A discussion on detonation

1950 ◽  
Vol 204 (1076) ◽  
pp. 1-33 ◽  
Keyword(s):  
Reaction Zone ◽  
Chemical Reactions ◽  
Detonation Front ◽  
Experimental Studies ◽  
The United States ◽  
Finite Width ◽  
Von Neumann ◽  
War Effort ◽  
Plane Detonation ◽  
Steady Plane

The fundamental physical, chemical and mechanical processes which occur when a detonation wave passes through an explosive were imperfectly understood at the beginning of the recent war. As part of the scientific war effort in the British Common-wealth and in the United States of America, many theoretical and experimental studies were made of detonation processes. Much of the work has recently been declassified and some has been published. Several centres of research in this country and elsewhere are vigorously continuing with these studies. As later papers will show, the quality and general scientific interest of much of this work was considered sufficient to form the basis of a Discussion of the Royal Society. If one neglects the finite width of the zone in the detonation front where chemical reactions occur, a freely running steady plane detonation front can only advance through an explosive with the Chapman-Jouguet velocity defined by D = u + c . Once the explosive products are formed, their subsequent chemical reactions and motion in the detonation front may be considered as adiabatic. Although Chapman (1899) and Jouguet (1901) correctly stated their equation, neither attempted to discuss the reaction zone itself. It was therefore thought necessary that the recent views on the reaction zone should be described in a manner which throws new light on the Chapman-Jouguet equation. Professor J. von Neumann, Dr⋅ S. F. Boys and Dr A. F. Devonshire were the principal contributors on the theoretical side and von Neumann’s theory (1942) will be outlined later.

Family Influences on Youth Offending

2018 ◽  
pp. 377-403
Author(s):  
Abigail A. Fagan ◽  
Kristen M. Benedini
Keyword(s):  
Life Course ◽  
Family Environment ◽  
Parenting Practices ◽  
Experimental Studies ◽  
The United States ◽  
Parental Violence ◽  
Youth Delinquency ◽  
The Impact ◽  
Children’S Exposure

This chapter reviews the degree to which empirical evidence demonstrates that families influence youth delinquency. Because they are most likely to be emphasized in life-course theories, this chapter focuses on parenting practices such as parental warmth and involvement, supervision and discipline of children, and child maltreatment. It also summarizes literature examining the role of children's exposure to parental violence, family criminality, and young (teenage) parents in affecting delinquency. Because life-course theories are ideally tested using longitudinal data, which allow examination of, in this case, the impact of parenting practices on children's subsequent behaviors, this chapter focuses on evidence generated from prospective studies conducted in the United States and other countries. It also discusses findings from experimental studies designed to reduce youth substance use and delinquency by improving the family environment.

Increased Behavioral Sensitivity to Repeated Experiences of Punishment in Children With ADHD: Experimental Studies Using the Matching Law

2021 ◽  
Vol 25 (12) ◽  
pp. 1665-1665
Author(s):  
Emi Furukawa ◽  
Brent Alsop ◽  
Shizuka Shimabukuro ◽  
Paula Sowerby ◽  
Stephanie Jensen ◽  
...  
Keyword(s):  
Response Times ◽  
Experimental Studies ◽  
The United States ◽  
Matching Law ◽  
Limited Attention ◽  
Time On Task ◽  
Children With Adhd ◽  
Behavioral Sensitivity ◽  
Operant Task ◽  
English Speaking

Background: Research on altered motivational processes in ADHD has focused on reward. The sensitivity of children with ADHD to punishment has received limited attention. We evaluated the effects of punishment on the behavioral allocation of children with and without ADHD from the United States, New Zealand, and Japan, applying the generalized matching law. Methods: Participants in two studies (Furukawa et al., 2017, 2019) were 210 English-speaking (145 ADHD) and 93 Japanese-speaking (34 ADHD) children. They completed an operant task in which they chose between playing two simultaneously available games. Rewards became available every 10 seconds on average, arranged equally across the two games. Responses on one game were punished four times as often as responses on the other. The asymmetrical punishment schedules should bias responding to the less punished alternative. Results: Compared with controls, children with ADHD from both samples allocated significantly more responses to the less frequently punished game, suggesting greater behavioral sensitivity to punishment. For these children, the bias toward the less punished alternative increased with time on task. Avoiding the more punished game resulted in missed reward opportunities and reduced earnings. English-speaking controls showed some preference for the less punished game. The behavior of Japanese controls was not significantly influenced by the frequency of punishment, despite slowed response times after punished trials and immediate shifts away from the punished game, indicating awareness of punishment. Conclusion: Punishment exerted greater control over the behavior of children with ADHD, regardless of their cultural background. This may be a common characteristic of the disorder. Avoidance of punishment led to poorer task performance. Caution is required in the use of punishment, especially with children with ADHD. The group difference in punishment sensitivity was more pronounced in the Japanese sample; this may create a negative halo effect for children with ADHD in this culture.

scholarly journals Melting Point of Carbon Particles behind the Gas Detonation Front

2022 ◽  
Vol 16 (2) ◽  
pp. 59-70
Author(s):  
E. S. Prokhorov
Keyword(s):  
Melting Point ◽  
Detonation Front ◽  
Molar Fraction ◽  
Experimental Studies ◽  
Oxygen Mixture ◽  
Detonation Products ◽  
Gas Detonation ◽  
Nanoscale Particles ◽  
Carbon Particles ◽  
Carbon Condensate

A mathematical model of gas detonation of fuel-enriched mixtures of hydrocarbons with oxygen has been formulated, which makes it possible to numerically study the equilibrium flows of detonation products in the presence of free carbon condensation. Reference data for graphite were used to describe the thermodynamic properties of carbon condensate. The calculations are compared with the known results of experimental studies in which, when detonating an acetylene-oxygen mixture in a pipe closed at one end, it is possible to obtain nanoscale particles from a carbon material with special properties. It is assumed that the melting point of such a material is lower than that of graphite and is about 3100 K. Only with such an adjustment of the melting temperature, the best agreement (with an accuracy of about 3 %) was obtained between the calculated and experimental dependence of the detonation front velocity on the molar fraction of acetylene in the mixture.

Food as a Basis for International Co-Operation

Africa ◽  
1944 ◽  
Vol 14 (5) ◽  
pp. 258-264 ◽  
Author(s):  
Margaret Mead
Keyword(s):  
United States ◽  
The United States ◽  
War Effort ◽  
Opening Paragraph

Opening ParagraphIn this paper I propose to describe in some detail how the particular mechanism in which I am interested in the United States is working inside the food situation, and then to go on from that to a consideration of the more general problems involved.The United States began a nutrition campaign just before the war. It is, perhaps, an interesting example of the different effects of timing in the two countries that so many of the measures which we took in connexion with nutrition among our own people were associated with the period of the depression, and with measures of recovery from the depression. In Britain the same kind of measures have been associated with the war, and have been subsequent to the height of the British war effort; they are therefore associated with the crest of a successful war effort, whereas we associate them with the less uplifting feeling of coping with the depression.

African American Soldiers in World War I

2021 ◽  
Author(s):  
Amanda M. Nagel
Keyword(s):  
United States ◽  
African American ◽  
Military Service ◽  
The United States ◽  
First World War ◽  
World War ◽  
The First World War ◽  
War Effort ◽  
African American Soldiers ◽  
First World

In the midst of the long black freedom struggle, African American military participation in the First World War remains central to civil rights activism and challenges to systems of oppression in the United States. As part of a long and storied tradition of military service for a nation that marginalized and attempted to subjugate a significant portion of US citizens, African American soldiers faced challenges, racism, and segregation during the First World War simultaneously on the home front and the battlefields of France. The generations born since the end of the Civil War continually became more and more militant when resisting Jim Crow and insisting on full, not partial, citizenship in the United States, evidenced by the events in Houston in 1917. Support of the war effort within black communities in the United States was not universal, however, and some opposed participation in a war effort to “make the world safe for democracy” when that same democracy was denied to people of color. Activism by organizations like the National Association for the Advancement of Colored People (NAACP) challenged the War Department’s official and unofficial policy, creating avenues for a larger number of black officers in the US Army through the officers’ training camp created in Des Moines, Iowa. For African American soldiers sent to France with the American Expeditionary Forces (AEF), the potential for combat experience led to both failures and successes, leading to race pride as in the case of the 93rd Division’s successes, and skewed evidence for the War Department to reject increasing the number of black officers and enlisted in the case of the 92nd Division. All-black Regular Army regiments, meanwhile, either remained in the United States or were sent to the Philippines rather than the battlefields of Europe. However, soldiers’ return home was mixed, as they were both celebrated and rejected for their service, reflected in both parades welcoming them home and racial violence in the form of lynchings between December 1918 and January 1920. As a result, the interwar years and the start of World War II roughly two decades later renewed the desire to utilize military service as a way to influence US legal, social, cultural, and economic structures that limited African American citizenship.

Conservative Catholicism and American Philanthropy

2015 ◽  
Author(s):  
Udi Greenberg
Keyword(s):  
United States ◽  
Soviet Union ◽  
The United States ◽  
Educational Programs ◽  
West Germany ◽  
The Soviet Union ◽  
War Effort ◽  
The Cold War ◽  
The Guardian ◽  
Effective Path

This chapter focuses on political theorist Waldemar Gurian, one of the first Catholic émigrés to return from exile to visit Germany in 1948. During the occupation period and the early 1950s, Gurian utilized U.S. wealth to fund a stream of publications, lectures, and educational programs intended to establish a union between the United States and Europe's Catholics. His writings depicted the United States as the guardian of Catholic ideals, autonomy, and communities and insisted that an alliance with the United States presented the only effective path toward defeating Catholicism's ultimate enemy, the Soviet Union. With the massive support of the American diplomatic and cultural apparatus, Gurian and other émigrés worked to popularize these ideas among German Catholics. By the mid-1950s, their efforts helped forge an alliance between Catholics, West Germany, and the United States, a bond that became the backbone of the Cold War effort in Europe.

The Beginnings of the Catholic Renaissance

1996 ◽  
Author(s):  
Philip Gleason
Keyword(s):  
United States ◽  
The United States ◽  
Public Affairs ◽  
New Era ◽  
American Life ◽  
War Effort ◽  
The Creation ◽  
National Headquarters ◽  
Emotional Solidarity ◽  
The Church

The beginnings of the Catholic Renaissance in the United States were closely linked to the experience of American Catholics in the First World War. As we saw in Chapter 3, mobilization of Catholic energies to meet the wartime crisis led to the creation of the National Catholic War Council. The NCWC’s success in coordinating Catholic participation in the war effort, and the recognition it gained as the representative agency of the church in matters of broad national interest persuaded Catholic leaders that it should be perpetuated after the war. That was accomplished in 1919, when the War Council was transformed into the National Catholic Welfare Council (later National Catholic Welfare Conference). The creation of a national headquarters and staff not only gave the church a more effective voice in public affairs, it also enhanced Catholic visibility and served notice that a new era of purposeful Catholic participation in American life was about to begin. These developments had a tonic effect on Catholic morale and reinforced the sense of emotional solidarity with, and responsibility to, the nation that had grown out of the shared experience of wartime mobilization. The earliest manifestations of the Catholic Revival in the United States emerged from this matrix and took the form of a new kind of Catholic Americanism. There were, of course, certain points of similarity between the Americanism of the war and postwar years and that of the 1890s. Both versions, for example, reflected intense patriotic feeling, and both urged Catholics to identify with, and participate in, American life. Moreover, Cardinal Gibbons, who presided over the creation of the War Council and its transformation into the permanent NCWC, constituted a living link between the two eras. Yet no real effort was made to portray the new Americanism as a continuation of the earlier version. Reticence on this point made good sense tactically, since in 1899 Pope Leo XIII had condemned the opinions that “some comprise under the head of Americanism.”

ACE

2017 ◽  
Author(s):  
Martin Campbell-Kelly
Keyword(s):  
The United States ◽  
National Physical Laboratory ◽  
University Of Pennsylvania ◽  
Small Scale ◽  
Vast Number ◽  
Von Neumann ◽  
Princeton University ◽  
Alan Turing ◽  
Physical Laboratory ◽  
Novel Concept

In October 1945 Alan Turing was recruited by the National Physical Laboratory to lead computer development. His design for a computer, the Automatic Computing Engine (ACE), was idiosyncratic but highly effective. The small-scale Pilot ACE, completed in 1950, was the fastest medium-sized computer of its era. By the time that the full-sized ACE was operational in 1958, however, technological advance had rendered it obsolescent. Although the wartime Bletchley Park operation saw the development of the electromechanical codebreaking bombe (specified by Turing) and the electronic Colossus (to which Turing was a bystander), these inventions had no direct impact on the invention of the electronic storedprogram computer, which originated in the United States. The stored-program computer was described in the classic ‘First draft of a report on the EDVAC’, written by John von Neumann on behalf of the computer group at the Moore School of Electrical Engineering, University of Pennsylvania, in June 1945. The report was the outcome of a series of discussions commencing in the summer of 1944 between von Neumann and the inventors of the ENIAC computer—John Presper Eckert, John W. Mauchly, and others. ENIAC was an electronic computer designed primarily for ballistics calculations: in practice, the machine was limited to the integration of ordinary differential equations and it had several other design shortcomings, including a vast number of electronic tubes (18,000) and a tiny memory of just twenty numbers. It was also very time-consuming to program. The EDVAC design grew out of an attempt to remedy these shortcomings. The most novel concept in the EDVAC, which gave it the description ‘stored program’, was the decision to store both instructions and numbers in the same memory. It is worth noting that during 1936 Turing became a research student of Alonzo Church at Princeton University. Turing came to know von Neumann, who was a founding professor of the Institute for Advanced Study (IAS) in Princeton and was fully aware of Turing’s 1936 paper ‘On computable numbers’. Indeed, von Neumann was sufficiently impressed with it that he invited Turing to become his research assistant at the IAS, but Turing decided to return to England and subsequently spent the war years at Bletchley Park.

Epilogue

2018 ◽  
Author(s):  
Colin F. Baxter
Keyword(s):  
United States ◽  
World War Ii ◽  
The United States ◽  
World War ◽  
Total War ◽  
War Effort

The extraordinary story of RDX during World War II is composed of many striking chapters, one of which is the unprecedented collaboration between Britain, Canada, and the United States. At each stage, however, the proponents of RDX had to surmount formidable technical and human obstacles before the super-explosive and its offspring, Composition B and Torpex, could make an impact on the Allies’ war effort. Although researchers at the Woolwich Arsenal had desensitized the dangerous explosive by mixing it with TNT and some beeswax, the Ministry of Supply was unable to supply the vast quantities that were needed for total war....

Kentucky Joins the Great War

2016 ◽  
Author(s):  
David J. Bettez
Keyword(s):  
United States ◽  
World War I ◽  
The United States ◽  
Red Cross ◽  
German Language ◽  
American Population ◽  
World War ◽  
Support Organizations ◽  
War Effort ◽  
The Great War

This chapter covers the commonwealth’s response to World War I and efforts to support the war after the United States entered it in April 1917. It describes support from newspaper editors Henry Watterson and Desha Breckinridge. It also discusses attitudes toward the state’s extensive German American population, including an effort to ban the teaching of the German language in schools and the repression of people deemed disloyal or insufficiently supportive of the war. Kentuckians also rallied to the war effort in a positive way, supporting Liberty Bond and Red Cross campaigns. They joined support organizations such as the Four Minute Men and the American Protective League.

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