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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avaliação de desempenho energético de um gerador elétrico operando no modo dual, utilizando biogás e blendas de biodiesel de óleo residual de fritura / Energy performance evaluation of an electric generator operating in dual mode using biogas and biodiesel blends of frying residual oil

Colle, Daniel 28 March 2018 (has links)
Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2018-06-26T12:55:51Z No. of bitstreams: 2 Daniel_Colle.pdf: 2328894 bytes, checksum: ebc7123a9d0ac2a49544f8c63f351ad5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-26T12:55:51Z (GMT). No. of bitstreams: 2 Daniel_Colle.pdf: 2328894 bytes, checksum: ebc7123a9d0ac2a49544f8c63f351ad5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-28 / The generation of electric energy through alternative sources of energy has been a theme constantly addressed by the researchers, both for the concern for alternatives to the energy supply and for the search of the reduction of environmental impacts in its generation. This research addresses the generation of electric energy through the use of biogas and biodiesel, both fuels from renewable sources. The performance of an electricity generator operating in dual mode with biogas and biodiesel blends was evaluated. The evaluated biodiesel was obtained from frying residual oil and experiments were performed with blends of pre-established proportions in B8 (commercial diesel - 8% biodiesel), B20 (20% biodiesel), B50 (50% biodiesel), B80 (80% biodiesel) and B100 (pure biodiesel). The biogas used came from biodigestor of swine residues. The motor generator set has a maximum power of 5.0 kVA and an output voltage of 110 and 220 V. In the tests the motor generator set was coupled to a bank of resistive loads, varying from 0 to 100% of the maximum load. Each increment was of 10%, allowing to obtain the power of generation for varied loads. The lower calorific value of biodiesel (B100) was 35912 kJ.kg-1 and biogas was 22562 kJ.m-3. The electric power generated was superior in the dual mode presenting differences of 18.76% for B8 and 21.77% for B100. The specific liquid fuel consumption was lower in the dual mode with 270.17 g.kWh-1 operating with B8 and 285.29 g.kWh-1 operating with B100 compared to the normal mode. The efficiency was higher in the normal mode, presenting results of 22.01% and 24.74%, operating with B8 and B100 respectively, against 17.51% and 20.18% in the dual mode. The average fuel economy for the B8 blend was 30.06% and 30.08% for B100 in dual mode over the normal mode. The results indicate the possibility of the use of biodiesel from frying waste oil in normal mode, as well as its use in dual mode together with biogas. / A geração de energia elétrica por meio de fontes alternativas de energia tem sido um tema constantemente abordado pelos pesquisadores, tanto pela preocupação por alternativas ao fornecimento de energia quanto pela busca da redução de impactos ambientais em sua geração. Esta pesquisa aborda a geração de energia elétrica por meio do uso de biogás e biodiesel, ambos combustíveis oriundos de fontes renováveis. Foi avaliado o desempenho de um gerador de eletricidade operando no modo dual com biogás e blendas de biodiesel. O biodiesel avaliado foi obtido a partir de óleo residual de fritura e foram realizados experimentos com blendas de proporções pré-estabelecidas em B8 (diesel comercial - 8% de biodiesel), B20 (20% de biodiesel), B50 (50% de biodiesel), B80 (80% de biodiesel) e B100 (biodiesel puro). O Biogás utilizado foi oriundo de biodigestor de resíduos de suinocultura. O conjunto motor gerador apresenta potência máxima de 5,0 kVA e tensão de saída 110 e 220 V. Nos ensaios o conjunto motor gerador foi acoplado a um banco de cargas resistivas, com variações de 0 a 100% da carga máxima. Cada incremento foi de 10%, permitindo obter a potência de geração para cargas variadas. O poder calorífico inferior (PCI) do biodiesel (B100) foi de 35912 kJ.kg-1 e do biogás foi de 22562 kJ.m-3. A potência elétrica gerada foi superior no modo dual apresentando diferenças de 18,76% para B8 e 21,77% para B100. O consumo específico de combustível líquido foi menor no modo dual apresentando 270,17 g.kWh-1 operando com B8 e 285,29 g.kWh-1 operando com B100 em relação ao modo normal. A eficiência foi maior no modo normal apresentando resultados de 22,01% e 24,74% operando com B8 e B100 respectivamente, contra 17,51% e 20,18% no modo dual. A média de economia de combustível líquido para a mistura B8 foi de 30,06% e de 30,08% para B100 no modo dual em relação ao modo normal. Os resultados indicam a possibilidade da utilização de biodiesel de óleo residual de fritura no modo normal, assim como sua utilização no modo dual juntamente com o biogás.
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Motor de combustão interna dual operando com diesel, biodiesel e gás natural: análises de desempenho e emissões. / Internal combustion engine dual operating with diesel, biodiesel and natural gas: analysis of performance and emissions.

SILVA, Fernando José da. 14 September 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-14T11:05:38Z No. of bitstreams: 1 FERNANDO JOSÉ DA SILVA - TESE (PPGEP) 2014.pdf: 7661090 bytes, checksum: d6d7296ae6b4537cc796b5ad44bc0b46 (MD5) / Made available in DSpace on 2018-09-14T11:05:38Z (GMT). No. of bitstreams: 1 FERNANDO JOSÉ DA SILVA - TESE (PPGEP) 2014.pdf: 7661090 bytes, checksum: d6d7296ae6b4537cc796b5ad44bc0b46 (MD5) Previous issue date: 2014-02-24 / CNPq / O combustível gasoso (gás natural) tem sido muito utilizado em motores diesel nos últimos anos, devido suas características positivas quando o foco é o nível das emissões lançadas na atmosfera. O biodiesel; combustível renovável, tem se apresentado como potencial alternativo para contribuir com a redução das emissões poluentes no mundo, com propriedades comparáveis ao diesel, tem sido usado amplamente em motores do ciclo diesel. O desafio é utilizar o motor diesel que opere de forma dual (líquido/gás), com misturas adequadas de diesel, biodiesel e gás natural, para obter a proporção correta de cada combustível, mantendo as características originais do motor e bom desempenho. Neste sentido, o objetivo desta pesquisa é analisar o desempenho, as características das emissões de um motor diesel, trabalhando com diesel comercial B5, biodiesel e gás natural. O combustível utilizado no motor consiste na mistura de 15% de óleo diesel e biodiesel (combustível líquido) e 85% de gás natural. Experimentos foram realizados em potências de 40, a 120 kW, com intervalos de 20 kw. O motor foi instrumentado para obter temperatura, fluxos de massa de ar, gás, diesel e biodiesel, pressão do ar de entrada do motor, do óleo lubrificante e concentração dos gases de combustão durante cada teste experimental. O custo específico do motor operando no modo dual foi melhor do que no modo diesel e a mistura diesel, biodiesel e gás natural que apresentou o menor custo específico, foi a mistura B50. Verificou-se a partir dos resultados experimentais que as emissões de NOx, NO e CO2 diminuíram, enquanto que as emissões de CO aumentaram, quando comparadas com a condição do motor operando no modo diesel comercial B5 como único combustível. / The gaseous fuel (Natural Gas) has been widely used on diesel engines in the last few years, due to its positive characteristics as far as the level of emissions released in the atmosphere is concerned. Biodiesel has been considered a potential alternative to contribute to reducing pollutant emissions level in the world, as a renewable fuel, its properties are comparable to the one of the diesel fuel which is already widely used in diesel engines. The big challenge is to use the diesel engine which operates in a dual form, using adequate mixtures of diesel, biodiesel and natural gas to obtain the correct proportion of each fuel and maintaining the original characteristics of the engine as well as a good performance. In this sense, the aim of this research is to study the characteristics of the commercial diesel engine emissions, operating with B40, B50, B60 and natural gas. The fuel used in the engine consists of a mixture of 15% diesel and biodiesel (liquid fuel) and 85% natural gas. Experiments were made using 40, to 120 kW, with an interval of 20 kW. The engine was instrumented to obtain the temperature, air, gas, diesel and biodiesel flow rate, the air pressure at the entrance of the engine, the lubricant oil temperature, and the concentration of exhaust gases during each experimental test. The specific cost of the engine operating in dual mode was better than in diesel mode, and the blend of diesel, biodiesel and natural gas with the lowest specific cost was the B50 blend. It was verified that the emission of NOx, NO and CO2 had decreased while the emissions of CO had increased, when compared to the conditions using commercial diesel (B5) as the only fuel.
3

我國金控公司子公司組合與雙引擎策略對金控績效與風險影響之分析 / The Impact of Subsidiary Combination and Dual-Engine Strategies on Financial Holding Companies’ Performance and Risk

徐士閎, Hsu, Shi Hong Unknown Date (has links)
本文探討我國金控公司在不同子公司組合以及考量雙引擎策略下,對各種績效指標以及風險指標影響。資料取樣我國2002年至2013年間15家金控公司之季度資料,在考量過去關於金融機構及金控公司多角化經營與子公司組合有關文獻後,選取適當控制變數搭配「以銀行搭配壽險為主」之虛擬變數進行分析,並以虛擬變數及三種集中率進行穩健度測試及並觀察不同面向影響;接著於雙引擎分析當中,試圖發展用於測量雙引擎策略程度之兩種平衡率變數,並且考量交叉項的效果,分別加入模型中進行分析分析。研究結果分為複迴歸、追蹤資料模型,以及關於落後一期自變數對當期應變數之延伸分析。   在複迴歸及追蹤資料模型進行橫斷面及縱斷面之實證研究結果指出,金控投入的資源越分散(資產多角化程度越高)或是越集中(集中率越高)皆未能顯著提昇金控績效或降低風險;然而若考慮雙引擎策略時,則能顯著提昇EPS、P/B Ratio或RBC,同時,不論資產面或營收面建立的平衡率變數,皆可觀察出金控旗下兩大子公司在收益傾向越相等的情況下,具顯著改善金控整體獲利能力、投資人評價或是降低破產風險的情況。   本研究對於各個金控公司前一期的自變數對當期應變數進行延伸分析,實證結果支持了本研究對於投入到產出存在時間落差的假設,亦即以資產平衡率而言,較屬於以資源「投入」概念觀察雙引擎策略程度,因此需要隔一段時間才能展現對於績效與風險的影響;而收益平衡率則偏向以當期「產出」的概念觀察雙引擎變數,此時用於衡量下一期之績效指標將會傾向不顯著,但對於風險方面則傾向能夠顯著降低破產風險。 / This study investigates the relationship of different subsidiary combination and dual-engine strategies on financial holding companies’ performance and risk. Using quarterly data for 15financial holding companies(FHCs)in the R.O.C for the period 2002Q1–2013Q4 and controlling for the size, size growth, equity ratio and diversification. In order to analysis the issue, we choose “the top-two subsidiaries are bank and life insurance” as a dummy variables, asset and revenue balance ratio as dual-engine variables. Also, the paper introduces several relevant variables to implement the robust tests. These relevant variables are “the FHC has subsidiary of life insurance”, three concentration ratios and two interaction variables. Our empirical finding can be divided into three parts: multiple regression, panel data and one-period lagged data analysis.   In multiple regression and panel data, we find evidence that both higher diversification and concentration in subsidiary resource have an ambiguities relation for the performance and risk of financial holding companies. However, considering dual-engine strategies can significantly improve the EPS, P/B Ratio and RBC in empirical results. Also, both asset and revenue balance ratios have significant effect to improve the earning power, the valuation of investors and the insolvency risk.   This paper also use the one time lagged data to conduct the extension study. The findings support the assumption of ours that FHCs exist time-lag between input and output. The asset balance ratio is more like the input concept and the revenue balance ratio is rather more like the output concept when we discuss the dual-engine strategies. In other words, there need more time to show the impact of performance and risk indicators when we use the asset balance ratio. However, output variable has insignificant relation to the performance indicators and significant effect to the risk indicator when we use the revenue balance ratio.
4

泛公股金控公司發展雙引擎策略之研究-以M金控(股)公司為例 / A Case Study on Business Development in the form of Dual-Engine Strategies of Government-Invested Financial Holding Company

徐明智, Hsu, Ming Chih Unknown Date (has links)
自從2002年國泰金控合併世華銀行後,創造金控雙引擎模式,該模式無論在資金運用及獲利效率上都有可行之處,引發同業仿效。 國內泛公股金控公司中不乏擁有壽險子公司者,但因規模太小尚未構成雙引擎模式。鑒於國泰、富邦及中信等三家金控雙引擎公司發展成功經驗,使其資產規模及財務績效均名列前矛,反觀泛公股金控單引擎公司相形見拙,若再不改變策略調整結構,恐將喪失競爭優勢及生存空間。 金控雙引擎策略議題之相關資料較少,因此採用個案研究法,藉由文獻回顧探討總體策略及多角化經營相關問題,運用杜邦分析法凸顯金控單引擎與金控雙引擎差異之處,應用交易成本理論提出併購壽險公司策略方案,建議個案公司發展金控雙引擎策略。 本研究發現:個案公司集中資源聚焦本業使稅前純益率較高,但因總資產週轉率及權益乘數較低致稅前ROE不如三家比較公司;個案公司以利息淨收益為主,在低利率環境下應變能力較差,因此財富管理業務尚有補強空間;個案公司沒有壽險子公司,缺乏資產匯集能力與資金投資動能,成長速度相對遲緩;個案公司具國際競爭潛質,轉型發展金控雙引擎策略可強化競爭優勢,避免遭入主。
5

Análise energética e exergética de um motor de combustão interna operando com mistura de diesel e gás natural. / Energetic and exergetic analyses of an internal diesel engine being operated with natural gas and diesel mixture.

COSTA, Yoge Jeronimo Ramos da. 23 April 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-23T16:43:37Z No. of bitstreams: 1 YOGE JERONIMO RAMOS DA COSTA - TESE PPGEP 2007..pdf: 3893859 bytes, checksum: a59d1d9d1668799657fcdaabc841e817 (MD5) / Made available in DSpace on 2018-04-23T16:43:37Z (GMT). No. of bitstreams: 1 YOGE JERONIMO RAMOS DA COSTA - TESE PPGEP 2007..pdf: 3893859 bytes, checksum: a59d1d9d1668799657fcdaabc841e817 (MD5) Previous issue date: 2007-04-02 / A escassez energética e impacto ambiental são fatores determinantes para a existência de novos estudos da conversão e uso de energia, e a redução dos níveis de poluentes na atmosfera. A operação que usa diesel e gás natural é indicada como uma das melhores formas para controlar emissões de poluentes oriundos de motores diesel e simultaneamente economizar diesel derivado de petróleo. Neste sentido, este trabalho tem como objetivos, estudar teórica e experimentalmente as características de emissões e performance de um motor de combustão interna do ciclo Diesel operando com diesel e gás natural. O sistema térmico experimental é composto de um motor de combustão interna acoplado a um gerador elétrico, instrumentado com sensores de temperatura, pressão, medidores de vazão de ar, diesel e gás natural, sondas de gás e sistema de absorção de potência, constituído por um banco de carga e seu sistema de controle. Para análise energética e exergética teórica do motor foi desenvolvido um modelo matemático baseando-se nos conceitos da termodinâmica. Resultados numéricos e experimentais dos efeitos das condições do ar, tipo e quantidade de combustível, e gases de escape sobre o desempenho do motor e impacto ambiental são apresentados e analisados. A utilização de motores do ciclo diesel trabalhando de forma dual é consideravelmente viável do ponto de vista ecológico, visto a redução da emissão de poluentes tais como CO, CO2, NO e SO2. Com relação aos custos operacionais, estes também se apresentam favoráveis, principalmente para valores de potência superiores a 100 kW. / The energetic shortage and environmental impact are main factors to new research in conversion and use of energy. Natural gas and diesel dual-fuel operation is regarded as one of the best way to control pollutant emissions from the diesel engine and simultaneously save petroleum based diesel fuel. In this sense, the aim of this work is to investigate theorical and experimentally the emissions and performance characteristics of a commercial diesel engine being operated with natural gas and diesel. Experimental facilities (thermal system) is composed by a diesel engine complying to electronic generator, and it was equipped with temperature and pressure sensors, gas, air and diesel flowmeters, gas analyzer and power absorption system (electric charge bank and control system). For energetic and exergetic analysis one mathematical model based in the concept of thermodynamics was developed. The predicted and experimental results of the effect of air conditions, type and quantity of fuel, and exhaust gas in the performance of engine and environmental impact are presented and analyzed. The use of engines of the cycle diesel working in dual mode is considerably viable of the ecological point of view, seen the reduction of the emission of pollutant such as CO, CO2 and SO2. Regarding the operational costs, these also are favorable, mainly for superior power values to 100 kW.
6

我國金控公司經營績效與風險之研究-以子公司組合與市佔率為例 / A study on financial holding companies' performance and risk: Evidence from subsidiary combination and market share

陳時年, Chen, Shih Nien Unknown Date (has links)
本研究利用複迴歸模型與追蹤資料模型,透過子公司市佔率探討金控子公司組合,與公司績效及風險之關聯性,期望能找出何種子公司組合,對於金控公司的績效與風險最有影響。依據2002-2015之季資料,本文主要研究結果如下: (一)若以全產業角度而言,壽險業、證券業與票券業市佔率,對於金控績效與風險影響較為顯著。壽險業市佔率增加,會提高金控之系統風險與個別風險,而證券業市佔率增加,會提高金控的總風險、系統風險與個別風險。本研究推測主要原因為壽險業與證券業的產業風險較高,容易影響金控之經營風險,故有此現象。 (二)金控若採用雙引擎策略,可以降低金控之總風險與系統風險,亦即雙引擎策略對金控之風險經營有穩健的效果。 (三)以銀行業與壽險業組合為探討對象時,則發現銀行業市佔率提高,可能使金控之破產風險上升,而壽險業的市佔率提高,金控之總風險與系統風險亦會提升。此結果顯示銀行與壽險業的子公司組合無法有效改善金控之風險因子。 (四)以銀行業與產險業組合為探討對象時,則發現銀行市佔率提升,可能使金控之各項風險因子增加,並且會降低風險調整後的報酬。而產險業市佔率增加,則會降低金控績效,並提高金控之破產風險。 (五)以銀行業與證券業組合為探討對象時,則發現證券業市佔率增加,僅會顯著增加金控之個別風險。 (六)以銀行業與票券業組合為探討對象時,則發現銀行業市佔率增加,可能使金控之績效下降,並提高金控之破產風險,然而若票券業市佔率提高,反而會增加金控之經營績效,並降低破產風險。 / This study analyzes the effect of the subsidiary combination and market share on the performance and risk of financial holding companies (FHCs). Based on the data of 2002Q1-2015Q4, the empirical result can be summarized as follows. 1. From the viewpoint of the whole industry, there is a significant relation between the market share of the subsidiaries and the performance and risk of FHCs. The result shows there is a positive effect of life insurance market share on systematic risk and idiosyncratic risk. And there is a positive effect of securities market share on total risk, systematic risk and idiosyncratic risk. 2. FHCs can reduce their total risk and systematic risk by taking dual-engine strategy. The result shows that dual-engine strategy is a sound strategy for FHCs’ operation. 3. For the subsidiary combination of bank and life insurer, there is a positive relation between bank market share and insolvency risk. And there is a positive relation among life insurance market share, total risk and systematic risk. 4. For the subsidiary combination of bank and property insurer, there is a positive relation among bank market share and FHCs’ risk. And there is a negative relation between property insurance market share and FHCs’ performance. 5. For the subsidiary combination of bank and securities company, there is a positive relation between securities market share and idiosyncratic risk. 6. For the subsidiary combination of bank and bills company, the increase of bank market share is unfavorable for FHCs’ operation, but the increase of bills company is beneficial for FHCs’ operation.

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