智能低温冷冻库在纸质档案杀虫中的应用研究

智能低温冷冻库通过缓慢循环降温软件系统控制PLC调节库房内温度,使库房内温度按系统预设程序降温曲线阶梯性缓慢降温,能避免冷冻杀虫过程中害虫假死现象,实现杀灭档案害虫。本课题以花斑皮蠹、黑毛皮蠹和烟草甲为供试试虫,经过120小时(约5天)的冷冻实验后,常温下放置24小时后观察,发现害虫致死率达100%。通过对实验前后档案纸张和档案包装箱质量进行对比,发现低温冷冻杀虫实验对档案纸张含水量影响不显著。     

Report:Influence of freezing rate on cryo-damage of cementitious material

We report an experimental investigation on the impact of the freezing rate on the cryo-deformation and cryo-damage of cementitious materials. Saturated, dried and air-entrained mortar specimens are subjected to laboratory freeze-thaw cycles under three freezing rates without moisture exchange with the environment. In addition to basic mechanical properties and pore distribution, the measurement is also effectuated for freezing expansion, residual deformation of the specimens in each cycle. From the results it is observed that a high freezing rate does augment the freezing expansion of material while the cryo-damage is more important for a low freezing rate. Accordingly, both the freezing rate and freezing duration should be taken into account for the cyro-damage extent of cementitious materials.     

Communication,Liminality, and Hope: The September 11th Missing Person Posters

Immediately following the attacks on the World Trade Center on September 11, 2001, family and friends of victims missing in the towers began placing “Missing Person Posters” of their loved ones around New York City. In this paper, we argue that the posters represent a powerful response to a traumatic and in some ways unprecedented situation, a response that transformed the death of loved ones from a reality or future certainty into a probability made possible by the searchers' desire, emotions, or imagination. We demonstrate how the posters, operating in the “subjunctive” voice, transformed the “liminal” space between life and death and “haunted” onlookers, so that survivors and spectators alike could ponder the possibilities of a world that would “hopefully” turn out for the best. We also consider the implications of the posters for those who were unable to acknowledge the loss of their loved ones.     

Heat transfer and parametric studies of an encapsulated phase change material based cool thermal energy storage system

INTRODUCTION Cool thermal energy storage (CTES) using the latent heat concept as an alternative to sensible heat storage offers a good option because of its high storage density and the nearly constant temperature heat removal characteristics during the discharging cycle. Since the principle of latent cool storage nec- essarily involves a change of state, heat transfer must occur in different modes depending on the state of charging and discharging. During the periods of low cooling dema…