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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Open System Neural Networks, Bradley Hatch
Open System Neural Networks, Bradley Hatch
Theses and Dissertations
Recent advances in self-supervised learning have made it possible to reuse information-rich models that have been generally pre-trained on massive amounts of data for other downstream tasks. But the pre-training process can be drastically different from the fine-tuning training process, which can lead to inefficient learning. We address this disconnect in training dynamics by structuring the learning process like an open system in thermodynamics. Open systems can achieve a steady state when low-entropy inputs are converted to high-entropy outputs. We modify the the model and the learning process to mimic this behavior, and attend more to elements of the input …
Development And Application Of New Solid-State Models For Low-Energy Vibrations, Lattice Defects, Entropies Of Mixing, And Magnetic Properties, Jacob M. Schliesser
Development And Application Of New Solid-State Models For Low-Energy Vibrations, Lattice Defects, Entropies Of Mixing, And Magnetic Properties, Jacob M. Schliesser
Theses and Dissertations
Low-temperature heat capacity data contain information on the physical properties of materials, and new models continue to be developed to aid in the analysis and interpretation of heat capacity data into physically meaningful properties. This work presents the development of two such models and their application to real material systems. Equations describing low-energy vibrational modes with a gap in the density of states (DOS) have been derived and tested on several material systems with known gaps in the DOS, and the origins of such gaps in the DOS are presented. Lattice vacancies have been shown to produce a two-level system …
Specific Heat And Thermodynamic Properties Of Metallic Systems: Instrumentation And Analysis, Brian E. Lang
Specific Heat And Thermodynamic Properties Of Metallic Systems: Instrumentation And Analysis, Brian E. Lang
Theses and Dissertations
A small-scale adiabatic calorimeter has been constructed as part of a larger project to study nano-particles and to facilitate specific heat measurements on samples where it is difficult to obtain enough material to run on the current large-scale adiabatic apparatus. This calorimeter is designed to measure sample sizes of less than 0.8 cc over a temperature range from 13 K to 350 K. Specific heat results on copper, sapphire, and benzoic acid show the accuracy of the measurements to be better than ±0.4% for temperatures higher than 50 K. The reproducibility of these measurements is generally better than ±0.25%. Experimental …
A Potentiometric Method, A Convenient And Rapid Technique For Determination Of The Thermodynamics Of Ionization Reactions For Water, Weak Acids, And Some Slightly Soluble Salts In Aqueous Organic Mixed Solvents, Charanai Panichajakul
Theses and Dissertations
A potentiometric method which is devised to be rapid and convenient for determining ionization constants for water, weak acids (or bases), and certain solids in mixed solvents is described. The method has been applied to the determination of ionization for water, acetic acid, benzoic acid, and phenol and the solubility product constant for silver chloride in mixtures of water with methanol, ethanol, acetone, tetrahydrofuran, and p-dioxane containing from 0 to 70 mass percent organic co-solvent at several temperatures between 10 and 40°C. Results are used to study the thermodynamics of ionization in each mixture which is discussed relative to various …
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 …
Thermodynamics Of Charge Transfer Complexes, Reed J. Jensen
Thermodynamics Of Charge Transfer Complexes, Reed J. Jensen
Theses and Dissertations
Charge transfer complexes were studied spectrophotometrically in the liquid state by a modified Benesi-Hildabrand method. TiCl_4 - Benzene and TiCl_4 - diphenyl ether solutions were found to form contact charge transfer complexes, that is complexes with very weak and non-directional interactions. The systems TiCl_4 - anisole and TiCl_4 - diethyl ether form complexes of the types AD and AD_2 where A stands for TiCl_4 and D stand s for the organic donor. The formation constants for the complexes were, for the TiCl_4 - anisole, K_1 = 0.077, K_2 = 0.01; and TiCl_4 - diethyl ether, K_1= 3.0, K_2 = 1.0. …
A Thermodynamic Study Of Complex Formation In Aqueous Solution.|Ni.|Pthe Hg(Ii)-, Zn(Ii)-, Cd(Ii)-, Ag(I)-Serine Systems.|Nii.|Pthe Hg(Ii)-, Zn(Ii)-, Cd(Ii)-, In(Iii)- Thioglycollic Acid System :|Ba Study Of The Effect Of D[Pi]-D[Pi] Bonding On These Complexes, Marriner Lee Morrell
Theses and Dissertations
Thermodynamic equilibrium constants were obtained potentiometrically using a Beckman pH meter for metal-serine and metal-thioglycolloc acid complexes to study the thermodynamic properties of the complexes and the effect of dπ - dπ bonding on the equilibrium constants. The following calculations were made: 1. The stepwise dissociation of protons from serine at 10, 20, 30, and 40°C and the stepwise dissociation of protons from thioglycollic acid at 20, 30, and 40°C. 2. The thermodynamic formation constants for Zn(II), Cd(II), Hg(II), and Ag(I) with serine at 10, 20, 30, and 40°C and at two ionic strengths. 3. The thermodynamic formation constants for …
Thermodynamic Properties Of Water Absorbed On Silica, Conrad V. Hatch
Thermodynamic Properties Of Water Absorbed On Silica, Conrad V. Hatch
Theses and Dissertations
The object of the work presented in this thesis was to obtain quantitative values of the thermodynamic changes in water upon adsorption by silica. Two methods were used. The first was a determination of the differential entropy and heat of adsorption independent of any theory of adsorption. The second method included a new interpretation of the "c" constant of the Brunauer, Emmett, and Teller Theory in which c was expressed in terms of the standard free energy of adsorption. The experimental data gave satisfactory results in determining the differential heat and entropy of adsorption. The results obtained in determining the …
An Electrochemical Determination Of The Thermodynamic Properties Of Silver And Mercury Sulfides, Arthur G. Cole
An Electrochemical Determination Of The Thermodynamic Properties Of Silver And Mercury Sulfides, Arthur G. Cole
Theses and Dissertations
The problem consists of measuring accurately the free energy of formation, heat of formation, entropy, and solubility product constant of silver and mercury sulfides, and is a part of a larger study extending to many other metal sulfides. The confusion now existing in the chemical literature amply justifies a study of this nature. The thermodynamic properties of several important metal sulfides have never been measured, and the only values available for them are estimates. Determinations of the properties of many other metal sulfides have been carried out, but the results given by different authors often differ widely.