Porosity evaluations

Thus gas adsorption provides essentially important information on the nanopores from the sub-nanometer level, which is often inherent to a specific molecule. Also the density measurement is necessary for the exact porosity evaluation. The accurate particle and true densities give close porosity. Even He molecules are adsorbed in small nanopores at room temperature and thereby the He replacement method is not fit for determination of the particle density. Authors developed the high pressure He buoyancy method until 10... 

Comparison of the porosity evaluation results based on immersion calorimetry and gravimetric sorption measurements, for activated chars from a high volatile bituminous coal... 

Comparison of the porosity evaluation results based on immersion... 

Gamma ray attenuation porosity evaluator (GRAPE) Instrument that measures gamma ray attenuation through unsplit cores and provides an estimate for bulk density, water content, and porosity. 

NH2—CH2—CH2—NH2). Dendrimers are ideal macromolecular standards for use in size exclusion chromatography, membrane porosity evaluation, Newtonian viscosity applications, and electron microscopy. Unique, high surface functionality (Z may range from 2,3, or 4 to several thousand) provides nanoscopic building blocks for complex nanoconstructions based on either covalent bonding or self assembly-type processes. In the biomedical field. 

A vast variety of logging tools are In existence and Section 5.4 will cover only those which enable the evaluation of essential reservoir parameters, specifically net reservoir thickness, lithology, porosity and hydrocarbon saturation. 

The results presented below were obtained using a 2 mm thick carbon fiber reinforced epoxy composite laminate with 16 layers. The laminate was quasi isotropic with fiber orientations 0°, 90° and 45°. The laminate had an average porosity content of approximately 1.7%. The object was divided in a training area and an evaluation area. The model parameters were determined by data solely from the training area. Both ultrasound tranducers used in the experiment had a center frequency of 21 MHz and a 6 dB bandwidth of 70%. 

F.A. Reed, T. Batzinger, R.W. Reed, and S. Jonsson. Porosity measurement of composites using attenuation methods. Review of Progress in Quantitative Nondestructive Evaluation, 12, 1993. 

Isotherms of Type 111 and Type V, which are the subject of Chapter 5, seem to be characteristic of systems where the adsorbent-adsorbate interaction is unusually weak, and are much less common than those of the other three types. Type III isotherms are indicative of a non-porous solid, and some halting steps have been taken towards their use for the estimation of specific surface but Type V isotherms, which betoken the presence of porosity, offer little if any scope at present for the evaluation of either surface area or pore size distribution. 

A manual entitled Reporting Physisorption Data for Gas/Solid Systems with Special Reference to the Determination of Surface Area and Porosity has been prepared as a provisional publication by Commission 1.6 of the International Union of Pure and Applied Chemistry (lUPAC). The purpose of the manual is to draw attention to problems involved in reporting physisorption data and to provide guidance on the evaluation and interpretation of isotherm data. The general conclusions and recommendations are very similar to those contained in Chapter 6. 

The properties and performance of cemented carbide tools depend not only on the type and amount of carbide but also on carbide grain size and the amount of biader metal. Information on porosity, grain size and distribution of WC, soHd solution cubic carbides, and the metallic biader phase is obtained from metaHographicaHy poHshed samples. Optical microscopy and scanning and transmission electron microscopy are employed for microstmctural evaluation. Typical microstmctures of cemented carbides are shown ia Figure 3. 

Surface Area and Permeability or Porosity. Gas or solute adsorption is typicaUy used to evaluate surface area (74,75), and mercury porosimetry is used, ia coajuactioa with at least oae other particle-size analysis, eg, electron microscopy, to assess permeabUity (76). Experimental techniques and theoretical models have been developed to elucidate the nature and quantity of pores (74,77). These iaclude the kinetic approach to gas adsorptioa of Bmaauer, Emmett, and TeUer (78), known as the BET method and which is based on Langmuir s adsorption model (79), the potential theory of Polanyi (25,80) for gas adsorption, the experimental aspects of solute adsorption (25,81), and the principles of mercury porosimetry, based on the Young-Duprn expression (24,25). 

To determine the average porosity of a homogeneous but nonuniform medium, the correct mean of the distribution of porosity must be evaluated. The porosities of natural and artificial media usually are normally distributed. The average porosity of a heterogeneous nonuniform medium is the volume-weighted average of the number average ... 

Fractures, fissures, and joints are openings in sedimentary rocks formed by the structural (mechanical) failure of the rock under loacls caused by earth crust tectonics. This form of porosity is extremely hard to evaluate quantitatively due to its irregularity. 

The various volumes of rock matrix, shale, porosity, overpressure porosity and hydrocarbons are used to compute the various tool responses according to a model. The responses are compared to the measured values and a volume optimization is made to minimize the errors grouped in an incoherence function. The value of the incoherence function for the best fit determines the quality of the answer. Figure 4-335 is an example of formation pressure calculation as well as formation evaluation for lithology and fluid content. 

In all zones the discrepancies between LWD and wireline porosity data are in the range of one to five porosity units. Thus, the LWD neutron data are suitable for formation evaluation. 

The examples discussed above suggest useful directions for future research involving trace element analysis of bones. Specifically, the effects of developmental age and other factors (e.g., porosity, mineralization) that may lead to differences in surface area of specimens should be considered. Diage-netic effects should be monitored by analysis of a suite of elements whose abundances are not controlled by dietary abundances (e.g., Mn, Zr, etc.). Finally, although alkaline elements such as Sr and Ba are most likely to reflect the Sr/Ca and Ba/Ca levels of the diet, omnivores such as humans are likely to obtain the majority of these elements from plants rather than from animals. Therefore for accmate diet reconstruction it is necessary to determine the total abundance of Ca as and the Sr/Ca and Ba/Ca ratios of the plant and animal resources that were potential dietary staples. The effects of culinary practices on elemental abundances (Burton and Wright 1995 Katzenberg et al. this volume) must also be evaluated. 

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