bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental effects of agricultural activity on the Crimean Peninsula
Authors: Nekrich A S
Published: June 2022

The article deals with agricultural loads occurring on the Crimean Peninsula. It was determined that distribution of agricultural lands shows a strong asymmetry in this region. At least ⅔ of the whole area is characterized by essential loads on the environment due to intensive agriculture development. Given the fact that the majority of agri-business and concentration of agricultural production can be found on territories with unfavourable natural features, it is getting obvious that the negative natural processes will rapidly accelerate and loads will increase. The study is focused on revealing the geographical distribution of environmental violations caused by agricultural activity. It is considered that variety of consequences caused by intensity of agricultural loads is strongly rooted with landscape features. It was found that the distribution of the contemporary agricultural loads reflects the ways of agrarian developed on the studied territory.
The impact of various factors on the population dynamics of Epipactis atrorubens (Hoffm. ex Bernh.) Bess. in the Middle Volga region
Authors: Fardeeva M B
Published: June 2022

Long-term population dynamics, age and spatial patterns of Epipactis atrorubens (Hoffm. ex Bernh.) Bess. are identified in the Middle Volga region in the period from 1990 to 2017. The Population dynamics were mostly of a fluctuating type, there has been a marked reduction in its number, and also a Spatial and age structure disruption due to various factors. The E. atrorubens base spectrum is centered 0.5: 8.5: 55: 36 (j:im:v:g). The dependence of E. atrorubens on temperature (r = −0.55-0.62) and positive – on precipitation and air humidity was noted, especially for pregenerative individuals (r = 0.35-0.65). Landslides and erosion caused by anthropogenic and climatic factors cause irreversible degradation of biotopes.
Spatial and temporal structure of the Acer negundo L. cenopopulation in the forest parks of Yekaterinburg
Authors: Montile A A , Tishkina E A
Published: June 2022

The article is devoted to the study of the spatio-temporal structure ofAcer negundoL. in the forest parks of Yekaterinburg on the basis of population and organism indicators. Eight fragments of ash-leaved maple cenopopulations in the Uktussky and Southwestern forest parks were examined. For the first time, a quantitative characteristic of the manifestation of organismal indicators in each ontogenetic state of maple was obtained. A feature of the spatial structure of the habitats of Acer negundo is its active introduction into cenoses in the forest parks of Ekaterinburg. An identical expansion of the species in the studied forest parks was established, however, there are also distinctive features of its habitat. In the course of the analysis of variance, the dependence of the dimensional parameters of the maple crown on changes in two factors (forest park, ontogenetic state) and their interaction was shown. The ability of the species to successfully adapt in fragmented and urbanized areas affected by recreational impacts and other forms of pollution and survive in a wide range of environmental conditions has been established.
Non-flow cryogenic supply systems for HTS power systems
Authors: Yakovlev A A , Golovanov D V
Published: June 2022

Operation principles of cryogenic supply systems for power HTS systems have been examined. Two non-flow (autonomous) cryogenic supply systems have been described. Gas circuit of cryorefrigerator uses neon, rather than helium, what makes it possible to decrease several-fold the number of compression stages in compressors and losses of working fluid in the circuit when leakage occurs. The use of turbomachines and gas bearings allows for substantially increasing an overhaul period of cryorefrigerator (over 30 000 h).
Influence of biological preservatives on the process of ensiling sorghum crops and the quality of silage
Authors: Sazonova I A , Erokhina A V , Bychkova V V
Published: June 2022

The article considers the influence of biological preservatives on the process of ensiling sorghum crops. The main indicators of silage quality at different storage periods were studied: 30, 60 and 90 days. Differences in the formation of organic acids in different batches of silage were revealed. It has been proven that biological products enhance lactic acid fermentation. Experimental batches of silage with the most optimal performance have been identified. When laying high-protein crops, the self-preservation method turned out to be ineffective.
Experimental study of heat transfer in tube-type radiator of hybrid cooling tower
Authors: Kharkov V V , Madyshev I N , Kuznetsov M G , Nikolaev A N
Published: June 2022

A hybrid cooling tower is a combined evaporative and dry cooling tower. The authors developed the hybrid cooling tower with inclined corrugated contact elements and the tube-type radiator for cooling the circulating water of industrial plants. The work aims to study heat transfer in the radiator of the cooling tower experimentally. It was found that an increase in the mass flow rate of cooled water in the radiator in the range of (6.43–37.84)10−3 kg/s leads to an increase in the ratio of the amount of heat transferred through the radiator wall to the amount of heat transferred in the evaporation part of the cooling tower by an average of 9.82 times. On the other hand, an increase in the average velocity of cooling air in the range of 1.73–4.09 m/s leads to a decrease in the proportion of heat transferred through the tube wall to the amount of heat transferred in the evaporation part of the cooling tower by an average of 1.55 times.
Using customizable simulation models of high voltage electrical circuits in educational process
Authors: Kirillov I E , Morozov I N , Cheltybashev A A
Published: June 2022

In the modern world, the issue of the use of digital technologies in the framework of teaching students in technical specialties is relevant. For a number of reasons, the solution of this issue is particularly important when preparing for training areas related to the electric power industry and high-voltage equipment. Software products that allow to carry out simulation modeling of technical systems are among the most accessible types of digital technologies used in higher educational institutions of Russia. When conducting classes on the study of transients in electrical circuits or electric drive control systems, students can use specialized software and build simulation models in the absence of real physical equipment. The paper assesses the need for training in the creation and use of simulation models of devices used in conducting high-voltage tests (using the example of a generator capable of realizing a high voltage of a given shape), as well as models of control systems of electric drives. An additional advantage contributing to the use of such schemes in teaching students is that the result of their work are the values of physical parameters presented in numerical form, which allows the developed models to be used as blocks or libraries for the implementation of larger-scale projects. A team of authors from the branch of the federal state budgetary educational institution of higher education “Murmansk Arctic State University”, Russia and the federal state autonomous educational institution of higher education “Murmansk State Technical University”, Russia process.
Formation of habitats in technogenic landscapes
Authors: Ivakina E V
Published: June 2022

The study of vegetation restoration in technogenic landscapes of Primorsky Krai of Russian Far East made it possible to identify a general algorithm for identifying succession series through an ecotopic approach. It is based on the analysis of landforms, substrate types, moisture category and vegetation cover. Using the landscape-geochemical classification, several types of ecotopes were identified: eluvial, transeluvial, transaccumulative, accumulative and subaqueous. Depending on the distribution of the selected ecotopes in different technogenic landscapes of the Primorsky Krai, the following habitats are distinguished: xeromesophytic, mesomorphic, hygromesomorphic and hydromorphic.
Improving the information content of seismic data and increasing the depth of investigation by choosing the optimal length of the amplitude adjustment operator
Authors: Akhmedov T R , Mamedova A M , Mamedov A A
Published: June 2022

The article is devoted to the role of digital automatic amplitude control in increasing the depth of seismic exploration. It is noted that the depth of productive strata is gradually increasing, at the same time, more powerful explosive sources are being replaced by relatively weak non-explosive ones. Naturally, during processing, it is necessary to pay close attention to the choice of parameters for adjusting the amplitudes. The article provides basic information about the form and amplitude of seismic vibrations, lists the main empirical formulas that characterize the dependence of the amplitudes of seismic vibrations on time. It is noted that when registering seismic vibrations, one has to deal with minimal soil displacements caused by the arrival of a seismic wave at the observation point, which must be amplified millions of times and their adjustment. In this regard, in the digital processing of seismic data, a technique was developed for recovering the true amplitudes, more precisely, the true amplitude ratio. Adjustment while maintaining the true ratio of amplitudes is used only when it is required to study the dynamics of the wave field (dynamic digital processing). The optimal choice of the length of the adjustment operator (or window) is of paramount importance, since with a small adjustment interval (less than 0.1 s), a loss of dynamic expressiveness of the recording may occur, and this is clearly shown in model studies. The article considers the efficiency of choosing the length of the optimal adjustment operator on the example of the Kurovdag area, which has complex both surface and deep seismogeological conditions. A summary of the Kurovdag field is given. An amplitude compensation function for spherical divergence is given, and to compensate for the effects associated with changes in reception and excitation conditions, a surface-matched amplitude adjustment was performed after removing amplitude bursts. A fragment of the time section is given before and after the optimal adjustment of the amplitudes according to the seismograms of the Kurovdag area, which clearly demonstrates how the information content of the time section increases and, thereby, the depth of the seismic exploration: before the optimal digital automatic adjustment of the amplitudes at times of 3.25 - 3.5 sec, no seismic horizons, while after this procedure, dynamically well-defined seismic horizons appear at the same times, reflecting the structure of the medium at great depths.
Dynamics of increasing the yield of vetch-triticale grass mixture due to the use of a new complex biofertilizer
Authors: Skamarokhova A S , Danilova A A , Agarkova N V , Babukhadia K R , Yu Arutyunova G
Published: June 2022

In the Krasnodar Territory, on the experimental field of the Krasnodar Research Centre for Animal Husbandry and Veterinary Medicine, an experiment was conducted to determine the effect of a new complex biofertilizer on the yield and biometric indicators of a vetch-triticale fodder grass mixture. The conducted experiment shows that with the use of a new complex bio-fertilizer, an increase in the density of planting is observed in triticale (by 16 pieces or by 24%) and in Glinkovskaya vetch by (15 pieces or by 30%). Empirically, it was found that it is best to cultivate vetch-triticale grass mixtures for livestock feed with varieties of Hungarian vetch, in particular with the Orlan variety, since this variety showed a greater increase in green mass both in the experimental and in the control variant. It was also found that the use of a new bio-fertilizer has a positive effect on the overall agrochemical characteristics of the soil, improving and enriching its composition.
Energy efficiency assessment of distribution networks
Authors: Zhilin E V , Yu Savvin N , Sapryka V A , Roshchubkin R P , Erofeev I A
Published: June 2022

This paper discusses the effectiveness and evaluation of the modes of distributed networks with a voltage of 33/11 kV. Using the example of a fragment of the distribution networks, the features of their construction and the main parameters are analyzed. The calculation of steady-state and post-emergency operation modes in the RastrWin software package was performed, which showed that voltage and power losses in the branches of the distribution network exceed the limit values. The classification of technical measures contributing to partial unloading of the network and increasing the capacity of power lines is given. The power values of additional sources in the form of distributed generation are taken in such a way as to compensate for the power losses in the corresponding connection nodes. An assessment of the efficiency distribution networks, taking into account the use of distributed generation, confirmed a significant reduction in voltage and capacity losses in the network branches and thereby an increase in electricity quality indicators.
Features of methane-hydrogen mixtures combustion in oxy-fuel power cycle combustion chamber
Authors: Malenkov A S , Kharlamova D M , Yu Naumov V , Karev T P
Published: June 2022

The paper is focused on the study of features of methane-hydrogen mixtures combustion in an oxy-fuel power cycle combustion chamber. The goal of the study is to find optimal combinations of thermodynamic parameters, allowing to bring the fundamental combustion characteristics, such as the normal flame propagation rate, the adiabatic combustion temperature, and the ignition delay time, closer to the parameters that are characteristic of traditional gas turbine plants. The research method includes digital experiments in the Chemkin-Pro software package using detailed kinetic patterns. The key features of the fuel combustion process in oxy-fuel power cycle combustion chambers are changing the diluent medium from atmospheric nitrogen to carbon dioxide, which is the working medium in the cycle, and applying a supercritical pressure (about 300 atm). Both changes negatively affect the combustion process intensity. To achieve the normal flame propagation rate and the maximum adiabatic temperature that are acceptable for the possible flame stabilization in the combustion zone, to exclude uneven heat release and large values of chemical underburning, the amount of CO2 diluent in the combustion zone shall be within the range of 10 to 20 % of the total amount of CO2 supplied to the combustion chamber.
The solutions of the problems of energy and transport decarbonization in Russia
Authors: Khasieva M A
Published: June 2022

The article concerns the problems of fight against Climate Change and Global Warming. Decarbonization of energy industry is necessary condition for reducing greenhouse gas emissions. Development of renewable energy sources, such as sun, wind, water (except for large hydroelectric power plants), geothermal springs, biofuels is limited by specific problems. Paris climate agreement, accepted by Russia in 2016, implies the necessity to reduce emissions by 25-30% of 1990 levels to 2030. This process is impossible without the nuclear energy development. The purpose of the article is to consider the potential of nuclear energy in solving the problems of climate change. The article is based on complex and system theoretical method and contains review and analysis of scientific conferences thesis, devoted to key-problems of nuclear energy industry in Russia and world, materials of reports of UNECE and UNSC, articles published in scientific journals. The most key advantages and disadvantages of nulear energy generation in terms of modern ecological problems are determined in the article to define the opportunities of nuclear energy integration to the system of “green” economy. The assumptions and forecasts of further development of modern energy industry are reflected in the conclusions of the article.
Study of the coolant type influence on the thermal and hydraulic characteristics of cooling channels for high-temperature turbine blades in an oxy-fuel energy system
Authors: Osipov S K , Lvov D D , Ostrovsky M A , Mechnik D A
Published: June 2022

Electricity consumption by people is increasing every year, followed by an increase in harmful emissions of carbon dioxide into the atmosphere during its generation. A promising solution to the problem of global pollution can be an oxy-fuel technology for energy production. It has been proven that the Allam cycle at an initial temperature of 1100 C is the most efficient oxy-fuel cycle. With a further increase in the initial temperature, the efficiency of this cycle decreases due to an increase in the relative coolant flow rate. This paper discusses the effect of the changeover from carbon dioxide to nitrogen coolant on thermal and hydraulic characteristics of cooling channels for the first-stage blade of a carbon dioxide turbine. We have found that, upon changeover from carbon dioxide to nitrogen cooling, the heat transfer coefficient decreases for a channel with pin intensifiers 1.3 to 1.65 times, for a channel with pin-and-dimple intensifiers, 1.65 to 1.77 times. We have also found that, upon changeover from pin intensifiers to pin-dimple ones, the heat transfer coefficient is increased for a cooling system using carbon dioxide coolant 2.2 to 2.5 times, whereas when using nitrogen coolant, the heat transfer coefficient remains unchanged. It has been also found that, to maintain a constant heat transfer coefficient upon changeover from carbon dioxide to nitrogen coolant, we should provide a 23.6% higher nitrogen flow rates compared to dioxide.
Scientific-technical analysis of the ambient temperature effect on the power of gas turbine installation in the conditions of Turkmenistan
Authors: Allakulyyev Sh , Altyyev B , Saryyev M , Hojalyyev A , Danatarova M
Published: June 2022

The rise of the ambient temperature decreases the performance of the gas turbine installations, i.e. efficiency of the GTI. To study this problem, namely, at what rate a drop of power and other parameters occurs, we decided to use the Mark VI software installed in the laboratory stand of the Department of Electric Power Stations of the State Energy Institute of Turkmenistan. In the result of the obtained data, it was concluded that at 15 °C ambient temperature, a GTI with an installed capacity of 127.1 MW will consume 7.7 kg/s of natural gas, while its energy efficiency is 36% or 100% of its nominal value, at 25 °C ambient temperature GTI consumes 7.3 kg/s of natural gas, its energy efficiency is 34.7% or 84% of its nominal value, and at 40 °C temperature GTI consumes 6.5 kg/s of natural gas, while its energy efficiency is 30% or 60% of its nominal value. Therefore, it can be stated that at elevated ambient temperatures, it is possible to forecast the performance of a GTI of all the capacities, gas consumption and power output in the conditions of Turkmenistan. If at the same time it is necessary to obtain the installed nominal capacity at elevated ambient temperatures, it becomes necessary to install additional cooling sources, where additional energy expenditures will be required, which in turn will lead to an increase in the cost of the electric energy.
The Initial stages of the reintroduction of the population of the species Dianthus acicularis Fisch. ex Ledeb. (Caryophyllaceae Juss.), endangered in the I. I. Sprygin Zhiguli State Nature Reserve
Authors: Shustov M V , Mamontov A K , Zueva M A
Published: June 2022

The experience of preserving the population of the species Dianthus acicularis Fisch. ex Ledeb. (Caryophyllaceae Juss.), which is endangered in the Zhiguli State Reserve. I. I. Sprygina. The initial stages of its reintroduction are considered, the features of the biology and ecology of the preserved natural populations are studied. Seed samples of the species were collected and multiplication under culture conditions was carried out. The resource possibilities of an artificial population for the potential reintroduction of authentic specimens of the species from the botanical garden into natural conditions were studied. A long periodicity of the formation of full-fledged seeds is shown - 1 time in 10 years, low seed productivity - about 30 seeds per individual and their low germination - 13%. The total absolute abundance over 10 years of observations has increased 4 times, has a tendency to stabilize and is not subject to changes over a number of years. The long-term dynamics of the D. acicularis abundance under the conditions of the GBS RAS is characterized by a decrease in the number of individuals of vegetative age states and an increase in the number of individuals with a generative age state, which indicates the formation of a mature population. The experience gained in creating an artificial population of D. acicularis under the conditions of the GBS RAS provides factual material on the prospects for ex situ conservation of the species and the possibilities for further creation of its reintroduced populations in the face of negative dynamics in the abundance of the species in natural conditions of the Zhiguli State Reserve. I.I. Sprygin.
The effect of biofertilizer “Bio Mix 1” on morpho-biological features of vegetable crops in greenhouse conditions
Authors: Hakobyan A H , Sargsyan G Zh , Kirakosyan G V , Martirosya G S , Tadevosyan L M
Published: June 2022

Research was carried out in the greenhouse of the Scientific Center of Vegetable-Melon and Industrial Crops in the period of 2018-2019. The effect of organic fertilizer “Bio mix 1” of Indian origin on morpho-biological features of plants, yield capacity, quality indicators of fruits and seeds of tomato, sweet pepper and cucumber has been studied. The results of the studies showed that in all studied crops “Bio mix 1” fertilizer promoted the plant growth, development and yield capacity, besides, the quality indicators of fruits and seeds were improved.
Monitoring of harmful objects of strawberry in the conditions of Central Yakutia
Authors: Belevtsova V I , Sorokopudov V N , Sorokopudova O A
Published: June 2022

This article provides monitoring of pests and diseases of strawberries in the conditions of Central Yakutia for the period since 2010. The research results were obtained on the basis of the Yakut Scientific Research Institute of Agriculture named after M.G. Safronov. The studies of harmful objects are based on standard methods for their determination. During the research since 2010, it has been established that strawberry leaf beetle, weevil, dead beetle, wireworm, slugs and leafhoppers are classified as less dangerous pests, the damage to which is not significant and depends on weather conditions. In recent years, due to the anthropogenic nature of the territories, birds of the thrush family have been identified as malicious pests of strawberries, which cause irreparable damage to the crop. For bird control, we recommend using mosquito nets, which can largely save the crop. In view of the use of strawberries for the nutrition of the population, over a long period of research (2010-2020), we have identified a biologically proven method of combating diseases and pests using timely treatments with onion peel infusion throughout the growing season, which are effective in combating pests and allows you not to use toxic chemicals, keeping strawberry plantings in an environmentally safe state. An effective way to prevent damage to strawberry leaves by spotting has been revealed - regular treatments with phytosporin. These developments in the culture of strawberries in the conditions of Yakutia make it possible to grow environmentally friendly products for the population.
Application of Callopian clay to improve the productivity of zinc-contaminated soils in lawn ecosystems
Authors: Nevedrov N P , Protsenko E P , Popova G I , Sabr Saad
Published: June 2022

Pollution of lawn soils with heavy metals leads to the suppression of life and activity of living organisms inhabiting these ecosystems. The use of various means of soil detoxification will make it possible to neutralize the effect of technogenic pressure on the functional properties of urban ecosystems. The article presents data on the sorption-fertilizing properties of Callovian clay when used in zinc-contaminated soils of lawn ecosystems. The study used a small-plot field experiment, which simulated artificial contamination of agro-gray soil with zinc. The article discusses 2 methods of tillage and 4 doses of fertilizer-sorbent. It was found that the use of Callovian clay led to an increase in the production of raw and dry phytomass of lawn grasses by 3.7 - 33.2%, microbiological activity of soils by 0.9 - 132.5 times, as well as a decrease in zinc toxicity by 10 - 25%. The sorption-fertilizing effect and the optimal doses of the applied Callovian clay were determined by the time when the Callovian clay was introduced into the soil (autumn or spring).
Liquid nitrogen removal of lunar regolith simulant from spacesuit simulants
Authors: Wells I , Bussey J , Swets N , Reising L , Butikofer C , Wallace G , Kulsa S , Leachman J
Published: June 2022

Lunar dust is a major concern for future missions to the Moon. The small size, abrasiveness, sharp morphology, toxicity, and pervasive nature of the dust can cause significant distress to both human health and equipment. Traditional spacesuit cleaning methods such as brushing and vacuuming have limited effectiveness and pose risks such as suit fabric abrasion and seal contamination. A novel mitigation method is to harness the properties of cryogenic liquids. As the liquid rapidly boils, insulated droplets form that lift and carry the dust away from the suit material, migrating toward the lowest point in an airlock for convenient collection. This publication discusses initial testing of the concept for removing lunar regolith simulant from spacesuit simulants with liquid nitrogen. A cryogen sprayer technology was adapted to investigate the effect of angle, application distance, and application time on the efficacy of dust removal. Methodology and uncertainty are presented to determine a removal percent by mass. Preliminary results show mass removal of simulated lunar dust from simulated spacesuit fabric to be greater than 90% for particles less than 10 microns. Estimated calculations are presented to demonstrate the suitability for using the concept to efficiently clean spacesuits and for the ancillary purpose of pressurizing an airlock.
Analysis of heat transfer from a local heat source at cryogenic temperatures
Authors: Johnson W L , Balasubramaniam R , Grotenrath R
Published: June 2022

Understanding the dispersion of heat around a cryogenic fluid tank, specifically the interaction between the cryogenic fluid and the tank wall is critical in the analysis of long duration cryogen storage in microgravity. The heat transfer interaction between a cryogenic storage tank and heat sources from external spacecraft structures is also one of the many factors that determine how much heat enters a tank. Recent flight experiments with two-phase fluids have indicated that local concentrations of heat input (also known as “hot spots”) can cause unwanted affects including local boiling. Computational fluid dynamic (CFD) models can provide a detailed assessment of the heat transfer occurring across a cryogenic storage system. However, CFD modeling takes time to construct and run. A simpler approach that can act as initial guidance for later CFD modeling analyzes external “hot spots” as point or finite heat sources. A radial, finite element network or a local direct solution can effectively estimate the heat spread across a cryogenic storage tank by calculating the temperature and heat load as a function of distance from the heat source. This calculation accounts for the convective heat transfer between the cryogenic fluid and storage tank surface. Similar approaches can be used to determine the effectiveness of cooling from a cryocooler as a finite, local heat sink. This approach allows for quick approximations of the thermal map across a cryogenic tank as well as sensitivity analysis under a wide range of design parameters including gravitational fields as implied through natural convection coefficients.
Integrated modular design and analysis of liquid propellant rocket engine working on liquid methane-oxygen expander cycle
Authors: Desai Rajkumar P , Kuzhiveli Biju T
Published: June 2022

Liquid Propellant Rocket Engine is still the most widely used propellant system since it provides higher thrust and specific impulse due to its higher chemical energy stored. As this technology is maturing, present developments in rocket engines demand overall design flexibility, simplicity, and reliability while preserving higher performance. Modular design is such a concept that divides a system into small modules which can individually be created and modified. This work aims to use such a concept for designing a high-performance rocket engine working on a liquid oxygen-methane expander cycle and check its feasibility. Chamber Pressure and Desired Vacuum Thrust value were taken as 3.5 MPa and 60 kN respectively. Methane is used as fuel due to its ease of availability, low manufacturing cost, and high energy density. All major components for the engine including the combustion chamber assembly, nozzle, turbopump assembly, regenerative cooling jacket, and injector were modeled. More attention was given to critical components like an injector, cooling channels with regenerative cooling analysis, and turbopump assembly. MATLAB code was developed to perform heat transfer analysis in cooling channels. The code was validated by comparing previous experiment data available from literature to check its accuracy.

A geared-shaft, axial turbine, centrifugal impeller turbopump was designed to deliver high pressure. Geometry was tested with different aspect ratio cooling channels as well as constant aspect ratio cooling channels. Cooling from variable aspect ratio channel was found superior compared to constant aspect ratio channels with less than 15% to 30% pressure drop compared to Constant aspect ratio cooling channels. Based on analysis ideal aspect ratio for maximum cooling was determined. Parametric calculations and detailed design are presented in this paper by using modular concepts and with the most favorable engine design.
Performance testing and temperature fluctuations of a 4.5 K@150 mW Joule-Thomson closed cycle cryocooler for space applications
Authors: Chen Zhichao , Liu Shaoshuai , Wu Yinong , Jiang Zhenhua , Ding Lei
Published: June 2022

To meet future space applications, the Shanghai Institute of Technology Physics, Chinese Academy of Sciences (SITP, CAS) has developed a closed cycle Joule-Thomson (JT) cryocooler with a prospect of providing more than hundred milliwatts at liquid helium temperatures. The JT cryocooler is driven by staged efficient valved linear compressors with a pressure rate of 18 (low pressure of 0.1 MPa and high pressure of about 1.8 MPa). The designed mass flow is more than 14.8 mg/s. The preliminary experiment is carried out. A two-stage precooler capable of providing a pre-cooling capacity of about 15 K is used to verify the developed JT cryocooler. The test results show that the cryocooler successfully reached 4.5 K with a cooling power of more than 150 mW. A temperature fluctuation test is carried out. A long-term temperature fluctuation of more than 12 h has been tested. There exists a strong reaction among the temperatures of 4.5 K cold head, the precooling stages, and the ambient environment. The temperature fluctuation at 4.5 K cold head is within 5 mK/10 mins because of the large temperature fluctuation of the selected pre-cooler. The quantitative analysis of the temperature fluctuation of each temperature is discussed. By substituting the pre-cooler to a two-stage pulse tube cryocooler developed in our lab, the expected temperature fluctuation can be restrained to 1 mK@10 min and 5 mK@12 h, which can meet the requirement of future applications.
Random vibration, exported vibration, and passive isolation testing of the Ricor K508N cryocooler
Authors: Anderson L , Mork J , Swenson C , Zwolinski B , Mastropietro A J , Sauder J , McKinley I , Mok M
Published: June 2022

The Ricor K508N is a rotary Stirling Cryocooler whose predecessor, the K508, has extensive flight heritage. The K508N has significant potential as a low-cost option for CubeSat infrared electro-optical payload applications. This paper will explore the work done by the ATA project on the exported vibration characterization of a set of standard K508N cryocoolers (35 atm) and the implementation and performance comparison of several passive vibration isolation and damping technologies to help mitigate the jitter effect of COTS cryocoolers. Kistler Force dynamometers and accelerometers were used to measure the K508N’s body and cold tip Multicomponent Exported Forces and Torques (EFT). Wire rope and Pyrolytic Graphite Sheet thermal straps are used as vibration isolation technologies. The K508N also underwent sine sweep resonant and peak profile testing as well as random vibration testing to GEVS launch loads in a NanoRacks soft stow configuration.
The effect of transfer line length and heat rejection temperature distribution on the Thales linear pulse tube (LPT) cryocoolers
Authors: McKinley I M , Hummel C D , Rodriguez J I
Published: June 2022

Four Thales LPT9310 and four Thales LPT9510 commercial off-the-shelf (COTS) cryocoolers were parametrically performance tested. The LPT9310 coolers had transfer lines of various lengths while the LPT9510 coolers all had the same transfer line geometry. The LPT9510 test results revealed unit-to-unit thermodynamic performance variation, quantified the effect of compressor temperature on thermodynamic performance and quantified the heat flow distribution between the compressor and expander as a function of their temperature distribution. The LPT9310 test results revealed the optimal drive frequency as a function of transfer line length, quantified the effect of heat rejection temperature distribution on thermodynamic performance and enabled the development and verification of a thermodynamic performance prediction tool that accounted for cold tip temperature, heat lift, heat rejection temperature and transfer line length.
Theoretical comparison of the thermo-mechanical fatigue characteristics of a tension rod and coil used as dewar supports
Authors: Nitin B , Singh Virdi Parmit , Sandilya Pavitra , Chakraborty Goutam
Published: June 2022

Support systems for dewars serve the dual purpose of holding the vessels together and providing a thermal insulation between the inner and the outer vessels. To decrease the heat inleak, the thermal length of the supports may be increased. The length of the support should be increased such that the support fits in the annular space between the vessels and gives the required mechanical strength. Coiled supports satisfy both the criterion. The supports experience thermal and mechanical fatigue due to the repeated filling and utilization of the cargo. This cyclic loading condition can cause mechanical fatigue failure and ductile to brittle transition of the material. While designing cryogenic dewars for long life, it is pertinent to ensure the longevity of the individual components. The life of a support depends on the number of cycles needed to cause the failure of the support. A model has been developed to predict the fatigue behaviour of support systems. Repeated loading condition was imposed to determine the life. The present work compares the fatigue characteristics of a coiled support with that of a tension rod under the same operating conditions.
Analysis of the factors influencing the precooling process of cryogenic compressed hydrogen storage tank
Authors: He M , Jia Q M , Lv C , Wu J H , Zhang Y , Zhu W P , Zhang M M , Gong L H
Published: June 2022

Cryogenic compressed hydrogen has attracted much attention recently. Its volume and weight hydrogen storage density are relatively high, which can meet the long-distance driving demand of hydrogen fuel cell vehicles. It is considered as a very promising physical storage method. In the process of transportation, the precooling process of cryogenic compressed hydrogen storage tank is very important. It is necessary to establish a reasonable mathematical model, analyse the precooling process of the storage tank theoretically, and use the hydrodynamics software for numerical simulation to analyse the influencing factors of the precooling process. On the basis of theoretical analysis, this paper uses ANSYS FLUENT software to simulate the precooling process of intake pipe length, intake pipe diameter, length diameter ratio of storage tank, insulation performance of high vacuum multilayer insulation material, lining material, initial temperature of storage tank and hydrogen filling rate. By comparing the distribution of internal temperature field and enclosure temperature field as well as precooling time, the design suggestions of Cryogenic compressed hydrogen storage tank and hydrogenation suggestions are given.
Dynamic modeling and analysis of bunkering and pressurization for marine LNG fuel tank
Authors: Wang Cheng , Ju Yonglin
Published: June 2022

Liquefied natural gas (LNG) is becoming an ideal alternative fuel for vessels because of its environmental and economic advantages. As LNG is a cryogenic fuel stored around -163 °C, the LNG fuel tank is a highly non-equilibrium thermodynamic system especially during bunkering and pressurization processes. The accurate prediction of the thermodynamic behaviors inside the LNG fuel tank is critical for the system design and operation. In this study, a fast and effective analytical model of bunkering and pressurization for marine LNG fuel tank was developed. The Norwegian car ferry MF Korsfjord was chosen as a benchmark case to confirm the validity of the model. The top spray filling process, the pressurization process, and the fuel gas supply process of the MF Korsfjord were simulated. The model prediction showed good agreement with the measured data. Besides, cryogenic liquid sloshing inside the fuel tank was investigated as well. The results showed that the sloshing had a severe impact on the tank pressure, especially when the resonance condition of the tank was met, resulting in the shutdown of gas engines in extreme situations.
Numerical computation of Boil off Rate (BoR) in shipboard LNG tanks
Authors: Eswara A K , Sandilya P
Published: June 2022

Natural gas is an environment-friendly fuel and a raw material for many chemicals. Its offshore transport is economical when the gas is transported in liquefied form as Liquefied Natural Gas (LNG) over distances (exceeding 2000 kilometers) by sea. LNG is stored at near-atmospheric pressure and about 112 K in these tanks. Heat inleak from the ambient into the stored LNG causes considerable boil-off of the LNG due to low latent heat of vaporization of LNG. Boil off Gas (BoG) generation should be reduced to minimize the loss of LNG as well as environmental pollution. Determination of the boil-off rate (BoR) poses a challenge because it involves interplay of multitude of phenomena and considerations, like liquid sloshing that is likely to generate heat and increases the interfacial area between the liquid and the ullage, variation in LNG composition due to BoG generation, and thermal stratification. In this paper we present a numerical analysis of the BoG generation, including some of the effects just mentioned. A model including transport phenomena based-equations and thermodynamic phase relations has been developed for this purpose.The simulation results would help in carrying out more in depth study of BoG generation that is useful in the design and operation of the prismatic membrane tanks.
Experimental investigation of valve driven transient effect in liquid nitrogen pipeline
Authors: Bhuvana R G , Singh Gour Abhay , Ghosh Parthasarathi
Published: June 2022

Liquified cryogenic fluids like Liquid oxygen, nitrogen, and hydrogen have various industrial applications. The cryogenic fluid transfer lines are generally fitted with valves to regulate, and control flow. The sudden operations of these valves lead to transient effects characterized by pressure fluctuations. The severity of pressure oscillations depends on various parameters including the valve parameters and the fluid properties. The fluid properties of cryogenic fluid in turn vary rapidly during such valve transients. In this work, a Cryogenic test facility is developed to investigate the valve-driven transients in a liquid nitrogen pipeline. The effect of the transient in the system is evaluated for two different cases of tank pressure and flow rate. The behavior of the transient is detected with the help of dynamic pressure sensors and RTD sensors. Further, the results are interpreted to understand the effect of the transient in the cryogenic fluid transfer system.
A novel system for measuring effectiveness of magnetic shields in a liquid helium Dewar with a fluxgate magnetometer
Authors: Wei L , Wang G , Hong G , Wang L , Quan J
Published: June 2022

A novel system which is specially designed for measuring effectiveness of small-scale magnetic shields in a liquid helium Dewar is introduced in this paper. This system is mainly applied to test the shielding performance of multilayer magnetic shielding structure which is used in the field of single-flux-quantum (SFQ) electronics testing at liquid helium temperature. This system allows using a fluxgate magnetometer to measure the magnetic flux instead of the superconducting quantum interference device (SQUID) method. The fluxgate magnetometer can be put into the system through a circular channel which is connected with the ambient environment. Thus, both the shielding effectiveness and the absolute magnetic flux can be obtained by this system. In addition, this system is designed with the shielding of the interference of environmental magnetic field, which improves the measurement accuracy. By utilizing this system, the magnetic shield effectiveness of a four-layer magnetic shields manufactured with low-temperature permalloy material and superconducting material was measured. The experimental results shows that the axial shielding effectiveness (SE) is 58.3 dB. The comparison between the experimental and theoretical results verified the effectiveness of this system.
Design of a cryogenic two-phase flow visualization system for cryogenic pulsating heat pipe
Authors: Lyu Bingkun , Xu Dong , Nishimura Arata , Li Laifeng
Published: June 2022

A cryogenic pulsating heat pipe (PHP), as a novel two-phase heat transfer device, has been studied for cooling superconducting magnets because of its high transfer coefficient, simple configuration, and flexible arrangement. From the results of the room temperature PHP experiments, it was noticed that the flow characteristics and the flow pattern of the PHP are complex, which affect the heat transfer performance of the PHP. In this work, a cryogenic two-phase flow visualization system for cryogenic PHP by using a GM cryocooler is developed to get a better understanding of the oscillating behavior, the distribution of vapor slug and liquid plug, and the flow pattern of the cryogenic working fluid. The details of the design of this system are presented. The performance of the GM cryocooler is verified and the temperature distribution of the cooling system is discussed. The liquid slugs and vapor bubbles were observed during the cool-down period. The visualization experiment will be carried out with the cryogenic PHP prototype installed and operated in a vertical position using nitrogen as a working fluid.
Simulation and experimental research on the thermal resistance of Cernox sensors in different bonding ways based on a high-precision cryogenic temperature measuring system
Authors: Qin H L , Zhou G , Li Q
Published: June 2022

The model for measuring thermal resistance according to self-characteristic between the Cernox thin-film sensors and the test sample is established by the precise cryogenic thermostat, and the simulation is as well accomplished by COMSOL solid heat transfer module. Furthermore, thermal resistance comparison experiments using three different mounting mediums, namely GE Varnish 7031, TRA Bond 2115, Apiezon N grease, and one no glue or grease are researched in various cryogenic temperatures and exciting currents. The measuring data and uncertainty are analyzed and corrected by the multi-current method. Depending on the experimental results, the proposal of the sensor installation medium is presented for different cryogenic environments and requirements.
Small scale time projection chamber setup to test the purity of liquid krypton from the NA62 experiment at CERN
Authors: Liberadzka-Porret J , Koettig T , Santandrea D , Kriboo R , Velghe B , Bryman D , Falaleev V , Danielsson H , Bremer J
Published: June 2022

A high liquid krypton purity level is essential for the NA62 calorimeter at CERN to ensure long lifetimes of the ionization electrons in the detector. A small time projection chamber (TPC) system was developed to enable the measurement of liquid krypton purity at the oxygen equivalent ppb level. This paper describes the dedicated cryogenic setup and the procedures required to operate the purity monitor system, while guaranteeing the condensation of krypton at 119 K without freezing it at 115.8 K on the cryocooler-based heat exchanger. The focus is on the materials used, and the instrumentation and pressure safety equipment that allowed the bake-out and purging procedures to reach ppb levels of impurities in the two litre vessel containing the TPC. The setup was integrated in the NA62 experimental area and successfully tested with purified commercially obtained krypton.
A research on silver powder sinters for dilution refrigerator heat exchangers
Authors: Pan Z J , Wei L J , Zheng M W , Liang J T , Zhao M G , Liu Y J
Published: June 2022

Due to the Kapitza resistivity, a sharp deterioration of heat transfer occurs between solid and liquid in the heat exchanger of the dilution refrigerator at extremely low temperature. It is necessary to use silver powder sintered heat exchangers to optimize the interface heat transfer. A theoretical calculation of heat exchangers at extremely low temperature was carried out to analyze the influence of the Kapitza resistivity on heat transfer performance. Silver powder with different particle sizes of 80 nm, 200 nm and 500 nm were selected for the preparation of sinters. Their micro-scale sintering conditions, pore volumes and specific surface area were carefully presented. It can be concluded from the theoretical calculations and the experimental results that the 200 nm silver powder sinters can optimize the performance of dilution refrigerator heat exchanger with a large heat exchange area.
Dynamic simulation of the target moderator cryoplant and cryogenic transfer line at the European Spallation Source
Authors: Chao Y , Weisend J G , Arnold P , Gan Z
Published: June 2022

Large scale helium cryoplant is an important sub-system in large science facilities. Dynamic simulation by computer is proved to be an effective method to design and optimize large scale helium cryoplant. This study builds a dynamic simulation model for the Target Moderator Cryoplant and the cryogenic transfer line in European Spallation Source using Dymola and Modelon library. This cryoplant can provide 30.3 kW cooling power at 15 K. The main parts of the system including the screw compressor, turbine, heat exchanger, warm gas buffer and gas management panel are simulated. The model is verified by the acceptance data. Dynamic simulation is carried out to study the cooling down process and transient heat load scenarios. The influence of the cryogenic transfer line to the cryoplant is analysed according to simulation results. This simulation could predict the response of the cryoplant to transient heat load and benefit the steady operation of the cryoplant.