bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on DPC-SVM Rectifier Based on Power Feedforward
Authors: Zhao Zhang Fei , Tan Guo Jun , Liu Meng , Chen Guo Zhen , Wang Zheng
Published: November 2011

In this paper, on the basis of the mathematic model of the three-level PWM rectifier, a power feedforward based control strategy is proposed combining with direct power control with space vector modulation (DPC-SVM) control principle. Feedforward control can reduce or even eliminate the impact on the system causing by load disturbance to improve dynamic performance. The simulation results show that the control method makes the system response speed faster and the dynamic performance better, it largely improved the system rectifier capacity against load disturbances.
PID Controll of Single Neuron for Switched Reluctance Motors Based on RBF Neural Network
Authors: Qi Shu Fen , Wang Guo Dong
Published: November 2011

This paper presents a novel approach of single neuron PID control for switched reluctance motors based on RBF neural network on-line identification. The method is adjusted to the nonlinearity of switched reluctance motors, and use the single neurons capable of self-learning and self-adaption to form the single neuron adaptive controller of switched reluctance motors. It not only has simple structure and strong robustness, but but can adapt to environmental changes. Also we construct a RBF network system to identify the system online, and to build its online reference model, using a single neuron controller to achieve self-learning of its parameters, in order to achieve their online adjustment, and to obtain better control effect.
Calculation on Thermal Field of a Doubly-Fed Induction Generator with Axial-Radial Ventilation Cooling System
Authors: Zhang Zhi Qiang , Ge Bao Jun
Published: November 2011

A type of doubly-fed induction generator with air-water cooling and axial-radial ventilation cooling system is proposed in this paper. A half-axial segment stator-rotor coupled thermal field 3D model of the doubly-fed induction generator prototype is built with some properly assumptions, according to its symmetry in electromagnetic structure and cooling system. Stator-rotor coupled thermal field distribution of prototype is calculated under rated operating. The influence of water mass-flow and number of cooling-ribs to the thermal field distribution is also studied with the 3D model.
Application Study of Active Disturbance Rejection Control Technology
Authors: Shi Xin Xin , Chang Si Qin
Published: November 2011

Active disturbance rejection control technology and its application to trajectory tracking control of a linear actuator are presented in this paper. Working principle of each part of this control technology is given, and parameter tuning method is discussed which helps control engineers to use this technology well. In order to test the performance of active disturbance rejection control technology, a sinusoidal trajectory tracking control system of a linear actuator is constructed. Simulation and experimental results show that the introduced control technology can achieve small tracking error at low velocity where friction is the main disturbance. Active disturbance rejection control technology provides a good choice for control engineers in actual industry applications with its simple structure, convenience to use and excellent performance.
Simulation of Silicon Solar Cell Using PC1D
Authors: Jiang Chuan , Li Tian Ze , Zhang Xia , Hou Luan
Published: November 2011

PC1D software, which was developed by the University of New South Wales, has been used to simulate photovoltaic properties of crystalline semiconductor devices. The paper focuses on the simulation of silicon solar cell by PC1D. The simulation of silicon solar cell is carried out by setting up key parameters, which include device area, thickness, band gap, etc. Several important characteristics of silicon solar cells are obtained by simulation.
Geometrical Error Analysis of Cold Forged AUV Propeller Blade Using Optical Measurement Method
Authors: Abdullah A.B. , Sapuan S.M. , Samad Z. , Khaleed H. M. T. , Aziz N.A.
Published: November 2011

Accuracy is the key issue in the precision forging. Geometric and dimension errors are the two significant defects found in most of near net or net shape manufacturing process. It becomes more critical for complex part such as an AUV propeller blade. In this study, geometric error was quantified by comparing the blade profile obtained from nominal geometry of the blade and the profile constructed by commercial optical method namely Alicona system.
Excitation Control Strategy of Brushless Doubly-Fed Generator for Variable Speed Constant Frequency Wind Power System
Authors: Zhang Feng Ge , Li He , Jin Shi
Published: November 2011

This paper focuses on brushless doubly-fed generator (BDFG) control system used in variable speed constant frequency (VSCF) wind power generation. For maximum wind energy capture, a direct torque control (DTC) strategy is proposed based on the relationship between the maximum absorption power and speed of BDFG. The simulation results of the control system show that the maximum power can be tracked by a quick adjustment of the torque and the feasibility of the control system is verified using Matlab. Furthermore, considering the control system platform with DSP as the core, the control system software program and hardware circuit is designed, including main program and interrupt program processes.
A Design Methodology for Lithium-Ion Battery Management System and its Application to an Autonomous Underwater Vehicle
Authors: Shen Chao , Wan Lei
Published: November 2011

Battery management system (BMS) in autonomous underwater vehicle (AUV) not only can measure the main parameters of battery packs such as current, voltage, and temperature, but also estimate the state of charge (SOC) of battery packs. This paper proposes a broad approach for the design of battery management system. The new design can improve the cycle life and safety capability. With the model well designed, the parameters required are obtained and the SOC estimation is completed. Extended Kalman filter (EKF) was chosen to make the last estimate with the reliable battery model which was used to the non-linear system to estimate SOC and suitable for AUV applications. The experiments results prove that the data measured by battery management system have high precision and reliability. The estimated error of SOC was also small, which was better than other approaches for estimate.
Design of Photon Counter in PCS Nano-Particle Size Analyzer
Authors: Wang Xian Qiang , Shen Jin , Liu Wei , Zhu Xin Jun
Published: November 2011

In view of the extremely weak scattered light in PCS nano-particle size analyzer, a photon counter consisting of a PMT, amplifier, discriminator and pulse counter is designed. A double-counter structure is adopted in pulse counter in order to realize “glue” counter. The standard polystyrene particles are measured by using this counter, and the correlation of the collected photons was implemented. The experimental results show that the counter can reach the precision of PCS nano-particle size analyzer.
The Performance Optimization Design of High Frequency and High Voltage Transformer of Electronic Beam Welder
Authors: Fan Sheng Wen , Zhao Yun
Published: November 2011

High-frequency digital inverter power supply has the advantages of small, no noise, high efficiency, small ripp- le, and perfect protection, therefore, is gradually replacing the traditional electron beam welder which uses the 400Hz frequency generator. However, with more high frequency of the power supply, the design of the transformer used by the high-frequency high-voltage electron beam welding becomes difficult. Therefore, this paper put forward a diversified transformer mode and a voltage doubling rectifier circuit, which were used to reduce the transformer turns ratio, thus reducing the topology of the transformer distribution para- meters. Accordingly, a special high-frequency high-voltage electron beam welding tank is designed. Tests show that the set of performance indicators of the fuel tank meets the design goals to meet the actual needs of welding process.
Implementation of a DirectDrive Technology Realization DC-Coupled Output on Video-Output Circuits
Authors: Lv Cheng Xiang
Published: November 2011

An AC-coupled output includes a series capacitor, while a DC-coupled output does not. This article explains the reasons for choosing either an AC-coupled or a DC-coupled video output. Maxim's DirectDrive video technology eliminates large output coupling capacitors and sets the output video black level near ground, which has the characteristics of an AC-coupled connection but the simplicity of a DC-coupled connection, is introduced. The working principle of Capacitive Charge Pump, is introduced too. Take the case of MAX9532 analyses the main choice of the components and parts in peripheral circuit, it has listed the precautions in the circuit design.
Modeling and Testing a Screw Expander Integrated into a Trilateral Flash Cycle
Authors: Wang Zhi Gang , He Shan , Li Jian Xin , Song Guo Jun
Published: November 2011

Trilateral Flash Cycle (TFC) is particularly suitable for recovering energy from low-grade heat source. This paper presented a new mathematical model for calculating the performance of a twin screw expander integrated into a TFC working with organic components. The geometric parameters related to the rotation angle of male rotor e.g. groove volume, suction and discharge port area, leakage area etc were used in the model. The combination effects of internal leakage through five paths, oil injection, gas-oil heat transfer and refrigerant property were taken into account. The sensitivity of single parameter was also analyzed. To verify the model and the calculated p-φ indicator diagram, experimental recording of the diagram of twin screw expander was performed. The results of theoretical calculation were in good agreement with the experimental data, which indicated that the model in the present paper could be used as a powerful tool for performance prediction and product development.
Study on Simulation of Path Plan of Parallel Grinding for Wedge Aspheric
Authors: Jiang Chen , Guo Yin Biao , Zhang Ning Ning , Han Chun Guang
Published: November 2011

In order to ensure the machining precision of wedge nonaxisymmetric aspheric lens, a parallel grinding method is designed using a clamp with adjustable gradient. Based on the machining method, three path plans of machining are put forward. Simulation results show that the three methods have their particular advantages according to the different requirement of machining
Fuzzy Control of Automobile ECBS on Varying Pavement
Authors: Sun Ren Yun , Wang Bo , Zhan Yong Fu
Published: November 2011

The Fuzzy control method in an automobile Electronic Control Braking System (ECBS) on varying pavement is studied. According to the characteristics of an automobile ECBS which adapts to the varying pavement, the ECBS fuzzy control system is established. The ECBS fuzzy controller based on slip is designed. When the automobile is braking on uniform pavement and varying pavement, the computer simulation is fulfilled for the deceleration threshold value control and the slip fuzzy control of the automobile ECBS by using MATLAB/Simulink. The results show that the automobile ECBS using fuzzy control can obtain better fundamental braking performance on varying pavement, wheel locking doesn’t appear, both braking distance and braking time are short, the fluctuation of the wheel periphery velocity is little and smooth, its braking performance is obviously better than the deceleration threshold value control.
Research of Simulation Parameters of Oil Field Distribution Network Based on Grey Prediction
Authors: Liu Run Hua , Cui Yan
Published: November 2011

In the view of the shortcomings of high load fluctuation and complex operating parameters changes, the paper proposes a method, which combines the improved GM (1,1) Grey forecasting model and mathematical simulation for pumping operation, in order to simulate the operating parameters of oil field distribution network. By the metabolism ways of 4-days equal dimension and weighted average, these methods have improved the prediction accuracy. Based on the predicted results and the rand function in MATLAB, the operating parameters of oil field distribution network will be determined by power flow calculation. The example results show that the prediction accuracy and simulation results have achieved the expected goal.
Fuzzy Controller Design for Multi-Legged Robot
Authors: Tang Zhi Yong , Zhong Hai Xiao , Pei Zhong Cai , Bu Yan Hao
Published: November 2011

In this paper, we propose a mechanical structure for multi-legged robot. Referring the request of control system, we also made a proper choice on driving means. After dynamics analysis on a single leg of the robot, we make a simulation using ADAMS and get how the torque of each joint is changing when the robot is walking. The model of DC motor is established for the control system. Fuzzy PID controller was used to get real-time response and high accuracy of control system.
Development of Service Platform for Machine Tool Fixture Design and Manufacture
Authors: Xiang Bei Ping
Published: November 2011

Based on analysis of characteristics and develop trend of fixture design, the functional structure of service platform for networked manufacturing has been put forward. Information integrating technology, networked manufacturing service technology, and collaborative work technology has been researched in detail. The feasibility and practicality of functional structure of service platform for fixture design and manufacture has been verified by development and preliminary application of the service system.
Finite Element Analysis of Fiber-Reinforced Iron-Boron Alloy
Authors: Zhang Yun , Yang Wei , Wu Jian Jun
Published: November 2011

The Finite element analysis model of fiber-reinforced iron-boron alloy was established in this article. Effects of the fiber properties on residual thermal stress and tensile strength of the composites were calculated. Composites with different fibers were calculated and comparatively studied.
Switched Reluctance Motor Drive System Model and Simulation Based on ANSYS and SIMULINK
Authors: Yan Xiu Ke , He Xiao Wei
Published: November 2011

This paper provided a kind of method to analyze the flux of the switched reluctance motor(SRM) at different rotor position and current by ANSYS. Then the derivative of static inductance with rotor position angle was computed by cubic spline interpolating function, on this basis, the non-linear inductance model with the lookup table of Switched reluctance motor drive system(SRD) was established by SIMULINK. The dynamic properties of SRM was studied comprehensively. Through a prototype simulation of three phase 12/8 SRM, analyzing the characteristics of torque and current to establish reasonable control strategy at the different turn-on angle and turn-off angle. Simulation results showed that the SRM model was reasonable and efficacious, a new idea was proposed for design and debugging of the actual motor control system.
Electromagnetic Force Modelling for Hybrid Magnetic Bearing
Authors: Cao Yang , Zong Ming , Zhang Jing
Published: November 2011

In this paper, a novel structure of hybrid magnetic bearing with PM bias and inductance displacement sensor is proposed. The operating principle of the hybrid magnetic bearing with PM bias is introduced. The Electromagnetic Force Model is built in the paper, which is useful for the hybrid magnetic bearing control. An example is given. The analysis of finite element method shows that the structure of the hybrid magnetic bearing with PM bias proposed in the paper is feasible and the calculation method for hybrid magnetic circuit is correct.
Detection of Electromagnetic Pulse Induced Hazard on Electroexplosive Device Based on Optical-Fiber Fluorescence
Authors: Liu Lan Shu , Zhang Wen Song , Zhu Xiang Ping
Published: November 2011

The electroexplosive devices(EED) are widely used in the core system of rocket, missile and nuclear weapons. Hazard analysis and measurement of electromagnetic pulse is of great importance to the security and reliability of EED. In this article, an optical-fiber fluorescence temperature sensor is proposed for analyzing hazard induced by electromagnetic pulse of EED. The temperature of EED can be measured through the fluorescence lifetime, then the induced current is obtained, and thereby the electromagnetic pulse induced hazard can be draw. The experiments show that, the set-up of this proposal can works with high precision and fast response, and immune to the electromagnetic interference.
Electromagnetic Compatibility Analysis of Carbon Fiber Cabin Struck by Lightning in the Aircraft
Authors: Guo Dan Dan , Su Dong Lin , Zhao Xiao Ying , Deng Li Peng , Chen You Feng
Published: November 2011

Aircraft is more light than usual because of using the material of carbon fiber, which can make aircraft lighter than metal materials. But the shielding effectiveness of carbon fiber is worse than metal materials. First, This paper explains the direct effect and the indirect effect which aircraft suffer of the lightning strike. And then this paper analysis and imitates the carbon fiber cabin struck by lightning. And then, at two circumstance of indirect effect, this paper gives the result of electric field, magnetic field and surface current. Finally, this paper gives some advice for defending outside the carbon fiber cabin and electromagnetic compatibility (EMC) inside the carbon fiber cabin.
Attitude Control of Rigid Body Using Sliding Mode Control
Authors: Bian Hui Hui , Wang Zhong Hua
Published: November 2011

In this paper, a sliding mode controller is developed based on the modified rodrigues parameters. Modified rodrigues parameters can avoid the singularity in kinematic equations and realize less parameters setting. Finally, the numerical simulation results show that the method is effective.
The Variable Speed Direct Drive Permanent Magnet Synchronous Wind Power System Used on Matrix Converter
Authors: Yang Bo , Zeng Guang , Zhong Yan Ru
Published: November 2011

A voltage control strategy of the converter inverter-stage is proposed for the variable speed direct drive wind power system which consists with the two stage matrix converter (TSMC) and the permanent magnet synchronous generator (PMSG). In this control strategy, the inverter-stage voltage is controlled by the adjusted of inverter-stage modulation ratio M. For two cases, which is strong wind speed and weak wind speed, the ways that is decrease M and increase M are used and obtain the wide wind speed capture range. The resulted of simulation and experiment show that this way can make the voltage stabled. The performance of the converter implement this control strategy is still as same as the dual PWM converter and the wind power system preserve the feature of the wide wind speed capture range. So this way is effective and feasible to some extent.
A Signal Quality Monitoring Based on Least-Squares for Global Navigation Satellite System
Authors: Chen Hai Long , Zhu Yan Bo , Xue Rui
Published: November 2011

Signal Quality Monitoring (SQM) proposes to detect anomalous Global Navigation Satellite System (GNSS) signal distortions primarily through the using the multi-correlator receivers. These receivers employ three or more correlator pairs per channel-each slaved to tracking pairs. Then the measurements from each channel are transformed to form detection metrics. However, previously such some metrics were only simple algebraic combinations of the measurements and did not describe truly the characteristics of the correlation peak. This paper introduced a metric which uses measurements of each channel to fit the quadratic model with least-squares method to monitor the GNSS signal.
Analysis and Discussion of the Influence Factors of the Wind Power
Authors: Li Guo Jian , Hu Yan Jun
Published: November 2011

Wind as a renewable energy, is typical of clean energy, and wind power generation has good social and environmental benefits, which has developed rapidly in worldwide. In this paper, the problems of China's wind power industry and the world wind power industry experience are discussed. The distribution of resources for wind energy, wind energy resource assessment, monitoring and forecasting system, wind industry, policy influencing factors are detailed analysis, and based on China conditions for its development were discussed.
Manufacturing Execution System Based on the Soda Ash Industry
Authors: Cheng Su E.
Published: November 2011

The essay introduced the design ideas and functional features of the manufacturing execution system based on the soda ash industry, with a view of helping manufacturing enterprises to solve practical problems in their production and management, and providing basis for their decision making.
Determination of Trace Level Oxytetracycline and Influences of Coexisting Pollutants on its Sorption by Three Kinds of Sludge
Authors: Huang Man Hong , Chen Liang , Chen Dong Hui , Yang Yu Dong
Published: November 2011

Strong anion exchange (SAX) columns and oasis HLB cartridges were combined to extract trace level oxytetracycline(OTC) and high performance liquid chromatography(HPLC) UV-detector were used to measure it in wastewater sample. The effect of mobile phase was investigated. Under the best analysis conditions, linear calibration equations were established for OTC. The linearity were in the range of 0.1-10g/mL, Correlation coefficient (R2) is about 0.9997. The recovery factors ranged from 82-92% with a relative standard deviation of 4.8-6.4%.Lab-scale experiments were conducted to investigate the sorption behavior of OTC by anaerobic sludge. Starch in the mixed liquor can decrease the adsorption capacity of OTC.
Interfacial Microstructure and Strength of Friction Welding of Steel Tube to Aluminium Tube Plate Using an External Tool
Authors: Muthukumaran S. , Kumar C. Vijaya , Kumaran S. Senthil , Pradeep A.
Published: November 2011

Joining of dissimilar materials is of increasing interest for a wide range of industrial applications like nuclear, thermal power. The automotive industry, in particular, views dissimilar materials joining as a gateway for the implementation of lightweight materials. Friction welding of tube to tube plate using an external tool is an innovative friction welding process and is capable of producing high quality leak proof weld joints. In the present study, friction welding of steel tube to commercial aluminum tube plate using an external tool with and without tube projection have been performed. The joints were evaluated by mechanical testing and metallurgical analysis. The results of bonding interface hardness and joint strength reveal that steel tube with projection are better than the steel tube without projection.
Dexterous Robot’s Finger Actuated by Pneumatic Artificial Muscle
Authors: Guo Bing Jing , Wang Kai
Published: November 2011

Through the structural analysis of hand, using mechatronics ideas, robot fingers based on Pneumatic Muscle Actuators (PMA) is designed and manufactured. Referring to the proportion of manual hand, the finger has three degrees of freedom. The far and middle finger joints are coupled of steel wire transmission mechanism, while the middle finger knuckle and the root are driven by a pair of artificial muscles. In order to realize the feedback control of displacement and the tactile force, the finger’s three joints are installed with three R24HS potentiometer and the fingertip is installed with the touch force sensor. The finger design integrates with mechanical structure, sensing, control and driving system. It achieves the integration and modularization in a maximum extent and completes the full theoretical support and experimental verification for the next step integration design of the flexible bionic robot hand.
Study on PMV Index Forecasting Method Based on Fuzzy C-Means Clustering
Authors: Zhang Chun Cheng , Chen Xiang Guang , Xu Yuan Qing
Published: November 2011

In order to improve the forecasting accuracy of indoor thermal comfort, the basic principle of fuzzy c-means clustering algorithm (FCM) and support vector machines (SVM) is analyzed. A kind of SVM forecasting method based on FCM data preprocess is proposed in this paper. The large data sets can be divided into multiple mixed groups and each group is represented by a single regression model using the proposed method. The support vector machines based on fuzzy c-means clustering algorithm (FCM+SVM) and the BP neural network based on fuzzy c-means clustering algorithm (FCM+BPNN) are respectively applied to forecast PMV index. The experimental results demonstrate that the FCM+SVM method has better forecasting accuracy compared with FCM+BPNN method.
RVE Based Numerical Evaluation on Effective Mechanical Properties of Composite with Randomly Distributed Multi-Phase Inclusions
Authors: Li Chun , Chen Lei , Qiao Li
Published: November 2011

The purpose of this paper is to evaluate the effective mechanical properties of composite ceramic with randomly distributed multi-phase inclusions. The RVE finite element subcell technique based on numerical homogenization theory is used to separate the multi-phase composite into the layered unit cell models which are generated by a modified random sequential adsorption algorithm (RSA). The numerical results are also compared and verified with experiment data.
Preparation of Modified Cu-Antibacterial White Carbon Black by Microwave Drying
Authors: Zhang Bin , Tang Xiao Ning
Published: November 2011

This paper investigated the synthesis and characterization of the Cu-antibacterial White Carbon Black modified by electrolyte, surfactant, and organic solvent. The sol-gel method was used to prepare the White Carbon Black carrier. Cu2+ was selected to be the antibacterial ion, and sodium nitrite (electrolyte), sodium dodecylbenzene sulfonate (surfactant), ethanol (organic solvent) was selected to be the modifiers. They were synthesized on the White Carbon Black carrier. These as-synthesized modified antibacterial materials were characterized by inductively coupled plasma, particle size measurement instrument and enumeration tests (Escherichia coli as experimental bacterium). The result showed that the amount of antibacterial ions and bacteriostasis rate of modified Cu-antibacterial White Carbon Black are higher than those of the common Cu-antibacterial White Carbon Black. In addition, the particle sizes of modified samples can be extended down to 7 µm with a narrow size distribution. Other advantages of modified Cu-antibacterial White Carbon Black are short drying time (only 5 min by microwave), good thermal and light stability.
Study on Morphological Structure and Application of Ag-La-Inorganic Antibacterial Material Dying by Microwave
Authors: Zhang Bin , Tang Xiao Ning
Published: November 2011

This paper investigated the morphological structure and application of the Ag-La-inorganic antibacterial material. The sol-gel method was used to prepare the carrier: White Carbon Black. Silver ion was selected to be the antibacterial ion, and lanthanum nitrate was selected to be the additive. The morphological structure and application of this new inorganic antibacterial material were characterized by inductively coupled plasma (ICP), scanning electron microscope (SEM) techniques, energy dispersive spectrum (EDS) analysis, antibacterial activity test (Escherichia coli as experimental bacterium) and application experiment. Results showed that the amount of antibacterial ion of the Ag-La-inorganic antibacterial material was higher than that of the general Ag-inorganic antibacterial material. And its bacteriostasis rate was also higher than that of the general Ag-inorganic antibacterial material. Other advantages of this material are its loose and dispersive structure. In addition, this new inorganic antibacterial material showed promising result in rubber.
A Study on Ammonia Nitrogen, Phosphorus and Organic Pollutants Removal of Zeolites by Salt Modification
Authors: Lin Hai , Zhao Zhi Ying , Jiang Le Yong , Wei Wei
Published: November 2011

In this study, the zeolites were treated by NaCl and FeCl3 as an active agent, combined with calcination modification. We studied the ammonia nitrogen (NH3-N) and phosphorus (P) removal of the modified zeolites. The results showed that concentration of NaCl and FeCl3 affected NH3-N and P removal of Secondary sewage effluent greatly. The optimal concentrations of NaCl and FeCl3 were 2.0% and 0.4%. At this condition, the NH3-N and P removal rate of zeolites reached the peak. Application experiments revealed that NH3-N removal rate reached 80.9%, P removal rate reached 83.4%, and COD removal rate reached 96.0%, when the dosage of modified zeolites was 3.0g/L and adsorption duration was 2h for Secondary sewage effluent with 6.0mg/L NH3-N concentration and 1.5mg/L P concentration. After the treatment, the NH3-N and P concentration met Reclaimed Water Quality Standards. The adsorption capability of modified zeolites was better when the pH ranged from 3 to 6. The reason of using NaCl+FeCl3 was that Na+ could exchange the NH3-N in the effluent; Fe3+was able to combine with PO43- in the sewage and formed precipitate; and Fe3+ could also oxidize the organic pollutants.
A Stochastic Difference Equation with Stationary Noise on Groups
Authors: Chandiraraj Robinson Edward Raja
Published: November 2011

We consider the stochastic difference equation on a locally compact group G, where is an automorphism of G, ξk are given G-valued random variables and ηk are unknown G-valued random variables. This equation was considered by Tsirelson and Yor on a one-dimensional torus. We consider the case when ξk have a common law μ and prove that if G is a distal group and is a distal automorphism of G and if the equation has a solution, then extremal solutions of the equation are in one-to-one correspondence with points on the coset space K\G for some compact subgroup K of G such that μ is supported on for any z in the support of μ. We also provide a necessary and sufficient condition for the existence of solutions to the equation.
Crisis, Capital, Compromise: Mining and Empowerment in Zimbabwe
Authors: Saunders Richard
Published: November 2011

Abstract
Prendre en compte les échelles: Le mouvement patriotique et la construction de ‘l’autochtone’ en Côte d’Ivoire
Authors: Arnaut Karel
Published: November 2011

Abstract
Local perspectives on transnational relations of Cameroonian migrants
Authors: Pelican Michaela
Published: November 2011

Abstract
More Hands in Complex ART Delivery? Experiences from the Expert Clients Initiative in Rural Uganda
Authors: Kyakuwa Margaret
Published: November 2011

This paper aims to analytically describe the experiences and outcomes of involving peopleliving with HIV/AIDS in clinical care of HIV/AIDS within the healthcare clinic in a poorlyresourced setting. With HIV/AIDS treatment finally available in poorly resourced settings,there was huge number of people in need of clinical care. As a result, professional health workersbecame overwhelmed by the demand for treatment and care. Consequently, this called for anew way to handle the rising numbers and needs of clients at the health clinic level so as tominimise the burden of care on the health professionals. An 18 months ethnographic studywas conducted between 2005 to 2007 with professional medical workers (including Doctors,nurses and counsellors, clinicians), ART clients and with family care givers of ART clients, ata Health center IV-HIV clinic in a rural district in Uganda. The result shows that the scalingup of ART and subsequent introduction of Expert Clients as a new care arrangement withinthe health clinic has opened up the clinical space as some pseudo space where at least in principle, the patient has a voice in care with various outcomes.
Dancing Around the Same Spot? Land Reform and NGOs in Zimbabwe – ! e Case of SOS Children’s Villages
Authors: Helliker K D
Published: November 2011

This paper discusses the rural-based operations of an international NGO in Mashonaland Central province, Zimbabwe. The aim is to highlight the contingent variation of NGO practices within deftned limits. It does this through ‘thick  description’ of the NGO of focus, the SOS Children’s Village, and compares its ‘handling‘ of the transforming countryside with the re- sponse of two other NGOs. It concludes by suggesting some conceptual points in understanding organizational dispositions of NGOs.
A Drum’s Trans-Atlantic Journey from Africa to the Americas and Back after the end of Slavery: Annobonese and Fernandino musical cultures.
Authors: Aranzadi Isabela de
Published: November 2011

Musical instruments are an intrinsic part of culture accompanying people as an essential fac- torin shaping the identity preserved through memory. In equatorial guinea there are some ethnic and social groups: fang, Bubi, ndowe, etc. It is in relation to the Annobonese and the fernandinosmusical culture, that the concept of “Return trip to Africa” becomes meaning- ful. This paperdiscusses this focusing on instruments such as cumbé, kunkí, and dances such as cumbé or bonkó, which constitute an African legacy that has returned and has become a part of equatorial guinea’s musical culture. The paper’s main point is that the identity given by the African elements has remained active until today.
Re-imagining South African Cultural Studies
Authors: Sarah Nuttall  , Cheryl Ann Michael
Published: November 2011

Abstract
L'Afrique dans la Science des Relations Internationales: Notes Introductives et Provisoires pour une Sociologie de la Connaissance Internationaliste
Authors: Luc Sindjoun
Published: November 2011

Historiciser la science des relations internationales dans son rapport à l'objet « Afrique » est une démarche intellectuelle qui permet d'accéder au principe de la construction de la spécificité africaine et du changement des manières de penser celle-ci. La spécificité africaine est dans une large mesure le fait d'une science des relations internationales qui s'est construite en méconnaissant l'Afrique ; l'épreuve de la mondialisation, tout en bouleversant les cadres de pensée, reconfigure l'Afrique dans les relations internationales.
Income Distribution and Inequality: gender, labour market status and macro-economic policy
Authors: Jimi 0. Adesina
Published: November 2011

This paper examines the impacts of gender and labour market status on income distribution and inequality. This is against the background of the macroeconomic policy instruments deployed since 1982 in Nigeria. The study is based on data from a sample survey of 473 households (with 2,412 members) drawn from the urban, semi-urban, and rural areas in southwestern Nigeria. The study shows a complex relationship between the key variables. The relationship between gender and the size distribu­ tion of personal or per capita household income is statistically signifi­ cant. However, among heads of household, the relationship is not significant. Income inequality is more pronounced amongfemale-headed households. Labour market status also yields a complex picture. The relationship between labour market status and the size distribution of income (personal and per capita income) is significant. Households whose heads are in wage employment are worse off than those with heads in self-employment. When gender is loaded, labour market status remains statistically significant for the size distribution of income. Income inequality has worsened under adjustment; but at a much deeper rate than some other studies suggest. Urban inequality is deeper than is gen­ erally acknowledged, and those in wage employment are particularly hard hit, while owners of capital have done quite well. Finally, while vul­nerability among women in low pay has increased, the income inequality is as much a function of class as it is of gender.
Gender masked or self-inflicted pain: female circumcision, eradication and persistence in Central Kenya
Authors: Beth Maina Ahlberg  , Wangui Njau  , Karanja Kiiru  , Lngela Krantz
Published: November 2011

Abstract
Civil Society and the Democratic Experience in Kenya: A Review of Constitution-Making from the Middle: Civil Society and Transition Politics in Kenya, 1992-1997, by Willy Mutunga. Sareat & Mwengo, Nairobi, 1999
Authors: Godwin R. Murunga
Published: November 2011

Abstract
For Many are Called but Few are Chosen": Globalisation and Popular Disenchantment in Africa
Authors: Francis B. Nyamnjoh
Published: November 2011

Abstract
African Media, Information Providers¹ and Emigrants as Collaborative Nodes in Virtual Social Networks
Authors: Anthony A. Olorunnisola
Published: November 2011

This paper proposes that the Internet offers African media and informa­ tion providers the opportunity to elevate their current engagement to that of "content providers" to African emigrants in the diaspora. The paper finds evidence in the intercultural adjustment and social networks litera­ ture to support the feasibility of such an interaction. Further, a composite profile of African emigrants in the diaspora allows the discussion of ways in which they represent 'virtual' communities whose on- and off-line dis­ courses can be enriched by African content providers 'participation. The proposed engagement finds African content providers and emigrants interacting as active nodes in computer-mediated social networks. Among other possibilities, the paper views the evolvement as one that should enable African media organizations to widen their domestic margin of political freedom. The paper's propositions have both policy and research implications.
Thinking Through the Crisis of Democratisation in Kenya: A Response to Adar and Murunga
Authors: Rok Ajulu
Published: November 2011

Abstract
The Scholarly Journal in the Production and Dissemination of Knowledge on Africa: Exploring Some Issues for the Future
Authors: Sulaiman A. Adebowale
Published: November 2011

abstract
African Knowledge and Ideas and the African Information Society
Authors: John C. Afele
Published: November 2011

abstract
Challenging Subjects: Gender and Power in African Contexts
Authors: Amina Mama
Published: November 2011

abstract
Community Attitudes Towards Casinos and the Estimated Magnitude of Problem Gambling: The Mpumalanga Case
Authors: A.A. Ligthelm
Published: November 2011

abstract
Gender Inequality: Still a Critical Issue in the Development of Rural KwaZulu-Natal
Authors: P.S.M. Ndimande
Published: November 2011

abstract
Power, Education, And Identity in post-colonial Zimbabwe the fate of King Lobengula Of Matabeleland
Authors: Bjiorn Lindgren
Published: November 2011

Abstract
Monopoly Politikos : How Botswana's opposition Parties have helped sustain One-Party Dominance
Authors: Onalenna Doo Selolwane
Published: November 2011

The main thesis of this paper is that Botswana 's opposition parties are accountable for their failure to provide the voting public with a meaning­ ful alternative to the ruling Botswana Democratic Party. While conced­ ing the explanatory importance of other factors such as resource capacity, this paper departs from conventional wisdom by focusing on the strategic and ideological weaknesses of the opposition parties. It argues that the opposition parties made a number of strategic errors which ren­ dered them electorally unattractive before they could establish their legitimacy as contenders for government power. To break the monopoly of power that the ruling party has so far enjoyed, Botswana 's opposition must transform itself into a meaningful competitor and govern­ ment-in-waiting. To do that they must (a) demonstrate that they have a viable, alternative economic management strategy to better satisfy the interests of a diverse voting public and (b) develop broad based political strategies targeting the diverse voting public to build voter confidence in the capability of the party as a possible government. The ruling party's track record of four decades of sustained economic growth leaves a for­ midable challenge to the opposition.
Beyond Democratic constitutionalism On the Twofold meaning of Democracy and Democratisation
Authors: Lars Rudebeck
Published: November 2011

Abstract
Kiraitu Murunig. 2000 In the mad of politics. Nairobi. Acacia Stantex Publishers
Authors: Godwin R. Murunga
Published: November 2011

Abstract
Traditional Cultural Practices of Imparting Sex Education and the Fight against HIV/AIDS: The Case of Initiation Ceremonies for Girls in Zambia
Authors: Augustus K. Kapungwe
Published: November 2011

The Human Immuno-Deficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) have become a major health problem in Zambia. Because of the threat HIV/AIDS poses to the nation, the government of Zambia embarked on a public health campaign aimed at combating the scourge. However, so far this campaign has predominantly been conducted through modern channels of information communication. The overall objective of this study was to explore the role one particular traditional channel of sex information communication, the initiation ceremony of girls, could play in disseminating information to combat HIV/AIDS. Data were collected from five residential areas using systematic random sampling. Overall, the study concludes that although there is no evidence to directly link initiation ceremonies with HIV/AIDS, indirectly today’s initiation ceremonies enhance the spread of HIV/AIDS. But it is encouraging to point out that, given the demonstrated willingness of the majority of initiators to learn more about HIV/AIDS, the identified inadequacies in initiation ceremonies can be removed so thatthis channel is used effectively in the fight against the disease.
On HIV, Sex and Respect: Local-Global Discourse Encounters among the Datoga ofTanzania
Authors: Astrid Blystad
Published: November 2011

The topic of concern in this paper is the manner in which global/y con­structed AIDS and HIV control messages are received by the Datoga of Tanzania. The text will rejlect on how messages on safe and healthy sex in national/global HIV campaigns are not in accord with Datoga concepts and practices aimed at ensuring proper sexuality and fertility, and the troubled eflècts of such dissonance. In an attempt to grasp the dynamics at work in the encounters between HIV prevention messages and local sexual concepts and practices, some central Foucauldian questions are asked, such as how and why sexual activity is constituted as a moral domain among Datoga. The substantial Datoga preoccupation with pro­creation is located at the heart of the argument. The discussion will reveal how Datoga sexuality is becoming increasingly troubled, compounding and accentuating the already severe uncertainties experienced in every­day lifè. The argument is o.ffered that unless communication about HIVIAIDS takes the cultural contexts that shape risk behaviour into account, such campaigns will fall on deaf ears, and may cause more su.f fering rather than less.
Mother's Milk, An Ambiguous Blessing in the Bra of AIDS: The Case of'the Chagga in Kilimanjaro
Authors: Karen Marie Moland
Published: November 2011

HIVIAIDS has renewed the need for a critical interpretation of hreast­feeding in social and cultural terms. The issue that this study addresses is how medically informed knowledge o_f HIV transmission through breast­feeding is interpreted and transformed in a local rural community in Kilimaryaro Region in northern Tanzania. The paper explores the articu­lation between a medical discourse on risk and a local dis course on moth­erhood which infrJrms the choice of infant jèeding method. Jt dis eusses the complexities involved in making an appropriate decision on breasiféed­ing, and argues that breas(feeding must be understood as close/y tied to the cultural elaboration of the female body and of motherhood. lt shows that the body of the mother and the body ()/'the newborn child are subject to close scrutiny and local diagnostic processes. Not breasifèeding is not only perceived as a significant fàilure of motherhood, but also rais es sus­picion of a likely HIV positive status on the part of the mother.
Concerns about Child Subject Research in Botswana: A Call for Estab lishing Struc tures and Guide lines that Protect Children
Authors: Tapologo Maundeni  , Lisa Lopez Le vers
Published: November 2011

Abstract
Dust resuspension under weak wind conditions: direct observations and model
Authors: Chkhetiani O. G. , Gledzer E. B. , Artamonova M. S. , Iordanskii M. A.
Published: November 2011

Abstract. Here we report the results of the direct observations of fine scale mineral dust aerosol carried out over extensive sand areas in desertificated lands of Kalmykia in 2007, 2009 and 2010 under conditions of weak wind and strong heating of the surface with near absence of saltation processes. Measurements show that the fine mineral dust aerosol in the chosen region constitutes a considerable fraction of the entire air aerosol in the atmospheric surface layer (in terms of both the number of particles and their mass). Data of fine aerosol mass concentrations are treated on the basis of physical model estimates obtained for fluid dynamic parameters in the viscous thermal boundary layer near the ground surface. The deviations of mass concentrations from background are linked to temperature drop in the thermal layer near the surface and the value of friction velocity.
Description and validation of an AOT product over land at the 0.6 μm channel of the SEVIRI sensor onboard MSG
Authors: Bernard E. , Moulin C. , Ramon D. , Jolivet D. , Riedi J. , Nicolas J.-M.
Published: November 2011

Abstract. The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard Meteosat Second Generation (MSG) launched in 2003 by EUMETSAT is dedicated to the Nowcasting applications and Numerical Weather Prediction and to the provision of observations for climate monitoring and research. We use the data in visible and near infrared (NIR) channels to derive the aerosol optical thickness (AOT) over land. The algorithm is based on the assumption that the top of the atmosphere (TOA) reflectance increases with the aerosol load. This is a reasonable assumption except in case of absorbing aerosols above bright surfaces. We assume that the minimum in a 14-days time series of the TOA reflectance is, once corrected from gaseous scattering and absorption, representative of the surface reflectance. The AOT and the aerosol model (a set of 5 models is used), are retrieved by matching the simulated TOA reflectance with the TOA reflectances measured by SEVIRI in its visible and NIR spectral bands. The high temporal resolution of the data acquisition by SEVIRI allows to retrieve the AOT every 15 min with a spatial resolution of 3 km at sub-satellite point, over the entire SEVIRI disk covering Europe, Africa and part of South America. The resulting AOT, a level 2 product at the native temporal and spatial SEVIRI resolutions, is presented and evaluated in this paper. The AOT has been validated using ground based measurements from AErosol RObotic NETwork (AERONET), a sun-photometer network, focusing over Europe for 3 months in 2006. The SEVIRI estimates correlate well with the AERONET measurements, r = 0.64, with a slight overestimate, bias = −0.017. The sources of errors are mainly the cloud contamination and the bad estimation of the surface reflectance. The temporal evolutions exhibited by both datasets show very good agreement which allows to conclude that the AOT Level 2 product from SEVIRI can be used to quantify the aerosol content and to monitor its daily evolution with a high temporal frequency. The comparison with daily maps of Moderate Resolution Imaging Spectroradiometer (MODIS) AOT level 3 product shows qualitative good agreement in the retrieved geographic patterns of AOT. Given the high spatial and temporal resolutions obtained with this approach, our results have clear potential for applications ranging from air quality monitoring to climate studies. This paper presents a first evaluation and validation of the derived AOT over Europe in order to document the overall quality of a product that will be made publicly available to the users of the aforementioned research communities.