长大区间隧道抽出式串联通风机排烟能力实验研究

为实现有效通风以降低隧道火灾带来的损失和伤亡,依托青岛市地铁8号线大洋站至青岛北站区间隧道,建立线性比尺为1∶15的隧道通风排烟模型实验系统,针对通风机串联单抽,围绕3种通风机频率匹配组合,测定单机的变频频率值、电功消耗、排烟道与行车道的断面平均风速以及右侧行车道静压。研究结果表明：在相同功率消耗下,不同频率匹配的串联通风机排烟效果存在差异;针对此差异,利用气体挡烟墙性能及其计算欧拉数值比较发现,风井近端的通风机频率较大时,下游对污染气流的抵抗力更强,拥有更好的排烟效果。研究结果可为隧道火灾提供更有效率的防灾救灾数据支持,并从欧拉数方面为研究隧道临界风速提供新角度。     

The English football ground as a representation of home

Home refers to a number of locations and various meanings associated with it have been identified. However, research has been limited by a focus on house and traditional family. To expand our understanding, this study explored whether a secondary space, the English professional football ground, embodied the same meanings as other places called home. Web survey respondents confirmed, to some extent, their preferred football team's home stadium does represent home similarly. Three distinct aspects of the home emerged: general qualities of home, place attachment, and the importance of social interactions. Some aspects varied by length of team occupancy and season ticket holder status; but none differed by gender. Though the football stadium does represent some qualities of home, it was speculated this may be due to the unique connection to place that underlies English football. Future research should explore how the views of stadiums and other public spaces as home places vary across locales in order to identify how home differs from places to which we are attached.     

ERODIBILITY OF URBAN BEDROCK AND ALLUVIAL CHANNELS,NORTH TEXAS1

ABSTRACT: Major erosion of urban stream channels is found in smaller basins in the North Texas study area with contributing drainage areas of less than ten square miles. Within these basins, four basic channel types are identified based on bed and bank lithologies: alluvial banks and bottoms, alluvial banks and gravel bottoms, alluvial banks with rock bottoms, and rock banks with rock bottoms. Most channels (75 percent) have alluvial banks with gravel or rock bottoms. Channel slopes are steep (.38 to.76 percent). Rock consists predominantly of shale and limestone. Channel cross sections are divided into the following four zones based on weathering, scour and entrainment mechanisms: soil zone, slake zone, rock zone and bed material zone. Erodibility of the channels is determined using multiple techniques including reach hydraulics and stream power computations, submerged jet testing, slab entrainment thresholds, and slake durability rates. Procedures are based on both empirical and modeled time series estimates of channel erosion. Field and modeled results support rates of erosion of up to four inches per year. Rates are tied to flow regime, climate, and type of channel bed and banks.     

Assessment of Soil Cover Degradation and Desertification in Northern Lowland Dagestan

New principles of the assessment of soil cover degradation and desertification, the scale and intensity of destructive processes manifestation are determined.     

RIPARIAN FOREST EFFECT ON LATERAL STREAM CHANNEL MIGRATION IN THE GLACIAL TILL PLAINS1

ABSTRACT: Dendrochronology analyses of point bar complexes were used to quantify the effects of riparian forests on local lateral migration of bends in seven streams in the glacial till plains of north central Missouri. Stream bends were paired with similar bank height, midchannel radius of curvature, soil composition, and watershed size. In each pair, one concave bank was forested and one was unforested. Stream bends with unforested concave banks had an average local migration rate three times greater than stream bends that had forested concave banks.     

安徽淮北平原地下水动态变化研究

论文对安徽淮北地区69个地下水位站的1980-2006年平均地下水埋深资料进行分析,得出淮北地区多年平均地下水埋深2.33m,1980-1990年各地下水年均埋深较浅、变幅较小,1990年以后地下水埋深变幅加大,且埋深有明显的加深趋势。研究认为淮北平原地下水动态虽然受降水量、蒸发量和人类活动等多种因素影响,但近些年来地下水的动态变化主要是人类活动影响的结果。这些人类活动包括地下水资源开发利用、土地利用、水利工程、农业节水灌溉措施等。其中过度开发利用地下水是导致安徽淮北平原地下水埋深下降,地下水资源减少的主要原因。适度开发利用地下水有利于淮北地区地下水的循环更新,但过度的开发利用,已造成平原北部开始出现严重的环境地质问题,应限制开采。     

FLOOD HAZARD IDENTIFICATION AND FLOOD PLAIN MANAGEMENT ON ALLUVIAL FANS1

ABSTRACT: Recognition of the flood hazard that exists on alluvial fans has seriously lagged behind the recognition of other more conventional flood hazards such as those associated with most rivers. This delay in recognition was due, until recently, to a general lack of economic investment and development in these areas and a concomitant lack of historical alluvial fan flood damage. Dramatic recent events, such as Tropical Storm Kathleen, emphasized to the Federal Insurance Administration (FIA) the need for developing an appropriate methodology to identify flood hazard areas on alluvial fans. This paper presents the methodology now employed by FIA as well as flood plain management considerations that could reduce future flood related damage to communities developing in these areas.     

LEAKY ACRES RECHARGE FACILITY: A TEN-YEAR EVALUATION1

From 1971-1980, studies were conducted at Fresno, California, to identify and quantify, where possible, the soil and water chemistry, subsurface geologic, hydrologic, biologic, and operational factors that determine the long term (10-year) effectiveness of basin type artificial ground water recharge through alluvial soils. This paper updates previous findings and refers to publications that describe the geology beneath the basins and regional geology that determine the transmission and storage properties for local ground water management and chemical quality enhancement. High quality irrigation water from the Kings River was used for recharge. Construction and land costs for the present expanded facility 83 ha (205.2 ac) using three parcels of land were $1,457,100. The nine-year annual mean costs for only canal water, maintenance, and operation were $110.42/ha·m ($13.62/ac·ft) based on an average recharge rate of 1338 ha·m/yr (10,848 ac·ft/yr) at 86 percent facility efficiency. The measured end of season recharge rate averaged 14.97 ± 0.24 cm/day. The 10-year mean actual recharge rate based on actual water delivered, total ponded area, and total days of recharge was 12.1 cm/day.     

EVALUATION OF A STREAM AQUIFER ANALYSIS TEST USING ANALYTICAL SOLUTIONS AND FIELD DATA1

ABSTRACT: Considerable advancements have been made in the development of analytical solutions for predicting the effects of pumping wells on adjacent streams and rivers. However, these solutions have not been sufficiently evaluated against field data. The objective of this research is to evaluate the predictive performance of recently proposed analytical solutions for unsteady stream depletion using field data collected during a stream/aquifer analysis test at the Tamarack State Wildlife Area in eastern Colorado. Two primary stream/aquifer interactions exist at the Tamarack site: (1) between the South Platte River and the alluvial aquifer and (2) between a backwater stream and the alluvial aquifer. A pumping test is performed next to the backwater stream channel. Drawdown measured in observation wells is matched to predictions by recently proposed analytical solutions to derive estimates of aquifer and streambed parameters. These estimates are compared to documented aquifer properties and field measured streambed conductivity. The analytical solutions are capable of estimating reasonable values of both aquifer and streambed parameters with one solution capable of simultaneously estimating delayed aquifer yield and stream flow recharge. However, for long term water management, it is reasonable to use simplified analytical solutions not concerned with early‐time delayed yield effects. For this site, changes in the water level in the stream during the test and a varying water level profile at the beginning of the pumping test influence the application of the analytical solutions.     

INFLUENCES OF INCREASED SAND DELIVERY ON THE MORPHOLOGY OF SAND AND GRAVEL CHANNELS1

ABSTRACT A flume study was conducted to examine (1)changes in the particle-size distribution of sediments in riffles due to the proportion of sand in transport and the total rate of bedload transport at the time the riffle is deposited and (2) the effect of high sand transport rates on the stability of gravel riffles. The median particle size of sediment deposited in the riffle was larger than that of the sediment in transport. Small but significant (a = 0.05) decreases in the median particle size of riffle sediments resulted as the sand-to-gravel ratio. Increased concentrations of sand in transport caused previously stable gravel riffles to undergo scour. These results, in combination with information from other studies, suggest that an alluvial channel with pool-riffle sequences and with sand and gravel beds may respond to an increased delivery of sand by reducing form roughness. Form roughness can be reduced by degrading riffles and filling pools. Subsequent responses may be increases in width-to-depth ratio and slope.