Advances in single-shot, dry drilling of composite/metal stacks

Carbon fibre reinforced polymers (CFRP) are increasingly being used in the aerospace, automotive and defence industry due to their high specific stiffness and good corrosion resistance. In a modern aircraft, 50-60% of its structure is made up of CFRP material while the remainder is mostly a combination of metallic alloys (typically aluminium or titanium alloys). Mechanical fastening (bolting or riveting) of CFRP and metallic components has thus created a pressing requirement of drilling several thousand holes per aircraft. Drilling of stacks in a single-shot not only saves time, but also ensures proper alignment when fasteners are inserted, achieving tighter geometric tolerances. However, this requirement poses formidable manufacturing challenges due to the fundamental differences in the material properties of CFRP and metals e.g. a drill bit entering into the stack encounters brittle and abrasive CFRP material as well as the plastic behaviour of the metallic alloy, making the drilling process highly non-linear.

Over the past few years substantial efforts have been made in this direction and majority of the research has tried to establish links between how the process parameters (feed, depth of cut, cutting speed), tooling (geometry, material and coating) and the wear of the cutting tool affect the hole quality. Similarly, multitudes of investigations have been conducted to determine the effects of non-traditional drilling methods (orbital, helical and vibration assisted drilling), cutting zone temperatures and efficiency of chip extraction on the hole quality and rate of tool wear during single shot drilling of CFRP/alloy stacks.

In a timely effort, this paper aims at reviewing the manufacturing challenges and barriers faced when drilling CFRP/alloy stacks and to summarise various factors influencing the drilling process while detailing the advances made in this fertile research area of single-shot drilling of stack materials. A survey of the key challenges associated with avoiding workpiece damage and the effect these challenges have on tool design and process optimisation is presented. An in depth critique of suitable hole making methods and their aptness for commercialisation follows. The paper concludes by summarising the future work required to achieve repeatable, high quality single shot drilled holes in CFRP/alloy stacks.

Measuring energy footprint of software features

Abstract—With the proliferation of Software systems and the rise of paradigms such the Internet of Things, Cyber- Physical Systems and Smart Cities to name a few, the energy consumed by software applications is emerging as a major concern. Hence, it has become vital that software engineers have a better understanding of the energy consumed by the code they write. At software level, work so far has focused on measuring the energy consumption at function and application level. In this paper, we propose a novel approach to measure energy consumption at a feature level, cross-cutting multiple functions, classes and systems. We argue the importance of such measurement and the new insight it provides to non-traditional stakeholders such as service providers. We then demonstrate, using an experiment, how the measurement can be done with a combination of tools, namely our program slicing tool (PORBS) and energy measurement tool (Jolinar).

Common Environment for Undergraduate Computer Programming

We present an Integrated Environment suitable for learning and teaching computer programming which is designed for both students of specialised Computer Science courses, and also non-specialist students such as those following Liberal Arts. The environment is rich enough to allow exploration of concepts from robotics, artificial intelligence, social science, and philosophy as well as the specialist areas of operating systems and the various computer programming paradigms.

Modelo de valoración ajustado a la evolución del riesgo crediticio para carteras colectivas que invierten en títulos valores no tradicionales en la comisionista global Securities Colombia de la Ciudad de Medellín

Con los comportamientos del mercado financiero, las comisionistas de bolsa deben tener un modelo de valoración ajustado a la evolución del riesgo crediticio para las inversiones en títulos valores no tradicionales y de esta manera cumplir con los requerimientos emitidos por la Superintendencia Financiera de Colombia. En particular, se diseña el modelo sugerido por el regulador para la comisionista Global Securities de la ciudad de Medellín, para la cartera colectiva Credit Opportunities Fund - Compartimiento Facturas. El estudio de tipo descriptivo, analiza y diseña a partir del método CreditMetrics desarrollado por J.P Morgan, una valoración completa de la cartera teniendo en cuenta las pérdidas y ganancias por modificaciones de calidad crediticia.

O papel do bilinguismo no processo de difusão das línguas

O presente estudo propõe-se estudar as representações de alunos bilingues e não bilingues acerca do papel do bilinguismo no processo de difusão das línguas. Para dar resposta a este objetivo, desenhámos um projeto de intervenção que compreendeu a utilização de duas técnicas de recolha de dados: a entrevista e o inquérito por questionário, que implementámos a alunos do distrito de Aveiro. Os resultados obtidos permitiram concluir que, de forma geral, os alunos consideram que os falantes são os principais responsáveis pela difusão das línguas, contribuindo para o aumento de utilizadores da mesma e, portanto, para a sua expansão.

"They're my kryptonite but they also empower me": The double-edged sword of familismo

The objective of this study is to examine the relations of familismo to academic functioning and mental health among non-citizen Latina/o college students. The study utilizes both quantitative self-report surveys to explore attitudinal family obligations, and qualitative interviews to explore behavioral family obligations. One hundred and eighty citizen students (M = 21.30, SD = 2.92) and 84 non-citizen students (M = 21.13, SD = 2.98) completed surveys. Correlational analyses found that family obligation attitudes were linked to academic emotional engagement for non-citizen students only (r = .305, p = .005, n = 84). Cluster analyses revealed risk, resilience, and protected clusters from stress and family obligation groupings. Twenty-one non-citizen students also completed interviews. Narrative analysis of the interviews revealed that family obligation behaviors may be linked to motivation and stress. Overall, this study illustrates the complex nature of family obligations and achievement in the lives of non-citizen Latina/o college students.

The introduction of e-learning in European universities: models and strategies

The aim of this paper is to present the models and the strategies of adoption of e-learning in a group of European universities, most of them located in the regions called “the four motors of Europe” (Baden-Württenberg, Catalunya, Lombardy and Rhône-Alpes) and in Switzerland. Our analysis focuses on four dimensions: the rationale behind the introduction of e-learning, the organisation of the activities and, in particular, the existence of a university centre for e-learning, the type of activities, and, finally, the type of public reached by e-learning. The majority of campus universities in our sample introduced e-learning to improve the quality of education of their students and, for the most part, as a support for existing courses. Some of the campus universities went even further insofar as they have introduced some online courses into their curricula. This has led to forms of cooperation where different universities share some of their courses. Finally, a small number of campus universities have included as part of their educational offer full distance degree programs which can be attended also by non residential students. The above cases show that there is no general move from campus universities towards distance education, but rather a more selective behaviour. Thus we conclude that e-learning, although it is undoubtedly spreading in both distance and presence universities, is not yet bringing fundamental changes in the institutions themselves. E-learning is at the moment integrated into the existing organization and educational offer. (DIPF/Orig.)

Exploiting Nested Parallelism on Heterogeneous Processors

Heterogeneous computing systems have become common in modern processor architectures. These systems, such as those released by AMD, Intel, and Nvidia, include both CPU and GPU cores on a single die available with reduced communication overhead compared to their discrete predecessors. Currently, discrete CPU/GPU systems are limited, requiring larger, regular, highly-parallel workloads to overcome the communication costs of the system. Without the traditional communication delay assumed between GPUs and CPUs, we believe non-traditional workloads could be targeted for GPU execution. Specifically, this thesis focuses on the execution model of nested parallel workloads on heterogeneous systems. We have designed a simulation flow which utilizes widely used CPU and GPU simulators to model heterogeneous computing architectures. We then applied this simulator to non-traditional GPU workloads using different execution models. We also have proposed a new execution model for nested parallelism allowing users to exploit these heterogeneous systems to reduce execution time.

Solvency considerations in the gamma-omega surplus model

Ce mémoire de maîtrise traite de la théorie de la ruine, et plus spécialement des modèles actuariels avec surplus dans lesquels sont versés des dividendes. Nous étudions en détail un modèle appelé modèle gamma-omega, qui permet de jouer sur les moments de paiement de dividendes ainsi que sur une ruine non-standard de la compagnie. Plusieurs extensions de la littérature sont faites, motivées par des considérations liées à la solvabilité. La première consiste à adapter des résultats d’un article de 2011 à un nouveau modèle modifié grâce à l’ajout d’une contrainte de solvabilité. La seconde, plus conséquente, consiste à démontrer l’optimalité d’une stratégie de barrière pour le paiement des dividendes dans le modèle gamma-omega. La troisième concerne l’adaptation d’un théorème de 2003 sur l’optimalité des barrières en cas de contrainte de solvabilité, qui n’était pas démontré dans le cas des dividendes périodiques. Nous donnons aussi les résultats analogues à l’article de 2011 en cas de barrière sous la contrainte de solvabilité. Enfin, la dernière concerne deux différentes approches à adopter en cas de passage sous le seuil de ruine. Une liquidation forcée du surplus est mise en place dans un premier cas, en parallèle d’une liquidation à la première opportunité en cas de mauvaises prévisions de dividendes. Un processus d’injection de capital est expérimenté dans le deuxième cas. Nous étudions l’impact de ces solutions sur le montant des dividendes espérés. Des illustrations numériques sont proposées pour chaque section, lorsque cela s’avère pertinent.

Trapping phosphorus (III) into polyoxometalates: synthesis, characterisation and electronic behaviour study

The introduction of electronically-active heteroanions into polyoxometalates (POMs) is one of the emerging topics in this field. The novel clusters have shown unprecedented intramolecular electron-transfer features that can be directly mediated by the incorporated heteroanions. In this thesis, we will focus on the study of phosphite (HPO32-) as new non-traditional heteroanions, discover HPO32- templated nanostructures, investigate their electronic behaviours as well as understand the self-assembly process of HPO32--templated species. The thesis starts with incorporating HPO32- into POM cages. The feasibility of this work was illustrated by the successful trapping of HPO32- into a “Trojan Horse” type {W18O56} nanocage. The reactivity of embedded {HPO3} was fully studied, showing the cluster undergoes a structural rearrangement in solution whereby the {HPO3} moieties dimerise to form a weakly interacting (O3PH···HPO3) moiety. In the crystalline state a temperature-dependent intramolecular redox reaction and structural rearrangement occurs. This rearrangement appears to proceed via an intermediate containing two different templates, a pyramidal {HPO3} and a tetrahedral {PO4} moiety. {HPO3} templated POM cages were then vigorously expanded and led to the isolation of five either fully oxidised or mixed-valence clusters trapped with mono-, di-, or tri- {HPO3}. Interestingly, an intriguing 3D honeycomb-like host-guest structure was also synthesised. The porous framework was self-aggregated by a tri-phopshite anion templated {W21} cluster with a {VO4} templated Wells-Dawson type {W18} acting as a guest species within the hexagonal channels. Based on this work, we further extended the templating anions to two different redox-active heteroanions, and discovered a unique mixed-heteroatom templated system built by pairing redox-active {HPIIIO3} with {TeO3}, {SeO3} or {AsO3}. Two molecular systems were developed, ie. “Trojan Horse” type [W18O56(HPO3)0.8(SeO3)1.2(H2O)2]8- and cross-shaped [H4P4X4W64O224]32-/36-, where X=TeIV, SeIV, AsIII. In the case of {W18(HPO3)0.8(SeO3)1.2}, the compound is found to be a mixture of heteroleptic {W18(HPO3)(SeO3)} and homoleptic {W18(SeO3)2} and {W18(HPO3)2}, identified by single crystal x-ray diffraction, NMR as well as high resolution mass spectrometry. The cluster exhibited similar temperature-dependent electronic features to “Trojan Horse” type {W18(HPO3)2O56}. However, due to the intrinsic reactivity difference between {HPO3} and {SeO3}, the thermal treatment leads to the formation of an unusual species [W18O55(PO4)(SeO3)]5-, in which {HPO3} was fully oxidised to {PO4} within the cage, whereas and lone-pair-containing {SeO3} heteroanions were kept intact inside the shell. This finding is extremely interesting, as it demonstrated that multiple and independent intramolecular electronic performance can be achieved by the coexistence of distinct heteroatoms within a single molecule. On the other hand, the cross-shaped [H4P4X4W64O224]32-/36- were constructed by four {W15(HPO3)(XO3)} building units linked by four {WO6} octahedra. Each building unit traps two different heteroatoms. It is interesting to note that the mixed heteroatom species show self-sorting, with a highly selective positional preference. Smaller ionic sized {HPO3} are self-organised into the uncapped side of {W15} cavity, whereas closed side are occupied by larger heteroatoms, which is surprisingly opposed to steric hindrance. Density functional theory (DFT) calculations are currently underway to have a full understanding of the preference of heteroatom substitutions. This series of clusters is of great interest in terms of achieving single molecule-based heteroatom-dependent multiple levels of electron transfer. It has opened a new way to design and synthesise POMs with higher diversity of electrical states, which may lead to a new type of Q-bits for quantum computing. The third chapter is focused on developing polyoxotungstate building blocks templated by {HPO3}. A series of building blocks, {W15O48(HPO3)2}, {W9O30(HPO3)} {W12O40(HPO3)2} and hexagonal {W6O18(HPO3)} have been obtained. The first four building blocks have been reported with {SeO3} and/or {TeO3} heteroanions. This result demonstrates {HPO3} has a similar reactivity as {SeO3} and {TeO3}, therefore studying the self-assembly of {HPO3}-based building blocks would be helpful to have a general understanding of pyramidal heteroatom-based molecular systems. The hexagonal {W6O18(HPO3)} is observed for the first time in polyoxotungstates, showing some of reactivity difference between {HPO3} and {SeO3} and {TeO3}. Furthermore, inorganic salts and pH values have some directing influence on the formation and transformation of various building blocks, resulting in the discovery of a family of {HPO3}-based clusters with nuclearity ranging from {W29} to {W106}. High resolution mass spectrometry was also carried out to investigate the cluster solution behaviour and also gain information of building block speciation. It is found that some clusters experienced decomposition, which gives rise to potential building blocks accountable for the self-assembly.

Representações de alunos do 3º ciclo face à integração de alunos com trissomia 21

Dissertação de Mestrado apresentada no Instituto Superior de Psicologia Aplicada para obtenção de grau de Mestre na especialidade de Psicologia Educacional

How teachers' perceptions affect the academic and language assessment of immigrant children

Recent research evidences inconsistencies in teachers' practice regarding skills assessment of L2 students. Scientific evidence supports that less experienced teachers have lower orientation toward multiple task-tests for non-native students. Research questions: Whether school teachers as having different teaching training and unequal teaching experience with non-native students perceive differently a four-skills scale. Purpose of the study: This study intends to analyse the importance degree between the four skills/tasks: reading, writing, speaking and listening, in the perspective of school teachers. Method: 77 teachers, aged 32-62, with (and without) experience in teaching and adapting materials for immigrant students, divided into six groups according to their scientific domain. Assessment tools included a scale for judgement of four academic tasks adapted from the original “Inventory of Undergraduate and Graduate Level: Reading, Writing, Speaking and Listening Tasks (Rosenfeld, Leung & Ottman, 2001). Main Findings: 1) different degrees of importance attributed by teachers on tasks that should be included in academic and language test for immigrant students; 2) perceptions of teachers are determined by predictors in this order: scientific domain, experience with multicultural classes and lower prediction from teaching service and age; 3) different results between american and portuguese samples answering the same questionnaire.

Nutrición animal en sistemas tropicales: uso de residuos agrícolas en la producción animal

El aumento mundial en la demanda de alimentos, especialmente proteína, plantea la necesidad de aplicar estrategias más eficientes y sostenibles de alimentación animal. La capacidad de los rumiantes de utilizar eficientemente la fibra hace posible aprovechar subproductos y residuos agrícolas provenientes de cultivos tropicales como la palma aceitera, banano y mango, los cuales también aportan energía y proteína. Al respecto, Cuenca et al. (2015) mencionan que la harina de almendra de palma posee un valor aproximado de 14.8% de proteína cruda y 8.9% de grasa. Por su parte, Silva et al. (2014) reportan que el uso de harina integral de mango reduce las emisiones de gas y aumenta el contenido de grasa en la leche de cabras Saanen, aunque concentraciones crecientes disminuyen linealmente el volumen de producción. En cuanto a la digestibilidad de estos productos, DiLorenzo et al. (datos no publicados) mencionan que la cascara y fruto maduro del banano presentan una alta digestibilidad in vitro de la materia orgánica (90.45%), superior a la de otros productos del banano, kikuyo y palmiste. Un alimento menos tradicional, el ensilado de pez diablo (EPD) fue incluido en diferentes niveles por Tejeda-Arroyo et al. (2015), en dietas de corderos en crecimiento, obteniendo ganancias de peso de 211.5 g/día (18% EPD) y conversión alimenticia de 6.6 y 6.4 kilogramo de alimento por kilogramo de ganancia de peso (27% EPD y 9% EPD). Se requiere avanzar en la investigación del potencial nutritivo de estos y otros alimentos no tradicionales, así como de las técnicas adecuadas para su mejor utilización, almacenamiento y transporte. El uso de estos subproductos podría reducir los costos de producción y contribuir a disminuir el impacto ambiental de las actividades agrícolas y ganaderas.

A NARRATIVE CASE STUDY EXAMINING THE EXPEREINCES OF MEN TEACHING SPECIAL EDUCATION IN THE ELEMENTARY GRADES

Over the past several decades, the landscape of the workplace has changed in many industrialized nations. In the United States this time period has seen the outright elimination or outsourcing of well-paying “blue collar” jobs. The workforce continues to evolve, change, and become more global, and men and women are making nontraditional occupational decisions, whether by choice or necessity. The traditional views of men and women have begun to shift. However, gender assumptions about masculinity have failed to keep pace with the shift. There are approximately 1.8 million elementary grade level teachers in United States public schools; of these, a mere 9% are male. The paucity of male teachers in the elementary grades has been a concern for many years. According to the Bureau of Labor Statistics, roughly 86% of all special education teachers are female. In 2012, 86.2% of all special education teachers were female, and by the following year, the number had dropped to 80.4%. The evidence indicates that more men are embarking on nontraditional career paths. Despite theses changes there is minimal research looking at the experiences of men working as special education teachers My goal in this study was to obtain a better understanding of the influences on and the process by which men make the decision to pursuing a career teaching special education in the elementary grades. The study utilized social role theory (Eagly, 1987), and Stead’s (2014) social constructionist theory as well as Williams’ (1992) glass escalator proposition The findings of this study confirm some of the factors related to career choice, experiences and barriers faced by men in nontraditional careers detailed in the literature. Three themes emerged for each research question: Experiences, advocacy, and benefits. Three themes emerged around the second research question exploring the experiences of men in a female-concentrated profession: The male body, communication, and perception. Three themes arose around the third research question: administration, My Masculinity, and pay. The findings run counter to Williams’ glass escalator proposition, which posits men working in female-concentrated professions are at an advantage. The findings advance support for Buschmeyer’s theory of (2013) alternative masculinity.

Olfactory dysfunction in young smokers J.

To establish the prevalence of olfactory dysfunction in smoking and non-smoking students of our Faculty who attend the Department of Otolaryngology (ENT) of our Hospital. Materials and method: Students (smokers and non-smokers) that do and do not suffer from olfactory dysfunction. We applied a questionnaire and a pocket smell test for screening all of the students. Results: We evaluated 207 students, between 18 and 30 years old; 50.7% (n=105) were women and 49.3% (n=102) were men. The smokers among them smoked up to 6 packs per year. One hundred twenty three students were non-smokers and 84 students were smokers. Of the 84 students who were smokers, 67 (79.7%) answered the Pocket Smell Test correctly (3/3) and 17 (20.2%) students had one or more errors. We had 123 non-smoker students and 103 (83.7%) students answered the Pocket Smell Test correctly and 20 (16.2%) answered with one or more errors. The prevalence of olfactory dysfunction in young smokers with a 95% conidence interval would be 32.8%. Conclusions: This study informed us about olfactory dysfunctions in our student population and their smoking habits. We corroborate that the Pocket Smell Test is reliable with the questionnaire; nevertheless it is a screening test. We have a population of young people who smoke one cigarette per day and who didn’t have a signiicant alteration in their ability of smell at the time of the study. This is consistent with medical literature. More studies should be conducted in order to expand this information.