Fractional Curves Research Articles

Researches on the Production of Furfural and High α-Pulp from Hard Wood (I)

For the purpose of examining the characteristic behaviors of new dissolving pulp manufactured by new method, several tests were carried out in comparing with Buckye's V5 and VX.Results are as follows;(1) The reactivity of this new pulp in emulsion xanthation is better than those of Buckye's V5 and VX.(2) From the results of the solubility curve by NaOH and the distribution curve of lateral order, it is considered that this new pulp is very profitable for viscose manufacture.(3) In the swelling test by 79 % H3PO4, this new pulp is already swollen in spiral type, but V5 and VX are not yet swollen in spiral type.(4) The fractional dissolution curves of samples by ethyl acetate-ethyl alcohol mixture, indicate that this new pulp also seems to be very profitable for dissolving pulp.

Researches on the Swelling of Fibers (V)

In previous paper, relations between the degree of hydrolysis and the morphological structures of fibers were discussed.In this paper, for the purpose of examining the relations between the morphological structures and several properties of cellulose fibers hydrolyzed by acid, pentosan and the average degree of polymerization of cellulose were determined on the following samples prepared from pine and beech (holocellulose, hydrolyzed holocellulose, holocellulose treated with 5% KOH, holocellulose treated with 5 % KOH and then hydrolyzed). The fractional dissolution curves of nitrates of the samples were also obtained by means of ethyl acetate-ethyl alcohol mixtures.Some differences both in the behaviors of pentosan and in the resistances of the cell walls during the hydrolysis are recognized between pine tracheid and beech wood fiber.

Classification Efficiency of Two-stage Hydraulic Cyclones

The hydraulic cyclone, as a hydraulic classifer, has rather good classifying characteristics, but its sharpness of classification is not satisfactory enough when compared with that of the ideal classifer. In this paper, possibilities are discussed of improving the classification efficiency of hydraulic cyclones by combining them in series. The two-stage cyclone employed in the experiment is the combination of three cyclones in which the first stage cyclone (I) is directly connected with two second-stage cyclones, one, in the overflow side (IIo) and the other in the undcrflow side (IIu) as shown in Figure 2.The overflow of IIo cyclone (OO) contains most of the fine particles and the underflow of IIo cyclone (UU) contains coarser particles. The underflow of IIo (OU) and the overflow of IIu cyclonc (UO) consist mainly of particles of intermediate sizes. When the feed material is to be classified into two products, namely fine and coarse products, both OU and UO must be returned to the feed tank and circulated as shown in Figure 3. We call such a system "two-stage cyclone of circulation type."In the former report1), the authors discussed the classification characteristics of one stage hydraulic cychones and represented they in the form of generalized fractional recovery curves. If the fractional recovery curves of all the coyponent cyclones areknown, the classification characteristics of a two-stage cyclone may be estimated from equation (2), where RI, RIIu, and RIIo are the fractional recoveries of I, IIu and IIo cyclones respectively for a certain particle size. The overall fractional recovery (RII) for the two-stage, circulation-type cyclone is defined as in equation (5), and the ratio of accumulation of particles by circulation (λ) as in equation (4). Examples of calculated values of RII andλfor two stage cyclones are shown in Figure 8.Newton's classification efficiencies are caiculated and tabulated in Table 1 which would be obtained when powdered materials, having Rosin-Lammler's type of particle distribution of equation (8), are classified at the cut size of 20 micron by a series of one-and two-stage cyclones, It is concluded from these results that the classifcation efficiency of a hydraulic cyclone may be markedly improved by these methods.

Liquid Cyclone as a Hydraulic Classifier

Performance characteristics of a liquid cyclone as a hydraulic classifier were examined with various cyclones having 3-6″ diameters, and their dimensions were shown in Tables 1, 2 and Fig. 2.Tangential velocity distribution, pressure drop, flow ratio, fractional recovery curve and 50% recovery particle size were measured under the various operating conditions.i) Velocity distribution. Two zones were observed in the cyclone as shown in Fig. 5. The one is the outer zone near the cyclone wall where the tangential velocity is approximately constant, and the other is the inner zone where the velocity distribution is represented by the equation urn=const, in which n equals approximately 0.8 with dilute slurry. Tangential velocity in the cyclone may be correlated with inlet velocity us by the equations (1)-(4).ii) Pressure drop through cyclones with various proportions may be represented by the experimental equation (7), which agrees fairly well with the theoretical equation (12) calculated from the velocity distribution.iii) Flow ratio depends primarily on the ratio Du/De and the feed pressure. As the pressure increases, the flow ratio decreases asymptotically to its minimum value which may be estimated by Oyama's equation (14) as a function of Du/De.iv) Classifying charateristics of liquid cyclone may be represented by the fractional recovery versus particle size curves. These curves with different flow ratios and operating conditions, differ from each other, but may be correlated to a single curve by correcting the flow ratio to zero through the procedure shown in Fig. 12 and equation (15), and plotting those reduced recovery values with d/d50' as shown in Fig. 13 where d50' is a 50% particle size in the reduced recovery curve.v) Standard proportion. The liquid cyclone having the proportion of Di/Dc=1/7, De/Dc=1/5 is recommended by the authors as a standard, whose capacity, pressure drop and the d50' values are shown diagramatically in Fig. 16, where the density of the solid particle is assumed to be 2.6 and the liquid is water at ordinary temperature.

Relation between Radiation Quality Factors and Depth

THE effects of radiant energy are quantitatively proportional to the radiation absorbed, and, therefore, whatever clinical result is to be produced in tissues will be proportional to the radiation absorbed in the tissues and at the location of the lesion to be treated. This is one of the axioms of modern physics and now a definitely accepted working principle of clinical radiation therapy known as Grotthus-Draper's law. As a further condition, because of the limitations imposed by skin erythema, the actual dose will be restricted to the accepted maximum skin tolerance dose and hence the tumor itself will receive but a fraction of this skin dose. Therefore, the efficiency of a given radiation for the therapeutic treatment of a deep-seated lesion is measured and expressed by the ratio of the dose tolerated by the skin to the dose absorbed by the tumor. I t is customary to represent this ratio for various depth locations by curves which are generally known as absorption curves, and the various methods used today for defining the quality of radiations are expedients to define such absorption curves (1). A curve of this kind, however, is an absorption curve in the true sense only when the actual intensity of the beam is measured by total absorption; if but a small fraction of the beam is measured, as we do with the commonly used ionization instruments and the radiation is monochromatic, then the curve is a fractional absorption curve (2). However, if the radiation beam is polychromatic and also measured with the small ionization chamber, then the measurements are not intensities but doses stopped in air and the true intensity of the radiation either at the surface or at the various depths is entirely unknown. The reason for this is that in the latter case as the radiation penetrates into the absorbing substance it is further filtered, with the result that the intensity as well as the average wave length and the absorption coefficient become smaller. A curve of this kind, therefore, represents the intensity of the beam multiplied by a fraction which indicates what portion of the beam is absorbed in the ionization chamber or, in other words, the product of the intensity times the absorption coefficient in air. It now becomes quite evident that if the absorption coefficient is small, then even though a substantial radiation intensity may reach the selected depth, since there is but little absorption, there also can be but little biologic effect. A curve of this kind does not represent the doses absorbed in a given volume or mass of tissues but, rather, it represents the intensity times the absorbability in air of the radiation at various depths. The latter factor is indicated by the slope of the curve, or the tangent or first differential coefficient, at the particular depth and this is equal to the absorption coefficient in air. Therefore, to distinguish such a curve from one which is a true absorption curve, we shall designate it as an absorbability curve.

Studies on the neutralization of gastric acidity: Ewald test meal and X-ray (barium meal) studies in patients with duodenal ulcer, gastro-jejunostomy and gastric resection

1. Gastric studies of 25 patients were made by means of x-ray (after a barium meal), fractional Ewald test meals and neutralization curves of gastric acidity. The patients comprised those with x-ray evidence of ulcer, both with and without symptoms, those with symptoms of ulcer but with negative x-ray findings, and those with gastro-enterostomies and gastric resections.