Concurrent concentration declines in groundwater-dissolved radon,methane and ethane precursory to 2011 MW 5.0 Chimei earthquake

Radon volatilization mechanism into the gas phase was hypothesized to explain the anomalous declines in groundwater radon precursory to three major earthquakes – (1) 2003 M_W = 6.8 Chengkung, (2) 2006 M_W = 6.1 Taitung, and (3) 2008 M_W = 5.4 Antung in Taiwan. The epicenters were located 24 km, 52 km, and 13 km from the Antung radon-monitoring well D1, respectively. To verify the mechanism of in situ volatilization, we monitored groundwater-dissolved ethane in addition to radon and methane at well D1 in the Antung hot spring since November 30, 2010. The mechanism of in situ radon volatilization has been corroborated by the simultaneous concentration declines in groundwater-dissolved radon, methane, and ethane precursory to the 2011 M_W 5.0 Chimei earthquake. The epicenter was located 32 km from the Antung radon-monitoring well D1. Observations at the Antung hot spring also suggest that radon is the best-choice tracer among the groundwater-dissolved gases for strain changes in the crust preceding an earthquake. On the southern segment of the Chihshang fault, the observed radon minima decrease as the earthquake magnitude increases.     

Spatial variations of radon and helium concentrations in soil-gas across the Shan-Chiao fault, Northern Taiwan

Spatial variability of gases like radon and helium in soil-gas can be used for seismic surveillance and for finding fault system. The present study is aimed at determining a possible connection between eventual radon/helium anomalies and active fault. Radon and helium concentrations in subsurface soil-gas have been monitored along the Shan-Chiao fault, Northern Taiwan. Twenty transverse profile surveys have been conducted across the fault, where 235 and 125 samples were collected for helium and radon analyses, respectively. The data analysis clearly reveals anomalous values of both radon and helium along the fault. To find the fault system, where the migration of gases is governed by advection, it is essential to identify the anomalies in both radon and helium together. The consistency of this pattern confirms that radon and helium together can act as a powerful tool for the detection and mapping of active fault zones.     

Analysis of seasonal variation of indoor radon concentration in Tehri Garhwal, Northern India

The seasonal variation analysis of indoor radon has been carried out in the hilly region of Tehri Garhwal, Northern India by using LR-115 Type II, plastic track detector. In the analysis the winter/summer ratio radon values were found to vary from 0.63 to 1.64 and 1.02 to 1.22 for cemented houses and mud houses, respectively. Over all the average value of winter/summer ratio was found maximum in both cemented and mud houses respectively.      

Relationships between radon anomalies and seismic parameters in N-W Himalaya, India

Radon data accumulated during 1992–1999 in the grid (30–34°N, 74–78°E) in N-W Himalaya have been anlaysed vis a vis seismic data recorded in the same area, supplied by Indian Meteorological Department (IMD) network. In general, there is a positive correlation between the total radon emission and the microseismicity in the area under investigation. The earthquake magnitude has moderate positive correlation with epicentral distance and low positive correlation with amplitude of radon precursory signal, whereas both show low negative correlation between them.

Empirical scaling relations are proposed using the best fit straight line from the log-linear graphs between magnitude of the events and log of the product of amplitude of radon anomaly and epicentral distance. The error between the recorded and calculated magnitude is also taken into account. The error range is higher at lower epicentral distances and magnitudes, showing that the local geology and tectonics have predominant influence on radon signals.     

Baseline studies of radon/thoron concentration levels in and around the Lambapur and Peddagattu areas in Nalgonda district, Andhra Pradesh, India

Studies conducted by Atomic Minerals Directorate of Exploration and Research (AMD) of Hyderabad, India had established the presence of higher concentrations of uranium in Lambapur and Peddagattu areas of Nalgonda district, AP, India and it was estimated that it could be a viable source for commercial extraction. The envisaged extraction process involves dispersion of radioactive particulate matter into atmosphere. Environmental radioactive studies in and around proposed mining areas at this point of time will be extremely useful for establishing base line data before a large scale uranium extraction process comes into existence. To this end, Solid State Nuclear Track Detectors were installed to evaluate indoor radon and thoron concentration levels in the dwellings of the area. The geometric means of radon and thoron concentration levels were found to be (7.1±0.2)×10¹ and (6.7±0.3)×10¹ Bq/m³, respectively. Simultaneously, natural background radiation measurements were also made and these levels are found to vary from 770 to 3995 μGy/y in the spatial distribution.     

Study of indoor radon and thoron progeny levels in surrounding areas of Nalbari, Assam, India

With the growing understanding of the role of radon and its daughter products as major sources of radiation exposure, the importance of large number of estimation of radon concentration in various parts of the country is realized. Inhalation of radon, thoron and their decay products is the major source of the total radioactive dose received by the human population from natural radiation. The indoor radon and thoron progeny levels in Nalbari area of Assam are studied by using the LR-115 (type II) Solid State Nuclear Track Detector in Plastic Twin Chamber dosimeter. Radon and thoron progeny levels in different types of dwellings for one full calendar year are presented in this paper. For Assam Type (A.T.) houses, indoor radon progeny concentrations vary from 0.17 to 0.64 mWL with an annual geometric mean of 0.27 mWL and that for Reinforced Cement Concrete (R.C.C.) houses vary from 0.22 mWL to 0.60 mWL with the annual geometric mean of 0.37 mWL. The thoron progeny levels in A.T. houses also vary from 0.01 to of 0.05 mWL with an annual geometric mean of 0.02 mWL and that for R.C.C. houses vary from 0.02 to 0.08 mWL with the annual geometric mean of 0.04 mWL.      

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介绍了拟建的高温高压氦气实验回路的主要目标、特征以及回路中各设备的性能、参数,应用RELAP5程序完成了回路的热工设计分析,CAESAR程序优化了管路和设备的布置及应力分析,结果表明设计具备工程可行性。     

A comparative study of indoor radon level measurements in the dwellings of Punjab and Himachal Pradesh, India

The LR-115 type-II plastic track detector has been used for measuring the indoor radon levels in the dwellings of some villages of Punjab and Himachal Pradesh. In Punjab, the villages surveyed are Rampura Phul, Lehra Mahabat and Pitho (villages in Bathinda district), and Amritsar city. The average indoor radon levels in these areas are found to vary from 64 to 152 Bq/m³, which are quite within the safe limits recommended by International Commission on Radiological Protection (Ann. ICRP 23(2)). The indoor radon levels have also been measured in the dwellings of Hamirpur district of Himachal Pradesh. The villages surveyed in this area are Nukhel, Badarn, Galore-Khas, Har-Upper, Tikker Brahamana and Awah-Lower where radon concentration has been found to vary from 261 to 724 Bq/m³. These values are higher than the recommended limit.     

Preliminary Conceptual Design of Helium Experimental Loop

For the qualification of TBM design, it is indispensable to test mock-ups in a helium loop under realistic pressure and temperature profiles. The main characteristics of the loop and preliminary conceptual design are described in the paper.     

中国氦冷固态实验包层氦气实验回路设计分析

介绍了拟建的高温高压氦气实验回路的主要目标、特征以及回路中各设备的性能、参数,应用RELAP5程序完成了回路的热工设计分析,CAESAR程序优化了管路和设备的布置及应力分析,结果表明设计具备工程可行性。     

DY-60氦气压缩机研制

详细描述了一种大功率、大排气量氦气压缩机的研制过程。给出了该压缩机的主要技术指标 ,阐述了系统流程和工程原理。并对冷却器、纯化器、滤油器等主要部件的设计、结构及组成进行了较为详细的描述。最后描述了控制系统作用、原理及组成的部件。     

氦的化合物和α粒子的固化

就宇宙而言,氦不是稀有气体,同样,也非惰性气体,因为氦可以与其它元素生成化合物._(94)~(239)Pu衰变而发射口粒子,俘获电子而变为氦气,导致钚体积年增加6.8%,损害钚晶格.所谓"固化口粒子",即使α粒子与其它原子生成固态离子化合物,最有希望的生成碳或铝的氯化合物.可以基本消除氦泡的影响.这是举世瞩目的.     

氦的化合物和粒子的固化

就宇宙而言,氦不是稀有气体,同样,也非惰性气体,因为氦可以与其它元素生成化合物. 衰变而发射 粒子, 俘获电子而变为氦气 ,导致钚体积年增加6.8% ,损害钚晶格.所谓”固化 粒子”, 即使 粒子与其它原子生成固态离子化合物, 最有希望的生成碳或铝的氦化合物.可以基本消除氦泡的影响.这是举世瞩目的.     

Exhalation rate study of radon/thoron in some building materials

Indoor radon/thoron have been recognised as one of the health hazards for mankind. Common building materials used for construction of houses, which are considered as major sources of these gases in indoor environment, have been studied for exhalation rate of radon/thoron. ‘Can’ technique using plastic track detector LR-115 type-II has been used for measurement. Exhalation rates for radon and thoron have been found to be varying from a minimum value of 0.024 and 29.4 Bqm⁻² h⁻¹ for cement plastered brick to a maximum value of 0.16 and 692.2 Bqm⁻² h⁻¹ for unfired brick, respectively. Exhalation rate for thoron has been found to be several times higher than that for radon. Measured exhalation rates for thoron indicate significant presence of thoron in indoor environment which is also supported by indoor measurements of thoron and its progeny.     

Study of uranium, radium and radon exhalation rate in soil samples from some areas of Kangra district, Himachal Pradesh, India using solid-state nuclear track detectors

LR-115 plastic track detectors have been used for the measurement of radon exhalation rate and radium concentration in soil samples collected from some villages of Kangra district, Himachal Pradesh, India. Uranium concentration has also been determined in these soil samples using fission track technique. Radium concentration in soil samples has been found to vary from 11.54 to 26.71 BqKg⁻¹, whereas uranium concentration varies from 0.75 to 2.06 ppm. The radon exhalation rate in these samples has been found to vary from 15.16 to 35.11 mBqKg⁻¹ h⁻¹ (502.12 to 1162.64 mBqm⁻² h⁻¹).     

Measurement of radon emanation in construction materials

Due to the new proposed Israeli approach for radioactivity in construction materials (IS 5098) issued in 2007, the radon emanation of a construction material, a brick in the form of a box (a rectangular parallelepiped), should be checked when its four faces are insulated in order to achieve the same simulation effect when a concrete block is embedded into a wall. A physical model was developed in order to measure the insulation level (quality) of a building product (bulk concrete, building block, tiles, etc.) when its four sides are insulated by various materials. Under the experimental conditions it was found that the insulation level for bulk concrete was 99.5 ± 0.04% which is in good agreement with the requirement of the new Israeli Standard IS 5098. The influence of aging of concrete materials on radon emanation and the emanation ratio, deduced from measurements of insulated and non-insulated materials, was investigated.     

Design, construct and test of a calibration radon chamber

A new radon chamber has been designed, constructed, and tested. The design was chosen to meet the needs of several different radon detection techniques, both active and passive. The chamber is a cubic shape made of pixy glass with volume about . On top, it has a circular opening with double lock system for entering and removing samples without significant disturbance of the inside concentration. It also has the possibility to expose passive radon detectors at different levels inside the chamber. In addition, two fans, with variable speeds, were fitted in two opposite corners to maintain the uniformity of radon gas inside the volume. This calibration chamber can be used to perform researches and studies on radon behavior, in addition to calibrating different types of detectors (passive and active) which are used for measuring radon and its daughters. Solid radium-226 source with activity of 122 kBq was placed at the bottom of the chamber to generate radon.     

氦原子基态能量的组态相互作用计算

将基态氦原子的波函数取作1s2和1s2s两个组态函数的叠加,利用组态相互作用方法解析计算了氦原子基态的非相对论能量.计算结果表明,考虑激发态1s2s与基态的相互作用,可以获得0.029 38Hartree的基态能量修正.本文的解析组态相互作用方法可作为量子力学教学的有益补充.     

震前兆信息传播、分布及其探测原理

地壳岩石层由板块、断层和其间的断层泥构成,在研究地震前兆信息传播这类准静力学问题时,应将其作为大尺度离散态颗粒物质体系处理.地震孕育过程中,在大地构造力驱动下,岩石层块克服所受摩擦力和边界断层泥阻力发生滞滑移动.当岩块间断层泥受挤压后其强度增大到一定程度时,又推动下一岩石层块滞滑移动,就这样渐次使其他岩石层块发生移动,并以力链形式分布和传递.文章给出了此模型的物理依据和实际观测例证;通过模拟实验和分析阐述了力-移动-形变在地层中分布的表达形式和传播时间序;说明了地震前兆信息的主要特征及其与地震发生之间的关联,以及探测有效地震前兆信息的方法原理.同时,论述了用颗粒物理原理与连续介质观念对地震前兆认识的本质区别,解释了连续介质观点难以理解的若干地震学问题. 关键词： 地震前兆 颗粒物质 滞滑移动 力链     

Influences on indoor radon concentrations in Riyadh,Saudi Arabia

The influences on indoor radon concentrations in Riyadh, Saudi Arabia survey was carried out for 786 dwellings. The measurements were obtained by using a passive integrating ionization system with an E-Perm^® Electret ion chamber. Radon levels ranged from 1 to 195 Bq m⁻³, with a mean value of 24.68 Bq m⁻³, the geometric mean and the geometric standard deviation are 21 and 2 respectively. 98.5% of the results were below the action level recommended by WHO of 100 Bq.m⁻³. The results were found to vary substantially due to types of houses and rooms, ventilation, seasons and building materials. Radon concentrations were higher in houses with no ventilation systems, and central air conditioners, and were relatively lower in well ventilated houses with red bricks and water air conditioners.