Estimated Recharge Rates From Groundwater Temperatures In The Nara Basin,Japan

Groundwater recharge rates to the sandy aquifer in the Nara basin, Japan, were determined by using a theory that describes the simultaneous transfer of heat and water in a porous medium. Seasonal changes in temperatue-depth profiles were used to estimate the recharge rates in a relatively shallow aquifer. Estimations of the recharge rates were done by fitting a dimensionless parameter to the type curves developed by Taniguchi (1993) after the amplitudes of annual variations of groundwater temperatures were measured at several depths. Annual recharge rate estimated by fitting observed temperatures to the type curves was 459 mm in the Nara basin. This value agrees well with values calculated from water-balance methods and values reported in the literature. Résumé: Les taux de recharge d'un aquifère sableux dans le bassin de Nara (Japon) ont été déterminés au moyen d'un modèle qui décrit le transfert simultané de la chaleur et de l'eau en milieu poreux. Les variations saisonnières le long de profils verticaux de température sont utilisées pour estimer les taux de recharge dan un aquifère relativement superficiel. Les estimations de ces taux de recharge ont été réalisées par l'ajustement d'un paramètre sans dimension aux courbes types proposées par Taniguchi (1993) d'après les amplitudes des variations annuelles de la température de l'eau souterraine mesurée à différentes profondeurs. La recharge annuelle estimée par l'ajustement des températures observées aux courbes types est 459 mm dans le bassin de Nara. Cette valeur est en bon accord avec celles caculées à partir du bilan hydrologique et avec celles de littérature. Resumen: Las velocidades de recarga en el acuífero arenoso de la cuenca del Nara, Japón, se determinaron por medio de una teoría que describe la transferencia simultánea de calor y agua en un medio poroso. Los cambios estacionales en los perfiles temperatura-profundidad permitieron estimar las velocidades de recarga en una acuífero relativamente somero. Las estimaciones de la velocidad de recarga se hicieron por ajuste de un parámetro adimensional a las curvas-tipo desarrolladas por Taniguchi (1993). Para ello se utilizaron las amplitudes de las variaciones anuales de las temperaturas del agua a distintas profundidades. La recarga anual en la cuenca del Nara, estimada mediante este método de ajuste de curvas, fue de 459 mm. Este valor es semejante a la recarga calculada a partir de métodos de balance y a la obtenida de la bibliografía.     

Research on the seismotectonics of the Jan－uary 17，1995 Hanshin M7．2 earthquake

ＲｅｓｅａｒｃｈｏｎｔｈｅｓｅｉｓｍｏｔｅｃｔｏｎｉｃｓｏｆｔｈｅＪａｎ┐ｕａｒｙ１７，１９９５ＨａｎｓｈｉｎＭ７．２ｅａｒｔｈｑｕａｋｅＺＨＵ－ＪＵＮＨＡＮ１）（韩竹君），ＦＵ－ＨＵＲＥＮ２）（任伏虎），ＹｕｊｉｒｏＯｇａｗａ２）（小川雄二郎）ａ...     

对流层平流层气溶胶粒子的形态和化学组成

分析研究了１９９３年和１９９４年的８月、９月在香河地区上空采集的单个气溶胶粒子的形态及化学元素和化合物的组成。结果表明：１９９３年,在对流层大气中的气溶胶颗粒经常出现不规则形的粒子,可能是土壤粒子;而在平流层大气中的颗粒以具有“卫星”结构的硫酸粒子为主;硫酸铵粒子则经常出现在对流层的中、下部。香河地区上空颗粒物的化学元素组成比较复杂,单一化学元素组成的粒子较少,粒子主要含有Ｓｉ,Ｆｅ,Ａｌ和Ｓ等元素。气溶胶的化合物有硫酸盐、硅酸盐、硝酸盐和磷酸盐等     

Oxidative–reductive photodecomposition of perfluorooctanoic acid in water

This article aims to elucidate on usefulness of vacuum ultraviolet (VUV) for photoreductive degradation of perfluorooctanoic acid (PFOA), a representative perfluorinated compound (PFC), in water for the first time. Bench-scale tests were conducted on oxidative and reductive (with aquated electron: e _aq ^? ) mineralization of PFOA using low-pressure UV (LPUV) lamps and potassium iodide. Unlike with 254 nm wavelength (UVC), the reductive mineralization with VUV was very inefficient compared to the corresponding oxidative mineralization. The inefficiency is attributed to low reactivity of e _aq ^? with PFOA and its fluorinated products than that of 185 nm photons. Direct VUV photolysis of PFOA and its products in reductive reaction conditions was not apparent due to a very big difference in reactivity of 185 and 254 nm photons with iodide. The results demonstrated that highly energetic VUV photons are not suitable for photoreductive degradations of PFCs involving e _aq ^? , but they can be best used for oxidative degradations. These findings should serve as an important reference on VUV usage to decompose refractory micropollutants.     

Pressure dependence of Néel transition in (Mg,Fe)O

Pressure dependence of Néel temperature (T _N) in (Mg_0.20Fe_0.80)O, (Mg_0.25Fe_0.75)O, and (Mg_0.30Fe_0.70)O was newly measured up to 1.14 GPa, using superconducting quantum interference device magnetometer and piston–cylinder-type pressure cell under hydrostatic condition. The dT _N/dP values of (Mg_0.20Fe_0.80)O, (Mg_0.25Fe_0.75)O, and (Mg_0.30Fe_0.70)O were determined as 4.0 ± 0.3, 2.7 ± 0.3, and 4.4 ± 0.4 K/GPa, respectively, in linear approximation; however, the T _N deviated from the linearity under nonhydrostatic conditions. The compositional dependence of dT _N/dP in (Mg_1?X Fe _X )O showed a rapid decay with increasing Mg components at X ≥ 0.75 and the trend ended at X = 0.70. The estimated Néel transition pressure at room temperature by extrapolating these linearities are very similar to the rhombohedral distortion determined by previous X-ray diffraction studies for X ≥ 0.75, which suggests that the rhombohedral phase of (Mg_1?X Fe _X )O (X ≥ 0.75) at room temperature is antiferromagnetic under hydrostatic conditions.     

Stream channel erosion in a rapidly urbanizing region of the US–Mexico border: documenting the importance of channel hardpoints with Structure‐from‐Motion photogrammetry

Urbanization can lead to accelerated stream channel erosion, especially in areas experiencing rapid population growth, unregulated urban development on erodible soils, and variable enforcement of environmental regulations. A combination of field surveys and Structure‐from‐Motion (SfM) photogrammetry techniques was used to document spatial patterns in stream channel geometry in a rapidly urbanizing watershed, Los Laureles Canyon (LLCW), in Tijuana, Mexico. Ground‐based SfM photogrammetry was used to map channel dimensions with 1 to 2 cm vertical mean error for four stream reaches (100–300 m long) that were highly variable and difficult to survey with a differential GPS. Regional channel geometry curves for LLCW had statistically larger slopes and intercepts compared with regional curves developed for comparable, undisturbed reference channels. Cross‐sectional areas of channels downstream of hardpoints, such as concrete reaches or culverts, were up to 64 times greater than reference channels, with enlargement persisting, in some cases, up to 230 m downstream. Percentage impervious cover was not a good predictor of channel enlargement. Proximity to upstream hardpoint, and lack of riparian and bank vegetation paired with highly erodible bed and bank materials may account for the instability of the highly enlarged and unstable cross‐sections. Channel erosion due to urbanization accounts for approximately 25–40% of the total sediment budget for the watershed, and channel erosion downstream of hardpoints accounts for one‐third of all channel erosion. Channels downstream of hardpoints should be stabilized to prevent increased inputs of sediment to the Tijuana Estuary and local hazards near the structures, especially in areas with urban settlements near the stream channel. Copyright © 2017 John Wiley & Sons, Ltd.     

Investigating the vibration properties of integrated ceiling systems considering interactions with surrounding equipment

Studies on recent earthquakes highlighted that buildings with minimal structural damage still suffer from extensive damage and failure of nonstructural components. The dropping and damage of suspended ceiling systems, which typically consist of acceleration-sensitive nonstructural elements, resulted in lengthy functional disruptions and extended recovery time. This article experimentally and analytically examined the vibration properties of an integrated ceiling system considering the interactions with surrounding electrical equipment. The theoretical stiffness and corresponding frequency of electrical equipment were initially derived and then verified by subsequent vibration tests and numerical analyses. The seismic performance of the air conditioner (AC) was evaluated with different installment configurations based on design spectra and floor response spectra. Vibration tests of the suspended integrated ceiling system considering the interactions with surrounding equipment showed that the inclusion of peripheral constraints increased the first horizontal vibration frequency of the ceiling system by a factor of approximately 6. The natural frequencies of all components in the integrated ceiling system were almost identical, which was attributed to the coupled behavior between the ceiling panels and surrounding equipment, emphasizing the effect of interactions between adjacent components during dynamic analysis. Based on the above experimental investigation, an associated numerical model of the integrated ceiling system was created. Finally, corresponding parametric studies that included the interactions with surrounding equipment, reinforcing braces of ACs and strengthening members at the rise-up location between two elevations were performed.