There are various types of the windblown sediment traps developed for wind tunnel and field studies. One of the main supports
expected from these traps is in measuring surface dust concentrations to appropriately derive flux equations. The measurement
performance and accuracy of a trap is very important and depends strictly upon the physical characteristics and the behaviors
of dust grains with air flows. This paper presents the measurement results of static pressure distribution (SPD) of wind flow
around Vaseline-coated slide (VCS) catchers with an aim of finding out whether or not particle trapping efficiency (η) of
the VCS is related to the SPD. The SPD was evaluated by a wind reduction coefficient (Rc) in a series of wind tunnel experiments with different VCS settings which have different attachment configurations on a pole.
Three VCS configurations were considered: a configuration on a circular plastic pole (CPP) and two configurations on wooden
square poles (WSP1 and WSP2, respectively). Thus, the primary contribution of this work was to experimentally analyze the effect of the different attachment
configurations on the SPD, and the secondary objective was to determine the effect of the SPD on the η. It was shown that
spatial correlation and spatial pattern of the Rc were different in the surrounding area of each configuration, and ANOVA and DUNCAN tests indicated that η(s) of WSP1, WSP2, and CPP were different at the significant level of P ≤ 0.05 with the mean of 0.94 ± 0.09, 0.63 ± 0.14, and 1.13 ± 0.07, respectively. Additionally, the amount of PM20, PM40, PM60, PM80, and PM100 trapped by the configurations of WSP1, WSP2, and CPP considerably varied depending upon the particular aerodynamic circumstances associated with every configuration. 相似文献
The universal soil loss equation (USLE) is an erosion model to estimate average soil loss that would generally result from
splash, sheet, and rill erosion from agricultural plots. Recently, use of USLE has been extended as a useful tool predicting
soil losses and planning control practices by the effective integration of the GIS-based procedures to estimate the factor
values on a grid cell basis. This study was performed for five different lands uses of Indağı Mountain Pass, Cankırı to predict
the soil erosion risk by the USLE/GIS methodology for planning conservation measures in the site. Of the USLE factors, rainfall-runoff
erosivity factor (USLE-R) and topographic factor (USLE-LS) were greatly involved in GIS. These were surfaced by correcting
USLE-R site-specifically using DEM and climatic data and by evaluating USLE-LS by the flow accumulation tool using DEM and
watershed delineation tool to consider the topographical and hydrological effects on the soil loss. The study assessed the
soil erodibility factor (USLE-K) by randomly sampled field properties by geostatistical analysis. Crop management factor for
different land-use/land cover type and land use (USLE-C) was assigned to the numerical values from crop and flora type, canopy
and density of five different land uses, which are plantation, recreational land, cropland, forest and grassland, by means
of reclassifying digital land use map available for the site. Support practice factor (USLE-P) was taken as a unit assuming
no erosion control practices. USLE/GIS technology together with the geostatistics combined these major erosion factors to
predict average soil loss per unit area per unit time. Resulting soil loss map revealed that spatial average soil loss in
terms of the land uses were 1.99, 1.29, 1.21, 1.20, 0.89 t ha−1 year−1 for the cropland, grassland, recreation, plantation and forest, respectively. Since the rate of soil formation was expected
to be so slow in Central Anatolia of Turkey and any soil loss of more than 1 ton ha−1 year−1 over 50–100 years was considered as irreversible for this region, soil erosion in the Indağı Mountain Pass, to the great
extent, attained the irreversible state, and these findings should be very useful to take mitigation measures in the site. 相似文献
In this work, some numerical solutions of magnetohydrodynamic equations are investigated in the presence of radial and azimuthal components of magnetic field with the use of previously developed algorithm. In this algorithm, the thin shell approximation and a special separation of variables is used to obtain the radial and latitudinal variations of physical parameters in spherical coordinates. The solutions are obtained via this separation of variables in the components of momentum transfer equation. The analysis yields three important parameters which are the sphericity, density and radial components shape parameters in the latitudinal distributions of physical variables. The magnetic field profile, used here, produces comparable magnetic fluxes found in previous works. There is a considerable change in density with respect to reference model. Other physical parameters also reveal important physical results. It is as well shown that the spherical symmetric distributions of physical parameters are broken for the region of study. 相似文献
Scenario‐based earthquake simulations at regional scales hold the promise in advancing the state‐of‐the‐art in seismic risk assessment studies. In this study, a computational workflow is presented that combines (i) a broadband Green's function‐based fault‐rupture and ground motion simulation—herein carried out using the “UCSB (University of California at Santa Barbara) method”, (ii) a three‐dimensional physics‐based regional‐scale wave propagation simulation that is resolved at Hz, and (iii) a local soil‐foundation‐structure finite element analysis model. These models are interfaced with each other using the domain reduction method. The innermost local model—implemented in ABAQUS—is additionally enveloped with perfectly matched layer boundaries that absorb outbound waves scattered by the structures contained within it. The intermediate wave propagation simulation is carried out using Hercules , which is an explicit time‐stepping finite element code that is developed and licensed by the CMU‐QUAKE group. The devised workflow is applied to a km region on the European side of Istanbul, which was modeled using detailed soil stratigraphy data and realistic fault rupture properties, which are available from prior microzonation surveys and earthquake scenario studies. The innermost local model comprises a chevron‐braced steel frame building supported by a shallow foundation slab, which, in turn, rests atop a three‐dimensional soil domain. To demonstrate the utility of the workflow, results obtained using various simplified soil‐structure interaction analysis techniques are compared with those from the detailed direct model. While the aforementioned demonstration has a limited scope, the devised workflow can be used in a multitude of ways, for example, to examine the effects of shallow‐layer soil nonlinearities and surface topography, to devise site‐ and structure‐specific seismic fragilities, and for calibrating regional loss models, to name a few. 相似文献
In the present paper
n0
, for occulation and transit eclipses of partial phases, are evaluated numerically by means of the Runge-Kutta methods. Section 2 contains the required differential equations of
n0
with respect to the modulusX orC, and Section 3 includes the numerical method of the solutions of these differential equations. Theoretical values of
00
and
10
, with corresponding values ofC, are also added in this section. 相似文献
In this paper, the surface water quality of the Sakarya River in Turkey is assessed by using multivariate statistical techniques.
These techniques were applied to the chemical parameters obtained from the five different surface water quality observation
stations. Factor and principal component analysis results reveal that the agricultural, anthropogenic and domestic pollution
caused differences in terms of water quality. Cluster analysis revealed two different clusters of similarities between the
stations, reflecting different chemical properties and pollution levels in the studied river. Surface water quality downstream
of the river was different from the water quality upstream. Thus, this study shows the usefulness of multivariate statistical
techniques for analysis and interpretation in the surface water quality problem. 相似文献
This paper describes the application of an unsupervised clustering method, fuzzy c-means (FCM), to generate mineral prospectivity models for Cu?±?Au?±?Fe mineralization in the Feizabad District of NE Iran. Various evidence layers relevant to indicators or potential controls on mineralization, including geochemical data, geological–structural maps and remote sensing data, were used. The FCM clustering approach was employed to reduce the dimensions of nine key attribute vectors derived from different exploration criteria. Multifractal inverse distance weighting interpolation coupled with factor analysis was used to generate enhanced multi-element geochemical signatures of areas with Cu?±?Au?±?Fe mineralization. The GIS-based fuzzy membership function MSLarge was used to transform values of the different evidence layers, including geological–structural controls as well as alteration, into a [0–1] range. Four FCM-based validation indices, including Bezdek’s partition coefficient (VPc) and partition entropy (VPe) indices, the Fukuyama and Sugeno (VFS) index and the Xie and Beni (VXB) index, were employed to derive the optimum number of clusters and subsequently generate prospectivity maps. Normalized density indices were applied for quantitative evaluation of the classes of the FCM prospectivity maps. The quantitative evaluation of the results demonstrates that the higher favorability classes derived from VFS and VXB (Nd?=?9.19) appear more reliable than those derived from VPc and VPe (Nd?=?6.12) in detecting existing mineral deposits and defining new zones of potential Cu?±?Au?±?Fe mineralization in the study area.
Bulletin of Earthquake Engineering - This paper investigates the seismic loss assessment of seismically isolated and non-isolated buildings with steel moment or braced frames, designed by the... 相似文献