scholarly journals Accurate Modeling of the Microwave Treatment of Works of Art

2019 ◽  
Vol 11 (6) ◽  
pp. 1606 ◽  
Author(s):  
Roberto Pierdicca ◽  
Marina Paolanti ◽  
Roberto Bacchiani ◽  
Roberto de Leo ◽  
Bruno Bisceglia ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Hot Spots ◽  
Software Tool ◽  
Microwave Treatment ◽  
Heating Power ◽  
Heating Process ◽  
Dielectric Characteristics ◽  
Works Of Art ◽  
Complex Shapes ◽  
Heating Treatment

The microwave heating treatment is a useful methodology and the disinfestation of works of art can also benefit from this approach. However, even if the microwave treatment is able to eliminate the pests that could damage the works of arts, it may nevertheless present some unexpected effects such as the presence of highly heated areas (hot spots) or areas with poor radiation due to particular shapes. To overcome this issue, we developed a mathematical model allowing predicting and monitoring tasks about the heating process. The prediction model has been developed into a software solution able to predict the distribution of heating power in objects to be treated, even of complex shapes, in order to define the exposure conditions, the time necessary to the processing, the power to be transmitted in the chamber and any repair or protection to cover the most sensitive areas. It can also predict the behaviour of irradiation in the presence of other entities such as nails or pests. The data to be provided for performing a simulation are: the geometry of the object, the shape of the infesting agent and their dielectric characteristics. As a result, we obtain the distribution of heating power and a software tool able to model and predict activities for cultural heritage treatments.

The measuring system for monitoring the microarc heating process during surface hardening of steel products

2021 ◽  
pp. 33-39
Author(s):  
Makar S. Stepanov ◽  
rina G. Koshlyakova
Keyword(s):  
Heat Treatment ◽  
Mathematical Model ◽  
Electric Current ◽  
Measurement Method ◽  
Sample Surface ◽  
Steel Sample ◽  
Measuring System ◽  
Heating Process ◽  
Carbon Powder ◽  
Measured Temperature

The accelerated heat treatment during steel products hardening technology has been investigated. The possibility of measuring the temperature of steel products by thermoelectric platinum-platinum-rhodium thermocouple under microarc heating conditions is analyzed. During the experiments, working junctions of two S-type thermocouples: working and standard, were coined into the sample surface at the same level. The free thermocouples ends were connected to a digital multimeter and a personal computer. It was determined that 5 factors affect the measurement results: the electric current strength in the circuit, carbon powder, calibration, number of repeated measurement cycles, and a thermocouple copy. When planning the experiment, the concept of conducting a step-by-step nested experiment was used. Variance analysis method was used to process the experimental results. The measurement method precision parameters were calculated: repeatability and reproducibility. A linear mathematical model linking the measurement method reproducibility index with the measured temperature value has been obtained. A linear mathematical model is obtained that relates the reproducibility index of the measurement method to the measured temperature value. A measuring system for the experimental determination of the temperature of a steel sample is proposed and its application is justified for different electric current densities on the sample surface and varying duration of microarc heating. The possibilities of selecting and controlling the microarc heating modes depending on the required temperature of the heat treatment of the steel product are determined.

Prediction of Deformations of Steel Plate by GEP in Forming Process

2012 ◽  
Vol 544 ◽  
pp. 268-273
Author(s):  
Lei Yang ◽  
Liang Gao
Keyword(s):  
Mathematical Model ◽  
Influencing Factors ◽  
Steel Plate ◽  
Heating Process ◽  
Forming Process ◽  
Line Heating ◽  
Main Method ◽  
Plate Deformation ◽  
Final Deformation

Line heating is the main method for forming compound curved shells of hull. The accuracy of final deformation and the productivity depend on the experience of the workers. To predict the plate deformation, the explicit mathematical model for deformation and the main influencing factors by FEA and GEP is established in this paper. The main influencing factors in line heating process were analyzed firstly. Then, 16 group deformation results of steel plate under the five main influencing factors were obtained by FEA. At last, the explicit mathematical model for deformation and the main influencing factors was established.

scholarly journals An Experimental Study on Bipolar Tissue Hemostasis and Its Dynamic Impedance

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Xiaoran Li ◽  
Roland Chen ◽  
Wei Li
Keyword(s):  
Minimal Invasive ◽  
Heating Power ◽  
Heating Process ◽  
Medical Procedure ◽  
Quality Prediction ◽  
Seal Failure ◽  
Vessel Sealing ◽  
Dynamic Impedance ◽  
Tissue Zone ◽  
Compression Level

Abstract Bipolar tissue hemostasis is a medical procedure where high frequency alternating current is applied to biological tissue for wound closing and blood vessel sealing through heating. The process is often performed with a set of laparoscopic forceps in a minimal invasive surgery to achieve less bleeding and shorter recovery time. However, problems such as tissue sticking, thermal damage, and seal failure often occur and need to be solved before the process can be reliably used in more surgical procedures. In this study, experiments were conducted to examine process parameters and the dynamic behavior of bipolar heating process through electrical impedance measurements. The effects of electrode compression level, heating power, and time are analyzed. Heating energy and bio-impedance are evaluated for quality prediction. Tissue sticking levels were correlated to the size of denatured tissue zone. It is found that tissue denaturation starts from the center of the heated region. Dynamic impedance reveals the stages of tissue hemostasis process. However, it is strongly affected by the compression level and heating power. Existing criteria for quality prediction and control using the heating energy and minimal impedance are not reliable. The size of denatured tissue zone can be predicted with the heating energy; however, the prediction is strongly dependent on the compression level. To avoid sticking, a low power and low compression level should be used for the same denatured tissue zone size.

Research on Heat Distribution in a Thermal Insulation Space and a Kind of Evaluation Involving Heat-Distribution and Valid Heating-Area

2013 ◽  
Vol 444-445 ◽  
pp. 1427-1433
Author(s):  
Hong Yang Jin ◽  
Zhi Hua Chen ◽  
Lang Li
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Standard Deviation ◽  
Thermal Insulation ◽  
Transfer Equation ◽  
Heating Process ◽  
Heat Distribution ◽  
Heat Transfer Equation ◽  
Heat Transmission

Considering that food always be spoiled in an oven, an analysis of the heat distribution of an object (pan) in a thermal insulation space has been done. The analysis based on the characteristics of heat transmission in an oven. A mathematical model is designed to illustrate the heating process. Specifically, in order to monitor the temperature of the object, pdetool in MATLAB is used to solve the heat transfer equation. Then to evaluate how an object performs in the oven, a method of standard deviation has been introduced. For the efficiency, valid heating area should also be considered. Thus an evaluation is made to choose a most preferring pan, which is balanced between heat distribution and valid heating area (number of pans). The experiment shows that shapes would devote much in performance. It is also demonstrated that there is a certain shape that can be most suitable to be a pan.

scholarly journals Microwave-assisted Enzymatic Hydrolysis to Produce Xylooligosaccharides from Rice Husk Alkali- soluble Arabinoxylan

2021 ◽  
Author(s):  
Wannaporn Klangpetch ◽  
Alisa Pattarapisitporn ◽  
Suphat Phongthai ◽  
Pannapapol Jaichakan
Keyword(s):  
Enzymatic Hydrolysis ◽  
Sodium Hydroxide ◽  
Microwave Heating ◽  
Rice Husk ◽  
Sugar Content ◽  
Microwave Treatment ◽  
Heating Process ◽  
Microwave Pretreatment ◽  
Microwave Assisted ◽  
Pretreatment Time

Abstract This study aimed to produce xylooligosaccharide (XOS) and arabino-xylooligosaccharide (AXOS) from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis and evaluate their prebiotic properties. The RH was pretreated by a microwave heating process at 140, 160 and 180°C for 5, 10, and 15 min to obtain crude arabinoxylan (AX). The results emphasized that increasing microwave pretreatment time increased sugar content. The crude AX was then extracted with 2% (w/v) sodium hydroxide at 25°C for 24 h. The obtained AX was then used as a substrate for XOS production by commercial xylanases. The results showed that the oligosaccharide produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. Interestingly, AXOS was also present in the oligosaccharide product. Furthermore, the oligosaccharides obtained were able to promote the growth of Lactobacillus spp. and to resist degradation more than 70% after exposure to simulated human digestion.

scholarly journals Experimental Investigation and Mathematical Modelling of Pressure Response for Steam Generator

2018 ◽  
Vol 7 (4.19) ◽  
pp. 960
Author(s):  
Mishaal A. AbdulKareem
Keyword(s):  
Mathematical Model ◽  
Time Delay ◽  
Water Temperature ◽  
Void Fraction ◽  
Steam Generator ◽  
Time Constant ◽  
Heating Power ◽  
Operating Pressure ◽  
Initial Water ◽  
Set Point

Cold startup of boiler is the process of boiler operation with water at ambient temperature and pressure with all intake and discharge valves are fully closed to permit fast development of pressure.  A mathematical model is developed to estimate the pressure response during cold startup of a perfectly insulated steam generator unit. A commercial type pressure switch is used in this unit to control and maintain the desired set point of the steam operating pressure. This mathematical model assume that the thermal properties of the supplied liquid water are temperature dependent. It is based on a novel Pressure Marching Technique that is coded using a FORTRAN language computer program. The maximum percentage error of (8.24 %) was obtained when comparing the predicted results of the mathematical model with the measured values obtained from the experimental test that was done using a (2 kW) electric steam generator unit with a volume of (30 litter) and maximum operating pressure of (8 bar). In addition, the same behavior of the predicted results was obtained when compared with results of a previously published article. It was found that the time constant of the pressure control system is directly proportional with its operating pressure set point and with the volume of the steam generator and its void fraction. A (50%) increase in the pressure set point will increase the time constant by (66.16%). Increasing the boiler volume by (166.667%) will increase the time constant by (166.677%) and increasing the boiler void fraction by (150%) will increase the time constant by (23.634%). The time constant is inversely proportional with the heating power of the steam generator. A (100%) increase in the heating power will decrease the time constant by (50%). The time constant is independent of the initial water temperature. Also, it was found that the time delay to start water evaporation is directly proportional with the volume of the steam generator. A (166.667%) increase in boiler volume will increase the time delay by (166.65%). The time delay is inversely proportional with the initial water temperature and with the heating power and void fraction of the steam generator. A (38.889%) increase in the initial water temperature will decrease the time delay by (8.882%). Increasing the heating power by (100%) will decrease the time delay by (50%) and increasing the boiler void fraction by (150%) will decrease the time delay by (16.665%). The time delay is independent on the operating pressure set point.  

scholarly journals MICROWAVE TREATMENT OF MATERIALS IN LOW PRESSURE

2019 ◽  
Author(s):  
Parosa Ryszard ◽  
Andrzej Brożyński ◽  
Piotr Grześkowiak ◽  
Krzysztof Kowalczyk ◽  
Marek Natoński ◽  
...  
Keyword(s):  
Treatment Time ◽  
Low Pressure ◽  
Microwave Treatment ◽  
Laboratory Scale ◽  
Microwave Drying ◽  
Microwave Cavity ◽  
Industrial Scale ◽  
Heating Process ◽  
Universal System ◽  
Scale Unit

Ryszard Parosa, Andrzej Brożyński, Piotr Grześkowiak, Krzysztof Kowalczyk, Marek Natoński, Piotr Ziętek and Janusz Żytkiewicz PROMIS-TECH Poland Keywords: microwave treatment, low pressure heating, microwave drying Uniquely favourable characteristics of biological product can be obtained through the use of the microwave method in vacuum heating process. Microwave-vacuum drying is superior to other methods in terms of dried products' structure, flavour, colour and biological active compounds contents. But applications of such a methods seems to be much wider: drying of fruits and vegetables for consumption, drying of herbs for extraction of valuable biological compounds, for modification of seed structure (sunflowers seeds, pumpkin seeds), for pasteurisation etc. A universal system was designed for testing such processes in laboratory scale and several industrial scale system have been developed. Process of thermal treatment can be carried out with plastic drum installed inside of multi-mode microwave cavity and cavity which is connected by microwave line with reflectometer and circulator - to microwave generator. In laboratory unit generator 2.45 GHz with controlled power (from 50W to 800W) was applied. System was equipped with vacuum pump with pressure control and is controlled by computer. Most important technical parameters, like: microwave power, time of treatment, pressure inside of drum, temperature of steam – are controlled and  recorded. Laboratory scale unit is shown below.     Basing on laboratory scale test several technologies in industrial scale was developed. Industrial scale unit equipped with 8 generators of 3 kW (2.45 GHz) was constructed and for last 8 years has been successfully used for “production” of crispy chips which are now popular in Polish marked. Exemplary industrial scale installation is shown in photo below.  Multi – drum microwave drier.   Two cavity microwave  industrial drier    Another system for modification od seed is now constructed – ordered by big industrial producer of batons and sweet snacks. Process will be carried our inside of dielectric drum in low pressure and reactor will be equipped with 8 generators of 3 kW (2.45 GHz). Treatment time will be reduced to 3-4 minutes and next material (seeds) will be cooled down. Last project which now realized is connected with drying of wood flour applied in composite material production. System will work continuously with two airlocks and with  dielectric drum and will be connected with 4 microwave generators (3 kW, 2.45 GHz). In next step planed installation will be equipped with microwave high power generator ca. 60 kW with frequency 915 MHz. 

scholarly journals Self-heating behaviour of low moisture content particles—modelling the basket-heating of solid particles and some aspects of the cross over behaviour using milk powder as an example

2001 ◽  
Vol 43 (1) ◽  
pp. 165-181 ◽  
Author(s):  
Xiao Dong Chen
Keyword(s):  
Mathematical Model ◽  
Milk Powder ◽  
Food Product ◽  
Solid Material ◽  
Solid Particles ◽  
Heating Process ◽  
Self Heating ◽  
Sample Water ◽  
The Cross ◽  
Further Development

AbstractSelf-heating in packed paniculate that is exothermically reactive is a major cause of fire and explosion in the powder industry. This study is focused on part of the Auckland development of a mathematical model dealing with this hazardous process in industry using milk powder as an example. Milk powder is a primary powdered food product around the world.An update of the detailed mathematical model is given here, and predictions are made using the model to simulate the basket-heating behaviour of a milk powder in the laboratory (so the model can thus be validated). Basket heating in an oven is a standard laboratory technique for measuring the exothermic reactivity of a solid material.After a favorable comparison with the laboratory results, several aspects of basket-heating were investigated with a view to further improving the technique. Firstly, the model was used to explore the effect of elevated ambient humidity and initial sample water content upon the heating process in the basket. Secondly, the model was used to explore the cross over phenomenon which is related to a novel procedure for measuring activation energy and exothermicity (that is, the Crossing-Point-Temperature (CPT) method, which is a new version of the basket heating technique). The predictions together with the experimental evidence show that the reaction kinetics obtained using the Heat Release (HR) method (another version of the basket heating technique well published in the literature) may not be correct, especially for those measured at elevated oven temperatures and for larger basket sizes. Thirdly, simulations were performed to illustrate that the CPT phenomenon does not just occur at the center of the basket but also occurs everywhere else in the sample. This can become a significant advantage for further development of the CPT method in terms of reducing experimental duration and improving reproducibility.

A Study of Predictive Control of Energy-Saving of Heating Process

2011 ◽  
Vol 328-330 ◽  
pp. 1810-1813
Author(s):  
Xue Li Zhu ◽  
Shu Xian Zhu ◽  
Sheng Hui Guo
Keyword(s):  
Control System ◽  
Error Correction ◽  
Energy Saving ◽  
Real Time ◽  
Predictive Control ◽  
Control Method ◽  
Heating System ◽  
Heating Power ◽  
Heating Process ◽  
Power Station

This paper presents a predictive control method of heating system of heating power station. Firstly, the forecast of heating load is introduced using time series analysis, and the obtained result is used as an energy-saving initial value of predictive control system. Secondly, model simplification method is given and immediate control law is derived, the predictive model order is decreased from N to n. Simplification model satisfies the demand of real-time property of the control system. Thirdly, predictive error correction is used to replace error correction to implement the correction of optimum control of the system, which can improve adaptability and robustness of the system. Finally, simulation of heating system of heating power station is conducted and the results prove that the algorithm is effective in ensuring real-time control, improving tracking and robustness property.

Based on the Repetitive Controller for Induction Heating Power Supply

2013 ◽  
Vol 310 ◽  
pp. 470-476
Author(s):  
Yue Feng ◽  
Mei Qi Liu ◽  
Mei Xia Qiao ◽  
Jie Wang
Keyword(s):  
Induction Heating ◽  
Control Strategy ◽  
Power Supply ◽  
Heating Power ◽  
Heating Process ◽  
Static Properties ◽  
Output Quality ◽  
Combined Control ◽  
Electromagnetic Induction Heating ◽  
Repetitive Controller

According to the electromagnetic induction heating power supply control system, puts forward a kind of proportion, integral, differential regulator with repetitive controller combined control strategy, in order to improve the heating process of the power supply output quality. Based on this control strategy, gives the repetitive controller each part parameters of the detailed design scheme and proportion, integral and differential controller coefficient; Construction of compensator Q(z) and S(z) , the introduction of zero phase shift Notch function, effectively inhibit PWM-type induction heating power supply output voltage harmonic interference. To carry out the simulation experiment, the results show that the proposed controller can guarantee that the system has better dynamic and static properties, error convergence rate is greatly improved.

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