characteristic dimension
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Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1415
Author(s):  
Radosław Winiczenko ◽  
Agnieszka Kaleta ◽  
Krzysztof Górnicki

The aim of the study was to estimate the optimal parameters of apple drying and the rehydration temperature of the obtained dried apple. Conducting both processes under such conditions is aimed at restoring the rehydrated apple to the raw material properties. The obtained drying parameters allow the drying process to be carried out in a short drying time (DT) and at low energy consumption (EC). The effect of air velocity (vd), drying temperature (Td), characteristic dimension (CD), and rehydration temperature (Tr) on rehydrated apple quality was studied. Quality parameters of the rehydrated apple as: color change (CC), mass gain ratio (MG), solid loss ratio (SL), volume gain ratio (VG) together with DT and EC were taken into consideration. The artificial neural network was used for modeling of rehydrated apple quality parameters, DT, and EC. A multi-objective genetic algorithm was developed in order to optimize parameters of the drying and rehydration processes. The simultaneous minimization of CC, SL, DT, EC, and the maximization of MG and VG were considered with the following drying and rehydration processes parameters: Td: 50–70 °C, vd: 0.01–2 m/s, Tr: 20–70 °C. The best solution has been found at drying temperature 56.1 °C, air velocity 1.3 m/s, characteristic dimension 2.0 mm, and rehydration temperature 59.2 °C. This apple drying and rehydration resulted in MG = 3.51, SL = 0.57, VG = 4.77, CC = 11.2, DT = 5.4 h, EC = 159.8 GJ/kg. The parameters of apple drying and rehydration processes can be recommended for the industry application.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qian Xu ◽  
Zhong-Qi Wang

To compare the damage zones of spherical and cylindrical charges in rock and soil, a quasistatic spherical model was established to predict the characteristic dimension of the cavity. The results indicated that the damage zones of cylindrical charges were larger than those of spherical charges. Furthermore, the cavity development of two charges with different shapes was obtained by numerical simulation, and a comparison of the prediction results between the quasistatic model and numerical simulation was made. The comparison showed that the model could predict the damage zones exactly and faster than numerical simulation. Ultimately, the influence of explosions and soil media was discussed by the quasistatic model. It was observed that larger damage zones were generated by smaller values of the product of pressure and exponential expansion. However, the influence of soil media was complex, and larger damage zones were usually generated by the harder soil media.


Author(s):  
Г.А. Шнеерсон ◽  
А.А. Парфентьев ◽  
В.В. Титков ◽  
С.И. Кривошеев ◽  
А.Д. Лагуткина ◽  
...  

The efficiency of using a diamagnetic screen with inertial retention in a non-destructive quasi-force-free magnet of a small volume (with a characteristic dimension about 10 cm^3 ) for generating a superstrong magnetic field with a pulse duration of about 10 µs is shown. A configuration of the magnet was developed, in which the end part of the winding is balanced due to the fact that the screen virtually does not move during the discharge. Mechanical stresses in the winding were calculated, and it was demonstrated that mechanical strength of the winding can be ensured in a field with magnetic flux density up to 100T. Calculations of the heating of the winding were performed and the possibilities of its reduction to an acceptable level are indicated.


2020 ◽  
Vol 14 (3) ◽  
Author(s):  
Y Verkhivker ◽  
E. Altman ◽  
A. Palamarchuk ◽  
N. Kushnyrenko ◽  
S. Patyukov

The purpose of this research was to study the modes of  heating different types of plant raw materials in model technological environments that imitate the blanching of raw materials under factory conditions. The research aimed at expanding the range of canned products made from fruit and vegetables. To this end, new methods were searched for, in addition to the existing ones, allowing heating various plant raw materials and increasing the energy efficiency of canned fruit and vegetables production. Saturated water steam was selected as the treatment medium. The experimental studies included determining the volume-average  temperature of the fruit layer in the container. A pulse method of supplying the heating media has also been investigated. It allows using the inertial properties of raw materials and significantly reducing the expenditure of the heating media.  The objects selected for study were various species of pomes and drupes, in particular, apples, plums, cherries, sweet cherries, as well as a vegetable crop of the gourd family, or Cucurbitaceae. The following characteristics have been studied: the dynamics of heating individual fruit and vegetables in the saturated water steam environment at atmospheric pressure; the dependence of the heating and cooling rates of individual fruit and vegetables on the geometric index; the dependence of the heating rate of individual fruit and vegetables on the value of the characteristic dimension; the dependences of changes in the volume-average temperature of the fruit layer on the duration of treatment with saturated water steam. It has been established that the volume-average temperature in the centre of a fruit is also influenced by the shape of the fruit itself. To characterise the anomalous shapes of plant raw materials, the geometric index G has been calculated. This index characterises the elliptical shape of a fruit, and allows determining parameters in two mutually perpendicular planes. Also, to compare fruit of the elliptical and the spherical shapes, a special concept of characteristic dimension was used, which is applicable to fruit of different shapes. The experimental data on the change in the dependences of the heating and cooling rates of individual elliptical fruit have been analysed. The analysis has shown that the size of a fruit significantly affects the volume-average temperature in the fruit layer. It has been suggested to use pulsed heating of the fruit layer with saturated  water steam, which will appreciably increase the energy efficiency of production due to a significant reduction in heating media consumption


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3016 ◽  
Author(s):  
Marco Moscatelli ◽  
Claudia Comi ◽  
Jean-Jacques Marigo

Among the attractive properties of metamaterials, the capability of focusing and localizing waves has recently attracted research interest to establish novel energy harvester configurations. In the same frame, in this work, we develop and optimize a system for concentrating mechanical energy carried by elastic anti-plane waves. The system, resembling a Fabry-Pérot interferometer, has two barriers composed of Locally Resonant Materials (LRMs) and separated by a homogeneous internal cavity. The attenuation properties of the LRMs allow for the localization of waves propagating at particular frequencies. With proper assumptions on the specific ternary LRMs, the separation of scales (between the considered wave lengths and the characteristic dimension of the employed unit cells) enables the use of a two-scale asymptotic technique for computing the effective behavior of the employed LRMs. This leads to a complete analytic description of the motion of the system. Here we report the results achieved by optimizing the geometry of the system for obtaining a maximum focusing of the incoming mechanical energy. The analytic results are then validated through numerical simulations.


2020 ◽  
Vol 24 (1) ◽  
pp. 61
Author(s):  
Zubaedi Zubaedi

The article examines 2013 curriculum (K-13) implementation of Islamic Religious Education (PAI) subject towards paradigm of scientific and characteristic. There were two issues to be discussed: First, how do the teachers plan the K-13 implementation? Second, how do the teachers implement the learning patterns of PAI subject according to K13? Qualitative approach was employed by understanding related-person performance in certain situation naturally, or without influenced by surrounding. In qualitative study analysis, inductive method was applied by overlooking initial hypothesis, while exploring the patterns, forms, and themes in examining data systematically. The present study found that the implementation of K-13 in PAI subject at State Vocational High School (SMKN) 2 Bengkulu run systematically and programmatically. The K-13 program was began with conducting training, designing program for annually, every semester, monthly, and daily, as well as for remedial program. The learning process of K-13 was implemented through introductory, core, and closing activities. The K-13 implementation indicated scientific-based learning, such as inquiry, discovery, problem solving, and video analysis. This implementation revealed that benefit to build religious character.


2019 ◽  
Vol 2 (2) ◽  
pp. 203-208
Author(s):  
Yury Kolesnikov ◽  
Ruslan Beysembaev

The results of physical modeling show that the influence of boundary roughness on its reflectivity depends on the ratio of roughness characteristic dimension and wavelength. The boundary roughness leads to a decrease in the effective reflection coefficients at subcritical and to their increase at supercritical angles of incidence. A change in the azimuth of the plane of incidence with respect to the roughness direction appreciably affects the reflection coefficients only at supercritical angles.


2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Jianwei Sun ◽  
Wenrui Liu ◽  
Jinkui Chu

This paper presents a synthesis method for the open path generation of a four-bar mechanism using the Haar wavelet. The synthesis method utilizes the wavelet transform and normalization to extract the wavelet output feature parameters (WOFP) of the open path. Analysis of the WOFP reveals a particular characteristic: for the same four-bar mechanism, not only do variations of the mechanism origin and angles and the proportional scaling of the linkage lengths have no influence on the details of the WOFP but the same holds true for the position of the point that generates the coupler curve. Based on this finding, a numerical atlas database comprises 192,596 groups of basic dimensional types was established and a method of matching recognition was proposed as well. According to the internal relationship of the wavelet characteristic dimension parameters (WCDP), the actual mechanism parameter values and position parameters of an objective four-bar mechanism can be calculated. Four examples are presented to verify the accuracy and practicality of the proposed theory.


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