Liquid Research Articles

Tunable Non-Fermi Liquid Phase from Coupling to Two-Level Systems.

We study a controlled large-N theory of electrons coupled to dynamical two-level systems (TLSs) via spatially random interactions. Such a physical situation arises when electrons scatter off low-energy excitations in a metallic glass, such as a charge or stripe glass. Our theory is governed by a non-Gaussian saddle point, which maps to the celebrated spin-boson model. By tuning the coupling strength we find that the model crosses over from a Fermi liquid at weak coupling to an extended region of non-Fermi liquid behavior at strong coupling, and realizes a marginal Fermi liquid at the crossover. Our results are valid for generic space dimensions d>1.

Transient Liquid Phase Bonding with Sn-Ag-Co Composite Solder for High-Temperature Applications

In this study, a novel composite solder, Sn-3.5Ag-10.0Co, was tailored for transient liquid phase (TLP) bonding in electric vehicle power module integration. Employing a meticulous two-step joining process, the solder joint was transformed into a robust microstructure characterized by two high-melting point intermetallic compounds, Ni3Sn4 and (Co,Ni)Sn2. After 1 h of TLP bonding, the Sn-3.5Ag-10.0Co paste transformed into the IMCs, but voids persisted between them, particularly between (Co,Ni)Sn2 and Ni3Sn4. Voids significantly reduced after 2 h of bonding, with full coalescence of the joint microstructure observed. The joint continued to be densified after 3 h of TLP bonding, but voids tended to accumulate at the joint center. Failure analysis revealed crack propagation through Ni3Sn4/(Co,Ni)Sn2 interfaces and internal voids. The engineered Sn-Ag-Co TLP joint exhibited superior shear strength retention even at an elevated temperature of 200 °C, contrasting with the significant reduction observed in the Sn-3.5Ag control specimen due to remaining Sn.

Liquid phase oxidation of cyclopentanone over metal-free carbon catalysts

AbstractOxidation of cyclopentanone (CPO) was studied over metal-free carbon catalysts in solvent-free conditions. Norit SX plus (900 m2 g−1) and Vulcan XC72 (240 m2 g−1) were used as pristine materials. Catalysts were prepared by activation in nitrogen and by treatment with urea, calcined in nitrogen at 500 °C and 950 °C. SEM, EDX, XPS, X-ray powder diffraction, nitrogen adsorption–desorption isotherms, acid–base titration, FTIR and Raman techniques were used for characterization. Catalytic tests carried out at 0.45 MPa and 80–110 °C enabled to find the best results: 30% selectivity to glutaric acid (GA) and 3% to succinic acid at 25% conversion of CPO, over Vulcan type catalysts. A low activity, selectivity and strong deactivation of Norit type catalysts can be ascribed to a higher specific surface in a disordered arrangement providing a high concentration of unselective catalytic sites. A higher extent of side reactions can yield in higher molar mass products, which stick on the surface and block catalytic sites. Optimum amount of accessible planar domains, represented by graphene and/or graphitic plates with some disorders present in Vulcan type catalysts classified them superior to Norit catalysts. A redox reaction scheme of oxidation of CPO to GA is also proposed. Graphical abstract

High-Speed Generation of Microbubbles with Constant Cumulative Production in a Glass Capillary Microfluidic Bubble Generator.

This work reports a simple bubble generator for the high-speed generation of microbubbles with constant cumulative production. To achieve this, a gas-liquid co-flowing microfluidic device with a tiny capillary orifice as small as 5 μm is fabricated to produce monodisperse microbubbles. The diameter of the microbubbles can be adjusted precisely by tuning the input gas pressure and flow rate of the continuous liquid phase. The co-flowing structure ensures the uniformity of the generated microbubbles, and the surfactant in the liquid phase prevents coalescence of the collected microbubbles. The diameter coefficient of variation (CV) of the generated microbubbles can reach a minimum of 1.3%. Additionally, the relationship between microbubble diameter and the gas channel orifice is studied using the low Capillary number (Ca) and Weber number (We) of the liquid phase. Moreover, by maintaining a consistent gas input pressure, the CV of the cumulative microbubble volume can reach 3.6% regardless of the flow rate of the liquid phase. This method not only facilitates the generation of microbubbles with morphologic stability under variable flow conditions, but also ensures that the cumulative microbubble production over a certain period of time remains constant, which is important for the volume-dominated application of chromatographic analysis and the component analysis of natural gas.

In Situ Formed Organic Ion-Associate Liquid-Phase Microextraction without Centrifugation from Aqueous Solutions Using Thymol Blue and Estrogens

In this study, we present a method for ion-associated liquid phase (IALP) separation and concentration of analytes from an aqueous matrix into an IALP formed in situ by the charge neutralization reaction of organic cations and anions, without centrifugation. The effects of various factors on the extraction efficiency and other parameters are investigated, whereas no instrumental stirring, such as vortexing or ultrasonics, is required because the solvent (IALP) is formed in situ. The organic cation and anion used are ethylhexyloxypropylammonium and dodecyl sulfate, respectively. The developed in situ IALP microextraction method for phase separation without centrifugation is tested using the thymol blue dye and several endocrine disruptors. The tested endocrine disruptors (bisphenol A, 17β-estradiol, 17α-ethinylestradiol, and estrone) are analyzed via high-performance liquid chromatography/fluorescence detection, with respective detection limits of 0.02, 0.02, 0.02, and 0.4 μg L−1, and the corresponding enrichment factor ranging from 47 to 71. This IALP microextraction method can be used to separate and concentrate environmental water samples of different matrices. The employed IALP is fast and easy to use, enables an approximately 100-fold analyte concentration, and has a high affinity for estrogens, thus holding promise for the separation, concentration, and quantitation of diverse trace analytes.

Hydrogenation with dissolved Pt‐complexes homogenously distributed in the ionic liquid or enriched at the gas/ionic liquid interface

The use of homogeneous catalysts dissolved in ionic liquids (ILs) is an established field of research. Thin IL films containing dissolved catalyst complexes can be immobilized on solid porous supports, thereby creating a heterogenized catalyst material. Aiming at the deliberate positioning of such supported ionic liquid phase (SILP) catalyst, we carried out investigations of two very similar Pt‐complexes: depending on the ligand periphery, the first one is homogeneously dissolved in the IL while the second one strongly enriches at the gas/IL interface. To study these different locations within thick IL films of approximately 1 mm thickness, we investigated the hydrogenation of ethene in a continuous pool‐reactor setup. The two complexes dissolved in the IL [C4C1Im][PF6] showed different activity which can be attributed to their different locations. At 313 K and 0.62 MPa total pressure, the surface‐enriched complex was approximately two times more active. However, under these conditions the formation of Pt particles could be observed, with the surface‐enriched complex exhibiting a stronger tendency for particle formation compared to the one homogeneously distributed in the IL, as derived from XPS and light‐scattering measurements.

Numerical Study of Heat Transfer and Fluid Flow Characteristics of a Hydrogen Pulsating Heat Pipe with Medium Filling Ratio

Benefiting from its high thermal conductivity, simple structure, and light weight, the pulsating heat pipe (PHP) can meet the requirements for high efficiency, flexibility, and low cost in industrial heat transfer applications such as aerospace detector cooling and vehicle thermal management. Compared to a PHP working at room temperature, the mechanism of a PHP with hydrogen as the working fluid differs significantly due to the unique thermal properties of hydrogen. In this paper, a two-dimensional model of a hydrogen PHP with a filling ratio of 51% was established to study the flow characteristics and thermal performance. The volume of fluid (VOF) method was used to capture the phase distribution and interface dynamics, and the Lee model was employed to account for phase change. To validate the model, a comparison was conducted between the simulation results and experimental data obtained in our laboratory. The simulation results show that the pressure and temperature errors were within 25% and 5%, respectively. Throughout a pressure oscillation cycle, the occurrence of uniform flow velocity, acceleration, and flow reversal can be attributed to the changes in the vapor–liquid phase distribution resulting from the effect of condensation and evaporation. In addition, when the fluid velocity was greater than 0.6 m/s, dynamic contact angle hysteresis was observed in the condenser. The results contribute to a deeper understanding of the flow and heat transfer mechanism of the hydrogen PHPs, which have not been yet achieved through visualization experiments.

A Novel 3D-Printed Gravity-Independent Air-Eliminating Filter for Rapid Intravenous Infusions.

INTRODUCTION: The absence of a consistent downward G vector can make separation of gases from liquids challenging, such as in field medicine without stable upright equipment or during spaceflight. This limits the use of medical equipment and procedures like administration of intravenous (IV) fluids in microgravity and can make field medicine hazardous. Administering IV fluids and medications in microgravity requires a technique to separate air from the liquid phase. Current commercial filters for separation of gases are incompatible with high flow and blood. We present a novel filter designed to provide adequate air clearance without a consistent downward G vector.METHODS: Inline air-eliminating filters were designed for use with IV fluid tubing in microgravity using computer-aided design software and printed using nylon 12 on an EOS Selective Laser Sintering 3D printer. A 0.2-μm membrane filter was adhered around a central, hollow pillar with external spiral baffles allowing separation and venting of air from the fluid. Results were compared against commercially available inline air-eliminating filters.RESULTS: The 3D-printed filters outperformed the commercial filters in both percentage of air removed and flow rates. The centrifugal, baffled filter had flow rates that far exceeded the commercial filters during rapid transfusion.DISCUSSION: IV fluid administration is an often underappreciated and a necessary basic requirement for medical treatment. An air-eliminating filter compatible with blood and rapid transfusion was developed and validated with crystalloid solutions to allow the successful administration of IV fluid and medication without a consistent downward G vector.Formanek A, Townsend J, Ottensmeyer MP, Kamine TH. A novel 3D-printed gravity-independent air-eliminating filter for rapid intravenous infusions. Aerosp Med Hum Perform. 2024; 95(6):327-332.

Critical Experiments and Thermodynamic Modeling of the Li2O-SiO2 System

Phase equilibria studies were performed in the Li2O-SiO2 system for heat-treated samples using Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The temperature of the eutectic reaction (Liq ⇌ Li4SiO4 + Li2SiO3) was experimentally determined at 1289 K using Differential Thermal Analysis (DTA). No evidences of the Li6Si2O7 formation was found by the experimental investigation and therefore, it was not considered. Heat capacity of the Li8SiO6 phase was measured using Differential Scanning Calorimetry (DSC). Solid phases of the Li2O-SiO2 system were described as stoichiometric compounds and liquid phases by two-sublattice partially ionic liquid model. Four stoichiometric intermediate compounds were considered to be stable (Li8SiO6, Li4SiO4, Li2SiO3 and Li2Si2O5). The polymorphic transformation in Li2Si2O5 phase was accounted and the metastable liquid miscibility gap on SiO2-rich side was reproduced. The calculated phase diagram satisfactorily agrees with the experimental phase equilibria as well as calculated thermodynamic properties reproduces experimental values within uncertainty limits.

Direct evidence of gas flushing oil in deep reservoirs: Insight from integrated fluid inclusion analyses

Gas flushing of oil has been proposed as an essential process for forming some condensate gas reservoirs based on laboratory experiments and modeling but such a process has rarely been documented in subsurface reservoirs. Here, we report a unique type of yellow-ringed oil inclusions (YROIs) discovered from a deep reservoir in the Kuqa Foreland Basin, Western China that recorded the gas flushing of oil process in the subsurface. The occurrence, composition, phase state and PVT conditions of YROIs during trapping were investigated using a suite of fluid inclusion analytical methods including fluid inclusion petrography, microthermometry, fluorescence spectroscopy, PVT modeling and molecular composition analysis.YROIs found in the reservoir are three-phase (solid–liquid-vapor) fluid inclusions at room temperature with solid rings of 2–3 μm thickness and estimated volume percentages varying between 5 % and 15 %. When heated the solid ring starts to melt at around 46 °C and homogenized with the liquid phase at or above their corresponding homogenization temperatures of coeval aqueous inclusions. YROIs have fluorescence spectral peaks between 530 nm and 550 nm and an elevated spectral shoulder around 650 nm when measured at room temperature; but most spectra show a distinct “blue shift” and an absence of the 650 nm shoulder when measured at their homogenization temperatures. Some YROIs with thick yellow rings show dual spectral peaks at 570 nm and 630 nm at room temperature and their spectral peaks do not change when remeasured at their homogenization temperatures. Molecular compositions derived from synchronous fluorescence spectra and GC-MS analysis suggest that the compositions of YROIs are rich in polyaromatic compounds. PVT modeling indicates that YROIs were trapped under high pressure conditions with a pressure exceeding 50 % of the corresponding hydrostatic pressure.YROIs are interpreted to have been trapped under an elevated temperature and overpressure condition (around 110 °C and 60 MPa) relating to an intensive (wet) gas flushing of an early-charged wax-rich oil. When light hydrocarbon components in the reservoir oil were partially removed by gas, the wax/resin components rich in polyaromatic hydrocarbon compounds may precipitate due to physio-chemical fractionation. YROIs were entrapped in subsurface from a heterogeneous hydrocarbon fluid containing variable amounts of wax/resin colloids, which subsequently coalesce to form solid rings adhering to the inner wall of oil inclusions at room temperature. The presence of yellow-ringed oil inclusions in a reservoir may be indicative of a rapid gas flushing of waxy oil under high pressure, and their minimum homogenization temperature may approximate their trapping temperature.

An innovative cell-based transplantation therapy for an immature permanent tooth in an adult: a case report

BackgroundImmature teeth with necrotic pulps present multiple challenges to clinicians. In such cases, regenerative endodontic procedures (REPs) may be a favorable strategy. Cells, biomaterial scaffolds, and signaling molecules are three key elements of REPs. Autologous human dental pulp cells (hDPCs) play an important role in pulp regeneration. In addition, autologous platelet concentrates (APCs) have recently been demonstrated as effective biomaterial scaffolds in regenerative dentistry, whereas the latest generation of APCs—concentrated growth factor (CGF), especially liquid phase CGF (LPCGF)—has rarely been reported in REPs.Case presentationA 31-year-old woman presented to our clinic with the chief complaint of occlusion discomfort in the left mandibular posterior region for the past 5 years. Tooth #35 showed no pulp vitality and had a periodontal lesion, and radiographic examination revealed that the tooth exhibited extensive periapical radiolucency with an immature apex and thin dentin walls. REP was implemented via transplantation of autologous hDPCs with the aid of LPCGF. The periodontal lesion was managed with simultaneous periodontal surgery. After the treatment, the tooth was free of any clinical symptoms and showed positive results in thermal and electric pulp tests at 6- and 12-month follow-ups. At 12-month follow-up, radiographic evidence and three-dimensional models, which were reconstructed using Mimics software based on cone-beam computed tomography, synergistically confirmed bone augmentation and continued root development, indicating complete disappearance of the periapical radiolucency, slight lengthening of the root, evident thickening of the canal walls, and closure of the apex.ConclusionhDPCs combined with LPCGF represents an innovative and effective strategy for cell-based regenerative endodontics.

Highly sensitive detection of n-butanol based on In2O3/SnO2 composite hierarchical microspheres

Constructing heterojunction composites is an effective method to enhance the gas-sensing performance of metal oxide semiconductors. In this paper, In2O3 hierarchical microspheres were hydrothermally fabricated, and they were coated with SnO2 nanoparticles by a liquid phase deposition method to improve the sensor response to n-butanol. The impact of deposition time on the morphology, structure and gas sensing performance were investigated. The results indicated that the In2O3/SnO2 composite hierarchical microspheres with a deposition time of 60 min possessed the largest specific surface area of 137.6 m2/g and the best gas sensing properties. Its response toward 20 ppm n-butanol gas at 140 °C was 359, which was much higher than that of pure In2O3 hierarchical microspheres (the response was 51 to 100 ppm n-butanol gas at 140 °C). In addition to enhanced sensitivity, this sensor showed quick recovery time, excellent selectivity, repeatability, and long-term stability for n-butanol, indicating its potential for practical applications.

Diagnosis of solid–liquid phase transition using hopping particles in 2D dusty plasmas

Based on the statistical analysis of particles hopping outside the cages formed by their nearest neighboring particles, a new diagnostic of the hopping particle (HP) percentage is proposed to identify the solid–liquid phase transition in two-dimensional (2D) dusty plasmas. To demonstrate the effectiveness of the HP percentage, Langevin dynamical simulations of 2D Yukawa systems under various conditions are performed to mimic 2D dusty plasmas. It is found that the HP percentage exhibits a significant jump while decreasing the coupling parameter around the melting point, just corresponding to the solid–liquid phase transition. As compared with other traditionally used diagnostics, the HP percentage diagnostic is sensitive enough, and the dynamical information is incorporated inside. By comparing to the most widely used diagnostic of the bond-angular order parameter, the melting criterion of this HP percentage diagnostic is determined to be about 30% for the suitable time interval, which is general for the 2D Yukawa systems with different screening parameters.

Molybdenum tailings calcination for phase composition of Si-Ca-K-Mg fertilizers: Modification of phase transformation and its effects on plant growth

The high value and comprehensive utilization of molybdenum tailings for the production of fertilizer of calcium silicon magnesium potassium (Si-Ca-K-Mg fertilizer) was investigated, considering the abundant potassium feldspar (K-feldspar) content in the tailings. The effects of calcination temperatures, times, and additives (CaCO3 and CaSO4) on reaction degree, final product type, and phase transition process were studied. The results indicated that at 1200 °C, calcination time of 120 min and m(molybdenum tailings):m(CaCO3):m(CaSO4) = 1:0.7:0.2, the final product met Type I product requirements according to Chinese national standards GB/T36207-2018 as well as extremely low heavy metal contents. In the calcination process, CaO resulted from CaCO3 absorbs the liquid phase produced during K-feldspar decomposition to form CaSiO3, facilitating the K-feldspar decomposes into KAlSiO4. Simultaneously, the Ca2+ in CaSO4 replaces undecomposed K-feldspar’s K+. Additionally, CaO reacts with Al2O3, MgO, and SiO2 to produce gehlenite (Ca2Al2SiO7) and akermanite (Ca2MgSi2O7), providing plants with Ca, Mg, and Si elements. The nutrients of the fertilizer were readily assimilated by plants, improving acidic soil without causing any harm to the soil or vegetation. This work offers new ideas for large-scale and high-value utilization of molybdenum tailings as well as addressing the shortage of soluble potassium resource in China.

Phase behavior of the carbon dioxide/toluene/poly(methyl methacrylate) ternary system

Carbon dioxide/organic polymer/solvent systems have several industrial applications, including supercritical polymerization. Various process parameters affect the phase behavior of these systems, thereby influencing the process design. Accordingly, the phase behavior of a carbon dioxide (CO2)/toluene (Tol)/poly(methyl methacrylate) (PMMA) ternary system was investigated in this study. Measurements were performed using a synthetic method combined with laser displacement and turbidity measurement. Bubble points (vapor–liquid phase separation) were determined from changes in the piston displacement, whereas cloud points (liquid–liquid (LL) phase separation) were determined from changes in the turbidity The phase boundaries of CO2 mass fractions ranging from 0.098 to 0.577 were measured by varying the Tol/PMMA ratio. The homogeneous phase area decreased when the ratio of PMMA to Tol increased, molecular weight of PMMA increased, and/or temperature decreased. These changes in the LL phase separation behavior were explained with reference to the free volume (vf) and solubility parameter (δ) estimated using the Sanchez–Lacombe equation of state. The estimation of vf and δ is expected to be helpful in comprehensively understanding the phase diagram and in predicting the phase behavior of CO2/organic solvent/polymer systems.

Spectral optical performance of phase-change-material-filled glass-block system: Experimental evaluation and comparative exploration

Research on sustainable building design is pushing boundaries to introduce innovative solutions that enhance energy efficiency and improve user comfort. The integration of phase-change materials (PCMs) into transparent façade elements has gained substantial attention; however, its widespread application in current construction practices remains limited. This study examined the solar/light transmittance of PCM-based materials embedded in transparent façade elements, focusing on providing and comparing the optical properties of modular glass blocks integrated with PCM measured experimentally in a laboratory setting. Optical properties of multi-layer and non-homogeneous systems represent a more complex problem in terms of proper characterisation. To overcome this limitation, more comprehensive approaches can be considered, including integrating spheres to perform measurements on the complex nonhomogeneous glass system. This study employed spectrophotometric measurements within the visible and near-infrared (NIR) spectra by two different measurements methods: a direct method and one using an integrating sphere. Additionally, the investigation was based on a comparison between clear and various PCM-filled glass blocks. The results demonstrated that the direct method facilitated reliable spectral transmittance measurements with deviations not exceeding 3 %. In addition, the results revealed that paraffinic PCM glass blocks in liquid phases could achieve up to 90 % of light transmission and act as a highly transparent system in the visible region compared with conventional air-based glass blocks (up to 77 %). However, in the NIR region, the spectral transmission of PCM glass blocks was reduced by half (around 46 %). Depending on the PCM type in solid phases, the visible transmission is significantly reduced, which is from 5 % to a maximum of 19 %. This study contributes to the expanding knowledge base on adaptive building systems, particularly those related to PCM integration in transparent façade components.

Amphiphilic NLC-Gel formulation loaded with Sebacoyl dinalbuphine ester and Nalbuphine for localized postoperative pain management

Opioids are powerful analgesics; however, their significant systemic adverse effects and the need for frequent administration restrict their use. Nalbuphine (NA) is a κ-agonist narcotic with limited adverse effects, but needs to be frequently administrated due to its short elimination half-life. Whereas sebacoyl dinalbuphine ester (SDE) is a NA prodrug, which can effectively prolong the analgesic effect, but lacks immediate pain relief. Therefore, in this study, a rapid and sustained local delivery formulation to introduce NA and SDE directly into surgical sites was developed. An amphiphilic nanostructured lipid carrier (NLC) poloxamer 407 (P407) gel (NLC-Gel) was developed to permit concurrent delivery of hydrophobic SDE from the NLC core and hydrophilic NA from P407, offering a dual rapid and prolonged analgesic effect. Benefiting from the thermal-sensitive characteristic of P407, the formulation can be injected in liquid phase and instantly transit into gel at wound site. NLC-Gel properties, including particle size, drug release, rheology, and stability, were assessed. In vivo evaluation using a rat spinal surgery model highlighted the effect of the formulation through pain behavior test and hematology analysis. NLC-Gels demonstrated an analgesic effect comparable with that of commercial intramuscular injected SDE formulation (IM SDE), with only 15 % of the drug dosage. The inclusion of supplemental NA in the exterior gel (PA12-Gel + NA) provided rapid drug onset owing to swift NA dispersion, addressing acute pain within hours along with prolonged analgesic effects. Our findings suggest that this amphiphilic formulation significantly enhanced postoperative pain management in terms of safety and efficacy.

Esterification and volatile compound manipulation using radiofrequency cold plasma

Esters are vital in many industries, including food; however, there are still significant opportunities to improve production efficiency, sustainability, and cost. Cold plasma was trialled as a novel tool to induce esterification. Cold plasma increased the esterification of hexanoic acid and methanol in gas and liquid phases. The use of argon significantly improved methanol-based esterification, when compared to air or nitrogen, of hexanoic acid in a mixed solution. This was attributed to interactions with the increased free hydroxyl radicals and hydrogen atoms produced by the argon-based plasma. However, air-based plasma significantly increased esterification when individually treating hexanoic acid in methanol, which indicates the potential use of different plasmas to induce esterification. Further evidence of this could be detected by analysing the intermediary compounds (from the proposed esterification pathway).

Changes in the Morphology and Antioxidant Status of European Red Deer Sperm Stored in the Epididymides and in a Liquid State.

The aim of this study was to evaluate the motility, morphology, and antioxidant status of European red deer sperm stored in a liquid state (variant I) and in the epididymides (variant II). Spermatozoa were harvested post-mortem from the cauda epididymis. Sperm samples in both variants were stored for up to six days (D6) at 5 °C. Spermatozoa were assessed for motility, viability, morphology, activity of antioxidant enzymes (superoxide dismutase, SOD; glutathione peroxidase, GPx; catalase, CAT), and lipid peroxidation (malondialdehyde, MDA, content). Sperm samples were analyzed on storage days 0, 2, 4, and 6 (D0-D6). Storage time and storage method significantly (p ≤ 0.05) influenced the examined variables. On D2, a decrease in motility and acrosomal integrity was observed in both storage variants, whereas a decrease in viability and an increase in MDA content were noted in spermatozoa stored in the epididymides. On D4, higher values of SOD and GPx activity and MDA content were noted in variant I than in variant II. Catalase activity was very low. GPx is the key enzyme that participates in the reduction of hydrogen peroxide in sperm cells. Spermatozoa stored in a liquid state were characterized by higher motility and viability, improved morphology and antioxidant status than those stored in the epididymides; therefore, liquid storage is more recommended for short-term preservation of epididymal spermatozoa.

Технология изготовления образцов из композитных материалов для проведения лабораторных испытаний

Based on the accumulated experience of the staff of the Institute of Marine Technologies, Energy and Transport of the Astrakhan State Technical University, the development of the production of various parts of ship hulls, elements of main and auxiliary power plants, including various fasteners and stanchions, using additive technology and other methods of forming composite materials has begun. During the implementation of the developed direction, issues arise of reducing the cost, weight of manufactured parts and improving the characteristics of sound absorption, sound insulation, vibration isolation, etc. Despite the fact that adhesives based on epoxy or polyester resin, according to technical documentation, are fast-curing adhesives, they are not applicable for the production of products using three-dimensional printing technologies. for several reasons. The factors preventing the use of materials for the production of such parts are listed: the minimum curing time of one layer of glue under optimal conditions is from one and a half hours or more, which significantly increases the interlayer time interval; the glue layer is not a self-supporting structure due to the fact that it is in a liquid state during the induction period; products made of this adhesive without reinforcement cannot withstand the required dynamic loads. In the process of experimental studies, a number of formulations based on polyester resin with different fillers were obtained, which have the necessary consistency to apply layers on top of the previous one without waiting for curing, and also contain the necessary amount of reinforcing material and other fillers required to solve problems related to vibration isolation and sound insulation.