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Study and Improvement of Stability of Generator-based Distributed Generation units Inpresence of Large Nonlinear Loads

Afzali, Kiana | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51047 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Mokhtari, Hossein
  7. Abstract:
  8. Hyderogels are hydrophilic polymers with three dimensional network structure, due to their high water absoption, their application to life and industry is increasing from day to day, such as tissue engineering, actuators and sensors, drug delivery and therapeutic treatment. In this project, it has been attempted to produce polyacrylamide/alginate double network hydrogels with the use of graphene oxide nanosheets to indicate that it is possible to combine toughness and self-healing in a hydrogel with the opposite nature of each other. To evaluate mechanical properties, uniaxial tensile test and loading-unloading test were used. The results indicate that increase the weight ratio of acrylamide monomer to alginate from a ratio of 2:1 to 3:1, would increase the tear energy from 625 J/m2 to 2409.7 J/m2 and self-healing decreases by 27.7%, but the use of grapheme oxide nanosheets results in an increase in tear energy from 2660 J/m2 to 3022.6 J/m2 and self-healing increases by 21.6%. A swelling test was used to examine the swelling behavior. The results show that increasing the weight ratio of acrylamide monomer to alginate, the water absorption kinetic follows exponential association model, and the water content also varies from about 10 to 25, and the addition of graphene oxide nanosheets leads to a change in the water absorption kinetic from exponential association to Peleg and the water content varies from 4 to 12. To investigate the rheological behavior, stress relaxation test was used. The results indicate that by increasing the weight ratio of acrylamide monomer to alginate, the elastic contribution of hydrogel and the stress relaxation amount is reduced and by the addition of graphene oxide nanosheets to the double network hydrogel, the elastic contribution and the stress relaxation amount is increased. Finally, by structural analysis of three samples of synthesized hydrogels with a weight ratio of 3: 1, it is shown that the structure of the hydrogel in the nanocomposite one has changed from that of the double network and has transformed from the spongy structure to the lamellar one. The reason for all these events is the presence of physical crosslinks between polyacrylamide chains and graphene oxide nanosheets
  9. Keywords:
  10. Interharmonic ; Dispersed Generation ; Synchronous Generator ; Six Phase Motor ; Islanded Microgrid ; Generator-based Distributed Generation ; Variable Speed Drive (VSD) ; Pitching Oscillation

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