Generic techno-economic optimization methodology for concurrent design and operation of solvent-based PCC processes

© 2020 Elsevier Ltd A techno-economic equation-based methodology is developed for optimal design and operation of integrated solvent-based post-combustion carbon capture (PCC) processes using a rate-based model for the interaction of gas and liquid. The algorithm considers a wide range of techno-economic design and operation parameters such as number of absorber/desorber columns, height of columns, diameter of columns, operating conditions (P, T) of columns, pressure drop, packing type, percentage of CO2 mitigated, captured CO2 purity, amount of solvent regeneration, flooding velocities of columns, and number of compression stages. A case study is conducted to showcase two common objective-functions i) minimizing total capital investment, and ii) minimizing levelized capture costs, both for a 300 MW coal-power plant in Australia. The former objective leads to the lowest possible total capital cost of $312.4 M corresponding to levelized carbon capture cost of 58.1$/tonne−CO2. For objective (ii), however, the lowest levelized carbon capture cost is found to be around ten percent lower (52.8 $/tonne−CO2), though it leads to a higher total capital cost ($325.2 M). The results indicate that the design and operation variables are markedly interactive, and no unique optimal design exists which can deliver all desired outcomes at once. Therefore, decisions on the selection of right variables become dependent on the decision-makers techno-economic objectives

New insights into perinatal testicular torsion

Perinatal testicular torsion is a relatively rare event that remains unrecognized in many patients or is suspected and treated accordingly only after an avoidable loss of time. The authors report their own experience with several patients, some of them quite atypical but instructive. Missed bilateral torsion is an issue, as are partial torsion, possible antenatal signs, and late presentation. These data are discussed together with the existing literature and may help shed new light on the natural course of testicular torsion and its treatment. The most important conclusion is that a much higher index of suspicion based on clinical findings is needed for timely detection of perinatal torsion. It is the authors’ opinion that immediate surgery is mandatory not only in suspected bilateral torsions but also in cases of possible unilateral torsions. There is no place for a more fatalistic “wait-and-see” approach. Whenever possible, even necrotic testes should not be removed during surgery because some endocrine function may be retained

Hydrogen as an energy vector

© 2019 Elsevier Ltd Hydrogen is known as a technically viable and benign energy vector for applications ranging from the small-scale power supply in off-grid modes to large-scale chemical energy exports. However, with hydrogen being naturally unavailable in its pure form, traditionally reliant industries such as oil refining and fertilisers have sourced it through emission-intensive gasification and reforming of fossil fuels. Although the deployment of hydrogen as an alternative energy vector has long been discussed, it has not been realised because of the lack of low-cost hydrogen generation and conversion technologies. The recent tipping point in the cost of some renewable energy technologies such as wind and photovoltaics (PV) has mobilised continuing sustained interest in renewable hydrogen through water splitting. This paper presents a critical review of the current state of the arts of hydrogen supply chain as a forwarding energy vector, comprising its resources, generation and storage technologies, demand market, and economics

Chronic neurological complications in hemolytic uremic syndrome in children

Introduction. Central nervous system (CNS) involvement is the most common extrarenal involvement in hemolytic uremic syndrome (HUS). There are limited reports on clinical cause of chronic neurologic problems in HUS. We evaluated residual neurologic involvement in children with HUS. Materials and Methods. This cross-sectional study was conducted on 58 patients with a diagnosis of HUS referred to 2 tertiary pediatric centers. Neurological examinations was performed on all of the patients and they were followed up between 2001 and 2015. Data including demographic variables, type of HUS, neurological symptoms, and other complications were recorded. Neurological involvements that occurred after 6 months from the acute phase of HUS were considered as chronic neurological involvement. Results. Among 58 patients who were included in the study, 31 (53.4) had neurological manifestations (31 with acute and 19 with chronic complications). There was no significant difference in acute neurological manifestations between typical and atypical HUS, while chronic neurological manifestations were more frequents in patients with atypical HUS (P =.05). The most common presentations were seizure and decreased level of consciousness. Chronic neurologic problems were found in follow-up visits of 11 patients with acute and 8 without acute involvement. Hypertension was associated with chronic manifestations (P =.01). Conclusions. According to our results, residual neurological problems were not infrequent in HUS and they were more related with atypical form of disease. Evidence of hypertension is a significant variable for persistence of neurologic problems. © 2019, Iranian Society of Nephrology. All rights reserved

Escroto agudo

Este artigo pretende fazer uma revisão geral do tema, com ênfase em conceitos atuais e/ou controversos no manejo das situações clínicas em questão, em especial conceitos ainda polêmicos quanto à fisiopatologia e ao manejo diagnóstico. Também é feita uma revisão extensa quanto aos aspectos clínicos e terapêuticos da torção de testículo neonatal e quanto aos aspectos de diagnóstico diferencial na síndrome do escroto agudo. São citadas informações estatísticas derivadas dos principais estudos clínicos publicados nos últimos 20 anos em literatura médica ocidental