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Sensorless control of brushless permanent magnet motors
No full textIn this thesis, a sensorless control method of permanent magnet synchronous machines (PMSMs), whose machine neutral points are accessible, for all speeds and at standstill is proposed, researched and developed. The sensorless method is called Direct Flux Control (DFC). The different voltages between a machine neutral point and an artificial neutral point are required for the DFC method. These voltages are used to extract flux linkage signals as voltage signals, which are necessary to approximate electrical rotor positions by manipulating the flux linkage signals. The DFC method is a continuous exciting method and based on an asymmetry characteristic and machine saliencies.The DFC method is validated by implementing on both software and hardware implementation. A cooperative simulation with Simplorer for the driving circuit and programming the DFC and Maxwell for doing finite element analysis with the machine design is selected as the software simulation environment. The machine model and the DFC method are validated and implemented. Moreover, the influences of different machine structures are also investigated in order to improve the quality of the measured voltages.The hardware implementation has been employed on two test benches, i.e. for small machines and for big machines. Both test benches use a TriCore PXROS microcontroller platform to implement the DFC method. There are several PMSMs, both salient poles and non-salient poles, which are used to validate the DFC method. The flux linkage signals are also analyzed. The approximation of the flux linkage signal is derived and proposed. A technique to remove the uncertainty of the calculated electrical rotor position based on the inductance characteristics has been found and implemented. The electrical rotor position estimation method has been developed based on the found flux linkage signal approximation function and analyzed by comparing with other calculation techniques.Moreover, the calculated electrical rotor position is taken into account to either assure or show the relation with the exact rotor position by testing on the hardware environment. The closed loop speed sensorless control of PMSMs with DFC is presented and executed by using the assured calculated electrical rotor position to perform the DFC capability.This thesis has been done in the Electric Machines, Drives and Power Electronics Laboratory, South Westphalia University of Applied Sciences, Soest, Germany
UK construction site safety: discourses of enforcement and engagement
No full textDevelopments in safety management on large UK construction sites have seen a paradigm shift from enforcement-based systems to safety-culture programmes, which seek to engage with the workforce to create fully cooperative and safety-conscious sites. Founded in social constructionism, recent research sought out the master discourses of safety on large UK construction sites through the examination of safety signage, talk around safety and safety documentation. Two of the most prominent discourses of safety on sites were found to be safety as enforcement and safety as engagement, reflecting the change in safety management strategies. These discourses were found to be interrelated in their constructions of safety, yet also varied in their associations with practice, responsibility, social interactions and the management hierarchy of the sites. These findings develop the current understanding of safety found on sites, with relation to the hierarchical structures of safety management and the discourses of enforcement and engagement in practice. The findings have significance for the safety practices of large UK contractors in developing and improving their safety-culture programmes, as well as suggesting potential new directions in the academic research of safety in construction
Contribution of textiles to medical and healthcare products and developing innovative medical devices
No full textThe application of medical textiles used in woundcare nursing, implants, and healthcare and hygiene products has been discussed. The production and properties of biodegradable polysaccharide fibres obtained from natural sources, such as alginate, chitin/chitosan, collagen, catgut and branan ferulate, have been highlighted. Speciality medical polymeric fibres used for producing wound dressings, bandages and textile scaffolds for tissue culture have been presented. In addition, the difficulties encountered by elderly people due to venous leg ulcers and a specific research and development programme carried out at the University of Bolton in developing novel padding and compression bandages for the treatment of venous leg ulcers have also been critically discussed. It is observed that the developed padding bandages meet most of the criteria required for ideal bandages and have excellent pressure distribution property around the limb over the existing commercial padding bandages. The pressure profiling of the novel padding bandages in two-layer, three-layer and four-layer systems has been studied
Cluster Fractal Model - A Flexible Network Model for Future Power Systems
No full textA grid integration ratio of decentralized energy conversion systems (ECSs) in combination with renewable energy sources (RESs) has been recently increased in order to build up sustainable electrical power supply systems. Due to those changes, it can be predicted that the decentralized systems will change the conventional top-down power flow process to be the bidirectional process. Then the power flow can be reversed from distribution level to transmission level. To handle those significant changes, the cluster power systems approach has been developed and proposed to be the future of power systems. The strategy is to cluster the power systems in several areas, called cluster area. And the smart grid cluster controller (SGCC) unit is announced as a smart controller to operate the cluster based on each area. Presently, SGCC control functions have been published and proved that the SGCC can give an opportunity to establish control function down to local level. On the other hand, the cluster systems structure must be thoroughly considered to complete the clustering approach. Therefore, the cluster fractal model is proposed in this paper as a flexible and an adaptive model to organize the cluster network structure. According to fractal model, the internal structure of each cluster can be described by using the same network model. And the linkage to another cluster is allocated by the hierarchical system; superordinate, ordinate and sub-ordinate level. To this point of view, the fractal model has the flexibility to model the network of clustering power systems and ensures the bottom-up approach strategy. With the fractal model of cluster network structure and the SGCC, the cluster power systems philosophy will finally simplify the way for future smart gird
Arthriting: exploring the relationship between identity and medicines use, and to identify the contribution of medicines and pharmacy services, for the care of young people with arthritis: Final report
No full textExamining the roles of victim-perpetrator relationship and emotional closeness in judgments toward a depicted child sexual abuse case
No full textThe current study investigated the impact that respondent gender, victim– perpetrator relationship, and the level of emotional closeness had on attributions in a hypothetical child sexual abuse case. A total of 160 university students read a hypothetical scenario depicting a female child sexually abused by an adult male. The perpetrator was either the victim’s biological father or her stepfather, with this relationship described as being either emotionally close or emotionally distant. Respondents read one of four (2 victim–perpetrator relationship × 2 emotional closeness) scenarios before completing 26 attribution items pertaining to credibility, blame, and severity.Principle components analysis yielded five factors, namely victim credibility, mother culpability, perpetrator culpability, assault severity, and victim culpability. Multivariate analysis of covariance—controlling for respondent (Caucasian vs. non-Caucasian) ethnicity—revealed, as predicted, significant main effects for respondent gender, victim–perpetrator relationship, and emotional closeness. In general, females assigned more provictim/ antiperpetrator/antimother attributions than males. Results were also suggested that both victim–perpetrator relationship and emotional closeness influence attributions made toward the victim, perpetrator, and nonoffending mother.Methodological issues and suggestions for future work are also discussed
Remarkable lives – Jane Aldred in conversation with Jerome Carson
No full textPurpose
– The purpose of this paper is to provide a profile of Jane Aldred.
Design/methodology/approach
– Jane provides a short biography and is then interviewed by Jerome. Areas covered in the interview include how mental health services can be improved, diversity, recovery academies, the social model, medication and philosophy.
Findings
– Jane has used her own journey of recovery as a basis for developing a course called “Supporting the Recovery Process”. Her work as a Day Service Champion, has given her insight into how services can best promote recovery and the importance of the social model of disability. She is now completing a postgraduate teaching qualification and is involved with a new Recovery Academy.
Originality/value
– Encouraging people to be proactive in their treatment and valuing their accomplishments and strengths are core elements in Jane's approach. People should be treated with kindness and respect with less focus on risk management
Sensors based on SAW and FBAR technologies
No full textOver the last few years a number of sensing platforms are being investigated for their use in drug development, microanalysis or medical diagnosis. Lab-on-a-chip (LOC) are devices integrating more than one laboratory functions on a single device chip of a very small size, and typically consist of two main components: microfluidic handling systems and sensors. The physical mechanisms that are generally used for microfluidics and sensors are different, hence making the integration of these components difficult and costly. In this work we present a lab-on-a-chip system based on surface acoustic waves (for fluid manipulation) and film bulk acoustic resonators (for sensing). Coupling surface acoustic waves into liquids induces acoustic streaming and motion of micro-droplets, whilst it is well-known that bulk acoustic waves can be used to fabricate microgravimetric sensors. Both technologies offer exceptional sensitivity and can be fabricated from piezoelectric thin films deposited on Si substrates, reducing the fabrication time/cost of the LOC devices
Bipolar resistive switching characteristics of low temperature grown ZnO thin films by plasma-enhanced atomic layer deposition
No full textZnO films deposited by plasma-enhanced atomic layer deposition (PEALD) have been used to investigate resistive memory behavior. The bipolar resistance switching properties were observed in the Al/PEALD-ZnO/Pt devices. The resistance ratio for the high and low resistance states (HRS/LRS) is more than 103, better than ZnO devices deposited by other methods. The dominant conduction mechanisms of HRS and LRS are trap-controlled space charge limited current and Ohmic behavior, respectively. The resistive switching behavior is induced upon the formation/disruption of conducting filaments. This study demonstrated that the PEALD-ZnO films have better properties for the application in 3D resistance random access memory