Transformer Oil Passivation and Impact of Corrosive Sulphur

In recent years a significant volume of research has been undertaken in order to understand the recent failures in oil insulated power apparatus due to deposition of copper sulphide on the conductors and in the insulation paper. Dibenzyl Disulfide (DBDS) has been found to be the leading corrosive sulphur compound in the insulation oil [1]. The process of copper sulphide formation and the deposition in the paper is still being investigated, but a recently proposed method seems to be gaining some confidence [1]. This method suggests a two-step process; initially the DBDS and some oil soluble copper complexes are formed. Secondly the copper complexes are absorbed in the paper insulation, where they then decompose into copper sulphide [2]. The most commonly used mitigating technique for corrosive sulphur contaminated oil is passivation, normally using Irgamet 39 or 1, 2, 3-benzotriazole (BTA). The passivator is diluted into the oil to a concentration of around 100ppm, where it then reacts with the copper conductors to form a complex layer around the copper, preventing it from interacting with DBDS compounds and forming copper sulphide. This research project will investigate the electrical properties of HV transformers which have tested positive for corrosive sulphur, and the evolution of those properties as the asset degrades due to sulphur corrosion. Parallel to this the long term properties of transformers with passivated insulation oil will be analysed in order to understand the passivator stability and whether it is necessary to keep adding the passivator to sustain its performance. Condition monitoring techniques under investigation will include dielectric spectroscopy, frequency response analysis, recovery voltage method (aka interfacial polarisation) amongst others. Partial discharge techniques will not be investigated, as the voltage between the coil plates is low and therefore it will not contribute significantly to the overall insulation breakdown, in corrosive oil related faults [3]. The goal of this research is to establish key electrical properties in both passivated and non-passivated power transformers that demonstrate detectable changes as the equipment degrades due to the insulation oil being corrosive

Presenting Computer Science Concepts to High School Students

Computer science at high school often focusses on programming, but a broader view of other areas of computer science has key benefits for both writing programs that are more efficient and making more theoretical concepts more accessible to those who do not find programming intrinsically interesting. With the introduction of computer science at high schools, a lack of coherent resources for teachers and students prompted the development of the NZ Computer Science Field Guide, an open-source, on-line textbook. This paper describes the design of the Field Guide, which has fourteen chapters about various topics of computer science. The design includes written text, videos, classroom activities and interactive applications. The need for a broad view of computer science is discussed, and programming exercises to go with the topics are suggested

Adoption of Computer Science in NZ schools

In 2011, Programming and Computer Science standards were made available as part of NCEA in New Zealand high schools. Because little guidance and professional development was available initially, teachers have found it challenging to present the content effectively to their students. In response to this, several resources and professional development opportunities have been made available, including the widely used Computer Science Field Guide for Computer Science, and several programming resources specific to the new standards. In this paper we outline the deployment of the new standards and supporting material, and look at the uptake of the new standards over the first three years that they were phased in. This reveals increasing participation at schools, and higher enrolments at university as a flow-on effect. The introduction of Computer Science has also helped to address perception and stereotypes about the industry, with high achievement by female students, although participation rates are not ideal

Black dyes for coir fibre: 3 practical considerations

Earlier trials on Synacril Black A, Benzamin Black DS 167% and Suprexcel Black VY- three possible substitute dyes for Chlorazol Black E -showed the effect of variations in dyebath conditions on the amount of dye deposited on coir (Canning, A. J., Jarman, C. G. and Mykoluk, S. M. (1979) Black dyes for coir fibre. Part 2. Evaluation of selected dyes. Report of the Tropical Products Institute, L52). Further trials, in which both different concentrations of dye in the bath, and a standing bath were used, have now been carried out to obtain additional data on the exhaustion characteristics of the three dyes. Additionally, the effect of variations in dyebath conditions on the quality of colour, and the amount of each of the three dyes that needs to be deposited on to the fibre to produce an acceptable black, have been assessed. With all three dyes, dyebath exhaustion was approached more slowly with increased dyebath concentration. As a consequence, when additional dye is used, dyeing time must be increased to obtain the most efficient use of dye. Since the proportion of dye that exhausts from the bath is also reduced, particularly with the higher dyebath concentrations or the shorter dyeing times, increasingly large additions of dye are required in order to intensify the visual depth of shade. With low dyebath concentrations of the two direct dyes (Benzamin Black and Suprexcel Black), allowing the liquor to cool during dyeing could reduce heating costs since the exhaustion obtained after 1.5 hours at 95°C followed by cooling was similar to that obtained after 6 hours at 95°C. However, with deeper shades the opportunity for reducing heating costs by reducing dyeing time at 95°C and then cooling is less. The inclusion of sodium carbonate in the dyebath could also result in savings on dyestuff. When using a standing bath technique with Benzamin Black, significantly different exhaustion/time relationships were obtained with each batch of fibre. As a consequence there would be considerable practical difficulties in using this dye with this technique. On the other hand, the exhaustion of Suprexcel Black was only slightly affected by the use of replenished liquors and a standing bath technique could reduce costs. Because of its almost complete exhaustion, there would be no advantage in using a standing bath with the basic dye Synacril Black. All the dyes gave better light-fastness properties when they were concentrated at the periphery of the fibre rather than when they penetrated more deeply: however, staining of adjacent fabrics was greater. The distribution of the dye within the fibre did not affect the visual colour. All three dyes should produce black colours which are technically similar to those of commercial samples of black coir. The amounts which need to be deposited on the fibre to produce an acceptable black are estimated as approximately: Benzamin Black DS 167% - 19g per kilogram of fibre; Suprexcel Black VY - 22g per kilogram of fibre; Synacril Black A - 10g per kilogram of fibre. Fastness properties of the blacks vary with the dye and the technique used to apply it. Information on the development of optimum dyeing conditions is appended

Developing a decision support tool for the positioning and sizing of vortex flow controls in existing sewer systems

12th International Conference on Computing and Control for the Water Industry, CCWI2013This is the final version of the article. Available from Elsevier via the DOI in this record.This paper describes the development of a decision support tool for the positioning and sizing of vortex flow controls in existing sewer systems. The tool aims to prioritise the placement of vortex flow controls primarily within subcatchments with the greatest flood consequence rating and maximise the use of unused inpipe volumes during critical rainfall events. The decision support tool is intended for use in catchments where opportunities to implement SuDS and rainwater harvesting to defend against flooding are limited. The decision support tool is envisaged to identify potential strategies which could enhance flood resistance of sewer systems in a cost effective manner. © 2013 The Authors

Prevalence and experiences of food insecurity among immigrant women connected to perinatal programs at a community-based organization in Edmonton, Canada

Purpose: The purpose of this paper is to investigate the prevalence of household food insecurity among immigrant women connected to perinatal programs offered through a community-based organization in Edmonton, and to explore their experiences in coping with food insecurity. Design/methodology/approach: This study utilized a mixed methods research design. A community-based participatory research approach was used to engage health workers who were connected to immigrant women and families through the Multicultural Health Brokers Cooperative in Edmonton. Through the health workers a sample of 213 immigrant women connected to their perinatal programs completed the Household Food Security Survey. Following the survey, 17 women completed semi-structured interviews which were analyzed using content analysis. Findings: The vast majority of women (94 percent (n=199)) lived in food insecure households, and 53 percent (n=112) in severely food insecure. In semi-structured interviews, women specifically described not having enough money to buy vegetables, fruit and meat, and perceiving a lack of control over foods they ate and offered to their families. Practical implications: This study highlights the need for support to be provided to immigrant families for acquiring healthy food in Canada. Originality/value: The mixed methods design with a decent sample of often underrepresented research participants highlights an area in need of further research and greater support

ENVIROSAT-2000 report: Federal agency satellite requirements

The requirement of Federal agencies, other than NOAA, for the data and services of civil operational environmental satellites (both polar orbiting and geostationary) are summarized. Agency plans for taking advantage of proposed future Earth sensing space systems, domestic and foreign, are cited also. Current data uses and future requirements are addressed as identified by each agency

Making progress? What progression means for people serving the longest sentences

This report presents the findings of a prisoner consultation carried out by PRT’s Building Futures programme. Around 100 responses were received from people in prison to four questions relating to their progression. The report looks at what is meant by risk reduction and assessment, and progression both in terms of offending behaviour courses and the personal progression of prisoners. It also examines the relationship between risk and progression, and the lack of clarity felt by prisoners. The report identifies missed oportunities for the progression and development of long-term prisoners but makes recommendations to improve the system

Current Models of Investor State Dispute Settlement Are Bad for Health: The European Union Could Offer an Alternative Comment on "The Trans-Pacific Partnership: Is It Everything We Feared for Health?"

In this commentary, we endorse concerns about the health impact of the trans-pacific partnership (TPP), paying particular attention to its mechanisms for investor state dispute settlement. We then describe the different, judge-led approach being advocated by the European Commission team negotiating the Trans-Atlantic Trade and Investment Partnership, arguing that, while not perfect, it offers significant advantages