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The federal government asserted a role in fighting narcotics abuse since the early 20^th century, but it was not until the Richard Nixon administration starting in 1969 that a federal “war on drugs” became high profile. Nixon stressed drives against smuggling heroin from counties like Turkey and Mexico. His administration's efforts were marred by raids on erroneous locations by a new federal Office of Drug Law Enforcement. A successor agency called the ‘Drug Enforcement Administration’ jockeyed with the FBI for supremacy in the drug enforcement field. Drug treatment generally had lower priority when it came to funding. A scourge of “crack” cocaine spread in the mid‐1980s, causing Congress to increase penalties for drug abuse in such a way that black people who primarily used crack were punished much more severely than whites who tended to use cocaine's powder form. An effort to coordinate federal antidrug resources better resulted in the establishment of a White House director of drug control policy (“drug czar”) in 1989; the first to hold the position was former education secretary William Bennett. Drug abuse declined in the 1990s, but there was disagreement over the primary cause. Advocates credited a combination of more‐intense law enforcement, better treatment, and establishment of more than 500 “drug courts” that could ride herd on offenders. The numbers of drug abusers were creeping back up by 1999.

This chapter considers the three theorized causes of crime declines in increasing order of novelty—first police, then the rise and fall of crack cocaine, and finally the impact of increased access to abortion that, advocates claim, caused a shift in the crime-risk profile of birth cohorts in the 1970s. After an introductory discussion of the definition and special problems of theories that were inspired by the 1990s' decline, unequal attention is given to the three explanations covered. Over half of the chapter addresses the thesis that crime declines in the 1990s were caused by the coming-of-age of population cohorts that were altered by the impact of elective abortion in the United States in the 1970s.

This chapter begins with a discussion of the causes of the roughening and grooving of solid surfaces. It then discusses Asaro-Tiller surface instability, phase field models, surface patterns caused by energetic photons and ions, surface stress during rapid heating, stress corrosion cracking, and numerical methods.

Loaded slit cracks are modelled as continuous distributions of dislocations with infinitesimal Burgers vectors. Cauchy-type singular integral equations for the density of Burgers vector in these distributions are solved using the theory of Chebyshev polynomials. The elastic fields of mode I elastic slit cracks are derived and the stress intensity factor is defined. Other defects may interact with cracks such as dislocations. This leads to the concepts of shielding and anti-shielding of cracks by dislocations. The Dugdale–Bilby–Cottrell–Swinden model of a mode I crack completely shielded by a plastic zone is derived. By introducing a dislocation free zone between the plastic zone and the crack tip the crack tip is only partially shielded, enabling more brittle tendencies to be described. Griffith’s energy criterion for the growth of an existing crack is seen as necessary but not sufficient. The Barenblatt crack introduces the influence of interatomic forces at the crack tip.

Ice is a material that exhibits both ductile flow, as in the flow of a glacier, and also brittle fracture, as in the crushing of ice under impact from an icebreaker. This chapter considers laboratory-scale experiments on the deformation of single crystals and of polycrystalline ice and their interpretation. Creep of single crystals occurs by the glide and multiplication of dislocations on the basal plane and is thus highly anisotropic. In polycrystalline specimens deformed under constant load the creep accelerates, reaches a steady state and finally accelerates again. The deformation of individual grains is confined by those around them, and large stresses build up which may be relieved by diffusion or by cracking. The theory of fracture involves both the nucleation of cracks and their propagation.

Surface cracks and boundaries give contrast in acoustic microscopy even when they are so fine that by conventional resolution criteria they would be expected to be scarcely visible. The contrast arises from the scattering of Rayleigh waves, and the evidence for this is the tell‐tale presence of fringes parallel to cracks, with spacing equal to half a Rayleigh wavelength. Contrast theory based on separating the specular and Rayleigh components of the signal give a good account of the fringes which are observed. Time‐resolved measurements can be made of crack‐tip diffracted signals. The remarkable contrast from cracks is useful in the study of indentation and fracture of low‐ductility materials.

This book is about recent mathematical, numerical and statistical approaches for elasticity imaging of inclusions and cracks with waves at zero, single or multiple non-zero frequencies. It considers important developments in asymptotic imaging, stochastic modeling, and analysis of both deterministic and stochastic elastic wave propagation phenomena and puts them together in a coherent way. It gives emphasis on deriving the best possible imaging functionals for small inclusions and cracks in the sense of stability and resolution. For imaging extended elastic inclusions, the book develops accurate optimal control methodologies and examines the effect of uncertainties of the geometric or physical parameters on their stability and resolution properties. It also presents an asymptotic framework for vibration testing and a method for identifying, locating, and estimating inclusions and cracks in elastic structures by measuring their modal characteristics.

This chapter examines rap's unique expressive position in relation to the primary contradictions of crack cocaine's punishment structure as well as recent arguments condemning this structure, including those from the U.S. Supreme Court and the U.S. Sentencing Commission. After discussing the contradictory policy contexts out of which crack's lethal logic of work eventually emerged, the chapter considers the “punitive turn” in U.S. crime-control policy and the “scholarly near misses” that have influenced analyses of the rap–crack connection. It suggests ways of rethinking the rap–crack connection in order to move beyond reductionist accounts in which rap and inner-city communities are taken as mere reflections of each other.

This chapter examines the cultural resonance between rap and crack cocaine by focusing on the complicated sociolegal logics that paved the way for the drug's lethal effects, and out of which its symbolic power developed. It first considers the law and policy on crack, including the bill signed by President Barack Obama in August 2010 repealing the mandatory minimum for the simple possession of crack and reducing the sentencing disparity between crack trafficking and powder trafficking from 100-to-1 to 18-to-1. It then traces the history of the paradoxical punishment of crack cocaine, arguing that the 100-to-1 sentencing disparity between powder and crack was deliberately and intentionally created. It also discusses the link between the 100-to-1 sentencing disparity and the so-called “Kingpin Strategy,” along with the violence that came to be associated with crack's low-level distribution system. Finally, the chapter explores the broad consensus among researchers that the lethal violence of the crack era was a product of the systemic features of crack markets themselves.

This introductory chapter explains that the book explores the ways in which rap expresses one of the most powerful symbols of America's paradoxical crime policy: the 100-to-1 sentencing disparity between crack cocaine and powder whereby someone convicted of “simply” possessing five grams of crack had been required by law to serve no less than five years in prison. Drawing on the author's personal experiences with rap and crack, the book examines the degree to which crack cocaine emerged as a primary symbolic referent through the development of an important reflexive lyrical stance that many rap artists in the 1990s took toward their own commercialization. It discusses the cultural consequences of crack's paradoxical punishment, focusing on a reflexive lyrical stance that emerged in 1990s New York rap, which critiqued the music industry for being corrupt, unjust, and criminal. The book also considers how rappers began drawing parallels between the “rap game” and the “crack game,” juxtaposing their own exploits in street crime with the machinations of industry executives.

This chapter explains that from the site of Mons Claudianus, which lies 50 kilometers south of Gebel Dokhan, the Romans hewed the enormous columns of speckled, white granite which were to grace some of the most splendid buildings of Roman antiquity, among them Trajan's Forum and the Pantheon itself. There are approximately 130 quarries in the hills surrounding Mons Claudianus, many of which contain examples of the variety of objects the Romans fashioned from the fine stone but discarded because of cracks or other defects. Recent discoveries indicate that at some point during its occupation, as many as 920 people lived at Mons Claudianus. Scholars do not know exactly when or why quarrying ceased there. The archaeological research at Mons Claudianus itself is becoming increasingly difficult because the site is threatened by modern quarrying, which every year destroys valuable inscriptions in the surrounding area.

Four areas requiring further research are introduced and possible PhD projects are identified. They are (i) workhardening, (ii) electroplasticity, (iii) mobility of dislocations and (iv) hydrogen-assisted cracking. In each case the topic is introduced and key questions are identified. Self-organised criticality and slip bands are considered in the discussion of work hardening. The impact of drag forces is considered in the discussionof dislocation mobility. Possible mechanisms for hyfrogen-assisted cracking include hydrogen-enhanced decohesion (HEDE), adsorption-induced dislocation emission (AIDE) and hydrogen-enhanced localised plasticity (HELP).

In the 1830s, Davy Crockett wrote about stumbling into “earthquake cracks” during a bear hunt. His matter-of-fact reporting of earthquake evidence contrasts with how the New Madrid earthquakes soon became regarded: like Davy Crockett himself, as dubious frontier tall-tale, not as sober history or scientific evidence. The New Madrid earthquakes affected American and Indian history in many ways, but were soon forgotten, for scientific, social, and environmental reasons. Only since the 1970s have they slowly come back into view as a subject for research and, in the early twenty-first century, disaster preparation. Though subject to intense debate, especially with regard to earthquake magnitudes, they are now regarded as a key example in the study of intraplate earthquakes. The history of the New Madrid earthquakes of 1811-1812 illuminates aspects of the history of seismology and earth science, early American and Native American history, and the history of evidence and causation.

This chapter uses first-person accounts, especially by Mississippi River merchant William Leigh Pierce, to narrate the multiple shocks of the New Madrid earthquakes of 1811-1812 which struck present-day Arkansas, Missouri, Kentucky, and Tennessee, especially earthquake cracks, sand blows, booming floods, topographical changes, river disruptions, stunting of forests, and tremors felt out to Canada and the East Coast. Letters and newspaper articles across North America testified to the felt power of the quakes and the widespread interest in understanding them. Pierce and many others thought the environmental and social disruption of the earthquakes would retard American settlement of the middle Mississippi Valley and what was then the “Far West.” Yet a simultaneous river voyage—the first steam-powered Mississippi River trip, by the steamboat New Orleans—demonstrated how wrong Pierce was: American technology and commerce overcame environmental obstacles to produce a flood of settlement, contributing to the later forgetting of the earthquakes.

This chapter describes Armstrong’s boyhood spent singing in a street quartet. One of the songs that he sang was “Swanee River”: a song that was a staple with barbershop singers. This chapter discusses the differences between barbershop arranging, as described by Sigmund Spaeth, and conventional quartet arranging using “Swanee River” as the principle example. This chapter also discusses the relationship between barbershop cadences – or “cracking up a chord” in the vernacular – and “blue notes.”

Most materials fracture suddenly because they contain small internal and surface cracks, which propagate under an applied stress. Griffith’s equation shows how fracture strength depends inversely on the square root of the size of the largest crack. It was developed by Alan Griffith, while he was working as an engineer at Royal Aircraft Establishment Farnborough just after the First World War. This chapter examines brittle and ductile fracture, the concepts of fracture toughness, stress intensity factor and stBiographical Memoirs of Fellows ofrain energy release rate, the different fracture modes, and the use of fractography to understand the causes of fracture in broken components. The importance of fracture mechanics was recognised after the Second World War, following the disastrous failures of the Liberty ships from weld cracks, and the Comet airplanes from sharp window corner cracks. Griffith’s father was a larger-than-life buccaneering explorer, poet, journalist and science fiction writer, and Griffith lived an unconventional, peripatetic and impoverished early life. He became a senior engineer working for the UK Ministry of Defence and then Rolls-Royce Aeroengines, famously turning down Whittle’s first proposed jet engine just before the Second World War as unworkable because the engine material would melt, then playing a major role in jet engine development after the war, including engines for the first vertical take-off planes.