4,369 research outputs found
Preparation and characterization of carbamoylethyl hemicelluloses
No full textThe reaction of hemicelluloses, isolated from wheat straw, with acrylamide in alkaline aqueous solution was investigated. The degree of substitution (DS, up to 0.65) of the products could be obtained by adjusting the molar ratios of reagent to xylose unit in hemicelluloses (1.0-10.0) and the molar ratios of catalyst to xylose unit in hemicelluloses (0.5-1.6). Changes in the structure of hemicelluloses were verified by FT-IR and 1H and 13C NMR spectroscopies. The results showed that carbamoylethyl groups surely were grafted onto the main chain of hemicelluloses. Moreover, it was also found that the saponification of carbamoylethyl groups to carboxyl groups occurred in alkaline medium. The behavior of modified hemicelluloses was monitored by means of thermo gravimetry (TG) and differential thermal analysis (TGA). It was found that the products had a lower thermal stability than the native hemicelluloses
R.C. Farrell Store
No full textPhotograph - People standing in front of R.C. Farrell, General Merchant store, Athabasca, Alberta. Left to right: Lance Smith, Louis Menard, Romeo Farrell, Athela LaRue Farrell, and Ray Vari
Simulation of Electrostatic Oil Line Sensing and validation using experimental results
No full textElectrostatic Oil Line Sensor (OLS) is one type of the electrostatic sensors based on electrostatic charging phenomenon and has been used in wear debris monitoring in oil lubricated tribological systems. With the advantages of high sensitivity and resolution, OLS has been proved to be an effective sensing technique for sliding, rolling and bearing contacts. However the sensing technique has so far not been widely used in industrial systems due to the difficulties in identify the exact charge sources and charging mechanisms in a complex tribological system. This paper presents the results from a simulation of the sensing mechanisms that is successfully validated by experimental results. The initial OLS simulation results have led to a better sensor design and its application
A Review of: Biobloc Therapy, by John R.C. Mew
No full textThis text, written and published by its British author, John R.C. Mew, details an integrated orthodontic and orofacial myofunctional treatment approach entitled Biobloc Therapy [...
Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane
No full textThe oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attributed to the localised heating of microwave radiation resulting in temperature inhomogeneity in the catalyst bed. A simplified model was used to estimate the temperature inhomogeneity; the temperature at the centre of the catalyst bed was 85 °C greater than that at the periphery when the catalyst was heated by microwaves in a gas mixture with an oxygen concentration of 12.5% (v/v), and the temperature difference was estimated to be 168 °C in the absence of oxygen
An Optimal Rule for Switching over to Renewable fuels with Lower Price Volatility: A Case of Jump Diffusion Process
No full textThis study investigates the optimal switching boundary to a renewable fuel when oil prices exhibit continuous random fluctuations along with occasional discontinuous jumps. In this paper, oil prices are modeled to follow jump diffusion processes. A completeness result is derived. Given that the market is complete the value of a contingent claim is risk neutral expectation of the discounted pay off process. Using the contingent claim analysis of investment under uncertainty, the Hamilton-Jacobi-Bellman (HJB) equation is derived for finding value function and optimal switching boundary. We get a mixed differential-difference equation which would be solved using numerical methods.Demand and Price Analysis, Resource /Energy Economics and Policy,
Evaluation of Sun Glint Correction Algorithms for High-Spatial Resolution Hyperspectral Imagery
No full textSun glint correction algorithms were tested on a hyperspectral image containing cross-track sun glint. Spatial profiles of pixel radiance by pixel position were compared and slope values were calculated. The algorithms of Hedley et al., Lyzenga et al., and Joyce over-corrected for sun glint in the visible and near-infrared wavelengths. The method proposed by Kuster et al. was the weakest performer during visual comparison with the other method results. Spectral plots of corrected spectra to the original spectra were compared. Comparisons were performed on spectra from pixels with low and high amounts of sun glint. Spectra were compared within the sun glint corrected images and between the corrected images and the original image. Correlation values were calculated for each spectral comparison and averaged for each sun glint correction algorithm. The Lyzenga et al. sun glint correction algorithm had the highest average correlation value of 0.977 and is recommended for reducing sun glint in hyperspectral imagery when spectral integrity is required.Approved for public release; distribution is unlimited.Civilian, Department of the Navyhttp://archive.org/details/evaluationofsung109451742
Experimental performance evaluation of line-focus sun trackers
No full textTwo sun trackers have been tested for tracking accuracy on an sun tracker. Both performed well during the entire test period. Their tracking performance as a function of insolation level was established, and their overall tracking accuracy (rms tracking error) was calculated. Both the flux-line and the shadowband tracker were found to have an effective rms error of about 1 milliradian. This information was used to determine the impact that the two trackers have on the annual energy performance of typical parabolic trough concentrating collectors. One milliradian rms tracking errors were found to result in negligibly small annual performance losses
Experimental Research and Numerical Analysis on the Law of Deteriorated Performance for R.C. Frame Structure with Seismic Damages under Elevated Temperature (part II)
No full textThe cracks were pre-settled to the R.C. frame structure caused by earthquake which was defined as the damage index ω during the modeling process with analysis software-ANASYS. The temperature field contour curve were calculated for the column and beam, the law of deteriorated bearing capacity with time for the R.C. frame structure under elevated temperature were brought forward，which can adapt to R.C. frame structure with different damage index ω caused by earthquake.The relationship between ω and deteriorated bearing capacity for R.C. frame structure was also given, which was proved to be effective and correct according to comparison with the data recorded from the elevated temperature experiment designed by author.</jats:p
Internal Friction in The Region of The Grain Boundary Peaks in Pure Zirconium and Dilute Zirconium Alloys
No full textTitle: Internal Friction in The Region of The Grain Boundary Peaks in Pure Zirconium and Dilute Zirconium Alloys, Author: R.C. Robinson, Location: ThodeInternal friction, in the region of the
grain boundary peaks, has been examined in nominally
pure zirconium and dilute zirconium alloys. Experimental
observations were made using both torsion and
reed internal friction pendulums. The effect of various
heat treatments on the peaks were investigated. Strain
amplitude dependent damping in the region of the Low
Temperature Peak was observed. A qualitative model
is presented to explain the experimental observations.ThesisMaster of Engineering (ME
- …
