Geohazards induced by anthropic activities of geoconstruction: a review of recent failure cases     

Khalid Elbaz  Jack S. Shen  Arul Arulrajah  Suksun Horpibulsuk 《Arabian Journal of Geosciences》2016,9(18):708

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Heat transfer and thermal boundary layers in high amplitude annulus waves     

Jack A. C. Kaiser 《地球物理与天体物理流体动力学》2013,107(1):357-379

Abstract

The heat transfer by a rotating, differentially-heated annulus of fluid is measured throughout the high amplitude wave regime. Only Δr_w T was varied (although v(T₁₅ ).K(T₁₅ ) varied by 46%), and it is found that Nu = C₁(λ)Ra^? away from the symmetry and low amplitude to wave transition curves and this is independent of ω. (λ is the wavelength.) On the wave side of these transition curves a region exists in which Nu (symmetry) λ Nu λ C₁(λ)Ra^?. The local heat transfer rate also varies strongly with wave phase.

Using a selection of measured internal thermal fields in the steady, high amplitude wave regime, the side-wall thermal boundary layer structure is examined. It is found that Nu, = C₂·Gr₂ ^A2; both C ₂ and A ₂ are independent of ω and λ to first order. For the time mean profiles, A ₂ ≈ 0.25; in the high heat transfer portion of the wave A ₂ < ¼ and in the low heat transfer portion of the wave A ₂ > ?. These relations hold over most of the vertical extent of the side walls. The deviations of the boundary layers from the above behavior which occur on the remainder of the walls is illustrated. The average thicknesses of the wall boundary layers ∞ Ra^?¼ except in that phase of the wave in which the wall to mid-gap temperature difference is the largest.  相似文献   

Preface     

Jack Hardisty 《地球表面变化过程与地形》1994,19(9):775-775

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Book reviews     

W. E. Sharp  Jack Daemen 《Mathematical Geosciences》1995,27(4):549-554

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DISCUSSION OF "A Program to Calculate Aquifer Transmissivity from Specific-Capacity Data for Programmable Calculators," by J. B. Czarnecki and R. W. Craig     

Jack E. Kelly 《Ground water》1986,24(2):237-237

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An evaluation of flow-stratified sampling for estimating suspended sediment loads     

Robert B. Thomas  Jack Lewis 《Journal of Hydrology》1995,170(1-4):27-45

Flow-stratified sampling is a new method for sampling water quality constituents such as suspended sediment to estimate loads. As with selection-at-list-time (SALT) and time-stratified sampling, flow-stratified sampling is a statistical method requiring random sampling, and yielding unbiased estimates of load and variance. It can be used to estimate event yields or to estimate mean concentrations in flow classes for detecting change over time or differences from water quality standards. Flow-stratified sampling is described and its variance compared with those of SALT and time-stratified sampling. Time-stratified sampling generally gives the smallest variance of the three methods for estimating storm yields. Flow-stratified sampling of individual storms may fail to produce estimates in some short-lived strata because they may have sample sizes of zero. SALT will tend to give small samples and relatively high variances for small stroms. For longer and more complex hydrographs, having numerous peaks, flow-stratified sampling gives the lowest variance, and the SALT variance is lower than that of time-stratified sampling unless the sample size is very large. A desirable feature of flow-stratified sampling is that the variance can be reduced after sampling by splitting strata, particularly high flow strata that have been visited just once, and recalculating the total and variance. SALT has the potential to produce the lowest variance, but cannot be expected to do so with an auxiliary variable based on stage.  相似文献   

Syntectonic vein development in a thrust sheet from the external French Alps     

Alastair Beach  Sue Jack 《Tectonophysics》1982,81(1-2)

The geometry and age relations of syntectonic veins within calcareous rocks of one imbricate sheet within a thrust belt in the external French Alps, are described.The earliest veins developed during the main ductile deformation by cleavage-parallel extension. The majority of the syntectonic veins developed towards the end of the deformation, and after the formation of second folds. They include a conjugate set of normal shears, an abundant set of upright extension veins, and en echelon sets.The dominantly simple shear strain making up the main ductile phase of deformation occurred by a mechanism of grain to grain pressure solution. The stretching lineation records the overall direction of thrust sheet movement. A change in the microchemical mechanism of pressure solution is thought to have caused the change from first to second phase deformation as recorded by slaty cleavage and crenulation folds in the field. From the shear and vein geometries, directions of principal stress have been inferred. The directions rotated throughout the deformation, the maximum principal stress being inclined to bedding during simple shear strain, becoming normal to bedding during the phase of abundant vein growth, and becoming vertical at the very end of the deformation.  相似文献   

Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA)   总被引：10，自引：3，他引：7  

Alexander P. Wolfe  Jill S. Baron  R. Jack Cornett 《Journal of Paleolimnology》2001,25(1):1-7

Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted ¹⁵N values. These trends are particularly pronounced since ~ 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturingthe entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.  相似文献   

New Jersey law controlling estuary development     

Jack B. Pearce 《Marine pollution bulletin》1971

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MAPPING FROM AN AUTOMATED DISPLAY SYSTEM*     

Kurt E. Brassel  Jack J. Utano 《The Professional geographer》1979,31(2):191-200

This paper outlines recent developments in computer mapping and points out its importance for visualizing contents of geographic information systems. The authors present an integrated system of mapping packages and spatial-data files. Map examoles generated with this system are used to illustrate characteristics of various computer-mapping methods. The diversity of displays created from a single set of data demonstrates that mapping from automated display systems requires the user to take some decisions which have to be based on an understanding of the phenomena displayed, of cartographic communication, and of technical aspects of automated map processing.  相似文献