2,233 research outputs found
Dewatering effects on the erodibility of newly deposited cohesive beds by unidirectional currents
No full textA series of laboratory experiments on cohesive sediments under inorganic conditions was undertaken in order to evaluate the impact of fluid bed shear stress on the build-up of bed resistance to erosion with time. The importance of small pressures due to flowing water to increase bed strength is presented. It is also shown that the susceptibility of a cohesive bed to changes in its erodibility is related to deposited bed thickness due to sediment disturbance caused by dewatering from the consolidating bed. Laboratory experiments that use beds deposited from suspension should thus report the thickness of the bed prior to resuspension.Fil: Gomez, Eduardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Amos, Carl L.. Southampton Oceanography Centre; Reino Unid
Amos Stagg Biography
No full textThis is a brief biography of Springfield College faculty member and alumnus Alonzo Amos Stagg. An All-American Yale player, Amos Alonzo Stagg (1862-1965) brought football to the YMCA Training College (now Springfield College) and coached the institution’s first team in 1891. This document is most likely written and created by someone at Springfield College, but the exact author is unknown.For more information on Amos Alonzo Stagg, see: https://springfield.as.atlas-sys.com/agents/people/661Paper is fragile
Carl E Brown Folder
No full text53 pages of family history documents containing and related to Carl Elliott Brown; Ida Louise Brown; Ida Louise Harrington; Amos Brown; Virgil DeWitt Harrington; Betty Harwood - including: Pictures; photos; autobiographies; index; legal document
An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada
No full textSutherland, T.F. and Amos, C.L., 2020. An in situ assessment of seabed stability in Baynes Sound, British Columbia, Canada. Journal of Coastal Research, 36(3), 472-486. Coconut Creek (Florida), ISSN 0749-0208. The Sea Carousel, an annular flume, was deployed to examine (in situ) fundamental parameters of seabed stability in Baynes Sound, British Columbia, Canada. Sediment grain size, water and organic contents, and chlorophyll and phaeopigment concentrations were collected to establish a hierarchy of factors associated with seabed stability. Sediment stability increased toward the Sound entrance in concert with decreases in water, organic, and silt-clay contents and a transition from cohesive to noncohesive properties. Bed-stress estimates, based on the quadratic stress law and turbulent kinetic energy (TKE) methods, showed a decrease in the drag coefficient from the inner (0.04) to the outer (0.0015) Sound. Surface erosion thresholds ranged between 0.04 to 0.28 Pa, whereas the friction coefficients (e.g., the failure envelop) were on average 12°, representing normally consolidated sediments. Type I (floc) erosion occurred at low shear stresses, whereas type II (mass) erosion happened at higher values. Erosion rates (E, for type I erosion) fitted a power function of excess shear stress (E
m = τ0 - τcrit,z)m with zero offset, where 0.81 < m < 2.32. The lowest and highest values for a given excess-shear stress occurred in the inner Sound and outer Sound, respectively. Settling of (resuspended) sediment after an exponential decay law [d(SSC)/dt] = SSC0 (expkt), where k fell within that of published values (3 < k < 539). Higher values of k (fastest settling) were observed in the inner Sound relative to the outer Sound. The sedimentation diameter (ds) fell in a coarse-silt to fine-sand range and was larger in the outer Sound, reflecting a coarsening of bed sediments.
</p
Valuation of the ecosystem services of beach nourishment in decision-making: The case study of Tarquinia Lido, Italy
No full textCost Benefit Analysis (CBA) is a systematic process commonly employed by the US Army Corps of Engineers (USACE) to assess primarily benefits stemming from storm damage reduction and recreation enhancement by beach protection. The USACE goal is to quantify federal money disbursement to local communities to counter the consequences of coastal erosion. The EU has recommended the use of CBA for shoreline management (both at regional and local scales), looking not only at the financial aspects of project assessment, but also at non-market benefits (ecosystem services of the beaches) and environmental costs, assessed on a broad time horizon in a given sediment cell. In this paper, several ecosystem services provided by beach protection are considered and some of them monetised to assess the local net benefits of a nourishment project carried out along the Tyrrhenian coast of Italy. The paper shows that free riding emerges by the public supply of coastal protection, and that it could be possibly partially removed charging the cost of beach maintenance to the local users. In addition, supply of coastal protection may generate negative environmental externalities. However, costs of environmental damage of the beach nourishment are not easy to be internalised. This suggests alternative market mechanisms (charges or insurance premiums) to reduce the development pressure on coastal areas subject to high rates of erosion or to explore the adoption of subsides such as payments for ecosystem services (PES) at seascape scales
User guide to the Centre for Population Change GHS database 1979-2009
No full textMáire Ní Bhrolcháin originated the proposal to create a time-series database of General Household Survey demographic histories from the 1970s to the present and was Principal Investigator on the project to create the data file. Éva Beaujouan assembled the database, with assistance from Mark Lyons-Amos, under the direction of Máire Ní Bhrolcháin and Ann Berrington. All authors have contributed to the compilation of this User Guide but Éva Beaujouan is its principal author
Edmond Jacob, Carl-A. Keller, Samuel Amsler, Osée, Joël, Amos, Abdias, Jonas, 1982
No full textBogaert Pierre-Maurice. Edmond Jacob, Carl-A. Keller, Samuel Amsler, Osée, Joël, Amos, Abdias, Jonas, 1982. In: Revue théologique de Louvain, 14ᵉ année, fasc. 2, 1983. p. 239
Sea surface temperature trends in the coastal zone of southern England
No full textSea surface temperature (SST) trends along the south coast of England (northern English Channel) were examined based on data from systematic buoy measurements deployed by the National Network of Regional Coastal Monitoring Programmes of England (NNRCMP) since 2003. These data were supplemented with the following: 1) long-term, coastal SST measurements by the Centre for Environment, Fisheries and Aquaculture Science (CEFAS); 2) global data sets compiled by the Hadley Centre since 1900, and 3) satellite-derived observations from Moderate Resolution Imaging Spectroradiometer (MODIS Aqua) since 2002. These data sets were used to evaluate de-seasoned nearshore trends in SST along the south coast of England, and examine links to regional ocean-atmosphere teleconnections. The analyses of long-term, CEFAS data (collected at five sites along the Southern English Coast) support the proposal that prior to the mid-1980s there were no de-seasoned trends in SST and conditions from year to year were relatively stable. Subsequently, inter-annual fluctuations appear to have increased and are , associated with a period of warming between 1985 and 2003 (0.28oC/decade). Post 20052003, interannual fluctuations in SST monitored by the NNRCMP data buoys continued, and the warming trend appears to be greater (0.42 oC/decade). This trend in SST is greatest in the nearshore and decreases with distance offshore in a systematic fashion. The warming in SST also varied greatly from month to month. The greatest warming took place from December to March, whilst the least heating (and sometimes cooling) occurred between September and November. Analysis of Hadley (HadSST1.1) and MODIS data sets substantiated these trends. The greatest warming (post 2003) was found west of Portland Bill (up to 0.76 oC/decade) and decreased towards the Strait of Dover. Despite this west-to-east trend, all 12 NNRCMP stations between Penzance and Folkestone showed remarkably similar results, suggesting regional and global sources of heat rather than local sources. This is further corroborated through wavelet coherence analysis linking SST anomalies to regional/global ocean-atmosphere teleconnection indices at seasonal scales
Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada
No full textA benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ϵ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f-5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10-3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (ws) scaled with the friction velocity (u*) in the form ws/u* = D*/8. The median size of resuspended aggregates (df) scaled inversely with dissipation (ϵ) in the form df = 5 × 10-6ϵ-0.24m, which is close to the relationship found in the literature.</p
- …
