Suitable Heating Research Articles

Electric heating curing regimes of temperature self-controlled concrete with nano-carbon black for performance improvement in cold regions

Temperature self-controlled concrete (TSC) demonstrates excellent electric heating performance, providing an effective solution for on-site curing of concrete in cold regions. A suitable electric heating curing (EHC) regime can lead to a desired internal temperature to facilitate the hydration of cement under negative temperature environment and improve the performance of concrete. This study prepared the TSC by adding nano-carbon black into ordinary concrete and investigated the effects of 2 different types of EHC regime, namely constant voltage curing (CVC) and ascending voltage curing (AVC) regimes, on the mechanical properties, electrical properties, temperature evolution, microstructure, and carbon emissions. The results demonstrate that samples cured using traditional methods exhibit the lowest strength. In contrast, the application of EHC shows significant advantages in negative environments compared to traditional curing methods. TSC cured under AVC regimes exhibits a 21.3 % and 33.4 % increase in compressive strength, as well as a 4.4 % and 20.8 % increase in splitting tensile strength at 3 days and 7 days, respectively, compared to TSC cured under CVC regimes. AVC effectively reduces peak temperature and temperature difference, and leads to the peak temperature shifting backward. Additionally, the hydration products of TSC cured under AVC regimes are fewer. However, AVC regimes promote stable microstructural development, favorable resistivity of TSC, and result in a lower carbon footprint during the curing period. The research findings highlight the superiority of AVC regimes in negative temperature environments, potentially addressing challenges in in-situ curing of concrete structures in cold regions and improving efficiency in prefabricated component production.

Selection of household heating equipment: A case study of Lianyungang city

Abstract Based on the local climate in Lianyungang, this paper analyzes the local heating demand, a comprehensive comparison of mainstream heating equipment and terminal forms, and analysis and discussion, respectively. By simulating the heating situation in Lianyungang in winter, the heating cost of different equipment in Lianyungang in winter is calculated and combined with the operation of existing projects, and the differences in cost, use, installation, and maintenance of different heating equipment are compared. Finally, the most suitable heating form for Lianyungang users is summarized by integrating theoretical data and actual situations.

Development of a Microwave-Assisted Bench Reactor for Biomass Pyrolysis Using Hybrid Heating.

Microwave-assisted pyrolysis (MAP) is a cutting-edge technology that converts biomass into fuels, chemicals, and materials. In this study, an Arduino was used to control and automate a MAP system built from a microwave oven with a cordierite chamber filled with silicon carbide. Sugar cane bagasse was pyrolyzed at 250, 350, 450, and 550 °C to validate the MAP system and obtain pyrolytic products with different yields and chemical compositions. Lower temperatures led to high biochar yields, but the highest surface area of 25.14 m2 g-1 was only achieved at 550 °C. By contrast, higher temperatures favored the recovery of pyrolysis liquids. BET and scanning electron microscopy analyses revealed a porous biochar structure, while Fourier transform infrared spectroscopy analysis showed that the availability of functional groups on the biochar surface decreased with an increase in pyrolysis temperature. GC-MS analysis quantified valuable low molecular mass compounds in pyrolysis liquids, including aldehydes, ketones, phenols, and alcohols. With its unprecedented hybrid heating device, the MAP system promoted suitable heating rates (31.9 °C min-1) and precise temperature control (only 19 °C of set point variation), generating pyrolysis products devoid of microwave susceptor interferences. Therefore, MAP provided a rapid, safe, and efficient means of depolymerizing biomass, thus holding promise for biorefinery applications.

Oleogels based on peanut protein isolate fibrils: Structural characterization dependent on induction time and suitability in marguerite biscuits

In order to develop new plant protein-based lipid substitutes to deal with health problems caused by animal fats or trans-fatty acids, the emulsion stablized by acid-heat (90 °C, pH 2.0) induced aggregation of peanut protein isolate (PPI) was used as template to fabricate oleogels. Heating time affected the structure, morphology of PPI and the adsorption characteristics at the O/W interface. The protein with suitable heating time (2–6 h) formed fibrils structure, which was beneficial to the rapid adsorption of aggregates at the O/W interface. Overheating (exceeding 8 h) led to the aggregate of protein fibrils and inhibited the adsorption of proteins at the O/W interface. Therefore, the heating times of 2 h, 4 h and 6 h were selected to prepare the follow-up emulsion and oleogels. Among the four heating times, the emulsion prepared by PPI heating for 6 h showed the best storage stability, ionic strength stability and shear resistance. The resultant oleogels exhibited the least oil loss and the highest freeze-thaw stability. The margarita biscuits prepared with a substitution rate of 50% oleogels to butter presented similar sensory property to the margaritas prepared with butter, indicating that the oleogels possessed favorable shortening properties. The results indicated that PPI fibrils structure could improve the oleogel formaton properties, making it a potential novel additive for the development of new fat substitute products.

Investigation on spinnability of low molecular weight alkaline lignin to fabricate biobased carbon fiber

Using acetic acid instead of dimethylformamide as solvent, lignin-based nanofibers were prepared by electrospinning with industrial low molecular weight lignin. After pre-oxidation and carbonization, the fibril was transformed into carbon fiber. The results showed that different viscosity of spinning solution and different parameters of electrospinning have great influence on the morphology of fibers. The diameter of fibers could be concentrated in 300-500nm by using the best electrospinning process. After carbonizing the fibers, it was found that the lignin fibers could retain the morphology of the fibers after carbonization at a suitable heating rate and holding temperature. This study showed the conditions required for the preparation of carbon fiber from low molecular weight lignin, and provided a way for high value utilization of waste biomass and green preparation of carbon fiber.

Flame Heat Sources as a Sustainable Method of Protecting Fruit Orchards against Frost in Poland

One of the key factors affecting the yield of fruit orchards is their protection against spring frosts. This paper presents the methods currently used (like anti-frost nets, chemical agents, etc.) and proposes an alternative method of raising the temperature around fruit trees using flame heat sources with a suitable heating power. Flame heat sources in the form of metal containers filled with paraffin were utilised in this experiment. The effect of the flame heat sources on the relative increase in the temperature of a wooden surface (simulating trees located in Rzeszow, Poland) depending on the distance from the heat source was measured and estimated based on mathematical models. Based on the results of experimental work, an optimal placement of flame heat sources (1.58 m from each tree) was proposed for orchards of semi-dwarf fruit trees. The proposed modifications of the flame heat sources to incorporate infrared radiation converters resulted in a greater increase in the temperature of the wooden surface. The analysis of the available economic and environmental data showed that the proposed method may be a competitive alternative to the standard method of protection. If the flame heat sources are filled with combustible materials derived from renewable sources, such as those produced from fats, the overall CO2 emission balance for this solution will be significantly more favourable. The use of flame heat sources does not necessitate the introduction of permanent changes in the environment, as is required in cases when irrigation infrastructure is installed.

Developing a framework to evaluate the life cycle energy and greenhouse gas emissions of space heating systems using zeolite 13× as an adsorbent material

The wide use of fossil-based space heating systems results in significant greenhouse gas (GHG) emissions. Using solar energy for space heating can help reduce GHG emissions. However, solar energy generation is intermittent and the energy needs to be stored for continuous supply. The zeolite 13× adsorbent heat storage system for space heating is a promising alternative. There is very limited research on the life cycle GHG footprint of this type of adsorbent storage system. In this study, we developed a framework that integrates engineering design with life cycle assessment to evaluate the energy and emission performances of a zeolite 13×-based heating system charged by a solar air collector. A simulation model was developed for this adsorbent storage system. The life cycle GHG emissions of the residential heating system are estimated to be 0.1160 kg CO2 eq per kWh of the heat delivered over a 20-year lifetime. The operational phase contributes 74 % of the overall emissions because of the energy required by the humidifiers. The material production stage accounts for 25 %, mainly attributed to the upstream emissions in the manufacturing of photovoltaic thermal (PVT) air solar systems. The net energy ratio (NER), which is the ratio of energy output to fossil energy input, is 2.9. The continuous days without sunlight, the adsorbent vessel length-to-diameter ratio (L/D), and the pellet diameter of the zeolite 13× storage appear to be the parameters most sensitive to both emissions and NER. The uncertainty analysis shows emissions and NERs of the space heating system in the range of 97.2–152.3 g CO2 eq/kWh and 2.4–3.0, respectively. Compared with other alternative heating systems in the market, the adsorbent system has a much better GHG performance. The research highlights the importance of selecting a suitable space heating system given the high influence of operational energy on the life cycle emissions and the range of electricity generation emissions in different provinces.

Substitution of heating systems in the Italian buildings panorama and potential for energy, environmental and economic efficiency improvement

In many countries, old inefficient generators are used for heating purposes. A way to improve energy efficiency in those countries can be the choice of the most suitable heating generators to replace the current ones, without the inconveniences caused by other retrofit measures. In this context, we present a methodology to choose the most appropriate generator through dynamic simulations applied to building stock energy models. Economic, energetic, and environmental parameters guide the choice. The methodology is applied in the Italian residential building scenario, where the most widespread heating device is traditional boiler. Three options are considered: condensing boiler, heat pump, and hybrid heat pump (an alternative-working system with a condensing boiler and heat pump). For a detailed analysis, a white-box bottom-up building stock energy model is defined, through a statistical analysis, consisting of four building typologies in three different external climates. An hourly dynamic building-system simulation has been performed to obtain energy performance, emissions, and operational costs. The results have demonstrated that condensing boiler allows limited economic, environmental, and energy savings (8-14%), compared to traditional boiler. The highest economic savings are obtained with the hybrid heat pump (20%), while the heat pump alone leads to higher costs, but the highest savings in emissions and non-renewable primary energy (25-50%). The flexibility offered by the hybrid heat pump allows to obtain high savings in different cost scenarios, but also to further reduce CO2 emissions by implementing an environmental-based control strategy.

Performance Modelling of Co-Fired Palm Kernel Shell -Pulverized Coal Blend in Steam Power Plant

This study investigates the performance of co-firing palm kernel shell (PKS) and pulverized coal in a steam power cycle. The process simulation software Aspen Hysys was used in the simulation. The study analyzed the various emitted combustion product gases. The cycle efficiency and Power output for each fuel sample blend was carried out. This provided the basis for the performance comparison of each fuel sample. The Sample D with mix ratio 80 (coal)-20 (PKS) came out the best fuel blend having a CO2 emission of 1844.198854 Kgmol/h, an SO2 emission of 8.830612928 kgmol/h, a cycle efficiency of 0.41 and an estimated power of 104, 076 kW. It was concluded that coal blended with palm kernel shell at a mix ratio of 80-20 has a suitable heating value for steam generation which promotes a cleaner coal usage with a significant reduction in the emission levels of greenhouse gases.

Physicochemical properties and in vitro digestion behavior of emulsion gels stabilized by rice bran protein aggregates: Effects of heating time and induction methods

To investigate the effects of heating time and induction methods on the physicochemical properties and in vitro digestion behavior of emulsion gels, rice bran protein aggregates (RBPAs) were formed by acid-heat induction (90 °C, pH 2.0) and the emulsion gels were further prepared by adding GDL or/and laccase for single/double cross-linked induction. Heating time affected the aggregation and oil/water interfacial adsorption behavior of RBPAs. Suitable heating (1–6 h) was conducive to faster and more adsorption of aggregates at the oil/water interface. While excessive heating (7–10 h) resulted in protein precipitation, which inhibited the adsorption at the oil/water interface. The heating time at 2, 4, 5 and 6 h was thus chosen to prepare the subsequent emulsion gels. Compared with the single cross-linked emulsion gels, the double-cross-linked emulsion gels showed higher water holding capacity (WHC). After simulated gastrointestinal digestion, the single/double cross-linked emulsion gels all exhibited slow-release effect on free fatty acid (FFA). Moreover, the WHC and final FFA release rate of emulsion gels were closely related to the surface hydrophobicity, molecular flexibility, sulfhydryl, disulfide bond and interface behavior of RBPAs. Generally, these findings proved the potential of emulsion gels in designing fat alternatives, which could provide a novel technique for the fabrication of low-fat food.

Growth Mechanism and Corrosion Resistance of a Co-Al Layered Double Hydroxide Film Grown In Situ on a Steel Substrate

The growth mechanism of layered double hydroxide (LDH) films grown in situ on steel via hydrothermal treatment is still unclear. In this study, the mechanism of Co-Al-CO3-LDH film grown in situ on a steel substrate was investigated in detail. During the hydrothermal reaction, the in situ growth process of Co-Al LDH on steel involved three steps: (1) hydrolysis of Al3+ and etching of the steel surface, (2) hydrolysis of urea and promotion of LDH nuclei, and (3) crystallization of LDH. More importantly, the generation of Al(OH)3 determined the integrity of the LDH film grown on the steel surface, and a suitable heating rate was also the key factor that affected the growth of the ordered and regular LDH nanoflakes. Therefore, this work provides a comprehensive understanding of the in situ LDH growth mechanism on steel and may facilitate optimal LDH film preparation.

Effects of Heating Treatment on Functional and Structural Properties of Liquid Whole Egg

Liquid whole egg (LWE) products have many advantages such as convenient transportation, easy production and are safe. However, LWE has a short shelf life and high thermal sensitivity, so suitable heating treatment is the key to the production of LWE products. The aim of this study is to investigate the effects of heating treatments conditions (at 55-67 °C for 0-10 min) on the emulsification, foaming activity and rheological properties of LWE. The results indicated that the emulsifying activity of LWE had no significant change after 55-64 °C heating treatment, while it decreased significantly after heating treatment at 67 °C. The foaming property of LWE increased significantly after 55 °C to the 64 °C heating treatment; while the foaming property showed a downward trend with the increase in heat treatment temperature, it can significantly improve the foam stability of LWE. The heating treatment thoroughly changed the molecular weight distribution of LWE protein, thus promoted the protein surface hydrophobicity, hydrophobicity activity and rheological properties. The heating treatment at 61 °C for 6 min had a better effect on the functional properties than that of the other heating groups. In addition, the results of this study provide the change in rules of LWE under different heating treatment conditions and provide theoretical guidance for the production and processing of LWE.

Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

In the present article, experimental results regarding fully integrated superconducting quantum interference devices (SQUID), including a circuit to tune and optimize the main sensor device characteristics, are reported. We show the possibility of modifying the critical current of a SQUID magnetometer in liquid helium by means of a suitable heating circuit. This allows us to improve the characteristics of the SQUID sensor and in particular to optimize the voltage-magnetic flux characteristic and the relative transfer factor (responsivity) and consequently to also improve the flux and magnetic field noise. It is also possible to reset the SQUID sensor in case of entrapment of magnetic flux, avoiding taking it out of the helium bath. These results are very useful in view of most SQUID applications such as those requiring large multichannel systems in which it is desirable to optimize and eventually reset the magnetic sensors in a simple and effective way.

Low-dimensional composites-based planar heater with high-exothermic characteristics in cold water environments

This work presents a high-performance planar heater that generates a high-temperature heat even in cold water environments. The planar heater was fabricated with low-dimensional composites prepared with MXene, carbon nanotube (CNT), and waterborne polyurethane (WPU) on polyimide (PI) film by blade coating. The planar heater installed in life-jacket was rapidly heated up to 73 °C in 1 min at 3.6 V in the atmosphere. For a cold water of 5 °C, the planar heater combined with the insulating film was effectively heated and maintained in 45–50 °C at 3.6 V due to the insulation effect for cold water. Thus, the insulated planar heater generates a heat of high temperature and can effectively transfer more heat to the body even in the cold water. Our developed planar heater will be expected to be utilized as a suitable wearable heating device for cold environments.

An experimental investigation into the combustion properties, performance, emissions, and cost reduction of using heavy and light fuel oils

Heavy fuel oil (HFO) is a fuel that can be used in compression ignition engines because of its cheapness and low operating costs. However, heavy fuel oil is not compatible with most diesel engines and combustion systems in use. As a result, there is a decrease in the efficiency of the combustion process. To treat this problem, and for the purpose of using heavy fuel oil, the characteristics of the diesel engine fuel and combustion system were improved in this study. The high viscosity of heavy fuel oil was reduced (before it was introduced into the engine) by adding a suitable heating device in the fuel line. Light fuel oil (LFO) is also blended with heavy fuel oil to reduce the viscosity of the fuel. HFO properties, such as viscosity, density, calorific value, and sulfur content, were determined. A blend called LFO-H20 (80% LFO:20% HFO) was prepared and tested in a single-cylinder diesel engine. This engine performance and exhaust emissions were evaluated using LFO, HFO (70°C), LFO-H20 and LFO-H20 (70°C). The tests were conducted using a one-cylinder test rig, Kirloskar, which is naturally aspirated, direct injection and has maximum speed of 1500 rpm diesel engine. The results showed that the Brake Thermal Efficiency (BTE) for HFO (70°C), LFO-H20 and LFO-H20 (70°C) was (31.21%, 22.5%, and 10.4%) lower than LFO. The Brake Specific Fuel Consumption (BSFC) also increased by about (28.93%, 20.1%, and 10.5%) compared to LFO. The oxides of nitrogen (NOx) were increased at HFO and single blend fuel by about (19.64%, 11.92%, and 7.53%) compared to LFO. In addition, the unburned hydrocarbon (UHC) for HFO (70°C), LFO-H20 and LFO-H20 (70°C) was (42%, 28.7%, and 18.4%) higher than LFO. The CO concentrations increased by (38.4%, 30.6%, and 18%) compared to LFO. Finally, the smoke opacity values of HFO (70°C), LFO-H20 and LFO-H20 (70°C) were increased by (42%, 26% and 17.2%) respectively. The effect of heating tested fuels at a temperature of (70 °C) resulted in decreasing their density and viscosity, which improved the fuel combustion spray characteristics and enhanced the engine performance and emission.

Hot-air-assisted radio frequency blanching of broccoli: heating uniformity, physicochemical parameters, bioactive compounds, and microstructure.

Vegetables are often blanched before drying. The hot-water blanching (HWB) of broccoli reduces quality and is environmentally harmful. In this work, hot-air-assisted radio frequency heating blanching (HA-RFB) of broccoli was developed for use before further drying processes. Blanching sufficiency, heating uniformity, and heating rate during HA-RFB were investigated to improve the product's physicochemical properties and texture. Suitable heating conditions were achieved when HA-RFB was applied with hot air at 70 °C, with an electrode gap of 10.7 cm, using a cylindrical container for the broccoli. Under these conditions, the relative peroxidase activity in broccoli decreased to 3.26% within 117 s, with 13.45% of weight loss. In comparison with HWB broccoli, the products blanched by HA-RFB preserved their texture, bioactive compounds, and microstructure better. The ascorbic acid, sulforaphane, and total glucosinolate content in HA-RFB products were 251.1%, 131.9% and 36.7% higher than those in HWB broccoli, and HA-RFB treatment led to a greater weight loss (13.45 ± 0.50%) than HWB (8.70 ± 1.70%), which is very helpful for the subsequent drying process. This study demonstrated that HA-RFB could be a promising substitute for HWB to blanch broccoli and other flower vegetables, especially as a pretreatment in the drying process. © 2023 Society of Chemical Industry.

Effects of heating process on 3D printing properties of Pennahia argentata surimi: Water distribution, gel formation, rheology, chemical bonds

AbstractThe gel is an important factor in 3D printability of Pennahia argentata surimi. While surimi gel is sensitive to temperature and influenced by chemical bonds changes. Hence, preheating effects on printing and material properties of surimi were investigated. Results shown hydrogen bonds and ionic bonds contents in surimi under different heating conditions decreased about 20%–90%. Meanwhile, hydrophobic force and disulfide bonds increased about 0.2–6 times. These changes formed more gel, as well as 6.5% at most immovable water transferred into free water which enhanced texture properties and made solid properties of rheology in surimi dominant. This phenomenon occurred significantly in temperature range of gel formation (35–40°C, 90°C) while became extinct at 45°C with 10–30 min due to gel degradation. These made surimi by heating exhibit strong mechanical strength, which is conducive to forming process when printing after extrusion. However, if they occurred before extrusion, these could increase extrusion difficulty to make filamentous materials be broken easily after extrusion, weakening printing effect. Hence, preheating of surimi before extrusion was not suitable for 3D printing. While short‐time heating during or after extrusion might be more appropriate for printed surimi, promoting the application of surimi in 3D printing technology.Practical Applications3D printing is a new technology in food processing that refers the process of connecting or curing materials to form 3D objects by continuously adding layers of materials. Surimi is one of the suitable materials which can promote the process of printing. While the material properties of surimi are affected by temperature that influences the printing effects. The purpose of this study was to investigate the effects of different temperatures on the material properties of Pennahia argentata surimi, and determine the suitable heating process of printed surimi products. These results could promote the application of 3D printing technology in surimi processing.

Wax Printing Technology as a Printing Model for Craft Goods Based on Additive Manufacturing

The application of Additive Manufacturing has brought progress and transformation in the industrial world. 3D printing technology is advantageous over traditional manufacturing processes, as it can turn 3D designs/models into ready-to-use products. This research aims to identify the wax printing process as a printing model for the craft industry using additive manufacturing-based technology. Studies related to wax printing technology using a 3D printer to print handicrafts are needed to find out the characteristics of wax as the primary printing material, what parameters of the printing process are required for the wax printing process, and what kind of 3D printing technology is appropriate in the wax printing process, especially for use in the craft industry. Testing wax model printing using an FDM 3D Printer with the most suitable heating temperature of 2000C and a retract distance of 50 mm using wax material in the filament. Shrinkage resulting from the wax printing process has a minimal value, with an average minimum shrinkage of 1.16% and a maximum average enlargement of 0.02%, which indicates that this technology is suitable for use in the printing process of handicraft models.

Synthesis of KOH-activated carbon aerogel for the efficient removal of crystal violet from aqueous solutions

In this study, a low-cost jackfruit based KOH-activated carbon aerogel (AJCA) is prepared from facile hydrothermal treatment synthesized core of jackfruit with different heating rate. AJCA is sythesisized to absorb crystal violet (CV) dye from aqueous solutions and effectively treat other dyes. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) allow for targeted analysis of sample surfaces which has many grooves of varying depth, and many layers of scales stack on top of each other. The specific surface area, which is examined by The Brunauer-Emmett-Teller (BET) method, reaches 592.65 m2/g. The most suitable heating rate is 3 degrees per minute (AJCA-3). The maximum adsorption capacity is 386,66 mg/g and the absorption performance reaches 96,5% at a concentration of 300 ppm, which indicates that AJCA-3 is very efficient and competitive with several adsorbents. The pseudo-second-order model satisfactorily describes the adsorption kinetics, and the Langmuir model was suitable to represent the adsorption equilibrium. These experiments show that AJCA has excellent potential on treating real coloured eflluents.

Feasibility of a snow-melting membrane roof with an electrical–thermal system and prediction of its performance

Snow removal from membrane structures used for roofing is a critical activity to effectively avoid collapse accidents caused by non-uniform snow distribution. Electrical–thermal systems that combine electrical with thermal techniques are proposed as a substitute for chemical and mechanical snow removal methods. These systems overcome the problems of conventional chemical-based snow- melting in construction material corrosion and environmental pollution. The aims of this study are to analyze the performance of an automatic snow-melting membrane roof utilizing an electrical–thermal system with heating wires, determine the suitable heating wire parameters and climatic conditions based on the snow-melting performance, and evaluate the system using experimental data. The findings indicate that a copper–nickel alloy heating wire can provide a stable heat source and is suitable for electrical–thermal systems. The surface temperature reached a stable point at 38 °C after 240 min of heating using electrical energy. The recommended heating wire parameters were identified based on the snow-melting performance and energy consumption. The optimal heating wire spacing is 7.5 cm and the most energy-efficient heating wire power is 250 W/m2. The automatic snow-melting membrane roof is always free of snow if snow melting is started at the instant when the snow thickness is less than 20 mm and the solar irradiance is in the range of 100–250 W/m2. The ambient temperature contributes minimally to the snow-melting performance. Finally, artificial neural network (ANN) and multiple linear regression (MLR) models were built to predict the snow-melting performance using the aforementioned parameters as inputs. The ANN model can predict and evaluate the snow-melting performance trend more accurately than the MLR model. The results indicate the possibility for large-scale practical engineering applications of electrical–thermal systems for snow removal.