Tetroon flights across a ridge

Two series of tetroon flights across a long reasonably two-dimensional ridge with crest elevation of about 100 m were performed during the summers of 1977 and 1978. All of the tetroons were ballasted to float at an equilibrium level of 100 m above the ground. The first series was released in the daytime. Large instabilities were observed during windy neutral atmospheric conditions as well as on days with strong thermal convection. Under more stable conditions the air flow was observed to reflect the structure of the terrain more closely. The second series of tetroons was released on clear nights when stable atmospheric conditions prevailed. The natural wavelengths for these flights were approximately the same as the total base width of the ridge (~1.5 km). Some implications for pollutant dispersion calculations in areas of complex terrain are discussed.     

Source modeling of the Hsingtai,China earthquakes of March 1966

The Hsingtai, China earthquakes of March 1966 were a series of destructive earthquakes associated with the Shu-lu graben. Five strong shocks of M_s ≥ 6 occurred within a period of less than a month, the largest of which was M_s 7.2. Body and surface waves over the period range from several to 100 s have been modeled for the four largest events using synthetic seismograms in the time domain and spectral analysis in the frequency domain. Data from ground deformation, local geology, regional seismic network, and teleseismic joint epicenter determination have also been used to constrain the source model and the rupture process.The fault mechanism of the Hsingtai sequence was mainly strike-slip with a small component of normal dip-slip. The strikes of the four largest shocks range from ～ N26° to 30°E, approximately along strike of the major faults of the Shu-lu graben and the aftershock distribution. The source mechanisms can be explained with a NNW-SSE extensional stress and a NEE-SWW compressional stress acting in the area. The major shocks all had focal depths ～ 10 km.The four largest shocks in the sequence were characterized by a relatively simple and smooth dislocation time history. The durations of the far-field source time functions ranged from 3.5 to 5 s, while the rise times were all ～ 1 s. The seismic moments of the four largest earthquakes ranged from 1.43 × 10²⁵ to 1.51 × 10²⁶ dyne cm^?1. The fault sizes of the four events were very close. Assuming circular faults, the diameters of the four events were determined to be between 10 and 14 km. Stress drops varied from ～ 52 to 194 bars. A trend of increasing stress drop with earthquake size was observed.A survey of stress drop determinations for 15 major intraplate earthquakes shows that on the average the magnitude of stress drop of oceanic intraplate earthquakes and passive continental margin events is higher (～ 200 to several hundred bars) than that of continental intraplate earthquakes (～ 100 bars or less).     

Molecular characterization of four genes highly expressed during megalopa stage in Chinese mitten crab,Eriocheir sinensis

Ocean Science Journal - The molecular markers to distinguish different larval stages have various applications in ecological studies. Using the differential display RT-PCR technique, we isolated...     

Global spectral energy distributions of the Large Magellanic Cloud with interstellar dust

The effects of dust on infrared emission vary among galaxies of different morphological types. We investigated integrated spectral energy distributions (SEDs) in infrared and submillimeter/millimeter emissions from the Large Magellanic Cloud (LMC) based on observations from the Herschel Space Observatory (HSO) and near- to mid-infrared observations from the Spitzer Space Telescope (SST). We also used IRAS and WMAP observations to constrain the SEDs and present the results of radiative transfer calculations using the spectrophotometric galaxy model. We explain the observations by using dust models with different grain size distributions in the interstellar medium of the LMC, noting that the LMC has undergone processes that differ from those in the Milky Way. We determined a spectral index and a normalization factor in the range of ?3.5 to ?3.45 with grain radii in the range of 1 nm–300 nm for the silicate grain and 2 nm–1 μm for the graphite grain. The best fit to the observed SED was obtained with a spectral index of ?3.47, similar to the value derived by Piovan et al. (Mon. Not. R. Astron. Soc. 366(3):923, 2006a). The grain size distribution is described using a power law but with a break that is introduced below a _b , where a larger exponent is used. Changing the graphite grain size distribution significantly changed the SED pattern within the observational uncertainties. Based on the SED fits to the observations from submillimeter wavelengths to infrared radiation from the LMC using GRASIL (Silva et al., Astrophys. J. 509(1):103, 1998), we obtained a reasonable set of parameter values in chemical and geometric space together with the grain size distributions (Weingartner and Draine, Astrophys. J. 548(1):296, 2001) and a modified MRN model with the LMC extinction curve (Piovan et al., Mon. Not. R. Astron. Soc. 366(3):923, 2006a). For a given set of parameters including the disc scale height, synthesis of the starlight spectrum, optical depth, escape time scale, dust model, and star formation efficiency, the adopted dust-to-gas ratio for modeling the observed SEDs, ～1/300 (from the literature) yields a reasonable fit to the observed SEDs and similar results with the metallicity of the LMC as those reported in Russell and Bessell (Astrophys. J. Suppl. Ser. 70:865, 1989). The dust-to-gas ratios that are given as the metallicity caused the variation in the model fits. The difference mainly appears at the wavelengths near 100 μm.     

On the weak turbulent motions of an isothermal dry granular dense flow with incompressible grains: part I. Equilibrium turbulent closure models

The weak turbulent motions of a dry granular dense flow and the influence of the turbulent fluctuations caused by the minor short-term elastic/inelastic instantaneous collisions and the major long-term enduring frictional contacts among the grains on the mean flow characteristics are investigated. To this end, the conventional Reynolds-averaging process is applied to obtain the balance equations for the mean primitive fields associated with turbulent closure models. The thermodynamic analysis, based on the Mueller–Liu entropy principle, is carried out to derive the equilibrium formulations of the closure models. It shows that the effect of the turbulent fluctuations on the mean flow characteristics as well as the turbulent kinetic energy and dissipation can be taken into account by the granular coldness: a phenomenological measure of the fluctuating kinetic energy intensity. The implementation of the complete thermodynamically consistent turbulent closure models and the simulation of a gravity-driven stationary flow down an inclined moving plane compared with the experimental outcomes are provided in Part II of the present study.     

Influence of gravel segregation on gluing solution solidification in a railway ballast

Influence of gravel segregation on gluing solution distribution in a realistic railway ballasts is investigated numerically. The rheological characteristics of the gluing solution are accounted for by using a coupled elasto-visco-plastic stress model with an asymptotic time increasing viscosity. The realistic railway ballast is accomplished by using the vertex identification technique, in which the regulations of the gravel composition in ballast practice are followed. Specifically, a uniformly distributed one and a segregated one induced by the difference in gravel size and gravel shape are generated. The rheological model of the gluing solution and twofold ballasts are incorporated into the finite element code of ANSYS\(^{\copyright }\) to study the flow characteristics and time-dependent solidification of the gluing solution. Relatively concrete vertical and lateral gravel–gravel adhesion in twofold ballasts can be generated by using denser network arrangement of the gluing solution; the vertical penetration in the uniform ballast is slightly deeper than that in the segregated ballast, while a slightly reverse tendency in the lateral extension near the upper and central parts appears. However, the difference in the solidified gluing solution distributions in both ballasts is essentially insignificant, indicating that the influence of the gravel segregation needs not necessary to be taken into account in gluing practice when percolation is not taken into account.     

Spatial assessment of groundwater quality in the Jangseong region,South Korea

A total of 129 groundwater samples were collected in the Jangseong region of South Korea to characterize and evaluate groundwater quality and its suitability for irrigation and domestic uses. Samples were chemically analyzed for major ions, pH, electrical conductivity, and total dissolved solids following standard methods. The AquaChem 2014.2 model linked with PHREEQC was used for the statistical analysis and characterization of the hydrochemistry of the groundwater. The analysis showed that in all samples Ca–HCO₃ was the leading water type and that the abundance of major cations was in the order Ca > Na > Mg > K, and of anions in the order HCO₃ > Cl > SO₄ > F. According to the correlation analysis, Ca showed strong interdependence with HCO₃, suggesting that these parameters may have originated from common sources. Saturation index calculations indicated that all samples were undersaturated with respect to aragonite, calcite, dolomite, fluorite, gypsum, halite, and siderite, and oversaturated with respect to goethite and hematite. The irrigation suitability analysis revealed that groundwater in the Jangseong area can be used for irrigation without any restrictions based on EC, sodium adsorption ratio, percent sodium, residual sodium carbonate, Kelley ratio, permeability index, and the US Salinity Laboratory diagram analysis. The drinking water suitability analysis made for major parameters by comparison with the WHO guidelines indicates that the groundwater in the area is suitable for drinking except in some samples with high nitrate–N concentrations. The elevated nitrate concentrations in the groundwater are likely an indicator of agricultural pollution.     

A review of conventional techniques for subsurface characterization of landslides

Naturally occurring landslides can be difficult to characterize and often exhibit anomalies in controlling geometry and consistency. The characterization of landslides in engineering geology practice is usually based on program of subsurface exploration; focused on identifying subsurface materials, structure and stratigraphy, hydrologic conditions, and appropriate strength parameters. On native slopes bereft of anthropogenic modification (excavation), geomorphic evidence of previous movement and its relative depth and scale are often discernible to the experienced eye. This paper seeks to describe the various techniques that have been successfully employed in site-specific subsurface investigations of prehistoric landslides. These include considerations of limiting geometry (for planning subsurface exploration and sampling), overcoming problems with site access, exploratory trenches, small diameter borings, downhole logging of large diameter borings, and geophysical techniques. These procedures can be combined to develop more realistic cross sections along the vector of maximum landslide movement, so the displaced mass can be realistically analyzed. The respective advantages and disadvantages of these techniques are discussed, with baseline references on subsurface exploration.     

Derivation of regression coefficients for sea surface temperature retrieval over East Asia

Among the regression-based algorithms for deriving SST from satellite measurements, regionally optimized algorithms normally perform better than the corresponding global algorithm. In this paper,three algorithms are considered for SST retrieval over the East Asia region (15°-55°N, 105°-170°E),including the multi-channel algorithm (MCSST), the quadratic algorithm (QSST), and the Pathfinder algorithm (PFSST). All algorithms are derived and validated using collocated buoy and Geostationary Meteorological Satellite (GMS-5) observations from 1997 to 2001. An important part of the derivation and validation of the algorithms is the quality control procedure for the buoy SST data and an improved cloud screening method for the satellite brightness temperature measurements. The regionally optimized MCSST algorithm shows an overall improvement over the global algorithm, removing the bias of about -0.13℃ and reducing the root-mean-square difference (rmsd) from 1.36℃ to 1.26℃. The QSST is only slightly better than the MCSST. For both algorithms, a seasonal dependence of the remaining error statistics is still evident. The Pathfinder approach for deriving a season-specific set of coefficients, one for August to October and one for the rest of the year, provides the smallest rmsd overall that is also stable over time.     

八达岭基性岩和高Ba—Sr花岗岩地球化学特征及成因探讨：华北和大别—苏鲁造山带中生代岩浆岩的对比

八达岭杂岩侵位于华北北部，由辉长闪长岩岩、石英闪长岩、石英二长岩、二长闪长岩、二长花岗岩、碱长花岗岩和石英正长岩等组成，主要属高钾钙碱性系列。除了含V-Ti磁铁矿的堆晶辉长闪长岩，整套岩石的主量元素变化范围较大，SiO2=46.5%-75.3%,MgO=5.6%-0.2%，中酸性岩石的K2O/NaO为0.59-1.09。碱长花岗岩和少数石英二长岩Ba和Sr含量较低，且具有明显（Eu）负异常。大多数中酸性岩石（高Ba-Sr花岗岩）具有如下显著的微量元素地球化学特征：Ba,Sr和轻稀土（LREE）富集，Y和重稀土（HREE）亏损，LREE/HREE强烈分离，Sr/Y和La/Yb比值较高；在原始地幔标准化的蛛网图中具有显著的Nb,Ta和Ti亏损，不具明显的Sr和Eu亏损。在Harker图解中，基性岩石和高Ba-Sr花岗岩的主量元素相关性明显，两者还具有相似的微量元素和稀土（REE）分配特征，并且，REE,Y,Sr,P和Ti含量从基性到酸性逐渐降低。辉长闪长岩和高Ba-Sr花岗岩的Sr-Nd同位素初始值呈EMI特征（Isr=0.7051-0.7068,εNdi=-8.2-20.2），大致呈负相关。地球化学特征表明基性岩浆为富集的大陆岩石圈地幔部分熔融形成，而高Ba-Sr花岗岩则为基性岩浆通过陆壳混染和结晶分离形成；富P和Ti的副矿物（如磷灰石和的榍石）的分离结晶导致了REE,P和Ti丰度的逐渐降低。另外，华北板块内部和大别-苏鲁造山带基性岩和高Ba-Sr花岗岩分别具有相似的地球化学特征，这表明，上述地区燕山期大规模岩浆活动具有相似的地球动力学机制，大别-苏鲁造山带岩浆岩的地球化学特征并不反映其地幔源区一定受到过来自深俯冲的扬子板块的流体的富集作用。岩石圈的拆沉和减簿作用可能导致了华北板块和大别-苏鲁造山带下古老岩石圈地幔的部分熔融，岩石圈地幔的富集作用可能主要性发生于元古代。