داریوش زارع

Drying shrimp is one of the storage methods that, while increasing the shelf life, leads to the production of a versatile product with various uses, from consumption as snacks to use as one of the main components of foods. Drying is preferred over other preservation methods because it offers numerous advantages, including extended shelf life, enhanced microbial stability, convenient consumption, reduced transportation costs, increased value, and product diversity.To accurately model these processes and thus obtain information on factors such as shelf life and energy consumption, it is necessary to determine the product’s initial and final temperatures, its geometry and dimensions, and its thermo-physical characteristics. Simulation of different drying processes requires accurate estimation of the effective moisture diffusion coefficient, which is highly dependent on temperature and humidity. Its dependence can be shown by an equation with an Arrhenius structure as an empirical function of humidity and temperature, or by considering the activation energy.It is necessary to have sufficient knowledge about heat and mass transfer characteristics, such as diffusion or penetration coefficient and the heat transfer coefficient to estimate the final temperature and drying time. This study investigated the drying process of peeled farmed shrimp (Litopenaeus vannamei) using a convective hot air dryer. Various parameters such as shrinkage and the effective moisture diffusion coefficient were examined.

A drying device was built to conduct experimental studies on drying shrimp samples. The experiments were conducted on sliced shrimp meat samples at temperatures of 40, 50, and 60 degrees Celsius, with a constant air velocity of 1.5 m/s. The experimental drying models were based on diffusion theory. In these models, it is assumed that the resistance to moisture diffusion occurs from the outer layer of the food. In most cases, Fick's second law was used to describe the phenomenon of moisture penetration.The study used the standard method of immersion in toluene to measure volume changes in the samples. During the drying process, the volume of the samples was measured at 45-minute intervals, and their volume changes were calculated. To measure the moisture content of the samples, each test started by recording the initial weight of the samples using a digital scale with an accuracy of ±0.001 g. During the drying process, the samples were weighed each time their volume was measured.Shrinkage during the drying process is commonly modeled by finding a relationship between shrinkage and moisture, using linear and non-linear models. In most cases, effective permeability is defined as a function of humidity and temperature. For this purpose, curve-fitting methods were employed to analyze the data collected from experimental tests. The appropriate function was extracted by incorporating the Arrhenius equation, which is applicable to most food items.

Based on the results of statistical indices, the linear model was the best model for depicting the relationship between shrinkage changes versus moisture ratio changes among the various experimental models evaluated for shrinkage and drying kinetics. Similarly, the Weibull distribution demonstrated superior performance in expressing variations in moisture ratio over time. A moisture dependent experimental model was used to express the variations in the apparent density of shrimp, resulting in a computed range of 1017-1117 kg m-3. Furthermore, an Arrhenius equation was derived to express the effect of moisture content and temperature on the effective diffusion coefficient of shrimp. According to the results, the effective diffusion coefficient of shrimp exhibited variations ranging from 0.08 ×10-9 m2 s-1 to 7.39×10-9 m2 s-1. When deriving the effective diffusion coefficient, the impact of the number of terms in Fick's second law on the variation of the moisture ratio was studied. The findings revealed that increasing the number of terms beyond 100 did not significantly affect the model’s outputs.

The linear model had the highest coefficient of determination (R2) among the evaluated shrinkage models, as well as the lowest root mean square error and sum of square error (SSE). This makes it the most optimal model for interpreting shrinkage at the tested temperature levels. The Weibull distribution experimental model proved to be the most suitable for expressing changes in the moisture ratio of shrimp meat slices over time within the evaluated temperature range. The Arrhenius model accurately predicts changes in the effective diffusion coefficient of shrimp slices with respect to temperature and moisture content within the tested temperature range.

Parboiling is one of the postharvest hydrothermal treatments applied on rough rice before drying and milling processes. This process has an important role in retaining the quality of rice kernels during storage, milling, and cooking. In this study, two rough rice cultivars, Tarom and Fuji Minory, were subjected to conventional and multi-step soaking for 90 minutes in water at temperatures of 50, 60 and 70 °C as a part of the parboiling process. Multi-step soaking was conducted in two and three steps followed by 15 minutes steaming at atmospheric pressure. Drying was performed by a fixed bed hot air dryer at 35 °C. The results indicated that in the conventional soaking, soaking temperature and steaming time affected the percentage of broken rice, bending strength and head rice yield (HRY) for both cultivars in a significant manner (P<0.05). The effect of soaking steps and steaming duration on the percentage of broken rice, bending strength, and HRY at temperature 70 °C were significant (P<0.05) for both rice cultivars. In overall, the multi-step soaking showed a significant positive impact on measured traits as compared to conventional soaking.

Separation and weighing of broken of rice kernels within a batch is a common way for measuring the amount of brokens. Separation is carried out by sieve or hand that is time-consuming method and required periodical sampling. In the present study, some image texture features of a rice batch for determining the percentage of brokens were applied. In order to this, twenty-one samples of 100 g were prepared with different breakage percentages from mixture of broken and whole rice kernels (containing zero to 100 percent broken). Ten images were then taken from each sample batch. After pre-processing of the images such as noise removing and creating binary images, the texture features of the images were extracted using MATLAB software. Twenty-three texture features were extracted using a grayscale co-occurrence matrix method. The principal components analysis (PCA) method was employed to reduce number of the features. By which, 23 calculated and measured texture features was reduced to three principal components (latent variables). Then, the relationship between percentage of broken rice in the sample and the principle components of 23 extracted texture features from the images by artificial neural network method was pinpointed. Four different topology of neural networks with different neurons in two hidden layers were employed. The results of neural networks outputs revealed that 3-6-8-1 topology could determine the percentage of broken in a batch of rice kernels with 0.958 coefficient of determination (R2) and total estimation error of 1.5 percent. Moreover, it was found that 10 texture features were related to first principal component, four features related to second component, four related to third component, and five fractures were simultaneously related first and second principal components. Eight features with correlation more than 0.9 with the first and third principal component had the most impact on estimation of percentage of broken. This method of measurement is fast, affordable and has proper precision with respect to the common (hand) method for online applications.

In this study pressure drop of bin containing corn as granular porous material with two common inlet duct arrangements (H, F) for a laboratory silage was studied by using experimental method. Higher pressure was obtained for the F arrangement compare to the H arrangement. The Ergun equation was fitted on the pressure drop of empirical data and the correction coefficients of modified Ergun equation for both H and F arrangements were determined. The coefficient of determination, mean root square error and mean relative error were used as indices to investigate the goodness of fitness between the empirical data and Ergun equation, and the equation had good fitness on the empirical data. The numerical simulation was carried out by finite element simulation of COMSOL Multiphysics v5.3 software using the modified Ergun equation. Moreover, distribution of velocity and flow lines within the bin was also presented.

In this paper, the simulation of green peas drying process in a hot air-Infrared dryer was carried out using two- dimensional finite element method. For this purpose, the mass transfer governing equation with initial and boundary conditions were derived. The system of first order differential equations were developed by using finite element method with Galerkin approach. To simulate drying process and solve the differential equations, a Matlab program code was developed. The drying simulation process was performed with combinations of four infrared power densities (0, 2000, 4000, and 6000 W.m-2), three levels of drying air temperatures (30, 40, and 50 ℃) and three levels of drying air flow rate (0.5, 1.0, and 1.5 m.s-1). Finally, in order to validate the developed model, the simulation results were compared with experimental data resulted by a hot air-Infrared dryer. The minimum, maximum and average relative errors between experimental and predicted data by finite element method simulation were 2.21%, 3.77%, and 2.50%, respectively. The model has reasonable accuracy and high efficiency for predicting the moisture content variation of green peas during drying process and can provide more information on the moisture transfer without running any experiments, so that it can be useful for designing dryers.

Rough rice is one of the most important agricultural products and it plays an important role in ensuring food security. The objective of this study was to investigate the effect of high power ultrasound in tempering duration on the drying kinetics of rough rice in a combined far-infrared radiation (FIR) dryer. Tests were conducted in a factorial design at four levels of ultrasound power density (Zero, 0.5, 0.75 and 1 kW/kg), four levels of frequency (20, 25, 28, and 30kHz) and three levels of drying air temperature (30, 40, and 50oC). Results showed that mechanical characteristics of rough rice were affected significantly at all ultrasound power and frequency levels at different inlet air temperatures at tempering duration and led to reduction of both drying time and specific energy consumption. So that at power of 0.5 kW / kg, low ultrasonic frequencies of 20 and 25 kHz and input temperature of 30 ° C while reducing the percentage of cracks in rough rice kernels, they also increase the energy required for healthy seed breakage on average.

The effect of using microwaves instead of steaming in parboiling step on mechnial properties of two paddy variety such as breakage strength and healthy rice yield were studied. Paddy samples were soaked in hot water at 50, 60 and 70°C for two hours and then exposed to microwave radiation for 15, 30, 45, 60, 75 and 90 seconds at the output power of 800 Watts. Sample were divided into two categories, one steamed at atmospheric pressure for 15 minutes and another was not. Finally, all the samples were dried at 35 °C. An increasing trend for breakage strength and healthy rice yield (for both paddy varieties) was observed when microwave exposure duration was increased. This increase was significantly different in treatments with microwave duration greater than 30 s as compared to control. The highest kernel bending strength and healthy rice yield in 90 s microwave treatment and soaking temperature of 70 ° C for Fajr and Lanjan varieties  were 24.7 MPa and 70.7%, and 20.8 MPa and 75.5%, respectively. There was no significant difference between breakage strength and healthy rice yield of steamed samples for 15 minutes and non-steamed microwave treatment for both varieties. According to these results, the impact of microwave on parboiling process was acceptable and can be replaced by steaming.

During filling a silo, granular material containing a range of particle sizes, the fine material accumulates under the filling point. The inclined surface of stationary bed particle which is formed in silos during filling process acts similar to a sieve through which the smaller particle fall. This effect is called sifting. As a result of the mentioned effect, much finer particles form a vertical cylindrical zone of high concentration at the silo center. For optimal design in industrial process such as aeration of stored products in silos, filling silos, and wherever granular materials are handled, it is necessary to survey the distribution of the fine materials depending on product and process properties. The objectives of present study were: (a) To study fine change as affected by substantial parameters, (b) To model fine changes at different conditions in silos. In the present study, an experimental setup consist of a main container, elevator, trapezoidal container and experimental silo was designed and built. Fine content was defined by BCFM (broken corn and foreign material). By applying a new approach, sampling was performed in a radial and vertical direction. The position of each sampling point was determined with a scaled distance from center (R) and from bottom (Z). Local BCFM (BCL) was defined as the value of BCFM in each sampling point. Influential parameters namely, initial BCFM (BCI), volume flow rate (Q) and fill pipe diameter (DF) were considered as treatments. Non-linear regression technique was applied on the experimental data to predict the distribution pattern of fines into the pilot-scale silo. The most appropriate model in a try and error procedure was selected based on highest value of R2 and least value of χ2, RMSE and MRDM. According to the results of ANOVA, it was found that the effects of all parameters were significant at 5% probability. BCL decreased nonlinearly with a concave down decreasing trend along radial direction due to sifting effect. As a result, most amount of fines remained in the sections closer to the center of the silo. Fine distribution became more uniform with decreasing Z and increasing BCI and DF. Also, the distribution of fine became more uniform with increasing Q. BCL was a nonlinear function of R and a linear function of Z, BCI, Q and DF. Although including more and complex terms increased the model complexity but in the present study considering BCL as an exponential function of R and as an implicit function of Z and R (ZR) improved the quality of the model significantly. The values of 0.94, 1.14, 1.06, 11.39 for R2, χ2, RMSE and MRDM, respectively, gave the best model. The results showed, considerable accumulation of fines occurred at the center of the silo which increased with increase of level of Z. Also, low concentration of fine occurred at the periphery of the silo especially at higher levels of Z. It means that maximum non-uniformity of fine distribution occurred at higher levels of Z. The present study investigated distribution of fines during filling affected by main parameters namely, initial BCFM, volume flow rate and fill pipe diameter in a pilot scale silo. A new procedure was developed for measuring the fine material along radial and vertical directions. Distribution of fine was modeled using a developed equation considering the effects of main parameters. The results showed that distribution of fine becomes more uniform with decreasing height and increasing initial BCFM, volume flow rate and fill pipe diameter.

A practical model including a parameter as a function of drying condition were introduced to predict the effect of far-infrared radiation (FIR) in a combined rough rice drying process. Tests were conducted in three replication for four levels of FIR (0, 0.1, 0.2 and 0.3 Wcm-2) and three levels of inlet air temperature (30, 40 and 500C). The results obtained from the simulation of the proposed model demonstrated that the models were capable satisfactorily express the characteristics of drying rough rice in combined dryer. Also due to the effects of combination of hot air and FIR drying technique on drying rates, cracking enhancement ratio (CER), required breaking energy for grain, specific energy consumption (SEC) and optimal method was presented. Combination of hot air at temperature of 40 0C and FIR at intensity of 1000 W.m-2 is the best way to have lowest SEC and highest grain quality point of view.

Several studies have been conducted on equipping conventional fluidized bed with some technologies to increase drying efficiency and its performance. The objective of the study was to investigate the influence of high power ultrasound on fluidized bed drying of corn in terms of drying kinetics and quality characteristics of corn in three levels of ultrasound power density (11.1, 14.6 and 18.7 kW m-3), three levels of drying air temperature (30, 40, and 50 ºC) and four levels of frequency (20, 25, 28, and 30 kHz) in which the moisture content reduced from 32±0.5 (%d.b.) to 17±0.5 (%d.b.). Results revealed that the frequency of 25 kHz was the most efficient in terms of drying time. The frequency of 25 kHz and power density 14.6 kw m-3 was the most efficient frequency and caused reduction of the drying time by 43% in comparison with no ultrasound condition (control). The sponge effect caused by ultrasound application led to reduction of failure strength and toughness of the dried samples. According to the results, toughness compared to the failure strength was an appropriate index of the grain hardness.

Sugar beet (Beta vulgaris L.) as the second most important world’s sugar source after sugarcane is one of the major industrial crops. The presence of weeds in sugar beet fields, especially at early growth stages, results in a substantial decrease in the crop yield. It is very important to efficiently eliminate weeds at early growing stages. The first step of precision weed control is accurate detection of weeds location in the field. This operation can be performed by machine vision techniques.
Hough transform is one of the shape feature extraction methods for object tracking in image processing which is basically used to identify lines or other geometrical shapes in an image. Generalized Hough transform (GHT) is a modified version of the Hough transform used not only for geometrical forms, but also for detecting any arbitrary shape. This method is based on a pattern matching principle that uses a set of vectors of feature points (usually object edge points) to a reference point to construct a pattern. By comparing this pattern with a set pattern, the desired shape is detected. The aim of this study was to identify the sugar beet plant from some common weeds in a field using the GHT.
Images required for this study were taken at the four-leaf stage of sugar beet as the beginning of the critical period of weed control. A shelter was used to avoid direct sunlight and prevent leaf shadows on each other. The obtained images were then introduced to the Image Processing Toolbox of MATLAB programming software for further processing.
Green and Red color components were extracted from primary RGB images. In the first step, binary images were obtained by applying the optimal threshold on the G-R images.
A comprehensive study of several sugar beet images revealed that there is a unique feature in sugar beet leaves which makes them differentiable from the weeds. The feature observed in all sugar beet plants at the four-leaf stage was a stretched S-shaped curve at the junction of the leaf and petiole. This unique shape characteristic was used as the pattern for sugar beet detection using GHT. To implement the Hough transform in the images, a 50-member group of samples was prepared from S-shaped curve to build appropriate patterns. Desired features for the Hough transformation were extracted from the patterns. In the next step, the attempts were made to find the images for the shapes similar to each of the patterns.
Plants were thoroughly separated from soil and residues. The accuracy of segmentation algorithm was achieved by almost 100%.
The accuracy of the generalized Hough algorithm was evaluated in two stages. In the first stage, the algorithm accuracy was assessed in detecting patterns in the images. Results showed that the accuracy of the algorithm was 96.21%. In the second stage, the algorithm was evaluated for some other test images, whereas the algorithm achieved an overall accuracy of 91.65%. In some cases, the presence of a large overlap between objects in the image reduced the detection accuracy. This was because of two main reasons; 1) high interference and ambiguity in the object edges, so that Hough transform was not able to detect the predefined patterns in the objects and, 2) weeds highly overlapped with sugar beet plants and thereby they were wrongly detected as sugar beet. However, since there is no or little interference between plants at the four-leaf stage, this interference can be eliminated by morphological operations. Due to this fact, it can be said that the results of GHT algorithm are acceptable for the detection of sugar beet in the plants close to four-leaf stage.
A special feature in the shape of sugar beet leaves was used as a criterion to distinguish between sugar beet and weeds. The results showed that by quantifying this special feature, which is an S-shaped curve near the petioles connection of beet leaves, sugar beet can be discriminated from weeds with an accuracy of 91.65 %. Recalled that this feature is a shape characteristic, therefore, the generalized Hough algorithm must be applied prior to plant canopy development, which is consistent with the critical period of weed control in sugar beet fields.

Sustainable development would be a key solution for climate change and renewable energy plays an important role in this policy. Recently, according to increase of CO2 emission and other relevant impacts, solar energy has been gaining more attentions from policy makers. Thus, compound parabolic concentrators collectors are considered as one of the promising applications from solar thermal advantages. Therefore in this study a non-evacuated CPC collector with 2.5 of concentrating ratio and heat transfer oil as the fluid has been provided and tested under different mass flow rates (3 levels). Experimental results indicate that, outlet temperature is within 80-100oC for all conditions. Moreover, it was concluded that heat losses decrease, when oil mass flow rate descends, presumably wind cooling effects is a dominant factor during test periods. Additionally, extracted differential temperature of oil in the collector was correlated with solar radiation and results proved system compatibility with industrial heat demands.

Testes are composed of very active body tissues, which can be affected by exposure to radiofrequency waves. Age of exposure may also be an important factor. This study was carried out to evaluate morphological parameters of rat sperm exposed to microwave radiation at pre and post puberty.
For this experimental study, 18 adults (2 month years old) and 18 prepuberty (1 month years old) male rats were selected and each group divided in two subgroups, control and test group. Test groups were exposed to 2450 MHZ microwaves produced by microwave oven (LG brand), three times a day, and 30 minute each times. Control groups were kept in laboratory at same temperature and light condition. After 60 days, all animals were killed and testes were removed and epidydimal sperm was used for morphological study.
The result showed a significant decrease in the number of epididymis sperms of test group compared with control group (P=0.042). Percent of dead and abnormal sperms in test group had a statistically significant increase compared with control group (P=0.047) and (0.45). There was no significant difference between mature and prepuberty exposed rats.
Exposure to microwaves leaked of microwave oven has deleterious effect on morphology of epidydimal sperm.

In this study, a three wheel dynamic model refer to a field tractor with an implement was developed to control the tractor in the field accurately. Main difference between a tractor and in-road vehicles is implements connected to the tractor. These implements exert lateral and draft force to the tractor. In order to investigate these kinds of forces, behavior of implements was simulated like a tire. The study was supposed that side slip angle, steering angle and traction of left wheels of tractor are as same as right wheels. In addition a torque was made by draft force moved to the center of gravity of implement. So six wheels traditional model was simplified to three wheels model. The model was simulated by MATLAB software. Results showed that the lateral force and the draft force of implements had effect on the yaw rate and the side slip angle. In addition, controllability of the model was surveyed and results showed that the model have capability of predicting different states of motion in a finite interval of time.

A portable and light pneumatic branch shake system was designed and manufactured in this research for harvesting fruits that can be harvested by shaking branch. Required air flow and electric current are provided for operating system from category containing electrical generator and air compressor on wheelbarrows and portable chassis. Vibration is equipped by programmable logic controller (PLC) for controlling frequency and it is equipped by pantograph system to change amplitude. First farm test was done on olive with three levels of frequency (8، 12 and 16 Hertz) and three times to shaking (5، 10 and 15 seconds) and in constant amplitude of oscillation 5 cm in completely randomized design with four reduplications and second farm test was performed on olive with three levels of frequency (8، 12 and 16 Hertz) and three amplitudes of oscillation (50، 80 and 100 mm) for a fixed period of 5 s in completely randomized design with four reduplication for determining application of branch shake. Some experiments were done for determining static force separating fruit from branch and for comparing it with dynamic force due to performing vibration، as well. The results showed that oscillatory frequency and duration of shaking out have meaningful effect on one percent level on efficiency of shaking system whereas their interaction was not meaningful effect. Comparison of averages showed that increase of the time of vibration didn''t have meaningful effect on percent of harvesting olive in constant oscillation but increase of oscillation in constant time of vibration had meaningful effect on percent of harvesting. Also the result of indicator was based on meaningful effect of amplitude of oscillation on falling olive. And by comparing averages، it was given that falling olive is increased with increasing frequency in constant amplitudes of oscillation. Also، it was not observed meaningful differences between percent of falling olive with increasing amplitude of oscillation from 50 mm to 80 mm in constant frequencies. But when amplitude of oscillation increases from 80 mm to 100 mm، the percent of falling olive meaningfully increases. Finally، concerning by performing 16 Hz frequency and 100 mm amplitude of oscillation for 5 s، 90 percents of olive were separated from branches، therefore they were selected as the best amplitude، frequency and time of vibration.

Experimental work was undertaken to obtain the adsorption isotherms of freeze-dried pomegranate seed powder. Moisture equilibrium data of pomegranate seed were determined using the static gravimetric method. Adsorption Isotherms were determined at 25، 40 and 60°C over a water activity range of 0. 11 to 0. 94. Six isotherm equations including GAB، BET، Iglesias and Chirife، Henderson، Smith، and Oswin were applied for analyzing the experimental data. The constants in the mentioned models were determined and correlated with temperature. The criteria used to evaluate the goodness of fit of each model were Correlation coefficient (R2)، Chi-square (χ2)، mean relative percentage deviation modulus (P) and root mean square error (RMSE). The results showed that the GAB equation gave the best fit to the experimental data. The net isosteric heat of sorption was determined using the Clausius-Clapeyron equation. The heat of sorption values of pomegranate seed powder were found to be large at low moisture content and decreased with an increase in moisture content.

fully instrumented air conditioning laboratory unit capable of controlling drying air temperature and humidity integrated with an instantaneous weighing thin layer drying system was used to investigate the thin layer drying behavior and desorption equilibrium moisture content of canola (Brassica napus L.).To this aim, freshly harvested canola samples with moisture content of about 12±0.5% (d.b.) were dried at temperature levels of 40, 45, 50, 55 °C and absolute air humidity levels of 0.005, 0.01, 0.015, and 0.02 Kg/Kg. The instantaneous grain moisture content was measured by weighing the sample periodically. Drying was continued until canola kernels reached a constant weight to obtain the hygroscopic equilibrium moisture for different combinations of drying air temperature and absolute humidity. To select a suitable model for describing the thin layer drying of canola, experimental drying data were fitted with three thin layer drying models,namely, Page, Modified Page and Two-Term Exponential models. Furthermore,four widely used desorption isotherm models including Chung-Pfost, Modified Chung–Pfost, Modified Oswin, and Modified Smith were used to fit the experimental data of equilibrium moisture content. Finally, non-linear regression analyses were run and based on the highest value for R2 and the lowest value for 2, mean bias error (MBE) and root mean square error (RMSE), the most suitable models for thin layer drying and equilibrium moisture content were determined to be Two-Term Exponential and Modified Smith, respectively.

The application of solar energy for drying cereals and other agricultural commodities has been increasing lately. This is due to the fact that solar energy is free, renewable, inexhaustible and environmentally friendly. This research is a new approach for employing solar energy as the main energy source for drying purposes. The drying test rig was designed, fabricated and evaluated. The grain solar dryer is an active mixed mode type with a semi-continuous discharge system. The rig consists of six solar air collectors, a heating channel, a drying chamber and an air distributing system. Rough rice was selected as cereal grain to be dried in the dryer to evaluate the system of the drying rig. In this research the effect of mass flow rate and time of crop discharge, on the rate of crop drying were evaluated. The experiment was conducted as a factorial experiment on the basis of a completely randomized design with three replications. The first factor was mass flow rate at three levels of 0.011, 0.0066 and 0.0048 kg/m2s and the second factor was the time of crop discharge at two levels of 15 and 30 min. The dryer capacity, the amount of energy consumed (electrical and solar) during drying process, and the efficiency of collectors were also evaluated. According to Duncan's multiples range test, the effects of mass flow rate of drying air, and the interval time of discharge, were highly significant on the moisture content of discharged rough rice. The maximum efficiency of the collectors was 37.13% and the fraction of energy consumed by heating channel during the drying process, compared with solar energy, was 6-8 percent. The maximum capacity of the dryer was about 132 kg of rough rice from 11 AM to 2 PM reducing the initial moisture content from 27% to 13%. On the whole, the evaluation results indicated that the dryer could reduce the moisture content of the crop to the storage safe moisture content during appropriate time with highenergy efficiency.