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Shih C.,University of Connecticut | Han S.,Southeast University
57th ISA Power Industry Division Symposium 2014, POWID 2014 - Power Generation: Instrumentation and Control Solutions for Today's Industry Challenges | Year: 2014

Evaluating wind farm effective loading carrying capacity (ELCC) is an important task in planning wind power systems. A model based on wind turbine generator was proposed to identify wind farm capacity in the presence loading to grid. When the additional load was added, the additional wind farm capacity will be installed to maintain the same reliability. The wind farm also combines an energy storage device that smooths the power output curve. The smooth power output will contribute to effective loading carrying capacity. Further, optimal installed wind farm capacity that maximizes the effect of the installed wind farm load on the grid, including reliability considerations, will be described in this paper. Copyright © (2014) by International Society of Automation - ISA All rights reserved. Source


Leach M.K.,University of Michigan | Feng Z.-Q.,University of Michigan | Feng Z.-Q.,Southeast University | Tuck S.J.,University of Michigan | And 2 more authors.
Journal of Visualized Experiments | Year: 2010

Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. Electrospinning is a process in which a charged polymer jet is collected on a grounded collector; a rapidly rotating collector results in aligned nanofibers while stationary collectors result in randomly oriented fiber mats. The polymer jet is formed when an applied electrostatic charge overcomes the surface tension of the solution. There is a minimum concentration for a given polymer, termed the critical entanglement concentration, below which a stable jet cannot be achieved and no nanofibers will form - although nanoparticles may be achieved (electrospray). A stable jet has two domains, a streaming segment and a whipping segment. While the whipping jet is usually invisible to the naked eye, the streaming segment is often visible under appropriate lighting conditions. Observing the length, thickness, consistency and movement of the stream is useful to predict the alignment and morphology of the nanofibers being formed. A short, non-uniform, inconsistent, and/or oscillating stream is indicative of a variety of problems, including poor fiber alignment, beading, splattering, and curlicue or wavy patterns. The stream can be optimized by adjusting the composition of the solution and the configuration of the electrospinning apparatus, thus optimizing the alignment and morphology of the fibers being produced. In this protocol, we present a procedure for setting up a basic electrospinning apparatus, empirically approximating the critical entanglement concentration of a polymer solution and optimizing the electrospinning process. In addition, we discuss some common problems and troubleshooting techniques. © 2011 Journal of Visualized Experiments. Source


Patent
Southeast University | Date: 2011-03-02

A new three-dimensional measurement method based on wavelet transform to solve the phase distribution of a fringe pattern accurately and obtain three-dimensional profile information of a measured object from phase distribution. The method includes: projecting a monochrome sinusoidal fringe pattern onto the object; performing wavelet transform for the deformed fringe pattern acquired with CCD line by line, solving the relative phase distribution by detecting the wavelet ridge line, recording the wavelet transform scale factors at the line, and creating a quality map; dividing the relative phase distribution into two parts according to the map, and performing direct-phase unwrapping for the part with better reliability using a scan line based algorithm, and unwrapping the part with lower reliability using a flood algorithm under the guide of the quality map, to obtain the absolute phase distribution of the fringe pattern; obtaining the three dimensional information using a phase-height conversion.


Home > Press > Scientists see the light on microsupercapacitors: Rice University's laser-induced graphene makes simple, powerful energy storage possible Abstract: ice University researchers who pioneered the development of laser-induced graphene have configured their discovery into flexible, solid-state microsupercapacitors that rival the best available for energy storage and delivery. The devices developed in the lab of Rice chemist James Tour are geared toward electronics and apparel. They are the subject of a new paper in the journal Advanced Materials. Microsupercapacitors are not batteries, but inch closer to them as the technology improves. Traditional capacitors store energy and release it quickly (as in a camera flash), unlike common lithium-ion batteries that take a long time to charge and release their energy as needed. Rice's microsupercapacitors charge 50 times faster than batteries, discharge more slowly than traditional capacitors and match commercial supercapacitors for both the amount of energy stored and power delivered. The devices are manufactured by burning electrode patterns with a commercial laser into plastic sheets in room-temperature air, eliminating the complex fabrication conditions that have limited the widespread application of microsupercapacitors. The researchers see a path toward cost-effective, roll-to-roll manufacturing. "It's a pain in the neck to build microsupercapacitors now," Tour said. "They require a lot of lithographic steps. But these we can make in minutes: We burn the patterns, add electrolyte and cover them." Their capacitance of 934 microfarads per square centimeter and energy density of 3.2 milliwatts per cubic centimeter rival commercial lithium thin-film batteries, with a power density two orders of magnitude higher than batteries, the researchers claimed. The devices displayed long life and mechanical stability when repeatedly bent 10,000 times. Their energy density is due to the nature of laser-induced graphene (LIG). Tour and his group discovered last year that heating a commercial polyimide plastic sheet with a laser burned everything but the carbon from the top layer, leaving a form of graphene. But rather than a flat sheet of hexagonal rings of atoms, the laser left a spongy array of graphene flakes attached to the polyimide, with high surface area. The researchers treated their LIG patterns -- interdigitated like folded hands -- with manganese dioxide, ferric oxyhydroxide or polyaniline through electrodeposition and turned the resulting composites into positive and negative electrodes. The composites could then be formed into solid-state microsupercapacitors with no need for current collectors, binders or separators. Tour is convinced the day is coming when supercapacitors replace batteries entirely, as energy storage systems will charge in minutes rather than hours. "We're not quite there yet, but we're getting closer all the time," he said. "In the interim, they're able to supplement batteries with high power. What we have now is as good as some commercial supercapacitors. And they're just plastic." Rice graduate students Lei Li and Jibo Zhang and alumnus Zhiwei Peng are lead authors of the paper. Co-authors are Rice postdoctoral researchers Yongsung Ji, Nam Dong Kim, Gedeng Ruan and Yang Yang and graduate students Yilun Li, Ruquan Ye and Huilong Fei; Caitian Gao, a visiting graduate student at Rice from Lanzhou University, China; and Qifeng Zhong, a visiting graduate student at Rice from Southeast University, Nanjing, China. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of materials science and nanoengineering and of computer science. The Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative and the Chinese Scholarship Council supported the research. About Rice University Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice’s undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance. Follow Rice News and Media Relations via Twitter @RiceUNews For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


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Rice University researchers who pioneered the development of laser-induced graphene have configured their discovery into flexible, solid-state microsupercapacitors that rival the best available for energy storage and delivery. The devices developed in the lab of Rice chemist James Tour are geared toward electronics and apparel. They are the subject of a new paper in the journal Advanced Materials. Microsupercapacitors are not batteries, but inch closer to them as the technology improves. Traditional capacitors store energy and release it quickly (as in a camera flash), unlike common lithium-ion batteries that take a long time to charge and release their energy as needed. Rice’s microsupercapacitors charge 50 times faster than batteries, discharge more slowly than traditional capacitors, and match commercial supercapacitors for both the amount of energy stored and power delivered. The devices are manufactured by burning electrode patterns with a commercial laser into plastic sheets in room-temperature air, eliminating the complex fabrication conditions that have limited the widespread application of microsupercapacitors. The researchers see a path toward cost-effective, roll-to-roll manufacturing. “It’s a pain in the neck to build microsupercapacitors now,” Tour says. “They require a lot of lithographic steps. But these we can make in minutes: We burn the patterns, add electrolyte and cover them.” Their capacitance of 934 microfarads per square centimeter and energy density of 3.2 milliwatts per cubic centimeter rival commercial lithium thin-film batteries, with a power density two orders of magnitude higher than batteries, the researchers claimed. The devices displayed long life and mechanical stability when repeatedly bent 10,000 times. Their energy density is due to the nature of laser-induced graphene (LIG). Tour and his group discovered last year that heating a commercial polyimide plastic sheet with a laser burned everything but the carbon from the top layer, leaving a form of graphene. But rather than a flat sheet of hexagonal rings of atoms, the laser left a spongy array of graphene flakes attached to the polyimide, with high surface area. The researchers treated their LIG patterns — interdigitated like folded hands — with manganese dioxide, ferric oxyhydroxide or polyaniline through electrodeposition and turned the resulting composites into positive and negative electrodes. The composites could then be formed into solid-state microsupercapacitors with no need for current collectors, binders or separators. Tour is convinced the day is coming when supercapacitors replace batteries entirely, as energy storage systems will charge in minutes rather than hours. “We’re not quite there yet, but we’re getting closer all the time,” he says. “In the interim, they’re able to supplement batteries with high power. What we have now is as good as some commercial supercapacitors. And they’re just plastic.” Rice graduate students Lei Li and Jibo Zhang and alumnus Zhiwei Peng are lead authors of the paper. Co-authors are Rice postdoctoral researchers Yongsung Ji, Nam Dong Kim, Gedeng Ruan, and Yang Yang and graduate students Yilun Li, Ruquan Ye, and Huilong Fei; Caitian Gao, a visiting graduate student at Rice from Lanzhou University, China; and Qifeng Zhong, a visiting graduate student at Rice from Southeast University, Nanjing, China. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of materials science and nanoengineering and of computer science. The Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative and the Chinese Scholarship Council supported the research.

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