Hochgebirgsattraktionen aus Stahl

Mountain attractions in steel. The new steel attractions in the skiing resort of Soelden (Austria) at more than 3000 m above sea level are fetching the fascinating mountain scenario to a touchable closeness. The exceptional loading and erection conditions in the high alpine mountains in combination with the esthetical demands on the visible construction details made these touristic summit symbols to an engineering challenge.     

Temporal variations of radon concentration in the saturated soil of Alpine grassland: The role of groundwater flow

Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Frêtes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times.     

Evaluation of factors which increase corrosion around a mountain summit

Five types of thin films were exposed to the atmosphere at a mountain summit (at an elevation of about 920 m) and on a plain. Short duration exposure tests are more appropriate to measure the impact of deposition of atmospheric pollutants on surfaces than are long duration exposure tests. Short duration exposure tests using thin copper films revealed that corrosion was more intense on a mountain summit than on a nearby plain. The corrosion was mainly caused not by the deposition of particulate SO₄²⁻, but rather by the deposition of NO₃⁻ ion; SO₄²⁻ hardly affected the corrosion at all. The concentrations of acidic gases and ion components of aerosols at the mountain summit were found to be less than those at the foot of the mountain. The concentrations of NH₃ at the summit were substantially lower than those on the plain. The observations of micro-corrosion morphology on the copper films, the reaction pattern on the reagent films, and the fact that NH₃ concentrations at the mountain summit were less than those on the plain suggest that part of the NO₃⁻ component deposited at the mountain summit exists as more stable acidic NO₃⁻ particles containing less salt particles than those deposited on the plain. In contrast, particulate NO₃⁻ deposited on the plain was considered to be neutralized to particles such as NH₄NO₃ and/or NaNO₃.     

Human convection flow in spaces with and without ventilation: personal exposure to floor‐released particles and cough‐released droplets

The effects of the human convective boundary layer (CBL), room airflow patterns, and their velocities on personal exposure are examined. Two pollutants are studied which simulate particles released from the feet and generated at distances of 2 and 3 m by a human cough. A thermal manikin whose body shape, size, and surface temperatures correspond to those of an average person is used to simulate the CBL. The findings of the study reveal that for accurate predictions of personal exposure, the CBL needs to be considered, as it can transport the pollution around the human body. The best way to control and reduce personal exposure when the pollution originates at the feet is to employ transverse flow from in front and from the side, relative to the exposed occupant. The flow from the above opposing the CBL create the most unfavorable velocity field that can increase personal exposure by 85%, which demonstrates a nonlinear dependence between the supplied flow rate and personal exposure. In the current ventilation design, it is commonly accepted that an increased amount of air supplied to the rooms reduces the exposure. The results of this study suggest that the understanding of air patterns should be prioritized.     

An experimental investigation of subsurface ground temperature in Texas: a complete study

This paper describes the results of experimental studies conducted in Houston, Texas from June 1997 to May 1998 to determine seasonal variations of subsurface ground temperature. The results indicate that the average ambient temperature is 89.31°F (31.84°C) in summer (June–October), and 63.93°F (17.74°C) in winter (November–February). The ground temperature at depths greater than 10 feet remains relatively constant through the year. At a depth of 10 feet (3.04 m), the average ground temperature is 75.12°F (23.96°C) in summer and 75.87°F (24.37°C) in winter. The observed temperature differential between the ambient and the ground temperature at 10 feet is 8–17°F (4.4–9.4°C). The temperature differential suggests that there is potential for pre-heating and pre-cooling the ambient air used in conditioning commercial and institutional buildings. The least square fit equations to project average monthly subsurface ground temperatures are presented.     

“中国制造”履带起重机登顶之路

2011年5月28日、29日,中联重科和三一重工接连推出了起重能力超过3000吨级的履带起重机——中联ZCC3200NP和三一SCC86000TM,标志着＂中国制造＂的履带起重机在起重能力上已登上了全球业界的巅峰。     

太阳信托广场

Architectural ConceptSunTrust Plaza is sited in downtown Atlanta on an oblong triangular parcel that is oblique in section. The southern point of the site is a full story above the northern point, sloping gently with the contour of Peachtree Street - the primary spine of the Atlanta CBD. The building is comprised of over 1.16 million square feet of leasable office space and houses a host of systems: mechanical, conveying, electrical, security, and so on that are required to meet the needs …     

顶管技术在老城区改造中的应用实例

本文就顶管施工工艺在老城区改造中的应用作了简要阐述,采用顶管施工可以将作业面移入地下,从而避免了对地面交通的影响。     

Limited-water-supply sprinklers for manufactured (mobile) homes

A prototype limited-water-supply (LWS) sprinkler has been developed for manufactured (mobile) homes in a research program sponsored by the United States Fire Administration. The LWS sprinkler is designed to be installed at a 2.44 m (8-foot) spacing and to have a total water supply of 380 (100 gallons). The installation spacing was determined in a series of freeburn fire tests that indicated that the heat release rate at sprinkler actuation could be halved by reducing the sprinkler spacing from 3.66 m to 2.44 m (12 feet to 8 feet). A series of eight fullscale fire tests, including a corner living room scenario similar to that used in the Los Angeles Residential Test Program, was conducted to evaluate the performance of the prototype sprinkler. In five of the tests, room tenability was maintained during the 10-minute period following the actuation of a single sprinkler at a flow rate of 38 pm (10 gpm). In three tests, tenability was maintained with multiple sprinkler actuation (2 or 3 sprinklers) and a total system flow rate of 49 pm (13 gpm). The spray of the sprinkler was characterized in terms of its water flux distribution and drop size distribution. The thermal sensitivity requirements of the sprinkler are to be based upon RTI, C, and temperature rating, which would ensure that sprinkler actuation would occur at fire sizes comparable to those encountered using the prototype LWS sprinkler in this study.     

扁工作室

扁工作室是一个坐落在福戈岛东端的白色尖角形体,栖止在沿海岸线的岩石地带。工作室正门极富对比色彩,因其最南端高于地面6.1m(20英尺),工作室紧凑的梯形平面,因其东西两面的外墙的延展而加大,在南面形成了一个掩蔽的三角形入口平台,在北面则是俯瞰大洋的露台。