The conservation of cola nuts (Cola nitida) poses a real problem in Côte d’Ivoire because of the post-harvest losses. The objective of this study was to evaluate the impact of post-harvest technologies on o...The conservation of cola nuts (Cola nitida) poses a real problem in Côte d’Ivoire because of the post-harvest losses. The objective of this study was to evaluate the impact of post-harvest technologies on organoleptic and physical properties of cola nut during storage. A biopesticide, glucose syrup and biopesticide + glucose syrup were applied to fresh cola nuts before conditioning and kept at 28°C for 6 weeks. Physicochemical and sensory analyses were performed to check the quality of the nuts during storage. The results showed that the biopesticide keep cola nuts better than the others methods with only 11.66% ± 3.04% and 13.66% ± 3.95% of loss rates for white and red cola nuts respectively. Cola nuts treated with bio-pesticide retain significantly their freshness with 62.00% ± 1.15% of moisture for white nuts and 64.00% ± 2.00% of moisture for red nuts compared to those treated with glucose syrup and bio-pesticide + glucose syrup (56.66% ± 1.15%). Cola nuts treated with biopesticide have a better acceptability compared to those subjected to others treatments. The use of biopesticide for the storage of cola nuts minimizes the losses and maintains the quality whatever the type of cola.展开更多
In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage system.In order...In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage system.In order to improve the hydrogen utilization rate of hydrogen storage system in the process of participating in the power grid operation,and speed up the process of electric-hydrogen-electricity conversion.This article provides a detailed introduction to the mathematical and electrical models of various components of the hydrogen storage unit,and also establishes a charging and discharging efficiency model that considers the temperature and internal gas partial pressure of the hydrogen storage unit.These models are of great significance for studying and optimizing gas storage technology.Through these models,the performance of gas storage units can be better understood and improved.These studies are very helpful for improving energy storage efficiency and sustainable development.The factors affecting the charge-discharge efficiency of hydrogen storage units are analyzed.By integrating the models of each unit and considering the capacity degradation of the hydrogen storage system,we can construct an efficiency model for a large hydrogen storage system and power conversion system.In addition,the simulation models of the hydrogen production system and hydrogen consumption system were established in MATLAB/Simulink.The accuracy and effectiveness of the simulation model were proved by comparing the output voltage variation curve of the simulation with the polarization curve of the typical hydrogen production system and hydrogen consumption system.The results show that the charge-discharge efficiency of the hydrogen storage unit increases with the increase of operating temperature,and H2 and O2 partial voltage have little influence on the charge-discharge efficiency.In the process of power conversion system converter rectification operation,its efficiency decreases with the increase of temperature,while in the process of inverter operation,power conversion system efficiency increases with the increase of temperature.Combined with the efficiency of each hydrogen storage unit and power conversion system converter,the upper limit of the capacity loss of different hydrogen storage units was set.The optimal charge-discharge efficiency of the hydrogen storage system was obtained by using the Cplex solver at 36.46%and 66.34%.展开更多
Power quality improvements help guide and solve the problems of inefficient energy production and unstable power output in wind power systems.The purpose of this paper is mainly to explore the influence of different e...Power quality improvements help guide and solve the problems of inefficient energy production and unstable power output in wind power systems.The purpose of this paper is mainly to explore the influence of different energy storage batteries on various power quality indicators by adding different energy storage devices to the simulated wind power system,and to explore the correlation between systementropy generation and various indicators,so as to provide a theoretical basis for directly improving power quality by reducing loss.A steady-state experiment was performed by replacing the wind wheel with an electric motor,and the output power qualities of the wind power systemwith andwithout energy storagewere compared and analyzed.Moreover,the improvement effect of different energy storage devices on various indicatorswas obtained.Then,based on the entropy theory,the loss of the internal components of the wind power system generator is simulated and explored by Ansys software.Through the analysis of power quality evaluation indicators,such as current harmonic distortion rate,frequency deviation rate,and voltage fluctuation,the correlation between entropy production and each evaluation indicator was explored to investigate effective methods to improve power quality by reducing entropy production.The results showed that the current harmonic distortion rate,voltage fluctuation,voltage deviation,and system entropy production are positively correlated in the tests and that the power factor is negatively correlated with system entropy production.In the frequency range,the frequency deviationwas not significantly correlated with the systementropy production.展开更多
Hazelnuts are an economically important nut which is consumed world-wide.It is prone to infection by Aspergillus flavus and contamination with aflatoxins.Taking Tukey’s hazelnuts as a research object,the objective of...Hazelnuts are an economically important nut which is consumed world-wide.It is prone to infection by Aspergillus flavus and contamination with aflatoxins.Taking Tukey’s hazelnuts as a research object,the objective of this study were to(a)quantify respiration rates and(b)dry matter losses(DMLs)and(c)aflatoxin B_(1)(AFB_(1))contamination of naturally stored shelled hazelnuts at different temperatures and water availabilities.Subsequently,shelled hazelnuts were inoculated with additional A.flavus inoculum prior to storage to examine effects on dry matter losses and on AFB_(1) contamination.Maximum respiration of hazelnuts and associated mycoflora was under wetter conditions of 0.90~0.95 water activity(aw=12.5%~18%moisture content).This resulted in between approx.10%DML at 25 and 30℃after 5 days storage.Inoculation and storage of shelled hazelnuts+A.flavus inoculum resulted in similar patterns of respiration with optimal levels at 25~30℃and>0.90 aw.Indeed,AFB_(1) contamination was highest at the maximum water levels tested of 0.90 aw.Indeed the contamination level exceeded the legislative limits set by the EU for AFB_(1) contamination of these nuts.Correlation between DMLs and all the AFB_(1) data in both sets of studies showed that very small changes in DML due to poor drying or storage of≥0.6%resulted in AFB_(1) contamination levels exceeding the EU legislative limits.Thus,efficient drying and safe monitored storage is necessary to minimise the risk of AFB_(1) contamination in this economically important commodity and to avoid exposure of consumers to such toxins.展开更多
Moran considered a dam whose inflow in a given interval of time is a continuous random variable. He then developed integral equations for the probabilities of emptiness and overflow. These equations are difficult to s...Moran considered a dam whose inflow in a given interval of time is a continuous random variable. He then developed integral equations for the probabilities of emptiness and overflow. These equations are difficult to solve numerically;thus, approximations have been proposed that discretize the input. In this paper, extensions are considered for storage systems with different assumptions for storage losses. We also develop discrete approximations for the probabilities of emptiness and overflow.展开更多
High postharvest losses in developing countries negate the efforts geared towards improving food security. Poor produce quality including high prevalence of mycotoxin contamination is another significant problem. Appr...High postharvest losses in developing countries negate the efforts geared towards improving food security. Poor produce quality including high prevalence of mycotoxin contamination is another significant problem. Appropriate postharvest handling and processing provide opportunities to reduce postharvest losses and improve food safety. This study was aimed at establishing the postharvest handling practices and estimating qualitative and quantitative postharvest losses for maize, millet, sorghum, beans, groundnuts, cassava, and sweet potatoes among farmers in 3 districts (Kamuli, Apac and Nakasongola) in Uganda, representing different agro-ecological zones. The study was done in late August 2014 after the first season harvests (June-August). Farmer interviews, focus group discussions and key informant interviews were used to collect data on postharvest loss estimates and postharvest handling practices. Samples of the different foods were collected and analyzed for physical quality characteristics, mould count and aflatoxin contamination using standard laboratory procedures. The results show predominance of rudimentary and inappropriate postharvest handling methods. Postharvest loss estimates were generally high, with values of 41%, 33%, 33%, 26%, 31%, 22%, 17% and 19% for maize, millet, sorghum, beans, groundnuts, cowpea, sweet potatoes and cassava respectively. The highest loss for all the crops was recorded at storage. Prevalence of aflatoxin contamination was 44%, 91%, 55%, 36%, 35% and 60% for maize, sorghum, groundnuts, millet, sweet potatoes and cassava respectively. Sorghum, maize and groundnuts were found to have the highest aflatoxin contamination levels. Chi-square test (p = 0.024, odds ratio = 5) showed that grain dried on bare ground had higher aflatoxin levels than that dried on a covered surface. The findings of this study reveal a serious need for postharvest interventions as a strategy to address food security.展开更多
Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage ...Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.展开更多
In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the ir...In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the iron loss of SRS/G is mainly studied to reduce the motor loss and improve the power generation efficiency.Then,the energy storage of hybrid EVs can be effectively improved.Secondly,a magnetic flux density(MFD)waveforms solution method is proposed to solve the difficulty in calculating the iron loss of the SRS/G.Compared with the commonly used finite element method,the proposed solution method has the advantages of simple,fast and small computational amount.Meanwhile,considering the different operating conditions of SRS/G,the iron loss models for both the time-domain and frequency-domain are established.In addition,the calculation formula of the variable coefficient Bertotti three-term loss separation is improved.As the hysteresis loss coefficient,the Steinmetz coefficient and the stray loss coefficient are respectively fitted by the Fourier fitting method.This method is also applied to solve the iron loss of SRS/G.Finally,through an experimental verification,it is indicated that the development of proposed method has high accuracy.展开更多
The effects of treatment of chlorine dioxide （C1Oz） gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20,...The effects of treatment of chlorine dioxide （C1Oz） gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L^-1 ClO2 gas at 10±0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L^-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly （P〈0.05） inhibited by 20 and 50 mg L^-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L^-1 ClO2 treatments （P〉0.05）. Except for 50 mg L^-1 ClO2, malondialdenyde （MDA） contents in the peppers treated with 5, 10, or 20 mg L^-1 ClO2 were not significantly （P〉0.05） different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1ClO2, but promoted by 10, 20, or 50 mg L^-1 ClO2. The vitamin C content, titratable acidity, and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage. The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.展开更多
Investigating the immobilization of CO2,previous basalt-water-CO2 interaction studies revealed the formation of carbonates over a short period,but with the extensive formation of secondary silicates(SS).The mechanisms...Investigating the immobilization of CO2,previous basalt-water-CO2 interaction studies revealed the formation of carbonates over a short period,but with the extensive formation of secondary silicates(SS).The mechanisms involved in these processes remain unresolved,so the present study was undertaken to understand secondary mineral formation mechanisms.XRPD and Rietveld refinement data for neo-formed minerals show a drastic decrease in the Ca-O bond length,with the calcite structure degenerating after 80 h(hours).However,SEM images and EDS data revealed that a longer interaction time resulted in the formation of chlorite and smectite,adjacent to basalt grains which prevent basaltwater-CO2 interaction to form carbonates,thus restricting carbonate formation.As a result of this,the CO2 mineralization rate is initially high(till 80 h),but it later reduces drastically.It is evident that,for such temperature-controlled transformations,low temperature is conducive to minimizing SS surface coating at the time of mineral carbonation.展开更多
In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and t...In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and technology. The losses of farmer＇s grain storage could reach nearly 20 million tons every year. In this paper, the current situation and development of grain storage technology and facility for Chinese farmers were presented. And a series of policy and research work for reducing the losses of farms＇ grain storage was introduced. The large scale farmers are now developing quickly in China, the new storage warehouse and mechanized facility should be developed adaptively. So, the new storage technology and policy to meet the need of large scale farmers were also introduced in this paper.展开更多
There are many reservoirs in China,and serious reservoir sedimentation affects reservoir function and reservoir safety.It is of great significance for restoring the reservoir capacity,improving the efficiency of the r...There are many reservoirs in China,and serious reservoir sedimentation affects reservoir function and reservoir safety.It is of great significance for restoring the reservoir capacity,improving the efficiency of the reservoir and prolonging the service life of the reservoir to carry out the research on reservoir sedimentation control and storage capacity recovery technology,in the case of fewer and fewer good dam sites suitable for the construction of the reservoir and the increasing accumulation of reservoir sedimentation.In this paper,influence factor of the storage loss,sedimentation control and reservoir capacity recovery technology in China are briefly reviewed.It is necessary to carry out research work on reservoir sedimentation investigation and reservoir siltation mechanism and control measures.展开更多
Agricultural control systems are characterized by complexity and uncertainly. A skilled grower can deal well with crops based on his own intuition and experience. In this study, an intelligent optimization technique m...Agricultural control systems are characterized by complexity and uncertainly. A skilled grower can deal well with crops based on his own intuition and experience. In this study, an intelligent optimization technique mimicking the simple thinking process of a skilled grower is proposed and then applied to dynamic optimization of temperature that minimizes the water loss in fruit during storage. It is supposed that the simple thinking process of a skilled grower consists of two steps: 1) “learning and modeling” through experience and 2) “selection and decision of an optimal value” through simulation of a mental model built in his brain by the learning. An intelligent control technique proposed here consists of a decision system and a feedback control system. In the decision system, the dynamic change in the rate of water loss as affected by temperature was first identified and modeled using neural networks (“learning and modeling”), and then the optimal value (l-step set points) of temperature that minimized the rate of water loss was searched for through simulation of the identified neural-network model using genetic algorithms (“selection and decision”). The control process for 8 days was divided into 8steps. Two types of optimal values, a single heat stress application, such as 40℃, 15℃, 15℃, 15℃, 15℃, 15℃, 15℃and 15℃, and a double heat stress application, such as 40℃, 15℃, 40℃, 15℃, 15℃, 15℃, 15℃and 15℃, were obtained under the range of 15℃￡T￡40℃. These results suggest that application of heat stress to fruit is effective in maintaining freshness of fruit during storage.展开更多
文摘The conservation of cola nuts (Cola nitida) poses a real problem in Côte d’Ivoire because of the post-harvest losses. The objective of this study was to evaluate the impact of post-harvest technologies on organoleptic and physical properties of cola nut during storage. A biopesticide, glucose syrup and biopesticide + glucose syrup were applied to fresh cola nuts before conditioning and kept at 28°C for 6 weeks. Physicochemical and sensory analyses were performed to check the quality of the nuts during storage. The results showed that the biopesticide keep cola nuts better than the others methods with only 11.66% ± 3.04% and 13.66% ± 3.95% of loss rates for white and red cola nuts respectively. Cola nuts treated with bio-pesticide retain significantly their freshness with 62.00% ± 1.15% of moisture for white nuts and 64.00% ± 2.00% of moisture for red nuts compared to those treated with glucose syrup and bio-pesticide + glucose syrup (56.66% ± 1.15%). Cola nuts treated with biopesticide have a better acceptability compared to those subjected to others treatments. The use of biopesticide for the storage of cola nuts minimizes the losses and maintains the quality whatever the type of cola.
基金supported by the Jilin Province Higher Education TeachingReform Research Project Funding(Contract No.2020285O73B005E).
文摘In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage system.In order to improve the hydrogen utilization rate of hydrogen storage system in the process of participating in the power grid operation,and speed up the process of electric-hydrogen-electricity conversion.This article provides a detailed introduction to the mathematical and electrical models of various components of the hydrogen storage unit,and also establishes a charging and discharging efficiency model that considers the temperature and internal gas partial pressure of the hydrogen storage unit.These models are of great significance for studying and optimizing gas storage technology.Through these models,the performance of gas storage units can be better understood and improved.These studies are very helpful for improving energy storage efficiency and sustainable development.The factors affecting the charge-discharge efficiency of hydrogen storage units are analyzed.By integrating the models of each unit and considering the capacity degradation of the hydrogen storage system,we can construct an efficiency model for a large hydrogen storage system and power conversion system.In addition,the simulation models of the hydrogen production system and hydrogen consumption system were established in MATLAB/Simulink.The accuracy and effectiveness of the simulation model were proved by comparing the output voltage variation curve of the simulation with the polarization curve of the typical hydrogen production system and hydrogen consumption system.The results show that the charge-discharge efficiency of the hydrogen storage unit increases with the increase of operating temperature,and H2 and O2 partial voltage have little influence on the charge-discharge efficiency.In the process of power conversion system converter rectification operation,its efficiency decreases with the increase of temperature,while in the process of inverter operation,power conversion system efficiency increases with the increase of temperature.Combined with the efficiency of each hydrogen storage unit and power conversion system converter,the upper limit of the capacity loss of different hydrogen storage units was set.The optimal charge-discharge efficiency of the hydrogen storage system was obtained by using the Cplex solver at 36.46%and 66.34%.
基金Supported by the National Natural Science Foundation of China(No.51966013)Inner Mongolia Natural Science Foundation Jieqing Project(No.2023JQ04)+1 种基金the National Natural Science Foundation of China(No.51966018)the Natural Science Foundation of Inner Mongolia Autonomous Region(No.STZC202230).
文摘Power quality improvements help guide and solve the problems of inefficient energy production and unstable power output in wind power systems.The purpose of this paper is mainly to explore the influence of different energy storage batteries on various power quality indicators by adding different energy storage devices to the simulated wind power system,and to explore the correlation between systementropy generation and various indicators,so as to provide a theoretical basis for directly improving power quality by reducing loss.A steady-state experiment was performed by replacing the wind wheel with an electric motor,and the output power qualities of the wind power systemwith andwithout energy storagewere compared and analyzed.Moreover,the improvement effect of different energy storage devices on various indicatorswas obtained.Then,based on the entropy theory,the loss of the internal components of the wind power system generator is simulated and explored by Ansys software.Through the analysis of power quality evaluation indicators,such as current harmonic distortion rate,frequency deviation rate,and voltage fluctuation,the correlation between entropy production and each evaluation indicator was explored to investigate effective methods to improve power quality by reducing entropy production.The results showed that the current harmonic distortion rate,voltage fluctuation,voltage deviation,and system entropy production are positively correlated in the tests and that the power factor is negatively correlated with system entropy production.In the frequency range,the frequency deviationwas not significantly correlated with the systementropy production.
文摘Hazelnuts are an economically important nut which is consumed world-wide.It is prone to infection by Aspergillus flavus and contamination with aflatoxins.Taking Tukey’s hazelnuts as a research object,the objective of this study were to(a)quantify respiration rates and(b)dry matter losses(DMLs)and(c)aflatoxin B_(1)(AFB_(1))contamination of naturally stored shelled hazelnuts at different temperatures and water availabilities.Subsequently,shelled hazelnuts were inoculated with additional A.flavus inoculum prior to storage to examine effects on dry matter losses and on AFB_(1) contamination.Maximum respiration of hazelnuts and associated mycoflora was under wetter conditions of 0.90~0.95 water activity(aw=12.5%~18%moisture content).This resulted in between approx.10%DML at 25 and 30℃after 5 days storage.Inoculation and storage of shelled hazelnuts+A.flavus inoculum resulted in similar patterns of respiration with optimal levels at 25~30℃and>0.90 aw.Indeed,AFB_(1) contamination was highest at the maximum water levels tested of 0.90 aw.Indeed the contamination level exceeded the legislative limits set by the EU for AFB_(1) contamination of these nuts.Correlation between DMLs and all the AFB_(1) data in both sets of studies showed that very small changes in DML due to poor drying or storage of≥0.6%resulted in AFB_(1) contamination levels exceeding the EU legislative limits.Thus,efficient drying and safe monitored storage is necessary to minimise the risk of AFB_(1) contamination in this economically important commodity and to avoid exposure of consumers to such toxins.
文摘Moran considered a dam whose inflow in a given interval of time is a continuous random variable. He then developed integral equations for the probabilities of emptiness and overflow. These equations are difficult to solve numerically;thus, approximations have been proposed that discretize the input. In this paper, extensions are considered for storage systems with different assumptions for storage losses. We also develop discrete approximations for the probabilities of emptiness and overflow.
文摘High postharvest losses in developing countries negate the efforts geared towards improving food security. Poor produce quality including high prevalence of mycotoxin contamination is another significant problem. Appropriate postharvest handling and processing provide opportunities to reduce postharvest losses and improve food safety. This study was aimed at establishing the postharvest handling practices and estimating qualitative and quantitative postharvest losses for maize, millet, sorghum, beans, groundnuts, cassava, and sweet potatoes among farmers in 3 districts (Kamuli, Apac and Nakasongola) in Uganda, representing different agro-ecological zones. The study was done in late August 2014 after the first season harvests (June-August). Farmer interviews, focus group discussions and key informant interviews were used to collect data on postharvest loss estimates and postharvest handling practices. Samples of the different foods were collected and analyzed for physical quality characteristics, mould count and aflatoxin contamination using standard laboratory procedures. The results show predominance of rudimentary and inappropriate postharvest handling methods. Postharvest loss estimates were generally high, with values of 41%, 33%, 33%, 26%, 31%, 22%, 17% and 19% for maize, millet, sorghum, beans, groundnuts, cowpea, sweet potatoes and cassava respectively. The highest loss for all the crops was recorded at storage. Prevalence of aflatoxin contamination was 44%, 91%, 55%, 36%, 35% and 60% for maize, sorghum, groundnuts, millet, sweet potatoes and cassava respectively. Sorghum, maize and groundnuts were found to have the highest aflatoxin contamination levels. Chi-square test (p = 0.024, odds ratio = 5) showed that grain dried on bare ground had higher aflatoxin levels than that dried on a covered surface. The findings of this study reveal a serious need for postharvest interventions as a strategy to address food security.
文摘Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.
基金supported in part by the Shenzhen Collaborative Innovation Special Plan International Cooperation Research Project(No.GJHZ20220913144400001)the General Research Project of Shenzhen Science and Technology Plan(No.JCYJ20220818100000001).
文摘In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the iron loss of SRS/G is mainly studied to reduce the motor loss and improve the power generation efficiency.Then,the energy storage of hybrid EVs can be effectively improved.Secondly,a magnetic flux density(MFD)waveforms solution method is proposed to solve the difficulty in calculating the iron loss of the SRS/G.Compared with the commonly used finite element method,the proposed solution method has the advantages of simple,fast and small computational amount.Meanwhile,considering the different operating conditions of SRS/G,the iron loss models for both the time-domain and frequency-domain are established.In addition,the calculation formula of the variable coefficient Bertotti three-term loss separation is improved.As the hysteresis loss coefficient,the Steinmetz coefficient and the stray loss coefficient are respectively fitted by the Fourier fitting method.This method is also applied to solve the iron loss of SRS/G.Finally,through an experimental verification,it is indicated that the development of proposed method has high accuracy.
文摘The effects of treatment of chlorine dioxide （C1Oz） gas on postharvest physiology and preservation quality of green bell peppers were studied. Green bell peppers were collected in bags and treated with 0, 5, 10, 20, and 50 mg L^-1 ClO2 gas at 10±0.5℃ for over 40 d, and the changes in postharvest physiology and preservation quality of the peppers were evaluated during the storage. The inhibition of rot of the peppers was observed for all the tested ClO2 gas treatments. The rot rates of the treated samples were 50% lesser than those of the control after day 40 of storage. The highest inhibitory effect was obtained after 50 mg L^-1 ClO2 gas treatment, where the peppers did not decay until day 30 and showed only one-fourth of the rot rate of the control at day 40 of storage. The respiratory activity of the peppers was significantly （P〈0.05） inhibited by 20 and 50 mg L^-1 ClO2 treatments, whereas no significant effects on respiratory activity were observed with 5 and 10 mg L^-1 ClO2 treatments （P〉0.05）. Except for 50 mg L^-1 ClO2, malondialdenyde （MDA） contents in the peppers treated with 5, 10, or 20 mg L^-1 ClO2 were not significantly （P〉0.05） different from those in the control. Degradation of chlorophyll in the peppers was delayed by 5 mg L-1ClO2, but promoted by 10, 20, or 50 mg L^-1 ClO2. The vitamin C content, titratable acidity, and total soluble solids of the peppers treated by all the tested ClO2 gas did not significantly change during the storage. The results suggested that ClO2 gas treatment effectively delayed the postharvest physiological transformation of green peppers, inhibited decay and respiration, maintained some nutritional and sensory quality, and retarded MDA accumulation.
基金financial support in the form of a Project Grant (IS-STAC/CO2-SR-79/10/G)
文摘Investigating the immobilization of CO2,previous basalt-water-CO2 interaction studies revealed the formation of carbonates over a short period,but with the extensive formation of secondary silicates(SS).The mechanisms involved in these processes remain unresolved,so the present study was undertaken to understand secondary mineral formation mechanisms.XRPD and Rietveld refinement data for neo-formed minerals show a drastic decrease in the Ca-O bond length,with the calcite structure degenerating after 80 h(hours).However,SEM images and EDS data revealed that a longer interaction time resulted in the formation of chlorite and smectite,adjacent to basalt grains which prevent basaltwater-CO2 interaction to form carbonates,thus restricting carbonate formation.As a result of this,the CO2 mineralization rate is initially high(till 80 h),but it later reduces drastically.It is evident that,for such temperature-controlled transformations,low temperature is conducive to minimizing SS surface coating at the time of mineral carbonation.
文摘In China, the quantity of farmer＇s grain storage covers about 40% of the total grain yield every year. While, the losses of farms＇ grain storage are up to 8%, which is due to the lack of grain storage facility and technology. The losses of farmer＇s grain storage could reach nearly 20 million tons every year. In this paper, the current situation and development of grain storage technology and facility for Chinese farmers were presented. And a series of policy and research work for reducing the losses of farms＇ grain storage was introduced. The large scale farmers are now developing quickly in China, the new storage warehouse and mechanized facility should be developed adaptively. So, the new storage technology and policy to meet the need of large scale farmers were also introduced in this paper.
基金Supported by National Key R&D Plan(2017YFC0405201,2018YFC0407404)Achievements Transformation Project of China Institute of Water Resources and Hydropower Research(SE10003A012017)
文摘There are many reservoirs in China,and serious reservoir sedimentation affects reservoir function and reservoir safety.It is of great significance for restoring the reservoir capacity,improving the efficiency of the reservoir and prolonging the service life of the reservoir to carry out the research on reservoir sedimentation control and storage capacity recovery technology,in the case of fewer and fewer good dam sites suitable for the construction of the reservoir and the increasing accumulation of reservoir sedimentation.In this paper,influence factor of the storage loss,sedimentation control and reservoir capacity recovery technology in China are briefly reviewed.It is necessary to carry out research work on reservoir sedimentation investigation and reservoir siltation mechanism and control measures.
文摘Agricultural control systems are characterized by complexity and uncertainly. A skilled grower can deal well with crops based on his own intuition and experience. In this study, an intelligent optimization technique mimicking the simple thinking process of a skilled grower is proposed and then applied to dynamic optimization of temperature that minimizes the water loss in fruit during storage. It is supposed that the simple thinking process of a skilled grower consists of two steps: 1) “learning and modeling” through experience and 2) “selection and decision of an optimal value” through simulation of a mental model built in his brain by the learning. An intelligent control technique proposed here consists of a decision system and a feedback control system. In the decision system, the dynamic change in the rate of water loss as affected by temperature was first identified and modeled using neural networks (“learning and modeling”), and then the optimal value (l-step set points) of temperature that minimized the rate of water loss was searched for through simulation of the identified neural-network model using genetic algorithms (“selection and decision”). The control process for 8 days was divided into 8steps. Two types of optimal values, a single heat stress application, such as 40℃, 15℃, 15℃, 15℃, 15℃, 15℃, 15℃and 15℃, and a double heat stress application, such as 40℃, 15℃, 40℃, 15℃, 15℃, 15℃, 15℃and 15℃, were obtained under the range of 15℃￡T￡40℃. These results suggest that application of heat stress to fruit is effective in maintaining freshness of fruit during storage.
