Introduction: Fruits and their products in the dried form are good sources of vitamins, energy and minerals. However, during the process of drying or dehydration there are changes in quality parameters in dried products. Texture is one of the most important quality attributes of fruits during drying, reflecting their mechanical and microstructural properties. Apple is perishable fruit. Drying of apple is very important because of High losses are experienced during the seasonal glut. A novel process in food industry is the simultaneous infrared dry blanching and dehydration operation (SIRDBD) with intermittent heating method (radiation at constant temperature) exerted on fruits and vegetables that is known to enhance the quality of the final product. In the food industry, end-products must achieve a compromise between several properties, including sensory, sanitary and technological properties. Prediction of changes in texture during drying could be helpful in a better process control and improvement in overall acceptability of a dried snack food. The change of the elastic or viscoelastic texture of the fresh apples to rigid, fragile and brittle in the apple chips were evaluated by instrumental and sensory methods. Many attempts have been made to describe the viscoelastic behavior of dehydrated fruits and vegetables. Maxwell’ s or compression models are limited to homogeneous, isotropic materials. In contrast, texture profile analysis (TPA) is more suitable for heterogeneous biological materials and shows a good correlation with organoleptic evaluation. Typical TPA parameters are including hardness, adhesiveness, springiness, cohesiveness, gumminess, chewiness and resilience. In this research, for the first time, textural analysis of dried apple slices by infrared heating at different temperatures and different moisture levels was performed. Finally, the optimum texture and overall acceptance of the product are described according to the instrumental analysis. Materials and methods: Apples (Golden Delicious variety) were purchased from a local market and kept in 0° C± 1° C and relative humidity ranging from 90% to 95%. Before every thermal processing, the apple specimens were picked up from the cold storage and then they were put into use after reaching the ambient temperature. The samples were skinned manually and then cut into slices with different thicknesses of 5mm, 9mm and 13mm, all 20mm in diameter. The sliced apples were immediately subjected to simultaneous blanching and infrared drying. The texture of dehydrated apple slices using infrared radiation at three surface temperatures of 70, 75 and 80 ° C were studied. The product in three thicknesses was dried to achieve a moisture level of 15, 20 and 25% wet weight basis. Then, texture profile analysis (TPA) was carried out to 50% compression strain using texture analyzer. The sensory evaluation of dried slices was also considered for desire texture (Good mouth feels texture, lack of hard tissue, no shrinkage) and overall acceptance (The final acceptability of the product in terms of total sensory properties including color, texture, flavor and aroma) by 10 professional panelists. For statistical analysis, a completely randomized design (CRD) was used in a factorial form (3 3 ) and Duncan test with 95% confidence level. Result & Discussion: The results showed that drying to studied moisture levels reduced the hardness and adhesiveness and increased springiness, cohesiveness, gumminess, chewiness and resilience in comparison with raw apple tissue. Hardness of samples dried at higher temperature was higher due to rapid removal of moisture which might have caused collapse of capillary voids inside the product. Due to shrinkage samples became denser and thus a larger fracture force was to be expected. As water content increases (i. e., higher RH) water plasticizes the cell walls and the material and product becomes softer and more pliable, thus hardness decreases. The increase of hardness could be because the rapid mass transfer that damaged the membrane and cell structure of the fruits during drying. Another important factor responsible for the increase of hardness of finish-dried samples is the low final moisture content when compared with other samples. High temperature drying method enables samples to reach low moisture content at relatively short duration and therefore the product with harder texture was obtained. The maximum value of adhesiveness was observed for fresh apples, which could be attributed to the high moisture and sugar content. Adhesiveness decreased with moisture loss, indicating the availability of free water on the sample surface. A significant decrease in springiness following hightemperature drying could be attributed to the glass transition phenomenon and changes from elastic to plastic behavior. In the period of softening, cohesiveness increased with moisture loss. Hardening caused a decrease in cohesiveness depending on the drying temperature. Gumminess is the energy required to disintegrate a semisolid food to a state of readiness for swallowing. High values of gumminess revealed “ firm” and “ crisp” with a cell rupture mode of tissue failure and lowest values of gumminess could be classified as “ soft” . At the end of drying and with apple hardening, chewiness increased to values equal or above initial chewiness, indicating that a larger amount of energy is needed to masticate dried apples. Resilience had increasing with moisture loss. By increasing the thickness of the slices, the cohesiveness and springiness decreased and hence chewiness significantly decreased. The overall acceptance and desire texture in dried samples was observed at lower water evaporation rate conditions (lower temperatures, lower thickness and higher moisture content). In these conditions, the hardness of apple slices tissue was equal to 695. 177 ± 7. 685 grams. During drying of the apple, textural behavior was varied from the viscoelastic (higher initial hardness, with cohesiveness, springiness and lower resilience) to elastic and then to plastic or glassy.

Introduction: Dehydration of fruits and vegetables is a widely used unit operation (Funebo et al., 2000). Intermittent infrared radiation, in which the product surface maintained at constant temperature, is a novel drying method to produce high quality dehydrated fruits and vegetables (Zhu and Pan, 2009; Zhu et al., 2010). During the drying, one of the most important physical changes in the quality of food is the decrease in external volume. This change in volume is called shrinkage and is an unavoidable phenomenon during the dehydration process. Shrinkage is usually expressed by the ratio between the volume of the sample after and before drying (Yan et al., 2008). Shrinkage also affects the porosity of dried materials and it is the parameter determining about the mass transfer properties, mechanical properties, and the texture of food product (Witrowa-Rajchert and Rzą ca, 2009). The three qualitative parameters such as the degree of shrinkage, density and firmness of the product are related to each other (Funebo et al., 2000). Maximal shrinkage and structural collapse were shown to decrease until kept quality characteristics (Barzaghi et al., 2008). The factors affecting shrinkage include volume of water extracted from the product, mechanical mobility of the solid matrix, drying rate, and process conditions such as temperature, air flow rate, and relative air humidity (Moreira et al., 2000). The mechanical mobility of texture in plant based foods during processing is affected by dry matter, starch and cell wall constituents, and it can be said that due to the high thickness of the cell wall, cell separation due to water evaporation pressure is more than cell rupture (Sabbaghi et al., 2017). The important consequences of shrinkage occurring during drying result in a loss of rehydration ability. Dehydrated products are usually rehydrated prior to their use (Krokida and Marinos-Kouris, 2003). The rehydration behavior is studied as an indicator of texture damage (Giraldo et al., 2006). Rehydration is a complex process that is intended to restore the properties of the fresh product by contacting dehydrated products with a liquid phase. This process to be composed of three simultaneous steps: (1) absorption of water into the dry material, (2) swelling of the rehydrated product, and (3) loss or diffusion of soluble components. Rehydration ability or capacity measures the ability of a dehydrated product to rehydrate (Maldonado et al., 2010). Mathematical models of rehydration will be useful in designing and optimizing this operation that have been applied as exponential models or capillary absorption theory or Fick’ s diffusion laws (Lee et al., 2006). In this research, the effect of this heating method on the physical-qualitative characteristics of dried apple slices, including volume, density, shrinkage and behavior of rehydration were studied. Material and methods: Apples (Golden Delicious variety) were purchased from a local market and according to Acevedo et al., 2008 kept in 0° C± 1° C and relative humidity ranging from 90% to 95%. The samples were skinned manually and then cut into slices with different thicknesses of 5mm, 9mm and 13mm and all with 20mm in diameter. The average moisture content of apple was measured using oven (Binder FD53) at 103 ° C for 24 hours and it was equal to 84. 11% based on wet weight (AOAC, 2000). Operation of infrared radiation with intermittent heating method was performed at three constant temperatures of 70, 75 and 80 ° C using the infrared dryer similar to Liu et al., 2014. Shrinkage coefficient of product was estimated with both theoretical (β theo) and practical (β ) methods according to Talla et al., 2004. Also, the mathematical models as Peleg (Reyes et al., 2011) and Exponential (Krokida et al., 2003) equation were compared to describe the rehydration process in dried product using adjusted R-squared (Adj. R 2 ) and root mean squared error (RMSE). Statistical analysis of the effect of thickness and temperature on the shrinkage coefficients (β theo, β ) was performed in SPSS software in version of 19. To achieve this aim, a completely randomized design (CRD) with factorial arrangement with two factors as thickness (at three levels) and temperature (at three levels) was used. Also, two methods of computing the shrinkage coefficients (theoretical and practical) were compared together with one-way F test. Mean comparison was performed by Duncan test with 95% confidence level (P<0. 05). All experiments were performed in three replications. Results and discussion: The results showed that increasing of the temperature caused greater volume and density changes during rapid dehydration of the product. The density changes were more intense for the thin product (reducing the final density to about 0. 6 g/cm 3 ). Also for thicker products, the density changes were slower during the process (reducing the final density to about 0. 7 g/cm 3 ). During process, the variation of product shrinkage indicated an exponential rising trend which was influenced by the amount of evaporated water. Shrinkage coefficient is significantly increased at higher processing temperature and thickness of product (β equal to 0. 164), representing that the product is heavily affected by the structural collapse phenomenon. The observations were similar to those reported by many researchers (Mayor and Sereno, 2004; Nowak and Lewicki, 2004; Katekawa and Silva, 2006). The temperature of 80 ° C showed significantly higher theoretical and practical shrinkage coefficient than the other two tested temperatures (70, 75 ° C). The difference between the two methods of calculation in shrinkage coefficient (theoretical and practical) was also significant and the difference increased with the increase of temperature (more than 6%). Jannot et al., 2002 reported that the error in the practical method can be due to the noisy data (deviation from the actual value). Limitation of rehydration capacity (RC) in slices with high shrinkage stress confirms the damage of the texture of the product (reduction in predicted equilibrium moisture content: Xe from 6. 523 to 4. 148 kg/kg, db). Rehydration process in different product thicknesses is described better using Peleg model (higher Adj. R 2 and lower RMSE) compared with the exponential one. The observations were similar to those reported by many researchers (Krokida and Marinos-Kouris, 2003; Nathakaranakule et al., 2010). Conclusion: The physical properties including shrinkage and density in the dried product are affected by process and product conditions. The low occurred shrinkage that reflects the preservation of the internal structure of the product and will be effective in rehydration behavior. In fact, reabsorption cannot be simply defined as the returned process of dehydration. Because of moisture reabsorption is completely affected by the texture, structure and properties of the dried product. Therefore, mild thermal conditions prevent the structural breakdown of apple slices and, at low thicknesses, due to the reduced volume of water evaporated from the slices, the shrinkage coefficient is reduced, thus preserving the internal physical structure of the infrared dried product.

In order to investigate the effect of glycine-betaine (GB) and intermittent warming (IW). On shelf life and quality of sweet pepper fruits an experiment was conducted as a factorial based on complete randomized design in University of Zanjan in 2016. Treatments were consisted of intermittent warming at three levels (control, 20 and 30 º C) and glycine-betaine at three levels (0, 5 and 10 mM). The fruits were stored at 4 ° C and 85± 5% RH for 30 days. The results showed that the amount of vitamin C, chlorophyll, carotenoids content and peroxidase activity in the fruits were decreased and fruit weight loss percentages, extract pH and electrolyte leakage were increased during storage at low temperature (4 ° C) by gradually increasing of storage time. Intermittent warming and glycine betaine had positive effects on studied traits such as soluble solids, extract pH, vitamin C, chlorophyll, carotenoids content and peroxidase activity and improved the quality of pepper fruit during storage at low temperatures. These treatments prevented weight loss and electrolyte leakage during the storage. The intermittent warming between temperatures of 20 ° C and 5 mM of GB were found to be more beneficial in improving the qualitative characteristics of pepper fruits. Therefore, the use of glycine betaine and intermittent warming can increase quality of sweet pepper, and by preventing the increase of contamination, can be improved the shelf life of sweet pepper.

Infrared radiation by intermittent heating is a novel method in which the surface temperature of the product is maintained at a constant value. This method is widely used in simultaneous blanching and drying process. The main advantages of intermittent IR-radiation are energy saving and preventing undesirable quality changes in the final product. The calculations of mass transfer in this process can be used to estimate the temperature and time conditions in the process. For this purpose, drying behavior of apples slices (Golden Delicious variety) was investigated with slab shape in three different sizes: thickness of 5, 9 and 13 mm and length and width was 20 mm. Heating operation performed by infrared dryer that was equipped with controller of product surface temperatures at 70, 75 and 80oC. Kinetic models such as Newton, Page, Modified Page, Henderson-Pabis and parabolic were fitted on experimental data of dimensionless moisture ratio using MATLAB software. The adjusted correlation coefficient (Adj.R2) and root mean square error (RMSE) were used to compare the models. The evaluation of effective moisture diffusivity (Deff) performed during drying of slices and its dependency with temperature investigated using Arrhenius equation. The results showed that models of page and parabolic presented a good fit on experimental data, respectively (higher Adj.R2 and lower RMSE). The effective diffusion coefficient significantly elevated with an increase in surface temperature and thickness. This parameter showed higher energy activation for lower thicknesses that indicated a greater irradiation temperature dependence of effective diffusion coefficient through the decreasing of thickness.

In this study, fuzzy temperature controller was designed using stepwise heating during the infrared irradiation of apple with intermittent heating method. For this purpose, the dry blanching process and dehydration of apple slices were examined at three temperatures of 70, 75 and 80° C based on inactivity of polyphenol oxidase enzyme (PPO) as blanching speed index and vitamin C preservation as maintaining quality index. The samples were removed from the infrared dryer in 2-minute intervals to separate the time required for the dry blanching process and dehydration of apple slices. For all temperatures, the heating process was continued until no sign of color change stemming from catechol reagent (adequacy of blanching). Finally, the fuzzy controller of the temperature with the feedback loop was designed, simulated, and implemented by comparing two first and second order transfer functions in MATLAB software. Simulation efficiency was examined using the indices of integral squared error (ISE), integral absolute error (IAE), integral time-weighted absolute error (ITAE) and steady state error (ess). These parameters must be close to zero. The results revealed that the temperature of 80° C and time of 15 minutes were appropriate for blanching operation and the temperature of 70° C was appropriate for dehydration. The simulation results confirmed that the higher order of the transfer function led to a faster response, but an increase in oscillations and reduction in the stability were not appropriate. For the first-order transfer function, the values of efficiency indices, including (ISE), (IAE) and (ITAE) were calculated to be 0. 760, 0. 821 and 0. 589, respectively, of the second-order transfer function. The simulation indicated the reliability of the fuzzy control model and showed an acceptable computational efficiency, since the fuzzy rule test during simulation showed high sensitivity to maintain steady state error (ess) close to zero.

A B S T R A C T Temperature is one of the climate elements that has fluctuated a lot over time. When these fluctuations increase and decrease more than normal and are placed in the upper and lower regions of the statistical distribution, if continued, it can lead to the creation of heating and cooling waves. The purpose of this study is to analyze the temporal and spatial changes in heating and cooling waves in Iran during a period of 50 years. For this purpose, the temperature of 663 synoptic stations from 1962 to 2004 was obtained from the Esfazari database. Then, in order to complete this database, the daily temperature from 2004 to 2011 was obtained from the Meteorological Organization of the country and added to the aforementioned database. In order to perform calculations and draw maps, Matlab, grads and Surfer software have been used. The results of this study showed that the index of cooling waves and heating waves, while having a direct effect on each other, had an increasing trend in most of the area of Iran. The statistical distribution of the index of cooling waves is more heterogeneous than that of the index of heating waves. So that the spatial variation coefficient for cold waves is 84.22%. Also, the index of cooling waves has more spatial variability. The highest common diffraction of the index of heating and cooling waves has been seen in the northwest, east and along the Zagros mountains. Analysis of the indexes trends show that heat waves have intensified in 65.8% of Iran and the intensity of cold waves has decreased in 48.5% of Iran Extended Abstract Introduction Temperature is one of the major climatic variables, which it has a direct impact on different aspects of human life. It plays an essential role in the growth of crops and is considered a key driver of the biological system(Reicosky et al, 1988). It is associated with several types of extremes, for example, heat and cold waves which caused human societies maximum damage. Past occurrences of heat waves hitherto had significant impacts on several aspects of society. Have increased Mortality and morbidity. Ecosystems can be affected, as well as increased pressure on infrastructures that support society, such as water, transportation, and energy(Dewce, 2016). The long-term change of extreme temperatures has a key role in climatic change. The form of statistical distribution and the variability of mean values and also extreme event indicate a change in the region. It can be a small relative change in the mean as a result of a large change in the probability of extreme occurrence. Also, the variation in temperature data variance is significantly more important than the mean, for assessing the extreme occurrence of climate(Toreti and Desiato, 2008). The average surface temperature has increased the world between 0.56 and 0.92 ° C over the past 100 years(IPCC, 2007). Meanwhile, it was in the Middle East, the average daily temperature increased by 0.4-0.5 ° C in decades(Kostopoulou et al, 2014; Tanarhte et al, 2012). Considering that not many studies have been done in the field of spatio-temporal Variations of the heating and cooling waves thresholds in Iran, in this study, the spatio-temporal Variations of the heating and cooling waves thresholds in Iran during 50 years were examined and analyzed.   Methodology The daily temperature from the beginning of the year 21/03/1967 to 19/05/2005 was obtained from the Esfazari database prepared by Dr. Masoudian at the University of Isfahan. In order to increase the time resolution of the mentioned database, the daily temperature of observations from 05/21/2005 to 05/12/2012 has been added to the mentioned database using the same method, and the exact spatial resolution (15 x 15 km) is used as a database. Threshold indices of heating waves are the average numbers between the 95th and 99th percentiles, that is, the extreme hot threshold to the limit of excessively extreme hot. For extreme cool, from the 5th percentile down to zero is used. Of course, a condition was added to these thresholds, which is that these thresholds must be repeated two days in a row. These thresholds were extracted for each day in the 50 years of the study period and used as the original database. In order to analyze the relationship between cooling and heating waves, Pearson's correlation coefficient was used and regression was used to analyze the trend.   Results and discussion The average of cold waves was 5.26 ° C and for the heat waves is 30.20° C. Generally, if the temperature is upper or lower than this threshold, it is considered as hot or cold temperatures. A comparison of the median, mode, and average of cold waves with heat waves shows that the distribution is more heterogeneous for cold waves and its CV is 84.22%. In southern Iran, the average threshold heat waves are higher. This situation can be caused by the effects of subtropical high-pressure radiation, low latitude, and proximity to the sea. Though the threshold is higher in these areas, fewer fluctuations and changes are seen in the area. Heights moderate the temperature so they pose a minimum threshold for heat waves i.e. an iso-threshold of 25 ° C is consistent along the Zagros mountain chains, but in the west and east of Zagros Mountains, the threshold of heat waves is increased. Heat waves have increased in most areas of the country. So nearly 85 percent of the Iran has been an increasing trend, of which 65.8 percent is statistically significant at the 95% confidence level. Still, more areas of the country (60 percent) have a trend between 0.00828 and 0.00161. As can be seen, only 15% of the land area (including the southwest and northwest of the Country) had decreased heat waves. Cold waves, in most parts of the country, have a Positive Trend. However, about 25 percent of the study area's cold waves have a negative trend. they are located in areas higher than Latitude 30°. The largest decline of the wave's trend along the country is highlands. Nowadays, most of the country, has a trend between 0.01494 and 0.00828 ° C, respectively. Conclusion Common changes and effects of heat and cold waves had a direct relationship in many parts of the country. It is remarkable common variance in the East reached 55 percent, according to statistical significance. In some areas of the northwest and southwest, which have been impressive heights, the common variance is 40 percent. This common variance in mountains area has been high values. Investigation of heat waves trend shows that 65.8% of Iran significant positive trend and 7.1% significant negative trend. Also, the cold waves trend has indicated a 48.5% significant positive trend and a 10.8% significant negative trend. Climate change and global warming have changed the frequency and severity of temperature extremes. The present study, by examining the number of warm waves, concluded that the warm waves have increased in magnitude in 65.8% of the Iran zone. Also, the study of the cold waves trend showed that 48.5 percent of Iran had a positive trend, which means that the amount of temperature in the cold waves increased In other words, the severity of the cold has been reduced And only 10.8 percent of Iran had a negative cold wave trend And it shows the intensity of these waves is reduced.   Funding There is no funding support.   Authors’ Contribution The authors contributed equally to the conceptualization and writing of the article. All of the authors approthe contenttent of the manuscript and agreed on all aspects of the work declaration of competing interest none.   Conflict of Interest The authors declared no conflict of interest.   Acknowledgments  We are grateful to all the scientific consultants of this paper.

Magnetically confined plasma can be heated with high power microwave sources. In spherical torus the electron plasma frequency exeeds the electron cyclotron frequency (EC) and, as a consequence, electromagnetic waves at fundamental and low harmonic EC cannot propagate within the plasma. In contrast, electron Bernstein waves (EBWs) readily propagate in spherical torus plasma and are absorbed strongly at the electron cyclotron resonances. In order to propagate EBWs beyond the upper hybrid resonance (UHR), that surrounds the plasma, the EBWs must convert via one of two processes to either ordinary (O-mode) or extraordinary (X-mode) electromagnetic waves. O-mode and X-mode electromagnetic waves lunched at the plasma edge can convert to the electron Bernstein waves (EBWs) which can propagate without and cut-off into the core of the plasma and damp on electrons. Since the electron Bernstein wave (EBW) has no cut-off limits, it is well suited to heat over-dense plasma by resonant absorption. An important problem is to calculate mode conversion coefficient that is very sensitive to density. Mode conversion coefficient depends on Budden parameter (h) and density scale length (Ln) in upper hybrid resonance (UHR). In Mega Ampere Spherical Tokamak (MAST), the optimized conversion efficiency approached 72.5% when Ln was 4.94 cm and the magnetic field was 0.475 Tesla in the core of the plasma.