Optimum Heating Time Research Articles

Optimization of preparation conditions for biochar derived from water hyacinth by using response surface methodology (RSM) and its application in Pb2+ removal

Abstract In this study, response surface method (RSM) was adopted to optimize the preparation conditions of water hyacinth biochar. The interaction on Pb2+ adsorption performance between the three basic preparation conditions of heating time (X1), heating temperature (X2) and heating rate (X3) were designed by Box-Behnken Design (BBD). The results showed that the mathematical model can fit the experimental data well. The significance of a single factor affecting followed by X2 > X3 > X1, and the interactive items as follows: X1X2 > X2X3 > X3X1. Through the analysis of variance and the numerical expectation function method, the optimal heating time is 2.65 h, heating temperature is 433 ℃, and heating rate is 19.96 ℃/min. The water hyacinth biochar was prepared under optimized conditions (OWHBC) to adsorb 50 mg/L Pb2+ solution. The actual experiment value of adsorption capacity (q) for Pb2+ was 24.94 mg/g, the predicted value of the model was 24.95 mg/g, and the error was only 0.02%. The maximum theoretical adsorption capacity (Qm) obtained with the Langmuir model were 195.24 mg/g for WHBC (prepared at center values of preparation conditions from single-factor experiments: 3 h, 400 ℃, and 20 ℃/min) and 251.39 mg/g for OWHBC, respectively. Through the determination of pH and specific surface area of biochar before and after optimization, it is proved that the RSM is feasible to optimize the preparation conditions of biochar. The results showed that RSM could optimize the preparation conditions of water hyacinth biochar and improve the adsorption ability of OWHBC to Pb2+.

Accelerated Healing in Asphalt Concrete via Laboratory Microwave Heating

Abstract Self-healing of asphalt concrete (AC) is highly dependent on temperature, and its healing capacity increases with elevated temperatures. The main objective of this study is to investigate the effect of microwave heating on promotion of self-healing in AC. With this purpose, two types of AC specimens (neat AC without additives and conductive AC containing steel fiber and graphite) were prepared to for use in thermal conductivity, microwave heating speed tests, four-point bending fatigue, and healing tests. In addition, oscillatory frequency sweep tests were carried out to obtain the flow behavior of asphalt binder. Results indicated that AC containing electrically conductive additives had a higher thermal conductivity and microwave heating speed than neat AC. It was also found that the fatigue resistance and healing capacity of conductive AC after microwave heating were higher than that of neat AC. Moreover, there exists a critical temperature (corresponding to near-Newtonian behavior temperature of asphalt binder) above which healing of AC starts and an optimum heating time (temperature) to maximize the healing effect. Finally, it was found that an intermittent heating mode with a cooling process is more effective than the consecutive heating mode to enhance the healing capacity of AC. Based on these findings, it is concluded that self-healing efficiency of AC can be enhanced via microwave heating.

Characterization of thermal distribution in 50-Liter biochar kiln at different heating times

Biochar has been known to be an excellent soil amendment. However, the biochar yield and its quality are both affected by the process parameter, such as temperature and heating time, and the production method from kiln type used. Therefore, the objective of this work was to characterize the thermal distribution inside the 50-liter kiln at different heating times of the biochar production. The experiments on the kiln with a dimension of 500 mm × 380 mm (height × diameter) including the fuel core with diameter of 115 mm with 5 rows of 6.35 mm drill puncture diameters were conducted. The biochar was produced from 7 kg of agricultural waste corncob. The pyrolysis temperature increased with increasing heating time and it was controlled not exceeding 600 °C by adjusting the briquette fuel quantity. The results showed that the highest temperature was found at the fuel core and decreased in radial direction outwards to the kiln wall. The heating time showed effect on the thermal distribution as well as the biochar yield. The lower thermal gradient and the higher biochar yield were obtained at the higher heating time. The biochar yield would, however, decrease after optimal heating time due to the decomposition and degradation of biochar derived from corncob during the pyrolysis process. The production cost of biochar was also determined. These findings propose agriculturists the optimal heating time along with the production cost to facilitate the biochar production.

The photo-transferred thermoluminescence phenomenon in case of emergency dose assessment

A major disadvantage of dose reconstruction by means of thermoluminescence (TL) is the fact that during readout of any TL material exposed to ionizing radiation (i.e., during measuring the glow curve), the radiation-induced signal gets lost. Application of the photo-transferred thermoluminescence phenomenon (PTTL) may offer a solution to this problem. In PTTL, the residual signal that is not destroyed by conventional TL readout (because it comes from deeper electron traps) can be readout through simultaneous stimulation by UV light and heating, allowing to obtain information about the absorbed dose in a second run. The present paper describes the application of PTTL for emergency dose assessment. For this, MTS-N thermoluminescent detectors (LiF: Mg, Ti) were exposed using a high-energy Clinac 2300 medical linear accelerator to doses of 100 mGy, 300 mGy, 500 mGy, 700 mGy and 1000 mGy. Irradiation with UV radiation allowed the determination of the optimal heating time of 3 h, while the optimal temperature was identified to be 70 °C. The results obtained demonstrated the usefulness of the PTTL method for emergency dose assessment. The efficiency of the PTTL method was determined as 19%. Finally it was found that the detector background after UV exposure should not be underestimated during routine dose measurements.

ПІДСИСТЕМА УПРАВЛІННЯ БЛОКОМ ПОВІТРОНАГРІВАЧІВ АСУТП ВИПЛАВКИ ЧАВУНУ В ДОМЕННІЙ ПЕЧІ

This article describes the operation of the automatic control unit of a blast furnace air heater unit. The analysis of the solutions currently existing. The subsystem operation algorithm, its input and output data are described.The subsystem is divided into modules and consists of the main module, which implements an algorithm for choosing the operating mode of the air heaters, a module for calculating the duration of heating and cooling of the air heater and the submodules responsible for theimplementation of various operating modes of the air heater. Also, in a separate module, the valve transfer subsystem between the modes is taken out The module for predicting the heating and cooling of the air heater and the valve transfer module are implemented separately and their structure is not described in the framework of this article. The module, in which the algorithm for heating the air heater is laid down, implements the algorithm for the minimum consumption of high-calorie additives to achieve the optimal heating time for the air heater. For this, the calculation of the predicted heating time of the air heater at the current calorific value of the fuel is performed. If the heating time of the heater is less than the set, you can reduce the consumption of high-calorie additives. If the heater at the current caloric value of the fuel heats up late, the consumption of high-calorie additives increases. The issue of automation of domain coolers is widely covered in modern works, but the latter require either modernization of existing units or sufficiently large computing resources. This article proposes a fairly simple control system that can be implemented on existing units without significant modernization and does not require a large amount of computation for its work. At the same time, it provides a sufficient effect.

Optimal Heating Temperature and Time for Echelon 10 and Excelsior SL-10 Shaping Using a Heat Gun.

The optimal heating temperature and time for the Echelon10 and Excelsior SL-10 microcatheters using a heat gun was investigated. The durability of the microcatheters after heat gun shaping for the second and third times was also examined. HAKKO FV-310 was used as the heat gun in this study. This heat gun can be set to 115°C, 125°C, and others. We measured the temperature at 2.5 cm from the nozzle of the heat gun. The Echelon10 and SL-10 microcatheters were shaped under two temperature conditions (115°C and 125°C) and three heating times (30 sec, 60 sec, and 90 sec). The microcatheter shape before heating had twice the curvature of the targeted shape. The temperatures at 2.5 cm from the nozzle were 120.6°C and 127.8°C with the heat gun set at 115°C and 125°C, respectively. There was no macroscopic difference in the results of heat gun shaping of the Echelon10 among temperature settings (115°C and 125°C) or heating times (30 sec, 60 sec, and 90 sec). As degeneration of the heated tip of the SL-10 at 125°C occurred in four of five trials, heat gun shaping was performed using the 115°C setting. There was no macroscopic difference in the results of heat gun shaping of the SL-10 among heating times. Shaping for the second and third times was successful at 115°C and 30-sec heating time. The Echelon10 and SL-10 can be successfully shaped from twice the curvature of the targeted shape using a heat gun at 120°C for 30 sec. Shaping for the second and third times was successful using the same settings. Degeneration of the SL-10 was noted at temperatures above 130°C.

Digital image correlation-based investigation of self-healing properties of ferrite-filled open-graded friction course asphalt mixture

Asphalt-based composites can self-heal, and this ability can be enhanced with induction heating and microwave heating. However, few methods are available to quantitatively analyze and monitor crack propagation in a composite before and after healing to evaluate the efficiency of self-healing. Digital image correlation (DIC) techniques, which are used herein, are widely applied for this purpose because they can directly measure the displacement field and strain field of an object under load. We conducted a three-point bending fatigue test and a three-point bending fracture test to study the influences of microwave heating time and healing time on the self-healing of asphalt-based composites with 5% ferrite and without ferrite. The influence of ferrite on the strain development process of the specimens was discussed based on the indexes of crack initiation time, crack propagation rate, and horizontal strain. The addition of ferrite can significantly delay secondary cracking and decrease the crack propagation rate of an open-graded friction course (OGFC) asphalt mixture. Based on DIC observations, the optimal microwave heating time for the OGFC asphalt mixture with 5% ferrite is 80 s. Meanwhile, the longer the healing time, the stronger is the healing effect, but the influence of healing time is weaker than that of heating time. Moreover, based on the change in the horizontal strain during crack development, it can be concluded that the addition of ferrite significantly improves the healing effect, in addition to improving the mixture toughness.

Effects analysis on optimal microwave energy consumption in the heating process of composite regeneration for the diesel particulate filter

It is difficult for diesel vehicle battery to meet microwave energy consumption during regeneration of diesel particulate filter, which restricts the application of microwave regeneration technology. In order to minimize the microwave energy consumption during the composite regeneration heating phase of the diesel particulate filter, an optimal microwave energy consumption model is established in this study based on the Functional Analysis Principles. The solution of this optimal model is simulated by the Adaptive Variable Scale Chaos Immune Algorithm. The optimized results are got and verified by experiments under different experimental cases. The simulation results show that an optimal microwave power and regeneration heating time can be effectively obtained during the composite regeneration heating phase. The experimental results indicate that optimization microwave energy consumption under 4 experimental cases decrease by 5.65%, 5.70%, 10.64% and 14.64% compared with that unoptimized data of 93.8 kJ, 75.6 kJ, 65.8 kJ and 56.7 kJ, respectively. The ratio of efficiency to energy of the optimized cases is higher than that of the cases without optimization. The effects of optimal microwave energy consumption in the heating process of composite regeneration are investigated. Moreover, the microwave assisted composite regeneration can save about 24% and 48% energy by contrast of the microwave regeneration and fuel post-injection regeneration. The proposed microwave energy consumption optimization method can save microwave energy and meet the regeneration performance requirement of the diesel particulate filter.

Thermal Pyrolysis of Municipal Solid Waste (MSW)

Plastics are very desired components, used in a lot of fields, from domestic packaging, agrarian, automotive, to building structure. The frequent use of plastic products related to their lightweight, high chemical stability and low cost.The present work aims to illustrating the thermal pyrplysis of two types of plastic: Polyethylene terephthalate (PET) and polystyrene (PS) in a batch tubular reactor. The reaction indicated that PS and PET were converted more meaningfully into useful liquid products out of thermally route compared to PET pyrolysis.The resulted liquid could be used as fuels or raw materials in chemical industries. Formation of oxygenates and aromatics were noticed.The maximum liquid produced at optimum temperature and optimum heating time (90 min) is 77%, 67.56%, 54% and 37.48% for PS, 10%PET + PS, 20%PET + PS and 30%PET + PS respectively. The liquid product is analysed by GC-MS at optimum condition. The compositions of the liquid produced are styrene monomer, toluene, alpha-methylstyrene, 1,3 Diphenylpropane, 1-Phenylnaphthalene, 4-phenyl-1 butene. The main product in the pyrolysis of PS is styrene monomer, 10%PET+PS, 20%PET+PS and 30%PET+PS.

Self-healing properties of ferrite-filled open-graded friction course (OGFC) asphalt mixture after moisture damage

Porous asphalt pavements have been widely used because of their advantages of drainage and noise reduction. However, these pavements are susceptible to moisture damage due to the characteristically large portion of air voids. Therefore, the maintenance of porous asphalt pavement has become one of the research hotspots. Microwave technology is generally used as a kind of high-efficiency maintenance method, but now it is also recommended as the technology to heal the micro-cracks in the pavement. However, there is little research conducted on its healing efficiency of asphalt mixture suffered from moisture damage. In this paper, the influence of ferrite content on the pavement performance, mechanical properties and heating effect was studied. Through the indirect tensile fatigue test, the effects of microwave heating time, healing time and damage degree on the self-healing efficiency of moisture-damaged asphalt mixture before and after microwave heating were studied based on the evaluation indexes of the fatigue life extension ratio and fatigue life recovery ratio. It is found that the optimal microwave heating time and optimal healing opportunity of OGFC-13 asphalt mixture with 5% ferrite are 120 s and 50% damage degree respectively. In addition, the longer the healing time, the better the healing effect, but the influence of the healing time is smaller compared with the heating time.

Active Microwave Thermography for Nondestructive Evaluation of Surface Cracks in Metal Structures

Detection of covered surface cracks in metal structures is an important issue in numerous industries. Various nondestructive testing (NDT) and evaluation techniques have been applied for this goal with varying levels of success. Recently, a technique based on the integration of microwave and thermographic NDT, herein referred to as active microwave thermography (AMT), has been considered for various applications. In AMT, electromagnetic energy is utilized for the thermal excitation, and the subsequent surface thermal profile of the structure/material under test is measured with a thermal camera. Utilizing electromagnetic energy allows the inspection to be tailored to the application through choice of frequency, polarization, and power level. It is shown that for metal with a dielectric-filled crack irradiated with an electric field (E-field) polarized perpendicular to the crack length, a propagating mode (TE10) is generated inside the crack, which causes dielectric heating to occur in the (filled) crack. In the particular case of study in this paper, based on the excitation power and the thermal camera sensitivity, the crack can be detected via an AMT inspection as long as the angle between the crack length and incident E-field is between 0° (perpendicular polarization) and ~65°. In addition, from the measured thermal contrast and signal-to-noise ratio, the optimum heating time is ~5–30 s for successful detection.

An Investigation of the Feasibility of the Organic Municipal Solid Waste Processing by Coking

In the context of transition to a circular economy, one of the strategic priorities is the development of technological innovations aimed at waste processing. In this study, the foundations have been developed for a low-temperature, environmentally safe method for efficient processing of organic municipal solid waste, which may be further applied for processing both municipal and industrial waste organics in order to obtain liquid products. The maximum yield of liquid products is ensured when conducting the coking of a mixture of organic waste with long residuum in the temperature range of 400–420 °C, with a heating rate of 5–70 °C/min, and with an optimal heating time to the coking temperature of 80 min. Recommendations on the use of the waste recycling products are given. The proposed process is consistent with the principles of circular economy and does not require external energy costs because the energy needed for the process is generated by burning the gas produced during the waste coking. The process does not produce emissions into the environment and, in combination with standard refining processes, can be used to obtain commercial petroleum products.

Sample injection of aromatic compounds from passive concentrators into multicapillary column by the thermal desorption method

At present, there is an increased interest in geochemical methods of searching for hydrocarbon deposits by detecting on the Earth's surface the scattering halos of hydrocarbons that migrated from those deposits, namely the aromatic hydrocarbons such as benzene, toluene, xylenes. The concentrations of the migrated hydrocarbons on the surface of the Earth are usually low and could only be detected at the threshold level of the gas analyzers. Therefore, for their registration, the preconcentration is applied, in particular, the passive preconcentration. For this purpose, the concentrators are used, which are laid at shallow depths in the explored area. The survey technology that is being developed by the authors uses the reusable concentrators in the form of hollow stainless-steel tubes with SE-30 siloxane-based sorbent applied on their inner surface. The concentrators placed in the analytical containers are laid in the ground for 1-2 days. The analysis of the samples from the concentrators is carried out on a portable multicapillary gas chromatograph in the field conditions. The current article is devoted to the development of a special device for the sample injection from the passive concentrators and the experimental determination of the optimal mode of thermal desorption sample injection from the concentrators into the multicapillary column. The original injection scheme is given, where the gas-dynamic isolation of the injection device camera and the multicapillary column during the concentrator heating and sample analysis is implemented; the optimum concentrator heating time and the optimum sample injection time are determined. Keywords: passive concentrators, thermal desorption sample injection, gas-dynamic isolation of the injection device and column DOI: http://dx.doi.org/10.15826/analitika.2019.23.3.003 (Russian) V.M. Gruznov 1,2,3 , M.N. Baldin 1 , A.O. Malysheva 1,3 1 Trofimuk Institute of Petroleum Geology and Geophysics of Siberian Branch of Russian Academy of Sciences, Koptug Avenue, 3, Novosibirsk, 630090, Russian Federation 2 Novosibirsk State University, Pirogova St., 2, Novosibirsk, 630090, Russian Federation 3 Novosibirsk State Technical University, Prospekt K. Marx Avenue, 20, Novosibirsk, 630073, Russian Federation

Isolation and characterization of macerated cellulose from pineapple leaf

Diverse renewable resources, especially those obtained from residual agricultural wastes, are being exploited to reduce the impact of environmental damage. This study presents a method to produce purified cellulose extracted from locally planted pineapple leaves (Ananas comosus). The cellulose was extracted by maceration pretreatment. The heating times were varied. This method is a simpler and more effective approach to delignify the pineapple leaf fibers compared with conventional chemical pulping and bleaching processes. The chemical composition of the cellulose was investigated according to TAPPI standards and by structural analyses, namely Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The results indicated that the hemicellulose and lignin were partially removed from the cellulose. Chemical analysis confirmed that the cellulose content increased from 25.8% (pineapple leaf fibers) to 70.9% (macerated cellulose). The optimum heating time was 3 h. However, XRD showed that the extracted cellulose had a higher crystallinity index than the initial pineapple leaf fibers. These results indicated that pretreatment via maceration has good potential applications in the production of macerated cellulose.

Characterization of Liquid Produced from Catalytic Pyrolysis of Mixed Polystyrene and Polyethylene Terephthalate Plastic

Plastic wastes accumulation increased each year in the environment. Plastics types are different such as polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polyvinyl chloride (PVC). In this paper, catalytic pyrolysis of Polystyrene and Polyethy terephthalate were studied to find the effect of PET on the pyrolysis of PS. The reaction took place in stainless batch tubular reactor to determine the effect of temperature and residence time. The maximum liquid products yield at optimum temperature and heating time(60 min) was 77% , 67.56%, 54% and 37.48% for PS, 10%PET + PS, 20%PET + PS and 30%PET + PS respectively. The liquid produced were characterized by GC-MS at optimum condition. The component of the liquid are styrene monemer, toluene, alpha-methylstyrene, 1,3 Diphenylpropane, 1-Phenylnaphthalene, 4-phenyl-1 butene. Styrene monomer was found to be the main product in the pyrolysis of PS, 10%PET+PS, 20%PET+PS and 30%PET+PS.The physical properties such as density, viscosity, and caloric value of the produced liquid was investigated ,the results was 0.9 g/cm3 ,2-3 Cp, and 40-45 MJ/kg respectively.

Influence of the Microwave Heating Time on the Self-Healing Properties of Asphalt Mixtures

This paper aims to evaluate the influence of the microwave heating time on the self-healing properties of fibre-reinforced asphalt mixtures. To this purpose, self-healing properties of dense asphalt mixtures with four different percentages of steel wool fibres were evaluated as the three-point bending strength before and after healing via microwave heating at four different heating times. Furthermore, the thermal behaviour of asphalt mixtures during microwave heating was also evaluated. With the aim of quantifying the efficiency of the repair process, ten damage-healing cycles were done in the test samples. In addition, self-healing results were compared with the fibre spatial distribution inside asphalt samples evaluated by CT-scans. Crack-size change on asphalt samples during healing cycles was also evaluated through optical microscopy. It was found that the heating time is the most influential variable on the healing level reached by the asphalt mixtures tested by microwave radiation. CT-Scans results proved that fibre spatial distribution into the asphalt mixtures play an important role in the asphalt healing level. Finally, it was concluded that 40 s was the optimum heating time to reach the highest healing levels with the lowest damage on the asphalt samples, and that heating times over 30 s can seal the cracks, thus achieving the self-healing of asphalt mixtures via microwave heating.

English

Green synthesis of silver nanoparticles (AgNPs) is non-toxic and eco-friendly than commonly used physicochemical methods. The study focuses on synthesis, characterization, antibacterial and antioxidant activity of AgNPs synthesized using aqueous extract of Moringa stenopetala (M. stenopetala) leaves. Optimum heating time required for the preparation of aqueous extract of M. stenopetala leaves was 15 min. It was found that 90 ml of 1 mM of silver nitrate solution and 15 ml of aqueous extract of M. stenopetala leaves were more favorable for maximum production of AgNPs with a yield of 97.14%. Ultraviolet-visible (UV-Vis) spectrum of synthesized AgNPs shows a peak at 412 nm. Fourier transform infrared spectroscopy (FTIR) spectral analysis indicated involvement of -C=O, -O-H, and -N-H in the formation of AgNPs. X-ray diffraction (XRD) pattern showed the face centered cubic (FCC) structure of AgNPs with average particle size of 11.44 nm. Synthesized AgNPs showed stronger antibacterial activity against Escherichia coli than Staphylococcus aureus and has better antioxidant activity than standard ascorbic acid. Key words: Silver nanoparticles (AgNPs), green synthesis, Moringa stenopetala.

Application of Neural Networks to the Optimization of the Thermal Treatment Process of Wood Materials

Abstract In this paper, a software system for 2-dimensional and 3-dimensional modeling of frozen and not frozen logs and prismatic wood materials is used as a basis for optimization of the thermal treatment process of such materials. Then, the dependence of the optimal heating time on various parameters is approximated by means of neural networks. This would allow a fast real-time computation of the optimal heating time instead of performing extensive numerical simulations of the model comprised of partial differential equations.

Step-heating infrared thermographic inspection of steel structures by applying least-squares regression

This paper reports the application of the least-squares regression method in the step-heating thermographic inspection of steel structures. The surface temperature variation of a slab with finite thickness during both the step-heating phase and the cooling-down phase is presented. A mild steel slab with holes of various depths and diameters is chosen as the specimen. The step-heating thermographic inspection experiments are carried out on the specimen with different heating times. The heating as well as the cooling-down phases are recorded with an infrared camera and are analyzed separately by linear regression of the double logarithmic temperature increase versus time plots. Three statistics of the linear regression, the slope, the coefficient of determination, and the F-test value, are used to create image maps according to the processing results. The signal-to-noise ratio of each map is calculated to evaluate the performance of the three imaging methods with different durations of heating time and cooling time. The results prove that the F-test value maps present a good performance for the sequences of the step-heating phase, while the slope maps present a good performance for the sequences of the cooling-down phase. The optimal heating time and cooling time for a steel structure are also concluded. The comparison with the results of the thermographic signal reconstruction (TSR) method proves that the least-squares regression method has better detectability and a higher inspection efficiency.

PEMANFAATAN GETAH BIDURI DALAM PRODUKSI ALBUMIN IKAN GABUS (Ophiocephalus striatus)

The Research about utilization of sap Biduri in the production of albumin fish cork (Ophiocephalus striatus). Has been done This research purposes to determine the ratio of sap Biduri to extract cork fish that produce the protein albumin with the highest yield and optimum heating time which produces the highest yield of the protein albumin. The study used a completely randomized design (CRD), which consists of the influence of the ratio of sap Biduri to extract protein and the effect of heating time Biduri to extract latex mixture. Each treatment is done twice to obtain 22 units of the experiment. The highest protein yield was obtained at a ratio of sap Biduri 3,0 : 30 and the heating time of 60 minutes at 53,43 %. The purity of the highest degree obtained at the optimum 50 minutes warm up period of 35.50 %.Keywords : Fish Cork, Biduri Protease enzyme, Protein yield of albumin, Albumin purity degree