Numerical analysis of cellular steel beams failure modes in fire conditions

Cellular beam generally originates from steel hot-rolled I-section member, which the web is cut, displaced and subsequently welded (Westok method) to obtain openings in the web spaced regularly, with different forms like circular, sinusoidal or hexagonal, see Figure 1. The procedure results in a deeper beam, approximately 40-60% deeper than its parent solid section, [1]. This type of beam is increasingly used because it is capable to support long spans, it can have a bending resistance up to 2.5 times higher than its parent section and its openings allow the passage of technical equipment and ventilation systems through their web, which reduces the floor height and therefore the overall height of building. The presence of the opening influences in the failure modes of the beam. Vierendeel mechanism and web post buckling (WPB) are examples of failure modes originate due the openings, while already existing failure modes on solid beams are modified in cellular beams, such as lateral-torsional buckling (LTB), [2]. Besides that, exposure to high temperatures has a detrimental effect on the steel resistance, which added to the initial imperfections of the beam results in the combination of failure modes previously mentioned. For that reason, the main purpose of the study will be to define the failure modes, in particular WPB and LTB, and the beam resistance, relating the temperature with variant geometric parameters, comparing the results obtained by simple calculation methods proposed by Eurocode 3 and Steel Construction Institute (SCI) with numerical results. For this purpose, a finite element model is developed in the software Ansys to study the influence of different geometric parameters, considering geometric imperfections and residual stresses in the beams. Results are compared considering different geometric characteristics and temperatures with design values obtained from the Eurocode EC3-1-2 and the Eurocode new draft EC3-1-13, [3].info:eu-repo/semantics/publishedVersio

Numerical analysis of cellular steel beams failure modes in fire conditions

Beams with long spans are increasingly used in the steel building constructions and usually are used with openings for technical equipment and ventilations systems cut in their web. These elements are structural steel beams that are deeper than normal rolled sections, with distributed circular openings, or other like squared or hexagonal, that are produced by cutting and welding hot rolled steel sections (Westok method). The split halves are then offset and welded together to form a deeper beam with full circular or hexagonal shaped web openings, which results in a beam approximately 40-60% deeper than its solid parent section, [1], see Figure 1. This method reduces the floor height and therefore the overall height of building.info:eu-repo/semantics/publishedVersio

Haplotype of prostaglandin synthase 2/cyclooxygenase 2 is involved in the susceptibility to inflammatory bowel disease

AIM: Prostaglandin G/H synthase 2 (PTGS2 or COX2) is one of the key factors in the cellular response to inflammation. PTGS2 is expressed in the affected intestinal segments of patients with inflammatory bowel diseases (IBD). In IBD patients, non-steroidal anti-inflammatory drugs, which have been shown to reduce both the production and activity of PTGS2, may activate IBD and aggravate the symptoms. We aimed at examining genetic variants of PTGS2 that may be risk factors for IBD. METHODS: We genotyped 291 individuals diagnosed with IBD and 367 controls from the Dutch population for the five most frequent polymorphisms of the PTGS2 gene. Clinical data were collected on all patients. DNA was extracted via normal laboratory methods. Genotyping was carried out using multiplex PCR followed by the Invader Assay and the 5 exonuclease assay (TaqMan). New polymorphism screening was performed by pre-screening with denaturing high-performance liquid chromatography, followed by fluorescent sequencing. RESULTS: Allele 5209G was weakly associated with Crohn's disease (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.03-2.57), and allele 8473T with ulcerative colitis (OR 1.50, 95%CI 1.00-2.27). The haplotype including both alleles showed a strong association with IBD (OR 13.15, 95%CI 3.17-116.15). This haplotype, while rare (-0.3%) in the general population, is found more frequently in patients (3.5%). CONCLUSION: Our data suggest that this haplotype of PTGS2 contributes to the susceptibility of IBD

A comparison of baleen whale density estimates derived from overlapping satellite imagery and a shipborne survey

As whales recover from commercial exploitation, they are increasing in abundance in habitats that they have been absent from for decades. However, studying the recovery and habitat use patterns of whales, particularly in remote and inaccessible regions, frequently poses logistical and economic challenges. Here we trial a new approach for measuring whale density in a remote area, using Very-High-Resolution WorldView-3 satellite imagery. This approach has capacity to provide sightings data to complement and assist traditional sightings surveys. We compare at-sea whale density estimates to estimates derived from satellite imagery collected at a similar time, and use suction-cup archival logger data to make an adjustment for surface availability. We demonstrate that satellite imagery can provide useful data on whale occurrence and density. Densities, when unadjusted for surface availability are shown to be considerably lower than those estimated by the ship survey. However, adjusted for surface availability and weather conditions (0.13 whales per km2, CV = 0.38), they fall within an order of magnitude of those derived by traditional line-transect estimates (0.33 whales per km2, CV = 0.09). Satellite surveys represent an exciting development for high-resolution image-based cetacean observation at sea, particularly in inaccessible regions, presenting opportunities for ongoing and future research

INFUSÃO UTERINA COM BIGUANIDA POLIMÉRICA SOBRE A COLONIZAÇÃO BACTERIANA DO ÚTERO DE VACAS COM INFECÇÃO PUERPERAL APÓS RETENÇÃO DE ENVOLTÓRIOS FETAIS

This study was carried out with the aim to verify the utilization viability of polymeric biguanide solutions for the topic treatment of puerperal uterine infections in bovine females after premature parturition. Twenty Girolando cows of a dairy farm, with placenta retention and metritis were randomly distributed in two groups. Group 1, constituted of cows that received three uterine infusions of a polymeric biguanide solution, and Group 2, with animals that were not submitted to any treatment. There were taken uterine content samples at the first, third and fifth post partum weeks for bacteriological cultures, that means, before the first infusion, 14 and 28 days after treatment. The founds of bacteriological cultures in the two groups demonstrated that the solution of polymeric biguanide was not effective to reduce uterine bacteriological colonization in cows with post partum infections.Com o objetivo de estudar a viabilidade da utilização de biguanida polimérica, no tratamento tópico de infecções puerperais em fêmeas bovinas após o parto prematuro, 20 fêmeas Girolando pertencentes a um sistema de produção leiteira, que apresentaram retenção de envoltórios fetais e conseqüentemente endometrite puerperal, foram distribuídas aleatoriamente em dois grupos. O Grupo I, foi constituído de animais que receberam três infusões uterinas de biguanida polimérica; e o Grupo 2, animais não tratados. Foram realizadas colheitas de conteúdo uterino na primeira, terceira e quinta semanas pós-parto para realização de cultivos bacteriológicos, ou seja, antes da infusão, aos 14 e 28 dias após tratamento medicamentoso. O resultado dos cultivos bacteriológicos nos dois grupos demonstrou que a utilização da biguanida polimérica não reduziu a colonização bacteriana no útero dos animais tratados, em comparação àqueles não tratados