Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under di...Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under different conditions. As an additive and strengthening agent,展开更多
The study evaluates the energy consumption of both wet and dry processes cement manufacturing plant in Nigeria. Enrgy consumption data collected for the period 2003 to 2011 were used to estimate the energy consumption...The study evaluates the energy consumption of both wet and dry processes cement manufacturing plant in Nigeria. Enrgy consumption data collected for the period 2003 to 2011 were used to estimate the energy consumption of the crushing, milling, agitation, burning, grinding and bagging operations. The total energy evaluation was based on the three primary energy sources which include electrical, combustion and human. The total estimated energy intensities were 6545 MJ/ton and 4197 MJ/ton for wet and dry processes respectively. The percentage consumption of energy in each operation is 93.68 and 90.34% (burning), 2.11 and 4.33% (milling), 0.43 and 0.67% (crushing), 1.39 and 0% (agitation), 2.12 and 3.90% (grinding), and 0.27 and 0.75% (bagging) of the total energy inputs for the wet and dry processes respectively. Furthermore, the average total energy cost of production showed that wet process is approximately 40% more cost intensive in cement production than the dry process while at the same time it is cost effective to run production on energy through gas powered plant than the national grid.展开更多
The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of po...The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of poly(ethylene oxide)(PEO)droplets using a gold nanoparticle tracer,where the heterogeneous flow field in different regions was illustrated.This demonstrates that the gold nanoparticles at either the center or the edge regions of the droplet exhibit anisotropic kinematic behavior.At early stage,Marangoni backflow causes gold nanoparticles to move towards the edge firstly,and the circles back towards the droplet center after arriving the contact line with a sudden increase in z axis for 10.4μm,indicating the scale of the upward-moving microscopic flow vortices.This phenomenon does not occur in water droplets in the absence of polymers.The gold nanoparticles underwent Brownian-like motion at the center of the PEO droplet or water droplet owing to the low perturbation of the flow field.At the late stage of pinning of the PEO droplets,the motion showed multiple reverses in the direction of the gold nanoparticles,indicating the complexity of the flow field.This study enhances the understanding of the drying dynamics of polymer solution droplets and offers valuable insights into the fabrication of surface materials.展开更多
Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their perform...Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their performance,electrode fabrication techniques are critical aspects influencing the overall capabilities of supercapacitors.Herein,we aim to shed light on the advantages offered by dry electrode processing for advanced supercapacitors.Notably,our study explores the performance of these electrodes in three different types of electrolytes:organic,ionic liquids,and quasi-solid states.By examining the impact of dry electrode processing on various electrode and electrolyte systems,we show valuable insights into the versatility and efficacy of this technique.The supercapacitors employing dry electrodes demonstrated significant improvements compared with conventional wet electrodes,with a lifespan extension of+45%in organic,+192%in ionic liquids,and+84%in quasi-solid electrolytes.Moreover,the increased electrode densities achievable through the dry approach directly translate to improved volumetric outputs,enhancing energy storage capacities within compact form factors.Notably,dry electrode-prepared supercapacitors outperformed their wet electrode counterparts,exhibiting a higher energy density of 6.1 Wh cm^(-3)compared with 4.7 Wh cm^(-3)at a high power density of 195Wcm^(-3),marking a substantial 28%energy improvement in the quasi-solid electrolyte.展开更多
Biomaterial will shrink during the drying process. The characteristics of shrinkage and rehydration of fresh peas were studied. Drying curves, shrinkage and rehydration curves of peas without seed coats and whole peas...Biomaterial will shrink during the drying process. The characteristics of shrinkage and rehydration of fresh peas were studied. Drying curves, shrinkage and rehydration curves of peas without seed coats and whole peas were compared. In addition, different volumetric shrinkage coefficients were obtained and discussed. The results show that seed coats resist moisture movement not only from inside to outside but also from outside to inside during different drying conditions. During a seed’s drying process, the drying curve is similar to the shrinkage curve. The higher the heat flux is, the less drying time is needed, and in the meantime, volume would shrink more and more intensively. Dried media will break easily at high heat flux. When we create a drying regime, both drying speed and the quality of dried media should be considered.展开更多
A numerical simulation for a model of wood drying process is considered. The model is given by a couple of nonlinear differential equations. One is a nonlinear parabolic equation and the other one is a nonlinear ordin...A numerical simulation for a model of wood drying process is considered. The model is given by a couple of nonlinear differential equations. One is a nonlinear parabolic equation and the other one is a nonlinear ordinary equation. A difference scheme is derived by the method of reduction of order. First, a new variable is introduced and the original problem is rewritten into a system of the first-order differential equations. Secondly, a difference scheme is constructed for the later problem. The solvability, stability and convergence of the difference scheme are proved by the energy method. The convergence order of the difference scheme is secondorder both in time and in space. A prior error estimate is put forward. The new variable is put aside to reduce the computational cost. A numerical example testifies the theoretical result.展开更多
A particular porosity method named ＂slot method＂ is implemented in a depth-integrated shallow water flow model （DIVAST） to simulate wetting and drying processes. Discussed is the relationship between the shape fac...A particular porosity method named ＂slot method＂ is implemented in a depth-integrated shallow water flow model （DIVAST） to simulate wetting and drying processes. Discussed is the relationship between the shape factors of the ＂slot＂ and the preset depth used in ＂wetting-drying＂ algorithm. Two typical tests are conducted to examine the performance of the method with the effect of the shape factors of the ＂slot＂ being checked in detail in the first test. Numerical results demonstrate that： 1 ） no additional effort to improve the finite difference scheme is needed to implement ＂slot method＂ in DIVAST, and 2） ＂slot method＂ will simulate wetting and diying processes correctly if the shape factors of the ＂slot＂ being selected properly.展开更多
A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utiliz...A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utilized as the template to in situ synthesize silver nanoparticles(AgNPs).The effects of drying methods including freeze-drying,heat drying and air drying,on the microstructures and physical properties of BC,as well as the silver contents and the antibacterial performances of the BC/AgNPs composites were investigated.It was found that the AgNPs impregnated on the dried BC films were inclined to achieve a faster silver releasing rate than the wet one,which was suitable for acute traumas treatment.展开更多
Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually prese...Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.展开更多
OBJECTIVE： To study the effects of the drying processing in terms operational parameters on the bio- active constituents of six YuanzhJ （Radix Palygalae） samples across China. METHODS： Six Yuanzhi （Radix Palygala...OBJECTIVE： To study the effects of the drying processing in terms operational parameters on the bio- active constituents of six YuanzhJ （Radix Palygalae） samples across China. METHODS： Six Yuanzhi （Radix Palygalae） samples were investigated using thermogravimetry analysis. The heating courses were set in two ways： the temperature-programmed process from room temperature to 150℃ ,and the constant-temperature course at 50℃, 70℃ and 90℃. RESULTS： The peak temperature of six Yuanzhi （Radix Palygalae） samples ranged from 78℃ to 88℃. The mass loss rate of Yuanzhi （Radix Palygalae） alcohol-soluble extract was significantly increased when heated at 90℃. Four types of bioactive ingredients were detected in volatile oils of Yuanzhi （Radix Palygalae） sample from Shanxi province by Gas Chromatography-mass spectrometry analysis. Fourier Transform Infrared Spectroscopy results showed that the drying temperature exerted a great influence on types and amount of ingredients of Yuanzhi （Radix Palygalae）. The kinetic study showed that the constant-temperature drying process of Yuanzhi Radix Palygalae） samples could be well de- scribed by the Page Model, especially for the drying process at 50~C, in which R2 and SD values were more than 0.98 and less than 0.04, respectively.The drying constant k of three Yuanzhi （Radix Palygalae） samples from Shanxi, Gansu and Shaanxi provinces in China was corresponding to the Arrhenius equation, and their activation energies were 28.07, 2.5.38 and 21.48 kJ/mol, respectively. CONCLUSION： The drying process of Yuanzhi （Radix Palygalae） was very important for bioactive ingredients improvement in Yuanzhi （Radix Palygalae）. Temperature was a thermodynamic property significantly affecting the process.展开更多
[Objectives]To determine the drying process of different functional rhubarbs.[Methods]The contents of tannins,bianthrone,free anthraquinones and combined anthraquinones in medicinal rhubarb were determined by HPLC.The...[Objectives]To determine the drying process of different functional rhubarbs.[Methods]The contents of tannins,bianthrone,free anthraquinones and combined anthraquinones in medicinal rhubarb were determined by HPLC.The results were analyzed by two-way analysis of variance.[Results]Under different drying conditions,the contents of tannins,bianthrone,free anthraquinones and combined anthraquinones in medicinal rhubarb were significantly different.Taking the tannins content as the index,the optimum drying condition of the rhizome is 1 cm thick,dried at 60℃,the root is cut 1 cm thick,and dried at 30℃;the bianthrone content is used as an indicator,the rhizome is optimally dried.The condition is to cut 1 cm thick,dry at 60℃,the root is cut to 5 cm thick,and dried at 40℃;the free anthraquinones content is used as an index,and the optimum drying condition of the rhizome is 3 cm thick and dried at 50℃.The root is cut to a thickness of 3 cm and dried at 30℃.The combine anthraquinones content is used as an indicator.The optimum drying conditions for the rhizome are 5 cm thick,dried at 40℃,and the root is cut to 5 cm thick and dried at 70℃.[Conclusions]Different functional components of rhubarb have different directional processing methods.The drying process can reduce the drying temperature or increase the thickness of the slice,and the directional processing of the diarrhea-type rhubarb can be processed.The drying process can be carried out by increasing the drying temperature or reducing the thickness of the slice directed processing of heat-clearing and purging-fire rhubarb.展开更多
Carbon aerogels were synthesized via ambient pressure drying process using resorcinolformaldehyde as precursor and P123 to strengthen their skeletons. CO2 activation technology was implemented to improve surface areas...Carbon aerogels were synthesized via ambient pressure drying process using resorcinolformaldehyde as precursor and P123 to strengthen their skeletons. CO2 activation technology was implemented to improve surface areas and adjust pore size distribution. The synthesis process was optimized, and the morphology, structure, adsorption properties and electrochemical behavior of different samples were characterized. The CO2-activated samples achieved a high specific capacitance of 129.2 F/g in 6 M KOH electrolytes at the current density of 1 m A/cm^2 within the voltage range of 0-0.8 V. The optimized activation temperature and duration were determined to be 950 ℃ and 4 h, respectively.展开更多
This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chlo...This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.展开更多
Drying of the banana in the hot water has a negative impact on the quality of the product and drying effect. The purposes of this study are increasing the drying rate, using the relatively low temperature to improve t...Drying of the banana in the hot water has a negative impact on the quality of the product and drying effect. The purposes of this study are increasing the drying rate, using the relatively low temperature to improve the quality (40℃, 50℃ and 60℃) and investigate the use of electromagnetic waves to increase the drying speed. Therefore, experiments are performed using 5 kHz,10 kHz and 15 kHz low frequency electromagnetic waves in the air velocity values of 0.5 m/s, 1 m/s, 1.5 m/s and 2 m/s and 40℃, 50℃, 60℃ centigrade degrees of air blast in a special compartment. Mathematical model of the drying process has been created as using the electrical circuits methods and experimental results. As a result, a simple equation describing the drying process has been obtained. Nonlinear expression of the diffusion coefficient for a different situation in this equation has been identified for the first time. The obtained theoretical results and experimental results have been provided a good agreement. This study is considered to be useful for all studies in the drying area.展开更多
A coupling model between the canopy layer(CL) and atmospheric boundary layer (ABL) for the study of dry deposition velocity is developed. The model consists of six parts: chemical species conservation equation includi...A coupling model between the canopy layer(CL) and atmospheric boundary layer (ABL) for the study of dry deposition velocity is developed. The model consists of six parts: chemical species conservation equation including absorptive factor; the species uptake action including detailed vertical variation of absorptive element in CL; momentum exchange in CL which is represented by a first-order closure momentum equation with an additional larger-scale diffusive term; momentum exchange in ABL which is described by a complete set of the ABL turbulent statistic parameters; absorptivity (or solubility or reflection) at the surface including effects of the physical and chemical characters of the species, land type, seasonal and diurnal variations of the meteorological variables; and deposition velocity derived by distributions of the species with height in CL. Variational rules of the concentration and deposition velocity with both height and time are simulated with the model for both corn and forest canopies. Results predicted with the bulk deposition velocity derived in the paper consist well with experimental data.展开更多
In this study the effect of initial parameters such as inlet gas temperature, initial particles temperature and gas velocity on temperature changes of solid particles and outlet gas temperature in a fluidized bed drye...In this study the effect of initial parameters such as inlet gas temperature, initial particles temperature and gas velocity on temperature changes of solid particles and outlet gas temperature in a fluidized bed dryer was studied. For testing, an experimental setup was established. With combination of air and Colza seeds belonging to D groups of the Geldart classification (Geldart, 1986) fluidization regime was carried out. With five test series with maintaining the inlet gas temperature, solid particle temperature and outlet gas temperature during time were carefully measured. To analyze these data by using regression analysis to predict solid particle and outlet gas temperature, 2 correlations on initial pa-rameters were presented. The result has shown that temperature gradients in the beginning of fluidization, is very high and therefore the exponential functions in the regression model is used to predict the temperature changes.展开更多
Drying processing of Habanero chili was improved, through solar energy usage. Habanero chili is a notable seasonal product being drying such important for Mexican producers; this process is expensive and wasteful of e...Drying processing of Habanero chili was improved, through solar energy usage. Habanero chili is a notable seasonal product being drying such important for Mexican producers; this process is expensive and wasteful of energy. A feasibility analysis was developed, to determine the market tendency and the optimal drying conditions for redesign Habanero chili drying process, through a hybrid solar-electric energy usage. The new drying process would be held in two stages： （a） an open solar dryer was used; （b） an existing pilot fluidized bed dryer was adapted with a low temperature solar collector for air heating. Habanero chili was dehydrated from 90% to 5% moisture in 10.3 h, with good quality product, available for commercialization. A reduction in the average drying time of 50% was obtained, also, in the energy usage of 77% in the fluidized bed dryer, with an energy saving of 0.52 kg of natural gas per kg of fresh Habanero chili. An innovative sustainable efficient drying process was developed, and will be strategic to expand the market for Habanero chili with low energy cost.展开更多
The aim of this paper is to select the best location for the construction of a dry port in Niger which is a land locked country (LLC). Niger is located in the Sahel and has a land area of 1,267,000 square kilometers [...The aim of this paper is to select the best location for the construction of a dry port in Niger which is a land locked country (LLC). Niger is located in the Sahel and has a land area of 1,267,000 square kilometers [1], with the closest port being port of Cotonou in Benin. The transport corridor from Niamey to Cotonou is approximately 1036 km long [2]. It is estimated that this corridor carries about 40 percent of Niger’s overseas trade traffic [3]. In this work, the Analytic Network Process (ANP) model is used to determine the optimal location of the dry port, among three major cities: Niamey (capital city), Dosso and Gaya. From the application of this selection model, Dosso was selected as the best location for the location of the dry port, while Gaya and Niamey were placed second and third respectively. The results obtained in this work strongly confirm the decision of the government of Niger to construct a dry port in Dosso, a project that commenced in 2010 and is still in progress.展开更多
The solar bubble dryer (SBD) is a convenient and better option to traditional open sun drying commonly practiced by smallholder farmers in Ghana and other developing countries. However, to operate the SBD, one is face...The solar bubble dryer (SBD) is a convenient and better option to traditional open sun drying commonly practiced by smallholder farmers in Ghana and other developing countries. However, to operate the SBD, one is faced with the challenge of frequent mixing of grains using a rake to enhance uniform drying and prevent over-heating of the top-layer exposed to the sun. Additionally, condensation in the SBD can compromise the quality of grains during drying under humid conditions. In the present study, the Analytical Hierarchy Process (AHP) was used to select an appropriate drying platform, tarpaulin, or elevated drying rack for maize drying in the SBD. Using the AHP, the elevated drying rack was chosen as a suitable platform for drying maize in the SBD. The SBD with the elevated drying racks was used to dry 270 kg of maize from a moisture content of 18.2% to 12.6% (w.w.b) within 6 hours compared to 11 hours for the same quantity of grains dried on the tarpaulin of the SBD to reach an MC of 12.5% (w.w.b). An average drying rate and moisture extraction rate of 0.93%/h and 2.88 kg/h were achieved with the elevated drying rack system compared to 0.52%/h and 1.60 kg/h when drying on the tarpaulin of the SBD. An average temperature of 44.6<span style="white-space:nowrap;">°</span>C recorded in the SBD was 9<span style="white-space:nowrap;">°</span>C more compared to the ambient temperature. The thermal efficiency of the SBD collector was determined as 36.2%. Drying grains with the elevated racks showed advantages of reduced drying time, improved airflow through the drying bed, and prevention of condensation, which occurs when drying on the tarpaulin of the SBD.展开更多
Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a...Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.展开更多
文摘Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under different conditions. As an additive and strengthening agent,
文摘The study evaluates the energy consumption of both wet and dry processes cement manufacturing plant in Nigeria. Enrgy consumption data collected for the period 2003 to 2011 were used to estimate the energy consumption of the crushing, milling, agitation, burning, grinding and bagging operations. The total energy evaluation was based on the three primary energy sources which include electrical, combustion and human. The total estimated energy intensities were 6545 MJ/ton and 4197 MJ/ton for wet and dry processes respectively. The percentage consumption of energy in each operation is 93.68 and 90.34% (burning), 2.11 and 4.33% (milling), 0.43 and 0.67% (crushing), 1.39 and 0% (agitation), 2.12 and 3.90% (grinding), and 0.27 and 0.75% (bagging) of the total energy inputs for the wet and dry processes respectively. Furthermore, the average total energy cost of production showed that wet process is approximately 40% more cost intensive in cement production than the dry process while at the same time it is cost effective to run production on energy through gas powered plant than the national grid.
基金supported by the Key-Area Research and Development Program of Guangdong Province(No.2023B0101200006)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515011926)+1 种基金Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,Guangzhou 510640,China(South China University of Technology)(No.2023B1212060003)State Key Laboratory of Applied Microbiology Southern China(No.SKLAM008-2022)。
文摘The dynamics of the drying process of polymer solutions are important for the development of coatings and films.In the present work,digital holographic microscopy(DHM)was performed to capture the drying dynamics of poly(ethylene oxide)(PEO)droplets using a gold nanoparticle tracer,where the heterogeneous flow field in different regions was illustrated.This demonstrates that the gold nanoparticles at either the center or the edge regions of the droplet exhibit anisotropic kinematic behavior.At early stage,Marangoni backflow causes gold nanoparticles to move towards the edge firstly,and the circles back towards the droplet center after arriving the contact line with a sudden increase in z axis for 10.4μm,indicating the scale of the upward-moving microscopic flow vortices.This phenomenon does not occur in water droplets in the absence of polymers.The gold nanoparticles underwent Brownian-like motion at the center of the PEO droplet or water droplet owing to the low perturbation of the flow field.At the late stage of pinning of the PEO droplets,the motion showed multiple reverses in the direction of the gold nanoparticles,indicating the complexity of the flow field.This study enhances the understanding of the drying dynamics of polymer solution droplets and offers valuable insights into the fabrication of surface materials.
基金funding of the joint Polish-German project SUPILMIX(PR-1173/27)by the German Research Foundation(DFG,Deutsche Forschungsgemeinschaft)+1 种基金funding from the Alexander von Humboldt Foundation.D.L.the German Chemical Industry Fund for the financial support through a Liebig Fellowship.
文摘Supercapacitors are efficient and versatile energy storage devices,offering remarkable power density,fast charge/discharge rates,and exceptional cycle life.As research continues to push the boundaries of their performance,electrode fabrication techniques are critical aspects influencing the overall capabilities of supercapacitors.Herein,we aim to shed light on the advantages offered by dry electrode processing for advanced supercapacitors.Notably,our study explores the performance of these electrodes in three different types of electrolytes:organic,ionic liquids,and quasi-solid states.By examining the impact of dry electrode processing on various electrode and electrolyte systems,we show valuable insights into the versatility and efficacy of this technique.The supercapacitors employing dry electrodes demonstrated significant improvements compared with conventional wet electrodes,with a lifespan extension of+45%in organic,+192%in ionic liquids,and+84%in quasi-solid electrolytes.Moreover,the increased electrode densities achievable through the dry approach directly translate to improved volumetric outputs,enhancing energy storage capacities within compact form factors.Notably,dry electrode-prepared supercapacitors outperformed their wet electrode counterparts,exhibiting a higher energy density of 6.1 Wh cm^(-3)compared with 4.7 Wh cm^(-3)at a high power density of 195Wcm^(-3),marking a substantial 28%energy improvement in the quasi-solid electrolyte.
文摘Biomaterial will shrink during the drying process. The characteristics of shrinkage and rehydration of fresh peas were studied. Drying curves, shrinkage and rehydration curves of peas without seed coats and whole peas were compared. In addition, different volumetric shrinkage coefficients were obtained and discussed. The results show that seed coats resist moisture movement not only from inside to outside but also from outside to inside during different drying conditions. During a seed’s drying process, the drying curve is similar to the shrinkage curve. The higher the heat flux is, the less drying time is needed, and in the meantime, volume would shrink more and more intensively. Dried media will break easily at high heat flux. When we create a drying regime, both drying speed and the quality of dried media should be considered.
基金The National Natural Science Foundation of China (No10471023)
文摘A numerical simulation for a model of wood drying process is considered. The model is given by a couple of nonlinear differential equations. One is a nonlinear parabolic equation and the other one is a nonlinear ordinary equation. A difference scheme is derived by the method of reduction of order. First, a new variable is introduced and the original problem is rewritten into a system of the first-order differential equations. Secondly, a difference scheme is constructed for the later problem. The solvability, stability and convergence of the difference scheme are proved by the energy method. The convergence order of the difference scheme is secondorder both in time and in space. A prior error estimate is put forward. The new variable is put aside to reduce the computational cost. A numerical example testifies the theoretical result.
基金the National Natural Science Foundation of China (Grant No.10702050)the Natural Science Foundation of Tianjin (Grant No.07JCYBJC07500)the Support Plan of Science and Technology of Tianjin (Grant No.07ZCGYSH01700)
文摘A particular porosity method named ＂slot method＂ is implemented in a depth-integrated shallow water flow model （DIVAST） to simulate wetting and drying processes. Discussed is the relationship between the shape factors of the ＂slot＂ and the preset depth used in ＂wetting-drying＂ algorithm. Two typical tests are conducted to examine the performance of the method with the effect of the shape factors of the ＂slot＂ being checked in detail in the first test. Numerical results demonstrate that： 1 ） no additional effort to improve the finite difference scheme is needed to implement ＂slot method＂ in DIVAST, and 2） ＂slot method＂ will simulate wetting and diying processes correctly if the shape factors of the ＂slot＂ being selected properly.
基金“111 Project” Biomedical Textile Materials Science and Technology,China(No.B07024)Natural Science Foundation of Shanghai,China(No.15ZR1401000)the Fundamental Research Funds for the Central Universities,China
文摘A type of antibacterial bacterial cellulose(BC) film was prepared for potential uses as wound dressing.In order to obtain a high antibacterial effect,some forms of BC films,including the wet and dried ones were utilized as the template to in situ synthesize silver nanoparticles(AgNPs).The effects of drying methods including freeze-drying,heat drying and air drying,on the microstructures and physical properties of BC,as well as the silver contents and the antibacterial performances of the BC/AgNPs composites were investigated.It was found that the AgNPs impregnated on the dried BC films were inclined to achieve a faster silver releasing rate than the wet one,which was suitable for acute traumas treatment.
基金the National Key Research and Development Program of China(2017YFB0307900,2019YFC1905903)the National Natural Science Foundation of China(31700507)the Major Project on the Integration of Industry-Education-Research of Fujian Provincial Department of Science and Technology(2018H6003).
文摘Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.
基金Supported by the National Science and Technology Support Program of the Ministry of Science and Technology of the People's Republic of China (No.2011BAI07B05)Shanxi Science and Technology Tackling Fund (No.20100311090,20130313015-2)Department of Health of Shanxi province Tackling Fund (No.200834)
文摘OBJECTIVE： To study the effects of the drying processing in terms operational parameters on the bio- active constituents of six YuanzhJ （Radix Palygalae） samples across China. METHODS： Six Yuanzhi （Radix Palygalae） samples were investigated using thermogravimetry analysis. The heating courses were set in two ways： the temperature-programmed process from room temperature to 150℃ ,and the constant-temperature course at 50℃, 70℃ and 90℃. RESULTS： The peak temperature of six Yuanzhi （Radix Palygalae） samples ranged from 78℃ to 88℃. The mass loss rate of Yuanzhi （Radix Palygalae） alcohol-soluble extract was significantly increased when heated at 90℃. Four types of bioactive ingredients were detected in volatile oils of Yuanzhi （Radix Palygalae） sample from Shanxi province by Gas Chromatography-mass spectrometry analysis. Fourier Transform Infrared Spectroscopy results showed that the drying temperature exerted a great influence on types and amount of ingredients of Yuanzhi （Radix Palygalae）. The kinetic study showed that the constant-temperature drying process of Yuanzhi Radix Palygalae） samples could be well de- scribed by the Page Model, especially for the drying process at 50~C, in which R2 and SD values were more than 0.98 and less than 0.04, respectively.The drying constant k of three Yuanzhi （Radix Palygalae） samples from Shanxi, Gansu and Shaanxi provinces in China was corresponding to the Arrhenius equation, and their activation energies were 28.07, 2.5.38 and 21.48 kJ/mol, respectively. CONCLUSION： The drying process of Yuanzhi （Radix Palygalae） was very important for bioactive ingredients improvement in Yuanzhi （Radix Palygalae）. Temperature was a thermodynamic property significantly affecting the process.
基金National Natural Science Foundation of China(31570331,31170307)National Key Research and Development Program of China(2017YFC1700702)Project of Beijing University of Chinese Medicine(2019-JYB-XS-087).
文摘[Objectives]To determine the drying process of different functional rhubarbs.[Methods]The contents of tannins,bianthrone,free anthraquinones and combined anthraquinones in medicinal rhubarb were determined by HPLC.The results were analyzed by two-way analysis of variance.[Results]Under different drying conditions,the contents of tannins,bianthrone,free anthraquinones and combined anthraquinones in medicinal rhubarb were significantly different.Taking the tannins content as the index,the optimum drying condition of the rhizome is 1 cm thick,dried at 60℃,the root is cut 1 cm thick,and dried at 30℃;the bianthrone content is used as an indicator,the rhizome is optimally dried.The condition is to cut 1 cm thick,dry at 60℃,the root is cut to 5 cm thick,and dried at 40℃;the free anthraquinones content is used as an index,and the optimum drying condition of the rhizome is 3 cm thick and dried at 50℃.The root is cut to a thickness of 3 cm and dried at 30℃.The combine anthraquinones content is used as an indicator.The optimum drying conditions for the rhizome are 5 cm thick,dried at 40℃,and the root is cut to 5 cm thick and dried at 70℃.[Conclusions]Different functional components of rhubarb have different directional processing methods.The drying process can reduce the drying temperature or increase the thickness of the slice,and the directional processing of the diarrhea-type rhubarb can be processed.The drying process can be carried out by increasing the drying temperature or reducing the thickness of the slice directed processing of heat-clearing and purging-fire rhubarb.
基金Funded by the National High Technology Research and Development Program(863 Program)(No.2013AA050905),China Academy of Engineering Physics,Mianyang,China
文摘Carbon aerogels were synthesized via ambient pressure drying process using resorcinolformaldehyde as precursor and P123 to strengthen their skeletons. CO2 activation technology was implemented to improve surface areas and adjust pore size distribution. The synthesis process was optimized, and the morphology, structure, adsorption properties and electrochemical behavior of different samples were characterized. The CO2-activated samples achieved a high specific capacitance of 129.2 F/g in 6 M KOH electrolytes at the current density of 1 m A/cm^2 within the voltage range of 0-0.8 V. The optimized activation temperature and duration were determined to be 950 ℃ and 4 h, respectively.
文摘This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.
文摘Drying of the banana in the hot water has a negative impact on the quality of the product and drying effect. The purposes of this study are increasing the drying rate, using the relatively low temperature to improve the quality (40℃, 50℃ and 60℃) and investigate the use of electromagnetic waves to increase the drying speed. Therefore, experiments are performed using 5 kHz,10 kHz and 15 kHz low frequency electromagnetic waves in the air velocity values of 0.5 m/s, 1 m/s, 1.5 m/s and 2 m/s and 40℃, 50℃, 60℃ centigrade degrees of air blast in a special compartment. Mathematical model of the drying process has been created as using the electrical circuits methods and experimental results. As a result, a simple equation describing the drying process has been obtained. Nonlinear expression of the diffusion coefficient for a different situation in this equation has been identified for the first time. The obtained theoretical results and experimental results have been provided a good agreement. This study is considered to be useful for all studies in the drying area.
文摘A coupling model between the canopy layer(CL) and atmospheric boundary layer (ABL) for the study of dry deposition velocity is developed. The model consists of six parts: chemical species conservation equation including absorptive factor; the species uptake action including detailed vertical variation of absorptive element in CL; momentum exchange in CL which is represented by a first-order closure momentum equation with an additional larger-scale diffusive term; momentum exchange in ABL which is described by a complete set of the ABL turbulent statistic parameters; absorptivity (or solubility or reflection) at the surface including effects of the physical and chemical characters of the species, land type, seasonal and diurnal variations of the meteorological variables; and deposition velocity derived by distributions of the species with height in CL. Variational rules of the concentration and deposition velocity with both height and time are simulated with the model for both corn and forest canopies. Results predicted with the bulk deposition velocity derived in the paper consist well with experimental data.
文摘In this study the effect of initial parameters such as inlet gas temperature, initial particles temperature and gas velocity on temperature changes of solid particles and outlet gas temperature in a fluidized bed dryer was studied. For testing, an experimental setup was established. With combination of air and Colza seeds belonging to D groups of the Geldart classification (Geldart, 1986) fluidization regime was carried out. With five test series with maintaining the inlet gas temperature, solid particle temperature and outlet gas temperature during time were carefully measured. To analyze these data by using regression analysis to predict solid particle and outlet gas temperature, 2 correlations on initial pa-rameters were presented. The result has shown that temperature gradients in the beginning of fluidization, is very high and therefore the exponential functions in the regression model is used to predict the temperature changes.
文摘Drying processing of Habanero chili was improved, through solar energy usage. Habanero chili is a notable seasonal product being drying such important for Mexican producers; this process is expensive and wasteful of energy. A feasibility analysis was developed, to determine the market tendency and the optimal drying conditions for redesign Habanero chili drying process, through a hybrid solar-electric energy usage. The new drying process would be held in two stages： （a） an open solar dryer was used; （b） an existing pilot fluidized bed dryer was adapted with a low temperature solar collector for air heating. Habanero chili was dehydrated from 90% to 5% moisture in 10.3 h, with good quality product, available for commercialization. A reduction in the average drying time of 50% was obtained, also, in the energy usage of 77% in the fluidized bed dryer, with an energy saving of 0.52 kg of natural gas per kg of fresh Habanero chili. An innovative sustainable efficient drying process was developed, and will be strategic to expand the market for Habanero chili with low energy cost.
文摘The aim of this paper is to select the best location for the construction of a dry port in Niger which is a land locked country (LLC). Niger is located in the Sahel and has a land area of 1,267,000 square kilometers [1], with the closest port being port of Cotonou in Benin. The transport corridor from Niamey to Cotonou is approximately 1036 km long [2]. It is estimated that this corridor carries about 40 percent of Niger’s overseas trade traffic [3]. In this work, the Analytic Network Process (ANP) model is used to determine the optimal location of the dry port, among three major cities: Niamey (capital city), Dosso and Gaya. From the application of this selection model, Dosso was selected as the best location for the location of the dry port, while Gaya and Niamey were placed second and third respectively. The results obtained in this work strongly confirm the decision of the government of Niger to construct a dry port in Dosso, a project that commenced in 2010 and is still in progress.
文摘The solar bubble dryer (SBD) is a convenient and better option to traditional open sun drying commonly practiced by smallholder farmers in Ghana and other developing countries. However, to operate the SBD, one is faced with the challenge of frequent mixing of grains using a rake to enhance uniform drying and prevent over-heating of the top-layer exposed to the sun. Additionally, condensation in the SBD can compromise the quality of grains during drying under humid conditions. In the present study, the Analytical Hierarchy Process (AHP) was used to select an appropriate drying platform, tarpaulin, or elevated drying rack for maize drying in the SBD. Using the AHP, the elevated drying rack was chosen as a suitable platform for drying maize in the SBD. The SBD with the elevated drying racks was used to dry 270 kg of maize from a moisture content of 18.2% to 12.6% (w.w.b) within 6 hours compared to 11 hours for the same quantity of grains dried on the tarpaulin of the SBD to reach an MC of 12.5% (w.w.b). An average drying rate and moisture extraction rate of 0.93%/h and 2.88 kg/h were achieved with the elevated drying rack system compared to 0.52%/h and 1.60 kg/h when drying on the tarpaulin of the SBD. An average temperature of 44.6<span style="white-space:nowrap;">°</span>C recorded in the SBD was 9<span style="white-space:nowrap;">°</span>C more compared to the ambient temperature. The thermal efficiency of the SBD collector was determined as 36.2%. Drying grains with the elevated racks showed advantages of reduced drying time, improved airflow through the drying bed, and prevention of condensation, which occurs when drying on the tarpaulin of the SBD.
文摘Pulverized fly ash (PFA) is produced about 500 billions tons every year in the world in a result of coals combustion. Most of the fly ash collected in power plants is disposed by deposition in landfills, situated as a rule near big cities with well developed infrastructure and high cost of land. Moreover, the pollution of environmental by fine solid wastes is inevitable and takes place in area of residing of a basic part of the population. The only solution is a complex processing of fine wastes with a production of value added materials. New conception of complex processing of PFA is proposed on the base of facilities of Electro-mass-classifier (EMC) and other techniques. The characterization of separated fractions was carried out by SEM and optic microscopy, XRD, laser diffraction, M?ssbauer spectroscopy and other methods. A fine fraction of glass microspheres presents the main interest as filler in various materials.
