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41.
Application of Structured and Directional Residuals for Fault Detection and Isolation on Permanent‐Magnet DC Motor with Amplifier 下载免费PDF全文
Sanja Antic Zeljko Djurovic Goran Kvascev 《Quality and Reliability Engineering International》2016,32(7):2601-2621
Sensors and actuators are physical components often subjected to non‐permissible or unexpected deviations from nominal operating conditions. This paper discusses the application of additive fault detection and isolation (FDI) methods developed for linear and stationary systems on a nonlinear non‐stationary system consisting of an electronic amplifier with a DC motor. A temperature‐dependent viscous friction coefficient, as well as the non‐linearity induced by dry friction, makes the system nonlinear. Residuals were designed using two fundamental residual‐enhancement approaches: synthesis of structured residuals and synthesis of directional residuals. A comparative analysis of the results was performed applying four different techniques for residual transformation synthesis. The paper proposes suitable filtering and translation of the structured and directional residuals that enhance FDI, performance. A limiting factor in the application of directional residuals, relating to the number of different faults, which may have independent directions during FDI, is illustrated. The entire procedure is demonstrated on a simple model of a permanent‐magnet DC motor with a suitable amplifier. This laboratory system is often encountered in electrical engineering laboratories, and accordingly, the results can be used as useful educational material for student training in FDI. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
42.
Teodor M. Atanacković Sanja Konjik Stevan Pilipović Dušan Zorica 《Mechanics of Time-Dependent Materials》2016,20(2):175-195
We introduce complex order fractional derivatives in models that describe viscoelastic materials. This cannot be carried out unrestrictedly, and therefore we derive, for the first time, real valued compatibility constraints, as well as physical constraints that lead to acceptable models. As a result, we introduce a new form of complex order fractional derivative. Also, we consider a fractional differential equation with complex derivatives, and study its solvability. Results obtained for stress relaxation and creep are illustrated by several numerical examples. 相似文献
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44.
Liridona Useini Marija Mojić Dr. Markus Laube Dr. Peter Lönnecke Dr. Sanja Mijatović Dr. Danijela Maksimović-Ivanić Prof. Dr. Jens Pietzsch Prof. Dr. Dr. h.c. mult. Evamarie Hey-Hawkins 《ChemMedChem》2023,18(5):e202200583
Fenoprofen is a widely used nonsteroidal anti-inflammatory drug (NSAID) against rheumatoid arthritis, degenerative joint disease, ankylosing spondylitis and gout. Like other NSAIDs, fenoprofen inhibits the synthesis of prostaglandins by blocking both cyclooxygenase (COX) isoforms, COX-1 the “house-keeping” enzyme and COX-2 the induced isoform from pathological stimuli. Unselective inhibition of both COX isoforms results in many side effects, but off-target effects have also been reported. The steric modifications of the drugs could afford the desired COX-2 selectivity. Furthermore, NSAIDs have shown promising cytotoxic properties. The structural modification of fenoprofen using bulky dicarba-closo-dodecaborane(12) (carborane) clusters and the biological evaluation of the carborane analogues for COX inhibition and antitumor potential showed that the carborane analogues exhibit stronger antitumor potential compared to their respective aryl-based compounds. 相似文献
45.
Ronald E. Unger Sanja Stojanovic Laura Besch Said Alkildani Romina Schrder Ole Jung Caroline Bogram Oliver Grke Stevo Najman Wolfgang Tremel Mike Barbeck 《International journal of molecular sciences》2022,23(3)
Injectable bone substitutes (IBS) are increasingly being used in the fields of orthopedics and maxillofacial/oral surgery. The rheological properties of IBS allow for proper and less invasive filling of bony defects. Vaterite is the most unstable crystalline polymorph of calcium carbonate and is known to be able to transform into hydroxyapatite upon contact with an organic fluid (e.g., interstitial body fluid). Two different concentrations of hydrogels based on poly(ethylene glycol)-acetal-dimethacrylat (PEG-a-DMA), i.e., 8% (w/v) (VH-A) or 10% (w/v) (VH-B), were combined with vaterite nanoparticles and implanted in subcutaneous pockets of BALB/c mice for 15 and 30 days. Explants were prepared for histochemical staining and immunohistochemical detection methods to determine macrophage polarization, and energy-dispersive X-ray analysis (EDX) to analyze elemental composition was used for the analysis. The histopathological analysis revealed a comparable moderate tissue reaction to the hydrogels mainly involving macrophages. Moreover, the hydrogels underwent a slow cellular infiltration, revealing a different degradation behavior compared to other IBS. The immunohistochemical detection showed that M1 macrophages were mainly found at the material surfaces being involved in the cell-mediated degradation and tissue integration, while M2 macrophages were predominantly found within the reactive connective tissue. Furthermore, the histomorphometrical analysis revealed balanced numbers of pro- and anti-inflammatory macrophages, demonstrating that both hydrogels are favorable materials for bone tissue regeneration. Finally, the EDX analysis showed a stepwise transformation of the vaterite particle into hydroxyapatite. Overall, the results of the present study demonstrate that hydrogels including nano-vaterite particles are biocompatible and suitable for bone tissue regeneration applications. 相似文献
46.
Nader Mohamed Jameela Al-Jaroodi Imad Jawhar Sanja Lazarova-Molnar 《Journal of Intelligent and Robotic Systems》2014,74(1-2):309-321
For a while, Unmanned Arial Vehicles (UAVs) use was limited to military applications, however recently UAVs are also used for a wide range of civilian applications. Some of these UAV applications may involve multiple UAVs that must cooperate to achieve a common goal. This kind of applications is termed collaborative UAV applications. This paper investigates the collaborative aspects and challenges of multiple UAV systems. One of the main issues for multiple UAV systems is developing an effective framework to enable the development of software systems for collaborative UAV operations. One possible approach is to rely on service-oriented computing and service-oriented middleware technologies to simplify the development and operations of such applications. This paper discusses how the service-oriented middleware approach can help resolve some of the challenges of developing collaborative UAVs. The paper also proposes a service-oriented middleware architecture that can satisfy the development and operations of such applications. 相似文献
47.
A series of selected 4-methylcoumarins (4-methyl-2H-1-benzopyran-2-ones) were synthesised and tested for radical-scavenging ability using the stable 1,1-diphenyl-2-picrylhydrazyl radical, and for reducing power ability with a test based on the reduction of ferric to ferrous cation. All studied compounds showed activity comparable to Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), an already known antioxidant, which is used as standard in most of the testing methods. Observations from the study were made with regard to structural features that regulated the behaviour of the compounds. The antioxidant activity of some 4-methylcoumarin representatives is presented here for the first time and extends our knowledge of the range of valuable biological activities and possible roles in therapy and for food preservation associated with this group of compounds. 相似文献
48.
Vladimir Stevanovic Stojan Cucuz Waldemar Carl-Meissner Blazenka Maslovaric Sanja Prica 《International Journal of Heat and Mass Transfer》2012,55(13-14):3335-3343
Evaporators in automotive air conditioning are designed as compact heat exchangers with the aim to cool outside air for the widest possible range of weather conditions. Under low operating loads a non-uniformity of the refrigerant liquid and gas phase distribution from the evaporator headers towards the evaporating channels leads to a decrease of the evaporator efficiency and a temperature stratification in the exit stream of cooled air. This malfunction is investigated by numerical simulations and analyses with the Computational Multi-Fluid Dynamic code. The applied numerical approach is validated for available experimental conditions. In order to eliminate the air exit temperature stratification, numerical experiments are performed with design changes of the evaporator header and the effectiveness of applied measures is demonstrated. 相似文献
49.
Stela Jokić Marina Cvjetko Đurđica Božić Sanja Fabek Nina Toth Jasna Vorkapić‐Furač Ivana Radojčić Redovniković 《International Journal of Food Science & Technology》2012,47(12):2613-2619
The effect of independent variables of microwave‐assisted extraction (MAE), extraction temperature (50–90 °C), microwave power (100–200 W), solvent concentration (methanol/water, 50–90%, v/v) and extraction time (1–27 min) on total phenolics and flavonoids contents as well as antioxidant activity of broccoli extracts was investigated. Response surface methodology was successfully applied for optimisation and the high correlation of the mathematical model indicated that a quadratic polynomial model could be used for optimisation of investigated responses. Considering the maximum amount of extracted total phenolics, total flavonoids and antioxidant activity expressed as ORAC value, the optimal conditions for all three investigated responses were obtained (temperature ?71.11 °C; microwave power ?167.03 W; solvent concentration ?75.95%; and extraction time 16.34 min), which is in agreement with optimal conditions obtained for each investigated responses. The development of simultaneously MAE methods for total phenolics, total flavonoids and antioxidant activity of broccoli extracts might simplify assessment of broccoli as valuables source of antioxidants. 相似文献
50.
Continuing our research on oxidation reactions of 4-methylcoumarins (4-methyl-2H-1-benzopyran-2-ones), this study presents evaluation of the antioxidant activity of 23 4-methylcoumarin derivatives, using different spectrophotometric and spectrofluorimetric radical testing methods. All studied compounds showed activity comparable to Trolox, an already known antioxidant, which is used as a standard in most testing methods. Observations from the study were made with regard to structural features that regulated the behaviour of the compounds. This paper extends our knowledge of the range of valuable biological activities and possible roles in medicinal therapy associated with this group of compounds. 相似文献