DArk Matter Particle Explorer (DAMPE), a satel- lite-based cosmic-ray (CR) and gamma-ray measurement experiment, relies on its calorimeter to measure the energy of incident particles. The calorimeter ...adopts crystals of bismuth germanium oxide (BGO) as scintillating material, and it is designed to aim for measurements of energy ranging from 50 GeV to 100 TeV in the case of a CR nucleus. This article concerns the response of the BGO calorimeter to nucleus-type CRs. CRs with very low energy can rarely reach the detector due to the Earth's magnetic field. A cutoff on lower energy can be observed in the energy spectrum. In this article, the cutoff is used to study the response of the calorimeter. Carbon, neon, silicon, and iron are analyzed separately in comparison with Monte Carlo simulations by Geant4.
Poly(ethylene glycol) (PEG) dialdehyde diethyl acetals of different molecular sizes were synthesized and used to generate in situ PEG dialdehydes for the crosslinking of partially reacetylated ...chitosan via Schiff reaction and hydrogenation of the aldimines. The water-soluble products obtained were instrumentally characterized. Upon freeze-drying, they aggregated to yield insoluble soft and spongy biomaterials, that swelled immediately upon contact with water. When exposed to papain and lipase, at physiological pH values, progressive dissolution of the biomaterials was observed, but no dissolution took place with lysozyme, collagenase and amylase. They were found to be biocompatible towards Caco-2 cells. These crosslinked partially acetylated chitosans seem suitable for medical items when prompt resorption is sought.
We analyze the dependence of the Secondary Electron Emission yield on the beam incidence angle (θ) in the case of Faraday cups used for diagnosis of laser-plasma. We show that this dependence follows ...a secα(θ) law, consequently θ ≠ 0 situations (i.e. non-normal incidence) should be treated with care to avoid wrong measurements.
A renewed interest on Vertical Axis Wind Turbines (VAWTs) arose from their great capacity for integration within urban areas and for applications of distributed generation. In order to be able to ...highly improve their performance, making them competitive with respect to the more consolidated Horizontal Axis Wind Turbines (HAWTs), it is fundamental to have a deeper comprehension of their fluid dynamic behavior. In order to reach this goal, a two-bucket Savonius rotor has been designed, built from a PVC pipe with a nominal diameter of 200mm, and tested in the wind tunnel of the Department of Mechanics, Mathematics and Managment (DMMM) of the Politecnico di Bari. The Savonius rotor is connected to an AC brushless servo motor, able to control either the braking torque or the rotational speed. This paper describes the experimental evaluation of the unsteady flow field downstream the rotor by means of a Constant Temperature hot wire Anemometer (CTA). Whilst, for performance analysis, the torque measurements have been obtained directly from the Servo Amplifier torque monitor.
Bone morphogenetic protein (BMP), associated with N,N-dicarboxymethyl chitosan, is used to induce or facilitate the repair of articular cartilage lesions. This association is intended for the ...synergistic potentiation of the respective biological effects. Data show that BMP-7 enhances the in vivo proliferation of cells with chondrocytes phenotype in the articular environment, leading to partial healing of the articular surface of the lesions. N,N-dicarboxymethyl chitosan is found to be useful as a molecular carrier or drug delivery agent.
The osteointegration of Hydroxyapatite (HA), Titanium (Ti-6Al-4V: Ti), Zirconia (ZrO2), Alumina (Al2O3) and 2 biological glasses (AP40 and RKKP) was comparatively investigated in normal and ...osteopenic rats by means of histomorphometry. Thirty-six Sprague Dawley female rats were left intact (Group C) while 36 were ovariectomized (Group OVX). Group C and OVX were further divided into 6 subgroups. After 16 weeks all animals were submitted to the femoral implant of nails made of the above-mentioned materials. Eight weeks after implantation the animals were euthanized, the femurs were harvested for histomorphometric analysis. The data showed that: (1) all the tested materials were biocompatible in vitro; (2) no significant differences existed in Affinity Index (AI) of Group C; and (3) results from paired comparison applied to the AI showed significant differences among the Groups C and OVX. The AI did not significantly change among intact groups, while it significantly decreased when some materials were implanted in OVX subgroups (AP40, ZrO2 and Ti-6Al-4V: p < 0.0005, p < 0.05 and p < 0.01). It is confirmed that bone mineral density is a strong predictor of the osteointegration of an orthopedic implant and that the use of pathological animal models is necessary to completely characterize biomaterials.
The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei ...components between 10 GeV and 100 TeV. The silicon–tungsten tracker–converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron–positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m2. Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements.
In-flight performance of the DAMPE silicon tracker Tykhonov, A.; Ambrosi, G.; Asfandiyarov, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2019, Letnik:
924
Journal Article
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DAMPE (DArk Matter Particle Explorer) is a spaceborne high-energy cosmic ray and gamma-ray detector, successfully launched in December 2015. It is designed to probe astroparticle physics in the broad ...energy range from few GeV to 100 TeV. The scientific goals of DAMPE include the identification of possible signatures of Dark Matter annihilation or decay, the study of the origin and propagation mechanisms of cosmic-ray particles, and gamma-ray astronomy. DAMPE consists of four sub-detectors: a plastic scintillator strip detector, a Silicon–Tungsten tracKer–converter (STK), a BGO calorimeter and a neutron detector. The STK is composed of six double layers of single-sided silicon micro-strip detectors interleaved with three layers of tungsten for photon conversions into electron–positron pairs. The STK is a crucial component of DAMPE, allowing to determine the direction of incoming photons, to reconstruct tracks of cosmic rays and to estimate their absolute charge (Z). We present the in-flight performance of the STK based on two years of in-flight DAMPE data, which includes the noise behavior, signal response, thermal and mechanical stability, alignment and position resolution.
Preliminary results on the modifications induced by the growth of a Chinese Hamster Ovary (CHO) cell line on the surface of a CORD 1014 ceramic cordierite are reported. Results proved that cells ...strongly modify the crystallography and the chemical composition of the surface and near surface regions of the cordierite.
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