Cu-catalyzed Si-NWS grown on “carbon paper” as anodes for Li-ion cells

The very high theoretical capacity of the silicon (4200mAh/g more than 10 times larger than graphite), environmental-friendly, abundant and low-cost, makes it a potential candidate to replace graphite in high energy density Li-ion batteries. As a drawback, silicon suffers from huge volume changes (300%) on alloying and dealloying with Li, leading a structural deformation that induces disruption. The use of nanostructured silicon materials has been shown to be an effective way to avoid this mechanical degradation of the active material. In this paper the synthesis of silicon nanowires, grown on a highly porous 3D-like carbon paper substrate by CVD using Cu as the catalyst, is presented. The use of carbon paper allows to achieve remarkable loadings of active material (2-5 mg/cm2) and, consequently, high capacity densities. The silicon electrode was investigated both morphologically and electrochemically. To improve the electrochemical performance various strategies have been carried out. It was observed that a very slow first cycle (C/40), which helps the formation of a stable solid electrolyte interphase on the silicon surface, improves the performance of the cells; nevertheless, their cycle life has been found not fully satisfactory. Morphological analysis of the Si-NWs electrodes before and after cycling showed the presence of a dense silicon layer below the nanowires which could reduce the electrical contact between the active material and the substrate

An Evaluation Schema for the Ethical Use of Autonomous Robotic Systems in Security Applications

We propose a multi-step evaluation schema designed to help procurement agencies and others to examine the ethical dimensions of autonomous systems to be applied in the security sector, including autonomous weapons systems

Evaluation of time difference of arrival (Tdoa) networks performance for launcher vehicles and spacecraft tracking

Time Difference of Arrival (TDOA) networks could support spacecraft orbit determination or near-space (launcher and suborbital) vehicle tracking for an increased number of satellite launches and space missions in the near future. The evaluation of the geometry of TDOA networks could involve the dilution of precision (DOP), but this parameter is related to a single position of the target, while the positioning accuracy of the network with targets in the whole celestial vault should be evaluated. The paper presents the derivation of the MDOP (minimum dilution of precision), a parameter that can be used for evaluating the performance of TDOA networks for spacecraft tracking and orbit determination. The MDOP trend with respect to distance, number of stations and target altitude is reported in the paper, as well as examples of applications for network performance evaluation or time precision requirement definitions. The results show how an increase in the baseline enables the inclusion of more impactive improvements on the MDOP and the mean error than an increase in the number of stations. The target altitude is demonstrated as noninfluential for the MDOP trend, making the networks uniformly applicable to lower altitude (launchers and suborbital vehicles) and higher altitude (Low and Medium Earth Orbits satellites) spacecraft

Noise control in hospitals: Considerations on regulations, design and real situations

Hospitals include a variety of different spaces with different requirements and levels of sensitivity but also different activities and equipment that can cause high noise levels. Despite the regulations that usually apply to hospitals, noise control is not an easy task. In Italy, the design and construction of hospital buildings must guarantee the acoustic requirements given by the National Regulation (1995-1997), which refers to all new buildings, and by the new Decree on Minimum Environmental Criteria (2017), which applies to public buildings and refers to the Italian acoustic classification scheme (UNI 11367-2010). However, the need to create spaces suitable for the various types of use entails difficulties in identifying where and how to apply the limits set by the legislation. In addition, there are situations in which, regardless of the legislation, it would be opportune to consider more adequate acoustic comfort. In the paper, we analyse the various situations and evaluate the applicability of the legislation. From experimental measurements performed in real cases, some methodological proposals are reported both to ensure the satisfaction of the requirements imposed by the legislation and to meet the needs for more specific acoustic regulations for hospital

Apoptotic signaling through CD95 (Fas/Apo-1) activates an acidic sphingomyelinase.

Intracellular pathways leading from membrane receptor engagement to apoptotic cell death are still poorly characterized. We investigated the intracellular signaling generated after cross-linking of CD95 (Fas/Apo-1 antigen), a broadly expressed cell surface receptor whose engagement results in triggering of cellular apoptotic programs. DX2, a new functional anti-CD95 monoclonal antibody was produced by immunizing mice with human CD95-transfected L cells. Crosslinking of CD95 with DX2 resulted in the activation of a sphingomyelinase (SMase) in promyelocytic U937 cells, as well as in other human tumor cell lines and in CD95-transfected murine cells, as demonstrated by induction of in vivo sphingomyelin (SM) hydrolysis and generation of ceramide. Direct in vitro measurement of enzymatic activity within CD95-stimulated U937 cell extracts, using labeled SM vesicles as substrates, showed strong SMase activity, which required pH 5.0 for optimal substrate hydrolysis. Finally, all CD95-sensitive cell lines tested could be induced to undergo apoptosis after exposure to cell-permeant C2-ceramide. These data indicate that CD95 cross-linking induces SM breakdown and ceramide production through an acidic SMase, thus providing the first information regarding early signal generation from CD95, and may be relevant in defining the biochemical nature of intracellular messengers leading to apoptotic cell death

On the use of the transfer matrix method to evaluate sound insulation in complex building partitions

The transfer matrix method (TMM) represents a powerful tool to investigate wave propagation through different media, which could be particularly suitable to compute sound transmission through building partitions. Even though layered structures can be easily modelled by using the TMM approach, it is not always easy to determine the elastic properties of each layer the partitions is made of. Traditional partitions, generally made in masonry with clay or concrete bricks coupled together with mortar joints, are inhomogeneous and anisotropic structures whose elastic properties are difficult to measure. Again, cross-laminated timber (CLT) panels, due to their peculiar substructure, might exhibit a highly orthotropic behaviour. A homogenisation approach, based on a minimization algorithm of the transmission loss (TL) of the bare structure, is proposed in this paper. It allows to consider inhomogeneous or anisotropic materials as an equivalent elastic solid described by effective frequency-depended elastic properties. The reliability of this approach is validated by comparing the TL of different building partitions computed using the TMM with the experimental sound insulation determined by means of laboratory measurements

Modelling the NO emissions from wildfires at the source level

There is a growing interest to characterize fire plumes in order to control air quality during wildfire episodes and to estimate the carbon and ozone balance of fire emissions. A numerical approach has been used to study the mechanisms of NO formation at the source level in wildfires given that NO plays an important role in the formation of ground-level ozone. The major reaction mechanisms involved in NO chemistry have been identified using reaction path analysis. Accordingly, a two-step global kinetic scheme in the gas phase has been proposed herein to account for the volatile fuel-bound nitrogen (fuel-N) conversion to NO, considering that the volatile fraction of fuel-N is released as NH₃. Data from simulations using the perfectly stirred reactor (PSR) code from CHEMKIN-II package with a detailed kinetic mechanism (GDF-Kin^® 3.0) have been used to calibrate and evaluate the global model under typical wildfire conditions in terms of the composition of the degradation gases of vegetation, the equivalence ratio, the range of temperatures and the residence time

Analysis of Direct and Flanking Sound Transmission Between Rooms with Curtain Wall Facades

Curtain walls have nowadays reached good performance in terms of façade sound insulation, thermal insulation and solar protection. In this work, flanking and direct structural transmission are analysed with reference to the joints of the mullion of the curtain wall with lightweight plasterboard partitions. Airborne sound insulation and vibrational measurements were made in two adjacent rooms affected by the acoustic problems determined by the curtain wall joint. Traditional acoustic measurements carried out according to EN ISO 16283-1 highlight problems in sound insulation between rooms, but without any indication on different sound transmission paths through the wall. Vibrational measurements were made for every part of the system (frame columns and beams, windows’ glasses, plasterboard wall, plasterboard false ceiling, etc.) to better understand the sound transmission paths in these kinds of structures. Taking into account previous works and measurements made in this research field, different solutions for curtain wall structures are analysed and technical suggestions are given to improve airborne sound insulation between rooms separated by partitions mounted up to metal frames

Evaluating homophily in networks via HONTO (HOmophily Network TOol): a case study of chromosomal interactions in human PPI networks

It has been observed in different kinds of networks, such as social or biological ones, a typical behavior inspired by the general principle 'similarity breeds connections'. These networks are defined as homophilic as nodes belonging to the same class preferentially interact with each other. In this work, we present HONTO (HOmophily Network TOol), a user-friendly open-source Python3 package designed to evaluate and analyze homophily in complex networks. The tool takes in input from the network along with a partition of its nodes into classes and yields a matrix whose entries are the homophily/heterophily z-score values. To complement the analysis, the tool also provides z-score values of nodes that do not interact with any other node of the same class. Homophily/heterophily z-scores values are presented as a heatmap allowing a visual at-a-glance interpretation of results. AVAILABILITY AND IMPLEMENTATION: Tool's source code is available at https://github.com/cumbof/honto under the MIT license, installable as a package from PyPI (pip install honto) and conda-forge (conda install -c conda-forge honto), and has a wrapper for the Galaxy platform available on the official Galaxy ToolShed (Blankenberg et al., 2014) at https://toolshed.g2.bx.psu.edu/view/fabio/honto