Lower Temperature Type Research Articles

Exploring geothermal resources with the CSAMT and microtremor methods: a case study in Tangquan, Jiangsu Province, China

The development of geothermal energy has received extensive attention because of global energy scarcity and environmental pollution. The Tangquan area is in the north of the Yangtze fold belt, and the lack of magmatic rock development has resulted in a low-temperature type of geothermal reservoir. There are sporadic hot springs and cold springs exposed in the study area, but the uncertain deep geological structure, unknown geothermal reservoir formation mechanism, and lack of detailed exploration data seriously restrict the exploration and development of geothermal resources in the area. Filling underground faults with water can significantly reduce electrical resistivity, while traps filled with warm water can cause a decrease in S-wave velocity. Thus, a new integrated geophysical method, including the controlled source audio-frequency magnetotelluric (CSAMT) and microtremor methods, is applied for geothermal exploration in the region. The combination of CSAMT and microtremor methods can determine thermal-controlled and water-conducting structures more effectively and locate geothermal storage more accurately. The source, channel, storage, and cover of regional geothermal reservoir formation are analyzed using geophysical and geological data. That is, the regional NE- and NW-trending faults are explained as thermal-controlled and water-conducted structures, respectively. The deep Sinian Dengying Formation supplies a heat- and water-bearing space. The tectonic intersection area, especially the tensional fault zone, is found to be closely related to the existence of geothermal reservoirs, which is well verified by later drilling results. Finally, a geothermal reservoir model is established to comprehensively understand the distribution of geothermal energy in the region.

Study on fluid inclusions and stable isotopics of W–Mo ore deposits in the Ningshan–Zhen’an area, South Qinling, China

The study of the fluid inclusions of W–Mo deposits in the mineralization area of Ningshan–Zhen’an , Shaanxi Province, China shows that the gas–liquid two-phase inclusions are mainly present in W–Mo deposits, and the ore-forming fluid can be divided into four types: high-temperature type, middle–high-temperature type, middle-temperature type and low-temperature type. The formation depths of the W–Mo mineralization range from 4.2 to 8.4 km. The boiling and mixing of fluid may have been important mechanisms for the formation of W–Mo mineralization. The skarn-type mineralization is dominated by magmatic water, the quartz-vein-type mineralization includes both magmatic water and meteoric water, and the meteoric water is more involved in the quartz-fluorite-vein-type, beryl-quartz-vein-type and pegmatite-type mineralization. Magma is the main source of sulfur; that is, magma is the main source of mineralization. Combined with the metallogenic setting and geological characteristics of typical ore deposits, in the process of structural system transformation in South Qinling, the ore-forming magma fluid in the Late Indosinian–Yanshanian period was uplifted and emplaced along the NW–WNW direction and NE–NNE direction, and eventually, NW–WNW fault-controlled skarn-type W–Mo mineralization and quartz-vein-type W–Mo deposits accompanied by greisenization, albitization and potash feldspathization formed.

Significance of serpentinite‐hosted exhumation channels in a palaeo‐subduction complex, Nishisonogi unit, Nagasaki Metamorphic Complex: P–T trajectories of mélange blocks and coherent schists

AbstractSerpentinite mélanges occur as thin horizons up to 350 m thick within coherent schists of the Nishisonogi unit of the Nagasaki Metamorphic Complex located in western Kyushu, which represent serpentinite‐hosted exhumation channels within a Cretaceous subduction complex. This study gives the petrography of coherent schists and various tectonic block types embedded in serpentinite or chlorite‐actinolite schist of the mélange. The P–T conditions recorded in these rocks were compared, to clarify a possible exhumation process and style of the Nishisonogi unit. In the mélange, two types of tectonic blocks were recognized based on peak temperature conditions: a lower temperature type (400–590°C) and a higher temperature type (780–830°C), the latter of which shows temperatures higher than those of the coherent schists (370–450°C). The garnet glaucophanite in the coherent schists shows a prograde pressure increment from 0.9 to 2.3 GPa. The serpentinite mélange comprises tectonic blocks with peak temperatures higher than those of the coherent schists, indicating that blocks from the deep structural levels of the lower‐plate underwent tectonic mixing into the mélange during exhumation. Ultrahigh‐pressure (UHP) conditions have not been recorded either in the coherent schists or in the serpentinite mélanges, although microdiamonds have been reported from the Yukinoura mélange located at the western margin of the Nishisonogi unit (Nishiyama et al., Scientific Reports, 2020, 10, 11645). A possible correlation between the Nishisonogi unit and other HP metamorphic rocks or belts (Renge rocks, Suo Belt and Sanbagawa Belt) was examined to conclude that the Nishisonogi unit is a unique paleo‐subduction complex in terms of the coexistence of HP subduction complex with intercalated serpentinite mélanges and a UHP mélange derived from the slab‐mantle interface.

Enhancing low-temperature characteristics of graphite anode by comprehensive modification of electrolyte

The performance of lithium-ion batteries is significantly deteriorated at low temperatures due to the components’ properties limitations such as the electrolyte viscosity increase and freezing accompanied with a decrease in ionic conductivity, rise of charge transfer resistance, and a substantial capacity loss (over 50 % of room-temperature capacity) in batteries with commercial electrolytes and graphite anodes, even at 0 °C. In this work, a complex modification of lithium salt and solvents of the electrolyte was applied simultaneously to develop an optimal electrolyte system with improved low-temperature characteristics for a Li/graphite half-cell. Various concentrations of commercial and alternative lithium salts (lithium hexafluorophosphate and lithium difluoro(oxalato)borate), dissolved in a mixture of solvents, were studied as electrolytes to determine the best interaction with a graphite electrode at low temperature. A solvent mixture of non-carbonate, low-freezing-point, organic ester ethyl acetate and solid electrolyte interphase (SEI) forming fluorinated co-solvent fluoroethylene carbonate in a ratio of 9:1 was used to prevent freezing of the electrolyte and ensure the formation of a more conductive SEI layer, respectively. The Li/graphite half-cell with the designed electrolyte system has retained about 80 % of its room-temperature capacity at −20 °C, demonstrating a new perspective for the development of low-temperature type electrolytes.

Extreme environmental adaptation mechanisms of Antarctic bryophytes are mainly the activation of antioxidants, secondary metabolites and photosynthetic pathways

The environment in Antarctica is characterized by low temperature, intense UVB and few vegetation types. The Pohlia nutans M211 are bryophytes, which are the primary plants in Antarctica and can thrive well in the Antarctic harsh environment. The transcriptional profiling of Pohlia nutans M211 under low temperature and high UVB conditions was analyzed to explore their polar adaptation mechanism in the extreme Antarctic environment by third-generation sequencing and second-generation sequencing. In comparison to earlier second-generation sequencing techniques, a total of 43,101 non-redundant transcripts and 10,532 lncRNA transcripts were obtained, which were longer and more accurate. The analysis results of GO, KEGG, AS (alternative splicing), and WGCNA (weighted gene co-expression network analysis) of DEGs (differentially expressed genes), combined with the biochemical kits revealed that antioxidant, secondary metabolites pathways and photosynthesis were the key adaptive pathways for Pohlia nutans M211 to the Antarctic extreme environment. Furthermore, the low temperature and strong UVB are closely linked for the first time by the gene HY5 (hlongated hypocotyl 5) to form a protein interaction network through the PPI (protein–protein interaction networks) analysis method. The UVR8 module, photosynthetic module, secondary metabolites synthesis module, and temperature response module were the key components of the PPI network. In conclusion, this study will help to further explore the polar adaptation mechanism of Antarctic plants represented by bryophytes and to enrich the polar gene resources.

Creating Quantitative Regulation Principles of the Heating Networks’ Parameters Based on the Life Cycle Analysis

Materials and Methods. The elaboration of the heating networks should be carried out in compliance with the currently enacted Code of Practices “Information modeling in construction. Rules for the objects’ information model creation at different stages of the life cycle». The life cycle can be divided into four stages. It is noted that each type of digital information model at each stage of the life cycle correlates with the certain level of elaboration, which envisages the minimum of geometric, spatial, quantitative and attributive data necessary to solve the task of information modeling at a specific stage of the object's life cycle.Results. 4th generation heating supply technologies allow reducing the temperature of the heat-carrying agent, hereby creating conditions for commencing the heating networks’ transit to the low temperature type of systems. As a result, reducing the heat carrying agent’s temperature, allows using more flexible polymer materials for the pipelines. In addition, application of the comprehensive approach to the heating networks innovative development is the important prerequisite for further development of the district heating infrastructure and technologies.Discussion and Conclusions. The main focus for improving the heating sector development should lie in the elaboration and implementation of the new technologies and digital information models, which will improve the quality of thermal energy generation, transportation and distribution.

A comprehensive approach to crystallization sequence in novel MgO/CaO-Al2O3-SiO2 glass-ceramics by Ostwald's step rule and composition fluctuation model

An understanding of the crystallization sequence (the formation order of crystalline phases) of glasses is crucial for the processing and composition design of novel glass-ceramics. A comprehensive approach to the crystallization sequence in novel MgO/CaO-Al2O3-SiO2 (MAS/CAS) glass-ceramics was performed from the Ostwald's step rule and the model of the distribution of nanoscale composition fluctuations (DNCF) for the first time. The stoichiometric cordierite Mg2Al4Si5O18 glass exhibits the crystallization sequence predicted by the Ostwald's step rule and a narrow DNCF model, i.e., metastable β-quartz solid solutions (β-QSSs) → high-temperature type indialite → low-temperature type α-cordierite. A broad DNCF model was proposed to present in osumilite Mg2Al4Si11O30 and pyrope Mg3Al2Si3O12 glasses, resulting in the initial formation of β-QSSs or forsterite 2MgO.SiO2 prior to α-cordierite formation. The crystallization sequence in stoichiometric anorthite CaAl2Si2O8 glass was also understood along the Ostwald's step rule and a narrow DNCF model. The importance of nanoscale composition fluctuations, in particular the formation of MgO/CaO-rich fragile regions, was emphasized in the crystallization of MAS and CAS-based glasses having strong Al-O-Si linkages between AlO4 and SiO4 tetrahedra. The present article will contribute to the comprehensive design of new innovative aluminosilicate-based glass-ceramics.

Investigation of the uptake and compatibility behaviors of special disperse dyes developed for sustainable color matching in supercritical carbon dioxide

The uptake and compatibility behaviors of nine developed special disperse dyes belonging to different temperature groups were investigated for the first time on polyester fabric to achieve appropriate dyes for sustainable color matching in supercritical fluid of carbon dioxide (SCF-CO2). Different temperature-rising dyeing rate curves for the special dyes were established and employed to explore their uptake behaviors, compatibilities and other performances in SCF-CO2. Furthermore, the dye uptake behaviors and coloration compatibilities were also investigated at different system temperatures, pressures and dyeing durations. Then, a practical color matching was further carried out by utilizing low-temperature group dyes as a model in SCF-CO2. The obtained results show that an overall satisfactory uptake and compatibility behaviors of the developed dyes were achieved as for sustainable color matching, which were assigned to different temperature types in SCF-CO2. The temperature-rising dyeing rate curves for high-, moderate- and low-temperature type dyes show that very similar uptake behaviors and enhancement tendencies were obtained with the increase of system temperature and duration, accompanied with good coloration performances at uptake ratio ranging from 70 % to 90 % in a large supercritical dyebath. Moreover, significant and similar effects on the uptake behaviors of an individual group dyes from the parameters were achieved, which further indicate that good color matching compatibilities and uptake behaviors for each group dyes were available at different conditions. The practical color matching as well as the monochrome coloration in SCF-CO2 shows that different target shades in gray or various neutral colors, etc., were successfully achieved with low-temperature group dyes, by exhibiting perfect leveling property, high color fastness, which fully met industrial requirements in quality and environmentally friendly characteristics with water free.

Effects of Organic Additives on the Properties of Boronsilicate Glass/Al2O3 Composites Tape Casting Slurries and Green Tapes

Tape casting was a new type of low temperature co-fired ceramic (LTCC) forming process, the key to which was the formation of slurry. Suspensions consisting of boronsilicate glass/Al2O3 powders and organic solvent system were studied, in addition, the effect of solid content and mixing time on the property were also investigated. The results indicated that the optimized parameters of the slurry are 55 wt. % boronsilicate glass/Al2O3 composites powders, the three azeotropic solvents (Ethanol/ Dimethylbenzene/ Dimethylcarbinol=30 wt.%: 10 wt.%: 60 wt.%), 3.0 wt.% dispersant, the ratio of plasticizer to binder(R=0.65), and mixing time (20 hours). The green tape had smooth and homogeneous surfaces without cracks, and the sintered sample had a high relative density.

Evaluate the effect of mocibustion infrared lamps combinded with electroacupuncture in treating sciatica

Objectives: To evaluate the results and unwanted effects of moxibustion-infrared lamps combined with electroacupuncture in treating sciatica.Subjects and methods: A prospective study with open clinical intervention was held, comparing before and after treatment, comparing between two groups of a total of 60 patients (30 each) with a confirmed diagnosis of sciatica according to the criteria of Modern medicine, VAS < 6 points, belongs to the type of low temperature associated with kidney failure of traditional medicine. Treatment group (n=30): Electroacupuncture based on the protocol of the Ministry of Health combined with moxibustion-infrared lamp. Control group (n=30): Electroacupuncture based on the protocol of the Ministry of Health combined with infrared lamp.Results: The method of electroacupuncture combined with moxibustion-infrared lamp had a good effect on the treatment of sciatica by reducing pain and improving the range of motion of the lumbar spine (p<0.05).Regarding the pain level according to the VAS scale, the treatment group had better pain relief than the control group with p<0.05. The treatment group's lumbar spine range of motion improved significantly compared to the control group. The quality of life according to the ODI scale in the treatment group was better than that of the control group (p<0.05). The method of electroacupuncture combined with moxibustion-infrared lamp in treating sciatica did not cause any unwanted side effects in 60 study patients.

Two Strains of Lentinula edodes Differ in Their Transcriptional and Metabolic Patterns and Respond Differently to Thermostress

Temperature type is one of the key traits determining the cultivation regime of Lentinula edodes. However, the molecular and metabolic basis underling temperature type remain unclear. Here, we investigated the phenotypic, transcriptomic, and metabolic features of L. edodes with different temperature types under both control (25 °C) and high (37 °C) temperature conditions. We found that under the control condition, the high- and low-temperature types of L. edodes harbored distinct transcriptional and metabolic profiles. The high-temperature (H-)-type strain had a higher expression level of genes involved in the toxin processes and carbohydrate binding, while the low-temperature (L-)-type strain had a high expression level of oxidoreductase activity. Heat stress significantly inhibited the growth of both H- and L-type strains, while the latter had a higher growth inhibition rate. Upon exposure to heat, the H-type strain significantly up-regulated genes associated with the components of the cellular membrane, whereas the L-type strain markedly up-regulated genes involved in the extracellular region and carbohydrate binding. Metabolome data showed that thermostress altered purine and pyrimidine metabolism in the H-type strain, whereas it altered cysteine, methionine, and glycerophospholipid metabolism in the L-type strain. Transcriptome and metabolome integrative analysis was able to identify three independent thermotolerance-related gene-metabolite regulatory networks. Our results deepen the current understanding of the molecular and metabolic basis underlying temperature type and suggest, for the first time, that thermotolerance mechanisms can be temperature-type-dependent for L. edodes.

Development of Low-Temperature Block Type Facility for Sea Water Desalination

This work is devoted to the fresh water deficit analysis. The importance of the research concerning water treatment is emphasized. A comparative analysis of water demineralization traditional methods is given and prospects for low-temperature desalination methods are shown. The increase in the world interest to the research of the block freezing innovative technologies was established, the priority in which belongs to the authors of this work. The aim of the work is to improve the block freezing devices during their transferring to a continuous operation mode. Achievement of this aim lies in a proposed universal design of the apparatus, in which the processes of crystallization, separation and melting of ice are sequentially implemented. A module for a continuous seawater desalination facility was developed. The energy and operational advantages of the proposed method were described. The system modeling of this equipment was carried out. The target function of the modeling determined the key parameters of the process of the ice block gravitational separation — energy and salinity. It was proposed to correct the traditional calculation principles for the outflow in channels by the “capillary drag” coefficient, which takes into account the relief surface of the ice capillaries. A technique for the engineering calculation of ice block salinity during separation was offered. The most significant result of the work lied in the fact of possibility to transfer the block freezing facilities to the continuous mode of sea water desalination with guaranteed salinity indicators. The significance of the work was that an energy-efficient freezing facility with ice recycling for the sea water demineralization in the flow was created.

Novel Crosslinked Sulfonated PVA/PEO Doped with Phosphated Titanium Oxide Nanotubes as Effective Green Cation Exchange Membrane for Direct Borohydride Fuel Cells.

A direct borohydride fuel cell (DBFC) is a type of low temperature fuel cell which requires efficient and low cost proton exchange membranes in order to commercialize it. Herein, a binary polymer blend was formulated from inexpensive and ecofriendly polymers, namely polyethylene oxide (PEO) and poly vinyl alcohol (PVA). Phosphated titanium oxide nanotube (PO4TiO2) was synthesized from a simple impregnation–calcination method and later embedded for the first time as a doping agent into this polymeric matrix with a percentage of 1–3 wt%. The membranes’ physicochemical properties such as oxidative stability and tensile strength were enhanced with increasing doping addition, while the borohydride permeability, water uptake, and swelling ratio of the membranes decreased with increasing PO4TiO2 weight percentage. However, the ionic conductivity and power density increased to 28 mS cm−1 and 72 mWcm−2 respectively for the membrane with 3 wt% of PO4TiO2 which achieved approximately 99% oxidative stability and 40.3 MPa tensile strength, better than Nafion117 (92% RW and 25 MPa). The fabricated membrane with the optimum properties (PVA/PEO/PO4TiO2-3) achieved higher selectivity than Nafion117 and could be efficient as a proton exchange membrane in the development of green and low cost DBFCs.

Development of effectively costed and performant novel cation exchange ceramic nanocomposite membrane based sulfonated PVA for direct borohydride fuel cells

A direct borohydride fuel cell (DBFC) is a type of low temperature fuel cell, and to commercialize this type of fuel cell, it requires efficient and inexpensive proton exchange membranes. In this study, a binary polymer blend is formulated from inexpensive and ecofriendly polymers such as iota carrageenan (IC) and polyvinyl alcohol (PVA). Zirconiam phosphate (ZrPO4) was synthesized from a simple impregnation — calcination method and later embedded as a doping agent into the polymeric matrix with percentage (1–7.5) wt.%. The novel nanocomposite membranes were evaluated by TGA, DSC, FTIR, XRD and SEM. The oxidative stability and tensile strength of the obtained membranes were enhanced and achieved results better than those of Nafion117 due to an increase in the number of hydrogen bonds formed between the polymer functional groups and oxygen functional groups of ZrPO4with increasing doping concentration. In addition, the borohydride permeability of the membranes decreased with increasing ZrPO4weight percentage, while the ionic conductivity and power density increased to 25.5 mS cm−1 and 66 mW cm−2, respectively, for membrane with 5 wt.% of ZrPO4. The fabricated membrane with the optimum properties (PVA/IC/ZrPO4− 5) can be efficient as a proton exchange membrane towards the development of green and low cost DBFCs.

Optimal Estimation of Proton Exchange Membrane Fuel Cells Parameter Based on Coyote Optimization Algorithm

In recent years, the penetration of fuel cells in distribution systems is significantly increased worldwide. The fuel cell is considered an electrochemical energy conversion component. It has the ability to convert chemical to electrical energies as well as heat. The proton exchange membrane (PEM) fuel cell uses hydrogen and oxygen as fuel. It is a low-temperature type that uses a noble metal catalyst, such as platinum, at reaction sites. The optimal modeling of PEM fuel cells improves the cell performance in different applications of the smart microgrid. Extracting the optimal parameters of the model can be achieved using an efficient optimization technique. In this line, this paper proposes a novel swarm-based algorithm called coyote optimization algorithm (COA) for finding the optimal parameter of PEM fuel cell as well as PEM stack. The sum of square deviation between measured voltages and the optimal estimated voltages obtained from the COA algorithm is minimized. Two practical PEM fuel cells including 250 W stack and Ned Stack PS6 are modeled to validate the capability of the proposed algorithm under different operating conditions. The effectiveness of the proposed COA is demonstrated through the comparison with four optimizers considering the same conditions. The final estimated results and statistical analysis show a significant accuracy of the proposed method. These results emphasize the ability of COA to estimate the parameters of the PEM fuel cell model more precisely.

The design and optimization of a cryogenic compressed hydrogen refueling process

Cryo-compressed hydrogen storage has excellent volume and mass hydrogen storage density, which is the most likely way to meet the storage requirements proposed by United States Department of Energy（DOE）. This paper contributes to propose and analyze a new cryogenic compressed hydrogen refueling station. The new type of low temperature and high-pressure hydrogenation station system can effectively reduce the problems such as too high liquefaction work when using liquid hydrogen as the gas source, the need to heat and regenerate to release hydrogen, and the damage of thermal stress on the storage tank during the filling process, so as to reduce the release of hydrogen and ensure the non-destructive filling of hydrogen. This paper focuses on the study of precooling process in filling. By establishing a heat transfer model, the dynamic trend of tank temperature with time in the precooling process of low-temperature and high-pressure hydrogen storage tank under constant pressure is studied. Two analysis methods are used to provide theoretical basis for the selection of inlet diameter of hydrogen storage tank. Through comparative analysis of the advantages and disadvantages of the two analysis methods, it is concluded that the analysis method of constant mass flow is more suitable for the selection in practical applications. According to it, the recommended diameter of the storage tank at the initial temperature of 300 K, 200 K and 100 K is selected, which are all 15 mm. It is further proved that the calculation method can meet the different storage tank states of hydrogen fuel cell vehicles when selecting the pipe diameter.

Comparison of effect of shot-peening with HFMI treatment or use of LTT consumables on fatigue strength of 1300\xa0MPa yield strength steel weldments

In this paper, T-joint samples in a 1300 MPa yield strength steel were produced using conventional or low transformation temperature (LTT) type consumables. The welded samples were either subjected to high-frequency mechanical impact (HFMI) treatment or to shot-peening. Fatigue testing was performed under fully reversed, constant amplitude bending load. Shot-peening gave a significant increase in fatigue strength for more than around 50,000 cycles. Shot-peened LTT welds had the highest fatigue strength, with conventional welds being shot-peened having slightly lower fatigue strength. HFMI treatment of conventional and LTT welds improved the fatigue strength also, but to a lesser extent, keeping the slope in the SN diagram close to three, while shot-peened samples had a slope of 5–7. Significant differences in compressive residual stress were seen between the different welds, with the most compressive stress found in the shot-peened samples. This was probably one of the main reasons for the improved fatigue life of shot-peened samples.

Downsized-Boosted Gasoline Engine with Exhaust Compound and Dilute Advanced Combustion

<div class="section abstract"><div class="htmlview paragraph">This article presents experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5: 1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expanded.</div><div class="htmlview paragraph">The main goal of this work is to implement in this engine, advanced lean/dilute low-temperature combustion for low-NOx and high efficiency operation, and to address the transition between the different operating modes. Those include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion at higher loads, before transitioning to boosted homogenous and stochiometric spark-ignited combustion. Here, the mixed-mode combustion strategy is composed of a deflagration of a stratified mixture created by a late direct injection, then triggering a controlled autoignition of the surrounding gas, improving the robustness of lean/dilute combustion. The paper describes the key features of the engine and details regarding the combustion and multi-mode valve strategies.</div><div class="htmlview paragraph">The experiments were performed under steady-state operation at 2000 rpm, from 1 to 11 bar IMEPn and naturally aspirated conditions. The engine demonstrated great efficiency gains compared to a conventional naturally-aspirated and downsized-boosted spark-ignited engines. The piston-compounding exhaust-heat recovery system contributes to up to 10% of the total efficiency improvement, while lean/dilute advanced combustion increases the fuel economy by up to 38% compared to a naturally aspirated engine, and up to 22%, compared to a downsized-boosted engine. NOx emissions target was met using high-levels of internal and external dilution in mixed-mode combustion operation, as well as by optimizing the injection and ignition strategy. Finally, the analysis shows that a seamless transition between the different valving strategies is achievable in support of robust transient operation.</div></div>

Zakarpatskiy perlit as component of mineral woven fabric material

Thanks to the peculiarities of the chemical composition and structure, perlite has received application for manufacturing building materials - thermal insulation and ceramic
 Results over of research of the silicate systems with transcarpathian perlite as raw material for making of mineral astringent material are driven. The features of the chemical-mineralogical composition, phase transformations during burning and astringent properties of material at the use of perlite from Beregovsky deposit in composition initial raw material mixtures are shown.
 To determine and optimize raw material stock at the production of mineral binder material of low-temperature roasting type of natural or romanticum, a computer program "RomanCem" was used.
 After burning with a maximum temperature of 1100°C, the test of the binder material from the investigated 3-component mixtures with Transcarpathian perlite is characterized by differences in phase composition and properties.
 When using for the manufacture of mineral binder material of low-temperature firing of a gypsum natural or romantic cement 3-component mixtures based on the limestone system - perlit - clay, the content of Transcarpathian perlite is possible from 4 to 22 mass. %.

Synthesis, Characterization, Optical and Transport Properties of BaSnO<SUB>3</SUB> Synthesized by Wet Chemical Route

Alkaline earth stannates have renewed attention as potential materials for gas sensing, transparent conducting oxides and ceramic capacitor applications. A noble wet chemical route is chosen to synthesize BaSnO3 powders having micron size grains. Problems related to uneven grains and poor densification in conventional solid state route have been overcome in the present method. X-ray diffraction data confirms the single phase formation without any secondary phase having cubic perovskite structure (S.G. Pm-3m). The estimated lattice parameter is ≈4.11933A and percentage density is ≈90%. The microstructure probed by scanning electron micrograph reveals almost homogeneously distributed particles having random shape with some porosity. Phonon modes in FT-IR and Raman spectra confirm the local symmetry distortion. The DC conductivity at 200°C approaches almost 2 × 10-2 (Ω-cm)-1, which is almost of the same order as that observed in perovskite based electronic conductors. DC and a.c. electrical conductivity of the material follow Mott’s variable range hopping at low temperature and Arrhenius type thermally activated process at elevated temperatures. Evidence of small polar on formation is also verified. Optical band gap estimated from absorption data is ≈2.94 very close to the reported value. Composition prepared through the noble wet chemical route has high electrical conduction and suitable for gas sensing applications.