Dynamic Simulation and Analysis of the Process of Cold-Storage Plate Release Cool in Refrigerator Vehicle

This paper presents a mathematical model for simulating the heat transfer process in a cold-storage plate that can be used in the refrigerator vehicle. The numerical method studied was an enthalpy method. Variation rule between process of release cool and influenced factors were obtained. The effect of solar radiation time was investigated in discharging process. Both increasing the number of cold-storage plate and improving sealed performance of door and compartment can extend release cool time. The results show that according to the different breath heat of goods, reasonable arrangement of number of cold-storage plate can meet cold demand in the transport; solar radiation also has influence to the process of cold-storage plate release cool, with considering cold load caused by solar radiation, release cool time is shortened by 13%.

Seasonal changes of photoperiodic response and inflorescence quality in pot cultivars of Chrysanthemum × grandiflorum grown in greenhouse

The aim of the research was to investigate seasonal changes of photoperiodic response and inflorescence quality in chrysanthemum from the Time group grown all year round without supplementary lighting. Four chrysanthemum cultivars were grown in 12 cycles starting on the second day of each successive month. The first cycle began on 2 January. From the moment of potting, the plants were treated with a short day. In periods of naturally long days, the day was shortened to 10.5 hours through shading. No supplementary illumination was used from November to mid-February (a photoperiod of under 10 hours) to improve light conditions in the period of insolation deficit. In Polish climatic conditions, the shortest photoperiodic responses were recorded usually in the cycles starting in February or March and August or September. An exceptionally longer photoperiodic response was recorded in the cycle including the height of summer, i.e. planting from June to July, when the temperature during the day was very high, and from October to December i.e. in the period of substantial insolation deficit. The highest quality of flower heads was attained by plants potted mostly between 2 March and 2 September and flowering from April - May to November. Those plants developed the greatest number of inflorescences and usually a typical, cultivar-specific colour of the flower. Chrysanthemums potted from 2 June to 2 July, i.e. in the period of the greatest heat, produced inflorescences with the smallest diameter. For the cultivar 'Cool Time', this unfavorable period lasted from 2 April to 2 August.

Study on the Resistance Spot Microwelding Parameters of Copper and Nickel-Plated Steel Dissimilar Metals

0.2-mm-thick copper and 0.3-mm-thick nickel-plated steel dissimilar metals were jointed by resistance spot microwelding. The processing parameters were optimized by orthogonal experimental and influence of processing parameter on the morphology and microstructure of welded joint was studied. The results show that the optimized processing parameters that can get the maximum tensile-shear force are: preheat current is 0.8KA, welding current is 3.5 KA, up time is 0.5ms, preheat current is 2ms, cool time is 0.5ms, welding time is 5ms, and electrode pressure is 20N. With the optimized processing parameters, the tensile-shear force of the welded joint can achieve 108.9N. The microstructures of welded joint that has best tensile-shear force are composed of swirling structure in weld nugget, uniform distribution of copper in weld nugget with a little of nickel.