Vacuum Exposure Research Articles

Silicate-lunar regolith composite: A vacuum self-hardened and comprehensively durable extraterrestrial construction material

Extraterrestrial exploration, represented by Lunar base construction, has been promoted worldwide as a multi-disciplinary, cutting-edge and strategic issue. Herein we proposed a novel extraterrestrial construction material composed of Lunar/Martian regolith simulants and only 4 wt% of silicate adhesive. This silicate-regolith composite can be directly self-hardened in vacuum within 4.5 h without any curing to achieve 29 MPa of hardening strength. Meanwhile, it shows comprehensive durability with stable microstructures and >70 % of residual strength against long-term vacuum exposure, huge temperature difference and intense γ-ray and proton radiations. Its in-situ solidification and durability originate from vacuum dehydration, where silica clusters in solution spontaneously cohere into a solid network with strong connections of silica tetrahedra and bound water. A moderate silicate modulus around 2.5 and appropriate modifications can disperse finer silica clusters to increase oligomer silica units in solution and enhance hardening strength. Compared with lunar geopolymer and other existing extraterrestrial construction materials, this vacuum self-hardening composite allows a cryogenic preparation even below −40 ℃ using diverse regolith with a wide range of compositions and sizes, proposing a facile, durable and versatile solution towards in-situ extraterrestrial constructions.

Dry cleaning of InSb surfaces by hydrogen molecule exposure in ultrahigh vacuum

Cleaning semiconductor surfaces by atomic hydrogen or hydrogen plasma has gained significant interest because such a dry-cleaning method enables to reduce consumption of chemicals and pure water, and to treat challenging surfaces of three-dimensional semiconductor nanostructures. We have studied effects of mere H2 molecule exposures on (111)B and (110) surfaces of InSb with native oxides in an ultrahigh-vacuum (UHV) chamber. Without any hydrogen cracking, exposure of native-oxide covered InSb(111)B, heated simultaneously at 350 °C, to H2 with a partial pressure of 5∙10−5 mbar decreases amount of surface oxides and carbon, according to x-ray photoelectron spectroscopy, and provides (2×2) low-energy electron diffraction (LEED) pattern. Scanning tunneling microscopy indicates that this InSb(111)B(2×2) surface contains still extra Sb. When the InSb temperature increases to 400 °C during the H2 exposure, LEED changes to (3×3) pattern, which is known to arise from a less Sb-rich surface compared to InSb(111)B(2×2). When InSb(111)B(3×3) is exposed to H2 at the lowered temperature of 300 °C, LEED changes back to (2×2), which is discussed to arise from that InSb(111)B(3×3) contains still oxygen. Experiments for InSb(110) support that the found H2 exposure effects apply to different crystal faces of InSb.

Development of mechanical properties of concrete in vacuum tunnel of vacuum-based maglev train

The vacuum-based maglev train is an emerging transportation system currently under development worldwide. While concrete is a technically viable material for constructing vacuum tunnels, its mechanical performance in this unique environment remains unclear. This paper investigates the behavior of concrete in vacuum using a large customized vacuum tube. The results show that concrete undergoes significant water loss in vacuum, resulting in impeded cement hydration and porous hydration products with a foam structure. Vacuum exposure during the early ages of concrete has negative effects on mechanical properties. However, once the cement hydration reaches a high level of maturity, further vacuum exposure has little influence. Compared with atmospheric conditions, the shrinkage of concrete in vacuum is significantly increased. These findings provide a valuable experimental database and new insights for the use of concrete in vacuum-based maglev trains.

Influence of low vacuum and high temperature condition on moisture transport and dry shrinkage of mature concrete

Low vacuum and high temperature typically promote the evaporation of moisture and exacerbate concrete shrinkage cracking, which highlights the issue of volume stability for concrete materials in some engineering environments (e.g. the operational environment of ultra-high-speed train in the low-vacuum tube). To evaluate its impact on moisture transport and drying shrinkage of mature concrete, different air pressure and temperature conditions were selected and the correspondent experiments of investigating moisture loss, internal relative humidity, and drying shrinkage after exposure were conducted. And the evolution of different types of moisture, hydration degree, pore structure, and morphology of matrix was analyzed through microscopic testing methods. Experimental results present that compared to the standard drying condition, the moisture loss and drying shrinkage of concrete under low vacuum and high temperature condition increased by more than 48.5 % and 77.4 % respectively. There exists a strong correlation between moisture loss and drying shrinkage of matrix after low vacuum and high temperature exposure. Besides, compared to the sole effect of low vacuum, the coupling effect of low vacuum and high temperature has a more significant impact on the moisture transport and drying shrinkage of concrete. Among them, after prolonged exposure to low vacuum and high temperature, the internal relative humidity of matrix drops to 50 %∼60 %, and the corresponding critical aperture reduces to 1.0–1.5 nm, thereby significantly increasing the shrinkage stress of concrete. Furthermore, low vacuum and high temperature condition reduces the content of capillary water, gel water, and chemically combined water, and leads to the loss of moisture in smaller pores. In addition, for mature concrete, low vacuum and high temperature condition not only impedes cement hydration but also induces the coarsening of pore structure, resulting in an increase in the number of macropores and pores around 50 nm, which correlates highly with the evolution of drying shrinkage.

In Situ IR Spectroscopy Studies of Atomic Layer-Deposited SnO2 on Formamidinium-Based Lead Halide Perovskite.

Perovskite photovoltaics has achieved conversion efficiencies of 26.0% by optimizing the optoelectronic properties of the absorber and its interfaces with charge transport layers (CTLs). However, commonly adopted organic CTLs can lead to parasitic absorption and device instability. Therefore, metal oxides like atomic layer-deposited (ALD) SnO2 in combination with fullerene-based electron transport layers have been introduced to enhance mechanical and thermal stability. Instead, when ALD SnO2 is directly processed on the absorber, i.e., without the fullerene layer, chemical modifications of the inorganic fraction of the perovskite occur, compromising the device performance. This study focuses on the organic fraction, particularly the formamidinium cation (FA+), in a CsFAPb(I,Br)3 perovskite. By employing in situ infrared spectroscopy, we investigate the impact of ALD processing on the perovskite, such as vacuum level, temperature, and exposure to half and full ALD cycles using tetrakis(dimethylamido)-Sn(IV) (TDMA-Sn) and H2O. We observe that exposing the absorber to vacuum conditions or water half-cycles has a negligible effect on the chemistry of the perovskite. However, prolonged exposure at 100 °C for 90 min results in a loss of 0.7% of the total formamidinium-related vibrational features compared to the pristine perovskite. Supported by density functional theory calculations, we speculate that FA+ deprotonates and that formamidine desorbs from the perovskite surface. Furthermore, the interaction between TDMA-Sn and FA+ induces more decomposition of the perovskite surface compared to vacuum, temperature, or H2O exposure. During the exposure to 10 ALD half-cycles of TDMA-Sn, 4% of the total FA+-related infrared features are lost compared to the pristine perovskite. Additionally, IR spectroscopy suggests the formation and trapping of sym-triazine, i.e., a decomposition product of FA+. These studies enable to decouple the effects occurring during direct ALD processing on the perovskite and highlight the crucial role of the Sn precursor in affecting the perovskite surface chemistry and compromising the device performance.

Rehydration Post-orientation: Investigating Field-Induced Structural Changes via Computational Rehydration

Proteins can be oriented in the gas phase using strong electric fields, which brings advantages for structure determination using X-ray free electron lasers. Both the vacuum conditions and the electric-field exposure risk damaging the protein structures. Here, we employ molecular dynamics simulations to rehydrate and relax vacuum and electric-field exposed proteins in aqueous solution, which simulates a refinement of structure models derived from oriented gas-phase proteins. We find that the impact of the strong electric fields on the protein structures is of minor importance after rehydration, compared to that of vacuum exposure and ionization in electrospraying. The structures did not fully relax back to their native structure in solution on the simulated timescales of 200 ns, but they recover several features, including native-like intra-protein contacts, which suggests that the structures remain in a state from which the fully native structure is accessible. Our findings imply that the electric fields used in native mass spectrometry are well below a destructive level, and suggest that structures inferred from X-ray diffraction from gas-phase proteins are relevant for solution and in vivo conditions, at least after in silico rehydration.

Исследование кровотока глазного дна в раннем послеоперационном периоде после фемтолазерной лентикулярной коррекции миопии по технологии CLEAR с помощью ОКТ-ангиорежима

Purpose. To evaluate state of the blood flow parameters of the macular region, the optic nerve disc, and the state of the premacular bag after the formation of the corneal lenticle during the correction of myopia using CLEAR technology. Material and methods. From December 2021 to February 2022, 25 patients (44 eyes) aged 18 to 39 years (31.88±1.15, M±m) with myopia (–4.08±0.19, M±m) and myopic astigmatism (–0.47±0.04, M±m), who underwent femtolaser lenticular vision correction using CLEAR technology. As additional examination methods, all patients underwent optical coherence tomography on the Nidek RS-3000 Advance AngioScan device (NIDEK, Japan) in order to evaluate the following parameters: vascular network density and blood flow index in the macular region of the retina and optic disc before surgery and 1 day after the CLEAR correction, as well as to determine the size of the premacular bag before surgery and 1 day later. Results. In patients after performing vision correction using CLEAR technology, there are no statistically significant changes in the vascular network density and blood flow index in the macular region of the retina and in the optic disc, as well as the size of the premacular bag 1 day after surgery. Conclusion. With femtolaser lenticular correction of myopia, a longer vacuum effect on the eye is provided at the stage of corneal lenticular formation. However, this does not affect the condition of the blood flow of the posterior segment of the eye in the first day after surgery. Key words: femtolaser correction, lenticula, myopia, vacuum exposure, vascular network density, blood flow index, macular area of the retina, Optical Nerv, premacular bag

In-situ solidification of alkali-activated lunar regolith: Insights into the chemical and physical origins

Lunar base fabrication has become a multi-disciplinary, cutting-edge and strategic research issue worldwide. Alkali-activated lunar regolith is considered as a prospective technique for in-situ lunar construction. This article comprehensively revealed the effects of activator types, environmental temperatures and high vacuum through mechanical properties and a series of micro characterizations. Under sealed curing, the solidification of alkali-activated lunar regolith simulant (AALRS) mainly originates from the geopolymerization between additive alkali and certain active minerals. Sodium hydroxide combining high environmental temperature over 64–75 °C could promote a dense matrix composed of alkali aluminosilicate hydrates and zeolites. But in vacuum the geopolymerization is only restricted on particle surfaces, and the dehydration of silicate solution dominates AALRS solidification. Thus, sodium silicate with high modulus presents superior solidifying capacity under vacuum exposure. Based on these solidification mechanisms, a modified AALRS processing method is designed and achieves an applicable balance between high material strength and strict requirements for in-situ fabrication under lunar environments compared to congeneric lunar construction materials.

Oxygen distribution in the structure of YBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-delta-=/SUB=- thin films after vacuum exposure at 300 K

We have found out that vacuum exposure of YBa2Cu3O7-delta thin epitaxial films at 300 K for 24 hours decreases oxygen content and induces changes in their crystal structure depending on the films synthesis conditions. YBa2Cu3O7-delta films on SrTiO3 (100) substrates were synthesized by pulsed laser deposition. The crystal structure was studied using XRD technique. Additional maxima of diffraction peak (005) before and after vacuum exposure indicate the presence of regions with different oxygen content; and the change in the shape of the rocking curves indicate a change in the crystallites orientation. After vacuum exposure, the oxygen deficiency delta in the films increased from ~0.01 to ~0.6 for films with a crystallites size of 2-10 nm and from ~0.25-0.35 to ~0.6 for crystallites size of 500-1000 nm. The appearance of a residual resistance after the superconducting transition in the dependence R(T) may be explained by the fact that oxygen loss mainly in the boundary regions of the crystallites takes place, so that their boundaries become dielectric, while the crystallites themselves remain superconductive. Based on the data of X-ray diffraction analysis, as well as resistive measurements, we have come to the conclusion about oxygen loss through grain boundaries in films with nanocrystallites of 2-10 nm in size, and also through structural defects in films with larger crystallites. Keywords: pulsed laser deposition, surface relief, transport characteristics of films, film evolution, SrTiO3.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ПРОЦЕССА СУШКИ ЗЕРНА ПШЕНИЦЫ ПРИ АКУСТИКО-ВАКУУМНОМ ВОЗДЕЙСТВИИ

To investigate the process of drying wheat grain under conditions of combined acousticvacuum exposure, a mathematical model of the process under consideration was developed based on differential equations. Preliminary numerical experiments were carried out using the developed mathematical model. The results of mathematical modeling were obtained in the form of dependencies of changes in mass, temperature and humidity of wheat grain both under separate acoustic and vacuum exposure, and under combined acoustic-vacuum exposure. The drying rate of wheat grain was determined, which is 0.01 g/min under acoustic exposure, 0.19 g/min under vacuum exposure and 0.28 g/min under acoustic-vacuum exposure.

Распределение кислорода в структуре тонких пленок YBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-delta-=/SUB=- после хранения в вакууме при 300 K

Abstract We have found out that vacuum exposure of YBa2Cu3O7‒δ thin epitaxial films at 300 K for 24 hours decreases oxygen content and induces changes in their crystal structure depending on the films synthesis conditions. YBa2Cu3O7‒δ films on SrTiO3 (100) substrates were synthesized by pulsed laser deposition. The crystal structure was studied using XRD technique. Additional maxima of diffraction peak (005) before and after vacuum exposure indicate the presence of regions with different oxygen content; and the change in the shape of the rocking curves indicate a change in the crystallites orientation. After vacuum exposure, the oxygen deficiency δ in the films increased from ~0.01 to 0.6 for films with a crystallites size of 2-10 nm and from ~0.25−0.35 to 0.6 for crystallites size of 500−1000 nm. The appearance of a residual resistance after the superconducting transition in the dependence R(T) may be explained by the fact that oxygen loss mainly in the boundary regions of the crystallites takes place, so that their boundaries become dielectric, while the crystallites themselves remain superconductive. Based on the data of X—ray diffraction analysis, as well as resistive measurements, we have come to the conclusion about oxygen loss through grain boundaries in films with nanocrystallites of 2-10 nm in size, and also through structural defects in films with larger crystallites.

Arc Formation on Solar Array Surfaces Under Energetic Electron Irradiation and Vacuum Exposure

The harsh space environment induces local discharges (arcs) on satellite solar panels, which can cause reduced optical transmission through solar array coverglasses, thus negatively affecting long-term satellite missions. This article presents the experimental results of low-energy (4–5 keV) electron irradiation of three common types of space solar array coverglass, CMX, CMG, and fused silica at various bias voltages. The dependence of the discharge rate on the bias voltage, coverglass composition, energy of the incident electrons, vacuum exposure, and surface conductivity was investigated. It is shown that the arc frequency is inversely related to the incident electron energy. Physicochemical models of the mechanisms occurring in different types of space array coverglasses under low-energy electron irradiation are proposed to explain the experimental findings.

Development of ionic liquid circulation system in high-vacuum chamber for semiconductor device fabrication

In this study, a high-vacuum-compatible liquid circulation system was developed using an ionic liquid with a very low vapor pressure as the working fluid. The rationale for the development of this device is the increasing need for wet processing under vacuum conditions for application to semiconductor fabrication, such as developing and rinsing. Wet processes generally use a large volume of liquid; therefore, they need to be conducted under atmospheric pressure. However, vacuum-compatible wet processes are desirable because high vacuum is beneficial for cleanliness and use of beam progression in fabrication processes. Therefore, a liquid circulation system that can be directly used under a high vacuum is needed. The system developed in this study can circulate over 100 mL ionic liquid under direct vacuum exposure, regardless of the inner chamber pressure. The usefulness of a prototype of this system was experimentally investigated. The system reached an ultra-high vacuum pressure of 10−5 Pa. Outgassed ionic liquid fragments were detected with low partial pressures of the order of <10−6 Pa. We concluded that this device can be exploited for semiconductor fabrication application.

Influence of low vacuum condition on mechanical performance and microstructure of hardened cement paste at early age

• The mechanical performance of early-age paste after low vacuum exposure is evaluated. • The influence of low vacuum on phase composition and pore structure is analyzed. • The evolution of the mechanical performance of paste is explained from the perspective of multi-scale pore structure. To explore the influence of low vacuum on the mechanical performance and microstructure of cement-based materials at early age, the mechanical properties, phase composition and multi-scale pore structure of 7d-aged hardened cement pastes exposed to low vacuum and normal air environment were studied, and the relation between mechanical performance and microstructure was analyzed. The results show that low vacuum can significantly retard the strength growth of paste at early age, and lead to the decline of strength with exposure time increasing. Moreover, the mechanical performance of cement pastes in low vacuum condition was generally weaker than that under normal air environment. Furthermore, the number of gel pores decreased, while the most probable aperture and total porosity increased after low vacuum exposure, and more micron-scale macropores and millimeter-scale defects appeared. The multi-scale variation of pore structure is the dominating reason for the delayed development and degradation of mechanical performance under low vacuum environment. In addition, the phase composition of cement pastes did not change during low vacuum exposure, and the strength of pastes was highly correlated with the total amount of some key hydration products (e.g. C-S-H gel, ettringite, calcite et al.).

Condition assessment of cable insulation materials in advanced reactor environments

While existing cable insulation materials are sufficient for use in the current reactor fleet, environmental conditions inside some advanced reactors, such as small modular reactors, will be substantially harsher. The work herein was conducted to assess the performance and overall survivability of several high-temperature, radiation resistant insulation polymers in a simulated small modular reactor environment. The materials evaluated under this research include polyether ether ketone, polyimide, and silicone rubber. These polymers were subjected to 1000 h of environmental stress exposure under two different conditions: 1) high temperature (i.e., 250 °C) in atmospheric pressure and 2) high temperature in a low-pressure vacuum (i.e., less than 2 psia). During the environmental exposure process, each insulation was periodically tested using several materials characterization techniques including Fourier transform infrared spectroscopy, oxidation induction time, and oxidation induction temperature. The objective of this testing was to assess and monitor changes that occurred in the thermal and chemical properties of the materials during the environmental exposures. The overall survivability of each insulation was assessed based on these property changes. The results of this research revealed that the polyimide and polyether ether ketone insulations had significantly better thermal and chemical stability than the silicone rubber during both the high-temperature atmospheric and vacuum exposures. Both polyimide and polyether ether ketone experienced minimal reductions in their chemical and thermal properties over the course of 1000 h in the simulated environments. Based on this research, polyimide and polyether ether ketone show promise as potential base materials for small modular reactor cable insulation.

Adhesion of lunar simulant dust to materials under simulated lunar environment conditions

A test stand was designed to semi quantitively measure the adhesion of JSC-1/1A lunar simulant dust to materials proposed for use in the lunar surface environment. Sieved simulant <45 μm in diameter was uniformly deposited on sample surfaces. Dust adhesion was indicated as the centrifugal force created from rotation of the test stand to shed dust under high vacuum and UV exposure conditions The device generated a maximum centripetal force greater than 400 g's. Dust adhesion on aluminum, anodized aluminum, Ortho fabric and Z93P painted aluminum was observed and analyzed over a 12 step, increasing acceleration profile. At each rotation cycle, dust coverage was recorded using a camera and changes in the coverage were analyzed in post-processing to provide an indication of the adhesive force dust particles would have to overcome to be removed from the surface. Results showed that all material coverage amounts exhibited a similar shedding profile with individual plateaus occurring below 30 μm depending on material. Bare and anodized aluminum had higher adhesion values in vacuum than did the samples exposed to UV at high centripetal acceleration levels. The Z93P painted aluminum and Ortho fabric indicated the opposite, whereby UV exposed samples retained more dust at higher acceleration levels and thereby larger dust particles likely adhered to the surfaces. Ultimately, this testing indicates that the apparatus provides acceptable control and conditions to assess dust adhesion of lunar simulants. Increased precision can be attained by changes in lighting, camera orientation and clarity, and sample dust application.

In-depth analysis of iodine in artificial biofilm model layers by variable excitation energy XPS and argon gas cluster ion sputtering XPS.

Here, we present a study on agarose thin-film samples that represent a model system for the exopolysaccharide matrix of biofilms. Povidone-iodide (PVP-I) was selected as an antibacterial agent to evaluate our x-ray photoelectron spectroscopy (XPS)-based methodology to trace specific marker elements, here iodine, commonly found in organic matrices of antibiotics. The in-depth distribution of iodine was determined by XPS analyses with variable excitation energies and in combination with argon gas cluster ion beam sputter cycles. On mixed agarose/PVP-I nanometer-thin films, both methods were found to solve the analytical task and deliver independently comparable results. In the mixed agarose/PVP-I thin film, we found the outermost surface layer depleted in iodine, whereas the iodine is homogeneously distributed in the depth region between this outermost surface layer and the interface between the thin film and the substrate. Depletion of iodine from the uppermost surface in the thin-film samples is assumed to be caused by ultrahigh vacuum exposure resulting in a loss of molecular iodine (I2) as reported earlier for other iodine-doped polymers.

Diabetic distal polyneuropathy: prevention, treatment and rehabilitation (review)

Relevance. Due to lifestyle changes, the prevalence of diabetes mellitus is increasing worldwide. Diabetes can affect the nervous system in various forms in the form of cognitive disorders, mono- or polyneuropathies ending in trophic disorders and "diabetic foot"; and distal symmetrical sensory-motor polyneuropathy. In the modern literature there is a significant amount of research in the field of methods of prevention, treatment and rehabilitation of patients with diabetes mellitus, accompanied by damage to the nervous system, but there is no generalized information on a comprehensive analysis of currently available techniques.The purpose of study. To study the available and most modern methods of rehabilitation of patients with diabetic damage to the nervous system with subsequent systematization of information.Materials and methods. The most relevant domestic and foreign literature sources containing information on the types of diabetic lesions of the nervous system, pathogenesis and rehabilitation of patients with these pathologies were analyzed.Results. An analysis of modern literature has shown a great variability in the prevention, treatment and rehabilitation of patients with distal diabetic polyneuropathy. Drug therapy is effective, however, with long-term use, it can be accompanied by complications from the body systems. Physiotherapeutic therapy is not inferior in variety, affecting the nervous, vascular and epithelial tissue by various methods – electric current, magnetic field, laser beams or photochromo-radiation, you can get the desired analgesic effect. The need for lifestyle is also an important part of patient therapy: maintenance of normoglycemia, smoking cessation and special physical activity.Conclusion. Treatment and rehabilitation of patients with diabetic distal painful polyneuropathy is a big problem for a neurologist-clinician. In modern sources, there is a significant variety of methods for correcting this condition, both medication and physiotherapy. Drugs as the first line of correction of somatosensory disorders are a necessary point in the treatment plan, but it is necessary to remember the side effects of any prescribed drug, the slow onset of the desired analgesic effect. This is necessary for the competent preparation of the patient for a difficult and lengthy rehabilitation process. Among the most effective drugs are gabapentin and prebagalin, drugs of the anticonvulsant group and thioctic acid. A possible bypass of side effects from drug therapy is the appointment of physical therapy, adjusting drug treatment. A significant effect, based on the presented studies, is observed when using magnetotherapy in combination with infrared radiation, transcutaneous electrical nerve stimulation and impulse current with vacuum exposure.

Novel insights into negative pressure wound healing from an in situ porcine perspective.

Negative pressure wound therapy (NPWT) is used clinically to promote tissue formation and wound closure. In this study, a porcine wound model was used to further investigate the mechanisms as to how NPWT modulates wound healing via utilization of a form of NPWT called the vacuum‐assisted closure. To observe the effect of NPWT more accurately, non‐NPWT control wounds containing GranuFoam™ dressings, without vacuum exposure, were utilized. In situ histological analysis revealed that NPWT enhanced plasma protein adsorption throughout the GranuFoam™, resulting in increased cellular colonization and tissue ingrowth. Gram staining revealed that NPWT decreased bacterial dissemination to adjacent tissue with greater bacterial localization within the GranuFoam™. Genomic analysis demonstrated the significant changes in gene expression across a number of genes between wounds treated with non‐NPWT and NPWT when compared against baseline tissue. However, minimal differences were noted between non‐NPWT and NPWT wounds, including no significant differences in expression of collagen, angiogenic, or key inflammatory genes. Similarly, significant increases in immune cell populations were observed from day 0 to day 9 for both non‐NPWT and NPWT wounds, though no differences were noted between non‐NPWT and NPWT wounds. Furthermore, histological analysis demonstrated the presence of a foreign body response (FBR), with giant cell formation and encapsulation of GranuFoam™ particles. The unique in situ histological evaluation and genomic comparison of non‐NPWT and NPWT wounds in this pilot study provided a never‐before‐shown perspective, offering novel insights into the physiological processes of NPWT and the potential role of a FBR in NPWT clinical outcomes.

Study of the kinetics of gas evolution of a polymer composite under the influence of vacuum and VUV

The paper presents data on the effect of high vacuum and vacuum ultraviolet (VUV) on a polymer composite based on polyimide track membranes. Polyimide track membranes were filled with POSS structures. For comparison, we also used pure polyimide films without filler. Exposure in high vacuum and surface treatment of the developed VUV composite were carried out in the imitation chamber of near-Earth space, located in the Space Materials Science Laboratory of BSTU named after V.G. Shukhov (Russia, Belgorod). The high resistance of the composite to high vacuum and VUV has been established. The total weight loss of the composite by 24 hours was 0.26 wt. % (after holding in vacuum) and 0.28 wt. % (after VUV).