Thermal Source Research Articles

An adapted hourly Himawari-8 fire product for China: principle, methodology and verification

Abstract. Wildfires exert strong influences on the environment, ecology, economy and public security. However, the existing hourly Himawari-8 fire product produced by the Japan Meteorological Agency (JMA) presents large uncertainties and is not suitable for reliable real-time fire monitoring in China. To fill this gap, the National Satellite Meteorological Center (NSMC) proposed an adaptive hourly Himawari-8 fire product for China based on the original Himawari-8 source by employing a dynamical threshold for fire extraction and a database of ground thermal sources. According to the visually extracted reference and consistency check, we found that the NSMC-Himawari-8 fire product effectively removed a majority of false fire alarms included in the original Himawari-8 fire product. Based on a rare field-collected ground reference dataset, we evaluated the reliability of original Himawari-8 and NSMC-Himawari-8 fire products across China. The overall accuracy of the raw Himawari-8 fire product was 54 % and 59 % (not considering the omission errors), respectively. As a comparison, by identifying more real fire pixels and avoiding a majority of false fire alarms, the overall accuracy of the NSMC-Himawari-8 fire product was 80 % and 84 % (not considering the omission errors), respectively, making it an ideal source for improved real-time fire monitoring across China. This research also provides a useful reference for employing a local dataset of underlying surfaces and thermal sources to enhance the accuracy of global fire products in specific regions. The NSMC-Himawari-8 fire product can be downloaded at http://figshare.com (last access: 17 April 2023) with the following DOI: https://doi.org/10.6084/m9.figshare.21550248 (Chen et al., 2022a).

Geothermal energy integrated multi-effect evaporator (MEE) and multi-effect distillation (MED)-based desalination systems: an ecofriendly and sustainable solutions.

Desalination is a tried-and-true method for obtaining clean water from the ocean's brackish waters and recycling and reusing water. It requires a fair amount of energy, so it is necessary to create sustainable energy systems to lessen energy use and environmental impact. For thermal desalination procedures, thermal sources can be great heat sources. This paper's research focuses on thermoeconomically optimized multi-effect distillation and geothermal desalination systems. Collecting hot water from subsurface reservoirs is a well-established method of generating electricity through geothermal sources. Low-temperature geothermal sources, which have a temperature of less than 130°C, can be utilized for thermal desalination systems, for example, multi-effect distillation (MED). Geothermal desalination is affordable, and it is possible to produce power simultaneously. Because it only uses clean, renewable energy and produces no greenhouse gasses or other pollutants, it is also safe for the environment. The viability of any geothermal desalination plant will be influenced by the location of the geothermal resource, feed water supply, cooling water source, water market, and concentrate disposal site. Geothermal energy can directly supply heat for a thermal desalination system or indirectly give electrical power to reverse the osmosis (RO) membrane-based desalination plant.

The unified impact of thermal radiation and heat source on unsteady flow of tangent hyperbolic nanofluid through a permeable shrinking sheet

The tangent hyperbolic nanofluid behaviour is observed in multiple practical applications and extensively used in different laboratory experiments. It motivates to focus on the two-dimensional boundary layer flow of tangent hyperbolic nanofluid past a shrinking sheet. The goal of this article is to scrutinize the mass and heat transport of an unsteady flow of non-Newtonian tangent hyperbolic nanofluid past a shrinking surface under the influences of a source of heat, thermal radiation and chemical reaction. The flow model is mathematically framed through a coupled nonlinear partial differential equations. To transform the non-linear PDEs to ODEs, we use the similarity transformations and reduced ODEs are solved by RK-IV (Runge-Kutta method of order four) with shooting technique using the computational software MATHEMATICA. The novelty which emerges from the flow pattern lies in the fact that there exist dual solutions for certain parametric domain and the range of the existing solution may be expanded by increasing the power-law index (n) and shortened by increasing the Weissenberg number (We). Another remarkable conclusion which can be drawn from the temporal stability analysis that among these two solutions, first solution is stable and realistic whereas the second solution is not physically realistic. A diversity of the parameter estimates were used to provide solution for velocity f′(η), temperature θ(η) and concentration profiles ϕ(η) of this fluid model. In addition to the above findings, there are graphs and tables with explanation for the skin friction coefficient, the Nusselt number and the Sherwood number. These characteristics of a tangent hyperbolic nanofluid are not reported yet and may be useful in the development of existing technology.

Comparative Numerical Study on the Weakening Effects of Microwave Irradiation and Surface Flux Heating Pretreatments in Comminution of Granite

Thermal pretreatments of rock, such as conventional heating and microwave irradiation, have received considerable attention recently as a viable method of improving the energy efficiency of mining processes that involve rock fracturing. This study presents a numerical analysis of the effects of thermal shock and microwave heating on the mechanical properties of hard, granite-like rock. More specifically, the aim is to numerically assess the reduction of uniaxial compressive strength of thermally pretreated specimens compared to intact ones. We also compare the performance of these two pretreatments (conventional heating and microwave irradiation) in terms of consumed energy and induced damage. Rock fracture is modelled by a damage-viscoplasticity model, with separate damage variables in tension and compression. A global solution strategy is developed for solving the thermo-mechanical problem (conventional heating) and the electromagnetic–thermo-mechanical problem (microwave heating). The electromagnetic part of the microwave heating problem is solved in COMSOL Multiphysics software Version 6.1 first. The electromagnetic solution is used as an input for the thermo-mechanical problem, which is finally solved by means of a staggered explicit solution method. Due to the predominance of the external thermal sources, the thermal and the mechanical parts of the problem in both cases are considered as uncoupled. Three-dimensional finite element simulations are utilized to study the damage-viscoplasticity model. An ore-shaped three-mineral numerical rock specimen is used in uniaxial compression tests.

Carnot Battery Based on Brayton Supercritical CO2 Thermal Machines Using Concentrated Solar Thermal Energy as a Low-Temperature Source

Carnot batteries store surplus power as heat. They consist of a heat pump, which upgrades a low-temperature thermal energy storage, a high-temperature storage system for the upgraded thermal energy, and a heat engine that converts the stored high-temperature thermal energy into power. A Carnot battery is proposed based on supercritical CO2 Brayton thermodynamic cycles. The low-temperature storage is a two-tank molten salt system at 380 °C/290 °C fed by a field of parabolic trough collectors. The high-temperature storage consists of another two-tank molten salt system at 589 °C/405 °C. Printed circuit heat exchangers would be required to withstand the high pressure of the cycles, but shell and tube heat exchangers are proposed instead to avoid clogging issues with molten salts. The conventional allocation of high-temperature molten salt heat exchangers is then modified. Using solar energy to enhance the low-temperature thermal source allowed a round-trip efficiency of 1.15 (COP of 2.46 and heat engine efficiency of 46.5%), thus increasing the stored power. The basic configuration has a levelised cost of storage of USD 376/MWh while replacing the shell and tube heat exchangers with hybrid printed circuit heat exchangers is expected to lower the cost to USD 188/MWh.

AB-452672-4 POINT-BY-POINT PULSED FIELD ABLATION USING A MULTIMODALITY GENERATOR: COMPARISON WITH RADIOFREQUENCY ABLATION IN REMAPPED CHRONIC SWINE HEARTS.

In recent years, Pulsed Field Ablation (PFA) has emerged as a novel non thermal energy source for ablation. To compare lesion durability and collateral damage between unipolar/biphasic PFA and RF delivered through a contact-force sensing catheter both in a point-by-point fashion. A 4 arm pre-clinical study (n=12 swine) was designed with the multimodality generator TRUPULSE™ 2. PFA was delivered with nominal dose (12 pulses) in Group 1 whereas a high PFA dose (24 pulses) was used to evaluate energy safety in Group 2. RF arms served as controls with energy deployed through multimodality (Group 3) or market available (Group 4) generators. A contact-force catheter was used to focally deliver PFA/RF at the right superior pulmonary vein (RSPV), left atrial posterior wall (LAPW) and Roof, mitral isthmus (MI), cavotricuspid Isthmus (CTI), and RA posterior wall (RAPW). Average contact force was 12.7±3.7g. Animals were remapped at immediate post and 28 days post ablation. All animals were euthanized at 28 days and gross necropsy and histology followed. Acute RSPV isolation was achieved in all animals (Figure 1). At 28 days, remapping showed that RSPV isolation was maintained in all but one animal (Group 1) showing an electrical gap confirmed on histology. RAPW, CTI, MI (with exception of 2 animals, 1 in Group 2 and 1 in Group 3), and LAPW were maintained per histology as well. Differently from RF, both PFA arms had essentially similar histopathologic effect showing benign mature scar tissue repair with no necrosis nor inflammation (Figure 1). PFA applied to the RA lateral and posterior wall did elicit phrenic nerve response during ablation confirming ablations were done on the nerve. However, at 28 days remap, the nerve was stimulated and, in all animals, remained intact with no signs of damage on necropsy or histology. Representative samples were selected from the downstream/upstream organs including the brain, rete mirabile, heart, lungs, liver, esophagus, spleen, and kidneys, which showed no evidence of thrombo-embolic events. In swine models, point-by-point unipolar/biphasic PFA ablation showed durable PVI lesions acutely and at remapping without any sign of collateral damage after 28 days remap study. On histology, PFA lesions evolved with scar tissue without signs of necrosis nor inflammation. Further studies are needed to investigate the long-term safety and efficacy of this point-by-point PFA contact force sensing catheter.

Ultra-low-noise transimpedance amplifier in cryogenic STM for studying novel quantum states by measuring shot noise

An ultra-low-noise large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. Its transimpedance gain is as high as 1 GΩ, and its bandwidth is over 300 kHz, but its equivalent input noise current power spectral density is less than 4 (fA)2/Hz at 100 kHz. The low inherent noise for the CryoSTM-TIA is due to its special design: (1) its pre-amplifier is made of a pair of low-noise cryogenic high electron mobility transistors (HEMTs); (2) the noise generated by one HEMT is eliminated by a large capacitor; (3) the capacitance of the cable connected the gate of the other HEMT to the tip is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. The dc output voltage drift of the CryoSTM-TIA is very low, as 5 μV/°C. The apparatus can be used for measuring the scanning tunneling differential conductance spectra, especially the scanning tunneling shot noise spectra (STSNS) of quantum systems, even if the shot noise is very low. It provides a universal tool to study various novel quantum states by measuring STSNS, such as detecting the Majorana bound states.

Development of a High Min-Entropy Quantum Random Number Generator Based on Amplified Spontaneous Emission.

We present the theory, architecture, and performance characteristics of a quantum random number generator (QRNG) which operates in a PCI express form factor-compatible plug-and-play design. The QRNG relies on a thermal light source (in this case, amplified spontaneous emission), which exhibits photon bunching according to the Bose-Einstein (BE) statistics. We demonstrate that 98.7% of the unprocessed random bit stream min-entropy is traceable to the BE (quantum) signal. The classical component is then removed using a non-reuse shift-XOR protocol, and the final random numbers are generated at a 200 Mbps rate and shown to pass the statistical randomness test suites FIPS 140-2, Alphabit, SmallCrush, DIEHARD, and Rabbit of the TestU01 library.

MXene reconciles concurrent enhancement of thermal conductivity and mechanical robustness of SiC-based thermal energy storage composites

Latent heat thermal energy storage techniques based on phase change materials (PCMs) play a vital role in efficient and stable utilization of intermittent solar and thermal energy sources. However, low thermal conductivity and poor mechanical strength are daunting bottlenecks of traditional PCMs, inhibiting their wide applications. Here, we successfully enhance both thermal conductivity and mechanical robustness of porous SiC-based composite phase change materials (CPCMs) via doping MXene into SiC skeletons, which are superior to state-of-the-art ceramic CPCMs. The thermal conductivity of MXene-doped CPCMs achieves 15.21 ​W/(m·K) at a porosity of 72.9%, which is 25% higher than that of undoped counterparts. The underlying mechanism lies in that the oxide layer on the surface of MXene melts at a high temperature, filling the gap between SiC grains and optimizing the thermal transport path. Compared with virgin SiC skeletons, the flexural strength and compressive strength of MXene-doped skeletons are enhanced by 20% and 29%, respectively. This is because MXene removed from the oxide layer disperses in the ceramic matrix and improves the mechanical strength of the composite through pull-out, crack deflection and the change of fracture mode. Superior cycle stability and thermal shock resistance are also demonstrated. High thermal conductivity, robust mechanical strength, exceptional stability, and high solar absorptance enable prepared composites to realize high-performance dual-functional thermal and solar energy storage.

Efficient and Thermally Stable Wide Bandgap Perovskite Solar Cells by Dual‐Source Vacuum Deposition

AbstractWide bandgap perovskites are being widely studied in view of their potential applications in tandem devices and other semitransparent photovoltaics. Vacuum deposition of perovskite thin films is advantageous as it allows the fabrication of multilayer devices, fine control over thickness and purity, and it can be upscaled to meet production needs. However, the vacuum processing of multicomponent perovskites (typically used to achieve wide bandgaps) is not straightforward, because one needs to simultaneously control several thermal sources during the deposition. Here a simplified dual‐source vacuum deposition method to obtain wide bandgap perovskite films is shown. The solar cells obtained with these materials have similar or even larger efficiency as those including multiple A‐cations, but are much more thermally stable, up to 3500 h at 85 °C for a perovskite with a bandgap of 1.64 eV. With optimized thickness, record efficiency of >19% and semitransparent devices with stabilized power output in excess of 17% are achieved.

Microwave Soldering of Low-Resistance Conductive Joints-Technical and Economic Aspects.

Soldering processes are applied in the fabrication of electronic circuits used in most modern domestic and industrial technologies. This article aims to introduce a new soldering technology based on the microwave joining of copper materials used in electronic applications. The study was focused on microwave technology used as the thermal source for soldering. A simulation model of temperature distributions in copper plates with overall dimensions of 50 × 10 × 0.8 mm was developed in order to determine the necessary microwave power for soldering. For 270 °C simulated on the surface of copper plates, the microwave-injected power was determined to be 598.89 W. An experimental program for 600, 650, 700, and 750 W was set in order to achieve soldering of copper plates in less than 1 min. Soldered copper plates were subject to electrical resistance measurements being obtained with variations up to ±1.5% of the initial electrical resistance of the base materials. The quality of joints has also been analyzed through microscopy after the soldering process. In addition, mechanical properties were determined using a universal testing machine. The results have shown similar behavior of the samples layered with SAC on the one-side and double-side but also a significantly lower force before breaking for one-side-layered samples. An economic analysis was performed and the results obtained have shown that in terms of energy efficiency and total costs for microwave soldering compared with manual soldering, microwave soldering is cost-effective for industrial processing.

Ionization Efficiency Measurement and Optimization of a Thermal Ion Source for Radioisotope Electromagnetic Separation

An available supply of high-specific-activity radioisotopes was identified by the U.S. Department of Energy as a critical priority in the development and eventual deployment of next-generation medical diagnostic and cancer therapy tools. A radioisotope mass separator, located at the Missouri University Research Reactor Center, was developed to provide radioactive ion beams for the separation and production of high-specific-activity lanthanides used in radiopharmacology. Experiments characterizing the ionization efficiency of a thermal ion source supporting the production of high-specific-activity 153Sm are reported. With the goal of maximizing ion current while maintaining beam stability, experiments with the test ion source expand upon previously reported data from a titanium prototype ion source. Experimental results of various factors affecting ion source performance, such as diameter of the extraction orifice, ionizer geometry, ionizer temperature, and sample evaporation rate, are presented.

Large Baseline Optical Imaging Assisted by Single Photons and Linear Quantum Optics.

In this Letter, we show that by combining quantum metrology and networking tools, it is possible to extend the baseline of an interferometric optical telescope and thus improve diffraction-limited imaging of point source positions. The quantum interferometer is based on single-photon sources, linear optical circuits, and efficient photon number counters. Surprisingly, with thermal (stellar) sources of low photon number per mode and high transmission losses across the baseline, the detected photon probability distribution still retains a large amount of Fisher information about the source position, allowing for a significant improvement in the resolution of positioning point sources, on the order of 10 μas. Our proposal can be implemented with current technology. In particular, our proposal does not require experimental optical quantum memories.

Evaluation of process conditions for methane pyrolysis applying the triple thermal plasma system

Among various thermal plasma sources for CH4 pyrolysis, singular direct current (DC) thermal plasma has limited capacity, erosion, and efficiency. However, the triple thermal plasma system has been applied for nanomaterial synthesis and exhibited results overcoming these limitations. This study used the triple thermal plasma system to investigate the most suitable conditions for CH4 pyrolysis. CH4 conversion rate and selectivity of H2 and C2H2 were analyzed by varying the CH4 flow rate and quenching conditions at a fixed power supply of approximately 30 kW, and the specific energy requirement (SER) per 1 kg H2 was compared with that of previous works. The maximum conversion rate was 97% at 50 L/min of CH4, which is approximately 7% higher than earlier studies under conditions with similar process enthalpy. In addition, the conversion of CH4 to C2H2 and further to heavier hydrocarbons proceeded one order of magnitude faster than the reaction time expected by the gas-phase reaction. This result is attributed to the easy penetration of CH4 into the core region with the highest temperature and the strong interaction between the processing gas and graphite surface due to the arrangement of the torches in the triple plasma system. C2H2 selectivity was relatively high, while it was less affected by the increase in the quenching gas than generally expected. This finding was attributed to the naturally fast quenching rate without quenching gas due to the structure expanding from the first to the second graphite. While quenching can enhance selectivity by stabilizing the radicals as intermediates such as H2 or C2H2, it depressed the following reaction with dehydrogenation. Thus, the quenching conditions must be optimized. Finally, we demonstrated that the triple thermal plasma enhanced CH4 pyrolysis regarding H2 production efficiency.

A magnetized Maxwell nanofluid flow over a stratified stretching surface with Cattaneo-Christov double diffusion theory

During the last few decades, researchers have been increasingly interested in non-Newtonian fluid flows due to their practical applications. There is an increasing interest in non-Newtonian fluids due to the wide variety of applications in many disciplines, including biological sciences, geophysics, the chemical industry, and petroleum engineering. Plastics, polymers, pulps, food, fuels, and molten plastics are among the fluids that exhibit non-Newtonian properties. The three-dimensional MHD Maxwell fluid flow comprising gyrotactic microorganisms over a stretching surface is analytically examined in the present analysis. The influence of the magnetic field is applied normal to the direction of the fluid flow. Additionally, the significance of chemical reaction, thermal radiation, heat source, and activation energy are also considered. The Cattaneo-Christov heat and mass flux model has been employed to illustrate the energy and mass transmission in viscoelastic flow caused by the stretching sheet. The modeled equations are reformed into a dimensionless system of differential equations through similarity variables which are further semi-analytically solved through the homotopy analysis method. The nature of velocity, concentration, energy, and motile microorganisms’ profiles are graphically presented against the variation of distinct physical constraints. It has been noticed that the velocity of Maxwell fluid declines by the rising influence of Rayleigh number, mixed convection, relaxation factor, magnetic field, and buoyancy ratio constant. The consequence of fluid relaxation term drops the energy profile, while the consequences of velocity ratio factor and magnetic field augment the temperature field. Furthermore, the Nusselt number advances with the rising trend of thermal radiation and heat source, while reducing with the impact of the thermal stratification factor.

Experimental studies on LaNi4.25Al0.75 alloy for hydrogen and thermal energy storage applications

Reversible exothermic and endothermic reactions between metals/alloys and hydrogen gas provide great opportunity to utilize various thermal energy sources such as waste heat, industrial exhaust, and solar thermal energy. Metal hydrides with favourable properties to operate at medium temperature heat (about 150 °C) are limited, and studies on hydrides in this temperature range are scarce. Hence, the present study aims at experimental investigations on LaNi4.25Al0.75 alloy in the temperature range of 150 °C–200 °C. A novel cartridge type of reactor is employed to investigate the hydrogen storage characteristics and thermal storage performance of this alloy. LaNi4.25Al0.75 is found to have a hydrogen storage capacity of about 1.20 wt% at 10 bar and 25 °C. In addition, it can store a total thermal energy of 285.7 kJ.kgMH−1 and can deliver heat at an average rate of 287.5 W.kgMH−1 at an efficiency of 64.1%.

Performance Assessment of the Heat Recovery System of a 12 MW SOFC-Based Generator on Board a Cruise Ship through a 0D Model

The present work considers a 12 MW Solid Oxide Fuel Cell (SOFC) power plant integrated with a heat recovery system installed on board an LNG-fuelled cruise ship of about 175,000 gross tonnes and 345 m in length. The SOFC plant is fed by LNG and generates electrical power within an integrated power system configuration; additionally, it provides part of the thermal energy demand. A zero-dimensional (0D) Aspen Plus model has been built-up to simulate the SOFC power plant and to assess the performances of the proposed heat recovery system. The model has been validated by comparing the results obtained with data from the literature and commercial SOFC modules. The integrated system has been optimized in order to maximize steam production since it is the most requested thermal source on board. The main design outcome is that the steam produced is made by the recovered water from the SOFC exhaust by about 50–60%, thus reducing the onboard water storage or production. Additionally, results indicate that such an integrated system could save up to about 14.4% of LNG.

Ultrasonic sample introduction combined with flame assisted thermal ionization: Pretreatment-free direct mass spectrometry analysis for fraction collecting tubes of preparative liquid chromatography

Ultrasonic sample introduction combined with flame assisted thermal ionization mass spectrometry (USI-FATI-MS) was developed to monitor the fractions of preparative liquid chromatography. Recently, ultrasound-based sample introduction techniques have achieved great advance in the field of high-throughput analysis. However, it is still a challenge to directly apply these existing techniques to the analysis of macro volume samples (mL level). In this work, ultrasonic sample introduction combined with flame assisted thermal ionization was used for pretreatment-free direct mass spectrometry analysis of micro to macro volume samples (μL-mL level). Utilizing this unique design of ultrasonic sample introduction, liquid sample in the container can be quickly atomized to the gas phase without contact. Then, due to the flame assisted thermal ionization source, desolvation and ionization of the sample droplets will occur immediately. USI-FATI-MS has shown excellent sensitivity, repeatability and great compatibility to solvents and compounds with a wide range of polarity. As a proof of concept, USI-FATI-MS has been applied for rapid monitoring and identification of purified synthetic and natural products in fractions.

Hybrid nanofluid MHD motion towards an exponentially stretching/shrinking sheet with the effect of thermal radiation, heat source and viscous dissipation

Hybrid nanofluid MHD motion towards an exponentially stretching/shrinking sheet with the effect of thermal radiation, heat source and viscous dissipation

The geothermal magmatic system at the northern Rahat volcanic field, Saudi Arabia, revealed from 3D magnetotelluric inversion

Harrat Rahat (HR) volcanic field is one of the most prominent volcanic areas in western Saudi Arabia, as it is a promising site for geothermal energy. HR has been intensively studied from a geologic point of view. Detailed inspections distinguished 12 stages of volcanic eruption with characteristic volcanics and age intervals. The area is seismologically active and suffered a swarm of earthquake events in 1999. Magnetotelluric measurements were conducted across the northern HR for deep electrical imaging to provide a comprehensive image of the geothermal source and its impact on volcanic eruptions and seismicity. Acquisition sites (65 in total) provided a square grid with ∼5 km intervals. The recording at each site continued for 20 h on average and covered a broad band of frequencies from 1 mHz to 300 Hz. Phase tensor representations and the calculated skew angles indicated three-dimensional subsurface structures. 3D inversion was then carried out using a start model of half space with 100Ωm. The inverted model shows a main magma chamber with very low resistivities in its interior (3 Ωm). Protrusions branch upwards, or first laterally and then upwards, from the main magma reservoir. They represent magma pathways to the surface and account for various eruption locations and stages. The magma chamber is overlain by a continuous zone of higher resistivity (>500 Ωm) that depicts the cooled-down lava sheets. The tabulated and spatially mapped historical eruptions are projected on the results of the 3D MT inversion in the form of slices cut at various depths to obtain clues about the details observed in the model. The epicenters of the 1999 swarm showed no direct spatial matching with features of the inverted model. Similarly, the foci positions are concentrated in the subsurface away from the geothermal source. This confirms the model, as the epicenters usually exist at zones of faults and fractures in the crust, even if the source of stresses that induce seismicity originates away from them. The rocks near the thermal source are ductile and cannot be a source of an elastic rupture. We conclude that the thermal magma reservoir is shallow (10–25 Km), of a large spatial extent (∼1000 km2), impacts surface features and induces earthquake activities.