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hydraulic

Basics of Fluid Mechanics.pdf

November 16, 2009 · Filed Under Mechanical & Industrial Engineering · Comment  · Tags: ,

Taken from: What is Fluid Mechanics?: The fluid mechanics study involve many fields that have no clear boundary between them. Researchers distinguish between orderly flow and chaotic flow as the laminar flow and the turbulent flow. The fluid mechanics can also be distinguish between a single phase flow and multiphase flow (flow made more than one phase or single distinguishable material). The last boundary (as all the boundaries in fluid mechanics) isn’t sharp because fluid can go through a phase change (condensation or evaporation) in the middle or during the flow and switch from a single phase flow to a multi phase flow. Moreover, flow with two phases (or materials) can be treated as a single phase (for example, air with dust particle).

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Automating Manufacturing Systems with PLCs.pdf

November 9, 2009 · Filed Under Mechanical & Industrial Engineering · Comment  · Tags: , , ,

Taken from PROGRAMMABLE LOGIC CONTROLLERS’s Introduction: Control engineering has evolved over time. In the past humans were the main method for controlling a system. More recently electricity has been used for control and early electrical control was based on relays. These relays allow power to be switched on and off without a mechanical switch. It is common to use relays to make simple logical control decisions. The development of low cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC). The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing controls.
PLCs have been gaining popularity on the factory floor and will probably remain predominant for some time to come. Most of this is because of the advantages they offer: Cost effective for controlling complex systems.
Flexible and can be reapplied to control other systems quickly and easily.
Computational abilities allow more sophisticated control.
Trouble shooting aids make programming easier and reduce downtime.
Reliable components make these likely to operate for years before failure.

Fundamentals of Die Casting Design.pdf

November 7, 2009 · Filed Under Mechanical & Industrial Engineering · Comment  · Tags: , , , ,

Taken from Abstract: Die-casting engineers have to compete not only with other die-casting companies, but also against other industries such as plastics, and composite materials. Clearly, the ”black art” approach, which has been an inseparable part of the engineer’s tools, is in need of being replaced by a scientific approach. Excuses that “science has not and never will work” need to be replaced with “science does work”. All technologies developed in recent years are described in a clear, simple manner in this book. All the errors of the old models and the violations of physical laws are shown. For example, the “common” pQ2 diagram violates many physical laws, such as the first and second laws of thermodynamics. Furthermore, the “common” pQ2 diagram produces trends that are the opposite of reality, which are described in this book.
The die casting engineer’s job is to produce maximum profits for the company.
In order to achieve this aim, the engineer must design high quality products at a minimum cost. Thus, understanding the economics of the die casting design and process are essential. These are described in mathematical form for the first time in this volume. Many new concepts and ideas are also introduced. For instance, how to minimize the scrap/cost due to the runner system, and what size of die casting machine is appropriate for a specific project.
The die-casting industry is undergoing a revolution, and this book is part of it. One reason (if one reason can describe the situation) companies such as Doehler Jorvis (the biggest die caster in the world) and Shelby are going bankrupt is that they do not know how to calculate and reduce their production costs. It is my hope that die-casters will turn such situations around by using the technologies presented in this book. I believe this is the only way to keep the die casting professionals and the industry itself, from being “left in the dust.”

Hydrodinamics of Pumps.pdf

October 22, 2009 · Filed Under Mechanical & Industrial Engineering · Comment  · Tags: , , , , ,

Taken from Abstract: The subject of this monograph is the fluid dynamics of liquid turbomachines, particularly pumps. Rather than attempt a general treatise on turbomachines, we shall focus attention on those special problems and design issues associated with the flow of liquid through a rotating machine. There are two characteristics of a liquid that lead to these special problems, and cause a significantly different set of concerns than would occur in, say, a gas turbine. These are the potential for cavitation and the high density of liquids that enhances the possibility of damaging unsteady flows and forces.

Best Practices for Sustainable Development of Micro Hydro Power in Developing Countries.pdf

September 1, 2009 · Filed Under Civil & Architectural Engineering · Comment  · Tags: , , , , ,

Taken from Introduction: Micro hydro, defined as a plant between 10 kW and 200 kW, is perhaps the most mature of the modern small-scale decentralised energy supply technologies used in developing countries. There are thought to be tens of thousands of plants in the ‘micro’ range operating successfully in China 2, and significant numbers are operated in wide ranging countries such as Nepal, Sri Lanka, Pakistan, Vietnam and Peru. This experience shows that in certain circumstances micro hydro can be profitable in financial terms, while at others, unprofitable plants can exhibit such strong positive impacts on the lives of poor people and the environment that they may well justify subsidies.

The evidence from this extensive experience shows such wide variation in terms of cost, profitability and impact, that it has often been difficult for investors and rural people to determine whether, and under what circumstances, this technology is viable and best meets their needs.

Whilst supplying improved energy services to people for the first time is difficult, supplying such services profitably to very poor people who live far away from roads and the electricity grid poses a particularly difficult challenge. This report shows that micro hydro compares well with other energy supply technologies in these difficult markets. Despite this micro hydro appears to have been relatively neglected by donors, the private sector and governments in the allocation of resources and attention. In the past, rural electrification by means of grid extension was the option favoured by donors. More recently the fashion has switched towards photovoltaics, probably because of its higher foreign content, and the higher added value returned to the metropolitan countries.

The relative neglect of micro hydro has also been in part due to the fact that the circumstances under which it is financially profitable have not been systematically established, at least not in ways that investors find credible. In addition, while it is known that the growth and sustainability of the micro hydro sub-sector depends on certain types of infrastructure and institutional investments, it was often not clear which elements ofthis ‘enabling environment’ were essential, nor how they were best financed.




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