Excess enthalpies of binary mixtures of 2-ethyl-1-butanol with hexane isomers

Molar excess enthalpies, measured at 298.15 K in a flow microcalorimeter, are reported for binary mixtures of 2-ethyl-1-butanol with the five isomeric hexanes. The results are compared with previously published excess enthalpies for mixtures of 1-hexanol and 2-methyl-1-pentanol with the same hexane isomers.     

On cubic graphs which are irreducible for nonorientable surfaces

Let ∑?_n denote the nonorientable surface of nonorientable genus n. A graph G is irreducible for ∑?_n if G does not embed in ∑?_n but any proper subgraph does embed. Let I₃∑?_n) denote the set of cubic irreducible graphs for ∑?_n. This note provesTheorem. I₃(∑?_n) is finite for eachn.     

A procedure for obtaining quantum mechanical transformation of diagonalization from the classical

Using as an example two coupled harmonic oscillators, a transformation to normal coordinates is made using the classical-type simultaneous diagonalization of quadratic forms, and this is then used to develop a procedure for constructing the corresponding quantum mechanical transformation to normal coordinates. The total classical transformation is nonunitary, whereas the quantum mechanical is unitary as it has to be in order to satisfy Von Neumann's theorem. Since the classical transformation has definite steps and is a very straightforward procedure, this could be a very useful procedure for constructing the quantum mechanical transformation in many models, and/or an alternative method for many models.     

A further link(s) with inequivalent representations in quantum field theory

In recent years it has become more apparent how useful inequivalent representations of the CCR and CAR in quantum field theory may be in describing and explaining physical phenomena, and several properties and concepts have been stated, referred to, and/or developed in the literature on these ideas. In this paper, some of these are reviewed, and some further properties and concepts are developed as further links in understanding these inequivalent representations in quantum field theory. One of these is a statement as to what actually breaks down in some field theories in the transformation between representations which are unitarily inequivalent. This is developed using the language and ideas of point quantum mechanical invariance, since this should be more familiar to a much larger number of physicists. Also, a statement on state expectation values is developed which can be used as a criterion for the occurrence of inequivalent representations of the CCR and CAR in field theories.     

Thermodynamics of aqueous mixtures of nonelectrolytes II. Isobaric heat capacities of water-n-alcohol mixtures at 25°C

Excess isobaric heat capacities of binary mixtures of water with methanol, ethanol, and 1-propanol were obtained from flow microcalorimetric measurements at 25°C over the entire composition range. The results are compared with those of previous investigations.     

Radical processes in the pyrolysis of acetylene

The literature on the pyrolysis of acetylene below 1000 K is reviewed and it is shown that the reaction is a radical chain polymerization initiated by H atoms. The induction period is examined and shown to arise from a rapid autocatalysis produced by the very first product, vinyl acetylene. Data from studies of acetylene polymerization induced by vinyl acetylene and styrene are examined and shown to be in good qualitative agreement with the radical chain process presented. Measured and where needed, estimated rate constants are given to produce numerical estimates of chain length, rates of polymerization, induction period, and rates of initiation. It is further shown that all the products of the polymerization are capable of efficiently initiating chains in the system. An examination of the possible kinetics of vinylidene shows that it does not play any role in acetylene chemistry.     

Order and disorder in algebraic combinatorics

Text of a plenary address given to the Canadian Mathematical Society at their annual meeting at the University of Waterloo in December 1990. The author’s work is partially supported by grants from the National Science Foundation.