Academia.edu no longer supports Internet Explorer.
To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser.
Dimensionamento de Vigas e Eixos 28 9.0-Dimensionamento de eixos e vigas. 9.1-Critérios de Resistência. No dimensionamento dos elementos de máquinas e estruturas, como os eixos e as vigas, vários são os critérios que podem ser utilizados para o estabelecimento de suas dimensões mínimas, compatíveis com as propriedades mecânicas dos materiais utiliza-dos, obtidas nos ensaios em laboratório. Tais critérios surgem quando se busca a resposta à seguinte questão básica:-quando ocorrerá a ruína* do material da peça carregada? *(entendemos como "ruína" a deterioração do material, por ruptura, por plastificação, por ser ultrapassado o limite de proporcionalidade, ou de escoamento etc, dependendo de seu uso). Várias poderiam ser as hipóteses (teorias) para sustentar uma resposta a tal ques-tão:-a ruína ocorre quando a maior tensão normal presente ultrapassar o valor da tensão normal ocor-rente quando da ruína do corpo de prova no ensaio de tração (ou compressão) do material;-a ruína ocorre quando a maior tensão tangencial presente ultrapassar o valor da tensão tangencial ocorrente quando da ruína do corpo de prova no ensaio do material correspondente;-a ruína ocorre quando a maior deformação longitudinal presente ultrapassar o valor da deforma-ção longitudinal ocorrente quando da ruína do corpo de prova no ensaio do material;-a ruína ocorre quando a maior energia específica de distorção presente ultrapassar o valor da ener-gia de distorção por unidade de volume ocorrente quando da ruptura do corpo de prova no ensaio do material.-outras... Como se verá, não há resposta única, válida para qualquer situação: o critério que mais se coaduna com os resultados obtidos em laboratório dependerá do tipo do material e do tipo do carregamento. 9.2-Teorias das Máximas Tensões. Válido para materiais frágeis (duros, quebradiços, que se rompem nos planos on-de a tensão normal é extrema) é o critério da máxima tensão normal, segundo o qual haverá ruína quando, em certo ponto do corpo, a tensão principal ultrapassar o valor da tensão de ruína no ensaio uniaxial do material. Portanto, o dimensionamento, para um dado CS, deve ser feito atendendo ao requisito (Critério de Coulomb): ½ (σ x + σ y) + √ [½ (σ x-σ y)] 2 + (τ xy) 2 < σ lim /CS...(9.2.1) √ [½ (σ x-σ y)] 2 + (τ xy) 2 < ½ σ lim /CS .....(9.2.2) Para materiais dúteis (macios, flexíveis, que se rompem nos planos onde a tensão tangencial é extrema), é o critério da máxima tensão tangen-cial o que melhor se coaduna, considerando que haverá ruína quando, em certo ponto, a tensão má-xima de cisalhamento ultrapassar o valor da tensão tangencial ocorrente (a 45º) no ensaio de tração do material (τ máx = ½ σ limite). O dimensionamento (para um dado CS) deve atender a que (Critério de Tresca): Fig.9.1-Tipos de fratura no ensaio de tração (a) material frágil; b) material dútil (inicialmente, a fratura se dá por cisalhamento até que a redução da área provoca a ruptura por tração). Planos de Clivagem 45º (a) (b)
Data mining techniques play very important role in health care industry. Liver disease is one of the growing diseases these days due to the changed life style of people. Various authors have worked in the field of classification of data and they have used various classification techniques like Decision Tree, Support Vector Machine, Naïve Bayes, Artificial Neural Network (ANN) etc. These techniques can be very useful in timely and accurate classification and prediction of diseases and better care of patients. The main focus of this work is to analyze the use of data mining techniques by different authors for the prediction and classification of liver patient.
2012 •
The well-grounded knowledge of the available numerical methods is of fundamental importance to get advantage of computational aided design. Concerning compressor development, the employment of Computational Fluid Dynamics is nowadays a must, however, very little attention has been given to the importance of the turbulence modeling in the prediction of flow behavior and, moreover, the heat transfer. The present paper reports an investigation of the turbulence models influence in the heat transfer prediction of the compressor suction system, specifically the suction muffler. The importance of the correct heat transfer modeling in the suction muffler represents great importance for the computation of the volumetric efficiency, additionally, influences significantly the thermal profile and suction valve behavior. In order to present such influence, the turbulent flow and heat transfer is modeled in the suction muffler of a hermetic refrigeration compressor. Several turbulence models are...
2016 •
Recent advances in the field of geometric morphometrics allow for powerful statistical hypothesis testing for effects of biological and environmental variables on anatomical shape. This study used partial least-squares regression (PLSR) and the recently developed bootstrapped response-based imputation modelling (BRIM) algorithm to test for sexual dimorphism in the craniofacial shape of 1-year-old humans. We observed a recession of the forehead in boys relative to girls, and differences in the nose, consistent with adult dimorphism. Results also suggest that the degree to which individuals express dimorphic traits is continuous throughout the population. This is also seen in adult dimorphism but in 1-year-olds the amount of overlap between groups is much higher, indicating the strength of dimorphism between sexes is lower. Our results demonstrate early sexual dimorphism that is not attributable to the influx of sex hormones at puberty. This highlights the need to look at very early o...
Nursing Current Jurnal Keperawatan
A Descriptive Study on Determinants of Preoperative Patient’s Compliance Using Chlorhexidine 2% [Studi Deskriptif Tentang Faktor-Faktor Yang Memengaruhi Kepatuhan Pasien Pre-Operasi Menggunakan Chlorhexidine 2%]2020 •
Chlorhexidine 2% used as an antiseptic soap in preparation before surgery at a central Indonesian hospital. But there were preoperative patients who are not compliant using Chlorhexidine 2%. The purpose of this study was to identify the determinants of patient compliance in using Chlorhexidine 2% before undergoing surgery. This research used descriptive quantitative design with cross sectional approach. The population was all preoperative patients who used Chlorhexidine 2% with a sample of 53 patients who were determined using purposive sampling technique. This instrument was a questionnaire that was adapted from previous studies and had tested the reliability validity of 30 respondents with r tables between 0.363 - 0.880 and Cronbach's alpha value 0.695. The results showed that more than half (62.3%) of respondents were not eligible to used Chlorhexidine 2%. Respondents with secondary education are 54.7% and more than half (51%) have low knowledge, more than half (67.9%) patien...
Journal of leukocyte biology
Deletion of BCG Hip1 protease enhances dendritic cell and CD4 T cell responses2018 •
Dendritic cells (DCs) play a key role in the generation of CD4 T cell responses to pathogens. Mycobacterium tuberculosis (Mtb) harbors immune evasion mechanisms that impair DC responses and prevent optimal CD4 T cell immunity. The vaccine strain Mycobacterium bovis Bacille Calmette-Guérin (BCG) shares many of the immune evasion proteins utilized by Mtb, but the role of these proteins in DC and T cell responses elicited by BCG is poorly understood. We previously reported that the Mtb serine protease, Hip1, promotes sub-optimal DC responses during infection. Here, we tested the hypothesis that BCG Hip1 modulates DC functions and prevents optimal antigen-specific CD4 T cell responses that limit the immunogenicity of BCG. We generated a strain of BCG lacking hip1 (BCGΔhip1) and show that it has superior capacity to induce DC maturation and cytokine production compared with the parental BCG. Furthermore, BCGΔhip1-infected DCs were more effective at driving the production of IFN-γ and IL-...
2012 •
Tujuan dari penelitian ini adalah mengetahui hubungan antara persepsi siswa terhadap gaya kepemimpinan guru dan motivasi belajar siswa kelas X SMK PGRI 2 Salatiga. Metode penelitian yang digunakan adalah metode korelasi. Subyek penelitian ini seluruh siswa kelas X SMK PGRI 2 Salatiga yang berjumlah 213 orang siswa. Data diperoleh melalui skala sikap yaitu skala sikap tentang Persepsi Siswa terhadap Gaya Kepemimpinan Guru dan Motivasi Belajar. Skala sikap tentang Persepsi Siswa terhadap Gaya Kepemimpinan Guru berisi tiga gaya kepemimpinan yaitu otoriter, laissez faire, dan demokratis. Teknik analisa yang digunakan adalah uji korelasi Spearman Brown. Berdasarkan hasil perhitungan diperoleh koefisien korelasi (rxy) sebesar 0,732 dan nilai signifikansi 0,000. Hal ini berarti bahwa ada hubungan yang positif dan signifikan antara Persepsi Siswa terhadap Gaya Kepemimpinan Guru dan Motivasi Belajar. Dari pengolahan data terhadap variabel persepsi siswa terhadap gaya kepemimpinan guru otorit...
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.
Frontiers in Immunology
To Be or Not to Be a Pathogen: Candida albicans and Celiac Disease2019 •
2016 •
Gestão & produção
Estruturação do problema de gerenciamento de desastres do estado de São Paulo por intermédio do método Strategic Options Development and Analysis2015 •
1982 •
International Journal of Medical Science and Public Health
Study on the factors associated with low birth weight among newborns delivered in a tertiary-care hospital, Shimoga, Karnataka2015 •
2017 •
1990 •
2020 •