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Showing papers by "Michigan Technological University published in 1974"


Journal ArticleDOI
TL;DR: The most abundant and most frequently found minerals are: sulfur, hematite, halite, sylvite, gypsum, ralstonite, anhydrite, thenardite and langbeinite.

167 citations


Journal ArticleDOI
TL;DR: In this article, a review is presented of experimental observations reported on the structure of interphase boundaries since 1968, showing that nearly all observed boundaries are of the partially or fully coherent type, and hence the principal structural features examined were misfit dislocations and ledges.
Abstract: SUMMARY A review is presented of experimental observations reported on the structure of interphase boundaries since 1968. Nearly all observed boundaries are of the partially or fully coherent type, and hence the principal structural features examined were misfit dislocations and ledges. Observations were drawn from studies of precipitation, spinodal decomposition, oriented overgrowths and eutectics. Interphase boundary structures were found to be little affected in the main by the type of reaction through which they were developed and were consistent with Van der Merwe theory and a theory of precipitate morphology. Observations of these structures have been considerably facilitated by the efforts of Weatherly and co-workers to define the visibility and the optimum TEM viewing conditions of misfit dislocations and ledges. Important new observations on misfit dislocations made since 1968 include: misfit dislocation spacing in the Cr(Mo)/NiAl eutectic in good agreement with theoretical expectation because misfit dislocations are also glide dislocations and the interface plane is also the glide plane; misfit dislocations on θ′ Al-Cu and η Al-Au plates with a Burgers vector (a/2 ) stable only at an interphase boundary; reduction of the interfacial energy of partially coherent boundaries on the same precipitates by dislocation interactions and rearrangements; reduction of interfacial energy of interfaces developed during spinodal decomposition through rotation of the interface itself from {100} to {110}; and misfit dislocation boundaries between f.c.c. (Cu-rich) and b.c.c. (Cr) crystals made possible with the assistance of ‘structural ledges’. Growth ledges have now been observed in a number of alloy systems which have undergone precipitation from solid solution or eutectic solidification; they appear to be confirmed as a customary feature of migrating partially or fully coherent interphase boundaries. Much new experimental information has been obtained on the sources (exceedingly diverse), heights (usually appreciably higher than monatomic), spacings (irregular) and migration kinetics (diffusion-controlled if their edges are disordered) of ledges. New observations continue to confirm the complexity of the processes through which misfit dislocations are acquired. The Ashby-Johnson and the Brown-Woolhouse theories of misfit dislocation nucleation or acquisition by spherical precipitates are in encouraging agreement with experiment.

108 citations




Journal ArticleDOI
TL;DR: In this article, an Auger electron spectroscopy was employed to directly determine the cause of thermal embrittlement of 250 series maraging steel, and a drop in CVN energy with introduction of an embrittling intermediate anneal was directly correlated with a build-up of both Ti and C on the prior austenite grain boundaries.
Abstract: Auger electron spectroscopy was employed to directly determine the cause of thermal embrittlement of 250 series maraging steel. A drop in CVN energy with introduction of an embrittling intermediate anneal was directly correlated with a build-up of both Ti and C on the prior austenite grain boundaries. By following grain boundary concentration of Ti as a function of time at a given temperature, the diffusion coefficient for Ti in the maraging steel at 1600°F was determined. Finally, the further drastic drop in CVN energy on aging an embrittled specimen was shown to be due to a segregation of B to the already embrittled prior austenite grain boundaries, causing a further loss of cohesion.

44 citations



Journal ArticleDOI
TL;DR: In this paper, the problem of filtering artifact from QRST complexes of ECG records has been approached by the use of a digital, time-varying filter, and the optimum form of this filter assuming uncorrelated, zero-mean, additive noise is presented and shown to be equivalent to estimating the coefficients of an intrinsic component expansion of the complex.
Abstract: The problem of filtering artifact from QRST complexes of ECG records has been approached by the use of a digital, time-varying filter The optimum form of this filter assuming uncorrelated, zero-mean, additive noise is presented and shown to be equivalent to estimating the coefficients of an intrinsic component expansion of the complex Results are reported showing that QRST complexes in limb leads of normals may be accurately represented by only eight terms of the intrinsic component expansion A suboptimum filter is presented and results reported which show that an order of magnitude reduction of the 005 to 100 Hz artifact energy in the filtered complex can be achieved

33 citations




Journal ArticleDOI
TL;DR: In this paper, an Auger electron spectroscopy was used to characterize grain-boundary chemistry in MgO, Al2O3, and MgAl2O4 (spinel) hot-pressed with LiF or NaF.
Abstract: Auger electron spectroscopy was used to characterize grain-boundary chemistry in MgO, Al2O3, and MgAl2O4 (spinel) hot-pressed with LiF or NaF. The presence of additives (F, Na) at the grain boundaries was confirmed; observation of grain-boundary impurities in MgO extends previous studies.

27 citations




Journal ArticleDOI
TL;DR: 1. Kausch, W. : U m s c h a u 68, 373 (1968)
Abstract: 1. Kausch , W. : U m s c h a u 68, 373 (1968) 2. Bi~sgen, M.: Bau und Leben unse re r W a l d b a u m e , S. 61. J e n a : G. F i scher 19t7 3. Weber , P. : S.-B. Akad. Wiss. Wien, Abt . I, He f t 3/4, t25 (1916) 4. Klebs, G.: Abh. Heidelberger Akad. ~qss . , M a th . -na tu r wiss. K1.3, I ( t9t4) 5. Troll, M.: P rak t i s che E in f i ih rung in die P f l anzenmorphologie, Tell I, S. 141. J e n a : G. F i scher 1954


Journal ArticleDOI
TL;DR: In this article, a C-nucleoside analog of cordycepin, 6-amino-8-(3-deoxy-β-D-erythro-pentofuranosyl)purine (6), has been synthesized.

Patent
01 May 1974
TL;DR: In this article, the degradation of developed or undeveloped photographic film in a manner which permits also the recovery of silver and organic components from the film material in which the film is subjected to wet oxidation at high temperature and high pressure in the presence of a wet oxidation catalyst and a silver complexing compound.
Abstract: The destruction of developed or undeveloped photographic film in a manner which permits also the recovery of silver and organic components from the film material in which the film is subjected to wet oxidation at high temperature and high pressure in the presence of a wet oxidation catalyst and a silver complexing compound, and then subjecting the liquor from the wet oxidation step to processing to separate the solubilized silver which is freed from the film and to separate components derived from the film material in the liquor that remains.


Journal ArticleDOI
TL;DR: Aus dem Bis-hydrazon (I) erhalt man durch Reduktion das Diaminolacton (II), das with α-Oxo-aldehyden (III) zu den Pyrazinen (IV) and mit den Aldehyden(V) zusatzolinen (VI) kondensiert wird.


Journal ArticleDOI
TL;DR: In this paper, the eutectic between the aluminum solid solution and a compound Ag2Al has been determined for conditions of high temperature gradient and relatively low growth rates and it has been shown how composition and volume proportions the phases change with freezing rate in a given alloy.

Journal ArticleDOI
TL;DR: Gravity-model studies, combined with geologic studies, indicate that near Humboldt, Michigan, the Marquette Trough is ∼2,438 m deep and asymetrically shaped, the deepest section being near the southern edge.
Abstract: The presence of elongate troughs of Precambrian X (middle Precambrian) rocks in Precambrian W (lower Precambrian) rocks in the western Marquette district of northern Michigan has been known since the late 1800s. However, little data can be brought to bear on estimates of the depth and cross-sectional configuration of these features. For this reason, gravity models and geologic interpretations were made from gravity profiles measured over the Marquette Trough, Republic Trough, and Mitchigan River Trough. Gravity-model studies, combined with geologic studies, indicate that near Humboldt, Michigan, the Marquette Trough is ∼2,438 m deep and asymetrically shaped, the deepest section being near the southern edge; near the west end of Lake Michigamme, the Marquette Trough is about 1,097 m deep at its northern edge; the Republic Trough is about 1,524 m deep at a point ∼2.4 km northwest of its southeastern end; and the Mitchigan River Trough is probably a fault-bounded westward-dipping monocline ∼610 m deep.

Journal ArticleDOI
TL;DR: In this paper, an analytical technique is presented to combine viscously damped multi-dimensinal continuous systems with discrete springs or viscous dampers, and the known characteristics of the unconnected systems are used to generate a characteristic equation leading to the complete solution of the combined system.

Journal ArticleDOI
TL;DR: In this paper, a phenomenological analysis of the solid-solution hardening of ternary alloys in terms of the binary alloy hardening increments is presented for the case in which the solute atoms have different strengths as obstacles to dislocation motion.
Abstract: Measurements of the yield stress as a function of the solute content are reported for a series of ultra-high vacuum degassed Nb-Hf-W single crystals tested at 900°K. Tests of alloys containing up to 10 a/o (Hf + W) show that the yield stress increases with solute content in a nearly linear manner and that the rate of hardening per solute addition is the highest for the most concentrated alloys. Although second-phase precipitates are not expected and are not observed by transmission electron microscopy techniques, the yield stress of the concentrated Nb-Hf-W alloys is sensitive to heat treatment. A phenomenological analysis of the solid-solution hardening of ternary alloys in terms of the binary alloy hardening increments is presented for the case in which the solute atoms have different strengths as obstacles to dislocation motion. The analysis predicts the observed strengthening at total solute concentrations of less than about 5 a/o, but the observed rate of hardening exceeds that predicted at ...

Journal ArticleDOI
TL;DR: In this paper, the 2,5-di-p -nitrobenzoylated 2,3-anhydro-α-α and β-D -lyxo-furanoside (3 and 12 ) were obtained for 12 hours at 60 60 lb.in.

Journal ArticleDOI
TL;DR: The data suggest amino acids are important sources of four carbon dicarboxylic acid intermediates for continued oxidation of fatty acids, maintenance of blood glucose and replenishment of tissue glycogen stores during the latter stages of arousal.

Journal ArticleDOI
TL;DR: In this article, the following hexamethylphosphoramide (HMPA) solvates were prepared and characterized by elemental analysis, melting point, and i.r. spectra: LiCl.

Journal ArticleDOI
TL;DR: In this paper, a plan devised using dimensional analysis and assuming that bulk motion is the predominant mass transport mechanism in the system is presented, which is not true and serious errors may occur if scale-up calculations are based on assuming that the bulk motion predominates.
Abstract: System response data for step changes in input tracer concentration have been obtained for two different impeller agitated continuous flow mixing systems containing aqueous polysaccharide solutions. The vessel volumes were 1.6 and 10.9 liters. Polysaccharide concentration, dilution rate, and impeller speed were varied according to a plan devised using dimensional analysis and assuming that bulk motion is the predominant mass transport mechanism in the system. The data show that this is not true and that serious errors may occur if scale-up calculations are based on assuming that bulk motion predominates. Under the operating conditions used, perfect mixing was not observed.


Proceedings ArticleDOI
06 May 1974
TL;DR: Changes can be made in computer science courses to accommodate the changes in mathematics prerequisites and will result in strengthening the undergraduate program and allowing more time for advanced computer science topics.
Abstract: Many professors of computer science and computer engineering are relatively unaware of the changes in the secondary mathematics curriculum in the last decade. The changes in mathematics have major implications for the design of computer science and computer engineering curricula in the colleges and universities. The thesis of this paper is that changes can be made in computer science courses to accommodate the changes in mathematics prerequisites and will result in strengthening the undergraduate program and allowing more time for advanced computer science topics.

Journal ArticleDOI
TL;DR: In this paper, high-resolution, electron-impact, mass-spectrometric measurements have been made on three types of pyrazoles, namely, 5-styryl pyrazole, 3-carboxylates and 1-3,5-trisubstituted pyrazola.