Shield Elements Research Articles

Measurement of the background in the CMS muon detector in pp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${p}{p}$$\\end{document}-collisions at s=13\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{s} = 13$$\\end{document} TeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\,\ ext {Te}\\hspace{-.08em}\ ext {V}$$\\end{document}

The CMS detector, including its muon system, has been operating at the CERN LHC in increasingly challenging conditions for about 15 years. The muon detector was designed to provide excellent triggering and track reconstruction for muons produced in proton–proton collisons at an instantaneous luminosity (L\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {L}$$\\end{document}) of 1×1034\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1 \ imes 10^{34}$$\\end{document} cm-2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-2}$$\\end{document}s-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document}. During the Run 2 data-taking period (2015–2018), the LHC achieved an instantaneous luminosity of twice its design value, resulting in larger background rates and making the efficient detection of muons more difficult. While some backgrounds result from natural radioactivity, cosmic rays, and interactions of the circulating protons with residual gas in the beam pipe, the dominant source of background hits in the muon system arises from proton–proton interactions themselves. Charged hadrons leaving the calorimeters produce energy deposits in the muon chambers. In addition, high-energy particles interacting in the hadron calorimeter and forward shielding elements generate thermal neutrons, which leak out of the calorimeter and shielding structures, filling the CMS cavern. We describe the method used to measure the background rates in the various muon subsystems. These rates, in conjunction with simulations, can be used to estimate the expected backgrounds in the High-Luminosity LHC. This machine will run for at least 10 years starting in 2029 reaching an instantaneous luminosity of L=5×1034cm-2s-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {L} = 5 \ imes \ ext {10}^\ ext {34}\\,\ ext {cm}^\ ext {-2}\\,\ ext {s}^\ ext {-1}$$\\end{document} and increasing ultimately to L=7.5×1034cm-2s-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {L} = 7.5 \ imes \ ext {10}^\ ext {34}\\,\ ext {cm}^\ ext {-2}\\,\ ext {s}^\ ext {-1}$$\\end{document}. These background estimates have been a key ingredient for the planning and design of the muon detector upgrade.

Autonomous construction of lunar infrastructure with in-situ boulders

Significant infrastructure is required to establish a long-term presence of humans on the lunar surface. In-situ resource utilization (ISRU) is a fundamental approach to ensure the viability of such construction. Here, we investigate the feasibility of constructing blast shields as one example of lunar infrastructure using unprocessed lunar boulders and an autonomous robotic excavator. First, we estimate the volume of unprocessed material required for the construction of blast shield segments. Secondly, we quantify the amount of available boulders in two exploration zones (located at the Shackleton-Henson Connecting Ridge and the Aristarchus Plateau pyroclastic deposit) using LRO NAC images and boulder size-frequency distribution laws. In addition, we showcase an alternative approach that relies on Diviner rock abundance data. Thirdly, we use a path planning algorithm to derive the distance, energy, and time required to collect local material and construct blast shield elements. Our results show that our construction method requires two orders of magnitudes less energy than alternative ISRU construction methods, while maintaining realistic mission time and payload capacity margins.

Evolutionary change of crystallographic orientation and coccolith morphology: Neogene-Quaternary Umbilicosphaera (Prymnesiophyceae) lineage

The crystallographic orientation and its relationship to the morphology of coccoliths were investigated for the Neogene-Quaternary calcareous nannoplankton Umbilicosphaera lineage using scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The c-axis of the calcite forming the distal shield elements was inclined upward at 66–68° (U. sibogae), 65–68° (U. foliosa), 57–58° (U. rotula), and 55–57° (U. patera) from the coccolith plane. Accordingly, the outward dip angle of one of the {101¯4} faces forming the surface of the distal shield of U. patera coccolith was shallower than those of U. sibogae and U. foliosa, explaining the nearly flat distal shield and the steep inner slope, formed by another equivalent {101¯4} face, around the central opening of U. patera. Our results showed that the evolution from U. rotula to U. patera during the Late Miocene was not accompanied by a change in crystallographic orientation. In contrast, the evolution from U. patera to U. sibogae and U. foliosa during the Pliocene was accompanied by a rotation of the orientation. The crystallographic orientation of calcite nuclei on the baseplate with a combination of other factors would have resulted in species-specific differences in shield shape and suture lines within the same phylogeny, consequently producing morphological diversity in the coccolith throughout geological time.

Fabrikasi dan Karakterisasi Bioplastik Timbal Sebagai Bahan Alternatif Proteksi Radiasi Sinar-X

X-ray radiation is widely used in the medical field for early detection of a health disorder. Radiation can pose a danger to its users, one of which is genetic mutation. The use of radiation shields can minimize the adverse effects of radiation. Lead (Pb) is widely used as a constituent of radiation shields. Bioplastics are attractive substitutes for petrochemical plastics due to their biodegradability, renewables, and resource abundance. Cassava and corn starch can be used to make bioplastics. In this study, researchers fabricated radiation protection materials made from biodegradable plastic or bioplastic with varying concentrations of lead acetate doping as a radiation shielding element. A mixture of cassava starch and lead acetate as a radiation protection agent can be suggested as an alternative. Based on research conducted with variations in composition between cassava starch and lead acetate 45:55 data on the effectiveness of the resulting radiation absorption of 49.4%. Based on the shape of the surface topography of the SEM image, which results in a relatively balanced mixture of content, the grouping of lead content is relatively even. However, based on the results of the EDX, there is an anomaly in the amount of weight content of cassava starch; this is suspected because the authors used cassava starch without the addition of synthetic ingredients, so the resistance to the temperature needs to be reviewed. Keywords: bioplastics, cassava starch, lead acetate, radiation shield, SEM, EDX

Gamma radiation shielding simulation for thermoplastic elastomer and silicon rubber/alloy dopant with functional nanoparticle

With the global energy crisis worsening, the research and application of new energy have become a strategic objective for the major countries’ long-term development in the twenty-first century. Nuclear energy technology development and application have become central to new energy development. Numerous types of high-energy radiation (such as X-rays, gamma rays, and neutron rays) produced by nuclear materials not only impose stricter requirements on the radiation-resistant materials used in the reactor but also risk causing significant environmental pollution (nuclear pollution) and serious harm to human life and health if a leak does not form. As a result, the prudent control and protection of nuclear radiation have become critical issues in the development of nuclear energy. With the rapid development of nuclear power today, it is necessary to seek new nuclear radiation protection materials, particularly those with high energy, penetrating ability, and other neutron-protective material characteristics. This is a new type of nuclear power design and construction of critical materials. In this study, WinXCom software is used to simulate the shielding properties of the used functional shielding element, compounds of metal oxide, and the mixture of RTV and TPE with the functional nanoparticle and observe the K-edge absorption of the material used. Based on the simulation, the shielding performance of the selected element of Sm was observed to have the smallest weak gap absorption zone of 40-47 MeV in common medical radiation of 30-150 KeV. Different sets of combinations of shielding material were simulated and found that the combination of WO3 with Sm2O3 gave the most pronounced radiation shielding performance with two strong absorption peaks at 46.8 KeV and 69.5 KeV. RTV composite (Sm2O3+RTV+ WO3) with WO3 as matrix gave the best shielding performance and was used as a reference for the manufacture of the new type of shielding materials.

Mechanical, thermal, and electrical properties of amine‐ and non‐functionalized reduced graphene oxide/epoxy carbon fiber‐reinforced polymers

AbstractGraphene and its related materials are increasingly applied in fiber‐reinforced polymers to tailor their material properties for high performance composites. Yet, the use of graphene derivatives that underwent a plasma functionalization process is not well understood. This study uses 1.50 wt.% of unfunctionalized (rGO) or plasma‐treated reduced graphene oxide with amine‐functionalities (frGO) in an epoxy matrix to prepare unidirectional pre‐impregnated carbon fibers. The material characteristics of the graphene‐modified carbon fiber‐reinforced polymers (g‐CFRP) are compared to the neat carbon fiber‐reinforced polymer (CFRP). Both g‐CFRP configurations exhibit a higher void content than the neat CFRP. No significant difference between the CFRP and the g‐CFRPs is observed with respect to the Young's modulus, glass transition temperature, storage modulus, specific heat capacity, thermal conductivity at room temperature, and in‐plane electrical conductivity. Yet, a reduction in ultimate tensile strength of up to −13% is noted. In addition, the apparent interlaminar shear strength and transverse electrical conductivity are increased by up to +12% for the rGO‐CFRP and +52% for the frGO‐CFRP. This knowledge will support the selection of additives for fiber‐reinforced polymers for, for example, lightning strike protection in aircrafts, sensory materials, electromagnetic interference shielding or heat transfer elements.

3D printing of ultralight MWCNT@OCNF porous scaffolds for high-efficiency electromagnetic interference shielding

Towards the difficulties of traditional processing technology in loading high-concentration functional fillers to realize the target electromagnetic interference shielding (EMI SE) performance, and constructing the arbitrary-designated architectures for serving advanced electronics, this work innovatively formulated a functional multi-walled carbon nanotubes@cellulose nanofibers (MWCNT@OCNF) ink for direct ink writing (DIW) 3D printing, which not only possessed high freedom on the proportion of functional particles, but also imparted to the ideal rheological performance for 3D printing. Based on the pre-programmed printing trajectories, a series of porous scaffolds featuring exceptional functionalities were architected. Particularly for the electromagnetic waves (EMWs) shielding behaviors, the optimized one with “full-mismatched” architecture posed the ultralight structure (0.11 g/cm3) and superior SE performance (43.5 dB) in the X-band frequency region. More encouragingly, the 3D-printed scaffold with hierarchical pores possessed the ideal electromagnetic compatibility on EMWs signal, where the radiation intensity generated by EMWs signal fluctuated in a step pattern in 0 and 1500 μT/cm2 as loading and unloading scaffolds. Overall, this study paved a novel path for the formulation of functional inks to print lightweight, multi-structure, and high-efficiency EMI SE scaffolds for the next-generation shielding elements.

METHODS FOR MITIGATION OF MAGNETIC FIELD GENERATED BY UNDERGROUND POWER CABLES IN POLYETHYLENE PIPES MADE OF COMPOSITE MAGNETIC MATERIAL

The magnetic field of a high-voltage (330 kV) underground single-circuit power cable line, laid in a polyethylene pipe having magnetic properties, with the use of special loose-fill/fill-up soil of different dimensions (bulk) is studied by computer modeling. The pipe and additional soil around and near the cables are made of a composite material with effective magnetic properties and can act as a magnetic shield that reduces the level of the field on the ground. The efficiency of field shielding depending on the height and width of the composite loose-fill/fill-up soil is analyzed. The existence of the optimal not large (in height) fill-up soil for the best mitigation of the magnetic field on the ground directly above the cables, and the influence of the width of the loose-fill/fill-up soils on the shielding efficiency are revealed. The characteristic features of the magnetic field distribution within the considered shielding elements of the cable line depending on the availability or non-availability of composite loose-fill soil and the height of the fill-up soil with effective magnetic properties are presented. The shielding efficiency of underground single-circuit three-phase power cable lines when using the magnetic fill-up soil with a certain small height (volume) is grounded. References 11, figures 4.

Multifunctional Nanocellulose/Carbon Nanotube Composite Aerogels for High-Efficiency Electromagnetic Interference Shielding

Bio-based specialized components have emerged as a promising trend to limit the use of petroleum derivatives. Conversely, the current use of electronic systems has conditioned the emission of electromagnetic waves that interfere with high-precision devices and harm human health. Thus, robust, ultralight, and conductive nanocellulose-based aerogels paired with carbon nanotubes appear as an electromagnetic interference (EMI) shielding biomaterial to reduce the dispersion of microwaves emitted or received from a device. This study proposes a reliable aerogel system to deflect radiation by integrating TEMPO-oxidized cellulose nanofibrils, cationic cellulose nanocrystals, and sodium alginate, with carbon nanotubes at various concentrations. After inducing gelation, the aerogels were obtained by freeze drying. According to zeta potential and FTIR analysis data of nanocellulose, the aerogel frame was induced by electrostatic attraction and hydrogen bonds between the cellulosic matrix and the nanofillers. Finally, lightweight (density < 0.075 g/cm3), highly porous (porosity > 95.47%), conductive (up to 26.2 S/m), mechanically resistant, and EMI-protective aerogels were obtained, proving their potential to be used as green and lightweight shielding elements against electromagnetic radiation.

Ultrathin MXene/Polymer Coatings with an Alternating Structure on Fabrics for Enhanced Electromagnetic Interference Shielding and Fire-Resistant Protective Performances

Wearable electromagnetic interference (EMI) shielding fabrics are highly desirable with the rapid development of electronic devices and wireless communications where electromagnetic pollution is a great concern for human health and the reliability of precision equipment. The balance between EMI shielding efficiency (SE) and the flexibility of fabric is still challenging because of the generally opposite requirements for coating thickness. In this work, MXene/insulative polymer coating with an alternating structure is fabricated via a stepwise assembly technique to judiciously combine excellent shielding elements, a reasonable structure, and high nanofiller content together in the coating. Owing to this novel strategy, the coating with nanoscale thickness (∼500 nm) has realized the commercial requirement for EMI SE and well retained the flexibility and air permeability of the fabric. Compared with the corresponding pure MXene coating, such multilayered coating demonstrates 138.95% enhancement of EMI SE due to the improved dielectrical properties and intensive multiple reflections of electromagnetic waves. Additionally, this hybrid coating also acts as an excellent fire-resistant barrier for the inner flammable fabric to protect human beings and electronic devices in case of accidental fire. This work provides new insights into the rational design of shields with nanometer thickness to realize high EMI shielding performance and good fire resistance for new-generation portable and wearable EMI shielding products.

Design Features of Antenna Arrays of Automotive Radars Based on Transmitting and Receiving Multi-Element Modules

Introduction. Modern vehicles are equipped with radars, which serve as the main sensors of driver assistance systems detecting objects in all weather conditions. Antenna arrays (AA) are the most common type of radar antennas. The coefficient of mutual coupling between adjacent antenna channels has a significant effect on the formed radiation pattern (RP) of an AA. This aspect is important for achieving the required values of gain and side-lobe level (SLL). This article analyses the effect of the proposed design solutions on the main parameters of an automotive radar AA, in particular, on the mutual coupling coefficient between the channels and the SLL of the DP.Aim. To develop an optimal approach to constructing an AA topology in terms of reducing the level of mutual influence of adjacent array channels and obtaining a DP with specified characteristics.Materials and methods. To achieve the required parameters of the designed AA topology, the coplanar and microstrip lines were calculated using the finite element method and shield models.Results. An electrodynamic modeling of a millimetre-wave AA was carried out. The effect of coplanar transmission lines on the RP was shown. The features of applying shielding elements in the AA structure were investigated. Antenna patterns were obtained for both an AA designed based on coplanar transmission lines and that based on the use of shields. The conducted comparative analysis determined the parameters of the substrate optimal for achieving a better level of decoupling between adjacent antenna channels. The values of AA RP obtained during modeling were presented.Conclusion. The use of coplanar transmission lines can significantly reduce the SLL of the DP in the elevation plane. When implementing the module structure of an array (using of sub-arrays), the power dividers are realized. In this case, instead of coplanar lines, it is advisable to use specific microstrip constructions covered with shielding surfaces. In this case, the formation of a given amplitude-phase distribution over aperture is possible. A comparative analysis of the AA topologies with different substrates was carried out with the purpose of achieving improved decoupling. The obtained values of the coefficient of mutual influence of adjacent array channels correspond to those of modern AA of automotive radars. The methods of reducing the parasitic radiation of transmission lines were considered. The AA RP obtained via electrodynamic modeling were presented. The use of a thin substrate with a higher dielectric constant makes it possible to improve the AA characteristics.

Patternable cellulose/MWCNT laminated nanocomposites with anisotropic thermal and electrical conductivity

To construct eco-friendly materials with anisotropic thermal/electrical conductivity and designable structure and shape not only is the goal of electrical materials, but also meets the requirement of sustainable society. In this work, patternable and laminated cellulose/MWCNT nanocomposites with excellent anisotropic thermal and electrical conductivity are prepared by a scalable and eco-friendly process, including a paper-making step, assembly step and in-situ welding step. In the obtained nanocomposites, the cellulose layer acts as the insulator, and the cellulose/MWCNT layer as the electrical and thermal conductor with a special segregated MWCNT network. As a result, the in-plane and through-plane electrical conductivity of the cellulose/MWCNT nanocomposite with 22.7 wt% MWCNT are 1458 and 1.48 × 10-10 S/m, respectively, and the in-plane and through-plane thermal conductivity are 1.98 and 0.34 W·m-1·K-1, respectively. Moreover, the cellulose/MWCNT nanocomposites have high electromagnetic shielding effectiveness of 31.1 dB when the thickness is 0.9 mm, good tensile strength of 156 MPa, and high shape stability at 240 °C. More interestingly, the laminated cellulose/MWCNT materials with patterned shape and sophisticated conductive circuit can be easily fabricated to work as a special and custom-tailor electronic element, thermal management device and electric-heating anti-counterfeiting pattern. Such novel cellulose/MWCNT nanocomposites prepared by a simple, effective and scalable process exhibit a huge potential in environmentally-friendly electrical and thermal management device, electromagnetic shielding element and advanced electronic anti-counterfeiting tag.

Mechanochemical Activation and Spark Plasma Sintering of the Lead-Free Ba(Fe1/2Nb1/2)O3 Ceramics.

This paper investigates the impact of the technological process (Mechanochemical Activation (MA) of the powder in combination with the Spark Plasma Sintering (SPS) method) on the final properties of lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic materials. The BFN powders were obtained for different MA duration times (x from 10 to 100 h). The mechanically activated BFN powders were used in the technological process of the BFN ceramics by the SPS method. The measurements of the BFNxMA ceramic samples included the following analysis: Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), DC electrical conductivity, and dielectric properties. X-ray diffractions (XRD) tests showed the appearance of the perovskite phase of BFN powders after 10 h of milling time. The longer milling time (up 20 h) causes the amount of the perovskite phase to gradually increase, and the diffraction peaks are more clearly visible. Short high energy milling times favor a large heterogeneity of the grain shape and size. Increasing the MA milling time to 40 h significantly improves the microstructure of BFN ceramics sintered in the SPS technology. The microstructure becomes fine-grained with clearly visible grain boundaries and higher grain size uniformity. Temperature measurements of the BFN ceramics show a number of interesting dielectric properties, i.e., high values of electric permittivity, relaxation properties with a diffusion phase transition, as well as negative values of dielectric properties occurring at high temperatures. The high electric permittivity values predestines the BFNxMA materials for energy storage applications e.g., high energy density batteries, while the negative values of dielectric properties can be used for shield elements against the electromagnetic radiation.

Historia, stan i potrzeby badań nad uzbrojeniem z ziem polskich okresów rzymskiego i wędrówek ludów. Spojrzenie subiektywne (pomimo dobrych chęci)

Historia, stan i potrzeby badań nad uzbrojeniem z ziem polskich okresów rzymskiego i wędrówek ludów. Spojrzenie subiektywne (pomimo dobrych chęci)

Steric Shielding of cRGD-Functionalized Nanoparticles from Premature Exposition to Off-Target Endothelial Cells under a Physiological Flow

One of the central impediments for the clinical translation of targeted nanomaterials is their extensive off-target deposition, which can be mainly attributed to the addressed cellular surface structures being ubiquitously present in various other regions, such as the vascular system. This is especially important for the integrin receptor family, which is frequently addressed with ligands such as cRGD (cyclic Arg-Gly-Asp-d-Phe-Lys). Aside from their upregulation during tumor progression, integrins also play a prominent physiological role in endothelial cells, to which particles are exposed immediately after injection. However, there is a lack of understanding of how to modulate the usually undesirable interaction of nanoparticles (NPs) with these cells, especially under physiological conditions, that include the imminent impact of blood flow dynamics on NP behavior. Therefore, in this study, we introduced a steric shielding concept that is based on the addition of longer poly(ethylene glycol) chains into the NP corona, thereby individually camouflaging the ligand activity of cRGD-functionalized polymer NPs. More so, we implemented a method of endothelial cell culture and particle incubation under a constant flow, mimicking physiological conditions (shear stress = 2–14 dyn cm–2). By controlling the surface density (25–75%) and length (3.5 vs 5 kDa) of respective shielding elements, in vitro NP uptake into model endothelial cells could be precisely steered. Additionally, the NP–cell interplay showed significant differences when examined under dynamic conditions, confirming the need for such investigations to improve the clinical translation of nanomaterials.

In Loop Design of the Coils and the Electromagnetic Shielding Elements for the Wireless Charging Systems

This paper deals with in loop design of coupling elements of the wireless charging systems (WChS). The in-loop design is created as a script/User Interface (UI) in MATLAB environment, which is based on finite element models of WChS. Main aim of developed tool is to easily identify the optimal geometrical parameters of the coupling coils. The optimization of the coil’s geometrical and electrical parameters is specified by an algorithm, which is based on definition for transfer of required amount of power and on geometrical restrictions of the target application. The second part of the proposed script/UI is used for user guided design of the electromagnetic shielding. It enables to optimize the shielding parameters in order to reach the limits defined by international standards for safety levels with respect to human exposure. Proposed design methodology together with user interface have been verified though experimental validation. For this purpose, construction of WChS was realized based on the results from in loop design process. Comparisons have been made according to the evaluation of simulation model´s accuracy, that is, the values of self-inductances, mutual inductances, coupling coefficient and gain characteristics have been evaluated (simulations vs. experiments). At the end of the paper the evaluation of the shielding performance was realized, while once more the comparison between simulation and experiments have been made. Received results are showing less than 2% of the relative error. Using presented methodology, the fast optimization actions can be done during design and modelling of WChS.

METHODS OF THE GAUGES BASED ON THE MAGNETOSENSITIVE TRANSISTOR STRUCTURE CHARACTERITIC STABILIZATION

The paper presents the results of a study of methods for stabilizing the characteristics of gauges based on magnetosensitive transistor structures under the influence of temperature. The problem is not only that the temperature directly affects the material, what show up, in particular, in the nature of the charge carrier transfer, but also that the heat dissipation from the semiconductor material in the device when using thermostatic or shielding elements is not always effective, complicates the construction as a whole and leads to an increase in the product mass and dimensions. Temperature dependences of MTS electrophysical characteristics were perfectly investigated and resulted, in particular, in [1]. In this paper, the task was to solve the problem of the two-collector magnetosensitive transistor (DMT) structure parameter thermal stabilization by circuit method.

Design of a compact shielding envelope and elements of radiological protection at the TRIUMF-ARIEL facility

The Advanced Rare Isotope Laboratory (ARIEL) is currently under construction at TRIUMF. ARIEL's mission is to supply existing experiments with more diverse and more intense radioactive ion beams (RIB) produced via the Isotope Separation On-Line (ISOL) method. The drivers inducing the nuclear reactions at ARIEL include a 500 MeV proton beam from the main cyclotron as well as a 35 MeV electron beam with the intent of simultaneous operation using two separate additional target stations. The generated RIB will be made available to experiments in condensed matter and subatomic physics as well as practical applications such as medical isotopes for life sciences research.This work details the various simulations performed using the Monte Carlo (MC) particle transport and interaction code FLUKA. The code was systematically employed to predict prompt and residual radiation levels to characterize the radiation fields generated via the irradiation of various types of targets. An iterative combined development process between CAD-based engineering of the shielding envelope, nuclear physics optimization of the target system and particle tracing simulations was established.Preliminary simulation studies resulted in the selection of shielding materials and respective thicknesses with the goal of maximizing attenuation while mitigating residual activation. The results provide clear operational constraints and aid in determination of expected dose rates outside of shielding in high occupancy areas. A series of optimization steps followed the preliminary work, testing various parameters including beam power, target material and shielding configurations. These results were evaluated considering technical feasibility, safety, and economic impacts on ARIEL construction and eventual operation.Although the project, in its infancy, is expected to proceed through stages of increasing complexity, the shielding and radiation transport modeling completed to date helps to define and validate nominal operation and failure scenario procedures for all future project stages.

Концептуальный подход к созданию комплексной системы радиационной защиты в условиях воздействия высокодозных полей ионизирующего излучения

The general approaches and criteria for substantiating the complex system of radiation protection (RP) of a human operator in the conditions of work in high-dose fields of ionizing radiation are considered. When planning work in such conditions, it is advisable to consider a set of measures of an organizational, technical and medical nature. Each activity has its measures own limits to reduce the dose load on the human operator or the development of adverse effects of radiation, and in some cases only a combination of them can give a certain protective effect, allowing to carry out the necessary activities in such conditions. If an operator works in mobile technical facilities (for example, a bulldozer, a caterpillar all-terrain vehicle, a helicopter, etc.) an important place is occupied by the issue of strengthening the technical component of the RP, primarily by engineering the design of additional shield elements. The biomedical rationale for the optimality of such protection is givenensuring maximum protection of vital organs, in the first place, red bone marrow, a significant volume of which is concentrated in the bones in the lumbar vertebrae, sacrum and pelvis. Several examples of the performance of professional activity of operator in the conditions of high-dose ionizing radiation fields and an expert evaluation of the limiting capabilities of the technical and medical component of the integrated RP are considered.

Hypervelocity impact of PrintCast 316L/A356 composites

Shielding elements used to protect against micrometeoroids and orbital debris (MMOD) (e.g., standard and stuffed Whipple shields, multi-shock shields) typically incorporate thin bumper sheets that intercept and vaporize incident MMOD traveling at speeds in excess of several km/s. In some applications, however, space limitations prevent the use of large stand-offs, and components must instead be protected by a single monolithic shielding element. Electronics, for example, are often only protected by their housing. With such applications in mind, we describe a class of spatially efficient composite shielding elements fabricated using a hybrid additive manufacturing approach termed PrintCasting. The PrintCast process consists of two steps: First selective laser melting is used to fabricate a lattice preform in the shape of the final component. Next this preform is infiltrated with a liquid metal that has a melting point lower than that of the lattice. The resulting solidified part is a periodic interpenetrating composite in which each constituent forms a continuous network. Using a combination of hypervelocity impact experiments and shock transmission calculations, we demonstrate that these interpenetrating composite shielding elements mitigate spallation and other failure modes through multiple internal shock reflections at the buried heterophase interfaces.