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941.
Roman Werner Bernadette Bollwein Roman Petersen Johannes Tippmann Thomas Becker 《化学工程与技术》2017,40(3):450-458
The cleaning of filter cloths is necessary to avoid prolonged system downtime and strong fouling. Reliable cleaning concepts are central to the removal of residues from the complex surface of filter cloths. Particle residues, in particular, play a decisive role in the sufficiency of the cleaning performance. Consequently, enhanced particle‐removal cleaning concepts based on pulsatile jets for filter cloths have been developed. By varying the cleaning parameters, it has been demonstrated that increased pulse numbers and velocities improve the cleaning performance. Furthermore, this promising cleaning concept cleaned more effectively than conventional methods. The reduction in the amount of detergent needed is an ecological and economic advantage of pulsatile cleaning. 相似文献
943.
944.
Thermal analysis of randomly oriented carbon nanotube reinforced functionally graded timoshenko beam
Benedict Thomas Prasad K. Inamdar Tarapada Roy 《Journal of Mechanical Science and Technology》2014,28(5):1779-1788
The unique thermal properties of carbon nanotubes (CNT) are utilized to increase the use of functionally graded material (FGM) at higher temperatures which resulted in introduction of a new type of material called as functionally graded carbon nanotube-reinforced composites (FG-CNTRCs). To use the FG-CNTRCs at elevated temperatures, their thermal analysis is very important. In this context, this article presents the thermal analysis of a CNT based FG Timoshenko beam. Material properties distribution is assumed to vary along the thickness direction according to power law distribution and linear distributions. Finite difference method is implemented to find out the temperature distribution. Using first order shear deformation theory (FSDT), expressions for strains and stresses are obtained. The results are compared with temperature distribution according to power law. The effect of CNT distribution on strains and stresses is also observed. Based on these results important conclusions have been drawn. 相似文献
945.
The fact that the smoothing error is a (wide sense) Markov process is somehow surprising since smoothed estimates depend upon both past and future data. In this paper we first give a simple and general proof of this fact. Then we use the so-called complementary models introduced by Weinert and Desai to derive forwards and backwards markovian models for the smoothing error in state-space models. By exploring the structure of the complementary models we show that, under certain restrictions, only two simple structured models exist, one that runs forwards in time and the other that runs backwards in time. The forwards complementary model leads to the forward Rauch-Tung-Striebel (RTS) smoothing formula and to a backwards markovian model for the error, whereas the backwards model leads to the backward RTS formula and to a forwards error model. The two models for the smoothing error can be derived one from the other by a forward-backward transformation that preserves the sample paths. Finally, by using a combination of the two complementary models we give yet another proof for the two-filter smoothing formula. 相似文献
946.
Arun Kumar K V Revathy K P Prathibha Vasudevan Sunil Thomas Biju P R Unnikrishnan N V 《中国稀土学报(英文版)》2013,31(5):441-448
We reported here the structural and optical characterisation of silver nanocrystallites/Eu3+ :SiO2-TiO2 matrices synthesised through sol-gel route. Structural characterisations were done by using energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscope (AFM) and transmission electron microscopy (TEM) measurements and optical characterisations were performed by absorption and emission spectroscopy. The TEM and XRD measurements confirmed the presence of nanocrystals. A broad absorption band was observed due to surface plasmon resonance of silver nanocrystals. The effect of silver nanocrystals on the emission spectrum of Eu3+ doped SiO2-TiO2 matrices was discussed. An attempt was made to explain this fluorescence enhancement by invoking phenomena such as energy transfer, asymmetry ratio, surface plasmon, surface roughness, crystallinity and grain boundary. Our analysis, based on the experimental results, suggested that all the phenomena except crystallinity and grain boundary had favourable effects on fluorescence enhancement. We also estimated the relevant parameters associated with the phenomena that affected the fluorescence emission from the Eu3+ ions in the matrix. It was seen that the theoretical estimate of fluorescence enhancement agreed well with the experimental estimate. 相似文献
947.
Daba S. Gedafa Mustaque Hossain Richard Miller Thomas Van 《International Journal of Pavement Engineering》2014,15(4):309-322
The Kansas Department of Transportation has a comprehensive pavement management system known as network optimisation system (NOS). Annual condition surveys are conducted for NOS. Currently, the structural number (SN) of flexible pavements is computed using the American association of state highway and transportation officials equation based on the centre and fifth sensor deflections of a falling weight deflectometer (FWD). However, a rolling wheel deflectometer (RWD) can be used to collect deflection data at the network-level. This study was conducted to see whether the SN of flexible pavements can be obtained from this RWD deflection and NOS condition survey results. In this study, FWD deflection data, collected from 1998 to 2006, were analysed. Multiple regression analysis was done. The results showed that there is a negative relationship between SN and centre deflection. Equations can be used to calculate SN based on FWD (or RWD) centre deflections and network-level condition survey results. The SN is more sensitive to centre deflection than the total pavement thickness. 相似文献
948.
Flame-assisted spray pyrolysis (FASP) is a versatile process for synthesis of nanoparticles from a broad choice of precursors and solvents. Water is an attractive solvent particularly for inexpensive inorganic precursors (e.g. metal nitrates) as it can effectively reduce the process cost. Furthermore when water usage is combined with a carbon-free fuel (e.g. H2), nanoparticles can be made without forming CO2. Here such a FASP process is explored for synthesis of Bi2O3 and other oxide nanoparticles from aqueous precursor solutions. The flame temperature was measured by FTIR emission–transmission spectroscopy while powders were characterized by X-ray diffraction and N2 adsorption. At low FASP fuel gas (H2 or C2H2) flow rates or process temperatures, product powders had a bimodal crystal size distribution. Its large and small modes were made by droplet- and gas-to-particle conversion, respectively. Homogeneous Bi2O3 and CeO2 powders were obtained for sufficiently high flow rates of either C2H2 or H2. Prolonged high temperature residence times promoted precursor evaporation from the spray droplets and yielded homogeneous nanostructured powders by gas-to-particle conversion. In contrast, FASP of aqueous solutions of aluminum nitrate yielded rather large particles by droplet-to-particle conversion at all fuel flows investigated. 相似文献
949.
Laser operation of a fibre-like 1.1 at.% Nd-doped yttrium aluminium garnet rod with a diameter of 0.34 mm and a length of 4.7 mm has been demonstrated. The fibre was end pumped with 0.5 W of continuous-wave radiation from a laser diode emitting at 808 nm. The measured laser thresholds are in a reasonable agreement with theoretical estimations. The distributions of temperature and stress in the crystal fibre were calculated with finite-element simulations showing that the fibre can be pumped up to a power of 40–50 W without fracture caused by thermal stress. The advantages and disadvantages of the proposed laser rod design are discussed. 相似文献
950.
Extra-label use of veterinary medications in apiculture is a practice which is known to result in the presence of drug residues in honey. Erythromycin has been used by some beekeepers in an attempt to control foulbrood diseases in honey bees. It is recognised that erythromycin degrades in acidic aqueous solutions to yield predominantly anhydroerythromycin. Honey is an acidic medium in which erythromycin should also degrade. Three degradation products with a molecular weight of 715 Da (anhydroerythromycin, erythromycin enol ether, and an unidentified but suspected related isomer) have been confirmed to be formed in honey. Erythromycin was found to degrade rapidly in honey at typical hive temperature with a half-life of less than one day. Based on these results, it is recommended that food safety laboratories include degradation products in analytical testing protocols when examining honey for erythromycin residues. 相似文献