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The intensity and Rayleigh linewidth of light scattered by concentration fluctuations in a ternary ethanol‐water‐chloroform system have been studied as a function of angle and temperature. Critical exponents γx, νx, and η obtained from the angular distribution of scattered intensity measured at constant compositions and different temperature distances from the plait point gave values of 1.50, 0.765, and 0.077, respectively. The results demonstrate the critical exponent renormalization, show first evidence of the nonzero critical exponent η in a three‐component fluid system, and are not inconsistent with the scaling relations. In view of the renormalization which provides us with a stronger temperature dependence on the correlation length ξ, the critical region (K ξ> 1) can be reached even at T − Tc = 0.5°C. Thus, we are able to compare our experimental linewidth and hydrodynamic shear viscosity data with the Kawasaki theory at very large values of K ξ ≃ 50. Our experimental observations agree very well wi...

The critical opalescence of polystyrene—cyclohexane mixtures has been studied by means of small‐angle x‐ray scattering for polystyrene samples of molecular weight 118 000 and 147 000. The upper limit of s/λ (s = 2 sin½θ, where θ is the scattering angle, and λ is the wavelength in the medium) was extended to 0.025 A−1, approximately 50 times greater than the upper limit accessible to visible light. At large values of s/λ, plots of the reciprocal of the intensity vs (s/λ)2 showed downward curvature. The experimental results can be represented by I = [A+B(s/λ)2]−1+C. The magnitude of the ratio of the two terms in the expression representing the intensity is consistent with the conclusion that the constant term C represents the scattering from density fluctuations, and the angular distribution of the scattering caused by concentration fluctuations is accurately represented by [A+B(s/λ)2]−1 over the range of s/λ investigated for the polystyrene—cyclohexane system. However, this is not true for mixtures of ordinary liquids for which the constant term is much too large to be interpreted as a density scattering term.

The particle scattering factor P(ϑ) with Gaussian statistics for polydispersed systems has been treated. For a polystyrene sample with a sharp molecular weight distribution (Mw/Mn < 1.02, Mw = 1.5 X 106), the measured angular dependence of scattered intensity indicates that the polymer coil does obey Gaussian statistics. This holds for a range of concentrations provided the variation of the constant representing the radius of gyration with concentration is adjusted.

The angular and the spectral distribution of scattered light intensity from polystyrene (Mn = 392 000) in cyclohexane were measured at the critical solution concentration very near its critical mixing point in the one phase region. Results show deviations from the critical exponent concept for both static and dynamic thermodynamic properties of critical macromolecular solutions.

Intensity measurements of x rays scattered at small angles by carbon dioxide are reported for various equilibrium states in the critical neighborhood of the temperature–density diagram. From our studies we have observed that (1) the K2 dependence in a plot of reciprocal relative scattered intensity (Is−1) versus scattering angle is obeyed over the following ranges: 2.66 × 10−4 A−2

Critical exponents (γ, ν, β, andμ) of one-component fluid systems from recent experiments show agreement with the universality concept and the critical exponent relations. Variations in the magnitude of exponents from different systems are well within the limits of error of present-day techniques. Thus, it is within reason to expect that observable deviations from universality could come from more complex fluid mixtures, where such a concept may break down, even though, based on published literature values, the prospects remain very small.

Intensity and linewidth measurements of light scattered by the isobutyric acid in water system are reported for various equilibrium states in the critical neighborhood of the temperature-concentration diagram. By extrapolation of these data to zero scattering angle and then to (unrealized) states below the phase separation temperature one may determine a common "pseudospinodal curve" ${T}_{\mathrm{sp}}(X)$ described by ${T}_{\mathrm{c}}\ensuremath{-}{T}_{\mathrm{sp}}(X)\ensuremath{\sim}{|X\ensuremath{-}{X}_{\mathrm{c}}|}^{\frac{1}{{\ensuremath{\beta}}^{\ifmmode\dagger\else\textdagger\fi{}}}}$ where $X$ is the concentration, and we find ${\ensuremath{\beta}}^{\ifmmode\dagger\else\textdagger\fi{}}\ensuremath{\simeq}0.37\ifmmode\pm\else\textpm\fi{}0.04$. As expected on the grounds of the homogeneity hypotheses, the value of ${\ensuremath{\beta}}^{\ifmmode\dagger\else\textdagger\fi{}}$ is essentially the same as the previously observed value of the exponent $\ensuremath{\beta}$ for the coexistence curve. Empirical equations of the form $I_{C,0}^{}{}_{}{}^{\ensuremath{-}1}\ensuremath{\propto}{[T\ensuremath{-}{T}_{\mathrm{sp}}(X)]}^{\ensuremath{\gamma}}$ and $D\ensuremath{\propto}{[T\ensuremath{-}{T}_{\mathrm{sp}}(X)]}^{{\ensuremath{\gamma}}^{*}}$ are used to effect the extrapolations to determine ${T}_{\mathrm{sp}}(X)$. Here ${I}_{C,0}$ and $D$ are the extrapolated zero-angle scattering intensity and the diffusion coefficient, while $\ensuremath{\gamma}$ and ${\ensuremath{\gamma}}^{*}$ are corresponding critical exponents. We show theoretically, however, that a value ${\ensuremath{\beta}}^{\ifmmode\dagger\else\textdagger\fi{}}\ensuremath{\ne}\frac{1}{2}$ is inconsistent with the general validity of these empirical formulas, which should thus be discarded as over-all representations of the variations of $D$ and ${I}_{C,0}$. A tentative test is made of a more general scaling equation for ${I}_{C,0}$ by a convenient plot. Moderate success is obtained. The measurements confirm the exponent values $\ensuremath{\gamma}=1.24\ifmmode\pm\else\textpm\fi{}0.03$ and ${\ensuremath{\gamma}}^{*}=0.67\ifmmode\pm\else\textpm\fi{}0.03$. The distinction between pseudospinodal curves, determined by extrapolation from stable thermodynamics states, and a true spinodal curve which (if it exists) can only be observed by measurements on metastable states, is emphasized.

Taking advantage of the temporal and spatial coherence of laser light, we are able to investigate translational motions relating to transport properties of the system by means of quasielastic light scattering. This spectral distribution of quasielastically scattered light is particularly useful for investigating the dynamics of colloids in suspension or macromolecules in solution. We have tested our self-beating spectrometer by reinvestigating the power spectrum of laser light scattered by suspensions of 0.357-μ diameter polystyrene latex spheres and measured colloidal gold in water to demonstrate the potentials of this technique.

Spores of Fusarium oxysporum, Colletotrichum lagenarium, Aspergillus oryzae, Thielaviopsis basicola and Penicillium atrovenetum were lysed to varying extents in soil, but the spores of A. niger and A. phoenicis were resistant under identical conditions. A streptomycete enzyme preparation which digested F. oxysporum and C. phomoides spore walls and catalysed the release of N-acetylhexosamine and reducing sugars had some effect on walls of Helminthosporium turcicum and an albino strain of Thielaviopsis basicola and little or no effect on spores of a pigmented strain of T. basicola or of other fungi. Ghitinase and β -1,3-glucanase preparations caused little lysis of F. oxysporum conidia, but the addition of a protease enhanced digestion. The release of N-acetylhexosamine and reducing sugars by chitinase and β -1,3-glucanase preparations suggests that F. oxysporum and C. lagenarium spore walls contain chitin and a β -1,3-glucan.

Critical opalescence of a binary liquid mixture, normal perfluoroheptane and iso‐octane has been investigated by light and small‐angle x‐ray scattering over a broad range of s/λ, where s=2 sin (θ/2), λ is the wavelength in the medium, and θ is the scattering angle. The scattering data show that the critical opalescence observed in this system is essentially the same as has been found in other binary liquid mixtures.

Opalescence of a binary liquid mixture, n‐decane and β,β′‐dichloroethyl ether, has been investigated at and near the critical solution concentration over a range of temperatures near the critical solution temperature in the one phase region. Both components were purified by preparative gas chromatography with estimated organic impurities at less than 1 ppm. Corrections for attenuation and density scattering were briefly discussed. It was found that trace impurities (essentially water) did not affect the over‐all molecular interaction range of the principal components. Within the range of the values s/λ [s=2 sin (θ/2),λ= wavelength in the medium, s/λ varied from 1.29×10—4 to 7.46×10—4 A—1] and temperatures studied, the light scattering data were in good agreement with the Debye theory [J. Chem. Phys. 31, 680 (1959)]. The average range of molecular forces (l) was found to be 13.4 A.

For some liquid mixtures, anomalies—for instance, in the coexistence curve—have been observed. Experiments are reported on the angular dissymmetry of visible light as well as on the temperature dependence of the zero‐angle scattering for two liquid mixtures. The mixture methanol‐cyclohexane behaves normally, the other, aniline‐cyclohexane, shows anomalies.

A photometer has been built for fluctuation studies of liquid mixtures near the critical point with thermostats controlled to 0.001°. The instrument has provisions for a choice of light sources and detection systems, and is capable of absolute scattered intensity measurements of dilute polymer solutions over a wide temperature range. It can also be converted to a spectrophotometer with a variable angular acceptance for the phototube, so that the effect of forward scattering on turbidity measurements may be examined.

Measurements by the laser homodyne ``self‐beating'' technique were made of the quasielastic Rayleigh linewidth in a critical binary liquid mixture, isobutyric acid—water (Tc=26.12°C), at temperature distances 0.071°, 0.196°, 0.36°, 0.73°, and 1.16°C above the critical solution temperature over a range of scattering angles. Deviations from the Landau—Placzek theory on the K2(K=ks, k=2π/λ, s=2 sinΘ/2) dependence of the half‐width of the central (Rayleigh) component (T) have been observed. Experimental data are in good agreement with Fixman's modification which takes into account the effect of long‐range correlations in binary liquid mixtures and has the form T=aK2(1+K2/κ2) with κ corresponding to the inverse correlation length of Ornstein and Zernike.

Visible light scattered by binary mixtures of critical concentration of ordinary molecules at small temperature distances above the critical temperature shows an angular dissymmetry which can be related to the range of molecular forces. The theory of critical opalescence is extended to polymer solutions of high molecular weight for which an additional dissymmetry due to the extension of the polymer coil is observed. The range of molecular forces and the radius of gyration at the critical concentration can be determined simultaneously by measurements of the angular dependence of scattered intensity at different temperatures above the critical temperature. Results of experiments on a solution of polystyrene (Mn=2 820 000) in cyclohexane are reported.

In the vicinity of the critical point, angular dissymmetry of scattering is observed. Its amount is connected with the range of molecular forces. Integrated over all angles it reveals that the total scattering is less than that calculated according to Einstein. At the same time the scattered light is less blue than we would expect according to Rayleigh. This effect has been investigated on the system polystyrene‐cyclohexane by measurements of the wavelength dependence of the total turbidity of the solution at its critical concentration as a function of the temperature. The interaction ranges as calculated from the data are in good agreement with values calculated from dissymmetry measurements.

The cloud‐point curve and critical opalescence of the system polystyrene (Mn = 392 000)–cyclohexane have been investigated. The critical point, as determined by the phase‐volume ratio method, is at a higher concentration than the maximum in the cloud‐point curve. Experiments are reported on the angular and the spectral distribution of scattered light for a solution of composition corresponding to the maximum in the cloud‐point curve and on the spectral distribution for a solution of critical concentration. The temperature dependence of the extrapolated zero‐angle scattered intensity obeys a relation lim K→0 IC−1∝(T − Tsp)γ with γ = 1.26 ± 0.08. The long‐range correlation length ξs obeys a relation ξs∝(T − Tsp)−νs with νs = 0.62. The extrapolated linewidth obeys a relation lim K→0 (Γ / K2)∝(T − Tsp)γ* with γ* ≈ 1 at the concentration exhibiting the maximum phase separation temperature (Tp,max), and γ* ≈ 0.77 at the critical solution concentration (Tsp = Tc). The long‐range correlation length of the critica...

A laser homodyne spectrometer with a measurable angular range of 20°-150° and a temperature control of better than f 0.001 OC was interfaced with an IBM 1800 digital computer for direct on-line data acquisition of the angular and the spestral distribution of the scattered intensity from a two-component critical liquid system, perfluoromethylcyclohexane-carbon tetrachloride, near its critical mixing point. Both components were purified by preparative gas chromatography and subsequent vacuum distillation. Special care was taken to select appropriate columns for the separation of impurities and to prevent contamination of the system from moisture. Scattering data were obtained by means of a cylindrical light-scattering cell of 8 mm i. d. and a flat cell with a 1 mm light path. The intensity measurements were obtained using an angular aperture of 1.40 while the linewidth measurements were obtained using an angular aperture of OSO. From our intensity studies we have observed that (1) the K2 dependence in the reciprocal scattered intensity due to concentration fluctuations (1~') is obeyed (2) the temperature dependence of the extrapolated zeroangle scattered intensity which is related to the osmotic coeffjcient (ap/aC)p,~, has the form : lim 1;' cc eY, where E = (T - Te)/Te ; and y is a critical exponent. We have obtained K+O y = 1.15 f 0.02 at the critical solution concentration. The Rayleigh linewidth of the critical mixture was measured at temperatures between 0.006O and 0.715 OC above Tc, for scattering angles 30° 1, we show that r approaches AK3. In the region 0.076 < Kts < 3.75, our data agree quite well with the Kawasaki extended mode-mode coupling theory. Our results show that a direct application of the Kadanoff-Swift-Kawasaki result y* (= y - Y) = v is invalid. However, if we take into account the temperature dependence and anomaly of the high-frequency shear viscosity, then y - Y approaches v and, in the case of isobu- tyric acid in water, y - Y z v. Scaling-law considerations also lead us to question the validity of the relation (sv = 2 - a) or its equivalents sv = y + 2 B and sv = p + v.

A specially designed light‐scattering photometer with a measurable angular range of 15°–140° and with a temperature control of better than 0.001°C was used to study the angular dependence of the scattered intensity from binary critical liquid mixtures, consisting of a homologous series of alkanes as one of the two components, and β,β′‐dichlorodiethyl ether (or chlorex) as the other component. Both components were purified by preparative gas chromatography and subsequent vacuum distillation. Special care was taken to prevent contamination of the systems from moisture. Scattering data were obtained by means of cylindrical light‐scattering cells of different diameters (6 and 8 mm i.d.), detectors of different slit‐widths (one set consisting of two slits: 1 × 10 mm each and 20 mm apart, and the other set: 0.5 × 10 mm each and 20 mm apart) and incident light of different wavelengths (λ0 = 365, 436, and 578 mμ). Phase diagrams for n‐decane–chlorex and n‐dodecane–chlorex were carefully determined in order to pro...

This letter presents a new least‐squares integration method of analysis for time‐dependent correlation functions consisting of two exponentials. It also contains an investigation of the effect of sample time on the accuracy that can be achieved in a given intensity correlation measurement by means of 24‐ and 48‐channel single‐clipped photon‐correlation spectrometers. Comparison is made with the least‐squares normal equation method using experimental as well as simulated results.

The method of correlated temperatures provided a technique for computing the hot channel factor when a maximum fixed, but nonzero, number of hot channels is permitted in a reactor core. This method made adequate allowance for the fact that, of the various indentifiable uncertainties affecting the core, some are global and some are local in nature. A method is provided which has the same objectives as those of the method of correlated temperatures and uses the same formulation, but does away with the Monte Carlo computations of the latter. It is believed that the analytical method provided can be more easily adapted to the computations of hot channel reliability in an actual reactor. (auth)

We report the effects of long‐range correlation for a critical mixture of polystyrene (Mn≈392 000) in cyclohexane at small temperature distances from the phase separation temperature (T − Tp

The angular distribution of scattered intensity and decay times of concentration fluctuations have been measured by means of digital photon counting and single-clipped photon correlation for solutions of Group C meningococcal polysaccharides at 31°C. The z-average diffusion coefficient 〈D〉z and its second moment 〈D2〉z have been determined from the time-dependent correlation function using the cumulant expansion technique. Very low observed values of 〈D〉z and the tremendous width of the polydispersity index, which is the z-average normalized variance, suggest a higher degree of aggregation than the monomer–dimer type self-association at finite concentrations.

Two 20-week experiments were conducted to determine the effects of 0.99, 1.77, 2.55 and 3.33 percent calcium, 0.64 and 0.82 percent total phosphorus and 0 and 0.25 percent Nopgro in diets of breeder turkeys on egg production, fertility, hatchability, egg weight, shell thickness and calcium content of blood serum. Each experiment contained 272 female and 32 male Beltsville White turkeys. Turkeys fed diets containing the lowest level of calcium produced significantly fewer eggs, lower hatchability of fertile eggs and of all eggs set, lower shell weight as percentage of egg weight, thinner egg shells and less egg shell color. Varying the phosphorus level in the diets as indicated above and adding a commercial fermentation product, Nopgro, which is a blend of dried residues produced from Aspergillus oryzae and Bacillus subtilis grown on a wheat bran base, to the diets failed to influence these measurements, except for an increased shell thickness in one experiment from the added phosphorus. Based upon a review of the literature and data collected in this study, the calcium requirement of breeder turkey hens is in excess of 2.0 percent and perhaps as much as 2.5 percent to obtain optimum egg production, and levels of calcium in excess of 2.5 percent are believed not detrimental to hatchability.

MATTERSON et al. (1965) reported a metabolizable energy value of a sample of condensed fish solubles of 2.094 kilocalories per gram (950 kilocalories per pound) of ingredient in chick studies. As far as the authors are aware, this report contains the only metabolizable energy value of condensed fish solubles for poultry based upon experimental results. In addition no published reports of experiments with poultry designed to determine the coefficients of digestibility of the protein and fat in condensed fish solubles have been found. Two experiments were conducted to determine the metabolizable energy value and the coefficients of digestibility of the protein and fat in condensed fish solubles for young turkeys. PROCEDURE Day-old Medium White male poults were placed in starting batteries and fed a practical-type ration (Table 1) ad libitum on June 21 and October 26, 1966. At two weeks of age, the poults were individually weighed. The largest and…

A least‐squares difference‐integration method is described by which a sum or distribution of exponentials can be characterized using moments or cumulants analysis. Comparison of the higher‐order approach with the procedures of Koppel using simulated data at realistic experimental signal‐to‐noise ratios shows definite improvements in the determination of those moments.