Distribution studies, experimental

Hydrogenation of lactose to lactitol on sponge itickel and mtheitium catalysts was studied experimentally in a laboratory-scale slurry reactor to reveal the true reaction paths. Parameter estimation was carried out with rival and the final results suggest that sorbitol and galactitol are primarily formed from lactitol. The conversion of the reactant (lactose), as well as the yields of the main (lactitol) and by-products were described very well by the kinetic model developed. The model includes the effects of concentrations, hydrogen pressure and temperature on reaction rates and product distribution. The model can be used for optinuzation of the process conditions to obtain highest possible yields of lactitol and suppressing the amounts of by-products. 

Models, based on well established mechanisms and "properly" validated with experimental data, can be useful in probing into areas impractical or impossible to study experimentally. For example, it is very difficult and time consuming to determine functionality distributions of oligomers or copolymers a "validated" polymerization model can calculate such distributions with relative ease. 

The resin system selected to initiate these studies is a step-growth anhydride cured epoxy. The approach to the kinetic analysis is that which is prevalent in the chemical engineering literature on reactor design and analysis. Numerical simulations of oligomeric population density distributions approximate experimental data during the early stages of the cure. Future research will... 

The distribution of the number of full contacts in RP was studied experimentally in Ref. [106], It was shown that the radial distribution function (RDF see Figure 9.24) corresponds to a normal distribution. Table 9.6 illustrates the results of that study analyzed on the basis of Equation 9.63 and Equation 9.64 (see Section 9.7.2). 

The distribution of liquid over packings has been studied experimentally by many workers and, for instance, Tour and Lerman164 65 showed that for a single point feed the distribution is given by ... 

The length-distribution studies were recently extended to include an estimate of the radii of gyration of the protein in situ (Ramakrishnan et ai, 1981). The constraint used was that the proteins must have a radius of gyration greater than that of an anhydrous sphere. From their results Ramakrishnan to/. (1981) conclude that only SI and S4 show signs of an extended conformation in situ, whereas 12 proteins (S3, S5, S6, S7, S8, S9, SIO, Sll, S12, S14, S15, and S18) appear quite compact and globular. However, the experimental errors of these estimations are very large. 

Before the development of lasers it was not possible, for instance, to study experimentally in any detail the spectral distribution of... 

Where are the electrons . This question too can only be studied experimentally for molecules in equilibrium and in a roughly homogeneous environment such as a crystal or in solution. What we really want to know is how the distribution of these electrons around the nuclei determine the likelihood of effective collision and how they then behave during the interaction. Since molecules interact most strongly at their accessible surfaces/ it is important to know what these surfaces look like. 

We then study experimentally the effect of an inert electrolyte solution and show that ion motion forces an applied electrical potential in the dark to drop near the substrate electrode, thus reinforcing the effects of the distributed resistance. Overall, the 2 conduction and valence bands (whose spatial gradients reflect the electric field) remain approximately flat both at equilibrium and under illumination therefore, charge transfer occurs primarily by diffusion rather than by field-induced drift [4,40-42]. Recent numerical simulations [43,44] and modeling of photogenerated trapped charges [45] show that in an illuminated DSSC there may be, in fact, a very small bulk electric field of about 0.1-3 mV/pm, but this is not expected to have much influence. 

Ya.B. considered that the most important adsorbents—porous coal, silica gel, and the powdered manganese dioxide which he had studied experimentally—are amorphous substances, i.e., they do not have clearly articulated crystalline structure. Only thus is it possible to obtain a large developed surface—the most important feature of an adsorbent. In this case, it is natural to consider all the possible values of adsorption activity and a smooth distribution function of surface sectors according to their level of activity. 

The onset of high electrical conductivity with increasing volume fraction of metallic particles has also been of interest in relation to theoretical treatments which consider the factors which control formation of a continuous disperse phase of randomly distributed particles. In pursuance of such work, the distribution of metallic particles was studied experimentally by quantitative microscopy of polished plane sections. A marked increase in conductivity was observed when the fractional volume loading of silver particles in Bakelite reached 0.36-0.38 ( 3). 

Small bubbles and flow uniformity are important for gas-liquid and gas-liquid-solid multiphase reactors. A reactor internal was designed and installed in an external-loop airlift reactor (EL-ALR) to enhance bubble breakup and flow redistribution and improve reactor performance. Hydrodynamic parameters, including local gas holdup, bubble rise velocity, bubble Sauter diameter and liquid velocity were measured. A radial maldistribution index was introduced to describe radial non-uniformity in the hydrodynamic parameters. The influence of the internal on this index was studied. Experimental results show that The effect of the internal is to make the radial profiles of the gas holdup, bubble rise velocity and liquid velocity radially uniform. The bubble Sauter diameter decreases and the bubble size distribution is narrower. With increasing distance away from the internal, the radial profiles change back to be similar to those before contact with it. The internal improves the flow behavior up to a distance of 1.4 m. 

In the inverted band a quite different pattern of intensity distribution is to be expected. In the pure crystal the topmost level alone is active it remains the strongest under all conditions. As the trap is deepened, some intensity moves from the topmost level downward through the band into the bottom level, which breaks out of the band and eventually becomes practically a localized state of the trapping molecule. Thus the presence of guest molecules awakens spectral activity in normally inactive levels, and should enable the extent and character of the pure crystal band structure to be studied experimentally. The point is illustrated in the diagrammatic spectra in Fig. 6, illustrating the transitions in one-dimensional mixed crystals for trap depths from zero (pure crystal) to d = 3.6. In each case the intensities are adjusted to make the lowest transition have unit intensity this... 

Variability of the patchy topology and vertical structure is connected with seasonal cycles and has been well studied experimentally in many climatic zones of the World Ocean. The typical qualitative and quantitative indicators of this variability have been found. The combined distributions of abiotic, hydrological, and biotic components of the ocean ecosystems have been studied. Vetrov and Roman-kevich (2004) analyzed conditions for the carbon cycle formation in the Barents, White, Kara, East-Siberian, and Chukchi Seas, considering the relationships between... 

Since Weiss and DeMarco (91) detected the asphericity in charge distribution in vanadium metal, the 3d electron distributions in crystals of V, Cr, and Fe have been studied experimentally as well as theoretically (89). Crystals of V, Cr, and Fe are body-centered cubic at room temperature and under normal pressure. Charge asphericity has... 

The initial charge distributions, which were recognized as very important, were analyzed in more detail in a number of works [32]. The analysis was extended to multichannel ionization [179], and the role of the excitation lifetime was specified [25]. A few articles devoted to them were published by Murata and Tachiya [26,27]. Earlier these authors studied experimentally the non-stationary kinetics of fluorescence quenching, which was fitted numerically... 

The aim of this paper is to describe the experimental and numerical techniques that, when combined, provide a procedure that enables full particle-size distribution studies of sub-micrometer emulsion systems. We then present distribution results for several oil/water emulsions to demonstrate the ability of these techniques to monitor the effect of processing variables (such as surfactant concentration) on the final emulsion. Finally, we discuss some of the problems of converting the intensity weighted distribution to a mass weighted distribution and suggest methods for minimizing or eliminating some of these problems. 

No studies were found that examined distribution in humans after dermal exposure to hydrogen cyanide there are limited data on the distribution in experimental animals after dermal exposure. Rabbits exposed by the dermal route to 33.75 mg CNYkg as hydrogen cyanide had cyanide concentrations of 310 fig/dL in the blood, 144 fig/dL in the serum, 26 fig/100 g in the liver, 66 fig/100 g in the kidney, 97 /rg/100 g in the brain, 10 fig/100 g in the heart, 120 jug/100 g in the lungs, and 21 fig/100 g in the spleen (Ballantyne 1983a). 

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