120 research outputs found
Experimental results from a laboratory-scale molten salt thermocline storage
No full textArt. 080025, 10 S.Single-tank storage presents a valid option for cost reduction in thermal energy storage systems. For low-temperature systems with water as storage medium this concept is widely implemented and tested. For high-temperature systems very limited experimental data are publicly available. To improve this situation a molten salt loop for experimental testing of a single-tank storage prototype was designed and built at Fraunhofer ISE. The storage tank has a volume of 0.4 m3 or a maximum capacity of 72 kWhth. The maximum charging and discharging power is 60 kW, however, a bypass flow control system enables to operate the system also at a very low power. The prototype was designed to withstand temperatures up to 550 °C. A cascaded insulation with embedded heating cables can be used to reduce the effect of heat loss on the storage which is susceptible to edge effects due to its small size. During the first tests the operating temperatures were adapted to the conditions in systems with thermal oil as heat transfer fluid and a smaller temperature difference. A good separation between cold and hot fluid was achieved with temperature gradients of 95 K within 16 cm
Review of \u3ci\u3eMarch of the Columns: A Chronicle of the 1876 Indian War, June 27-September 16, 1876\u3c/i\u3e By James Willert
No full textUnbearable heat, driving thunderstorms, endless marching, and poor rations were daily fare for the soldier on the Plains. Weeks of tedious riding culminated in brief moments of sheer terror when the adversary was finally confronted. March of the Columns provides the day by day exploits, movements, and disappointments of US soldiers in pursuit of Cheyenne and Sioux warriors along the Yellowstone, Tongue, and Powder Rivers. The tale begins two days after the defeat of Custer\u27s Seventh Cavalry and culminates with the end of the summer campaign. Sandwiched between are the numerous anecdotes, tragedies, and travels of Generals George Crook and Alfred Terry, Colonels Nelson Miles and Wesley Merritt, and their troops.
As volume four of a six book series, this extensively researched and well written account will increase the reader\u27s knowledge and appreciation of a small segment of the wars between the Army and the Indians. Volumes one and two in the Custer Trails Series, Benteen\u27s Scout to the Left and Custer\u27s 7th Cavalry Comes to Dakota, both by Roger Darling, were followed by W. Kent King\u27s Massacre. Volume five, Custer and the Cheyenne, by Lewis Kraft, covers the years 1867-68. The final work, James Willert\u27s Little Big Horn Diary, originally published by the author in 1976, has been supplemented and updated to include new information. With the release of March of the Columns, Willert has finally followed up on his effort to tell the story of the 1876 campaign.
Tracing the movements of the various units desperately trying to locate and defeat the victors in the Custer battle, Willert carefully integrates the action on the Plains, on the rivers, and in Washington. He also includes narratives by Indians associated with the battle at Little Big Horn, though these are too brief; other works capture this dimension in greater detail. For the historian or general reader who wants a comprehensive study of Army life on the frontier, however, this book provides significant detail and firsthand accounts capturing the harsh realities of daily life. Extensive quotes by the participants help the reader appreciate the hardships, confusion, and tragedy accompanying military duty. Inadequate communication systems, non-existent transportation networks, and sometimes brutal living conditions were just a few of the problems soldiers encountered. Infrequent fishing and hunting expeditions, spectacular sunsets, and other benefits of this life also come alive through the author\u27s detailed account.
Including the action on the rivers by the steamboats Durfee, Far West, Carroll, and Josephine explains how important the waterways were, but also shows how limiting they could be to an Army marching or riding far upstream or great distances from any water system. Sparse but important guidance from the nation\u27s capital highlights the problems commanders had determining their duties and detailing their responsibilities in dealing with Indian peoples on and off the reservations.
Although printed from camera ready copy, this book is wonderfully illustrated and includes numerous maps, photographs, and drawings that add to its appeal. Anyone interested in the aftermath of the Custer defeat or the lifestyle of the 1870s Army soldier will enjoy this book. For the serious student, March of the Columns provides a wealth of source material in an inviting format
The effect of additives on high temperature water retention and thermal stability of PFSA polymer composites
No full textApplication of Tomographic PIV in a Transonic Cascade
No full textThe contribution describes the implementation of Tomographic PIV in order to measure the three dimensional corner flow in a highly loaded compressor cascade in a transonic cascade wind tunnel at Mach number M1=0.68. The flow is dominated by a corner vortex which is driven by the pitch-wise pressure gradient between pressure and suction side. The vortex causes a flow separation between the sidewall and the blade. Especially the high shear between the main passage flow and the corner vortex induces strong velocity fluctuations which are responsible for the majority of total pressure losses in a compressor cascade. Furthermore the corner separation leads to blockage effects which limit the mass flow capacity of the cascade
Two-phase flow pattern measurements with a wire mesh sensor in a direct steam generating solar thermal collector
No full text"Profile-PIV" - More than just an optical hotwire: New potentials of particle image velocimetry in boundary layer research
No full textThe ISFV Asanuma Award lecture was held by the author during the 18th International Symposium of Flow Visualization held in Zurich, Switzerland, in June 2018. It provided an overview of the development, implementation and application of a recently developed variant of the particle image velocimetry (PIV) technique. The so-called "profile-PIV" approach utilizes high aspect ratio image formats to capture velocity data along narrow strips rather than providing the nearly square flow maps characteristic of PIV. Using a high-speed camera, the smaller image format allows the image capture at frame rates up to and beyond 100 kHz such that converged velocity statistics become feasible when using sample counts of similar magnitude. The narrow field of view permits a proportional reduction of the laser power required for particle illumination. For medium speed air flows (U < 10 m/s) a CW laser is suitable, whereas pulsed diode lasers are required at higher velocities. When operated with high image magnification near 1:1, the technique provides access to near-wall velocity statistics of boundary layer flows, in particular, to recover the mean and unsteady wall shear stress, even at higher shear Reynolds numbers, provided the viscous scales can still be resolved by the imager's pixels. The potential of the "profile-PIV" technique is demonstrated with examples from a variety of recent applications is given, mainly in the area of turbulent boundary layer investigation
Flora of the islands of Lake Yesa
No full textBotāniķa Aleksandra Villerta (1907 - 1941) darbs zinātņu kandidāta grāda iegūšanai par Ežezera salu floru. Darba pielikumā pārskata tabula par salā fiksētajiem augiem un autora zīmēta ezera karte. Darbs glabājas Latvijas Universitātes Muzeja Botānikas un mikoloģijas kolekcijā.The work of botanist Alexander Willert (1907 - 1941) for the candidate of sciences degree on the flora of the Ežezers Islands. In the appendix of the work, a review table of the plants fixed on the island and a map of the lake drawn by the author. The work is stored in the Botany and Mycology collections of Museum of the University of Latvia
... Gud er i psyken er i Gud er i psyken er i ...: fænomenologiske variationer over et religiøst tema
No full textParts of a manuscript, on which the author is presently working, are presented and discussed. The manuscript as a whole is an elaboration on the concept of Guiding Images, i.e. 'packages' of phenomenal material, that client-systems may internalize andmake practical use of in the context of psycho-social professional helping relationships (therapy, consultation etc.). The writing process, that brought the manuscript into being, was itself energized through the emergence of a wealth of concrete guiding images in the form of night dreams or complex verbal 'messages' with which the author supplied himself in a kind of quasi-professionel, but non-conscious self-help relationship. Amongst these guiding images, many had a marked religious colouring, and they are the ones presented in the article. The text is structured through seven consecutive headlines, each of which is a tentative programmatic statement concerning the nature of God or holiness within the article's personal-phenomenological perspective.Et empirisk materiale bestående af tekst-dele fra et manuskript, som artikel-forfatteren aktuelt har under udarbejdelse, fremlægges i systematiseret og kommenteret form. Manuskriptet som et hele tager udgangspunkt i et begreb: Styrebilleder, som er en betegnelse for forestillings-komplekser, som klient-systemer kan tage til sig og bruge indenfor rammerne af psyko-socialt professionelt hjælpearbejde (terapi~ konsultation m.m.). Manuskriptets egen skriveproces prægedes af at blive drevet frem af styrebilleder: nattedrømme og sproglige 'budskaber~ som forfatteren uden bevidst styring udstyrede sig selv med i en art pseudo-professionel selvhjælps-relation. Blandt disse styrebilleder havde mange en klart religiøs farvning, og det er disse, som præsenteres ved hjælp af en serie på syv forskellige overskrifter, som hver især udgør en tentativ bestemmelse af Guds eller det helligesnatur indenfor rammerne af artiklens personligt-fænomenologiske perspektiv
Particle image velocimetry of highly luminescent, pressurized combustion flows of aero engine combustors
No full textThis contribution describes recent efforts leading toward the successful application of particle image velocimetry (PIV) in highly luminescent flames avoiding saturation of the second frame of commonly available double shutter PIV cameras, which is usually inevitable when using their interline-transfer CCD sensors. Information on fuel placement, reaction zone and temperature field among other quantities can be provided by frequently used spectroscopic techniques. The velocity information is of equal importance in providing insight into the convective transport of reactants and their products. This flow field data can be achieved by PIV using a dual sensor camera setup splitting the optical path with a beamsplitter cube. By exposing each sensor separately in the sub-microsecond range saturation due to flame luminosity can be sufficiently reduced to allow reliable measurement in pressurized combustion
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