Hanyang Li, Chen Zhao, Hao Chen, Kaiwen Wang, Ding Lan
{"title":"Fluidic Shaping and Pressure-based Precision Control of Optical Lenses","authors":"Hanyang Li, Chen Zhao, Hao Chen, Kaiwen Wang, Ding Lan","doi":"10.1007/s12217-025-10207-2","DOIUrl":"10.1007/s12217-025-10207-2","url":null,"abstract":"<div><p>Fluidic shaping of optical polymer liquids represents an innovative fabrication methodology for optical lens production, enabling rapid in-situ manufacturing of large-aperture space telescope primary mirrors. Ground-based simulation of microgravity conditions for this process can be achieved through density-matching immersion liquids. Current terrestrial fluidic shaping experiments confront significant challenges stemming from density variations during optical polymer material curing. Our study introduces a novel surface profile control technique for optical lens fabrication during density-matched fluidic solidification processes. Through precise regulation of pressure differentials across optical polymer liquid interfaces, the research resolves variable density-matching challenges inherent in polymeric optical materials and achieves convective fluid surface morphology control. A theoretical analysis model correlating surface deformation with applied pressure gradients was established, with experimental validation through comprehensive testing and computational simulations.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 6","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145296576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alex Drago-González, Ioana El Kraye Ziade, Yago Ferreiro, Ricard González-Cinca
{"title":"Heat Transfer Enhancement in Air by Means of Acoustics in Microgravity Conditions","authors":"Alex Drago-González, Ioana El Kraye Ziade, Yago Ferreiro, Ricard González-Cinca","doi":"10.1007/s12217-025-10203-6","DOIUrl":"10.1007/s12217-025-10203-6","url":null,"abstract":"<div><p>On Earth, electronic circuits dissipate heat through convective flows driven by gravity, transferring energy from devices to the environment. In microgravity, the absence of buoyancy disrupts this mechanism, causing heat accumulation and potential damage. Here, we present an experimental study on enhancing heat transfer in air in microgravity via acoustic actuation. The setup consists of a test cell and subsystems for heat generation, acoustic actuation, and data acquisition. Experiments were conducted in five drops at the ZARM Drop Tower in Bremen (Germany), each providing 9.3 seconds of microgravity. Thermocouple data and high-speed videos were recorded per drop. We analyzed temperature evolution at different positions from the heat source and heat distribution inside the test cell using the Background Oriented Schlieren technique. Qualitative and quantitative results show that acoustic actuation distributes heat over larger regions, strengthening with increased pressure amplitude. Temperature increased when actuated at resonance frequency, with heat transfer along the actuation direction increasing at a rate of 0.44 K/s. Results confirm that acoustic actuation improves heat transfer in microgravity, likely due to convection-like flows induced by acoustic streaming. This study provides a foundation for new cooling techniques applicable to satellites and spacecraft.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12217-025-10203-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karol Stasiak, Rafał Lewkowicz, Piotr Zieliński, Marek Prost
{"title":"Impact of + Gz Acceleration Stress on Accuracy of Colour-coded Number Recognition in Pilots","authors":"Karol Stasiak, Rafał Lewkowicz, Piotr Zieliński, Marek Prost","doi":"10.1007/s12217-025-10204-5","DOIUrl":"10.1007/s12217-025-10204-5","url":null,"abstract":"<div><p>Colour vision, particularly in modern so-called glass cockpits, plays a crucial role in ensuring flight safety. In this study, we investigated how exposure to high G-forces affects visual perception and performance in colour-coded number recognition tasks among pilots. Ten men fast-jet pilots (ages 28–45 years) were tested in a human centrifuge while reading digitalised plates from an Ishihara test displayed on a screen. Generated accelerations ranged from + 3 to + 7 G<sub>z</sub>, increasing in nine intervals of 0.5 G with a rapid onset rate of 1 G·s<sup>−1</sup>. During each 15-s acceleration plateau, three colour plates were displayed. Colour vision in the blue-yellow and red-green axes was tested in two separate sessions. The accuracy of predicting the correct reading of the colour plates based on the + G<sub>z</sub> level was 81% for the blue-yellow axis and 76% for the red-green axis. The first impairment in colour perception occurred at + 5.5 Gz and affected both colour axes. The reading time is slightly affected by increasing G levels, with no apparent relationship to colour processing. Sequential changes in colour perception were observed. A high sensitivity threshold of the Ishihara test likely hindered the detection of subtle changes in colour vision among pilots under high G-forces. Despite its limitations, our study provides useful insights for future research on colour vision under high-G conditions.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s12217-025-10204-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical Investigation of Motion Behavior Interference of Double Quasi-spherical Bubbles in Ultrasonic Standing Wave Fields","authors":"Hao Ni, Lu Wang, Mingjun Pang","doi":"10.1007/s12217-025-10208-1","DOIUrl":"10.1007/s12217-025-10208-1","url":null,"abstract":"<div><p>The intervention of an ultrasonic field can effectively control the kinematic behavior of bubbles, leading to an increase in the efficiency of mass and heat transfer between liquid and gas phases. Since bubbles rarely appear individually in liquid, the mechanism of multiple bubble motion affected by the ultrasonic standing wave must be thoroughly understood. The authors numerically investigated the motion process of centroid of double quasi-spherical bubbles in ultrasonic standing wave fields and the corresponding alteration of the velocity field. The effects of sound pressure amplitude, acoustic frequency and bubble radius on double quasi-spherical bubble motion were fully analyzed. It was found that the above three variables have an important effect on the double bubble motion and the surrounding flow field. When the secondary Bjerknes force is the attractive force between two bubbles, three types of motion pattern are recognized: two bubbles approaching towards each other and then coalescing into one bubble, two bubbles travelling along the same direction and then coalescing into one bubble, and two bubbles remaining in levitation respectively without coalescence. When two bubbles move together in ultrasonic standing wave fields, the appearance of the secondary Bjerknes force breaks the equilibrium relationship between the time-averaged primary Bjerknes force and buoyancy force acting on each bubble, the centroid motion of bubbles changes from levitation to rising or from rising to sinking. When two bubbles coalesce into a single bubble, its motion follows the motion law of a single bubble.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Da Jiang, Naipu Bian, Liang Wang, Dan Hua, Feng Yao
{"title":"Experimental Study on Performance Enhancement in Gradient Wick Vapor Chambers","authors":"Da Jiang, Naipu Bian, Liang Wang, Dan Hua, Feng Yao","doi":"10.1007/s12217-025-10211-6","DOIUrl":"10.1007/s12217-025-10211-6","url":null,"abstract":"<div><p>The high-efficiency vapor chamber (VC) is an effective solution for the thermal management of high-heat-flux electronic devices. To further improve the VC performance, this work proposes a gradient wick VC. A systematic experimental investigation of gradient wick VCs is conducted to evaluate their thermal performance enhancement compared to conventional wickless designs. Through comprehensive testing, the gradient wick VC demonstrates superior thermal characteristics, including 33% faster stabilization rates and significant reductions in steady-state temperature (32.5% on evaporator, 7% on condenser surfaces) under identical operating conditions. The research reveals three key operational dependencies: (1) thermal resistance increases with heat source eccentricity, though this effect diminishes at higher heat fluxes; (2) resistance grows with smaller heat source areas but stabilizes above 8 W/cm²; and (3) gravity-assisted orientation achieves up to 56% lower resistance than anti-gravity operation within 2 ~ 10 W/cm² range. The chamber reaches its heat transfer limit at 400 W (120 W/cm²), beyond which performance degrades substantially. These findings provide critical design guidelines for implementing gradient wick VCs in practical thermal management systems, particularly highlighting their improved temperature response, gravity adaptability, and area-dependent performance characteristics.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Mass Transfer Within the Lacunar-canalicular System of Rats Under Simulated Microgravity","authors":"Baochuan Xiong, Bolun Liu, Xiankang Wang, Jinduo Ye, Lilan Gao, Xuejin Li, Chunqiu Zhang","doi":"10.1007/s12217-025-10206-3","DOIUrl":"10.1007/s12217-025-10206-3","url":null,"abstract":"<div><p>Microgravity causes disuse osteoporosis in astronauts, lacking effective treatments. The mass transfer within the lacunar-canalicular system (LCS), essential for maintaining bone balance, makes studying molecular Weight solute transfer in LCS under microgravity vital for clinical solutions. In this study, a tail-suspended rat model was used to simulate microgravity on Earth. Rats were injected with fluorescent tracers of three molecular weights as the transport Mass, and the gray values of osteocytes at lacunae were detected in LCS by laser scanning confocal microscopy to represent the concentration of fluorescent tracers. Under microgravity, the gray values in lacunae farther from the Haversian canal were lower, with this trend observed in all molecular Weight fluorescent tracers. As gravity decreased, gray values in the lacunae also declined, with the most significant reductions seen in lacunae farther from the Haversian canal. For fluorescent tracers of 479 Da, 20 kDa and 150 kDa, gray values in deep lacunae decreased by 16.532%, 18.181% and 34.688%, respectively. The larger the molecular weight of the fluorescent tracers, the greater the decrease in gray values of osteocytes in all layers surrounding the Haversian canal, especially in deeper lacunae. Larger molecules face more difficulty penetrating the LCS and reaching deeper lacunae, with microgravity having a more significant effect on these molecules. Microgravity impairs mass transfer within the LCS, particularly reducing the delivery of essential components to deeper lacunae, which may lead to bone loss and induce osteoporosis. This study offers new insights for the clinical treatment of microgravity-induced osteoporosis.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Linear Stability of Marangoni Convection in a Thin Film under Vertical Vibrations","authors":"Ivan Volodin, Alexey Alabuzhev","doi":"10.1007/s12217-025-10201-8","DOIUrl":"10.1007/s12217-025-10201-8","url":null,"abstract":"<div><p>We investigate the linear stability of an incompressible, viscous liquid thin film placed on a solid substrate subjected to vertical harmonic vibrations in the presence of gravity and a negative temperature gradient. The substrate oscillates with a finite frequency, compared to the viscous time and large amplitude, compared to the film thickness. By separating the governing equations into oscillatory (fast) and time-averaged (slow) components, we obtain an analytical solution for the oscillatory fields and represent their velocity structure through isolines of stream function. Averaging over the fast time scale yields a set of amplitude equations that describe the slow evolution of the free deformable surface. The stability analysis reveals that gravity and surface tension stabilise the interface, while van der Waals attraction and the imposed thermal gradient destabilise. Vertical vibrations may stabilise the surface: at low frequencies even large amplitudes fail to suppress the long-wave instability for moderate and high Marangoni numbers, whereas at moderate to high frequencies sufficiently strong vibrations stabilise the film across the entire wavenumber spectrum. For a huge values of Marangoni number small vibrations are ineffective, but when Marangoni number is small complete stabilisation is achieved at moderate frequencies for all amplitudes considered. Results obtained in limiting cases are consistent with the previous studies for isothermal and non-vibrated cases.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mass Transfer Simulation In An Inclined Two-Layer Porous Channel By The Lattice Boltzmann Method","authors":"Ivan Volodin, Alexey Alabuzhev","doi":"10.1007/s12217-025-10200-9","DOIUrl":"10.1007/s12217-025-10200-9","url":null,"abstract":"<div><p>The study numerically investigates the mass transfer in an inclined two-layer porous channel in the gravitational field. The lower region of the channel is occupied by a porous medium, while the upper region consists of a pure fluid. The initial concentration distribution is such that the impurity is localized in the central part of the porous domain. The upper and lower walls of the channel are solid and no-flux boundary condition for the concentration is applied. Periodic boundary conditions are applied for the velocity field on the side walls, and the flow is driven by the longitudinal component of the velocity induced by the gravitational field and channel inclination. For the concentration field two boundary condition types are examined on the side walls: periodic boundary conditions, and a non-periodic characterized by a vanishing concentration at the left wall and a constant flux condition at the right wall. The problem is solved for constant porosity and permeability coefficients, with the Schmidt number fixed at <span>(varvec{Sc = 10^3 })</span>. The study focuses on the diffusion of an impurity into a viscous pure fluid for various Darcy numbers <span>(varvec{Da})</span>. The simulations are conducted using the Lattice Boltzmann Method (LBM) on a D2Q9 lattice. A modified multiple relaxation-time (MRT) LBM scheme was introduced for the mass transfer simulation in porous media. The effectiveness and applicability of the proposed scheme for such classes of problems are substantiated through the presented results. For the periodic boundary conditions, it is shown that the integral concentration within the domain is conserved, and the concentration profiles both inside and outside the porous layer converge toward the average value. In contrast, under non-periodic boundary conditions, the impurity is gradually washed out of the domain. The obtained numerical results also demonstrate that the type of boundary condition imposed on the concentration field at the side walls has a negligible effect on the velocity field. At a higher Darcy number <span>(varvec{Da = 10^{-2} })</span>, the evolution of the impurity is more pronounced, and the system reaches a steady state more rapidly. For lower Darcy numbers (<span>(varvec{ Da = 10^{-3} })</span> and <span>(varvec{Da = 10^{-4}})</span>), the impurity evolution rate outside the porous matrix is approximately the same, whereas within the porous matrix, the evolution is more intense for larger Darcy numbers.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Scaling Laws of the Drag-free Control System Between Ground Model and Space Prototype","authors":"Yuqi Ren, Chenglei Yue, Mingwei Chen, Bing Cui, Chu Zhang, Li Duan","doi":"10.1007/s12217-025-10183-7","DOIUrl":"10.1007/s12217-025-10183-7","url":null,"abstract":"<div><p>To address issues in the construction of the ground test platform and closed-loop control performance evaluation of the drag-free system in space gravitational wave detection, this paper proposes a verification method based on a ground composite semi-physical drag-free simulation system. A ground simulator for drag-free simulation is innovatively designed based on the configuration of a drag-free satellite with two test masses. The scaling laws between the space prototype and the ground simulator are determined by using the Pi theorem. The scaling laws are used as the design guide for the ground simulator. According to the principle of the drag-free satellite in the science mode, the drag-free controller is designed using the active disturbance rejection control (ADRC) algorithm, and the control scaling laws are established for the controller design of the ground simulator. The closed-loop similarity of the two systems is studied, and the simulation results indicate that the two systems exhibit similar closed-loop dynamic behavior. The drag-free controller of the space prototype can be transferred to the ground simulator for verification using control scaling laws.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. P. Lyubimova, D. V. Lyubimov, A. A. Ivanova, V. G. Kozlov, S. Meradji, B. Roux
{"title":"Mean Flows Induced by Oscillations of a Solid Body Immersed in an Isothermal Liquid","authors":"T. P. Lyubimova, D. V. Lyubimov, A. A. Ivanova, V. G. Kozlov, S. Meradji, B. Roux","doi":"10.1007/s12217-025-10197-1","DOIUrl":"10.1007/s12217-025-10197-1","url":null,"abstract":"<div><p>Mean flows induced by linear high frequency vibrations of a solid body immersed in a liquid or in contact with a free surface are studied experimentally and theoretically. It is shown that the flow structure and intensity strongly depend on a liquid viscosity and the shape of a solid body. Experiments and numerical simulations performed for the configuration imitating the Czochralski crystal growth method enabled us to emphasize the role of different vibrational mechanisms, and the role of the radius of curvature of a crystal edge (in the case of crystal immersed in the melt). Three different vibrational mechanisms of mean flow generation have been identified and emphasized.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"37 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}