Computational Homogenization of Architectured Materials

Architectured materials involve geometrically engineered distributions of microstructural phases at a scale comparable to the scale of the component, thus calling for new models in order to determine the effective properties of materials. The present chapter aims at providing such models, in the case of mechanical properties. As a matter of fact, one engineering challenge is to predict the effective properties of such materials; computational homogenization using finite element analysis is a powerful tool to do so. Homogenized behavior of architectured materials can thus be used in large structural computations, hence enabling the dissemination of architectured materials in the industry. Furthermore, computational homogenization is the basis for computational topology optimization which will give rise to the next generation of architectured materials. This chapter covers the computational homogenization of periodic architectured materials in elasticity and plasticity, as well as the homogenization and representativity of random architectured materials

Risk assessment of accidental exposure of surgeons to blood during orthopedic surgery. Are we safe in surgical gloves?

Aim. To analyze tears in sterile surgical gloves used by surgeons in the operating theatre of the Trauma and Orthopedic Surgery Department, Copernicus Memorial Hospital, Łódź, Poland Materials and Method. This study analyzes tears in sterile surgical gloves used by surgeons by ICD-9 and ICD-10 codes. 1,404 gloves were collected from 581 surgical procedures. All gloves were tested immediately following surgery using the test method described in Standard EN455–1 (each glove was inflated with 1,000 ± 50 ml of water and observed for leaks for 2–3 min.). Results. Analysis of tears took into consideration the role of medical personnel (operator, first assistant, second assistant) during surgical procedure, the type of procedure according to ICD-9 and ICD-10 codes, and the elective or emergency nature of the procedure. The results of the study show that these factors have a significant influence on the risk of glove tears. Significant differences were observed in tear frequency and tear location depending on the function performed by the surgeon during the procedure. Conclusion. The study proved that the role performed by the surgeon during the procedure (operator, first assistant, second assistant) has a significant influence on the risk of glove tearing. The role in the procedure determines exposure to glove tears. Implementing a double gloving procedure in surgical procedures or using single gloves characterized by higher tear resistance should be considered

Comparison of indicators of the use of insulin and oral diabetes medication in a Polish population of patients in urban and rural areas in the years 2008, 2011 and 2012

introduction. Diabetes is one of the 10 most important chronic diseases in the world. According to the data of the International Diabetes Federation, in Poland 9% of the population between the ages of 20–79 suffer from diabetes. objective. The aim of this study was to investigate the differences in the prevalence of diabetes in urban and rural areas in Poland, and the preparation of a model describing the phenomenon. materials and method. Differences between urban and rural areas were studied for the occurrence of patients treated with diabetes per 100,000 inhabitants, the number of patients, structure of treatment per the used products, and the costs of reimbursement of treatment products between 2008–2012. Urban and rural cases were compared using zip codes. The basis for classifying a patient as being an inhabitant of an urban or rural area was an urban zip code of the declared place of residence. results. Differences were observed both between various areas of Poland, as well as depending on whether the declared place of residence of the patient was urban or rural. Differences between urban and rural areas within the studied period have increased. The difference in the prevalence of diabetes among the inhabitants of Podlaskie, Śląskie or Świętokrzyskie provinces is striking. conclusion. Differences between urban and rural areas which depend on morbidity and detection of patients in the earlier phase of illness, the structures of medical technologies used in the treatment process, the number of purchased pharmaceuticals, enable better monitoring of effectiveness and quality of politics on prevention and treatment of chronic diseases. It is important for the creation of a health policy to devise a system of indicators, which will enable a decrease in the existing differences between regions, and between the urban and rural areas within the provinces

Lithiation of ramsdellite-pyrolusite MnO \u3c inf\u3e 2 ; NMR, XRD, TEM and electrochemical investigation of the discharge mechanism

Electrolytic manganese dioxide (EMD) is made in aqueous sulfuric acid and neutralized or ion exchanged with aqueous lithium hydroxide before use in Li batteries. Solid state Li NMR studies show that Li is present on surface and vacancy sites and migrates into Mn (III) related sites after heat treatment to remove water. During heat treatment the MnO2 rearranges from ramsdellite/pyrolusite intergrowth EMD to a defect pyrolusite heat-treated manganese dioxide (HEMD). EMD exhaustively treated with lithium hydroxide solution has 40-50% of the protons in EMD exchanged for Li ions to produce a structurally unchanged γ-MnO2. Li magic angle spinning (MAS) NMR reveals that this lithiated material contains lithium in cation vacancy and Mn (III) related sites in the MnO2 lattice in addition to ionic Li on the surface. During heat treatment, the vacancy lithium content prevents the ramsdellite to pyrolusite rearrangement in HEMD formation. Instead, an ordered ramsdellite/pyrolusite intergrowth of lithiated manganese dioxide (LiMD) is formed with an approximate composition of 50% ramsdellite and 50% pyrolusite. Li MAS NMR of LiMD shows Li resonances near 280 and 560 ppm, consistent with Li transition from surface and cation vacancy sites into the ramsdellite lattice. LiMD discharged against lithium shows two processes, one near 3.1 V, the other about 2.8 V. Li MAS NMR studies show the initial reduction results a lithium resonance near 560 ppm associated with Li near a mixed valence Mn (III/IV) environment followed by appearance of a resonance near 100 ppm consistent with a Li environment near Mn (III). TEM studies of the reduced material show initial expansion of the ramsdellite lattice accompanied by a loss in crystallinity in the 3.1 V discharge process followed by disappearance of the pyrolusite content via conversion to ramsdellite in the second discharge process. © 2005 Elsevier B.V. All rights reserved