210 research outputs found
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Optimization of staged rankine energy conversion cycles for high efficiency
Get PDFBecause of the fuel crisis and problems associated with thermal
pollution there is new impetus and urgency for developing more
efficient energy conversion systems for power generation. A preliminary
analysis was undertaken to determine the potential of staged
Rankine cycle systems for substantially higher efficiency. It was
necessary to optimize the cycles to determine maximum potential
efficiency, and the Sequential Unconstrained Minimization Technique
of nonlinear programming was implemented on the Oregon State University
CDC 3300 computer for this purpose. Binary, ternary, and quaternary
Rankine cycle configurations were optimized for maximum efficiency
under a set of realistic constraints. Liquid metal working fluids
were used for the higher temperature stages with water for the low
temperature stage fluid.
Maximum efficiencies are presented for the best cycle configurations
with peak temperatures from 900°F to 3000°F. Sensitivity
of the results to certain critical assumptions is also included. The
potential efficiency gains at current peak cycle temperatures are small, but, if high temperature expanders such as high temperature
turbines, graphite helical rotor expanders, or MHD vapor expanders
prove to be feasible, staged Rankine cycles can clearly provide high
efficiencies with much lower temperature requirements than magnetohydrodynamic
Brayton systems.
In order to determine ultimate potential of the staged cycles,
conventional Rankine cycle improvements were considered for each
stage also. Only extraction/regeneration was found to give any
significant improvement and results are presented for a binary configuration
with one to five extractions on each stage. Organic working
fluids were considered as a replacement for mercury, and ammonia
was considered as a low temperature stage working fluid for a stage
below the steam cycle. Neither organic fluids nor ammonia proved to
have any outstanding advantages for use in staged cycles. Staged
cycles with a metal working fluid topping a steam cycle are probably
best overall
Paper Session II-A - SIRTF: The Fourth Great Observatory
Get PDFThe Space Infrared Telescope Facility (SIRTF), the fourth of the Great Observatories, will look through a new window on the universe. Using SIRTF, the astronomical community will be able to explore the infrared universe with a depth and precision complementary to that achieved by NASA’s other Great Observatories-the Hubble Space Telescope (HST), the Advanced X-ray Astrophysics Facility (AXAF), and the Compton Gamma Ray Observatory (GRO). SIRTF will achieve unprecedented infrared sensitivity by fully utilizing a new generation of infrared detector arrays. The new detectors, combined with an 85-cm cryogenic telescope, will allow SIRTF to provide scientific capabilities so impressive that SIRTF was designated the highest priority major new mission for all US astronomy in the 1990s. This paper will provide a review of the SIRTF program—the science, mission design, facility, and the instruments. Emphasis will be placed on those features of the program which will allow us to realize the great scientific potential of the Observatory in a resource-constrained environment
ASK Magazine; No. 21
Get PDFTHIS ISSUE FEATURES A VISUAL DEPICTION OF THE ACADEMY of Program and Project Leadership (APPL). I imagine a variety of initial reactions to the drawing. One might be, "What is a cartoon doing in a magazine about project management?" Or perhaps, "Wow, nice colors-and fun." Another may be to closely search the image for signs, symbols and meaning. Still another, to read a new level of innovation and creativity into the picture. Undoubtedly, some readers will raise questions about the cost. Of course, any reaction is a sign of engagement. The stronger, the more energized the emotional and cognitive processing, the better. It is a sign of attention and interaction. For I've heard it said, "You only need to worry if they don t care one way or the other." So what is the point of the picture? To stimulate interest, raise questions, promote discussion, and maybe raise a smile.. .That, at least, was my initial reaction when I was introduced to the work of Nancy Hegedus, who helps to create these drawings for Root Learning Inc. At the NASA PM Conference, I was first shown the work Nancy had been doing with the help of Goddard s Knowledge Management Architect, Dr. Ed Rogers. I was immediately drawn into the power of visualization as a tool for more effective learning, communicating, and conveying complex knowledge concepts. We need new tools in today s world, where information and data overwhelms by sheer volume. There are articles, pamphlets, communications, and white papers-all aiming to convince and influence. Reactions to these tend to be either avoidance or mind-numbing, heavy-eyed consent; the message never registers or enters the soul. That s one of the reasons that APPL s Knowledge Sharing Initiative (KSI) has turned to storytelling as a memorable way of transfer- ring knowledge, inspiring imitation of best practices, and spurring reflection. ASK Magazine s recent fourth birthday marks an important milestone in APPL s continuing quest to provide ongoing support to project managers and to promote mission success. And similar to storytelling, the power of visualization is receiving increasing attention in recent years as a way to stimulate engagement. Pictures and visual graphs are viewed as one of the most effective ways for displaying, describing, and generating discussion about quantitative and technically complex information. Prototypes, models, and simulations are considered essential for stimulating innovation through open and engaging discussions. There has also been extensive writing on the use of visual graphics, pictures, and cartoons to facilitate memory, creativity, openness, attention-and even well-being. For many of these reasons, I am excited to have a colorful visual depiction of the APPL world included in ASK. Without the addition of text or slides, the intent is to invite people into the world of the APPL mission-as well as its products, services, customers, and partners- in a fun and engaging manner. As project leaders strive to find ways to encourage engagement, learning, and transmission of knowledge, traditional technologies are proving to be as valuable as modern technologies. (But for those who want more information in the form of texts and slide presentations, we certainly have an abundance of those as well.
Wireworms in Conservation Reserve: An Evaluation of Risk Using GIS Technology and Discovering Effective Sampling Techniques
Get PDFThe mission of the Conservation Reserve Program (CRP), introduced in 1985, is to reduce soil erosion and increase wildlife habitat by planting native cool-season grasses on highly erodible land. After 10 years of fallow conditions, farmers can expect any number of problems when returning this land to crop production. One probable result will be the occurrence of soil-insect pests, primarily wireworms (Coleoptera: Elateridae )
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