An air-spring standing platform does not increase overall movement or metabolic cost during simulated work tasks

Due to the increased popularity of standing-based occupational work stations there is a growing need to understand the impact of ergonomic aids such as standing mats. In particular, while standing mats have been studied in relation to musculoskeletal discomfort and pain, there have been no studies exploring the effects of their use on metabolism and caloric expenditure. The purpose of this study was to examine the metabolic, biomechanical, and pain/discomfort responses to the use of an air-spring standing mat over a 2-h work-simulated standing period. Sixteen participants visited the lab on two separate occasions, each to perform a 2-h standing simulated-work session, once with and once without a standing mat. Metabolic data were recorded at the start, midpoint, and end of the standing sessions. Force plate centre of pressure (COP) and visual analog discomfort score (VAS) measurements were taken every 15 min. Results demonstrated that there was no difference in caloric expenditure between the two sessions. COP variables demonstrated less movement on the standing mat compared to the control day; however, only one of the eight variables (root-mean-square velocity in the medial-lateral direction) was statistically significant (p = 0.02). VAS scores showed no clear benefit of the standing mat on low back or lower limb discomfort. The short-term introduction of an air-spring standing mat during simulated work tasks appears to have no clear benefits on energy expenditure, biomechanical centre of pressure variables, or for alleviating musculoskeletal discomfort. Whether longer term exposure to this type of mat has differential effects remains to be addressed.     

钢铁企业日际煤气最优混合配比的算法研究

钢铁企业根据日际生产计划,可以确定日际生产的副产煤气总体积、各煤气消耗设备的热量需求。为进一步确定各设备消耗的混合煤气中的煤气配比,使煤气产耗平衡,提出混合煤气逆向分解方法,将各设备消耗的混合煤气中所包含的单一煤气成分体积,表示为各设备获得热量与混合煤气热值的函数,在此基础上建立日际煤气最优混合配比算法模型。该模型以各设备的混合煤气热值及热量作为决策变量,以各煤气消耗设备的热量偏差最小为目标,综合考虑各煤气设备的热值要求、自备电厂的热值、热量要求及煤气体积守恒等约束条件。采用遗传算法求解,并利用遗传算法基因初始化的范围区间控制混合煤气的热值范围。算例结果表明:建立的日际煤气最优混合配比算法模型,在优化煤气分配的同时,显著减少了约束方程及决策变量的数量,为钢铁企业日际煤气平衡调度提供了理论支撑。     

滴形管束换热及流阻特性的实验研究

对空气横掠叉排滴形管束的放热及流阻特性进行了实验研究。讨论了排列方式对管束平均放热及阻力系数的影响以及平均换热系数随流动方向管排数而变化的规律。给出了计算平均换热系数及阻力系数的实验关联式。在传热实验中，采用了热质比拟原理及萘升华技术。实验的雷诺数范围为１００００～１２００００。实验结果表明，滴形管束和圆管管束相比具有强化传热及节约能源的双重优点。     

Porcine G0/G1 Switch Gene 2 (G0S2) Expression is Regulated During Adipogenesis and Short-Term In-Vivo Nutritional Interventions

Adipose triglyceride lipase (ATGL), catalyzing the initial step of hydrolysis of triacylglycerol (TAG) in adipocytes, has been known to be inhibited by G0/G1 switch gene 2 (G0S2). In this study, we report the porcine G0S2 cDNA and amino acid sequences as well as the expression level of porcine G0S2. The porcine G0S2 mRNA was abundantly expressed in adipose tissue and liver among various tissues. In adipose tissue, porcine G0S2 expression was 16-fold higher in the fat cell fraction than the stromal vascular fraction. The G0S2 level increased significantly during adipogenesis in vitro and in vivo. These data indicate that G0S2 expression is closely associated with lipid accumulation and adipogenesis. Considering G0S2 as an inhibitor of cell proliferation, the relatively low levels of G0S2 in preadipocytes and adipose tissues of fetal and neonatal pigs compared to adipocytes and adipose tissues of adult pigs may allow the fast cell proliferation rates. Further studies showed that a short-term 24-h fast down-regulated G0S2 expression and increased ATGL expression in adipose tissue; however, a long-term calorie restriction for 8 days had no influence on the level of G0S2 but increased ATGL expression. Therefore, porcine G0S2, which is both a negative regulator of ATGL-mediated lipolysis and cell proliferation in adipose tissue, can be down-regulated in vivo by a short-term 24-h fast followed by increased ATGL-mediated lipolysis.     

西门子T—M集散系统AS215子系统在太钢五号焦炉控制中的应用

本文介绍了采用集散系统AS－215实现焦炉控制的系统构成和相应的软硬件设计，并且介绍用AS－215实现对焦炉控制的几个特殊方法。