High-temperature Source Research Articles

Visible Opacities of S-type Stars: The d 3Φ–a 3Δ Band System of ZrO

ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d 3Φ–a3Δ system (γ system) with v′≤4 and v″ ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list can be used to determine Zr abundances in S stars. We also correct the line strengths for the B 1Π–A 1Δ transition calculated in our previous work.

Thermodynamic analysis for definition of low-potential heat sources

This study presents a method for defining low-potential energy sources based on thermodynamic analysis. It defines low potential energy sources and presents the results of calculating temperature levels corresponding to the concept of a low potential energy source. A classification of energy sources by thermal level was carried out, including sources of cold, low-potential heat and cold at reduced temperatures, low-potential heat and cold at elevated temperatures, and high-temperature sources. The analysis demonstrates the correspondence between thermodynamic assessment and practical views of many researchers on low-potential energy sources. Conclusions about the influence of external factors on the temperature range for these sources are drawn. It is shown that factors affecting the range of low-potential temperatures include: the temperature potential of consumers, as a reference point for temperature, and the efficiency of local stations for converting heat into work or electricity. Narrowed assessment is presented based on optimal conditions for humans (22 °C), from −90 °C to 203 °C, and extended assessment based on limits of liquid water existence at atmospheric pressure and temperatures (0–100 °C) from −104 °C to 329 °C with an efficiency of heat conversion stations of 38 %.

Performance Evaluation of CO2 + SiCl4 Binary Mixture in Recompression Brayton Cycle for Warm Climates

This work demonstrates the potential of CO2 + SiCl4 binary mixture as a working fluid for power generation cycle. Recompression Brayton cycle configuration is considered due to its proven record of high performance for medium- to high-temperature sources. The objective of this study is to assess the thermodynamic performance of a recompression Brayton cycle using a CO2 + SiCl4 binary mixture as a working fluid, particularly under warm climate conditions. The cycle is simulated using the Peng–Robinson equation of state in Aspen Hysys (v11) software, and the model is validated by comparing VLE data against experimental data from the literature. The analysis involves the assessment of cycle’s thermal efficiency and exergy efficiency under warm climatic conditions, with a minimum cycle temperature of 40 °C. The results demonstrate a notable improvement in the cycle’s thermodynamic performance with CO2 + SiCl4 binary mixture compared to pure CO2. A small concentration (5%) of SiCl4 in CO2 increases the thermal efficiency of the cycle from 41.7% to 43.4%. Moreover, irreversibility losses in the cooler and the heat recovery unit are significantly lower with the CO2 + SiCl4 binary mixture than with pure CO2. This improvement enhances the overall exergy efficiency of the cycle, increasing it from 62.1% to 70.2%. The primary reason for this enhancement is the substantial reduction in irreversibility losses in both the cooler and the HTR. This study reveals that when using a CO2 + SiCl4 mixture, the concentration must be optimized to avoid condensation in the compressor, which can cause physical damage to the compressor blades and other components, as well as increase power input. This issue arises from the higher glide temperature of the mixture at increased SiCl4 concentrations and the limited heat recovery from the cycle.

High-Temperature Geothermal Source in the Northeastern Datong Basin, North China: Evidence from the Drilled Rhyolite

High-Temperature Geothermal Source in the Northeastern Datong Basin, North China: Evidence from the Drilled Rhyolite

Parametric investigation and scale testing on accelerated CO2 sequestration of cement-based materials by utilizing industrial waste heat

The increasing CO2 emissions from heavy industries have presented a growing threat to the global environment. The critical solution is to develop CO2 sequestration technologies, especially the fast speed CO2 fixation methods. In this study, the CO2 uptake performances of hydrated cement paste under various environment parameters coupling with high temperature were evaluated through accelerated carbonation experiments. The results show that high temperature is an effective way to improve CO2 sequestration efficiency, in which the waste heat accompanied by the emitted CO2 can be used as the source of high temperature. Based on this, appropriate vapor and liquid water addition during carbonation can further improve the CO2 sequestration performance of powder samples. Moreover, the hydration and carbonation products and the porosity before and after carbonation were evaluated, high temperature and vapor acceleration method facilitated aragonite generation and higher porosity reduction. Scale-up test of recycled aggregates on CO2 sequestration under optimum carbonation conditions was evaluated, and the results show the CO2 sequestration performance of recycled aggregates was stable in different input scales, which could sustain the CO2 sequestration amount of 80kg/t-cem.

Numerical investigation of thermal soak within engine bay using lattice Boltzmann method

A large amount of heat accumulates in the engine bay for a short time after the engine runs at high load and shuts down, that will lead to thermal damage and thermal fatigue caused by the temperature rise of some heat sensitive components. This paper uses an aero-thermal coupling approach to study the heat transfer problem in the engine bay of an SUV model under thermal soak conditions. Due to the transient characteristics of the heat transfer process, the natural transient CFD software developed based on the LBM method is used to study the engine bay heat transfer during the 400 s key-off soak process. The analysis reveals that convection and radiation are the main heat transfer modes in the early stage of hot immersion (0–120 s), and conduction only makes a significant contribution in contact with high temperature sources. The radiation and convection are the key contributors to heat transfer processes of engine bay during soak, but the efficiency of radiation heat transfer decreases with the increase of time, whereas the efficiency of convection heat transfer is not always reduced, it will increase and then decrease with the increase of time. The coupling method established can predict the thermal state in the engine bay well, and is in good agreement with the experimental results. The results show that the error in the engine coolant temperature is less than 1 °C, and the error in the temperature of the heat-sensitive components is less than 5 °C. Finally, the potential risks of thermal damage and thermal fatigue states were assessed, providing an important reference for the control design of cooling fan running time after key-off.

The Influence of the Fire Point on the Thermal Dynamic Disaster in the Goaf

A thermal dynamic disaster in the goaf is one of the most serious coal mine disasters formed by coal spontaneous combustion and gas interweaving. However, the influence of the high-temperature hidden fire source formed in the goaf on the evolution law of thermal dynamic disasters is not clear, and effective prevention and control measures cannot be taken. Therefore, this paper uses the experimental platform of thermal dynamic disaster in the goaf to study the influence of different fire point positions on the development of thermal dynamic disaster in the goaf through a similar simulation experiment of thermal dynamic disaster evolution in the goaf and analyzes the corresponding relationship between temperature and CO concentration in the upper corner. The results show that under different locations of heat source, the high-temperature heat source of coal spontaneous combustion migrates to the air leakage side with sufficient oxygen supply, and an oxygen-poor circle is formed near the ignition point. Under the action of air leakage flow, CH4 accumulates in the deep part of the goaf on the return air side. Due to the increase in coal, part of CH4 is produced, which leads to the increase in concentration of CH4 at the ignition point. Under the action of different heat sources, the changing trend of concentration of CO and temperature in the return air corner is the same, but the temperature change in the return air corner shows a lag compared with the change in the concentration of CO, so concentration monitoring of CO can reflect the evolution process of the fire field in the goaf more quickly than temperature monitoring.

Crystal field effects of Al doping on the Stark splitting and gain bandwidth of erbium doped silica fibers

In this study, erbium-doped silica fibers (EDFs) with different Al/Er ratios were prepared by high-temperature source combined with the modified chemical vapor deposition (MCVD) method. The effects of different Al/Er ratios on the gain performance of erbium-doped silica fiber amplifiers (EDFA) were investigated. The EDFA demonstrated in this paper achieves a maximum gain of 45 dB at 1560 nm when the signal power is −20 dB, while the bandwidth of 20 dB gain is up to 68 nm (1532∼1600 nm). Additionally, the effect of Al doping on the crystal field around the Er ion was analyzed and the Stark energy level distribution of the Er ions was further derived. Our approach offers a feasible solution for C + L band amplification from the perspective of Stark effect and crystal field analysis.

Source and fate of atmospheric iron supplied to the subarctic North Pacific traced by stable iron isotope ratios

The availability of dissolved iron (Fe) limits primary production over some regions of the surface ocean, especially in regions such as the subarctic North Pacific. In this work, we use Fe stable isotope ratios (δ56Fe) in bulk and size-fractionated marine aerosol particles and dissolved Fe of surface seawater in the subarctic North Pacific on Japanese GEOTRACES cruise GP02 (Summer 2017) as a tracer to clarify the relative contribution of combustion and natural Fe in both marine aerosol particles and surface seawater. The bulk aerosols collected in the coastal regions of both East Asia and western North Pacific have total δ56Fe values that are as low as −0.5 ‰ when compared to crustal (+0.1 ‰), with both the water-soluble phase and the fine particles even more fractionated (as low as −1.9 and −2.8 ‰, respectively). The negative correlation between the aerosol δ56Fe signatures and the enrichment factors of Fe and other elements dominated by anthropogenic sources (e.g., lead and cadmium) in these coastal regions indicates the presence of Fe emitted from high-temperature combustion sources, such as coal combustion and metal smelting. In these regions, combustion Fe accounts for 4–13 and 13–45 % of the total and water-soluble aerosol Fe, respectively. The results demonstrate that soluble aerosol Fe sourced from combustion Fe can be equivalent to that sourced from natural dust Fe in these coastal regions. By contrast, the aerosol particles in pelagic regions were near crustal δ56Fe in all particle size fractions, indicating the dominance of natural Fe and little to no combustion Fe. The relationships among the fractional Fe solubility, major ion concentration, Fe species, and δ56Fe indicate that the presence of combustion Fe is the dominant reason for the solubility increase in the coastal regions and that the atmospheric processing of mineral dust during transport is more important in the pelagic regions. The dissolved Fe of the surface seawater at 10 m depth had a consistently higher δ56Fe by up to +1.5 ‰ than that of the simultaneously collected water-soluble aerosol Fe. The pattern of the elevated δ56Fe in the surface seawater corresponds to decreasing Fe concentrations and can be approximated by Rayleigh fractionation; we attribute these elevated surface δ56Fe values to the effect of biological uptake. New Fe fluxes from both the atmosphere and deeper depths are limited at least in summer compared with the biological uptake in the open ocean of the subarctic North Pacific.

Temperature response and chemical reactions of energetic materials under thermal radiation and heat conduction

Thermal radiation from a high-temperature source is the primary cause of energetic material explosions. However, current research cannot meet the need to prevent thermal radiation-caused explosions. This paper proposes a novel numerical calculation model for temperature response and the chemical reaction of energetic materials under thermal radiation based on the physical mechanisms and evolution of the thermal effect during the chain explosion accident. This model is essential for rapidly evaluating the effect of thermal radiation in chain explosion accidents. The numerical model in this study efficiently obtained the thermal response of energetic materials under thermal radiation, as well as the critical conditions for energetic material explosion under thermal radiation. The results reveal that heat conduction is difficult to cause the explosion of ammonium nitrate, but thermal radiation can. The critical temperature of explosion for ammonium nitrate is 1668 K, the critical duration is 15.93 s, and the critical distance is 7.85 m. The temperature, duration, and radiation distance of the heat source are crucial factors that induce the ammonium nitrate explosion. Firefighters must cover and protect ammonium nitrate within 7200 s and 15.93 s, respectively, when the external heat flow absorbed by the material is 2.688 kW/m2 and 28 kW/m2. The model proposed in this paper can predict the effect of thermal radiation once the heat source parameters are known. Besides, combined with machine learning, the model can also predict the heat source parameters once the parameters of the thermal radiation effect are known. Compared with the current numerical models to evaluate the effect of thermal radiation, the numerical model presented in this paper can evaluate the effect of thermal radiation in engineering more efficiently and has broad application prospects.

Thermodynamic performance investigation of environmentally friendly working fluids in a geothermal integrated pumped thermal energy storage system

Abstract Among the available energy storage technologies, pumped thermal energy storage (PTES) is emerging as a potential solution for large-scale electrical energy storage with no geographical limitations and high roundtrip efficiencies. However, PTES requires a low-cost, high-temperature heat source to achieve reasonable roundtrip efficiencies. Moreover, organic Rankine cycle-based PTES systems require high-performance and environmentally friendly working fluids. In this study, the thermodynamic performance of a geothermal integrated PTES system using environmentally friendly working fluids is investigated. The mathematical model of the geothermal integrated PTES system is developed using the first and second laws of thermodynamics and implemented in Engineering Equation Solver (EES). With the developed model, the thermodynamic performance of the PTES system for different working fluids, including Butene, cyclopentane, iso-butane, R1233zd(E), R1234ze(Z), R1224yd(Z), HFO1336-mzz(Z), R365mfc, n-hexane, and n-pentane was investigated. For geothermal fluid outlet temperatures between 60°C and 120°C and geothermal fluid inlet and outlet temperature differences across the evaporator between 20°C and 60°C, the net power ratio i.e., the ratio of the electrical energy discharged to the electrical energy used to run the charging cycle, is between 0.25 and 1.40. This shows that the system has the potential to give back more than 100% of the electrical energy used during charging under certain conditions. High net power ratios are obtained for a combination of high source temperatures and low geothermal fluid inlet and outlet temperature differences.

An Analysis of Laser Welding Technology used for Joining Dissimilar Metals, Computational Parameters and Challenges

Welding particularly joining dissimilar metals is new technology. Laser welding is a challenging task and most essential and reliable method of joining dissimilar metal used in various industrial area. Out of the modern welding laser welding is gaining its popularity due to its various unique features. Laser welding, is modern method of joining similar or dissimilar parts metal/non-metal by laser beam of very high power, high temperature source. Very good control on input factors, very small heat affected zone, precise accurate welding joint and high speed are some attractive features of this technique. This technology gives more flexibility to design engineer. Various kind of lasers such as Nd:YAG, Co2 laser, Diode laser, disk laser m/c are used in welding of automobile, aerospace and ships. All concept of laser welding depends on the key-hole phenomena. It is a cavity formed by recoil pressure and energy absorption is due to high temperature multi reflection of laser rays. So this gives deep Penetration of weld joint. This paper shows various Challanges of dissimilar metal welding and technique to over come this. In our use study We are going to use dissimilar metal plates of 3.5 mm thick of 16MnCr5 and 316 SS. This metal jonts are used in production of automotive cylindrical part in large quantity.

Silicon Tetrachloride as innovative working fluid for high temperature Rankine cycles: Thermal Stability, material compatibility, and energy analysis

Silicon Tetrachloride (SiCl4) is proposed as a new potential working fluid for high-temperature Rankine Cycles. The capability to overcome the actual thermal stability limit of fluids commercially employed in the state-of-the-art Organic Rankine Cycles (ORC) is demonstrated by static thermal stability and material compatibility tests. Experimental static test proves its thermo-chemical stability with a conventional stainless-steel alloy (AISI 316L) up to 650 °C. A preliminary material compatibility analysis performed with optical microscope on the AISI 316L cylinder, after exposure of 300 h to SiCl4 at temperature higher than 550 °C, confirms the potentiality of this fluid when coupled with high-grade heat sources. A thermodynamic analysis has been carried out accounting for the effect of operating conditions on the axial turbine efficiency. A comparison with fluids adopted in medium–high temperature ORCs is performed, evidencing that the proposed fluid could achieve more than + 10 % points as thermal efficiency gain compared to any commercial solutions when coupled with high-temperature sources such as solar, biomass, waste heat from industrial processes and prime movers. A 2 MW SiCl4 cycle operating full-electric at 550 °C reaches a thermal efficiency of 38 %, exceeding values attainable by any other working fluid under similar conditions and power size.

Integrated approach for simultaneously measuring thermophysical parameters of semi-transparent materials

To concurrently determine the thermophysical parameters of semi-transparent materials, a novel, to the best of our knowledge, integrated approach for concurrent measurement is proposed. In the measurement setup, a high-temperature radiation source and a beam reducer are employed to minimize the influence of background radiation. In order to differentiate between the transmitted and emitted radiation in the detection signal, the radiation signals from the radiation source are measured under four different conditions, enabling the calculation of transmissivity, emissivity, and reflectivity. The reliability and accuracy of the measurement method are validated by the thermophysical parameters of sapphire, and the results demonstrate a strong agreement between the measured data and previous findings. The combined uncertainties of transmissivity and emissivity for the sapphire at 753 K are estimated, highlighting the novel contribution of this method in investigating the thermophysical parameters of semi-transparent materials.

Harness High-Temperature Thermal Energy via Elastic Thermoelectric Aerogels

HighlightsA thermoelectric aerogel of highly elastic, flame-retardant and high-temperature-resistant PEDOT:PSS/SWCNT composite is fabricated.The assembled thermoelectric generator generates a maximum output power of 400 μW at a temperature difference of 300 K.The self-powered wearable sensing glove can achieve wide-range temperature detection, complex hand motion recognition and high-temperature warning.The intelligent fire warning system enables highly sensitive and repeatable monitoring and alarm capabilities for high-temperature fire sources.

Screening of organic lithium precursors for producing high-performance Li4SiO4-based thermochemical energy storage materials: Experimental and kinetic investigations

Thermochemical energy storage by using Li4SiO4 TCES materials has been considered a promising technology for efficient heat storage from high temperature sources (700–900 °C). It has been proven the utilization of organic lithium precursors could effectively improve the heat storage performance of derived Li4SiO4. Hence, in this work, 7 kinds of unreported organic lithium precursors were screened for producing high-performance Li4SiO4 TCES materials. The physicochemical properties, CO2 ad-desorption capacities and the heat storage/releasing performance of as-prepared Li4SiO4 were systematically evaluated by a series of experimental and kinetic investigations, and a dual modification effects of organic lithium precursor were revealed. As a consequence, 3 potential candidates including lithium benzoate, lithium oxalate and lithium citrate were screened out. Li4SiO4 adsorbents derived from these precursors show great heat storage amount promotions of over 50 % in comparison with the average capacity of traditional Li4SiO4 (~ 350 kJ/kg/cycle). Especially, the lithium citrate derived Li4SiO4 exhibits the greatest CO2 adsorption capacity, reaction rate and cyclic stability, leading to a cumulative storage amount of 5.9 MJ/kg within 10 cyclic heat storage/releasing processes. Above findings could provide guidance for the future development of high-performance Li4SiO4 materials and Li4SiO4-CO2 TCES systems.

LATE ARCHEAN SHELF-TO-BASIN IRON SHUTTLE CONTRIBUTES TO THE FORMATION OF THE WORLD-CLASS DATAIGOU BANDED IRON FORMATION

Abstract Banded iron formations (BIFs) are among the few chemical sedimentary archives that capture the biogeo-chemical evolution of Fe cycling and the redox evolution of the early Earth. Although biologically recycled continental Fe has been previously proposed to be a significant source of Fe in BIFs deposited from a stratified ocean at the onset of the Great Oxidation Event (GOE; ~2.5–2.2 Ga), constraining Fe sources and pathways in Archean BIFs remains challenging. Here we present major and trace element and Fe-Nd-Cr isotope data for the largest BIF (i.e., Dataigou) in China to test whether a benthic Fe shuttle was operative during deposition of pre-GOE BIFs. The absence of true, shale-normalized Ce anomalies, coupled with unfractionated Cr and positive Fe isotope compositions, suggests that BIF deposition occurred in an anoxic water column under reducing atmospheric conditions, whereas positive Eu anomalies indicate a significant input from a high-temperature hydrothermal source. Based on a significant correlation between initial Nd and Fe isotope data, we suggest that two Fe sources were periodically mixed and resulted in deposition of the Dataigou BIF. Here, we suggest the following sources: (1) hydrothermal fluids from sea-floor systems (low εNd(t) and high δ56Fe), derived from the interaction of fluids with underlying, older continental crust, and (2) a benthic Fe flux (high εNd(t) and low δ56Fe), generated by microbial Fe(III) reduction in coastal sediments during weathering of a nearby depleted landmass. Results presented here confirm, for the first time, that a microbially driven Fe shuttle was operational and supplied Fe on a basin-wide scale in the absence of atmospheric oxygen.

Waste heat recovery from the biomass engine for effective power generation using a new array-based system

Thermoelectric generator (TEG)-thermosyphon-based heat recovery system (HRS) for harvesting the heat from the high temperature sources is a well-known technology for power generation. However, various thermal resistances (a total of nine) are involved in the thermosyphon-based HRS between the heat sources and TEGs which generate irreversibility that ultimately reduces its performance. In this work, a new design of HRS i.e. TEG-array-based is proposed for effective power generation even at low temperatures of sustainable heat source by minimizing the thermal resistances. This TEG-array-based HRS is driven by a salt gradient thermal storage device (SGTSD) which is used for efficiently recovering and storing of sustainable waste heat generated from a biomass(renewable energy)-based engine-generator. The proposed system is experimentally studied to analyse the temperature variations in SGTSD, characteristics of sustainable waste heat temperature, and performance features of TEGs in terms of obtained electrical parameters, output power and conversion efficiency. The experimental results showed that the maximum open circuit voltage, output power and conversion efficiency of TEG are obtained as 81.62V, 7.438W and 4.63\\% respectively. With this proposed system, seven thermal resistances (out of total nine) are totally eliminated while the others two are lowered that leads to effectively transfer the energy from sustainable heat source to TEGs via minor equivalent thermal resistance of 0.01198oC/W. The proposed system is found to be capable of charging a 12 V, 80 Ah heavy-duty battery for real life applications.

Sustainability in anticancer drugs development

Cancer remains one of the most fatal disease threats to mankind. As the development of healthcare and medical science it is important to come up with a sustainable solution to deal with cancer treatment. Despite the fact that many of the approved drugs still exhibit high systemic toxicity, primarily as a result of their lack of tumor selectivity and current pharmacokinetic drawbacks (such as low water solubility), which adversely affect drug circulation time and bioavailability, anticancer research has produced impressive results in recent decades. The sensitivity of anticancer medications to various parameters has been proven by stability tests, which were conducted under gentle settings during their formation or during stressful exposure to high temperature, hydrolytic media, or light source. Because of this, the development of degradation products is evaluated in pharmaceutical formulations as well as in hospital waste released into the environment. Many formulations have been created to date with the goals of enhancing medication stability, lowering hazardous side effects, and attaining tissue-specific drug targeting. In targeted cancer therapy, the creation of prodrugs offers a viable approach to enhancing the stability, effectiveness, and selectivity of active ingredients. According to recent research, anticancer medications can be made more soluble, stable, and pharmacokinetic by incorporating them into vesicular systems like polymeric micelles or cyclodextrins or by using nanocarriers containing chemotherapeutics that bind to monoclonal antibodies. In this work, we provide an overview of the most recent developments in our understanding of the creation of potent, very stable anticancer medications that are either encapsulated in nanosystems or designed as stable prodrugs.

PROCESSING OF LIQUID HIGH-ENERGY PRODUCTS WITH THE PRODUCTION OF GAS MIXTURES OF A GIVEN COMPOSITION

The article considers the problem of using waste as an energy resource. The possibility of processing liquid carbon-containing waste, which is formed during the processing of agricultural products, the use of fats in the food industry and oils in transport, is analyzed. An analysis of the volumes of such waste is presented. It is shown that sunflower processing is accompanied by the formation of about 7,000 tons/year of liquid carbon-containing waste. Technological processes of food industry generate about 1,000 tons of such waste per year. A significant source of waste generation is motor vehicle companies, the total resource of which for the introduction of competitive processing technology is currently about 100,000 tons of olives. A promising resource source for the proposed technology is the process of thermal destruction of used automobile tires, of which 250–300 thousand tons are generated annually in Ukraine. Possibilities of introducing the technology of thermal decomposition of liquid carbon-containing substances of various origins, as components of waste, to create gaseous products of a given composition with further use in the chemical industry and replacement of natural gas are considered. The thermal decomposition of hydrocarbons with stabilization of the process due to the introduction of a high-temperature plasma discharge source into it is among the most promising methods of performing such a task. The results of the development of the methodology for the analytical study of the composition of gaseous fuels are presented. The concept and schematic diagram of the experimental stand are presented. The results of test studies are presented. Bibl. 15, Fig. 5, Tabl. 5.