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.

Single-Walled Carbon Nanotube/Poly(methyl methacrylate) Composites for Electromagnetic Interference Shielding

Abstract: Single-walled carbon nanotube (SWNT)/poly(methyl methacrylate) (PMMA) composites were prepared using coagulation method. The electrical conductivity and the electromagnetic interference (EMI) shielding of SWNT/PMMA composites over the X-band (8–12 GHz) and the microwave (200–2000 MHz) frequency range have been investigated. The electrical conductivity of composites increases with SWNT loading by 13 orders of magnitude, from 10−15 to 10−2 Ω−1 cm−1 with a percolation threshold of about 3 wt% SWNTs. The effect of the sample thickness on the shielding effectiveness has been studied, and correlated to the electrical conductivity of composites. The data suggest that SWNT/PMMA composites containing higher SWNT loading (above 10 wt%) be useful for EMI shielding and those with lower SWNT loading be useful for electrostatic charge dissipation. The dominant shielding mechanism of SWNT/PMMA composites was also discussed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

The Other Re‐engineering of Engineering Education, 1900–1965

Abstract: Many engineering colleges in the 1990s are busily revising the style and substance of engineering curricula to provide increased attention to design. The intent is to redress what many reformers see as an imbalance caused by too much emphasis on the analytical approaches of engineering science. In effect, current reforms are responding to changes made in American engineering colleges in the years immediately after World War II, when engineering curricula first fully embraced an analytical mode of engineering science. This paper examines how and why this earlier “re-engineering” of engineering education came to pass. It begins by summarizing the state of engineering education in the late 19th century. Then the paper discusses the role of European-born and educated engineers such as Stephen Timoshenko, Theodore von Kermen, and Harald Westergaard, who after 1920 prepared the ground for the later transformation of engineering curricula. The paper next discusses the efforts of leaders such as Solomon Cady Hollister and Eric Walker to introduce changes after 1945, and concludes by noting how their initial visions of curricula based on engineering science were altered during implementation.

Electrocatalytic oxidation of glycerol on Pt/C in anion-exchange membrane fuel cell: Cogeneration of electricity and valuable chemicals

Abstract: Electrocatalytic oxidation of glycerol for cogenerating electricity and higher-valued chemicals on a Pt/C anode catalyst (2.4 nm) in an anion-exchange membrane fuel cell (AEMFC) was investigated. The peak power density of an anion-exchange membrane – direct glycerol fuel cell (AEM-DGFC) with 1.0 mgPt cm−2 anode and non-PGM catalyst cathode can reach 124.5 mW cm−2 at 80 °C and 58.6 mW cm−2 at 50 °C, while the highest selectivity of C3 acids (glyceric acid + tartronic acid) can reach 91%. The study found that higher pH reaction media could enhance fuel cell output power density (electricity generation) and selectivity of C3 acids, while lower glycerol concentration could improve the selectivity of deeper-oxidized products (mesoxalic acid and oxalic acid). The fuel cell reactor with the Pt/C anode catalyst demonstrated an excellent reusability, and successfully obtained tartronic acid with a selectivity of 50% and mesoxalic acid with a selectivity of 7%, which are high compared to heterogeneous catalytic glycerol oxidation in batch reactors. It is found that the anode overpotential can regulate the oxidation product distribution, and that higher anode overpotentials favor C C bond breaking, thus lowering the C3 acids selectivity. The reaction sequence of glycerol electro-oxidation detected in an electrolysis half cell with an on-line sample collection and off-line HPLC analysis agrees with the results obtained from single fuel cell tests. However, inconsistencies between the two systems still exist and are possibly due to different reaction environments, such as electrode structure, glycerol:catalyst ratio, and residence time of reactants.

Re‐evaluation of SO2 release of the 15 June 1991 Pinatubo eruption using ultraviolet and infrared satellite sensors

Abstract: [1] In this study, ultraviolet TOMS (Total Ozone Mapping Spectrometer) satellite data for SO2 are re-evaluated for the first 15 days following the 15 June 1991 Pinatubo eruption to reflect new data retrieval and reduction methods. Infrared satellite SO2 data from the TOVS/HIRS/2 (TIROS (Television Infrared Observation Satellite) Optical Vertical Sounder/High Resolution Infrared Radiation Sounder/2) sensor, whose data sets have a higher temporal resolution, are also analyzed for the first time for Pinatubo. Extrapolation of SO2 masses calculated from TOMS and TOVS satellite measurements 19–118 hours after the eruption suggest initial SO2 releases of 15 ± 3 Mt for TOMS and 19 ± 4 Mt for TOVS, including SO2 sequestered by ice in the early Pinatubo cloud. TOVS estimates are higher in part because of the effects of early formed sulfate. The TOMS SO2 method is not sensitive to sulfate, but can be corrected for the existence of this additional emitted sulfur. The mass of early formed sulfate in the Pinatubo cloud can be estimated with infrared remote sensing at about 4 Mt, equivalent to 3 Mt SO2. Thus the total S release by Pinatubo, calculated as SO2, is 18 ± 4 Mt based on TOMS and 19 ± 4 Mt based on TOVS. The SO2 removal from the volcanic cloud during 19–374 hours of atmospheric residence describes overall e-folding times of 25 ± 5 days for TOMS and 23 ± 5 days for TOVS. These removal rates are faster in the first 118 hours after eruption when ice and ash catalyze the reaction, and then slow after heavy ash and ice fallout. SO2 mass increases in the volcanic cloud are observed by both TOMS and TOVS during the first 70 hours after eruption, most probably caused by the gas-phase SO2 release from sublimating stratospheric ice-ash-gas mixtures. This result suggests that ice-sequestered SO2 exists in all tropical volcanic clouds, and at least partially explains SO2 mass increases observed in other volcanic clouds in the first day or two after eruption.

MoS2 as a co-catalyst for photocatalytic hydrogen production from water

Abstract: Solar-to-hydrogen conversion based on photocatalytic water splitting is a promising pathway for sustainable hydrogen production. The photocatalytic process requires highly active, inexpensive, and earth-abundant materials as photocatalysts. As a presentative layer-structured transition metal dichalcogenides, molybdenum disulfide (MoS2) is attracting intensive attention due to its unique electro and photo properties. In this article, we comprehensively review the recent research efforts of exploring MoS2 as a co-catalyst for photocatalytic hydrogen production from water, with emphasis on its combination with CdS, CdSe, graphene, carbon nitride, TiO2, and others. It is shown that MoS2–semiconductor composites are promising photocatalysts for hydrogen evolution from water under visible light irradiation.