Optimum Heating Time Research Articles

Microwave self-healing characteristics of the internal voids in steel slag asphalt mixture subjected to salt-freeze-thaw cycles

Microwave heating technology can be used to repair freeze-thaw (F-T) cycle damage and cracks caused by the use of snow melting salts and de-icers in winter. This study utilized three different gradations of asphalt mixtures: AC-13, SMA-13, and OGFC-13, and enhanced their microwave absorption performance with steel slag (SS). The heating uniformity was evaluated through surface and internal temperature tests. Additionally, the mechanisms of damage and healing of the asphalt mixtures under salt freeze-thaw (S-F-T) damage conditions were explored using S-F-T cycles test and X-ray computed tomography scans (CT). The results showed that OGFC-13 exhibits a significantly higher rate of temperature increase compared to the other two types due to its stronger wave absorption capacity. The thermal hysteresis caused by steel slag leads to uneven spatial temperature distribution. The study recommends an optimal microwave heating time of 40 s for SS asphalt mixtures, which has minimal impact on the mixture structure, by defining an evaluation method for the uniformity index and local overheat ratio. After undergoing S-F-T cycles, the porosity of all three asphalt mixtures increased, particularly at the top and bottom of the specimens. Among them, OGFC-13 exhibited the poorest durability under S-F-T conditions, with the S-F-T cycles having a significant impact on medium-sized voids (0.15–0.6 mm). After microwave heating, AC-13 and SMA-13 showed good repair effects, with porosity levels returning to their initial states. For large voids (>2.36 mm) in OGFC, microwave heating may not effectively reduce the number of voids. Additionally, the healing rate of mixture specimens at certain mid-height ranges is higher due to elevated surface temperatures in these areas, making it especially effective in repairing F-T damage. This study shows that microwave heating of SS asphalt mixtures can improve the durability of pavement in cold regions. However, implementation challenges include the need for specialized equipment and potential uneven heating. Future research should explore optimizing microwave heating techniques to minimize local overheating and investigate the long-term performance of microwave-repaired asphalt pavements under various environmental conditions.

Enhancement of Microwave Heating Technology for Emulsified Asphalt Mixtures Using SiC-Fe3O4 Composite Material.

The application of microwave heating technology can significantly enhance the water evaporation rate of emulsified asphalt mixtures post paving. To improve the microwave absorption and curing performance of these mixtures, SiC-Fe3O4 composite material (SF) was incorporated. This addition aims to enhance the microwave absorption efficiency and accelerate the curing process of emulsified asphalt mixtures under microwave heating. This study begins with an analysis of the microwave absorption principles pertinent to emulsified asphalt mixtures. Subsequently, the microwave heating temperature fields of ordinary emulsified asphalt mixture (EAM), SiC emulsified asphalt mixture (S-EAM), Fe3O4 emulsified asphalt mixture (F-EAM), and SiC-Fe3O4 emulsified asphalt mixture (SF-EAM) were simulated using COMSOL Multiphysics finite element software (COMSOL 6.2). The early strength variations in SF-EAM under different microwave heating durations were then examined through adhesion tests, leading to the proposal of a microwave heat curing process for SF-EAM. Finally, the wear resistance, water damage resistance, rutting resistance, and skid resistance of SF-EAM post-microwave curing were evaluated through wet wheel wear tests, wheel track deformation tests, and road friction coefficient tests. The results indicate that the optimal microwave heating time is 90 s, with the microwave absorption performance of the materials ranked as follows: EAM, S-EAM, F-EAM, and SF-EAM, from lowest to highest. The road performance of SF-EAM complies with specification requirements, and its wear resistance, water damage resistance, and rutting resistance are notably improved after microwave heating.

Examining Shape Dependence on Small Mild Steel Specimens during Heating Processes.

With regard to the heating technology of small test specimens (D < 1 inch, i.e., 25.4 mm), only a limited amount of data and literature are available for making adequate technological decisions. Heating time of small geometric shapes is influenced by the technological parameters of the furnace, the temperature, the disposition technique in the furnace and the geometric characteristics of the workpiece. How to shorten heating time to achieve a suitable material structure is a vital question, while considerable energy is saved at the same time. Among the geometric characteristics, shape dependence is one of the important aspects that must be taken into account in terms of heating technology. Shape dependence is usually taken into account with empirically produced correction factors, which can result in significant oversizing of heating time, energy-wasting technology and material structure of insufficient fineness. In the course of our work, we investigated and compared the shape dependence of cylindrical and prismatic specimens with the same surface-to-volume ratios, which were combined with surface heat transfer analyses and geometric effect tests to formulate new approximate equations for determining heating time. As a result, we could mathematically derive a relationship between heating time, size and shape of the active surfaces, the correlation of which can shorten heating time by 20%. In addition, a shape factor (1.125) between cylinder and prismatic-shaped specimens was determined, which can be used with the new equation to calculate heating time for similar specimens. At last, a relationship is developed between the amount of heat that can be stored in the body during heat equalization and the complexity of the shape, which can be characterized through ratios depending on heating times and active surfaces in the function of total surface/volume ratio. Based on this relationship it can be determined more precisely when heat equalization occurs; therefore, shorter heating time can be achieved. In conclusion, with the help of this new method, optimal heating time for structural steel components, in the case of small cross-section and weight, can be determined.

Optimum heating time for warm forming of AA7075 aluminum alloy in T6 condition

Optimum heating time for warm forming of AA7075 aluminum alloy in T6 condition

Evaluation of Heating Time on Vacuum Preloading Treatment

A comparative study of the effect of a vacuum preloading combined intermittent heating method and conventional vacuum preloading treatment was designed and carried out through indoor model tests to investigate the optimal intermittent heating time. It is concluded that the mechanism of vacuum preloading combined with the intermittent heating method is to improve the permeability of soil to alleviate the clogging effect, and therefore has a treatment effect far beyond the conventional vacuum preloading method. The results also show that setting a heating time of 120 min and a stopping time of 60 min can obtain the best consolidation effect.

Photocatalytic Degradation of Lignin using TiO2 from Ilmenite Prepared by Microwave Method

This study investigates the photocatalytic degradation of lignin using TiO2 extracted from ilmenite through a microwave-assisted method. Characterization of the iron sand, which serves as the source of ilmenite, was conducted using X-ray fluorescence spectroscopy (XRF) and Energy Dispersive X-ray Spectroscopy (EDX). The XRF analysis revealed that the iron sand primarily consists of Fe and TiO2, with minor impurities such as Al2O3, MgO, and SiO2. After extraction, the iron mineral content increased significantly, while impurities decreased. EDX analysis confirmed the presence of Fe, O, and Ti elements in the iron sand sample, originating from various iron oxide phases. Subsequent degradation tests on lignin with varying microwave heating durations of ilmenite showed that a 90-minute heating duration achieved the highest lignin degradation percentage of 56.69%. This suggests that the optimum heating time for ilmenite is crucial for maximizing its photocatalytic activity. Overall, the findings highlight the potential of microwave-prepared TiO2 from ilmenite for efficient lignin degradation, with implications for environmental remediation and industrial applications.

Internet of things based smart system in the modified greenhouse solar dryer for agricultural products

The objective of this study is to develop a smart monitoring and control system for a modified greenhouse dryer for agricultural products utilizing Internet of Things (IoT) technologies and wireless sensor networks. This system enables real-time monitoring of air temperature and humidity, activation of the exhaust fan, adjustment of the heater, and determination of the optimal heating time. The investigation focused on the implementation of a microcontroller in the modified greenhouse system. The system possesses the capability to issue commands for the initiation of the heater and exhaust fan while also facilitating real-time monitoring. The system is equipped with an emergency command that can temporarily halt activities. The system utilizes two different temperature ranges, namely 45°C–50°C and 35°C–65°C, to analyse variations in heater usage across different temperature levels. Both software tools (Telegram and Google Excel spreadsheet) possess the functionality to monitor and regulate the temperature within a greenhouse by utilizing the chat network Telegram. Furthermore, the users possess the capability to store and access data related to the greenhouse system within an Excel spreadsheet.

Optimizing physico-chemical properties of hierarchical ZnO/TiO2 nano-film by the novel heating method for photocatalytic degradation of antibiotics and dye

The design of semiconductor catalysts with excellent photocatalytic properties, stability, recyclability, and good separation for the treatment of polluted water is still challenging. In this paper, the ZnO/TiO2 nano-thin films were fabricated using the magnetron sputtering technique and then heating the underlying ZnO layer and the upper TiO2 layer for their respective optimal heating time, i. e. heating ZnO for 3 h and heating TiO2 for 2 h. The as-prepared films were characterized. The results show that the preferred growth of TiO2 grains along the [001] axis, relatively large specific surface area, and increased amounts of surface oxygen vacancies (OVs) were induced to the heterojunction catalysts through this optimized heating strategy, which boosts the photocatalytic activity of ZnO/TiO2 nano-film. The degradation experiment inndicates that the ciprofloxacin (CIP) removal efficiency can reach 97.3% in 2 h duration, which was higher than that of the samples annealed for the same periods. Meanwhile, the prepared ZnO/TiO2 photocatalytic film exhibited favorable stability of 95.5% degradation efficiency after the fourth run and general applicability for the photodegradation of various contantains, whih removed 99.5% of ofloxacin (OFX) and 77.6% of tetracycline (TC) in 2 h and 94.1% of Rhodamine B (RhB) in 1 h. This work is expected to yields a novel insight into the production of heterojunction photocatalysts with excellen ability for photocatalytic degradation of pollutants in the practical industry.

Unleashing the potential of flash vacuum expansion: an innovative approach for Andean Blackberry (Rubus glaucus Benth) Processing

Andean Blackberry fruits (Rubus glaucus Benth) have promising market potential with notable nutritional and antioxidant properties; however, their limited 3-6day shelf-life presents considerable challenges. A flash vacuum expansion (FVE) process coupled with vacuum de-pulping was used to obtain puree from blackberry fruits. Different steam heating holding times (53, 75, 85, and 95 s) were tested at a pressure of 130 kPa. After FVE and vacuum de-pulping (5kPa), various parameters, including alcohol insoluble residues (AIR), residual activity of polyphenol oxidase (RAPPO), anthocyanins, ascorbic acid and ellagitannin retention, rheological properties, and microbial reduction, were evaluated in the purees. Optimal steam heating time of 85 seconds was selected for the FVE process, showing outstanding retention rates of 98% for cyanidin-3-O-glucoside and 88% for ascorbic acid, along with enhanced ellagitannins extraction from torus and seed blackberries into the puree. The purees displayed a gradual shear-thinning flow behavior, positively correlated with the increase in %AIR. A reduction greater than 5 Log10 CFU / mL was achieved for molds, yeasts, aerobic mesophilic, and coliforms counts for all the treatments. Nectar and sweetened puree products developed from the optimal FVE processed puree, received favorable acceptance from consumers, with a high intention to purchase. The findings demonstrated that this innovative process has great potential for developing of high-quality products.

Development of a novel induction-heated reactor to enhance the performance of waste tires pyrolysis

Waste tire pyrolysis (WTP) is well-known as a promising technique for waste tires (WTs) management. However, the requirements of high cost and intense energy, as well as steel wire stripping remain the major drawbacks for the widespread applications of WTP technologies. In this research, a novel induction-heated pyrolysis (IHP) reactor has been developed to enhance the performance of WTP and the results were compared with a conventional fixed bed pyrolysis (FBP) reactor. The performance of the IHP reactor has been evaluated using three different feedstocks of sidewall (no steel wire), tread section (20% steel wire), and real mode (14% steel wire) at two different sizes of A and B. The results revealed that the presence of steel wire in the IHP reactor not only reduced the effect of WTs particles size, but also improved the average heat and oil production rate up to 36 % and 60 %, respectively through better heat distribution. The minimum REC (13.03 KJ/g) was achieved for the tread section after 12 min of the IHP process. The comparison of the results of the IHP reactor and the FBP reactor proved that using IHP reactor could significantly improve the performance WTP in terms of optimum heating time, heat rate, REC and power consuming cost up to 68 %, 44 %, 56 % and 61 % respectively. The findings of this study suggest IHP reactor which eliminates the need of stripping steel wires as novel and promising approach for sustainable WTs management.

Enhanced effect of self-propagating subsequent heating on the expansive pressure on soundless chemical demolition agent

Soundless cracking demolition technology is an essential method for demolition of buildings in place of engineering blasting in complex environments. However, the temperature dependence of soundless chemical demolition agent (SCDA) dramatically restricts the development and application of this technology. For this reason, the enhanced effect of subsequent heating on the expansive pressure of SCDA is examined in this study. A self-propagating heating tube was designed. After determining the optimal heating time through uniaxial compressive strength (UCS), the SCDA expansive pressure measurement experiment was carried out under different heating conditions. Therefore, the enhanced effect of heating on SCDA expansive pressure was examined, and the enhanced mechanism was revealed by analyzing the microstructure and hydration products. The research results show that the UCS of SCDA has a linear relationship with the ambient temperature, and the optimal heating time can be determined by the UCS formula. After heating, the temperature and expansive pressure of SCDA increase suddenly. To reflect the influence of heating on the development of expansive pressure, a functional relationship of expansion pressure–time-ambient temperature is proposed. Heating can significantly accelerate the hydration process of SCDA and make dense Ca(OH)2 grains formed inside it. This is the intrinsic reason for the mutant growth in the expansive pressure of SCDA. This work broadens the application scenarios of SCDA and provides new ideas for the growth of expansive pressure.

Optimization of the Carbonization Parameter of Exhausted Coffee Husk (ECH) as Biochar for Pb and Cu Removal Based on Energy Consumption

Recent studies on agricultural waste as a potential precursor of biochar for heavy metals removal from aqueous solution had not considered exhausted coffee husk (ECH) as the potential one. It is well-known that the carbonization process influences the removal performance of biochar, particularly removal efficiency (RE). However, previous studies rarely considered the energy consumption during the carbonization process. The major objective of this study is to investigate the optimum carbonization parameter on ECH biochar for removal of ion Pb and Cu from economic stand point. The ECH biochar was produced at the different heating temperature (300 – 600°C) and heating time (30 – 120 minutes). In regard to specific cost of bio-sorption, the results showed that 500°C was the optimum heating temperature of ECH biochar for the Pb removal, while 600°C was the optimum one for the Cu removal. Furthermore, the heating time experimental outcomes suggested that the optimum heating time were 30 minutes for Pb removal and 120 minutes done Cu removal. Key words: Biochar, carbonization temperature, carbonization time, exhausted coffee husk, specific energy cost

Ultrafast soliton delivered by miniaturized mode-locker with MoTe2 and core-expanded fiber.

Thermally expanded core (TEC) technology is an effective method of high-power fiber lasers. Miniaturization is also a major challenge for high-power lasers. We have proposed a miniaturized mode-locker based on TEC fiber and MoTe2-polyvinyl alcohol (PVA) film. The proposed mode-locker is consisting of two TEC ferrules, a piece of MoTe2-PVA film and a ceramic sleeve. The length of the proposed device is about 20 mm, and its outer diameter is about 2 mm. The relations between heating time, heating temperature, and mode field diameter (MFD) have been numerically simulated. The bending loss with respect to MFD has also been analyzed. The simulation results have revealed the trade-off relation between maximal tolerable intensity and low cavity loss, which means that there is an optimal MFD corresponding to optimal heating time and heating temperature. The proposed mode-locker has been applied in an integrated fiber laser, which has emitted ultrafast soliton with 3 times intensity larger than that of conventional sandwiched-type saturable absorber. The proposed mode-locker and fiber laser will find important applications in laser processing, laser ranging, and optical communication.

Improvement of engineering solutions on friction-anchored rockbolting in mine support in difficult geological conditions

Increasingly deeper level mining in highly complicated geological conditions dictates improvement of the existing systems of mine support. The pilot commercial testing which have been implemented for 13 years in mines in Russia, Kazakhstan, Uzbekistan and Kyrgyzstan makes it possible to develop and improve friction-anchored rockbolting technologies of different geological and geotechnical conditions. The promising mine support technologies should be based on integration of mixed-type support designs including friction-anchored rock bolts, reinforcement and, sometimes, pre-treatment of adjacent rock mass. Under conditions of rockburst hazard, it is recommended to combine various rockbolting systems. The system of friction-anchored rock bolts and reinforcement ensures sufficient load-bearing capacity in case of adjacent rock mass displacement owing to the use of a special friction-anchored bolt insert of a smaller diameter. In this case, given low yielding of the rock bolt material, it is possible to provide its sufficient extension. After a series of tests, it is found that the limiting load preceding displacement of the face plate is 128.8 to 141.2 kN. The &lsquo;yield&rsquo; of the face plate, from the load of 50 kN up to the limiting load, is 8.1&ndash;9.2 mm. When the limiting load is reached, the external diameter of the thrust decreases and the thrust &lsquo;passes through&rsquo; the hole in the plate, which favors stability of a roadway in case of dynamic events. Neither the thrust no the rod experiences damage in this case. The essential scatter in the values of the limiting loads is conditioned by the difference (instability) in heating time of the rod before the formation of the thrust. The optimal heating time is 2.5 s, and it is maintained and held in case of complete automation of friction-anchored rock bolt manufacture. The promising design solutions on mine support systems using friction-anchored rock bolts are identified.

Application of High-Frequency Defrosting, Superheated Steam, and Quick-Freezing Treatments to Improve the Quality of Seafood Home Meal Replacement Products Consisting of the Adductor Muscle of Pen Shells and Common Squid Meat

We developed a new seafood home meal replacement (HMR) product containing the adductor muscle of the pen shell (AMPS) and common squid meat (CSM) via high-frequency defrosting (HFD), superheated steam, and quick freezing. Test HMR products were produced by mixing defrosted and roasted AMPS, CSM, and sauce in ratios of 27.5, 27.5, and 45.0% (w/w), respectively, followed by quick freezing at −35 °C in a polypropylene plastic bowl covered with a plastic film. The chemical characteristics, nutritional quality, microbial and sensory properties, and shelf life of the product were examined. The response surface methodology identified the optimal temperature and heating time of the superheated steam for AMPS (220 °C, 1 min) and CSM (300 °C, 1.5 min). Chemical characteristics showed low levels of volatile basic nitrogen (9.45 mg%) and thiobarbituric acid-reactive substances (1.13 mg Malondialdehyde [MDA]/kg). No significant changes (p &lt; 0.05) were observed in microbial, color, flavor, taste, texture, and overall acceptance at −23 °C for 90 days. After reheating, the sensory scores varied from “like moderately” to “like very much.” The shelf life of the HMR product was estimated to be 24 months. In conclusion, HFD, superheated steam, and quick freezing successfully improved product quality, with little loss of nutrition and texture.

The Prospect of Microwave Heating: Towards a Faster and Deeper Crack Healing in Asphalt Pavement

Microwave heating has been shown to be an effective method of heating asphalt concrete and in turn healing the damage. As such, microwave heating holds great potential in rapid (1–3 min) and effective damage healing, resulting in improvement in the service life, safety, and sustainability of asphalt pavement. This study focused on the microwave healing effect on porous asphalt concrete. Steel wool fibres were incorporated into porous asphalt to improve the microwave heating efficiency, and the optimum microwave heating time was determined. Afterwards, the microwave healing efficiency was evaluated using a semi–circular bending and healing programme. The results show that the microwave healing effect is largely determined by the steel fibre content and the mix design of the porous asphalt concrete.. Besides, the uneven heating effect of microwave contributes to an unstable damage recovery in the asphalt mixture, which makes it less efficient than induction heating. However, microwaves exhibited the ability to penetrate further into the depth of the test specimen and heat beneath the surface, indicating deeper damage recovery prospects.

Does the combination of hyperthermia with low LET (linear energy transfer) radiation induce anti-tumor effects equivalent to those seen with high LET radiation alone?

Introduction The combination of hyperthermia with low LET (linear energy transfer) radiation may have similar anti-tumor effects as high LET radiation alone. This pre-clinical study determined the optimal heating temperature and time interval between radiation and heat to achieve this equivalent effect. Methods C3H mammary carcinomas (200 mm3 in size) growing in the right rear foot of CDF1 mice was used in all experiments. Tumors were locally irradiated with graded doses of either 240 kV ortho- or 6 MV mega-voltage X-rays to produce full dose-response curves. Heating (41.0–43.5 °C; 60 min) was achieved by immersing the tumor bearing foot in a water-bath applied at the same time, or up to 4-hours after, irradiating. The endpoint was the percentage of mice showing local tumor control at 90 days, with enhancements calculated from the ratios of the radiation doses causing 50% tumor control (± 95% confidence intervals). Results Previous published results in this tumor model reported that carbon ions were 1.3–1.7 times more effective than low LET radiation at inducing tumor control. Similar enhancements occurred with a temperature of only 41.0 °C with a simultaneous heat and radiation treatment. However, higher temperatures were needed with the introduction of any interval; at 42.5 °C, the enhancement was 2.5 with a simultaneous treatment, decreasing to a value within the carbon ion range with a 4-hour interval. Conclusions Combining hyperthermia with low LET radiation can be as effective as high LET at inducing tumor control, but the temperature needed depended on the time interval between the two modalities.

Derivatization and Spectrophotometric Quantification of Pamidronate in Bulk and Dosage Forms

Aims: To quantify pamidronate in a sensitive and accurate way either in bulk or dosage forms.&#x0D; Methodology: The quantification of this group of drugs is a challenging task as they lack the presence of chromophore groups in their structure. The proposed method depends on the derivatization of the studied drug by its reaction with 4-Chloro-7-nitro-2,1,3-benzoxazole and the product is measured spectrophotometrically at 470 nm. The conditions for the reaction are optimized regarding the volume of the reagent, the optimum pH for the reaction completion, the buffer volume, the optimum temperature for the reaction and the optimum heating time.&#x0D; Results: The studied drug can be determined in the range of 9-30 µg/mL after optimizing the reaction conditions. Method validation is performed according to ICH guidelines and different validation parameters like, linearity, accuracy, precision and robustness are calculated and found to be excellent.&#x0D; Conclusion: The proposed method is accurate, sensitive and can be applied for the routine analysis of pamidronate in quality control laboratories.

Determining the optimum heating time of small sized test specimen made from weldable mild steel

The usage of CHT (Continuous Heating Transformations) diagrams for a given steel or equivalent grade, requires knowledge of heating temperature, average heating rate, and the heating time. Definition of these technological parameters are primarily based on the complex relationship system between the geometric, thermal parameters and the heating device. In our research, we mainly focused on those physical key parameters that can mostly influence the heating and transformation rate. These parameters provide realistic, usable data for analysing the process of thermal diffusion and FEA (Finite Element Analysis) tests. During analysis, an easy-to-use function relationship was determined for approaching the heating rate more precisely. This method allows handling the CHT charts easily, within a selected range, regarding weldable mild steels.

Pemanfaatan Gulma Siam (Chromolaena odarata L.) Sebagai Adsorben Logam Timbal

This study aims to utilize (Chromolaena odorata L) as a metal adsorbent. The methods used to make activated charcoal are dehydration, carbonization, and activation. The activated carbon is then characterized to obtain activated charcoal that can be applied, then optimized. The results of activated carbon characterization obtained have reached the activated carbon quality requirements based on the Indonesian Industry Standard (SII No. 0258-88). Based on the adsorption test, the optimum pH of Pb2+ (Pb (NO3) 2 (in distilled water) Chromolaena odorata L charcoal activated by NaOH 0.2 M under varying pH (2,3,4,5,6) is at pH 5 with 69.00% absorption. The optimum contact time required for Pb ion adsorption is 4 hours at variation (1-5 hours) with 70.19% absorption. The optimum concentration at variation (concentration 20; 40; 60; 80; 100 ppm) on Pb ion adsorption is 100 ppm with 76.15% absorption. The optimum heating time is a variation of 1.5; 2; 2.5; and 3 hours of Pb ion adsorption is one hour 30 minutes with an absorption of 65.95%. Based on the optimization results, the activated carbon from the Chromolaena odorata L can be used as an adsorption material against the contamination of lead heavy metals (Pb).