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.

Porous nickel oxide nano-sheets for high performance pseudocapacitance materials

Abstract: We report a new nano-geometry based on porous nickel oxide nano-sheets for high performance pseudo-capacitance materials The porous nickel oxide nanosheets were fabricated by synthesizing porous Ni(OH)2 sheets by surfactant-templated wet chemistry followed by the decomposition of hydroxides to oxides upon thermal treatment The nickel oxide nanosheets display tunable specific capacitance varying from 641 to 1025 F/g at a charge–discharge current density of 3 A g−1, and from 326 to 445 F/g at 15 A/g By optimizing the thermal annealing conditions (eg, 300 °C for 3 h), the electrochemical performance can be achieved with a high capacitance of 993 F/g at current density of 3 A g−1, and 445 F/g at 15 A g−1 with an excellent cycle stability Detailed XRD, CV, EIS, UV and XPS characterization indicated that the interplay among the surface area, morphology, pore size distribution, crystal size and defect determined the electrochemical performance of porous NiO nanosheets as pseudocapacitive materials The unique nano-sheet geometry and intrinsically high surface area may have a great potential for designing high performance supercapacitors with simultaneous high power and energy densities, and the reported surfactant-templated wet chemistry approach may also be applicable for developing various metal oxide nano-sheet pseudo-capacitance materials for electrochemical energy storage

The influence of mass transfer characteristics and porous media heterogeneity on nonaqueous phase dissolution

Abstract: A two-dimensional multiphase flow and species transport model was developed and applied to the case of nonaqueous phase liquid (NAPL) emplacement and dissolution in both homogeneous and heterogeneous porous media systems. Simulations were performed to observe dissolution rate variations and the degree of NAPL-aqueous phase nonequilibrium as a function of two aqueous phase velocities and five forms of the NAPL-aqueous phase mass transfer formulation. An integrated form of the Damkohler number was introduced to analyze the degree of NAPL-aqueous phase nonequilibrium. Mass removal rates for homogeneous media were insensitive to the form of the NAPL-aqueous phase mass transfer formulation, yielding results similar to a local equilibrium approach for all but one mass transfer formulation. This latter formulation was most sensitive to NAPL saturation and yielded significant nonequilibrium behavior, which was manifested as a decrease in NAPL dissolution rates as the NAPL volume fraction decreased. Variations in mass elution rates between homogeneous and heterogeneous media were observed, with more significant variations found for variances in porous media properties than for horizontal correlation lengths. In heterogeneous media, decreases in dissolution rates were attributed to the existence of relatively immobile regions of NAPL with saturations greater than the residual saturation of the media, so-called NAPL pools. These results illustrate the importance of the statistical characteristics of heterogeneous porous media on NAPL distribution and dissolution processes.

The Technical Communicator as Author Meaning, Power, Authority

Abstract: The authors explore the parallels to be found by comparing descriptions of the technical communicator with differing views of the communication process—the transmission, translation, and articulation views of communication. In each of these views, the place of the technical communicator and of technical discourse shifts with respect to the production of meaning and relations of power. The authors argue from the standpoint of the articulation view for a new conception of the technical communicator as author and of technical communication as a discourse that produces an author.