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排序方式: 共有450条查询结果,搜索用时 15 毫秒
441.
442.
Organic protective coatings are widely used in corrosion control. However, environmental standards establish that the volatile organic compounds either must be removed or controlled at the lowest possible levels. The carcinogenic environmental impact of volatile organic compounds has led to the substitution of solvent‐borne coatings by water‐borne coating systems. Among recently developed water‐borne coatings, epoxy‐ and acrylic‐based coatings have a special significance over other reported water‐borne systems. Keeping in mind, the importance of water‐borne coatings in the present work, we report the synthesis of water‐borne epoxy–acrylate (EpAc) and melamine–formaldehyde (MF) as well as formulation of their anticorrosive coatings. The structural elucidation of MF‐cured EpAc was carried out by FTIR, 1H NMR, and 13C NMR spectroscopic techniques. The coatings of EpAc‐MF were applied on mild steel strips and were evaluated for physicochemical, physicomechanical characterization, and the anticorrosive performance under different environmental conditions. The present coating system EpAc coatings exhibited superior performance as compared to the reported water‐borne epoxy–acrylatecoatings. The presence of melamine–formaldehyde in the resin increases the scratch hardness, impact resistance, alkali resistance, and thermal stability of these coatings. EpAc‐MF‐1 was found to cure at ambient temperature and exhibit good physicomechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   
443.
On February 9 2010, the landslide dam formed in the Kashmir earthquake that occurred on Oct 8 2005 at Hattian Bala in Pakistan was breached after incessant rains. The authors had been involved in a research project to monitor the long-lasting change of the landslide mass at regular 6 monthly intervals since June 2008, and they noticed that air-exposed pieces of sandstones and mudstones of the landslide mass had disintegrated and crumbled due to slaking that dated back to the breach. The change in the landslide mass shape observed between June 2008 and November 2009, did not seem so significant except for a 300 m-long gulley that appeared all of a sudden at the toe of the mass during winter time from 2008 to 2009. Displacements from GPS-measurements conducted in June and November 2009 showed that the crest part subsided by about 10 cm while the toe part heaved slightly up where the overflowed water fell into the eroded gully. A field survey was conducted over the breached landslide dam in April 2010, two months after the breaching event. A severely eroded breach channel was observed along the spillway, which was excavated immediately after the formation of the dam. Given the chronological change in precipitation of the catchment area of Hattian Bala obtained from the TRMM (Tropical Rainfall Measuring Mission) satellite data, the dam is considered to have been breached due to the overtopping of water over the landslide mass of slakable nature. The slakable nature of the material is discussed through both standard slaking tests and advanced unconventional direct shear tests on prepared specimens. Significant creep deformation and a reduction in their peak strength were observed as the slaking developed in the specimens, suggesting that the slakable nature of the mudstones might have been responsible for the breach of the landslide dam.  相似文献   
444.
P-nitrophenol degradation by activated sludge attached on nonwovens   总被引:6,自引:0,他引:6  
Bhatti ZI  Toda H  Furukawa K 《Water research》2002,36(5):1135-1142
p-Nitrophenol (PNP) is a toxic compound that enters the environment during manufacturing and processing of a variety of industrial products. This study demonstrates the use of inexpensive and durable nonwovens as a biomass retainer for the biological degradation of p-nitrophenol. An essential aspect of p-nitrophenol degradation was the cultivation of p-nitrophenol degrading biomass prior to its attachment on the nonwovens. Results of continuous flow experiments demonstrated that using the nonwovens could attain consistent high-rate p-nitrophenol degradation. 500 mg-PNP/L was completely degraded at a hydraulic retention time of 11 h. Specific and volumetric p-nitrophenol loading rates were determined to be 165 mg-PNP/g-MLSS/d and 1.6 g-PNP/L/d, respectively. Nitrite released from p-nitrophenol breakdown was not completely nitrified to nitrate. Characteristics of p-nitrophenol degrading sludge were also investigated.  相似文献   
445.
Unknown cyber-attack detection in network traffic streams is challenging but crucial to ensure network security. It is observed that new security threats occur on a daily basis and make cyberspace vulnerable. In the literature, machine learning and deep learning-based network intrusion detection systems have gained a lot of success but still face many challenges in detecting new security threats and unknown cyber-attacks in real-time. Additionally, high false alarm rates and real-time detection in constantly evolving high-dimensional network data streams are open issues for the research community. To address this issue, a DL-based solution is developed to detect real-time network anomalies in streaming data with high detection accuracy, precision, recall and low false negative and positive scenarios. The proposed novel algorithm, AE-Integrated, is developed and evaluated on the latest CICIDS-2017 dataset. The AE-Integrated is updated with the newest network traffic data stream by the human administrator after a certain period to maintain its prediction accuracy for future inference. The simulation study is conducted with the Apache Kafka and Slack API to get real-time anomaly alerts. Finally, we compared the result with recent state-of-the-art research to evaluate the significance of the proposed algorithm. It is concluded that combining multiple lightweight autoencoders into a single large architecture provides optimal results. The accuracy, recall, and AUC of AE-Integrated obtained are 99.54%, 99.53%, and 0.998, respectively.  相似文献   
446.
The repeated use of cooking oils and ghee for the deep frying of food materials may affect their nutritional quality. The present study evaluated the effect of repeated frying on the physicochemical characteristics and antiradical potential of canola oil and ghee. The oil and ghee were used for frying of fish and chicken for 2, 4, 6, 8, and 10 frying cycles followed by the analysis of physicochemical, oxidative stress, and antiradical parameters. Regression analysis of the data showed a frying cycle-dependent significant linear increase in saponification (R2 = 0.9507–0.9748), peroxide and acid values (R2 = 0.956–0.9915), and malondialdehyde (MDA) production (R2 = 0.9058–0.9557) of canola oil and ghee subjected to fish and chicken frying but exponential increase in saponification value (R2 = 0.9778) and MDA production (R2 = 0.7407) of canola oil and ghee used for fish frying. The increase in the number of frying cycles linearly decreased the iodine value (R2 = 0.9781–0.9924), and 1, 1-diphenyl-2-picrylhydrazyl, hydroxyl, and 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging potential (R2 = 0.9089–0.9979) of canola oil and ghee. Repeated frying in cooking oil and ghee increases oxidative stress and decreases their physicochemical and antioxidant qualities. Canola oil was comparatively more oxidative resistant than canola ghee. The regression equations derived from regression analysis will guide researchers to conduct similar types of univariate studies.  相似文献   
447.
This paper develops a novel probabilistic framework for stochastic nonlinear and uncertain control problems. The proposed framework exploits the Kullback–Leibler divergence to measure the divergence between the distribution of the closed-loop behavior of a dynamical system and a predefined ideal distribution. To facilitate the derivation of the analytic solution of the randomized controllers for nonlinear systems, transformation methods are applied such that the dynamics of the controlled system becomes affine in the state and control input. Additionally, knowledge of uncertainty is taken into consideration in the derivation of the randomized controller. The derived analytic solution of the randomized controller is shown to be obtained from a generalized state-dependent Riccati solution that takes into consideration the state- and control-dependent functional uncertainty of the controlled system. The proposed framework is demonstrated on an inverted pendulum on a cart problem, and the results are obtained.  相似文献   
448.
The substitution of biolubricant for mineral cutting fluids in aerospace material grinding is an inevitable development direction, under the requirements of the worldwide carbon emission strategy. However, serious tool wear and workpiece damage in difficult-to-machine material grinding challenges the availability of using biolubricants via minimum quantity lubrication. The primary cause for this condition is the unknown and complex influencing mechanisms of the biolubricant physicochemical properties on grindability. In this review, a comparative assessment of grindability is performed using titanium alloy, nickel-based alloy, and high-strength steel. Firstly, this work considers the physicochemical properties as the main factors, and the antifriction and heat dissipation behaviours of biolubricant in a high temperature and pressure interface are comprehensively analysed. Secondly, the comparative assessment of force, temperature, wheel wear and workpiece surface for titanium alloy, nickel-based alloy, and high-strength steel confirms that biolubricant is a potential replacement of traditional cutting fluids because of its improved lubrication and cooling performance. High-viscosity biolubricant and nano-enhancers with high thermal conductivity are recommended for titanium alloy to solve the burn puzzle of the workpiece. Biolubricant with high viscosity and high fatty acid saturation characteristics should be used to overcome the bottleneck of wheel wear and nickel-based alloy surface burn. The nano-enhancers with high hardness and spherical characteristics are better choices. Furthermore, a different option is available for high-strength steel grinding, which needs low-viscosity biolubricant to address the debris breaking difficulty and wheel clogging. Finally, the current challenges and potential methods are proposed to promote the application of biolubricant.  相似文献   
449.
Journal of Mechanical Science and Technology - In this study, the analysis is carried out to optimize in-gate position and size of riser for casting mold. The baseline size of riser for the casting...  相似文献   
450.
Erucic acid is a single unsaturated fatty acid that falls under the omega-9 fatty acid family. It was suggested to treat Wistar rats with lipopolysaccharide (LPS)-induced memory impairment and minimize cognitive impairment. A total of 30 animals were randomized: group I was normally treated group, group II was administered with LPS, group III was treated with LPS along with erucic acid at the dose of 10 mg kg–1 p.o.–1, group IV was treated with LPS along with erucic acid at 20 mg kg–1 p.o.–1 and group V was the erucic acid per se group provided at the dose of 20 mg kg–1 p.o.–1 per se. Behavioral tests were evaluated by using the Morris water maze and Y-maze. Biochemical analysis including acetylcholine esterase (AChE), choline acetyltransferase (ChAT), glutathione (GSH), catalase activity (CAT), superoxide dismutase (SOD), and nitric oxide (NO) along with proinflammatory mediators tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), caspase 3, and neuroinflammatory biomarker (nuclear factor kappa B-NF-κB) were measured. Erucic acid produced substantial behavioral improvement in the Y-maze test, including spontaneous alterations and reduced latency time during acquisition, and a longer duration of time in the consolidation phase undergoing the MWM test. Furthermore, erucic acid improved the AChE, proinflammatory markers, and oxidative stress as well as restoring endogenous antioxidant levels, ChAT, caspase 3, and NF-κB levels. Erucic acid may be a therapeutic component for conditions related to memory disorders such as memory impairment, enhances memory functioning, and protects against neuronal damage.  相似文献   
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