A hybrid procedure to identify the optimal stiffness coefficients of elastically restrained beams

The formulation of a bending vibration problem of an elastically restrained Bernoulli-Euler beam carrying a finite number of concentrated elements along its length is presented. In this study, the authors exploit the application of the differential evolution optimization technique to identify the torsional stiffness properties of the elastic supports of a Bernoulli-Euler beam. This hybrid strategy allows the determination of the natural frequencies and mode shapes of continuous beams, taking into account the effect of attached concentrated masses and rotational inertias, followed by a reconciliation step between the theoretical model results and the experimental ones. The proposed optimal identification of the elastic support parameters is computationally demanding if the exact eigenproblem solving is considered. Hence, the use of a Gaussian process regression as a meta-model is addressed. An experimental application is used in order to assess the accuracy of the estimated parameters throughout the comparison of the experimentally obtained natural frequency, from impact tests, and the correspondent computed eigenfrequency.

Inspecção, diagnóstico e projecto no âmbito da reabilitação de edifícios antigos do Porto

Mestre em Engenharia Civil - Especialização em Estruturas

An evaluation of the direct agglutination test to diagnose "Mal de Caderas" disease

Se evaluó la utilidad de la prueba de aglutinación directa (AD) para diagnosticar el Mal de Caderas. Se emplearon cuarenta y cuatro sueros provenientes de dos lotes de equinos naturalmente infectados con el Trypanosoma evansi (Lote 1 y Lote 2). La AD fue positiva (Aglutinación > 1:512) en 13 de 16 equinos (81.2%), de los que se aislaron los parásitos. En doce de estos animales (92%) se detectaron IgM anti T. evansi mediante la AD realizada con 2-mercaptoetanol (AD + 2-ME). La AD fue positiva en 17 de los 28 equinos que resultaron negativos al diagnóstico parasitológico. Un tercer lote de cinco equinos infectados con T. evansi que presentaba elevados títulos de AD, fue tratado con Suramina Sódica (Nagano1-Bayer). La AD + 2-ME evidenció en cuatro animales que, gran parte de estos anticuerpos se ubicaban en la fracción IgM. Posterior al tratamiento farmacológico y, en concordancia de la negativización de la parasitemia, la detección de la IgM anti T. evansi no fue posible, mientras que los anticuerpos IgG continuaron detectándose a los doce meses post-tratamiento en valores de 1:512, en tres animales. Cincuenta sueros de equinos de una zona libre del parásito, que se emplearon como controles, fueron negativos a la AD. Se recomienda la utilización de la AD y AD + 2-ME para el uso de rutina en el diagnóstico del Mal de Caderas de los equinos, en combinación con otros métodos parasitológicos sensibles.

Gelatin particle indirect agglutination test for serodiagnosis of schistosomiasis: comparative study with enzyme-linked immunosorbent assay

A new serological test, the gelatin particle agglutination test (GPAT), was used for the serodiagnosis of schistosomiasis mansoni. This technique showed the sensitivity (90.6%) and specificity (97.8%) close to those of enzyme-linked immunosorbent assay. The GPAT can be easily and rapidly performed without specialized equipment, by using lyophilized antigen-coated gelatin particles. The test also seems to be useful for mass screening of Schistosoma infection in field conditions.

Utilização de métodos ópticos de correlação de imagem para a determinação da tenacidade à fractura de adesivos estruturais

Mestrado em Engenharia Mecânica

Bacterial antigen detection in cerebrospinal fluid by the latex agglutination test

Eighty purulent cerebrospinal fluid (CSF) samples from patients with clinical evidence of meningitis were studied using the Directigen latex agglutination (LA) kit to determine the presence of bacterial antigen in CSF. The results showed a better diagnostic performance of the LA test than bacterioscopy by Gram stain, culture and counterimmunoelectrophoresis (CIE), as far as Neisseria meningitidis groups B and C, and Haemophilus influenzae type b are concerned, and a better performance than bacterioscopy and culture considering Streptococcus pneumoniae. Comparison of the results with those of culture showed that the LA test had the highest sensitivity for the Neisseria meningitidis group C. Comparing the results with those of CIE, the highest levels of sensitivity were detected for N. meningitidis groups B and C. Regarding specificity, fair values were obtained for all organisms tested. The degree of K agreement when the LA test was compared with CIE exhibited better K indices of agreement for N. meningitidis groups B and C.

Resistência ao fogo de alvenarias sem função estrutural

Um incêndio é algo difícil de prever, assim como a sua consequência nos elementos de construção. Dessa forma, ao longo das últimas décadas, os elementos de construção têm sido alvo de diversos estudos a fim de avaliar os seus comportamentos quando solicitados em situação de incêndio. O International Building Code (IBC) descreve um método de cálculo analítico para a determinação da resistência ao fogo dos elementos da construção de acordo com os procedimentos de teste estabelecidos na ASTM E119 (Standard Test Methods for Fire Tests of Building Construction and Materials). Nesta dissertação foi feita uma análise desse método, que se mostrou inadequado para estimar a resistência ao fogo das alvenarias, sem função estrutural, de blocos cerâmicos e blocos de betão, uma vez que despreza qualquer efeito do ar no interior das mesmas. No seguimento desta análise, é apresentado um desenvolvimento do método descrito tendo em conta o efeito do ar. Depois de uma análise aos vários tipos de blocos cerâmicos e de betão com diferentes dimensões e geometrias foi possível obter uma relação entre a espessura equivalente de ar existente num bloco e a sua respectiva resistência ao fogo, de modo a serem obtidos os valores descritos na normalização existente. O efeito do ar mostrou ter uma maior influência na resistência ao fogo nas alvenarias constituídas por blocos cerâmicos de furação vertical, já que a sua geometria caracterizada por um elevado número de pequenos alvéolos contribui para o aumento do isolamento térmico, e consequentemente da sua resistência ao fogo. Nas alvenarias rebocadas os valores da resistência ao fogo aumentam cerca de 50%, quando revestidos com argamassa de cimento, e 70% quando revestidos com gesso, logo, o emprego de revestimentos representam uma boa alternativa para aumentar a resistência ao fogo.

Entamoeba histolytica: fecal antigen capture immunoassay for the diagnosis of enteric amebiasis by a monoclonal antibody

Amebiasis continues to be of epidemiological importance in underdeveloped countries. Clinical diagnosis and epidemiological setting in a region are based on the fecal microscopic identification of cysts or trophozoites. This procedure requires well trained personnel, is laborious, of low sensitivity and frequently yields false-positives results. The present study was designed to develop an immuno-enzymatic fecal 96 kDa antigen capture test (COPROELISA-Eh) more sensitive and specific than microscopic diagnosis of amebiasis. Triplicates of 177 stool samples processed by the formol-ether concentration method, were defined as positive or negative by three experienced microscopic observers. Another aliquot was submitted to the antigen capture test by a monoclonal antibody against a specific membrane antigen of pathogenic strains of Entamoeba histolytica. Optical densities were interpreted as positive when they exceeded the mean value of negative samples plus two standard deviations. COPROELISA-Eh showed a 94.4% sensitivity, 98.3% specificity, 96.2% positive predictive value and 97.6% negative predictive value for the detection of E. histolytica in feces. COPROELISA-Eh is more sensitive and specific than microscopic examination, does not require specially trained personnel and allows the simultaneous processing of a large number of samples.

TRH-TSH test in patients with schistosomiasis chronic forms

Diversas alterações na concentração sérica dos hormônios tiroidianos têm sido descritas em associação a doenças crônicas não-tiroidianas. Com relação às doenças hepáticas crônicas, a síndrome do T3 baixo foi descrita em pacientes cirróticos, enquanto a síndrome do T4 elevado foi encontrada em esquistossomóticos com a forma hepatoesplênica compensada. Com o intuito de verificar se as alterações relatadas na esquistossomose mansônica eram de origem "periférica" ou "central", realizamos a prova do TRH-TSH em 12 pacientes esquistossomóticos "puros" (6 hepatointestinais e 6 hepatoesplênicos compensados) e em 5 indivíduos controle. Os resultados obtidos demonstram que o eixo hipotálamo-hipofisário é normal nas formas crônicas da esquistossomose e que provavelmente as alterações previamente relatadas devem ser '"periféricas" e não " centrais".

Multi-Agent Based Smart Grid Management and Simulation: Situation Awareness and Learning in a Test Bed with Simulated and Real Installations and Players

The rising usage of distributed energy resources has been creating several problems in power systems operation. Virtual Power Players arise as a solution for the management of such resources. Additionally, approaching the main network as a series of subsystems gives birth to the concepts of smart grid and micro grid. Simulation, particularly based on multi-agent technology is suitable to model all these new and evolving concepts. MASGriP (Multi-Agent Smart Grid simulation Platform) is a system that was developed to allow deep studies of the mentioned concepts. This paper focuses on a laboratorial test bed which represents a house managed by a MASGriP player. This player is able to control a real installation, responding to requests sent by the system operators and reacting to observed events depending on the context.

A simple PCR-based procedure for plaque diagnosis

Supernatant of boiled spleen saline-suspensions of Yersinia pestis experimentally infected animals were used as template for PCR amplification without DNA extraction. PCR sensitivity was enhanced by a second round of amplification (Nested). No amplification was observed from non-infected animals.

HEMAGGLUTINATION TEST FOR THE DIAGNOSIS OF HUMAN NEUROCYSTICERCOSIS: DEVELOPMENT OF A STABLE REAGENT USING HOMOLOGOUS AND HETEROLOGOUS ANTIGENS

A hemagglutination (HA) test was standardized using formalin- and tannin-treated gander red blood cells sensitized with a total salt extract of C. cellulosae (HA-Cc) and an antigenic extract of Cysticercus longicollis (HA-Cl) vesicular fluid. A total of 61 cerebrospinal fluid (CSF) samples were assayed, 41 from patients with neurocysticercosis and 20 from a control group, which were, respectively, reactive and non-reactive to ELISA using C. cellulosae. The CSF samples from the control group did not react and 35 (85.4%) and 34 (82.9%) CSF samples from patients were reactive to the HA-Cc and HA-Cl tests, respectively. The reagents ready for use were stable up to 6 months when stored at 4°C in 50% glycerol. The present results confirm that the reagent using Cysticercus longicollis stabilized with glycerol can be used as an alternative in the immunological diagnosis of neurocysticercosis

EPIDEMIOLOGICAL SURVEY ON CANINE POPULATION WITH THE USE OF IMMUNOLEISH SKIN TEST IN ENDEMIC AREAS OF HUMAN AMERICAN CUTANEOUS LEISHMANIASIS IN THE STATE OF RIO DE JANEIRO, BRAZIL

A survey for canine tegumentary leishmaniasis (CTL) has been carried out between 1986 and 1993 in seven endemic localities for American cutaneous leishmaniasis in the State of Rio de Janeiro. 270 dogs have been examined for their clinical aspects, the development of delayed hypersensitivity (DHS) with Immunoleish antigen and with immunofluorescent antibody research of IgG (IF). 28.2% of them had ulcer lesions and 3.3% had scars. The lesions consisted of single (39.5%) and mucocutaneous lesions (31.6%), multiple cutaneous (25.0%) and mucocutaneous lesions associated with cutaneous ulcers (4.0%). Twelve (15.8%) isolates from biopsies were analyzed by zimodeme and schizodeme and identified as L. (V.) braziliensis. The overall prevalence of canine infection that was evaluated with the skin test was of 40.5% and with IF it was of 25.5%. Both tests showed a high positive rate with relation to the animals with mucosal lesions, as in the case of human mucocutaneous leishmaniasis. The comparison of the two tests showed the skin test to have a better performance although there was no statistical difference (p>0.05) between them. The proportional sensitivity and specificity was of 84.0% and 74.0%, respectively. The Immunoleish skin test and IF are useful tools to be employed in CTL field epidemiological surveys.

THE PERSISTENCE OF LEPTOSPIRAL AGGLUTININS TITERS IN HUMAN SERA DIAGNOSED BY THE MICROSCOPIC AGGLUTINATION TEST

The persistence of agglutinins detected by MAT has created some problems to the interpretation of the results. The aim of this study was to examine the data of serology from 70 patients with serologically confirmed diagnosis of leptospirosis by during 3-13 months after being affected with leptospires in order to elucidate the interpretation of the persistence of agglutinins detected by MAT. Sixty-one patients sera (87.14%) had titers equal or greater than 800. Of these, two individuals maintained titers of 800 thirteen months after the onset. This study showed that only one sample of sera with high titers is not reliable to determine the time at which infection occurred.