48V battery testing and analysis for TLC applications

openThe purpose of this master thesis, in collaboration with Fiamm Energy Technology Spa, is to analyze and evaluate different 48V Lithium-ion batteries for telecom applications. Due to non-disclosure agreements between Fiamm and the different suppliers, the names of these producers cannot be shared so, in order to identify them, a number was assigned. In order to detect the best battery, the internal design and the electrical performances of each one were analyzed. For time constrains, only three batteries have been analyzed in details during the internship thesis. In the first part of the document the purpose of the project from the company point of view and a description of the lithium-ion battery technology are explained. After that, there is a description of the instruments utilized and an explanation of the various tests performed. The second part describes the teardown of three batteries and the results of the electrical tests. After that, a comparison between the different batteries was performed from design, electrical performances and software point of view, in order to determine the best one. The design comparison is based on the main design features of the batteries like the components of the BMS, the cable management and the cells arrangement. Instead, the electrical performances comparison takes into account the most critical characteristics like the capacity discharged, the maximum charge/discharge rate and the safety functions of the BMS. The comparisons mentioned above are based on the three batteries deeply analysed in this thesis and on others five analysed by Fiamm project team. Nowadays, supplier n.8 appears to be the best one. Fiamm has planned to evaluate other two batteries within the next months so the partial result obtained in this thesis could be different from the final one.The purpose of this master thesis, in collaboration with Fiamm Energy Technology Spa, is to analyze and evaluate different 48V Lithium-ion batteries for telecom applications. Due to non-disclosure agreements between Fiamm and the different suppliers, the names of these producers cannot be shared so, in order to identify them, a number was assigned. In order to detect the best battery, the internal design and the electrical performances of each one were analyzed. For time constrains, only three batteries have been analyzed in details during the internship thesis. In the first part of the document the purpose of the project from the company point of view and a description of the lithium-ion battery technology are explained. After that, there is a description of the instruments utilized and an explanation of the various tests performed. The second part describes the teardown of three batteries and the results of the electrical tests. After that, a comparison between the different batteries was performed from design, electrical performances and software point of view, in order to determine the best one. The design comparison is based on the main design features of the batteries like the components of the BMS, the cable management and the cells arrangement. Instead, the electrical performances comparison takes into account the most critical characteristics like the capacity discharged, the maximum charge/discharge rate and the safety functions of the BMS. The comparisons mentioned above are based on the three batteries deeply analysed in this thesis and on others five analysed by Fiamm project team. Nowadays, supplier n.8 appears to be the best one. Fiamm has planned to evaluate other two batteries within the next months so the partial result obtained in this thesis could be different from the final one

On the Discrepancy between Theoretical and X-Ray Concentration-Mass Relations for Galaxy Clusters

[Abridged] In the past 15 years, the concentration-mass relation has been investigated diffusely in theoretical studies. On the other hand, only recently has this relation been derived from X-ray observations. When that happened, the results caused a certain level of concern: the X-ray normalizations and slopes were found significantly dissimilar from those predicted by theory. We analyzed 52 objects, simulated each time with different physical recipes for the baryonic component, as well as 60 synthetic X-ray images, to determine if these discrepancies are real or artificial. In particular, we investigate how the simulated concentration-mass relation depends (1) on the radial range used to derive the concentration, (2) on the presence of baryons in the simulations, and on the prescription used to reproduce the gas. Finally, we evaluate (3) how the results differ when adopting an X-ray approach for the analysis and (4) how the selection functions based on X-ray luminosity can impact the results. All effects studied go in the direction of alleviating the discrepancy between observations and simulations, although with different significance: while the fitting radial range and the baryonic component play only a minor role, the X-ray approach and selection function have profound repercussion on the resulting concentration-mass relation.Comment: 15 pages, 11 figures, 3 tables, ApJ in press. Significant extension of the study of the selection-function influence and more attentive treatment of errors (results unchanged

Pointing to the minimum scatter: the generalized scaling relations for galaxy clusters

We introduce a generalized scaling law, M_tot = 10^K A^a B^b, to look for the minimum scatter in reconstructing the total mass of hydrodynamically simulated X-ray galaxy clusters, given gas mass M_gas, luminosity L and temperature T. We find a locus in the plane of the logarithmic slopes $a$ and $b$ of the scaling relations where the scatter in mass is minimized. This locus corresponds to b_M = -3/2 a_M +3/2 and b_L = -2 a_L +3/2 for A=M_gas and L, respectively, and B=T. Along these axes, all the known scaling relations can be identified (at different levels of scatter), plus a new one defined as M_tot ~ (LT)^(1/2). Simple formula to evaluate the expected evolution with redshift in the self-similar scenario are provided. In this scenario, no evolution of the scaling relations is predicted for the cases (b_M=0, a_M=1) and (b_L=7/2, a_L=-1), respectively. Once the single quantities are normalized to the average values of the sample under considerations, the normalizations K corresponding to the region with minimum scatter are very close to zero. The combination of these relations allows to reduce the number of free parameters of the fitting function that relates X-ray observables to the total mass and includes the self-similar redshift evolution.Comment: 6 pages, 3 figures. MNRAS in pres

Killer animals in films: Reality vs fiction

Among horror, drama, action, and scifi films, the subgenre of killer animals has been exploited since the very beginnings of cinema. A thorough search of horror/drama/action/sci-fi films with killer animals as the main antagonists was performed, and the data was confronted with the number of human deaths per year caused by animals. A review of movies involving killer animals shows that the animals that causes thousands of human deaths each year do not inspire fear or concern in movies and hence, in the public. This may be in part reverted by educating about diseases transmitted by these animals and the real danger that some animals represent.Fil: Rasia, Luciano Luis. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

A New Interpretation of the Mass-Temperature Relation and Mass Calibration of Galaxy Clusters Based on the Fundamental Plane

Observations and numerical simulations have shown that the relation between the mass scaled with the critical density of the universe and the X-ray temperature of galaxy clusters is approximately represented by $M_\Delta \propto T_X^{3/2}$ (e.g. $\Delta=500$). This relation is often interpreted as evidence that clusters are in virial equilibrium. However, the recently discovered fundamental plane (FP) of clusters indicates that the temperature of clusters primarily depends on a combination of the characteristic mass $M_s$ and radius $r_s$ of the Navarro-Frenk-White profile rather than $M_\Delta$. Moreover, the angle of the FP revealed that clusters are not in virial equilibrium because of continuous mass accretion from the surrounding matter. By considering both the FP and the mass dependence of the cluster concentration parameter, we show that this paradox can be solved and the relation $M_\Delta \propto T_X^{3/2}$ actually reflects the central structure of clusters. We also find that the intrinsic scatter in the halo concentration-mass relation can largely account for the spread of clusters on the FP. We also show that X-ray data alone form the FP and the angle and the position are consistent with those of the FP constructed from gravitational lensing data. We demonstrate that a possible shift between the two FPs can be used to calibrate cluster masses obtained via X-ray observations.Comment: Published on ApJ. Matched to published versio

Stativity in the causative alternation? New questions and a new variant

This paper discusses whether capacity to license an internal argument and eventivity are default properties of so-called change-of-state verbs.I draw attention to the claim that, in certain languages, the causative-inchoative alternation extends to a third, external-argument only variant with stative behavior. This variant presents a problem for current generalizations on the Causative Alternation and change-of-state verbs for various reasons, starting from the long-held claim that unique arguments of change-of-state verbs are by default internal. As the causative componentis independently realized in a noneventive, nonepisodic frame, this variant challenges: (a) a widely-agreed rule of event composition, whereby cause, if present, causally implicatesprocess; (b) the claim that CAUSE(R) interpretation of the external argument is a byproduct of transitivization. The discussion: (a) brings out a crosslanguage contrast bearing on default (CAUSE/UNDERGOER) interpretation of unique arguments in equipollent alternations; (b) provides new empirical data supporting the stativity of the (causative) outer v; (c) substantiates important predictions in the literature (e.g. verbs of causation should have stative readings; external-argument-only variants of Object-Experiencer verbs should be found); (d) captures further verb classes allowing the alternation; (e) shows crucial contrasts with other transitive-(in/a)transitive alternations involving null/arb objects.Fil: Mangialavori Rasia, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin

On the coherent rotation of diffuse matter in numerical simulations of galaxy clusters

We present a study on the coherent rotation of the intracluster medium and dark matter components of simulated galaxy clusters extracted from a volume-limited sample of the MUSIC project. The set is re-simulated with three different recipes for the gas physics: $(i)$ non-radiative, $(ii)$ radiative without AGN feedback, and $(iii)$ radiative with AGN feedback. Our analysis is based on the 146 most massive clusters identified as relaxed, 57 per cent of the total sample. We classify these objects as rotating and non-rotating according to the gas spin parameter, a quantity that can be related to cluster observations. We find that 4 per cent of the relaxed sample is rotating according to our criterion. By looking at the radial profiles of their specific angular momentum vector, we find that the solid body model is not a suitable description of rotational motions. The radial profiles of the velocity of the dark matter show a prevalence of the random velocity dispersion. Instead, the intracluster medium profiles are characterized by a comparable contribution from the tangential velocity and the dispersion. In general, the dark matter component dominates the dynamics of the clusters, as suggested by the correlation between its angular momentum and the gas one, and by the lack of relevant differences among the three sets of simulations.Comment: 12 pages, updated to match the MNRAS versio