جستجوی مقالات مرتبط با کلیدواژه « Thermography » در نشریات گروه « مکانیزاسیون کشاورزی »

Since white berry has much medical and edible benefit, it is known as a popular fruit. This research is carried out in order to classify ripe and unripe berries from each other using active thermography method. In this research 70 berries have been used as experimental samples randomly selected from a tree. They were sorted to “ripe” and “unripe” class by 5 expert people with attention to the color and texture of fruits. The temperature changes of samples by heat shock induction were recorded with a thermal camera and coefficients of first order, second order and logarithmic equations fitted to temperature-time graphs were employed for classification in MATLAB software. Using Principal Component Analysis (PCA) method, in MATLAB software, causes to use only first order equation coefficients, with an accuracy of 90 percent. Using the results of this research, the speed and accuracy of classification can be effectively increased in berry classification lines.

Energy survey is always a critical stage of the management in the process engineering facilities. As the first and crucial step toward technical, thermo engineering and economic improvement and optimization of sugar production process, energy audit is conducted experimentally and analytically in the evaporation line of Urmia sugar factory. To yield such a purpose, based on the thermodynamic analysis and measurements, the share of each equipment in energy and exergy loss is precisely determined. Moreover, detail parameters have been monitored in the different surfaces of each equipment. Thermography method is applied to study the insulation condition and heat loss level. Maximum energy and exergy loss is assigned to top view surfaces. Lateral surfaces dissipated much energy compared to bottom view surfaces. Results show that the heat loss is occurred mostly through radiation transfer by 67 % and the rest is experienced by convection transfer as 33 %. Total thermal power dissipation of the evaporation line to the medium is estimated to be 186.03 kW which is calculated on the basis of heat convection coefficient and heat radiation. Results prove that the dominant heat loss is respectively related to first evaporator, the second and third shell and tube heat exchangers. Furthermore, the maximum exergy loss is occurred in pre heating section, where more than half of the total exergy loss belongs to shell and tube heat exchangers. Accumulated exergy through the evaporation line is estimated to be 30.86 kW stating the energy effectiveness gap of the whole system comprising subsystems such as individual evaporators or heat exchangers. The research results would be implemented in the future management decisions on sugar production cost reduction. The research methodology and obtained technical details can be used in the future investigations on sustainable development policies in governmental section.

Identifying and sorting healthy agricultural products from damaged products reduces casualties and losses caused by the spread of disease to unhealthy samples. Due to Iran's insignificant contribution to agricultural exports, the use of non-destructive methods, such as thermography in the sorting and grading of the fruit, is necessary. In this research, active thermography method was used to identify the Red delicious cultivars of apple. In order to study the temperature variations of apples, used a factorial experiment was conducted in a randomized complete design with three independent variables including bruises, heating temperature and cooling time. The results of variance analysis of surface temperature of healthy and bruise apples showed that the levels of bruises, heating temperature and cooling time on the surface temperature of bruises apples had a significant effect at 1% probability. Statistical and texture features were extracted from thermal images and the artificial neural network method was used to classify two healthy classes and bruised. Neural network accuracy with a hidden layer and 15 neurons was obtained 100%. The results indicate that the difference in temperature of the bruised and sound tissue can be considered as a criterion for the classification of apples. Also, Active thermography is an efficient and high-tech method for detecting apple bruises.

Potato dry rot is one of the most detrimental diseases affecting on potato tubers caused by Fusarium Solani fungus. In order to prevent the expansion of potato dry rot and the losses caused by this disease, the fungi must be detected and destroyed. The common methods for detecting contaminations are time-consuming, expensive and painstaking. In this study, a fast and reliable method has been presented based on active thermography technology. This method was used to detect the healthy tubers from contaminated ones and to classify the different stages of contamination (1 to 9 day after infection). In the active thermography, two heating temperature levels and four cooling time levels were applied on the samples. The results of variance analysis and compare mean of the average temperature differences between the surfaces of the healthy and contaminated tubers indicated that 90 oC heating temperature and 40 s cooling time of the samples was the best treatment for detecting healthy and contaminated tubers. For evaluating the classifier performance, statistical indicators such as accuracy, precision, sensitivity and specificity were calculated. The total accuracy of the classifier was 96.67%.

In order to decrease water consumption in agricultural sector, deficit irrigation has been suggested. For preventing a heavy loss in crop yield, management of water stress is essential. Common methods for measuring plant water stress such as stomatal conductance are time-consuming and require specialized labor and a large number of measurement. Temperature of leaf or canopy surface can be an indicator of stomatal conductance or plant water stress. Canopy temperature is not only affected by stomatal conductance, but also with environmental conditions such as air temperature or vapor pressure deficit. Crop water stress index (CWSI) is recently proposed to solve these problems. By comparing the canopy temperature with two reference temperatures in crop water stress index, the effect of environmental conditions can be minimized. Thermography is a non-contact approach toward surface temperature measurement without interfering with plant activities. The general goal of this study was to obtain CWSI using thermal images and to evaluate the potential of this method for predicting the stomatal conductance. In order to achieve this goal, thermal images from olive trees under five deficit irrigation treatments with three replications were obtained. The results showed a significant (R2ADJ = 0.83) relationship between CWSI and the stomatal conductance