Crack Cocaine

 Crack  cocaine PDF
Author: United States. Congress. Senate. Committee on Governmental Affairs. Permanent Subcommittee on Investigations
Publisher:
ISBN:
Size: 60.31 MB
Format: PDF
Category :
Languages : en
Pages :
View: 3096

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Book Description:

Three Dimensional Gear Crack Propagation Studies

Three Dimensional Gear Crack Propagation Studies PDF
Author:
Publisher:
ISBN:
Size: 26.98 MB
Format: PDF, Kindle
Category :
Languages : en
Pages : 15
View: 2001

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Book Description: Three-dimensional crack growth simulation was performed on a split-tooth gear design using boundary element modeling and linear elastic fracture mechanics. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth simulation was performed on a case study to evaluate crack propagation paths. Tooth fracture was predicted from the crack growth simulation for an initial crack in the tooth fillet region. Tooth loads on the uncracked mesh of the split-tooth design were up to five times greater than those on the cracked mesh if equal deflections of the cracked and uncracked teeth were considered. Predicted crack shapes as well as crack propagation life are presented based on calculated stress intensity factors, mixed-mode crack propagation trajectory theories, and fatigue crack growth theories.

Gear Crack Propagation Path Studies Guidelines For Ultra Safe Design

Gear Crack Propagation Path Studies  Guidelines for Ultra Safe Design PDF
Author:
Publisher:
ISBN:
Size: 43.58 MB
Format: PDF, ePub, Mobi
Category :
Languages : en
Pages : 16
View: 5299

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Book Description: Design guidelines have been established to prevent catastrophic rim fracture failure modes when considering gear tooth bending fatigue. Analysis was performed using the finite element method with principles of linear elastic fracture mechanics. Crack propagation paths were predicted for a variety of gear tooth and rim configurations. The effects of rim and web thicknesses, initial crack locations, and gear tooth geometry factors such as diametral pitch, number of teeth, pitch radius, and tooth pressure angle were considered. Design maps of tooth/rim fracture modes including effects of gear geometry, applied load, crack size, and material properties were developed. The occurrence of rim fractures significantly increased as the backup ratio (rim thickness divided by tooth height) decreased. The occurrence of rim fractures also increased as the initial crack location was moved down the root of the tooth. Increased rim and web compliance increased the occurrence of rim fractures. For gears with constant pitch radii, coarser-pitch teeth increased the occurrence of tooth fractures over rim fractures. Also, 250 pressure angle teeth had an increased occurrence of tooth fractures over rim fractures when compared to 200 pressure angle teeth. For gears with constant number of teeth or gears with constant diametral pitch, varying size had little or no effect on crack propagation paths.

Gas Initiated Crack Propagation In A Porous Solid

Gas initiated Crack Propagation in a Porous Solid PDF
Author: John Herbert Pitts
Publisher:
ISBN:
Size: 44.14 MB
Format: PDF
Category : Underground nuclear explosions
Languages : en
Pages : 135
View: 5810

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Book Description:

Accelerated Crack Propagation Of Titanium By Methanol Halogenated Hydrocarbons And Other Solutions

Accelerated Crack Propagation of Titanium by Methanol  Halogenated Hydrocarbons  and Other Solutions PDF
Author:
Publisher:
ISBN:
Size: 61.46 MB
Format: PDF, Kindle
Category : Titanium
Languages : en
Pages : 58
View: 6312

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Book Description:

The Crack Club Being Papers Illustrative Of The Temperance Question First And Second Series No 1 35

The Crack Club  Being Papers Illustrative of the Temperance Question     First and Second Series  No  1 35 PDF
Author: John COLLINSON (Perpetual Curate of Lamesley, Durham.)
Publisher:
ISBN:
Size: 27.82 MB
Format: PDF, Mobi
Category :
Languages : en
Pages :
View: 1502

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Book Description:

Crack Spacing And Crack Widths Due To Normal Force Or Bending Moment

Crack Spacing and Crack Widths Due to Normal Force Or Bending Moment PDF
Author: Åke Holmberg
Publisher:
ISBN:
Size: 70.25 MB
Format: PDF, Kindle
Category : Bending moment
Languages : en
Pages : 57
View: 165

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Book Description:

Crack In America

Crack In America PDF
Author: Craig Reinarman
Publisher: Univ of California Press
ISBN: 9780520202429
Size: 74.69 MB
Format: PDF, Docs
Category : Social Science
Languages : en
Pages : 388
View: 5432

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Book Description: A team of veteran drug researchers in medicine, law, and the social sciences provides the most comprehensive, penetrating, and original analysis of the crack cocaine problem in America to date. Helps readers understand why the United States has the most repressive, expensive, yet least effective drug policy in the Western world.

The Emergence Of Crack Cocaine Abuse

The Emergence of Crack Cocaine Abuse PDF
Author: Edith Fairman Cooper
Publisher: Nova Publishers
ISBN: 9781590335123
Size: 58.43 MB
Format: PDF, ePub, Mobi
Category : Social Science
Languages : en
Pages : 106
View: 4107

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Book Description: Cocaine was once considered the elite's drug, with a price so high that only the very wealthy could afford it, and thought by many to be 'safe'. But during the 1980s, a dangerous and cheap derivative began appearing on the street. This drug, crack, is a cocaine free-base produced relatively safely and easily. Because of its low production costs, crack became popular among the lower classes, leading to an epidemic in the late 1980s, with estimates that over one million people used crack cocaine. The drug's name became synonymous with gangs, crime, and violence. Because of the intensity and apparent suddenness of the crack crisis, people began to wonder if there were any warning signs public officials missed and how exactly crack spread across the nation. Some even floated the theory that agencies like the CIA and FBI encouraged the use of crack in inner cities. No matter where it came from, crack is a menace that, though no longer 'epidemic', must be combated along with all other illegal drugs. This book makes a close examination of the development, responses to, and effect of the crack cocaine crisis in the United States. Included are descriptions of cocaine, crack, and the free-basing process. Also examined are the health questions surrounding the abuse problems and the allegations that governmental authorities had advance knowledge of crack. With the war on drugs a perpetual and critical battle in America, the facts and analyses presented here are of paramount importance to the understanding of a major issue of society's safety.

Crack Analysis In Structural Concrete

Crack Analysis in Structural Concrete PDF
Author: Zihai Shi
Publisher: Butterworth-Heinemann
ISBN: 9780080942223
Size: 26.83 MB
Format: PDF, Mobi
Category : Technology & Engineering
Languages : en
Pages : 344
View: 1946

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Book Description: This new book on the fracture mechanics of concrete focuses on the latest developments in computational theories, and how to apply those theories to solve real engineering problems. Zihai Shi uses his extensive research experience to present detailed examination of multiple-crack analysis and mixed-mode fracture. Compared with other mature engineering disciplines, fracture mechanics of concrete is still a developing field with extensive new research and development. In recent years many different models and applications have been proposed for crack analysis; the author assesses these in turn, identifying their limitations and offering a detailed treatment of those which have been proved to be robust by comprehensive use. After introducing stress singularity in numerical modelling and some basic modelling techniques, the Extended Fictitious Crack Model (EFCM) for multiple-crack analysis is explained with numerical application examples. This theoretical model is then applied to study two important issues in fracture mechanics - crack interaction and localization, and fracture modes and maximum loads. The EFCM is then reformulated to include the shear transfer mechanism on crack surfaces and the method is used to study experimental problems. With a carefully balanced mixture of theory, experiment and application, Crack Analysis in Structural Concrete is an important contribution to this fast-developing field of structural analysis in concrete. Latest theoretical models analysed and tested Detailed assessment of multiple crack analysis and multi-mode fractures Applications designed for solving real-life engineering problems