scholarly journals COMPARISON BETWEEN THE RESULTS OF LITTORAL-DRIFT COMPUTATIONS AND CUBATURE OF DEPOSITS IN A DREDGED CHANNEL

1974 ◽  
Vol 1 (14) ◽  
pp. 42
Author(s):  
V.F. Motta ◽  
J.V. Bandeira
Keyword(s):  
Time Interval ◽  
Littoral Drift ◽  
Monthly Basis ◽  
Wave Characteristics ◽  
Order Of Magnitude ◽  
Annual Volume ◽  
Offshore Oil ◽  
Remarkable Agreement

The total annual volume of littoral drift on either side of the mouth of Sergipe estuary, in the Northeast of Brazil, has been de_ termined by applying Caldwell's, Castanho's and Bijker's methods to the wave characteristics that had been recorded at a twenty-metre depth of water, over a whole year, for the design of an offshore oil terminal. The three computation methods yielded the same order of maj> nitude which was found to amount to about 80000Om^/year. The dominant drift is s outhwes tward, and its predicted amount is 660000m-*/year. It was also found that although the three methods lead to total re suits of the same order of magnitude, they do not agree as to the vari^ ation of littoral drift over the year for the s ame waves. An eight-metre deep shipping channe 1 has been dredgedaccross the bar. The channel was surveyed in December 1971, August and Decem ber 1972, and a cubature of the deposits was made after the littoraldrift computations had been carried out. As the latter had been per formed on a monthly basis, a comparison became possible between pre dieted and actual volumes of deposits for the same lengths of time. The predicted volumes for the whole year were found to be from 34 to 46% greater than the actual results. However, for the time interval August-December 1972 a remarkable agreement was found be^ tween predicted and actual results.

scholarly journals Wave length and celerity downstream from a hydraulic jump

RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Ana Paula Gomes ◽  
Eduardo Pivatto Marzec ◽  
Luiz Augusto Magalhães Endres
Keyword(s):  
Dispersion Equation ◽  
Hydraulic Jump ◽  
Wave Length ◽  
Vortex Formation ◽  
Wave Period ◽  
Time Interval ◽  
Significant Wave ◽  
Wave Characteristics ◽  
Wave Celerity

ABSTRACT The wave period, i. e., the time interval which corresponds to a complete oscillation, is an important parameter of wave characterization. It allows the estimation of other important wave characteristics such as the length and celerity. This study aims at describing the results of a relationship among the significant, mean, and peak periods of waves generated downstream from a hydraulic jump. The frequency of vortex formation in the roller region within the hydraulic jump was used. Besides those relationships, wave lengths were also determined by the dispersion equation by considering the wave-current overlapping effect in order to identify the wave celerity. Estimated results of wave celerity were compared to their experimental results. Our findings allowed us to identify that the significant wave period was the most representative period for the characterization of a wave downstream from a hydraulic jump.

P34 Quality improvement project aimed at reducing gentamicin errors in neonates

2018 ◽  
Vol 103 (2) ◽  
pp. e1.38-e1 ◽  
Author(s):  
Calvert Heather ◽  
Makhalira Aubrey
Keyword(s):  
Quality Improvement ◽  
Transitional Care ◽  
Action Plan ◽  
Quality Improvement Project ◽  
Time Interval ◽  
List Type ◽  
Open Communication ◽  
Monthly Basis ◽  
Improvement Project ◽  
High Dependency

AimA level 3 tertiary neonatal unit with a capacity of 40 cots providing intensive care, high dependency care, special care & transitional care services, had 18 gentamicin errors reported between January and June 2017, with 84% errors occurring at prescribing and 16% errors in administration. The majority of errors (67%) were due to the complexity of calculating a 36-hourly time interval between doses. A quality improvement project was undertaken with the aim of reducing the number of gentamicin errors on the unit over a 3 month period.MethodAn overview of all gentamicin errors were presented to the multidisciplinary team (MDT) with a view of gathering ideas for improvement to ensure a team based approach. An action plan was put in place in line with National Patient Safety Agency (NPSA) recommendations1 and initiated in July 2017 based on a plan-do-study-act (PDSA) model.ResultsThe PDSA cycles included:a simplified and standardised dosing interval for dosing of gentamicin after the first dose.an updated local monograph with dosing intervals and example prescription.posters displayed in prescribing areas to promote safe and focused prescribing.a feedback session to the full MDT team regarding improvements made and further feedback.ensure compliance with policy by promoting updated guideline & on going error monitoring.consideration of alternative lower risk antibiotic in low risk babies.incorporation of gentamicin prescribing exercise as part of the new doctor induction. The following interventions will be evaluated in 3 months using Datix reported errors before and after implementation. Sequential PDSA cycles will then be conducted for learning and improvement.ConclusionA team based approach, using open communication with regular feedback and review is essential in order to improve the quality of prescribing and gain engagement from medical and non-medical prescribing colleagues. Further audit will be undertaken on monthly basis to evaluate the implementation of improvement measures.

Nonlinear radio-frequency response of a non-uniform plasma slab–condenser system with realistic density and velocity profiles

1972 ◽  
Vol 8 (2) ◽  
pp. 113-126 ◽  
Author(s):  
R. Ballieu ◽  
A. M. Messiaen ◽  
P. E. Vandenplas
Keyword(s):  
Plasma Sheath ◽  
Nonlinear Behaviour ◽  
Bounded Plasma ◽  
Plasma Slab ◽  
Order Of Magnitude ◽  
Classical Plasma ◽  
Sophisticated Model ◽  
Density Perturbations ◽  
Remarkable Agreement ◽  
Uniform Plasma

The nonlinear behaviour of a realistic one-dimensional bounded plasma (specifically, the classical plasma slab–condenser system) is computed by an iterative perturbation method. The results indicate, somewhat unexpectedly, that the influence of the r.f. field on the static density profile and on the resonance spectrum is much smaller than would have been inferred from a previous analysis of an unbounded plasma. However, this approach is inherently limited by the fact that, even for not too high r.f. fields, the electron density perturbations can become of the same order of magnitude as the static density in the tenuous plasma sheath near the wall. The resonance curves obtained with this sophisticated model show quite remarkable agreement with existing experimental data.

The Monte Carlo Independent Column Approximation’s Conditional Random Noise: Impact on Simulated Climate

2005 ◽  
Vol 18 (22) ◽  
pp. 4715-4730 ◽  
Author(s):  
P. Räisänen ◽  
H. W. Barker ◽  
J. N. S. Cole
Keyword(s):  
Monte Carlo ◽  
Global Climate ◽  
Random Noise ◽  
Radiative Heating ◽  
Time Interval ◽  
Additional Time ◽  
Time Step ◽  
Order Of Magnitude ◽  
Independent Column ◽  
The Impact

Abstract The Monte Carlo Independent Column Approximation (McICA) method for computing domain-average radiative fluxes is unbiased with respect to the full ICA, but its flux estimates contain conditional random noise. Results for five experiments are used to assess the impact of McICA-related noise on simulations of global climate made by the NCAR Community Atmosphere Model (CAM). The experiment with the least noise (an order of magnitude below that of basic McICA) is taken as the reference. Two additional experiments help demonstrate how the impact of noise depends on the time interval between calls to the radiation code. Each experiment is an ensemble of seven 15-month simulations. Experiments with very high noise levels feature significant reductions to cloudiness in the lowermost model layer over tropical oceans as well as changes in highly related quantities. This bias appears immediately, stabilizes after a couple of model days, and appears to stem from nonlinear interactions between clouds and radiative heating. Outside the Tropics, insignificant differences prevail. When McICA sampling is confined to cloudy subcolumns and when, on average, 50% more samples, relative to basic McICA, are drawn for selected spectral intervals, McICA noise is much reduced and the results of the simulation are almost statistically indistinguishable from the reference. This is true both for mean fields and for the nature of fluctuations on scales ranging from 1 day to at least 30 days. While calling the radiation code once every 3 h instead of every hour allows the CAM additional time to incorporate McICA-related noise, the impact of noise is enhanced only slightly. In contrast, changing the radiative time step by itself produces effects that generally exceed the impact of McICA’s noise.

scholarly journals Nanocracks upon Fracture of Oligoclase

2021 ◽  
Vol 57 (6) ◽  
pp. 894-899
Author(s):  
V. I. Vettegren ◽  
A. V. Ponomarev ◽  
R. I. Mamalimov ◽  
I. P. Shcherbakov
Keyword(s):  
Free Radicals ◽  
Power Law ◽  
Time Interval ◽  
Electron Traps ◽  
Surface Areas ◽  
Electronically Excited ◽  
Order Of Magnitude ◽  
20 Nm

Abstract—The spectrum of fractoluminescence (FL) upon fracture of the surface of oligoclase is obtained. The analysis of the spectrum has shown that fracture of crystals leads to the formation of electronically excited free radicals ≡Si−O• and Fe3• ions as well as electron traps. FL consisted of a set of the signals with the intensities varying by an order of magnitude. The duration of the signals was ~50 ns and the time interval between them varied from ~0.1 to 1 μs. Each signal contained four maxima associated with the destruction of barriers preventing the motion of dislocations along the sliding planes. These breakthroughs cause the formation of the smallest (“primary”) cracks. All other, larger cracks are formed by the coalescence of the “primary” cracks. The sizes of “primary” cracks range from ~10 to 20 nm and the time of their formation is 16 ns. The distribution of cracks by size (surface areas of crack walls) is power law with the exponent –1.9.

scholarly journals THE LENSE–THIRRING EFFECT IN THE JOVIAN SYSTEM OF THE GALILEAN SATELLITES AND ITS MEASURABILITY

2005 ◽  
Vol 14 (12) ◽  
pp. 2039-2049 ◽  
Author(s):  
LORENZO IORIO ◽  
VALÉRY LAINEY
Keyword(s):  
Initial Conditions ◽  
Optical Observations ◽  
Time Interval ◽  
Maximum Magnitude ◽  
Galilean Satellites ◽  
Recent Developments ◽  
Order Of Magnitude ◽  
General Relativistic ◽  
Analytical Development ◽  
Jovian System

We investigate the possibility of measuring the post-Newtonian general relativistic gravitomagnetic Lense–Thirring effect in the Jovian system of its Galilean satellites Io, Europa, Ganymede and Callisto in view of recent developments in processing and modeling their optical observations spanning a large time interval (125 years). The present day best observations have an accuracy between several kilometers to few tens of kilometers, which is just the order of magnitude of the Lense–Thirring shifts of the orbits of the Galilean satellites over almost a century. From a comparison between analytical development and numerical integration it turns out that, unfortunately, most of the secular component of the gravitomagnetic signature is removed in the process of fitting the initial conditions. Indeed, an estimation of the magnitude of the Lense–Thirring effect in the ephemerides residuals is given; the resulting residuals have a maximum magnitude of 20 meters only (over 125 years).

Geotubes vs. mulching for post-fire erosion mitigation in eucalypt vs. pine plantations in Central Portugal vs. Galicia

2021 ◽  
Author(s):  
Ana Isabel Machado ◽  
Bruna Oliveira ◽  
Dalila Serpa ◽  
Martha Santos ◽  
Fátima Jesus ◽  
...  
Keyword(s):  
Sediment Traps ◽  
Mitigation Measures ◽  
Runoff Generation ◽  
Monthly Basis ◽  
Erosion Rates ◽  
The Usa ◽  
Order Of Magnitude ◽  
Central Portugal ◽  
Erosion Mitigation ◽  
Study Sites

<p>Wildfires are well-known to negative affect forest both directly and indirectly, due to fire-enhanced runoff generation and the associated losses of wildfire ash, soil, organic matter and nutrients. In turn, post-fire runoff and erosion can, promote eutrophication and contamination of downstream surface water bodies. A variety of erosion mitigation measures have been tested in recently burnt areas, with especially mulching with straw having been applied in operational post-fire land management in the USA and Galicia. The present work, evaluates the effectiveness of a new erosion mitigation strategy, using geotubes filled with mycotechnosols and straw, and compares it to that of mulching. This was done for the two prevalent forest types in central Portugal and Galicia, i.e. an eucalypt plantation in Central Portugal and a pine plantation in Galicia that both burnt during the summer of 2019.  Both study sites were instrumented with 9 bounded erosion plots of 16m<sup>2</sup> with sediment traps at the bottom of the plots, divided over three blocks. The three treatments of doing nothing, mulching and geotubes were applied to one plot per block. In total, 4 geotubes were placed in each plot to create a barrier in the middle of the plot and at the bottom, just before the sediment deposition zone at the plot outlet. Mulching was done with chopped eucalypt bark at the eucalypt site and with pine needles at the pine site, at application rates of roughly 250 g m<sup>-2</sup>. Eroded sediments were collected on a bi-weekly to monthly basis, depending on occurrence of rain, during the first post-fire hydrological year. The results showed that the erosion rates of the control plots differed about one order of magnitude between the two sites, amounting to  an average of 11 Mg  ha<sup>-1 </sup>y-<sup>1</sup> at the pine site as opposed to 1.0 Mg ha<sup>-1</sup> y-<sup>1</sup>  at the eucalypt site. This discrepancy was probably related to soil type (derived from granite vs. schist) and stoniness. Mulching was somewhat more effective than the geotubes at the pines site, with reduction in average annual erosion rates of 84 and 77%, respectively. The opposite was true at the eucalypt site, with annual erosion reductions of on average 75 and 62%. The use of geotubes would therefore seem a further option for forest and water resources managers to decrease markedly the risks of both elevated and reduced soil (fertility) losses from recently burnt hillslopes and the associated risks for downstream values.</p>

scholarly journals Seeing the unseen—the iceberg phenomenon in the first months of the COVID19 pandemic

2021 ◽  
Vol 2090 (1) ◽  
pp. 012021
Author(s):  
Dragos-Victor Anghel ◽  
loan Tudor Alexandru Anghel
Keyword(s):  
Time Series ◽  
Characteristic Time ◽  
Large Population ◽  
Sir Model ◽  
Time Interval ◽  
Order Of Magnitude

Abstract We analyze the evolution of the COVID19 infections in the first months of the pandemics and show that the basic compartmental SIR model cannot explain the data, some characteristic time series being by more than an order of magnitude different from the fit function over significant parts of the documented time interval. To correct this large discrepancy, we amend the SIR model by assuming that there is a relatively large population that is infected but was not tested and confirmed. This assumption qualitatively changes the fitting possibilities of the model and, despite its simplicity, in most cases the time series can be well reproduced. The observed dynamic is only due to the transitions between two infected compartments, which are the unconfirmed infected and the confirmed infected, and the rate of closing the cases (by recovery or death) in the confirmed infected compartment. We also discuss some relevant extensions of this model, to improve the interpretation and the fitting of the data. These findings qualitatively and quantitatively evidences the “iceberg phenomenon” in epistemology.

scholarly journals Фракто- и фотолюминесценция кварца при разрушении

2021 ◽  
Vol 63 (8) ◽  
pp. 1120
Author(s):  
В.И. Веттегрень ◽  
А.Г. Кадомцев ◽  
И.П. Щербаков ◽  
Р.И. Мамалимов
Keyword(s):  
Rate Constants ◽  
Time Interval ◽  
Quartz Surface ◽  
Micro Cutting ◽  
Pl Spectra ◽  
Order Of Magnitude ◽  
Average Size

The fractoluminescence (FL) spectra at the destruction of the quartz surface by "micro-cutting" of diamond micro crystals and impact on its surface with a steel striker and photoluminescence (PL) spectra after "micro-cutting" are obtained. Band of 2.12 eV in the FL spectra was attributed to excited Si-O● radicals. FL consist from a set of signals whose duration was ≈ 50 ns, and their intensity varies by an order of magnitude. The time interval between the signals varies from ≈ 0.1 to several µs. Signals generated at impact contain five, and at "micro-cutting" contain four superimposed maxima. It is assumed that the FL signals appear when the barriers that prevent the movement of dislocations along the sliding planes breaks, and the smallest "primary" cracks are formatted. The rate constants of growth the cracks and fading of FL after the cracks stops are determined. The average size of the "primary" cracks surfaces after impact is ≈ 5 nm2, and after "micro-cutting" is ≈ 25 nm2. In the PL spectra after the fracture, a band of 2.4 eV was observed, which is attributed to non excited ≡Si-O- radicals on the cracks surface after their stop.

scholarly journals A COMPREHENSIVE SEDIMENT BUDGET FOR THE MISSISSIPPI BARRIER ISLANDS

2012 ◽  
Vol 1 (33) ◽  
pp. 81 ◽  
Author(s):  
Dirk-Jan Walstra ◽  
J. De Vroeg ◽  
J. Van Thiel de Vries ◽  
C. Swinkels ◽  
A. Luijendijk ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Barrier Islands ◽  
Sediment Budget ◽  
Littoral Drift ◽  
Island Restoration ◽  
Mississippi Sound ◽  
Longshore Transport ◽  
Sound Side ◽  
Order Of Magnitude

In order to conceive any realistic plan for post-Katrina island restoration, it is necessary to understand the physical processes that move sand along the littoral drift zone off the coast of Mississippi. This littoral zone influences the character of the Mississippi barrier islands as they exist in an ever changing cycle. To help in this understanding, a sediment transport model was conducted to establish a current sediment budget for the islands. This study evaluated the existing regional sediment transport magnitudes and directions for the Mississippi and Alabama barrier islands fronting Mississippi Sound including daily conditions and hurricanes. A method was developed to incorporate all relevant hurricanes from 1917 to 2010 in the analysis. For the long term average net longshore transport along the southern shorelines of the barriers (i.e. exposed to the Gulf of Mexico), the contribution of year-averaged conditions and hurricanes are of similar order of magnitude, although the mean annual percentage occurrence of hurricanes is no more than about 3%. Along the northern shores (Mississippi Sound side) the transport is considerably smaller and the contributions of cold fronts and hurricanes to the sediment transports are more or less equal. For the year-averaged conditions (excluding hurricanes) a westward directed net transport is found. The net effect of the historic hurricanes is also westward in direction. However, for individual hurricanes (e.g. Camille and Katrina) the net transport along Ship Island can be directed eastward due to the dominance of ebb flows after the eye of the hurricane had passed.

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