Cold chain containers are extensively applied to the fruit transport sector, and the storage time is a key performance indicator. The correlation between fruit respiration and storage longevity has not been fully elucidated. A new theoretical model is constructed by coupling conduction-convection-radiation-respiratory heat transfer, taking lemon, mango, and orange as examples. As for the cold chain container, heat transfer was constructed by shape factors, gravity-temperature difference coupling, and the radiation network method. As for fruit, the nonlinear model is used to fit the respiratory intensity at different temperatures. Theoretical predictions were compared with experimental data and simulation outcomes, which demonstrate the ability of the proposed theoretical model to serve as a substitute for simulation models in predicting experimental outcomes. Compared with the theoretical model without respiratory heat, the high prediction accuracy for the experimental results was obtained by the new theoretical model with respiratory heat. These findings reveal how fruit respiration impacts storage time in cold chain units, thereby guiding design optimization to minimize energy loss.

The change in moisture content (MC) will lead to a change in the mechanical properties of molded fiber products (MFP). Therefore, for predicting the mechanical properties of MFP, it is necessary to construct a mechanical constitutive model with the MC term. In this study, quasi-static uniaxial tensile tests of sugarcane bagasse-molded fiber products (SBMFP) were conducted at different MCs (0 17

The polymeric films exhibit a significant temperature effect, so their application is limited. This paper explores the influence law of temperature on the mechanical properties of PE/PA/PE film through the uniaxial tensile test at different temperatures (− 20 to 60 °C). The true stress-strain curve of the material is obtained by the finite element correction method. The exponential function can describe the trend of the elastic modulus and yield strength with temperature. A constitutive equation with a temperature term is established and verified based on the improved shape function of the Sherwood-Frost constitutive model and the Johnson-Cook constitutive model. The applicability of the proposed model was further validated by simulating the static compression of inflation bags at an extended temperature range. In the application process, this paper demonstrates the accuracy of the simulation model through the use of a scanner. The results show that the constitutive equation can effectively predict the mechanical properties of inflatable products at different temperatures in the range of experimental studies.

The storage time of cold box is an important subject. At present, the research method of the storage time is mainly an experiment, and the theoretical research is incomplete. Therefore, in this work, theoretical modeling combined with a network method of radiation heat transfer, the shape factor of heat conduction, and sensible heat of refrigerant were proposed to calculate the storage time of a cold box at various ambient temperatures and amounts of refrigerant. The experimental and simulation results were used to verify the theoretical modeling of the storage time. The influences of the sensible heat of refrigerant and radiation heat transfer in the cold box were analyzed. The stability of the theoretical modeling was studied via simulation of the different cold box and refrigerant materials. The results of the accuracy of the theoretical model confirmed that the maximum error between the theoretical and the experimental storage times is 8.45%, and the error between the theoretical and the simulation results is 7.51%, indicating that the sensible heat of refrigerant and radiation heat transfer have big impacts on the storage time. The stability of the theoretical model is confirmed under the different box and refrigerant materials, and different shapes of refrigerant. The storage time model has stability on different box materials and refrigerant materials. The theoretical model can be severed as a fundamentally guidance for the cold box production design.

This paper aims to investigate the migration of antimony in polyethylene terephthalate（PET） beverage bottles and recycled food-grade regenerated polyethylene terephthalate（rPET） chips and the effects of food simulation solution and temperature on the migration behavior of antimony in PET beverage bottles and rPET chips. The samples of the PET beverage bottle and rPET slice were completely soaked in 4%（volume fraction） acetic acid, 10%（volume fraction）, and 20%（volume fraction） ethanol food simulation solution. The antimony in the PET beverage bottle and rPET slice was quantitatively analyzed by inductively coupled plasma mass spectrometry（ICP-MS）. The effects of different food simulation solutions and temperatures on the migration diffusion coefficient were analyzed by fitting the experimental migration and the prediction curve of the migration model. Results showed that when the migration equilibrium was reached and the temperature was 60 ℃, the migration amount of antimony in rPET chips to different food simulation solutions was higher than that in PET beverage bottles to different food simulation solutions. Comparing the three food simulation solutions, the diffusion coefficient of antimony in the PET beverage bottle and rPET slice to 4% acetic acid food simulation solution was higher. At different temperatures, the experimentally measured value of antimony migration from a PET beverage bottle to 4% acetic acid fitted well with the prediction curve of the migration model（the fitting degree was more than 0.9）. The higher the temperature was, the higher the diffusion coefficient was, and it conformed to the Arrhenius relationship.

The random distribution model (RDM) and uniform distribution model (UDM) were used to simulate the thermal sterilization of canned fruit. The RDM was established with the radiation function, and the stability of RDM results was analyzed by simulating temperature change during thermal sterilization and determining the sterilization parameter F value of the slowest heating zone (SHZ). The performance of the distribution models in simulating thermal sterilization heating process of canned fruit with different shapes was studied using the UDM and RDM of canned yellow peach (hemispherical shell), pear (sphere), and coconut (cube). Simulation results were compared with experimental results. The flow field and temperature field distributions were used in analyzing the influence of fruits shape on the accuracy of the models. The simulation results of different RDMs were consistent with the temperature change and F value, indicating that the RDMs had stable simulation results. When the contact between two types of fruit was a point, the UDM can be used in the numerical simulation of thermal sterilization. When the contact was a non-point, the RDM was more accurate in simulating thermal sterilization. This study provides constructive suggestions for the simulation of thermal sterilization of canned fruit with different shapes.

A theoretical model coupling with conduction-convection-radiation was proposed to calculate the storage time of a cold box. The experimental and numerical results at amounts and positions of a refrigerant were used to verify the theoretical model of the cold box. The numerical results at various ambient temperatures were also used to verify the theoretical model. The theoretical model analyzed the influences of different positions of the refrigerant and the thickness of the cold box on the storage time. The determination value K was proposed. Results show that the maximum error between theoretical results and experimental and numerical results was 2.26 %, indicating that the theoretical model of storage time is consistent with the experimental and numerical results and the theoretical model can replace numerical simulation to reduce time. The storage time from the refrigerant position from bottom to top gradually decreases. The best thickness of the cold box was 27.5-38.75 mm, which was independent of the positions of the refrigerant, ambient temperatures, materials of the cold box and the refrigerant, and the sizes of the cold box.

目的 为解决缓冲材料发泡聚乙烯因蠕变引起保护失效的问题,基于Burgers模型,分析载荷、应力保持时间对EPE压缩蠕变行为的影响.方法 根据不同应力下的不同保持时长压缩蠕变试验结果,拟合EPE不同应力下的压缩蠕变试验数据,分析不同应力、应力保持时间下的EPE蠕变过程中蠕变总量、弹性应变、黏弹性应变和黏性应变的变化规律.结果 Burgers四元件力学模型对EPE不同应力下的压缩蠕变实验数据拟合度为0.9924～0.9989.在同一应力保持时间下,随着应力从3.3 kPa增加到5.3 kPa,弹性模量E1、弹性模量E2、黏度系数η2、黏度系数η1都逐渐减小,蠕变总量、黏性应变呈非线性显著增加,弹性应变、粘弹性应变呈线性微量增加;在同一应力下,随着应力保持时间从20 d增加到120 d,弹性应变一直保持不变,占蠕变总量的比例降低,粘弹性应变先微量增加后保持不变,占蠕变总量的比例降低,黏性应变增加,占蠕变总量的比例增加.结论 Burgers模型可较准确地模拟EPE不稳定蠕变阶段和稳定蠕变阶段的压缩蠕变行为;应力的增加导致EPE抵抗变形的能力变弱,引起蠕变量增加;应力保持时间的增加对弹性应变无影响,对稳定蠕变阶段的黏弹性应变无影响,对黏性应变的增加有显著影响.

BACKGROUND To improve the utilization rate of cinnamon essential oil and compensate for the shortcomings of its easy decomposition and oxidation, the microemulsion of cinnamon essential oil was prepared using Tween 80 and anhydrous ethanol as surfactant and cosurfactant, respectively. The effects of the surfactant type, K-m value, preparation temperature and aqueous pH on the quality of the microemulsion were studied via a pseudo-ternary phase diagram. The slow-release performance of cinnamon essential oil microemulsion and the control performance of the insect repellent package on the rice weevil were characterized. RESULTS The results showed that, when Tween 80 was used as a surfactant and anhydrous ethanol was used as a cosurfactant, the K-m value was 3:1, preparation temperature was 40 degrees C, aqueous pH was 5 and prepared cinnamon essential oil microemulsion was of the O/W type. The microemulsion had strong stability and a 81.5-nm concentrated particle size distribution, and possessed excellent embedding and sustained-release effects. The prepared insect repellent active package prolongs the use time and the effect of cinnamon essential oil. The repellent rate of the rice weevil was as high as 100% after 48 h, and the contact mortality and fumigation mortality rates of the rice weevil also reached 96.67% and 86.67%, respectively, after 96 h. CONCLUSION The prepared cinnamon essential oil microemulsion and active packaging had a good sustained-release effect. (c) 2021 Society of Chemical Industry.

This study aimed to improve the strength and hydrophobic properties of polyvinyl alcohol/microfibrillated-cellulose composite films and thereby solve problems such as the poor water resistance of polyvinyl alcohol films and defects in the packaging. Polyvinyl alcohol/microfibrillated-cellulose composite films were prepared with the silane coupling agent KH151. The mechanical, optical, crystalline, and other properties of the composite films were tested. After the modification of the polyvinyl alcohol/microfibrillated-cellulose films, their strength and hydrophobic and barrier property were greatly improved. Moreover, their oxygen transmittance decreased by 85.9%, and the water contact angle of the film surface increased by 44%. The internal structure of a polyvinyl alcohol/microfibrillated-cellulose film is formed by KH151, which improves the strength and barrier properties of the film, forms an alkane-based layer on the film surface, and improves the hydrophobic property of the film. Thermogravimetric analysis shows that the thermal stability of composite materials has been greatly improved.

随着"一带一路"国家战略的落地实施和中国汽车工业的快速稳步发展,如何提升企业的核心竞争力,成为各大汽车生产厂家最为关注的热点.本文以汽车零部件的包装方式为研究对象,统计分析了零部件包装在物流链环节的影响因素,规范了包装定义流程,确定了包装形式选用的办法及对策,并用MTM的办法将不同包装方式的不同环节影响效果量化,根据生产系统中HPV、销售价格、利润等实际情况与MTM量化分析结果价值化分析,计算出了最优的零部件标准包装的选用方案.

中草药提取物作为天然抗菌剂,以其高效、低毒、无污染以及广谱抗菌性等优点代替化学防腐剂广泛应用于食品保鲜中.本文主要从目前具抑菌性中草药的种类出发,介绍了中草药的主要抑菌成分及其作用机理;并对中草药提取物在水果、蔬菜、肉制品、粮食作物以及其他一些食品行业,尤其是果蔬保鲜中的应用方式进行了论述,为包装材料研究者进行中草药提取物的应用提供参考.

A pre-actuation method for initial droplets accurateness of inkjet printing with volatile materials is proposed. Inkjet printing has been used as the low-cost and efficient manufacturing technology indifferent fields. Some fields such as the electronics industry require precise drop-on-demand. The initial droplets, as reported by some research, are different in morphology, trajectory, velocity, and volume from subsequent drops within a burst. In this study, firstly drops dissimilarity caused by evaporation on meniscus surface was investigated. In order to improve the accuracy of initial droplets, the pre-actuating waveform was used to condition the meniscus. Experimental results showed that the input pre-actuation waveform is optimized such that the difference between the initial drops and subsequent drops behavior is minimized.

目的 研究羧甲基壳聚糖溶液浓度和静电纺丝工艺参数对纳米纤维直径的影响.方法 按照静电纺丝的原理,选取溶液浓度、电压、流量和喷头直径等4个影响因素,使用响应面法中的Box-Behnken设计对羧甲基壳聚糖静电纺丝纤维直径进行预测,得到二次多元回归模型.结果 羧甲基壳聚糖溶液浓度、流量、浓度的二次项和喷头直径的二次项对纤维直径影响显著,该模型实验值与预测值高度拟合.结论 通过响应面得到的模型能预测羧甲基壳聚糖纤维的直径,同时明确了羧甲基壳聚糖纤维的最佳电纺参数.

In this paper, composite fiber membranes of cellulose acetate/chistosan (CA/CS) were prepared by electrospinning using two different injection methods involving co-injection and two-step injection. The antibacterial and micro-morphology properties of the CA/CS composite fiber membranes were also investigated. The results show that the optimum conditions of co-injection method were as follows: voltage 13 kV, flow rate 1.0 ml/h, and receiving distance 10 cm. For the two-step injection method, the voltage of 15 kV, flow rate of 1.0 ml/h, and receiving distance of 10 cm were adopted to prepare cellulose acetate membrane at first, and then, the chitosan liquid was injected into the cellulose acetate membrane under the condition of 13 kV voltage and 0.5 ml/h flow rate. The CA/CS composite fiber membrane prepared by the co-injection method had a better fibrous structure arrangement, smooth fiber surface, and uniform thickness, but the poor antibacterial effect was also indicated. However, the two-step injection method has excellent antibacterial effects. When the CS/PEO ratio is 9:1, composite fiber membrane has the best antibacterial property, but the fiber surface is not smooth enough.

目的:设计兼有绿色环保、灵活多变及良好的体验性等优点的化妆品混装缓冲结构及少量使用胶带的外包装箱.方法:研究分析现有化妆品混装电商包装存在的问题,针对现有问题结合实际情况提出瓦楞纸设计方案.结论:采用全瓦楞纸缓冲结构及外包装箱设计在某种程度上可以解决现有问题,为化妆品混装电商包装提供了十分有意义的解决方案.

目的 针对长方体(正方体)自锁底纸盒成型过程中粘合余角底面容易出现卡滞、破损的现象,研究其自锁底纸盒粘合余角底面的切点轨迹.方法 集中研究长方体(正方体)自锁底纸盒的粘合余角底面在成型过程中的切点在三维坐标中的轨迹问题,确定参数轨迹方程为正弦函数曲线.结果 不论长方体的长和宽是否相等,自锁底纸盒粘合余角底面的切点轨迹都是正弦函数曲线.结论 该正弦函数曲线的设计可以避免自锁底纸盒成型过程中出现的卡滞和破损现象,同时使自锁底粘合纸盒的盒底设计更加合理.

本文通过对快消品陈列方式和销售场所的情况调研，阐述了瓦楞纸板展示架的分类及其设计要素。瓦楞纸板展示架根据功能特性可分为销售型和运输型展示架；根据形态不同可分为落地式、柜台式、悬挂式、堆头式、创意式等展示架。瓦楞纸板展示架丰富多样，通过改变造型、结构、装潢、尺寸等设计要素可以使展架具有别致的造型、较高的强度以及方便使用的功能。

The aim of this paper is to develop a new frequency response function- (FRF-) based indirect inverse substructuring method without measuring system-level FRFs in the coupling DOFs for the analysis of the dynamic characteristics of a three-substructure coupled product transport system with rigid and flexible coupling. By enforcing the dynamic equilibrium conditions at the coupling coordinates and the displacement compatibility conditions, a closed-form analytical solution to inverse substructuring analysis of multisubstructure coupled product transport system is derived based on the relationship of easy-to-monitor component-level FRFs and the system-level FRFs at the coupling coordinates. The proposed method is validated by a lumped mass-spring-damper model, and the predicted coupling dynamic stiffness is compared with the direct computation, showing exact agreement. The method developed offers an approach to predict the unknown coupling dynamic stiffness from measured FRFs purely. The suggested method may help to obtain the main controlling factors and contributions from the various structure-borne paths for product transport system.