3,598 research outputs found
Polarisation measurements with a CdTe pixel array detector for Laue hard X-ray focusing telescopes
Polarimetry is an area of high energy astrophysics which is still relatively
unexplored, even though it is recognized that this type of measurement could
drastically increase our knowledge of the physics and geometry of high energy
sources. For this reason, in the context of the design of a Gamma-Ray Imager
based on new hard-X and soft gamma ray focusing optics for the next ESA Cosmic
Vision call for proposals (Cosmic Vision 2015-2025), it is important that this
capability should be implemented in the principal on-board instrumentation. For
the particular case of wide band-pass Laue optics we propose a focal plane
based on a thick pixelated CdTe detector operating with high efficiency between
60-600 keV. The high segmentation of this type of detector (1-2 mm pixel size)
and the good energy resolution (a few keV FWHM at 500 keV) will allow high
sensitivity polarisation measurements (a few % for a 10 mCrab source in 106s)
to be performed. We have evaluated the modulation Q factors and minimum
detectable polarisation through the use of Monte Carlo simulations (based on
the GEANT 4 toolkit) for on and off-axis sources with power law emission
spectra using the point spread function of a Laue lens in a feasible
configuration.Comment: 10 pages, 6 pages. Accepted for publication in Experimental Astronom
PCN52 Positron Emission Tomography/Computed Tomography Imaging for Non-Small Cell Lung Cancer: A Budget Impact Analysis
Impact of thermal blanching and thermosonication treatments on watercress (Nasturtium officinale) quality: process optimisation and microstructure evaluation
Galhas De Insetos Da Serra Geral, Caetité, Bahia, Brasil
We inventoried and characterized the kinds of gall, gall-inducing insects and host plants from Serra Geral between August 2013 and July 2014. Two phytophysiognomies, cerrado sensu stricto and caatinga-cerrado, were examined monthly along transects during ca. 4 hours per visit, totaling 48 hours of sampling effort. A total of 49 gall morphotypes were found on 14 species of host plants in 18 genera and 13 families. Fabaceae and Malpighiaceae were the families with the most galls, with 22 and 10 gall morphotypes, respectively. The genera of host plant with the greatest richness of galls were Copaifera L. (n=10), Bauhinia Benth. (n=6), and Mimosa L. (n=5). Galls were found on leaves, buds and stems. The majority of the galls were globoid, glabrous, isolated, and one-chambered. The inducers belong to Coleoptera, Diptera, and Lepidoptera, Cecidomyiidae (Diptera) being the most frequent and diverse gall-inducers. The associated fauna included parasitoids (Hymenoptera), successors (Formicidae), and predators (Pseudoscorpiones), obtained from 13, 2, and 1 gall morphotypes, respectively. Five plant taxa are recorded as hosts of gall-inducing insects for the first time. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16111
Characteristics of austenitic stainless steel nitrided in a hybrid glow discharge plasma
A nitriding process based on two distinct nitrogen glow discharge modes, with sample temperatures ranging from 380 °Cto480°C, was employed to treat the surface of austenitic stainless steel (SS 304). The temperature is controlled exclusively by switching the operation conditions of the discharges. First mode of operation is the conventional one, named cathodic, which runs at higher pressure values (1 mbar) in comparison to the second mode, named anodic, which runs at the pressure range of 10-3 -10-2 mbar. Cathodic mode is used to quickly heat the sample holder, by the high ion flux. On the other hand, in the anodic mode, due to the lower operation pressure, higher effective ion acceleration takes place, which allows deeper ion implantation into the sample surface. This hybrid process was thoroughly explored regarding the duty cycle and conditions of operation, to achieve optimal performance of the treatments, which led to the attainment of surface hardness for samples of AISI SS 304 as high as 20 GPa and improvements including higher elastic modulus and resistance against corrosion. Detailed comparison among samples treated by this process with others treated by conventional method was done using nanoindentation, Auger Electron Spectroscopy (AES) and corrosion resistance testing
Tipologia socioambiental de cidades médias no Brasil: aportes para um desenvolvimento urbano sustentável
The global urbanization of the territories, which is an important ongoing human ecological phenomenon, and whose environmental impacts have local, regional and global levels, has the remarkable property of a sharp growth of small and intermediate cities, in which capacity of planning and management is usually negligible, when they are compared to large cities. This is what takes place in Brazil, where medium-sized cities, those with populations between 100,000 and 500,000 residents are growing faster than large cities from mid-1990. The article aims to chart a typology of medium Brazilian cities, through multivariate statistical analysis. The resulting typology identifies two types of cities, with different social, environmental and management demands. Some of these cities are located in biodiversity hotspots. In parallel, we have compiled statistics on environmental management in place in these cities. Our results demonstrate low effectiveness of environmental management actions in these municipalitiesA CAPES, y al Ministerio de Agricultura, Alimentación y Medio Ambiente del gobierno español, por la financiación al Proyecto Ecología Urbana en Regiones Metropolitanas de Brasil: Paisaje, Calidad de Vida y Desarrollo Humano [Plan Nacional de I+D+i (CSO2009 12689)
Phenolic profile and antioxidative properties of the beefsteak fungus Fistulina hepatica
The phenolic composition of the edible beefsteak fungus Fistulina hepatica was determined by HPLC/DAD. The results showed a profile composed by caffeic, p-coumaric and ellagic acids, hyperoside and quercetin. Ellagic acid was the main compound in this species. Beefsteak fungus was also investigated for its capacity to act as a scavenger of DPPH radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid). Good results were obtained against DPPH and superoxide radicals and hypochlorous acid but a prooxidant effect was observed for hydroxyl radical
Generating a checking sequence with a minimum number of reset transitions
Given a finite state machine M, a checking sequence is an input sequence that is guaranteed to lead to a failure if the implementation under test is faulty and has no more states than M. There has been much interest in the automated generation of a short checking sequence from a finite state machine. However, such sequences can contain reset transitions whose use can adversely affect both the cost of applying the checking sequence and the effectiveness of the checking sequence. Thus, we sometimes want a checking sequence with a minimum number of reset transitions rather than a shortest checking sequence. This paper describes a new algorithm for generating a checking sequence, based on a distinguishing sequence, that minimises the number of reset transitions used.This work was supported in part by Leverhulme Trust grant number F/00275/D, Testing State Based Systems, Natural Sciences and Engineering Research Council (NSERC) of Canada grant number RGPIN 976, and Engineering and Physical Sciences Research Council grant number GR/R43150, Formal Methods and Testing (FORTEST)
A Novel Approach to Optimize the Design of Parts for Additive Manufacturing
Additive Manufacturing (AM) is a term used to group the different manufacturing processes that use various techniques, each of which is capable of producing parts made from a wide variety of materials, such as polymers, ceramics, metals, wood, among others. All these technologies allow parts manufacturing by adding successive layers of material which can be liquid, powder or wire. In order to take advantages of the geometric freedom offered by AM, Topological Optimization (TO) is usually used. TO provides the optimal distribution of material for a given request. The main objective is weight reduction, without compromising the original resistance of an existing part produced by traditional processes. Taking advantage of the freedom allowed by the AM process and conciliating it with the CAE features, which allow to simulate the parts behavior when subjected to the expected loads, a new approach methodology was drawn in order to shorten the time needed to optimize parts design for AM. A case study was developed in order to validate the methodology established. The combination of AM and TO revealed promising results, attending to the component efficiency achieved.info:eu-repo/semantics/publishedVersio
Improving the Cut Surface Quality by Optimizing Parameters in the Fibre Laser Cutting Process
One of the main problems with laser cutting equipment is related to the wrong setting of cutting parameters. The mismatching of these parameters leads to a loss of cut surface quality, which is hardly re-established. This loss of quality is usually related to a burr problem. Thus, this study is aimed to improve and optimize this process using a fibre laser equipment. Three important laser cutting parameters were studied in order to investigate their importance in the cut surface quality: radiation power, cutting speed and gas pressure. The different values were performed cutting a stainless steel AISI 316L and a cold rolled steel St12. Metallographic and cut surface analysis, burr and roughness measurements were carried out, supported by a Scanning Electron Microscopy and profilometry. Through the Taguchi statistical analysis model, it is possible to indicate the best set of laser cutting parameters. It was verified that the values recommended by the equipment manufacturer can be optimized, being possible to use less radiation power in the laser beam with greater speed of cut, providing a better cut surface quality, improving and optimizing the entire process.info:eu-repo/semantics/publishedVersio
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