The University of Sheffield is a research university in the city of Sheffield in South Yorkshire, England. It received its royal charter in 1905 as successor to Sheffield Medical School and University College of Sheffield . As one of the original red brick universities, it is also a member of the prestigious Russell Group of research-intensive universities.The University of Sheffield is widely recognized as a leading research and teaching university in the UK and in the world. In 2014, QS World University Rankings placed Sheffield as the 66th university worldwide and 12th in the UK. In 2011, Sheffield was named 'University of the Year' in the Times Higher Education awards. The latest Times Higher Education Student Experience Survey 2014 ranked the University of Sheffield 1st for student experience, social life, university facilities and accommodation, among other categories.The university had more than 17000 undergraduate and around 9000 postgraduate students in 2012. Its annual income for 2012-13 was £479.8 million, with an expenditure of £465.0 million, resulting in a surplus of £14.8 million. Wikipedia.
Zhong Q.-C.,University of Sheffield
IEEE Transactions on Industrial Electronics
In this paper, the inherent limitations of the conventional droop control scheme are revealed. It has been proven that parallel-operated inverters should have the same per-unit impedance in order for them to share the load accurately in proportion to their power ratings when the conventional droop control scheme is adopted. The droop controllers should also generate the same voltage set-point for the inverters. Both conditions are difficult to meet in practice, which results in errors in proportional load sharing. An improved droop controller is then proposed to achieve accurate proportional load sharing without meeting these two requirements and to reduce the load voltage drop due to the load effect and the droop effect. The load voltage can be maintained within the desired range around the rated value. The strategy is robust against numerical errors, disturbances, noises, feeder impedance, parameter drifts and component mismatches. The only sharing error, which is quantified in this paper, comes from the error in measuring the load voltage. When there are errors in the voltage measured, a fundamental tradeoff between the voltage drop and the sharing accuracy appears. It has also been explained that, in order to avoid errors in power sharing, the global settings of the rated voltage and frequency should be accurate. Experimental results are provided to verify the analysis and design. © 2012 IEEE. Source
De Palma M.,Ecole Polytechnique Federale de Lausanne |
Lewis C.E.,University of Sheffield
Tumor-associated macrophages (TAMs) promote key processes in tumor progression, like angiogenesis, immunosuppression, invasion, and metastasis. Increasing studies have also shown that TAMs can either enhance or antagonize the antitumor efficacy of cytotoxic chemotherapy, cancer-cell targeting antibodies, and immunotherapeutic agents-depending on the type of treatment and tumor model. TAMs also drive reparative mechanisms in tumors after radiotherapy or treatment with vascular-targeting agents. Here, we discuss the biological significance and clinical implications of these findings, with an emphasis on novel approaches that effectively target TAMs to increase the efficacy of such therapies. © 2013 Elsevier Inc. Source
Webb T.J.,University of Sheffield
Trends in Ecology and Evolution
The extent to which similar ecological processes operate on land and in the sea has been much debated, with apparently 'fundamental' differences often disappearing when appropriate comparisons are made. However, marine and terrestrial ecology have developed as largely separate intellectual endeavours, which has hampered the search for general patterns and mechanisms. Here, I argue that marine-terrestrial comparative studies can be extremely useful at uncovering mechanisms when they explicitly consider those facets of the environment that are important to a particular hypothesis. Furthermore, the binary 'marine-terrestrial' division misses many opportunities for more interesting comparisons, several of which I highlight here. Increasing the flow of concepts, hypotheses, and data between marine and terrestrial ecologists is essential to reveal those differences that really are important. © 2012 Elsevier Ltd. Source
Qatar University and University of Sheffield | Date: 2014-07-18
The reinforced polymer composites from recycled plastic are polymer blends made from recycled polymers that are reinforced with glass fibers and mica. In particular, the reinforced polymer composites are blends of recycled low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) with a mica filler that are reinforced with glass fibers, where the low-density polyethylene forms between 30 wt % and 35 wt % of the composite, the high-density polyethylene forms between 15 wt % and 17.5 wt % of the composite, the polypropylene forms between 15 wt % and 17.5 wt % of the composite, the glass fibers form between 15 wt % and 40 wt % of the composite, and the mica forms up to 15 wt % of the structural element. The resultant reinforced polymer composite has a relatively high heat deflection temperature, good mechanical properties (such as increased stiffness and strength), improved thermal stability, and is cost effective to manufacture.
University of Sheffield | Date: 2014-03-24
A group of fixtures for thin-walled shell/cylindrical components (