Molecular mechanics calculations of tin-bis (triphenylphosphine oxide) complexes

The capability of molecular mechanics for modeling the wide distribution of bond angles and bond lengths characteristic of coordination complexes was investigatecl. This was the preliminary step for future modeling of solvent extraction. Several tin-phosphine oxide COrnI)le:){es were selected as the test groUl) for t.he d,esired range of geometry they eX!libi ted as \-vell as the ligands they cOD.tained r Wllich were c\f interest in connection with solvation. A variety of adjustments were made to Allinger's M:M2 force·-field ill order to inl.prove its performance in the treatment of these systems. A set of u,nique force constants was introduced for' those terms representing the metal ligand bond lengths, bond angles, and, torsion angles. These were significantly smaller than trad.itionallY used. with organic compounds. The ~1orse poteIlt.ial energ'Y function was incorporated for the M-X l')ond lE~ngths and the cosine harmonic potential erlerg-y function was invoked for the MOP bond angle. These functions were found to accomodate the wide distribution of observed values better than the traditional harmonic approximations~ Crystal packing influences on the MOP angle were explored thr"ollgh ttle inclusion of the isolated molecule withil1 a shell cc)ntaini11g tl1e nearest neigl1'bors duri.rlg energy rninimization experiments~ This was found to further improve the fit of the MOP angle.

Molecular mechanics calculations on some phosphine oxide metal complexes in aqueous and organic solvents

Molecular mechanics calculations were done on tetrahedral phosphine oxide zinc complexes in simulated water, benzene and hexane phases using the DREIDING II force field in the BIOGRAF molecular modeling program. The SUN workstation computer (SUN_ 4c, with SPARK station 1 processor) was used for the calculations. Experimental structural information used in the parameterization was obtained from the September 1989 version of the Cambridge Structural Database. 2 Steric and solvation energies were calculated for complexes of the type ZnCl2 (RlO)2' The calculations were done with and without inclusion of electrostatic interactions. More reliable simulation results were obtained without inclusion of charges. In the simulated gas phase, the steric energies increase regularly with number of carbons in the alkyl group, whereas they go through a maximum when solvent shells are included in the calculation. Simulated distribution ratios vary with chain length and type of chain branching and the complexes are found to be more favourable for extraction by benzene than by hexane, in accord with experimental data. Also, in line with what would be expected for a favorable extraction, calculations without electrostatics predict that the complexes are better solvated by the organic solvents than by water.

Draft Mechanics Resolution, ca. 1836

An unsigned, undated draft of a resolution by Mechanics in the Kingston, Ont. area responding to the availability of cheap convict labour. The resolution proposes to shift convict labour to the Marmora, Ont. iron fields.

Haswell's Engineers' and Mechanics' Pocket-Book

The book is bound in a leather case with a clasp in the front. Inside is printed "S.D. Woodruff, St. Catharines, C.W." in the front of the book and there is a label which says "Band, 74 De Vere Gardens, Toronto 20, Ontario". A full text version of this book is available at the following link: https://archive.org/details/haswellsengineer00hasw

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of September

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of September.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for sundry work for the month of September

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for sundry work for the month of September.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of October

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of October, Oct. 15, 1857.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of October

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of October, Oct. 31, 1857.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway on permanent way for sundry work for the month of October

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway on permanent way for sundry work for the month of October.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of November 30

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of November 30, 1857.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of December

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for repairs of track and sundry work for the month of December, Dec. 1857.

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for locomotive repairs and sundry work for the month of December

Pay roll voucher for foremen, mechanics and laborers of the Welland Railway for locomotive repairs and sundry work for the month of December, Dec. 31, 1857.

Does Chance hide Necessity? : a reevaluation of the debate ‘determinism - indeterminism’ in the light of quantum mechanics and probability theory

Dans cette thèse l’ancienne question philosophique “tout événement a-t-il une cause ?” sera examinée à la lumière de la mécanique quantique et de la théorie des probabilités. Aussi bien en physique qu’en philosophie des sciences la position orthodoxe maintient que le monde physique est indéterministe. Au niveau fondamental de la réalité physique – au niveau quantique – les événements se passeraient sans causes, mais par chance, par hasard ‘irréductible’. Le théorème physique le plus précis qui mène à cette conclusion est le théorème de Bell. Ici les prémisses de ce théorème seront réexaminées. Il sera rappelé que d’autres solutions au théorème que l’indéterminisme sont envisageables, dont certaines sont connues mais négligées, comme le ‘superdéterminisme’. Mais il sera argué que d’autres solutions compatibles avec le déterminisme existent, notamment en étudiant des systèmes physiques modèles. Une des conclusions générales de cette thèse est que l’interprétation du théorème de Bell et de la mécanique quantique dépend crucialement des prémisses philosophiques desquelles on part. Par exemple, au sein de la vision d’un Spinoza, le monde quantique peut bien être compris comme étant déterministe. Mais il est argué qu’aussi un déterminisme nettement moins radical que celui de Spinoza n’est pas éliminé par les expériences physiques. Si cela est vrai, le débat ‘déterminisme – indéterminisme’ n’est pas décidé au laboratoire : il reste philosophique et ouvert – contrairement à ce que l’on pense souvent. Dans la deuxième partie de cette thèse un modèle pour l’interprétation de la probabilité sera proposé. Une étude conceptuelle de la notion de probabilité indique que l’hypothèse du déterminisme aide à mieux comprendre ce que c’est qu’un ‘système probabiliste’. Il semble que le déterminisme peut répondre à certaines questions pour lesquelles l’indéterminisme n’a pas de réponses. Pour cette raison nous conclurons que la conjecture de Laplace – à savoir que la théorie des probabilités présuppose une réalité déterministe sous-jacente – garde toute sa légitimité. Dans cette thèse aussi bien les méthodes de la philosophie que de la physique seront utilisées. Il apparaît que les deux domaines sont ici solidement reliés, et qu’ils offrent un vaste potentiel de fertilisation croisée – donc bidirectionnelle.