On the evolution of the entropy and pressure profiles in X-ray luminous galaxy clusters at z > 0.4

Galaxy clusters are the most recent products of hierarchical accretion over cosmological scales. The gas accreted from the cosmic field is thermalized inside the cluster halo. Gas entropy and pressure are expected to have a self-similar behaviour with their radial distribution following a power law and a generalized Navarro-Frenk-White profile, respectively. This has been shown also in many different hydrodynamical simulations. We derive the spatially-resolved thermodynamical properties of 47 X-ray galaxy clusters observed with Chandra in the redshift range 0.4 < z < 1.2, the largest sample investigated so far in this redshift range with X-rays spectroscopy, with a particular care in reconstructing the gas entropy and pressure radial profiles. We search for deviation from the self-similar behaviour and look for possible evolution with redshift. The entropy and pressure profiles lie very close to the baseline prediction from gravitational structure formation. We show that these profiles deviate from the baseline prediction as function of redshift, in particular at z > 0.75, where, in the central regions, we observe higher values of the entropy (by a factor of 2.2) and systematically lower estimates (by a factor of 2.5) of the pressure. The effective polytropic index, which retains informations about the thermal distribution of the gas, shows a slight linear positive evolution with the redshift and the concentration of the dark matter distribution. A prevalence of non-cool-core, disturbed systems, as we observe at higher redshifts, can explain such behaviours.Comment: 14 pages, 18 figures, accepted for publication by A&

Mechanical Behavior of Gas Metal Arc Welds and Lithium-Ion Battery Modules.

The first part of the dissertation is related to a study of the failure mechanisms of gas metal arc welds. Cost savings can be gained by minimizing the weld length. However, improperly sized welds can result in the loss of structural integrity of the welded components. The necking/shear failure modes for the mid-sections of gas metal arc welds in lap-shear specimens of HSLA steel are investigated. Three-dimensional finite element models were developed with the geometric characteristics of the heat affected zones (HAZ) designed to match the micrographs of the cross sections for the welds. The distributions of the void volume fraction near the welds shown from the finite element analyses are consistent with the failure modes observed in the experiments. Further finite element analyses showed that the geometric characteristics of the HAZ are key factors for the resulting failure location. The mode I and mode II stress intensity factor (SIF) solutions for gas metal arc welds in lap-shear specimens are investigated by the analytical solutions and by finite element analyses. The computational results indicate that the SIF solutions for realistic welds are lower than the analytical solutions for idealized weld geometry. Further finite element analyses were carried out in order to obtain the computational SIF solutions for the realistic weld geometries with dissimilar sheet thicknesses. Finally, three-dimensional computational results indicate that the distributions of the SIF solutions for discontinuous welds are different from those for continuous welds. In the second part, a computational model is developed for simulations of representative volume element specimens of lithium-ion battery modules under in-plane constrained compression tests. The model allows for computational efficiency while simulating the overall mechanical response of battery modules and the deformation patterns of the heat dissipater. The model is based on the properties of the heat dissipater, the foam, and the macro behavior of the cell components. The computational results compare fairly well with the experimental results. Further finite element analyses showed the increase in the initial nominal buckling stress under dynamic loading conditions.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111520/1/aed_1.pd

Effective resolution concepts for lidar observations

Abstract. Since its establishment in 2000, EARLINET (European Aerosol Research Lidar NETwork) has provided, through its database, quantitative aerosol properties, such as aerosol backscatter and aerosol extinction coefficients, the latter only for stations able to retrieve it independently (from Raman or high-spectral-resolution lidars). These coefficients are stored in terms of vertical profiles, and the EARLINET database also includes the details of the range resolution of the vertical profiles. In fact, the algorithms used in the lidar data analysis often alter the spectral content of the data, mainly acting as low-pass filters to reduce the high-frequency noise. Data filtering is described by the digital signal processing (DSP) theory as a convolution sum: each filtered signal output at a given range is the result of a linear combination of several signal input data samples (relative to different ranges from the lidar receiver), and this could be seen as a loss of range resolution of the output signal. Low-pass filtering always introduces distortions in the lidar profile shape. Thus, both the removal of high frequency, i.e., the removal of details up to a certain spatial extension, and the spatial distortion produce a reduction of the range resolution. This paper discusses the determination of the effective resolution (ERes) of the vertical profiles of aerosol properties retrieved from lidar data. Large attention has been dedicated to providing an assessment of the impact of low-pass filtering on the effective range resolution in the retrieval procedure

Minority Stress, Resilience, and Mental Health: A Study of Italian Transgender People

Transgender people often experience oppression because of gender nonconformity. They represent an extremely stigmatized population at high risk of developing mental health problems. The minority stress model is a theoretical model used to understand social stigma as a potential cause of mental health disparities faced by the transgender population. In Italy, studies applying this model to the transgender population are limited. The current study applied the minority stress model to a sample of Italian transgender people (n = 149), analyzing effects of prejudice events, expectations of rejection, and internalized transphobia, and their interaction with protective factors (resilience and social support), on mental health. The results suggest that exposure to everyday discrimination and internalized transphobia are associated with increased mental health problems, while perceived social support from family and resilience significantly reduced the strength of association between everyday discrimination and mental health. Findings have important implications for both social issues and policies

Low-Velocity Impacts on a Polymeric Foam for the Passive Safety Improvement of Sports Fields: Meshless Approach and Experimental Validation

Over the past few years, foam materials have been increasingly used in the passive safety of sport fields, to mitigate the risk of crash injury. Currently, the passive safety certification process of these materials represents an expensive and time-consuming task, since a considerable number of impact tests on material samples have to be carried out by an ad hoc testing apparatus. To overcome this difficulty and speed up the design process of new protective devices, a virtual model for the low-velocity impact behaviour of foam protective mats is needed. In this study a modelling approach based on the mesh-free Element Galerkin method was developed to investigate the impact behaviour of ethylene-vinyl acetate (EVA) foam protective mats. The main advantage of this novel technique is that the difficulties related to the computational mesh distortion and caused by the large deformation of the foam material are avoided and a good accuracy is achieved at a relatively low computational cost. The numerical model was validated statistically by comparing numerical and experimental acceleration data acquired during a series of impact events on EVA foam mats of various thicknesses. The findings of this study are useful for the design and improvement of foam protective devices and allow for optimizing sports fields’ facilities by reducing head injury risk by a reliable computational method

One year of tropospheri clidar measurements of aerosol extinction and backscatter

The aerosol lidar system operational at IMAA-CNR in Tito Scalo (PZ) (Southern Italy, 40°36'N, 15°44'E, 820 m above sea level) is part of the EARLINET project. Systematic lidar measurements of aerosol backscatter and extinction in the troposphere have been performed since May 2000. Aerosol backscatter measurements were performed at both 355 nm and 532 nm, while aerosol extinction coeffi cient were retrieved from simultaneous N2 Raman backscatter signals at 386.6 nm. The observations were performed on a regular schedule of two night time measurements per week (around sunset) and one daytime measurement per week (around 13:00 UTC). Furthermore, special observations concerning Saharan dust outbreaks have been carried out. Starting in May 2000 the lidar measurements performed in Tito Scalo have been collected and analysed. Preliminary results regarding the fi rst year of measurements are reported. In particular, the evolution of the aerosol integrated backscatter and extinction as well as of the mean value of the lidar ratio in the whole aerosol layer is reported. Results show clear evidence of seasonal variation of the observed parameters, with higher values and greater variability during summertime

Contributions of implicit memory strategies to the rehabilitation of an amnesic patient: case report

Even severe amnesic patients usually are able to learn new information using implicit memory strategies. In the present study we describe our experience in the rehabilitation of an amnesic patient who had suffered cerebral anoxia. He was taught to use a computer text editor, enabling him to sheltered work. The training program lasted 14 weeks and was based on errorless learning and drilling practice techniques. The patient succeeded in all tasks, even though he could not remember accurately the training sessions. These results meet previous studies which point out that interaction between implicit and residual explicit memory can provide a basis new learning in amnesic patients. The domain-specific knowledge acquisition is demonstrating effectiveness in neuropsychological rehabilitation of brain injured patients.Mesmo pacientes severamente amnésticos são capazes de aprender informações novas, apoiados em estratégias de memória implícita. No presente estudo descrevemos uma experiência de reabilitação neuropsicológica, em que um paciente amnéstico, portador de lesão cerebral por anóxia, foi submetido a treino para uso de computador, visando sua capacitação semi-profissional. O treinamento teve duração de 14 semanas, e as técnicas de ensino utilizadas foram a prática repetitiva e a aprendizagem sem erros. O paciente obteve sucesso na realização das tarefas propostas, aprendendo a operar um editor de textos e mantendo o aprendizado após a passagem do tempo. Apesar disso, lembrava-se apenas vagamente da situação de aprendizagem. O presente estudo corrobora trabalhos anteriores que observam a interação entre mecanismos de memória implícita e resíduos de memória explícita operando na aquisição de conhecimentos em pacientes amnésticos. A aprendizagem de conhecimentos específicos vem se mostrando eficiente para a reabilitação de pacientes que sofreram lesões cerebrais.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicobiologiaUNIFESP, EPM, Depto. de PsicobiologiaSciEL