scholarly journals Characteristics of a Magnetic Bulk Thermostat for Granular Gas Investigations in Microgravity

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Masato Adachi ◽  
Michael Balter ◽  
Xiang Cheng ◽  
Jörg Drescher ◽  
Xiaotian Li ◽  
...  

AbstractA magnetic thermostat employing soft-ferromagnetic particles and a varying magnetic field has been developed to investigate a homogeneous granular gas system in microgravity. While the thermostat’s mechanism of creating homogeneous distribution of the particles was shown earlier, its characteristics have not been understood well due to limited access to a microgravity environment. Therefore, a parametric study by numerical simulation based on the discrete element method is carried out in this paper to evaluate effects of tunable parameters in the thermostat. The result shows the capability of the system and provides a wide range of options and improvements for future experiments. Moreover, it predicts that the thermostat allows variation of homogeneity and excitation level of the granular gas just by changing the magnetic parameters without using any mechanical means. In addition, the suggested improvement is experimentally implemented and evaluated in a drop tower test.

2016 ◽  
Vol 21 (2) ◽  
pp. 365-377
Author(s):  
Luis Eduardo Rojas Murcia ◽  
Juan E. Carvajal Cogollo ◽  
Javier Alejandro Cabrejo Bello

<p>Con el fin de caracterizar la distribución horizontal (repartición de los hábitats) y la utilización del recurso alimentario (tipo y tamaño de las presas) del ensamblaje de reptiles del bosque seco estacional al norte de la región Caribe de Colombia, en el departamento del Cesar, se realizaron cinco salidas de campo con una duración de doce días cada una. Los muestreos se realizaron en jornadas diurnas y nocturnas, en un diseño de transectos replicados a lo largo de diferentes hábitats que incluyeron: pastizales, bordes e interiores de bosque. Se realizaron análisis descriptivos de uso de hábitat en un perfil de vegetación por cada época climática y análisis de amplitud y sobreposición de nicho. Se registraron 38 especies de 14 familias del orden Squamata. Las especies se distribuyeron de manera homogénea entre zonas abiertas y boscosas. Se encontraron registros de 31 categorías de presa en 109 estómagos de seis especies de serpientes (61 estómagos) y siete de lagartos (48 estómagos) con un porcentaje de estómagos vacíos de 38 %. Las presas de mayor importancia para los lagartos fueron Coleoptera y Araneae, y para las serpientes fueron los anfibios. La mayoría de las especies presentaron un amplio espectro de dieta y entre especies similares, como entre Anolis auratus y A. gaigei, se presentó uso de recursos similares. En síntesis, el ensamblaje de reptiles presentó una distribución homogénea en los hábitats evaluados (áreas abiertas y boscosas) y el recurso alimentario fue variado entre las diferentes especies; la estacionalidad de la zona presenta un papel fundamental en la estructura del ensamblaje de reptiles, presentándose menos abundancia durante la época seca, tanto en las áreas abiertas como en las boscosas.</p><p><strong>Reptiles from the Seasonal Dry Forest the Caribbean Region: Distribution of Habitat and use of Food Resource</strong></p><p><strong>ABSTRACT</strong></p><p>We assessed the horizontal distribution and use of the food resource of the reptile’s assemblage of the seasonal tropical dry forest in the North of the Caribbean region of Colombia, department of Cesar. Five fieldtrips of 12 days each were performed, sampling was diurnal and nocturnal, following a transect design replicated along different habitats including grasslands, edge and interior of forest. We performed descriptive analyzes of habitat use, using a profile of vegetation by each climatic period; we also did an analysis of amplitude and niche overlap. We recorded 38 species of 14 families of the Squamata order. Species distributed evenly between open and forested areas. Record of 31 categories of prey in 109 stomachs of six species snakes (61 stomachs) and seven of lizards (48 stomachs) with a percentage of empty stomachs of 38 % was found. The preys of greater importance for the lizards were Coleoptera and Araneae and for snakes, amphibians. Most of the species presented a wide range of diet and between similar species, such as Anolis auratus and A. gaigei, found a similar use of resources. In summary, the assembly of reptiles presented a homogeneous distribution in the habitats evaluated (forested and open areas) and the food resource varied among the different species; the seasonality of the area plays a fundamental role on the structure of this reptile assembly with less abundance during the dry season in both, open and forested habitats.</p>


2017 ◽  
Vol 4 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Thomas Blanks ◽  
Nicholas Woodier ◽  
Bryn Baxendale ◽  
Mark Fores ◽  
Lynn Fullerton

ObjectiveTo evaluate the efficacy of simulation-based techniques to prospectively assess developing polices prior to implementation.MethodsA self-selected sample of nursing staff from a local, acute hospital reviewed a draft intravenous drug administration policy before simulating drug administration of either an infusion or direct injection. The participants completed a postsimulation questionnaire regarding the new policy and simulation, took part in a semistructured interview and were observed during the simulation with their consent.Results10 staff attended the simulation. The emergent themes identified a wide range of factors relating to the everyday usability and practicalities of the policy. There were issues surrounding inconsistent language between different clinical teams and training requirements for the new policy.ConclusionSimulation, using simple scenarios, allows the safe evaluation of new policies before publication to ensure they are appropriate for front-line use. It engages staff in user-centred design in their own healthcare system.


2019 ◽  
Vol 35 (21) ◽  
pp. 4442-4444 ◽  
Author(s):  
Jia-Xing Yue ◽  
Gianni Liti

Abstract Summary Simulated genomes with pre-defined and random genomic variants can be very useful for benchmarking genomic and bioinformatics analyses. Here we introduce simuG, a lightweight tool for simulating the full-spectrum of genomic variants (single nucleotide polymorphisms, Insertions/Deletions, copy number variants, inversions and translocations) for any organisms (including human). The simplicity and versatility of simuG make it a unique general-purpose genome simulator for a wide-range of simulation-based applications. Availability and implementation Code in Perl along with user manual and testing data is available at https://github.com/yjx1217/simuG. This software is free for use under the MIT license. Supplementary information Supplementary data are available at Bioinformatics online.


2016 ◽  
Vol 30 (03) ◽  
pp. 1550261 ◽  
Author(s):  
Roberto N. Duarte ◽  
Jonas D. Faria ◽  
Crystopher Brito ◽  
Nathalia C. Veríssimo ◽  
Noé Cheung ◽  
...  

The dependence of tensile properties on the length scale of the dendritic morphology of Al–Cu, Al–Ag and Al–Ag–Cu alloys is experimentally investigated. These alloys were directionally solidified (DS) under a wide range of cooling rates [Formula: see text], permitting extensive microstructural scales to be examined. Experimental growth laws are proposed relating the primary dendritic arm spacing, [Formula: see text] to [Formula: see text] and tensile properties to [Formula: see text]. It is shown that the most significant effect of the scale of [Formula: see text] on the tensile properties is that of the ternary alloy, which is attributed to the more homogeneous distribution of the eutectic mixture for smaller [Formula: see text] and by the combined reinforcement roles of the intermetallics present in the ternary eutectic: Al2Cu and nonequilibrium Ag3Al.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Abbas Mahmoudabadi

Hazardous material transportation is one of the main concerns due to the nature of hazardous materials and their incident impacts. In general, transport risk is a main attribute to develop mathematical models for hazardous material routing problem as well as network designing or improving road safety. This paper presents a chaotic-simulation based model to determine the high selected links to improve road network quality for hazardous material transportation, in which risk is considered as a chaotic variable over the network whereas a simulation technique has been applied to cover a wide range of selecting paths. A real road network, consists of fifty-nine nodes and eighty two-way edges, is used for running the mathematical model and checking validation. Due to the large amounts of hazardous material transported by trucks, the proposed methodology is focused on fuel transportation, and high selected list of edges (links) has been obtained to improve road safety. Sensitivity analysis revealed that using different seeds for generating transport risk has no significant effects on finding the most frequent paths and high selected edges.


2010 ◽  
Vol 653 ◽  
pp. 175-219 ◽  
Author(s):  
MEHEBOOB ALAM ◽  
V. K. CHIKKADI

Probability distribution functions of fluctuation velocities (P(ux) and P(uy), where ux and uy are the fluctuation velocities in the x- and y-directions, respectively; the gravity is acting along the periodic x-direction and the flow is bounded by two walls parallel to the y-direction) and the density and the spatial velocity correlations are studied using event-driven simulations for an inelastic smooth hard disk system undergoing gravity-driven granular Poiseuille flow (GPF). It is shown that for GPF with smooth and/or perfectly rough walls the Maxwellian/Gaussian is the leading-order distribution over a wide range of densities in the quasi-elastic limit, which is a surprising result, especially for a dilute granular gas for which the Knudsen number belongs to the transitional flow regime. The signature of wall-roughness-induced dissipation mainly shows up in the P(ux) distribution in the form of a sharp peak for negative velocities in the near-wall region. Both P(ux) and P(uy) distributions become asymmetric with increasing dissipation at any density, and the emergence of density waves, which appear in the form of sinuous wave/slug at low-to-moderate values of mean density, makes these asymmetries stronger, especially in the presence of a slug. At high densities, the flow degenerates into a dense plug (where the density approaches its maximum limit and the shear rate is negligibly small) around the channel centreline and two shear layers (where the shear rate is high and the density is low) near the walls. The distribution functions within the shear layer follow the characteristics of those at moderate mean densities. Within the dense plug, the high-velocity tails of both P(ux) and P(uy) appear to undergo a transition from Gaussian in the quasi-elastic limit to power-law distributions at large inelasticity of particle collisions. For dense flows, it is shown that although the density correlations play a significant role in enhancing the velocity correlations when the collisions are sufficiently inelastic, they do not induce velocity correlations when the collisions are quasi-elastic for which the distribution functions are close to Gaussian. The combined effect of enhanced density and velocity correlations around the channel centreline with increasing inelastic dissipation seems to be responsible for the emergence of non-Gaussian high-velocity tails of distribution functions.


2008 ◽  
Vol 58 (12) ◽  
pp. 2453-2465 ◽  
Author(s):  
M. C. Gromaire ◽  
M. Kafi-Benyahia ◽  
J. Gasperi ◽  
M. Saad ◽  
R. Moilleron ◽  
...  

Settling velocities of TSS and of particulate pollutants (COP, PDCO, PTKN, PCu, PPb, PZn, PPAH) measured on a wide range of wet weather flow (WWF) samples collected at different levels of the Parisian combined sewer system are reported. The recorded V30 (0.01 to 0.1 mm.s-1) and V50 (0.09 to 0.6 mm.s−1) values exceed by a factor 10 those of dry weather sewage and also exceed the values measured for pavement runoff. These values lie however often below the 0.28 mm.s−1 reference value considered in France for the design of WWF settling facilities. A decrease in settleability is observed between a small upstream catchment and larger scaled downstream catchments. The settling behaviour of particulate pollutants varies depending on the considered parameter and can differ significantly from the TSS behaviour, due to a non homogeneous distribution of micropolluants over the different classes of particles. PZn and PTKN appear far less settleable than TSS, whereas PPAH show higher settleability.


2017 ◽  
Vol 17 (7&8) ◽  
pp. 623-635
Author(s):  
Leonardo Novo ◽  
Dominic Berry

We describe an improved version of the quantum algorithm for Hamiltonian simulation based on the implementation of a truncated Taylor series of the evolution operator. The idea is to add an extra step to the previously known algorithm which implements an operator that corrects the weightings of the Taylor series. This way, the desired accuracy is achieved with an improvement in the overall complexity of the algorithm. This quantum simulation method is applicable to a wide range of Hamiltonians of interest, including to quantum chemistry problems.


Author(s):  
Mohamed Qawaqzeh ◽  
Roman Zaitsev ◽  
Oleksandr Miroshnyk ◽  
Mykhailo Kirichenko ◽  
Dmytro Danylchenko ◽  
...  

In the article the circuit design solution of DC-DC regulated resonant converter has been proposed for using with hybrid photovoltaic modules which has cooling equipment and solar concentrators in order to maximize electric power generating by such module. By using computer simulation based on multiple iterations algorithm we significantly increase the accuracy of determining the resonance circuit optimal parameters for build up DC–DC converters to work in a wide range of electric powers. Based on optimal values of the resonance LLC scheme parameters, achived by numerical calculation it can be show high values of electrical energy transformation efficiency for photovoltaic energy station equipped with high efficiency hybrid photovoltaic modules.  Implementation of microprocessor-based control into design of DC–DC back-boost converters create a new possibility to build control algorithms for increase reliability and conversion efficiency, rapid and precision stabilization of maximum power point, implementation network monitoring of photovoltaic modules, converters itself and the whole photovoltaic station parameters.


2021 ◽  
Vol 11 (3) ◽  
pp. 413-427
Author(s):  
Hendri Purwadi ◽  
Katrina Breaden ◽  
Christine McCloud ◽  
Satriya Pranata

Background: Two common triage systems have been widely used in mass casualty incidents (MCIs) and disaster situations, namely START (simple triage algorithm and rapid treatment) and SALT (sort, assess, lifesaving, intervention, and treatment/transport). There is currently controversy regarding the effectiveness of SALT over the START triage system.Purpose: This systematic review aims to compare the accuracy of the SALT and START triage systems in disaster and MCI settings.Methods: The literature was searched using a systematic search strategy for articles published from 2009 to 2020 in the Medline, CINAHL, Web of Science, Scopus, PubMed, ProQuest databases, and the grey literature. This review included simulation-based and medical record-based studies investigating the accuracy and applicability of the SALT and START triage systems in adult and child populations during MCIs and disasters. All types of studies were included. The PRISMA flowchart was used to retain the articles, and the Joanna Briggs Institute critical appraisal tools were used to assess the quality of the reviewed studies.Results: Of 1,450 articles identified in the search, 10 articles were included. It was found that the START triage system had a wide range and inconsistent levels of accuracy (44% to 94.2%) compared to the SALT triage system (70% to 83%). The under-triage error of the START triage system ranged from 2.73% to 20%, which was slightly lower than the SALT triage system (7.6% to 23.3%). The over-triage error of the START triage system (2% to 53%) was slightly higher than the SALT triage system (2% to 22%). However, the time taken to apply START triage system (70 to 72.18 seconds) was faster than for the SALT triage system (78 seconds).Conclusion: The START triage system was simpler and faster than SALT. Conversely, the SALT triage system appeared to be slightly more accurate, more consistent, and had a lower rate of under- and over-triage error than START. It appears that neither the SALT nor the START triage system is superior to the other. Further research is needed to establish the most appropriate disaster and MCI triage system, especially for the Indonesian context. 


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