In this study, we have studied the effects of polyfunctional monomers (PFMs) on physical properties of ethylene vinyl acetate
(EVA) copolymer crosslinked with electron beam (EB) or peroxides. The PFMs used were triallylcyanurate, triallylisocyanurate,
trimethylolpropane trimethacrylate, zinc diacrylate, and ethylene glycol dimethacrylate. Using PFMs has led to (1) optimum
cure time t90 decrease from 19′25″ to 17′30″–18′45″, (2) scorch time increase from 2′ to maximum 3′45″, (3) increasing the crosslink density
of peroxide or EB-cured systems by increasing the efficiency of productive radical reactions. The most efficient PFM for EVA
copolymer blends has been triallylisocyanurate. Tensile strength and tear strength of samples crosslinked with EB for all
irradiation doses are significantly better than those obtained for samples crosslinked with peroxides (differences up to 190%).
The results show that EB irradiation gave the best results 相似文献
Ceramic capacitors are an indispensable component in electronic circuits, since they are used in various applications such as timing, filtering, and decoupling. These capacitors are doped with REEs that improve their operating life and electrical properties. In this paper, the economics of rare earth elements (REEs) are reviewed in light of their importance in ceramic capacitors. The developing rare earth element supply and demand crisis that can negatively impact the ceramic capacitor industry and, hence, the global economy, is explained. The cause of this crisis and the response of the world are also discussed. 相似文献
Using specific M-cholinoblockers the response of rat pulmonary and mediastinal pleural mast cells to acetylcholine was studied. Acetylcholine was established to cause their massive degranulation which is prevented by preliminary administration of atropin or bromide ipratropium. Electric current stimulation of the vagal nerve caused similar reaction in mast cells. The transection of vagal nerve inferior to ganglion nodosum augmented the synthesis of specific granules in mast cells, although blocked their cytosis. Acetyl cholinestherase reaction demonstrated axons in pleura, while electron microscopic studies revealed terminals containing cholinergic synaptic vesicles on mast cells. A conclusion was made concerning functional interaction between mast cells and vagal nerve axons. 相似文献
AIM: Assessment of NO-synthase (NOS) activity in bronchial asthma (BA) basing on cytochemical identification and quantitation of NADPN-diaphorase. MATERIALS AND METHODS: Operative samples from 12 BA patients and biopsies from 8 patients free of bronchial inflammation or obstruction. Experimental data on control and BA rat males injected either with NOS agonist acetyl choline (AC) or beta-2-agonist fenoterol (F). RESULTS: A direct relationship was found between BA severity and activity of NADPN-diaphorase resultant from activation of inducible NOS (iNOS) mediating constrictive effect via different cellular and humoral mechanisms. AC treatment caused bronchial relaxation and severe constriction in control and BA rats, respectively, though NADPN-diaphorase activity was enhanced in both groups. Introduction of F brought about bronchial relaxation in both groups. However, there were some cases of constriction in the bronchi with impaired epithelium and high baseline iNOS activity. CONCLUSION: In intact bronchial epithelium, administration of cholino- and adrenoreceptors agonists induced bronchial myocyte relaxation due to activation of constitutive NOS. In impaired bronchial epithelium, AC stimulates iNOS induction provoking severe constriction of small bronchi. 相似文献
This paper presents measurement results of the world wide first successful certification the electrical properties of a wind turbine, solely based upon measurements obtained at a system test bench with HiL-System and grid emulator. For all certification relevant tests the results are compared to field measurements. The impact of the real-time models in the HiL-System as well as the converter-based grid emulator are discussed in this paper. For full converter wind turbine, different requirements for the model depth could be determined depending on the tests. Nevertheless, higher-quality models that reflect the plant behaviour better are recommended to reduce uncertainties within the certification process. This paper also shows that especially for grid failure events grid emulators require real-time impedance control, in order to emulate grid failures properly. Based on these findings, recommendations for the requirements on test bench components are formulated in this paper, in order to contribute to new certification guidelines. Overall, we conclude that based on the experiences made at two different system test benches, the vast majority of certification measurements can be carried out without limitation at such system test benches.
Wind turbines are a major source of renewable energy. Load monitoring is considered to improve reliability of the systems and to reduce the cost of operation. We propose a load monitoring system which consists of inertial measurement units. These track the movement of rotor blade, hub and tower top. In addition, wind turbine states, e.g. yaw angle, pitch angle and rotation speed, are recorded. By solving a navigation algorithm with a Kalman Filter approach, the raw sensor data is combined with an error model to reduce the tracking error. In total, five inertial measurement units are installed on the research wind energy converter AD 8–180 on the test site in Bremerhaven. Results show that tracking the blade movement in full operation is possible and that loads can be estimated with a model-based approach. In comparison to simulations, the blade deflections can be approximated by an aeroelastic model. The presented approach can be used as basis for comprehensive load monitoring and observer system with additional increase of system robustness by measurement redundancy.