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The aim of the present work was to assess the influence of high-intensity airborne ultrasound application on duration and energetic performance of hot air drying of peppermint leaves. To this end, drying experiments were conducted at constant air flow rate of 1 m s−1 and different temperatures (40, 50, 60 and 70 °C) without and with application of ultrasound power (90, 180, 270 and 360 W). The results showed that the maximum (170.84 MJ kg−1) and the minimum (63.36 MJ kg−1) specific energy consumptions belonged to convective drying at temperature of 40 °C and ultrasonic-assisted drying at 60 °C and 270 W, respectively. Energy efficiency varied from 1.41 to 3.69%. Depending on the power level, application of the ultrasound power at the air temperatures less than 70 °C reduced drying time and improved energetic performance of the process. The obtained findings in this research declare that acoustic power could be effectively used in combination with convective dryers to reduce duration and energy required for drying of heat-sensitive products. • Ultrasound power ability to improve energy efficiency of drying process was studied. • Application of the power reduced the process duration of up to 41%. • At temperatures less than 70 °C, ultrasound power increased the energy efficiency. • The values of energy efficiency ranged from 1.41 to 3.69%. • The power has good ability to reduce the process duration and energy consumption. [ABSTRACT FROM AUTHOR]

This paper aims at presenting a comprehensive perusal on hot air and microwave drying of medicinal herbs through investigating the dehydration behaviour, mathematical modelling, energy characteristics and essential oil yield of peppermint leaves drying. For our study the leaves were dried using microwave at power levels of 200, 400, 600, and 800 W, and hot air at temperatures of 50, 60 and 70 °C. The dehydration process of the leaves in microwave drying method occurred in an accelerating rate period at the start followed by a falling rate period while; convective drying took place in the falling rate period entirely. Six mathematical models were fitted into the experimental data and the Midilli and Kucuk model best described the drying curves. The lowest effective moisture diffusivity (1.809×10 −9 m 2 s −1 ) belonged to hot air drying at 50 °C, while the highest (110.552×10 −9 m 2 s −1 ) belonged to microwave drying at 800 W. The activation energy for microwave and hot air drying was determined to be 1.89 W g −1 and 12.46 K J mol −1 , respectively. Specific energy consumption for microwave and convective drying of the peppermint leaves were ranged from 4.581 to 5.890 M J kg w −1 , and from 42.721 to 64.712 M J kg w −1 , respectively. The maximum and minimum oil yields were obtained from the leaves dried at air temperature of 70 °C and microwave power at 800 W, respectively. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the energy consumption and evaluation of inputs for honey production in Shahrekord city in the Chaharmahal Va Bakhtiary province, Iran to investigate the efficiency of energy consumption and to make an economic analysis of honey production. Data used in this study were obtained from 80 beekeepers using a face to face questionnaire method. The sample bee keepings were selected through a stratified random sampling technique. The following results were obtained at the end of the study: with 54.43% the input of sugar is the highest within the energy equivalences of input used in honey production. This is followed by electricity and transportation with 14.02% and 13.84%, respectively. The total energy inputs, total energy outputs, input–output energy ratio and productivities were 28941.51 MJ hive −1 , 15264 MJ hive −1 , 0.54 and 0.04, respectively. The results indicated that all of the inputs affected the yield significantly, except electricity. The fuel (2815.5 MJ hive −1 ) and sugar (15292.2 MJ hive −1 ) were affected significantly with 0.547 and 0.459 coefficients, respectively. The input–output energy ratio shows that the inputs used in the production of honey are not used efficiently. Extension activities are needed to improve the efficiency of energy consumption in honey production and to employ environmentally friendly agricultural management practices and production methods. [ABSTRACT FROM AUTHOR]