The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat sto...The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.展开更多
This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues o...This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources.The proposed active hybrid solar dryer features a drying cabinet,two Direct Current(DC)fans for forced convection,and a resistive heating element powered by a 180 W solar PV panel.An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance,poor weather conditions,or nighttime.Tomatoes,a delicate and in-demand crop,were selected for experimentation due to their high perishability.Three experiments were conducted on the same prototype:natural convection direct solar dryer(NCDSD),forced convection direct solar dryer(FCDSD),and forced convection hybrid solar dryer(FCHSD).Each experiment began with 0.2 kg of tomatoes at 94%moisture content,achieving significant reductions:28.57%with NCDSD,16.667%with FCDSD,and 16.667%with FCHSD.The observed drying rates varied:1.161 kg/h for NCDSD,2.062 kg/h for FCDSD,and 2.8642 kg/h for FCHSD.This study presents a comparative analysis of efficiency,drying rate,and cost-effectiveness,alongside the system’s economic and environmental feasibility.展开更多
The design and development of solar dryers are crucial in regions with abundant solar energy,such as Bhopal,India,where seasonal variations significantly impact the efficiency of drying processes.The paper is focused ...The design and development of solar dryers are crucial in regions with abundant solar energy,such as Bhopal,India,where seasonal variations significantly impact the efficiency of drying processes.The paper is focused on employing a comprehensive mathematical model to predict the dryer’s performance in drying the materials such as banana slices.To enhance this model,Hyper Tuned Swarm Optimization with Gradient Tree(HT_SOGT)was utilized to accurately predict and determine the optimal size of the dryer dimensions considering various mathematical calculations for material drying.The predictive model considered the influence of seasonal fluctuations,ensuring an efficient drying process with an objective function to optimize the drying time of an average of 7 hrs throughout the year.Across all recorded ambient temperatures(ranging from 16.985○C to 31.4○C),the outlet temperature of the solar dryer is consistently higher,ranging from 39.085○C to 66.2○C.The results show that the optimized dryer design,based on HT_SOGT modelling,significantly improves drying efficiency of the materials across varying conditions,making it suitable for sustainable applications in agriculture and food processing industries in the Bhopal region.展开更多
The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise character...The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise characteristics of a commercial high-speed hair dryer through Computational Fluid Dynamics(CFD)analysis.The velocity field,streamline patterns,and vector distribution within the primary flow path and internal cavity were systematically examined.Results indicate that strong interactions between the wake flow generated by the guide vanes and the straight baffle in the rear flow path induce vortex structures near the outlet,which are primarily responsible for highfrequency noise.To address this,the guide vanes and rear flow path geometry were redesigned and optimized for improved acoustic and aerodynamic performance.Underrated operating conditions(28 V,20,000 rpm),the optimized configuration achieves a noise reduction of more than 2.2 dB while increasing outlet wind speed by over 9%.Moreover,the noise suppression effect becomes more pronounced at lower rotational speeds.展开更多
A multi functional wood dehumidification dryer has been developed recently. The dryer can carry out air dehumidification by using only one refrigeration system, in which heat supplying and moisture air are exhausted ...A multi functional wood dehumidification dryer has been developed recently. The dryer can carry out air dehumidification by using only one refrigeration system, in which heat supplying and moisture air are exhausted by changing the position of several air dampers. In this paper, the work principles and characteristics of the dehumidification dryer are introduced, and the testing results about the thermal engineering performance of the dehumidification dryer, as well as the experiment results of drying several species of lumbers are expounded.展开更多
Based on the demand of sintering/pelleting flue gas ultra-low emission,a semi-dry method using a spray dryer absorber (SDA) combined with O3 oxidation was proposed for simultaneous removal of SO2 and NO.Effects of O3 ...Based on the demand of sintering/pelleting flue gas ultra-low emission,a semi-dry method using a spray dryer absorber (SDA) combined with O3 oxidation was proposed for simultaneous removal of SO2 and NO.Effects of O3 injection site,O3/NO molar ratio,and spray tower temperature on the removal efficiencies were investigated.It was revealed that both desulfurization and denitrification efficiencies could reach to 85%under the conditions of setting O3 injection site inside of tower,O3/NO molar ratio 1.8,spray tower temperature 85°C,Ca/(S+2N) molar ratio 2.5 and slurry flow rate 300 m L/hr.CaSO3/Ca(OH)2 mixture slurry was used as absorbent to simulate operating conditions in iron and steel industry.The result shows that the addition of CaSO3 weakens both removal efficiencies.In addition,the reaction mechanism of simultaneous removal of SO2 and NO using SDA combined with O3 oxidation was proposed.展开更多
Background: Forest management decisions are based on expectations of future developments. For sound decisions it is essential to accurately predict the expected values in future developments and to account for their i...Background: Forest management decisions are based on expectations of future developments. For sound decisions it is essential to accurately predict the expected values in future developments and to account for their inherent uncertainty,for example the impact of climate change on forests. Changing climatic conditions affect forest productivity and alter the risk profile of forests and forest enterprises. Intensifying drought stress is seen as one major risk factor threatening forest management in the north German lowlands. Drought stress reduces tree growth and vitality and might even trigger mortality. But so far, it is not possible to quantify effects of a persistent dryer climate on forest productivity at a level suitable for forest management.Methods: We apply a well-established single-tree forest growth simulator to quantify the effect of persistent dryer climates on future forest productivity. We analyse the growth of Scots pine(Pinus sylvestris L.), European beech(Fagus sylvatico L.) and oak(Quercus robur L. and Quercus petraea(Matt.) Liebl.) in two forest regions in the north German lowlands for a time interval of 60 years until 2070. The growth response under three different climate projections is compared to a baseline scenario.Results: The results show clear differences in volume increment to persistent dryer climates between tree species. The findings exhibit regional differences and temporal trends. While mean annual increment at biological rotation age of Scots pine and oak predominantly benefits from the projected climate conditions until 2070, beech might suffer losses of up to 3 m^3·ha^(-1)yr^(-1) depending on climate scenario and region. However, in the projection period2051 to 2070 the uncertainty ranges comprise positive as well as negative climatic effects for all species.Conclusions: The projected changes in forest growth serve as quantitative contributions to provide decision support in the evaluation of, for example, species future site suitability and timber supply assessments. The analysis of productivity changes under persistent dryer climate complements the drought vulnerability assessment which is applied in practical forestry in northwestern Germany today. The projected species' productivity has strong implications for forest management and the inherent uncertainty needs to be accounted for.展开更多
文摘The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.
基金supported by the Ignite National Technology fund,under National Grassroots Initiatives Program of ICT R&D(NIGRI),Project ID.NGIRI-2024-23901 of 2024.
文摘This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources.The proposed active hybrid solar dryer features a drying cabinet,two Direct Current(DC)fans for forced convection,and a resistive heating element powered by a 180 W solar PV panel.An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance,poor weather conditions,or nighttime.Tomatoes,a delicate and in-demand crop,were selected for experimentation due to their high perishability.Three experiments were conducted on the same prototype:natural convection direct solar dryer(NCDSD),forced convection direct solar dryer(FCDSD),and forced convection hybrid solar dryer(FCHSD).Each experiment began with 0.2 kg of tomatoes at 94%moisture content,achieving significant reductions:28.57%with NCDSD,16.667%with FCDSD,and 16.667%with FCHSD.The observed drying rates varied:1.161 kg/h for NCDSD,2.062 kg/h for FCDSD,and 2.8642 kg/h for FCHSD.This study presents a comparative analysis of efficiency,drying rate,and cost-effectiveness,alongside the system’s economic and environmental feasibility.
文摘The design and development of solar dryers are crucial in regions with abundant solar energy,such as Bhopal,India,where seasonal variations significantly impact the efficiency of drying processes.The paper is focused on employing a comprehensive mathematical model to predict the dryer’s performance in drying the materials such as banana slices.To enhance this model,Hyper Tuned Swarm Optimization with Gradient Tree(HT_SOGT)was utilized to accurately predict and determine the optimal size of the dryer dimensions considering various mathematical calculations for material drying.The predictive model considered the influence of seasonal fluctuations,ensuring an efficient drying process with an objective function to optimize the drying time of an average of 7 hrs throughout the year.Across all recorded ambient temperatures(ranging from 16.985○C to 31.4○C),the outlet temperature of the solar dryer is consistently higher,ranging from 39.085○C to 66.2○C.The results show that the optimized dryer design,based on HT_SOGT modelling,significantly improves drying efficiency of the materials across varying conditions,making it suitable for sustainable applications in agriculture and food processing industries in the Bhopal region.
基金supported by Research Project of Zhuhai City Polytechnic(Grant No.2024KYBS06)Education Research Project of Zhuhai City Polytechnic(Grant No.JY20250404).
文摘The noise generated by high-speed hair dryers significantly affects user experience,with aerodynamic design playing a crucial role in controlling sound emissions.This study investigates the aerodynamic noise characteristics of a commercial high-speed hair dryer through Computational Fluid Dynamics(CFD)analysis.The velocity field,streamline patterns,and vector distribution within the primary flow path and internal cavity were systematically examined.Results indicate that strong interactions between the wake flow generated by the guide vanes and the straight baffle in the rear flow path induce vortex structures near the outlet,which are primarily responsible for highfrequency noise.To address this,the guide vanes and rear flow path geometry were redesigned and optimized for improved acoustic and aerodynamic performance.Underrated operating conditions(28 V,20,000 rpm),the optimized configuration achieves a noise reduction of more than 2.2 dB while increasing outlet wind speed by over 9%.Moreover,the noise suppression effect becomes more pronounced at lower rotational speeds.
文摘A multi functional wood dehumidification dryer has been developed recently. The dryer can carry out air dehumidification by using only one refrigeration system, in which heat supplying and moisture air are exhausted by changing the position of several air dampers. In this paper, the work principles and characteristics of the dehumidification dryer are introduced, and the testing results about the thermal engineering performance of the dehumidification dryer, as well as the experiment results of drying several species of lumbers are expounded.
基金supported by the Nationals Key Research and Development Program of China (No.2017YFC0210600)the National Natural Science Foundation of China (No.51978644)。
文摘Based on the demand of sintering/pelleting flue gas ultra-low emission,a semi-dry method using a spray dryer absorber (SDA) combined with O3 oxidation was proposed for simultaneous removal of SO2 and NO.Effects of O3 injection site,O3/NO molar ratio,and spray tower temperature on the removal efficiencies were investigated.It was revealed that both desulfurization and denitrification efficiencies could reach to 85%under the conditions of setting O3 injection site inside of tower,O3/NO molar ratio 1.8,spray tower temperature 85°C,Ca/(S+2N) molar ratio 2.5 and slurry flow rate 300 m L/hr.CaSO3/Ca(OH)2 mixture slurry was used as absorbent to simulate operating conditions in iron and steel industry.The result shows that the addition of CaSO3 weakens both removal efficiencies.In addition,the reaction mechanism of simultaneous removal of SO2 and NO using SDA combined with O3 oxidation was proposed.
基金funded by the German Federal Ministry of Fducation and Research under research grant 033L029H and is part of the interdisciplinary research project"Sustainable land-use management in the North German lowlands"
文摘Background: Forest management decisions are based on expectations of future developments. For sound decisions it is essential to accurately predict the expected values in future developments and to account for their inherent uncertainty,for example the impact of climate change on forests. Changing climatic conditions affect forest productivity and alter the risk profile of forests and forest enterprises. Intensifying drought stress is seen as one major risk factor threatening forest management in the north German lowlands. Drought stress reduces tree growth and vitality and might even trigger mortality. But so far, it is not possible to quantify effects of a persistent dryer climate on forest productivity at a level suitable for forest management.Methods: We apply a well-established single-tree forest growth simulator to quantify the effect of persistent dryer climates on future forest productivity. We analyse the growth of Scots pine(Pinus sylvestris L.), European beech(Fagus sylvatico L.) and oak(Quercus robur L. and Quercus petraea(Matt.) Liebl.) in two forest regions in the north German lowlands for a time interval of 60 years until 2070. The growth response under three different climate projections is compared to a baseline scenario.Results: The results show clear differences in volume increment to persistent dryer climates between tree species. The findings exhibit regional differences and temporal trends. While mean annual increment at biological rotation age of Scots pine and oak predominantly benefits from the projected climate conditions until 2070, beech might suffer losses of up to 3 m^3·ha^(-1)yr^(-1) depending on climate scenario and region. However, in the projection period2051 to 2070 the uncertainty ranges comprise positive as well as negative climatic effects for all species.Conclusions: The projected changes in forest growth serve as quantitative contributions to provide decision support in the evaluation of, for example, species future site suitability and timber supply assessments. The analysis of productivity changes under persistent dryer climate complements the drought vulnerability assessment which is applied in practical forestry in northwestern Germany today. The projected species' productivity has strong implications for forest management and the inherent uncertainty needs to be accounted for.
