| Recent Biaxial Test Results of Laminated Composites and Analytical MCT Predictions |
18 NOV 2004 |
16 pages |
| Authors:
Jeffry S. Welsh; J. S. Mayes; ALFRED UNIV NY
|
 | As the use of advanced composite materials continues to expand into new technology areas, a troublesome issue arises involving the inability of mainstream designers to accurately predict the initiation and growth of the material damage under multiaxial stress states. This shortcoming was clearly illustrated in impressive fashion under the recent "World Wide Failure Exercise". The inability to predict the load response of composite materials in the region of their ultimate ... |
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| Production of Distorted 3-3 Hydrophone Composites from Reticulated Ceramics |
27 FEB 97 |
10 pages |
| Authors:
D. A. Norris; ALFRED UNIV NY
|
| The most significant progress during this period was the completion of our first full sized (4'x4') conformable 3-3 composite array and it's delivery to Fred Geil of Northrup Grumman for testing. The array manufacture was a joint effort between Hi-Tech and Alfred University (Matt Creedon and Walter Schulze) with the next five arrays to be produced entirely by Hi-Tech Ceramics. We are still dependent on Alfred University for their poling ... |
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| Development of Microwave Ferrites for High Performance Applications |
22 JAN 97 |
5 pages |
| Authors:
Vasantha R. Amarakoon; Vernon L. Burdick; Yong S. Cho; ALFRED UNIV NY
|
| LiZn ferrites were investigated to control the resultant microstructure or to obtain nanoscale powders at a low temperature. Two nonconventional chemical methods are introduced. The sol-gel coating procedure was used to uniformly distribute additives like SiO2 and Bi2O3. These oxides improved the densification of the LiZn ferrites at low temperatures via a liquid phase sintering. Nanocrystalline LiZn ferrites were obtained at a low temperature of 400 deg C via the ... |
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| Design and Construction of Smart Materials Based on Piezoresistive Sensors and Multilayer Actuators |
26 APR 96 |
6 pages |
| Authors:
Walter A. Schulze; William B. Carlson; ALFRED UNIV NY
|
| PTCR (positive temperature coefficient of resistance) barium titanate was the active material for a ceramic sensor which employed piezoresistivity to detect changes in applied stress. High purity, chemically prepared barium titanate was donor-doped at an optimum level of 0.30 at% lanthanum to provide semiconductivity. A transition metal counterdopant was added at a level of less than 0.10 at% in some cases, to enhance the PTCR effect. The donor dopant and ... |
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| Production of Distorted 3-3 Hydrophone Composites from Reticulated Ceramics |
28 APR 95 |
11 pages |
| Authors:
D. A. Norris; ALFRED UNIV NY
|
| Samples were processed by Hi-Tech Ceramics and then supplied to Alfred University for firing, electroding and testing. Previously supplied samples encompassed: four pore sizes (15,30,45 and 65 ppi), undistorted and 2:1 aspect ratio distorted foam, two densities (10 and 15%), face coated and non- face coated reticulate. The samples supplied during the current reporting period included the same four pore sizes but of an increased, 3:1 aspect ratio, degree of ... |
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| Microstructural Effects on Far-Infrared Reflection Spectra of Alumina Ceramics. |
1995 |
|
| Authors:
R. Kudesia; A. E. McHale; ALFRED UNIV NY
|
 | Here, we present the results of a systematic study on alumina specimens to determine the relative magnitude of the effects of porosity and grain size on the calculated dielectric functions. Alumina ceramics are conventionally used as calibration standards in dielectric characterization and have the additional advantage of being well studied for sintering. MgO doping has been found to be useful for control of grain size variation while promoting the development ... |
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| Effects of La2O3/ZnO Additives on Microstructure and Microwave Dielectric Properties of Zr(0.8)Sn(0.2)TiO4 Ceramics. |
1994 |
|
| Authors:
Rajiv Kudesia; Anna E. McHale; Robert L. Snyder; ALFRED UNIV NY
|
| Dielectric ceramics of Zr(0.8)Sn(0.2)TiO4 containing La2O3 and ZnO as sintering aids were prepared and investigated for microstructure and microwave dielectric properties. Low-level doping with La2O3 and ZnO (up to 0.30 wt%) is good for densification and dielectric properties. These additives do not affect the dielectric constant and the temperature coefficient. Dielectric losses increase significantly at additive levels higher than 0.15 wt%. The combined additives La2O3 and ZnO act as grain ... |
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| Compositional Effects on the Liquid-Phase Sintering of Praseodymium Oxide-Based Zinc Oxide Varistors |
93 |
|
| Authors:
Aldo B. Alles; Robert Puskas; Gregory Callahan; Vernon L. Burdick; ALFRED UNIV NY
|
| The influence of the formation of eutectic liquid phases during sintering of the ternary varistor system ZnO-Pr6O11-Co3O4 was studied. The temperature at which the samples were observed to be liquid-phase sintered was found to depend on the nominal batch composition. The appearance of the liquid phase had a significant effect on the final microstructure as well as on the electrical properties of the varistors. Small additions of ZrO2, purposely added ... |
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| Design and Fabrication of TiC/NiAl Functionally Gradient Materials for Joining Applications |
92 |
|
| Authors:
Rajiv Kudesia; Scott E. Niedzialek; Gregory C. Stangle; James W. McCauley; Richard M. Spriggs; ALFRED UNIV NY
|
| Joined ceramic/intermetallic materials were synthesized by the self- propagating high-temperature synthesis process. The materials joined were TiC and NiAl, while the joint layer was a functionally gradient material layer consisting of TiC/NiAl in a prespecified spatial composition gradient. Microstructural analysis showed that the composition gradient was retained following the fabrication process. In addition, design calculations were performed for joined ceramic/metal composites. The first portion of the calculations dealt with the ... |
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| Influence of Thermal History on the Crystallization Behavior and Hardness of a Glass-Ceramic |
91 |
|
| Authors:
Rainer Roesky; James R. Varner; ALFRED UNIV NY
|
| The glass system SiO2-Al2O3-Li2O-TiO2 was examined to determine the dependence of hardness of heat-treatment temperature. In addition to hardness measurements, X-ray diffraction (XRD) was used to determine the type and amount of phases present and to relate this to the hardness results. Hardness increased with heat-treatment temperature. This correlated with the amounts of crystals present, as determined by XRD. For a particular heat-temperature, when hardness was plotted versus load on ... |
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| Further Studies on Ceramic Superconductor Motors |
91 |
|
| Authors:
X. W. Wang; J. Koprevich; R. C. Ward III; N. R. Mannur; H. Petersen; ALFRED UNIV NY
|
| Several small stepper motors have been developed. Each motor consists of a superconductive primary and a magnetic secondary. The primary is comprised of a mixture of Y1Ba2Cu3O(7-x) superconductive powder and an epoxy resin. The construction of a rotational motor is presented. The evaluation of a linear motor is also given. |
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| Insights Provided by Fractography in Strength Testing of Machined Si3N4 and Indented Al2O3 |
91 |
|
| Authors:
Emilio S. Alfaro; James V. Guiheen; James R. Varner; ALFRED UNIV NY
|
| The importance of fractography in interpreting strength results was demonstrated in two studies. In the one, machined specimens of hot-pressed Si3N4 were broken after the surface stresses had been determined using the sin sq psi technique of X-ray diffraction. Fractography showed that machining flaws were responsible for determining strengths when coarser diamond grits were used, but that the residual stresses (compressive at the surface) and processing flaws were increasingly important ... |
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| Raman Microprobe Investigation of Oxygen and Carbon Dioxide Dissolution from Bubbles in Silicate Glasses Containing Arsenic Oxide |
90 |
|
| Authors:
S. W. Lee; Sr. Condrate R. A.; ALFRED UNIV NY
|
| Raman microprobe analysis was used to investigate the changes in the relative concentrations of oxygen and carbon dioxide found in bubbles in silicate glasses containing different amounts of arsenic oxide, sodium nitrate, and/or sodium nitrite after heat treatments. As expected, analysis of the spectral data clearly indicated that addition of arsenic oxide to the glass accelerates the relative rate of oxygen dissolution with respect to carbon dioxide. Addition of either ... |
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| Influences of Zirconia and Silicon Nucleating Agents on the Devitrification of Li2O.Al2O3.6SiO2 Glasses |
90 |
|
| Authors:
J. Y. Hsu; R. F. Speyer; ALFRED UNIV NY
|
| The effects of Si and ZrO2 dopants on the crystallization and phase transformation process in Li2O.Al2O3.6SiO2 glasses were investigated using differential thermal analysis, X-ray powder diffractometry (XRD), and high- resolution transmission electron microscopy (TEM) interactively. Phase separation was observed in the studied glasses prior to substantial crystallization. Elemental Si (1 mol%) significantly aided in glass devitrification. Droplet-like phase-separated regions in the as-quenched or heat-treated glass devitrified at 760C, which in ... |
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| Some Observations on the Role of Dopants in Phase Transitions in Zirconia from Atomistic Simulations |
90 |
|
| Authors:
Alastair N. Cormack; Stephen C. Parker; ALFRED UNIV NY
|
| Attempts to calculate the free energy of the polymorphs of zirconia are reported. The results suggest a theoretical basis for the phase transitions in terms of the removal of lattice instabilities (evidenced by imaginary phonon frequencies). Dopant stabilization of the higher symmetry structures is seen to arise because of changes to the phonon frequencies due to the different mass and effective charge of the dopant. |
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| Microstructural Evolution of Sol-Gel Mullite |
90 |
|
| Authors:
G. Klaussen; G. S. Fischman; J. L. Laughner; ALFRED UNIV NY
|
| This paper describes a study of reactions and microstructures during the transition of a precursor colloidal gel to mullite in the region of 1100- 1400 C. A simultaneous thermal analyzer is used to identify reaction temperatures. Microstructural evolution is studied by X-ray analysis. Results include the identification of intermediate phases produced during the sintering phenomenon. |
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| Flexural Strength of Pb and Al Doped BiCaSrCuO Superconductors |
90 |
|
| Authors:
X. W. Wang; M. Scott; J. Sanford; J. Varner; ALFRED UNIV NY
|
| We report new results on the Pb, and Al doped Bi-Ca-Sr-Cu-O superconductors. The flexural strength of pure Bi-Ca-Sr-Cu-O compound is close to that of pure Y-Ba-Cu-O compound via four point bend measurement. After Pb, and Al doping, the strength is dependent on the concentration of the dopant. The superconducting transition temperatures are also altered. Studies on X-ray diffraction and SEM will be presented. The relation between the flexural strength and ... |
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| Properties of Calcium, Strontium, and Barium Galliosilicate Glasses |
90 |
|
| Authors:
Laura A. Balewick; James E. Shelby; ALFRED UNIV NY
|
| Glasses in three alkaline-earth (Ca, Sr, and Ba) galliosilicate systems were prepared, and the density, viscosity, thermal expansion coefficient, and glass transformation temperature were measured. All glasses contain 30 mol% alkaline-earth oxide. It is suggested that alkaline-earth ions can play a role in the glass structure which is similar to that of an intermediate ion. |
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| Nitridation of Phosphate Glass Melts with Ammonia |
89 |
|
| Authors:
Martin Heuberger; L. D. Pye; ALFRED UNIV NY
|
| A sodium metaphosphate glass melt was nitrided with ammonia in a tilted tube furnace with a rotating crucible. An optimum nitridation temperature of 780 C led to 7.2 wt% of nitrogen in a clear glass in 10 hours. Crystallization of this glass was greatly reduced by incorporation of nitrogen. From these results a reaction mechanism and structural model is developed. This model provides a better understanding of the nitridation process ... |
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| Preparation and Evaluation of Silicon Nitride Matrices for Silicon Nitride-SiC Fiber Composites |
FEB 88 |
|
| Authors:
S. R. Axelson; ALFRED UNIV NY
|
| This research deals with the addition of continuous silicon carbide fiber to three types of silicon nitride matrices. Efforts were aimed at producing a dense silicon nitride matrix from reaction-bonded silicon nitride by hot-isostatic-pressing and pressureless sintering, and from silicon nitride powder by hot-pressing. The sintering additives utilized were chosen to allow for densification, while not causing severe degradation of the fiber. The ceramic microstructures were evaluated using scanning optical ... |
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| The Extinction Coefficient for CO2 Dissolved in a Heavy Metal Fluoride Glass |
88 |
|
| Authors:
J. M. Jewell; J. Coon; J. E. Shelby; ALFRED UNIV NY
|
| A heavy metal fluoride glass was heat treated for 4 hours at 750 C under both argon and CO2. Melts treated under CO2 show a narrow absorption band in the infrared spectra at 2350 /cm. Under argon, this absorption is greatly diminished for glasses treated. After the heat treatment procedure, the infrared spectra of each glass was measured. Following the infrared measurement, each sample was remelted under vacuum and outgassed ... |
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| Non-Stoichiometric Compounds |
87 |
|
| Authors:
Alastair N. Cormack; ALFRED UNIV NY
|
| The elements of the first transition series form oxides which display wide variety of defect related phenomena such as non-stoichiometry and diffusion. Many of these oxides have been studied extensively in recent years; partly because of their intrinsic interest and partly because they are important technologically in high temperature oxidation, catalysis etc.). In this paper the current appreciation of diffusion processes in some of these oxides is reviewed in terms ... |
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| Possible Uses of Manganese Dioxide in Ceramic Applications--Literature Review and Analysis |
11 FEB 80 |
|
| Authors:
D. R. Rossington; ALFRED UNIV NY
|
| This report presents a literature review of current uses of MnO(sub 2) and suggestions for future research. The historical background, oceanographic distribution, geology, exploitation, law, and politics of MnO(sub 2) are included. Uses of MnO(sub 2) in ferrites, semiconductors, catalytic processes, thermoluminescence, and photochromic materials are presented. A select bibliography of 33 items and 129 references are presented at the end of the report. |
|
| QUALITY ASSURANCE IN CERAMIC INDUSTRIES |
78 |
|
| Authors:
V. D. Frechette; L. D. Pye; D. E. Rose; ALFRED UNIV NY
|
| The rationale for integrated quality assurance programs is presented, along with tradition and new statistical methods. Other topics covered include raw materials production and procurement, product reliability, and the underlying economic philosophy. Additional chapters treat more specialized examples of quality assurance programs utilized in the manufacture of glass, whitewares, refractories, abrasives, electroceramics, structural clay products, and such specialized ceramics as those used in igniters and turbines, and nuclear ceramics. Lifetime ... |
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| FUEL CELL ELECTRODE PROCESSES. I. CATALYSIS AND CHEMISORPTION |
NOV 1959 |
|
| Authors:
GEORGE J. YOUNG; RALPH B. ROZELLE; ALFRED UNIV NY
|
|
| RESISTANCE HOT PRESSING |
AUG 1959 |
|
| Authors:
ALFRED UNIV NY
|
|
| METAL-CERAMIC LAMINATES |
NOV 1958 |
|
| Authors:
R.K. FRANCIS; R. Brown; ALFRED UNIV NY
|
|
| MEASUREMENTS OF THERMAL DIFFUSIVITY AND BIOT'S MODULUS FOR DENSE ALUMINA BETWEEN 1500 AND 1800 C BY AN UNSTEADY-STATE METHOD |
15 APR 1956 |
|
| Authors:
A.E. JR. PALADINO; E.L. SWARTS; ALFRED UNIV NY
|
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Reports by Corporate Author
