Physical Sciences and Mathematics Commons^™

A Real-Time Approach To Process Monitoring Of Heavy Metals: Spectrophotometric Characterization And Application Of Novel Azo, Joseph Timothy Labeots

Theses and Dissertations

I will describe studies in developing an on-line system for process monitoring that is based upon spectrophotometric methods. Heavy metals that are discarded into the environment may pose severe threats to public health, and are thus heavily regulated. Currently, there is no reasonably affordable, reliable, real-time monitoring method for heavy metals in water. This lack of feedback for industrial applications often leads to wasted resources due to massive overtreatment to avoid costly penalties. Spectrophotometry is a viable analysis option assuming a suitable sensor molecule is available as seemingly conflicting requirements may occur. Characterization of the sensor is one of the …

Cooperative Lewis Pairs Based On High-Valent Early Transition Metal Halides And Synthesis Of Their Nitride Complexes, Md. Mamdudur Rahman

Theses and Dissertations

Herein, we report the activation of relatively strong C–H and C–O bonds under mild conditions by a cooperative interaction of TaCl5 and PPh3. An unprecedented activation of nitrile adducts of high-valent transition metals with the formation of novel zwitterionic imido complexes was observed. The scope of the reaction includes a range of substituted unactivated nitriles including the C–H bond activation of both aliphatic and aromatic nitriles.

The cooperative action of a Lewis acidic high-valent transition metal halide (TaCl5 or NbCl5) and a weakly nucleophilic base (NEt3 or PPh3) leads to the deprotonation of a coordinated nitrile and subsequent rearrangement to …

Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum

Theses and Dissertations

Continuing improvement in the field of AM of metals provides the opportunity for direct fabrication of aerospace parts. AM was once used in large part for rapid prototyping but improvements in technology and increases in the knowledge base of AM materials has provided the opportunity for manufacture of AM parts for operational use. The ability to create low numbers of unique parts without having to invest in expensive tooling provides great economic incentive to utilize this technique. IN718 is the most common high temperature alloy used in the aerospace industry and lends itself readily to formation by LPBF. The superior …

Metals On Titania/Hopg As Models For Heterogeneous Catalysts, Randima Piyumalie Galhenage

Theses and Dissertations

The work done in this thesis is mainly focused on understanding the nanoscale morphology and activity of model heterogeneous catalysts. In order to do this we design and prepare model catalytic surfaces in ultrahigh vacuum (UHV) and study these surfaces using electron and ion based microscopies and spectroscopies. The nucleation, growth and chemical activity of mono and bimetallic clusters on TiO₂(110) were investigated in order to understand how activity is influenced by cluster sizes, interactions with the oxide support and surface compositions of the bimetallic clusters. For example, Au-based and Pt-based bimetallic clusters such as Co-Au, Co-Pt, and …

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …

The Thermodynamics Of Transition Metal Chelation In Dilute Aqueous Solution.|Ni.|Pthe Thermodynamics Of Interaction Of Serinate Ion With Divalent Co, Ni, Cu, Zn, And Cd Ions In Aqueous Solution.|Nii.|Pthe Calorimetric Standardization Of Dilute Ferrous Ion Solutions For Use In Determining 2,2'-Bipyridine, Joseph Willard Richards

Theses and Dissertations

Calorimetrically determined ΔH° values are given for the stepwise formation of chelate species between serinate ion and the divalent metal ions of Co, Ni, Cu, Zn, and Cd. These values of ΔH° are compared with those reported in the literature and were combined with values of ΔG° (log K) found in the literature to calculate values of ΔS°. These values of ΔG° and ΔS° are listed also. A new method of standardizing dilute ferrous ion solutions is reported. This procedure makes use of the thermometric titration technique to detect the equivalence point for the reaction of K_2Cr_2O_7 with ferrous ion. …

The Thermodynamics (Log K, [Delta]H°, [Delta]S°, [Delta]Cp°) Of Metal Ligand Interaction In Aqueous Solution.|Ni.|P Design And Construction Of An Isothermal Titration Calorimeter.|Nii.|Pthe Interaction Of Cyanide Ion With Bivalent Nickel, Zinc, Cadmium And Mercury.|Niii.|Pthe Interaction Of Glycinate Ion With Bivalent Manganese, Iron, Cobalt, Nickel, Copper, Zinc And Cadmium, Harlin Dee Johnston

Theses and Dissertations

A new isothermal titration calorimeter has been designed to facilitate the study of heats of reaction and heats of solution at constant temperature. With this calorimeter, endothermic or exothermic processes can be studied at temperatures constant to ±0.0002°C. Heat effects are compensated by balancing the heat effect of the process taking place in the calorimeter against a variable heat and a constant cooling Peltier device. The calorimeter was tested by measuring the heat of ionization of water and the heat of dilution of aqueous HClO_4 solutions. For these systems heats were measured to an accuracy of ±0.02 calorie. Log K, …

Thermodynamics Of Metal-Ligand Interactions In Solution I. The Thermodynamics Of Metal-Cyanide Interaction ; Ii. Application Of The Entropy Titration Technique To Metal-Ligand Systems ; Iii. Log K, [Delta]H And [Delta]S Values For The Interaction Of Sulfate Ion With Metal Ions ; Iv. Interaction Of Mercuric Cyanide With Thiourea In Water-Ethanol Solvent Mixtures, Delbert J. Eatough

Theses and Dissertations

Log K values, valid at zero ionic strength are reported for the interaction in aqueous solution of CN- with Ni2+ and Hg2+ at 10°, 25° and 40°C, and with Pd2+ at 25°C. ∆H° and ∆S° values valid at zero ionic strength and 25°C are also reported for the interaction of CN- with Hg2+ and for the reaction Pd(CN)42- + CN- = Pd(CN)53-. In connection with the study of Pd2+ - CN- interaction, log K values for the hydrolysis of Pd2+ to give PqOH+ and Pd(OH)2 and an E° value for the reaction Pd(s) = Pd2+ + 2e- are reported. A …