Hasil untuk "Technology"

M. Porter

Dorothy Leonard-Barton

C. May

T. Allen

P. Kalberla, W. B. Burton, D. Hartmann et al.

We present the final data release of observations of ?21-cm emission from Galactic neutral hydrogen over the entire sky, merging the Leiden/Dwingeloo Survey (LDS: Hartmann & Burton 1997, Atlas of Galactic Neutral Hydrogen) of the sky north of ? = ?30? with the Instituto Argentino de Radioastronomia Survey (IAR: Arnal et al. 2000, AA and Bajaja et al. 2005, A&A, 440, 767) of the sky south of ? = ?25?. The angular resolution of the combined material is HPBW ? 0. ?6. The LSR velocity coverage spans the interval ?450 km s?1 to +400 km s?1, at a resolution of 1.3 kms?1. The data were corrected for stray radiation at the Institute for Radioastronomy of the University of Bonn, refining the original correction applied to the LDS. The rms brightness-temperature noise of the merged database is 0.07?0.09 K. Residual errors in the profile wings due to defects in the correction for stray radiation are for most of the data below a level of 20?40 mK. It would be necessary to construct a telescope with a main beam efficiency of ?MB >? 99% to achieve the same accuracy. The merged and refined material entering the LAB Survey of Galactic HI is intended to be a general resource useful to a wide range of studies of the physical and structural characteristices of the Galactic interstellar environment. The LAB Survey is the most sensitive Milky Way HI survey to date, with the most extensive coverage both spatially and kinematically.

J. Delcour, R. Hoseney

Magnus Blomstrom, Magnus Blomstrom, Magnus Blomstrom et al.

Knut Skumsvoll, Knut Skumsvoll

nence. Incorporating the crosslinking system into the coating medium is the simplest manner of operation. However, such a procedure can greatly reduce the workability of the coating due to shortened pot life of the material. Basically, the coating begins to crosslink and change before it is applied to the substrate. A relatively simple but effective method of delivering the crosslinking component to the coated substrate has been developed by a research group from Eastman Kodak (U.S. Patent 6,071,688; June 6, 2000). This involves vapor deposition of the crosslinker in an separate layer on top of the coating. In the specific process used by Eastman, a stream of nitrogen gas was saturated with trimethyl borate, the crosslinking agent. This agent reacted with hydroxyl groups on poly(vinyl butyral), used as the major constituent of the coating. The saturated vapor was bathed onto the surface of the coating, so that a small amount of the trimethyl borate is deposited on the coating. The researchers point out that this method is different from atomized deposition methods, by the absence of defects formed by droplets on the coating. — INJ RESEARCHER’S TOOLBOX

M. S. Shetty

R. Brow

W. Höland, G. Beall

Hengying Zhu, M. Snyder

Joseph S. Friedman, Jonathan Silberman

R. Reis, A. Zydney

D. Mills

A. Willig, K. Matheus, A. Wolisz

Paul Saettler

The primary purpose of this book is to trace the theoretical methodological foundations of American educational technology. It must be emphasized that this work is essentially as history of the process of educational technology rather than of products in the form of devices or media. Although media have played an important rode in educational technology, the reader should not lose sight of the central process which characterizes and underlies the true historical meaning and function of educational technology. Moreover, the assumption is made that all current theory, methodology, and practice rests upon the heritage of the past. Indeed, a common problem in the field has been the failure, in many instances, to take adequate account of past history in planning for the present or the future. A related purpose of this book is to provide a selective survey of research in educational technology as it relates to the American public schools. Such research reviews are not intended to be comprehensive, but were included because of their historical importance and their relevance in understanding the process of educational technology.

S. Judd

Gengyang Li, Mason Peng, Qingguo Huang et al.

Per- and polyfluoroalkyl substances (PFAS) have drawn public concern recently due to their toxic properties and persistence in the environment, making it urgent to eliminate PFAS from contaminated water. Electrochemical oxidation (EO) has shown great promise for the destructive treatment of PFAS with direct electron transfer and hydroxyl radical (⋅OH)-mediated indirect reactions. One of the most popular electrodes is Magnéli phase titanium suboxides. However, the degradation mechanisms of PFAS are still unsure and are under investigation now. The main methodology is the first-principal density functional theory (DFT) computation, which is recently used to explore the degradation mechanisms and interpret by-product formation during PFAS mineralization. From the literature review, the main applications of DFT computation for studying PFAS degradation mechanisms by EO include bond dissociation energy, absorption energy, activation energy, and overpotential η for oxygen evolution reactions. The main degradation mechanisms and pathways of PFAS in the EO process include mass transfer, direct electron transfer, decarboxylation, peroxyl radical generation, hydroxylation, intramolecular rearrangement, and hydrolysis. In the recent 4 years, 11 papers performed DFT computation to explore the possible PFAS degradation mechanisms and pathways in the EO process. This paper’s objectives are to: 1) summarize the main degradation mechanisms of PFAS degradation in EO; 2) review the application of DFT computation for studying PFAS degradation mechanisms during EO; process; 3) review the possible degradation pathways of perfluorooctane sulfonoic acid (PFOS) and per-fluorooctanoic acid (PFOA) during EO process.

Tobias Heimann, Lara-Sophie Wähling, Tomke Honkomp et al.

Bioenergy with carbon capture and storage (BECCS) is a crucial element in most modelling studies on emission pathways of the Intergovernmental Panel on Climate Change to limit global warming. BECCS can substitute fossil fuels in energy production and reduce CO _2 emissions, while using biomass for energy production can have feedback effects on land use, agricultural and forest products markets, as well as biodiversity and water resources. To assess the former pros and cons of BECCS deployment, interdisciplinary model approaches require detailed estimates of technological information related to BECCS production technologies. Current estimates of the cost structure and capture potential of BECCS vary widely due to the absence of large-scale production. To obtain more precise estimates, a global online expert survey ( N = 32) was conducted including questions on the regional development potential and biomass use of BECCS, as well as the future operating costs, capture potential, and scalability in different application sectors. In general, the experts consider the implementation of BECCS in Europe and North America to be very promising and regard BECCS application in the liquid biofuel industry and thermal power generation as very likely. The results show significant differences depending on whether the experts work in the Global North or the Global South. Thus, the findings underline the importance of including experts from the Global South in discussions on carbon dioxide removal methods. Regarding technical estimates, the operating costs of BECCS in thermal power generation were estimated in the range of 100–200 USD/tCO _2 , while the CO _2 capture potential was estimated to be 50–200 MtCO _2 yr ^−1 by 2030, with cost-efficiency gains of 20% by 2050 due to technological progress. Whereas the individuals’ experts provided more precise estimates, the overall distribution of estimates reflected the wide range of estimates found in the literature. For the cost shares within BECCS, it was difficult to obtain consistent estimates. However, due to very few current alternative estimates, the results are an important step for modelling the production sector of BECCS in interdisciplinary models that analyse cross-dimensional trade-offs and long-term sustainability.