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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 121 journals)
Showing 1 - 30 of 30 Journals sorted by number of followers
AIAA Journal     Hybrid Journal   (Followers: 1188)
SpaceNews     Free   (Followers: 826)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 772)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 609)
Acta Astronautica     Hybrid Journal   (Followers: 493)
Advances in Space Research     Full-text available via subscription   (Followers: 458)
Aviation Week     Full-text available via subscription   (Followers: 436)
Aerospace Science and Technology     Hybrid Journal   (Followers: 428)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 384)
Journal of Aircraft     Hybrid Journal   (Followers: 335)
Control Systems     Hybrid Journal   (Followers: 314)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 278)
Journal of Navigation     Hybrid Journal   (Followers: 277)
Gyroscopy and Navigation     Hybrid Journal   (Followers: 259)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 204)
Space Science International     Open Access   (Followers: 198)
Space Science Reviews     Hybrid Journal   (Followers: 97)
International Journal of Aerospace Engineering     Open Access   (Followers: 82)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 80)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 69)
Advances in Aerospace Engineering     Open Access   (Followers: 69)
Propulsion and Power Research     Open Access   (Followers: 68)
Aerospace     Open Access   (Followers: 60)
Space Safety Magazine     Free   (Followers: 51)
Space Research Today     Full-text available via subscription   (Followers: 48)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 46)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 40)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 39)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 37)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 34)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 34)
International Journal of Aerospace Sciences     Open Access   (Followers: 32)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 31)
Space Policy     Hybrid Journal   (Followers: 30)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 29)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 27)
Journal of Space Weather and Space Climate     Open Access   (Followers: 27)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 24)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 24)
Artificial Satellites     Open Access   (Followers: 23)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 23)
Annual of Navigation     Open Access   (Followers: 22)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 22)
Chinese Journal of Aeronautics     Open Access   (Followers: 21)
Nonlinear Dynamics     Hybrid Journal   (Followers: 20)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 19)
Aerospace Scientific Journal     Open Access   (Followers: 18)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 18)
Journal of Aerodynamics     Open Access   (Followers: 18)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 17)
Aviation     Open Access   (Followers: 17)
International Journal of Space Structures     Full-text available via subscription   (Followers: 17)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
Fatigue of Aircraft Structures     Open Access   (Followers: 15)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 12)
Aeronautical Journal, The     Hybrid Journal   (Followers: 12)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Journal of Airline and Airport Management     Open Access   (Followers: 12)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 12)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 11)
Air Force Magazine     Full-text available via subscription   (Followers: 11)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 11)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 11)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 10)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 10)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 9)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 9)
Journal of Aeronautical Materials     Open Access   (Followers: 9)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 9)
Population Space and Place     Hybrid Journal   (Followers: 9)
International Journal of Aviation Management     Hybrid Journal   (Followers: 9)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
Air Medical Journal     Hybrid Journal   (Followers: 8)
Advances in Aerospace Science and Technology     Open Access   (Followers: 8)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 7)
Journal of Aerospace Technology and Management     Open Access   (Followers: 7)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 7)
RocketSTEM     Free   (Followers: 6)
New Space     Hybrid Journal   (Followers: 6)
Aerospace Systems     Hybrid Journal   (Followers: 6)
International Journal of Turbo and Jet-Engines     Hybrid Journal   (Followers: 6)
Unmanned Systems     Hybrid Journal   (Followers: 5)
Civil Aviation High Technologies     Open Access   (Followers: 5)
Cosmic Research     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 5)
Aviation Advances & Maintenance     Open Access   (Followers: 5)
Astrodynamics     Hybrid Journal   (Followers: 4)
Life Sciences in Space Research     Hybrid Journal   (Followers: 4)
Space and Polity     Hybrid Journal   (Followers: 4)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 4)
Aerospace technic and technology     Open Access   (Followers: 3)
Investigación Pecuaria     Open Access   (Followers: 3)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
ASTRA Proceedings     Open Access   (Followers: 3)
npj Microgravity     Open Access   (Followers: 3)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
Journal of KONBiN     Open Access   (Followers: 3)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
Ciencia y Poder Aéreo     Open Access   (Followers: 2)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 2)
Microgravity Science and Technology     Hybrid Journal   (Followers: 2)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
MAD - Magazine of Aviation Development     Open Access   (Followers: 2)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 2)
Science and Education : Scientific Publication of BMSTU     Open Access   (Followers: 1)
Mekanika : Jurnal Teknik Mesin i     Open Access   (Followers: 1)
Technical Soaring     Full-text available via subscription   (Followers: 1)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 1)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 1)
Transport and Aerospace Engineering     Open Access   (Followers: 1)
Open Aerospace Engineering Journal     Open Access   (Followers: 1)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 1)
Perspectives of Earth and Space Scientists i     Open Access  

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Similar Journals
Journal Cover
Microgravity Science and Technology
Journal Prestige (SJR): 0.514
Citation Impact (citeScore): 1
Number of Followers: 2  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0938-0108 - ISSN (Online) 1875-0494
Published by Springer-Verlag Homepage  [2652 journals]
  • Analysis of the Significance of the Influence of Various Components of the
           Disturbance from a Temperature Shock on the Level of Microaccelerations in
           the Internal Environment of a Small Spacecraft
    • Abstract: The paper analyzes the influence of various disturbing components arising from a temperature shock of large elastic elements of a small spacecraft structure on the level of microaccelerations of the internal environment. The stability loss of a flat equilibrium shape of an elastic element of a small spacecraft is considered, as well as its all-round expansion when it moves from the shadow area to the illuminated part of the orbit. Conclusions are drawn about the significance of the influence of various factors in modeling the microacceleration field. The results obtained can be used in the design of small technological spacecraft.
      PubDate: 2021-03-12
       
  • Lattice Boltzmann Study on Influence of Gravitational Acceleration on Pool
           Nucleate Boiling Heat Transfer
    • Abstract: Under both normal gravity and microgravity conditions, pool boiling is an efficient mode of heat transfer which has been widely applied in practice. Studying the influence of gravitational acceleration on boiling heat transfer is not only of academic significance, but also helpful for the design of space equipment related to boiling. With the development of computer technology, numerical method has been a new reliable way to investigate the boiling heat transfer under different gravities. Pseudopotential lattice Boltzmann (i.e., LB) model is one of the most popular multiphase LB models, in which the phase interface could be formed, disappeared and migrated naturally. In this paper, the Multi-Relaxation-Time (i.e., MRT) pseudopotential LB model coupled with phase-change model was applied to simulate the pool boiling heat transfer under different gravitational accelerations and wall superheats. Pool boiling curves under different gravities were obtained. It’s found that: 1) the pool boiling heat transfer coefficient at a given wall superheat decreases with a decrease in gravity; 2) the wall superheat, as well as heat flux, at the CHF (i.e., critical heat flux) point and ONB (i.e., onset of the nucleate boiling) decrease gradually with a decrease in gravity. In addition, based on the numerical results, a new gravity scaling model was proposed to predict the influence of gravitational acceleration on the nucleate boiling heat transfer under different wall superheats. Finally, the new gravity scaling model was proved to be capable of predicting the heat flux during the nucleate boiling under different wall superheats and gravities.
      PubDate: 2021-03-05
       
  • Analysis of Circulation Reversal and Particle Transport in Evaporating
           Drops
    • Abstract: We report experimental evidence of circulation reversal in evaporating drops. The internal flow patterns and particle distribution inside the evaporating water droplet with suspended polystyrene particles was studied using the Particle Image Velocimetry (PIV) technique. Droplet placed on externally heated substrate showed two symmetric and counter rotating Marangoni convection cells at the beginning of evaporation process. Towards the final stages of evaporation, the two counter rotating Marangoni convection cells reversed the direction of circulation. Interestingly, it was observed that between these two stages four symmetric and counter rotating convection cells appeared inside the evaporating droplet. Our results are in support of recent theoretical investigations on circulation reversal in evaporating drops. The flow patterns were driven by the surface tension gradient caused by the surface temperature distribution along the droplet-air interface. The surface temperature distribution is not only dependent on the non-uniform evaporation flux but also on the conduction path from the substrate to the droplet surface. Towards the end of evaporation, the fluid flow becomes radially outward from the center to the pinned edge of the droplet. We have also investigated the evaporating droplets placed on a curved substrate. Unlike the case of flat substrate, the evaporation from curved surface resulted monotonic temperature profile. The particle distribution and resulting deposition patterns was strongly influenced by the internal fluid flow pattern and was observed to be different from that of a flat substrate.
      PubDate: 2021-02-15
       
  • Coherent Particle Structures in High-Prandtl-Number Liquid Bridges
    • Abstract: Clustering of small rigid spherical particles into particle accumulation structures (PAS) is studied numerically for a high-Prandtl-number (Pr = 68) thermocapillary liquid bridge. The one-way-coupling approach is used for calculation of the particle motion, modeling PAS as an attractor for a single particle. The attractor is created by dissipative forces acting on the particle near the boundary due to the finite size of the particle. These forces can dramatically deflect the particle trajectory from a fluid pathline and transfer it to certain tubular flow structures, called Kolmogorov–Arnold–Moser (KAM) tori, in which the particle is focused and from which it might not escape anymore. The transfer of particles can take place if a KAM torus, which is a property of the flow without particles, enters the narrow boundary layer on the flow boundaries in which the particle experiences extra forces. Since the PAS obtained in this system depends mainly on the finite particle size, it can be classified as a finite-size coherent structure (FSCS).
      PubDate: 2021-02-11
       
  • Steady-state Measurements of Ternary Mixtures in Thermogravitational
           Microcolumn Using Optical Digital Interferometry
    • Abstract: Steady-state measurements in a thermogravitational microcolumn using optical digital interferometry are presented here for the first time in the literature in the case of ternary mixtures. These measurements enabled the subsequent obtaining of thermodiffusion coefficients of a ternary mixture once convection reaches the steady-state. The ternary mixture used was the benchmark one, tetrahydronaphthalene (THN) – isobutylbenzene (IBB) and n-dodecane (nC12) with mass fraction of 0.8-0.1-0.1 respectively. Contrast factors due to the change in the concentration field were measured and compared with the corresponding ones in the literature. Uncertainty in the results was found to be of similar order of magnitude as in the case of Selectable Optical Diagnostic Instrument (SODI), which means that the condition number of that contrast factor matrix is almost equal to the present one. Final values of thermodiffusion coefficients were compared with the results reported from other optical techniques, as well as with the results obtained by the traditional long opaque thermogravitational columns (TGC). Some proposals were then made in order to improve accuracy reducing the condition number of the contrast factor matrix.
      PubDate: 2021-02-08
       
  • Research on Melt Wettability Measurements Under Microgravity
    • Abstract: Wetting and the interaction between liquid and solid phases are significantly affected by gravity. In recent years, Chinese scientists have carried out wettability experiments in space, but the limitations of experimental facilities have hindered their ability to carry out in-situ observations of the dynamic process of wettability in space. The future Chinese space station will provide a platform for real-time observation of the melt wettability in space. To study the wettability of melt under microgravity, a research method for real-time observation on orbit is proposed. The change in the image contour is determined on the basis of Hu moments, according to changes in the image, to control the acquisition frame rate. This can greatly reduce the memory required to store the images. At the same time, the proposed method uses the binarization method to process the images, and then performs target searching and positioning. Furthermore, it uses the Canny multi-level edge detection operator to extract the target contour. The Young-Laplace equation is used to fit the contour of the droplet. Finally, it obtains the surface tension and contact angle of the melt droplet in real time. The experimental results show that the data storage capacity can be reduced by 90% nearly using this method, and the change in the contact angle and surface tension in the melting process can be obtained in real time.
      PubDate: 2021-02-03
       
  • Critical Modes of Thermoelectric Convection Instabilities in a Vertical
           Slot
    • Abstract: Investigation of the natural convection in a dielectric fluid confined inside a vertical slot subject to a constant horizontal temperature gradient and a high-frequency electric field was revisited. The thermoelectric coupling produces a dielectrophoretic force which contains a term called electric buoyancy associated with an electric gravity. Similar to the Archimedean buoyancy, this force can induce thermo-electro-convective instability in a stable fluid flow. Including the feedback effect of the electric field on the flow, a three-dimensional linear stability analysis is performed to characterize the instability induced by this force. Different critical modes are found depending on the intensity of the electric field: stationary hydrodynamic modes, oscillatory thermal modes and stationary electric modes. The threshold of the electric modes is independent of the Prandtl number in contrast with the threshold of the hydrodynamic and thermal modes. The obtained results are compared with those of previous studies.
      PubDate: 2021-01-25
       
  • The Payload Development and the Experiments for Studying Thermocapillary
           Convection in TG-2 Liquid Bridge
    • Abstract: The development of space experiment payload for studying thermocapillary convection in the liquid bridge with large Pr number on TG-2 space laboratory as well as the experiments are presented in detail in this paper, and the objectives of the space experiments are confirmed. The functions of the payload are analyzed, and the technical and engineering specifications are determined. Detailed designs and experimental verifications are performed on the structure of liquid bridge columns, the method of bubble removing in the liquid, the bridge cleaning system, the accurate control of aspect ratio and volume ratio, and the high-sensitivity measurement of fluid temperature. Matching experiments on the ground according to space experiment properties are carried out, 5cSt silicone oil is selected as the fluid medium in space experiments. And the states of liquid bridge and temperature oscillation signals obtained from space experiments are presented at the end of this paper. Specific summarizations and discussions to the experiment project on fluid science in space are conducted in this paper, which will provide a useful reference for scientists participating space experimental research in the future.
      PubDate: 2021-01-23
       
  • Quantitative Evaluation of a Telerobotic System for Vascular Ultrasound
           Measurement on a Short Arm Human Centrifuge
    • Abstract: Artificial Gravity generated by Short Arm Human Centrifuges is a promising multi-system countermeasure for physiological deconditioning during long duration space flights. To allow a continuous assessment of cardiovascular hemodynamics during centrifugation, a telerobotic robotic system holding an ultrasound probe has been installed on a Short Arm Human Centrifuge. A feasibility study was conducted to define the use capabilities and limitations of such a novel method. The objective of this study is to estimate the reproducibility and precision of remotely controlled vascular ultrasound assessment under centrifugation by assessing peripheral vascular diameter and wall distension. Four repeated centrifugation runs of 5 min, with 2.4 g at feet level, were performed including a 15 min rest between each run for a group of eight healthy male volunteers. Vascular diameter and distention were assessed for the common carotid artery (CCA) and the femoral artery (FA) by ultrasound imaging using a 10 MHz linear array probe (Mylab1, Esaote). Ultrasound measurements were consecutively performed: a) by an expert user in hand-held mode in standing as well as supine position, b) using the telerobotic arm without centrifugation as baseline and c) using the telerobotic arm during centrifugation. Vascular responses were compared between baseline and under centrifugation. Inter-, intra-registration and group variability have been assessed for hand-held and remotely controlled examination. The results show that intra-registration variability, σh , was always smaller than inter-registration variability, σm, that is in turned smaller than the inter-subject variability σg (σh < σm < σg). Centrifugation caused no significant changes in CCA diameter but a lower carotid distension compared to manual and robotic ultrasound in supine position (p < 0.05). Femoral diameter was significantly decreased in hypergravity compared to robotic sonography without centrifugation. A good reproducibility and precision of the remotely controlled vascular ultrasound assessment under centrifugation could be demonstrated. In conclusion, arterial wall dynamics can be precisely assessed for the CCA and femoral artery during centrifugation using a telerobotic ultrasound measurement system. Potential improvements to further enhance reproducibility and safety of the system are discussed.
      PubDate: 2021-01-23
       
  • ESA/ELGRA Gravity-Related Research Summer School: an Introduction to
           Microgravity and Hypergravity Research for University Students
    • Abstract: The European Low Gravity Research Association (ELGRA) and the European Space Agency (ESA) co-organise since 2016 a Summer School on gravity-related research in the frame of ESA Academy’s Training and Learning Programme. This Summer School is organised every year, in June, at the ESA Education Training Centre located in ESA’s European Space Security and Education Centre (ESEC), Belgium. The Summer School explains the fundamentals of performing research at different gravity levels and offers an overview of current research activity under microgravity and hypergravity conditions in life and physical sciences. Over four and a half intensive days, up to 30 Bachelor and Master students from ESA Member States, Canada and Slovenia, attend stimulating lectures, and work within small groups to devise project ideas for prospective experiments. Gravity-related research is introduced to these future scientists and engineers by experienced professionals from across the European space and research sector. These trainers are ELGRA members and ESA experts, freely sharing their experience and know-how with the students, including their day-to-day work and research experience in biology, human physiology, physics and engineering. Each year the programme incorporates new elements to enhance the experience for the students based on their feedback. 104 university students and 43 different experts have already participated in this Summer School.
      PubDate: 2021-01-20
       
  • Thermocapillary Flow Instabilities in a Rotating Annular Pool for
           Moderate-Prandtl-number Fluid
    • Abstract: The linear stability of thermocapillary flow in a rotating annular pool at intermediate Prandtl number (Pr = 1.4) was studied over a wide range of rotation rate. The critical Marangoni number for the onset of flow instability was determined using linear stability analysis based on the spectral element method. The results indicate that the pool rotation can stabilize the thermocapillary flow and affect the instability mechanism. Specially, three bifurcations were observed with increasing Marangoni number when the rotation rate is small, and this peculiar phenomenon is believed to be the competition result of the inertial instability mechanism and the thermocapillary mechanism. Moreover, the steady axisymmetric basic flow was found to be extraordinarily stable in a certain range of rotation rate.
      PubDate: 2021-01-20
      DOI: 10.1007/s12217-020-09847-3
       
  • Characteristics of a Magnetic Bulk Thermostat for Granular Gas
           Investigations in Microgravity
    • Abstract: A 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.
      PubDate: 2021-01-18
      DOI: 10.1007/s12217-020-09853-5
       
  • Sensitivity of Plant Plasma Membrane to Simulated Microgravity
    • Abstract: Biological membranes, especially the plasma membrane, are considered to be the most sensitive to altered gravity in regard to their properties and functions. We studied the composition and content of lipids, fatty acids and sterols in the plasma membrane fractions isolated from epicotyls and roots of Pisum sativum seedlings grown during 7 days under simulated microgravity by slow clinorotation. We demonstrate differences in the content of these membrane components of clinorotated and 1 g controls. The results indicate the high sensitivity of root plasma membrane to altered gravity conditions.
      PubDate: 2021-01-14
      DOI: 10.1007/s12217-020-09865-1
       
  • Numerical Study on the Heat Transfer Characteristics of Axially Grooved
           Heat Pipe Assisted by Gravity
    • Abstract: The theoretical model of the evaporation and condensation heat transfer process of the axially grooved heat pipe (AGHP) assisted by gravity under small angle inclination is established to investigate the evaporation regimes and the heat transfer characteristics of AGHP. To reveal the heat transfer mechanism of the AGHP, the working state and gas-liquid interface distribution of the AGHP with different input power are analysed. And the influence of the inclination angle and groove structure (length-width ratio), including on the maximum heat transfer of AGHP is also discussed. The numerical simulations indicate that: With the increasing input power, the fin-film evaporation regime transits to the corner-film evaporation regime in the AGHP. The growing inclination angle enhances the gravitational effect on the liquid reflux and increases the critical input power for the evaporation regime transition. As the aspect ratio of the grooves increase, the increasing maximum radius of the meniscus leads to stronger heat transfer capacity of the AGHP.
      PubDate: 2021-01-13
      DOI: 10.1007/s12217-020-09846-4
       
  • Mechanisms of the Effect of Simulated Microgravity on the Cytotoxicity of
           NK Cells Following the DNA Methylation of NKG2D and the Expression of
           DAP10
    • Abstract: The inhibition of the cytotoxicity of NK cells by microgravity in space is of serious concern to the health of astronauts. However, there remains a lack of in-depth research into the mechanisms of action of this suppression. In the present study, the effects of simulated microgravity (SMG) on the morphology, survival rate and the ability of NK cells to kill were studied initially and then the mechanism of SMG in the inhibition of NK cytotoxicity was preliminarily investigated from the perspectives of stimulatory and inhibitory receptor expression. Further, the present study attempted to reveal the molecular mechanisms of SMG inhibition of the stimulatory receptor NKG2D from the perspective of DNA methylation and the expression of its adaptor protein DAP10. The results demonstrated that down-regulation of stimulatory receptor NKG2D expression and significantly up-regulated expression of inhibitory receptor CD158a may be important in explaining for the inhibition of NK cell cytotoxicity by SMG. The down-regulation of DAP10 expression, and not its DNA methylation, that is the possible cause of the down-regulation of NKG2D expression by SMG and the subsequent suppression of NK cell activity. However, inhibition of DAP10 expression by SMG was also not achieved by influencing methylation, and so additional analysis of the mechanism is required. The results of the present study lay the foundations for finally elucidating the molecular mechanisms by which microgravity leads to a decline in NK cell activity and contributes important evidence for interpreting the regulatory mechanisms of NK cell cytotoxicity.
      PubDate: 2021-01-07
      DOI: 10.1007/s12217-020-09863-3
       
  • Thermal Performance of an Axially Grooved Heat Pipe Subjected to Multiple
           Heating Sources
    • Abstract: An experiment of axial temperature test for a heat pipe subjected to discrete heating sources is performed for deep understanding of the thermal characteristics of axial dovetail grooved heat pipe during the unsteady and steady state. The influences of heating length, heating source position, source configurations and incline angle on the temperature profiles, heat transfer limit of the heat pipe under single heating source and multiple heating sources are examined and analyzed. As can be seen from the experiment results, the heating source shows a pivotal role in the transient characteristics of the dovetail grooved heat pipe. The heated zone of the heat pipe shows higher temperature level than that of the non-heated zone, and there is a sharp temperature variation at the transition region of the heating zone and non-heating zone. When heat is imposed at the front end of heat pipe, a dramatic increase of temperature appears soon after the heating power has reached its heat transport limitation. And this limitation can still be increased when the heating source is imposed close to the cooling section as the distance between the heating source and the cooling section decreases. Increase of heating length narrows the gap of the temperature between evaporator section and condenser section, and hence lead to lower thermal resistance, higher thermal conductivity, and superior heat transport performance. Owing to the gravity assistance on the backflow fluid in microgrooves, better thermal performance can be observed when the heat pipe works under incline state than that under horizontal state.
      PubDate: 2021-01-07
      DOI: 10.1007/s12217-020-09851-7
       
  • Steady thermocapillary droplet migration under thermal radiation with a
           uniform flux
    • Abstract: Thermocapillary migration of a droplet under thermal radiation with a uniform flux is numerically investigated and theoretically analyzed. By using the front-tracking method, it is observed that thermocapillary droplet migration at small Reynolds numbers and moderate Marangoni numbers reaches a steady process. The steady migration velocity decreases as Marangoni number increases. The time-evolution behavior of temperature fields in the steady migration process is found to be a quadratic function, in which the linear rise of the steady state temperatures with the relative time is a main characteristics. The quadratic function behavior of the temperature fields is further used to derive the steady energy equations. From the steady momentum and energy equations, an analytical result at small Reynolds number and zero Marangoni number is determined by using the method of matched asymptotic expansions. The steady migration velocity decreases as Reynolds number increases, which is in qualitatively agreement with the numerical result.
      PubDate: 2021-01-07
      DOI: 10.1007/s12217-020-09857-1
       
  • Multi-Position Calibration Method of Gyroscopes in Inertial Measurement
           Unit Based on Centrifuge with Position Platform
    • Abstract: In order to accurately calibrate the static error model coefficients of three gyroscopes simultaneously, especially the higher-order coefficients, in an inertial measurement unit, an optimal 16-position method is designed. Analysis is conducted using a precision centrifuge with a counter-rotating platform, and coordinate systems are established on centrifuge. Thus, centrifuge error sources, which may affect the calibration accuracy of a gyroscope’s drift coefficients, are analyzed, corresponding to the coordinate systems established. Precise expressions for the input angular rate and the input specific forces on each axis of the three gyroscopes are derived using a homogeneous transformation method. The influence of centrifuge error on the drift coefficients is analyzed, and the calibration accuracy can be improved by compensating for the influence of centrifuge error. The 16-position calibration method is validated through simulation, which establishes that centrifuge errors such as Δθy2t, Δθy2(−Ωt), Δθx2t, Δθx2(−Ωt), and ΔΩ mainly influences the bias MF and first-order drift coefficients MI and MS, but has little impact on higher-order coefficients. The calibration process is simple and short time-consuming, and the calibration accuracy is satisfied to requirement. After compensating for the main centrifuge errors, the 16-position method will further increase the accuracy of an inertial navigation system.
      PubDate: 2021-01-07
      DOI: 10.1007/s12217-020-09848-2
       
  • Selective Transport of Airborne Microparticles Through Micro-channels
           Under Microgravity
    • Abstract: This paper analyzes the possibility of obtaining the selective transport of microparticles suspended in air in a microgravity environment through modulated channels without net displacement of air. Using numerical simulation and bifurcation analysis tools, we show the existence of intermittent particle drift under the Stokes assumption of the fluid flow. The particle transport can be selective and the direction of transport is controlled only by the kind of pumping used. The selective transport is interpreted as a deterministic ratchet effect due to spatial variations in the flow and the particle drag. This ratchet phenomenon could be applied to the selective transport of metal particles during the short duration of microgravity experiments.
      PubDate: 2021-01-05
      DOI: 10.1007/s12217-020-09855-3
       
  • A Solute Flux Near a Solid Wall as a Reason for the Observation of
           Anomalous Transport
    • Abstract: The paper is devoted to the study of the reasons of anomalous transport observation in the experiments with microchannels. Usually, retardation of such transport is associated with the interaction of solute particles with channel walls. In the present paper, we have shown that the viscous interaction of the flow and solid wall can be the reason for the anomalous transport observation. It was illustrated on a specific example of a passive solute transport through the channel. The effect of diffusion on such transport was investigated numerically. The power law decline of concentration with respect to time was obtained in a wide range of parameters.
      PubDate: 2021-01-05
      DOI: 10.1007/s12217-020-09862-4
       
 
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