To simulate the concrete shrinkage in varying temperature and moisture environments, a simulate procedure comprising an analytical process and a finite element analysis is proposed based on the coupled partial differe...To simulate the concrete shrinkage in varying temperature and moisture environments, a simulate procedure comprising an analytical process and a finite element analysis is proposed based on the coupled partial differential equations describing heat and moisture transfer in a porous medium. Using the Laplace transformation method and transfer function to simplify and solve the coupled equations in Laplace domain, the moisture and temperature distribution in time domain are obtained by inverse Laplace transformation. The shrinkage deformations of concrete are numerically simulated by the finite element method （FEM） based on the obtained temperature and moisture distribution. This approach avoids the complex eigenvalues, coupling difficulty and low accuracy found in other solving methods, and also effectively calculates the moisture induced shrinkage which is almost impossible using familiar FEM software. The validity of the simulation procedure is verified by Hundt＇s test data. The results reveal that the proposed approach can be considered a reliable and efficient method to simulate the coupling moisture and temperature shrinkage of concrete.展开更多
Foxtail millet, originated from China and now cultivated worldwide, is a kind of high dietary fiber whole grain food, and has a high level of vitamins and proteins. Furthermore, foxtail millet has many positive effect...Foxtail millet, originated from China and now cultivated worldwide, is a kind of high dietary fiber whole grain food, and has a high level of vitamins and proteins. Furthermore, foxtail millet has many positive effects on the adjuvant treatment of diabetes, cancer, and cardiovascular diseases because of the abundance in polyphenols. Nonetheless, foxtail millet has poor processing characteristics due to the absence of gluten, restricting the development of foxtail millet products. Studies have demonstrated that heat-moisture treatment, extrusion, superfine grinding, and microbial fermentation are promising methods to improve the processing qualities of foxtail millet. Heat-moisture treatment is helpful to increase the content of resistant starch but has less influence on other components, further reduce the GI value of foxtail millet. The extrusion has positive effects on improving the solubility of foxtail millet starch and increasing the contents of polyunsaturated fatty acid, linoleic and linolenic acids, and adverse effects on reducing the solubility of foxtail millet proteins and causing losses of nutrients due to Maillard reaction. Superfine grinding can reduce the particle size of foxtail millet to obtain a better mouthfeel of foxtail millet products. The superfine foxtail millet flour has better solubility, higher freeze-thaw stability, and lower gelatinization temperature. Microbial fermentation contributes positively to reducing the molecular weight and retrogradation value of foxtail millet starch, degrading rapidly digested starch, and improving the digestibility of foxtail millet protein. This paper briefly introduced the effects of different processing methods on foxtail millet nutrients, aiming to provide references for increasing the variety and improving the quality of foxtail millet products.展开更多
The skin heat loss(heat flow)of summer fabrics duringthe course of sweating--evaporating--drying is mea-sured by an apparatus specially made for the purpose.Itis pointed out that:the dynamic heat-moisture comfortcan b...The skin heat loss(heat flow)of summer fabrics duringthe course of sweating--evaporating--drying is mea-sured by an apparatus specially made for the purpose.Itis pointed out that:the dynamic heat-moisture comfortcan be described by evaporating rate or time required fordrying out of a certain amount of sweat.The evaporat-ing rate is influenced by the hygroscopic property andthickness of the fabric,the larger the hygroscopicity ofthe fabric with the same thickness,the smaller the evap-orating rate of the perspirated sweat.展开更多
To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock te...To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock temperature decreases quickly at the initial stage, and reduces slowly to be a constant value finally for transient heat-moisture transfer. The quasi-steady surface temperature of wet airway is lower than that of dry airway due to the moisture transfer. The diffusion radius is less than the cooling radius owing to the large diffusion resistance. The outlet airflow enthalpy of wet airway is much larger than that of dry airway. Latent heat caused by the moisture transfer plays a significant role in a deep thermal environment. For periodic heat-moisture transfer, temperature, humidity and enthalpy of outlet airflow and rock temperature also change periodically. The wave amplitude of rock temperature decreases gradually with increasing distance away from the airway surface, and the wave phase of rock temperature is also behind that of airflow. Moreover, direction of the heat-moisture transfer between airway and airflow is bidirectional, which is different from results of transient transfer.展开更多
The temperature and humidity of the microclimatic zone of summer fabrics in the course of sweating — evaporating — drying were measured with an apparatus specially made for the purpose. It is pointed out that temper...The temperature and humidity of the microclimatic zone of summer fabrics in the course of sweating — evaporating — drying were measured with an apparatus specially made for the purpose. It is pointed out that temperature and humidity changes in quantitative perspiration evaporation process in the microclimatic zone can express the dynamic heat-moisture comfortability. Characteristic values include temperature decline speed, temperature rising speed, humidity rising speed, humidity balance value, and humidity decline speed. Fabrics with good air permeability are beneficial to improving comfortability of summer fabrics, while temperature rising speed and humidity decline speed in the microclimatic zone of thick and heavy fabrics with good hygroscopicity are relatively slow. Through comparing fabrics dynamic heat-moisture curves obtained respectively with Microclimatic Method and Heat Loss Method, the two methods are identical essentially.展开更多
Heat moisture treatment is safe and non-chemical use method for modifying physicochemical properties and digestibility of starch.Slow starch digestion in rice product would provide numerous health benefi ts for the co...Heat moisture treatment is safe and non-chemical use method for modifying physicochemical properties and digestibility of starch.Slow starch digestion in rice product would provide numerous health benefi ts for the consumers.This study investigated the heat-moisture treatment to the raw paddy rice at 60 and 80ºC for 4 and 24 h,and their effects on the attributes of cooked rice.The fi rmness,adhesiveness,starch hydrolysis and morphological changes during in vitro digestion were examined.Results showed that heat-moisture treatment to raw paddy rice for 24 h signifi cantly reduced the moisture content and could increase the total starch content of the rice grain.The apparent amylose content ranged from 23.83%to 25.65%at the variation in the values between treated and untreated rice.Enhancement in the firmness and reduction in the starch hydrolysis was found in rice treated by longer heating time of 24 h.Meanwhile,the adhesiveness of cooked rice was decreased when increasing the heating temperature.The morphological observation showed that the treated rice exhibited a honey-comb-like structure during simulated gastric digestion,while the untreated rice displayed a non-uniform structure.Noteworthy,the porous structure observed in all digested rice grains during simulated small intestinal digestion could favor the starch hydrolysis.This study showed that the heat-moisture treatment to the raw paddy rice at certain conditions obviously influenced the attributes of cooked rice,especially on the starch hydrolysis,which would provide a fundamental knowledge to enable development and improvement of slow digestion rice products.展开更多
This paper in the light of the structure parameters of the ramie fabric to research and evaluation it＇s heart-moisture comfort. Selected 15 kinds of ramie fabric to test the average density, the thickness, the tightn...This paper in the light of the structure parameters of the ramie fabric to research and evaluation it＇s heart-moisture comfort. Selected 15 kinds of ramie fabric to test the average density, the thickness, the tightness, the heat rate, the heat transfer coefficient, the Clo, the air permeability, the water vapor permeability and other performance index, used SPSS factor analysis to explore the main influence factors of porous ramie fabric＇s heat moisture comfort. Results shows that： the main influence factors of ramie fabric＇s heat-moisture is the heat preservation material, the air permeability and the moisture permeability, get the equation of porous ramie fabric＇ s heat-moisture comfort： F=0.45855y1＋0.30588y2＋0.13549y3, evaluated and sorted the sample fabric＇ s heat-moisture comfort.展开更多
基金The National Natural Science Foundation of China(No50539040)the Trans-Century Training Programme Foundation forthe Talents by the State Education Commission (NoNCET-05-0473)
文摘To simulate the concrete shrinkage in varying temperature and moisture environments, a simulate procedure comprising an analytical process and a finite element analysis is proposed based on the coupled partial differential equations describing heat and moisture transfer in a porous medium. Using the Laplace transformation method and transfer function to simplify and solve the coupled equations in Laplace domain, the moisture and temperature distribution in time domain are obtained by inverse Laplace transformation. The shrinkage deformations of concrete are numerically simulated by the finite element method （FEM） based on the obtained temperature and moisture distribution. This approach avoids the complex eigenvalues, coupling difficulty and low accuracy found in other solving methods, and also effectively calculates the moisture induced shrinkage which is almost impossible using familiar FEM software. The validity of the simulation procedure is verified by Hundt＇s test data. The results reveal that the proposed approach can be considered a reliable and efficient method to simulate the coupling moisture and temperature shrinkage of concrete.
基金supported by the Key scientific and technological project of Henan Province(No.202102110143)State Scholarship Fund of China Scholarship Council(No.202008410106)。
文摘Foxtail millet, originated from China and now cultivated worldwide, is a kind of high dietary fiber whole grain food, and has a high level of vitamins and proteins. Furthermore, foxtail millet has many positive effects on the adjuvant treatment of diabetes, cancer, and cardiovascular diseases because of the abundance in polyphenols. Nonetheless, foxtail millet has poor processing characteristics due to the absence of gluten, restricting the development of foxtail millet products. Studies have demonstrated that heat-moisture treatment, extrusion, superfine grinding, and microbial fermentation are promising methods to improve the processing qualities of foxtail millet. Heat-moisture treatment is helpful to increase the content of resistant starch but has less influence on other components, further reduce the GI value of foxtail millet. The extrusion has positive effects on improving the solubility of foxtail millet starch and increasing the contents of polyunsaturated fatty acid, linoleic and linolenic acids, and adverse effects on reducing the solubility of foxtail millet proteins and causing losses of nutrients due to Maillard reaction. Superfine grinding can reduce the particle size of foxtail millet to obtain a better mouthfeel of foxtail millet products. The superfine foxtail millet flour has better solubility, higher freeze-thaw stability, and lower gelatinization temperature. Microbial fermentation contributes positively to reducing the molecular weight and retrogradation value of foxtail millet starch, degrading rapidly digested starch, and improving the digestibility of foxtail millet protein. This paper briefly introduced the effects of different processing methods on foxtail millet nutrients, aiming to provide references for increasing the variety and improving the quality of foxtail millet products.
文摘The skin heat loss(heat flow)of summer fabrics duringthe course of sweating--evaporating--drying is mea-sured by an apparatus specially made for the purpose.Itis pointed out that:the dynamic heat-moisture comfortcan be described by evaporating rate or time required fordrying out of a certain amount of sweat.The evaporat-ing rate is influenced by the hygroscopic property andthickness of the fabric,the larger the hygroscopicity ofthe fabric with the same thickness,the smaller the evap-orating rate of the perspirated sweat.
基金Foundation item： Project（2012CB026103） supported by the National Basic Research Program of China Project（51204170） supported by the National Natural Science Foundation of China+2 种基金 Project（2011M500974） supported by Postdoctoral Science Foundation of China Project （2011QNA16） supported by Fundamental Research Funds for the Central Universities, China Project（PDll01） supported by Postdoctoral Foundation of State Key Laboratory for Geomechanics and Deep Underground Engineering, China
文摘To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock temperature decreases quickly at the initial stage, and reduces slowly to be a constant value finally for transient heat-moisture transfer. The quasi-steady surface temperature of wet airway is lower than that of dry airway due to the moisture transfer. The diffusion radius is less than the cooling radius owing to the large diffusion resistance. The outlet airflow enthalpy of wet airway is much larger than that of dry airway. Latent heat caused by the moisture transfer plays a significant role in a deep thermal environment. For periodic heat-moisture transfer, temperature, humidity and enthalpy of outlet airflow and rock temperature also change periodically. The wave amplitude of rock temperature decreases gradually with increasing distance away from the airway surface, and the wave phase of rock temperature is also behind that of airflow. Moreover, direction of the heat-moisture transfer between airway and airflow is bidirectional, which is different from results of transient transfer.
文摘The temperature and humidity of the microclimatic zone of summer fabrics in the course of sweating — evaporating — drying were measured with an apparatus specially made for the purpose. It is pointed out that temperature and humidity changes in quantitative perspiration evaporation process in the microclimatic zone can express the dynamic heat-moisture comfortability. Characteristic values include temperature decline speed, temperature rising speed, humidity rising speed, humidity balance value, and humidity decline speed. Fabrics with good air permeability are beneficial to improving comfortability of summer fabrics, while temperature rising speed and humidity decline speed in the microclimatic zone of thick and heavy fabrics with good hygroscopicity are relatively slow. Through comparing fabrics dynamic heat-moisture curves obtained respectively with Microclimatic Method and Heat Loss Method, the two methods are identical essentially.
基金supported by a grant from the Project of the NARO Bio-oriented Technology Research Advancement Institution for Research Program on Development of Innovative Technology.The grant number was 01010B.
文摘Heat moisture treatment is safe and non-chemical use method for modifying physicochemical properties and digestibility of starch.Slow starch digestion in rice product would provide numerous health benefi ts for the consumers.This study investigated the heat-moisture treatment to the raw paddy rice at 60 and 80ºC for 4 and 24 h,and their effects on the attributes of cooked rice.The fi rmness,adhesiveness,starch hydrolysis and morphological changes during in vitro digestion were examined.Results showed that heat-moisture treatment to raw paddy rice for 24 h signifi cantly reduced the moisture content and could increase the total starch content of the rice grain.The apparent amylose content ranged from 23.83%to 25.65%at the variation in the values between treated and untreated rice.Enhancement in the firmness and reduction in the starch hydrolysis was found in rice treated by longer heating time of 24 h.Meanwhile,the adhesiveness of cooked rice was decreased when increasing the heating temperature.The morphological observation showed that the treated rice exhibited a honey-comb-like structure during simulated gastric digestion,while the untreated rice displayed a non-uniform structure.Noteworthy,the porous structure observed in all digested rice grains during simulated small intestinal digestion could favor the starch hydrolysis.This study showed that the heat-moisture treatment to the raw paddy rice at certain conditions obviously influenced the attributes of cooked rice,especially on the starch hydrolysis,which would provide a fundamental knowledge to enable development and improvement of slow digestion rice products.
文摘This paper in the light of the structure parameters of the ramie fabric to research and evaluation it＇s heart-moisture comfort. Selected 15 kinds of ramie fabric to test the average density, the thickness, the tightness, the heat rate, the heat transfer coefficient, the Clo, the air permeability, the water vapor permeability and other performance index, used SPSS factor analysis to explore the main influence factors of porous ramie fabric＇s heat moisture comfort. Results shows that： the main influence factors of ramie fabric＇s heat-moisture is the heat preservation material, the air permeability and the moisture permeability, get the equation of porous ramie fabric＇ s heat-moisture comfort： F=0.45855y1＋0.30588y2＋0.13549y3, evaluated and sorted the sample fabric＇ s heat-moisture comfort.
