50 research outputs found
The use of hydraulic models in the design of suspended-load samplers
The amount of suspended solid material transported by a stream is usually determined by making measurements of sediment-content and of velocity at many points in the cross-section and integrating the results. The number of sampling points required will depend upon the degree of accuracy necessary, and, according to O'Brien [see 1 of “References” at end of paper], upon our knowledge of turbulent flow and its relation to sediment-transportation.
The suspended-load samplers used for these measurements may be divided into two classifications, depending upon the length of the sampling period. One might be called the integrating or continuous sampler, and the other the instantaneous or grab sampler. Turbulent fluctuations cause the sediment-content at any point in a stream to be continually-varying; therefore, only an integrated sample, taken over a period of time long enough to get an average concentration, can truly represent the sediment-content. This integration may be made with a continuous sampler of the suction-nozzle type, which maintains the same velocity at the entrance as the undisturbed velocity of the stream at that point. (Continuous suction-nozzle samplers are now being used in the Cooperative Laboratory of the Soil Conservation Service at the California Institute of Technology.) The mean concentration may also be obtained by combining a number of small grab-samples which show the true instantaneous sediment-content
Designs for suspended-load samplers based upon an experimental investigation of the disturbances caused by the instruments and analysis of sediment-laden flow
Measurements of soil losses and the determination of the
rate of silt transportation by streams have disclosed the need for more efficient apparatus for sampling the suspended load. This equipment is needed especially by the Soil Conservation Service for use when the fundamentals of sediment transportation are being studied or when reliable results are required. Since most of the equipment previously used produces disturbances that affect concentration measurements, more accurate samplers are necessary. Consequently, in this investigation of sampling equipment, experiments which give an indication of the absolute accuracy, rather than a comparison between instruments of unknown accuracy, are made the
basis for the practical designs
Reaction of the Wall of an Entrance Cavity Against the Afterbody of a Projectile
The cavity phase of the water entry of a projectile is described and the results are presented for the beginning of an experimental investigation of the hydrodynamic forces that affect projectile motion within a cavity. Lift-force measurements were made on two afterbody shapes that were supported so that they dug into the surface of a flowing stream of water. The similarity between these tests of models in the Free-Surface Water Tunnel and operating conditions of a full-scale projectile is discussed
Badhwar-O'Neill 2011 Galactic Cosmic Ray Model Update and Future Improvements
The Badhwar-O'Neill Galactic Cosmic Ray (GCR) Model based on actual GCR measurements is used by deep space mission planners for the certification of microelectronic systems and the analysis of radiation health risks to astronauts in space missions. The BO GCR Model provides GCR flux in deep space (outside the earth's magnetosphere) for any given time from 1645 to present. The energy spectrum from 50 MeV/n - 20 GeV/n is provided for ions from hydrogen to uranium. This work describes the most recent version of the BO GCR model (BO'11). BO'11 determined the GCR flux at a given time applying an emperical time delay function to past sunspot activity. We describe the GCR measurement data used in the BO'11 update - modern data from BESS, PAMELA, CAPRICE, and ACE emphasized more than the older balloon data used for the previous BO model (BO'10). We look at the GCR flux for the last 24 solar minima and show how much greater the flux was for the cycle 24 minimum in 2010. The BO'11 Model uses the traditional, steady-state Fokker-Planck differential equation to account for particle transport in the heliosphere due to diffusion, convection, and adiabatic deceleration. It assumes a radially symmetrical diffusion coefficient derived from magnetic disturbances caused by sunspots carried outward by a constant solar wind. A more complex differential equation is now being tested to account for particle transport in the heliosphere in the next generation BO model. This new model is time-dependent (no longer a steady state model). In the new model, the dynamics and anti-symmetrical features of the actual heliosphere are accounted for so emperical time delay functions will no longer be required. The new model will be capable of simulating the more subtle features of modulation - such as the Sun's polarity and modulation dependence on gradient and curvature drift. This improvement is expected to significantly improve the fidelity of the BO GCR model. Preliminary results of its performance will be presented
Single Event Effects Testing For Low Earth Orbit Missions with Neutrons
Neutrons can effectively be used to screen electronic parts intended to be used in Low Earth Orbit. This paper compares neutron with proton environments in spacecraft and discusses recent comparison testing
A Bronze Age hilltop cemetery complex: Ballon Hill, Co. Carlow
Situated towards the middle of the relatively flat expanse between the
Blackstairs and Wicklow mountains to the east and the Castlecomer
plateau to the west, Ballon Hill is a conical-shaped hill aligned
northwest-southeast in otherwise unremarkable topography. Rising to
only 130m above sea-level, the surrounding countryside elevates the hill
into a topographical focal point. This low yet prominent hill appears to
have attracted considerable attention in the Early Bronze Age from
possibly as early as 2200 BC when it was chosen as a burial place. In
the 1850s and 1860s, ' diggings 'were carried out on the hill by the then
landowners to try to recover so-called ' pans ' or ' crocks ' that were
reportedly being found following tree-planting and quarrying works.
Three publications on these ' diggings 'appeared in the 1850s and 1860s
describing the uncovering of numerous artefacts. The Ballon Hill
Archaeology Project was established to bring together all this disparate
information and to try to understand the place of Ballon Hill in the burial
record of the Irish Bronze Age. It appears at least three burial
monuments, including a burial mound and two barrow monuments, were
constructed during the Early Bronze Age with numerous other burials
placed over much of the hill. There is an absolute minimum of 23 pottery
vessels and arguably a minimum of 38 vessels from Ballon Hill with all
extant vessels dating to the Early Bronze Age
Pleasure and pedagogy: the consumption of DVD add-ons among Irish teenagers
This article addresses the issue of young people and media use in the digital age, more specifically the interconnection between new media pleasures and pedagogy as they relate to the consumption of DVD add-ons. Arguing against the view of new media as having predominantly detrimental effects on young people, the authors claim that new media can enable young people to develop media literacy skills and are of the view that media literacy strategies must be based on an understanding and legitimating of young people's use patterns and pleasures. The discussion is based on a pilot research project on the use patterns and pleasures of use with a sample of Irish teenagers. They found that DVDs were used predominantly in the home context, and that, while there was variability in use between the groups, overall they developed critical literacy skills and competences which were interwoven into their social life and projects of identity construction. The authors suggest that these findings could be used to develop DVDs and their add-on features as a learning resource in the more formal educational setting and they go on to outline the potential teaching benefits of their use across a range of pedagogical areas
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin