LOW-VOLTAGE CATHODOLUMINESCENT PROPERTIES OF BLUE-EMITTING YTTRIUM SILICATES DOPED WITH CERIUM

ABSTRACT Yttrium silicate activated with Ce 3+ , (Y 1-x Ce x ) 2 SiO 5 , has been found to be an efficient phosphor that can potentially be used as the blue-emitting component in field emission flat panel displays. This highly refractory powder can be synthesized by combustion synthesis, a low cost technique used to fabricate multicomponent oxide powders in a single step process. The effect of activator concentration and post-synthesis annealing was examined on the fluorescent properties. The powders were found to be monoclinic space group P2 1 /c in the as-synthesized state, and transformed to monoclinic space group C2/c after annealing. The maximum luminous emission intensity was reached after a one hour anneal at 1350 C for x=0.0075, with the peak Ce 3+ emission wavelength between 420 and 450 nm. When co-doped with Gd 3+ , no increase in the emission intensity was observed

An Exploratory Initiative for Improving Low-Cost Housing in Texas

In 1996 the Real Estate Center at Texas A&M University released a report indicating that the population of Texas would double in the next 30 years and that a majority of the 18 million new Texans would be have low to very-low incomes. In order to house that many low income persons, it is apparent that a significant number of affordable housing units must be built in a relatively short time frame. Based on these predictions, our interdisciplinary team made a proposal in the Texas Engineering Experiment Station (TEES) Strategic Initiatives Program to explore technologies related to the production of affordable housing. The purpose of the work is to identify opportunities for research into systems, materials, and processes that might contribute to the development of a low-cost housing industry in Texas that could meet state housing needs and might create export possibilities. The proposal was funded by the Texas Engineering Experiment Station, the Center for Housing and Urban Development, and the College of Architecture Research Fund. This report summarizes the results of the effort

Counter-Insurgency against ‘kith and kin’?: the British Army in Northern Ireland, 1970–76

This article argues that state violence in Northern Ireland during the period 1970–1976—when violence during the Troubles was at its height and before the re-introduction of the policy of police primacy in 1976—was on a greatly reduced scale from that seen in British counterinsurgency campaigns in the colonies after the Second World War. When the army attempted to introduce measures used in the colonies—curfews, internment without trial—these proved to be extremely damaging to London's political aims in Northern Ireland, namely the conciliation of the Catholic minority within the United Kingdom and the defeat of the IRA. However, the insistence by William Whitelaw, secretary of state for Northern Ireland (1972–73), on ‘throttling back'—the release of internees and the imposition of unprecedented restrictions on the use of violence by the army—put a serious strain on civil-military relations in Northern Ireland. The relatively stagnant nature of the conflict—with units taking casualties in the same small ‘patch’ of territory without opportunities for the types of ‘positive actions’ seen in the colonies—led to some deviancy on the part of small infantry units who sought informal, unsanctioned ways of taking revenge upon the local population. Meanwhile, a disbelieving and defensive attitude at senior levels of command in Northern Ireland meant that informal punitive actions against the local population were often not properly investigated during 1970–72, until more thorough civilian and military investigative procedures were put in place. Finally, a separation of ethnic and cultural identity between the soldiers and the local population—despite their being citizens of the same state—became professionally desirable in order for soldiers to carry out difficult, occasionally distasteful work

Professionalization of a nonstate actor

Can nonstate militants professionalize? That is the core question of this piece. Discussions of professionalism have spread to the state military from civilian professions such as education, medicine, and law. This piece examines whether nonstate actors exhibit the same fundamental processes found within these state-based organizations. These fundamentals are the creation of a recognized internal ethos, which acts as a collective standard for those involved. A commitment to expertise and the punishment of those who do not reach these collective expectations reinforce this ethos. To answer this question, this piece examines the development of the Provisional Irish Republican Army (PIRA) during the Troubles. It highlights consistencies and inconsistencies with traditional forces and argues that groups like the PIRA can professionalize and increase their effectiveness in doing so. This widens the field of professionalism studies and provides an additional lens through which to examine nonstate groups

Editorial: African women's struggles in a gender perspective

International audienc

Climate and colonialism

Recent years have seen a growth in scholarship on the intertwined histories of climate, science and European imperialism. Scholarship has focused both on how the material realities of climate shaped colonial enterprises, and on how ideas about climate informed imperial ideologies. Historians have shown how European expansion was justified by its protagonists with theories of racial superiority, which were often closely tied to ideas of climatic determinism. Meanwhile, the colonial spaces established by European powers offered novel ‘laboratories’ where ideas about acclimatisation and climatic improvement could be tested on the ground. While historical scholarship has focused on how powerful ideas of climate informed imperial projects, emerging scholarship in environmental history, history of science and historical geography focuses instead on the material and cognitive practices by which the climates of colonial spaces were made known and dealt with in fields such as forestry, agriculture and human health. These heretofore rather disparate areas of historical research carry great contemporary relevance of studies of how climates and their changes have been understood, debated and adapted to in the past

Toward a geography of black internationalism: Bayard Rustin, nonviolence and the promise of Africa

This article charts the trip made by civil rights leader Bayard Rustin to West Africa in 1952, and examines the unpublished ‘Africa Program’ which he subsequently presented to leading American pacifists. I situate Rustin’s writings within the burgeoning literature on black internationalism which, despite its clear geographical registers, geographers themselves have as yet made only a modest contribution towards. The article argues that within this literature there remains a tendency to romanticize cross-cultural connections in lieu of critically interrogating their basic, and often competing, claims. I argue that closer attention to the geographies of black internationalism, however, allows us to shape a more diverse and practiced sense of internationalist encounter and exchange. The article reconstructs the multiplicity of Rustin’s black internationalist geographies which drew eclectically from a range of Pan-African, American and pacifist traditions. Though each of these was profoundly racialized, they conceptualized race in distinctive ways and thereby had differing understandings of what constituted the international as a geographical arena. By blending these forms of internationalism Rustin was able to promote a particular model of civil rights which was characteristically internationalist in outlook, nonviolent in principle and institutional in composition; a model which in selective and uneven ways continues to shape our understanding of the period

Race at the margins: A Critical Race Theory perspective on race equality in UK planning.

Despite evidence of the growing ethnic diversity of British cities and its impact on urban governance, the issue of racial equality in UK planning remains marginal, at best, to mainstream planning activity. This paper uses Critical Race Theory (CRT) to consider the reasons why the ‘race’ and planning agenda continues to stall. CRT, it is argued, offers a compelling account of why changes in practice over time have been patchy at best, and have sometimes gone into reverse