188 research outputs found

    PADC-NTM Applied in 7Li+Pb at 31 MeV Reaction Products Study

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    Passive nuclear track methodology (NTM) is applied to study charged particles products of the reaction 7Li+Pb at ~ 31 MeV. It is a contribution to the 8pLP Project (LNL-INFN-Italy) in where we show an alternative approach to register charged particle from reaction fragments by PADC detection. The main advantage is that the passive system integrates data over the whole experiment and has its importance for low rate reaction processes. Reaction products as well as scattered beam particles are determined from track shape analysis. Some limitations are inherent to NTM since a priori knowledge is required to correlate track size distribution given by each type of particle emerging from the target. Results show that the passive technique gives useful information when applied in reaction data interpretation for a relatively large range of particle types

    Filling holes under non-linear constraints

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    Publisher Copyright: © 2023, The Author(s).In this paper we handle the problem of filling the hole in the graphic of a surface by means of a patch that joins the original surface with C1-smoothness and fulfills an additional non-linear geometrical constraint regarding its area or its mean curvature at some points. Furthermore, we develop a technique to estimate the optimum area that the filling patch is expected to have that will allow us to determine optimum filling patches by means of a system of linear and quadratic equations. We present several numerical and graphical examples showing the effectiveness of the proposed method.publishersversionpublishe

    Assessment of Three Varieties of Morus indica L. on the Growth and Performance of a Bivoltine Breed of Bombyx mori L. in Nigeria

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    The effect of three varieties of Mulberry leaves (Morus indica L.: K2, S-36 and EFG) on growth and performance of a bivoltine breed of Silkworm (Bombyx mori L.) was evaluated in a Tropical rainforest belt of South-West Nigeria. At the end of the fifth instar, S-36 variety of Mulberry leaves significantly  increased the larvae mean weight to 1.28g when compared with K2  (1.07grams) and EFG (0.93grams) (P<0.5). Though the three varieties did not show any significant difference (P<0.05) in terms of  weight of wet cocoons ( K2 -1.83g, S-36 -1.95g and EFG -1.80g) , however S-36 significantly  increased the filament length of cocoon spun by Bombyx mori when compared with others ( S-36 produced mean length of  824m, K2, 594m and EFG, 432m).The results revealed that the nutritive value of Mulberry leaves varied from each other. Except for the adult Bombyx mori all other results presented a significantly higher performance of the S-36 variety above K2 and EFG variety (P<0.05). The result showed that S-36 significantly supported the growth and productivity of Bombyx mori than K2 and EFG leaves. Keywords: Mulberry leaves, Bombyx mori, Instar, Cocoon

    Simulation of Dose Estimations from Solar Protons: A PMMA-Bi2O3 Shielding Model for Space Exploration

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    Adverse effects of long-term exposure to galactic cosmic radiation (GCR) pose a non negligible obstacle for future space exploration programs; the high-LET-particle-rich environment has an adverse effect on human health. Concomitant to GCR we have as well solar particle radiation. Long term space exploration will rely on adequate and highly efficient shielding materials that will reduce exposure of both biosystems and electronic equipment to GCR and solar particles. The shield must attenuate efficiently heavy GCR ions, by breaking them up into less-damaging fragments and secondary radiation: biologically damaging energetic neutrons and highly charged and energetic HZE- particles. An approach to this problem is the development of shielding compounds. Shielding materials should address the conditions of different aspects of a given mission, e.g. time duration and travel path. The Monte Carlo method (GEANT4) is here employed to estimate the effects of a shielding material based on the recently developed Bi2O3-based compound (Cao et al., 2020). In the present study GEANT4 code is used to make estimations of attenuation of solar protons. The objective is to provide some insight about the effect of the new composite shield that has an intrinsic capability for dose reduction

    Filling holes under non-linear constraints

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    In this paper we handle the problem of filling the hole in the graphic of a surface by means of a patch that joins the original surface with C1-smoothness and fulfills an additional non-linear geometrical constraint regarding its area or its mean curvature at some points. Furthermore, we develop a technique to estimate the optimum area that the filling patch is expected to have that will allow us to determine optimum filling patches by means of a system of linear and quadratic equations. We present several numerical and graphical examples showing the effectiveness of the proposed method.Funding for open access publishing: Universidad de Granada/CBUANational funds through the FCT - Fundação para a Ciência e a TecnologiaProjects UIDB/00297/2020 and UIDP/00297/2020 (Center for Mathematics and Applications

    ZnS (Mn) Nanoparticles as Luminescent Centers for Siloxane Based Scintillators

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    Synthesis of oleic acid stabilized ZnS nanocrystals activated with Mn is pursued. A hydrothermal method where high pressure and temperature are applied to control the nanocrystals growth is adopted. Capping the nanoparticle surface with oleic acid (OA) improved light output. Samples loaded with both the phosphor and the neutron sensitizer have been produced and tested in a preliminary test as alpha particle detectors and secondly as thermal neutron detectors. The results support further development for siloxane-based scintillator detectors employing ZnS (Mn) nanoparticles

    PADC Detected External Neutron Field by Nuclear Tracks at RFX-mod

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    Measured neutron signals relevant for plasma diagnostics on Reversed Field pinch eXperiment, RFX-mod, are obtained by nuclear track methodology with PADC-NtD’s. this technique provides the external neutron field values around the RFX-mod installation during pulsed operation. Charged particles from (n, p) and (n, α) reactions are related to formed latent tracks. these are etched in a thermoregulated water bath with a 6.25M, KOh solution at 60oC. Observed tracks were analyzed to determine track density from which neutron fluence spatial values should be derived. Results indicate that the neutron density in the surrounding environment change at most 40%. the epithermal component is 60% higher than that corresponding to the thermal region. the estimated neutron fluence for the whole experiment is 7.5×1010 neutrons cm2/s

    CsI(Tl) scintillators as gamma-ray detectors for the identification of hidden explosives

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    We report on the performances of CsI(Tl) crystals as gamma-ray detectors, compared with standard NaI(Tl). Energy resolution from E_gamma = 122 keV up to E_gamma = 7.6 MeV and light output yield of different CsI(Tl) crystals and read-out configurations (photomultiplier tubes, photodiodes and avalanche photodiodes) have been measured.Published234-2387A. Geofisica per il monitoraggio ambientale e geologia medicaJCR Journa

    The state, civil society and social rights in contemporary Russia

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    peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=fjcs21peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=fjcs2

    Application programming interface guided QA plan generation and analysis automation

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    PURPOSE: Linear accelerator quality assurance (QA) in radiation therapy is a time consuming but fundamental part of ensuring the performance characteristics of radiation delivering machines. The goal of this work is to develop an automated and standardized QA plan generation and analysis system in the Oncology Information System (OIS) to streamline the QA process. METHODS: Automating the QA process includes two software components: the AutoQA Builder to generate daily, monthly, quarterly, and miscellaneous periodic linear accelerator QA plans within the Treatment Planning System (TPS) and the AutoQA Analysis to analyze images collected on the Electronic Portal Imaging Device (EPID) allowing for a rapid analysis of the acquired QA images. To verify the results of the automated QA analysis, results were compared to the current standard for QA assessment for the jaw junction, light-radiation coincidence, picket fence, and volumetric modulated arc therapy (VMAT) QA plans across three linacs and over a 6-month period. RESULTS: The AutoQA Builder application has been utilized clinically 322 times to create QA patients, construct phantom images, and deploy common periodic QA tests across multiple institutions, linear accelerators, and physicists. Comparing the AutoQA Analysis results with our current institutional QA standard the mean difference of the ratio of intensity values within the field-matched junction and ball-bearing position detection was 0.012 ± 0.053 (P = 0.159) and is 0.011 ± 0.224 mm (P = 0.355), respectively. Analysis of VMAT QA plans resulted in a maximum percentage difference of 0.3%. CONCLUSION: The automated creation and analysis of quality assurance plans using multiple APIs can be of immediate benefit to linear accelerator quality assurance efficiency and standardization. QA plan creation can be done without following tedious procedures through API assistance, and analysis can be performed inside of the clinical OIS in an automated fashion
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