Showing papers by "Michigan Technological University published in 1985"
TL;DR: The genus Klebsiella is seemingly ubiquitous in terms of its habitat associations, but phenotypic and genotypic studies have shown that "K. pneumoniae" actually consists of at least four species, all with distinct characteristics and habitats.
Abstract: The genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that “K. pneumoniae” actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae—humans, animals, sewage, and polluted waters and soils; K. oxytoca—frequent association with most habitats; K. terrigena— unpolluted surface waters and soils, drinking water, and vegetation; K. planticola—sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis—infrequently detected (primarily with humans).
231 citations
TL;DR: In this article, high school chemistry students from two different schools were interviewed in depth on how they balanced simple chemical equations, the knowledge they employed while balancing the equations, and their representation of the balanced equations with diagrams.
Abstract: Fourteen high school chemistry students from two different schools were interviewed in depth on how they balanced simple chemical equations, the knowledge they employed while balancing the equations, and their representation of the balanced equations with diagrams. The equations were of the type employed when students are first introduced to chemical equation balancing in high school. All students were able to successfully balance the four equations presented to them. However, seven of the twelve students were not able to construct diagrams that were reasonably consistent with the notation of the balanced equation. It was further noted that these same students possessed very poor understanding of the concept of chemical subscript and were willing to violate the balancing rule which states that subscripts are not to be changed while balancing equations. The five students who were able to make consistent diagrams also possessed good concepts of subscript and the balancing rule.
164 citations
TL;DR: In this paper, it was shown that in the absence of sodium, molecular attachment by the TPRE mechanism is incidental but in the presence of sodium this is the dominant growth mechanism.
162 citations
TL;DR: In this article, a model is developed to explain the strength of two-phase materials and the predictions of it are compared to results obtained in several systems and the agreement between the model developed and experimental results is good.
151 citations
TL;DR: In this article, a set of partial differential equations of the diffusion-reaction type for the evolution of dislocation species was derived by distinguishing among mobile and immobile dislocations and operating within the framework of continuum mechanics.
104 citations
TL;DR: In this article, a technique has been developed to predict the adsorption equilibria of known organic solutes onto granular activated carbon (GAC) in mixtures of unknown composition.
99 citations
TL;DR: In this article, a method for calculating the inception voltage and corona current in humid air was proposed, and it was found that the photoelectrons distribution within the ionization layer, which depends upon the gap geometry, plays an important role in deciding whether the inception voltages increases or decreases with relative humidity.
Abstract: A method is suggested for calculating the inception voltage and corona current in humid air. It is found that the photoelectrons distribution within the ionization layer, which depends upon the gap geometry, plays an important role in deciding whether the inception voltage increases or decreases with relative humidity. The inception voltage is one of the boundary conditions required in the theoretical analysis of the corona V-I characteristics also presented. The experimental results reported in the literature which differ widely can be explained in the light of the present findings.
86 citations
TL;DR: Halite particles about 2 micrometers in size were collected by a quartz crystal microbalance cascade impactor from the El Chich�n eruption cloud in the lower stratosphere during April and May 1982, and there is evidence that they reacted with sulfuric acid after about 1 month, releasing gaseous hydrogen chloride.
Abstract: Halite particles about 2 micrometers in size were collected by a quartz crystal microbalance cascade impactor from the El Chichon eruption cloud in the lower stratosphere during April and May 1982. These particles are probably derived from the erupted chloride-rich, alkalic magma. Enrichments of hydrogen chloride and increases in optical depolarization in the eruption cloud observed by lidar measurements may reflect the influence of the halite particles. There is evidence that the halite particles reacted with sulfuric acid after about 1 month, releasing gaseous hydrogen chloride, which can influence the catalytic destruction of ozone in the stratosphere.
84 citations
TL;DR: The ductility of ZIRCALOY *-2 sheets containing 21-615 wt ppm hydrogen has been investigated at room temperature over a range of stress states from uniaxial to equibiaxial tension as discussed by the authors.
Abstract: The ductility of ZIRCALOY *-2 sheets containing 21-615 wt ppm hydrogen has been investigated at room temperature over a range of stress states from uniaxial to equibiaxial tension. Data based on locally determined fracture strains show a decrease in ductility with both increasing hydrogen content and increasing degree of biaxiality of the stress state. Metallographic and fractographic examinations indicate that the embrittlement is a consequence of void nucleation (due to hydride fracture), void growth, and void link-up. The influence of hydrogen content and stress state on each of the sequential stages of ductile fracture is determined. These results indicate that the primary cause for the influence of stress state on the hydrogen embrittlement of the ZIRCALOY sheet is that void link-up is initiated at a much lower critical void density in equibiaxial tension than in uniaxial tension. This appears to be a result of equibiaxial deformation enhancing (a) direct participation of previously unfractured hydrides in providing a fracture path linking up voids and (b) a localized shear instability process which is triggered by the nucleation of voids.
71 citations
TL;DR: In this paper, the authors examined the possible influences of sex and family wage earning status on worker satisfaction with respect to their job satisfaction, and developed logic to suggest that these factors may influence worker satisfaction.
Abstract: Past examinations of the job-related sources of worker satisfaction, though numerous, have ignored the possible influences of sex and family wage earning status. Developing logic to suggest that wo...
60 citations
TL;DR: In this paper, several alloys of Ductile cast iron containing various amounts of manganese, molybdenum, and nickel were austempered in the temperature range 316° to 427 °C.
Abstract: Several Alloys of Ductile Cast Iron containing various amounts of manganese, molybdenum, and nickel were austempered in the temperature range 316° to 427 °C. The rate and morphology of ferrite platelet formation (bainite reaction) were studied by optical metallography, x-ray diffraction, and hardness measurements. Austenitizing temperature, austempering temperature, and deformation by rolling were used as variables to control the kinetics of ferrite formation, stage I of the austempering reaction.
TL;DR: In this article, the rate of emission of SO2 from Mt Erebus was determined to be 230±90 tonnes day−1 during an 11-day period in December 1983.
Abstract: Mount Erebus is the principal source of volcanic emanations to the atmosphere in Antarctica. The rate of emission of SO2 from Mt Erebus was determined to be 230±90 tonnes day−1 during an 11-day period in December 1983. This is a more accurate and much higher estimate than previous ones. Because of the very constant character of the volcano's activity from the earliest observations until September 1984, the emission rate is possibly representative of the past 20 yr. The new data are important for accurate assessment of volcanic input to the clean Antarctic atmosphere, and are a useful baseline for the changes in emission rates which will be measured now, after Erebus has begun a new energetic eruptive period.
TL;DR: The predominant 4-desmethylsterols from the leaves of 13 species in eight genera of the family Chenopodiaceae are 24α-ethylsterols, and the saturated side chain analogues predominate with more than 70% of the 24-ethylcholesta-7,24(28)Z-dien-3β-ol in eight species.
Abstract: The predominant 4-desmethylsterols from the leaves of 13 species in eight genera of the family Chenopodiaceae are 24α-ethylsterols. In four species,Chenopodium ambrosioides L.,C. rubrum L.,Salicornia europaea L. andS. bigelovii Torr., the C-22(23) double bond is introduced into more than 70% of the 24α-ethylsterols producing spinasterol (24α-ethylcholesta-7,22E-dien-3β-ol) in the first two species and mixtures of spinasterol and stigmasterol (24α-ethylcholesta-5,22E-dien-3β-ol) in the latter species. The saturated side chain analogues predominate with more than 70% of the 24α-ethylsterols in eight species.Salsola kali L.,Suaeda linearis (Ell.) Moq.,Kochia scoparia (L.) Roth., andBassia hirsute (L.) Aschers. synthesize sitosterol (24α-ethylcholest-5-en-3β-ol), andAtriplex arenaria Nutt.,C. album L.,C. urbicum L. andC. leptophyllum Nutt. possess mixtures of sitosterol and 22-dihydrospinasterol (24α-ethylcholest-7-en-3β-ol). Sitostanol (24α-ethyl-5α-cholestan-3β-ol) was isolated fromSuaeda linearis as an 18% component of the total 4-desmethylsterol and in lesser amounts from four other species. In all species synthesizing 24-ethyl-Δ5-sterols, a 24ξ-methylcholest-5-en-3β-ol was also present at 1.0–20% of the total 4-desmethylsterol. Avenasterol [24-ethylcholesta-7,24(28)Z-dien-3β-ol], isofucosterol [24-ethylcholesta-5,24(28)Z-dien-3β-ol), cholesterol (cholest-5-en-3β-ol) and 24ξ-methyl-5α-cholestan-3β-ol also were isolated from several species. Species in the family Chenopodiaceae and the type genusChenopodium may be categorized into one of three groups based on sterol biosynthesis: the Δ7-sterol producers; the Δ5-sterol producers, and those producing mixtures of both Δ7- and Δ5-sterols in relatively fixed percentage compositions.
TL;DR: In this article, the toxicities of the starting compounds and the residual toxicity of the end-product solutions were measured with 48-h acute toxicity tests using Daphnia magna.
TL;DR: All-electron, density-functional calculations on an hcp Be dilayer find c/a at equilibrium to be 1.69 +- 0.03, a = 4.20 +-0.02 a.u. (Kohn, Sham, Gaspar); in either case there is very weak interplanar bonding.
Abstract: All-electron, density-functional calculations on an hcp Be dilayer find c/a at equilibrium to be 1.69 +- 0.03, a = 4.20 +- 0.02 a.u. (Kohn, Sham, Gaspar) or c/a = 1.69 +- 0.02, a = 4.10 +- 0.03 a.u. (Hedin and Lundqvist). In either case there is very weak interplanar bonding. While these structural properties are noticeably different from those of the bulk crystal, the dilayer work function (Hedin and Lundqvist) is essentially identical to the experimental bulk value.
TL;DR: In this article, Boyes and Ponter reported an increase in contact angle with decreasing drop size at the boiling point in pure vapor atmosphere, confirming the results of Good and Koo.
Abstract: Advancing contact angles are reported for the water-PTFE, water-copper, water-stainless steel, water-PMMA andn-decane-PTFE systems for a range of liquid drop sizes. The angles were determined at 25 °C in an air or nitrogen-saturated atmosphere and compared with those measured at the boiling point in an environment only of its vapor. For water-PTFE and water-PMMA systems, a decrease in contact angle with decreasing drop size was observed in an air-saturated environment at 25 ° confirming the data of Good and Koo. An increase in contact angle however occurred with decreasing drop size at the boiling point in the pure vapor atmosphere confirming the results of Boyes and Ponter. The introduction of nitrogen decreased the contact angle although the trend remained the same.
Patent•
09 May 1985TL;DR: The froth flotation device as mentioned in this paper includes a flotation column partially filled with a packing which defines a large number of small flow passages extending in a circuitous pattern between the upper and lower portions of the column.
Abstract: The froth flotation device includes a flotation column partially filled with a packing which defines a large number of small flow passages extending in a circuitous pattern between the upper and lower portions of the column. A conditioned aqueous pulp of a mineral ore, such as iron ore, is introduced into the midzone of the column. A pressurized inert gas, such as air, is introduced into the bottom of the column and is forced upwardly through the flow passages in the packing. As the air flows upwardly through these flow passages, it is broken into fine bubbles which intimately contact the floatable particles (e.g., iron oxide) in the aqueous pulp and forms a froth concentrate or float fraction which overflows from the top of the column. Wash water is introduced into the top of the column and flows through the flow passages in the packing countercurrently to the float fraction to scrub entrained non-floatable particles (e.g., gangue) from the froth concentrate. A tailing fraction containing the non-floatable particles is withdrawn from the bottom of the column.
TL;DR: In this article, a gas leakage model has been developed to simulate explosive gas leakage around fragments after casing breakup, and the model predicts definitive final fragment velocities in excellent agreement with the experimental data.
TL;DR: In this paper, the authors test the hypothesis that cyclical metal mining activity is more stable when multi-metal products are produced and develop a theoretical short run supply curve for a metal showing byproduct, co-product, and main product behaviour.
TL;DR: The Ayarza calderas, southeastern Guatemala, formed upon an eruption of a mixed plinian air fall that is locally overlain by a comagmatic ash-flow deposit as mentioned in this paper.
TL;DR: The application of the Data Dependent Systems (DDS) methodology is proposed for the modal identification and characterization of dynamic properties of a data dependency system and its validity is established by means of a simulation study.
Abstract: The application of the Data Dependent Systems (DDS) methodology is proposed for the modal identification and characterization. Difference equation models derived from sampled free and forced response information are shown to quantitatively define the dynamic properties of the system. A modal decomposition of the DDS models, based on modern linear system theory in the state space format and analysed from the standpoint of theoretical modal analysis, yields the system eigenvalues and eigenvectors, and the parameters of a lumped structural model. The theoretical background is presented in detail; its validity is established by means of a simulation study. Advantages of the DDS approach are discussed. Although the simulation study, and to some extent the terminology, are based on mechanical systems, the method has applications in wider fields, e.g., electromagnetic radiation and scattering.
TL;DR: In the most weakly foliated rocks, cleavage is defined by the preferred orientation of individual mica particles as mentioned in this paper, which is represented by short discontinuous mica film segments, thought to have formed by the recrystallization of early pore-space layer silicates.
TL;DR: The variation of contact angle of liquid sessile drops on solids has been attributed to roughness (Wenzel2), the static charge effect (Holly,3 Ponter and Yekta-Fard3) and contamination at the solid surface or in the liquid and gaseous phases as mentioned in this paper.
Abstract: The variation of contact angle of liquid sessile drops on solids has been attributed to roughness (Wenzel2), the static charge effect (Holly,3 Ponter and Yekta-Fard3) and contamination at the solid surface or in the liquid and gaseous phases.
TL;DR: The user interface, which includes off-line and on-line methods, is the link between the designer's conceptual model of the system's functions, capabilities and limitations and the user's cognitive model.
Abstract: People are continually creating and accessing internal representations of their current situation. I refer to this as their cognitive model. During an interaction with a computer system the person will form a cognitive model of the interaction that contains what he believes are the functions, capabilities and limitations of the system. An invalid or missing cognitive model will lead to user dis-satisfaction, a lack of confidence in the system and, hence, inefficient use of the system and human resources. The user interface, which includes off-line and on-line methods, is the link between the designer's conceptual model of the system's functions, capabilities and limitations and the user's cognitive model. The interface must present the system to the user in such a manner as to guide the user's cognitive model development to where it coincides with the designer's conceptual model. Awareness of the user's developing cognitive model will enable the production of a more effective human-computer interface.
TL;DR: In this paper, the inviscid limit of the α-effect in a sphere is approached both by direct numerical solution and by solution of a simpler nonlinear eigenvalue problem deriving from asymptotic boundary layer analysis for the case of stress-free boundaries.
Abstract: Two distributions of the α-effect in a sphere are considered. The inviscid limit is approached both by direct numerical solution and by solution of a simpler nonlinear eigenvalue problem deriving from asymptotic boundary layer analysis for the case of stress-free boundaries. The inviscid limit in both cases is dominated by the need to satisfy the Taylor constraint which states that the integral of the Lorentz force over cylindrical (geostrophic) contours in a homogeneous fluid must tend to zero. For a small supercritical range in α, this condition can only be met by magnetic fields which vanish as the viscosity goes to zero. In this range, the agreement of the two approaches is excellent. In a portion of this range, the method of finite amplitude perturbation expansion is useful, and serves as a guide for understanding the numerical results. For larger α, evidence from the nonlinear eigenvalue problem suggests both that the Taylor state exists, and that the transition from small to large amplitud...
TL;DR: In this article, the feasibility of characterizing the structural properties of snow from its acoustic behavior is demonstrated by means of acoustic sounding, where acoustic pulses incident perpendicularly on the snow surface and their return echos can be analyzed by the cepstral technique.
TL;DR: In this article, the influence of grain size on the hydrogen embrittlement of titanium sheets is shown to depend on stress state, and it is shown that the deleterious effect of a large grain size and large gain/hydride sizes on the susceptibility of titanium sheet is more severe in equibia xial tension than in uniaxial tension.
TL;DR: In this paper, the authors developed an appropriate mathematical model to study the behavior of the stress waves in the radial-tangential plane of utility poles, which could increase the ability to use the sonic testing method in field testing procedures.
Abstract: The objective of this study was to develop an appropriate mathematical model to study the behavior of the stress waves in the radial-tangential plane of utility poles. It is hoped that such a study could increase the ability to use the sonic testing method in field testing procedures.