天然和人工叠加流场下弥散试验研究

在污灌区浅层含水层进行了现场弥散试验,采用氚做为示踪剂,瞬时投放.因为天然流速较弱,通过注水形成天然的和人工的叠加流场.根据流场特性。建立以Φ-Ψ坐标表示的移流弥散数学模型.采用有限差数值方法求解,其中二维模型应用分裂格式.通过计算的浓度曲线与实验曲线拟合,求得纵、横向弥散率.     

建立地震动物试验场推进地方地震事业发展

本文介绍了地震动物试验场建立、动物观测、数据处理和饲养管理等方面的工作，为动物习性异常与地震关系的研究积累了可贵的观测资料，对于动物的行为异常预报地震具有一定的参考价值。     

强震前淮北台地倾斜短临异常的探讨

地倾斜观测是目前我国作为探索地震前兆的重要手段之一,实践证明地倾斜与地震存在着一定的对应关系.本文尝试利用淮北台FSQ型及JB型倾斜仪的观测结果,通过分析,获取与全球、全国强震有关的短临前兆信息以及总结其基本特征,得到了一些经验性认识.     

PXW型摆辗机摆动机构运动学问题初探

给出了PXW型摆辗机摆头运动机构的机构运动简图,并据此认为具有多种摆头运动轨迹之摆辗机摆杆轴线上除顶点以外的各点只能是作球面运动,因而以往在摆头运动轨迹分析中将其简化为平面杆系势必引入误差.注意到这一点将有助于摆辗机的结构设计和对摆辗加工中应力-应变的分析.     

江苏新沂市越流含水层的地下水资源评价

中国利用越流含水层作为城市供水水源地的实例并不多见。本文根据实际开采资料,利用伽略金（Ｇａｌｅｒｋｉｎ）有限元法计算当补给层水头变化时越流含水层的地下水资源,并提出水位预测的方法。还利用补给层的水量平衡评价越流含水层开采量的保证程度,预测了新水源地投产后对老水源地的影响。本文对于正确认识越流含水层的地下水资源特性及其在城市供水中的意义有重要参考价值。     

Assessment of cervical range of motion,cervical core strength and scapular dyskinesia in violin players

Background. Playing the violin can lead to asymmetric postures which can affect the cervical range of motion, cervical core strength and scapular stability. Objective. The objective of the study was to assess the cervical range of motion, cervical core strength and scapular dyskinesia in violin players and non-players of the same age group. Methods. An inclinometer was used to assess the cervical range of motion, pressure biofeedback was used to assess cervical core strength and scapular dyskinesia was also assessed in 30 professional violin players (18–40 years) compared with 30 age-matched non-players. Analysis was done using an unpaired t test. Results. Significant change was seen with respect to extension (p?=?0.051), cervical core strength (p?=?0.005), right (Rt) superior angle 0° (p?=?0.004), Rt superior angle 45° (p?=?0.015) and Rt inferior angle 90° (p?=?0.013). Conclusion. This study shows a significant difference in extension range of motion and cervical core strength of violin players. Also, there was scapular dyskinesia seen at 0° and 45° right-side superior angle of the scapula and 90° right-side inferior angle of the scapula.     

Life cycle assessment of spray dried soluble coffee and comparison with alternatives (drip filter and capsule espresso)

This paper aims to evaluate the environmental burdens associated with spray dried soluble coffee over its entire life cycle and compare it with drip filter coffee and capsule espresso coffee. It particularly aims to identify critical environmental issues and responsibilities along the whole life cycle chain of spray dried coffee. This life cycle assessment (LCA) specifically uses foreground data obtained directly from coffee manufacturers and suppliers. Aside from energy consumption and greenhouse gases emissions, water footprint is also studied in detail, including regionalization of water impacts based on the ecological scarcity method 2006. Other impact categories are screened using the IMPACT 2002+ impact assessment method.The overall LCA results for a 1 dl cup of spray dried soluble coffee amounts approximately to 1 MJ of primary non-renewable energy consumption, to emissions of 0.07 kg of CO_2-eq, and between 3 and 10 l of non-turbined water use, depending on whether or not the coffee cultivation is irrigated and wet treated. When considering turbined water, use can be up to 400 l of water per cup. Pouch – and to a lesser extent metal can packaging alternatives – show lower environmental burdens than glass or sticks.On average, about one half of the environmental footprint occurs at a life cycle stage under the control of the coffee producer or its suppliers (i.e., during cultivation, treatment, processing, packaging up to distribution, along with advertising) and the other half at a stage controlled by the user (shopping, appliances manufacturing, use and waste disposal). Key environmental parameters of spray dried soluble coffee are the amount of extra water boiled and the efficiency of cup cleaning during use phase, whether the coffee is irrigated or not, as well as the type and amount of fertilizer used in the coffee field. The packaging contributes to 10% of the overall life cycle impacts.Compared to other coffee alternatives, spray dried soluble coffee uses less energy and has a lower environmental footprint than capsule espresso coffee or drip filter coffee, the latter having the highest environmental impacts on a per cup basis. This study shows that a broad LCA approach is needed to help industry to minimize the environmental burdens directly related to their products. Including all processes of the entire system is necessary i) to get a comprehensive environmental footprint of the product system with respect to sustainable production and consumption, ii) to share stakeholders responsibility along the entire product life cycle, and iii) to avoid problem shifting between different life cycle stages.     

Determination of pendimethalin (PROWL®480 EC) spray drift from ground applications

Abstract

Pendimethalin herbicide (PROWL^®480 EC) spray drift was determined from ground applications representing the highest rate applied to corn in eastern Canada. A novel drift collector pattern was laid out on the ground immediately before herbicide application. Most of the drift collectors were located downwind of the application target area. The maximum labelled rate of 1.68 kg ai/Ha was applied on 2 occasions on separate sites. In both applications, drift collector cards indicated that concentrations of pendimethalin were not detectable outside the target zone (<0.01 μg/cm²) at or beyond the 10 metre drift collector stations. Risk assessment calculations indicated that non‐target organisms would not be at significant risk from off‐site movement of pendimethalin.     

Weight comparisons and litter size manipulation in Columbian ground squirrels (Spermophilus columbianus) show evidence of costs of reproduction

I studied reproductive costs in the female Columbian ground squirrel (Spermophilus columbianus) using individually marked animals. I compared weight changes during the active season and over winter, and mortality for females that did and did not wean young. Females raising young were heavier at emergence in that spring than unsuccessful ones. Females that did not raise young gained more weight during summer, were heavier than successful females at the time of entry into hibernation, and were heavier emerging from hibernation the following spring. Over-winter mortality was higher for females that reared young compared to reproductively unsuccessful females. A food supplementation experiment showed that energy-rich food can accelerate individuals’ weight gain. Interactions between litter size, birth weight, weight at emergence from the natal burrow, survival of young to yearling age, and maternal fitness were also studied. Litter sizes were experimentally manipulated to evaluate how females cope with costs of rearing one additional young. Birth weight of juveniles was positively correlated with survival to emergence from the natal burrow and with survival to yearling age. Partial litter loss was higher in experimentally enlarged litters than in either experimentally decreased or control litters. Total litter loss, survival of adult females or the probability of weaning young the following year were not affected by the litter size manipulation. Females appear to adjust the size of their litter before birth, and to some extent during lactation, to their ability to wean young. Received: 20 January 2000 / Received in revised form: 12 March 2000 / Accepted: 18 March 2000     

LNG船舶锚泊安全距离定量计算建模

为保障液化天然气船舶(LNG船舶)锚泊安全,提出了一种基于船舶漂移运动和船舶碰撞风险的锚泊安全距离计算方法.首先,结合船舶运动数学模型,通过蒙特卡洛模拟LNG船舶走锚漂移运动,得出走锚漂移方向概率密度函数,从而确定船舶走锚漂移横向、纵向距离;同时,结合船舶碰撞概率模型、船舶碰撞损害模型和LNG火灾模型,建立LNG船舶碰撞风险模型,确定满足碰撞概率和风险可接受的安全距离.最后,比较两种模型计算结果,并取其较大值作为LNG船舶锚泊安全距离.结果表明,LNG船锚泊安全距离不仅与环境水域的风、流情况有关,还与附近水域内船舶大小及速度有关.建议交通管理中需结合水域环境特征和水域船舶特点确定LNG船舶的锚泊安全距离.