Engineering Commons^™

Dynamics Of Stress Induced Hydride Formation In Vanadium, Alex Aning, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Oxygen Activity Dependence Of The Electrical Conductivity Of Li‐Doped Cr2o3, R. F. Huang, A. K. Agarwal, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The electrical conductivity of Li‐doped Cr₂O₃ was investigated as a function of PO₂, temperature, and dopant content. Results show that the electrical conductivity remains almost unchanged with decreasing P O₂ in the high‐P O₂ region but decreases rapidly at low P O₂. A second phase was found in samples which contained more than 0.85 mol% Li. The results are explained by a model in which the concentration of charge carriers is dependent on the acceptor dopant and oxygen vacancy concentration. Copyright © 1984, Wiley Blackwell. All rights reserved

Non-Linear Oscillation, Automodulation And Anelasticity, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

The auto modulation observed in the course of internal friction is discussed as a special example of the universal nature of non-linear oscillations. Universal features of non-linear oscillations are the requirement of energy supply or negative damping and the period doubling route to chaos. The negative damping responsible for the auto modulation is described in terms of the soliton model for twinning deformation. © 1984 The Japan Society of Applied Physics.

Thermogravimetric And Electrical Conductivity Studies Of Mg-Doped Lacro₃ And La-Doped Srtio₃, Brian Keith Flandermeyer

Doctoral Dissertations

"Mg-doped LaCrO₃ and La-doped SrTiO₃ are perovskite compounds that display electrical conductivity which is a function of partial pressure of oxygen (po2). It has been proposed that acceptor-doped LaCrO₃ becomes highly resistive at low po2's due to ionic compensation of the acceptor-dopant present by oxygen vacancies. SrTiO₃ has been thought to absorb O₂ into a crystallographic shear structure and exsolve strontium vacancies which can then ionically compensate the La present and give a high resistance at high po2's.

Given these models, relationships between weight loss and conductivity vs. po₂ are developed for both these …

The Effects Of Certain Impurities And Their Interactions On Zinc Electrowinning, Donald R. Fosnacht, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The effects of germanium, antimony, arsenic, cobalt, glue, and free acid concentration were studied on both commercial and synthetic electrolytes. The effects of a single factor and the combined effects of multiple factors were elucidated. The temperature, zinc concentration, and current density were varied for some of the tests. It was found that the acid content was the most critical factor when impurity levels were at normal plant solution concentrations. The ranges where the effect of the impurity became apparent were: greater than 20 ppb (parts per billion) for antimony; 40 ppb for germanium; 120 ppb for arsenic; and 7 …

Method And Apparatus For Making Aligned Flake Composite Wood Material Including Integral Baffles, Gordan P. Krueger, Anders E. Lund, Roy D. Adams

Michigan Tech Patents

A method and apparatus for forming a loosely felted mat of elongated wood flakes mixed with a binder, the mat including a longitudinal axis and the wood flakes being aligned in mutually parallel relation and parallel to the longitudinal axis of the mat. The wood flakes are held in alignment in the mat by a plurality of closely spaced thin planar baffles, the baffles being comprised of a material which can form an integral part of the mat.

Effect Of Refrigerant Charge And Condenser Temperature On The Operating Characteristics Of A Vapor-Compression Air Conditioning System, Ezzat Fikri Assaad

Archived Theses and Dissertations

No abstract provided.

Molded Wood Particle Pallet Having Increased Bending Strength, Bruce A. Haataja

Michigan Tech Patents

The invention includes a molded unitarily formed pallet comprising wood particles bonded together by a cured binder in compressed relation and forming a deck having an upper surface supporting a load, and a plurality of elongated substantially parallel spaced channels supporting the deck. The channels extend from adjacent one edge of the pallet to adjacent an opposite edge. The channels each including spaced channel side walls extending downwardly from said deck and terminating in a planar bottom wall parallel to the deck. The side walls are integrally joined at their upper edges to the deck and integrally joined at their …

Screening Design Test For Cobalt Cementation From Zinc Electrolyte, Mark S. Blaser, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

25th Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Abstracts and meeting program from the 25th annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 14-17, 1983.

Control Of Oxygen And Carbon Related Crystal Defects In Silicon Processing, P. D. Ownby, P. E. Grayson

Materials Science and Engineering Faculty Research & Creative Works

In the production of silicon articles at an elevated temperature, a stream comprising a controlled mixture of an oxygen-containing first gas and a second gas is admitted to the processing chamber. The first gas is one which partially dissociates under the conditions in the chamber to form both oxygen and the second gas. The second gas is one which is not harmful to silicon at the conditions in the chamber. Substantially equilibrium conditions are established in the chamber so that the dissociation of the first gas to oxygen occurs reversibly. The partial pressure of oxygen (P_O2) is sensed …

The Use Of Complex Versus Normal Modes In Structural Model Improvement, Chih Lin

Mechanical & Aerospace Engineering Theses & Dissertations

In the past, normal modes approximation to complex modes was employed by most researchers or users in the process of identification or modification of structural systems. This is true, of course for simple structures with no or proportional damping. For complex structures with nonproportional damping, even level of which is small, it will be shown that applying this approximation is inadequate. Use of complex modes instead of approximated normal modes is justified.

An algorithm is presented that computes a set of normal modes from the corresponding measured complex modes. The computed normal modes are then used in the Berman's technique …

Fuel And Process Efficiency's Affect On The Selection Of Surface Heat-Treating Processes, Christopher Scott Thorman

Graduate Research Papers

Ever since the advent of the Industrial Revolution part components and tooling have required production heat-treating to maximize life. Various forms of heat-treatment are available to heat-treating technologists and engineers, all of which have their advantages. To maximize investment, managers must decide between new processes to gain efficiency and the updating of current process to improve efficiency. Cost considerations are important but not the only ones. Quality and safety are also important to remember.

Production capacity, both present and future, is also related to cost effectiveness of heat-treating process. The heat-up and cool-down aspect which is a vital characteristic to …

Molded Wood Particle Products Including Integrally Joined Intersecting Members, Bruce A. Haataja

Michigan Tech Patents

A molded product formed from wood flakes intermixed with a binder and a first elongated member formed from elongated wood flakes compressed and bonded together with a binder, the wood flakes having a grain direction extending generally parallel to the longitudinal axis of the flakes and the flakes being generally oriented in alignment with the longitudinal axis of the first elongated member. A second elongated member intersects the first elongated member and is integrally joined to it. The second elongated member is also formed from elongated wood flakes compressed and bonded together with a binder, the wood flakes being generally …

The Effect Of Selected Alloying Elements On The Hardness And Microstructure Of Ductile Cast Iron, Chi-Hua Edward Tseng

Masters Theses

The effects of cooling rate and alloying element on the matrix structure, nodule count and hardness have been studied in this investigation.

Recommendations for producing ferritic ductile iron have been made and the relationship between hardness and pearlite percentage has been obtained in this study.

Development Of Glass Microspheres For Radiotherapeutic Applications, Thomas A. Wetteroth

Masters Theses

"Oxide glasses make excellent candidates for radiotherapeutic microspheres used in liver cancer treatment because of their generally high chemical durability and safety of manufacture. From the compositions containing ~5 wt% P₂O₅ studied, magnesium alumino silicate glass microspheres and magnesium alkali silicate glass microspheres with 4 wt% ZrO₂ had acceptably low releases of both elemental phosphorus in deionized water at 50°C, and radioactive ³²P in human blood plasma at 37°C. The relative ranking of glass compositions in the elemental phosphorus leach test shows good agreement with the rankings of compositions in the radioactive ³²P leach …

Separation Of Mineral Particles In Cyclones Under The Influence Of A Magnetic Field, Kwasi Amoako-Gyampah

Masters Theses

"The separation of mineral particles in a cyclone under the influence of a magnetic field was investigated using an electromagnetic - cyclone arrangement. Feed pulps of dolomite and magnetite were used in the study. Two different cyclone types were investigated: An air-type cyclone arrangement and a conventional cyclone arrangement. Magnetic field strengths of 0 to 3000 gauss (0 - 0.3 Tesla) were used in the study by varying the current through the coils of the electromagnet .

The parameters evaluated in the study were the grades and recoveries of the magnetic concentrates produced, the enrichment ratios, the improvement in recoveries …

Glass Formation And Properties In The Gallia-Calcia System, Glenn Whichard

Masters Theses

“The critical cooling rate for glass formation for melts containing from 37.5 to 68.0 mol % Ga₂O₃ varied from 310 ± 80°C/s to 855 ± 115°C/s. The crystallization temperature, microhardness, UV and visible transmission were measured. The density increased from 4.075 g/cm³ at 37.5 3 mol % Ga₂O₃ to 4.402 g/cm³ at 56.0 mol % Ga₂O₃. The refractive index, n_D, increased from 1.778 at 37.5 mol % Ga₂O₃ to 1.802 at 62.0 mol % Ga₂O₃. The IR spectra indicate …

Defect Chemistry Of La-Doped Strontium Titanate, Brian Keith Flandermeyer

Masters Theses

"Thermogravimetric measurements as a function of oxygen activity were performed in the temperature range of 1200°C to 1400°C on a series of La-doped SrTiO₃ compounds. A model postulating the crystallographic accommodation of ionic defects induced by the donor under oxidizing conditions is assumed. Thermodynamic calculations were performed to compare this model to the experimental results with reasonable success"--Abstract, page iii.

Mechanical Properties Of Alumina For Orthopedic Implant Use, Ho Tong Fang

Masters Theses

"The static fatigue, flexural strength and chemical corrosion of three commercially prepared, polycrystalline aluminas, two of orthopedic implant grade, were measured in demineralized water at 37°C and 70°C. The dissolution of a Ca-rich impurity phase, probably a glass, segregated at the grain boundaries and external surface, appears at least partially responsible for the significant difference in static fatigue of these three aluminas. The present results indicate that the minimum static fatigue in demineralized water, and the highest flexural strength in demineralized water and HF solution are both achieved by the alumina characterized by a low concentration of Ca at the …

Sintering Of Lif-Fluxed Srtio₃, Marie-Christine P. Proudian

Masters Theses

"Lithium fluoride (LiF) is used to enhance the sinterability of perovskites, as it results in the formation of a liquid phase. In this study, the mechanism and kinetics of sintering for LiF-fluxed strontium titanate (SrTiO₃) were investigated. The Sr/Ti ratio was varied between 0.98 and 1.03, and the LiF content in the green compact ranged from 0.5 to 2.0 weight percent. Sintering was conducted at temperatures between 695° and 925°C for isothermal dilatometric shrinkage measurements for time intervals of 6000 seconds or less. Weight loss, shrinkage, density and porosity measurements were conducted on samples isothermally sintered between 690° …

Preface, Delbert E. Day, Günther H. Frischat

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Comments On A Paper By Baik And Raj, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Twinning Pseudoelasticity In Intl, Manfred Wuttig, Lin Chun-Hung

Materials Science and Engineering Faculty Research & Creative Works

Twin boundaries generally contribute significantly to the damping of a twinned crystal. In an In-19.1 at.% Tl single crystal the damping gives rise to auto modulation if the internal friction studies are performed in the 10 Hz frequency range, with a strain amplitude larger than 0.05 and at temperatures lower than 10°C. The frequency of the auto modulation is about 60 times slower than the frequency with which the reed type sample is driven. The auto modulation frequency has a maximum at -6 C and is characterized by an activation energy of 29 kJ/mol (7 kcal/mol). This maximum can be …

The Influence Of Additives And Their Interactions On Copper Electrorefining, Chwan-Tsann Wang

Doctoral Dissertations

"Protein colloid (glue), thiourea, Avitone and chloride ion are the most common additives used electrorefining copper. The polarization behavior of these additives, single and combined, was studied by cyclic voltammetry techniques in conjunction with stationary and rotating disc electrodes. In the stationary electrode work, different protein colloids give substantially different results in polarization or interaction with other additives. The role played by Avitone is not clear, but it does somewhat modify other additives in the electrolyte. Thiourea can cause a depolarized peak and a polarized plateau depending on the concentration, the other additives present and the potential selected. Chloride ion …

Production Of Anhydrous 1,4-Dioxane, Jean Yamanis

Chemical and Materials Engineering Faculty Patents

This invention relates to the production of anhydrous 1,4-dioxane by the dimerization of ethylene oxide in the presence of an acidic type of cation exchanger, preferably an acidic cation exchanger resin having sulfonic acid groups associated therewith. The 1,4-dioxane is formed by contacting ethylene oxide in the liquid phase with an acidic-type cation exchanger at a first temperature and for a time sufficient to yield a reaction product of the ethylene oxide and the cation exchanger, and thereafter heating the reaction product at a second temperature higher than the first temperature and for a time period sufficient to dissociate the …

Speciation Of Cr (Iii) And Cr (Vi) Via Reversed Phase Hplc With Inductively Coupled Plasma Emission Spectroscopic Detection (Hplc-Icp)24, Richard N. Savage, I. S. Krull, D. Bushee, R. G. Schleicher, S. B. Smith, Jr.

Materials Engineering

Chromium ions, viz., chromic (Cr⁺³ = III) and chromate (Cr⁺⁶ = VI), can be reliably, conveniently, reproducibly, and quickly separated and detected by the use of conventional paired-ion, reversed phase (RP) high performance liquid chromatography (HPLC) together with refractive index (RI) and/or inductively coupled plasma emission spectroscopic (ICP) detection. A number of novel paired-ion approaches have now been developed, using PIC A (tetrabutylammonium hydroxide) or PIC B (sodium n-alkyl sulfonate) separately in the mobile phase. This allows for the retention of each Cr species depending on the particular ion pairing reagent being used, while the remaining Cr ion …

Nonlinear Anelasticity Of Magnesium, Alexander Aning, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

An approximate solution of the equation of motion of a nonlinear anelastic reed at or near resonance is presented. The steady state solution reproduces the well-known nonlinear resonances. The solution also predicts the existence of auto modulations, i.e., self-excited modulations of the amplitude and phase at constant power of excitation of the reed. Numerical examples of such auto modulations are presented for an antisymmetric deformation potential. Experimental studies of finite amplitude oscillations of a magnesium reed vibrating at 72 and 431 Hz at room temperature confirm the existence of auto modulations. The experimental results can be semi quantitatively described in …

Structural Members Comprised Of Composite Wood Material And Having Zones Of Diverse Density, Anders E. Lund, Gordan P. Krueger

Michigan Tech Patents

The disclosed invention includes an improved construction of structural members such as railroad crossties, highway spin posts and highway guard posts and to construction of said members from composite wood material including elongated wood flakes and to a method for making such improved structures.

24th Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Abstracts and meeting program from the 24th annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 1-5, 1982.