Microprocessor-based Pressure Controller

A device for automatic control of pressure in an ion-atom scattering experiment has been constructed. The system was modeled to achieve the minimum time for transition from one pressure to another. The pressure controller learns the system response and iterates the parameters used in profiling the valve voltage to reduce the transition time. The device has been used with two different scattering chambers and has worked well with both

Global Crisis Writ Large: The Effects of Being Stateless in Thailand on Hill-Tribe Children,

According to the United Nations High Commission for Refugees (UNHCR), [n]o region of the world has been left untouched by the statelessness issue. International law defines a stateless person as someone who is not considered as a national by any state under the operation of its law. Yet across the nations, stateless persons do not desire citizenship simply for the sake of citizenship. Ultimately, citizenship, or membership in a nation, provides a link between an individual and that nation and carries with it fundamental benefits and rights. Correspondingly,lack of citizenship translates into a denial of benefits and rights, including basic human rights. The global crisis of statelessness is emphasized and highlighted by the struggle for citizenship of Thailand’s hill-tribes. The hill-tribes, or chao khao, are minority ethnic groups that live in villages in the mountains of northern Thailand. Almost half of all hill-tribe people are stateless. Thailand is their true home, and for most, has been their home for generations. Most hill-tribe people were born in Thailand, and one or both of their parents were also born in Thailand. Thus, they are legally eligible for Thai citizenship under Thai law. In reality, however, forty to sixty percent of hill-tribe people who qualify for Thai citizenship remain without it. In point of fact, many hill-tribe people already are Thai citizens under the law: Thai laws actually provide detailed specifications regarding who is eligible for citizenship. For these people legal eligibility is not the issue. The central issue is whether, in practice, the Thai government recognizes their citizenship and provides them with corresponding documentation or proof. There are approximately 400,000 stateless hill-tribe people in Thailand today. These hill-tribes are denied many benefits and rights on account of their legal status. For example, they are ineligible for the Thai national healthcare plan that benefits people below a certain income level because only Thai citizens are eligible for the plan. Many hill-tribe people, therefore, have either no access to healthcare, limited access through non-governmental organizations (“NGOs”), or access healthcare but are forced to pay an unaffordable rate. Lack of citizenship also restricts the freedom of movement of hill-tribes outside their villages and provinces. It is already difficult for hill-tribes to obtain non-agricultural jobs. Travel restrictions applicable to non-citizens further narrow their opportunities to access other employment and education. Lack of Thai citizenship also prevents hill-tribe people from joining labor unions, owning land, and voting in political elections. The denial of these fundamental rights places hill-tribe people at a higher risk for social and economic exploitation in the forms of sex trafficking and abusive labor. The United Nations Educational Scientific and Cultural Organization ( UNESCO ) reports that [i]n Thailand . . . a lack of proof of citizenship is the single greatest risk factor for a hill-tribe girl or woman to be trafficked or otherwise exploited. This increased risk of sexual exploitation translates into a greater likelihood that hill-tribe women and girls will contract HIV/AIDS. In addition to being at greater for commercial exploitation, one of the greatest obstacles to social advancement facing stateless hill-tribe children is access to basic, quality education. Although Thailand’s Ministry of Education has mandated that all children have the right to twelve years of free education, the first nine being compulsory, many hill-tribe children do not benefit from this policy. Many schools are either unaware of these recent education regulations or know about the laws but choose to discriminate against hill-tribe children. As a result, some hill-tribe children struggle simply to enroll in a Thai public school. If children do succeed in enrolling in primary school, the quality of education they receive often does not match that of other schools. The quality of schools in hill-tribe villages, which are located in remote highland areas, is far inferior to Thai public schools located in and near large cities. Hill-tribe children who overcome these obstacles and graduate face further complications as many school officials stamp their diploma with bright red letters indicating that the student is not a Thai citizen. The Thai government has taken a step in the right direction by clarifying that education is for all and that all includes children who lack Thai citizenship. Furthermore, many active international organizations ( IOs ) and NGOs are working to assist the hill-tribes. Some of these organizations provide healthcare, some provide education, and some assist hill-tribe people with the citizenship application process. Yet hill-tribe people and their children continue to encounter the same problems. This Article argues that the Thai government and NGOs must attack the root of the problem: lack of citizenship. While providing hill-tribes with social services fulfills a great need, it only treats the symptoms or effects of statelessness. The solution is to recognize hill-tribe people as Thai citizens. This Article clarifies the current state of Thai citizenship and education laws and sheds light upon the unjust treatment stateless hill-tribe people face in these areas. It highlights the denial of rights through the lens of education, examining the various struggles of hill-tribe children. The Article provides background information about the hill-tribes and outlines the current citizenship and education laws that apply to them. It then analyzes the implementation of Thai citizenship and education laws, discussing the main obstacles to their success. The Article also discusses in detail a recent 2008 UNESCO study on the magnitude and effects of statelessness on the hill-tribes. Finally, the Article makes practical proposals directed towards Thailand’s government and NGOs that are working with the hill-tribes towards the recognition of their legal and human rights. These proposals include educating Thai government and education officials on the statelessness problem and the relevant laws, ensuring that all children are registered at birth, and bringing together international and local NGOs for broader collaboration

Reactive Scattering Cell For Atomic Hydrogen And Deuterium

A design for a high-temperature reactive scattering cell for atomic hydrogen and atomic deuterium is described. At approximately 2700 K a dissociation of the molecular target species of over 95% has been obtained. The lifetime of 340 h of operation is sufficient for precision, long-time, differential cross-section measurements

Excitation Of Atomic Hydrogen To The N=2 States By 15-200-keV Protons

Cross sections for the process H+ + H H+ + H* (n=2) are determined from the energy-loss spectra of 15-200-keV protons. After normalization at 200 keV to the Born approximation, the maximum value (1.07 x 10-16 cm2 at 60 keV) lies below close-coupling calculations and above Glauber-approximation calculations. The agreement with low-energy (5-30-keV) data of others is very good. © 1975 The American Physical Society

Angular Differential Cross Sections for 25-, 50-, and 100-kev-proton Excitation of Helium to the n=2 Level

Differential cross sections for 25-, 50-, and 100-keV-proton excitation of helium to the n=2 level have been determined for center-of-mass scattering angles from 0 to 1.2 mrad. The cross sections were obtained from an analysis of the angular distribution of the scattered protons which had lost an energy corresponding to the excitation of the helium target to its n=2 level. The differential cross section is very sharply peaked in the forward direction and decreases by a factor of 45 in 1.0 mrad at 25 keV and by a factor of 650 in 1.0 mrad at 100 keV. The data are in excellent agreement with a recent multistate eikonal calculation

Cross Sections for Excitation of Atomic Hydrogen to the n=2, 3, and 4 States by 15-200-keV Protons

Cross sections for the processes H++H(1 s)H++H*(n = 2, 3, 4) have been extracted from the energy-loss spectra of 15- to 200-keV protons by using a spectrum-fitting technique. Absolute cross sections have been obtained by normalization of the spectra to the theoretical cross section through the use of the Born approximation at 200 keV. The cross-section curves are very similar in shape with maxima at 60 keV. The results have been compared with available theoretical calculations. The n = 2 and n = 3 cross-section measurements are in very good agreement in curve shape with Glauber-approximation calculations

Angular Differential Cross Sections for Excitation of Atomic Hydrogen to the n=2 Level by Proton Impact

Differential cross sections for 15-145-keV proton impact excitation of atomic hydrogen to the n=2 level have been determined for center-of-mass scattering angles 0 to 1.2 mrad. The cross sections were obtained from an analysis of the angular distribution of protons which had lost an energy corresponding to the excitation of atomic hydrogen to its n=2 level. The differential cross sections obtained are in rather good agreement with available coupled-state calculations as well as the simpler Glauber-approximation calculations. However, at the larger scattering angles the cross sections obtained from the theoretical treatments appear to decrease more rapidly than the experimental data