Abstract Deep beams do not behave according to classical beam theory. The nonlinearity of strain distribution within these elements requires application of strut and tie models (STM) or other alternatives to evaluate the complex stress field. Although the design of these elements is a common task for structural engineers, limited research is found on assessing effectiveness of the results. The purpose of this work is to compare, in a systematic approach, different design solutions for a deep beam using selected performance metrics which are strain energy, reinforcement ratio, maximum load, structural efficiency, safety factor and cracking behavior. A deep beam (2.85 m of height, 4.20 m of length and 0.2 m of thickness) with a square opening (0.7 m x 0.7 m) close to one of the supports was subjected to a uniform loading at the top surface while resting on supports at both ends. A simplified finite element model (FEM) of this beam was developed simulating concrete with elastic linear stress-strain behavior and disregarding steel reinforcements. This model allowed determination of elastic stress fields necessary to subsequent analyses. Four STM were then developed, supposing the total load respectively represented by one (STM-1), two (STM-2), four (STM-4) or eight (STM-8) concentrated loads equally spaced along the top of the beam. Additionally, an in-plane stress field method (SFM) was applied to the design of the same beam subjected to uniform loading on the top surface. After design and detailing of the reinforcement for each situation, nonlinear FEMs were used to predict the ultimate conditions. The strain energy reduced significantly comparing results from STM-1 to STM-2 and subsequently to STM-4 and remained at a low level in STM-8 and SFM. The reinforcement ratio reduced systematically from STM-1 to STM-8, was minimum with the SFM and the same behavior was followed by maximum load. The structural efficiency (maximum load/reinforcement ratio) increased from STM-1 to STM-8, with maximum efficiency at STM-8 and was slightly below with SFM. The safety factor reduced systematically from STM-1 to STM-8 and was slightly lower with SFM, but in all cases was above acceptable limits found in design codes.

Esse trabalho descreve um experimento simples e de fácil execução, destinado ao estudo da transferência de calor e massa por meio de uma aula prática. Tal estudo é realizado a partir da fusão de uma placa de gelo, ao ar ambiente, e com base na avaliação quantitativa do calor transferido por radiação, convecção e condensação de vapor d'água sobre a superfície dessa placa. Os valores teóricos, previstos a partir de equações relativas a esses processos de transferência de calor e massa, são comparados com dados experimentais relativos à taxa mássica de fusão dessa placa. A facilidade na execução dos ensaios e a simplicidade do equipamento empregado torna esse experimento uma atividade prática de fácil implementação em disciplinas que tratam da transferência de calor e massa. Além disso, a concordância entre valores teórico e experimental da taxa de transferência de calor e massa, e a metodologia empregada na análise e quantificação dessa taxa, viabilizam o experimento proposto como uma ferramenta pedagógica eficiente para o estudo desse tema.

This work describes a simple and easy-to-perform experiment, destined to the study of the heat and mass transfer by means of a practical class. This study is carried out from the melting of an ice sheet into ambient air and based on the quantitative evaluation of the heat transferred by radiation, convection and condensation of water vapor on the surface of that plate. The theoretical values, predicted from equations related to these processes of heat and mass transfers, are compared with experimental data concerning the melting mass rate of this plate. The ease of running the tests and the simplicity of the equipment employed makes this experiment a practical activity that is easy to implement in disciplines dealing with heat and mass transfer. In addition, the agreement between theoretical and experimental values of the heat and mass transfer rate, and the methodology used in the analysis and quantification of this rate, make feasible the proposed experiment as an efficient pedagogical tool to study this subject.

O antígeno nuclear de proliferação celular (PCNA) foi descrito como marcador da atividade proliferativa. Correlacionamos a marcação do PCNA com a evolução dos pacientes com carcinoma de células transicionais de bexiga. Revisamos 90 pacientes do HC-FMRP-USP de 1980-2000; com idade variando de 29 a 93 anos e média de 71 anos; sendo 77,8% homens e 22,2% mulheres; seguimento médio de 55 meses (2-231 meses). Constatamos 50% de tumores grau I, (32,2%) grau II e 17,8% grau III; estadiados em pTA-60%, pT1-8,9% e >pT1 31,1%. Utilizamos o anticorpo primário Monoclonal Mouse Anti-Proliferating Cell Nuclear Antigen (PCNA) Clone PC10 (DAKO). Foram contadas 500 células (X400), e utilizado ponto de corte de 50%. A análise estatística foi realizada com o teste de Mann-Whitney. Kaplan-Meier e Logrank Oitenta e sete tumores (96,66%) expressaram PCNA (mediana 72.5%, média 60,16%). Observamos diferença não significativa (P=0,39) na imunomarcação do PCNA entre tumores pT2-4 e pTA-1. A comparação de medias entre G1 e G2 (P=0,087), G1 e G3 (P=0,11) e entre G2 e G3 (P=0,66) não mostraram significado estatístico,assim como entre tumores com recidiva e sem recidiva (P=0,84). Os indivíduos PCNA positivos não tiveram intervalo livre de doença significativamente diferente (P=0,86); entretanto foi significativa a diferença nas curvas de sobrevida (P=0,003) e nas curvas de intervalos livres de metástase (P=0,01). A expressão imunohistoquímica do PCNA não foi efetiva para diferenciar os tumores mais avançados e agressivos, assim como para predizer recidivas. Desta forma, apesar da correlação com o tempo livre de metástase e a sobrevida, não mostrou utilidade prática.

Proliferating cell nuclear antigen (PCNA) expression was described as marker of the proliferative activity in urothelial tumors. We compared the PCNA immunostaining index with the outcome of patients with bladder cancer. We revised 90 patients, with age varying from 29 to 93 years (mean 71 yrs), being 77.8% men and 22.2% women; mean follow-up of 55 months (2-231 months). Fifty per cent of tumors were grade I; 32.2% grade II and 17.8% grade III. Primary tumor stage was: invasive (> >pT1=31.1% and superficial (pTA-1=68.9%). Eighty-seven tumors (96.6%) expressed PCNA (median 72.5%, mean 60.1%). The mean PCNA index was not different (p = 0.39) in superficial or invasive tumors. The comparison of immunostaining mean values between G1/G2 (p = 0.087), /G1/G3 (p = 0.11) and G2//g3 (p = 0.66) was not statistically significant, as well among recurring and non-recurring tumors (p = 0.84) but PCNA expression correlated with survival rate (p = 0.003) and metastases free intervals (p = 0.01) but not with recurrent free intervals (p = 0.86). In conclusion, PCNA over expression correlated with survival and metastasis free intervals, but was not significant to differentiate invasive stages, agressive grades and recurring tumors.

A expressão do MIB-1 é um excelente marcador da atividade proliferativa e correlaciona-se com a agressividade biológica do carcinoma de células transicionais da bexiga.Correlacionamos a expressão do MIB-1 com a evolução dos pacientes. Revisamos 90 pacientes do HC-FMRP-USP entre 1980-2000, com idade entre 29 a 93 anos (média 71 anos);sendo 70 (77,8%) homens e 20 (22,2%) mulheres; e seguidos em média por 55 (2-231) meses. 45 (50%) tumores tinham grau I, 29 (32,2%) grau II e 16 (17,8%) grau III. Os tumores foram estadiados em pTA: 54 (60%), pT1: 8 (8,9%) e pT2-4: 28 (31,1%). Foi utilizado o anticorpo monoclonal anti-MIB-1 (Immunotech). Emprega-se o limite de 10% de núcleos corados como nível de corte para o MIB-1. Utilizamos para análise estatística os testes Mann-Whitney, Kaplan-Meier, e log rank, e nível de significância 5%. Expressaram MIB-1, 63 pacientes (70%) variando de 0 a 80%(mediana 5%, média 22,8%), com diferença significativa (P<0,05) entre tumores invasivos (pT2-4) e não invasivos (pT A-1) e entre os estádios pT A e pT1 (P=0,01). Houve associação com o grau dos tumores: significativa entre G1 e G2 (P<0,001) e G1 e G3 (P<0,001), e sem significância entre G2 e G3 (P=0,2). A relação do MIB-1 com o tamanho da lesão foi significante (P<0,02). As recidivas não foram preditas pelo índice MIB-1 (P=0,86), entretanto em pacientes MIB-1 positivos foi significantemente menor o intervalo livre de metástase (P=0.04), e a sobrevida entre tumores não invasivos (P=0.009) e na população total (P=0.0002), Há correlação entre a alta expressão do MIB-1 e os estádios invasivos, os graus avançados e os tumores maiores, contudo, não há diferença em tumores recidivados. O índice de positividade do MIB-1 não distinguiu os pacientes com menor tempo livre da doença, foi, contudo, significante para apontar aqueles com menor sobrevida e tempo livre de metástase.

We investigate the immunoexpression of MIB-1 antigen on the outcome of the transitional carcinoma of the bladder. We revised 90 patients with a mean follow-up of 55 (2-231) months. Forty five (50%) tumors were grade I, 29 (32.2%), grade II and 16 (17.8%) grade III. The tumors were staged in pTa-1: 62 (68.9%) and pT2-4: 28 (31.1%). We considered positive the tumors with more than 10% imunostained cells. Sixty three patients (70%) expressed MIB-1, with significant difference (P <0,05) between invasive tumors (pT2-4) and non-invasive (pTA-1) and between pTA and pT1 tumors (P=0,01). There was also a significant association of MIB-1 immunostaining with tumor grade: G1 versus G2 (p < 0,001) and G1 versus G3 (p < 0,001). But such difference did not occur with G2 and G3 tumors ( p = 0,2). The relationship of MIB-1 expression with the size of the lesion was significant (p <0,02). The recurrence was not predicted by the MIB-1 labeling pattern (p=0,86), though, the MIB-1-positive patients had significant smaller metastasis free intervals (p = 0.04), and lower survival rates, both among superficial tumors (p=0.009) and in total sample (p = 0.0002).