Integration of physical operations in the hydrometallurgical processing of spent Zn-MnO2 batteries

The recycling of spent Zn-MnO2 batteries by hydrometallurgy involves the leaching of material previously treated by physical processing to allow the liberation of electrode particles and the separation of unwanted scrap. The integration of these physical operations with leaching is therefore crucial for the optimization of the process, allowing achieving high recovery yields of zinc and manganese and minimizing reactants consumption and iron contamination. In this paper, several options involving physical processing and leaching with sulphuric acid are presented and discussed. After batteries shredding and disaggregation, the separation of steel scrap was performed by sieving or magnetic separation, and the remaining solids were treated by leaching. These options were compared, in terms of metals recovery and contamination, with the alternative of direct leaching of all the shredded fractions without physical treatment. The separation of the steel scrap by sieving or magnetic separation allowed the removal from the circuit of 37 or 49% of iron, respectively, with losses of 15 or 6% of zinc and 2 or 4% of manganese. Therefore more than 50% of iron remained in the process, which was attributed to the presence of iron oxides formed by the corrosion of the battery cases. In the leaching operation, zinc dissolution was very effective (yields above 97%) while manganese is strongly depended from the process option, being its leaching proportional to the presence of scrap (yields of 80%, 56% and 43%, respectively in direct leaching, sieving / leaching and magnetic separation / leaching). These results showed that iron plays an important role in the reductive leaching of manganese species (III or IV), and so the presence of steel scrap in leaching, besides disadvantages concerning solutions contamination, contributes positively for the leaching efficienc

The Nobel Prize In Chemistry 2016: Molecular Machines

The Nobel Prize in Chemistry 2016 was granted to Jean-Pierre Sauvage, Sir James F. Stoddart and Bernard (Ben) L. Feringa. These scientists were responsible for the creation and development of molecular machines. The development of such systems represents a breakthrough in the field of supramolecular chemistry, nanotechnology and organic synthesis. This article aims to bring simple and objective information to the scientific community about the work of these three researchers.40111312

The Nobel Prize in Chemistry 2016: molecular machines

The Nobel Prize in Chemistry 2016 was granted to Jean-Pierre Sauvage, Sir James F. Stoddart and Bernard (Ben) L. Feringa. These scientists were responsible for the creation and development of molecular machines. The development of such systems represents a breakthrough in the field of supramolecular chemistry, nanotechnology and organic synthesis. This article aims to bring simple and objective information to the scientific community about the work of these three researchers.The Nobel Prize in Chemistry 2016 was granted to Jean-Pierre Sauvage, Sir James F. Stoddart and Bernard (Ben) L. Feringa. These scientists were responsible for the creation and development of molecular machines. The development of such systems represents401113123sem informaçãosem informaçã

Comparison of production strategies and degree of postponement when incorporating additive manufacturing to product supply chains

The best-selling products manufactured nowadays are made in long series along rigid product value chains. Product repetition and continuous/stable manufacturing is seen as a chance for achieving economies of scale. Nevertheless, these speculative strategies fail to meet special customer demands, thus reducing the effective market share of a product in a range. Additive Manufacturing technologies open promising product customization opportunities; however, to achieve it, it is necessary to delay the production operations in order to incorporate the customer’s inputs in the product materialization. The study offered in the present paper compares different possible production strategies for a product (via conventional technologies and Additive Manufacturing) and assesses the degree of postponement that it would be recommended in order to meet a certain demand distribution. The problem solving is calculated by a program containing a stochastic mathematical model which incorporates extensive information on costs and lead times for the required manufacturing operations.Postprint (published version

Basketball game-related statistics that discriminate between teams season-long success

The aim of the present study was to identify the game-related statistics that discriminate between season-long successful and unsuccessful basketball teams participating in the Spanish Basketball League (LEB1). The sample included all 145 average records per season from the 870 games played between the 2000-2001 and the 2005-2006 regular seasons. The following game-related statistics were gathered from the official box scores of the Spanish Basketball Federation: 2- and 3-point field-goal attempts (both successful and unsuccessful), free-throws (both successful and unsuccessful), defensive and offensive rebounds, assists, steals, turnovers, blocks (both made and received), and fouls (both committed and received). To control for season variability, all results were normalized to minutes played each season and then converted to z-scores. The results allowed discrimination between best and worst teams' performances through the following game-related statistics: assists (SC=0.47), steals (SC=0.34), and blocks (SC=0.30). The function obtained correctly classified 82.4% of the cases. In conclusion, season-long performance may be supported by players' and teams' passing skills and defensive preparation

Reference database of total retinal vessel surface area derived from volume-rendered optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) enables three-dimensional, high-resolution, depth-resolved flow to be distinguished from non-vessel tissue signals in the retina. Thus, it enables the quantification of the 3D surface area of the retinal vessel signal. Despite the widespread use of OCTA, no representative spatially rendered reference vessel surface area data are published. In this study, the OCTA vessel surface areas in 203 eyes of 107 healthy participants were measured in the 3D domain. A Generalized Linear Model (GLM) model analysis was performed to investigate the effects of sex, age, spherical equivalent, axial length, and visual acuity on the OCTA vessel surface area. The mean overall vessel surface area was 54.53 mm2 (range from 27.03 to 88.7 mm2). OCTA vessel surface area was slightly negatively correlated with age. However, the GLM model analysis identified axial length as having the strongest effect on OCTA vessel surface area. No significant correlations were found for sex or between left and right eyes. This is the first study to characterize three-dimensional vascular parameters in a population based on OCTA with respect to the vessel surface area

Civilising the natives? Liberal studies in further education revisited

This paper uses Basil Bernstein’s work on pedagogic discourses to examine a largely neglected facet of the history of vocational education – the liberal studies movement in English further education (FE) colleges. Initially, the paper discusses some of the competing conceptions of education, work and society which underpinned the rise and fall of the liberal studies movement – if indeed it can be described as such. It then draws on data from interviews with former liberal and general studies (LS/GS) lecturers to focus on the ways in which different variants of liberal studies were, over time, implicated in inculcating certain forms of knowledge in vocational learners. Whilst it is acknowledged that LS/GS always represented contested territory and that it was highly variable both in terms of content and quality, the paper argues that, at least and under certain circumstances, liberal studies provided young working-class people with the opportunity to locate their experiences of vocational learning within a critical framework which is largely absent from FE today. This, it is argued, can be conceptualised as an engagement with what Bernstein described as ‘powerful knowledge’

Management of Portal Hypertension in Children

Management of portal hypertension in children has evolved over the past several decades. Portal hypertension can result from intrahepatic or extrahepatic causes. Management should be tailored to the child based on the etiology of the portal hypertension and on the functionality of the liver. The most serious complication of portal hypertension is gastroesophageal variceal bleeding, which has a mortality of up to 30%. Initial treatment of bleeding focuses on stabilizing the patient. Further treatment measures may include endoscopic, medical, or surgical interventions as appropriate for the child, depending on the cause of the portal hypertension. β-Blockers have not been proven to effectively prevent primary or secondary variceal bleeding in children. Sclerotherapy and variceal band ligation can be used to stop active bleeding and can prevent bleeding from occurring. Transjugular intrahepatic portosystemic shunts and surgical shunts may be reserved for those who are not candidates for transplant or have refractory bleeding despite medical or endoscopic treatment

What is the value of orthodontic treatment?

Orthodontic treatment is as popular as ever. Orthodontists frequently have long lists of people wanting treatment and the cost to the NHS in England was £258m in 2010-2011 (approximately 10% of the NHS annual spend on dentistry). It is important that clinicians and healthcare commissioners constantly question the contribution of interventions towards improving the health of the population. In this article, the authors outline some of the evidence for and against the claims that people with a malocclusion are at a disadvantage compared with those without a malocclusion and that orthodontic treatment has significant health benefits. The authors would like to point out that this is not a comprehensive and systematic review of the entire scientific literature. Rather the evidence is presented in order to stimulate discussion and debate