A time discretization scheme for a nonlocal degenerate problem modelling resistance spot welding

This is the author's PDF version of an article published in Mathematical Modelling of Natural Phenomena© 2015. The definitive version is available at http://www.mmnp-journal.org/articles/mmnp/abs/2015/06/mmnp2015106p90/mmnp2015106p90.htmlIn the current work we construct a nonlocal mathematical model describing the phase transition occurs during the resistance spot welding process in the industry of metallurgy. We then consider a time discretization scheme for solving the resulting nonlocal moving boundary problem. The scheme consists of solving at each time step a linear elliptic partial differential equation and then making a correction to account for the nonlinearity. The stability and error estimates of the developed scheme are investigated. Finally some numerical results are presented confirming the efficiency of the developed numerical algorithm

Optimal Control of Nonlocal Thermistor Equations

We are concerned with the optimal control problem of the well known nonlocal thermistor problem, i.e., in studying the heat transfer in the resistor device whose electrical conductivity is strongly dependent on the temperature. Existence of an optimal control is proved. The optimality system consisting of the state system coupled with adjoint equations is derived, together with a characterization of the optimal control. Uniqueness of solution to the optimality system, and therefore the uniqueness of the optimal control, is established. The last part is devoted to numerical simulations.Comment: Submitted 21-March-2012; revised 11-June-2012; accepted 13-June-2012; for publication in the International Journal of Contro

Painful Vaso-occlusive Crisis as a Prodromal Phase of Acute Chest Syndrome. Is Only One Chest X-ray Enough? A Case Report

The predominant pathophysiological feature of homozygous sickle cell anemia (SCA) is the vaso-occlusion. Vaso-occlusion can be associated with painful crises, which are the primary reason for those patients to seek medical care. Vaso-occlusion is responsible for the acute chest syndrome (ACS) with large morbidity and mortality or more rarely (and especially in adults) for priapism and acute neurological events (strokes). A 10-year-old boy with homozygous SCA was admitted to the Pediatric Emergencies with painful vaso-occlusive crisis and fever. Initially he had normal chest X-ray but, after 24-hour-hospitalization, he developed  ACS with new chest X-ray findings. He was treated with broad spectrum antibiotics, blood transfusions and bronchodilators and after a  six-day treatment, he was significantly improved. The patient was discharged 13 days later with no other therapy at home. The possibility of  ACS development should be still considered, even when a  known patient with SCA presents a  painful vaso-occlusive crisis with an initial normal chest X-ray. Therefore, repeated clinical examination is required and possible changes in  the clinical status could indicate the necessity of a  new radiographic examination. In  this way, early  ACS could be recognized and the catastrophic consequences due to this syndrome could be avoided

Analysis of biomass hydrothermal liquefaction and biocrude-oil upgrading for renewable jet fuel production: The impact of reaction conditions on production costs and GHG emissions performance

This paper shows a detailed analysis of a biomass HTL process by considering changes in three main reaction variables (i.e. catalysts (water, Na2CO3(aq.), and Fe(aq.)), temperature (280–340 °C), and catalysts/biomass mass ratio (0–0.33 kg catalysts/kg biomass)), and by assessing their influence on the techno-economic and GHG emissions performance. This analysis is based on Aspen Plus® simulations, process economics and life-cycle GHG assessment on SimaPro (using Ecoinvent 2.2). Results showed that the lowest production cost for biocrude oil is achieved when HTL is performed at 340 °C with Fe as catalyst (450 €/tbiocrude-oil or 13.6 €/GJbiocrude-oil). At these conditions, the biocrude oil produced has an oxygen content of 16.6 wt% and a LHV of 33.1 MJ/kgbiocrude-oil. When the hydrotreatment and hydrogen generation units are included, the total production costs was 1040 €/tupgraded-oil or 0.8 €/Lupgraded-oil. After fractionation, the estimated production cost was 1086 €/tbiojet-fuel or 25.1 €/GJbiojet-fuel. This value is twice the commercial price of fossil jet fuel. However, the allocated life cycle GHG emissions for renewable jet fuel were estimated at 13.1 kgCO2-eq./GJbiojet-fuel, representing only 15% the GHG emission of fossil jet fuel and therefore, indicating a significant potential on GHG emission reduction.BT/Biotechnology and Societ

Unnecessary diagnostic investigations in benign acute childhood myositis: A case series report

Benign acute childhood myositis (BACM) is a rare, acute, self-limiting muscle disorder, mainly affecting school-aged boys, with an excellent prognosis, requiring no therapeutic intervention. We report a series of seven previously healthy school-aged children with clinical and laboratory findings suggesting BACM where no specific diagnostic investigations were performed. All of the children were hospitalized without any specific therapeutic intervention and were discharged after two or three days free of symptoms, residual impairment or other complication. This report emphasizes that the correct diagnosis of BACM, by considering the characteristic clinical and laboratory findings of this syndrome and by recognizing more severe pathological conditions, which must be excluded from the diagnosis, can prevent unnecessary diagnostic investigations and reassure both parents and patients of the excellent prognosis

Radiology of the adrenal incidentalomas. Review of the literature

The term “adrenal incidentaloma” is a radiological term. Adrenal incidentalomas are adrenal tumors discovered in an imaging study that has been obtained for indications exclusive to adrenal conditions (Udelsman 2001; Linos 2003; Bulow et al. 2006; Anagnostis et al. 2009). This definition excludes patients undergoing imaging testing as part of staging and work-up for cancer (Grumbach et al. 2003; Anagnostis et al. 2009). Papierska et al. (2013) have added the prerequisite that the size of a tumor must be “greater than 1cm in diameter”, in order to be called incidentaloma. Although in the most cases these masses are non-hypersecreting and benign, they still represent an important clinical concern because of the risk of malignancy or hormone hyperfunction (Barzon et al. 2003). The adrenal tumors belong to the commonest incidental findings having been discovered (Kanagarajah et al. 2012). © 2017, De Gruyter Open Ltd. All rights reserved