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The influences of lubricant viscosity and loading velocity on the surface finish of plastically compressed 6061 aluminum alloy cylinders were studied. Specimens with polished end faces were subjected to compression between two flat, chromium plated dies, with lubricants of a viscosity ranging from 42 cp to 1207 cp at 38 deg C. The deformed surfaces were studied under a scanning electron microscope and by stylus tracings and CLA readings. With the lighter lubricants surface roughening resulted from preferential yielding leading to a clear delineation of grain boundaries and slip lines. With the heavier lubricants, localized “hydrodynamic pockets” formed in addition to the above features. The depth of pockets increased with viscosity and/or velocity.

The neutron irradiated potassium hexacyanoferrate(III) solutions were analyzed for Fe(CN)64−, Fe(CN)63−, and Prussian blue. The retention values (1.1%) were constant throughout the pH and concentration ranges studied, and did not change with the length of irradiation. The complex behavior of the radiochemical yield of the Fe(CN)64− and Prussian blue was attributed to the competition of the various reactions involved in the irradiation.

Oxidation of α-terpineol by atmospheric air resulted twelve products, which seemed more complicated than the results of the previous works. All the products were identified and rationalized. The mechanisms of some minor reactions were discussed.

Mossbauer spectra of K4Fe(CN)6 and K4Fe(CN)6 3H2O, observed 3 weeks after irradiation, did not differ from the unirradiated samples, which implied that there was no change in oxidation state of iron. The fresh aqueous solutions of these irradiated samples also did not show any change in the oxidation state. Fe(OH)3 separated in chemical treatment was time dependent and was further influenced by the chemical reagents.

Mossbauer spectra of irradiated K1Fe(CN)6, observed 3 weeks after irradiation, showed that 3% of iron was converted to Fe(CN)64−, while chemical analysis performed 100 hours after irradiation showed 18% was reduced to Fe(CN)64−, Prussian blue was isolated in the chemical analysis, but not observed in the Mossbauer spectra. The Prussian blue formation was found to be time dependent.

The paper describes the disk machine designed and constructed for the investigation of the traction in elastohydrodynamic line contacts for two synthesized hydrocarbon fluids. The results of this experimental study are presented and compared with the theoretical predictions of traction according to the thermal and non-Newtonian theory recently presented by the authors (1). Presented as on American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference held in Atlanta, Georgia, October 16–18, 1973

Mossbauer and ir spectroscopies have been applied to the study of radiation effect on Fe11X(CN)3 (X=NO+, NH3, H2O, NO2−, SO3=) and Fe111X(CN)3 (X=NH1, H2O, NO2−). Fe(II) complexes were not oxidized to Fe(III), whereas Fe(III) complexes were reduced to Fe(II). Na2[FeNH3(CN)3]·H2O was partially reduced at 7 hour irradiation, but [FeNO(CN)2]= was obtained at the longer irradiations due to the replacement of H by O produced by water radiolysis.

Neutron irradiation was carried out on 0.2, 0.4 and 0.7 M solutions of potassium hexacyanoferrate(II) at the pH range of 2-10. Fe(CN)51− was found when pH

Oxidations of α-cadinol, T-cadinol, T-muurolol and δ-cadinol with SeO3 gave corresponding ketols and diols. Reductions of the ketols with NaBH4 gave epidiols. NMR data of these sixteen compounds are compared.

In this paper, a recent solution on the thermal-elastohydrodynamic lubrication of rolling and sliding cylinders is extended to consider a more rigorous analysis of temperature by using a two-dimensional finite difference method. The effect of the local pressure-temperature dependent viscosity, the compressibility effect of the lubricant and the heat from compression of the lubricant are considered in the solution of the Reynolds and the energy equations. Two series of results were obtained. The first is a heavily loaded series intended to correlate with Crook's experimental results, and the second is a moderately loaded series intended to correlate with experimental data (15). These results show that temperature has a moderate influence upon the shape of the pressure and film profile, but very little effect upon the magnitude of the film thickness in the contact zone. The frictional force, however, is strongly influenced by the temperature rise in the film. Crook's experimental film thickness data and tho...

On NaY and HY, aromatic compounds are selectively adsorbed in preference to paraffins and naphthenes. Smaller aromatic compounds are adsorbed in preference to larger aromatic compounds. All the compounds studied can be sorbed into the pore structure of the zeolites and the selectivies are primarily a reflection of relative affinity for the zeolite and steric effects rather than a sieving effect.

Most analyses on a circular coil when used in the eddy current method for nondestructive testing are empirical. Theories based on simple models are often inadequate to account for some experimental observations when the spacing between the coil and the material became small. In the present paper this problem is formulated as a boundary value problem. Wave equations of the magnetic vector potential are solved. The change in the coil impedance, when placed above a semi-infinite medium, is obtained by means of the induced voltage method, which is shown to depend only on the ? component of the magnetic vector potential. This change in impedance is found to be dependent on a number of factors: the shape and size of the coil; the spacing between the coil and the metal; the thickness, conductivity, and composition of the material, etc. Numerical computations are discussed for a few selected materials in connection with experimental results obtained elsewhere. The comparison made lent support to the present analysis. Extension of this method to the case of a stratified media is included.

The governing equations for the dynamical system of a self-acting gas-lubricated journal bearing are formulated. An approximate solution for the equilibrium position of the journal center is obtained by use of Galerkin’s method. The equilibrium solution shows close agreement with the exact numerical computer solution obtained by Elrod. The stability of the equilibrium solution is investigated by solving the linearized equations on an analog computer. The solution of the set of linearized equations shows that there exists a threshold speed of instability for each equilibrium position. The value of this threshold speed is presented in a stability chart. In addition, approximate particular solutions for the nonlinear dynamical equations are obtained by use of the analog computer. The results are shown as trajectories of the journal center when it is displaced arbitrarily from the equilibrium position.

One of the most important considerations in designing a high-speed, gas-lubricated, self acting journal bearing is the instability of the journal under a given operating condition. Intensive research in this direction has led to a number of significant contributions in the past five years. The present paper extends the method of Cheng and Trumpler to study the stability of plain cylindrical gas journal bearings of finite length. Both equilibrium and stability results were obtained.

The binding of succinate and perfluorosuccinate to the supernatant and mitochondrial isoenzymes of aspartate transaminase has been studied using 1H and 19F nuclear magnetic resonance (NMR) as probes. The binding was measured for the pyridoxal (El) and pyridoxamine (Em) forms of the holoenzyme, the apoenzyme, and the pyridoxal form after reduction of the internal Schiff's base with NaBH4 (reduced holoenzyme). The NMR parameters studied were band broadening or chemical shift changes upon dicarboxylic acid binding to the enzyme. The dissociation constant values of succinate and perfluorosuccinate for the active forms of each isozyme, El and Em, are in the 1 to 4 mm range. Kd values of the inactive forms of the supernatant transaminase for perfluorosuccinate are 18.3 mm, reduced form, and 12.0 mm, apoenzyme form. Anions are competitive with dicarboxylic acid binding and, because of mutual exclusion, do not alter the correlation time, τc of bound succinate. This competition allows for the calculation of the chloride affinity of the pyridoxal, Kd = 9 mm (supernatant), 3 mm (mitochondrial), and pyridoxamine forms, Kd = 5 mm (supernatant), 1.6 mm (mitochondrial), of each isoenzyme. Because amino acids and glutarate also compete with perfluorosuccinate binding in the El, Em, and apoenzyme forms, it is concluded that dicarboxylic acids bind to these forms of the enzyme and that amino acids can form complexes with the pyridoxamine form. The correlation time of bound dicarboxylic acid shows an increase, i.e. more restricted segmental motion of succinate, with decreasing pH and is particularly critical in the pH 5 and pH 8 regions. The fastest correlation time of perfluorosuccinate (greatest segmental motion) corresponds to that bound to the reduced holoenzyme. The above effects agree with the competition-pH dependence between dicarboxylic acids and anions. Since there is evidence of the active center histidyl residue as the anion binding site (Cheng, S., and Martinez-Carrion, M. (1972) J. Biol. Chem. 247, 6597–6602) and of the Schiff's base nitrogen as the low pH ligand of a carboxyl group in glutaric acid (Jenkins, W. T., and D'Ari, L. (1966) J. Biol. Chem. 241, 5667), a proposal for the binding of dicarboxylic acids is made. Dicarboxylic acids inhibit because they form a bridge between the active center histidyl residue and the pyridoxal phosphate internal aldimine with the e-amino group of a lysyl residue. Thus, the binding subsites for a competitive inhibitor such as succinate, although structurally similar to the substrates, differ from the productive mode of binding of the amino or keto acids which form covalent enzyme-substrate complexes.

8 Lowell, H. EL, "Tables of the Bessel-Kelvin Functions Ber, Bei, Ker, Kei and Their Derivatives for the Augument Range 0(0.01)107.50," 1959, NASA. 9 Tsui, E. Y. W., "Bending Characteristics of Tapered Cylinders," Journal of Spacecraft and Rockets, Vol. 3, No. 6, June 1966, pp. 889-893. 10 Tsui, E. Y. W., "Analysis of Tapered Conical Shells," Proceedings of the Fourth U.S. National Congress on Applied Mechanics, Vol. II, 1962, pp. 807-816. 11 Tsui, E. Y. W., "Bending of Tapered Plates," Journal of Spacecraft and Rockets, Vol. 3, No. 6, June 1966, pp. 876-880. 12 Stern, P. and Tsui, E. Y. W., "On the Bending of Spherical Shells," Proceedings of the American Society of Civil Engineers, Journal of Engineering Mechanics Division, Vol. 92, EM3, June 1966, pp. 53-66. 13 Bushnell, D. and Hoff, N. J., "Influence Coefficients of a Circular Cylindrical Shell with Rapidly Varying Parabolic Wall Thickness," AIAA Journal, Vol. 2, No. 12, Dec. 1964, pp. 21672173. 14 Baker, B. R. and Cline, G. R., Jr., "Influence Coefficients for Thin Smooth Shells of Revolution Subjected to Symmetric Edge Loads," Journal of Applied Mechanics, Vol. 29, 1962, pp. 335-339. Galletly, G. D., "Bending of 2:1 and 3:1 Open-Crown Ellipsoidal Shells," Bulletin Series 54, 1959, Welding Research Council. 16 Fliigge, W., Streses in Shells, Springer-Verlag, Berlin, 1962. 17 Reissner, E., On the Theory of Thin Elastic Shells, H. Reissner Anniversary Volume—Contributions of Applied Mechanics, Edwards, Ann Arbor, Mich., 1949, pp. 231-247.

In this paper we explore the Vlasov conjecture on the relationship between bifurcation points and phase transitions. Because of the availability of the exact results of Ruelle, we focus our attention on the Kirkwood‐Salsburg hierarchy, and recognizing that the first equation in this hierarchy is of the form of a Lichtenstein‐Lyapunov nonlinear operator equation, we use a fundamental theorem of Krasnosel'skii to determine, under a suitable closure, bifurcation points for the same system considered by Ruelle. A special example is treated—that of a one‐dimensional system of hard rods— and our main conclusion follows from the results of this study: namely, that ``in this one‐dimensional system'' the bifurcation point does not seem to be related to the onset of a phase transition.

The relative importance, with respect to load-carrying capacity, of each geometrical parameter in a self-lubricated thrust bearing, with an enclosed pocket, is examined at Λ = 0.55. The bearing geometries, including the pocket configurations, for three types of film profiles are optimized. The film profiles in the pocket considered are flat-step, tapered, and taper-step, Fig. 1. Of these three profiles of film, the taper-step film, in an enclosed-pocket bearing, offers the best load-carrying capacity. The variations of load versus each geometrical parameter are shown graphically to facilitate design procedure. These results are obtained from the solution of Reynold’s equation for a compressible fluid film as approximated by the finite-difference method [5]. The load-carrying capacity of an enclosed-pocket bearing with taper-step profile can be significantly higher than that of a bearing with the spiral-grooved pattern under the conditions investigated.

Rates of Counterdiffusion are markeldy affected not only by the critical molecular diameter of the diffusing molecules but also by other physicochemical properties of the liquids and the nature of the cation in the zeolite. The effective diffusivity in NaY or HY under counterdiffusion conditions is less by a factor of 10−1 to 10−3 than that for unidirectional diffusion into an initially empty pore structure.

A theoretical analysis of the buckling problems of heterogeneous aeolotropic cylindrical shells under combined axial, radial, and torsional loads is presented. Four boundary conditions at each end of the cylinder are satisfied for the case of both ends hinged or that of both ends clamped. Classical thin shell theory of small deflection is followed. Because only six elastic coefficients are required out of the usual 21 for a general aeolotropic body, it is possible to solve Flugge's differential equations of equilibrium by assuming suitable functions for the displacements of the middle surface. By the superposition of these solutions, a general solution that satisfies the boundary conditions can be reached. If the thin shell is laminated from layers of different materials, the resultant forces and moments of an element are integrated from layer to layer by considering that the six elastic coefficients are piecewise continuous. Orthotropic and isotropic materials are particular cases of this analysis.

The isothermal, elastohydrodynamic (EHD) solutions in the inlet region of line contacts are extended to cover the full range of pressure-viscosity parameter, G, and the region of extremely heavy loads. The effect of a composite exponential model for the pressure-viscosity dependence on the film thickness is also studied. Results of the film thickness are compared with those based on work by Grubin, Dowson-Higginson, Bell and Kannel, and Herrebrugh. Comparison is also made between the theoretical results with the recently obtained X-ray film thickness measurements.

In this paper, the pressure generation and static stability of face-type seals are discussed and an expression is developed to estimate the effectiveness of hydrodynamic action in these seals. Some design data are presented for the hydrostatic step seal, hydrostatic-orifice compensated seal, hybrid spiral-groove seal, and the shrouded Rayleigh step seal. These data are applicable to large-diameter seals for compressible fluids. The seal ring distortions due to initial imperfection, pressure, and thermal expansion are discussed. Approaches to estimate and to minimize the effects of these distortions are outlined. Finally, the ability of a face seal to track the vibrations of the runner is also discussed and methods required to determine the dynamic tracking for rigid or flexible seals are described.

The pressure and deformation profiles between two colliding lubricated cylinders are obtained by solving the coupled, time-dependent elastohydrodynamic equations with an iterative procedure. The analysis includes several effects which were not considered in a previous solution by Christensen [4], namely, the effect of surface velocities due to local deformation, the effect of the lubricant compressibility, and the effect of a lubricant with composite pressure-viscosity coefficients. It is found that the local approach velocity plays an important role during final stages of normal approach. It causes the lubricant to be entrapped within the contact region, and both the pressure and deformation profiles appear to converge to the Hertzian profile. The use of a smaller pressure-viscosity coefficient at high pressures reduces the sharp pressure gradient at the center of the contact, and produces a much milder variation of load with respect to the film thickness. The effect of compressibility of the lubricant is found to be relatively small.

Es wird das thermoelastische Spannungsfeld in einem Halbraum erhalten, erzeugt durch eine willkurlich verteilte, sich langs des Randes gleichformig rasch bewegenden Warmequelle. Dabei wird angenommen, dass Warme aus dem elastischen Halbraum durch Konvektion abgeleitet wird. Es wird die zweidimensionale entkoppelte Theorie verwendet. Als Beispiel wird ein Problem der elasto-hydrodynamischen Schmierung betrachtet.

A nummerical solution to the coupled Reynolds, elasticity, and energy equations for the pressure, temperature, and film thickness between two heavily loaded rolling and sliding cylinders is obtained. The analysis of the energy equation is based on a mean viscosity across the film. Results for a thermal case with a slip ratio of 0.25 as well as an isothermal solution are presented. Pressure peak is found near the exit of the film for cases with or without thermal effects and the influence of the temperature on the film thickness is moderate.

IN a recent paper on population policy, Glen G. Cain concludes that the ". . . feasibility of attaining a benign rate of population growth ... rests on limited scientific evidence." 1 In this paper, we attempt to add to our store of knowledge concerning population growth by estimating a simultaneous equation model of birth rates in the United States. Our model is based on time-series data for the United States covering the 1910 to 1968 period and consists of four separate equations: a birth rate equation, a permanent income equation, an infant mortality equation, and a female labor participation rate equation. Two variants of the total model are reported; the first is based on the two-stage regression procedure and the second variant is based on three-stage least squares. In both cases, elasticity multipliers are computed as a guide to policy decision making. In general, the two approaches yield quite similar results; nevertheless, there are some differences therefore, the dual approach. Our data are generally unadjusted and should therefore reflect both secular and cyclical patterns. The major exception to this rule is our use of permanent rather than measured income for reasons outlined below.

The structure of δ-cadinol was established as amorphan-3-ene-9β-ol (VIII) by chemical behavior and spectroscopic data.

Pronounced effects of thermal treatment on the properties of graphite fiber/ polycarbonate and glass fiber/polycarbonate composites have been demonstrated and explained. At 20 volume percent loading of random-in-a-plane, discontinuous fibers, both specimen strength and modulus in both fiber systems were found to increase dramatically upon molding above 260-265 C, whereas only the graphite system was further improved by subsequent annealing. In the latter case, property improvement is due to generation of a crystalline inner layer at the interface, which apparently transfers the stresses more effectively from fiber to fiber. Regardless of the type of fiber, molding at 275 C (slightly above 260-265 C, the melting point of crystalline polycarbonate) results in improved properties due to better wetting of the fibers by the resin. Hot forming of graphite reinforced polycarbonate composites between the molding and annealing steps takes advantage of the higher process-ability of the unannealed material in addition to providing increased modulus and strength in the final molded article.

A numerical solution of the elastohydrodynamic film thickness in an elliptical contact is developed. The two-dimensional Reynolds’ equation in the inlet region is solved by a finite-difference method. The deformation contour in the inlet region is calculated according to the classical Hertz theory for elliptical contacts. Results are presented as side leakage film reduction factors, which are defined as the ratios of the film thickness of the finite contact to that calculated by a line contact theory based on the same maximum Hertz stress. The results obtained for a b/a → ∞, which corresponds to a line contact, and for b/a = 1, which corresponds to a circular contact, agree with those obtained in [2]. Comparison with experimental data [1] indicates that this theory predicts a film thickness slightly higher than those measured by the experiment.

From the wood of Taiwania cryptomerioides Hayata, two new sesquiterpenes, cadinan-3β, 9β-diol and cadinan-3β, 9α-diol were isolated as minor components. Their structures were elucidated as (I) and (II), respectively.

Quantitative gas chromatographic analyses supplemented by X-ray diffraction studies of the adsorption of ethanol and acetone (as model polar organic compounds) on homoionic montmorillonite revealed marked variation in the number of molecules associated with each exchange cation. The results show increasing association in the order K+ +2+2+. K+ and Na+ associate with two and three molecules, respectively, of either ethanol or acetone, and the resulting complexes expand to form a monolayer (∼13 Å). Ba2+ and Ca2+ form both monolayer complexes as well as double layer complexes. In the single layer complexes Ba2+ associates with either four molecules of ethanol or four molecules of acetone, Ca2+ associates with five molecules of ethanol or four molecules of acetone. In the double-layer complexes the observed cation-molecule ratios are 1 : 8 for both Ba2+-ethanol and Ba2+-acetone, 1 : 10 for Ca2+-ethanol, and 1 : 8 for Ca2+-acetone.The striking dependence of ethanol and acetone adsorption on the nature of the exchangeable cation suggests that cation-dipole interactions play an important role in the adsorption process. Structural models of the organic complexes are presented.

The effects of collisions on the scattering function of a two‐component fully ionized gas are discussed, using an improved Brownian motion type collision model. In the collision model, the particle numbers as well as the energy and the linear momentum are conserved; and the electron‐ion collisions are taken into account. The dispersion relations are discussed in detail, and explicit calculations are carried out for the scattering function and the energy‐loss function in the long wavelength approximation when the wavelength is greater than the mean free path and the Debye length. The damped plasma oscillations dominate the energy‐loss function; while for the scattering function thermal diffusions and sound propagations dominate the low frequency region and contribute most to the total scattering cross section. The contribution from the damped plasma oscillations to the scattering becomes important only for high frequencies near the plasma oscillation frequency.

Vibration of the seal ring induced by the axial pulsation, wobbling and initial distortion of the rotor surfaces in a face-seal assembly consisting of a seal ring and a carrier are analyzed. The analyses are divided into two parts: a rigid body analysis dealing with vibrations due to the axial pulsation and wobbling; and an elastic ring analysis dealing with vibration induced by the initial surface waviness of the rotor. The fluid film characteristics are approximated by linear springs having two direct and two cross-coupling spring stiffnesses in the transverse and angular directions with negligible damping. Results are obtained in terms of natural frequencies and influence coefficients characterizing the response of the seal ring to the rotor motion. Presented at the 23rd ASLE Annual Meeting in Cleueland, May 6–9, 1968

Phosphorescence has been observed in a highly purified fluid solution of naphthalene in 3‐methylpentane (3‐MP). The phosphorescence lifetime of C10H8 in 3‐MP at −45°C was found to be 0.49 ± 0.07 sec, while that of C10D8 under identical conditions is 0.64 ± 0.07 sec. At this temperature 3‐MP has the same viscosity (0.65 CP) as that of benzene at room temperature. It is believed that even these long lifetimes are dominated by impurity‐quenching mechanisms. Therefore it seems that the radiationless decay times of the lowest triplet states of simple aromatic hydrocarbons in liquid solutions are sensibly the same as those in the solid phase. A slight dependence of the phosphorescence lifetime on solvent viscosity was observed in the temperature region, −60° to −18°C. This has been attributed to the diffusion‐controlled quenching of the tiplet state by a residual impurity, perhaps oxygen. Bimolecular depopulation of the triplet state was found to be of major importance over a large part of the triplet decay. Th...

Cholesterol-4-14C and b-sitosterol-4-14C were incorporated into cigarettes and their presence in mainstream smoke was studied. The transfer of 14C-labelled cholesterol to mainstream smoke was 20.27 %, of which 16.25 % was in trapped smoke condensates and 4.02 % in butts; only 0.004 % was in ashes. The transfer of 14C-labelled b-sitosterol to mainstream smoke was 16.20 %, of which 13.11 % was in trapped smoke condensates and 3.09 % in butts; only 0.007 % was in ashes. The relative composition of free sterols, steryl esters, and bound glycosides in cigarette tobacco and in trapped smoke condensates was also studied. Fractions of free sterols and steryl glycosides were higher while fraction of esters was lower in trapped smoke condensates as compared to cigarette tobacco. Comparison of four individual sterols (cholesteroI, campesterol, stigmasterol and b-sitosterol) was studied in cigarette tobacco and cigarette smoke (smoke condensates, butts, wrapping papers from butts). A slight increase of cholesterol was noted in smoke condensates and wrapping papers from butts.

The effects of anions on substrate binding to the mitochondrial and supernatant isozymes of aspartate transaminase (EC 2.6.1.1) have been studied by direct spectrophotometric titrations of the active site-bound pyridoxal phosphate. The binding affinity of both isozymes for amino and dicarboxylic acids is dependent on the type and concentration of buffer anions. At high physiological pH, the substrate dissociation constants are proportional to the anion concentration. At low pH, substrate binding to the enzyme involves the displacement of more than one anion. The anions act as competitive inhibitors of the substrates and are thought to occupy the positively charged sites at the isozymes' active center where the substrate(s) carboxyl group(s) bind. Of all the anions studied, the order of inhibition was benzoate g chloride g acetate g phosphate g cacodylate. The comparison of the dissociation constants of the enzyme-substrate complexes for the mitochondrial and supernatant isozymes confirms that, although there is competition between the anions and the substrates or dicarboxylic acid inhibitors for the active center of the enzyme, the anion independent dissociation constants for substrates and inhibitors are intrinsically different in each isozyme. The various buffer anions also affect the pK of the active site-bound pyridoxal phosphate chromophore in different ways. Instead of the pK values of 6.3 previously reported for the mitochondrial and supernatant chromophore in chloride or phosphate buffers (high affinity anions), a pK of 5.4 can be measured for both transaminases with cacodylate buffers (low affinity anions). Thus, the binding of anions results in a pK shift of the chromophore to higher pH. This shift seems to be more pronounced the higher the affinity of the enzyme for the anion. Anions also act as competitive inhibitors for the second half of the transamination, the conversion of the pyridoxamine enzyme to the pyridoxal enzyme. The anion-binding affinities of the pyridoxamine enzyme are higher than those for the pyridoxal enzyme in both supernatant and mitochondrial transminases. Thus, a given anion concentration will affect unequally the apparent affinity of the pyridoxal form for amino acid and of the pyridoxamine form for keto acid. Since in general, the mitochondrial enzyme shows a higher anion affinity than the supernatant isozyme, whether in the pyridoxal or pyridoxamine form, the anion competition with substrates at any given concentration will be greater for the mitochondrial isozyme. The mechanistic schemes of either isozyme of aspartate transaminase must, therefore, include anion effects. Besides the obligatory enzyme substrate intermediates, there must be complexes such as pyridoxal enzyme-anion and pyridoxamine enzyme-anions in equilibrium mixtures of aspartate transaminase, substrate(s), and buffers.

The blue color of condensed oxygen is mostly derived from double transitions. This paper presents a theoretical calculation of the intensity of the double transition (a 1Δg) (a 1Δg)←(X 3Σg−) (X 3Σg−), using a model based on a pair of oxygen molecules at a fixed separation of 3.81 A. The intensity enhancement is assumed to be derived from the mixing (a 1Δg) (a 1Δg)∼∼(X 3Σg−) (B 3Σu−) and (a 1Δg) (1Δu)∼∼(X 3Σg−) (X 3Σg−). Matrix elements for these interactions are calculated using a π‐electron approximation for the pair system. Good molecular wavefunctions are used for all but the perturbing B 3Σu− state, which is approximated in terms of ground‐state orbitals. The largest contribution to the matrix elements arises from large intramolecular terms multiplied by intermolecular overlap integrals. The strength of the interaction depends not only on the intermolecular separation of the two oxygen molecules but also, as expected, on the relative orientation. Matrix elements are calculated for different orientatio...

In the last evolutionary stage of certain massive stars, there occurs, at the temperature of 4×109−5×109 oK, a chain of nuclear reactions by means of which He nuclei regenerated by the dissociation of heavier elements are disintegrated into free nucleons. The most probable nuclear reaction chain, as indicated by calculations, is as follows: He4(α,p) Li7, Li7 (α, 2α) H3, H3(p, n) He3, He3(β −)H3, H3(t, 2n) He4. The net result of the reaction chain is the equation, He4(2β −) 4n with an energy absorption of 29.2 MeV per He nucleus disintegrated. The nuclear process is so rapid at the temperature and density considered that the star undergoes simultaneously a catastrophic collapse and a gigantic explosion during which the nuclear process is completed and the neutrons are expelled out and decay spontaneously into protons. The regeneration of hydrogen in the last evolutionary stage of massive stars is regarded as having astrophysical significance. It appears that supernovae are mainly initiated by this process. The abundance of hydrogen in the gases ejected by dense stars, the most abundant distribution of hydrogen in the universe among all elements, etc. may be explained on this basis.