Regional Analysis of Nonmethane Volatile Organic Compounds in the Lower Troposphere of the Southeast United States

Nonmethane organic compounds (NMOCs) along with ozone as well as other trace gas and meteorological parameters were measured at eight rural sites located in the Southeast United States, as part of the Southern Oxidants Study. Fifty-four C2–C10 NMOCs were collected from 1,200–1,300 local time, once every six days from September 1992 through October 1993 and intermittently during 1994. This study was undertaken to characterize the nonmethane hydrocarbons in the rural areas of Southeast United States with respect to their concentrations, reactivities, and relative importance of natural and anthropogenic abundances of NMOCs. Though the sites are well removed from large urban source regions, the observations show a clear anthropogenic influence on the hydrocarbon levels at these rural sites. The data for the sites show similar seasonal patterns for total NMOC with summer maxima (average concentrations of 198 ppbC at the Long Creek, South Carolina, site to 47 ppbC at the Candor, North Carolina site) and fall minima (average concentrations of 73 ppbC at the Long Creek site to 31 ppbC at the Centreville, Alabama site). A secondary maximum is observed during the winter. A seasonal trend was observed in the concentrations of light molecular weight C2–C4 NMOCs (ethane, ethene, acetylene, propane, i-butane, and n-butane) with a winter maximum and a summer minimum. An analysis of changes in C2–C4 hydrocarbon ratios over a period of one year indicates that the variation is most likely due to seasonal changes in OH concentrations. A seasonal trend was also observed for the biogenically emitted NMOC, isoprene, with summer maxima (average concentrations of 37 ppbC at the Long Creek, South Carolina, site to 8.6 ppbC at the Giles County, Tennessee and Metter, Georgia, sites) and winter minima with winter seasonal values below the level of detection. Isoprene was observed to be the most dominant NMOC at most sites during the summer. The ambient concentrations of isoprene measured during the summer were found to be dependent on the ambient temperature. The monoterpenes a-pinene, b-pinene, and d-limonene also peaked during the summer with averages ranging between 3.19 ppbC (Centreville, Alabama) and 6.38 ppbC (Oak Grove, Missouri), and a background concentration of 1.25 to 1.9 ppbC for all the sites during the winter.     

Comparison of international and NEMA standards for salient polesynchronous machines

The Electrical Machinery Committee (EMC) of the Power Engineering Society (PES) of the Institute of Electrical and Electronics Engineers (IEEE) has established a task force charged with the review and comparison of US Standards with international standards with a view to harmonizing these standards. This paper is in response to an assignment from that Task Force. It compares IEC 34 series of standards with National Electrical Manufacturers Association (NEMA) standards for salient pole synchronous machines for nonhydro applications     

食品包装机械制造企业信息化建设存在问题及对策

随着食品包装机械制造企业的快速发展,原有的管理方式已不能满足企业的需求,企业信息化建设将具有关键作用。本文从主客观方面分析了食品包装机械制造企业在进行企业信息化建设中存在的问题着手,提出其实施对策,以期对本行业企业信息化建设提供指导。     

A cost-effective eigensolution method for large systems with Rockwell NASTRAN

The Lanczos method with reorthogonalization based on Householder transformations has been implemented in Rockwell's version of the COSMIC-released NASTRAN program for partial solution of a large-scale symmetric eigenvalue problem. A special technique has been included for restarting Lanczos iteration with a new random vector, partly to avoid premature termination associated with a null or linearly dependent Lanczos feed vector and partly to discover multiple eigenvalues. The developed Lanczos-Householder algorithm with built-in random restart capability shows appreciable cost-savings over the conventional subspace iteration technique as well as the COSMIC NASTRAN method, FEER, which utilizes the modified Gram-Schmidt process to reorthogonalize the Lanczos feed vector with respect to those previously converged.     

Changes in budgetary and personnel support levels of psychology departments, l970–1980.

A survey of US psychology departments that offer graduate programs was conducted during the 1969–1970 academic year and repeated in 1979–1980. Statistics on such topics as the number of undergraduate majors, graduate students, faculty, and secretaries revealed little change over the 10-yr period. However, the number of faculty classroom contact hours increased. While there were increases in many of the budgetary categories, such increases did not keep pace with inflation. Breakdowns of the data by region of the country, public vs private institution, size of university, and type of graduate program (master's degrees only or doctoral degrees) revealed several developments. The most notable include a greater decline in support levels in the western region of the country than in other regions, large gains in the number of graduate students in private institutions, a loss of undergraduates in private institutions, losses in number of faculty in institutions offering only the master's degree, and slight gains in number of faculty in institutions offering doctoral programs. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Near perfect thin film flexible broadband optical absorber with high thermal/electrical conductivity

Flexible ultra-black absorber with high thermal/electrical conductivity finds huge applications in the field of stray light attenuation, solar collectors, flexible electronics, and electronic thermal management systems. In this work, we report the fabrication of ultrablack absorber consists of vertically aligned carbon nanotubes (VACNT) in Polydimethylsiloxane (PDMS) having an absorption capacity of more than 98% in UV–Vis wavelength and more than 94% in NIR wavelength range. It is observed that the PDMS-VACNT composite shows ultra-high absorption capacity due to enhanced impedance matching and multiple scattering. In addition to this, the PDMS-VACNT composite shows an emissivity of 0.94 along with a 118% increase in thermal conductivity. Moreover, with the infiltration of VACNT in PDMS, the sheet resistance decrease drastically to 0.08 KΩ/sq, which signify the possible use of ultrablack absorber in electronic skin and flexible sensors etc. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48855.     

Comparative Analysis of Multi-scale Wavelet Decomposition and k-Means Clustering Based Text Extraction

Wireless Personal Communications - Text present in images provides important information for automatic annotation, indexing and retrieval. Therefore, its extraction is a well-known research area in...