Physical Sciences and Mathematics Commons^™

Ultraviolet Radiation Effects On Rotifers, Syed Asim Hussain

Masters Theses & Specialist Projects

The purpose of this investigation was to study ultraviolet radiation effects on rotifers. The rotifer studied was Philodina acuticornis odiosa Milne. Isolation cultures were used to grow the rotifers individually in separate U-plate depressions. The source of ultraviolet radiation consisted of four mercury germicidal lamps used in combination to deliver a uniform flux of 315 uW/cm² over the sample. Five groups of rotifers, one control and four experimental groups of 96 each, were used. The rotifers used were 2-10 hours of age at the beginning of the experiment. The experimental groups were exposed to uv radiation for 3 minutes, …

Ultraviolet Excitation Thermoluminescence Of Lead-Manganese Calcium Carbonate, Dennis Schrope

Masters Theses & Specialist Projects

Calcium carbonate with impurities of lead and manganese have produced measurable thermoluminescence (TL) when excited by ultraviolet (uv) radiation. In this investigation the lead impurities comprise the majority of trapping centers stimulated by uv irradiation. In addition, centers associated with the CO₃groups have been found to be capable of absorbing uv and ultimately producing TL. The 2537 Å mercury line is primarily responsible for stimulating these centers, and the response was found to be linear to 0.6734 joules/cm².

The thernoluminescence response was discovered to be dependent on the concentrations of lead and manganese. However, for a …

Anion Assisted Redox Rates Between Cobalt (Ii) - Cobalt (Iii) Polypyridyl Complexes In Acetophenone, Seyed Garmestani

Masters Theses & Specialist Projects

The effects of ionic strength and various anions on the rate of electron transfer between tris(2,2'-dipyridine) cobalt(III) and bis(2,2',2"-tripyridine) cobalt(II) complexes have been examined in acetophenone. The redox rate was found to increase with increasing ionic strength in both the presence and absence of added salts. The reaction was first order with respect to each reactant and second order overall in all cases. The influence of the C10₄, BF₄, and B(C₆H₅)₄ anions on the reaction rate was studied with their order of effectiveness being: C10₄- > BF₄ >> B(C_{6 …}

Geomorphology And Land Use Of A Tropical Wet-Dry Environment Santander, Columbia, Joseph Ray

Masters Theses & Specialist Projects

This study deals with the Holocene environmental dynamics experienced by a seasonally wet-dry landscape of tropical Columbia. In light of a high ecological sensitivity, the study area is also analyzed as the resource of man. This is done by intensive study area reconnaissance, mapping, altimeter survey, and radiocarbon dating of fluvial landforms. Also, samples of soil, pasture, and water were collected for later study, and several interviews were completed with local residents.

The study area is a tropical lowland of northcentral Columbia at about 7 ½° north latitude. A maximum local relief about 600 m is maintained by a rather …

Electronic Transitions Of Metal Complexes With Triphenylphosphine As A Ligand, Thomas Zimmer

Masters Theses & Specialist Projects

The spectra of transition metal complexes with triphenylphosphine have been measured near 260 nm and the results interpreted in terms of perturbation of the it electron system of the phenyl ring. All complexes studied show sou degree of delocalization of the d-orbital electrons of the metal into the phenyl ring. However, for first row transition metals, the primary affect was found to be polarization of the phenyl ring due to the presence of the metal ion. For second and third row transition metal ions, the primary effect was found to be metal-ligand back-bonding. However, the effect of polarization of the …

A Spectrophotometric Equilibrium Study Of Nickel(Ii)-3, 4', 4", 4'"-Tetrasulfophthalocyanine, Stephen Lowery

Masters Theses & Specialist Projects

There have been several studies made on the effects of various central metal ions on the aggregation of tetrasulfonated Phthalocyanine dye complexes in aqueous solution, but there have been no studies made on the aggregation of the nickel(II)-4, 4', 4", 4'"-tetrasulfoohthalocyanine (Ni^II-TSPC) complex. Therefore, a study of the effects of nickel(II) on the aggregation of its aqueous tetrasulfonated Phthalocyanine dye complex was Proposed so that a comparison might be made with nrevious studies of central metal ion effects. It was found, however, that Ni^II-TSPC gives a much higher degree of aggregation in water than the metal …