Measurement of radon exhalation rate in various building materials and soil samples

Indoor radon is considered as one of the potential dangerous radioactive elements. Common building materials and soil are the major source of this radon gas in the indoor environment. In the present study, the measurement of radon exhalation rate in the soil and building material samples of Una and Hamirpur districts of Himachal Pradesh has been done with solid state alpha track detectors, LR-115 type-II plastic track detectors. The radon exhalation rate for the soil samples varies from 39.1 to 91.2 mBq kg^?1 h^?1 with a mean value 59.7 mBq kg^?1 h^?1. Also the radium concentration of the studied area is found and it varies from 30.6 to 51.9 Bq kg^?1 with a mean value 41.6 Bq kg^?1. The exhalation rate for the building material samples varies from 40.72 (sandstone) to 81.40 mBq kg^?1 h^?1 (granite) with a mean value of 59.94 mBq kg^?1 h^?1.     

聊城市地下水开采和补源的研究分析

地下水是聊城市重要的而且是主要的水资源,近年来,地下水的开采和补源引起了人们的广泛关注.本文拟对地下淡水资源的时空分布、运动规律、地下水资源计算和评价及聊城市地下水开发利用问题进行一些探讨,对于引黄(河)灌区合理引用黄河水和开采地下水具有重要的指导作用和应用价值.     

Numerical simulation of migration–accumulation of oil resources

Numerical simulation of oil migration and accumulation is to describe the history of oil migration and accumulation in basin evolution. It is of great value to the evaluation of oil resources and to the determination of the location and amount of oil deposits. This thesis discusses the characteristics of petroleum geology and permeation fluid mechanics. For the three-dimensional problems of Dongying hollow of Shengli Petroleum Oil Field, it puts forward a new model and a kind of modified method of upwind finite difference fractional steps implicit interactive scheme. For the famous hydraulic experiment of secondary migration–accumulation, the numerical simulation test has been done, and both the computational and experimental results are basically identical. For the actual problem of Dongying hollow, the numerical simulation test and the actual conditions are basically coincident. Thus, the well-known problem has been solved.     

Oxidation of the Kaapvaal lithospheric mantle driven by metasomatism

The oxidation state, reflected in the oxygen fugacity (fO₂), of the subcratonic lithospheric mantle is laterally and vertically heterogeneous. In the garnet stability field, the Kaapvaal lithospheric mantle becomes progressively more reducing with increasing depth from Δlog fO₂ FMQ-2 at 110 km to FMQ-4 at 210 km. Oxidation accompanying metasomatism has obscured this crystal-chemical controlled depth-fO₂ trend in the mantle beneath Kimberley, South Africa. Chondrite normalized REE patterns for garnets, preserve evidence of a range in metasomatic enrichment from mild metasomatism in harzburgites to extensive metasomatism by LREE-enriched fluids and melts with fairly unfractionated LREE/HREE ratios in phlogopite-bearing lherzolites. The metasomatized xenoliths record redox conditions extending up to Δlog fO₂ = FMQ, sufficiently oxidized that magnesite would be the stable host of carbon in the most metasomatized samples. The most oxidized lherzolites, those in or near the carbonate stability field, have the greatest modal abundance of phlogopite and clinopyroxene. Clinopyroxene is modally less abundant or absent in the most reduced peridotite samples. The infiltration of metasomatic fluids/melts into diamondiferous lithospheric mantle beneath the Kaapvaal craton converted reduced, anhydrous harzburgite into variably oxidized phlogopite-bearing lherzolite. Locally, portions of the lithospheric mantle were metasomatized and oxidized to an extent that conversion of diamond into carbonate should have occurred. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The Decline and Restoration of a Coastal Lagoon (Lake Veere) in the Dutch Delta

The former tidal inlet Lake Veere was turned into a stagnant brackish lake in 1961. Ever since, the system has shown a continuous degradation. The current study shows the monitoring results for the macrozoobenthic communities and the abiotic conditions for the period 1990–2008. This includes the first step to remediation, the restoration of the exchange between the tidal marine Eastern Scheldt and Lake Veere in 2004. A continuous decline in water clearance co-occurring with decreasing macrofauna densities and richness was observed till 2004. Water quality (e.g., secchi depth, nutrient levels, and oxygen conditions) improved significantly after the measure at a higher salinity level with less variation. But the macrofauna densities, biomass, and diversity did not improve yet. First indications of changes in the benthic communities by arrival of new and returning species are however observed and show that restoration at macrofauna level follows the improved abiotic conditions with a delay of several years.     

Eoalpine tectonics of the Eastern Alps: implications from the evolution of monometamorphic Austroalpine units (Schneeberg and Radenthein Complex)

Monometamorphic metasediments of Paleozoic or Mesozoic age constituting Schneeberg and Radenthein Complex experienced coherent deformation and metamorphism during Late Cretaceous times. Both complexes are part of the Eoalpine high-pressure wedge that formed an intracontinental suture and occur between the polymetamorphosed Ötztal–Bundschuh nappe system on top and the Texel–Millstatt Complex below. During Eoalpine orogeny Schneeberg and Radenthein Complexes were south-dipping and they experienced a common tectonometamorphic history from ca. 115 Ma onwards until unroofing of the Tauern Window in Miocene times. This evolution is subdivided into four distinct tectonometamorphic phases. Deformation stage D1 is characterized by WNW-directed shearing at high temperature conditions (550–600°C) and related to the initial exhumation of the high-pressure wedge. D2 and D3 are largely coaxial and evolved during high- to medium-temperature conditions (ca. 450 to ≥550°C). These stages are related to advanced exhumation and associated with large-scale folding of the high-pressure wedge including the Ötztal-Bundschuh nappe system above and the Texel–Millstatt Complex below. For the area west of the Tauern Window, F2/F3 fold interference results in the formation of large-scale sheath-folds in the frontal part of the nappe stack (formerly called “Schlingentektonik” by previous authors). Earlier thrusts were reactivated during Late Cretaceous normal faulting at the base of the Ötztal–Bundschuh nappe system and its cover. Deformation stage D4 is of Oligo-Miocene age and accounted for tilting of individual basement blocks along large-scale strike-slip shear zones. This tilting phase resulted from indentation of the Southern Alps accompanied by the formation of the Tauern Window.     

三峡库区气温变化高精度区域气候模式模拟与预估

基于三峡库区1961—2005年气温逐日格点数据,评估由BCC_CSM1.1模式驱动的RegCM4区域气候模式、MPI-ESM-LR模式驱动的CCLM区域气候模式对三峡库区平均气温、极端高温的模拟能力,选用与观测值更为接近的区域气候模式模拟结果,预估三峡库区在RCP4.5温室气体排放情景下2016—2035年气温变化。结果表明:RegCM4和CCLM模式均能模拟出三峡库区多年平均气温、高温日数和高温强度的季节变化和空间分布形态,但均在库区东北部模拟的年平均气温偏低、高温日数偏少、高温强度偏小。同时,模式均能较好地反映出三峡库区年平均气温、年高温日数的年际变化,但对高温强度的年际变化模拟较差。总体而言,CCLM模式对三峡库区气温的模拟效果好于RegCM4。RCP4.5情景下,三峡库区2016—2035年平均气温、高温日数比当代(1986—2005年)分别增加0.6℃和5d,高温强度变化不明显。     

Frequency-dependent rupture process,stress change,and seismogenic mechanism of the 25 April 2015 Nepal Gorkha <Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> 7.8 earthquake

On 25 April 2015, an M _w 7.8 earthquake occurred on the Main Himalaya Thrust fault with a dip angle of ~ 7° about 77 km northwest of Kathmandu, Nepal. This Nepal Gorkha event is the largest one on the Himalayan thrust belt since 1950. Here we use the compressive sensing method in the frequency domain to track the seismic radiation and rupture process of this event using teleseismic P waves recorded by array stations in North America. We also compute the distribution of static shear stress changes on the fault plane from a coseismic slip model. Our results indicate a dominant east-southeastward unilateral rupture process from the epicenter with an average rupture speed of ~3 km s^?1. Coseismic radiation of this earthquake shows clear frequency-dependent features. The lower frequency (0.05–0.3 Hz) radiation mainly originates from large coseismic slip regions with negative coseismic shear stress changes. In comparison, higher frequency (0.3–0.6 Hz) radiation appears to be from the down-dip part around the margin of large slip areas, which has been loaded and presents positive coseismic shear stress changes. We propose an asperity model to interpret this Nepal earthquake sequence and compare the frequency-dependent coseismic radiation with that in subduction zones. Such frequency-dependent radiation indicates the depth-varying frictional properties on the plate interface of the Nepal section in the main Himalaya thrust system, similar to previous findings in oceanic subduction zones. Our findings provide further evidence of the spatial correlation between changes of static stress status on the fault plane and the observed frequency-dependent coseismic radiation during large earthquakes. Our results show that the frequency-dependent coseismic radiation is not only found for megathrust earthquakes in the oceanic subduction environment, but also holds true for thrust events in the continental collision zone.     

Features of the Extremely Severe Drought in the East of Southwest China and Anomalies of Atmospheric Circulation in Summer 2006

The spatial-temporal features of the extremely severe drought and the anomalous atmospheric circulation in summer 2006 are analyzed based on the NCEP/NCAR reanalysis data, the characteristic circulation indices given by the National Climate Center of China, and the daily precipitation data of 20 stations in the east of Southwest China (ESC) from 1959 to 2006. The results show that the rainless period started from early June and ended in early September 2006 with a total of more than 80 days, and the rainfall was especially scarce from around 25 July to 5 September 2006. Precipitation for each month was less than normal, and analysis of the precipitation indices shows that the summer precipitation in 2006 was the least since 1959. The extremely severe drought in the ESC in summer 2006 was closely related to the persistent anomalies of the atmospheric circulation in the same period, i.e., anomalies of mid-high latitude atmospheric circulation, western Pacific subtropical high (WPSH), westerlies, South Asian high, lower-level flow, water vapor transport, vertical motion, and so on. Droughts usually occur when the WPSH lies anomalously northward and westward, or anomalously weak and eastward. The extreme drought in summer 2006 was caused by the former. When the WPSH turned stronger and shifted to the north and west of its normal position, and the South Asian high was also strong and lay eastward, downdrafts prevailed over the ESC and suppressed the water vapor transfer toward this area. At the same time, the disposition of the westerlies and the mid-high latitude circulation disfavored the southward invasion of cold air, which jointly resulted in the extremely severe drought in the ESC in summer 2006. The weak heating over the Tibetan Plateau and vigorous convective activities over the Philippine area were likely responsible for the strong WPSH and its northwestward shift in summer 2006.     

Seismic behavior of self-centering reinforced concrete wall enabled by superelastic shape memory alloy bars

Reinforced concrete (RC) wall is a common type of structural component used in high-rise buildings to resist lateral loads induced by earthquakes. RC walls are typically designed and detailed to dissipate energy through significant inelastic responses to meet expected seismic performance under moderate-to-strong earthquakes. However, costly repair or even demolition caused by excessive residual deformation is usually inevitable. Given this deficiency, this study investigates the feasibility of utilizing superelastic shape memory alloy (SMA) bars to achieve self-centering (SC) RC walls. Under this condition, the residual deformation of SC–RC walls is reduced by superelastic SMA with large recoverable strain and remarkable fatigue properties. The mechanical properties of superelastic nickel–titanium bars and SC–RC wall design are described. A numerical SC–RC wall model is developed and validated by comparing the test results. Parametric studies of SC–RC wall systems are then conducted to investigate the effects of axial compressive load ratio, bottom slit length, and lower plateau stress factor of SMA. Results show that the proposed SC–RC walls have excellent SC ability and moderate energy dissipation capacity. The damage regions and levels of the SC–RC wall systems are also discussed.