Heat Characteristics Research Articles

Optimizing the trajectory of deep brain stimulation leads reduces RF heating during MRI at 3 T: Characteristics and clinical translation.

Radiofrequency (RF) induced tissue heating around deep brain stimulation (DBS) leads is a well-known safety risk during magnetic resonance imaging (MRI), hindering routine protocols for patients. Known factors that contribute to variations in the magnitude of RF heating across patients include the implanted lead's trajectory and its orientation with respect to the MRI electric fields. Currently, there are no consistent requirements for surgically implanting the extracranial portion of the DBS lead. Recent studies have shown that incorporating concentric loops in the extracranial trajectory of the lead can reduce RF heating, but the optimal positioning of the loop is unknown. In this study, we evaluated RF heating of 77 unique lead trajectories to determine how different characteristics of the trajectory affect RF heating during MRI at 3 T. We performed phantom experiments with commercial DBS systems from two manufacturers to determine how consistently modifying the lead trajectory mitigates RF heating. We also presented the first surgical implementation of these modified trajectories in patients. Low-heating trajectories included small concentric loops near the surgical burr hole which were readily implemented during the surgical procedure; these trajectories generated nearly a 2-fold reduction in RF heating compared to unmodified trajectories.Clinical Relevance- Surgically modifying the DBS lead trajectory can be a cost-effective strategy for reducing RF-induced heating during MRI at 3 T.

Hybrid-timescale dispatch of heat and electricity integrated system considering dynamic heat flow

In the electricity and heat integrated energy system, the transmission speed of heat energy is much slower than that of electricity. While the ignorance of the dynamic characteristic of heat system during the dispatch process often fails to satisfy the heat load. To address this issue and further improve the flexibility of the system, a dynamic linear model of heat pipeline is proposed, and a hybrid-timescale optimal dispatch strategy is established in this paper. Firstly, based on the finite difference method, the partial differential equation of heat pipeline is converted into a linear equality constraint. Then, a hybrid-timescale optimal dispatch model is established. By considering different dynamic characteristics of heat and power system, the calculation of dynamic linear model and dispatching of devices of power and heat system are realized under three different timescales. Finally, by using MATLAB, the effectiveness of the proposed dynamic model is validated compared with the conventional steady-state model and measured data. A series of simulation results verify that the proposed hybrid-timescale optimal dispatch strategy considering dynamic model helps the system to increase the supply rate of the heat load by 100% and decrease the economic cost,CO2andNOxemission by 0.79%, 0.2%, and 18.9%, respectively.

Enhancing energy efficiency of chemical absorption-based CO2 capture process with advanced waste-heat recovery modules at a high capture rate

A commercial-ready amine-based CO2 capture process (CCP) restricts its potential for industrial deployment at a high capture rate to achieve a net-zero carbon target due to its energy-intensive nature. This study aims to enhance the energy efficiency of a monoethanolamine (MEA)-based CCP, operating at a 95% capture rate, by developing advanced process modules that utilize low-grade waste heat. To establish a foundation for designing cascade modules that can recover energy from all available waste heat, the waste heat characteristics were analyzed, and the feasibility of four single modules was explored to recover the latent heat in a stripped gas. Subsequently, this study comparatively investigated the equivalent electrical works of the two designed cascade modules combined with lean vapor compression (LVC). A techno-analysis indicated that cascade modules provided outstanding energy-saving performance ranging from 12.27% to 24.55%, with an average improvement of 50% over single modules. Although the cascade modules combined with LVC showed similar energy-saving performances, higher robustness for equivalence factor (EF) and more energy-savings were discovered in the electricity generation and direct heat supply strategies, respectively. Economic analysis indicated that advanced process modules were economically feasible, with a savings-to-investment ratio (SIR) exceeding 1. The SIR and payback period (PBP) depended on EF and electricity prices. Significantly, the cascade module for direct heat supply emerged as the most appropriate in terms of both economic viability and energy-saving efficiency in amine-based CCPs, particularly at a higher EF.

Numerical study on effects of nozzle hole spacing distance on steam submerged jet condensation from triangular holes spray nozzle

Steam-water direct contact condensation (DCC) is a phenomenon which is frequently found in the industrial sector due to its rapid and efficient heat and mass exchange rates. In this work, three dimensional numerical study of steam injection from triangular hole nozzles (with different holes pitch circle diameter, PCD = 6, 8,10 and 12 mm) into subcooled water tank has been carried out using Eulerian multiphase flow model along with realizable k-epsilon turbulence model. The thermal phase change model as User Defined Function (UDF) was employed in Fluent software for capturing submerged steam jet condensation. The simulation results were validated using experimental results as well as previously published numerical study and a fairly good agreement was observed. The effects of nozzle hole spacing distance on distributions of various thermal hydraulics parameters including velocity, pressure, temperature, heat and transfer characteristics have been studied. The axial distribution of the velocity, temperature, heat transfer coefficient and mass transfer computed at the centerline of the nozzle was found weaker than observed at the centerline of the nozzle holes. However, these distributions were not weak at nozzle centerline for nozzle with PCD 6 mm. The heat transfer coefficient has been found in the ranges of 1.75–2.3 MW/m2 K. The results reveal that the heat transfer coefficient for nozzle PCD 8 mm is higher than rate obtained for other nozzles. The rate of mass transfer at the holes centerlines has been found increasing with the holes PCD. The axial distribution of the mass transfer curve shifts downstream for nozzle with smaller PCD. Additionally, the mutual shielding effect of the jets weakens as holes PCD increases.

Experimental Study of New Antioxidant to Inhibit Spontaneous Combustion of Coal

ABSTRACT Free radicals and metal ions are key factors causing coal spontaneous combustion. In order to effectively suppress coal spontaneous combustion, experiments were conducted using luteolin as an inhibitor, luteolin is abbreviated as LUT. The influence of different concentrations of LUT on the spontaneous combustion heat characteristics of coal was tested using a C600 high-precision microcalorimeter, and the inhibition mechanism was inferred by FTIR. The experimental results show that LUT is an effective coal oxygen inhibitor, under the same action conditions, different concentrations of LUT can absorb heat to different degrees, delay the initial exothermic temperature of coal, prolong the heat absorption phase of coal. Compared with raw coal, 6 wt% LUT absorbs the most heat, the starting exothermic temperature is delayed by 46°C, and the activation energy is increased by 47.89 kJ/mol, the functional group -OH content decreased by 43.4%, -CH3 decreased by 32.1%, -CH2-decreased by 37.76%. Based on this, the mechanism of inhibition is inferred, LUT not only removes free radicals (ROO•) during the chain initiation stage and captures free radicals (•OH) in the reaction chain but also chelates metal ions to inhibit the catalytic effect of metal ions during the free radical reaction, which can play a dual role in preventing free radical generation and interrupting the free radical chain reaction. The results of the study can provide a novel, environmentally friendly and effective way to prevent the spontaneous combustion of coal.

Eco-economic performance and application potential of a novel dual-source heat pump heating system

Decarbonization of building heating is the key to carbon neutrality. Heat pumps have great potential to replace non-renewable heating devices, thus creating economic and renewable heating systems. To overcome the application challenges of conventional heat pumps (HP), a novel dual-source heat pump (DSHP) heating system and corresponding model are proposed and validated in this paper. Simulated by the validated experiment-based model, the performance of the DSHP heating system is numerically investigated by comparing with different systems in various regions. The results show that the DSHP system has higher seasonal performance factors and near-zero defrosting costs when compared to the conventional HP heating system in different regions, resulting in 1.88%–21.53% reductions in annual heating bills and carbon emissions. Compared to the gas boiler heating system, the DSHP system can achieve 20.64%–54.36% of annual heating bill savings and 14.39%–86.09% of annual carbon reductions in selected regions. The investigation of heating characteristics and eco-economic performance of the DSHP system in different regions provided important guiding significance for the DSHP in global application, and thus contributes to achieving bill-saving and low-carbon heating and sustainable development.

Quantification of Precipitation and Latent Heating Associated with Northern Hemisphere Winter Extratropical Cyclones Using the GPM KuPR

Abstract The four-dimensional characteristics of precipitation and latent heating associated with Northern Hemisphere winter extratropical cyclones (ETCs) are quantitatively analyzed using over 1000 ETCs observed by the Ku-band radar on board the Global Precipitation Measurement (GPM) Core Observatory. We find that the maximum precipitation amount is observed before the minimum central pressure of ETCs (developing stage), independent of the deepening ratio. A key finding is that a cyclone in the developing stage has two large precipitation areas with contrasting precipitation characteristics. One is observed on the forward-left side of ETCs, collocating with warm fronts (Area X). The other is identified on the right-hand side of the ETC center in association with the warm sector and cold fronts (Area Y). These areas become unclear in the mature stage and disappear in the decaying stage. Many stratiform precipitation pixels weaker than 5 mm h−1 compose the large precipitation amount in Area X, with a stratiform-to-total precipitation ratio of more than 90%. In contrast, intense convective precipitation pixels of over 20 mm h−1 are observed about 3 times more in Area Y than in Area X, resulting in a stratiform-to-total precipitation ratio of 65%–80%. The most intense precipitation around ETCs is observed in this area. A larger latent heating maximum at 3.5-km altitude and a higher near-surface cooling rate in Area X result in a higher vertical heating gradient compared to Area Y. The contrasting characteristics between the two areas are more pronounced in the rapidly developing ETCs. Significance Statement Statistical analyses are conducted to elucidate the four-dimensional structures of precipitation and latent heating associated with more than 1000 Northern Hemisphere winter extratropical cyclones using data observed by the Ku-band radar on board the Global Precipitation Measurement (GPM) Core Observatory. The horizontal precipitation composite at the developing stage of the cyclones shows two areas with large precipitation amounts. One is characterized by a large amount of weak stratiform precipitation, and a higher vertical heating gradient, collocating with warm fronts. The other is characterized by intense convective precipitation in association with the warm sector and cold fronts. The quantitative information on precipitation and latent heating obtained from the observation of many cyclones is valuable for the validation of numerical simulation results.

MONITORING PERFUSION-BASED CONVECTION IN CANCER TUMOR TISSUE UNDERGOING NANOPARTICLE HEATING BY ANALYZING TEMPERATURE RESPONSES TO TRANSIENT PULSED HEATING.

The dynamic nature of perfusion in living tissues, such as solid tumors during thermal therapy, produces challenging spatiotemporal thermal boundary conditions. Changes in perfusion can manifest as changes in convective heat transfer that influence temperature changes during cyclic heating. Herein, we propose a method to actively monitor changes in local convection (perfusion) in vivo by using a transient thermal pulsing analysis. Syngeneic 4T1 tumor cells were injected subcutaneously into BALB/c mice and followed by caliper measurements. When tumor volumes measured 150-400 mm3, mice were randomly divided into one of two groups to receive intratumor injections of one of two iron oxide nanoparticle formulations for pulsed heating with an alternating magnetic field (AMF). The nanoparticles differed in both heating characteristics and coating. Intratumor temperature near the injection site as well as rectal temperature were measured with an optic fiber temperature probe. Following heating, mice were euthanized and tumors harvested and prepared for histological evaluation of nanoparticle distribution. To ascertain the heat transfer coefficient from heating and cooling pulses, we fit a lumped capacitance, Box-Lucas model to the time-temperature data assuming fixed tumor geometry and constant experimental conditions. For the first particle set, the injected nanoparticles dispersed evenly throughout the tumor with minimal aggregation, and with minimal change in convection. On the other hand, heating with the second particle generated a measurable decline in convective performance and histology analysis showed substantial aggregation near the injection site. We consider it likely that though the second nanoparticle type produced less heating per unit mass, its tendency to aggregate led to more intense local heating and tissue damage. Further analysis and experimentation is warranted to establish quantitative correlations between measured temperature changes, perfusion, and tissue damage responses. Implementing this type of analysis may stimulate development of robust and adaptive temperature controllers for medical device applications.

A cleaner and more efficient energy system achieving a sustainable future for road transport

A novel integrated cooling system is developed for future medium to large electric vehicles by integrating the fuel cell, battery, metal-hydride, heat pump, and liquid desiccant dehumidification system to reduce power consumption and extend vehicle's driving range. The system benefits from the reuse of the normally wasted energy in the form of pressure difference and wasted thermal energy, from the hydrogen vessel, the fuel cell stack, and the battery pack. A numerical model for the proposed system and a finite element model for the dehumidifier and regenerator are developed and validated by experimental results from published data. A comprehensive evaluation of the impacts of the ambient air temperature and humidity, fuel cell current output, battery discharging C rate, and air mass flow rate on the Coefficient of Performance (COP), outlet air temperature, and cooling capacity is conducted. Two operating modes, namely non-compressive mode and heat pump supplemental mode are investigated and a detailed comparison between these two modes is undertaken. Furthermore, the proposed system under heat pump supplemental mode has been compared to other published cooling systems and dehumidification systems. Under non-compressive mode, results indicate that the proposed system can provide sufficient cooling capacity without the need of the compressor when the supply air mass flow rate is lower than 0.03 kg/s, under the specific operating situation. Under the heat pump supplemental mode, the proposed system can operate at 36 °C with a COP greater than 4, which is 56% higher than the cited published results, although the COP of the proposed system also considers battery cooling. Heat pump supplemental mode drastically reduces the 12-s insufficient cooling period that occurs at the beginning of the charging to discharging transition between the two metal hydrides to 2 s compared to non-compressed mode. Overall, this study provides a potential solution for future zero-emission vehicles by utilizing the heat and electric co-generation characteristic of the fuel cell, the isothermal characteristic of the metal hydride, and dehumidification and cooling characteristics of the liquid desiccant dehumidification system to extend the driving range of the electric vehicles and reduce energy consumption for cooling. Moreover, the proposed system can also provide domestic cooling loads and power by integrating the system into residential buildings.

Flexible Transparent Planar Heater Comprising ZnO/Cu/Al2O3

In this study, we fabricated transparent heaters composed of an ultrathin Cu-layer heating element sandwiched between a ZnO underlayer and an Al2O3 overlayer. With the Cu layer thickness fixed at 8.5 nm, the thicknesses of the ZnO and Al2O3 layers were independently varied to reach the optimum antireflecting condition (maximum transmittance of 88.3% and average visible light transmittance of 79.8% were achieved). The sheet resistances for the ZnO/Cu/Al2O3 heaters can be varied by simply modulating the Cu layer thicknesses. In order to assess the flexibility of the transparent heaters, we constructed a ZnO/Cu/Al2O3 structure on flexible polyimide substrates, and the thermal, electrical, optical and mechanical characteristics were evaluated. Because of the planar heating element of the Cu layer, the thermal response was found to be extremely high, i.e., less than 10 s were required to reach 90% of the target temperatures. Once the target temperatures were reached, the heater temperatures were highly stable with no degradation of electrical and optical properties. Furthermore, the heating capability was maintained under severe mechanical deformation, e.g., at a bending radius of 4 mm. The structure also exhibited highly sustainable optoelectronic properties under repetitive mechanical deformation, confirming the potential for commercialization. Finally, we demonstrated that ZnO/Cu/Al2O3 rolled around a human finger exhibited highly uniform heating characteristics, rendering the heaters suitable for wearable, healthcare electronics.

Photo-thermal conversion and Joule heat characteristics of thermal switch via carbon fiber-based composite

Photo-thermal conversion and Joule heat characteristics of thermal switch via carbon fiber-based composite

Effect of Nanographite Conductive Concrete Mixed with Magnetite Sand Excited by Different Alkali Activators and Their Combinations on the Properties of Conductive Concrete

In order to obtain conductive concrete with good electrical conductivity and good mechanical properties, nanographite and magnetite sand excited by different activators and their combinations are added to ordinary concrete to obtain high quality and efficient conductive concrete. The optimal mixture ratio of alkali-excited conductive concrete and the effects of different activators and their combinations on the mechanics and electrical conductivity of concrete were studied. The microstructure of alkali-excited conductive concrete was analyzed by scanning electron microscope (SEM) to study its conductive mechanism. Results show that the conductive concrete obtained by compounding sodium hydroxide, sodium sulfate and calcium hydroxide has optimal mechanical and electrical properties when the graphite is 6% cement, and magnetite sand is 40% fine aggregate. The conductive concrete sample prepared by this method has a flexural strength of 6.84 MPa, a compressive strength of 47.79 MPa and a resistivity of 4805 Ω·cm (28 days). Compared with ordinary concrete (no nanographite and no magnetite sand), the compressive strength of conductive concrete is increased by 122.3%, the bending strength is increased by 116.5%, and the resistivity is reduced by 99.1%. SEM shows that the distribution of conductive materials in concrete is more uniform due to alkali excitation and calcium silicate hydrate (CSH) gel can be formed, which leads to better performance. The research in this paper is only a preliminary exploration of the characteristics of green conductive concrete, and the conductive heating characteristics and electromagnetic wave absorption properties of concrete, along with strength characteristics after adding conductive fillers, need to be further studied. It is suggested that further research should be carried out on the deicing characteristics of conductive concrete and the electromagnetic wave absorption properties used in stealth military engineering.

Analysis on the Current Energy Consumption of Heating In Rural Toilets in Tibet

In order to grasp the basic sanitation facilities, toilet renovation planning and progress, residents' toilet habits and willingness to renovate, and the maintenance status of renovated toilets in townships and rural areas of Tibet, and to understand the basic situation and toilet renovation planning of public toilets in townships and rural areas. This article selects independent public toilets in agricultural and pastoral areas of Tibet as the research object. In response to the problems of low indoor temperature and high heat consumption in township toilets, the construction and heating status of township toilets were obtained through on-site research. The heating characteristics of township toilet buildings were summarized, and typical buildings were selected for load characteristics analysis, providing a preliminary basis for the design of solar heating schemes in the future.

Estimation of regional anthropogenic heat from air conditioning systems and related devices in metropolitan commercial districts of Japan

With the expanding urban areas and increasing elderly population in Japan, anthropogenic heat poses substantial threat to human health. Air conditioning systems contribute to the anthropogenic heat from buildings. However, information regarding the heat characteristics of these systems is inadequate. In the present study, we developed a method for estimating anthropogenic heat from air conditioning, which accounts for most of the artificial heat from buildings during summer, to include artificial anthropogenic heat from surrounding buildings in the local heat risk assessment. The estimation results for commercial areas in Japan using the developed method showed that latent heat from air conditioning is substantially higher than sensible heat, and there was a difference in heat emissions between daytime and nighttime and between weekdays and holidays. A comparison of the calculation results of our method and those of previous studies showed no major differences in the orders of magnitude. With regard to the change in the amount of air-conditioning anthropogenic heat in the region, a directly proportional relationship was found between the outdoor temperature and the amount of air-conditioning anthropogenic heat. These results are useful for assessing the summer heat risk in urban areas and developing methods to mitigate the risks posed by urban heat.

Математическое моделирование индивидуально-поточного движения людей из здания роддома при пожаре

Statistical data on the number of fires and people killed in fires in the Russian Federation for the period under review and on the objects of fires are presented. The basics of fire safety of maternity hospitals are considered. The fire safety assessment of the maternity hospital in question was carried out. The data on the fire protection system of the maternity hospital building, on the smoke protection and alarm systems used, on fire-fighting water supply, as well as information on the characteristics of electricity, heating and ventilation are given. Mathematical models used to calculate the evacuation time of people from the maternity hospital building in question are presented. The coordinate scheme of a possible variant of the placement of people who are at a given time on the evacuation routes is considered. The possible density of the flow of evacuating people in the stream within the considered evacuation area is analyzed. The basic calculation formulas used in the design of buildings, taking into account the organization of the movement of human flows, are given. The program used the Fogard complex, which implements an individual flow model developed on the basis of a mathematical model of the individual flow movement of people from the building. The developed evacuation plan of a typical floor was used as the initial data for the calculations. As a result, the main goal of the work was achieved, which is to analyze the movement of human flows and clarify the estimated time needed to rescue evacuees from the maternity hospital building.

Hydration kinetics analysis of cementitious paste composites produced by binary and ternary binder materials for potential use in massive concrete structures

In order to explore the applicability of different cementitious paste systems used for massive concrete structures, the hydration characteristics and mechanism of the binary and ternary cementitious paste systems in Portland cement pastes containing fly ash and slag were investigated in this work. The hydration heat release rate and cumulative heat release of each cementitious paste system at 20 ℃ and 60 ℃ were measured by an isothermal calorimeter. The characteristic parameters of each cementitious paste system hydration process were calculated and analyzed using the Knudsen equation and Krstulović-Dabić hydration kinetic model. Besides, the hydration mechanism was analyzed. It was obtained that the cement-fly ash (C-F) binary system is not effective in reducing the early reaction rate but its overall heat release is lower; while, the cement-slag (C-S) binary system is more effective in reducing the reaction rate but its overall heat release is higher, and the cement-fly ash-slag (C-F-S) ternary system has the advantages of both above binary systems. Probably, the C-F-S ternary system is more consistent with the heating characteristics of massive concrete structures, and it is more applicable. There are few studies on the hydration characteristics of C-F-S ternary systems from the perspective of hydration kinetic, and this work provides theoretical basis for the selection of cementitious paste systems for massive concrete structures.

Microwave heating of coal slime based on multi-physics field simulations: Regulating waveguide port size and sample radius to improve microwave utilization efficiency

Microwave pyrolysis, a promising green-processing technology with high efficiency and low consumption, is particularly applicable in the pyrolysis of solid waste fuels such as coal slime. The microwave thermal effect plays an imperative role in the pyrolysis process. Low microwave utilization efficiency in single-mode microwave cavities is caused by the irregular field intensity distribution, and since of the high manufacturing costs of the equipment, it is unclear the relationship between waveguide port size, microwave field intensity distribution, and the temperature of sample. In this study, the effects of different waveguide port sizes and sample radius on the heating characteristics of coal slime were investigated using COMSOL Multiphysics software to construct a coupled multiphysics finite-element model. Moreover, the effects of the radius of the coal slime on the microwave utilization efficiency. The results demonstrated that only two types of wave distribution were found within the cavity, α and β, under the size of the waveguide port. The field intensity distribution in the β-type cavity was uniform, which prompted the sample temperature from 176 °C to 657 °C and microwave utilization efficiency from 10.16 % to 33.87 %. The maximum microwave utilization efficiency was increased from 33.87 % to 67.22 % by adjusting the radius of the sample at the optimal port size. The efficiency of the microwaves was maximized when the width-to-height ratio of the waveguide is 70:65 and the sample radius is 30–35 mm, and the sample temperature was maintained in a more desirable range. From the findings of this study, both the waveguide port size and sample radius are essential influencing factors in determining the sample temperature and microwave energy utilization efficiency during the heating of coal slime.

Influence of current density on constant current electric field enhanced aluminum induced crystallization of amorphous silicon thin films

In this study, electric field-enhanced aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) thin films was investigated considering various current densities. Constant electric currents of 4, 5, and 6 A were applied to assess the Joule heating characteristics during specific durations (40, 15.5, and 9 s). The samples were prepared by depositing a 200-nm thick a-Si layer on a glass substrate and sputtering a 300-nm thick aluminum (Al) layer onto the a-Si layer. During the AIC process, layer exchange occured via the diffusion of silicon (Si) into the Al layer. This phenomenon was verified by the in-situ reflectivity, which was in excellent agreement with thin-film optics calculations. During the annealing, processing temperatures were lower than 470 °C, which is less than the Al-Si eutectic temperature of 577 °C. The Raman peak observed near a wavenumber of 519 cm−1 revealed the formation of polycrystalline silicon films through Joule heating processes. Field-effect scanning electron microscopy images were captured and analyzed to investigate the surface morphology of the samples, specifically focusing on grain growth.

Effect of silicon carbide powder on temperature field distribution characteristics and microwave deicing efficiency of cement concrete containing magnetite (Fe3O4) powder

To improve the temperature field distribution characteristics and overall deicing efficiency of magnetite (Fe3O4) powder concrete during microwave heating at the extremely low-temperature condition, the silicon carbide (SiC) powder with favorable heat transfer ability was added to the concrete system. The microwave heating characteristics and thermal conductivity of concrete were studied to analyze its heating rate and heat transfer ability, respectively. Meanwhile, the thermal response changes of the concrete surface were recorded during the microwave heating, and the temperature difference (TD) and standard deviation (St.d) were used to characterize its surface temperature field distribution characteristics. In addition, the ice layer shedding time (ILST) of the concrete surface was used to evaluate the overall deicing efficiency of the concrete coated with ice. The results showed that in the microwave-absorbing concrete, the Fe3O4 content was the main factor affecting its microwave heating rate. The SiC could effectively improve the thermal conductivity of concrete. When the SiC content was 6 wt%, the heat transfer ability of concrete was improved by 69.2%. Therefore, after adding the SiC, the temperature field distribution characteristics of the concrete surface were tending to be uniform during microwave heating. After heating 120 s, the SiC content with 6 wt% could effectively reduce the TD by 23 °C and the St.d by 5.6 °C of surface temperature field of concrete containing Fe3O4. When the mass percentage of Fe3O4 and SiC was 1:1, the ILST of concrete coated with ice was the shortest at the icing temperature of −30 °C and the ice layer thickness of 20 mm. It was 55.5 and 24.3 s shorter than that of concrete without absorbing materials and thermal conductivity materials, respectively, and its deicing efficiency was 1.51 and 1.22 times higher than theirs.

Study on the influence of constraint conditions on the slow cook-off response characteristics of melting and casting explosives

In order to study the slow cook-off test response characteristics of melt cast explosive and cast explosives under different constraint conditions, the heating characteristics, ignition characteristics and response law of melt cast B explosive and cast nitrate PBX explosive were studied by using self-designed slow cook-off test device when the ratio of discharge hole area to charge cross-section area Sh/Sc was 10%, 5% and 0%, respectively. The results show that in the slow cook-off process of two kinds of charge, the shell drain hole can effectively discharge gas or part of explosive before ignition. After ignition, the pressure can be released reliably, the increase of internal pressure in the shell can be restrained, and the intensity of response can be reduced; With the decrease of the size of the drain hole, the reaction intensity increases and the damage degree of the shell increases; When Sh /Sc =10, the combustion reaction takes place in both casting charge and casting charge; When Sh /Sc =5, the deflagration reaction occurs in the melt casting charge, which first burns and then deflagration reaction occurs in the casting charge; When Sh /Sc =0, the fusion charge and the casting charge have explosive reaction; Under the same constraint conditions, the safety of cast explosive is slightly higher than that of cast explosive.