Force feedback pushing scheme for micromanipulation applications

Pushing micro-objects using point contact provides more flexibility and less complexity compared to pick and place operation. Due to the fact that in micro-world surface forces are much more dominant than inertial forces and these forces are distributed unevenly, pushing through the center of mass of the micro-object may not yield a pure translational motion. In order to translate a micro-object, the line of pushing should pass through the center of friction. In this paper, a semi-autonomous scheme based on hybrid vision/force feedback procedure is proposed to push micro-objects with human assistance using a custom built tele-micromanipulation setup to achieve translational motion. In the semi-autonomous pushing process, velocity controlled pushing with force feedback is realized along x-axis by the human operator while y-axis orientation is undertaken automatically using visual feedback. This way the desired line of pushing for the micro-object is controlled to pass through the varying center of friction. Experimental results are shown to prove nano-Newton range force sensing, scaled bilateral teleoperation with force feedback and snapshot of pushing operation

Influence of temperature on the performance of a full-scale activated sludge process operated at varying solids retention times whilst treating municipal sewage

In this study, the solid retention time (SRT) was varied with the ambient temperature for a full-scale municipal activated sludge plant with capacity of 200,000 PE (Population Equivalent) located in a humid sub-tropical environment. The effects of ambient temperature on treatment performance were investigated. Off-line samples were collected and analyzed from the treatment plant. The actual temperature variation during the study period was divided into three overlapping ranges and the SRT was adjusted accordingly with temperature in order to achieve the desired effluent quality. The plant’s observed effluent quality and thereby its overall removal efficiency was evaluated in terms of measuring standard biochemical parameters. The results indicate that significant improvement in effluent quality can be obtained by applying the variable SRT (5–7 days) dependent on temperature variation

Discrete-time sliding mode control of high precision linear drive using frictional model

The paper deals with high precision motion control of linear drive system. The accuracy and behavior of the linear drive system are highly affected by the non-linear frictional component compromising of stiction, viscous and stribeck effect present in the system especially in the vicinity of zero velocity. In order to achieve the high accuracy and motion it is mandatory to drive our system with low velocity resulting in many non linear phenomena like tracking error, limit cycles and undesired stick-slip motion etc. This paper discuss the design and implementation of discrete time sliding mode control along with the implementation of dynamic frictional model in order to estimate and compensate the disturbance arising due to frictional component. Experimental results are presented to illustrate the effectiveness and achievable control performance of the proposed scheme

Semi-autonomous scheme for pushing micro-objects

-In many microassembly applications, it is often desirable to position and orient polygonal micro-objects lying on a planar surface. Pushing micro-objects using point contact provides more flexibility and less complexity compared to pick and place operation. Due to the fact that in micro-world surface forces are much more dominant than inertial forces and these forces are distributed unevenly, pushing through the center of mass of the micro-object will not yield a pure translational motion. In order to translate a micro-object, the line of pushing should pass through the center of friction. In this paper, a semi-autonomous scheme based on hybrid vision/force feedback is proposed to push microobjects with human assistance using a custom built telemicromanipulation setup to achieve pure translational motion. The pushing operation is divided into two concurrent processes: In one process human operator who acts as an impedance controller alters the velocity of the pusher while in contact with the micro-object through scaled bilateral teleoperation with force feedback. In the other process, the desired line of pushing for the micro-object is determined continuously using visual feedback procedures so that it always passes through the varying center of friction. Experimental results are demonstrated to prove nanoNewton range force sensing, scaled bilateral teleoperation with force feedback and pushing microobjects

Discrete sliding mode control of piezo actuator in nano-scale range

In this paper Discrete Sliding Mode Control (SMC) of Piezo actuator is demonstrated in order to achieve a very high accuracy in Nano-scale with the desired dynamics. In spite of the fast dynamics of the Piezo actuator the problem of chattering is eliminated with the SMC control structure. The Piezo actuator suffers from hysteresis loop which is the inherent property and it gives rise to the dominant non-linearity in the system. The proposed SMC control structure has been proved to deliver chattering free motion along with the compensation of the non linearity present due to hysteresis in the system. To further enhance the accuracy of the closed loop system and to be invariant to changes in the plant parameters a robust disturbance observer is designed on SMC framework by taking into consideration the lumped nominal plant parameters. Experimental results for closed loop position are presented in order to verify the Nano-scale accuracy

Minimally invasive posterior spinal fusion in unstable thoracolumbar

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Medicine in the branch of Orthopaedic Surgery Johannesburg, 2017Background Unstable Thoracolumbar spinal fractures are conventionally treated by open reduction and internal fixation. This involves extensive mobilization of paraspinal muscles, which in turn leads to long-term disability in the form of chronic backache. One of the reasons fractures are stabilized is to prevent kyphotic deformity. Posterior lumbar stabilization done through a minimally invasive technique can achieve the same result as the open technique at the expense of less mobilization of the paraspinal muscles. Aim of the study The aim of the study was to assess the effectiveness of minimally invasive posterior spinal fixation in unstable Thoraco-lumbar fractures in our setting at Charlotte Maxeke Academic Hospital. Objectives To assess the effectiveness of Minimally Invasive Spine Surgery over a short term of minimum of 12 months regarding: Maintaining the correction of fracture kyphosis, Re-operations and Any serious Adverse Events Methodology This was a prospective interventional pilot study. Fractures were classified according to the AO comprehensive system. AO Comprehensive classification fractures A3, B1, B2, C1 and C2 were considered suitable for this technique. Pre-operative, immediate post-operative and one year follow up Cobb’s angles of fracture kyphosis were measured on plain lateral x-rays. Any Serious Adverse Events (SAE) that may have required re-operations were recorded over the minimum of 12 months follow up. Results Twenty patients met the inclusion criteria for this study. Post-operative follow up ranged between 12 and 22 months. There were 14 males and 6 females. The age ranged between 16 years to 54 years with mean of 33.9 years. L1 was the most commonly fractured vertebra. Eleven out of 20 patients sustained fracture of L1, 6 patients had fracture of L2 whereas 3 patients sustained fracture of T12. The AO classification types included one B1, five B2, seven C1 and seven C2 fractures. The pre-operative Cobb’s angle ranged from 7 degrees to 38 degrees with mean of 21.2 degrees. The immediate post-operative Cobb’s angle ranged between zero degrees to 16 degrees with mean of 8.3 degrees. The last follow up Cobb’s angle ranged between zero degrees to 21 degrees with a mean of 10.7 degrees. The loss of correction of fracture kyphosis ranged between zero degrees to 6 degrees with a mean of 2.4 degrees. The post-operative Cobb’s angle was maintained. There was no deterioration of pre-operative neurological status. There was no serious adverse event requiring a re-operation. Conclusion Minimally Invasive Posterior Spinal stabilization for thoracolumbar fractures had an acceptable outcome in our hands in appropriately selected cases. The average loss of correction of 2.4 degrees was in keeping with that found in open technique as well as MIS at other centers. While the number is less, this procedure can be recommended for well selected patients where skills are available.MT201

Enhancement of Project Performance through Risk Management and Monitoring & Evaluation with Moderating Role of Project Manager Decisional Skills

The major issue of concern right now is how to run a project successfully and efficiently. The ultimate goal is to achieve a project performance and information technology is becoming noticeably progressively centered on projects because of market dynamism and rivalry. There might be a few elements that can influence project performance; however, this research concentrates on risk management (RM), Monitoring & evaluation (M&E), project manager decisional skills (DS) and its effect on project performance (PP). Researches prove the significance of risk management at any level or any type of organizations and monitoring & evaluation is a key project performance factors. The research is based on empirical studies and quantitative research based on the questionnaire. 239 IT sector employees was taken to examine the relationships between risk management to project performance, Monitoring & evaluation to project performance and project manager decisional skills to project performance. The moderating role of project manager decisional skills also examined in RM-PP and ME-PP relationship. 4 hypotheses were being tested in which all of them comes out to be significant and correlated positively. Result shows that factors have significant impact on the project performance.  The results show that risk management and monitoring & evaluation contribute in the project performance. Results have also shown that project management decisional skills moderate the relation between risk management and monitoring & evaluation on project performance. Practical implications of the study are presented based on the results. Keywords: M&E, Risk Management, Project Manager Decisional skills, Project Performance.

Role of Brand Characteristics and Its Impact on Consumer Buying Behavior

Social classes can affect the behavior of consumers towards the product or services with respect to the features of product like brand image price and quality of services Consumer buying behavior is highly dependent on two variables income and brand characteristics Sometimes consumers are not willing to buy a product or avail a service but for his her status symbol the buying behavior of that consumer gets affected here the social status retention shows the impact of brand characteristics on different social classes buying behavior Globally there are three main classes I e Upper Middle and Lower classes Each class of people have different behavior attitude preferences interest standard of living and income power these are the variations that segments the individuals personality into distinct classes which are mentioned above This study analyzed that how brand characteristics like brand image price and quality can affect the buying behavior of middle and lower social classes for cell phone purchas

Impact of Socialization on Organizational Commitment of Employees: A Case Study of Private Degree Colleges in Nowshehra, District, KPK

Implementations of HR practices carry a significant weightage towards organization’s success. The study was focused to find out the impact of socialization process on organizational commitment of employees working in private degree colleges. 200 hundred questionnaires were distributed among the teaching staff of degree colleges using convenient sampling technique. 126 properly filled questionnaires forming a response rate of 63% were analyzed to get meaningful results. The results of the study showed that socialization process was found to have significant impact on organizational commitment of employees

The Effect of Buyer-supplier Partnership and Information Integration on Supply Chain Performance: An Experience from Chinese Manufacturing Industry

Coordination, collaboration, and cooperation are often used in business term to enhance productivity and performance, in this way the partnership with supplier and information integration always play an important role in supply chain. This study investigates the effect of Buyer-supplier partnership and information integration on supply chain performance. The study also elaborates the development of trust and guanxi between suppliers and buyers for better business environment in supply chains. This study uses structural equation modeling to analyze data collected from 218 Chinese manufacturing industries. The Buyer-supplier relationship significantly affects trust and guanxi, which subsequently influences two elements of information integration, namely, quality information and real-time information. We found that Buyer-supplier partnership and information integration have a significant effect on supply performance. Furthermore, we found that trust and guanxi are pivotal role in sustaining better relationship between supplier and business for long run and growt