Voltage and power quality improvement strategy for a DFIG wind turbine during variable wind conditions

This paper presents a voltage and power quality enhancement scheme for a doubly-fed induction generator (DFIG) wind farm during variable wind conditions. The wind profiles were derived considering the measured data at a DFIG wind farm located in Northern Ireland (NI). The aggregated DFIG wind farm model was validated using measured data at a wind farm during variable generation. The voltage control strategy was developed considering the X/R ratio of the wind farm feeder which connects the wind farm and the grid. The performance of the proposed strategy was evaluated for different X/R ratios, and wind profiles with different characteristics. The impact of flicker propagation along the wind farm feeder and effectiveness of the proposed strategy is also evaluated with consumer loads connected to the wind farm feeder. It is shown that voltage variability and short-term flicker severity is significantly reduced following implementation of the novel strategy described.

Food web indicators under the Marine Strategy Framework Directive: From complexity to simplicity?

The Marine Strategy Framework Directive (MSFD) requires that European Union Member States achieve "Good Environmental Status" (GES) in respect of 11 Descriptors of the marine environment by 2020. Of those, Descriptor 4, which focuses on marine food webs, is perhaps the most challenging to implement since the identification of simple indicators able to assess the health of highly dynamic and complex interactions is difficult. Here, we present the proposed food web criteria/indicators and analyse their theoretical background and applicability in order to highlight both the current knowledge gaps and the difficulties associated with the assessment of GES. We conclude that the existing suite of indicators gives variable focus to the three important food web properties: structure, functioning and dynamics, and more emphasis should be given to the latter two and the general principles that relate these three properties. The development of food web indicators should be directed towards more integrative and process-based indicators with an emphasis on their responsiveness to multiple anthropogenic pressures. (C) 2013 Elsevier Ltd. All rights reserved.

Using mixed-methods to examine teachers’ attitudes to educational change:The case of the Skills for Life strategy for improving adult literacy and numeracy skills in England.

This paper reports on a longitudinal study that examines how a national reform introduced in England in the field of adult literacy, language, and numeracy is affecting teachers. The paper focuses on the use of a mixed methodology to explore teachers' attitudes to the reform and how these change over time. The quantitative strand includes the construction and use of a Likert-type instrument for measuring the attitudes of a panel of 1,500 teachers. The qualitative strand builds on the quantitative results and includes focus groups and in-depth interviews with a subsample of teachers in the panel. As the study is still in its initial phase, the purpose is not to present findings, but to discuss how quantitative and qualitative evidence can be combined in evaluation research.

Performance management systems and Public Value Strategy: a case study

Purpose
This article aims to analyze the role of performance management systems (PMS) in supporting public value strategies.

Design/methodology/approach
This article draws on the public value dynamic model by Horner and Hutton (2010). It presents the results of a case study of implementation of a PMS model, the ‘Value Pyramid’ (VP).

Findings
The results stress the need for an improved conceptualization of PMS within public value strategy. Through experimentation using the VP, the case site was able to measure and visualize what it considered public value and reflect on the internal/external causes of both creation and destruction of public value.

Research limitations/implication
This article is limited to just one case study, although in-depth and longitudinal.

Originality/value
This article is one of the first attempting to understand the role of PMS within the public value strategy framework, answering the call of Benington and Moore (2010) to consider public value from an accounting perspective.

Adaption and adjustment of military spouses to overseas postings: An online forum study

Little research has examined the impact of being an accompanying spouse on British military foreign postings. The aim of this qualitative study was to investigate the experiences of 13 military spouses from 11 different overseas locations. Data were collected via an online forum and thematic content analysis was conducted. Key findings revealed that, regardless of the location, reactions to overseas posting varied considerably and were related to the military spouse's personality and personal circumstances, as well as their relationship with family, husband and their support networks. Spouses experienced a loss of control over their lives that was in some cases psychologically distressing. The findings corroborate and extend the findings from a previous study that was limited to one location, further highlighting the need for pre-established support resources from the military and healthcare professionals to be readily accessible for all military spouses. Importantly, such support provision may also facilitate the military spouse in regaining some control over their everyday life, enhancing their well-being and the experience for the family.

The impact of foreign postings on accompanying military spouses: an ethnographic study

As part of an ethnographic study, the impact of foreign postings on spouses who accompany military personnel was explored. Individual interviews and focus groups with 34 British military spouses based in one location in southern Europe were conducted. Key findings suggested that reaction to a foreign posting was a reflection of personal attitudes, prior experiences, support, ability to adjust to change and strength of relationship with the serving spouse and community. For many the experience was positive due to the increased opportunity for family time, for others this helped to compensate for the difficulties experienced. Some military spouses experienced significant distress on the posting, particularly if the family was not well-supported. The potential implications of military spouses not adapting to foreign postings have significant implications for healthcare practice. Provision of more appropriate support resources before and during the posting would facilitate the transition for the military spouse and their family.