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21.
Michael Lommel Vera Froese Moritz Sieber Marvin Jentzsch Tim Bierewirtz Ümit Hasirci Tim Rese Josef Seefeldt Sebastian Schimek Ulrich Kertzscher Christian Oliver Paschereit 《Indoor air》2021,31(6):1860-1873
The SARS-CoV-2 pandemic has created a great demand for a better understanding of the spread of viruses in indoor environments. A novel measurement system consisting of one portable aerosol-emitting mannequin (emitter) and a number of portable aerosol-absorbing mannequins (recipients) was developed that can measure the spread of aerosols and droplets that potentially contain infectious viruses. The emission of the virus from a human is simulated by using tracer particles solved in water. The recipients inhale the aerosols and droplets and quantify the level of solved tracer particles in their artificial lungs simultaneously over time. The mobile system can be arranged in a large variety of spreading scenarios in indoor environments and allows for quantification of the infection probability due to airborne virus spreading. This study shows the accuracy of the new measurement system and its ability to compare aerosol reduction measures such as regular ventilation or the use of a room air purifier. 相似文献
22.
Adguru Papanna Bharath Ashwath Kumar Kathalsar Soumya Chandrashekhar Pichan Prabhasankar 《International Journal of Food Science & Technology》2021,56(5):2273-2281
The present study aimed to utilise Dicoccum wheat (DW), barley (BF) and soya flour (SF) in the development of low in vitro starch digestibility (IVSD) and estimated glycaemic index (EGI) PB. The BF and SF are mixed (1:1) (BFSF) and used to replace DW at 25%, 50% and 75% level and compared with 100% DW. The quality characteristics (rheological, physical, textural and chemical), IVSD and EGI of PB were determined. The incorporation of BFSF to DW increased the farinograph water absorption capacity (58.1%–64.2%) and mixing tolerance index (21-68 FU), and decreased the dough development time (4.3–2.8 min) and amylograph pasting properties, respectively. Further, the thickness, shear force and redness were decreased and lightness and yellowness increased. Based on the physico-sensory studies, 50% of BFSF along with emulsifier’s incorporation was optimum without affecting any sensory parameters and this PB had decreased IVSD (31) and EGI (54) when compared to the control 37 and 63, respectively. 相似文献
23.
Yang Zhou Ying Wang Jun He Daodong Pan Hongfei Wang Jinxuan Cao 《International Journal of Food Science & Technology》2021,56(1):259-268
In order to investigate the relationship between profile of myofibrillar proteins and tenderness among 2 kinds of Chinese hams (Jinhua and Xuanwei) and 3 kinds of European hams (Iberian, Serrano and Parma), shear force, myofibril fragmentation index (MFI), SDS-PAGE, carbonyls content and Raman spectroscopy were investigated. The shear force and salt content of Chinese hams were significantly higher than that of European hams, while moisture content was lower than that of European hams (p < 0.05). MFI values and SDS-PAGE profile revealed that the degradation of myofibrillar proteins in Chinese hams was lower than in European hams. In addition, Chinese hams showed significantly higher carbonyls content and β-sheet content compared with European hams, indicated that proteins aggregation intensively inhibited the degradation of myofibrillar proteins in Chinese hams. These results indicated that the higher shear force in Chinese style hams could be attributed to the lower moisture content and limited proteolysis. 相似文献
24.
Rita Głowacka Agata Górska Magdalena Wirkowska-Wojdyła Rafał Wołosiak Ewa Majewska Dorota Derewiaka 《International Journal of Food Science & Technology》2019,54(11):3008-3014
The content of bioactive compounds in spent coffee grounds (SGC) was studied. SGC were obtained from Coffea arabica beans of different roasting degrees (light and dark) and different geographical origins (Nicaragua, Columbia and Mexico) processed using four brewing methods (mocha, filtered, drip and infusion). The highest caffeine and chlorogenic acid contents were determined in filtered spent coffee extracts. All extracts of light roasted spent coffee grounds showed lower browning index levels in comparison to that from dark roasted spent coffee grounds. Generally, the highest content of total polyphenolic compounds and highest antioxidant capacity were determined in extracts prepared in drip. In conclusion, the results obtained in this study indicate that the spent coffee grounds produced of domestic levels, especially those obtained from filter coffeemaker, could be considered as a good source of natural antioxidants. 相似文献
25.
Self-adaptive surface measurements that can reduce data redundancy and improve time efficiency are in high demand in many fields of science and technology. For this purpose, a system implemented with Gaussian process (GP) adaptive sampling is developed. The non-parametric GP model is applied to reconstruct the topography and guide the subsequent sampling position, which is determined from the inference uncertainty estimation. A criterion is proposed to terminate the GP adaptive measurement automatically without any prior model or data of the topography. Experiments on typical surfaces validate the intelligence, adaptability, and high accuracy of the GP method along with the stabilization of the automatic iteration termination. Compared with traditional raster sampling, data redundancy is reduced and the time efficiency is improved without sacrificing the surface reconstruction accuracy. The proposed method can be implemented in other systems with similar measurement principles, thus benefitting surface characterizations. 相似文献
26.
Jun Wang Fushuo Wu Ruoan Zou Yueshu Wu Mengdi Gan Jing Feng Xiaoyu Chong 《Journal of the American Ceramic Society》2021,104(11):5873-5882
In this study, high-entropy rare-earth tantalate ceramics (Y0.2Ce0.2Sm0.2Gd0.2Dy0.2)TaO4 ((5RE0.2)TaO4) have been successfully fabricated. The possibility of formation of (5RE0.2)TaO4 was verified via first-principles calculations. In addition, the phase structure, ferroelastic toughening mechanism, thermophysical, and mechanical properties were systematically investigated. The (5RE0.2)TaO4 ceramics have lower phonon thermal conductivity (1.2–2.6 W·m–1·K–1) in the entire temperature range than that of RETaO4 and YSZ. (5RE0.2)TaO4 has a higher fracture toughness and lower brittleness index than YSZ. The thermal expansion coefficients of (5RE0.2)TaO4 are as high as 10.3 × 10-6 K–1 at 1200°C and Young's modulus is 66–189 GPa, and thus, (5RE0.2)TaO4 possesses great potential for application in thermal barrier coatings (TBCs). 相似文献
27.
The fashionable Parr–Pearson (PP) atoms-in-molecule/bonding (AIM/AIB) approach for determining the exchanged charge necessary for acquiring an equalized electronegativity within a chemical bond is refined and generalized here by introducing the concepts of chemical power within the chemical orthogonal space (COS) in terms of electronegativity and chemical hardness. Electronegativity and chemical hardness are conceptually orthogonal, since there are opposite tendencies in bonding, i.e., reactivity vs. stability or the HOMO-LUMO middy level vs. the HOMO-LUMO interval (gap). Thus, atoms-in-molecule/bond electronegativity and chemical hardness are provided for in orthogonal space (COS), along with a generalized analytical expression of the exchanged electrons in bonding. Moreover, the present formalism surpasses the earlier Parr–Pearson limitation to the context of hetero-bonding molecules so as to also include the important case of covalent homo-bonding. The connections of the present COS analysis with PP formalism is analytically revealed, while a numerical illustration regarding the patterning and fragmentation of chemical benchmarking bondings is also presented and fundamental open questions are critically discussed. 相似文献
28.
This paper discusses the capability of Guo et al.'s (2021) equations to determine the discharge of radial gates under submerged flow conditions. It was concluded that Guo et al.'s (2021) equations are associated with error reduction compared to the Incomplete Self-Similarity (ISS) theory and the calibration method. However, it does not have a significant advantage over Energy-Momentum (E-M) approach. Employing E-M principles, new equations were proposed to determine the discharge of radial gates, which has some advantages compared to Guo et al. (2021), such as (1) error reduction under partially and fully submerged flow conditions, (2) least dependence on the empirical constants, (3) uniformity of form over the entire submerged condition, and (4) no need to classify the submerged flow. Field calibration showed that the proposed equations in the present study for a single gate predict the discharge of parallel radial gates with a mean absolute error of less than 4.5% subject to the submerged operation of all open gates. 相似文献
29.
Housei Akazawa 《Ceramics International》2021,47(3):3292-3298
Undoped and Er3+-doped Bi2O3 thin films were sputter-deposited on Si(100) substrates. Sufficiently oxidized Bi2O3 films with refractive indices between 2.17?2.23 were obtained at a wavelength of 633 nm; these values are comparable to those of bulk Bi2O3 crystals. While the film composition was stable for deposition temperatures between room temperature (RT) and 450 °C, the refractive index steeply decreased above 450 °C and reached 1.4 at 600 °C. The lowering of the optical transmittance spectra indicated aggregation of metallic Bi and darkening of the film. All films exhibited X-ray diffraction patterns of α-Bi2O3. The direct and indirect bandgap energies derived from the Tauc plots were 3.4–3.7 eV and 1.9–2.5 eV, respectively, depending on the O2 flow rate and deposition temperature. Upon excitation of Er3+-doped Bi2O3 films at 532 nm, Er3+ emissions peaking at 1537 and 1541 nm appeared, and the photoluminescence spectra included fine structures reflecting crystal-field splitting. Resonant excitation of Er3+ 4f levels and indirect excitation via the defect levels of Bi2O3 followed by energy transfer to Er3+ contributed to the emission. The films deposited at RT with Er concentrations of 2 at.% had the emission intensity of Er3+, but concentration quenching strongly suppressed the Er3+ emission because the doped Er3+ ions stayed inside the Bi2O3 crystals. At deposition temperatures above 400 °C, the concentration quenching was mitigated possibly because out-diffusion of Er3+ ions reduced the effective number of Er3+ ions in the Bi2O3 crystalline domains. 相似文献
30.
The Space-Time Image Velocimetry (STIV) is a time-averaged velocity measurement method, which takes river surface images as the analysis object, and detects the Main Orientation of Texture (MOT) in a generated Space-Time Image (STI) to obtain one-dimensional velocities on the water surface. The STIV has great potential in real-time monitoring of river flow owing to its high spatial resolution and low time complexity. However, the generated STI contains a lot of noise and interference texture, which is inevitable in practical applications. The practicality of the STIV is severely limited by the low-quality STI. To solve this problem, a denoising method based on the filtering technology is proposed and combined with different texture detection algorithms in this paper. The accuracy of this method is verified through a comparative field experiment with an impellor-style current meter. The experimental results show: (1) By using this new denoising method, the robustness and accuracy of the STIV are significantly improved no matter what kind of texture detection algorithm is adopted; (2) Among all the texture detection algorithms, the FFT-based STIV combined with the new denoising method performs best. The relative errors of the surface velocities are controlled within 6%, and the relative errors of the discharges are controlled within ±4%. 相似文献