Indiana University Press.
Authors: Neville Alexander
Published: November 2011

Abstract
Patrick Bond. Cities of Gold, Townships of Coal: Essays on South Africa's New Urban Crisis. Trenton and Asmara: Africa World Press, Inc. 2000.
Authors: Caroline O'Reilly  , Geoffrey Wood
Published: November 2011

Abstract
Developing Mechanisms to Promote South-South Research in Science and Technology: the Case of the Southern African Development Community
Authors: Michael J. Kahn
Published: November 2011

The African continent has struggled ta develop an indigenous agenda for science and technology research and development. Despite efforts since the 1960s, the results have been less than satisfactory. In the southern region, the Southern African Development Community (SADC) has attempted to play a coordinating rote for science and technology, but is widely regarded ta have been unsuccessjul in this venture. Although many countries in the SADC region have elevated the science and tech­ nology (S&T) function to Ministerial level, the linkages between S&T, government, industry and higher education are tenuous atbest. There hasbeen much talk of policy driven development, but little in the way ofaction. This paper will sketch the history of S&T development in the SADC region and in particular the interplay between the local agenda and that of the advanced industrial countries. lt will highlight the difficul­ ties ofconducting research against imbalances in resources and exper­ tise by considering an initiative of the Department of Arts, Culture, Science and Technology that seeks to foster research cooperation between South Africa and the SADC region. The paper will explore the relations between and among state research institutions, higher educa­ tion and industry in SADC and considers possibilitiesfor local research co-operation.
From liberation movements to governments On political culture in Southern Africa
Authors: Henning Melber
Published: November 2011

Abstract
Better infection than hunger’. A study of illness perceptions with special focus on urinary schistosomiasis in Northern Tanzania
Authors: Beth Maina Ahlberg  , Rose Mwangi  , Gabriel Poggensee  , Hermann Feldmeier H  , Ingela Krantz
Published: November 2011

This paper is about how a community in Northern Tanzania experiences and reasons around urinary schistosomiasis and more specifically female genital schistosomiasis or schistosomiasis of the reproductive tract. As a disease, female genital schistosomiasis presents itself with a variety of symptoms which neither the affected woman nor the medical professionals usually recognise as schistosomiasis. The study therefore focused on symptom recognition, the question being whether women living in an endemic area can distinguish symptoms of urinary and genital schistosomiasis from those of other diseases presenting in similar ways. Data were generated using a combination of qualitative methods including observation, individual interviews and focus group discussions with diverse categories of people. All the research participants were aware of the link between water and infection. Because the disease is associated with farming, the main livelihood, there was a strong feeling among the research participants that treatment, whether in hospital or by traditional medicine could not effect permanent cure. Re-infection was considered inevitable and as schistosomiasis was said to be less poisonous than malaria, it was felt there was little choice between being infected and having food. Making sense of the symptoms was considered moreover difficult although women and men said they could tell whether blood in urine was due to urinary schistosomiasis or other conditions such as sexually transmitted diseases which present similar symptoms. The similarity of symptoms was said to be problematic also because of the sensitivity and stigma in sexually transmitted diseases. Urinary schistosomiasis is therefore a complex health problem and for any effective control there is clearly a need to grasp this complexity.
Denial and violence:Paradoxes in men’s perspectives to premarital sex and pregnancy in Rural Zimbabwe
Authors: Jeremiah Chikovore  , Gunilla Lindmark  , Beth Maina Ahlberg
Published: November 2011

This paper describes the perspectives of men on premarital sex and pregnancy in rural Zimbabwe. It is based on data collected using three qualitative methods including focus group discussions and individual interviews among men and women, and self-generated questions and statements among school youth. The paper illuminates the paradoxes of denial and violence implicit in the way men speak: as relatives on the one hand and as and as partners on the other regarding pregnancy in girls.The men say they react violently to premarital pregnancy, but neither do they tolerate sexual activity, or allow contraceptive information or service for unmarried daughters and sisters, even though their accounts paradoxically suggest that sexual abuse of young girls is rampant. Despite denying them preventive service and information, men speaking as partners expect girls to have knowledge about sexuality, the menstrual cycle and pregnancy. They blame their girlfriends for getting pregnant, despite indications from the accounts of the girls that it is male partners who pressure the girls into unprotected sexual activity. In suchcircumstances, the girls say the pregnancy may translate into unsafe, induced abortion. These are complexities at the micro-level that need to be understood for any meaningful programme to improve adolescent sexual and reproductive health.
Gone but not forgotten': Chieftaincy, Accountability and State Audit in Ghana, 1993-99
Authors: E Kojo Sakyi
Published: November 2011

Abstract
Note on Alcohol Consumption and Sexual Behaviour of Youths in Botswana
Authors: Eugene K. Campbell
Published: November 2011

Abstract
Gender and Family life in Angola: Some aspects of the post-war conflict concerning displaced persons
Authors: João Baptista
Published: November 2011

Abstract
Putting Oil First? Some Ethnographic Aspects of Petro leum-related Land Use Contro versies in NigeriaPutting Oil First? Some Ethnographic Aspects of Petro leum-related Land Use Contro versies in Nigeria
Authors: Wilson Akpan
Published: November 2011

This arti cle exam ines, based on recent ethnographic data, one of the lesser known pro cesses through which petro leum oper ations sus tain social con flict in Nige ria. Focussing on what has come to be termed ‘em inent domain abuse’ by the inter na tional envi ron men tal jus tice com munity, the arti cle reveals the char ac ter of petro leum oper ations in a num berof com mu ni ties in Nige ria’s oil-producing region. The arti cle relates the practices of the trans national oil com panies, the dis position of the reg ulatory author ities, and the oppositional dis courses of ordi nary peo ple in the oil com mu ni ties to the laws gov erning land use and min eral own ership in the coun try.
Long-range transport of terrain-induced turbulence from high-resolution numerical simulations
Authors: Katurji M. , Zhong S. , Zawar-Reza P.
Published: November 2011

Abstract. Over complex terrain, an important question is how various topographic features may generate or alter wind turbulence and how far the influence can be extended downstream. Current measurement technology limits the capability in providing a long-range snapshot of turbulence as atmospheric eddies travel over terrain, interact with each other, change their productive and dissipative properties, and are then observed tens of kilometers downstream of their source. In this study, we investigate through high-resolution numerical simulations the atmospheric transport of terrain-generated turbulence in an atmosphere that is neutrally stratified. The simulations are two-dimensional with an isotropic spatial resolution of 15 m and run to a quasi-steady state. They are designed in such a way to allow an examination of the effects of a bell-shaped experimental hill with varying height and aspect ratio on turbulence properties generated by another hill 20 km upstream. Averaged fields of the turbulent kinetic energy (TKE) imply that terrain could have a large influence on velocity perturbations at least 30H (H is the terrain height) upstream and downstream of the terrain, with the largest effect happening in the area of the largest pressure perturbations. The results also show that downstream of the terrain the TKE fields are sensitive to the terrain's aspect ratio with larger enhancement in turbulence by higher aspect ratio, while upstream there is a suppression of turbulence that does not appear to be sensitive to the terrain aspect ratio. Instantaneous vorticity fields shows very detailed flow structures that resemble a multitude of eddy scales dynamically interacting while shearing oppositely paired vortices. The knowledge of the turbulence production and modifications by topography from these high-resolution simulations can be helpful in understanding long-range terrain-induced turbulence and improving turbulence parameterizations used in lower resolution weather prediction models.
Global risk of radioactive fallout after nuclear reactor accidents
Authors: Lelieveld J. , Kunkel D. , Lawrence M. G.
Published: November 2011

Abstract. Reactor core meltdowns of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents, using particulate 137Cs and gaseous 131I as proxies for the fallout. It appears that previously the occurrence of major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a core melt of any nuclear power plant worldwide, more than 90% of emitted 137Cs would be transported beyond 50km and about 50% beyond 1000 km distance. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human deposition exposure are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in southern Asia where a core melt can subject 55 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.