Promotion of dropwise condensation of ethyl alcohol, methyl alcohol, and acetone by polytetrafluoroethylene

Coating condensing surfaces with thin layer of nonpolar Teflon results in dropwise condensation of polar organic vapor. Greater heat transfer coefficients are produced increasing effectiveness of condensing system. Investigation shows that vapors with strong dipole moment tend to condense dropwise

Preliminary investigation of effects of exposure to sulfur hexafluoride on tensile and yield strengths of aluminum and steel

Effects of sulfur hexafluoride on tensile and yield strengths of aluminum and steel with application to exhaust gases from rocket engine

The Factorisation of Chemical Graphs and Their Polynomials: A Polynomial Diyision Approach

Recent advances in computational methods allow the Characteristic and Acyclic Polynomials of a Chemical Graph to be calculated easily. A consequence of this is that checking for a zero-value remainder after computer assisted polynomial division is sometimes the simplest way of testing suspected factors of a chemical graph. The technique is simple enough to apply on a routine basis when characteristic or acyclic polynomials need to be solved. Among appropriate choices for test are linear polyenes and rings, because their roots are already independently available in closed form and they do occur as factors in a significant number of structures. Examination of an arbitrary set of structures showed that the acyclic polynomials of non-cyclic structures tend to be the most easily factorisable, followed by characteristic polynomials of cyclic structures and (least easily factorisable) the acyclic polynomials of the same cyclic structures

Remarks Upon Recognising Genus and Possible Shapes of Chemical Cages in the Form of Polyhedra, Tori and Klein Bottles

Some of the problems associated with recognising and classifying cage structures are reviewed briefly and discussed. Some new structures are considered, including Klein bottles (polyhex and azulenoidl and \u27neal\u27 polyhex double tori

Compiling an Adjacency Matrix of an Arbitrary Structure

An experimental project on which work continues intermittently is the development of an interactive Personal-Computer program to assist in the capture of connectivity information about an arbitrary chemical graph of moderate size. (By arbitrary we mean one that does not fall, or is not recognized as falling, into a class which has useful symmetries or easily applicable analytic formulae to provide short cuts.) The approach is to deal with a graphics-screen image using a small set of tools, in the hope of being able to obtain a connection table faster and with a smaller risk of errors than by manual methods alone. It is applicable both to planar structures and to non-planar ones that have been cut to give a 2D representation

Condensed phase reactions in M-2 double-base propellants at low pressures

Low pressure condensed phase reactions in double base propellant combustio

The Desktop Muon Detector: A simple, physics-motivated machine- and electronics-shop project for university students

This paper describes an undergraduate-level physics project that incorporates various aspects of machine- and electronics-shop technical development. The desktop muon detector is a self-contained apparatus that employs plastic scintillator as a detection medium and a silicon photomultiplier for light collection. These detectors can be used in conjunction with the provided software to make interesting physics measurements. The total cost of each counter is approximately $100.Comment: 29 pages, 14 figure

Atomic Hydrogen Cleaning of Polarized GaAs Photocathodes

Atomic hydrogen cleaning followed by heat cleaning at 450$^\circ$C was used to prepare negative-electron-affinity GaAs photocathodes. When hydrogen ions were eliminated, quantum efficiencies of 15% were obtained for bulk GaAs cathodes, higher than the results obtained using conventional 600$^\circ$C heat cleaning. The low-temperature cleaning technique was successfully applied to thin, strained GaAs cathodes used for producing highly polarized electrons. No depolarization was observed even when the optimum cleaning time of about 30 seconds was extended by a factor of 100