Working Volume Research Articles

ВЛИЯНИЕ ИНТЕНСИВНОСТИ КРУТКИ ВОЗДУХА В ВИХРЕВЫХ ГОРЕЛКАХ НА ВЫДЕЛЕНИЕ ОКСИДОВ АЗОТА В ПРОМЫШЛЕННЫХ ТРУБЧАТЫХ ПЕЧАХ

An important task in the design and operation of industrial furnaces is to reduce the formation of harmful substances, in particular, nitrogen oxides (NOx), directly at the source of their occurrence. One of the promising methods of reducing the concentration of NOx in the gas emissions of furnaces is the use of vortex burners with a twist of the flow, providing better mixing of combustion products, thereby reducing the maximum local temperatures in the furnace and equalizing the temperatures over the working volume. However, the available information on the effect of vortex formation on the intensity of nitrogen oxides release is extremely contradictory – depending on the design of the burners and the furnace, the twist of the flow can both increase and decrease the formation of nitrogen oxides. Moreover, single burners have been studied at least in some way from the point of view of NOx release, but their interaction with each other in large-volume furnaces has not been practically investigated and requires additional study. By numerical experiments conducted on the basis of the mathematical model developed by us, it is shown that the smallest release of nitrogen oxides is ensured by the use of burners with a twist of the air flow (oxidizer), as well as their combination with two-stage combustion when the burners are located in the same horizontal plane. It is shown that the combined use of these two methods reduces the release of nitrogen oxides in the furnace by more than a factor of ten.

New seeding units for sowing winter wheat

One of the main parameters of high-quality sowing of agricultural seeds is their uniform distribution along the length, which is mainly influenced by the sowing unit. In the present work, the sowing of seeds of grain crops using a coil seeding unit is considered as an object of research. As a subject of research, the dependences of the uniformity of seed distribution along the length of the furrow on the non-uniformity of the specific working volume of the coil, the rotation frequency of the blower of the pneumatic seeder and the seeding rate are considered. The aim of the work is to improve the uniformity of the distribution of the area of nutrition that falls on each plant with an ordinary method of sowing winter wheat. The paper presents the results of theoretical prerequisites for determining the working volume of the seeding coil, the results of field experiments of the seeding unit using coils with different geometric characteristics. The analysis of the uniformity of seed distribution using regression analysis and Bayesian networks is carried out. The resulting determination coefficient of 0.82 allows concluding that the resulting mathematical model can be used for practical purposes. It is noted that the proposed cellular seeding coil stands out qualitatively among the grooved and grooved-screw coils. Its use with a probability of 80%, according to the constructed Bayesian network, at low seeding rates of 75-150 kg / ha contributes to ensuring the best indexes for the uniformity of sowing of winter wheat.

ОБҐРУНТУВАННЯ КОМПЛЕКСНИХ ЗАХОДІВ ОХОРОНИ ПРАЦІ ШАХТАРІВ ЗА ФАКТОРАМИ ЯКОСТІ РУДНИКОВОГО ПОВІТРЯ

The results of an analytical-experimental study related to the actual task of substantiating comprehensive measures for occupational safety of miners in deep coal mines on the factors of mine air quality based on the study of hydrodynamic air conditioning processes, which is especially important for the development of autonomous and energy-saving means of ensuring miners' occupational safety standards, are presented. Purpose. The goal is to substantiate and analytically study the main thermodynamic characteristics of the process of hydraulic mine air conditioning for the development of functional modules of mine air conditioners with variable indicators of rational capacities that satisfy the specific conditions of miners' workplaces in deep coal mines. Methodology. The general research methodology is based on a systematic approach to the analysis of hydraulic and thermodynamic processes, which include a complex of analytical study of the mixture of air with water droplets with substantiation and development of a mathematical model in the working volume of the air conditioner, analysis of experimental laboratory and industrial data by methods of mathematical statistics, as well as generalization regarding the determination of regularities of the main characteristics of the thermodynamic process of hydrodynamic conditioning of mine air. The results. The enthalpy and humidity indicators of the mine air have been analytically determined for the study of the energy state of the active component of the working body of the flow of a mixture of air and water droplets; diagrams of the assessment of the essence of the change in the thermodynamics of the working mixture in the hydrodynamic air conditioner have been obtained, as well as the energy characteristic of the change in the relative humidity of the air during its cooling with a change in the pressure and temperature of the working mixture in the multi-chamber ejector of the hydrodynamic air conditioner. Scientific novelty. For the first time, thermodynamic indicators of the state of the working mixture of thermopotential air and droplet water before and after conditioning, as well as indicators of changes in enthalpy, humidity and temperature of the mine air in the hydrodynamic conditioner, have been determined analytically. The practical significance of the results of the presented research is that, on the basis of energy characteristics, it becomes possible to calculate the necessary initial temperatures of water (in the range of 1.0°C-20°C) supplied to the hydrodynamic air conditioner and the initial air temperature (for limits of 30-50°C), which is a technical condition for the development of an ejector module of a hydrodynamic conditioner for a specific local working area of a deep coal mine.

The dehydrator parameters for convective drying of food products

When developing dehydration processes, special attention should be paid to the latest achievements in the field of equipment for drying agricultural products, as well as energy-saving processes used in this area. The article presents the parameters of the drying cabinet operation obtained by the authors and data on the time and efficiency of drying products of the agro-industrial complex. The material in the article may be of interest to specialists involved in drying food products, as well as to those designing and developing systems for drying. The research focuses on a RAWMID drying cabinet and samples of the extra class bananas. The research was carried out at the “Scientific and Educational Center of Refrigeration, Cryogenic Equipment, and Technology” of Kemerovo State University. The research resulted in thermograms of temperature changes in the working volume of the drying cabinet, as well identifying the temperature and mass of the dried product. The velocity field in the working volume of the dehydrator was also determined, which was found out to have a significant degree of unevenness. The results make it possible to significantly optimize the drying process, as well as to obtain a dried product of a more stable quality.

Structural solutions of the supercharged engine in the output and input system

During the intake process, the working volume of the cylinder is filled with a fresh charge. As noted, a fresh charge consists of air in a diesel engine, and in engines with ignition from an electric spark (gasoline carburetor or gasoline with fuel injection, as well as gas) – from a mixture of air and vapors of light fuel or combustible gas.

Experiments on using "prismatic" nozzle in liquid-vapor system

The article is devoted to the research of the effect of the prismatic nozzle design on the large phase contact surface while steam nozzle is used to spray the mistella in the inner cavity of the final distiller. The appearance of the dispersed phase in spraying liquid in a prismatic four-nozzle sprayer was analyzed in the experimental equipment assembled for the study of heat and matter exchange processes using prismatic nozzles. For production conditions, the effectiveness of the use of vertical prismatic nozzles has been proven to accelerate the processes of heat and substance evaporation in the working volume of the device.

Investigation of the uniformity of seed distribution during sowing of winter wheat

One of the main indicators of high-quality sowing of seeds of agricultural crops is their uniform distribution along the length, because the main influence is exerted by the sowing apparatus. In the proposed work, the sowing of seeds of grain crops using a coil seeding machine is considered as an object of research. As a subject of research, the dependences of the uniformity of the distribution of seeds along the length of the furrow on the unevenness of the specific working volume of the coil, the rotation frequency of the blower of the pneumatic seeder and the seeding rate are considered. The aim of the work is to improve the uniformity of the distribution of the area of nutrition that falls on each plant with an ordinary method of sowing winter wheat. The paper presents the results of theoretical prerequisites for determining the working volume of the seeding coil, the results of field experiments of the seeding apparatus using coils with different geometric characteristics. The analysis of the uniformity of seed distribution using regression analysis and Bayesian networks is carried out. The resulting determination coefficient of 0.82 allows us to conclude that the resulting mathematical model can be used for practical purposes. It is noted that the proposed cellular-honeycomb seeding coil stands out qualitatively among the grooved and grooved-screw.

Assessment of increased energy efficiency of vehicles with a rational reduction of engine capacity

Problem. The tendency to reduce the working volume of internal combustion engines, which has emerged in recent years in the global automotive industry, is due to the need to improve the environmental situation and energy efficiency of road transport. Goal. The aim of the study is to increase the energy efficiency of vehicles by rationally reducing the maximum effective engine capacity. Methodology. The work uses the method of partial accelerations, implemented in a mobile registration and measurement complex, which allowed the authors to obtain an improved formula for calculating the force of aerodynamic resistance. Experimental studies of car aerodynamics were also carried out. Results. The article presents the results of the authors' research, which made it possible to prove the possibility of reducing the power of the internal combustion engine while maintaining the specified maximum speed and the specified level of indicators of the dynamic properties of cars. Originality. The relationship between the degree of use of the maximum engine power and the relative change in the effective specific fuel consumption of a carburetor gasoline engine with direct injection of gasoline and diesel is determined. Practical value. Calculations performed on the example of the ZAZ-1103 "Slavuta" car showed that a rational reduction in effective power allows for a 9.5% reduction in fuel consumption, and for an engine with direct injection of gasoline and diesel engines, this leads to an increase in fuel consumption by 6.7 % and 20.3%, respectively.

Efficient Biosynthesis of (S)-1-chloro-2-heptanol Catalyzed by a Newly Isolated Fungi Curvularia hominis B-36

(S)-1-chloro-2-heptanol is an enantiopure chemical of great value that can synthesize Treprostinil for treating primary pulmonary hypertension. In this work, a new strain B-36, capable of asymmetric reduction of 1-chloro-2-heptanone to (S)-1-chloro-2-heptanol, was screened and identified as Curvularia hominis B-36 (CCTCC M 2017654) based on the morphological and internally transcribed spacer (ITS) sequence. The reductive capacity of Curvularia hominis B-36 was investigated as a whole-cell biocatalyst in the bioreduction, and the excellent yield (97.2%) and enantiomeric excess (ee) value (99.9%) were achieved under the optimal conditions as follows: 75 mM 1-chloro-2-heptanone, K2HPO4-KH2PO4 (100 mM, pH 6.0), 50 g L−1 resting cells (dry cell weight; DCW), 15% (v/v) isopropanol as co-substrate, 200 rpm, 30 °C, 20 h. The scaled-up biocatalytic process was accomplished at a bioreactor in a 1.5 L working volume, showing superb yield (~97%) and selectivity (99.9%). The product (S)-1-chloro-2-heptanol was purified and characterized by NMR. Curvularia hominis B-36 is a novel catalyst and the asymmetric synthesis route is benign and eco-friendly.

Two-stage thermophilic anaerobic digestion of cheese whey: Process optimization, comparison with single-stage, and full-scale estimation

The purpose of this study was to determine whether a single-stage or two-stage system of an anaerobic sequencing batch and fed-batch biofilm reactor (AnSBBR) would be more efficient for thermophilic whey treatment and bioenergy production. The best results were achieved at 55 °C and 15 kg-COD.m−3.d−1 with organic matter removal of 96%, methane productivity of 142.9 mol-CH4.m−3.d−1, and yield of 10.3 mol-CH4.kg-COD−1. In addition, temperature strongly impacted the microbial community diversity and had an inverse relation with the genus Methanosarcina. To treat all of the whey produced by a dairy industry, which generates 3.4 × 103 m3-whey.year−1, a single-stage anaerobic digestion system of 80.0 m³ would be required, generating a power of 75.1 kW and an energy yield of 9.89 MJ.kg-COD−1. A two-stage system designed for the same industry would have a total working volume of 134.9 m³, combining thermophilic acidogenic reactors and mesophilic methanogenic reactors, with a power of 39.1 kW and energy yield of 5.14 MJ.kg-COD−1. The single-stage system would need an investment cost of U$$ 271,681.00, which is 42% cheaper compared to the two-stage system and would be able to supply 23.5% of the energy demand required by the dairy industry.

STUDY OF MORPHOLOGICAL DIVERSITY IN SOME PLUM GENOTYPES IN THE PEDOCLIMATIC CONDITIONS OF PITEȘTI-MĂRĂCINENI

During 2020 – 2022, observations and determinations regarding the growth and fruiting at 25 plum genotypes from the Pomological Collection of RIFG Pitesti - Mărăcineni were carried out in order to identify the phenological and morphological diversity, useful to the breeding program. The variability of phenological and morphological characters has a strong genetic determinism, in correlation with the evolution of pedoclimatic conditions. In the context of climatic changes, it has been essential to understand the mechanism of interaction between the genes involved in manifesting characters and traits responsible for the adaptability and productivity of the variety and the environmental conditions. The evaluation was carried out on 100 trees (4 trees/genotype), analyzing 3,000 leaves of leaves, fruits, shoots and flowers, the working volume being over 15,000 measurements and observations. Plum is a vigorous or semi-vigorous species, but 'Centenar' and 'Zamfira' show a fairly clear difference in vigor compared to the other varieties, and this can be an advantage for these varieties when used in high-density orchards. The beginning of flowering started early in the case of two varieties ('Lama' and 'Scolduș'), medium and late for most varieties and very late for 'Grase românești', 'Vinete românești' and 'Vinete românești cl. 300', while beginning of fruit ripening occurred very early for 'Early Rivers', early in the case of 7 varieties ('Centenar', 'Tita', etc.), medium or late for 14 varieties ('Anna Spath', 'Black Diamond', 'Stanley' etc.) and very late in 'Haganta', 'Topend' and 'Renclod Violet'. Also, most of the selected CPVO descriptors were polymorphic and showed more than two phenotypes a high diversity was observed between characters regarding the flower, leaf, shoots and tree habit of the 25 studied genotypes, proving that each of them presents special characters that can be useful in future breeding programs.

Introduction of reinforcing microparticles of TiB2 and BN into aluminium by electromagnetic stirring

The paper describes an experiment in which aluminum alloy was reinforced with TiB2 and BN particles and investigates the physical properties of the resulting aluminum composite. In the experiment, TiB2 and BN reinforcing particles were introduced into molten metal as part of pellets produced from aluminum micro powder in the presence of MHD mixing with subsequent directional crystallization. The pellets were thrown into a crucible with liquid aluminum placed in the working volume of an MHD stirrer, which generated separately controlled toroidal and poloidal flows. It was found that the dissolution of the pellets prepared from the mixture of aluminum micro particles (100–150 μm) and reinforcing TiB2 micro particles (1–5 μm) under MHD stirring proceeds much better compared to the pellets with BN micro particles (1–5 μm). The pellets in which the weight percentage of BN reinforcing particles exceeds 7% poorly “dissolve” in aluminum melt, while the pellets with 10% TiB2 micro particles “dissolve” satisfactorily. Due to a large number of pellets introduced into liquid aluminum in the course of the experiment and because of the strong cooling of the melt, it was not possible to obtain the weight percentage of reinforcing micro particles in an aluminum ingot exceeding 2.5% for TiB2 micro particles and 1.4% for BN micro particles. The results of the experiment showed that the hardness and tensile strength of aluminum increase with increasing content of TiB2 and BN micro particles in a similar way, but in the case BN particles to a lesser extent. The strength and electrical resistivity of liquid aluminum reinforced with TiB2 and BN particles increase with their rising fraction.The structural study of the specimens on electron and digital optical microscopes were carried out in compliance with the state budget subject AAAAA19-119012290101-5 of the Institute of Continuum Mechanics at the UralBranch of the Russian Academy of Sciences; the experiments on introduction of microparticles into molten aluminium were funded by the Government of the Perm Kray and the Russian Foundation for Basic Research under the Ural regional project No. [19-48-590001 р_а].

ДИНАМИКА ВЗВЕШЕННОГО СЛОЯ С ПОЛИДИСПЕРСНЫМИ ЧАСТИЦАМИ В ПНЕВМОСМЕСИТЕЛЯХ НЕПРЕРЫВНОГО ДЕЙСТВИЯ

The article presents a technique that describes the dynamics of a suspended layer with polydisperse particles in the working volume of the displacement chamber of a continuous air mixer. This technique was obtained on the basis of studies conducted by the authors of the article, taking into account experimental data obtained by other scientists. This material generalizes the approach to numerical modeling of a suspended layer with particles of various dispersity (for example, for dry building mixtures) and density. The dependences of the layer boundary, its porosity and velocity parameters on particle diameters, geometrical parameters of the mixing chamber and other technological quantities affecting the suspended layer inside the chamber are established. The text of the article presents an algorithm for calculating the mechanics of a suspended layer, which has proven itself in numerical modeling of the layer with high calculation accuracy, which was later confirmed by the required amount of experimental data.

Fuel Consumption Dependence on a Share of Reduction Processes in Imperial Smelting Furnace

The paper shows the use of novel modelling techniques adapted from ironmaking in the pyrometallurgical process of zinc production. Firstly, regarding the purpose to determine the boundary conditions of reduction processes taking part in the working volume of an Imperial Smelting Furnace (ISF), a deep thermochemical analysis was conducted. On this basis and using Ramm’s principles of direct and indirect reduction optimal share, the fuel rate minimization model was built. The model’s leading role is minimizing coke consumption in the ISF while maintaining the thermal state of the furnace at the correct level. In addition, the proposed presentation of the ISF thermal state shows in a unified way all the shortcomings in the correct process operation. Verification in real conditions on the ISF in Miasteczko Śląskie shows that model implementation can bring tangible benefits. Coke savings can reach over 30 kg per tonne of raw zinc.

Characterization of Mixing by CFD Simulation and Optimization of Mixing Frequency to Break Scum and Enhance Methane Yield in Chinese Dome Digester

The Chinese dome digester (CDD) is a low-cost and the most popular anaerobic digester that is used for the treatment of organic waste such as food waste and cow dung. However, the main challenge of CDD is scum formation due to inadequate mixing intensity. This study explores computational fluid dynamics (CFD) to characterize mixing in CDD and the effects of mixing frequency (0, 4, 6, and 8 times per day) on the performance of semicontinuous anaerobic digestion to break scum and enhance methane yield. The flow field simulation on a lab-scale CDD by Ansys Fluent (v.19.2), a finite volume solver, estimated that 45% of CDD working volume was occupied by dead zones which could nurture scum. The simulation results elicited the optimization of mixing frequency. Four CDDs were operated to investigate the optimum mixing frequency. The average scum thickness for the non-mixed digester was 2 ± 0.1 cm compared to 0.2 ± 0.1, 0.8 ± 0.1, and 1.3 ± 0.2 cm for the mixed digesters (4, 6, and 8 times per day, respectively). The average methane yields for 0, 4, 6, and 8 times per day were 206 ± 191, 602 ± 87, 555 ± 59, and 492 ± 109 mL g-VS−1, respectively. Four times per day was the optimum mixing frequency and the energy required to break scum was 6.1 ± 0.3 Joules per mixing cycle. This study proves that by optimizing the mixing frequency in CDD, scum formation can be controlled without additional investment cost.

Ultrasensitive dopamine detection with graphene aptasensor multitransistor arrays

Detecting physiological levels of neurotransmitters in biological samples can advance our understanding of brain disorders and lead to improved diagnostics and therapeutics. However, neurotransmitter sensors for real-world applications must reliably detect low concentrations of target analytes from small volume working samples. Herein, a platform for robust and ultrasensitive detection of dopamine, an essential neurotransmitter that underlies several brain disorders, based on graphene multitransistor arrays (gMTAs) functionalized with a selective DNA aptamer is presented. High-yield scalable methodologies optimized at the wafer level were employed to integrate multiple graphene transistors on small-size chips (4.5 × 4.5 mm). The multiple sensor array configuration permits independent and simultaneous replicate measurements of the same sample that produce robust average data, reducing sources of measurement variability. This procedure allowed sensitive and reproducible dopamine detection in ultra-low concentrations from small volume samples across physiological buffers and high ionic strength complex biological samples. The obtained limit-of-detection was 1 aM (10–18) with dynamic detection ranges spanning 10 orders of magnitude up to 100 µM (10–8), and a 22 mV/decade peak sensitivity in artificial cerebral spinal fluid. Dopamine detection in dopamine-depleted brain homogenates spiked with dopamine was also possible with a LOD of 1 aM, overcoming sensitivity losses typically observed in ion-sensitive sensors in complex biological samples. Furthermore, we show that our gMTAs platform can detect minimal changes in dopamine concentrations in small working volume samples (2 µL) of cerebral spinal fluid samples obtained from a mouse model of Parkinson’s Disease. The platform presented in this work can lead the way to graphene-based neurotransmitter sensors suitable for real-world academic and pre-clinical pharmaceutical research as well as clinical diagnosis.

Scale-up of biomass production by Methanococcus maripaludis.

The development of a sustainable energy economy is one of the great challenges in the current times of climate crisis and growing energy demands. Industrial production of the fifth-generation biofuel methane by microorganisms has the potential to become a crucial biotechnological milestone of the post fossil fuel era. Therefore, reproducible cultivation and scale-up of methanogenic archaea (methanogens) is essential for enabling biomass generation for fundamental studies and for defining peak performance conditions for bioprocess development. This study provides a comprehensive revision of established and optimization of novel methods for the cultivation of the model organism Methanococcus maripaludis S0001. In closed batch mode, 0.05 L serum bottles cultures were gradually replaced by 0.4 L Schott bottle cultures for regular biomass generation, and the time for reaching peak optical density (OD578) values was reduced in half. In 1.5 L reactor cultures, various agitation, harvesting and transfer methods were compared resulting in a specific growth rate of 0.16 h-1 and the highest recorded OD578 of 3.4. Finally, a 300-fold scale-up from serum bottles was achieved by growing M. maripaludis for the first time in a 22 L stainless steel bioreactor with 15 L working volume. Altogether, the experimental approaches described in this study contribute to establishing methanogens as essential organisms in large-scale biotechnology applications, a crucial stage of an urgently needed industrial evolution toward sustainable biosynthesis of energy and high value products.

Scaling‐up of an Insect Cell‐based Virus Production Process in a Novel Single‐use Bioreactor with Flexible Agitation

AbstractA novel single‐use bioreactor was recently introduced to the market that is agitated by impellers suspended on flexible ropes rather than a rigid shaft. Computational fluid dynamics (CFD) models were created and validated by particle image velocimetry (PIV) to predict the bioreactor's fluid flow and mixing. The data were then used to scale‐up a Spodoptera frugiperda, subclone 9 (Sf9) insect cell‐based production of recombinant adeno‐associated virus (AAV) from a benchtop glass bioreactor to the single‐use system with 30 L working volume. This viral vector is one of the most commonly used in gene therapies. The volumetric power input was kept constant while maintaining reasonable mixing times and shear stresses between the scales. Peak cell densities of up to 7.2 × 106 cells mL−1 and maximum virus titers of 1.7 × 1011 vg mL−1 were achieved. Similar cell growth and metabolite profiles further proved the successful process transfer between the two geometrically non‐similar bioreactor systems. The pilot bioreactor yielded between 3.3 and 4.8 × 1015 vg that, depending on the therapy, can be sufficient for the treatment of a single patient.

HAPPY: Hip Arthroscopy Portal Placement Using Augmented Reality.

Correct positioning of the endoscope is crucial for successful hip arthroscopy. Only with adequate alignment can the anatomical target area be visualized and the procedure be successfully performed. Conventionally, surgeons rely on anatomical landmarks such as bone structure, and on intraoperative X-ray imaging, to correctly place the surgical trocar and insert the endoscope to gain access to the surgical site. One factor complicating the placement is deformable soft tissue, as it can obscure important anatomical landmarks. In addition, the commonly used endoscopes with an angled camera complicate hand-eye coordination and, thus, navigation to the target area. Adjusting for an incorrectly positioned endoscope prolongs surgery time, requires a further incision and increases the radiation exposure as well as the risk of infection. In this work, we propose an augmented reality system to support endoscope placement during arthroscopy. Our method comprises the augmentation of a tracked endoscope with a virtual augmented frustum to indicate the reachable working volume. This is further combined with an in situ visualization of the patient anatomy to improve perception of the target area. For this purpose, we highlight the anatomy that is visible in the endoscopic camera frustum and use an automatic colorization method to improve spatial perception. Our system was implemented and visualized on a head-mounted display. The results of our user study indicate the benefit of the proposed system compared to baseline positioning without additional support, such as an increased alignment speed, improved positioning error and reduced mental effort. The proposed approach might aid in the positioning of an angled endoscope, and may result in better access to the surgical area, reduced surgery time, less patient trauma, and less X-ray exposure during surgery.

DEVELOPING GENERAL REQUIREMENTS FOR A VARIABLE VOLUME CLIMATIC CHAMBER

Problem statement. Analysis of Ukrainian standards, harmonized with NATO standards, has shown that during tests of armaments and military equipment, including armored vehicles and motor vehicles, is due to need to conduct tests for the effects of climatic factors. One of the types of testing for climatic factors is the determination of resistance to increase temperature, decrease temperature and increase humidity. To reproduce these conditions, climatic chambers of corresponding dimensions or variable volume chambers are used. The advantage of a climatic chamber with variable volume is its flexibility, i.e. depending on the overall dimensions of the test object its working volume can be changed, which in turn significantly reduces energy consumption and the time to reach the working mode of the chamber.
 An important point when working out the general requirements for a climatic chamber of variable volume is to consider the requirements of international and national regulations in the field of defense. The most relevant are military standards that are harmonized with STANAG international military standards.
 As of today, the Armed Forces of Ukraine lack measuring and testing facilities to assess armored vehicles and automotive equipment against the above-mentioned climatic characteristics. Creation of a climatic chamber of variable volume based on the developed general requirements will make it possible to obtain quantitative values of the characteristics to be assessed during tests.
 The purpose of this article is to improve the efficiency of testing weapons and military equipment against external climatic factors by developing general requirements for a climatic chamber with variable volume.
 Conclusions. The paper proposes general requirements for a climatic chamber with variable volume, which were worked out taking into account the requirements of international and national normative documents in the field of defense. The general requirements define the composition of the chamber, its purpose, basic tasks, possibilities, conditions of application, metrological assurance. Practical implementation of the obtained results consists in the possibility of their application during the development of tender documentation for the purchase of the chamber, which will ensure an increase in the efficiency of laboratory tests of various types of weapons and military equipment on the effects of climatic factors.