52 research outputs found
Validation of a New Analytical Formula to Predict the Steel Temperature of Heavily Insulated Cross-Sections
Fire protection is a popular solution to slow down the temperature increase in steel elements subjected to fire, and simple equations, such as the mass lumped formula proposed in EN1993-1-2, may be employed to estimate the steel temperature in the cross-section. The EN1993-1-2 formula assumes that the temperature of the exposed insulation surface and the surrounding gas are equal. This simplification may provide inaccurate results for heavily insulated steel sections. Therefore, a new mass lumped formula was derived, accounting for more accurate boundary conditions considering the heat flux impinging the insulation. On these premises, this work evaluates how the new simple formula fares with respect to the EN1993-1-2 formula. In this respect, a comprehensive comparison with the results of 1-D and 2-D analyses considering several insulation materials and thicknesses of insulation and steel is thoroughly presented. The proposal results in being always safe and better estimates steel temperatures relevant in the structural fire engineering context. Its use is particularly recommended for heavily insulated sections, where the ratio between the insulation and the steel heat capacities is higher than 14, and the EN1993-1-2 formula gives unsafe predictions
A case of acute promyelocytic leukemia variant with derivative chromosome 3 der(3)t(3;8) associated with 8q partial gain
Background: Acute promyelocytic leukemia (APL) is characterized by fusion of PML/RARα genes as a result of t(15; 17)(q24;q21). APL is now one of the curable hematological malignancies thanks to molecularly targeted therapies based on all-trans retinoic acid (ATRA) and arsenic trioxide (ATX). Extramedullary (EM) relapse is a rare event in APL, ear involvement being even more infrequent, with only six cases so far described. About 30–35% of patients with newly diagnosed APL have additional cytogenetics abnormalities, whose prognostic significance is still controversial. The most common additional aberration is trisomy 8 or partial gain 8q. Case presentation: We describe here a novel unbalanced translocation der(3)t(3;8)(q29;q23.3-q24.3) associated with 8q partial gain in a 41 year-old man affected by APL in molecular remission after first line treatment, who had a responsive EM relapse in the auditory canal. Conclusions: EM relapse is a rare event in APL and ear involvement is even more infrequent. To our knowledge, this is the first reported case of APL with a new der(3)t(3;8)(q29;q23.3-q24.3) and 8q partial gain associated with t(15;17)(q24; q21). Despite the recurrence of the disease at EM level, the clinical outcome of this patients was favorable
Atypical mature T-cell neoplasms: The relevance of the role of flow cytometry
Lymphoproliferative disorders are a heterogeneous group of malignant clonal proliferations of lymphocytes whose diagnosis remains challenging, despite diagnostic criteria are now well established, due to their heterogeneity in clinical presentation and immunophenotypic profile. Lymphoid T-cell disorders are more rarely seen than B-cell entities and more difficult to diagnose for the absence of a specific immunophenotypic signature. Flow cytometry is a useful tool in diagnosing T-cell lymphoproliferative disorders since it is not only able to better characterize T-cell neoplasms but also to resolve some very complicated cases, in particular those in which a small size population of neoplastic cells is available for the analysis. Here, we report three patients with mature T-cell neoplasms with atypical clinical and biological features in which analysis of peripheral blood and bone marrow specimens by means of multicolor flow cytometry was very useful to identify and characterize three rare T-cell lymphoproliferative disorders, such as angioimmunoblastic T-cell lymphoma, peripheral T-cell lymphoma not otherwise specified and T-cell prolym-phocytic leukemia. The aim of this case series report is not only to describe three rare cases of lymphoproliferative neoplasms but also to raise awareness that a fast, highly sensitive, and reproducible procedure, such as flow cytometry immunophenotyping, can have a determinant diagnostic role in these patients
Natural Variation in Decision-Making Behavior in Drosophila melanogaster
There has been considerable recent interest in using Drosophila melanogaster to investigate the molecular basis of decision-making behavior. Deciding where to place eggs is likely one of the most important decisions for a female fly, as eggs are vulnerable and larvae have limited motility. Here, we show that many natural genotypes of D. melanogaster prefer to lay eggs near nutritious substrate, rather than in nutritious substrate. These preferences are highly polymorphic in both degree and direction, with considerable heritability (0.488) and evolvability
Fire Fragility Curves for Industrial Steel Pipe-Racks Integrating Demand and Capacity Uncertainties
This paper aims at deriving fire fragility curves for a prototype steel pipe-rack in an industrial plant subjected to localised fires. In particular, starting from a reference case study, uncertainties related to the structural capacity and the size of the localised fires caused by a hole in a tank or a hole in a pipe are included in the analyses. Thus, the influence of uncertainties in the derivation of the fragility functions was highlighted by comparing four sets of analyses in which both demand and capacity uncertainties were progressively introduced. Moreover, alongside the cloud analysis (CA), the suitability of the multiple stripe analysis (MSA) to build relevant probabilistic fire demand models was assessed. Fire fragility curves were derived by considering the interstorey drift ratio (ISDR) as engineering demand parameter (EDP) and by assessing different relevant intensity measures (IMs) that represent the severity of localised fires. It was found that by introducing uncertainties in the steel yield strength, lower probabilities to exceed the life safety and the near collapse limit states with respect to the reference case study were observed. Moreover, the inclusion of further uncertainties, described with continuous physically-based probability functions of the size of the fire diameter, affected the probabilistic models by lowering the probability of exceedance. These functions provide a more realistic description of the fire scenario, enabling a better representation of the structural vulnerability. For this case study, the CA exhibited better suitability for the derivation of fire fragility curves than the MSA. All the analysis results are thoroughly discussed in the paper
Benefits of decreasing the uncertainty in the current bridge inspection practice
Numerous bridges worldwide have surpassed their service-life. To ensure the user safety, visual inspections are commonly carried out with the consequent assignment of Defect Grades. On their basis, simplified risk evaluations and maintenance intervention prioritization are formulated. Per the inherent nature of visual inspections, these ones include two kinds of uncertainty: interpretation-related and representation-related one. If to attempt to reduce their influence in the inspective process, the former, being an intrinsic feature of inspections performed by humans, could not be tackled. The latter, instead, can be decreased on the basis of a novel semantics-based inspective methodology. On the grounds of a large set of real-life inspections outputs, the present article measures the inspection quality improvement following said uncertainty reduction. This was achieved through the Expected Utility Theory in terms of utility and costs. On the grounds of these two, a novel Uncertainty-induced Cost curve allows the assessment of the cost evolution as a function of the weight of the representation-related uncertainty. The proposed semantics-based inspective methodology represents an improvement over the current-day directly assigned condition grading one, thus improving the efficiency of structural reliability assessments. This leads to an improved prioritization of bridge maintenance interventions and to an increased user safety
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