The present work is a study on the influence of temperature and the velocity of air on the drying kinetics of pineapple slices. The main objective is to define from this drying kinetics rules to help a designer choose...The present work is a study on the influence of temperature and the velocity of air on the drying kinetics of pineapple slices. The main objective is to define from this drying kinetics rules to help a designer choose an adequate principle or drying configuration and optimize the design of dryers adapted to the use of it. The experiments were made in an electric dryer using a parallel flow system. The air was used at three different temperatures （40, 50 and 60 ~C） and at four different velocities （0.27, 0.5, 1 and 1.8 m/s） during the experiment. The results show that an increase of 10 ℃ of the drying temperature reduced the drying time by 45% and increased the drying velocity by 30%. On the set of air velocities tested, it was noticed that the influence of air velocity on drying was more striking at the beginning than at the end of the drying process （variation of less than 20%）. Whatever the variation of parameters during the drying process, the best performance was observed when the products water content during the drying process was between 50% and 80%.展开更多
Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the populati...Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the population economically active. Michoacfin ranks third in national cattle inventory （1,608,523 heads） with fifth place in meat production （145,221 ton/year）. The production model is extended cow-breed, subject to season and availability of food （few rains shortage of forage during drought）, with 0.60 production of breed/cow/year, and a marked traditionalism in the form of production; also a high dependency to food based on the grazing. The inadequate national public policy expressed in the paternalism has limited the adoption of strategies to contribute to the solution of this problem. Therefore this study objective was to design and validate a strategy to increase the number of cow breeding/cow/year to season reproduction program, based on the use of synthetic progesterone ＂melengestrol acetate＂ （MGA） as a technology available, secure, easy to use, low cost and likely to be adoptable to the traditional model of production. Work was done in the dry tropics in the municipalities of Churumuco and Tzitzio, Michoacfin State, Mdxico. Used 133 bovine females with crossbreeding Bos indicus, diagnosed as not pregnant, 6.7 and 6.38 years old respectively for each municipality. Oral doses of 0.05 rag/day/cow of MGA during nine days then exposed to the presence of male. Data were analyzed using analysis of variance of a single way. The results indicate that the delivery rate was 58.33% in Churumuco and 61.86% in Tzitzio. This delivery rate represents an increase of 14%-16% of born per year considering that treated females become pregnant with traditional production system management. We concluded that the MGA is an appropriate strategy to the traditional production of tropical dry in MichoacO, n system that increases the rate of births and is likely to be accepted despite the paternalistic public policy prevailing in the country.展开更多
An approach to design multi-channel cylinder dryer was proposed. The heat transfer performance and flow characteristic under various structural parameters were analyzed. First, an experiment was designed and set up to...An approach to design multi-channel cylinder dryer was proposed. The heat transfer performance and flow characteristic under various structural parameters were analyzed. First, an experiment was designed and set up to measure the condensing heat transfer coefficient and the pressure drop in order to ,~erify the applicability of the Cavallini＇s correlation. Then, the relationship among the count of channels, aspect ratio, spacing ratio, width, height and hydraulic diameter of a channel was given. Finally, the correlation of condensing heat transfer and the homogeneous model was introduced in order to observe the heat transfer performance and flow characteristic of the multi-channel cylinder dryer affected by different structures. The study reveals that the structural parameters including count of channels, aspect ratio, spacing ratio of a channel dramatically influence the condensation heat transfer coefficient and frictional resistance of the steam. Based on the selected paper machine, it is suggested that the overall performance of the multi-channel cylinder dryer is best if the count of channels is 150-200, the aspect ratio is 1 ： 3 and the spacing ratio is 1 ： 1-1 ： 3.展开更多
Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem ar...Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem artichoke is scanned and analyzed by High Performance Liquid Chromatography （HPLC） for quantity of FOS. They are selected for extraction and drying process. Studies on the extraction for a powder making, the conditions are optimum for maximum yield. Experiments manage using a factorial real 2 × 4 × 6 in 2 blocks of Randomized Complete Block Design （RCBD） models. The first factor studies on two types of solvent. The second factor is the four levels of temperature in the extraction with water at 25 ℃, 35 ℃, 50℃ and 60℃ for 30 min. The third factor is the ratio of sample per solvent as 5, 6, 10, 15, 20 and 30 times. The data and comparison of average is analyzed by Duncan＇s New Mutiple Range Test at the significant level 0.05. The concentrated extracts are processed to powder by freeze drying, a hot air and vacuum drying. Optimal conditions control the temperature and time by heating in both vacuum and conventional oven. The results of temperature on the extraction are significantly different at a = 0.05. In drying process with high temperature, the color of product is more yellow （b） and less white （L）. The difference of color value is statistically significant at level a = 0.05. The sensory evaluation of food products are added the extracted powder and attribute by panelist. High level acceptance of product is aspectual about texture and flavor. FOS is the trend of functional foods for health. It is focus on low energy and on obesity including increasing the absorption of calcium.展开更多
文摘The present work is a study on the influence of temperature and the velocity of air on the drying kinetics of pineapple slices. The main objective is to define from this drying kinetics rules to help a designer choose an adequate principle or drying configuration and optimize the design of dryers adapted to the use of it. The experiments were made in an electric dryer using a parallel flow system. The air was used at three different temperatures （40, 50 and 60 ~C） and at four different velocities （0.27, 0.5, 1 and 1.8 m/s） during the experiment. The results show that an increase of 10 ℃ of the drying temperature reduced the drying time by 45% and increased the drying velocity by 30%. On the set of air velocities tested, it was noticed that the influence of air velocity on drying was more striking at the beginning than at the end of the drying process （variation of less than 20%）. Whatever the variation of parameters during the drying process, the best performance was observed when the products water content during the drying process was between 50% and 80%.
文摘Michoacan brings 2.1% of national GDP, which is 12.5% to agriculture, Livestock is the fourth activity in economic importance in the State and develops in 43% of the territory （58,643 km：） using 27% of the population economically active. Michoacfin ranks third in national cattle inventory （1,608,523 heads） with fifth place in meat production （145,221 ton/year）. The production model is extended cow-breed, subject to season and availability of food （few rains shortage of forage during drought）, with 0.60 production of breed/cow/year, and a marked traditionalism in the form of production; also a high dependency to food based on the grazing. The inadequate national public policy expressed in the paternalism has limited the adoption of strategies to contribute to the solution of this problem. Therefore this study objective was to design and validate a strategy to increase the number of cow breeding/cow/year to season reproduction program, based on the use of synthetic progesterone ＂melengestrol acetate＂ （MGA） as a technology available, secure, easy to use, low cost and likely to be adoptable to the traditional model of production. Work was done in the dry tropics in the municipalities of Churumuco and Tzitzio, Michoacfin State, Mdxico. Used 133 bovine females with crossbreeding Bos indicus, diagnosed as not pregnant, 6.7 and 6.38 years old respectively for each municipality. Oral doses of 0.05 rag/day/cow of MGA during nine days then exposed to the presence of male. Data were analyzed using analysis of variance of a single way. The results indicate that the delivery rate was 58.33% in Churumuco and 61.86% in Tzitzio. This delivery rate represents an increase of 14%-16% of born per year considering that treated females become pregnant with traditional production system management. We concluded that the MGA is an appropriate strategy to the traditional production of tropical dry in MichoacO, n system that increases the rate of births and is likely to be accepted despite the paternalistic public policy prevailing in the country.
基金Acknowledgements This project is supported by the National Natural Science Foundation of China （Grant No. 51375286）, Natural Science Basic Research Plan in Shaanxi Province of China （Program No. 2012JZ7002） and the key scientific and technological innovation team fund of Shaanxi Province of China （Program No. 2014KCT- 15）.
文摘An approach to design multi-channel cylinder dryer was proposed. The heat transfer performance and flow characteristic under various structural parameters were analyzed. First, an experiment was designed and set up to measure the condensing heat transfer coefficient and the pressure drop in order to ,~erify the applicability of the Cavallini＇s correlation. Then, the relationship among the count of channels, aspect ratio, spacing ratio, width, height and hydraulic diameter of a channel was given. Finally, the correlation of condensing heat transfer and the homogeneous model was introduced in order to observe the heat transfer performance and flow characteristic of the multi-channel cylinder dryer affected by different structures. The study reveals that the structural parameters including count of channels, aspect ratio, spacing ratio of a channel dramatically influence the condensation heat transfer coefficient and frictional resistance of the steam. Based on the selected paper machine, it is suggested that the overall performance of the multi-channel cylinder dryer is best if the count of channels is 150-200, the aspect ratio is 1 ： 3 and the spacing ratio is 1 ： 1-1 ： 3.
文摘Fructo-oligosaccharide （FOS） is a type of dietary fiber. It can not be digested by enzymes in the body. It also helps to improve a digestion in the intestine, an excretion system and prevent the cancer. Jerusalem artichoke is scanned and analyzed by High Performance Liquid Chromatography （HPLC） for quantity of FOS. They are selected for extraction and drying process. Studies on the extraction for a powder making, the conditions are optimum for maximum yield. Experiments manage using a factorial real 2 × 4 × 6 in 2 blocks of Randomized Complete Block Design （RCBD） models. The first factor studies on two types of solvent. The second factor is the four levels of temperature in the extraction with water at 25 ℃, 35 ℃, 50℃ and 60℃ for 30 min. The third factor is the ratio of sample per solvent as 5, 6, 10, 15, 20 and 30 times. The data and comparison of average is analyzed by Duncan＇s New Mutiple Range Test at the significant level 0.05. The concentrated extracts are processed to powder by freeze drying, a hot air and vacuum drying. Optimal conditions control the temperature and time by heating in both vacuum and conventional oven. The results of temperature on the extraction are significantly different at a = 0.05. In drying process with high temperature, the color of product is more yellow （b） and less white （L）. The difference of color value is statistically significant at level a = 0.05. The sensory evaluation of food products are added the extracted powder and attribute by panelist. High level acceptance of product is aspectual about texture and flavor. FOS is the trend of functional foods for health. It is focus on low energy and on obesity including increasing the absorption of calcium.
