Calorimetric determination of the heat of solution of calcium in liquid ammonia and the heat of reaction of calcium with the ammonium ion in liquid ammonia

Thesis (M.A.)--Boston University, 1949. This item was digitized by the Internet Archive

The thermochemistry of calcium strontium and barium in liquid ammonia at -33°C.

Thesis (Ph.D.)--Boston UniversityThe solutions of the alkali and alkaline earth metals in liquid ammonia are characterized by certain anomalous properties which are generally similar for these groups of metals. The similarity of the properties of these metal-ammonia solutions has been found to be due to the presence of a common negative species, the electron associated with the solvent in some undetermined manner (the "solvated" electron). In this dissertation the investigations of the ammonia solutions of the alkaline earth metals have been reviewed. Early studies have indicated that calcium, strontium, and barium metals combine with ammonia to form their respective hexammoniates, M(NH3)6. The heats of formation of these compounds, as determined from vapor pressure data, are: - 10.3 kcal.,- 9.9 kcal., and - 9.6 kcal., respectively. Magnesium metal, which is only sparingly soluble in liquid ammonia, also forms a hexammoniate. The following general remarks can be applied to all the alkaline earth metal ammoniates: the compounds a re identical in appearance with the solutions from which they are precipitated; the optical and electrical properties are the same for both the solid and the solution, therefore being independent of the physical state of the system and probably being determined by the same factors

Developing an Occupational Therapy Community/Client Wellness Program

Health promotion is gaining more recognition with the increase of chronic diseases worldwide and the growing elderly population in the United States. The World Health Organization (2011) places a particular emphasis on health promotion as well as preventative care. The role of occupational therapy fits directly with this emphasis. The American Occupational Therapy Association (2008) identified occupational therapy\u27s roles to include promotion of healthy lifestyle, use of occupation as a means to improve health and provide services to both individuals and populations. Problem: Although health promotion and prevention is well within the realm of occupational therapy, Flannery and Barry (2003) found that only 54 percent of occupational therapists reported involvement with health promotion. The most common barriers to health promotion included limited resources, lack of knowledge and structure, and the presence of role confusion (Flannery & Barry 2003; Casey, 2000). Of the 54 percent of occupational therapists who reported involvement with health promotion, none indicated community affiliation (Flannery & Barry, 2003). However, it was found that the community setting was the most appropriate for occupational therapists to implement health promotion. Methodology: A comprehensive literature review was conducted to identify if there was a need for training occupational therapists regarding community health promotion and prevention programs. Emphasis was placed on implementation and locating funding sources. Additional literature was researched to identify an appropriate theoretical basis regarding adult learning principles and strategies to ensure the appropriate delivery of information to the audience. Results: Developing an Occupational Therapy Community/client WeIlness Program workshop was designed to educate occupational therapists on the process of designing and implementing a community-based health promotion program. The workshop will also provide education on locating and accessing funding for such a program. The workshop is designed from a facilitator\u27s perspective so anyone could take the information and provide the workshop. Additional resources, information and learning activities are included and are based on Knowles\u27s (1980) adult learning theory

Informal Pathways to Engineering: Interim Findings from a Longitudinal Study

Informal Pathways to Engineering: Interim Findings This study, based on social cognitive career theory, seeks to investigate the effect of informal, out­of­school activities, as well as other factors (self­efficacy, outcome expectations, and personal interests, and intrapersonal factors) on students’ interest in engineering and decisions to engage in engineering­related activities. The study uses a longitudinal design in which children, parents, and educators (classroom teachers, school principals, and informal educators) are interviewed and surveyed over a period of three years (corresponding with the middle school years). Thirty families from Massachusetts and 30 families from Indiana were enrolled in the study in Year 1. Due to attrition, 40 families are currently enrolled across both sites. Children were enrolled in the study if their parents indicated that their children were interested in engineering­related activities (instead of “engineering” we used the phrase “designing, creating, or building”). For example, 100% of the sample had played with engineering­related toys (such as Legos, K’NEX, robots); 85% of the sample had watched a TV show, webisode or DVD related to designing, creating, or building; and 75% had previously built something, not in school. At the start of the study, most children (80%) reported that they knew what engineering was or had heard of it and the same proportion agreed or strongly agreed that “engineering is cool.” Upon enrollment in the study, 21 children (35%) reported that they would like to be an engineer someday. This paper will explore the intrapersonal, psychosocial, and external factors that may have played a role in children’s interest in engineering activities. For example, we will explore parental influence on children’s engineering interests and will examine the question of whether children who are interested in engineering have had exposure to parents or relatives with an engineering background. (Nine of the 60 children (15%) in the sample had one or more parents who was an engineer, while slightly more than half of the sample (51%) reported that they did not have any regular interaction with engineers.) In addition, we will look at the relationship between parental engineering knowledge, engineering­related self­efficacy, and children’s interests, examining the question of whether children who are interested in engineering have parents who feel confident in their engineering­related knowledge. For example, all but one parent in the study agreed that engineering improves society, yet only slightly more than half of the parents (55%) reported that they actually knew what engineers do. One­third of parents reported that they didn’t know how to help their children learn about engineering; they didn’t know how engineering could be used to help society; and they didn’t know how engineering is different from science. The broader significance and importance of this project will be to support the engineering field’s ability to inspire more children to pursue engineering pathways, from initial interest in engineering clubs and other extracurricular activities to choices in college majors and an ultimate career as a professional engineer. In addition, the project will help us consider how we might provide resources and education to parents to help them support their children

Automated Space-mapping framework for electromagnetic device optimisation

Thesis (MEng)--Stellenbosch University, 2019.ENGLISH ABSTRACT: A space-mapping (SM) framework that allows an automated approach to solving computer-aided design (CAD) optimisation problems for electromagnetic (EM) devices is presented. Direct optimisation of detailed, high-fidelity/fine EM models can be computationally expensive and can restrict the adoption of optimisation for large systems. SM allows the incorporation of low-fidelity/coarse models that are quick to evaluate, without sacrificing the accuracy of results. The SM framework builds up a surrogate model from a coarse model that is aligned programmatically to the fine model. Optimisation is carried out using the surrogate model. If the surrogate is evaluated far away from where the alignment took place, the results may diverge. A trust-region (TR) is introduced as a method of improving the robustness of the framework. The TR governs the bounds of the optimisation space. Four types of SM are implemented within the automated framework: input, output, implicit and frequency SM. Literature using some of these techniques is investigated, and a detailed analysis on the original SM implementation and a frequency SM approach is included. A basic TR implementation, from literature, is also investigated in detail. The methodology used to develop the automated framework is explained, and Matlab implementation details for each stage are discussed. Model alignment and surrogate building for each of the SM techniques are discussed. The user's interface to the TR enhanced SM optimisation system is detailed. The available high-fidelity solvers are FEKO and CST, while those for low-fidelity are AWR-MWS and Matlab. A microstrip stub example is used to demonstrate input, implicit and frequency SM. FEKO and AWR-MWS are used for these examples. A microstrip double folded stub filter is taken from literature and used to evaluate the system. This bandstop example has three design variables and is required to meet three S-parameter goals. An additive input and implicit SM approach is chosen to solve this problem. Each iteration is analysed and the SM framework successfully meets specification within four fine model evaluations. Finally, improvements to the automated framework are presented. A general mathematical model is suggested for unit-testing, and an object orientated design is suggested.AFRIKAANSE OPSOMMING: 'n Ruimteafbeelding (SM) raamwerk wat 'n outomatiese benadering vir die oplos van rekenaar gesteunde ontwerp (CAD) optimeringsprobleme vir elektromagnetiese (EM) toestelle toelaat word aangebied. Direkte optimering van gedetailleerde, hoëtrou EM modelle kan bewerkingsintensief wees, en kan die gebruik van optimering in groot stelsels beperk. SM laat die inkorporasie van lae-vertroue/growwe modelle toe wat vinnig is om te evalueer, sonder om die akkuraatheid van die resultate in te boet. Die SM raamwerk bou 'n surrogaatmodel vanaf die growwe model op, wat programmaties belyn word met die hoëtrou/fyn model. Optimering word uitgevoer deur van die surrogaatmodel gebruik te maak. As die surrogaat ver van enige punt waar belyning plaasgevind het geëvalueer word, mag die resultate divergeer. A vertrouegebied (TR) word voorgestel as 'n metode om die robuustheid van die raamwerk te versterk. Die TR beheer die grense van die optimeringsruimte. Vier tipes SM word geïmplementeer binne die outomatiese raamwerk: intree, uittree, implisiete en frekwensie SM. Literatuur wat gebruik maak van party van die tegnieke word bestudeer, en 'n gedetailleerde analise van die oorspronklike SM implementasie en 'n frekwensie SM implementasie word ingesluit. 'n Basiese TR implementasie, van die literatuur, word ook in detail ondersoek. Die metodiek wat gebruik is om die outomatiese raamwerk te ontwikkel word verduidelik, en Matlab implementeringsdetails vir elke stadium word bespreek. Die gebruikerskoppelvlak na die TR-verbeterde SM optimerings stelsel word bespreek. Die beskikbare hoëtrou oplossers is FEKO en CST, terwyl, vir die growwe modelle, AWR-MWS en Matlab gebruik word. 'n Mikrostrook stomplyn voorbeeld is gebruik om die gebruik van intree, implisiete en frekwensie SM toe te lig. FEKO en AWR-MWS word vir hierdie voorbeelde gebruik. 'n Mikrostrook dubbelgevoude stomplyn filter word van die literatuur geneem en gebruik om die stelsel te evalueer. Hierdie bandstop voorbeeld het drie ontwerpsveranderlikes en daar word verwag dat drie S-parameter doelfunksies bereik word. 'n Optellings intree en implisiete SM benadering is gekies om hierdie probleem op te los. Elke iterasie is geanaliseer en die SM raamwerk haal suksesvol die spesifikasie binne vier fyn model evaluasies. Ten slotte word verbeterings aan die outomatiese raamwerk voorgelê. 'n Algemene wiskundige model word voorgestel vir eenheidstoetse, en toekomstige werk wat objek georiënteerde ontwerp voorstel word bespreek. ii

Survey Mode Effects in a Developing Country

Responses to phone surveys tend to exhibit higher rates of social desirability bias and extreme responses when compared to face-to-face surveys. Yet, studies of mode effects typically compare either representative studies that implausibly assume comparability or experimental studies that rely on convenience samples. Our study compares two national probability samples but uses matching to address comparability. We study Costa Rica, a middle-income democracy, to see whether the conventional wisdom drawn from Western Europe and North America extends to the Global South. We analyze two nationally representative surveys, one fielded by phone and one face-to-face, allowing us to compare identically worded items we placed on both surveys. We find that phone respondents exhibited more socially desirable responding and were more likely to choose negative endpoints on scalar items. This suggests that survey researchers and practitioners should carefully assess the tradeoffs in shifting modes or employing mixed modes