Saturated Vapor Research Articles

A theory of rheological film condensation

The article provides a theoretical investigation of the laminar film-condensation of shear-thinning fluids onto an isothermal, vertical plate in the presence of gravity, interfacial shear, wall friction, and inertia. The liquid motion occurs toward gravity, overcoming the resistances of interfacial shear, wall friction, and inertia. The liquid motion induces momentum to the adjacent stagnant saturated vapor by interfacial shear. The vapor motion, in turn, influences the liquid film’s heat transfer and fluid dynamics. For film condensation, it is well-known that the film, along the length of the plate, can be grouped in two separate heat transfer regimes, viz. conduction-dominated regime and convection-dominated regime. For the first time, we have identified three distinct fluid dynamic regions across the film (viz. R1, R2, and R3) unique to power-law fluids. R1 is bounded between the condensing surface and the locus of Newtonian shear stress. R2 is bounded between the locus of Newtonian shear stress and the locus of zero shear stress. Beyond R2, R3 is stretched up to the liquid-vapor interface. The transverse temperature gradient is subtly different in these three fluid dynamic regions. We examine flow physics on a non-dimensional platform. The critical role of the power-law index in determining wall-friction and condensate’s mass flow rate and the impact of liquid Prandtl number in achieving the degree of subcooling has been nicely illustrated. We expose various limiting conditions for simplifying the robust mathematical theory. An analytical expression for the liquid’s longitudinal velocity has been derived, neglecting inertia and interfacial shear.

Numerical study of condensation heat transfer performance and liquid film distribution characteristics in small-scale helium liquefiers

At present, the liquefaction rate of small-scale helium liquefiers using 4 K cryocoolers is generally low. Helium condensation, the most critical heat transfer process in the system, is seldomly studied, and the design of condenser lacks accurate theoretical guidance. In this study, a CFD model for the film condensation of helium on the surfaces of condensers in small-scale helium liquefiers was established and verified. Compared with cryogenic fluids such as nitrogen, in the condensation of helium, the temperature difference and thermal resistance between the gas-liquid interface and saturated vapor cannot be ignored under small condensation temperature differences. On different surfaces of a cylindrical condenser, the thickness of liquid film on the vertical surface is lower than those on the horizontal surfaces, and its heat transfer coefficient is 1–3 times than those of horizontal surfaces. When the cooling capacity increases from 1 W to 2 W at 4.21 K, with the increase of the condensation temperature difference and thermal resistance brought by liquid film, the average heat transfer coefficient of condenser decreases from 530 W/(m2 K) to 446 W/(m2 K), the condensation efficiency decreases by 11.7 %. This study aims to provide theoretical guidance for the optimal design of the helium condensers in small-scale helium liquefiers.

Laboratory equipment for practice learning in the framework of educational course “Molecular Physics and Thermodynamics”

This article presents laboratory equipment for practice learning of physics specialties students in the framework of educational course “Molecular Physics and Thermodynamics”. The presented laboratory equipment allows measuring the temperature dependence of the thermal conductivity coefficient of molecular liquids under atmospheric pressure and saturated vapors pressure in the temperature range from 150K to 400K. A general scheme of the developed experimental setup for measuring the thermal conductivity of liquids by the steady-state method under isobaric condition has been described. The created laboratory setup uses general design solutions of the coaxial cylinder method, preserving its features and measurement precision in general. The measurements are carried out on coaxial-geometry cell under atmospheric pressure. A modified heat potentiometer method with one thermometer was used, which allowed us to minimize the error in the estimation of the thermal conductivity coefficient due to the uncontrollable heat flows and different calibration of thermometers. The total systematic error in the measurement of the molecular liquids thermal conductivity does not exceed 3%. The procedures for direct measurement and calculation of the thermal conductivity coefficient of molecular liquids using the developed laboratory equipment are described.

Research on the thermodynamic properties of binary mixtures containing R1234ze(E) based on Helmholtz model

R1234ze(E) has excellent environmental protection properties, but the unsatisfactory latent heat of vaporization and volumetric cooling capacity impede its application. A mixture with excellent thermophysical properties and environmental performance can be obtained through blending R1234ze(E) with other working fluids. In this paper, the vapor-liquid equilibrium data of R1234ze(E)/R32, R1234ze(E)/R152a, R1234ze(E)/R290, and R1234ze(E)/R161 were correlated by Helmholtz equation of state combined with the mixing rule, and the calculation model of thermodynamic properties was established. On this basis, temperature glides, latent heats of vaporization, saturated vapor pressures, and other thermodynamic properties of binary mixtures containing R1234ze(E) were calculated and compared. The results indicate that the standard boiling points and critical temperatures of the four binary mixtures containing R1234ze(E) were similar to those of R22 in most mass concentration ranges. And their saturated vapor pressures at 298.15 K were all lower than that of R22 except for R1234ze(E)/R32 mixed in a few proportions. The latent heat of vaporization and specific heat capacity at a constant pressure of the four mixtures were larger than those of R1234ze(E) and adding the four pure refrigerants with excellent thermodynamic properties into R1234ze(E) helps to improve the latent heat of vaporization and specific heat capacity of the binary mixtures. Among the four mixtures, R1234ze(E)/R290 is an azeotropic mixture and R1234ze(E)/R152a is a non-azeotropic mixture. Finally, the recommended mixing ratios of R1234ze(E)/R32, R1234ze(E)/R152a, R1234ze(E)/R290, and R1234ze(E)/R161 to replace R22 were in the range of 0.56/0.44∼0.76/0.24, 0.58/0.42∼0.71/0.29, 0.27/0.73∼0.85/0.15, and 0.58/0.42∼0.84/0.16.

Exfoliation mechanism of AlGaN-based thin films using heated-pressurized water

This study investigated the crystallographic plane dependence of the reaction of AlN and AlGaN using heated-pressurized water under saturated vapor pressure. The results show that the reaction strongly depends on the crystallographic orientation plane, with no reaction in the +c-plane, the formation of an AlOOH-altered layer in the −c-plane, and etching in the a- and m-planes. These results suggest that the exfoliation mechanism of AlGaN grown on periodically formed AlN nanopillars on sapphire substrates using heated-pressurized water involves etching of a- and m-plane crystals, demonstrating that the proposed method is highly reproducible and versatile for large-diameter wafer exfoliation.

A dataset of carbon and water fluxes in the Changling alkali-saline paddy rice fields in the Songnen Plain, China (2018 –2020)

Compared with other terrestrial natural ecosystems, the land-atmosphere interaction in managed farmland ecosystem is more complex and changeable, due to the effect of crop types, cropping pattern, management practices, etc. As one of the most effective measures against the process of land alkalization and salinization in the Songnen Plain of Northeast China, paddy rice planting after desalination highly representative model for studying climate mitigation, water use and carbon balance. To support this approach effectively, it requires comprehensive field monitoring data. The eddy covariance method, grounded in micrometeorological theory, is widely recognized as the primary and direct approach for measuring CO2 and H2O exchanges in farmland ecosystems. This dataset comprises field measurements of Changling alkali-saline paddy rice during 2018–2020 subjected to rigorous quality control and gap filling in accordance with the ChinaFLUX data processing criteria. The dataset specifically includes half-hourly, daily, monthly and yearly scales of air temperature (Ta), air relative humidity (RH), water vapor pressure (e), saturated water vapor pressure (es), soil temperature (Ts), soil water content (SWC), net radiation (Rn) with four components, photosynthetically active radiation (PAR), rainfall (P), wind speed (Ws), wind direction (Wd), sensible heat flux (Hs), latent heat flux (LE), evapotranspiration (ET), net ecosystem CO2 exchange (NEE), ecosystem respiration (Re), gross ecosystem exchange (GEE), etc. The establishment and sharing of this dataset can offer valuable data support and a solid theoretical foundation for regional farmland ecosystem assessment and management.

Synthesis, crystal structure, thermal properties of a homoleptic Schiff base cobalt complex bis(N-tert-pentyl salicylaldimine)cobalt(II) as precursor for coating Co3O4 thin film by a plasma enhanced MOCVD

A Schiff base complex of cobalt namely, bis(N-tert-pentyl-salicylaldimine)cobalt(II) (2) was synthesized by treating the parent complex, bis(salicylaldehydato)cobalt(II) (1) with n-tert-pentylamine in a methanolic medium. Complex 2 was analysed by dynamic TG/DTA using high purity Ar as purge gas at ambient pressure and was found to be volatile without undergoing decomposition leaving a negligible amount of (1.8 %) residue at 322 °C after melting sharply at 155 °C. The parent complex (1) wherein four oxygen atoms are coordinated to cobalt yielded a residue of 58 % at 400 °C. The dissimilarity in thermal property of 2 (CoN2O2) from that of 1 (CoO2O2) arises from the bonding of nitrogen atoms to cobalt by introducing n-tert-pentylamine which caused replacement of aldehyde O (–CH = O) with azomethine nitrogen (–CH = N). Single crystal XRD analysis of complex 2 revealed it to crystallise in orthorhombic crystal system with a space group of P212121. Further 2 was characterised by FTIR, elemental analysis and mass spectrometry. Transpiration TG technique was employed to evaluate the temperature dependence of saturated vapour pressure (pe) and enthalpy of vaporization (ΔvapH° = 102.3 ± 2.5 kJ mol−1) for 2 in the temperature range of 443–545 K. Complex 2 was transformed in to Co3O4 thin film at 350 °C in an Ar plasma by using a lab made plasma assisted chemical vapour deposition (CVD) process at 1.2 mbar deposition pressure. XRD revealed a preferential growth of cubic Co3O4 in the (311) plane. The SEM images confirmed a dense but scattered growth of cauliflower shaped structures. The particle size was found to be 19.3 nm. Kubelka-Munk function yielded a band gap of 2.01 eV.

Observed decreasing trend in pan evaporation in a tropical rainforest region during 1959–2021

Abstract Pan evaporation (Epan) is a critical measure of the atmospheric evaporation demand. Analyzing meteorological data from the Tropical Rainforest Comprehensive Meteorological Observation Field in the Xishuangbanna Tropical Botanical Garden (XTBG Meteorological Observing Station) based on physical models is helpful to improve our understanding of the state of the hydrological cycle in the Xishuangbanna tropical rainforest region. In this study, we investigated the long-term trend in Epan using the observation data from 1959 to 2021. Moreover, correlation analyses of Epan were performed, such as trend test, assessment of periodic properties and abrupt change analysis. Then, D20 Epan data and related meteorological data from 1979 to 2008 were used to drive Penman‒Monteith and PenPan models for simulating Epan. The partial derivative attribution method was used to analyze the dominant factors affecting Epan. The results showed that Epan exhibits obvious periodic changes, the 19a is the first primary period. In addition, there was a clear ‘evaporation paradox’ phenomenon in Xishuangbanna. Epan showed a decreasing trend during both 1959–2008 and 2009–2018, and the decreasing trend reached a significant level with a rate of −3.404 mm·a−2 during 1959–2008. Through comparative analysis, the PenPan model was considered more suitable for simulating Epan in Xishuangbanna. In order to identify the main meteorological factors influencing Epan, complete data from the D20 pan monitoring period, namely, 1979–2008, were selected for attribution calculations. The variations in the net radiation and saturated vapor pressure deficit are the main triggers that explain the ‘evaporation paradox’ phenomenon in Xishuangbanna.

Liquid−vapor order parameter and coexistence-curve diameter of nitrogen, ethylene, and sulfur hexafluoride: From the triple point to the critical scaling regime

Analytic closed-form expressions are obtained for the liquid and vapor saturation densities defining the coexistence curve. The densities are modeled with broken power laws and Weibull distributions. Specifically, the coexistence curves of nitrogen, ethene and sulfur hexafluoride are derived, without the use of perturbative expansions, based on high-precision data extending from the triple point into the critical regime. The analytic continuation of the vapor branch below the triple point decays exponentially at low temperature. The order parameter and coexistence-curve diameter of the fluids are assembled from the regressed liquid and vapor branches of the coexistence curve, and the critical power-law scaling of these quantities is examined. The scaling exponents of the order parameter and the reduced diameter are regressed and compared with the calculated critical exponents of the 3D Ising universality class. Index functions representing the Log−Log slopes (temperature-dependent effective exponents) of the liquid and vapor densities, order parameter and diameter are used to determine the onset of the ideal power-law scaling regime and to illustrate the slope evolution of these quantities in the subcritical regime.

Experimental investigation of evaporation characteristics of sessile fuel droplets on a hot surface

Spilled fuel that comes in contact with hot surfaces can cause a fire, and to mitigate this type of fire, we researched the evaporation patterns and heat transfer mechanisms of fuel droplets on such surfaces. Glass heating substrates were used to experimentally investigate the evaporation behavior of acetic acid, ethanol, acetone, ethyl acetate, n-heptane, and cyclohexane. Infrared imaging technology and volume estimation method were used for the experimental analysis. The study revealed various thermal patterns on the surfaces of different droplets. Hydrothermal waves (HTWs), Bénard-Marangoni (B-M) cells, cyclic thermal patterns, and double-vortex thermal patterns were observed on different types of fuel droplet surfaces. The energy absorption and breakage of intermolecular hydrogen bonds are related to the formation of HTWs and B-M cells. As the height of the droplets decreased, the rate at which the six fuel droplets evaporated was observed to decrease initially and then increase. The results of this experiment indicate that the evaporation rate of droplets is largely determined by the saturation vapor pressure.

The physical, mechanical and fire performance of bamboo scrimber processed with thermal-treated bamboo bundles

Thermal treatment is gaining increasing attention for bamboo modification in practical production due to its advantages of simplicity, effectiveness and environmental friendliness, particularly in the production of bamboo scrimber. The objective of this study is to investigate the effects of two typical thermal modification methods on the physical, mechanical and fire performance of bamboo scrimber, as well as the related physicochemical properties of bamboo bundles for production purpose. The results indicated that the two types of bamboo scrimber processed distinct advantages in terms of physical and mechanical performances. Specifically, the one processed with bamboo bundles treated by superheated steam at a temperature of 200 ℃ (referred to as the “HL group”), exhibited exceptional dimensional stability and fire resistance, while exhibiting slightly lower mechanical properties. Notably, the HL group exhibited a significantly more pronounced hue compared to the LS group, which was treated with saturated vapor at a temperature of 140 ℃. Both demonstrated exceptional water resistance, with the HL group surpassing that of the LS group in either 24-hour room temperature or a combination of boiling-drying cycling treatments. The MORs of the LS group were determined to be 152.3 MPa and 108.5 MPa under dry and wet conditions, respectively, exhibiting significantly higher values than those observed in the HL group. Conversely, the variation of MOEs was found to be opposite. Both MORs and MOEs of the two groups exhibited a significant decrease in wet condition compared to those in dry condition, with reductions linearly correlated to water absorption of the samples. The failure mode of the LS group demonstrated elastoplastic failure characterized by a “Z-shaped”, while the HL group exhibited with a relatively flat cross-section. Furthermore, the HL group demonstrated superior fire performance in comparison to the LS group, and as evidenced by a significantly denser char residue surface with fewer and wider cracks than that of the LS group. The variations of chemical components and microstructures in bamboo can be attributed to variances in the extent of degradation of hemicellulose, lignin, and even cellulose during the thermal modification processes. The water resistance, dimensional stability and fire performance of bamboo scrimber can be significantly improved through thermal treatment, while resulting in a decrease in MOR, particularly for the HL group. The HL and LS groups of bamboo scrimber both exhibited excellent performances, making them suitable for application as structural engineering materials. The work we conducted offers experimental and theoretical support for improve the pre-treatment procedures of bamboo in the manufacturing of bamboo scrimber for structural utilizations.

Method for Obtaining Isothermal Diagrams of the Liquid - Vapor Equilibrium for the System as Dimethyl Zinc - Dimethyl Telluride

According to the obtained experimental temperature dependences of the saturated vapor pressure on dimethylzinc – dimethyltelluride solutions with dimethylzinc content of 50.0 and 70.32 mol. %, isothermal sections (280, 290, 300, 310, and 320 K) were made. For the dimethylzinc – dimethyltelluride system based on a limited set of experimental data for the “liquid-vapor” equilibrium, the vapor composition was calculated according to the Duhem – Margules equation, as well as the partial pressures and the distribution coefficient.

Operational characteristics of the super-long gravity heat pipe for geothermal energy exploitation

As a novel geothermal heat transfer technology, the super-long gravity heat pipe (SLGHP) demonstrates great potential for the efficient exploitation of deep geothermal energy. Despite the rapid advances made to the SLGHP technology, its operational characteristics remain to be fully investigated. In this study, the underlying phenomenological mechanisms of the SLGHP are compared with those of normal-size gravity heat pipes (NSGHPs), and the operational characteristics of the SLGHP are analyzed in view of its distinctive geometric features. It is noted that the thermal resistance caused by the vapor flow is negligible in the NSGHPs, while it dominates the overall thermal resistance of the SLGHP. The dominance of the vapor flow thermal resistance allows making the one-dimensional simplification (along the pipe length direction) in the mathematical model of the SLGHP geothermal energy extraction system. Under these circumstances, the temperature gradient along the SLGHP length can be theoretically deduced based on the pressure drop of vapor flow. Close observation of the temperature gradient expression indicates that the desirable SLGHP working fluid should have the following properties: i) large latent heat of vaporization, and ii) a strong dependence of the saturated vapor pressure on the temperature. In cases where the saturated vapor pressure of the working fluid is highly dependent on the temperature, as in the case of ammonia, the working temperature profile of the SLGHP can be formulated as a linear function of the depth. This unique working temperature characteristic offers valuable guidance to determine the length of the SLGHP adiabatic section in practical geothermal applications. The on-site observed operational characteristics provide the necessary theoretical foundation for modeling the multiphase heat transfer process in SLGHP, which will lead to a valuable engineering analysis and design tool supporting the application and commercialization of the SLGHP technology.

Investigation of the operation characteristics and optimization of an alkaline water electrolysis system at high temperature and a high current density

Increasing the operating temperature of water electrolysis is an effective way to improve its performance. When the available region of the operating current density is extended, the stack can generate an increased amount of hydrogen. This can directly contribute to green hydrogen being highly competitive compared to other kinds of hydrogen. In this study, numerical analysis was conducted to investigate and optimize the operational characteristics of alkaline water electrolysis (AWE) under high temperature and high current density conditions. The numerical model of the AWE developed in our previous study has been upgraded by considering the crossover of hydrogen gas through the membrane to more accurately determine the Faraday efficiency of hydrogen production and the available safe operating range. Simulation results show that saturated vapor generation significantly affected the performance of both stack and system components in high-temperature environments. Therefore, pressurization is important to ensure the high efficiency of high-temperature water electrolysis, but it must be appropriately adjusted in consideration of gas crossover. In this study, the highest efficiency of 78.52% was captured at 120 °C and 10 bar for 1 A/cm2 operation.

Verification of Reinforced Surface Loose Layer of Zinc-Aluminum-Magnesium Steel Plate.

The corrosion resistance of zinc-aluminum-magnesium steel plates (Zn-Al-Mg steel plates) is significantly higher than that of galvanized steel plates. However, the unsatisfactory bonding performance of Zn-Al-Mg steel plates significantly limits their widespread application. In this study, X-ray photoelectron spectroscopy is employed to detect changes in the surface oxygen content of Zn-Al-Mg steel plates after different temperature treatments to confirm the existence of surface loose layers. In particular, changes in the surface oxygen content of the Zn-Al-Mg steel plates after the oxide layer is removed are investigated under saturated H2O vapor and O2 environmental conditions, and the cause of the formation of loose surface layers is determined. The uneven distribution of elements on the surface of the Zn-Al-Mg steel plates is investigated with scanning electron microscopy and energy dispersive spectroscopy. Nuclear magnetic resonance is employed to determine the size of the network spatial structure formed by silane coupling agents under different hydrolysis conditions and to further investigate the bonding performance of hydrolysate-modified Zn-Al-Mg steel plates. Several typical automotive adhesives are utilized to compare and examine the changes in the tensile strength of the Zn-Al-Mg steel plate bonding before and after modification with the silane coupling agent and analyze the structural damage of the adhesive at the bonding interface. The results confirm that the silane coupling agent strengthens the loose layer on the surface of the Zn-Al-Mg steel plate.

New Thermodynamic Equation of State for Refrigerant HFO-1243zf

R-1243zf is a new refrigerant that could replace R-134a. Its thermodynamic properties represented in the equation of state (EOS) play an essential role in analyzing and designing thermal systems. The EOS exists without including caloric property data due to unavailable data during the development time. New EOS was developed explicitly in Helmholtz free energy and optimized to represent the experimental data accurately and maintain thermodynamic consistency. The optimization process undergoes using a genetic algorithm and weighted-least squares regression. The experimental data used in the optimization have a range of 233–430 K and 0.106–34.6 MPa and were validated from the extrapolation and consistency to confirm the reliability. The average absolute deviation from the data is 0.48% for the ideal gas isobaric specific heat, 1.7% for the isochoric specific heat, 0.33% for the speed of sound, 0.22% for the liquid density in single-phase, 0.49% for the vapor density in single-phase, 0.96% for the vapor pressure, 2.2% for the saturated liquid density, and 3.2% for the saturated vapor density. The EOS has a reasonable extrapolation behavior from the triple point up to 700 K and 100 MPa.

Significant Increases in Water Vapor Pressure Correspond with Climate Warming Globally

Global warming has become indisputable in recent years; however, the mechanisms by which water vapor, radiation, and greenhouse gases such as carbon dioxide contribute to driving global warming remain unclear, and it is becoming increasingly important to clarify their respective effects on temperature warming. In this study, we used the Global Land Data Assimilation System (GLDAS) datasets and National Oceanic and the Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) data to investigate the spatiotemporal variation characteristics of global warming and its driving mechanisms. The effects of water vapor, radiation (net longwave radiation), and CO2 on temperature rise are quantified from the perspective of the coupled land–atmosphere system, and water vapor is characterized in terms of the vapor pressure deficit (difference between saturated and actual water vapor pressures) to explicitly characterize its impact on the global water–heat cycle. The results show the following: (1) Under significant global warming, the vapor pressure deficit (VPD) exhibits an increasing trend, which is attributed to the rate of increase in actual water vapor being relatively slower than saturated water vapor. (2) Compared with the significant positive contribution of water vapor to global warming, CO2 is not, as generally expected, the most critical greenhouse gas causing global warming. (3) Water vapor and net longwave radiation (NLR) have significant mutual feedbacks on global warming. (4) A remarkable complementary mechanism of global warming that involves water vapor and NLR was identified, whereby the increased saturated water vapor induced by the rising temperature dominates the decrease in NLR. The results from this study have important theoretical value by enabling a more complete understanding of the contribution of VPD to global climate change and shedding light on the large-scale water vapor–climate change mutual feedback mechanism through research.

Application of electron beam welding technique for joining coarse-grained and ultrafine-grained plates from Al-Mg-Si alloy

In the present work, the attempt to weld coarse (CG) and ultrafine-grained (UFG) Al-Mg-Si alloy using an electron beam welding technique has been taken. Welding parameters were selected in a way to reduce the energy input, and thus the heat-affected zone (HAZ) and the evaporation of elements with high saturated vapor pressure. The UFG microstructure was beneficial in obtaining smaller grains in the fusion zone (FZ) and HAZ, resulting in higher mechanical strength than weldments from CG Al-Mg-Si alloy. The weld efficiency for CG alloy was 80 %, while for the UFG sample - 68 % (82 %, compared to CG base material). The reasons for a drop in mechanical properties in the FZ were a dissolution of strengthening precipitates and an increase in grain size. Also, the evaporation of Mg (alloying element) and Zn (impurity) occurred to a larger extent. The rupture in both welds occurred in the columnar dendritic area in the FZ, characterized by the elongated dendrites and cube texture that favoured the rupture.

The acute vapour inhalation toxicity of 2-butoxyethanol. Points considered when designing and conducting a study in Guinea pigs and evaluating existing inhalation toxicity data on low volatility solvents

This publication reports the outcome of an acute inhalation toxicity study with guinea pigs by nose-only exposure to the substance 2-butoxyethanol at exposures close to the maximum attainable saturation vapour concentration. We describe the methods used to ensure exposure only to saturation vapour at a level as high as could be practically achieved whilst avoiding aerosol formation. We consider the practical difficulties and implications of testing substances at or close to their saturation vapour concentration and the criteria that should be used to critically assess such studies, especially with reference to the GHS (Globally Harmonised System) for classification and labelling, where a clear differentiation between gases, vapours and dust and mists applies. Guinea pigs showed no adverse effects when exposed for 4 h to the maximum attainable concentration of pure 2-butoxyethanol vapour. If guinea pigs are regarded as the most appropriate species to assess short term toxicity to humans from exposure to 2-butoxyethanol, because they are like humans not sensitive to haemolysis of red blood cells caused by exposure to the substance, then the data from this study shows that 2-butoxyethanol presents a low acute inhalation toxicity hazard.

Импульсные источники ИК-излучения с разрядом в смеси паров щелочных металлов

The paper presents results of research aimed at improving the serial pulsed sources of the IR-radiation based on a discharge in the cesium-mercury-xenon vapor mixture. To create the environmentally friendly gas-discharge source and increase the peak radiation strength, it proposes to replace the mercury buffer in a serial lamp with the rubidium vapor. Based on the thermodynamic analysis, necessity of using cesium as the main component in the plasma-forming medium of IR-radiation pulsed sources was proved. It was established that introduction into the cesium discharge of less than the 25 % (wt.) rubidium provided the required cesium vapor pressure and the plasma thermal conductivity. It was shown that the mass of the alloy with cesium played an important role in the discharge transition from unsaturated to the saturated vapors. Comparison results are presented in peak intensity of the studied IR-radiation gas-discharge lamps depending on amplitude and duration of the supply voltages in the repeated pulsed mode. A technique was developed to compare energy efficiency of the discharges under study, and the spectral research was performed confirming advantages of the IR-radiation pulsed source based on the cesium-rubidium-xenon discharge by the serial gas-discharge lamps