2,620 research outputs found
Wide bandgap collector III-V double heterojunction bipolar transistors
No full textThis thesis is devoted to the study and development of Heterojunction Bipolar Transistors (HBTs) designed for high voltage operation. The work concentrates on the use of wide bandgap III-V semiconductor materials as the collector material and their associated properties influencing breakdown, such as impact ionisation coefficients. The work deals with issues related to incorporating a wide bandgap collector into double heterojunction structures such as conduction band discontinuities at the base-collector junction and results are presented which detail, a number of methods designed to eliminate the effects of such discontinuities. In particular the use of AlGaAs as the base material has been successful in eliminating the conduction band spike at this interface. A method of electrically injecting electrons into the collector has been employed to investigate impact ionisation in GaAs, GaInP and AlInP which has used the intrinsic gain of the devices to extract impact ionisation coefficients over a range of electric fields beyond the scope of conventional optical injection techniques. This data has enabled the study of ''dead space'' effects in HBT collectors and have been used to develop an analytical model of impact ionisation which has been incorporated into an existing Ebers-Moll HBT simulator. This simulator has been shown to accurately reproduce current-voltage characteristics in both the devices used in this work and for external clients. (author)SIGLEAvailable from British Library Document Supply Centre-DSC:DXN041915 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
R.M. Simmons presentation, Rena Smart book review
No full textR.M. Simmons of the Gospel Music Workshop of America gives a presentation on the African influence in the African American religious experience. He explains how African slaves brought to America their concept of music (utilitarian concept of music). Simmons further discusses the fusion between the utilitarian concept and the Western concept of religion resulting in spirituals. He also describes hymn categories in early forms of formal African American worship experiences. Simmons takes questions from the audience among which is Dr. Riggins Earl Jr. Video concludes with a book review on Christian Theology and Ethics by Rena Smart.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the National Endowment for Humanities - Humanities Collections and Reference Resources Implementation Project Grant in supporting the processing and digitization of a number of its major archival collections as part of the project: Spreading the Word: Expanding Access to African American Religious Archival Collections at the Atlanta University Center Robert W. Woodruff Library.</em
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Hourly Stream Temperature and Water Level Data from 2010 – 2024 for Headwater Streams in the Smith River Basin, Oregon
No full textDataset of hourly stream temperature and water level (stage height) data collected between 2010 and 2024 for four headwater streams that are tributaries to the Smith River in Oregon. The data files included here are hourly data (or during some time periods, hourly averages of sub-hourly data) for each of the four sites, Beaver Creek, North Sister Creek, Halfway Creek, and Panther Creek. The hourly averages were calculated in two ways, producing two sets of hourly data files for each of the four creeks. In one set, water level hourly averages were calculated using all the available data for each hour, and then the hourly averages that were less than zero were removed (the four files whose filenames have the suffix “noneg”). In the other set, water level hourly averages were calculated using all the available data for each hour, and all hourly averages, including those with water levels that were less than zero, were retained. We interpret the negative water level values as records of times when the water level in the stream was below the level of the pressure transducer, and discharge was close to zero, although there was still some water in the stream. These data were collected as part of a monitoring effort to gain data on water temperature and water level in small headwater streams with returning populations of Coho salmon in the Oregon Coast Range. These data supported research efforts by the Coastal Riverscapes Laboratory, led by Dr. Mary Santelmann at Oregon State University and Dr. Rebecca Flitcroft with the USDA Forest Service Pacific Northwest Research Station. The metadata that are specific to each site are presented below in the following order: Beaver Creek, Halfway Creek, North Sister Creek, and Panther Creek.
The filenames of the data files are as follows:
BC_TL_10_24_hourly.csv
BC_TL_10_24_hourly_noneg.csv
HF_TL_18_24_hourly.csv
HF_TL_18_24_hourly_noneg.csv
NS_TL_10_24_hourly.csv
NS_TL_10_24_hourly_noneg.csv
PC_TL_10_24_hourly.csv
PC_TL_10_24_hourly_noneg.csv
(Note: The data for rating curves that can be used to generate discharge values from these datasets are archived with the daily average data for these sites, which have been archived in a separate DOI with its own metadata file (Santelmann, M.V., Flitcroft, R.L., LovellFord, R.M., Windoloski, S.N., Munyon, J.W. 2025. Daily Stream Temperature, Water Level, and Discharge Data from 2010 – 2024 for Headwater Streams in the Smith River Basin, Oregon. Deposited in ScholarsArchive at Oregon State University. DOI: tbd
Velocity-Gradient Probability Distribution Functions in a Lagrangian Model of Turbulence
No full textThe Recent Fluid Deformation Closure (RFDC) model of lagrangian turbulence is recast in path-integral language within the framework of the Martin-Siggia-Rose functional formalism. In order to derive analytical expressions for the velocity-gradient probability distribution functions (vgPDFs), we carry out noise renormalization in the low-frequency regime and find approximate extrema for the Martin-Siggia-Rose effective action. We verify, with the help of Monte Carlo simulations, that the vgPDFs so obtained yield a close description of the single-point statistical features implied by the original RFDC stochastic differential equations
Author Correction: Global geochemical fingerprinting of plume intensity suggests coupling with the supercontinent cycle
Get PDFThe original version of this Article omitted from the author list the 4th and 5th authors, Grant Cox and Ross Mitchell, who were both at Curtin University. Consequently, the corrected version of the Acknowledgements removes the following from the original version: ‘and Ross Mitchell’. In addition, the following was added to the Author Contributions: ‘G.M.C. and R.M. were involved in an early attempt of this study.’. This has been corrected in both the PDF and HTML versions of the Article
Colonising "The Coral Island": A Postcolonial Reading of R.M. Ballantyne's Children's "Classic"
No full textstudent essayBeing written during the rise of the British Empire in the 1850sm R.M. Ballantyne's boys' adventure story "The Coral Island" is in many ways a product of its time, conveying imperial ideas and Victorian values to the young reader. Through his portrayal of the native inhabitants in relation to his descriptions of the three British protagonists, the author creates a stereotyped image of the natives as primitive savages. Due to the further use of a first person narrator and realist pretensions, the dated racist ideas become influential upon the reader. In spite of the fact that the novel has been considered as an entertaining children's classic by generations since its first publication, "The Coral Island" should not be classified as good children's literature today but should rather be historicised as a result of its controversial contents. By adopting a postcolonial approach and applying postcolonial theory in my analysis of R.M. Ballantyne's "The Coral Island", I have in this essay endeavoured to demonstrate in what ways the novel would prove problematic as a children's book today. In my first chapter I present the imperial ideas and Victorian values that are conveyed, whereas in my second chapter I discuss Ballantyne's stereotyping of the natives. As a result of my study of this novel, I have exemplified how the author portrays the three British boys as representative of the Victorian ideals of the time. I have also illustrated their assumed superiority over nature and their roles as colonisers. Furthermore, my analysis of "The Coral Island" has revealed how Ballantyne communicates both white superiority as well as the Western "oblibation" to civilise primitive people throug Christian conversion. Consequently, the novel promotes the ideology of its time. As a result of my findings, I would like to argue that "The Coral Island" should today be viewed as a text conveying historical ideas and values rather than as an exciting children's classic
Acoustic emmission gedrag van verschillende grondsoorten
No full textDit rapport vat de resultaten samen van de meetrapporten "Acoustic Emission" (A.E.) gedrag van verschillende grondsoorten door ing. F.M. Schenkeveld, LGM en "Acoustic emission laboratory testing of sand, clay and peat soils" door Prof. R.M. Koerner, Drexel University, U.S.A. Het onderzoek werd verricht in opdracht van het Centrum voor Onderzoek Waterkeringen (COW), in samenwerking met het Laboratorium voor Grondmechanica (LGM). Projectleider voor het COW was ir. A. Penning. Het doel van het onderzoek is de evaluatie van de "acoustic emission"-methode met betrekking tot stabiliteitsproblemen bij Nederlandse dijken. Tijdens het vooronderzoek is kontakt gelegd met Prof. R.M. Koerner (R.M.K.), Drexel University, U.S.A. Om een goede basis te geven aan het onderzoek werd met Prof. Koerner een gezamenlijk project uitgevoerd. "Acoustic Emissions" zijn spanningsgolven die gegenereerd worden in een materiaal onder spanning tijdens deformatie. Soms zijn deze spanningsgolven hoorbaar (kraken van hout), maar vaak niet vanwege de lage amplitude en hoge frequentie. Een piezoelectrische sensor wordt gebruikt om de "acoustic emissions" te detecteren. De opnemer produceert een electrisch signaal evenredig met de amplitude van de waargenomen trilling. Het signaal wordt dan versterkt, gefilterd en geteld of op een andere wijze gekwantificeerd. Achtergrondruis en andere ongewenste verstoringen worden gefilterd of apart gekwantificeerd en afgetrokken van de resultaten. De tellingen of andere bewerkte resultaten van de emissies worden dan gecorreleerd met het materiaal gedrag om empirisch de veiligheid van de onderzochte situatie te bepalen. Indien er geen acoustic emissions zijn is het materiaal in het algemeen in rust en stabiel. Evenwel als er emissies worden waargenomen is het materiaal in beweging, hetgeen uiteindelijk kan leiden tot bezwijken. De komponenten van het huidige "acoustic emission" systeem bestaan uit: een stalen staaf (om het signaal vanuit de grond naar een geschikt waarnemingspunt te brenger.) , een sensor (geofoon, versnellingsopnemer,hydrofoon of een andere opnemer die een mechanische trilling in een electrisch signaal omzet), een voorversterker (om het signaal te versterken indien een lange kabel wordt gebruikt), filters (om ongewenste gedeelten van het signaal te elimineren), een versterker (om het signaal verder te versterken voor signaalbewerking) en een signaalbewerkingssysteem. Het signaalbewerkingssysteem is over het algemeen een teller die telt als een bepaalde drempelwaarde wordt overschreden.TAW/EN
Value of Information Based Design of Control Software
No full textElectrical Engineering, Mathematics and Computer Scienc
Algorithms for non-parametric Bayesian belief nets
No full textElectrical Engineering, Mathematics and Computer Scienc
High dimensional dependence: Copulae, sensitivity, sampling
No full textElectrical Engineering, Mathematics and Computer Scienc
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