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131.
Pollock P. Yu L. Sutton M. A. Guo S. Majumdar P. Gresil M. 《Experimental Techniques》2014,38(4):61-71
Experimental Techniques - Using theoretical formulations to describe the general response of an orthogonally woven glass-epoxy composite subjected to off-axis tension loading, a simple experimental... 相似文献
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This Letter presents results from a new master-oscillator, power-amplifier pulse-burst laser system demonstrating ultrahigh pulse energies greater than 2.0 J/pulse at 1064?nm with interpulse separations of 100?μs (10?kHz) for burst durations of 100 pulses. Each pulse generates peak powers exceeding 130?MW and an average power of approximately 20?kW is generated over a 100-pulse-burst. Pulse energies decrease by less than 10% over a 100 sequential pulses, demonstrating negligible "droop" over long-duration pulse trains. Second-harmonic generation of 532?nm with conversion efficiency greater than 50% is demonstrated for 100-pulse-burst durations. 相似文献
134.
Karina Fraige R. Dario Arrua Adam T. Sutton Cristiano Soleo Funari Alberto Jos Cavalheiro Emily F. Hilder Vanderlan da Silva Bolzani 《Journal of separation science》2019,42(2):591-597
Natural deep eutectic solvents have been used as an alternative to organic solvents for the extraction of plants metabolites, allowing for the extraction of compounds of different polarities, while being inexpensive, non‐toxic, and easy to prepare. This work presents the comparison of the chromatographic profiles by high‐performance liquid chromatography with diode‐array detection obtained from Byrsonima intermedia (Malpighiaceae) using five choline chloride‐based natural deep eutectic solvents, in addition to the most used traditional extraction solvents, methanol/water 7:3 and ethanol/water 7:3 v/v. A reference extract was used to tentatively identify compounds by high‐performance liquid chromatography with tandem mass spectrometry. The water content appeared to be important for the extraction efficiency and the mixture choline chloride/glycerol was shown to be the best candidate for efficiently extracting this matrix when compared with the traditional extraction media in addition to being far greener as shown by the environmental analysis tool. Seven phenolic compounds (digalloyl quinic acid, proanthocyanidin dimer, galloylproanthocyanidin dimer, quercetin‐O‐hexoside, galloyl quercetin hexoside, quercetin‐O‐pentoside, and galloyl quercetin pentoside) were tentatively identified in all extracts. Moreover, the influence of these solvents on the antioxidant activity of the extracts was studied and the results for choline chloride/glycerol extracts were very similar to that of the traditional extraction solvents. 相似文献
135.
Sub‐microsecond‐resolved multi‐speckle X‐ray photon correlation spectroscopy with a pixel array detector
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Qingteng Zhang Eric M. Dufresne Suresh Narayanan Piotr Maj Anna Koziol Robert Szczygiel Pawel Grybos Mark Sutton Alec R. Sandy 《Journal of synchrotron radiation》2018,25(5):1408-1416
Small‐angle X‐ray photon correlation spectroscopy (XPCS) measurements spanning delay times from 826 ns to 52.8 s were performed using a photon‐counting pixel array detector with a dynamic range of 0–3 (2 bits). Fine resolution and a wide dynamic range of time scales was achieved by combining two modes of operation of the detector: (i) continuous mode, where data acquisition and data readout are performed in parallel with a frame acquisition time of 19.36 µs, and (ii) burst mode, where 12 frames are acquired with frame integration times of either 2.56 µs frame?1 or 826 ns frame?1 followed by 3.49 ms or 1.16 ms, respectively, for readout. The applicability of the detector for performing multi‐speckle XPCS was demonstrated by measuring the Brownian dynamics of 10 nm‐radius gold and 57 nm‐radius silica colloids in water at room temperature. In addition, the capability of the detector to faithfully record one‐ and two‐photon counts was examined by comparing the statistical distribution of photon counts with expected probabilities from the negative binomial distribution. It was found that in burst mode the ratio of 2 s to 1 s is markedly smaller than predicted and that this is attributable to pixel‐response dead‐time. 相似文献
136.
S. Rajan M. A. Sutton D. C. Rizos A. R. Ortiz A. Zeitouni J. M. Caicedo 《Experimental Mechanics》2018,58(7):1035-1048
This work proposes a novel, stereo-vision based test setup for the accurate measurement of relatively small surface strain fields that develop in prestressed concrete prismatic beams after strand release, with the goal of providing an effective and accurate alternative to existing measurement techniques. To this end, the enclosed paper discusses the proposed StereoDIC system configuration, introduces the technique for acquiring full-field shape, deformation and strain measurements using 3D Digital Image Correlation (StereoDIC), verifies the proposed technique through high fidelity laboratory and computer simulations and proposes a computational algorithm that automates the calculation of the transfer length using these measurements. Our studies show that the proposed approach is an effective and accurate non-contacting technique for determining the small surface strain fields in full-scale, prestressed concrete beam specimens, providing essential data to reliably estimate the transfer length in prestressed concrete beams. Though implementation of the procedure in industrial scale facilities is beyond the scope of this paper, discussion regarding this extension is provided. 相似文献
137.
In the current study, the auto-ignition dynamics of cold fuel jets issuing into a high-temperature, vitiated environments is investigated. Due to the short time scale of these events, high-speed measurements are used to resolve the coupled spatio-temporal behavior. The present study uses high-speed (20-kHz) OH* chemiluminescence imaging to identify the location and timing of the formation of the initial ignition kernels, providing visualization of the ignition dynamics and a detailed statistical evaluation of ignition heights and ignition delay times across a broad parameter space which includes variations in fuel type, dilution levels, coflow temperature, and coflow oxidizer content. The auto-ignition location and ignition delay times show a strong sensitivity to coflow temperature with increased sensitivities at lower coflow temperatures. Comparisons between kernel formation location for the transient jet and the fluctuating flame base of the subsequent, steady-state flame is presented, highlighting the role of flame propagation on flame stabilization. Results indicate that at lower temperatures the flame stabilization mechanism is dominated by auto-ignition, but at higher coflow temperatures, flame propagation plays a key role. The effects of variations in the hot, coflow oxidizer content on ignition properties were found to be noticeable, but still significantly less than variations in the temperature. 相似文献
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Bisaryl-8H-imidazo[2,1-c][1,4]thiazines were prepared from the corresponding 2-thiomethylimidazoles. A novel and efficient synthesis is presented for these intermediates based on the condensation of benzils with protected 2-thioacetaldehydes. 相似文献
140.