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Real-time calculation of fragment velocity for cylindrical warheads

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Defence Technology（防务技术） 2019年第3期15卷 264-271页

作者： david felix Ian Colwill Elias Stipidis Institution of Engineering and Technology Stevenage England Member of British Computer Society London Institute of Electrical and Electronics Engineers London

To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches.

关键词： Initial fragment velocity Real-time simulation Cylindrical explosion

维普期刊数据库

In-situ investigation on real-time suspended sediment measurement techniques:Turbidimetry, acoustic attenuation,laser diffraction (LISST) and vibrating tube densimetry

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International Journal of Sediment Research 2018年第1期33卷 3-17页

作者： david felix Ismail Albayrak Robert Michael Boes Laboratory of Hydraulics Hydrology and Glaciology(VAW)ETH Zürich

Real-time measurements of Suspended Sediment mass Concentration（SSC） and Particle Size Distribution（PSD） are of prime importance for the investigation and management of fine-sediment related processes in surface water systems and hydraulic schemes. In a field study at the waterway of the hydropower plant（HPP） Fieschertal in the Swiss Alps, the real-time measurement performance of the following techniques and instruments were assessed based on measurements in the sediment seasons of the years 2013 and 2014:（1） turbidimetry,（2） single-frequency acoustic attenuation using a standard acoustic discharge measurement（ADM） installation,（3） laser diffraction（Laser In-Situ Scattering and Transmissometry, LISST）, and（4） vibrating tube densimetry using a Coriolis Flow and Density Meter（CFDM）.Reference SSCs were obtained from gravimetric analysis of 219 automatically pumped water *** additionally supplied PSD every minute. The median particle diameter, d50, was usually 15μm and increased occasionally to 100μm. The turbidimeter and the ADM underestimated the SSC when the transported particles were coarser than usual. Such temporary biases resulted from the poor correlation between d50and SSC at this study site. The SSCs from CFDM and LISST were not or less biased by PSD variations. Mainly due to angular and flaky particle shapes, SSC from LISST needed a correction by 79% on average. With the usually prevailing silt particles, an optical path length of 5 mm and no dilution, the SSC measurement range of LISST was limited to about 1.5 g/l. The CFDM allowed measuring higher SSC than the other investigated instruments（e.g. up to 13.5 g/l）. With a periodic offset correction, its relative SSC measurement uncertainty was < 20% for SSC≥ 1.5 g/I. To reliably measure a wide range of SSC with temporarily variable PSD, a combination of instruments is recommended: e.g. a standard LISST, a CFDM,and an automatic water sampler for gravimetric reference measurements.

关键词： Suspended sediment concentration Turbidity Acoustic attenuation Laser diffraction Coriolis flow and density meter Gravimetric analysis

Neuronal trafficking as a key to functional recovery in immune-mediated neuropathies

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Neural Regeneration Research 2024年第11期19卷 2331-2332页

作者： felix Kohle Michael Schroeter Department of Neurology University of Cologne and University Hospital CologneCologneGermany

Immune-mediated neuropathies are rare diseases of the peripheral nervous system(PNS),substantially affecting patients’functionality and quality of *** are amenable to immunomodulatory treatments,which in many cases stabilize disease progression,but long-term deficits persist in many *** long-term deficits are particularly observed in monophasic autoimmune neuropathies like Guillain-Barrésyndrome and also in chronic variants,e.g.,chronic inflammatory demyelinating neuropathy(Fadia et al.,2019).

关键词： diseases autoimmune

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Biotransformation of 6:2 fluorotelomer sulfonate(6:2 FTS)in sulfur-rich media by Trametopsis cervina

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Frontiers of Environmental Science & Engineering 2024年第9期18卷 17-26页

作者： felix Grimberg Thomas M Holsen Sujan Fernando Siwen Wang Department of Civil and Environmental Engineering Clarkson UniversityPotsdamNew York 13699USA

Biotransformation of 6:2 fluorotelomer sulfonate(6:2 FTS)by two species of white-rot fungi,Pleurotus ostreatus(***)and Trametopsis cervina(***),was investigated in a sulfurrich medium designed to stimulate production of lignin-degrading *** of 6:2 FTS was observed by *** over the study period of 30 d,but not by *** rates were comparable to those found in other studies investigating mixed culture degradation in nonsulfur limiting media,with approximately 50 mol%of applied 6:2 FTS removed after 30 *** transformation products were short-chain perfluorocarboxylic acids(PFCAs),including PFHxA(2.27 mol%),PFPeA(0.24 mol%),and PFBA(0.28 mol%).The main intermediate products include 5:2 sFTOH(16.3 mol%)and 5:3 FTCA(2.99 mol%),while 6:2 FTCA,6:2 FTuCA,and 5:2 ketone were also identified at low *** 60 mol%of detected products were assigned to the major pathway to 5:2 ketone,and 40 mol%were assigned to the minor pathway to 5:3 *** overall molar balance was found to decrease to 75 mol%by Day 30,however,was closed to near 95 mol%with a theoretical estimation for the volatile intermediates in the headspace,5:2 ketone and 5:2 *** different capabilities of the two white-rot fungal species for 6:2 FTS biotransformation in sulfur-rich media suggest that the enzyme processes of *** to de-sulfonate 6:2 FTS may be unrelated to sulfur metabolism.

关键词： White-rot fungus 6:2 fluorotelomer sulfonate(6:2 FTS) Biotransformation Sulfur-rich medium Intermediate products

The semiotics of humor in cultural trauma:a pilot study on digital methodology concerning the evolution and overcoming of trauma through humor on the example of Rick and Morty

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Language and Semiotic Studies 2024年第2期10卷 203-221页

作者： felix Poschinger Christopher Shannon University of Hamburg Hamburg20148Germany Independent TokyoJapan

This pilot study on humor in cultural trauma uses innovative digital methodologies in speech recognition and social media analysis via Postman and Python in the Twitter API v2 to propose different forms to gather and analyze empirical data on semiotics and humor to be used in a broader *** given example of humorous instances on the cultural trauma of 9/11 in the fictional sitcom Rick and Morty is limited but corroborated by a second example that is structurally different from the first:humor about 9/11 in stand-up comedy by Louis *** on the data,humor in trauma seems to undergo a 5-phase-typology related to the Kübler-Ross model of grief,which is mended by the(digital)participation of ***,we argue,both shapes the discourse on humor in trauma and overcomes the traumatic effects through humorous discourse.

关键词： cultural trauma humor theory Kübler-Ross model collective memory

Cognitive dissonance and mindset perturbations during crisis:“ecosocio-psycho-somatic”perspectives

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World Journal of Psychiatry 2024年第2期14卷 215-224页

作者： felix Tretter Henriette Löffler-Stastka Department of Systems Medicine and Healthcare Systems Bertalanffy Center for the Study of Systems ScienceVienna 1040Austria Department of Psychoanalysis and Psychotherapy Medical University ViennaVienna 1090Austria

Mandatory and restrictive health regulations during the corona pandemic caused psychic disorders in many people,which even led to clinically relevant mental *** the same time,there was gradually a polarization of opinions among the *** order to improve future pandemic management,an integrative understanding of these psychosocial processes therefore seems *** we start theoretically with the mental effects of inconsistencies of the information environment by referring to concepts such as the theory of cognitive *** a next step,we use the psychodynamic theory to understand the affective-motivational defense mechanisms underlying these cognitive states and ***,a broader theoretical framework of psychoanalysis seems to make sense,because self-referential processing also influences the style of *** this reason,we use a more comprehensive psychological systems theoretical framework model to integrate these different *** integrative view refers in part to basic knowledge of health psychology regarding the resistance of unhealthy ways of thinking and behaviors and the possibilities for interventions for *** then extend this model to a broader picture that also covers the relationship between men and their *** results in the perspective of a multidimensional socioecological theoretical framework,which as a heuristic reference model and related to other ecological approaches could also be helpful for various theoretical questions for public health,and could provide a better public understanding of health *** line with this perspective,we hypothesize that with regard to the coronavirus disease 2019 pandemic,the acceptance of public health narratives could be increased if a more consistent picture of the scientific descriptions and explanations of the pandemic-similar to the model proposed-could be provided,which would enable the understanding of the origin,course and countermeasur

关键词： Infodemic Affective-cognitive dissonance Systems model of the mind Socioecological model

Expedition to the blockchain application potential for higher education institutions

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BLOCKCHAIN-RESEARCH AND APPLICATIONS 2024年第3期5卷 53-66页

作者： Gottlieb, Matthias Deutsch, Christina Hoops, felix Pongratz, Hans Krcmar, Helmut Bavarian Minist Digital Affairs D-80333 Munich Germany Tech Univ Munich D-85478 Garching Germany TU Dortmund Univ D-44139 Dortmund Germany

In the education sector, blockchain is currently at the end of the peak of inflated expectations in Gartner's Hype Cycle. Thus, it is crucial to understand whether this technology meets the expectations of Higher Education Institutions (HEIs). We go on an expedition to identify blockchain application scenarios and its potential for HEI administration-the universities are digitalized to just 23.3%. Current information systems research addresses classifications of blockchain-based projects (application level) rather than their technical realization (protocol level). Thus, when evaluating blockchain application scenarios in HEI administration, we intensively consider the technical side of blockchain-based projects. We perform a three- step approach: (1) systematic literature review, (2) qualitative exploratory semi-structured interviews to supplement information on market-ready solutions, and (3) an evaluation of the potential of the blockchain-based projects identified, based on HEI administration requirements. We find that the leading blockchain application scenarios are credential verification and record-sharing. At the protocol level, we obtain equivocal results regarding the technical realization of projects, e.g., their underlying blockchain types and storage models. At the application level, when discussing the potential of different projects, we find that most of them address adaptability, complexity decomposition, and cost reduction requirements between HEIs; interest diversity and stakeholder collaboration between HEIs and business actors; privacy and trust between HEIs and students.

关键词： Blockchain Higher education institution (HEI) Administration Protocol level Application level Application

A CFD Model to Evaluate Near-Surface Oil Spill from a Broken Loading Pipe in Shallow Coastal Waters

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Fluid Dynamics & Materials Processing 2024年第1期20卷 59-77页

作者： Portia felix Lee Leon Derek Gay Stefano Salon Hazi Azamathulla Department of Civil and Environmental Engineering The University of the West IndiesSt.AugustineTrinidad and Tobago National Institute of Oceanography and Experimental Geophysics-OGS TriesteItaly

Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social *** is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located *** study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water *** results show that the spill overall profile is articulated in three major flow *** first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill *** behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the *** Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.

关键词： CFD model Navier-Stokes equations projection method water surface oil spill shallow coastal waters

Exploring the size of Andean condor foraging groups along an altitudinal and latitudinal gradient in the Tropical Andes: Ecological and conservation implications

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Current Zoology 2024年第2期70卷 225-232页

作者： Diego Mendez felix Hernan Vargas JoséHernan Sarasola Pedro P.Oleaa Departamento de Ecologia Universidad Autonoma de MadridCalle Darwin 228049MadridSpain Museo Nacional de Historia Natural Calle 26 s/nCota CotaLa PazBolivia The Peregrine Fund 5668 West Flying Hawk LaneBoiseID 83709USA Centro para el Estudio y Conservacion de Aves Rapaces en Argentina(CECARA) Universidad Nacional de La PampaAvda Uruguay 1516300 Santa RosaLa PampaArgentina Instituto de las Ciencias Ambientales y de la Tierra de La Pampa(INCITAP-CONICET) Avda.Uruguay 1516300 Santa RosaLa PampaArgentina Centro de Investigacion en Biodiversidad y Cambio Global(CIBC-UAM) Universidad Autonoma de MadridMadridCalle Darwin 228049Madrid Snain

Patterns of variation in the size of vulture foraging groups,and their ecological causes and consequences,remain litle explored despite strong links with the carrion recycling service that this key functional group *** documented the group size-frequency pattern of Andean con-dors Vultur gryphus gathered to feed on 42 equine carcasses experimentally placed in Bolivia,between 2012 and 2019,along an elevation range of 1,300-4,500 m *** on the location(altitude and latitude)of the foraging groups,we examined the relationship between their size and species'population parameters(size and trend),habitat conditions,and livestock carcass availability and *** utilized a high frequency(93%)of carcasses forming groups that ranged from 1 to 80 individuals(mean=25,median=18)and shaped a"lazy-J curve"typical pattern of size-frequency distribution whereby few groups(5,12%)were large(>55 individuals)and most(21,50%)were relatively small(<19 individuals).Group size related to altitude in that most larger groups formed at lower sites(below c.3,000 m asl),likely following an altitudinal gradient whereby larger groups are more likely to form around larger carcasses(i.e.,cattle),which are more likely to occur at lower *** of population size,group size could be an adaptive response of condors via local enhancement for improving individual scavenging *** information gaps on this topic still exist,thus we provide a set of questions to address them,especially amidst the unrestricted impacts of human activities that condition vulture survival globally.

关键词： condor andino fusion-fission dynamics group size scavenger social foraging vultures.