A new approach for reverse analyses in depth-sensing indentation using numerical simulation

This paper seeks to present a new approach to reverse analysis in depth-sensing indentation which makes use of numerical simulation. This methodology allows the results of experimental hardness tests acquired with single indenter geometry to be used to determine the plastic properties of materials. Forward and reverse analyses of high deformation three-dimensional numerical simulations of Vickers indentation tests are used to determine different mechanical properties of materials: Young's modulus, yield stress and strain-hardening exponent. The Vickers indenter used in the numerical simulations is formulated as a rigid body and takes into account the presence of the most common imperfection of the tip, so-called offset. The contact friction between the Vickers indenter and the deformable body is also considered. The forward analysis uses materials with Young's modulus values from 50 to 600 GPa, yield stress values from 0.3 to 10 GPa and strain-hardening exponents from 0 to 0.6; the Poisson ratio did not vary from 0.3. The representative plastic strain [epsilon]r and the correspondent stress [sigma]r, as previously defined by other authors [Dao M, Chollacoop N, Vliet KJ, Venkatesh TA, Suresh S. Acta Mater 2001;49:3899], were identified by an independent numerical method. The values of the representative plastic strain [epsilon]r obtained for the Vickers indenter confirm those of the above-mentioned authors, despite showing a slight influence from the Young's modulus values. The forward study enables the production of a unique plot of the hardness HIT vs. representative stress [sigma]r, where both are normalized by the Young's modulus E. The proposed reverse analysis provides a unique solution to the representative stress [sigma]r and the strain-hardening exponent, n, given that the Young's modulus is predetermined from the experimental hardness test. Depending on the material properties, the value of n can be more or less sensitive to the scatter of the experimental results obtained using the depth-sensing equipment, particularly the stiffness of the unloading curve. The validity of the proposed reverse analysis method is checked using three real materials: stamping quality steel (DC 06), stainless AISI 304 steel and BK7 glass.http://www.sciencedirect.com/science/article/B6TW8-4M69JXG-1/1/ffe1726f3b7df73e4e01c941d6c4cbe

Material parameters identification: Gradient-based, genetic and hybrid optimization algorithms

This paper presents two procedures for the identification of material parameters, a genetic algorithm and a gradient-based algorithm. These algorithms enable both the yield criterion and the work hardening parameters to be identified. A hybrid algorithm is also used, which is a combination of the former two, in such a way that the result of the genetic algorithm is considered as the initial values for the gradient-based algorithm. The objective of this approach is to improve the performance of the gradient-based algorithm, which is strongly dependent on the initial set of results. The constitutive model used to compare the three different optimization schemes uses the Barlat'91 yield criterion, an isotropic Voce type law and a kinematic Lemaitre and Chaboche law, which is suitable for the case of aluminium alloys. In order to analyse the effectiveness of this optimization procedure, numerical and experimental results for an EN AW-5754 aluminium alloy are compared.http://www.sciencedirect.com/science/article/B6TWM-4SJGWMW-1/1/01e8be60ce61e8fc30473d85439fbe3

Children's sympathy, guilt, and moral reasoning in helping, cooperation, and sharing: a 6-year longitudinal study

This study examined the role of sympathy, guilt, and moral reasoning in helping, cooperation, and sharing in a 6-year, three-wave longitudinal study involving 175 children (Mage 6.10, 9.18, and 12.18 years). Primary caregivers reported on children's helping and cooperation; sharing was assessed behaviorally. Child sympathy was assessed by self- and teacher reports, and self-attributed feelings of guilt–sadness and moral reasoning were assessed by children's responses to transgression vignettes. Sympathy predicted helping, cooperation, and sharing. Guilt–sadness and moral reasoning interacted with sympathy in predicting helping and cooperation; both sympathy and guilt–sadness were associated with the development of sharing. The findings are discussed in relation to the emergence of differential motivational pathways to helping, cooperation, and sharing

Considerations for nutrition support in critically ill children with COVID-19 and paediatric inflammatory multisystem syndrome temporally associated with COVID-19

The aim of this editorial is to provide an adaptation of nutrition support recommendations for the overall population of critically ill children, to provide further refined recommendations for critically ill children presenting with COVID-19 or paediatric hyper-inflammatory syndrome temporally associated with COVID-19. They are based on the ESPNIC-MEN section recommendations published in January 2020 (6) and Surviving Sepsis Campaign recommendations from February 2020 (7). These recommendations cover the acute, stable and rehabilitation phases (Table 1, Table 2)

Necrotizing entercolitis: socio-demographic, clinical and histopathological findings in a series of neonatal autopsies

La enterocolitis necrotizante es un trastorno caracterizado por la necrosis isquémica de la mucosa intestinal, es la enfermedad gastrointestinal más grave que afecta a los neonatos, con alta morbilidad y mortalidad, principalmente en prematuros. El objetivo del presente estudio es describir las características clínicas y anatomopatológicas de los recién nacidos fallecidos con enterocolitis necrotizante, diagnosticados en un hospital de alta complejidad. Metodología. Este es un estudio descriptivo retrospectivo de 21 casos de autopsias médico-científicas hechas en un hospital de alta complejidad del nororiente colombiano, con hallazgos anatomopatológicos de enterocolitis necrotizante, realizadas entre enero de 2013 y julio de 2017. Resultados. El 85.7% de los recién nacidos eran pretérminos, un igual porcentaje presentaba un peso menor a 2,500 gramos al nacer. Respecto a los antecedentes maternos el 14.3% tuvieron espectro de trastornos hipertensivos asociados al embarazo y el 23.8% infección materna. Los tres sitios más frecuentes de ubicación de enterocolitis necrotizantes fue íleon, colon ascendente y colon transverso. Discusión. Según algunos autores, hasta el 85% de todos los casos de enterocolitis necrotizante ocurren en pacientes prematuros, especialmente en bebés con peso extremadamente bajo al nacer. Hay formas de enterocolitis necrotizante que ocurren en bebés a término y, generalmente, están asociadas con factores predisponentes, resultados compatibles con lo que encontramos en esta investigación. Conclusiones. Este estudio elaborado con población colombiana se correlaciona con lo descrito en la población mundial en la cual la enterocolitis necrotizante se presenta más en los recién nacidos pretérmino y con bajo peso al nacer.Necrotizing entercolitis is a disorder characterized by the ischemic necrosis of intestinal mucosa. It is the most serious gastrointestinal disease affecting neonates, with high morbidity and mortality rates, mainly among premature newborns. The purpose of this study is to describe the clinical and anatamo-pathological characteristics of deceased newborns with necrotizing entercolitis, diagnosed at a high-complexity hospital. Methodology. This is a descriptive retrospective study of 21 cases of medical-scientific autopsies performed at a high-complexity hospital in northeastern Colombia, with anatomo-pathological findings of necrotizing entercolitis, performed between January 2013 and July 2017. Results. 85.7% of the newborns were pre-term, and the same percentage had weight at birth below 2.5 kilograms. Regarding the mothers’ background, 14.3% displayed a spectrum of hypertensive disorders associated with pregnancy, and 23.8% had maternal infections. The three most frequent locations of necrotizing entercolitis were the ileum, ascending colon and transverse colon. Discussion. According to some authors, up to 85% of all cases of necrotizing entercolitis occur in premature patients, especially in babies with extremely low weight at birth. There are forms of necrotizing entercolitis that occur in full term babies, and they are generally associated with contributing factors, which is consistent with the findings of this study. Conclusions. This study of a Colombian population is consistent with other descriptions of the global population, where necrotizing entercolitis arises more frequently in pre-term newborns and low weight at birth

PIH11 out-of-pocket health expenditures related to prenatal care: evidence from Colombia, 2018

To estimate the out-of-pocket expenditures (OOPE) and indirect costs related to prenatal check-ups and pregnancy complications in women seen in a maternity hospital in Cartagena-Colombia, 2018. Cost description study. A survey was constructed to estimate OOPE and indirect costs owing to prenatal check-ups. Women were asked about sociodemographic variables. The survey investigated how much pregnant women spend in the care of prenatal check-ups. Also, it explored OOPE linked to pregnancy complications. Productivity losses were quantified from the reduction of work time produced by the prenatal check-up. Absolute and relative frequencies, averages and interquartile ranges (IQR) were used to describe the population and estimate the OOPE and indirect costs in pregnant women. The latter were calculated from the percentile method. We performed a bootstrapping to generate an empirical estimate of the complete sample distribution. Costs were reported in Colombian pesos (COP), 2018. Fifty-six pregnant women were surveyed, with an average age of 25.9 years (±6.2). 96.4% of the respondents had completed at least primary school studies, 7.3% were married. All women surveyed had OOPE in at least one cost-item. Transportation was the item with the highest frequency of expenses. The mean of OOPE for women who attend their prenatal check-up were COP$71,736 (IQR COP$53,400-$92,715). Twenty-five women reported some complication related to their pregnancy status. The mean OOPE associated with a pregnancy complication was COP$57,539 (IQR COP$28,686-$100,124). Women reported a time average of 4.2 hours (range 1-12) for attending the prenatal check-up, and their companions spent 4.5 (range 1-13). On average a woman had productivity losses of COP$13,541 (IQR COP$8,138- $16,276) and her companion COP$14,475 (range $8,130-$19,531). Expenses produced by prenatal care could totalize 9.2% (6.8-11.9) of the monthly income of a poor household, which unfortunately makes prenatal care an important source of economic burden, impacting poor population in Cartagena

Simulation of the CMS Resistive Plate Chambers

The Resistive Plate Chamber (RPC) muon subsystem contributes significantly to the formation of the trigger decision and reconstruction of the muon trajectory parameters. Simulation of the RPC response is a crucial part of the entire CMS Monte Carlo software and directly influences the final physical results. An algorithm based on the parametrization of RPC efficiency, noise, cluster size and timing for every strip has been developed. Experimental data obtained from cosmic and proton-proton collisions at $\sqrt{s}=7$ TeV have been used for determination of the parameters. A dedicated validation procedure has been developed. A good agreement between the simulated and experimental data has been achieved.Comment: to be published in JINS

GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP

Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension of fast simulation approaches to more use cases, covering a larger fraction of the simulation budget, is only part of the solution due to intrinsic precision limitations. The remainder corresponds to speeding-up the simulation software by several factors, which is out of reach using simple optimizations on the current code base. In this context, the GeantV R&D project was launched, aiming to redesign the legacy particle transport codes in order to make them benefit from fine-grained parallelism features such as vectorization, but also from increased code and data locality. This paper presents extensively the results and achievements of this R&D, as well as the conclusions and lessons learnt from the beta prototype.Comment: 34 pages, 26 figures, 24 table

Radiation background with the CMS RPCs at the LHC

The Resistive Plate Chambers (RPCs) are employed in the CMS Experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This article presents results of the radiation background measurements performed with the 2011 and 2012 proton-proton collision data collected by CMS. Emphasis is given to the measurements of the background distribution inside the RPCs. The expected background rates during the future running of the LHC are estimated both from extrapolated measurements and from simulation