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31.
Oster Timothy A 《精细化工原料及中间体》2014,(8)
正专利披露了制造5-硫代异对苯二甲酸的单-锂盐(LiSIPA),该化合物含硫酸根低于500×10-6。过程使用反应混合物,其包含水,产生锂阳离子的化合物,和5-硫代异-对苯二甲酸。反应混合物加热回流,冷却,过滤和用醋酸洗涤,得到含硫酸根低于500×10-6的高质量的LiSIPA。 相似文献
32.
Several studies have utilized “leading points” concepts to explain the augmentation of burning rates in turbulent flames by flow fluctuations. These ideas have been particularly utilized to explain the strong sensitivity of turbulent burning rates to fuel composition. Leading point concepts suggest that the burning velocity is controlled by the velocity of the points on the flame that propagate farthest out into the reactants – thus, they de-emphasize the classical idea that burning velocity enhancement is due to increases in flame surface area. Rather, within this interpretation, flame area creation is the effect, not the cause, of augmented turbulent burning velocities. However, the theory behind the implementation of leading point concepts in turbulent combustion modeling needs further development and the definition of “leading point” has not been fully clarified. For a certain class of steady shear flows, it is straightforward to demonstrate the leading point concept in an intuitive manner, but the problem becomes more complex when the leading points themselves evolve in time. In this paper, we use the G-equation to describe the flame dynamics and, utilizing results for Hamilton–Jacobi equations from the Aubry–Mather theory, demonstrate both the utility and limitations of leading points interpretations for front propagation, at least for deterministic problems. Specifically, we show how the large-time behavior of the solutions is controlled by discrete points on the flame under certain conditions and is, therefore, independent of the rest of the flow field details – a key hypothesis of leading points theories. However, it is possible to find other conditions where the large time behavior of the flame is not controlled by discrete points on the flame, but rather by the velocity field over its entire surface. Moreover, we also show that even in cases where the burning rate is controlled by discrete points, these points are not necessarily the most forward lying points in the flame front. Finally, we consider the case where the laminar flame speed is a function of flame front curvature and derive exact results for the sensitivity of the front speed to the Markstein length, ?, for ? > 0. These solutions explicitly illustrate how the reduction of front displacement speed for increasing ? can be interpreted in terms of leading points dynamics in some cases. 相似文献
33.
Angelique A. Scharine Mary S. Binseel Timothy Mermagen Tomasz R. Letowski 《Ergonomics》2014,57(8):1222-1243
Helmets provide soldiers with ballistic and fragmentation protection but impair auditory spatial processing. Missed auditory information can be fatal for a soldier; therefore, helmet design requires compromise between protection and optimal acoustics. Twelve soldiers localised two sound signals presented from six azimuth angles and three levels of elevation presented at two intensity levels and with three background noises. Each participant completed the task while wearing no helmet and with two U.S. Army infantry helmets – the Personnel Armor System for Ground Troops (PASGT) helmet and the Advanced Combat Helmet (ACH). Results showed a significant effect of helmet type on the size of both azimuth and elevation error. The effects of level, background noise, azimuth and elevation were found to be significant. There was no effect of sound signal type. As hypothesised, localisation accuracy was greatest when soldiers did not wear helmet, followed by the ACH. Performance was worst with the PASGT helmet. 相似文献
34.
Morphologically dependent alternating‐current and direct‐current breakdown strength in silica–polypropylene nanocomposites 下载免费PDF全文
Timothy Krentz Mohammad M. Khani Michael Bell Brian C. Benicewicz J. Keith Nelson Su Zhao Henrik Hillborg Linda S. Schadler 《应用聚合物科学杂志》2017,134(1)
In this article, we report the synthesis of a new bimodal surface ligand morphology on silica nanoparticles. Combining grafting‐to and grafting‐from approaches, in this study, we demonstrated the efficacy of anthracene surface modification for improving the dielectric breakdown strength (DBS) under alternating‐current and direct‐current conditions and that of a matrix‐compatible polymer brush for controlling the nanofiller (NF) dispersion. Ligand‐modified spherical colloidal SiO2 nanoparticles (~14 nm in diameter) were mixed into polypropylene, and the resulting dispersion was improved over the unmodified particles, as shown with transmission electron microscopy. The results suggest that the electronic structure of the anthracene‐modified particle surface was critical to the improvement in DBS. In addition, the DBS of the composite was shown to depend on the dispersion state of the filler and the mode of stress; this indicated that the individually dispersed nanoparticles were not necessarily the optimal morphology for all stress conditions. Additionally, the precise nature of the matrix‐compatible brush was less important than the NF dispersion it produced. The bimodal grafted architectural design has provided a promising solution for the control of the dispersion and surface properties, especially for high‐molecular‐weight polymer matrices. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44347. 相似文献
35.
Baobab fruit shell (BFS), a renewable bio-waste from Malawian baobab tree was used as a precursor for the production of a low-cost activated carbon to remove methylene blue (MB) from aqueous solution. Parameters such as contact time, initial methylene blue concentration, adsorbent dose and temperature were studied. The adsorption process can be well described by both Langmuir isotherm and the pseudo-second-order kinetics. The maximum monolayer adsorption capacity of MB dye was ca. 334.45 mg/g. The negative value of the Gibb’s free energy and positive value of adsorption enthalpy showed the spontaneous nature and endothermic nature of the adsorption process, respectively. 相似文献
36.
37.
Balraj Singh Daniel Abriola Coral Baglin Vivian Demetriou Timothy Johnson Elizabeth McCutchan Gopal Mukherjee Sukhjeet Singh Alejandro Sonzogni Jagdish Tuli 《Nuclear Data Sheets》2013,114(6-7):661-749
The evaluated spectroscopic data are presented for 11 known nuclides of mass 211 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th). The 211Pa nuclide is included here but its identification remains uncertain. For 211Hg, 211Tl, 211Ac and 211Th nuclei, only the ground–state information is available. Their decay characteristics are mostly unknown. 211Fr is suggested to decay partially through ε decay mode, but its decay scheme remains poorly known. While high–spin excitations, including several isomers, are well studied in 211Pb, 211Bi, 211Po, 211At, 211Rn and 211Fr, the particle–transfer data are available for only 211Po and 211Bi.This evaluation was carried out as part of joint IAEA–ICTP workshop for Nuclear Structure and Decay Data, organized and hosted by the IAEA, Vienna and ICTP, Trieste, August 6–17, 2012. This work supersedes previous A=211 evaluation (2004Br45) published by E. Browne which covered literature before January 2003. 相似文献
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39.
Jay Sagin Anton Sizo Howard Wheater Timothy D. Jardine 《International journal of remote sensing》2013,34(3):764-781
Tracking surface water coverage changes is a complicated task for many regions of the world. It is, however, essential to monitor the associated biological changes and bioproductivity. We present a methodology to track contemporary water coverage changes using optical remote sensing and use it to estimate historical summer water coverage in a large river delta. We used a geographical information system automated routine, based on the modified normalized difference water index, to extract the surface water coverage area (SWCA) from optical satellite data sets using the surface water extraction coverage area tool (SWECAT). It was applied to measure SWCA during drought and flood peaks in the Saskatchewan River Delta in Canada, from Landsat, SPOT and RapidEye images. Landsat results compared favourably with Canadian National Hydro Network (CNHN) GeoBase data, with deviations between SWCA classifications and the base CNHN GeoBase shapefile of ~2%. Difference levels between the extracted SWCA layer from Landsat and the higher resolution commercial satellites (SPOT and RapidEye) were also less than 2%. SWCA was tightly linked to discharge and level measurements from in-channel gauges (r2 > 0.70). Using the SWCA versus discharge relationship for the gauge with the longest record, we show that peak summer SWCA has declined by half over the last century, from 13% of our study area to 6%, with likely implications for fish and wildlife production. 相似文献