1. Despite extensive research on oral squamous cell carcinoma (OSCC), its five-year survival rate has not improved for the last two decades. Effective treatment of OSCC requires the identification of molecular targets to design appropriate therapeutic strategies. To this end, DDRT-PCR analysis was used to identify molecular markers, which could be used as therapeutic targets. 2. DDRT-PCR in combination with reverse Northern analysis identified 25 differentially expressed genes in oral tumors. Fourteen genes did not show homology to any known gene in the database and therefore may represent non-specific genomic DNA sequences or novel genes that have not yet been identified. The remaining 11 genes showed homology to known genes such as DIAPH1, NJMU-R1, RBM28, PCNA, GLTP, MTATP6, ZKSCAN1, TNKS2, PAM, TUBB2C and C14orf154. TNKS2, PAM, TUBB2C and C14orf154 showed downregulation and the remaining seven genes were upregulated in oral tumor samples. 3. To reconfirm the results of DDRT-PCR and reverse Northern blot analyses, Northern blot analysis was carried out on matched normal and tumor samples for a few genes. As expected, PCNA, NJMU-R1 and ZKSCAN1 showed upregulation, whereas TUBB2C showed downregulation in the tumor sample. PCNA was also found to be upregulated in tumor samples at the protein level. 4. The expression of eight differentially expressed genes (viz., DIAPH1, NJMU-R1, RBM28, PCNA, GLTP, TNKS2, PAM and TUBB2C) was also validated in a panel of 16 matched normal and tumor samples. The mean mRNA expression levels of GLTP, PCNA, RBM28, NJMU-R1 and DIAPH1 were significantly greater in tumor samples than in normal samples. The mean expression levels of TNKS2, PAM and TUBB2C were significantly lower in tumor samples than in normal samples. 5. As some of the genes like NJMU-R1, RBM28, GLTP and PAM are found to differentially regulated in a majority of the tumors, they could be used as potential markers in oral cancer. 6. Tuberin and hamartin have been placed as a complex in the insulin signaling pathway and are known to negatively regulate this pathway. Since overexpression of TSC2 has been previously shown to exert antitumor effect on two oral cancer cell lines, and some components of the insulin signaling pathway have already been implicated in head and neck cancers, we reasoned that both TSC genes and other key players of this pathway might be differentially regulated in oral tumors. Northern blot analysis showed downregulation of the TSC2 gene in an oral tumor sample. In order to further validate the expression pattern of the TSC2 gene, a semiquantative RT-PCR analysis was carried out in a panel of 16 matched normal and tumor samples. The mean expression level of TSC2 was significantly lower in tumor samples than in normal tissue samples. The mean expression level of its interacting partner TSC1 was also significantly lower in tumor samples than in normal tissue samples, suggesting the involvement of these genes in the etiology of oral cancer. TSC1 and TSC2 were also downregulated in eight matched normal and tumor samples at the protein level. We wanted further to determine the expression of both TSC genes in cell lines. Interestingly, TSC2 did not show a detectable level of expression in an oral cancer cell line SCC 131, whereas it was expressed in two other oral cancer cell lines KB and SCC 104 as well as in four non-oral cell lines: A549, HEK-293T, HeLa and HepG2 at the protein level. The TSC2 expression in KB was, however, lower than in other cell lines. TSC1 was expressed in all the cell lines, albeit at different levels. The TSC1 expression was lower in SCC 131 as compared to two other cell lines KB and SCC 104. 7. Given the fact that both are tumor suppressors, it was hypothesized that LOH, inactivating somatic mutations and/or promoter methylation might be playing a role for their downregulation in oral tumors. Mutation analysis of all the coding regions of both the TSC genes failed to detect any mutation in a panel of 25 tumor samples. However, seven normal population variants were identified in different patients. Our analysis of the matched peripheral blood and tumor DNA samples from 52 patients showed LOH at both the TSC loci. At the TSC1 locus, 17/48 (35.42%) tumors showed an allelic loss for one or more markers. At the TSC2 locus, LOH was found in 18/48 (37.5%) informative cases. Nine patients (9/48, 18.75%) had LOH at both the TSC loci. Since PTEN is another tumor suppressor in the insulin signaling pathway, we then sought to determine if LOH is also present in the PTEN candidate region in a panel of 50 matched samples. Microsatellite analysis using three markers showed a low LOH rate of 13% in tumor samples. 8. As the OSCC cell line SCC 131 did not show a detectable level of TSC2 expression, we treated this cell line with methylation inhibition drug 5-azacytidine. The treatment restored the expression of TSC2 and increased the expression of TSC1, suggesting that the promoter methylation and LOH are the important mechanisms for their downregulation. In order to see if the downregulation of the TSC genes is due to their promoters being methylated in tumors from the patients, we examined the methylation status of their promoters in 16 oral tumors, three normal oral tissues, two peripheral blood DNA samples from normal individuals and two cell lines HeLa and SCC 131 by COBRA. Our repeated efforts to amplify the TSC1 promoter using different DNA polymerases failed. However, we were able to successfully amplify the 571 bp long TSC2 promoter. Our analysis showed methylation of the TSC2 promoter in all tumors and two cell lines. As expected, the TSC2 promoter was not methylated in normal oral tissues and control blood DNA samples. Our bisulfite sequencing data suggested a low level and a considerable heterogeneity of methylation. 9. Using Fisher’s exact test, no correlation was found between LOH at the TSC loci and different clinical parameters such as age, sex, T classification, stage, grade, histology, tobacco habits and lymph node metastasis. 10. Using Fisher’s exact test, no correlation was found between the TSC2 promoter methylation and its downregulation in 16 tumor samples. We believe that this could be due to small sample size. 11. Since TSC1 and TSC2 are important regulators of the insulin pathway, it was hypothesized that other key players of this pathway might also be dysregulated in oral cancer. To this end, the expression pattern of some of the major regulators of the insulin pathway (viz., PI3K, AKT, PDK1, RHEB, mTOR, S6K1, S6, eIF4E, 4E-BP1, PTEN, 14-3-3ﾟ and IRS1) was investigated using semiquantative RT-PCR in a panel of 16 matched normal and tumor samples. The mean expression levels of the following genes showed significant upregulation in tumor samples: AKT, PI3K, PDK1, RHEB, mTOR, S6K1, S6 and eIF4E. On the other hand, 4E-BP1 and PTEN showed significant downregulation in tumor tissues. No significant difference in the expression was found for 14-3-3ﾟ and IRS1 between tumor and normal tissues. The expression pattern of some of these genes was also analyzed at the protein level using Western blot analysis and eight matched normal and tumor tissues. The level of total AKT was upregulated in 2/8 tumor samples only. However, phosphorylated-AKT (Thr308) showed upregulation in 6/8 samples. p70S6K1 and phosphorylated-p70S6K1 (Thr389) were upregulated in 8/8 and 6/8 tumor samples, respectively. Increase in the phosphorylated forms of both AKT and its downstream effector p70S6K1 suggested an increase in their kinase activity, indicating a constitutive activation of this pathway in oral cancer. 12. Based on our findings of mutation analysis, LOH study, 5-azacytidine treatment of an oral cancer cell line and COBRA analysis, we suggest that LOH at the TSC gene loci and promoter methylation are important mechanisms for the downregulation of the TSC genes. Loss of function of these genes may thus contribute to the constitutive activation of the insulin signaling pathway in oral cancer, leading to overall cell growth and proliferation. Our studies have shown that several key members of this pathway show aberrant expression in a subset of cancers of the oral cavity and can provide useful therapeutic targets. Several inhibitors of the insulin signaling pathway, such as rapamycin and its derivatives which inhibit mTOR and the PI3K inhibitor wortmannin, are now being actively evaluated for clinical trials for other cancers. We suggest that these inhibitors could also be evaluated for the treatment of oral cancer in future. Our differential display analysis has served to identify several genes that may be important for the onset and progression of oral cancer. Further analysis of these genes is warranted.

Eskom Holdings SOC Limited (referred to as Eskom), a public state owned company, is required to continually demonstrate environmental duty of care and report on its environmental performance. In furthering its commitment to sustainable development and in line with environmental compliance of its activities, Eskom is planning to have the Distribution Division certified against the International Organisation for Standardization (ISO) 14001:2004 environmental management system (EMS) standard by 2014. In general, management review may quickly turn into a dry review of the items on the agenda, done only to show an auditor the review was held. As such, the aim of this study was to assess the effectiveness of management reviews as one of the key continual improvement elements of the ISO 14001:2004 environmental management system within Eskom Distribution: Western Region. This research has been designed to take place in three stages. These stages are planning, execution and publication, and preparing the dissertation for marking. The research methodology included a literature study on various national and international articles and journals on EMSs that relate to environmental performance. The databases of Eskom Distribution: Western Region ‒ i.e. the management review presentation results for the 2008/09, 2009/10 and 2010/11 financial years, key significant environmental aspects for the Technical Service Centres (TSCs) and Minor/Major Engineering Works (MEW), key performance indicators (KPIs), Risk Audit System (RAS) results, and results of the external EMS audit conducted from 23–25 April 2007 were used for this research. Questionnaires were sent to the TSCs’ senior supervisors and Safety, Health, Environment and Quality (SHEQ) management. An analysis of the questionnaires completed by the TSC senior supervisors showed that all the participants have seen an improvement in environmental performance due to annual management reviews, except TSC11, who have not seen management review results. It can be concluded from the results of the SHEQ management questionnaires that an improvement (continual improvement as per the ISO 14001 requirement) was observed. The improvements were identified through improved processes, improved gap analysis, increased environmental awareness, and addressing risks. Most of the ISO 14001:2004 requirements for the management review for all financial years covered in this study were met. In terms of the objectives, targets and KPIs, Eskom Distribution: Western Region performed effectively and most of the outcomes were implemented according to the recommendations. Further, based on the external audit conducted from 23 to 25 April 2007, it is clear that Eskom Distribution: Western Region conformed to the minimum requirements of the ISO 14001:2004 EMS. Their management reviews also met all requirements of the ISO 14001:2004 relating to management review. This was proven by minutes of previous meetings that covered all the necessary issues that were audited. Thus, the existence of management reviews contributed towards ensuring that the ISO system was scrutinised and improved where it worked, and that aspects that did not work well were removed. / M. Environmental Management, North-West University, Potchefstroom Campus, 2014

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects several organs in the human body including the brain, heart, kidneys, eyes, skin, spleen, liver and lungs [Roach, et al., 1999]. TSC is characterized by hamartomas that rarely progress to malignancy in the affected organs. Clinical symptoms of TSC include cortical tubers and subependymal nodules in the brain, seizures, mental retardation, ungual and periungual fibromas, angiofibromas of the face, and angiomyolipomas in the kidneys [Roach, et al., 1999]. TSC displays genetic heterogeneity with two known loci: TSC1 on chromosome 9q34 [Fryer, et al., 1987a] and TSC2 on chromosome 16p13.3 [Kandt, et al., 1992]. The genes for both loci have been isolated and characterized [ The European Chromosome 16 Tuberous Sclerosis Consortium, 1993; van Slegtenhorst, et al., 1997]. The TSC1 gene contains 21 coding and two non-coding exons and encodes for an 8.6 kb mRNA. It spans 45 kb of genomic DNA and codes for hamartin, a 1,164 amino acid protein of 130 kDa. The TSC2 encodes for a 200 kDa protein, tuberin, and spans 43 kb of genomic DNA. The TSC2 gene consists of 41 coding exons and one non-coding exon and encodes for a 5.4 kb mRNA. Both genes are known to function as tumor suppressors [Carbonara, et al., 1994; Green, et al., 1994a; Green, et al., 1994b]. Several groups have performed mutation analysis of both the genes in patients mainly from the western and Japanese populations. A total of 133 mutations in the TSC1 gene and 350 mutations in the TSC2 gene have been reported so far (Human Gene Mutation Database; http://archive.uwcm.ac.uk/uwcm/mg/hgmd0.html). However, there is no report on the mutation analysis of the TSC genes from the Indian population. In this study, a total of 24 TSC cases were ascertained from the Indian population and a comprehensive mutation analysis of both the TSC genes was carried out in them to understand the function of both the genes, to locate important domains and also to find the mutational hotspots for molecular diagnosis of TSC. A total of 12 mutations, including seven novel mutations were identified. It was also shown that the most recurrent mutations (c.1831C>T and c.1832G>A) are, in part, due to methylation of the CpG dinucleotide. There are still 15-25% TSC cases in western populations with undetected mutations [Cheadle, et al., 2000a]. Further, there are familial TSC cases linked either to the TSC1 on 9q34 or TSC2 on 16p13.3 which fail to show any mutations in the coding sequences of both genes [Cheadle, et al., 2000a]. The failure to detect mutations in these cases could be due to several reasons. First, it could be that the mutations lie in the regulatory regions (promoters and enhancers) of both the genes, presently unidentified for the TSC1 gene [Cheadle, et al., 2000a]. Second, it is possible that the mutations lie outside of the coding sequences, within intronic sequences, or in the 5’ or 3’ UTRs [Cheadle, et al., 2000a]. Third, it may be due to the limitation of the techniques used to identify mutations [Cheadle, et al., 2000a]. In order to look for mutations in the promoter, the TSC1 gene promoter was characterized using luciferase reporter gene transfection assay. The promoter for the TSC2 gene is known [Kobayashi, et al., 1997]. The promoters of both TSC1 and TSC2 genes were sequenced in all the 24 cases to look for mutations. During the characterization of the TSC1 gene promoter, a novel isoform involving the non-coding exon 1 of the TSC1 gene was discovered serendipitously.

Eskom Holdings SOC Limited (referred to as Eskom), a public state owned company, is required to continually demonstrate environmental duty of care and report on its environmental performance. In furthering its commitment to sustainable development and in line with environmental compliance of its activities, Eskom is planning to have the Distribution Division certified against the International Organisation for Standardization (ISO) 14001:2004 environmental management system (EMS) standard by 2014. In general, management review may quickly turn into a dry review of the items on the agenda, done only to show an auditor the review was held. As such, the aim of this study was to assess the effectiveness of management reviews as one of the key continual improvement elements of the ISO 14001:2004 environmental management system within Eskom Distribution: Western Region. This research has been designed to take place in three stages. These stages are planning, execution and publication, and preparing the dissertation for marking. The research methodology included a literature study on various national and international articles and journals on EMSs that relate to environmental performance. The databases of Eskom Distribution: Western Region ‒ i.e. the management review presentation results for the 2008/09, 2009/10 and 2010/11 financial years, key significant environmental aspects for the Technical Service Centres (TSCs) and Minor/Major Engineering Works (MEW), key performance indicators (KPIs), Risk Audit System (RAS) results, and results of the external EMS audit conducted from 23–25 April 2007 were used for this research. Questionnaires were sent to the TSCs’ senior supervisors and Safety, Health, Environment and Quality (SHEQ) management. An analysis of the questionnaires completed by the TSC senior supervisors showed that all the participants have seen an improvement in environmental performance due to annual management reviews, except TSC11, who have not seen management review results. It can be concluded from the results of the SHEQ management questionnaires that an improvement (continual improvement as per the ISO 14001 requirement) was observed. The improvements were identified through improved processes, improved gap analysis, increased environmental awareness, and addressing risks. Most of the ISO 14001:2004 requirements for the management review for all financial years covered in this study were met. In terms of the objectives, targets and KPIs, Eskom Distribution: Western Region performed effectively and most of the outcomes were implemented according to the recommendations. Further, based on the external audit conducted from 23 to 25 April 2007, it is clear that Eskom Distribution: Western Region conformed to the minimum requirements of the ISO 14001:2004 EMS. Their management reviews also met all requirements of the ISO 14001:2004 relating to management review. This was proven by minutes of previous meetings that covered all the necessary issues that were audited. Thus, the existence of management reviews contributed towards ensuring that the ISO system was scrutinised and improved where it worked, and that aspects that did not work well were removed. / M. Environmental Management, North-West University, Potchefstroom Campus, 2014

Contexte : La sclérose tubéreuse de Bourneville (STB) affecte approximativement une naissance vivante sur 6000. Les principales sources de morbidité chez les enfants sont des manifestations cliniques affectant le cerveau et le cœur. Quant aux adolescents et aux adultes, ils sont à plus haut risque de développer des angiomyolipomes rénaux (AML) et la lymphangioléiomyomatose pulmonaire (LAM). Objectif : Ce projet de recherche a pour principal objectif de déterminer la capacité du fardeau de la maladie chez l’enfant à prédire le développement futur d’AML et de LAM chez l’adolescent et l’adulte. Méthodes : Les données sur 2420 participants de la TSC (Tuberous sclerosis complex) Alliance Natural History Database ont été utilisées pour développer des modèles de régression logistique afin de prédire les AML et la LAM. Ces modèles comptaient comme variables dix manifestations cliniques de la STB en plus du sexe biologique et de la mutation génétique. Les modèles développés ont été convertis en scores de risque clinique et une validation interne a ensuite été effectuée avec rééchantillonage par bootstrap afin d’évaluer leur performance prédictive à l’aide de mesures de discrimination et de calibration. Résultats : 1000 participants ont été diagnostiqués avec un AML, alors que la LAM a été détectée chez 107 participants. Les scores de risque clinique les moins élevés prédisaient des risques d’AML et de LAM de 0 % et de 5 %, tandis que les scores les plus élevés pouvaient prédire des risques allant jusqu’à 96 % et 54 %, respectivement. La performance prédictive des modèles allait de bonne à excellente (C-Index variant de 0,75 à 0,85). Conclusion : Les scores de risque clinique développés indiquent une bonne capacité des manifestations cliniques sélectionnées à prédire le risque futur des tumeurs, principalement pour les AML. Une validation externe devra cependant être menée afin de confirmer les résultats obtenus dans la présente étude. / Background: Tuberous sclerosis complex (TSC) affects approximately 1/6000 live births. The primary sources of childhood morbidity and mortality are manifestations affecting the brain and heart. Adolescents and adults, on the other hand, are at the greatest risk of developing renal angiomyolipoma (AML) and pulmonary lymphangioleiomyomatosis (LAM). Objective: The main objective of this research project is to determine the ability of the burden of TSC in children to predict the risk of developing AML and LAM in adults. Methods: Data from 2420 participants in the TSC Natural History Database were used to develop logistic regression models to predict AMLs and LAM. Variables used for the models included 10 clinical manifestations of TSC, in addition to biological sex and genetic mutation. The models were converted into clinical risk scores and were internally validated using bootstrap resampling to evaluate their predictive performance with the help of discrimination and calibration measures. Results: 1000 participants were diagnosed with AML, while LAM was seen in 107 participants. The lowest clinical risk scores predicted a risk of AML and LAM of 5% and 0%, while the highest scores predicted a risk of 96% and 54%, respectively. The predictive performance of the models ranged from good to excellent (C-Indexes of 0.75 to 0.85). Conclusions: The clinical risk scores indicated a good ability for the selected clinical manifestations to predict the future risk of tumours, particularly of AML. External validation of the risk scores will be important to confirm the robustness of our findings.

Thyristor switched capacitors (TSCs) have found an ever increasing role in the operation of flexible AC transmission systems or FACTS. The ability of these static var compensators to regulate the voltage by consuming or supplying reactive power quickly is not only viable for transmission but is an effective measure for increasing power quality at a distribution level. The proposed design uses a variable number of logically switched capacitors to supply reactive generation per reactive demand. The design ensures that the capacitors are safely switched into service, reactive demand is accurately calculated, and the TSC will respond quickly to changes in demand. While providing fast and safe operation, the conceptual design is also flexible enough to allow for optimization of the TSC to meet the demands of specific loads.

É apresentada neste trabalho a Técnica de Pulso Térmico com os aspectos teóricos envolvidos e a montagem do sistema experimental. A técnica é destinada à determinação do potencial de superfície, centróide de carga e carga total em filmes de polímeros. A técnica foi aplicada em conjunto com a de descarga termo estimulada em \"circuito-aberto\'\' ao estudo das propriedades de transporte e armazenamento de cargas em filmes de Teflon FEP (25?m) em diferentes situações: amostras virgens, tratadas termicamente, submetidas a radiação ultra violeta e amostras submetidas à descarga iônica a baixa pressão. Vários problemas foram levantados e alguns deles abordados segundo modelos teóricos simplificados na interpretação dos dados experimentais. / Theoretical experimental aspects of the Heat Pulse Technique (HPT) are presented. The applications were the measurements of surface potentials, charge centroid, and total charge of the film samples. No tentative was made to determinate the spatial distribution of the observed charges. The HPT was used as complement of TSC open circuits measurements in the study of conduction and polarization effects in 25?m Teflon FEP films for different initial conditions of the corona-charged samples: virgin samples, annealed, u.v. irradiated, and samples submitted to ionic glow discharge. Several problems were raised and some of them were treated using very simple theoretical models to interpret the experimental results.

This research work deals with the analysis, design and implementation of thyristor switched plain capacitor banks and thyristor switched shunt filter banks. Performances of various thyristor switched capacitor (TSC) topologies are also investigated by simulations. The theoretical findings have been verified by carrying out experimental work on two prototypes implemented within the scope of this research work, one is a wye-connected laboratory prototype and the other is a delta-connected application prototype integrated to some of the SVCs existing in Turkish Coal Enterprise s Plants. The advantages of back-to-back connected thyristor switches over conventional electromechanical contactors are also made clear by conducting an intensive experimental work in the laboratory. A good correlation have been obtained between theoretical and experimental results.

Submitted by Felipe Augusto Ferreira de Almeida null (felipeafalmeida@gmail.com) on 2016-12-20T16:56:04Z No. of bitstreams: 1 DISSERTACAO_FELIPE_FINAL.pdf: 3666708 bytes, checksum: 18899b06cbe9a7091fd3f037b0656174 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-22T10:53:09Z (GMT) No. of bitstreams: 1 almeira_faf_me_bauru.pdf: 3666708 bytes, checksum: 18899b06cbe9a7091fd3f037b0656174 (MD5) / Made available in DSpace on 2016-12-22T10:53:09Z (GMT). No. of bitstreams: 1 almeira_faf_me_bauru.pdf: 3666708 bytes, checksum: 18899b06cbe9a7091fd3f037b0656174 (MD5) Previous issue date: 2016-11-03 / Instituto Federal de Educação, Ciência e Tecnologia de São Paulo (IFSP) / Este trabalho aborda o emprego do Compensador Estático de Reativos (SVC) em redes de baixa tensão com geração distribuída de energia, tendo como objetivo a compensação de tensão e de fator de potência. Os principais distúrbios de qualidade de energia elétrica em baixa tensão, bem como as normas e os limites operacionais para os principais indicadores foram revisados, visando confrontação com as situações resultantes da integração do SVC no sistema elétrico. O SVC possui operação estabelecida como carga reativa controlável em sistemas de transmissão de energia, fazendo parte dos condicionadores da tecnologia FACTS (Flexible AC Transmission Systems). A exploração desta tecnologia em outro nível de tensão é o objetivo deste trabalho. As análises foram realizadas através de simulações computacionais, desenvolvidas no ambiente MATLAB, contemplando o desenvolvimento de modelos relacionados com aplicações de RCT (Reator Controlado a Tiristor), FC (Capacitor Fixo), do CCT (Capacitor Chaveado a Tiristor) e de um sistema de geração distribuída de energia elétrica trifásico em uma rede de baixa tensão a quatro fios. A metodologia para o dimensionamento dos elementos passivos dos condicionadores é apresentada, bem como a análise dos valores de potência reativa, fator de potência, distorções harmônicas e a avaliação da necessidade de utilização ou não de filtros passivos. A teoria da potência conservativa (TPC) é a metodologia utilizada para definição das grandezas elétricas e fatores de conformidade. Por fim, as características operacionais de um SVC aplicado a uma rede de baixa tensão a quatro fios são exploradas através dos resultados de simulação, com o objetivo de demonstrar a manutenção de suas características operacionais estabelecidas, no nível de baixa tensão, e apontar aspectos diferenciados quanto à regulação de fator de potência e da forma de tensão providos pelo SVC, para servir como informação de confronto frente a outras tecnologias comumente utilizadas neste nível de tensão. / This paper discusses the use of Static Var Compensator (SVC) on low voltage grids with distributed generation with the aim of voltage and power factor compensation. The main electrical power quality disturbances at low voltage as well as the rules and operational limits for the main indicators were reviewed aiming to confront the situations resulting from SVC integration in the electrical system. SVC has established operation as controllable reactive load in power transmission systems, being part of FACTS (Flexible AC Transmission Systems) technology conditioners. The application of this technology in another level of tension is the objective of this work. The analyzes were carried out through computer simulations developed in the MATLAB environment, including the development of models related to RCT (Thyristor Controlled Reactor), FC (Fixed Capacitor), CCT (Thyristor Switching Capacitor) and a threephase electric power distributed generation system in a four-wire low voltage grid. The methodology for the dimensioning of the passive elements of the conditioners is presented, as well as the analysis of the values of reactive power, power factor, harmonic distortions and the evaluation of the need to use passive filters. The conservative power theory (CPT) is the methodology used to define the electrical magnitudes and compliance factors. Finally, the operational characteristics of a SVC applied to a low-voltage four-wire network are exploited through the simulation results, in order to demonstrate the maintenance of its established operational characteristics at the low voltage level and to point out different aspects as well as the power factor regulation and voltage form provided by the SVC, to serve as confronting information.

É apresentada neste trabalho a Técnica de Pulso Térmico com os aspectos teóricos envolvidos e a montagem do sistema experimental. A técnica é destinada à determinação do potencial de superfície, centróide de carga e carga total em filmes de polímeros. A técnica foi aplicada em conjunto com a de descarga termo estimulada em \"circuito-aberto\'\' ao estudo das propriedades de transporte e armazenamento de cargas em filmes de Teflon FEP (25?m) em diferentes situações: amostras virgens, tratadas termicamente, submetidas a radiação ultra violeta e amostras submetidas à descarga iônica a baixa pressão. Vários problemas foram levantados e alguns deles abordados segundo modelos teóricos simplificados na interpretação dos dados experimentais. / Theoretical experimental aspects of the Heat Pulse Technique (HPT) are presented. The applications were the measurements of surface potentials, charge centroid, and total charge of the film samples. No tentative was made to determinate the spatial distribution of the observed charges. The HPT was used as complement of TSC open circuits measurements in the study of conduction and polarization effects in 25?m Teflon FEP films for different initial conditions of the corona-charged samples: virgin samples, annealed, u.v. irradiated, and samples submitted to ionic glow discharge. Several problems were raised and some of them were treated using very simple theoretical models to interpret the experimental results.