Description of the Convective Air-Drying of a Food Model by Means of the Fractal Theory

2003 ◽  
Vol 9 (3) ◽  
pp. 207-213 ◽  
Author(s):  
P. J.J. Chanona ◽  
B. L. Alamilla ◽  
R. R.R. Farrera ◽  
R. Quevedo ◽  
J. M. Aguilera ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Fractal Theory ◽  
Drying Kinetics ◽  
Linear Stage ◽  
Equilibrium Conditions ◽  
Drying Time ◽  
Air Drying ◽  
Three Stages ◽  
Food Model

A slab-shaped model food prepared using glucose solutions and agar as jellifying agent was subjected to drying in an experimental drier. Drying kinetics and surface temperature (ST) distribution along drying were evaluated. When fractal analysis was applied to ST distributions it was possible to observe three stages: the first one, at the beginning of the process, was very short and could not be associated with a fractal dimension. The second one, by far the longest, had a constant value of the fractal dimension of the ST distribution and towards the end of the process, as temperature of the surface of the material tended to homogenise, a final linear stage was found which corresponded to equilibrium conditions. Images of the slab along drying were recorded and showed an increasing heterogeneous appearance as drying proceeds. Grey level intensity plots corresponding to these images also showed an increasing irregularity (higher values of fractal dimension) with drying time. Fractal analysis probed to be a useful tool for describing drying kinetics and for characterising images of samples subjected to dehydration.

scholarly journals Review about the Application of Fractal Theory in the Research of Packaging Materials

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 860
Author(s):  
Qingshan Duan ◽  
Jiejie An ◽  
Hanling Mao ◽  
Dongwu Liang ◽  
Hao Li ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Fractal Theory ◽  
Inorganic Materials ◽  
Packaging Materials ◽  
Analysis Method ◽  
Characteristic Parameters ◽  
Fractal Characteristic ◽  
Fractal Characteristics ◽  
The Relationship

The work is intended to summarize the recent progress in the work of fractal theory in packaging material to provide important insights into applied research on fractal in packaging materials. The fractal analysis methods employed for inorganic materials such as metal alloys and ceramics, polymers, and their composites are reviewed from the aspects of fractal feature extraction and fractal dimension calculation methods. Through the fractal dimension of packaging materials and the fractal in their preparation process, the relationship between the fractal characteristic parameters and the properties of packaging materials is discussed. The fractal analysis method can qualitatively and quantitatively characterize the fractal characteristics, microstructure, and properties of a large number of various types of packaging materials. The method of using fractal theory to probe the preparation and properties of packaging materials is universal; the relationship between the properties of packaging materials and fractal dimension will be a critical trend of fractal theory in the research on properties of packaging materials.

scholarly journals Microwave and steam blanching as pre-treatments before air drying of Moringa oleifera leaves

2020 ◽  
Vol 51 (4) ◽  
pp. 200-208
Author(s):  
Ernest Ekow Abano ◽  
Robert Sarpong Amoah ◽  
Catherine Mbabazi
Keyword(s):  
Microwave Power ◽  
Moringa Oleifera ◽  
Drying Kinetics ◽  
Drying Time ◽  
Air Drying ◽  
Moringa Oleifera Leaves ◽  
Pre Treatment ◽  
Microwave Time ◽  
Drying Conditions ◽  
Short Time

The objective of this work was to identify the optimal drying conditions to produce better quality dried Moringa oleifera leaves with the best drying kinetics using microwave and steam blanching pre-treatments prior to hot air drying. For this purpose, the effect of microwave power, microwave time, steaming time, and air temperature on drying kinetics and quality of Moringa leaves was evaluated using the response surface methodology. In order to achieve a moisture content of 8.0% kg H2O/kg dry matter, the optimal conditions identified were a steaming time of 2.58 min (2 min 35 sec) prior to air drying at 70°C and a microwave power of 270 W for 3 min, followed by air drying at 70°C. At this optimal condition, a confirmation test for steam-assisted air drying gave a drying time (DT) of 53 min, ascorbic acid (AA) of 2.49 mg/g, and the antioxidant activity (AOA) of 67.244% inhibition. For microwave-assisted air drying, the confirmation experiment gave a DT of 43 min, AA of 2.699 mg/g, and AOA of 74.46% inhibition. Both pre-treatments before air drying followed a falling rate drying period at the initial stages and later a constant rate drying period. Our results showed that microwave blanching should be considered as a pre-treatment in industrial production of Moringa leaves to produce better quality dried products in a relatively short time.

scholarly journals Fractal analysis for osteoporosis: a likelihood ratio approach

2010 ◽  
Vol 58 (3) ◽  
pp. 119-130 ◽  
Author(s):  
Jessica B. Lepschy ◽  
Milan Stehlík ◽  
Mária Minárová
Keyword(s):  
Fractal Dimension ◽  
Likelihood Ratio ◽  
Fractal Analysis ◽  
Medical Diagnosis ◽  
Fractal Theory ◽  
Real Data ◽  
Analytical Tool ◽  
Ratio Approach ◽  
Insight Into

Based on the traditional fractal theory and on the paper of Stehlík, (2009) the range of fractal dimension of osteoporosis vertebras is analysed. First we give an insight into the field of fractals and the usa­ge of fractals in medicine. After this we show how the analytical tool of Stehlík, (2009) may be applied to the osteoporosis vertebras. It turns out that the used method can be applied very well and that it could help with medical diagnosis. Real data example illustrates the methods discussed.

scholarly journals Effect of Freeze-Thaw Cycles on Juice Properties, Volatile Compounds and Hot-Air Drying Kinetics of Blueberry

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2362
Author(s):  
Lin Zhu ◽  
Xianrui Liang ◽  
Yushuang Lu ◽  
Shiyi Tian ◽  
Jie Chen ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Drying Kinetics ◽  
Soluble Solids ◽  
Hot Air Drying ◽  
Fresh Sample ◽  
Drying Time ◽  
Air Drying ◽  
Freeze Thaw ◽  
Hot Air ◽  
Kinetics Of

This paper studied the effects of freeze-thaw (FT) cycles on the juice properties and aroma profiles, and the hot-air drying kinetics of frozen blueberry. After FT treatment, the juice yield increased while pH and total soluble solids of the juice keep unchanged. The total anthocyanins contents and DPPH antioxidant activities of the juice decreased by FT treatments. The electronic nose shows that FT treatments significantly change the aroma profiles of the juice. The four main volatile substances in the fresh juice are (E)-2-hexenal, α-terpineol, hexanal and linalyl formate, which account for 48.5 ± 0.1%, 17.6 ± 0.2%, 14.0 ± 1.5% and 7.8 ± 2.7% of relative proportions based on total ion chromatogram (TIC) peak areas. In the FT-treated samples, the amount of (E)-2-hexenal and hexanal decreased significantly while α-terpineol and linalyl formate remained almost unchanged. Repeated FT cycles increased the ethanol content and destroyed the original green leafy flavor. Finally, the drying kinetics of FT-treated blueberries was tested. One FT treatment can shorten the drying time by about 30% to achieve the same water content. The Deff values of the FT-treated sample are similar, which are about twice as large as the value of the fresh sample. The results will be beneficial for the processing of frozen blueberry into juice or dried fruits.

scholarly journals Stochastic Fractal Dimension Image

2009 ◽  
Author(s):  
Nicholas J. Tustison ◽  
James Gee
Keyword(s):  
Brownian Motion ◽  
Fractal Dimension ◽  
Fractional Brownian Motion ◽  
Fractal Analysis ◽  
Medical Image ◽  
Fractal Theory ◽  
Motion Model ◽  
Edge Enhancement ◽  
Brownian Motion Model ◽  
Medical Image Classification

Fractal analysis for medical image classification and analysis was introduced in cite{Chen1989}. According to the authors, when viewed as an intensity surface, Mandelbrot's fractal theory provides an informative framework for characterizing such a surface. Using the fractional Brownian motion model, the authors provide an algorithm for converting a scalar image to a fractal dimension image for classification purposes or edge enhancement. This submission constitutes a report on the ITK implementation of this algorithm.

Influence of Microwave Osmotic Dehydration Pre-Treatment on the Second Stage of Air-Drying Kinetics of Apples

2011 ◽  
Vol 7 (3) ◽  
Author(s):  
Elham Azarpahzooh ◽  
Hosahalli S. Ramaswamy
Keyword(s):  
Energy Savings ◽  
Osmotic Dehydration ◽  
Sucrose Concentration ◽  
Drying Kinetics ◽  
Drying Time ◽  
Air Drying ◽  
Second Stage ◽  
Freeze Dried ◽  
Pre Treatment ◽  
Kinetics Of

The effect of microwave-osmotic dehydration pre-treatment under continuous flow medium spray (MWODS) conditions on the second stage air-drying kinetics of apple (Red Gala) cylinders was evaluated. MWODS pre-treatment was carried out using a response surface methodology involving 5-levels of sucrose concentration (33-66.8°B), temperature (33-66.8°C) and contact time (5-55 min). Drying time and coefficient of moisture diffusion (Dm) and coefficient of moisture infusion (Im) during rehydration were evaluated as responses and the results were compared with their air-dried (AD) (worst scenario) and freeze-dried (FD) (best scenario) counterparts without the osmotic treatments. The diffusion and infusion coefficients were based on the solution of Fick's diffusion model. Empirical models developed for all response variables were significant (P ? 0.001) and the lack of fit was not significant (P > 0.05). MWODS pre-treatments significantly influenced the Dm values and reduced the air-drying time of apples by 30-65 percent in comparison with untreated apple thereby providing opportunity for better energy savings. On the other hand, the values of Im during the rehydration process were highest for the freeze-dried samples followed by apples air-dried after MWODS treatment, and the least for the untreated air-dried samples.

scholarly journals Evaporative Cracking Characteristics of the Embankment Soil Affected by the Saline Concentration

2022 ◽  
Vol 2022 ◽  
pp. 1-9
Author(s):  
Jiawei Liu ◽  
Yingzhi Xia ◽  
Hui Li ◽  
Guoping Hu ◽  
Mingming Hu
Keyword(s):  
Fractal Dimension ◽  
Moisture Content ◽  
Water Evaporation ◽  
Evaporation Process ◽  
Residual Moisture ◽  
Drying Time ◽  
Equilibrium Evaporation ◽  
Cracking Characteristics ◽  
Three Stages ◽  
Evaporation Stage

Embankment soil affected by saline can not only cause roadbed settlement, frosting, and road cracks but also cause corrosion and cracking of roadbed pipelines, which seriously affects the stability of the road. Water evaporation and dry cracking of the saline soil mainly cause soil swelling, poor water stability, and corrosive characteristics of the embankment soil. In this study, the evaporative cracking characteristics of soil with different saline concentrations were investigated. The results showed that the moisture content decreased linearly with the drying time in the early evaporation process, subsequently decreased slow down in the mid-term evaporation, and finally become got and remain a residual moisture content, which are 46.39%, 44.05%, 42.70%, and 40.27% with the increase of the saline concentration. The evaporation process with different saline concentrations in the soil can be divided into three stages: uniform evaporation stage, slow down evaporation stage, and equilibrium evaporation stage, which was consistent with the moisture content change. With the development of the drying time, the cracks gradually appeared on the soil surface, gradually deepened in the soil, and expanded the crack network. The development of cracks can be divided into three stages: the cracking preparation stage, the crack development stage, and the crack stable stage. The cracking began at high evaporation rate under high saline concentration, and the fractal dimension remained stable under similar saline concentration. The fractal dimension was gradually increased with the decrease of the moisture content and the increase of the saline concentration, respectively. The soil began to crack with larger moisture under high saline concentration. The drying cracks in the nature were consistent with the configuration of the cracks formed in the experimental results.

Hot-air Drying Kinetics of Yam Slices under Step Change in Relative Humidity

2016 ◽  
Vol 12 (8) ◽  
pp. 783-792 ◽  
Author(s):  
Hao-Yu Ju ◽  
Qian Zhang ◽  
A.S. Mujumdar ◽  
Xiao-Ming Fang ◽  
Hong-Wei Xiao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Weibull Model ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Rehydration Ratio ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air

Abstract The drying kinetics and mathematical modeling of hot-air drying of yam slices were investigated under two-stage relative humidity (RH) control strategy with 60 °C and 1.5 m/s as its constant drying temperature and air velocity, respectively. Results indicate high RH in the initial stage results in high sample’s temperature that enhances water diffusion in the falling rate drying period. Within the scope of current work, change in RH in the later drying period has insignificant influence on sample’s temperature rise while low RH can accelerate the drying rate. Compared to drying at constant 20 % RH at the same drying air temperature, the drying strategy of using 40 % RH over the first 15 min and then lowing to 20 % RH for the remainder time yields a shorter drying time. Weibull model adequately described the moisture content variation with time for all experiments with the scale parameter ranging from 105.02 to 122.38 min and the values of shape parameters from 0.988 to 1.183. The effective moisture diffusivity determined from the Weibull model varied from 2.032 to 2.610×10−8 m2/s. The rehydration ratio increased as the overall drying time was reduced. Microstructure examination shows that higher RH in the initial drying stage can lead to a more porous microstructure which enhances drying, while fast drying rate in the initial drying period generates a crust layer which hinders drying.

scholarly journals Drying Kinetics, Grinding Characteristics, and Physicochemical Properties of Broccoli Sprouts

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 97 ◽  
Author(s):  
Dariusz Dziki ◽  
Ewa Habza-Kowalska ◽  
Urszula Gawlik-Dziki ◽  
Antoni Miś ◽  
Renata Różyło ◽  
...  
Keyword(s):  
Color Difference ◽  
Physicochemical Characteristics ◽  
Drying Kinetics ◽  
Drying Time ◽  
Air Drying ◽  
Drying Temperature ◽  
Broccoli Sprouts ◽  
Freeze Dried ◽  
Kinetics Of ◽  
Total Color Difference

In this study, we studied the drying process, grinding characteristics and physicochemical characteristics of broccoli sprouts (BS). The seeds of broccoli were germinated at 20 °C for 3 and 6 days. Then, the seeds were air- and freeze-dried, and the Page model was used for prediction of drying kinetics of broccoli sprouts. It was observed that the drying time of BS decreased about twofold as the air-drying temperature increased from 40 to 80 °C. An increasing the air-drying temperature from 40 to 80 °C decreased the drying time by approximately twofold. Freeze-drying of sprouts took the longest drying time. Germination of seeds significantly decreased the value of grinding energy requirements, and the ground sprouts exhibited a different grinding pattern in comparison to ground non-germinated seeds. In terms of color parameters, the highest lightness and yellowness were found for freeze-dried sprouts. Redness and yellowness of sprouts increased with an increase in the air-drying temperature. The lowest total color difference was obtained for the freeze-dried sprouts. Higher drying temperature resulted in lower total phenolics content (TPC) and decreased antioxidant activity (AA). The highest TPC and AA were observed in air-dried sprouts (40 °C) and freeze-dried sprouts after 6 days of germination.

scholarly journals The Effect of Vacuum Impregnation Pretreatment on Air-Drying Kinetics of Pears

2020 ◽  
Vol 8 (11) ◽  
pp. 2248-2254
Author(s):  
Şeyma Uysal ◽  
Fikret Pazır
Keyword(s):  
Effective Diffusion ◽  
Solution Concentration ◽  
Drying Kinetics ◽  
Vacuum Impregnation ◽  
Drying Process ◽  
Drying Time ◽  
Air Drying ◽  
Pyrus Communis L ◽  
Experimental Values ◽  
Kinetics Of

The aim of this study was to examine the drying kinetics of pears (Pyrus communis L.) with and without vacuum impregnation and under the different temperature by using tray dryer. Vacuum impregnation were applied to the the pears (15 mm thickness, 65 mm outer and 20 mm inner dimensions respectively) with the conditions of 50⁰ Brix impregnation solution concentration, 225 mbar vacuum pressure and 45 min vacuum time. Drying process was carried out at temperatures of 55, 65 and 75°C. Drying time of non-vacuum impregnated pears was determined 640, 500 and 340 min and vacuum impregnated pears was determined 700, 540 and 560 min respectively. Page, Exponential, Henderson and Pabis, Diffusion Approach were examined for testing the drying kinetics. Experimental values are in accordance with the expected values resulted Page and Difussion models of with and without vacuum impregnated pears. Effective diffusion coefficient (Deff) was varying 2.74×10-11 to 7.31×10-11 m2/s. m2/s with respect to the drying temperatures. The activation energy for the non-vacuum impregnated and vacuum impregnated pears was 32.93 kJ / mol and 24.25 kJ / mol, respectively.

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