Michigan Technological University

About: Michigan Technological University is a education organization based out in Houghton, Michigan, United States. It is known for research contribution in the topics: Population & Volcano. The organization has 8023 authors who have published 17422 publications receiving 481780 citations. The organization is also known as: MTU & Michigan Tech.

New cubic phases formed by alloying Al3Ti with Mn and Cr

Abstract: It has been found that Mn or Cr can substitute for Al in Al 3 Ti and change the crystal structure from tetragonal DO 22 to cubic L1 2 . The new phases have been produced with negligible porosity and second phases, and have compositions near Al 67 Mn 8 Ti 25 and Al 67 Cr 8 Ti 25 . As with other cubic forms of Al 3 Ti, the ternary addition can range from bout 5 to 15 at. pct. while still maintaining the cubic phase. These new cubic phases have significantly reduced hardnesses and greatly improved crack resistance compared to binary Al 3 Ti, as well as other cubic forms based on alloying with Fe, Ni, or Cu. In addition to appreciable ductility in compression, the new phases show some tensile ductility

Extracellular Matrix Assembly in Diatoms (Bacillariophyceae) (I. A Model of Adhesives Based on Chemical Characterization and Localization of Polysaccharides from the Marine Diatom Achnanthes longipes and Other Diatoms)

Abstract: Extracellular adhesives from the diatoms Achnanthes longipes, Amphora coffeaeformis, Cymbella cistula, and Cymbella mexicana were characterized by monosaccharide and methylation analysis, lectin-fluorescein isothiocyanate localization, and cytochemical staining. Polysaccharide was the major component of adhesives formed during cell motility, synthesis of a basal pad, and/or production of a highly organized shaft. Hot water-insoluble/hot 0.5 M NaHCO3-soluble anionic polysaccharides from A. longipes and A. coffeaeformis adhesives were primarily composed of galactosyl (64-70%) and fucosyl (32-42%) residues. In A. longipes polymers, 2,3-, t-, 3-, and 4-linked/substituted galactosyl, t-, 3-, 4-, and 2-linked fucosyl, and t- and 2-linked glucuronic acid residues predominated. Adhesive polysaccharides from C. cistula were EDTA-soluble, sulfated, consisted of 83% galactosyl (4-, 4,6-, and 3,4-linked/substituted) and 13% xylosyl (t-, 4f/5p-, and 3p-linked/substituted) residues, and contained no uronosyl residues. Ulex europaeus agglutinin uniformly localized [alpha](1,2)-L-fucose units in C. cistula and Achnanthes adhesives formed during motility and in the pads of A. longipes. D-Galactose residues were localized throughout the shafts of C. cistula and capsules of A. coffeaeformis. D-Mannose and/or D-glucose, D-galactose, and [alpha](t)-L-fucose residues were uniformly localized in the outer layers of A. longipes shafts by Cancavalia ensiformis, Abrus precatorius, and Lotus tetragonolobus agglutinin, respectively. A model for diatom cell adhesive structure was developed from chemical characterization, localization, and microscopic observation of extracellular adhesive components formed during the diatom cell-attachment process.

Drought reduces root respiration in sugar maple forests

Abstract: Soil moisture deficits can reduce root respiration, but the effects have yet to be quantified at the stand level or included in models of forest carbon budgets. We studied fine-root (≤1.0 mm diameter) respiration in four sugar maple forests for three growing seasons in order to assess the combined effects of temperature, N concentration, and soil moisture on respiration rates. Fine-root respiration at the four sites was exponentially related to soil temperature and linearly related to root N concentration and soil moisture availability. Most of the variability in respiration rates was explained by temperature. Differences in soil moisture availability explained temporal variation within sites in respiration rate at a given temperature, whereas differences among sites in respiration rates resulted from site-specific differences in fine-root N concentration. Periodic moisture deficits during 1995 and 1996 were sufficient to cause declines of up to 17% in total growing-season root respiration at affected sit...

Student Understanding of Chemical Equation Balancing.

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.