Near-field angular distributions of high velocity ions for low-power hall thrusters

Experimental angular distributions of high-energy primary ions in the near-field region of a small Hall thruster between 50-200 mm downstream of the thruster exit plane at a range of centerline angles have been determined using a highly-collimated, energy-selective diagnostic probe. The measurements reveal a wide angular distribution of ions exiting the thruster channel and the formation of a strong, axially-directed jet of ions along the thruster centerline. Comparisons are made to other experimental determinations as applicable

Induced Variational Method from Supersymmetric Quantum Mechanics and the Screened Coulomb Potential

The formalism of Supersymmetric Quantum Mechanics supplies a trial wave function to be used in the Variational Method. The screened Coulomb potential is analysed within this approach. Numerical and exact results for energy eigenvalues are compared.Comment: 7 pages, LATE

Labor Market Effects of Immigration: Evidence from Neighborhood Data

This paper combines individual-level data from the German Socio-Economic Panel (SOEP) with economic and demographic postcode-level data from administrative records to analyze the effects of immigration on wages and unemployment probabilities of high- and low-skilled natives. Employing an instrumental variable strategy and utilizing the variation in the population share of foreigners across regions and time, we find no support for the hypothesis of adverse labor market effects of immigration.

Labor Market Effects of Immigration – Evidence from Neighborhood Data

This paper combines individual-level data from the German Socio-Economic Panel (SOEP) with economic and demographic postcode-level data from administrative records to analyze the effects of immigration on wages and unemployment probabilities of high- and low-skilled natives. Employing an instrumental variable strategy and utilizing the variation in the population share of foreigners across regions and time, we find no support for the hypothesis of adverse labor market effects of immigration.International migration; effects of immigration

Land titling as women's empowerment: critical observations from Recife Brazil

This thesis critically highlights the promises and shortcomings of women???s formal ownership of land (land titling) as a means towards women???s empowerment. The literature extensively documents the costs and benefits of land titles for poor women and delineates the gendered impacts of property ownership. The literature lacks insight into two important questions. First, how do the cost and benefit of titles interact to (dis)empower women? Second, what role does the titling processes itself play in empowering women? These two gaps are explored in this thesis. I use Lukes??? three-tiered concept of power as a framework for examining how titles and titling shift the relative power of the individual and embedded in interpersonal and institutional relationships. I use Lukes??? to examine the Ponte do Maduro Project, in Recife, Brazil, where a strong landless women???s movement gained legal recognition for the community and is engaged in co-constructing and carrying out their own titling process. Interviews with women in Ponte do Maduro reveal the complexities, contradictions and contingencies of titling. I find that titles are important but are not empowering. However, the titling process can be empowering because it has the potential to address the multiple sites where oppression occurs. Ultimately, it is awareness of the contingencies of (dis)empowerment embedded in the titling processes that can help those involved in conceptualizing and doing gender empowerment work to better serve the women they wish to empower

Leaching of an Acetanilide Herbicide, CP55097 in Soil Columns

The leachability of the acetanilide herbicide, CP55097 was determined using a soil column system. This herbicide, which is used as a preemergent against certain grasses and broadleaf weeds, was leached through four different soils (sandy clay, sandy loam, sandy clay loam and clay loam) using the following procedure. Plastic columns consisting of 8 rings (2 in. dia. x 1 in.) were assembled and their bottoms covered with cheesecloth. They were then filled with soil and prewetted with water to attain field capacity. Herbicide concentrations equalling 0, 1, 3, 6 lb/A were pipetted onto the soil surface and 0, 1, 2, 4 in/A of water was applied at an approximate rate of 1 ml/minute. The columns were leached for two days, then disassembled and the soil placed in styrofoam cups. The extent to which CP55097 leached through the soil columns was determined by an oat bioassay (Avena sativa var. Noble). After the soil dried for two days, 10 oat seeds were planted with the hilum end down. The plants were grown at a temperature of approximately 80 F and illuminated with cool white fluorescent light at 300 ft-c on a 15 hour photoperiod cycle. The plants were watered twice a day for a duration of eight days after which the shoots were weighed and the percent germination recorded. The organic matter and clay content of the soils was found to have a significant effect on the movement of the herbicide. In general, the herbicide moved less in soils with higher organic matter and/or clay content. Of the two, organic matter was more effective in reducing herbicide movement. Only in the low clay-low organic matter sandy loam was the herbicide leached throughout the eight inches of soil. Statistically at a significance level of 0.05 all factors; soil type, CP55097 concentration, water application and soil depth separately and all interactions thereof significantly affected oat growth. However, the depth of leaching as determined by growth reduction, was not correlated with the concentration of CP55097 applied. Even though increasing concentrations of herbicide did reduce oat growth at specific depths, the maximum depth of observable effect was constant for each initial concentration tested

FIRST-GENERATION BLACK MALE STUDENTS’ EXPERIENCES, AND RELATIONSHIPS THAT SHAPED COLLEGE – TO - CAREER TRANSITION

First-generation, Black, male students continue to lag behind their continuing-generation peers in degree attainment, leaving them deficient in obtaining the social and financial upward mobility higher education is expected to afford. Research finds that, despite Black males entering college with higher degree aspirations than their White peers, they were 6 times less likely to achieve them, and only 5% of Black males would eventually graduate with a degree or certificate within three years of enrollment, compared with 32% of White males (Center for Community College Student Engagement, 2014). To close this persistent gap, this research sought to understand the activities, experiences, and relationships engaged in by members of this population who were successful in completing college and transitioning into what they defined as successful careers. This case study was conducted with 10 Midwest college graduates through semi-structured interviews to capture their unique voices and experiences across their college-to-career transition. Themes emerged around leveraging social and cultural capital among faculty, staff, and career professionals of similar race, background. The continuity of experiences between these groups appeared to account for as much as 80% of participants’ access to career services. These findings indicate the need for higher education institutions to employ strategic steps to align support personnel with first generation students’ (FGS) cultural norms and experiences to establish a sense of belonging and develop a nucleus of trust