Search

Estimated values of Wilson parameters depend upon the objective function which is used in the optimization procedure. The relationships between these estimated parameters seem to be more important than the values themselves, and the desirable paired parameters are confined to a region near ridge lines. This region represents a high level of joint confidence. In this study four different objective functions were used in the investigation of binary and ternary systems. Also, comparisons were made on calculated V/L equilibrium values predicted for ternary systems by using parameters estimated from binary and from the sole use of ternary data. Using the parameters estimated from binary data with a chosen objective function did not produce the best sum of squares of errors in a ternary system for the same objective function. Based on the overall performance, the best objective function to fit parameters in three ternaries is the one to fit the pressure. Les valeurs d'estimation des parametres de Wilson dependent de la fonction objective qu'on emploie dans la methode d'optimisation; les relations entre ces parametres qu'on evalue semblent plus importantes que les valeurs měmes, et les parametres desirables, groupes par deux, sont confines a une region situee pres des lignes de l'arěte, laquelle represente un degre eleve de fiabilite. On a employe, dans le present travail, quatre fonctions objectives differentes pour etudier des systemes binaires et tertiaires. On a aussi fait des comparisons relativement aux valeurs d'equilibre calculees V/L, qu'on avait prevues pour les systemes ternaires au moyen de parametres evalues a partir des donnees sur les systemes binaires et de celles des systemes ternaires seulement. L'emploi des parametres evalues partir des donnees sur les systemes binaires n'a pas produit la meilleure somme de carres d'erreur dans un systeme ternaire pour la měme fonction objective. En se basant sur le rendement global, la meilleure fonction objective qui convient aux parametres dans trois systemes ternaires est celle qui convient a la pression.

A numerical method is developed to simulate the temperature progression of freezing a food system. It is assumed to have a constant density and to be macroscopically homogeneous during the freezing operation. The simulated results are compared with the measured temperature progression in the center of a beef slab immersed in a-39°F bath.

The results of capillary thermal transpiration measurements for nitrogen, oxygen, carbon monoxide, methane, methyl chloride, hydrogen sulfide, and sulfur dioxide over a (mean) temperature range of 408.6 to 501.3°K are reported. The problem that arises in interpreting the data to obtain thermal transport information is carefully considered. While this difficulty is not completely resolved, our data for the nonpolar gases are combined with our earlier results and used to compute smoothed values of the rotational relaxation numbers and Eucken factors for the temperature range 165–500°K.

The in vitro reduction and oxidation of the isomeric methylcyclohexanones and methylcyclohexanols by horse liver alcohol dehydrogenase, in the presence of NADH2 or NAD has been studied. The enzymic reactions closely resemble the corresponding in vivo metabolic conversions and support the view that the oxido-reductase in the animal body is similar to liver alcohol dehydrogenase. The findings are discussed in terms of the conformations of the alcohols and ketones and a correlation of the observed rates, Km values, and the steric specificity supports the view that the in vivo inversion of the thermodynamically less stable alcohols (±)-cis-2-, (±)-trans-3-, and cis-4-methylcyclohexanol could occur through a ketone intermediate.

A rigorous and simple thermodynamic equation relating equilibrium vapor-liquid compositions and the phase enthalpy differences for a binary, isobaric system is extended to multicomponent systems. An analysis is made to indicate the potential applications of computing the latent heat of vaporization directly from the isobaric vapor-liquid equilibrum data and testing the consistency of phase composition and enthalpy data.

Measurements of in situ oxide film growth on polycrystalline titanium alloys in pure oxygen at one atmosphere pressure were made by the ellipsometric method. Alloys contained 0 to 23 wt.% aluminum and the test temperature range was 165° to 270°C. For the thin film region (less than 40 A at 330°C and 200 A at 550°C), the data follow the reciprocal logarithmic kinetics model.

1. (+/-)-2-, (+/-)-3- and 4-tert.-Butylcyclohexanone are reduced in the rabbit to secondary alcohols, which are excreted extensively conjugated with glucuronic acid. 2. The major metabolite of (+/-)-2-tert.-butylcyclohexanone is (+)-cis-2-tert.-butylcyclohexanol, which has been isolated from the urine as [(+)-cis-2-tert.-butylcyclohexyl beta-d-glucosid]uronic acid. The minor metabolite is (+)-trans-2-tert.-butylcyclohexanol. 3. (+/-)-3-tert.-Butylcyclohexanone is reduced mainly to (+/-)-cis-3-tert.-butylcyclohexanol, and to a smaller extent to (+/-)-trans-3-tert.-butylcyclohexanol. 4. 4-tert.-Butylcyclohexanone yields mainly the trans-alcohol, which is excreted in conjugated form and has been recovered from the urine as (trans-4-tert.-butylcyclohexyl beta-d-glucosid)uronic acid. The cis-alcohol is formed to a minor extent and excreted in conjugated form. 5. The ratios of the amounts of cis- to trans-alcohols produced by the three ketones differed from the relative amounts of cis- and trans-alcohols produced by the corresponding methylcyclohexanones. 6. From these findings the suggestion is made that two orientations of ketone relative to coenzyme occur: alcohols with an equatorially orientated hydroxyl group are thought to be produced as a result of a ;face-to-face' interaction with NADH, and alcohols with axially orientated hydroxyl groups as a result of a ;perpendicular' interaction. Which will predominate is thought to depend on steric factors, particularly the size and position of alkyl substituents in the substrate.

Using an integral representation of the Hermite polynomial and then Gaussian quadrature, very accurate representations are obtained for exp ⁡ ( − z 2 ) , erf ( z ) \exp ( - {z^2}),{\operatorname {erf}}(z) , and arcsin ⁡ ( z ) \arcsin (z) .

Metal surfaces of titanium, aluminum, copper, lead, and zinc were irradiated by a 25 joules pulsed laser with an energy flux ranging from 106 to 108 cal./(sq.cm.) (sec.). The resulted cavities were sectioned, polished and measured to compare with the isotherms computed from several heat conduction models. Reasonable agreement was found between the experimental cavity diameters at the interface and those calculated from the disk source model. Also, a graphical correlation between the cavity depth and its interface diameter is presented.

1. The seven isomeric optically inactive forms of methylcyclohexanol (i.e. 1-, and cis- and trans-2-, -3- and -4-) are excreted by rabbits mainly as glucuronides of the thermodynamically more stable forms of the alcohols. The eighth isomer, cyclohexylmethanol, however, undergoes aromatization in vivo, giving rise to benzoic acid and hippuric acid. The (+/-)-2-, (+/--3- and 4-methylcyclohexanones are reduced in the rabbit and excreted mainly as the glucuronides of the thermodynamically more stable forms of the corresponding methylcyclohexanols. 2. Racemic cis- and trans-2-methylcyclohexanol and 2-methylcyclohexanone are all excreted as conjugated trans-2-methylcyclohexanol. However, when the (+/-)-cis-alcohol or the (+/-)-ketone is fed, (+)-trans-2-methylcyclohexanol is excreted, whereas when the (+/-)-trans-alcohol is fed it is excreted as the (+/-)-trans-alcohol. 3. Racemic cis- and trans-3-methylcyclohexanol and 3-methylcyclohexanone are all excreted as conjugated racemic cis-3-methylcyclohexanol. cis- and trans-4-Methylcyclohexanol and 4-methylcyclohexanone are all excreted as conjugated trans-4-methylcyclohexanol. 4. The metabolic differences between the various methylcyclohexanols are explicable in terms of their conformations and of Vennesland's (1958) hypothesis of the role of NADH in dehydrogenation reactions.

A focused laser pulse of 5 × 10 −4 sec duration and less than 2 cal energy output was used to ignite titanium powder compacts in oxygen. A mathematical model based on energy transport in a disk source was formulated to obtain a temperature profile by numerical integration, A nondecreasing sensible heat content of the solid phase was used as the ignition criterion. The model was found valid for porosity within 0.214–0.32 and for pulse energy flux below 20,000 cal/cm 2 -sec.

10. taneous conduction and radiation in an absorbing medium, J. Heat Transfer 88C, 63-12 (1962). R. VISKANTA and R. J. GROSH, Effect of surface emissivity on heat transfer by simultaneous conduction and radiation, Int. J. Heat Mass Transfer 5, 129-134 (1962). W. LICK, Energy transfer by radiation and conduction, Proc. Heat Transfer and Fluid Mechanics Institute, pp. 1426. Stanford University Press, Stanford (1963). R. GREII, Energy transfer by radiation and conduction with variable gas properties, Int. J. Heat Mass Transfer 7, 891-900 (1964). YAN-PO CHANG, A potential treatment of energy transfer in a conducting, absorbing, and emitting medium. ASME Paner 61-WAiHT-40 (1961). L. A. TARSHIS, S. ‘O’HARA and R. VISK~NTA, Heat transfer by simultaneous conduction and radiation for two absorbing media in intimate contact, Int. J. Heat Mass Transfer 11, 333-341 (1969). R. VISKANTA, Heat transfer by conduction and radiation in absorbing and scattering materials, J. Heat Transfer 87C, 143-150 (1965). D. H. TIMMON~ and J. 0. MINGLF., Simultaneous radiation and conduction with specular reflection, AIAA 6th Aerospace Sciences Meeting, Paper No, 68-28, New York (1968). W. LICK, Transient energy transfer by radiation and conduction, Int. J. Heat Mass Transfer& 119-121(1965). A. S. HAZZAH and J. V. BECK, Unsteady combined conduction-radiation energy transfer using a rigorous differential method, Int. J. Heat Mass Transfer 13, 511-522 (1910). 11.

A numerical method and graphs of generalized solutions are presented for a moving interface problem of freezing a saturated liquid inside a cylindrical or a spherical container with a constant heat transfer coefficient, as well as melting a saturated solid. The frozen solid phase has a constant heat capacity.

An improved method is presented to measure the latent heat of vaporization of volatile liquids at atmospheric pressure on a differential scanning calorimeter. Individual measurement errors of 8–10-mg samples were reduced to less than 2% and the average error of five runs on benzene and toluene was less than .01%.

A graphical procedure, using velocity-vector diagrams, is suggested for determining the coefficients ∂S/∂pn, where S represents the output displacement of a linkage and pn are parameters (dimensions) of the linkage. These coefficients appear in a design procedure used by Svoboda on the 4-bar linkage. It is suggested that his procedure may prove useful in the design of more complex linkages.

W I T H T H E ADVENT of nuclear reactors and high temperature technology, liquid metals have found an increasing number of applications. Also, they represent a unique class of relatively simple solutions of atoms and their agglomerates. Therefore, a study of their vapor pressures and related thermodynamic properties is of interest from both theoretical and practical grounds. Behavior of metal solutions may be studied by measuring electric potentials between the liquid metal solution of interest and a reference electrode or by measuring vapor pressure of solutions. Usual methods of measuring vapor pressure require an elaborate set-up and are time-consuming. The present work used a simple apparatus ( I ) and shortened the experimentation time ( 4 ) . A slight decrease of precision is therefore expected. Maximum errors in measured temperature and pressure here are respectively 0.5"C. and 2 mm. of Hg. These errors are caused mainly by pressure fluctuations of solution in the neighborhood of its bubble point. The binary system studied in this work consists of a volatile component (mercury) and a relatively non-volatile component (tin). Vapor pressure data of this system a t 324" C. are available ( 2 ) but that a t other temperatures are not. This work presents experimental data a t temperatures below 324" C. and shows temperature effect on solution behvavior or deviation from ideality.

A flexible graphical technique is presented to synthesize a four-bar linkage with an adjustable fixed pivot to satisfy a specified angle between two straight line segments traced by a coupler point.

A systematic method of calculating and presenting the results of consistency tests is given and illustrated on the methane-ethane system in the space of −140 to 60°F and 100 to 700 psia. The results indicate incompatibility of error levels between isobars and isotherms. Also, different arrangements of terms in the thermodynamic differential equations were sometimes found to produce different levels of inconsistency for the same space. Results are analyzed and discussed. On decrit une methode systematique de calculer et de presenter les resultats des essais de consistance; on l'illustre dans le cas du systeme methane-ethane sur une echelle de pressioas absolues de temperature de −140°F 60°F et une echelle de pressions absolues de 100 a 700 livres au pouce carre. Les resultats obtenus indiquent une inconciliabilite des degres d'erreur entre les isobares et les isothermes. On a aussi trouve quc parfois differentes dispositions des termes dans les equations differentielles therniodynamiques produisaient differents degres d'inconsistance pour la meme echelle. On analyse les resultats obtenus et les discute.

Adult sheep were prepared to receive total nutriment by dual infusions. Volatile fatty acids were infused intraruminally and glucose, vitamins, and amino acids via jugular cannula. Methionine and glycine were varied to provide isonitrogenous amino acid infusion with levels of 0, 0.75, 1.50, 2.25, 3.00, 3.75, 4.50, 5.25, and 6.00 g of methionine/day. Urinary nitrogen (UN), plasma urea nitrogen (PUN), urinary urea nitrogen (UUN), and nitrogen balance (NB) responded curvilinearly to increased methionine infusions. The point at which a tangent to the curve had a slope of zero was taken as the level at which methionine was no longer limiting. This occurred at infusion levels of 4.81 to 5.00 g/day. Plasma methionine increased sharply at infusion levels of 3.63 g/day. Most plasma amino acids were influenced by levels of methionine infusion with nonessential amino acids being higher when methionine was limiting or in excess. Plasma insulin and plasma glucose were also influenced by level of methionine infusion with plasma insulin responding in a manner similar to PUN, UN, UUN, and NB. J. Nutr. 104: 1646-1656, 1974.

The dissolution rates of cholesterol in model bile salt solutions are controlled by diffusion in slowly flowing bile and by interfacial kinetics in rapidly flowing bile. At low flow, dissolution varies with the square root of bile flow and can be predicted, a priori , from existing correlations of mass transfer. At high bile flow, dissolution is independent of bile flow and is probably dominated by the rate of micelle adsorption. These results show that cholesterol gallstone dissolution, a potential nonsurgical therapy for cholelithiasis, can be accelerated little in slow bile, but more significantly in rapidly flowing bile.

1. When [U-(14)C]methylcyclohexane is fed to rabbits (dose 2-2.5m-moles/kg. body wt.), 65% of the radioactivity is excreted in the urine as metabolites, 0.5% appears in the faeces and about 15% in the expired air, some 4-5% remaining in the body in about 60hr. after dosing. The 15% of the dose appearing in the expired air consists of unchanged methylcyclohexane (10%) and (14)CO(2) (5%). The low output of (14)CO(2) shows that reactions leading to complete oxidation of methylcyclohexane are of minor importance. 2. The main metabolite found in the urine was the glucuronide of trans-4-methylcyclohexanol which was isolated. Seven methylcyclohexanols were found in the urine as conjugated glucuronides. The amounts of these were determined by isotope dilution to be as follows: cis-2-, 0.6%; trans-2-, 1.2%; cis-3-, 11.5%; trans-3-, 10.5%; cis-4-, 2.4%; trans-4-methylcyclohexanol, 14.7%, cyclohexylmethanol, 0.3%. No 1-methylcyclohexanol was found. There was evidence also that a small amount (approx. 1%) of the hydrocarbon aromatized to benzoic acid, probably via cyclohexylmethanol and cyclohexane-carboxylic acid. 3. The pattern of hydroxylation and the various amounts of the isomers found suggest that the hydroxylation in vivo of methylcyclohexane is dependent on steric factors in the molecule, hydroxylation occurring to the greatest extent at the carbon atom furthest away from the methyl group.

Computer results of the required time to freeze completely a pure liquid in a container shaped like a slab, a cylinder or a sphere are correlated by equations which converge to the asymptotic solutions of the problem. Variables are grouped into dimensionless parameters so that these equations are applicable to any given system.