Characterization of Polyetherimide Under Static, Dynamic, and Multiple Impact Conditions

The application of polymers in robust engineering designs is on the rise due to their excellent mechanical properties such as high fracture toughness, specific strength, durability, as well as, thermal and chemical resistances. Implementation of some advanced polymeric solids is limited due to the lack of available mechanical properties. In order for these materials to endure strenuous engineering designs it is vital to investigate their response in multiple loading rates and conditions. In this thesis, the mechanical response of polyethermide (PEI) is characterized under quasi-static, high strain rate, and multiple impact conditions. Standard tension, torsion, and compression experiments are performed in order to distinguish the multi-regime response of PEI. The effects of physical ageing and rejuvenation on the quasi-static mechanical response are investigated. The strain softening regime resulting from strain localization is eliminated by thermal and mechanical rejuvenation, and the advantages of these processes are discussed. The dynamic fracture toughness of the material in response to notched impact via Charpy impact test is evaluated. The high strain-rate response of PEI to uniaxial compression is evaluated at rates exceeding 104/s via miniaturized Split Hopkinson Pressure Bar (MSHPB), and compared to the quasi-static case to determine strain-rate sensitivity. The elastic response of the aged material to multiple loading conditions are correlated using the Ramberg-Osgood equation, while the elastoplastic response of rejuvenated PEI is correlated using a both the Ramberg-Osgood equation and a novel model. The strain-rate sensitivity of the strength is found to be nominally bilinear and transition strains are modeled using the Ree-Erying formulation. Finally, multiple impact experiments are performed on PEI using the MSHPB and a model is proposed to quantify damage as a result of collision

Use of municipal solid waste landfill as heat source of heat pump

The heat pump systems are considered today an environmentally friendly technology and, together with other energy production systems from renewable sources, are fundamental for reducing energy consumption and the resulting greenhouse gas emissions due to air conditioning of buildings. The ground source heat pumps use the ground as a heat source able to provide the better energy performance if compared with more common systems which using air as source. The increase of the temperatures inside the controlled landfills of municipal solid waste (MSW), due to the decomposition of waste materials can make the volume of waste a viable alternative in this context, to be used as a heat source for the production of heat. The present work has the objective of analyzing the potential of use of a MSW landfill for space heating through a heat pump. The first part of the work analyzes the main features of a landfill of municipal solid waste starting from system design through to biological degradation processes of organic matter. Subsequently the possible configurations of heat exchangers to be inserted within or covering the landfill is discussed. Based on the findings found in the literature, a dynamic model has been created for a real case study of a MSW landfill located in the north-east of Italy. Boundary conditions (i.e. annual temperature cycles for the soil, heat exchange by convection with the ambient air and radiation, a heat generation function distributed on the rejection of mass) have been imposed to the model in order to carry out annual simulations by means of finite element method, thanks to which the values of temperature reached by the mass of waste have been obtained. By means of the creation of a thermal load profile of a group of users it has been possible to determine the total energy extracted from the landfill and the electricity needed for the operation of the heat pump. The potential energy saving achievable with this type of plant was obtained by comparison with a ground source heat pump using horizontal pipes

Use of Municipal Solid Waste Landfill as Heat Source of Heat Pump

Abstract The heat pump systems are considered today an environmentally friendly technology and, together with other energy production systems from renewable sources, are fundamental for reducing energy consumption and the resulting greenhouse gas emissions due to air conditioning of buildings. The ground source heat pumps use the ground as a heat source able to provide the better energy performance if compared with more common systems which using air as source. The increase of the temperatures inside the controlled landfills of municipal solid waste (MSW), due to the decomposition of waste materials can make the volume of waste a viable alternative in this context, to be used as a heat source for the production of heat. The present work has the objective of analyzing the potential of use of a MSW landfill for space heating through a heat pump. The first part of the work analyzes the main features of a landfill of municipal solid waste starting from system design through to biological degradation processes of organic matter. Subsequently the possible configurations of heat exchangers to be inserted within or covering the landfill is discussed. Based on the findings found in the literature, a dynamic model has been created for a real case study of a MSW landfill located in the north-east of Italy. Boundary conditions (i.e. annual temperature cycles for the soil, heat exchange by convection with the ambient air and radiation, a heat generation function distributed on the rejection of mass) have been imposed to the model in order to carry out annual simulations by means of finite element method, thanks to which the values of temperature reached by the mass of waste have been obtained. By means of the creation of a thermal load profile of a group of users it has been possible to determine the total energy extracted from the landfill and the electricity needed for the operation of the heat pump. The potential energy saving achievable with this type of plant was obtained by comparison with a ground source heat pump using horizontal pipes

A comparison study of the orthographics mistakes of students with inferior and students with average writing performance

OBJETIVO: O objetivo deste estudo foi comparar se crianças com baixo desempenho em escrita cometem mais erros ortográficos que crianças da mesma série com desempenho satisfatório nesta tarefa, e quais os tipos de erros ortográficos mais freqüentes. MÉTODOS: Participaram deste estudo 24 crianças da 2ª série do ensino fundamental de uma escola pública, avaliadas individualmente. O teste aplicado foi o subteste de escrita do Teste de Desempenho Escolar, composto por 34 palavras que são ditadas aos alunos. RESULTADOS: Os alunos com desempenho inferior em escrita cometeram significativamente mais erros ortográficos que o grupo com desempenho satisfatório. Os erros que tiveram diferença estatisticamente significativa entre os dois grupos foram erros do tipo hipercorreção, dificuldade com marcadores de nasalização, relação fonografêmica irregular, omissões de sílabas e erros por troca de letras. Também houve correlação fortemente negativa entre erros ortográficos e desempenho em escrita. CONCLUSÕES: Quanto melhor o desempenho em escrita, menos erros ortográficos possui a elaboração gráfica do aluno. Os erros mais freqüentes no grupo com desempenho baixo, que os difere do outro grupo, dizem respeito aos erros de relação fonografêmica irregular, omissões de sílabas, dificuldade no uso de marcadores de nasalização, hipercorreção e erros por troca de letras. Com o avanço da capacidade de aprendizagem da criança, o desempenho ortográfico tende a melhorar.PURPOSE: The aim of this study was to verify whether children with poor writing performances make more orthographic mistakes than children of the same school grade with average performances, and what are the most frequent types of orthographic mistakes. METHODS: Twenty-four second grade children from a public school were individually analyzed in this study. The test used was the writing subtest of the School Performance Test, which is composed by 34 words that are dictated to the students. RESULTS: Students with lower performances had significantly more orthographic mistakes than the group of children with average writing performances. The mistakes that were statistically different between children of the two groups were: hypercorrection mistakes, difficulties with nasal markers, irregular phonographemic relation, syllable omission, and letter changes. There was also a strongly negative correlation between orthographic mistakes and writing performance. CONCLUSION: The results showed that the better the writing performance, the lesser the orthographic mistakes made by the subjects. The most frequent mistakes made by children with poor writing skills were: irregular phonographemic relation, syllable omission, difficulties with nasal markers, hypercorrection errors and letter changes. These types of mistakes were different from the average student; however, the orthographic performance tends to improve with the improvement of the children's learning capacity

variables affecting evaluation and publication of oncology case reports a systematic analysis

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Words for pharma: a quantitative and qualitative analysis on vision, mission and values of multinational pharma companies.

Introduction: Pharma companies deal with the same important challenges that humans face: to grow and stay healthy. The crucial role of pharma companies in preserving health would suggest that they might rank highly in the reputation indexes. However, this does not seem to be the case. Our aim was to collect, cluster and analyse the words used by pharma companies in their mission, vision and value statements as a base to identify areas of improvement in their corporate communication. Methods: A total of 97 multinational pharma companies were selected based on their size and presence within major markets. Mission, vision and company values were captured from company websites and analysed. Word clouds were built to analyse the frequency of words in the statement. The influence of company size and location was also analysed. Results: Most companies (90.7%) have a mission and 54.6% have a clearly stated vision statement, 71.4% mention values. "Life/lives" "patients", "innovative", "people/persons" are the most frequently used words. "Innovation" and "integrity" are by far the most common values, followed by "respect", "ethics", "responsibility" and "passion". References to healthcare professionals, access to treatment and sustainability, open science, transparency and care for the environment are more scanty. Conclusions: Most, but not all, pharma companies provide comprehensive statements focussing mostly on the innovation and its impact on patients. Topics such as role of health care professionals, economic sustainability and care for the environment are rarely listed. An in-depth analysis of their alignment with key needs and trending topics is warranted to further engage customers and build reputation and value. (Digital health

Preoperative SARS-CoV-2 infection screening before thoracic surgery during COVID-19 pandemic: a multicenter retrospective study

Objectives. During coronavirus disease (COVID-19) pandemic, preoperative screening before thoracic surgery is paramount in order to protect patients and staff from undetected infections. This study aimed to determine which preoperative COVID-19 screening tool was the most effective strategy before thoracic surgery. Methods. This retrospective cohort multicenter study was performed at 3 Italian thoracic surgery centers. All adult patients scheduled for thoracic surgery procedures from 4th March until 24th April, 2020, and submitted to COVID-19 preoperative screenings were included. The primary outcome was the yield of screening of the different strategies. Results. A total of 430 screenings were performed on 275 patients; 275 anamnestic questionnaires were administered. 77 patients were screened by an anamnestic questionnaire and reverse transcriptase polymerase chain reaction (RT-PCR). 78 patients were selected to combine screening with anamnestic questionnaire and chest computed tomography (CT). The positive yield of screening using a combination of anamnestic questionnaire and RT-PCR was 7.8% (95% CI: 2.6-14.3), while using a combination of anamnestic questionnaire and chest CT was 3.8% (95% CI: 0-9). Individual yields were 1.1% (95% CI: 0-2.5) for anamnestic questionnaire, 5.2% (95% CI: 1.3-11.7) for RT-PCR, and 3.8% (95% CI: 0-9). Conclusions. The association of anamnestic questionnaire and RT-PCR is able to detect around 8 positives in 100 asymptomatic patients. This combined strategy could be a valuable preoperative SARS-CoV-2 screening tool before thoracic surgery

Influence of diabetes on mortality in acute myocardial infarction: Data from the GISSI-2 study

AbstractObjectives. This study was conducted to determine the role of insulin-dependent and noninsulin-dependent diabetes in the prognosis of patients after myocardial infarction and treatment with fibrinolytic agents.Background. Several studies have shown that diabetic patients have a high mortality rate after acute myocardial infarction. However, the impact of diabetes on survival in patients treated with fibrinolytic agents is still undefined. It is also not known whether the type of diabetes or gender affects prognosis.Methods. We analyzed prevalence and prognostic significance of a history of diabetes in patients enrolled in the GISSI-2 study, all of whom received fibrinolytic agents. The incidence of deaths in the hospital and at 6 months after study entry was computed for patients without diabetes and for insulin-dependent and noninsulin-dependent diabetic patients; relative risks were evaluated by univariate and multivariate analysis.Results. Information on diabetic status was available for 11,667 patients, 94.2% of those randomized in the GISSI-2 study. The prevalence of diabetes was higher in women than in men (8.75% vs. 1.85%, p < 0.01 for insulin-dependent and 23.7% vs. 13.8%, p < 0.01 for noninsulin-dependent diabetic patients). The type of fibrinolytic agent did not affect mortality rates; the increase in in-hospital mortality of diabetic patients was moderate and similar for men with insulin- and noninsulin-dependent diabetes (8.7% and 10.1%, respectively, vs. 5.8% in nondiabetic patients); in women, mortality was markedly higher for insulin-dependent and only slightly higher for noninsulin-dependent diabetic patients (24.0% and 15.8%, respectively, vs. 13.9% for nondiabetic patients). The adjusted relative risks were 1.9 (95% confidence interval 1.2 to 2.9) for insulin-dependent diabetic women and 1.4 (95% confidence interval 1.1 to 1.8) for noninsulin-dependent diabetic men. The mortality rate after discharge showed a similar gender difference, and in insulin-dependent diabetic women, prognosis was ominous even in the absence of left ventricular damage before discharge.Conclusion. A history of diabetes is associated with a worse prognosis after myocardial infarction, even in patients treated with fibrinolytic agents. Gender and type of diabetes appear to be critical in affecting survival. In men, both insulin-dependent and noninsulin-dependent diabetes are associated with a moderately higher mortality rate; in women, insulin-dependent diabetes is, in itself, a strong risk factor for death after myocardial infarction

Aspectos éticos e econômicos da tributação sob uma perspectiva hoppeana

O presente trabalho tem como objetivo analisar a ética e a economia da tributação sob a luz dos ensinamentos desenvolvidos por Hans-Hermann Hoppe.  Com supedâneo na Ética Argumentativa Hoppeana, o artigo aborda as consequências econômicas da espoliação legal, valendo-se, para tanto, da metodologia desenvolvida pela Escola Austríaca de Economia, corrente de pensamento econômico da qual Hoppe faz parte. Ademais, Hans Hoppe deixa claro que a tributação deve ser vista – acima de tudo – como um meio de destruição da propriedade e formação de riqueza. Em suma, as obras de Hans-Hermann Hoppe caracterizam-se por uma intransigente defesa moral e intelectual do direito de propriedade privada, cujas lições pouco ortodoxas sintetizam, por um lado, uma profunda crítica ética ao ato de tributar e, por outro, a destruição de riqueza que esse instituto causa.   

Narrativa escrita de escolares com e sem dificuldade de consciência sintática

Introduction: Syntactic awareness is a metalinguistic ability defined as the child’s ability to reflect on formal processes relating to the organization of words in sentences and to manipulate them. This skill is still little explored in the context of school learning, and its importance in the school learning process of Portuguese-speaking children is poorly described. Objective: To compare written narrative between children with and without difficulty in syntactic awareness. Methods: The study was conducted on 60 children (mean age 9.4 years; SD: 0.9) enrolled in the 4th and 5th years of elementary school in a municipal school. The subjects were divided into two groups according to their performance in the task of syntactic awareness - G1 (children with medium/high performance in syntactic awareness) and G2 (lower performance). After the assessment of syntactic awareness each child elaborated a written narrative text based on a stimulus figure. This text was analyzed by judges in terms of spelling, grammatical errors, use of grammatical classes, and content. The Student t-test (α = 0.05) was used to compare the groups. Results: G2 children showed altered handwriting; greater occurrence of spelling mistakes, mainly of irregular phonographic relation type; oral support and difficulty with nasal markers; short texts with preference for the use of nouns and verbs, as well as difficulties with text structuring, use of punctuation and vocabulary, while G1 used more verbs and pronouns instead of nouns. Conclusions: Children with adequate syntactic awareness were able to elaborate written narratives with greater competence, demonstrating acquisition of orthographic aspects and development of textual coherence.Introdução: A consciência sintática é uma habilidade metalinguística e é definida como a capacidade da criança em refletir sobre os processos formais relativos à organizaçãodas palavras em frases e manipulá-los. Esta é uma habilidade ainda pouco explorada no contexto de aprendizagem escolar, sendo pouco descrito a sua importância no processo de aprendizagem escolar de crianças falantes do português. Objetivo: Comparar a narrativa escrita entre crianças com e sem dificuldade em consciência sintática. Método: Participaram 60 crianças (idade média 9,4 anos; DP: 0,9) matriculadas no 4º e 5º ano do ensino fundamental de uma escola municipal, divididas em dois grupos, de acordo com seu o desempenho na tarefa de consciência sintática – G1 (crianças com desempenho médio/elevado em consciênciasintática) e G2 (desempenho rebaixado). Após a avaliação da habilidade de consciência sintática, cada criança elaborou um texto narrativo escrito baseado em uma figura estímulo que foi analisado nos aspectos grafia, erros ortográficos, uso dasclasses gramaticais e o conteúdo. Para comparação entre os grupos usou-se o teste T – student (α = 0,05). Resultados: As crianças do G2 apresentaram grafiaalterada; maior ocorrência de erros ortográficos, sendo estes principalmente do tipo relação fonografêmica irregular; apoio na oralidade e dificuldade com marcadores de nasalização;textos curtos com preferência do uso de substantivos e verbos, além de dificuldades com a estruturação do texto, uso de pontuação e vocabulário, enquanto que o G1 utilizou maisverbos e pronomes no lugar dos substantivos. Conclusão: Crianças que apresentam adequada habilidade de consciência sintática conseguiram elaborar narrativas escritas com maior competência, demonstrando aquisição de aspectos ortográficos e desenvolvimento da coerência textual