Regional heat safety thresholds for athletics in the contiguous United States

Exertional heat illnesses affect thousands of athletes each year across the United States (U.S.). Heat safety guidelines such as those developed by the American College of Sports Medicine (ACSM) are widely used to direct activities based on environmental conditions but rely on a uniform set of heat safety categories. Due to geographic variations in heat exposure and acclimatization, however, lower heat safety thresholds may be needed in areas with cooler climates. Our study addresses this shortcoming by developing regional guidelines for athletic activity that use relative thresholds of a commonly used heat metric -- the wet bulb globe temperature (WBGT). We employed a unique WBGT climatology for the contiguous U.S. to determine locally extreme WBGTs, defined as the 90th percentile warm season daily maximum value, for 217 stations. Three heat safety regions were identified based on local extremes: Category 3 (WBGTs ≥ 32.3 °C), Category 2 (30.1–32.2 °C), and Category 1 (≤30 °C). Geographically, Category 3 encompasses much of the southeastern quadrant of the U.S. along with portions of the Southwest, and the Central Valley of California; Category 2 areas extend in an arc from the interior Northwest through Nevada and portions of the Midwest, Ohio Valley, and Northeast; and Category 1 locations include the Pacific Coast, New England, and the northern tier of the country. Associated regional activity guidelines based on those developed by the ACSM and the Georgia High School Association (GHSA) were developed for each heat safety region.     

一种简便实用的湿空气性质计算方程

对几个经验的蒸气压力方程以及水汽化潜热方程等进行数理统计处理，给出了这几个经验方程的参数，运用这些经验方程建立了一种湿空气性质计算方程，方程计算结果最大相对误差不超过０．３５０％。关键词     

Wet Canopy Evaporation Rate of Three Stands in Western Sichuan, China

The wet canopy evaporation rate (Er) was calculated by Penman-Monteith combination model based on three assumptions and with meteorological variables 2 m above the canopy in three stands, dominated by spruce (SF), fir (FF) and birch (BF) trees, respectively, in the subalpine forests in western Sichuan, China over a growing season. The total amount of the E was 44.5 mm for SF, 88.5 mm for FF and 57.8 mm for BF, accounting for 9.2%, 16.6% and 10.2% of the gross rainfall, respectively, in the measuring period. There was the highest average monthly Er and percentage of E to gross rainfall for FF compared with SF and BF.Mean Er was 0.097 mm h^-1 (ranging from 0.028 to0.487 mm h^-1), 0.242 mm h^-1 (from 0.068 to 0.711 mm h^-1) and 0.149 mm h^-1 (from 0.060 to 0.576 mm h^-1) for SF, FF and BF, respectively. The highest average monthly Er occurred in June was 0.120 mm h^-1 for SF, 0.317 mm h^-1for FF and 0.169 mm h^-1 for BF, and the lowest value in October was 0.083 mm h^-1 for SF, 0.187 mm h^-1 for FF and 0.101 mm h^-1 for BF, respectively. The averages of Er from 8:00 to16:00 were significantly higher than those from 0:00 to 8:00 and from 16:00 to 0:00 for the three stands. The marked daily and monthly differences of Er were contributable to the variations of solar radiation, air temperature and relative humidity above the canopy.     

The impact of landslides and salt weathering on Roman structures at high latitudes—Conway Castle, Great Britain: a case study

Conway Castle is an immense historical structure, dating back to 1289 AC. It was built on highly dipping thickbeds of indurated shale (argillite) and sandstone. It is surrounded by Conway Bay, railway lines, and tall dense forests indicating high relative humidity and rainfall in this coastal area. The castle suffers from weathering noted as honeycomb, black crust, exfoliation, and discoloration with white salt efflorescence at some parts; these are diagnostic features for salt weathering as confirmed by the laboratory investigations using scanning electron microscopy, X-ray diffraction (XRD), point XRD, and hydrochemical analysis. The salt is found to be from three sources, namely, water spray from Conway Bay that is part of the Irish Sea, chemical alteration of the mortars carbonate content into sulfate salts by acid rain, and wet deposition of air pollutants on the surface of the stone. The cracks noted in the southwestern tower of this castle are a result of landslides in this area that resulted from three factors: (a) high dip angle of the indurated sandstone and shale thickbeds (about 60–65° to the south) under this castle, (b) undercutting of these beds in the dip direction by the surface water of Conway Bay, and (c) seismic waves generated by the trains passing close to this castle. All these factors result in land sliding even at a low rate; however, the net result is cracks in the tower close to these factors.     

Fault induced permanent ground deformations—an experimental comparison of wet and dry soil and implications for buried structures

Fault surface ruptures constitute a great risk to human lives, buildings and infrastructure. Despite this few building codes contain risk reducing provisions. Experiments provided results for establishing design rules in terms of possible dislocation and failure strains. Dry and wet soil behave substantially different. A brief discussion on counteracting effects of the wet soil on the interaction between a buried structure and the surrounding ground is included.     

华东典型地区大气硫沉降通量的观测和模拟研究

本文使用中国科学院常熟和鹰潭生态实验站和气象站的观测资料，应用区域酸沉降模式系统（RegADMS）和大叶阻力相似模型来研究华东地区不同下垫面条件上的大气硫沉降问题，定量估计了农田下垫面上大气硫化物的沉降通量。SO2和硫酸盐的干沉降速率使用大叶阻力相似模型来估计，使用与降水量有关的参数化方案来确定湿沉降系数。结果表明，常熟地区农田下垫面的大气硫沉降通量为19．0gm^-2 a^-1，其中干沉降占42％；而位于江西红壤地区的鹰潭站的大气硫沉降通量为10．4gm^-2a^-1，其中干沉降占83％。比较发现，两地硫干沉降通量绝对值相差不大，但其在总沉降通量中所占的份额有较大差异；常熟站的硫湿沉降通量比鹰潭站要大9．23gm^-2a^-1，该差异是由两地污染状况和气象条件的不同造成。华东地区的年硫沉降总量为1．88Mt（1Mt=10^6t），其中72．8％沉降在农田下垫面上。硫沉降中43％是干沉降，57％是湿沉降。     

膨胀岩土体湿度本构模型的探讨

水在膨胀性岩土中发挥着至关重要的作用,而膨胀岩土体中的水分分布随空间和时间而改变。文中引入折减吸力,通过分析提出膨胀屈服面的概念,并给出相应函数表达形式及硬化规律。从非饱和渗流出发,推导体积可变时的中力分布控制方程,并建立膨胀岩土体湿度应力场理论的耦合方程。     

大气降水中化学组分及其制约因素(Ⅱ)

4 讨论 4.1 相关处理 使用这种处理方法(图2)可以帮助我们对青岛等5个地区降水的化学组成受海洋和陆地     

The discrete methods for free vibration analyses of an immersed beam carrying an eccentric tip mass with rotary inertia

In this paper, a beam without contact with water is called the “dry” beam and the one in contact with water is called the “wet” beam. For a partially (or completely) immersed uniform beam carrying an eccentric tip mass possessing rotary inertia, the conventional analytical (closed-form) solution is achieved by considering the inertial forces and moments of the tip mass and rotary inertia as the boundary conditions at the tip end of the beam. However, it has been found that the approximate solution for the last problem may be achieved by two techniques: Method 1 and Method 2. In Method 1, the basic concept is the same as the conventional analytical method; but in Method 2, the tip end of the beam is considered as a free end, while the inertial forces and moments induced by the tip mass and rotary inertia are considered as the external loads applied at the tip end of the beam. The main differences between the formulation of Method 1 and that of Method 2 are: In Method 1, the “normal” shapes of the “dry” beam are functions of the frequency-dependent boundary conditions but the external loads at the tip end are equal to zero; On the contrary, in Method 2, the “normal” mode shapes of the “dry” beam are determined based on the zero boundary conditions at the tip end of the beam but the external loads at the tip end due to the inertial effects of the tip mass and rotary inertia must be taken into consideration for the free vibration analysis of the “wet” beam. Numerical results reveal that the approximate solution obtained from Method 2 are very close to that from Method 1 if the tip mass moment of inertia is negligible. Besides, the two approximate solutions are also very close to the associated analytical (closed-form) solution or the finite element solution. In general, it is hoped that there exist several methods for tackling the same problem so that one may have more choices to incorporate with the specified cases. It is believed that the two approximate methods presented in this paper will be significant from this point of view.