Water Modulus Research Articles

Influence of Two Cooling Methods on Dynamic Mechanical Properties of High Temperature Sandstone

To study the influence of different cooling methods on dynamic mechanical properties of high temperature rock, both natural cooling and water cooling were used to cool high temperature (100°C∼1000°C) coal mine sandstone to room temperature (20°C). Basic physical parameters of sandstone were measured, and impact compression tests were carried out by using the SHPB test device. Comparative analysis shows that the volume expansion rate, mass loss rate, density reduction rate, and P-wave velocity reduction rate of sandstone specimens are positively correlated with the temperature in a quadratic function. The deteriorate rate of physical parameters of water cooling sandstone specimens is slightly larger than that of natural cooling. The variation of dynamic stress-strain curves is basically consistent. Compaction stage of water cooling is slightly larger than that of natural cooling. With the increase in temperature, dynamic compressive strength of sandstone specimens first increases, then decreases, and reaches maximum at 300°C. Subsequently, dynamic compressive strength decreases in a quadratic function with the temperature, and dynamic compressive strength of water cooling sandstone specimens is significantly lower than that of natural cooling. The dynamic elastic modulus also first increases and then decreases with the temperature and reaches maximum at 300°C. The dynamic elastic modulus of water cooling sandstone specimens is lower than that of natural cooling, but they are roughly the same at 1000°C. Dynamic strain increases in a quadratic function with the temperature, and dynamic strain of water cooling sandstone specimens is greater than that of natural cooling. The impact failure of sandstone specimens is intensified with the temperature, and the failure degree of water cooling is greater than that of natural cooling.

Water resource system vulnerability assessment of the Heihe River Basin based on pressure-state-response (PSR) model under the changing environment

Abstract As one of the most important inland rivers in China, the shortage of water resources and ecological deterioration of the Heihe River has increasingly attracted attention, and it is very significant to undertake the water resources sustainable utilization for its vulnerability assessment in the river basin. Using the pressure-state-response (PSR) model, a vulnerability index of the water resources system was developed and used to carry out a vulnerability assessment on the Heihe River in the current year (2010) and the comparison year (2003). The PSR of water resource vulnerability included 11 indexes, which are domestic water quota of urban residents, rural water quota of urban residents, million yuan GDP water consumption, per capita water consumption, ecological water proportion, drought index, per capita water resources, water modulus, water quality grade, water saving irrigation rate, per capita GDP, respectively. The vulnerability of water resources was evaluated by the attribute recognition model. The results show that water resources in the Heihe River Basin were in a quite vulnerable state in both 2003 and 2010 according to the values of scenario A1 (not vulnerable) and scenario B1 (severely vulnerable). It is urgent to protect and restore the water resources system in the Heihe River Basin.

Storage in confined aquifer: Spectral analysis of groundwater responses to seismic Rayleigh waves

Summary It is frequently found that the fluctuations observed in aquifer-well systems demonstrate high coherence to nearby boundary disturbances, or more specific, in response to the vertical motion of seismic Rayleigh waves. This study derives the spectral relationship between groundwater head and vertical displacement disturbed by Rayleigh waves in the time-frequency domain. Essentially, the groundwater storage property, e.g. storage coefficient or specific storage, representing the amount of water released from storage when the head changes from water expansion and aquifer compression occur. They can be determined using the spectral representation of the factors associated to groundwater head and Rayleigh waves. For this study, the Sumatra-Andaman Islands Earthquake with magnitude 9 at UT 2004/12/26 00:58:53.45 is used as the seismic source while a groundwater monitoring well and a seismological station located on the east of Taiwan acted as the receivers. The time series data associated with the observed groundwater head and vertical displacement of Rayleigh waves are used to evaluate spectral response analyzing the autospectral density, cross-spectral density, and coherence between them. The resultant spectral estimates can be used to determine the storage coefficient and specific storage of the case site to be on the order of 10−3 and 10−4 (m−1), respectively. In addition, the matrix bulk modulus also demonstrated a linear trend with porosity by taking the value of standard water modulus. It suggests that the storage of an aquifer can be robustly estimated using spectral representations and responses from head changes in groundwater and vertical displacement of Rayleigh waves.

Water characteristic curves and water status indicator

This paper attempts to introduce specific analytical meanings for the frequently used terms “water stress” (Falkenmark 1992, Vorosmarty et al.2000, 2005) and “water strain” (Haddadin 2007) by drawing an analogy from the science of engineering mechanics. It introduces “water characteristic curves” and a “water modulus” that defines the status of indigenous water of a given country. Compared to other tools that have been introduced to reflect the “water footprint” of a country (Hoekstra and Chapagain 2008), the water modulus is different in approach and meaning and is more reflective of the adequacy of indigenous water resources of countries.

Determination of the shear strength and modulus of water at low flow velocities

Damped inertial water flow in a cylindrical vessel is investigated. A return effect or "recoil" as the shear strain rate falks to a value of the order of 10−3s−1 is observed. Over the range of low strain rates the water behaves like a medium with very low shear strength and a shear modulus of the order of 10−6 Pa.

Refractory compound based on low modulus water glass for ramming linings of arc melting furnaces

The acid linings of the walls of e lectr ic arc furnaces in mos t factor ies are made from dinas. In the walls of arc furnaces the r e f r ac to ry operates in par t icular ly severe conditions. When the furnace is charged from the top the rate of change of tempera ture in the s t ructure is more than 1000~ and so the brick lining of the walls usually has a low res is tance -severa l tens of melts. The repa i r to the brick s t ructure is costly in labor and the consumption of expensive re f rac tor ies .

A note on the units of membrane permeability to water

In the usual experimental technique, the membrane permeability to water in the units of cm/sec is not measured directly. The quantity which is usually obtained may be considered to be a measure of a coefficient of penetrability having the dimensions time/length. The purpose of this paper is to show that by introducing the bulk modulus of water, an expression is obtained from which it is possible to calculate the water permeability in the units of cm/sec from the values in conventional units.