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A study of trilateral flash cycles for low-grade waste heat recovery-to-power generationAjimotokan, Habeeb A. 10 1900 (has links)
There has been renewed significance for innovative energy conversion
technologies, particularly the heat recovery-to-power technologies for
sustainable power generation from renewable energies and waste heat. This is
due to the increasing concern over high demand for electricity, energy shortage,
global warming and thermal pollution. Among the innovative heat recovery-to-
power technologies, the proposed trilateral flash cycle (TFC) is a promising
option, which presents a great potential for development. Unlike the Rankine
cycles, the TFC starts the working fluid expansion from the saturated liquid
condition rather than the saturated, superheated or supercritical vapour phase,
bypassing the isothermal boiling phase. The challenges associated with the
need to establish system design basis and facilitate system configuration
design-supporting analysis from proof-of-concept towards a market-ready TFC
technology are significant. Thus, there is a great need for research to improve
the understanding of its operation, behaviour and performance. The objective of
this study is to develop and establish simulation tools of the TFCs for improving
the understanding of their operation, physics of performance metrics and to
evaluate novel system configurations for low-grade heat recovery-to-power
generation. This study examined modelling and process simulation of the TFC
engines in order to evaluate their performance metrics, predictions for guiding
system design and parameters estimations. A detailed thermodynamic analysis,
performance optimization and parametric analysis of the cycles were
conducted, and their optimized performance metrics compared. These were
aimed at evaluating the effects of the key parameters on system performances
and to improve the understanding of the performance behaviour. Four distinct
system configurations of the TFC, comprising the simple TFC, TFC with IHE,
reheat TFC and TFC with feed fluid-heating (or regenerative TFC) were
examined. Steady-state steady-flow models of the TFC power plants,
corresponding to their thermodynamic processes were thermodynamically
modelled and implemented using engineering equation solver (ESS). These
models were used to determine the optimum synthesis/ design parameters of the cycles and to evaluate their performance metrics, at the subcritical operating
conditions and design criteria. Thus, they can be valuable tools in the
preliminary prototype system design of the power plants. The results depict that
the thermal efficiencies of the simple TFC, TFC with IHE, reheat TFC and
regenerative TFC employing n-pentane are 11.85 - 21.97%, 12.32 - 23.91%,
11.86 - 22.07% and 12.01 - 22.9% respectively over the cycle high temperature
limit of 393 - 473 K. These suggest that the integration of an IHE, fluid-feed
heating and reheating in optimized design of the TFC engine enhanced the heat
exchange efficiencies and system performances. The effects of varying the
expander inlet pressure at the cycle high temperature and expander isentropic
efficiency on performance metrics of the cycles were significant. They have
assisted in selecting the optimum-operating limits for the maximum performance
metrics. The thermal efficiencies of all the cycles increased as the inlet
pressures increased from 2 - 3 MPa and increased as the expander isentropic
efficiencies increased from 50 - 100%, while their exergy efficiencies increased.
This is due to increased net work outputs that suggest optimal value of pressure
ratios between the expander inlets and their outlets. A comprehensive
evaluation depicted that the TFC with IHE attained the best performance
metrics among the cycles. This is followed by the regenerative TFC whereas
the simple TFC and reheat TFC have the lowest at the same subcritical
operating conditions. The results presented show that the performance metrics
of the cycles depend on the system configuration, and the operating conditions
of the cycles, heat source and heat sink. The results also illustrate how system
configuration design and sizing might be altered for improved performance and
experimental measurements for preliminary prototype development.
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A study of trilateral flash cycles for low-grade waste heat recovery-to-power generationAjimotokan, Habeeb A. January 2014 (has links)
There has been renewed significance for innovative energy conversion technologies, particularly the heat recovery-to-power technologies for sustainable power generation from renewable energies and waste heat. This is due to the increasing concern over high demand for electricity, energy shortage, global warming and thermal pollution. Among the innovative heat recovery-to- power technologies, the proposed trilateral flash cycle (TFC) is a promising option, which presents a great potential for development. Unlike the Rankine cycles, the TFC starts the working fluid expansion from the saturated liquid condition rather than the saturated, superheated or supercritical vapour phase, bypassing the isothermal boiling phase. The challenges associated with the need to establish system design basis and facilitate system configuration design-supporting analysis from proof-of-concept towards a market-ready TFC technology are significant. Thus, there is a great need for research to improve the understanding of its operation, behaviour and performance. The objective of this study is to develop and establish simulation tools of the TFCs for improving the understanding of their operation, physics of performance metrics and to evaluate novel system configurations for low-grade heat recovery-to-power generation. This study examined modelling and process simulation of the TFC engines in order to evaluate their performance metrics, predictions for guiding system design and parameters estimations. A detailed thermodynamic analysis, performance optimization and parametric analysis of the cycles were conducted, and their optimized performance metrics compared. These were aimed at evaluating the effects of the key parameters on system performances and to improve the understanding of the performance behaviour. Four distinct system configurations of the TFC, comprising the simple TFC, TFC with IHE, reheat TFC and TFC with feed fluid-heating (or regenerative TFC) were examined. Steady-state steady-flow models of the TFC power plants, corresponding to their thermodynamic processes were thermodynamically modelled and implemented using engineering equation solver (ESS). These models were used to determine the optimum synthesis/ design parameters of the cycles and to evaluate their performance metrics, at the subcritical operating conditions and design criteria. Thus, they can be valuable tools in the preliminary prototype system design of the power plants. The results depict that the thermal efficiencies of the simple TFC, TFC with IHE, reheat TFC and regenerative TFC employing n-pentane are 11.85 - 21.97%, 12.32 - 23.91%, 11.86 - 22.07% and 12.01 - 22.9% respectively over the cycle high temperature limit of 393 - 473 K. These suggest that the integration of an IHE, fluid-feed heating and reheating in optimized design of the TFC engine enhanced the heat exchange efficiencies and system performances. The effects of varying the expander inlet pressure at the cycle high temperature and expander isentropic efficiency on performance metrics of the cycles were significant. They have assisted in selecting the optimum-operating limits for the maximum performance metrics. The thermal efficiencies of all the cycles increased as the inlet pressures increased from 2 - 3 MPa and increased as the expander isentropic efficiencies increased from 50 - 100%, while their exergy efficiencies increased. This is due to increased net work outputs that suggest optimal value of pressure ratios between the expander inlets and their outlets. A comprehensive evaluation depicted that the TFC with IHE attained the best performance metrics among the cycles. This is followed by the regenerative TFC whereas the simple TFC and reheat TFC have the lowest at the same subcritical operating conditions. The results presented show that the performance metrics of the cycles depend on the system configuration, and the operating conditions of the cycles, heat source and heat sink. The results also illustrate how system configuration design and sizing might be altered for improved performance and experimental measurements for preliminary prototype development.
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Vznikající bezpečnostní trojúhelník v Asijsko-pacifickém regioně? Bezpečnostní vztahy USA, Austrálie a Japonska / Emerging Security Triangle in the Asia-Pacific Region? The United States and Australia-Japan Security RelationsZaťková, Eva January 2009 (has links)
This thesis concerns the development of trilateral strategic partnership between Australia, Japan and the United States and its implications for the security architecture of the Asia-Pacific region. For over half a century, the predominant means for organizing security cooperation in this region has been through the creation and maintenance of bilateral defence arrangements. In response to changing international conditions, including the rise of China and nontraditional security threats, US strategic thinking has begun to look beyond the traditional model of US-led bilateral alliances in the Asia-Pacific. The emerging Australia- Japan-US security cooperation in the form of Trilateral Security Dialogue, established in 2002 and elevated to a ministerial-level Strategic Dialogue in 2005, indicates that the three allies have strengthened their ties and expanded their cooperation to build a more integrated and cohesive trilateral response to joint regional concerns.
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臺灣企業在中國大陸經濟發展中之角色與定位-三邊統治理論之應用 / The role of Taiwaness Enterprises in the Econoical development of Mainland China - A Trilateral Theory Perspective蘇明瑞, Su, Ming Jui Unknown Date (has links)
自從大陸經濟改革開放以來,外商赴大陸投資之熱潮,風起雲湧。以大陸豐沛之資源與取之不盡之勞動力,再加上外商科技與經營管理之整合,在可見之未來,臺灣將無法與之競爭。然而,在外商進軍大陸之際,臺灣企業並非無著力之處,臺灣可以扮演外商與大陸間之中介橋樑,由於外商因語言、風俗、文化與對大陸當地之不了,將會面臨極大之困難,此時臺灣企業恰可扮演一支援之角色,並在中介之過程中,取得未來競爭之能力與地位。而此三邊統治(中介角色)極為本研究所探究之重點。本研究依據文獻之整理,認為外商在赴大陸經營管理之過程中,其所遭遇之困難來自於四方面,即交易雙方之緊密程度、價值活動資產之專屬程度、價值活動之生產特性與廠商價值活動之生產能力。亦依據文獻歸納區分成三種:三邊仲介、網路中介與內部化支援。並依據上述之分類,本研究依據上述之變數加以推論可能之統治模式,並提出本研究之假說,本研究經個案實際訪談與歸納,並與假說加以驗證。
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Stability of Multilateral Haptic Teleoperation SystemsMendez, Victor H Unknown Date
No description available.
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En svensk tiger…jamar? : Den svenska självbilden under Natoprocessen 2022–2023 som exempel på demokratisk propaganda / A Swedish tiger...meows? : The Swedish self-image during the NATO-process 2022–2023 as an example of democratic propagandaSarsour, Amer January 2023 (has links)
The primary purpose of this thesis is to analyze the rhetorical transformations of the Swedish self-image during the NATO process, particularly through the lens of democratic propaganda as described by the French philosopher and sociologist Jacques Ellul. It explores how this image is constructed and communicated in Swedish media, with a specific focus on the public service broadcaster Sveriges Television (SVT). The research methodology employed in this thesis is a thematic-oriented close reading approach. The analysis concentrates on passages that primarily discuss the image of Sweden, examining them within the framework of Jacques Ellul's theory of democratic propaganda. The study explores the characteristics of democratic propaganda, its mechanisms, and manifestations. Of particular interest are aspects related to how democratic propaganda can help the state reinforce collective myths about the ideals of democracy as reflected in the analyzed material. Rather than using a specific rhetorical analysis method such as topic analysis or cluster analysis, the study is guided by the questions motivated by the theory itself.
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