Development of a switch mode assisted linear amplifier for use as a high fidelity voltage source

Frequency Domain Spectroscopy (FDS) is one of the major techniques used for determining the condition of the cellulose based paper and pressboard components in large oil/paper insulated power transformers. This technique typically makes use of a sinusoidal voltage source swept from 0.1 mHz to 1 kHz. The excitation test voltage source used must meet certain characteristics, such as high output voltage, high fidelity, low noise and low harmonic content. The amplifier used; in the test voltage source; must be able to drive highly capacitive loads. This paper proposes that a switch-mode assisted linear amplifier (SMALA) can be used in the test voltage source to meet these criteria. A three level SMALA prototype amplifier was built to experimentally demonstrate the effectiveness of this proposal. The developed SMALA prototype shows no discernable harmonic distortion in the output voltage waveform, or the need for output filters, and is therefore seen as a preferable option to pulse width modulated digital amplifiers. The lack of harmonic distortion and high frequency switching noise in the output voltage of this SMALA prototype demonstrates its feasibility for applications in FDS, particularly on highly capacitive test objects such as transformer insulation systems.

Real time maximum power conversion tracking and resonant frequency modification for high power piezoelectric ultrasound transducer

Piezoelectric ultrasound transducers are commonly used to convert mechanical energy to electrical energy and vice versa. The transducer performance is highly affected by the frequency at which it is excited. If excitation frequency and main resonant frequency match, transducers can deliver maximum power. However, the problem is that main resonant frequency changes in real time operation resulting in low power conversion. To achieve the maximum possible power conversion, the transducer should be excited at its resonant frequency estimated in real time. This paper proposes a method to first estimate the resonant frequency of the transducer and then tunes the excitation frequency accordingly in real time. The measurement showed a significant difference between the offline and real time resonant frequencies. Also, it was shown that the maximum power was achieved at the resonant frequency estimated in real time compare to the one measured offline.

Modelling of Electric Fields

South Africa has an electrical transmission grid of over 25 000 km of overhead power lines with voltages of 132 kV to 765 kV. The grid has been largely designed and built by the power utility, Eskom. This book embodies the planning philosophies, design principles and construction practices of Eskom. It is the culmination of decades of thought, study, research and the practical experience of many overhead power line engineers and researchers. The book covers the main aspects of overhead power line design and construction, from electrical first principles, system planning, insulation co-ordination (including live line working), mechanical design through to environmental impact management and power line communications. The content emphasises the need for close interaction between all technical disciplines involved and the importance of optimising designs for economy and performance. Additional challenges in South Africa are the relatively high altitude of the interior plateau (1 000 m to 1 700 m above sea level), severe lightning in some areas and long transmission distances. The book explains how these factors are accommodated in modern designs. Other advanced work covered includes the use and understanding of polymeric insulators, the judicious reduction of phase-to-phase spacings and the adoption of guyed structures.

Australian Consumer Law Commentary and Materials [5th Ed.]

"The Australian Consumer Law came into operation on 1 January 2011 as a single national law. It replaced 17 different pieces of Commonwealth, State and Territory legislation relating to consumer protection. Its introduction meant that for the first time, consumers throughout Australia had the same rights and remedies and correspondingly, businesses had the same obligations and responsibilities towards consumers without the barrier of confusing and expensive local variations in the law. Australian Consumer Law: Commentary and Materials contains up-to-date material on the Australian Consumer Law, and in particular the fifth edition incorporates: a revised treatment of unconscionability, taking account of the changes to Part 2-2 of the ACL that became effective in 2012; other State and Federal provisions relating to unfair terms and cases such as Kakavas v Crown Melbourne, ACCC v Lux Distributors, Director of Consumer Affairs v Scully and PT Ltd v Spuds Surf; a comprehensive treatment of the impact of Google v ACCC, Forrest v ASIC and ACCC v TPG – the trilogy of decisions that provide the most recent insights into the High Court’s thinking on aspects of the prohibitions of misleading conduct in the ACL and the Corporations Act 2001; numerous decisions of note; and the possible impact of the Harper Review."--publisher website

Feedback on student performance in the workplace: The role of workplace supervisors

This chapter highlights the im portance of feedback in work - integrated learning (WIL) , the key role of workplace supervisors, and the importance of continuous improvement in systems to support feedback processes. The paper proposes a definition of feedback and formative feedback, as well as approaches for providing industry feedback in W I L . It further reports on a case analysis based on workplace supervisors providing feedback to students in engineering and urban development , yielding certain insights into student pe rformance in the workplace, and m ore importantly, hi ghlighting the need to enhance the use of feedback processes. This is requir ed in a context where delivering feedback in WIL is generally acknowledge d to be complex, and where the role of the industry supervisor in appraising the performance of the student in the workplace needs to be very c learly defined in order for supervisor s ’ feedback to have optimal impact. F eedback in WIL i s set against the bac kdrop of recognizing the importance and complexity of stakeholder engagement in WIL in general, and the intricacy associated with the provision of feedback from industry supervisors in particular. Student self - assessment is briefly considered as a fu rther dimension of their participation in providing feedback on their own performance in the workplace . ( Asia - Pacific Journal of Cooperative Education, Special Issue, 2014, 15 (3 ), 241 - 25 2

Altered nociceptive, endocrine, and dorsal horn neuron responses in rats following a neonatal immune challenge

Summary The neonatal period is characterized by significant plasticity where the immune, endocrine, and nociceptive systems undergo fine-tuning and maturation. Painful experiences during this period can result in long-term alterations in the neurocircuitry underlying nociception, including increased sensitivity to mechanical or thermal stimuli. Less is known about the impact of neonatal exposure to mild inflammatory stimuli, such as lipopolysaccharide (LPS), on subsequent inflammatory pain responses. Here we examine the impact of neonatal LPS exposure on inflammatory pain sensitivity and HPA axis activity during the first three postnatal weeks. Wistar rats were injected with LPS (0.05 mg/kg IP, Salmonella enteritidis) or saline on postnatal days (PNDs) 3 and 5 and later subjected to the formalin test at PNDs 7, 13, and 22. One hour after formalin injection, blood was collected to assess corticosterone responses. Transverse spinal cord slices were also prepared for whole-cell patch clamp recording from lumbar superficial dorsal horn neurons (SDH). Brains were obtained at PND 22 and the hypothalamus was isolated to measure glucocorticoid (GR) and mineralocorticoid receptor (MR) transcript expression using qRT-PCR. Behavioural analyses indicate that at PND 7, no significant differences were observed between saline- or LPS-challenged rats. At PND 13, LPS-challenged rats exhibited enhanced licking (p < .01), and at PND 22, increased flinching in response to formalin injection (p < .05). LPS-challenged rats also displayed increased plasma corticosterone at PND 7 and PND 22 (p < .001) but not at PND 13 following formalin administration. Furthermore, at PND 22 neonatal LPS exposure induced decreased levels of GR mRNA and increased levels of MR mRNA in the hypothalamus. The intrinsic properties of SDH neurons were similar at PND 7 and PND 13. However, at PND 22, ipsilateral SDH neurons in LPS-challenged rats had a lower input resistance compared to their saline-challenged counterparts (p < .05). These data suggest neonatal LPS exposure produces developmentally regulated changes in formalin-induced behavioural responses, corticosterone levels, and dorsal horn neuron properties following noxious stimulation later in life. These findings highlight the importance of immune activation during the neonatal period in shaping pain sensitivity later in life. This programming involves both spinal cord neurons and the HPA axis.

Founder p.Arg 446* mutation in the PDHX gene explains over half of cases with congenital lactic acidosis in Roma children

Investigation of 31 of Roma patients with congenital lactic acidosis (CLA) from Bulgaria identified homozygosity for the R446* mutation in the PDHX gene as the most common cause of the disorder in this ethnic group. It accounted for around 60% of patients in the study and over 25% of all CLA cases referred to the National Genetic Laboratory in Bulgaria. The detection of a homozygous patient from Hungary and carriers among population controls from Romania and Slovakia suggests a wide spread of the mutation in the European Roma population. The clinical phenotype of the twenty R446* homozygotes was relatively homogeneous, with lactic acidosis crisis in the first days or months of life as the most common initial presentation (15/20 patients) and delayed psychomotor development and/or seizures in infancy as the leading manifestations in a smaller group (5/20 patients). The subsequent clinical picture was dominated by impaired physical growth and a very consistent pattern of static cerebral palsy-like encephalopathy with spasticity and severe to profound mental retardation seen in over 80% of cases. Most patients had a positive family history. We propose testing for the R446* mutation in PDHX as a rapid first screening in Roma infants with metabolic acidosis. It will facilitate and accelerate diagnosis in a large proportion of cases, allow early rehabilitation to alleviate the chronic clinical course, and prevent further affected births in high-risk families.

Tissue engineered humanized bone supports human hematopoiesis in vivo

Advances in tissue-engineering have resulted in a versatile tool-box to specifically design a tailored microenvironment for hematopoietic stem cells (HSCs) in order to study diseases that develop within this setting. However, most current in vivo models fail to recapitulate the biological processes seen in humans. Here we describe a highly reproducible method to engineer humanized bone constructs that are able to recapitulate the morphological features and biological functions of the HSC niches. Ectopic implantation of biodegradable composite scaffolds cultured for 4 weeks with human mesenchymal progenitor cells and loaded with rhBMP-7 resulted in the development of a chimeric bone organ including a large number of human mesenchymal cells which were shown to be metabolically active and capable of establishing a humanized microenvironment supportive of the homing and maintenance of human HSCs. A syngeneic mouse-to-mouse transplantation assay was used to prove the functionality of the tissue-engineered ossicles. We predict that the ability to tissue engineer a morphologically intact and functional large-volume bone organ with a humanized bone marrow compartment will help to further elucidate physiological or pathological interactions between human HSCs and their native niches.

Convergence of regenerative medicine and synthetic biology to develop standardized and validated models of human diseases with clinical relevance

In order to progress beyond currently available medical devices and implants, the concept of tissue engineering has moved into the centre of biomedical research worldwide. The aim of this approach is not to replace damaged tissue with an implant or device but rather to prompt the patient's own tissue to enact a regenerative response by using a tissue-engineered construct to assemble new functional and healthy tissue. More recently, it has been suggested that the combination of Synthetic Biology and translational tissue-engineering techniques could enhance the field of personalized medicine, not only from a regenerative medicine perspective, but also to provide frontier technologies for building and transforming the research landscape in the field of in vitro and in vivo disease models.

X-ray Structure of Gelonin at 1.8 Å Resolution

Gelonin is a single chain ribosome inactivating protein (RIP) with potential application in the treatment of cancer and AIDS. Diffraction quality crystals grown using PEG3350, belong to the space group P2(1), with it a = 49.4 Angstrom b = 44.9 Angstrom, c = 137.4 Angstrom and beta = 98.4 degrees, and contain two molecules in the asymmetric unit. Diffraction data collected to 1.8 Angstrom resolution has a R(m) value of 7.3%. Structure of gelonin has been solved by the molecular replacement method, using ricin A chain as the search model. Crystallographic refinement using X-PLOR resulted in a model for which the r.m.s deviations from ideal bond lengths and bond angles are 0.012 Angstrom and 2.7 degrees, respectively The final R-factor is 18.4% for 39,806 reflections for which I > 1.0 sigma(I).The C-alpha atoms of the two molecules in the asymmetric unit superpose to within 0.38 Angstrom for 247 atom pairs. The overall fold of gelonin is similar to that of other RIPs such as ricin A chain and alpha-momorcharin, the r.m.s.d. for C-alpha superpositions being 1.3 and 1.4 Angstrom, respectively The-catalytic residues (Glu166, Arg169 and Tyr113) in the active site form a hydrogen bond scheme similar to that observed in other RIPs. The conformation of Tyr74 in the active site, however, is significantly different from that in alpha-momorcharin. Three well defined water molecules are located in the active site cavity and one of them, X319, superposes to within 0.2 Angstrom of a corresponding water molecule in the structure of alpha-momorcharin. Any of the three could be the substrate water molecule in the hydrolysis reaction catalysed by gelonin.Difference electron density for a N-linked sugar moiety has been observed near only one of the two potential glycosylation sites in the sequence. The amino acid at position 239 has been established as Lys by calculation of omit electron density maps.The two cysteine residues in the sequence, Cys44 and Cys50, form a disulphide bond, and are therefore not available for disulphide conjugation with antibodies. Based on the structure, the region of the molecule that is involved in intradimer interactions is suggested to be suitable for introducing a Cys residue for purposes of conjugation with an antibody to produce useful immunotoxins.

Association of NOS1AP variants and depression phenotypes in schizophrenia

Background The nitric oxide synthase 1 adaptor protein gene (NOS1AP) has previously been recognised as a schizophrenia susceptibility gene due to its role in glutamate neurotransmission. The gene is believed to inhibit nitric oxide (NO) production activated by the N-methyl-d-aspartate (NMDA) receptor and reduced NO levels have been observed in schizophrenia patients. However, association studies investigating NOS1AP and schizophrenia have produced inconsistent results, most likely because schizophrenia is a clinically heterogeneous disorder. This study aims to investigate the association between NOS1AP variants and defined depression phenotypes of schizophrenia. Methods Nine NOS1AP SNPs, rs1415259, rs1415263, rs1858232, rs386231, rs4531275, rs4656355, rs4657178, rs6683968 and rs6704393 were genotyped in 235 schizophrenia subjects screened for various phenotypes of depression. Result One NOS1AP SNP (rs1858232) was associated with the broad diagnosis of schizophrenia and eight SNPs were associated with depression related phenotypes within schizophrenia. The rs1415259 SNP showed strong association with sleep dysregulation phenotypes of depression. Conclusion Results suggest that NOS1AP variants are associated with various forms of depression in schizophrenia and are more prevalent in males. Limitation Schizophrenia is a clinically heterogeneous disease that can vary greatly between different ethnic and geographic populations so our observations should be viewed with caution until they are independently replicated, particularly in larger patient cohorts.

Rapid assessment of genotype-by-environment interactions and heritability for growth rate in aquaculture species using in vitro fertilisation and DNA tagging

Commercial environments may receive only a fraction of expected genetic gains for growth rate as predicted from the selection environment This fraction is the result of undesirable genotype-by-environment interactions (G x E) and measured by the genetic correlation (r(g)) of growth between environments. Rapid estimates of genetic correlation achieved in one generation are notoriously difficult to estimate with precision. A new design is proposed where genetic correlations can be estimated by utilising artificial mating from cryopreserved semen and unfertilised eggs stripped from a single female. We compare a traditional phenotype analysis of growth to a threshold model where only the largest fish are genotyped for sire identification. The threshold model was robust to differences in family mortality differing up to 30%. The design is unique as it negates potential re-ranking of families caused by an interaction between common maternal environmental effects and growing environment. The design is suitable for rapid assessment of G x E over one generation with a true 0.70 genetic correlation yielding standard errors as low as 0.07. Different design scenarios were tested for bias and accuracy with a range of heritability values, number of half-sib families created, number of progeny within each full-sib family, number of fish genotyped, number of fish stocked, differing family survival rates and at various simulated genetic correlation levels

Rank regression for analyzing ordinal qualitative data for treatment comparison

Ordinal qualitative data are often collected for phenotypical measurements in plant pathology and other biological sciences. Statistical methods, such as t tests or analysis of variance, are usually used to analyze ordinal data when comparing two groups or multiple groups. However, the underlying assumptions such as normality and homogeneous variances are often violated for qualitative data. To this end, we investigated an alternative methodology, rank regression, for analyzing the ordinal data. The rank-based methods are essentially based on pairwise comparisons and, therefore, can deal with qualitative data naturally. They require neither normality assumption nor data transformation. Apart from robustness against outliers and high efficiency, the rank regression can also incorporate covariate effects in the same way as the ordinary regression. By reanalyzing a data set from a wheat Fusarium crown rot study, we illustrated the use of the rank regression methodology and demonstrated that the rank regression models appear to be more appropriate and sensible for analyzing nonnormal data and data with outliers.

Preliminary phonological analysis of the Limi dialect of Humla Bhotia

The purpose of this research was to analyse the phonological system of the Limi dialect of Humla Bhotia. Humla Bhotia is a Tibeto-Burman language that is spoken by approximately 4000 5000 people in the far northwestern Humla province of the Kingdom of Nepal. The language has not previously been the subject of analysis. The data base for this thesis was collected on two different dialects of Humla Bhotia in Kathmandu, the capital of Nepal, from February to May 2000. I had three language informants who speak Humla Bhotia as their mother tongue. One of the informants speaks the Upper Humla dialect and the other two informants speak the Limi dialect. In this thesis I have concentrated on the phonology of the dialect of Limi but occasionally I also make reference to the Upper Humla dialect. The Limi data base consists of 600 words elicited in isolation, sentences where words have been checked for consonantal and pitch variation, and five texts comprising 117 sentences. Firstly, I have studied the geographical location, population and dialects of Humla Bhotia. Five dialects were identified: Limi, Upper Humla, La Yakba, Nyinba and Humli Khyampa. Information on the dialect areas is based on the accounts of seven mother tongue speakers of the language and on Nancy Levine s (1988) anthropological research of the ethnic group Nyinba. Secondly, I have analysed the phonological system of Limi from the viewpoint of American stucturalism much along the lines followed by Pike 1966 [1947] ja 1967 [1948]. In defining the prosodic elements I have also used acoustic analysis. In the Limi dialect there are 7 vowel phonemes. No vowel clusters occur within the same syllable. In this preliminary analysis 29 contrastive plosives, 8 affricates and 5 6 fricatives were found. The data also revealed 4 nasal phonemes, two rhotic phonemes, one lateral phoneme and two central approximants. Further research is however called for to check the phonemic status of these segments. Four contrastive prosodic elements were encountered: nasalisation, length, phonation type and pitch movement. There are two contrastive types of phonation: tense and lax. Many words were found with a third type of phonation, modal phonation. How modal phonation relates to the prosodic system is unclear at this stage and is therefore left for further research to determine. There are two contrastive pitch movement tonemes: a rising toneme and falling toneme. The falling toneme occurs in free variation with a level pitch contour. Rising appears to be linked with lax phonation and falling with tense phonation.

Metsäpirulainen : Liikemies Erik Johan Längman (1799-1863) talousjärjestelmän murroksessa

The Forest devil. Businessman Erik Johan Längman (1799 1863) in the transition of economic system In Finnish historiography, Erik Johan Längman (1799-1863) bears a bad reputation of his own level: a mean, profit-seeking businessman who did not care too much about methods in his operations. Although little known, Längman has been praised as one of the pioneers of modern industry in the Grand Duchy of Finland, which belonged to the Russian Empire. From the mid 1830s Längman owned iron mill and several sawmills around the country. The growing demand of the markets in the 1830s, especially in Great Britain, marked a strong stimulus to Finnish lumber industry. At the same time claims for stricter rule over the sawmill industry were raised by high officials. The momentum of the conflict, the Forest Act of 1851, brought an end to illegal overproduction. In this biography, particular emphasis is laid on the entrepreneurial behaviour of Längman, but also on the effect the entrepreneurs had on the Crown s policies. On the other hand, how did the limitations imposed by the Crown guide the actions of the sawmill owners? The solutions adopted by the sawmill owners and the manoeuvring of the government are in a constant dialogue in this study. The Finnish sawmill industry experienced a major change in its techniques and methods of acquiring timber during the 1830s. Längman particularly, with his acquisition organisation, was able to find and reach faraway forests with unexpected results. The official regulating system with its strict producing quotas couldn t follow the changes. When the battle against the sawmill industry really started on, in 1840, it didn t happen for the benefit of iron industry, as argued previously, but to save Crown forests from depletion. After the mid 1840s Längman and the leader of the Finnish nationalistic movement, J. V. Snellman questioned the rationality of the entire regulation system and in doing so they also posed a threat against the aristocratic power. The influential but now also badly provoked chairman of the economic division of senate, Lars Gabriel von Haartman, accused the sawmill-owners harder than ever and took the advantage of the reactionary spirit of imperial Russia to launch the state forest administration. Längman circumvented the conditions of privileges, felled Crown forests illegally and accusations were brought against him for destroying his competitors. The repeated conflicts spoke primarily about a superior business idea and organisational ability. Although Längman spent his last years mostly abroad he still had interests in Finnish timber business when the liberation of sawmill-industry was established, in 1861. Surprisingly, the antagonism around the Crown forests continued, probably even more heated.