Applying direct digital control

One particular aspect of a wide range of HVAC research at the US Center for Building Technology concerned interfacing DDC with the pneumatic system for one of the existing air handling units at the CBT building itself. Using solenoid air valves induced both positive and negative air leaks in the pneumatic system; this did not occur with motorised pressure regulators, though these produced a time delay whenever the regulator's direction of rotation was reversed. Details are given of an adaptive PI algorithm with a self‐tuning regulator approach, developed at CBT and implemented on the air handler in question. From the experience, it is strongly recommended that such an algorithm should be implemented on a positional basis.     

近10年早期肠内外营养对急性胰腺炎预后的Meta分析

目的:分析2004—2014年早期肠内外营养对急性胰腺炎预后的影响及并发症。方法:应用计算机检索2004年1月—2014年1月国内外文献数据库,对急性胰腺炎进行肠内外营养支持治疗的预后对比。结果:对于急性胰腺炎,早期肠内营养较肠外营养可降低其病死率、减少感染率、缩短住院时间、减少并发症的发生。结论:对于急性胰腺炎患者,可尽早进行早期肠内营养进行营养支持治疗。     

Mobile phone & PMP手持设备声学设计应用(上)

电声组件主要包含麦克风(Microphone)、受话器(Receiver)以及扬声器(Loudspeaker),要进行设备的声学设计,必需先了解电声组件的特性及相关测试标准.文中简要概述了电声组件选择要领与发展趋势,分析了电声组件于手持系统的配置要领.并详细阐述了声音测试国际标准及其测试方法.     

Analyse der Mikrostruktur und des Eigenspannungszustandes seilverstärkter Aluminiumstrangpressprofile

Analysis of the microstructure and the residual stress state of aluminium extrusions reinforced with ropes Closed profiles of the aluminium wrought alloy EN AW‐6060 have been in‐situ‐reinforced during the extrusion process with ropes built by wires drawn of the nickel‐based alloy Inconel 601 (2.4851). These profiles have been investigated with non‐destructive and semi‐destructive testing methods regarding the residual stresses evolving during cooling from extrusion temperature to room temperature. The results obtained via X‐ray diffraction and hole drilling method have been compared with simulations using a simplified model of the compound investigated. Thereby, compressive residual stresses appearing during the cooling process have been detected parallel to the rope axis nearby the rope‐matrix‐interface because of plastic flow of the matrix material. Additionally, the microstructure of the extruded composite has been analysed focussing on the contingent formation of intermetallic phases at the rope‐matrix‐interface and on the influence of the reinforcements on the longitudinal weld.     

Impact of European standard EN15251 in the energy certification of services buildings—A Portuguese study case

In Europe, about 40% of the energy is consumed in buildings, more than by industry or transport. However, there is a great potential for energy savings in this field, often at little cost. A new European directive and several European standards, including the comfort standard EN15251, were created to develop comfortable and efficient buildings.