Microwave drying compared to conventional hot air drying has many benefits to apply in food drying processes such as volumetric heating, high thermal efficiency, shorter drying time and improved product quality. In conventional microwave drying method, a fixed microwave power was used during the drying process. However, the water of the product evaporated and mass of product decreased over the time that resulted in microwave power density (MPD) increasing during the drying process. Increasing the power density, especially at the end of the process, sharply increased the product temperature. High temperature of products led to the deterioration of the product quality. Most research used variable microwave power program for preventing the risk of overheating and charring of product. The evaporation of the water causes the shrinkage of product. Therefore, many studies have used machine vision for measuring the shrinkage and this technology has been used in modeling and predicting the MC.

The fresh potato samples (Solanum tuberosum cv. Santana) with 83% (w.b.) of initial MC were sliced into the chips of 5mm thickness. The developed drying systems consisted of microwave oven, lighting unit and imaging unit, temperature sensor, microwave power adjusting unit and a data acquisition unit (DAQ). A LabVIEW (V17.6, 2017) program was developed to integrate all measurements and adjusting the microwave power during the drying process. In this study, two sets of experiment with different aims have done. The first set of experiments was used for calculating the shrinkage by developed image processing algorithm and MC by offline mass measurement and then data sets were used to investigate the artificial neural networks (ANNs). The second set was used for evaluating the reliability of investigating models. The experiments, in the first set, were done with 8, 4 and 2.67 W g-1. In the variable mode, the power varied in two/three steps with respect to the MC of samples during the drying process. Second set of experiments was done in two variable and constant power modes with 5 and 3 W g-1. An image processing algorithm was developed to measure the shrinkage of potato slice during the drying process. In this study the feed forward ANN with back propagation algorithm was used. Two structures of ANN were used for modeling of MC. In the first model time and power density and the second model shrinkage and power density were used as input. Also moisture ratio was used as an output parameter in two models.

The obtained results indicated that for the first model the ANN with 2-3-1 structure had better results than others structures. This structure had 0.0713, 0.0337 and 0.0640 of RMSE and 0.9764, 0.9973 and 0.9800 of R for train, validation and test, respectively. For the second model, the 2-2-2-1 structure of ANN with 0.0780, 0.0816 and 0.0908 of RMSE and 0.9598, 0.9799 and 0.9746 of R for train, validation and test, respectively had better results than other structures. The evaluation of these models with a second data set showed that the second model with shrinkage and power density as input with 0.067 of RMSE and 0.994 of R had better results than the first model with 0.173 of RMSE and 0.961 of R. These consequences expressed that the second model had higher reliability for prediction of MC based on shrinkage and power density during drying process.

In this study, a microwave dryer was developed with a real-time image recording system and a microwave power level program during the drying process. Two ANN models were used for modeling of drying kinetics of the potato slices. Also image processing algorithm was investigated by measuring the shrinkage of potato slice during the drying process. The outcomes revealed that shrinkage as input in the ANN had great effect on MC prediction during the drying process.

The tabletting process increases the density of the food. This process also facilitates transportation and reduces transmission and storage costs. In this research, soybean powder was used for tabletting experiments. The effect of the tabletting process on particle density, compressive strength and shrinkage of soybean tablet was studied. The experiments were carried out using soybean powder at feedstock moisture content of 30, 40 and 50% w.b., feedstock temperature 25, 45 and 60 °C, relaxation time of 5, 10 and 15 s, and die diameter of 6, 8 and 10 mm. The response surface method (RSM) with central composite design was also used to analyze the data and optimize the process. The result showed that the highest particle density was 3714.32 kg/mm3 under conditions of the feedstock moisture content of 50% w.b., feedstock temperature of 25 °C, relaxation time of 5 s, and the die diameter of 10 mm. During the tabletting prosses, the highest compressive strength (518.18 N) was obtained at the feedstock moisture content of 50% w.b., feedstock temperature of 65 °C, relaxation time of 5 s, and the die diameter of 6 mm. The highest shrinkage of soybean powder (57%) was obtained at the feedstock moisture content of 50% w.b., feedstock temperature of 65 °C, relaxation time of 15 s, and the die diameter of 6 mm. The best optimization results for tabletting conditions for soybean powder was under feedstock moisture content of 50% w.b., feedstock temperature of 42.03 °C, relaxation time of 5 s and die diameter of 10 mm. The predicted values of particle density, compressive strength and shrinkage at the optimized conditions were 4895.49 kg/mm3, 433.17 N and 9.03% with a desirability of 0.853, respectively.

Tomato is one of the most valuable sources of minerals and vitamins supply in the human diet. Low shelf life of tomato and its short shelf life with inadequate processing facilities lead to heavy financial losses. Therefore, preserving and processing of tomato are of the commercial importance. Drying is one of the preferred methods for tomato preservation. Dried tomato products including half tomatoes, tomato slices and tomato powder, have many consumptions, compared with other tomato products. Among dried tomato products, tomato powder has a particular market. Powder production is an alternative method to extend the shelf life of foods. Usually the fruit powder is very dry, humidity absorber and has too much volume. Therefore, during storage, transportation and administration, it requires special care and heavy packaging which increase the cost. To overcome these problems, compression of the fruit powder in tablet form could be a proper solution. Tablet making of fruit powder has gained much popularity due to its ease of use, storage, transportation and product formulation. After the tablet making process, the pills contain high moisture contentwhich makes them un-suitable for transportation and storage. So, in order to prevent the tablets corruption and maintain their quality, tablet drying is one of the important steps after the tablet making process. The drying process is an important operation that affects the quality and final price of the product. Different drying methods play an important role in protecting foodstuffs. However, the effect of different drying methods on the quality of some foodstuffs is not clear.

In this research, after the preparation of fresh tomatoes, the primary moisture content of tomatoes was determined using hot air oven method. Then, using blanching method, the tomatoes were peeled and samples were cut using a sharp razor in thicknesses of 3 mm. Tomato slices were dried using a semi-industrial dryer in a hot air at 50 °C at an air speed of 1 m/s. Dried tomato slices were powdered using a grinder. In order to homogenize the particle size, the tomato powder was sieved by a 50 mesh (Cavity size 0.5 mm) sample. Suitable moisture content to create sufficient adhesion between the particles of tomato powder was selected at %23 d.b. Water and fructose were used as a bonding agent. The process of producing tomato spherical tablets was performed by a hydraulic press. Drying tests of wet compressed tablets were performed immediately after the end of the tabletting process using a hot air drying machine with microwave pre-treatment. In this study, the effect of drying variables,through using of  microwave pre-treatment along with hot air, including air temperature in five levels (40, 50, 60, 70 and 80 °C), air velocity at five levels (0.5, 1, 1.5, 2, and 2.5 m/s) and the duration of microwave application at five levels (zero (without microwave), 4, 8, 12, and 16 s) on physical properties (shrinkage and unit density), mechanical (penetration resistance) and thermal (Effective moisture diffusivity and energy consuming drying) of compact pomegranate produced from tomato powder were studied. Statistical analysis of data and optimization of drying process were performed using response surface method and central composite design.

Results showed that effect of air temperature and duration of microwave pretreatment on all variables of compressed tomato tablets were significant in hot air dryers with microwave pre-treatment. Increasing temperature and time of microwave pre-treatment increased the effective moisture diffusivity and shrinkage of the final product. The temperature of the air inlet to the dryer had a negative effect on the resistance to penetration, the unit density and the specific energy consumption of the drying process. Drying under lower temperature conditions and less time for microwave pre-treatment resulted in an increase in the desirability of the drying process

In a vapor cloud explosion، flame propagation phenomenon and turbulence flow field occur simultaneously. At the same time، the existence of obstacles in the flame propagation direction، leads to wrinkling of the flame front. The mechanism of flame wrinkling phenomenon occurs due to the effect of the flame-vortex interactions. Large scale vortices deform the flame front and increase its surface area. Increasing flame surface area ends in an increase of burning velocity and intensification of pressure build up. The major challenge in modeling of large scale vapor cloud explosion is calculation of turbulent flame speed. In this paper a combined model of Weller''s wrinkling factor transport equation and SCOPE3 model was utilized to calculate this parameter. The SCOPE3 model considers high intensity turbulence. Therefore،the combined model is suitable for modeling of the vapor cloud explosion in presence of significant obstacles. Numerical results also confirm the ability of this model to accurately predict pressure history

In this study, the effect of effective variables of moisture content, particle size, type of adhesive and tablet shape on the qualitative properties (difference of color indices ΔL*, Δa* and Δb*), physical (unit density and shrinkage) and mechanical (diffusion force) indices of compressed tablets made from tomato powder were studied. Independent variables were including three levels of particle size of tomato powder (particles smaller than 0.3 mm, particles ranging from 0.3 to 0.75 mm and particles larger than 0.75 mm), three levels of moisture content (18, 36 and d.b. 54%), three forms of compressed pills (spherical, cylindrical and cubic), three types of adhesive (55% fructose syrup, water and sugar). For optimization, the surface response and Di-optimal method were used. The results showed that optimum spot was obtained for compressed pills consisting of tomato powder with a moisture content of %33.4 db, particle size of fructose 0.3 mm, and cylindrical tablet form, dried in oven at 60 ° C. Under these conditions, the desirability index was 0.826, and the optimal value of the independent variables ΔL*, Δa* and Δb* (the difference of color indices with fresh tomatoes), penetration force, unit density and shrinkage were 35.89, 15.6, 23.23, 267.2 N, 2299 kg/m3 and %12.2, respectively.

Garlic (Allium sativumL.) is one of the most important Allium spice. From an economic point of view, the dried garlic slices are valuable products. In this research, garlic slices as a thin layer were dried in a laboratory scale hot-air dryer, under air flow of 1.5 m/s, air temperatures of 50, 60 and 70˚C and slice thicknesses of 2, 3 and 4 mm. The mean values of shrinkage of garlic slices obtained 69.8%. In addition, the effects of the drying variables on the shrinkage of dried garlic were evaluated. The ANOVA results indicated that the air temperature and slice thickness had no significant effect on final shrinkage of dried garlic slices. In order to derive and select the appropriate shrinkage model, four mathematical models were fitted to the experimental data. According to the statistical criteria (R2, SSE & RMSE) the best model was found to describe the shrinkage behavior of garlic slice.

High temperatures during drying, with loss of water in the meantime, cause tension in the food, change the microstructure and reduce the volume (shrinkage). In this study, the effect of ultrasonic pretreatment at 10, 20 and 30 minutes and carboxymethyl cellulose with concentrations of 0.1, 0.2 and 0.3 percent on grapes shrinkage during drying and its modeling was examined. In this study, pretreated grapes were dried in a tunnel dryer and their volumetric changes were measured. Results showed that all the pretreatments have higher shrinkage compared with control samples, but this difference was not statistically significant. Also, by increasing ultrasound time, the shrinkage of the samples increased compared with control treatment. Control and pretreated samples with ultrasound for 30 minutes had the lowest and highest rate of shrinkage, respectively, in the various studied treatments. In the samples pretreated with both ultrasound and CMC, it was observed that by increasing the concentration of CMC, shrinkage of the samples decreases compared to its lower concentrations.

In this paper، the correlation between the surface rumpling and cracking phenomena with twinning mechanism during plastic deformation of Hadfield steel has been investigated. The effect of stacking fault energy and the amount of strain are evaluated. The experimental samples with specific amounts of carbon، manganese and aluminum resulting in different stacking fault energies، were produced using investment casting process. The tensile tests were conducted at ambient temperature. The microscopic and macroscopic investigations were done using optical and scanning electron microscopes. The observations have shown that surface crinkling of austenitic manganese steels is related to twining mechanism during plastic deformation. This plastic deformation mechanism causes rotation and inhomogeneous deformation of the grains and therefore، surface grains with free surfaces were becoming more crinkled and cracked. It was observed that crinkling and cracking phenomena takes place more and coarser with an increase in the strain.

The final quality of drying product should be considered as one of the most important indicators in the drying process.In this research, the effects of gamma irradiation doses (0, 1.2, 2.4 and 3.6 kGy), drying temperature (50, 60 and 70°C) and slice thickness of mushrooms (3 and 5 mm) on the surface shrinkage and rehydration ratiowere studied.Thin-layer dryer based on machine vision was used for the experiment.The results showed that the simple and intraction effects of the factorson the surface shrinkage and rehydration ratio weresignificant(P<0.01)in most cases.By increasing irradiation dose, shrinkage slightly increased, and rehydration ratio in dried samples were increased. Also,the maximum rehydration ratiowas 3.43g/gin dose of 3.6 kGy anddryingtemperature of 60°C in the thickness of 3 mm.Finally, shrinkage increased by increasing drying temperature and decreasing slicethickness of mushroom.So that the minimum and maximum values of surface shrinkagewere 0.461 and 0.667, respectively.

Drying of food products using microwave can be a good replacement to hot air dryers. In this study, Response Surface Methodology (RSM) was used for optimization of the conditions for microwave drying of persimmon slices. The effects of microwave power (300, 500 and 700 W) and slice thickness (3, 5 and 7mm) as independent variables on shrinkage percentage, processing time and total color change of persimmon as dependent variables (responses) were evaluated. All process variables were statistically significant as quadratic regression models for all responses. As microwave power increased, the shrinkage percentage and total color change of persimmon slice increased but processing time decreased. As the thickness of persimmon slice increased, the processing time and total color change of persimmon slice increased but shrinkage percentage decreased. The optimum conditions obtained for minimum shrinkage percentage, processing time and total color change were 3 mm as slice thickness and the microwave power of 312 W. In optimized condition, the shrinkage percentage, processing time and total color change of dried persimmon slices were 72.5 %, 5.97 min and 15.2, respectively.