Mechanical Engineering Ebooks

Ebook Some high temperature oxidation characteristics of nickel with chromium additions

Submitted by antoq on Fri, 12/12/2008 - 01:20

The relationship between alloy chromium content and oxidation rate has been determined for nickel-chromium alloys containing up to 17At% chromium. The tests were conducted at 1096C, under one atmosphere of oxygen. The observed structural and phase changes in the oxide were related to the oxidation rate. It has been found that increasing amounts of chromium in the NiO phase govern the oxidation rate for alloys containing less than 2At% chromium. For alloys of greater than 2At% chromium, a complex exchange of chromium among three phases--NiO, Cr2O3 and the spinel, NiCr2O4--has been detected. This chromium exchange was reflected in the lattice parameter of the NiO phase, and in the rate of increase of oxidation rate with chromium addition to the alloy. The present work indicates that an interstitial diffusion mechanism may become dominant in the oxides of high chromium content. Within the scope of the present work, the high oxidation stability of nickel-chromium alloys has been correlated with the presence of Cr2O3 in the oxide layer.


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Ebook Variational integrators

Submitted by antoq on Sat, 12/06/2008 - 07:46

Variational integrators are a class of discretizations for mechanical systems which are derived by discretizing Hamilton's principle of stationary action. They are applicable to both ordinary and partial differential equations, and to both conservative and forced problems. In the absence of forcing they conserve (multi-)symplectic structures, momenta arising from symmetries, and energy up to a bounded error.


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Ebook Interaction law for a collision between two solid particles in a viscous liquid

Submitted by antoq on Sat, 12/06/2008 - 00:00

This thesis addresses the problem of inter-particle collisions in a viscous liquid. Experimental measurements were made on normal and oblique collisions between identical and dissimilar pairs of solid spheres. The experimental evidence supports the hypothesis that the normal and the tangential component of motions are decoupled during a rapid collision.


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Free Ebook Collisional mechanics in solid-liquid flows

Submitted by antoq on Thu, 12/04/2008 - 00:44

Experimental measurements of the particle pressure were obtained for a liquid fluidized bed and for a vertical gravity driven liquid-solid flow. The particle, or granular, pressure is defined as the extra pressure generated by the action of particles in a particulate multi-phase flow. Using a high-frequency-response pressure transducer, individual collisions of particles were collected and measured to obtain a time-averaged particle pressure. Results were obtained for a number of different particles and for two different test section diameters. Results show that the particle pressure experiences a maximum at intermediate concentrations, and that its magnitude is scaled with the particle density and the square of the terminal velocity of the particles. The particle pressure was found to be composed of two main contributions: one from pressure pulses generated by direct collisions of particles against the containing walls (direct component), and a second one from pressure pulses due to collisions between individual particles that are transmitted through the liquid (radiated component).


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Ebook Nox emission control in gas turbines for combined cycle gas turbine plant

Submitted by antoq on Thu, 11/06/2008 - 02:05

The increase, in recent years, in the size and efficiency of gas turbines burning natural gas in combined cycle has occurred against a background of tightening environmental legislation on the emission of nitrogen oxides. The higher turbine entry temperatures required for efficiency improvement tend to increase NOx production. First-generation emission control systems involved water injection and catalytic reduction and were relatively expensive to operate. Dry low-NOx combustion systems have therefore been developed but demand more primary air for combustion. This gives added incentive to the reduction of air requirements for cooling the combustor and turbine blading. This paper reviews the various approaches adopted by the main gas turbine manufacturers which are achieving very low levels of NOx emission from natural gas combustion. Further developments, however, are necessary for liquid fuels.


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Ebook Experiments and analytical investigations of granular materials: shear flow and convective heat transfer

Submitted by antoq on Fri, 10/31/2008 - 02:10

Granular materials flowing down an inclined chute were studied experimentally and analytically. Characteristics of convective heat transfer to granular flows were also investigated experimentally and numerically. Experiments on continuous, steady flows of granular materials in an inclined chute were conducted with the objectives of understanding the characteristics of chute flows and of acquiring information on the rheological behavior of granular material flow. Two neighboring fibre optic displacement probes were employed to measure mean velocity, one component of velocity fluctuations, and linear concentration at the wall and free surface boundaries. A shear gauge was also developed to make direct measurement of shear stress at the chute base. Measurements of solid fraction, velocity, shear rate, and velocity fluctuations were analyzed to understand the chute flow characteristics, and the rheological behavior of granular materials was studied with the present experimental data. The vertical profiles of mean velocity, velocity fluctuation, and solid fraction were also obtained at the sidewalls.


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Free ebook Differential weathering effects and mechanisms

Submitted by antoq on Wed, 10/29/2008 - 01:00

The physical and chemical characteristics of the two differential weathering effects, case hardening and core softening, are examined to determine their formation mechanisms by investigating several field areas exhibiting differential weathering effects. The terms differential weathering effects, factors, mechanisms, processes, morphologies and their cause and effect relationships are defined in the context of the overall problem.


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Free ebook: An experimental and theoretical investigation of two dimensional centrifugal pump impellers

Submitted by antoq on Sun, 10/26/2008 - 02:07

An experimental and theoretical investigation on a series of three centrifugal pump impellers has been made in order to determine the usefulness and validity of tyro-dimensional potential theory for the description of the flow.


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Electrical Engineering ebook : Complexity of information extraction

Submitted by antoq on Sun, 10/26/2008 - 01:18

This thesis describes a mathematical theory that interrelates the basic concepts of complexity, cost, information and reliability. The accessibility of information, as opposed to its availability, is characterized. Universal bounds for complexity distribution, implementation cost and decision reliability are estimated. These bounds give rise to a methodology for any consistent definition of a complexity measure.


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Free E-books The 2007 Powers Fastening Handbook: For anchoring tp All Base Materials

Submitted by acrobat on Thu, 09/18/2008 - 18:52

Free E-books The 2007 Powers Fastening Handbook: For anchoring tp All Base Materials The Powers Fastening Handbook is the latest of many technical publications from Powers Fasteners. The Fastening Handbook is designed as a convenient, quick reference source for the end user. It is small enough to carry just about anywhere: the tool box, job-site trailer, truck, etc..

Although compact, the Handbook contains the entire Powers product line along with useful information including:
• Product Descriptions
• Installation Instructions
• Part Numbers
• Performance Data
• Product Approvals

Content:


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