Although white clover has been widely studied and applied,less is known about its physiological responses to chilling stress in northern China.The effects of acclimation time of chilling stress in the two white clover...Although white clover has been widely studied and applied,less is known about its physiological responses to chilling stress in northern China.The effects of acclimation time of chilling stress in the two white clover cultivars,Rivendel and Haifa,after exposure to 4℃for 0,4,8,12,24 and 48 h were investigated.Seven physiological indexes were measured in shoots of the two cultivars.It was found that Rivendel had a strong ability to maintain the stability of cells,cope with oxidative damage and accumulate osmotic adjustment substances compared with Haifa.In addition,a comprehensive evaluation on the chilling tolerance of the two cultivars based on subordinate function value analysis showed a stronger chilling tolerance of Rivendel than Haifa.展开更多
In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were inve...In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.展开更多
The optimum control strategy and the saving potential of all variable chiller plant under the conditions of changing building cooling load and cooling water supply temperature were investigated. Based on a simulation ...The optimum control strategy and the saving potential of all variable chiller plant under the conditions of changing building cooling load and cooling water supply temperature were investigated. Based on a simulation model of water source chiller plant established in dynamic transient simulation program (TRNSYS),the four-variable quadratic orthogonal regression experiments were carried out by taking cooling load,cooling water supply temperature,cooling water flow rate and chilled water flow rate as variables,and the fitting formulas expressing the relationships between the total energy consumption of chiller plant with the four selected parameters was obtained. With the SAS statistical software and MATHEMATICA mathematical software,the optimal chilled water flow rate and cooling water flow rate which result in the minimum total energy consumption were determined under continuously varying cooling load and cooling water supply temperature. With regard to a chiller plant serving an office building in Shanghai,the total energy consumptions under different control strategies were computed in terms of the forecasting function of cooling load and water source temperature. The results show that applying the optimal control strategy to the chiller plant can bring a saving of 23.27% in power compared with the corresponding conventional variable speed plant,indicating that the optimal control strategy can improve the energy efficiency of chiller plant.展开更多
Several groups in the USA have been working to de-velop a low chill apricot that would ripen its fruits veryearly in the season. Unfortunately, the cultivatcd apricothas been developed mainly from the high chilling Eu...Several groups in the USA have been working to de-velop a low chill apricot that would ripen its fruits veryearly in the season. Unfortunately, the cultivatcd apricothas been developed mainly from the high chilling Euro-pean group within the species Prunus armeniaca. Amongthe five groups within the apricot species, this is the mostrecently evolved and least variable (Bailey and展开更多
The effects of spices（cinnamon,rosemary,clove）extracts and chitosan on microbiological growth,drip loss,color,and lipid oxidation of fresh chilled meat stored for 28 days at 4℃were investigated.There were four trea...The effects of spices（cinnamon,rosemary,clove）extracts and chitosan on microbiological growth,drip loss,color,and lipid oxidation of fresh chilled meat stored for 28 days at 4℃were investigated.There were four treatments：control,coated with spices（cinnamon 1.5 g·L^-1＋rosemary 1.5 g·L^-1＋clove 1.0 g·L^-1）,coated with 0.5%chitosan,coated with spices and chitosan.Chitosan coating resulted in significant inhibition of microbial growth（P〈0.05）,while the lowest microbial counts were obtained in the samples containing both chitosan and spices,indicating a possible synergistic effect.Chitosan and its combinations with spices also showed the most intense antioxidative effect when compared to the controls（P〈0.05）.Meanwhile,chitosan coating could decrease water loss and keep better color of chilled meat.The combined spice extracts and chitosan coating could effectively extend the shelf life of chilled meat.展开更多
This study investigated the growth situation of Listeria monocytogenes on chilled pork and the effect of herbal preservatives on this pathogen. The inhibitions of herbal preservatives were identified. The minimum inhi...This study investigated the growth situation of Listeria monocytogenes on chilled pork and the effect of herbal preservatives on this pathogen. The inhibitions of herbal preservatives were identified. The minimum inhibitory concentrations （MIC） of cinnamon and clove were all 0.79 mg.mL^-1, while the rosemary was 1.58 mg.mL^-1. And the composite herbal preservatives were got through orthogonal experiment. The optimum proportion was as following on agar medium： 1.16 mg.mL^-1 cinnamon＋2.38 mg. mL^-1 rosemary＋3.17 mg. mLl clove （herb combination number 5）, while on chilled pork, the strong inhibition of L. monocytogenes was showed, which demonstrated that the surface application of herb combination resulted in an effective delay of L. monocytogenes growth.展开更多
On going trend of miniaturization in electronic rel at ed parts, which is an average of two times in every 5～7 years introduce grindin g challenges. In grinding process, the surface waviness control of thin parts is ...On going trend of miniaturization in electronic rel at ed parts, which is an average of two times in every 5～7 years introduce grindin g challenges. In grinding process, the surface waviness control of thin parts is an ardent task due to its warpage, induced by the high specific grinding energy (2～10 J/mm 3). Therefore, coolant is often used to avoid thermal damage, obtai n better surface integrity and to prolong wheel life. However coolant, the incomp ressibility media introduce high forces at the grinding zone creating dimensiona l as well as shape instability. In view of these situations chilled air was ap plied in place of conventional coolant. The chilled air is produced using a two -stage vapor compression refrigeration cycle with characteristics of: temperatu re -35 ℃, pressure 0.2～0.3 MPa and flow rate 0.4 m 3/min. Also traces of eco - oil mist that encompass the chilled air are supplied to the grinding zone. B oth chilled air and eco-oil mist are applied through two independent paths of a specially designed twin compartment nozzle for maximizing the penetration. This paper investigates the grinding characteristics of mold insert which is closer to M2 tool steel (component widely used in connector industries) when using chil led air as coolant media. Grinding experiments were conducted using a vitrified bond CBN wheel (B91N100V) and a surface grinder. Initial study was focussed on establishing the most suita ble clamping method for the thin mold insert. FEM analysis and grinding experime nt studies were performed to quantitatively analyze the clamping induced deflect ion. Waviness value (W t) of (24～62) μm was achieved for resin clampi n g whereas (4～8) μm, (4～6) μm were achieved for magnetic and wax clamping res pe ctively. Wax clamping is predominantly used in all the grinding experiments that characterize the grinding process, which use chilled air as the coolant media. Between 0.15 to 0.9 mm 3/mm.s of specific material removal rate, ground sur face temperature of mold insert was increased from 0.3 ℃ to 59.7 ℃ for chi lled air. For the similar grinding conditions with the coolant fluid an increase from 0.9 ℃ to 14.4 ℃ was recorded. With increase of specific material removal rate from 0.15 to 0.65 mm 3/mm.s, F t/F n ratio was increased from (0.2 to 0.4), (0.6 to 1.67) for wet coolant and chilled air respectively. Despite of high F t/F n ratio and ground surface temperature, chilled air method has shown a surface waviness, W t from (2 to 5.6) μm. Microstructure examination of chilled air produced ground surface was comparable to those of using coolant fluids. Surface finish, R a of (0.45～0.7) μm was achieved for mold insert . This work will enable to have clear understanding about the quantitative influe nce of chilled air as well as the clamping method against the surface waviness o f thin mold insert.展开更多
基金Supported by the National Natural Science Foundation of China(31802120)the Natural Science Foundation of Heilongjiang Province of China(LH2021C040)Academic Backbone Fund Project of Northeast Agricultural University。
文摘Although white clover has been widely studied and applied,less is known about its physiological responses to chilling stress in northern China.The effects of acclimation time of chilling stress in the two white clover cultivars,Rivendel and Haifa,after exposure to 4℃for 0,4,8,12,24 and 48 h were investigated.Seven physiological indexes were measured in shoots of the two cultivars.It was found that Rivendel had a strong ability to maintain the stability of cells,cope with oxidative damage and accumulate osmotic adjustment substances compared with Haifa.In addition,a comprehensive evaluation on the chilling tolerance of the two cultivars based on subordinate function value analysis showed a stronger chilling tolerance of Rivendel than Haifa.
文摘In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.
基金Project(G-0805-10156) supported by US Energy Foundation
文摘The optimum control strategy and the saving potential of all variable chiller plant under the conditions of changing building cooling load and cooling water supply temperature were investigated. Based on a simulation model of water source chiller plant established in dynamic transient simulation program (TRNSYS),the four-variable quadratic orthogonal regression experiments were carried out by taking cooling load,cooling water supply temperature,cooling water flow rate and chilled water flow rate as variables,and the fitting formulas expressing the relationships between the total energy consumption of chiller plant with the four selected parameters was obtained. With the SAS statistical software and MATHEMATICA mathematical software,the optimal chilled water flow rate and cooling water flow rate which result in the minimum total energy consumption were determined under continuously varying cooling load and cooling water supply temperature. With regard to a chiller plant serving an office building in Shanghai,the total energy consumptions under different control strategies were computed in terms of the forecasting function of cooling load and water source temperature. The results show that applying the optimal control strategy to the chiller plant can bring a saving of 23.27% in power compared with the corresponding conventional variable speed plant,indicating that the optimal control strategy can improve the energy efficiency of chiller plant.
文摘Several groups in the USA have been working to de-velop a low chill apricot that would ripen its fruits veryearly in the season. Unfortunately, the cultivatcd apricothas been developed mainly from the high chilling Euro-pean group within the species Prunus armeniaca. Amongthe five groups within the apricot species, this is the mostrecently evolved and least variable (Bailey and
基金Supported by the Student Abroad Foundation of Harbin(RC2006LX020003)
文摘The effects of spices（cinnamon,rosemary,clove）extracts and chitosan on microbiological growth,drip loss,color,and lipid oxidation of fresh chilled meat stored for 28 days at 4℃were investigated.There were four treatments：control,coated with spices（cinnamon 1.5 g·L^-1＋rosemary 1.5 g·L^-1＋clove 1.0 g·L^-1）,coated with 0.5%chitosan,coated with spices and chitosan.Chitosan coating resulted in significant inhibition of microbial growth（P〈0.05）,while the lowest microbial counts were obtained in the samples containing both chitosan and spices,indicating a possible synergistic effect.Chitosan and its combinations with spices also showed the most intense antioxidative effect when compared to the controls（P〈0.05）.Meanwhile,chitosan coating could decrease water loss and keep better color of chilled meat.The combined spice extracts and chitosan coating could effectively extend the shelf life of chilled meat.
基金the Student Abroad Foundation of Harbin (RC2006LX020003)
文摘This study investigated the growth situation of Listeria monocytogenes on chilled pork and the effect of herbal preservatives on this pathogen. The inhibitions of herbal preservatives were identified. The minimum inhibitory concentrations （MIC） of cinnamon and clove were all 0.79 mg.mL^-1, while the rosemary was 1.58 mg.mL^-1. And the composite herbal preservatives were got through orthogonal experiment. The optimum proportion was as following on agar medium： 1.16 mg.mL^-1 cinnamon＋2.38 mg. mL^-1 rosemary＋3.17 mg. mLl clove （herb combination number 5）, while on chilled pork, the strong inhibition of L. monocytogenes was showed, which demonstrated that the surface application of herb combination resulted in an effective delay of L. monocytogenes growth.
文摘On going trend of miniaturization in electronic rel at ed parts, which is an average of two times in every 5～7 years introduce grindin g challenges. In grinding process, the surface waviness control of thin parts is an ardent task due to its warpage, induced by the high specific grinding energy (2～10 J/mm 3). Therefore, coolant is often used to avoid thermal damage, obtai n better surface integrity and to prolong wheel life. However coolant, the incomp ressibility media introduce high forces at the grinding zone creating dimensiona l as well as shape instability. In view of these situations chilled air was ap plied in place of conventional coolant. The chilled air is produced using a two -stage vapor compression refrigeration cycle with characteristics of: temperatu re -35 ℃, pressure 0.2～0.3 MPa and flow rate 0.4 m 3/min. Also traces of eco - oil mist that encompass the chilled air are supplied to the grinding zone. B oth chilled air and eco-oil mist are applied through two independent paths of a specially designed twin compartment nozzle for maximizing the penetration. This paper investigates the grinding characteristics of mold insert which is closer to M2 tool steel (component widely used in connector industries) when using chil led air as coolant media. Grinding experiments were conducted using a vitrified bond CBN wheel (B91N100V) and a surface grinder. Initial study was focussed on establishing the most suita ble clamping method for the thin mold insert. FEM analysis and grinding experime nt studies were performed to quantitatively analyze the clamping induced deflect ion. Waviness value (W t) of (24～62) μm was achieved for resin clampi n g whereas (4～8) μm, (4～6) μm were achieved for magnetic and wax clamping res pe ctively. Wax clamping is predominantly used in all the grinding experiments that characterize the grinding process, which use chilled air as the coolant media. Between 0.15 to 0.9 mm 3/mm.s of specific material removal rate, ground sur face temperature of mold insert was increased from 0.3 ℃ to 59.7 ℃ for chi lled air. For the similar grinding conditions with the coolant fluid an increase from 0.9 ℃ to 14.4 ℃ was recorded. With increase of specific material removal rate from 0.15 to 0.65 mm 3/mm.s, F t/F n ratio was increased from (0.2 to 0.4), (0.6 to 1.67) for wet coolant and chilled air respectively. Despite of high F t/F n ratio and ground surface temperature, chilled air method has shown a surface waviness, W t from (2 to 5.6) μm. Microstructure examination of chilled air produced ground surface was comparable to those of using coolant fluids. Surface finish, R a of (0.45～0.7) μm was achieved for mold insert . This work will enable to have clear understanding about the quantitative influe nce of chilled air as well as the clamping method against the surface waviness o f thin mold insert.
