Academic literature on the topic 'Venda radio'
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Journal articles on the topic "Venda radio"
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McNeill, Fraser G. "MAKING MUSIC, MAKING MONEY: INFORMAL MUSICAL PRODUCTION AND PERFORMANCE IN VENDA, SOUTH AFRICA." Africa 82, no. 1 (January 19, 2012): 93–110. http://dx.doi.org/10.1017/s000197201100074x.
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ABSTRACTThis article presents an ethnographic analysis of the popular economy of informal musical production in the Venda region of South Africa. It focuses on the activities surrounding the Burnin' Shak Studio, a recording house that specializes in reggae music. Reliant on second-hand computers, pirated software, borrowed instruments, networks of trust and cycles of debt, musicians and producers in the Burnin' Shak occupy a distinctly peripheral position in South Africa's music industry. Unlike artists in the formal sphere of musical production, who sign deals with specific record labels, musicians in the informal sector seek out sponsors – usually young local businessmen – to fund their recordings with local producers. Marketing and distribution is the sole responsibility of the artist and the sponsor, who often develop a ‘patron–client’ relationship. And yet whilst the artists' entrepreneurial activity often earns them significant airplay on local radio stations, and associated cultural capital, the financial benefits are slim. In order to convert their cultural capital into cash, musicians in the informal sector must compete in the market for performances at government-sponsored shows. These shows are well funded by lucrative tenders, but they present musicians with a double-edged sword. To secure a contract with tender holders – or to entertain hopes of regular paid performances – musicians must ensure that these performances do not express critical political sentiment. As purveyors of a genre renowned for its critical social commentary, reggae musicians are particularly affected by this expectation of self-censorship. Informal musical production in the post-apartheid era thus affords musicians little artistic freedom. Rather, whilst the products of this culture industry may appear to be part of a ‘secondary’ economy, removed from the spheres of formalized production and control, they are in fact regulated and standardized through the process of tender allocation.
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Gonçalves, Marco Aurélio Carvalho, and Jairo Afonso Henkes. "IDENTIFICAÇÃO, RASTREABILIDADE E CERTIFICAÇÃO DE RESIDUOS SOLIDOS: UMA PROPOSTA PARA VALIDAÇÃO EM UM AMBIENTE UNIVERSITARIO HOSPITALAR." Revista Gestão & Sustentabilidade Ambiental 3, no. 1 (May 28, 2014): 373. http://dx.doi.org/10.19177/rgsa.v3e12014373-464.
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Identificação por Radiofreqüência (RFID) é uma tecnologia emergente, com um enorme potencial de aplicação na gestão de resíduos. Com esta tecnologia pode-se identificar objetos à distância por meio de etiquetas que transmitam dados por sinais de radio que podem ser processados e armazenados. Outra tecnologia com grandepotencial de retorno são aplicações baseadas em plataforma WEB que permitem uma maior interação entre as pessoas em tempo real. Com o crescimento das cidades,bem como dos custos para tratar os resíduos gerados, ferramentas que permitam uma melhor gestão, bem como estimulem a consciência ambiental dos geradores destes resíduos podem ter um impacto significativo nos custos, logística e outras necessidades que promovam o descarte correto e inteligente. Dentro deste contexto e aceitando o desafio de propor soluções criativas para aplicação em gestão de resíduos na área de saúde, este trabalho apresenta características de sistemas de RFID, a descrição de uma plataforma inteligente de gestão e um protótipo de um ambiente de interação, troca e venda de produtos baseada em uma moeda virtual para movimentação de produtos entre instituições. Os estudos são complementados pela descrição de uma arquitetura para gestão de RSS utilizando RFID, inteligência artificial e lixeiras inteligentes e a apresentação de um site baseado na plataforma WEB denominado"Clara.Responde", de forma que se possa verificar a adequação da metodologia proposta a um caso real.
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Oliveira, Luzilene Barbosa, Rafaela Maria Pessoa Nunes, Claudiana Mangabeira Santana, Antonia Rosa da Costa, Narcia Maria Fonseca Nunes, Iana Bantim Felicio Calou, Ana Paula Peron, Márcia Maria Mendes Marques, and Paulo Michel Pinheiro Ferreira. "Perfil do uso populacional de inseticidas domésticos no combate a mosquitos." Semina: Ciências Biológicas e da Saúde 36, no. 1 (November 6, 2015): 79. http://dx.doi.org/10.5433/1679-0367.2015v36n1p79.
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Esse trabalho descreve a utilização doméstica de inseticidas pela população de Picos (Piauí, Brasil), identificou quais são os tipos de inseticidas mais utilizados e descreve a incidência de intoxicação e a consciência ambiental da população. Após visitas domiciliares (n=700), notou-se que a maioria dos entrevistados foi representada por mulheres (75%), com idade entre 31-55 anos (49%), ensino fundamental incompleto (38,1%) e renda familiar entre 1-2 salários mínimos (64%). A maioria das residências tem entre 1-3 moradores (48%), 85% dos entrevistados usam inseticidas escolhidos principalmente em propagandas de TV e radio e apenas 54% leem o rótulo antes de aplicar o produto. A forma de apresentação mais usada é o aerossol (70,7%). A maioria (79%) reconhece que inseticidas são maléficos à saúde, mas 74% não usam nenhum Equipamento de Proteção Individual (EPI). Sintomas de toxicidade foram relatados por 27% dos entrevistados. Duas mulheres relataram irritação, tonturas e problemas respiratórios e necessidade de intervenção médica e internação hospitalar. Todos os entrevistados descartam as embalagens como lixo comum, uma vez que em Picos não há coleta seletiva. Em conclusão, a maioria das pessoas usam inseticidas, conhecem sobre os riscos individuais e coletivos aos quais estão expostos mas não usam EPI mesmo acreditando que sejam tóxicos. Notou-se que aquisição de conhecimentos não resulta, necessariamente, em mudanças de comportamento, uma vez que o conhecimento não se traduz em atitudes e práticas preventivas adequadas, ressaltando-se a necessidade de campanhas de conscientização quanto à toxicidade e aos riscos ambientais, capacitação de profissionais e política fiscalizatória contra a venda indiscriminada.
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Ufuk, Furkan. "Inferior Vena Cava Thrombosis in Behçet Disease." Radiology 292, no. 2 (August 2019): 288. http://dx.doi.org/10.1148/radiol.2019190351.
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Bednarova, Iliana, Claudia Frellesen, Andrei Roman, and Thomas J. Vogl. "Case 257: Leiomyosarcoma of the Inferior Vena Cava." Radiology 288, no. 3 (September 2018): 901–8. http://dx.doi.org/10.1148/radiol.2018160821.
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Gómez Tapia, Rita Fabiola. "ESTRATEGIA DE PROMOCIÓN PARA POSICIONAR UNA EMPRESA EN LA CIUDAD DE POTOSÍ." Revista Enfoques 3, no. 11 (July 1, 2019): 165–87. http://dx.doi.org/10.33996/revistaenfoques.v3i11.64.
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La Cristalería “Sissy” es una empresa potosina dedicada al servicio de flete y alquiler de cristalería y vajilla. El propósito de estudio que se desarrollo fueelaborar una estrategia de promoción para posicionar la Cristalería “Sissy” en la ciudad de Potosí, donde se utilizaron como métodos teóricos los siguientes: Análisis-síntesis, inductivo-deductivo, histórico-lógico y comparativo; entre los métodos empíricos se emplearon: la entrevista, encuesta y la observación. Los resultados del diagnóstico permitieron elaborar una estrategia de promoción basada en tácticas de la mezcla promocional (promoción de ventas, publicidad, relaciones públicas, venta personal y marketing directo) como ser: cupones, descuentos, premios de fidelidad, televisión, radio, periódico, internet, publicaciones, patrocinios, publicidad, capacitación a empleados y venta por catálogo. Como conclusión final se espera que la aplicación de la propuesta ayude a fortalecer el posicionamiento de la Cristalería “Sissy”.
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Pretorius, Pieter M., and Fergus V. Gleeson. "Case 74: Right-sided Superior Vena Cava Draining into Left Atrium in a Patient with Persistent Left-sided Superior Vena Cava." Radiology 232, no. 3 (September 2004): 730–34. http://dx.doi.org/10.1148/radiol.2323021092.
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Warshauer, David M., Richard K. Archer, Craig H. Selzman, Houman S. Tamaddon, and Matthew A. Mauro. "Case 115: Aortic Pseudoaneurysm from Penetrating Superior Vena Cava Stent1." Radiology 243, no. 3 (June 2007): 901–4. http://dx.doi.org/10.1148/radiol.2433040944.
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Trerotola, Scott O., and S. William Stavropoulos. "Management of Fractured Inferior Vena Cava Filters: Outcomes by Fragment Location." Radiology 284, no. 3 (September 2017): 887–96. http://dx.doi.org/10.1148/radiol.2017162005.
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Dinglasan, Lu Anne V., John C. Oh, J. Eric Schmitt, Scott O. Trerotola, Richard D. Shlansky-Goldberg, and S. William Stavropoulos. "Complicated Inferior Vena Cava Filter Retrievals: Associated Factors Identified at Preretrieval CT." Radiology 266, no. 1 (January 2013): 347–54. http://dx.doi.org/10.1148/radiol.12120372.
Full textDissertations / Theses on the topic "Venda radio"
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Alabi, Olushola John. "Effect of lysine to energy ratio on the productivity and carcass characteristics of indigenous Venda chickens aged one to thirteen weeks and raised in closed confinement." Thesis, University of Limpopo, 2013. http://hdl.handle.net/10386/1397.
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Thesis (Ph. D. (Animal Production )) -- University of Limpopo, 2013Eight experiments were conducted to determine the effect of dietary lysine to energy ratio on the productivity and carcass characteristics of indigenous Venda chickens aged one to thirteen weeks and raised in closed confinement. The eight experiments were based on four different energy levels of 11, 12, 13 and 14 MJ of ME/kg DM. Each dietary energy level had four different levels of dietary lysine (8, 9, 11 and 14 g lysine/kg DM). Thus, different dietary lysine to energy ratios were calculated. Experiments 1 to 4 determined the effect of dietary lysine to energy ratio on productivity of unsexed Venda chickens aged one to seven weeks. Each experiment commenced with 160 unsexed day-old indigenous Venda chicks with an initial live weight of 30 ± 3 g per bird and was carried out for seven weeks. In each experiment, the chicks were randomly assigned to four treatments with four replications, each having 10 chicks. A complete randomized design was used for each experiment. All data were analysed by one-way analysis of variance. Where there were significant differences, the Duncan test for multiple comparisons was used to test the significance of differences between treatment means. A quadratic regression model was used to determine the ratios for optimum productivity in each experiment while a linear model was used to determine the relationships between dietary lysine to energy ratio and optimal responses in the variables measured. Results indicated that dietary lysine to energy ratio for optimal responses depended on the variable of interest. In Experiment 1, feed intake, growth rate, live weight, ME intake and nitrogen retention were optimized at different dietary lysine to energy ratios of 0.722, 0.719, 0.719, 0.670 and 0.712, respectively. There was a positive and strong relationship (r2 = 0.950) between dietary lysine to energy ratio and feed conversion ratio (FCR). Results from Experiment 2 indicated that feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention were optimized at dietary lysine to energy ratios of 0.719, 0.742, 0.788, 0.742, 0.734 and 0.789, respectively. In Experiment 3, dietary lysine to energy ratio did not have any effect (P>0.05) on all the parameters measured. However, quadratic analysis indicated that dietary lysine to energy ratios of 0.817, 0.883, 0.920, 0.898, 0.895 and 0.955 optimized feed intake, growth rate, FCR, live weight, ME intake and nitrogen retention of the chickens, respectively. Experiment 4 results showed that feed intake, growth rate, FCR, live weight ME intake and nitrogen retention were v optimized at different dietary lysine to energy ratios of 0.906, 0.964, 1.023, 0.966, 0.963 and 0.951, respectively. Experiments 5 to 8 determined the effect of dietary lysine to energy ratio on productivity, carcass characteristics, sensory attributes and haematological values of female indigenous Venda chickens aged eight to thirteen weeks. The layouts, treatments, design and execution were similar to those described for Experiments 1, 2, 3 and 4, respectively, except that Experiments 5 to 8 were for female indigenous Venda chickens aged eight to 13 weeks. These chickens were different from those used in Experiments 1 to 4. They were raised on a grower mash (16 % crude protein, 11 MJ of ME/kg DM and 180 g of lysine) prior to commencement of the study. Each experiment commenced with 120 eight weeks old female Venda chickens with an initial live weight of 412 ± 3 g per chicken. In each experiment, the chickens were randomly assigned to four treatments with five replicates, each having six chickens. Results obtained from Experiment 5 showed that feed intake, growth rate, FCR, live weight, ME intake, carcass weight, dressing percentage, breast meat, drumstick, wing weight, breast meat drip loss, juiciness, flavour, haemoglobin and pack cell volume were optimized at different dietary lysine to energy ratios of 0.672, 0.646, 0639, 0.649, 0.655, 0.656, 0.664, 0.669, 0.665, 0.663, 0.631, 0.708, 0.623, 0.556 and 0.609, respectively. In Experiment 6, the diets were formulated to have higher lysine to energy ratios than those in Experiment 5 by using a dietary lysine level of 9 g lysine/kg DM. Results from this experiment showed that feed intake, FCR, nitrogen retention, carcass weight, dressing percentage, breast meat, gizzard weights and breast meat pH at 2, 12 and 24 hours after slaughter were optimized at dietary lysine to energy ratios of 0.798, 0.613, 0.777, 0.742, 0.753, 0.729, 0.758, 0.752, 0.802 and 0.797, respectively. Red blood cell and haemoglobin values in this experiment were optimized at dietary lysine to energy ratios of 0.480 and 0.624, respectively. In Experiment 7, dietary lysine to energy ratios of 0.79, 0.85, 0.92 and 1.00 g lysine/ MJ of ME were used. Dietary treatments in this experiment had no effect (P>0.05) on all the production parameters measured except feed and apparent metabolisable energy intakes. Quadratic analysis of the results indicated that dietary lysine to energy ratios of 0.964, 0.912, 0.900, 0.890, 0.910, 1.090, 0.934 and 0.895 optimized feed intake, apparent metabolisable energy, carcass, breast meat, drumstick weights and vi breast meat drip loss, juiciness and flavour, respectively. A positive and very strong relationship (r2 =0.998) was observed between dietary lysine to energy ratio and pack cell volume. Experiment 8 diets were formulated to have higher dietary lysine to energy ratios than the other experiments. Results of this experiment indicated that all the production parameters were influenced (P<0.05) by dietary lysine to energy ratio except mortality. Feed intake, growth rate, feed conversion ratio, live weight, apparent metabolisable energy and nitrogen retention were optimized at dietary lysine to energy ratios of 0.996, 0.980, 0.991, 1.010, 0.957 and 0.993, respectively. Dietary lysine to energy ratios of 0.992, 0.974, 0.991, 0.992, 1.023, 0.981, 0.979 and 0.815 optimized carcass weight, dressing percentage, breast meat, drumstick, liver weights and breast meat tenderness, juiciness and flavour, respectively. There were variations in the optimal lysine to energy ratios for different parameters investigated. In a diet containing 8 g of lysine per kg DM, 11.13 MJ of ME/kg DM and 150 g of CP/kg DM, dietary lysine to energy ratios of 0.719 and 0.649 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 9 g of lysine per kg DM, 12.13 MJ of ME/kg DM and 180 g of CP/kg DM, dietary lysine to energy ratios of 0.742 and 0.712 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. In a diet containing 11 g of lysine per kg DM, 12.51 MJ of ME/kg DM and 220 g of CP/kg DM, dietary lysine to energy ratios of 0.878 and 0.894 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks respectively. In a diet containing 12 g of lysine per kg DM, 12.05 MJ of ME/kg DM and 240 g of CP/kg DM, dietary lysine to energy ratios of 0.996 and 1.010 are recommended for optimal live weight of Venda chickens aged one to seven and eight to 13 weeks, respectively. The results obtained in this study showed that different production parameters of Venda chickens were optimized at different lysine to energy ratios. This implies that the nutritional requirements of these chickens are dynamic and thus, dietary lysine to energy for optimal production depends on the production parameter of interest. This has implications on ration formulation for indigenous chickens.
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Gondim, Priscylla Cinthia Alves. "Desenvolvimento de bloco de veda??o com barita na composi??o de partida para blindagem de radia??o X." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12744.
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Previous issue date: 2009-08-21Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
This work main objective is to study the use of bricks in barium X-rays rooms in order to contribute to the optimization of shielding rooms diagnosis. The work was based on experimental measurements of X-ray attenuation (40 to 150 kV), using ceramic seal bearing the incorporation of barium sulfat (BaSO4). Different formulations were studied in three different firing temperatures and evaluated for incorporation in the ceramic body. The composition of 20% of barite processed at a temperature of 950 ? C showed better physical and mechanical properties, is considered the most suitable for the purpose of this work. Were produced bricks sealing composition formulated based on that presented the best technological features. These blocks were tested physically as a building material and wall protective barrier. Properties such as visual, deviation from the square, face flatness, water absorption and compressive strength were evaluated for all the blocks produced. The behavior of this material as attenuator for X-rays was investigated by experimental results which take into account mortar manufacturers barium through the different strains and compared with the reference material (Pb). The simulation results indicated that the ceramic block barium shows excellent properties of attenuation equivalence lead taking into account the energy used in diagnostic X-ray
Este trabalho tem por finalidade principal estudar a utiliza??o de blocos cer?micos baritados em salas de radia??o X, visando contribuir para a otimiza??o da blindagem de salas de diagn?stico. O trabalho foi baseado em medidas experimentais de atenua??o da radia??o X (40 a 150 kV), empregando material cer?mico de veda??o contendo a incorpora??o de sulfato de b?rio (BaSO4). Diferentes formula??es foram estudadas em tr?s temperaturas de queima diferentes e avaliadas as incorpora??es na massa cer?mica. A composi??o de 20% de barita processada a temperatura de 950?C, apresentou melhores propriedades f?sicas e mec?nicas, sendo considerada a mais adequada para a proposta deste trabalho. Foram produzidos blocos cer?micos de veda??o baseados na composi??o formulada que apresentou melhores caracter?sticas tecnol?gicas. Estes blocos foram testados fisicamente como material construtivo de parede e barreira protetora. Propriedades como caracter?sticas visuais, desvio com rela??o ao esquadro, planeza das faces, absor??o de ?gua e resist?ncia ? compress?o foram avaliadas para todos os blocos produzidos. O comportamento deste material como atenuador para a radia??o X foi investigado por meio de resultados experimentais que levaram em considera??o fabricantes de argamassas baritadas atrav?s das diferentes tens?es e comparado com o material de refer?ncia (Pb). Os resultados obtidos nas simula??es indicaram que o bloco cer?mico baritado demonstra ?timas propriedades de atenua??o em equival?ncia ao chumbo levando-se em conta as energias usadas em raios X diagn?stico
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Moraes, Renan Manhabosco. "Aplicações de técnicas multivariadas na área comercial de uma empresa de comunicação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/173130.
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A mudança de comportamento dos consumidores através do advento da tecnologia e das redes sociais gera um grande empoderamento dos mesmos, alterando substancialmente a forma de relacionamento das empresas com seu público final. Atentas a este mercado, as empresas de mídia passam por profundas mudanças, tanto do ponto de vista da entrega de conteúdo ao seu público, quanto no seu formato administrativo, estratégico e financeiro. Sendo assim, a presente dissertação apresenta abordagens apoiadas em técnicas multivariadas para composição de equipes comerciais e de remuneração dos times de venda de uma empresa de comunicação. No artigo 1, objetiva-se gerar um modelo para estimar a premiação comercial das equipes de venda das rádios do Grupo RBS. Para tanto, inicialmente geram-se agrupamentos das emissoras de rádio do Grupo RBS no estado do Rio Grande do Sul e de Santa Catarina com base nos seus perfis de similaridades. Para cada cluster gerado, gera-se uma regressão linear múltipla da premiação comercial validado através de validação cruzada por intermédio do R2 ajustado e Mean Absolute Percentage Error (MAPE). O segundo artigo aborda a clusterização dos top clientes do Grupo RBS e o impacto na composição das equipes comerciais por meio do método da seleção de variáveis. As 7 variáveis originais foram avaliadas através do método de seleção de variáveis “Omita uma variável por vez”; o melhor Silhouette Index (SI) médio, métrica utilizada para avaliar a qualidade dos agrupamentos gerados, foi obtido quando 3 variáveis foram retidas. Os agrupamentos gerados por tais variáveis refletem o comportamento de compra de mídia dos clientes; os agrupamentos foram considerados satisfatórios quando avaliados por especialistas do Grupo RBS.The change in the behavior of consumers with the advent of technology and social networks generates a great empowerment of themselves, substantially altering the relationship form of companies to their final audience. Attentive to this market, media companies undergo profound changes, both from the point of view of delivering content to their audience, as well as in their administrative, strategic and financial format. Thus, the present dissertation presents approaches supported by multivariate techniques for the composition of commercial and remuneration teams of the sales group of a communication company. In article 1, the objective is to generate a model to estimate the commercial awards of the sales teams of the RBS Group radios. To do this, we initially generate groupings of radio stations from the RBS Group in the state of Rio Grande do Sul and Santa Catarina based on their profiles of similarities. For each cluster generated, a multiple linear regression of the commercial award is generated, validated through cross validation through the adjusted R2 and Mean Absolute Percentage Error (MAPE). The second article addresses the clustering of RBS Group top clients and the impact on the composition of business teams through the variable selection method. The original 7 variables were evaluated through the variable selection method "Omit one variable at a time"; the best Silhouette Index (SI) average, metric used to evaluate the quality of the generated clusters, was obtained when 3 variables were retained. Clusters generated by such variables reflect customers' buying behavior of media; the clusters were considered satisfactory when evaluated by RBS Group experts.
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Tshamano, Ndwamato Walter. "Radio drama : a critical study of some radio Venda broadcasts." Thesis, 1993. http://hdl.handle.net/10386/2125.
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Mukosi, Thilivhali. "Language use in media discourse : the case of Nḓevhetsini news commentary on Phalaphala FM." Diss., 2020. http://hdl.handle.net/10500/26771.
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Text had abstracts in English and Tshivenda.
No keywordsVery few scholars have ventured into language use in media discourse, especially in African Languages. The purpose of this study was to determine the language use in media discourse in the Nḓevhetsini Programme on Phalaphala FM, to investigate linguistic elements that create challenges amongst presenters, reporters, listeners and guest speakers and also the manner in which the message is received by listeners. This study employed a qualitative approach to obtain data from Nḓevhetsini episodes. The episodes were divided into themes identified in order to compare common cases and those that differ in language use amongst presenters, reporters, compilers, listeners and guest speakers engaged on the Nḓevhetsini episodes. The study found that borrowing, code-mixing, dialectal variants use, and not interpreting the English message to listeners bring challenges in language use in media discourse. Language programmes that promote language should be implemented. Rules that guide language use are important in language preservation.
A hu athu tou vha na vhaḓivhi vha maṅwalwa vhe vha sedzulusa kushumisele kwa luambo kha nyanḓadzamafhungo nga maanḓa kha ngudo ya Nyambo dza Vharema. Ndivho ya ngudo yo vha u ṱoḓa u wanulusa kushumisele kwa luambo kha nyanḓadzamafhungo kha mbekanyamushumo ya Nḓevhetsini, ho sedzwa zwiteṅwa zwa luambo zwine zwa vha fha khaedu khathihi na u sedza uri mulaedza u swika nga nḓilaḓe kha vhathetshelesi. Ngudo iyi yo shumisa ngona ya Khwaḽithethivi kha u kuvhanganya mafhungo u bva kha episode ṱhanu. Episode dzo saukanywa u ya nga thero dzo wanalaho hu u itela u ita mbambedzo dza kushumisele kwa luambo dzi fanaho na dzi sa faniho. Ngudo iyi yo wanulusa uri u hadzima, u ṱanganyiswa ha maipfi kana mafurase a nyambo dzo fhambanaho, na u sa pindulelwa ha milaedza ya English ndi khaedu. Milaedza i hashiwaho nga English i ṋea vhathetshelesi khaedu kha kushumisele kwa luambo kha khasho. Mbekanyamushumo na milayo i ṱuṱuwedzaho tshumiso ya Tshivenḓa zwi tea u sikiwa.
African Languages
M.A. (African Languages)
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Netshitomboni, Rabelani Lusani. "The role of public service broadcasting in South African education : Phalaphala FM as a case study." 1999. http://hdl.handle.net/10500/15618.
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DissertationThis study investigates the role of radio in South African education, with Phalaphala FM as a case study. The aim was to investigate the extent to which Phalaphala FM's programmes include educational material and the extent to which the respondents listen to Phalaphala FM to satisfy their educational needs. Phalaphala FM as a regional radio station predominantly serves rural listeners, as they often do not have access to alternative forms of media. The theoretical point of departure is the uses and gratifications with its emphasis on the active audience concept. Content analysis of Phalaphala FM' s programme schedule was conducted to determine the amount of educational material. Focus group interviews and survey research were used to determine the respondents' media usage patterns. The results indicate that entertainment programmes are given more time on Phalaphala FM and that the respondents prefer entertainment programmes, to informational and educational programmes.
Educational Studies
M.A. (Communication)
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Mashau, Pfunzo Lawrence. "An exploration of the implementation of language policies for community radio stations in Vhembe District of Limpopo Province." Diss., 2019. http://hdl.handle.net/11602/1443.
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MA (Linguistics)Department of Communication and Applied Languages Studies
The question of the use of languages in radio broadcasting is of particular importance in multilingual communities in Vhembe district of Limpopo province. The Independent Communications Authority of South Africa (ICASA) issues broadcasting licenses, and further regulates conditions of implementation of these licenses. The purpose of this study is to explore the extent to which community radio stations in Vhembe district adhere to ICASA language policies and guidelines stipulated in their licenses. Literature was drawn from government language policy documents (Acts, rules and regulations), broadcasting legislative framework manuals (ICASA), government gazettes, books, journals, magazines, and newspapers. The design for the study is exploratory, whereas the target population comprised of seven (7) community radio stations, fifteen (15) radio programmes, and station managers of community radio stations in the Vhembe district. Purposive sampling was used to select three community radio stations, three programmes per station and station manager of each sampled station. Non-participant observation, documents analysis and tape recorder were used as instruments for data collection, whereby the researcher observed, recorded a total of (nine) 9 talk format programmes. The researcher further analysed documents (broadcasting licenses and programme schedules), from sampled radio stations, to examine stipulated language quotas by ICASA. Lastly, the researcher employed unstructured interviews to collect data from the station managers of community radio stations, in the Vhembe district. The sampled data was analysed through qualitative content analysis and interpreted subsequently. Findings from data analysis determined that community radio stations partially adhere to the policies stipulated in their licenses.
NRF
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Mbajiorgu, Christian A. "Effect of dietary energy to protein ratio level on growth and productivity of indigenous Venda chickens raised in closed confinement from one up to 13 weeks of age." Thesis, 2010. http://hdl.handle.net/10386/318.
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Thesis (M.Sc. (Agriculture)) --University of Limpopo, 2010Ten experiments were conducted to determine the effect of dietary energy to protein ratio level on growth and productivity of indigenous Venda chickens raised in closed confinement from day-old up to thirteen weeks of age. The ten experiments were based on five different energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM. Each dietary energy level had five different levels of protein concentrations of 220, 190, 180, 170 and 160 g/kg DM, thus ending up with twenty five different dietary energy to protein ratio levels. Experiments 1 to 5 examined the effect of dietary energy to protein ratio on productivity of unsexed Venda chickens aged one to six weeks. Experiments 1 to 5 each commenced with 160 unsexed day-old indigenous Venda chicks with an initial weight of 25 ± 2 g per bird and each lasted for a period of six weeks. In each experiment, the chicks were randomly assigned to five treatments with four replications, each having eight birds. Thus, 20 floor pens (1.5 m2 /pen) were used in total for each experiment. All the five experiments were carried out around the same time. A complete randomized design was used for each experiment. A quadratic regression model was used to determine the ratios for optimum feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention in each experiment while a linear model was used to determine the relationship between optimal responses in the above variables and dietary energy to protein ratio levels. Dietary energy to protein ratio level for optimal response for any variable was relative and depended on the energy to protein ratio values of the diet. Energy to protein ratios of 63, 67, 70, 74 and 78 MJ ME/kg protein promoted optimal live weights of 415, 408, 370, 365 and 344 g at six weeks of age for diet energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM, respectively. However, optimal response trends for different variables were also influenced by the dietary energy to crude protein ratio. Optimal feed intake increased linearly with increasing dietary energy to protein ratio levels. Similarly, optimal metabolisable energy level increased linearly with increasing dietary energy to protein ratio levels without any increase in live weight. On the other hand, increasing dietary energy to protein ratio level decreased growth rate with a linear deteriorating feed conversion ratio,thus, negatively affecting live weight of the chickens at six weeks of age. However, increasing dietary energy to protein ratio levels improved efficiency of protein utilization with a linear deteriorating metabolisable energy utilization. In experiments 1 to 5, correlation analysis indicated that optimal feed intake, feed conversion ratio and metabolisable energy level were positively and strongly correlated with dietary energy to protein ratio levels while optimal live weight, growth rate and nitrogen retention were negatively and strongly correlated with dietary energy to protein ratio levels. The study indicated that a diet containing a crude protein content level of 178 g/kg DM and an energy level of 14 MJ ME/kg DM allowed for optimal utilization of absorbed protein and energy for growth in unsexed indigenous Venda chickens aged between one and six weeks. Experiments 6 to 10 examined the effect of dietary energy to protein ratio level on productivity of male Indigenous Venda chickens raised in closed confinement from seven up to 13 weeks of age. Each experiment commenced with 100 seven-week old male Venda chickens with an initial weight of 320 ± 2 g per bird. In each experiment, the chickens were randomly assigned to five treatments with four replications, each having five birds. Thus, 20 floor pens (1.5 m2/pen) were used in total for each experiment. All the five experiments were carried out around the same time and for a period of seven weeks. A complete randomized design wasused for each experiment. A quadratic regression model was used to determine energy to protein ratios for optimum feed intake, growth rate, feed conversion ratio,live weight, metabolisable energy, nitrogen retention, carcass yield, breast meatyield and fat pad deposition in each experiment while a linear model was used to determine the relationship between optimal responses of the above variables and dietary energy to protein ratio levels. Energy to protein ratios of 60, 71, 66, 72 and 71 MJ ME/kg protein promoted optimal live weights of 1167, 950, 983, 1235 and 1172 g at thirteen weeks of age for diet energy levels of 12.2, 13, 13.2, 13.4 and 14 MJ ME/kg DM, respectively. Optimal response trends in feed intake, growth rate, feed conversion ratio, nitrogen retention, and metabolisable energy intakes in male Venda chickens tended to increase with increase in dietary energy to protein ratio level. In contrast, optimal carcass and breast meat yield tended to decrease with increasing dietary energy to protein ratio level. However, optimal live weight and fat pad remained unchanged with increase in dietary energy to protein ratio value. Additionally, increasing dietary energy to protein ratio level improved efficiency of protein utilization with deteriorating metabolisable energy utilization.On the other hand, experiments 6 to 10 showed that optimal feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy level, nitrogen retention and fat pad were positively and poorly correlated with dietary energy to protein ratio levels while optimal carcass weight and breast meat yield were negatively and poorly correlated with dietary energy to protein ratio levels This study indicated that a diet containing 193 g CP/kg DM and an energy level of 14 MJ ME/kg DM allowed for optimal utilization of absorbed protein and energy for growth in male indigenous Venda chickens aged between seven and thirteen weeks.It is, therefore, concluded that optimal response trends for different variables in growing unsexed Venda chickens offered diets differing in optimal dietary energy to protein ratio levels are influenced by the diet crude protein content rather than the feed energy level per se. Diets containing decreased dietary energy to protein ratio levels may promote improved growth rate and efficient feed conversion ratio while naturally restricting feed intake. Diets containing increased dietary energy to protein ratio levels favoured efficient utilization of consumed dietary protein. However, with such diets, protein became limiting and birds increased their feed intake attempting thereby to obtain more of the limiting protein in order to meet their protein requirement regardless of the energy value of the diet.It is, also, concluded that growing male Venda chickens increased their feed intake with increase in dietary energy to protein ratio. This is contrary to what has been observed in broiler chickens which decrease their intake with increase in diet energy value. It is suggested that this might reflect the differences between indigenous and broiler chickens in terms of their genetic and physiological abilities to regulate their feed intakes according to dietary energy levels.
National Research Foundation (NRF)
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Baptista, Henrique Maria Bruges Oliveira Ferreirinha. "Operações de venda de NPLs : uma visão geral ao abrigo do regime jurídico português." Master's thesis, 2020. http://hdl.handle.net/10400.14/33862.
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As operações de venda de portfólios de NPL têm despenhado um papel fundamental nas atividades de desalavancagem dos bancos europeus, com o volume de carteiras transacionadas durante o ano de 2019 a atingir o valor de 102.4 mil milhões de euros na Europa.
Embora as instituições de crédito disponham frequentemente de carteiras de NPL através de estruturas de venda bilateral, nos últimos anos tem-se registado um número cada vez maior de operações de titularização neste mercado. Tanto a venda direta de carteiras como a titularização têm características semelhantes e servem propósitos idênticos. No entanto, elas devem ser vistas como operações complementares à luz das suas diferentes características.
Neste trabalho proponho-me a analisar os principais aspetos das figuras da cessão de créditos e da titularização de créditos enquanto estruturas jurídicas subjacentes à transmissão de portfólios de NPL em Portugal, comparando-as sempre na perspetiva da particular natureza não produtiva dos ativos transacionados, e dos objetivos que as partes procuram atingir com a operação.NPL portfolios sales have been playing a key role in the deleveraging activities of European banks, with the volume of portfolios traded during the year of 2019 reaching 102,4 billion euros in Europe. Although credit institutions often dispose of their NPL portfolios through outright sales, in recent years there has been an increasing number of NPL securitizations. Both direct sales of portfolios and securitization have similar characteristics and pursue identical purposes. However, they should be seen as complementary structures in light of their different characteristics. In this paper I propose to analyze the core aspects of the assignment of credits and securitization as the underlying legal structure for the transfer of NPL portfolios in Portugal, comparing them from the perspective of both the particular non-performing nature of the assets to be transferred and the objectives that the parties seek to achieve with the operation.
Books on the topic "Venda radio"
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La voz que venía del frío: Radio Moscú : Eusebio Cimorra, 1939-1977. Valladolid: Ámbito, 2010.
Find full textBook chapters on the topic "Venda radio"
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Hatanaka, Tetsuo, Rokuro Shiba, Michihiko Fukui, Masami Yoshioka, Eiichi Chihara, and Yoshifumi Tanaka. "Pressure Pulse Transmission Ratio (PPTR) of Inferior Vena Cava and the Blood Volume Status." In Computing and Monitoring in Anesthesia and Intensive Care, 321–23. Tokyo: Springer Japan, 1992. http://dx.doi.org/10.1007/978-4-431-68201-1_101.
Full textConference papers on the topic "Venda radio"
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Luo, Yin, Philippe Enkababian, Leah Hrab, Anas Najy, Ahmed Shokry, Ahmed Berrim, Arlen Sarsekov, Andika Sulaiman, and Bulat Kamaletdinov. "Diverting from the Status Quo: Leveraging Acid Retardation for Production Enhancement in Offshore Carbonates in UAE." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206154-ms.
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Abstract With the expanding offshore rig activity in United Arab Emirates leading to an increased number of horizontal wells and longer drains, coupled with changing rock fabrics, it became imperative to diverge from the existing stimulation methods to deliver more consistent and reliable results. These results were achieved via the introduction of single-phase retarded acid (SPRA) and viscoelastic diverting acid (VEDA) to both active and shut-in wells offshore. The introduction of SPRA and VEDA was possible after extensive laboratory testing including core flow tests, solubility tests, emulsion tendency testing, and corrosion inhibition tests to evaluate and benchmark the performance of these blends in comparison to the existing acid recipes such as plain HCl and polymer-based diverted acid. These tests showed that a combination of SPRA and VEDA would allow maximizing lateral coverage and enhance acid penetration due to the reduced rate of reaction and chemical diversion capabilities from thief zones. Combining the introduction of SPRA and VEDA with a shift to bullheading and higher pumping rates enabled the delivery of previously unachievable production results at sustainable wellhead pressures or even well revival of shut-in wells. In addition, reduction of acid content for dolomite stimulation was possible due to the implementation of acid retardation, which also allowed protecting wellheads from exposure to higher acid concentrations while bullheading. Treatment parameters such as volumes, rates, and acid/diverter sequence and ratio were then adjusted for optimal wormhole penetration across all zones using a new carbonate matrix acidizing modeling software. Post-treatment evaluation for the cases of previously shut-in wells has proven the success of the SPRA and VEDA combination. Shut-in wells that were unable to produce sustainably at the required tubing-head pressure (production flowline pressure), were able to produce sustainably with a 100% increase in production compared to prestimulation testing. Similarly, for gas wells, the combination of SPRA and VEDA resulted in a 50% increase in production at a similar bottomhole pressure. In addition, water injectors have also exhibited sustainably increased levels of injectivity compared to prestimulation levels, leading to better sweepage. The novelty of this paper is the comparison between historical carbonate stimulation results in UAE using plain HCl acid with polymer-based diverted acid and using SPRA with VEDA. It also sheds light on the game-changing solutions that suit the ever-increasing challenges observed in offshore oil and gas wells including well placement, lithology, permeability contrast, and type of hydrocarbon within the various target sublayers.
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Ahmad, Rashidi, Mohamad Iqhbal Kunji, Meera Mohaideen Hj Abd Kareem, and Shamimi A. Halim. "New approach of assessing hypovolemic shock class 1 during acute emergencies: Ultrasonographic inferior vena cava and abdominal aorta diameter ratio." In INTERNATIONAL CONFERENCE ON MATHEMATICAL SCIENCES AND STATISTICS 2013 (ICMSS2013): Proceedings of the International Conference on Mathematical Sciences and Statistics 2013. AIP, 2013. http://dx.doi.org/10.1063/1.4823951.
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Barrows, Sean T., Ravishankar Balasubramian, and Jen-Ping Chen. "Investigation of Tip Clearance Modeling Techniques for a Transonic Compressor Rotor." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-60136.
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Computational fluid dynamics (CFD) codes are becoming an integral part of the design and analysis process involved with creating and improving upon new engine designs. This necessitates the investigation and development of accurate modeling techniques for flow simulations with a quick turn around time of typically 48 hours. The present paper is focused on increasing the fidelity of compressor rotor simulations by examining three rotor tip clearance modeling techniques. The first approach models the tip clearance region as a loss-less, periodic, un-gridded region as first proposed by Kirtley et al. The second approach is a modification of this technique to study the vena-contracta effects. The tip clearance region remains un-gridded, but, the physical radial depth of tip clearance is gradually reduced to the smallest constriction typically seen in the tip clearance because of flow phenomena such as the shroud and blade-tip boundary layers. The final approach is a completely gridded tip clearance region of full depth to verify the vena-contracta approach as well as to determine if any increase in fidelity is achieved through this computationally costly procedure. These three tip clearance modeling approaches are applied to the NASA transonic compressor rotor, Rotor-35, in a rotor only configuration and the predicted operational ranges are compared to available LDV data. Span-wise performance characteristics such as total pressure ratio and total temperature ratio are compared at a near peak efficiency and at a near-stall operating point. Tip-vortex resolution and predictions are also examined. The merits and demerits of the three approaches are discussed and recommendations are made for a viable approach in terms of accuracy and computational resources.
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Ohtake, Hiroyasu, Masato Hagiwarai, and Yasuo Koizumi. "Experimental and Analytical Studies on Frictional Pressure Drops of Gas-Liquid Two-Phase Flow at Vena Contract and Expansion." In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62363.
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The frictional pressure drops of gas-liquid two-phase flow in mini-micro pipes and at vena contract and expansion were investigated experimentally and analytically. Pressure drops of straight pipe, sudden enlargement and sudden contraction of gas-liquid two-phase flow in mini-pipes were measured. Test liquid was water at room temperature; test gas was argon. The diameter of the test mini-pipe was 1.0 and 0.5 mm, respectively. Each test tube was connected at both ends to small tanks. The diameter of the small tank was 15 mm for 1.0 mm diameter of test tube and 5 mm for 0.5 mm diameter of test tube, respectively. Thus, the cross-sectional ratio of the contraction was about 1000; the ratio of the enlargement was about 0.001. The pressure drop data were collected over 3.0 < UG < 130 m/s for the superficial gas velocity and 0.02 < UL < 6.0 m/s for the superficial liquid velocity. The present experimental results of sudden contraction pressure loss factor Kc and sudden enlargement pressure loss factor Ke of single-phase liquid flow in mini-pipes differed from the conventional values, Kc = 0.5 and Ke = 1.0. The calculated results by using a commercial code, STAR-CD, agreed with the present experimental results for mini-pipes. Assuming to homogenous flow and incompressible flow, sudden contraction pressure loss, sudden enlargement pressure loss and their factors Kc, Ke for gas-liquid two-phase flow were estimated by using momentum equation and energy equation. The contraction pressure losses by Hewitt’s correlation for conventional pipes were similar to the present experimental results of the contraction for mini-circular pipe. Collier’s correlation of the enlargement pressure loss for conventional pipes underpredicted the present experimental results of the enlargement for mini-tube. Based on the present experimental results, new correlations were obtained for the enlargement and the contraction pressure losses in mini-channel.
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Willinger, Reinhard, and Hermann Haselbacher. "On the Modeling of Tip Leakage Flow in Axial Turbine Blade Rows." In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0633.
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The starting point of this paper is an established turbine tip leakage loss model based on energy considerations. The model requires a discharge coefficient as an empirical input. The discharge coefficient is the ratio of the actual to the theoretical tip gap mass flow rate, The nondimensional parameters influencing the discharge coefficient are determined by a dimensional analysis. These parameters are: gap width to length ratio, end wall speed to gap flow velocity ratio and gap Reynolds number. Ranges for these parameters, valid for typical turbine tip gap situations, are presented. The numerical investigation of the turbulent flow in a plane perpendicular to the blade chord line supplies the discharge coefficient versus the nondimensional gap width. Depending on the gap width to length ratio, various degrees of mixing of the flow downstream of the vena contracta can be detected. Based on these observations, a simple tip gap flow model is presented. The discharge coefficients computed by this model are compared with the numerical results as well as with experimental values from the literature. Finally, the model is used to calculate the discharge coefficients of improved tip gap geometries (squealers, winglets).
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Prekker, Matthew E., Nathaniel L. Scott, Danielle Hart, Jose Luna, Mark D. Sprenkle, and James W. Leatherman. "Ultrasound Measurement Of Inferior Vena Caval Diameter Is More Accurate Than The Internal Jugular Vein Aspect Ratio To Estimate Central Venous Pressure In ICU Patients." In American Thoracic Society 2010 International Conference, May 14-19, 2010 • New Orleans. American Thoracic Society, 2010. http://dx.doi.org/10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a4580.
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Ramakrishna, P. V., and M. Govardhan. "Effect of Tip Clearance on the Performance of Forward Swept Subsonic Axial Compressor Rotors at High Stagger Angles." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65103.
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Tip leakage phenomenon in axial compressors is sensitive to the flow incidence, flow coefficient, tip gap height and the pressure gradients. All these geometric/flow features are considerably altered by blade stagger angle. Literature on the stagger angle effects in compressors is scarce; and indeed, such studies for various tip gap heights have not been reported yet. The present paper reports the effect of rotor stagger angle on the performance of subsonic axial compressor rotor with different forward sweep configurations and for various rotor tip clearances. The computational model for the study utilizes finest hexahedral grids. A commercial CFD package ANSYS® CFX 11.0 was used with standard k-ω turbulence model for the simulations. CFD results were well validated with experiments. The following observations were made: At higher stagger angles, flow separates from upstream suction surface locations. Little tip clearance had a positive effect for certain stagger angle increments owing to beneficial interaction of leakage flows with the local flow field. However, severe performance loss was observed at higher stagger settings with large clearances. As the stagger angle was increased, vena contracta effect was highly reduced. At high stagger angles, the flow was observed to leak in a more “axially-reversed” fashion through the tip gap. The deep lowest pressure zones near the pressure surface of the tip are due to the effect of ‘vena contracta.’ Such zones near the suction surface edge of the tip are due to flow acceleration. This particular feature is directly correlated with the tip aerofoil loading and thickness-to-tip gap ratio.
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Doğu, Yahya, Mustafa C. Sertçakan, Ahmet S. Bahar, Altuğ Pişkin, Ercan Arıcan, and Mustafa Kocagül. "CFD Investigation of Labyrinth Seal Leakage Performance Depending on Mushroom Shaped Tooth Wear." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43607.
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Conventional labyrinth seal applications in turbomachinery encounter a permanent teeth tip damage and wear during transitional operations. This is the dominant issue that causes unpredictable seal leakage performance degradation. Since the gap between the rotor and the stator changes depending on engine transitional operations, labyrinth teeth located on the rotor/stator wear against the stator/rotor. This wear is observed mostly in the form of the labyrinth teeth becoming a mushroom shape. It is known that as a result of this tooth tip wear, leakage performance permanently decreases, which negatively affects the engine’s overall efficiency. However, very limited information about leakage performance degradation caused by mushroom wear is available in open literature. This paper presents a study that numerically quantifies leakage values for various radii of mushroom shaped labyrinth teeth by changing tooth-surface clearance, pressure ratio, number of teeth, and rotor speed. Analyzed parameters and their ranges are mushroom radius (R=0–0.508mm), clearance (cr=0.254–2.032mm), pressure ratio (Rp=1.5–3.5), number of teeth (nt=1–12), and rotor speed (n=0–80krpm). CFD analyses were carried out by employing compressible turbulent flow in 2-D axi-symmetrical coordinate system. CFD leakage results were also compared with well-known labyrinth seal semi-empirical correlations. Given a constant clearance, leakage increases with the size of the mushroom radius that forms on the tooth. This behavior is caused by less flow separation and flow disturbance and the vena contracta effect for flow over the smoothly shaped mushroom tooth tip compared to the sharp-edged tooth tip. This leakage increase is higher when the tooth tip wear is considered as an addition to the unworn physical clearance, since the clearance dominates the leakage. The leakage affected by the number of teeth was also quantified with respect to the mushroom radius. The rotational effect was also studied as a secondary parameter.
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Ohtake, Hiroyasu, Hideyasu Ohtaki, Masato Hagiwara, and Yasuo Koizumi. "Experimental and Analytical Studies on Frictional Pressure Drops of Gas-Liquid Two-Phase Flow in Mini-Micro Pipes and at Vena Contract and Expansion." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-44006.
Full textAbstract:
The frictional pressure drops of gas-liquid two-phase flow in mini-micro pipes and at vena contract and expansion were investigated experimentally and analytically. Pressure drops of straight pipe, sudden enlargement and sudden contraction of gas-liquid two-phase flow in mini-pipes were measured. Test liquid was water at room temperature; test gas was argon. The diameter of the test mini-pipe was 0.5, 0.25 and 0.12 mm, respectively; the length was 500, 250 and 50 mm, respectively. The cross-sectional ratio of the contraction was about 1000; the ratio of the enlargement was about 0.001. The pressure drop data and the flow pattern were collected over 3.0 < UG < 130 m/s for the superficial gas velocity and 0.02 < UL < 6.0 m/s for the superficial liquid velocity. The two-phase friction multiplier data for D > 0.5 mm showed to be in good agreement with the conventional correlations. On the other hand, the two-phase friction multiplier data for D < 0.25 mm differed from the calculated values by the conventional correlations. Then, thickness of liquid film around a gas plug and size of gas core were estimated and the effect of frictional pressure drop on channel size was discussed through Knudsen Number of gas and instability on liquid-gas interface. Namely, the effect of mini-pipe was rarefaction effects, Kn<0.1. New correlation of frictional pressure drop of gas-liquid two-phase flow is proposed for mini pipes. The coefficients of sudden enlargement and sudden contraction in mini-pipes for the gas-water two-phase flow were modified from the present experimental results. The experimental results were also examined through numerical simulation by a commercial code.
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Dogu, Yahya, Mustafa C. Sertçakan, Koray Gezer, Mustafa Kocagül, Ercan Arıcan, and Murat S. Ozmusul. "Leakage Degradation of Straight Labyrinth Seal due to Wear of Round Tooth Tip and Acute Trapezoidal Rub-Groove." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57928.
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In this paper, labyrinth seal leakage is numerically quantified for an acute trapezoidal rub-groove accompanied with a rounded tooth, as a function of rub-groove sizes and tooth-groove axial positions. Analyses parameters include clearance, pressure ratio, number of teeth, and rotor speed. Labyrinth seals wear during engine transients. Radial incursion and axial movement of the rotor-stator pair cause the labyrinth teeth to rub against the unworn stator surface. The labyrinth teeth and/or stator wear depending on their material hardness. Wear damage in the form of material loss or deformation permanently increases seal clearance, and thus, leakage. This leakage is known to be dependent on the shape and geometry of the worn tooth and the stator rub groove. There are two types of reported tooth tip wear. These can be approximated as a mushroom shape and a round shape. The stator rub-groove shapes can be approximately simulated in five forms: rectangle, trapezoid (isosceles and acute), triangle, and ellipse. In this paper, the acute trapezoidal rub-groove shape is specifically chosen, since it is the most similar to the most commonly observed rub-groove form. The tooth tip is considered to be rounded, because the tooth tip wears smoothly and a round shape forms during rub-groove formation. To compare the unworn tooth, the flat stator is also analyzed as a reference case. All analyzed parameters for geometric dimensions (groove width, depth, wall angle, tooth-groove axial position,) and operating conditions (flow direction, clearance, pressure ratio, number of teeth, rotor speed) are analyzed in their practical ranges. CFD analyses are carried out by employing a compressible turbulent flow solver in a 2-D axi-symmetrical coordinate system. CFD analyses show that the rounded tooth leaks more than an unworn sharp-edged tooth, due to the formation of a smooth and streamlined flow around the rounded geometry. This smooth flow yields less flow separation, flow disturbance, and less of vena contract a effect. The geometric dimensions of the acute trapezoidal rub-groove (width, depth, wall angle) significantly affect leakage. The effects of clearance, pressure ratio, number of teeth, and rotor speed on the leakage are also quantified. Analyses results are separately evaluated for each parameter.