Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles’ impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5–58 MeV carbon ions and for protons in the energy range2–17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energiesE>~ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

A laboratory study of water ice erosion by low-energy ions

Water ice covers the surface of various objects in the outer Solar system.Within the heliopause, surface ice is constantly bombarded and sputtered by energetic particles from the solar wind and magnetospheres. We report a laboratory investigation of the sputtering yield of water ice when irradiated at 10 K by 4 keV singly (13C+, N+, O+, Ar+) and doubly charged ions (13C2+, N2+, O2+). The experimental values for the sputtering yields are in good agreement with the prediction of a theoretical model. There is no significant difference in the yield for singly and doubly charged ions. Using these yields, we estimate the rate of water ice erosion in the outer Solar system objects due to solar wind sputtering. Temperature-programmed desorption of the ice after irradiation with 13C+ and 13C2+ demonstrated the formation of 13CO and 13CO2, with 13CO being the dominant formed species.

Análise das Dimensões do Comprometimento no Setor Público da Educação: um estudo de caso com os gestores dos Campi do IFCE Limoeiro do Norte e Fortaleza - CE/Brasil

O presente trabalho tem como objetivo definir, analisar e identificar por meio de um estudo de caso, as dimensões de comprometimento organizacional: afetivas, instrumental e normativa dos gestores do campus do Limoeiro do Norte, que estão em fase de estágio probatório e dos gestores do campus Fortaleza que já passaram desse estágio, traçar um comparativo e relacionar ambos os casos. Norteado por um modelo teórico de comprometimento organizacional abordado por Meyer e Allen (1991; 1997). Comprometimento no setor público neste estudo tem-se como unidade de análise duas instituições federais de educação, ciência e tecnologia. Como os gestores são, na maioria das vezes, responsáveis pelo desenvolvimento de uma força de trabalho capaz e comprometida, sua atuação torna-se de fundamental importância no âmbito da educação, aliado a competência técnica e a vontade polí­tica de ações planejadas. De acordo com a pesquisa descritiva e quantitativa, foram aplicados questionários já testados e validados, contendo aspectos semi-estruturados, onde foi dividido em duas partes: a primeira, com seis itens, abordando as caracterí­sticas pessoais e funcionais dos gestores do IFCE de cada campus estudado, e segunda, que possui dezoito itens divididos nas três dimensões do comprometimento organizacional: afetivo, instrumental e normativo, tudo baseado na escala de mensuração do comprometimento de Meyer e Allen (1997) modelo internacionalmente aceito e validado. Os resultados obtidos na pesquisa apontaram que dos 35 gestores do campus Limoeiro do Norte o comprometimento organizacional que obteve maior média foi o afetivo. Os gestores estáveis do campus Fortaleza, também apontaram a dimensão afetiva com a maior média de comprometimento. Com isso os estudos balizam que não há uma possível relação com o fator tempo na instituição, uma vez que a maioria dos gestores do campus Fortaleza possui mais de uma década de atuação, enquanto os do campus Limoeiro do Norte, possuem menos de três anos na instituição. A maior parte dos pesquisados nos campi defendem uma forte relação na instituição, já se sentem de casa, o vínculo se estabelece pela presença de sentimentos, afeição e identificação, até mesmo pelo fato dos gestores permanecerem mais tempo no trabalho que na sua prápria casa, ele faz da organização um esteio do seu próprio lar. Conclui-se que os resultados não permitem afirmar que as dimensões do comprometimento estão relacionadas ao tempo de atuação dos gestores na instituição. / This paper aims to define, analyze and identify through a case study, the dimensions of organizational commitment: affective, continuance and normative managers campus of Castle Hayne, who are in their probationary period and the managers of Fortaleza campus who have passed this stage, draw a comparison and to relate both cases. Guided by a theoretical model of organizational commitment by Meyer and Allen (1991; 1997) approached. Commitment in the public sector in this study has as unit of analysis two federal institutions of science and technology education. As managers are, in most cases, responsible for developing a workforce capable and committed, its performance becomes very important in education, combined with technical competence and political will of planned actions. According to the descriptive and quantitative research, questionnaires were applied, tested and validated, containing aspects of semi-structured, which was divided into two parts: the first, with six items, addressing the personal and functional characteristics of the managers of each campus IFCE studied, and second, which has eighteen items divided into the three dimensions of organizational commitment: affective, continuance and normative, all based on a scale to measure the commitment of Meyer and Allen (1997) model is internationally accepted and validated. The results obtained in this research showed that the 35 managers of the Castle Hayne campus organizational commitment that was obtained more affective. Managers stable campus Fortaleza, also pointed to the affective dimension with the highest average commitment. With this guiding studies that there is a possible relationship with the time factor in the institution, since most managers campus Fortaleza has over a decade of operation, while the Castle Hayne campus, have less than three years in institution. Most of the campuses surveyed favor a strong relationship with the institution, already feel at home, the link is established by the presence of feelings, affection and identification, even by the fact that managers stay longer at work than at home, he is a mainstay of the organization of your own home. We conclude that the results do not allow us to state that the dimensions of commitment are related to time of performance of managers in the institution.

Risque de prix et décisions de production et d'exportation : le cas de l'agriculture au Québec

Cette thèse porte sur l’effet du risque de prix sur la décision des agriculteurs et les transformateurs québécois. Elle se divise en trois chapitres. Le premier chapitre revient sur la littérature. Le deuxième chapitre examine l’effet du risque de prix sur la production de trois produits, à savoir le maïs grain, la viande de porc et la viande d’agneau dans la province Québec. Le dernier chapitre est centré sur l’analyse de changement des préférences du transformateur québécois de porc pour ce qui est du choix de marché. Le premier chapitre vise à montrer l’importance de l’effet du risque du prix sur la quantité produite par les agriculteurs, tel que mis en évidence par la littérature. En effet, la littérature révèle l’importance du risque de prix à l’exportation sur le commerce international. Le deuxième chapitre est consacré à l’étude des facteurs du risque (les anticipations des prix et la volatilité des prix) dans la fonction de l’offre. Un modèle d’hétéroscédasticité conditionnelle autorégressive généralisée (GARCH) est utilisé afin de modéliser ces facteurs du risque. Les paramètres du modèle sont estimés par la méthode de l’Information Complète Maximum Vraisemblance (FIML). Les résultats empiriques montrent l’effet négatif de la volatilité du prix sur la production alors que la prévisibilité des prix a un effet positif sur la quantité produite. Comme attendu, nous constatons que l’application du programme d’assurance-stabilisation des revenus agricoles (ASRA) au Québec induit une plus importante sensibilité de l’offre par rapport au prix effectif (le prix incluant la compensation de l’ASRA) que par rapport au prix du marché. Par ailleurs, l’offre est moins sensible au prix des intrants qu’au prix de l’output. La diminution de l’aversion au risque de producteur est une autre conséquence de l’application de ce programme. En outre, l’estimation de la prime marginale relative au risque révèle que le producteur du maïs est le producteur le moins averse au risque (comparativement à celui de porc ou d’agneau). Le troisième chapitre consiste en l’analyse du changement de préférence du transformateur québécois du porc pour ce qui est du choix de marché. Nous supposons que le transformateur a la possibilité de fournir les produits sur deux marchés : étranger et local. Le modèle théorique explique l’offre relative comme étant une fonction à la fois d’anticipation relative et de volatilité relative des prix. Ainsi, ce modèle révèle que la sensibilité de l’offre relative par rapport à la volatilité relative de prix dépend de deux facteurs : d’une part, la part de l’exportation dans la production totale et d’autre part, l’élasticité de substitution entre les deux marchés. Un modèle à correction d’erreurs est utilisé lors d’estimation des paramètres du modèle. Les résultats montrent l’effet positif et significatif de l’anticipation relative du prix sur l’offre relative à court terme. Ces résultats montrent donc qu’une hausse de la volatilité du prix sur le marché étranger par rapport à celle sur le marché local entraine une baisse de l’offre relative sur le marché étranger à long terme. De plus, selon les résultats, les marchés étranger et local sont plus substituables à long terme qu’à court terme.

A teoria de Callista Roy, a nanda-i e o cuidado ao paciente prostatectomizado

Trata-se de um estudo descritivo de caso clínico, com abordagem qualitativa, o qual possui como objetivo estabelecer relações entre os diagnósticos de enfermagem da NANDA-I e os problemas de adaptação segundo o Modelo Teórico de Roy em um paciente prostatectomizado. A coleta de dados ocorreu em um hospital universitário localizado na cidade de Natal-RN, no mês de janeiro de 2011, por meio de um roteiro de entrevista e exame físico. Os diagnósticos que apresentaram relações entre a NANDA-I e o Modelo de Roy foram: dor, ansiedade, constipação, sono, atividade, volume de líquido e infecção. Conclui-se que grande parte dos problemas adaptativos segundo o Modelo de Roy, manifestados pelos pacientes no pós-operatório de prostatectomia, possuem semelhança com os diagnósticos da NANDA-I

Programa de aquisição de alimentos (2003-2010): avaliação da implementação pela CONAB no Rio Grande do Norte

This thesis aimed to evaluate the implementation of the Food Acquisition Program(PAA) through CONAB RN in the period of 2003-2010 with the perception of all agents involved in the implementation of the government program.For the methodological trajectory it was adopted a descriptive bibliographical and documentary approach with triangular qualitative and quantitative, also called evaluative research.The theoretical model was supported by the authors Draibe (2001), Aguilar and Ander-Egg (1994) and Silva(2001), among others, that focused on family farming and evaluation of implementation of public policy having as a category of analysis the size implementation of policy and the latter divided into 10 theoretical dimensions.The universe consisted of three groups: the first were the managers and technicians from CONAB(RN and Brasilia), totaling 15 subjects. The second group was of associations/cooperatives that participated in the programin 2010, totaling a sample in each access of 15 representatives. The third group of subjects totaled with 309 representatives of governmental and non-governmental organizations that received donations of food for the same period. Semi-structured interviews and forms were adopted as instruments of data collection.The data were processed qualitatively by the analysis of content (interviews and documents) and quantitatively by means of statistical tests that allowed inferences and adoption of frequencies. Among the key find ingests that the program is not standing as a structure supported by planning. The interests of the performers do not necessarily converge with the objectives of the Food Acquisition Program (PAA). A shockof goals was identified (within the same program) when comparingthe financial agent (Ministry of Rural Development and of Social Development and Fight Against Hunger Ministry r) and the executor, CONAB/RN. Within the assessed dimensions, the most fragileis the sub-managerial decision-making and Organizational Environment and internal assessment, still deserves attention the sizeof logistical and operational Subsystem, as this also proved weak.The focusin the quest toexpand thequantificationof the resultsof theFood Acquisition Program (PAA)by CONAB/RN does forget a quality management focused on what really should be:the compliance with the institutional objectives of the government program.Finally, the perspective for the traded implementation should be re-examined because excessive discretion by managers along with technical staff has characterized there al role of the Food Acquisition Program (PAA) as public policy. We conclude that the implementation model, which apparently aggregates values to the benefitted citizens, has weakened the context of work on family farms having the management model of the implementation process be reviewed by the Federal Government and point too ther paths, which have as a guide line the emancipation and developmentof the field or in the field andat the same time enables the reduction of nutritional deficiency of beneficiaries in a balanced and coherent way

The physical classroom environment : roles, conceptions, and preferences

The problem addressed in this thesis is that a considerable proportion of students around the world attend school in inadequate facilities, which is detrimental for the students’ learning outcome. The overall objective in this thesis is to develop a methodology, with a novel approach to involve teachers, to generate a valuable basis for decisions regarding design and improvement of physical school environment, based on the expressed needs for a specific school, municipality, or district as well as evidence from existing research. Three studies have been conducted to fulfil the objective: (1) a systematic literature review and development of a theoretical model for analysing the role of the physical environment in schools; (2) semi structured interviews with teachers to get their conceptions of the physical school environment; (3) a stated preference study with experimental design as an online survey. Wordings from the transcripts from the interview study were used when designing the survey form. The aim of the stated preference study was to examine the usability of the method when applied in this new context of physical school environment. The result is the methodology with a mixed method chain where the first step involves a broad investigation of the specific circumstances and conceptions for the specific school, municipality, or district. The second step is to use the developed theoretical model and results from the literature study to analyse the results from the first step and transform them in to a format that fits the design of a stated preference study. The final step is a refined version of the procedure of the performed stated preference study.

Supply Chain Adaptation of Finnish Companies in Chinese Institutional Environment

Within the last few decades of operations and supply chain management, the field has seen the rise of so called best practices, methods that will help supply chains obtain their business goals and gain a competitive edge. These methods were thought to be universal. This however is not always the case, as the surrounding business environment could have a significant impact on what will be effective in gaining competitive edge. Contingency theory states that the success of a supply chain is determined by both internal capabilities, as well as external context aligning. This creates a strategic fit, which is a major determinant of success. In order for supply chains to reach this strategic fit, they must adapt. As China has seen rapid growth and over the last few decades become one of the major economies of the world, Western companies have tried to establish themselves there, only to find that the Chinese market is extremely difficult to operate in. The aim of this thesis was to investigate from contingency theory perspective, what are the institutional factors that affect supply chain management of Finnish companies operating in China, and how do Finnish companies adapt their supply chains to better fit the Chinese institutional environment. A theoretical model was created for this thesis, in which supply chains possess resources, which can be combined in a meaningful manner to create capabilities. Both resources and capabilities are affected by the surrounding institutional environment, which forces supply chains to adapt in order to find a better strategic fit. A total of six Finnish managers from three large and three small companies operating in China were interviewed. The results indicated that the Chinese business environment is significantly different, than that of Finland or Western countries in general. Three institutional factors were identified: Confucian though, fast-paced business environment, and managing labor force. These three institutional factors made the relationship and delivery capabilities particularly important, as well as human resources, reputation, physical resources and technological resources. In conclusion, it was discovered that the Chinese institutional environment is heavily affected by Confucian thought, as well as the rapid market growth. These are the two most important institutional factors that shape the Chinese market. If supply chains wish to be successful in China, adaptation regarding these two institutional factors should yield good results.

Validation of the self-regulated online learning questionnaire

Abstract The number of students engaged in Massive Open Online Courses (MOOCs) is increasing rapidly. Due to the autonomy of students in this type of education, students in MOOCs are required to regulate their learning to a greater extent than students in traditional, face-to-face education. However, there is no questionnaire available suited for this online context that measures all aspects of self-regulated learning (SRL). In this study, such a questionnaire is developed based on existing SRL questionnaires. This is the self-regulated online learning ques- tionnaire. Exploratory factor analysis (EFA) on the first dataset led to a set of scales differing from those theoretically defined beforehand. Confirmatory factor analysis (CFA) was conducted on a second dataset to compare the fit of the theoretical model and the exploratively obtained model. The exploratively obtained model provided much better fit to the data than the theoretical model. All models under investigation provided better fit when excluding the task strategies scale and when merging the scales measuring metacognitive activities. From the results of the EFA and the CFA it can be concluded that further development of the questionnaire is necessary.

Fatores que influenciam a aceitação de práticas avançadas de gestão de segurança da informação: um estudo com gestores públicos estaduais no Brasil

This study examines the factors that influence public managers in the adoption of advanced practices related to Information Security Management. This research used, as the basis of assertions, Security Standard ISO 27001:2005 and theoretical model based on TAM (Technology Acceptance Model) from Venkatesh and Davis (2000). The method adopted was field research of national scope with participation of eighty public administrators from states of Brazil, all of them managers and planners of state governments. The approach was quantitative and research methods were descriptive statistics, factor analysis and multiple linear regression for data analysis. The survey results showed correlation between the constructs of the TAM model (ease of use, perceptions of value, attitude and intention to use) and agreement with the assertions made in accordance with ISO 27001, showing that these factors influence the managers in adoption of such practices. On the other independent variables of the model (organizational profile, demographic profile and managers behavior) no significant correlation was identified with the assertions of the same standard, witch means the need for expansion researches using such constructs. It is hoped that this study may contribute positively to the progress on discussions about Information Security Management, Adoption of Safety Standards and Technology Acceptance Model

Gestão colegiada da cadeia produtiva da cajucultura: o papel do comitê gestor no Rio Grande do Norte à luz do desenvolvimento regional sustentável

The theme of this dissertation is the collegiate management in the cashew cultivation s productive chain by the reading of the Managerial Committee s role in accordance with Sustainable Regional Development. The research had as aim to reveal the way as Managerial Committee s members of cashew cultivation s productive chain interpret the economic, social and environmental dimensions to the sustainability of entrepreneurships, using as interpretative base Sachs (2004) theoretical model. The theoretical reference is based in precepts of Solidarity Economy as a strategy to the Sustainable Regional Development. To reach this aim was done a case study, based in analysis of contents and semi-structured interviews with the solidarities economic entrepreneurships that integrate the Committee and with the group of Entities of Support and Fomentation responsible for formulating and conducting actions in favour of development of the chain. The research permitted to conclude that the economic, mainly, and social dimension, secondly, to super-impose the environmental dimension. The actions in favour of the chain are yet restricted and with low effectiveness when interpreted, in an integrated way, by a side, by the informers of this research and, by another side, in accordance with precepts of sustainable development

Evaluating a School Community Linked Physical Activity Intervention Programme: a Multi-level Analysis.

Previous research has highlighted the importance of positive physical activity (PA) behaviors during childhood to promote sustained active lifestyles throughout the lifespan (Telama et al. 2005; 2014). It is in this context that the role of schools and teachers in facilitating PA education is promoted. Research suggests that teachers play an important role in the attitudes of children towards PA (Figley 1985) and schools may be an efficient vehicle for PA provision and promotion (McGinnis, Kanner and DeGraw, 1991; Wechsler, Deveraux, Davis and Collins, 2000). Yet despite consensus that schools represent an ideal setting from which to ‘reach’ young people (Department of Health and Human Services, UK, 2012) there remains conceptual (e.g. multi-component intervention) and methodological (e.g. duration, intensity, family involvement) ambiguity regarding the mechanisms of change claimed by PA intervention programmes. This may, in part, contribute to research findings that suggest that PA interventions have had limited impact on children’s overall activity levels and thereby limited impact in reducing children’s metabolic health (Metcalf, Henley & Wilkin, 2012). A marked criticism of the health promotion field has been the focus on behavioural change while failing to acknowledge the impact of context in influencing health outcomes (Golden & Earp, 2011). For years, the trans-theoretical model of behaviour change has been ‘the dominant model for health behaviour change’ (Armitage, 2009); this model focusses primarily on the individual and the psychology of the change process. Arguably, this model is limited by the individual’s decision-making ability and degree of self-efficacy in order to achieve sustained behavioural change and does not take account of external factors that may hinder their ability to realise change. Similar to the trans-theoretical model, socio-ecological models identify the individual at the focal point of change but also emphasises the importance of connecting multiple impacting variables, in particular, the connections between the social environment, the physical environment and public policy in facilitating behavioural change (REF). In this research, a social-ecological framework was used to connect the ways a PA intervention programme had an impact (or not) on participants, and to make explicit the foundational features of the programme that facilitated positive change. In this study, we examined the evaluation of a multi-agency approach to a PA intervention programme which aimed to increase physical activity, and awareness of the importance of physical activity to key stage 2 (age 7-12) pupils in three UK primary schools. The agencies involved were the local health authority, a community based charitable organisation, a local health administrative agency, and the city school district. In examining the impact of the intervention, we adopted a process evaluation model in order to better understand the mechanisms and context that facilitated change. Therefore, the aim of this evaluation was to describe the provision, process and impact of the intervention by 1) assessing changes in physical activity levels 2) assessing changes in the student’s attitudes towards physical activity, 3) examining student’s perceptions of the child size fitness equipment in school and their likelihood of using the equipment outside of school and 4) exploring staff perceptions, specifically the challenges and benefits, of facilitating equipment based exercise sessions in the school environment. Methodology, Methods, Research Instruments or Sources Used Evaluation of the intervention was designed as a matched-control study and was undertaken over a seven-month period. The school-based intervention involved 3 intervention schools (n =436; 224 boys) and one control school (n=123; 70 boys) in a low socioeconomic and multicultural urban setting. The PA intervention was separated into two phases: a motivation DVD and 10 days of circuit based exercise sessions (Phase 1) followed by a maintenance phase (Phase 2) that incorporated a PA reward program and the use of specialist kid’s gym equipment located at each school for a period of 4 wk. Outcome measures were measured at baseline (January) and endpoint (July; end of academic school year) using reliable and valid self-report measures. The children’s attitudes towards PA were assessed using the Children’s Attitudes towards Physical Activity (CATPA) questionnaire. The Physical Activity Questionnaire for Children (PAQ-C), a 7-day recall questionnaire, was used to assess PA levels over a school week. A standardised test battery (Fitnessgram®) was used to assess cardiovascular fitness, body composition, muscular strength and endurance, and flexibility. After the 4 wk period, similar kid’s equipment was available for general access at local community facilities. The control school did not receive any of the interventions. All physical fitness tests and PA questionnaires were administered and collected prior to the start of the intervention (January) and following the intervention period (July) by an independent evaluation team. Evaluation testing took place at the individual schools over 2-3 consecutive days (depending on the number of children to be tested at the school). Staff (n=19) and student perceptions (n = 436) of the child sized fitness equipment were assessed via questionnaires post-intervention. Students completed a questionnaire to assess enjoyment, usage, ease of use and equipment assess and usage in the community. A questionnaire assessed staff perceptions on the delivery of the exercise sessions, classroom engagement and student perceptions. Conclusions, Expected Outcomes or Findings Findings showed that both the intervention (16.4%) and control groups increased their PAQ-C score by post-intervention (p < 0.05); with the intervention (17.8%) and control (21.3%) boys showing the greatest increase in physical activity levels. At post-intervention, there was a 5.5% decline in the intervention girls’ attitudes toward PA in the aesthetic subdomains (p = 0.009); whereas the control boys had an increase in positive attitudes in the health domain (p = 0.003). No significant differences in attitudes towards physical activity were observed in any other domain for either group at post-intervention (p > 0.05). The results of the equipment questionnaire, 96% of the children stated they enjoyed using the equipment and would like to use the equipment again in the future; however at post-intervention only 27% reported using the equipment outside of school in the last 7 days. Students identified the ski walker (34%) and cycle (32%) as their favorite pieces of equipment; with the single joint exercises such as leg extension and bicep/tricep machine (<3%) as their least favorite. Key themes from staff were that the equipment sessions were enjoyable, a novel activity, children felt very grown-up, and the activity was linked to a real fitness experience. They also expressed the need for more support to deliver the sessions and more time required for each session. Findings from this study suggest that a more integrated approach within the various agencies is required, particularly more support to increase teachers pedagogical content knowledge in physical activity instruction which is age appropriate. Future recommendations for successful implementation include sufficient time period for all students to access and engage with the equipment; increased access and marketing of facilities to parents within the local community, and professional teacher support strategies to facilitate the exercise sessions.

Estudo do consumo energético associado ao processo de cozedura na indústria cerâmica

O presente trabalho realizou-se no âmbito do Projeto Galp 20-2020 implementado na empresa Sanindusa, em parceira com a Universidade de Aveiro. Como principal objetivo pretendia-se estudar o consumo de energia durante o processo de cozedura das peças cerâmicas com o intuito de avaliar a viabilidade da substituição do refratário existente na empresa. Uma vez que esta medida implicaria um tempo de retorno do investimento demasiado elevado, optou-se por estudar o consumo de energia associado a uma placa horizontal, de massa unitária, de qualquer tipo de material refratário. Para tal, foi desenvolvido um Modelo Teórico capaz de calcular o calor absorvido por uma placa de refratário ao longo de todo o percurso dentro do Forno Túnel 2, existente na empresa e utilizado no processo de produção das peças cerâmicas. Através deste estudo foi possível concluir que o Modelo Teórico é bastante útil na medida em que permite a criação de vários cenários, através da alteração de diversas variáveis, permitindo conhecer qual o impacto de cada uma no consumo de energia neste equipamento. Como trabalho futuro propõe-se o desenvolvimento do Modelo Teórico apresentado para o estudo da transferência de calor bidimensional. Esta melhoria permitiria analisar o consumo de energia associado a diferentes formas de material refratário utilizado no processo de cozedura de peças cerâmicas (o que não é possível quando se aplica o conceito de transferência de calor unidimensional).

A satisfação e a intenção de continuidade de uso em servços de e-learning:validação empírica de um modelo aplicado no serviço público

The present study aims to investigate the constructs of Technological Readiness Index (TRI) and the Expectancy Disconfirmation Theory (EDT) as determinants of satisfaction and continuance intention use in e-learning services. Is proposed a theoretical model that seeks to measure the phenomenon suited to the needs of public organizations that offer distance learning course with the use of virtual platforms for employees. The research was conducted from a quantitative analytical approach, via online survey in a sample of 343 employees of 2 public organizations in RN who have had e-learning experience. The strategy of data analysis used multivariate analysis techniques, including structural equation modeling (SEM), operationalized by AMOS© software. The results showed that quality, quality disconfirmation, value and value disconfirmation positively impact on satisfaction, as well as disconfirmation usability, innovativeness and optimism. Likewise, satisfaction proved to be decisive for the purpose of continuance intention use. In addition, technological readiness and performance are strongly related. Based on the structural model found by the study, public organizations can implement e-learning services for employees focusing on improving learning and improving skills practiced in the organizational environment

Computer simulations of soft particles in flow

Understanding the dynamics of blood cells is a crucial element to discover biological mechanisms, to develop new efficient drugs, design sophisticated microfluidic devices, for diagnostics. In this work, we focus on the dynamics of red blood cells in microvascular flow. Microvascular blood flow resistance has a strong impact on cardiovascular function and tissue perfusion. The flow resistance in microcirculation is governed by flow behavior of blood through a complex network of vessels, where the distribution of red blood cells across vessel cross-sections may be significantly distorted at vessel bifurcations and junctions. We investigate the development of blood flow and its resistance starting from a dispersed configuration of red blood cells in simulations for different hematocrits, flow rates, vessel diameters, and aggregation interactions between red blood cells. Initially dispersed red blood cells migrate toward the vessel center leading to the formation of a cell-free layer near the wall and to a decrease of the flow resistance. The development of cell-free layer appears to be nearly universal when scaled with a characteristic shear rate of the flow, which allows an estimation of the length of a vessel required for full flow development, $l_c \approx 25D$, with vessel diameter $D$. Thus, the potential effect of red blood cell dispersion at vessel bifurcations and junctions on the flow resistance may be significant in vessels which are shorter or comparable to the length $l_c$. The presence of aggregation interactions between red blood cells lead in general to a reduction of blood flow resistance. The development of the cell-free layer thickness looks similar for both cases with and without aggregation interactions. Although, attractive interactions result in a larger cell-free layer plateau values. However, because the aggregation forces are short-ranged at high enough shear rates ($\bar{\dot{\gamma}} \gtrsim 50~\text{s}^{-1}$) aggregation of red blood cells does not bring a significant change to the blood flow properties. Also, we develop a simple theoretical model which is able to describe the converged cell-free-layer thickness with respect to flow rate assuming steady-state flow. The model is based on the balance between a lift force on red blood cells due to cell-wall hydrodynamic interactions and shear-induced effective pressure due to cell-cell interactions in flow. We expect that these results can also be used to better understand the flow behavior of other suspensions of deformable particles such as vesicles, capsules, and cells. Finally, we investigate segregation phenomena in blood as a two-component suspension under Poiseuille flow, consisting of red blood cells and target cells. The spatial distribution of particles in blood flow is very important. For example, in case of nanoparticle drug delivery, the particles need to come closer to microvessel walls, in order to adhere and bring the drug to a target position within the microvasculature. Here we consider that segregation can be described as a competition between shear-induced diffusion and the lift force that pushes every soft particle in a flow away from the wall. In order to investigate the segregation, on one hand, we have 2D DPD simulations of red blood cells and target cell of different sizes, on the other hand the Fokker-Planck equation for steady state. For the equation we measure force profile, particle distribution and diffusion constant across the channel. We compare simulation results with those from the Fokker-Planck equation and find a very good correspondence between the two approaches. Moreover, we investigate the diffusion behavior of target particles for different hematocrit values and shear rates. Our simulation results indicate that diffusion constant increases with increasing hematocrit and depends linearly on shear rate. The third part of the study describes development of a simulation model of complex vascular geometries. The development of the model is important to reproduce vascular systems of small pieces of tissues which might be gotten from MRI or microscope images. The simulation model of the complex vascular systems might be divided into three parts: modeling the geometry, developing in- and outflow boundary conditions, and simulation domain decomposition for an efficient computation. We have found that for the in- and outflow boundary conditions it is better to use the SDPD fluid than DPD one because of the density fluctuations along the channel of the latter. During the flow in a straight channel, it is difficult to control the density of the DPD fluid. However, the SDPD fluid has not that shortcoming even in more complex channels with many branches and in- and outflows because the force acting on particles is calculated also depending on the local density of the fluid.