DDT in its own right and as a typical representative of that class of insecticides now known as chlorinated hydrocarbons has proved one of our most important and interesting insect toxicants. Its mode of action though extensively studied still eludes us. [...]

No description available.

Proefschrift--Faculteit der wiskunde en natuurwetenschappen en die der genesskunde--Leiden--universiteit, 2003. / Bibliogr. p. 164-165.

Texte remanié de: Diss.--Leipzig, 1920. / Bibliogr. p. 92-99.

Th. 3e cycle--Toulouse, 1984. / Bibliogr. p. 609-618. Notes bibliogr. Index.

Diss. Pharm. Bern. / v. Bern.

This thesis presents a computer program written (in Fortran IV) to simulate the steady state off design point performance of virtually any gas turbine configuration (dealing primarily with aerospace applications). The performance is calculated using component characteristic maps for compressors, combustion chambers, turbines (both compressor turbines and free turbines) and a map giving the velocity coefficient for exhaust nozzles. The off design point performance is determined by using a modified Newton-Raphson method. Cont/d.

A theoretical and experimental examination into the dynamics of granular solids has been completed which covers aspects of flow and failure within this material. The investigation is divided into three natural sections; each section being devoted to a different type of failure. As indicated by the title, the subject of the study was cohesionless soil, and thus the basic tenets of soil mechanics and the failure of granular media are applicable. The first section deals with gravity flow of non-cohesive granular material in both axial and rectangular geometry. Traditional plasticity theory is used to establish characteristics of stress and strain, also stress sliplines within a wedge. From these, two relationships between the angle of internal friction and the bound to a radial flow field are established. A minimum energy theory of flow is discussed and then used to determine mass flow rates. From this theory a velocity profile is deduced an by use of either the entire profile or the vertical ray or the extreme angular ray three relationships between the bound tot he radial flow field and the mass flow rate are established. The limits to piping in axial symmetry are defined. It is shown that gravity flow in rectangular geometry must always result in pipes. Experiments were devised to substantiate these findings and they show that, dependent upon the assumptions that were made, the devised relationships bracket, within reasonable limits, the radial bound and the mass flow rate. Work of two other investigators is compared wit the presented experimental results. The definitions of pipe are shown to have validity. Section Two was the result of an attempt to measure a parameter that was relevant to the investigation in Section Three. The possibility of the passive rather than the active lateral earth pressure acting upon a shifting retaining wall was discovered while attempting the measurement of the coefficient of friction of sand on mild steel. The third section is concerned with an investigation into the factors that affect the forces on a horizontally propelled model that is immersed in sand. The parameters of depth, speed, projected model area, and other model characteristics were varied, and experimental relationships between the force and these parameters determined. Also, pressure measurements were made within the sand as the model passed to determine the extent of the failure region. Several other experiments, such as the effect of false walls on the force level, were made in order to determine the limits of validity of the main experiment. It was found that the force on the model varied as the 2.3 power of the depth, linearly with the projected model area, and not at all with model surface, model length, or speed in the range 0-15 feet per minute. The pressure measurements and false-walls studies showed that failure occurred within the sand and not at the walls of the tank; also that failure took the form of successive shear dislocation of pyramidally shaped wedges of sand.

This thesis presents a computer program written (in Fortran IV) to simulate the steady state off design point performance of virtually any gas turbine configuration (dealing primarily with aerospace applications). The performance is calculated using component characteristic maps for compressors, combustion chambers, turbines (both compressor turbines and free turbines) and a map giving the velocity coefficient for exhaust nozzles. The off design point performance is determined by using a modified Newton-Raphson method. Cont/d.

The compounds 12-phenoxy-dodecane-1-thiol, 4-dodecyloxymercaptophenol and 3-dodecyloxymercaptophenol have been synthesized using a novel synthesis to investigate the effect that the orientation of the functional group has on surface acidity. 3-dodeycloxymercaptophenol and 4-dodecyloxymercaptophenol differ in that the hydroxyl group is substituted on different carbons of the benzene ring. The difference in substitution patterns should present the hydroxyl group in different orientations in the interface between a self-assembled monolayer of the compound and aqueous solutions buffered over a pH range of 3-13. By preparing self-assembled monolayers of these molecules on gold substrates, the ability of the hydroxyl group to donate its proton was shown to depend on the hydroxyl group substitution pattern on the benzene ring through contact angle titration experiments. 3-dodecyloxymercaptophenol clearly showed plateaus at low and high pH with a broad transition between the two plateaus. 4-dodecyloxymercaptophenol showed a clear plateau at low pH but not at high pH, although a transition was observed. Using infrared spectroscopy, it was further shown that the long molecular axis of the benzene ring in 3-dodecyloxymercaptophenol was tilted from the surface normal by 55°. The short molecular axis of the ring was twisted out of the plane of the surface by 28° for self-assembled monolayers of this molecule on gold substrates. In contrast, the tilt angle of 4-dodecyloxymercatophenol was measured to be 46° and was twisted out of the surface plane by 36°. It was also found from cyclic voltammetry experiments in 0.5 M KOH, that the ionized monolayers of 4-dodecyloxymercaptophenol were 2.3 kJ/mol less stable than monolayers of 3-dodecyloxymercaptophenols. This finding suggests that hydrogen bonding and other intermolecular interactions in 4-dodecyloxymercaptophenol are greater than in 3-dodecyloxymercaptophenol. / Ph. D.