13 resultados para STEAM
em Deakin Research Online - Australia
Resumo:
Wool fiber was modified by steam explosion in this study. SEM results show that some scales on the fiber surface were cleaved and tiny grooves generated during the explosion. FTIR results suggest no evident changes in the chemical composition of the fiber after the explosion treatment. However, the crystallinity of the fiber decreased slightly as the steam pressure increased based on the X-ray results. In the thermal analysis, DSC results show that the temperature corresponding to vaporization of absorbed water and cleavage of disulfide bonds respectively decreased as the steam pressure increased. The reduction in thermal decomposition energy of the treated fiber indicates that steam explosion might have destroyed some crystals and crosslinks of macromolecular chains in the fiber. The treatment also led to some alterations of the fiber properties, including reduction in strength, moisture regain and solubility in caustic solution.
Resumo:
This paper examines the use of pressurized steam for wrapping and setting the yarn hairs concurrently via a new steam-jet process during winding. Yarn torque can also be stabilized as an added advantage. The results obtained with two batches of pure wool yarns suggest that there is potential to achieve yarn hairiness reduction of up to 60 % with minimum deterioration in hairiness even after subsequent rewinding.
Resumo:
Steam-valving and excitation systems play an important role to maintain the transient stability of power systems with synchronous generators when power systems are subjected to large disturbances and sudden load changes. This paper presents a nonlinear adaptive backstepping approach for controlling excitation and steam-valving systems of synchronous generators. In this paper, the proposed excitation and steam-valving controllers are designed in a coordinated manner so that they can work under several and most severe operating conditions. Both excitation and steam-valving controllers are designed by considering some critical parameters as unknown. The effectiveness of the proposed coordinated control scheme is evaluated on a single machine infinite bus system under different operating conditions such as load changes and three-phase short circuit faults at the generator terminal. Finally, performance of the proposed scheme is compared to that of a similar nonlinear adaptive backstepping excitation controller without any coordination and simulation results demonstrate the superiority of the proposed one.
Resumo:
Although the thermodynamic advantages of using solar energy to replace the bleed off steam in the regeneration system of Rankine cycle coal fired power stations has been proven theoretically, the practical techno/economic feasibility of the concept has yet to be confirmed relative to real power station applications. To investigate this concept further, a computer modelling software “THERMSOLV” was developed by Deakin University researchers, together with the support of the Victorian power industry and Australian Research Council (ARC). This newly developed software simulates the steam cycle to assess the techno/economic merit of the solar aided concept for various power station structures, locations and local electricity market conditions. Two case studies, one in Victoria Australia and one in Yunnan Province, China, have been carried out to show the application of the software. This paper reports the structure and functions of the software, and the results of the two case studies.
Resumo:
Although the thermodynamic advantages of using solar energy to replace the bled off steam in the regeneration system of Rankine cycle coal fired power stations has been proven theoretically, the practical techno/economic feasibility of the concept has yet to be confirmed relative to real power station applications. To investigate this concept further, computer modelling software “THERMSOLV” was specifically developed for this project at Deakin University, together with the support of the Victorian power industry and Australian Research Council (ARC). This newly developed software simulates the steam cycle to assess the techno/economic merit of the solar aided concept for various power station structures, locations and local electricity market conditions. Two case studies, one in Victoria Australia and one in Yunnan Province, China, have been carried out with the software. Chapter one of this thesis defines the aims and scope of this study. Chapter two details the literature search in the related areas for this study. The thermodynamic concept of solar aid power generation technology has been described in chapter three. In addition, thermodynamic analysis i.e. exergy/availability has been described in this chapter. The “Thermosolv” software developed in this study is detailed in chapter four with its structure, functions and operation manual included. In chapter five the outcomes of two case studies using the “Thermosolv” software are presented, with discussions and conclusions about the study in chapters 6 and 7 respectfully. The relevant recommendations are then made in chapter eight.
Resumo:
The study is focused on an analysis of the major diplomatic documents from the mid eighteenth century to the present as regards Sri Lanka, or Ceylon as it was known till 1972. The objectives of the study are to identify the issues underlying these diplomatic documents. These include the political and strategic factors and other subsidiary issues like trade and commerce relevant at the time these treaties, agreements, and proposed treaties were formulated. It is also a geopolitical study as it relates to Sri Lanka's geographical position in the Indian Ocean, and her possession of the Trincomalee Harbour on its east coast, which is one of the great natural harbours of the world. Over the centuries this harbour has had significant strategic value for naval deployments. The case study of the eighteenth and nineteenth centuries studies the diplomatic documents against the political and strategic background for the French Revolution and actions of Napoleon, and the Anglo/French rivalry, spreading from Europe to North America and Asia. In the twentieth century the environment for studying the place of Sri Lanka in the Indian Ocean was created by the Russian Revolution, the failure to keep the peace of Versailles after World War I, the conflict and horrors of World War II which led to the disintegration of European colonial empires in Asia and Africa, and the tensions generated by the Cold War. A study of the documents would reveal that in international relations what matters is the ability of a party to promote its interests, and this depends on its power. This realist approach contrasts to the idealist approach where policies are based on moral and ethical principles. For the realist the states should follow to protect their interests and to survive. To achieve this is to strive for a ‘balance of power’. To do so is to form a favourable alliance system. As the documents examined cover a period from the mid-eighteenth century to the later part of the twentieth century, they reflect the changing technologies that have had an influence on naval and military matters. For example, this period witnessed great changes in technology of energy utilized to propel warships, from wind, to steam, to fuel and finally to nuclear power. These changes had an influence in determining strategic policies involving weapon systems and communications within a global and regional setting. The period covered was the beginning of the process described a ‘globalisation’. Its idea is not unique to this century; there were many attempts, in various times of history, to integrate societies within a global context. Viewed in this light, the Anglo-French rivalry of the eighteenth and nineteenth centuries was the indication of a global naval strategy, in which Sri Lanka was a major factor in the Indian Ocean region. This process was associated with the phenomena called the ‘expansion of Europe’. It covered all the oceans of the world and in the nineteenth and twentieth centuries led to the founding of the largest maritime empire the world has ever seen: The British Empire. After World War I, the British naval strength (the basis of the British Empire) and her consequent position as a great power, was challenged by other powers like the United States of America and Japan. After World War II, the US Navy was supreme: and there was a close alliance between Britain and the USA. The strength of the US/British alliance was based on the navy and its bases, which were spread throughout the globe; to project power, and act as deterrence and balancing force. Sri Lanka, due to her strategic position, was a part of this evolving process, and was tied to a global strategy (with its regional connotations) from the eighteenth century to the present.
Resumo:
Solar-aided power generation (SAPG) is capable of integrating solar thermal energy into a conventional thermal power plant, at multi-points and multi-levels, to replace parts of steam extractions in the regenerative Rankine cycle. The integration assists the power plant to reduce coal (gas) consumption and pollution emission or to increase power output. The overall efficiencies of the SAPG plants with different solar replacements of extraction steam have been studied in this paper. The results indicate that the solar thermal to electricity conversion efficiencies of the SAPG system are higher than those of a solar-alone power plant with the same temperature level of solar input. The efficiency with solar input at 330 °C can be as high as 45% theoretically in a SAPG plant. Even the low-temperature solar heat at about 85 °C can be used in the SAPG system to heat the lower temperature feedwater, and the solar to electricity efficiency is nearly 10%. However, the low-temperature heat resource is very hard to be used for power generation in other types of solar power plants. Therefore, the SAPG plant is one of the most efficient ways for solar thermal power generation.
Resumo:
Water shortage is a major problem facing the power industry in many nations around the world. The largest consumer of water in most power plants is the wet cooling tower. To assist water and energy saving for thermal power stations using conventional evaporative wet cooling towers, a hybrid cooling system is proposed in this paper. The hybrid cooling system may consists of all or some of an air pre-cooler, heat pump, heat exchangers, and adsorption chillers together with the existing cooling tower. The hybrid cooling system described in the paper, consisting of a metal hydride heat pump operating in conjunction with the existing wet cooling tower, is capable of achieving water saving by reducing the temperature of warm water entering the cooling tower. Cooler inlet water temperatures effectively reduce the cooling load on existing towers. This will ultimately reduce the amount of water lost to the air by evaporation whilst still achieving the same cooling output. At the same time, the low grade waste energy upgraded by the metal hydride heat pump, in the process of cooling the water, can be used to replace the bleed of steam for the lower stage feed heaters which will increase overall cycle efficiency.
Resumo:
Force measurements between silica surfaces in aqueous solutions of NaCl are reported. Silica is prepared with one of three surface treatments: (i) flaming, (ii) exposure to steam for 150 h, and (iii) brief exposure to ammonia vapor. Analysis of electrical double-layer interactions indicates that the surface density of silanol groups increases with steam treatment, and that exposure to ammonia etches the surface slightly and renders it porous. The force at short range is dominated by a strong repulsion which is attributed to hydration of the surface. The hydration component of the force is not significantly affected by the surface treatments, nor by electrolyte concentration over the range investigated (up to 0.1 M).
Resumo:
An iconic staple of the First-Person Shooter genre, Team Fortress 2 , is popular for its chaotic action, distinguished by its painterly aesthetics, and made unique by the introduction of hats as rewards for its players. This study investigates the intersection of virtual millinery items, player achievements, user generated content and the implications for online gamer personas as they are connected to the digital distribution platform, Steam. The article examines the iterations of affect involved in the design and play of a game no longer imagined by its publisher, the Valve Corporation, as a distinct commodity but rather a commercial community service.
Resumo:
A short composition featuring an Indian bansuri flute, percussion and a soft synth pad.