rss_2.0Physics FeedSciendo RSS Feed for Physics Feed analysis of spatial variability of the liquefaction potential – Case study of a site located in Algiers (Algeria)<abstract><title style='display:none'>Abstract</title><p>The city of Algiers (Algeria) is a highly seismic area, and therefore, soil liquefaction poses a major concern for structures resting on sandy soil. A campaign of 62 static penetration tests or cone penetrometer tests (CPT) was carried out on a site located in the commune of Dar El Beïda in Algiers. The soil Liquefaction Potential Index (LPI) values were assessed, for each borehole, based on the simplified procedure of Seed and Idriss. On the other hand, the geographic information system and geostatistical analysis were used to quantify the risk of soil liquefaction at the studied site. It is worth mentioning that the (LPI) was taken as a regionalized variable. In addition, the experimental variogram was modeled on the basis of a spherical model. Also, the interpolation of the LPI values in the unsampled locations was performed by the Kriging technique using both isotropic and anisotropic models. Kriging standard deviation maps were produced for both cases. The cross-validation showed that the anisotropic model exhibited a better fit for the interpolation of the values of the soil liquefaction potential. The results obtained indicated that a significant part of the soil is liable to liquefy, in particular in the northwestern region of the study area. The findings suggest that there is a proportional relationship between the risk of liquefaction and the increase or decrease in seismic acceleration.</p></abstract>ARTICLE2021-06-11T00:00:00.000+00:00Electrical impedance to easily discover undeclared freeze-thaw cycles in slaughtered bovine meat<abstract><title style='display:none'>Abstract</title><p>A portable electrical impedance spectroscopy device was developed to monitor the bioimpedance resistive component of bovine meat by injecting a sinusoidal current of 1 mA at 65 kHz. Both right and left longissimus dorsi muscles were trimmed from 4 slaughtered cows. The left muscle portions were frozen to −18 °C for 7 days while the right ones were meantime maintained at 5 °C. Mean value of impedance per length (Ω/cm) of frozen and thawed left samples was 31% lower than that of right non-frozen one (P = 0.0001). It was concluded that the device is reliable for monitoring the maturation of beef meat in situ with the possibility of revealing undeclared freeze-thaw cycles.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Segmental volume and circulatory changes that occur in humans and Rhesus monkeys during 4 hour, −6 degree head down tilt<abstract><title style='display:none'>Abstract</title><p>Nonhuman primates are often used to investigate physiologic processes that occur in man during aerospace/cardiovascular orthostatic research. Few studies have compared nonhuman primates and man under identical test conditions to assess the degree of similarity between the two species. Impedance plethysmography was used to measure calf, thigh, pelvic, thoracic, upper arm, and lower arm volume changes in eight rhesus (Macacca Mulatta) monkeys and twelve human subjects during four hour exposures to −6 degree head down tilt (HDT).</p></abstract>ARTICLE2021-04-17T00:00:00.000+00:00Electrical bioimpedance: from the past to the future<abstract><title style='display:none'>Abstract</title><p>This year, 2021, marks the “coming of age” for JoEB with its indexing in PubMed Central. It is also a century since some of the earliest studies on tissue impedance. This editorial briefly reviews the time-line of research in the field to mark this occasion.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Optimization of Po determination in soil<abstract><title style='display:none'>Abstract</title><p>In recent years, naturally occurring radioactive materials (NORM) have become an important topic from the perspective of environmental protection. The list of isotopes that should be monitored in the environment is constantly growing as new amendments to international legislation are introduced. One of the often studied NORM elements is <sup>210</sup>Po. In this study, a process of elaborating of a new method of <sup>210</sup>Po determination in soil was presented. In the proposed method, several analytical aspects, like the influence of silica decomposition or optimization of an electrode material, were revised. The obtained procedure allows performance of complete radiochemical analysis in a single day, with the chemical efficiency of over 85% and great reduction of costs. Further, the influence of the use of phosphate fertilizers on polonium concentration in soil was also confirmed.</p></abstract>ARTICLE2021-06-08T00:00:00.000+00:00Design and fabrication of I seeds for brachytherapy using capillary-based microfluidic technique<abstract><title style='display:none'>Abstract</title><p>A new kind of <sup>125</sup>I seeds with a core-shell structure were synthesized by an easy assembling–disassembling coaxial capillaries microfluidic device. The dose distribution of a <sup>125</sup>I brachytherapy source fabricated by arranging six <sup>125</sup>I seeds collinearly within a cylindrical titanium capsule was simulated by modelling the source in a water phantom using Monte Carlo N-Particle Transport code. The influence of the motion and the core size of the <sup>125</sup>I seeds on the dose distribution was also studied in this work.</p></abstract>ARTICLE2021-06-08T00:00:00.000+00:00Validation of transient time method to calibrate oil flow meters in closed conduits using I as the radiotracer<abstract><title style='display:none'>Abstract</title><p>To assure the credibility of commodity transfer operations in the oil and gas industry, calibrated flow meters are used to quantify the movement of fluids in the pipelines. The purpose of this paper is to validate the transient time method (TTM) to calibrate oil flow meters installed in restricted areas, using the <sup>123</sup>I-labelled oil as a radiotracer. Traditionally, as proposed by the standard ISO 2975-7:1977 [<xref ref-type="bibr" rid="j_nuka-2021-0009_ref_001">1</xref>] for experiments in an aqueous medium, the TTM is employed by positioning two detectors at separate locations. However, in industrial plants, it is not always possible to install detectors at the distances recommended by the ISO 2975-7. The method proposed in this paper uses four scintillator detectors separated one from each other by 0.30 m and three injections containing 5.0 ml of <sup>123</sup>I-labelled oil. The experiments were carried out in an oil flow rig with a turbulent flow profile. The results have reached an uncertainty which is lower than 1.0%.</p></abstract>ARTICLE2021-06-08T00:00:00.000+00:00Production of actinium-225 from a (n,p) reaction: Feasibility and pre-design studies<abstract><title style='display:none'>Abstract</title><p>Actinium-225 is used in nuclear medicine for the treatment of malignant tumours. It can be applied to produce Bi-213 in a reusable generator or can be used alone as an agent for radiation therapy, in particular for targeted alpha therapy. However, the availability of Ac-225 for worldwide use, particularly in low- and middle-income countries, is limited. We present a feasibility study employing GATE, an open-source Monte Carlo simulation toolkit, on the production of Ac-225 from a neutron generator. This work suggests that a design consisting of three concentric cylinders, the innermost a Cf-252 neutron source, the middle nickel cylinder acting as a proton-producing target and the outer cylinder a RaCl<sub>2</sub> target may provide a feasible design outline for an Ac-225 generator.</p></abstract>ARTICLE2021-06-08T00:00:00.000+00:00Independent verification of treatment planning system calculations<abstract><title style='display:none'>Abstract</title><sec><title style='display:none'>Purpose</title><p>According to the available international recommendations, at least one independent verification of the calculations of number of monitor unit (MU) is required for every patient treated by teleradiotherapy. The aim of this study was to estimate the differences of dose distributions calculated with two treatment planning systems: Eclipse (Varian) and Oncentra MasterPlan (Elekta).</p></sec><sec><title style='display:none'>Materials and methods</title><p>The analysis was performed for 280 three-dimensional conformal radiotherapy treatment (3D-CRT) plans with photon beams from Varian accelerators: CL 600C/D X6 MV (109 plans), CL 2300C/D X6 MV (43 plans), and CL 2300C/D X15 MV (128 plans). The mean doses in the planning target volume (PTV) and doses at the isocenter point obtained with Eclipse and Oncentra MasterPlan (OMP) were compared with Wilcoxon matched-pairs signed rank test. Additionally, the treatment planning system (TPS) calculations were compared with dosimetric measurements performed in the inhomogeneous phantom.</p></sec><sec><title style='display:none'>Results</title><p>Data were analysed for 6 MV plans and for 15 MV plans separately, independently of the treatment machine. The dose values calculated in Eclipse were significantly (<italic>p</italic> &lt;0.001) higher compared to calculations of OMP system. The average difference of the mean dose to PTV was (1.4 ± 1.0)% for X6 MV and (2.5 ± 0.6)% for X15 MV. Average dose disparities at the isocenter point were (1.3 ± 1.9)% and (2.1 ± 1.0)% for X6 MV and X15 MV beams, respectively. The largest differences were observed in lungs, air cavities, and bone structures. Moreover the variation in dosimetric measurements was less as compared to Eclipse calculations.</p></sec><sec><title style='display:none'>Conclusions</title><p>OMP calculations were introduced as the independent MU verification tool with the first action level range equal to 3.5%.</p></sec></abstract>ARTICLE2021-06-08T00:00:00.000+00:00Erratum to “Radon incomparison tests – Katowice, 2016” [Nukleonika 2020;65(2):127-132, doi:10.2478/nuka-2020-0020] the Approach to Understand a Trash-to-Gas Experiment in a Microgravity Environment<abstract> <title style='display:none'>Abstract</title> <p>The Orbital Syngas/Commodity Augmentation Reactor (OSCAR) project investigated hardware and engineering development for waste conversion operations related to trash deconstruction and repurposing for long duration space missions. Operations of the trash-to-gas system were investigated to compare microgravity (μg) and Earth gravity environments. The OSCAR system has been demonstrated in other μg platforms, but here the performance and results on the Blue Origin New Shepard Suborbital Vehicle are discussed. The OSCAR suborbital operation demonstrated the introduction of trash into a high temperature reactor for solid to gas conversion, ignition of mixed trash feedstock, combustion during μg, and subsequent gas collection processes in a flight automated sequence. An oxygen (O<sub>2</sub>)- and steam-rich environment was created within the reactor for ignition conditions, and the product gases were quantified to verify the reaction product composition. This paper focuses on the chemistry processes of the reactor, and gas and solid product analysis of the μg and gravity conditions. The gas production, reactor thermal profile, and mass and carbon conversion results validated confidence in the system design to continue the advancement of this technology for future spaceflight implementations.</p> </abstract>ARTICLE2021-05-24T00:00:00.000+00:00Shared Metabolic Remodeling Processes Characterize the Transcriptome of within Various Suborbital Flight Environments<abstract> <title style='display:none'>Abstract</title> <p>The increasing availability of flights on suborbital rockets creates new avenues for the study of spaceflight effects on biological systems, particularly of the transitions between hypergravity and microgravity. This paper presents an initial comparison of the responses of Arabidopsis thaliana to suborbital and atmospheric parabolic flights as an important step toward characterizing these emerging suborbital platforms and their effects on biology. Transcriptomic profiling of the response of the Arabidopsis ecotype Wassilewskija (WS) to the aggregate suborbital spaceflight experiences in Blue Origin New Shepard and Virgin Galactic SpaceShipTwo revealed that the transcriptomic load induced by flight differed between the two flights, yet was biologically related to traditional parabolic flight responses. The sku5 skewing mutant and 14-3-3κ:GFP regulatory protein overexpression lines, flown in the Blue Origin and parabolic flights, respectively, each showed altered intra-platform responses compared to WS. An additional parabolic flight using the F-104 Starfighter showed that the response of 14-3-3κ:GFP to flight was modulated in a similar manner to the WS line. Despite the differing genotypes, experimental workflows, flight profiles, and platforms, differential gene expression linked to remodeling of central metabolic processes was commonly observed in the flight responses. However, the timing and directionality of differentially expressed genes involved in the conserved processes differed among the platforms. The processes included carbon and nitrogen metabolism, branched-chain amino acid degradation, and hypoxic responses. The data presented herein highlight the potential for various suborbital platforms to contribute insights into biological responses to spaceflight, and further suggest that in-flight fixation during suborbital experiments will enhance insights into responses during each phase of flight.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00Research Flights on Blue Origin's New Shepard<abstract> <title style='display:none'>Abstract</title> <p>Blue Origin's New Shepard launch vehicle made its first flight above the Kármán Line, returning safely to Earth in November 2015. At the time when this paper is being written (February 2021), the system has conducted 14 flights, including 10 with research and education payloads aboard. More than 100 payloads have exercised a wide range of capabilities and interfaces, from small cubesat-form factor student payloads to large custom payloads of nearly 100 kg. Investigations have spanned a wide range of high-altitude and microgravity research objectives, as well as raising technology readiness level (TRL) on diverse hardware. This paper summarizes New Shepard's payload missions to date, and presents standardized and custom accommodations, both in the shirtsleeve cabin and directly exposed to the space environment.</p> </abstract>ARTICLE2021-03-20T00:00:00.000+00:00APL JANUS System Progress on Commercial Suborbital Launch Vehicles: Moving the Laboratory Environment to Near Space<abstract> <title style='display:none'>Abstract</title> <p>Multiple private companies are building suborbital reusable launch vehicles possessing vastly different designs. Many of these companies originally focused on space tourism; however, revolutionary applications for scientific and engineering research as well as technology demonstrations and instrument development are emerging. The dramatic reduction in cost over traditional launch systems as well as a guaranteed (and rapid) safe payload return enable many new launch vehicle applications. These new capabilities will essentially move the laboratory environment up to the edge of space. To make use of these novel launch vehicles, the John Hopkins University Applied Physics Laboratory has established a Commercial Suborbital Program with a core system (JANUS) to support and enable many future suborbital missions. This program has already conducted six suborbital flight missions to establish vehicle interfaces and analyze the suitability and limits of each flight environment. Additionally, this program has also been selected by the NASA Flight Opportunities Program for five additional operational suborbital missions. Here we present the results of our completed missions as well as descriptions of future selected missions scheduled for 2021–2023.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00The Adhesive Response of Regolith to Low-Energy Disturbances in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>Small, airless bodies are covered by a layer of regolith composed of particles ranging from μm-size dust to cm-size pebbles that evolve under conditions very different than those on Earth. Flight-based microgravity experiments investigating low-velocity collisions of cm-size projectiles into regolith have revealed that certain impact events result in a mass transfer from the target regolith onto the surface of the projectile. The key parameters that produce these events need to be characterized to understand the mechanical behavior of granular media, which is composed of the surfaces of small bodies. We carried out flight and ground-based research campaigns designed to investigate these mass transfer events. The goals of our experimental campaigns were (1) to identify projectile energy thresholds that influence mass transfer outcomes in low-energy collision events between cm-size projectiles and μm-size regolith, (2) to determine whether these mass transfer events required a microgravity environment to be observed, and (3) to determine whether the rebound portion of these collision events could be replicated in a laboratory drop tower environment. We found that (1) mass transfer events occurred for projectile rebound accelerations &lt;7.8 m/s<sup>2</sup> and we were unable to identify a corresponding impact velocity threshold, (2) mass transfer events require a microgravity environment, and (3) ourdrop tower experiments were able to produce mass transfer events. However, drop tower experiments do not exactly reproduce the free-particle impacts and rebound of the long-duration microgravity experiments and yielded systematically lower amounts of the overall mass transferred.</p> </abstract>ARTICLE2021-01-29T00:00:00.000+00:00Liquid Propellant Mass Measurement in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>The Modal Propellant Gauging (MPG) experiment has demonstrated sub-1% gauging accuracy under laboratory conditions on both flight hardware and subscale tanks. Recently, MPG was adapted for flight on Blue Origin's New Shepard vehicle and has flown twice, achieving equilibrated, zero-g surface configurations of propellant simulant at three different fill fractions. Flight data from MPG missions on New Shepard P7 and P9 show agreement between known and measured propellant levels of 0.3% for the fill fractions investigated in the present study. Two approaches for estimating zero-g propellant mass are described here. Both approaches rely on measuring shifts in modal frequencies of a tank excited by acoustic surface waves and subject to fluid mass loading by the propellant. In the first approach, shifts in the lowest mode frequency (LMF) are measured and associated with liquid fill-level changes. In the second approach, 1-g modal spectra at a range of known fill levels are used in a cross-correlation calculation to predict fill levels associated with a zero-g modal spectrum. Flight data for both approaches are consistent with finite element predictions using a simple fluid–structure interaction model. In both settled and unsettled microgravity environments, MPG meets or exceeds NASA Roadmap goals for in-space propellant mass gauging.</p> </abstract>ARTICLE2021-02-26T00:00:00.000+00:00A Rapid Fabrication Methodology for Payload Modules, Piloted for the Observation of Queen Honey Bees () in Microgravity<abstract> <title style='display:none'>Abstract</title> <p>Microgravity experiment modules for living organisms have been instrumental to space research, yet their design remains complex and costly. As the private space sector enables more widely available payloads for researchers, it is increasingly necessary to design experimental modules innovatively so that they are proportionately accessible. To ease this bottleneck, we developed a rapid fabrication methodology for producing custom modules compatible with commercial payload slots. Our method creates a unified housing geometry, based on a given component layout, which is fabricated in a digital design and subtractive manufacturing process from a single lightweight foam material. This module design demonstrated a 25–50% reduction in chassis weight compared with existing models, and is extremely competitive in manufacturing time, simplicity, and cost. To demonstrate the ability to capture data on previously limited areas of space biology, we apply this methodology to create an autonomous, video-enabled module for sensing and observing queen and retinue bees aboard the Blue Origin New Shepard 11 (NS-11) suborbital flight. To explore whether spaceflight impacts queen fitness, results used high-definition visual data enabled by the module's compact build to analyze queen-worker regulation under microgravity stress (n = 2, with controls). Overall, this generalizable method for constructing experimental modules provides wider accessibility to space research and new data on honey bee behavior in microgravity.</p> </abstract>ARTICLE2021-06-01T00:00:00.000+00:00Design of software-defined network experimental teaching scheme based on virtualised Environment<abstract><title style='display:none'>Abstract</title><p>Aiming to address the shortage of experimental resources, the high cost of large-scale deployment of hardware experimental environment and the difficulty for students to get started in the software-defined network (SDN) course, this article proposes an SDN experimental teaching scheme based on the virtualised environment, and gives a specific experimental scheme design. The scheme utilises virtualisation technology to build a SDN experimental environment quickly, uses a lightweight network simulation platform – that goes by the name of Mininet – to build the SDN network and uses open-source controller Floodlight for centralised control of the SDN network. The scheme is mainly divided into three phases: basic, improvement and synthesis. In the basic phase, experimental projects mainly include the study of SDN basic concepts and the use of relevant tools; in the improvement phase, experimental projects mainly include the use of SDN flow table, group table, etc; in the synthetic phase, we design two innovative experimental projects that use computational intelligence technology to achieve efficient load balancing and accurate malicious attack detection. The difficulty of each phase is increasing. The constantly evolving levels of difficulty allow the individual needs of students with different levels to be met, thereby improving the effect of SDN experimental teaching and cultivating innovative SDN talents.</p></abstract>ARTICLE2021-05-25T00:00:00.000+00:00The Comprehensive Diagnostic Method Combining Rough Sets and Evidence Theory<abstract><title style='display:none'>Abstract</title><p>To solve the difficulties in practice caused by the subjectivity, relativity and evidence combination focus element explosion during the process of solving the uncertain problems of fault diagnosis with evidence theory, this paper proposes a fault diagnosis inference strategy by integrating rough sets with evidence theory along with the theories of information fusion and mete-synthesis. By using rough sets, redundancy of characteristic data is removed and the unrelated essential characteristics are extracted, the objective way of basic probability assignment is proposed, and an evidence synthetic method is put forward to solve high conflict evidence. The method put forward in this paper can improve the accuracy rate of fault diagnosis with the redundant and complementary information of various faults by synthesizing all evidences with the rule of the composition of evidence theory. Besides, this paper proves the feasibility and validity of experiments and the efficiency in improving fault diagnosis.</p></abstract>ARTICLE2021-05-25T00:00:00.000+00:00Biochemical parameters variations with season, age, sex, parity and pregnancy in crossbred goats raised in Tiaret, Algeria<abstract><title style='display:none'>Abstract</title><p>The aim of this study was to determine the influence of season, age, sex, parity and gestation status on some biochemical parameters in local cross-bred goats raised in Tiaret, Algeria. Ninety cross bred local goats, from 2019 to 2020, aged between nine and seventy-two months at different physiological stage were used. Animals belong to different farms in Tiaret located at the north-west Algeria (35°22’ N, 1°19’ E). The mean values of triglycerides, creatinine and calcium were significantly (p&lt;0,05) higher in winter than in spring. The physiological state of the goat had a significant influence (p&lt;0,05) on cholesterol, urea, total proteins, calcium and phosphorus, with a high average values in non-pregnant goats, while triglycerides and globulin had significant higher values in postpartum and pregnant femals, respectively. In our work, parity had a significant influence (p&lt;0,05) on cholesterol, calcium and phosphorus, with high average values in young goats and a significant influence (p&lt;0,05) on triglycerides and creatinine with high average values in primiparous ones. Age significantly influenced (p&lt;0,05) cholesterol, triglycerides, total protein, calcium and globulin. The results obtained from this study could serve as reference values for the local goats and other regions or countries with similar climatic and nutritional conditions.</p></abstract>ARTICLE2021-03-18T00:00:00.000+00:00en-us-1