Instantaneous Production Research Articles

Photochemical production and loss rates of ozone at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive

Three weeks of summertime surface‐based chemical and meteorological observations at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive are used to study instantaneous photochemical production and loss rates of ozone by means of a numerical photochemical model. Results are most sensitive to the averaging scheme of data used to constrain the model and the ambient variability of the measurements. Model simulations driven by a time series of 5 min averaged data, most representative of the chemistry at the site, yield an average net photochemical ozone production of 3.6 ppbv/d. Estimates of net ozone production designed to filter out local sources, by using 1000–1400 LT median values of observations to drive the model and by excluding short‐lived hydrocarbons, give values ranging from 1 to 4 ppbv/d. These positive values of net ozone production within the marine boundary layer over Sable Island demonstrate the impact of polluted continental plumes on the background photochemistry of the region during the intensive. The dominant ambient variables controlling photochemical production and loss rates of ozone at the site during the measurement campaign appear to be levels of nitrogen oxides, ozone, nonmethane hydrocarbons, and solar intensity determined by cloud cover. The model partitioning of nitrogen oxides agrees for the most part with measurements, lending credence to calculated photochemical production and loss rates of ozone as well as inferred levels of peroxy radicals not measured at the site. Discrepancies, however, often occur during episodes of intermittent cloud cover, fog, and rain, suggesting the influence of cloud processes on air masses reaching the site.

Two-stage Rydberg charge exchange: An efficient method for production of antihydrogen

An efficient method for production of cold antihydrogen ({bar H}) is proposed. Alkali-metal atoms laser excited to a Rydberg state are charge exchanged with cold trapped positrons, producing Rydberg states of positronium. In a second Rydberg-state charge exchange, the positronium atoms give up their Rydberg positrons to cold trapped antiprotons, producing Rydberg states of {bar H}. These {bar H} atoms soon decay down to the ground state, and, because they are cold, could be trapped in a magnetic trap. The efficiency of the process results from the extremely large cross sections for Rydberg charge exchange. Classical trajectory Monte Carlo calculations indicate an {bar H} instantaneous production rate of 10{sup 6}/s. {copyright} {ital 1998} {ital The American Physical Society}

A computational fluid dynamic study of hawkmoth hovering

A computational fluid dynamic (CFD) modelling approach is used to study the unsteady aerodynamics of the flapping wing of a hovering hawkmoth. We use the geometry of a Manduca sexta-based robotic wing to define the shape of a three-dimensional 'virtual' wing model and 'hover' this wing, mimicking accurately the three-dimensional movements of the wing of a hovering hawkmoth. Our CFD analysis has established an overall understanding of the viscous and unsteady flow around the flapping wing and of the time course of instantaneous force production, which reveals that hovering flight is dominated by the unsteady aerodynamics of both the instantaneous dynamics and also the past history of the wing. <P> A coherent leading-edge vortex with axial flow was detected during translational motions of both the up- and downstrokes. The attached leading-edge vortex causes a negative pressure region and, hence, is responsible for enhancing lift production. The axial flow, which is derived from the spanwise pressure gradient, stabilises the vortex and gives it a characteristic spiral conical shape. <P> The leading-edge vortex created during previous translational motion remains attached during the rotational motions of pronation and supination. This vortex, however, is substantially deformed due to coupling between the translational and rotational motions, develops into a complex structure, and is eventually shed before the subsequent translational motion. <P> Estimation of the forces during one complete flapping cycle shows that lift is produced mainly during the downstroke and the latter half of the upstroke, with little force generated during pronation and supination. The stroke plane angle that satisfies the horizontal force balance of hovering is 23.6 degrees , which shows excellent agreement with observed angles of approximately 20-25 degrees . The time-averaged vertical force is 40 % greater than that needed to support the weight of the hawkmoth.

Response of primary producers to nutrient enrichment in a shallow estuary

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 163:89-98 (1998) - doi:10.3354/meps163089 Response of primary producers to nutrient enrichment in a shallow estuary Eleanor H. Kinney1, Charles T. Roman2,* 1Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA 2US Geological Survey, Biological Resources Division, Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA *Addressee for correspondence. E-mail: croman@gsosun1.gso.uri.edu Shallow coastal systems worldwide are exhibiting increased algal growth in response to nutrient enrichment. This study evaluates primary production patterns in an estuarine system (Bass Harbor Marsh, ME, USA) receiving low levels of anthropogenic nitrogen. Biomass, areal coverage and in situ oxygen production of green macroalgae, Ruppia maritima, and phytoplankton were measured over a growing season to determine net ecosystem production. Macroalgae and R. maritima exhibited seasonal biomass curves with early summer peaks; however, peak biomass of macroalgae [150 g dry weight (wt) m-2] was substantially greater than R. maritima (33 g dry wt m-2). Phytoplankton biomass, measured as chlorophyll a, was low (<1 µg l-1) early in the season and peaked (11 µg l-1) following a mid-summer decline in macroalgal biomass, suggesting a competitive interaction with macroalgae. Instantaneous net production rates varied over the growing season for all 3 primary producers. R. maritima net production ranged from near zero to 3.7 mg C g-1 dry wt h-1, with higher rates during summer and much of the seasonal variability explained by temperature. Macroalgal (0.88 to 5.0 mg C g-1 dry wt h-1) and phytoplankton (0 to 28 mg C m-3 h-1) net production did not exhibit any clear seasonal signal. Net primary production calculated on an areal basis demonstrated macroalgae's dominance in the lower basin of Bass Harbor Marsh, with peak summer rates (400 mg C m-2 h-1) greatly exceeding maximum rates for both R. maritima (70 mg C m-2 h-1) and phytoplankton (12 mg C m-2 h-1). When compared to other New England estuarine sites with short residence times, nutrient loading and peak green macroalgal biomass in Bass Harbor Marsh are relatively low; however, the strong dominance of opportunistic green macroalgae is a pattern that is characteristic of shallow coastal systems undergoing eutrophication. Primary productivity · Eutrophication · Green macroalgae · Ruppia maritima · Phytoplankton · Estuary · Maine, USA Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 163. Publication date: March 12, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.

On line production costs monitoring in energy management systems

This paper presents a new tool for on line thermal and pumping plant production cost monitoring recently developed in the Energy Management System at the ENEL National Control Centre in Rome, Italy. Instantaneous production and marginal costs are computed at unit level by means of the active power telemeasurements received at NCC from power plants and data about cost curves and fuels actually used. Such data are further processed in order to obtain global data at area level. Computation methods, plant models and adopted criteria are described. Operational experience during more than 2 years of use, and tool applications in both on line control and off line analysis are discussed.

Doctrine and Exegesis in Biblical Latin Poetry (review)

Reviewed by: Doctrine and Exegesis in Biblical Latin Poetry Robert D. Sider Daniel J. Nodes. Doctrine and Exegesis in Biblical Latin Poetry. ARCA Classical and Medieval Texts, Papers and Monographs, 31. Leeds: The University of Leeds, Francis Cairns Ltd., 1993. Pp. x + 147. £20/$35.00. This fine book should serve to complement an earlier work published in the ARCA Library in 1985, Michael Roberts’ Biblical Epic and Rhetorical Paraphrase in Late Antiquity (reviewed in Patristics 18.2 [January 1990]: 89). Indeed, Nodes attempts to establish a locus for his work in relation to that of Roberts: where Roberts undertook to demonstrate how the structure of the biblical epics produced from the fourth to the sixth centuries could be explained by reference to the theory and practice of paraphrase in antiquity, Nodes seeks to show how the poets of the period shaped their poems to reflect answers to contemporary theological questions. Both scholars define their field carefully, and in such a way that the reader can enjoy complementary discussions of some of the same poems. Roberts chose to work on the Christian epic poems of the period—three paraphrasing the New Testament, three the Old: from the New, Juvencus’ Evangeliorum Libri IV, Sedulius’ Carmen Paschale, Arator’s De actibus apostolorum; from the Old, the Heptateuchos of the so-called Cyprianus Gallus, Claudius Marius Victorius’ Alethia, and the De spiritalis historiae gestis of Avitus, bishop of Vienne. Nodes, not confined by genre, analyzes Christian paraphrases of Genesis composed during virtually the same period, and he does so to illuminate the efforts of the “Genesis” poets to teach and to defend both the (now “orthodox”) doctrines of God and the Trinity, and also the Catholic tradition of cosmological reflection on Genesis 1–2. Thus, in addition to the poems of Cyprianus Gallus, Claudius Marius Victorius and Avitus, Nodes considers the Cento of Proba, the short Metrum in Genesim by pseudo-Hilarius, and Dracontius’ Laudes Dei. Nodes is highly systematic in his scholarship. Apart from an introduction, which sets perspective, and a brief conclusion, he divides his study into two parts: the first part (chapter two) looks for the doctrine of God in the poems, which are reviewed in the chronological order (as well as may be established) of their authors—Proba, Cyprianus, pseudo-Hilarius, Victorius, Dracontius and Avitus; chapter three considers the poets’ cosmological views in exactly the same order. Doctrines are extracted from the poems, then faithfully placed in a historical context through a brief discussion of the literary tradition, to show how far the theology of the poems accords with the tradition established by orthodox writers, and with whom and where it differs. Nodes wishes to place the doctrines in a tradition; only occasionally does he assert direct influence of a particular author upon our poets. In general Nodes finds that the poets affirm the transcendence and the benevolence of God and respect “Nicene” views on the doctrine of the Trinity. The relation of the second person of the Trinity to the Christ who appeared in history motivates perhaps the most interesting exegesis—both of the poets on Scripture and of Nodes on the poets: Nodes’ analysis reveals the poets as clearly [End Page 585] post-Nicene, having little connection to the earliest strata of Christological reflection. Thus in the poets the generation of the Son is disconnected from the work of creation, even though it is Christ who forms the man from the clay in creation; for these poets, too, the Christ who lived in our world was never “without the Father” in heaven. Among cosmological views, we are not surprised to find the poets defending the doctrine of creatio ex nihilo; they also generally follow the exegetical tradition in “understanding God’s creative act as the instantaneous production of the elements followed by a gradual appearance of individual species in a process of unfolding” (so Proba, 81). Nodes’ discussion of the poets’ cosmological views (chapter three) is perhaps more satisfying than his discussion of the doctrines of God and the Trinity (chapter two), largely because this chapter offers an analysis of entire poems or of clearly-outlined parts of a poem. Here the reader is invited not to...

Baroclinic generation of vorticity by an axisymmetric vortex in a linearly stratified fluid; in the passive limit

We evaluate analytically the baroclinically generated vorticity that is produced by a stationary axisymmetric vortex that overturns a fluid having an initial linear mean density profile. The instantaneous net production of vorticity due to a point vortex is shown to be proportional to the buoyancy time Nt, where N is the Brunt–Väisälä frequency. These results are valid only for the nondiffusive, passive limit, where the baroclinically produced vorticity is negligible and does not alter the velocity field. Corresponding results for the Taylor vortex show maximum production of vorticity away from the center but zero net production. The Oseen vortex behaves more like the point vortex. These differences appear related to the total circulation of these vortices.

ANALYSIS OF ROSE CROP PRODUCTION

Measured and simulated dry-matter production of two rose crops different in cultivar and growing conditions were compared. Differences in dry-matter production between the two crops could be explained to a large extend by differences in harvest index, leaf area index, supplementary lighting and CO2-level Annual dry-matter production was overestimated by a general greenhouse crop growth model extended with a subroutine for supplementary light (ALSIM 1.0). Summer production was largely over-estimated and winter production under-estimated. Differences between instantaneous dry-matter production as simulated and measured as harvesting is discussed dry-matter production and crop efficiency are useful characteristic to compare rose-crops as they eliminate some of the problems related to differences based on cultivar, quality of flowering stems economic parameters and light received at canopy level dry-matter production and crop efficiency can be useful tools for control of crop growth

A test of the partitioning between ClO and ClONO2 using simultaneous UARS measurements of ClO, NO2, and ClONO2

The photochemical theory of the partitioning hetween the chlorine species ClONO2 and ClO in the lower and mid stratosphere is tested for the first time using simultaneous measurements of ClO, NO2, and ClONO2. The theory suggests that over most of the day the production of ClONO2 through the three‐body reaction of ClO and NO2 is balanced by the loss of ClONO2 through photolysis. Our analysis tests this theory by utilizing simultaneous measurements of these species from instruments aboard the Upper Atmosphere Research Satellite (UARS), as well as calculations of the photolysis rate of ClONO2 and laboratory measurements of the rate constant for the reaction between ClO and NO2. Between 32 and 10 hPa (∼24 and 32 km), averaged instantaneous production and loss rates of ClONO2 agree within ∼10%. At 46 hPa (∼21 km), the agreement between averaged instantaneous production and loss of ClONO2 is poorer than at higher altitudes, but still within uncertainties. This analysis provides no evidence for any problems in our understanding of the partitioning between the chlorine species ClONO2 and ClO over the range of pressures (46 to 10 hPa) and latitudes (60°S to 60°N) considered here.

Depreciation erodes the Coase Conjecture

If a durable good monopolist produces at constant marginal costs and the good depreciates, there exists a family of Strong Markov Perfect Equilibrium (SMPE). One member of this family entails instantaneous production of the level of stock produced in a competitive equilibrium; this is consistent with the Coase Conjecture. Other SMPE in the family entail steady-state production at a stock level lower than in the competitive equilibrium. There may be a jump to these steady states, or they may be approached asymptotically. Monopoly profits are positive in these equilibria, and the Coase Conjecture fails.

Exothermicity and three-dimensional effects in unsteady propane square jets

We present results of numerical simulations of the near field of unsteady fuel jets emerging from a square nozzle into a quiescent oxidizer background with nonpremixed initial conditions. The jets studied are subsonic, compressible, and both jet and surroundings are diluted with nitrogen. The numerical model involves space/time developing jets, species-and temperature-dependent diffusive transport, and finite-rate global chemistry. The jet visualizations show distinct high-temperature regions associated with local exothermicity and convective concentration of burned gas governed by the highly three-dimensional dynamics of vortex rings and hairpin vortices. Instantaneous chemical production occurs mainly at the outer sides of the fuel jet, at the interfaces between reactants, where most of the diffusive mixing takes place for the relatively fast flows considered. Topological features of the distributions of the scalar dissipation rate are characterized mainly by sheet-like structures, first appearing as relatively simple footprint surfaces enclosing vortex rings and braid vortices, and then becoming increasingly convoluted due to the complicated vortex interactions. Significant viscous damping effects are found for the reactive jets because of exothermicity and the monotonically increasing dependence of viscosity with temperature. In contrast, for the nearly isothermal nonreactive jets, viscosity is found to have only a slightly stabilizing role in the absence of chemical reactions.

Oxygen atom concentrations and no production rates in a turbulent H2/N2 jet flame

An experimental procedure is demonstrated that allows determination of instantaneous oxygen-atom concentrations and thermal NO production rates in turbulent flames. This is accomplished without direct measurement of O atoms by laser-induced fluorescence, a technique that has been shown to be problematic. Simultaneous point measurements of temperature, the major species, OH, and NO are performed in a non-premixed turbulent jet flame of nitrogen-diluted hydrogen fuel. The O-atom concentration for each laser shot is derived from these data, based on the assumption of partial equilibrium of the reaction OH+OH=O+H2O. The derived O-atom concentration is then used with the measured N2 concentration and temperature to calculate the instantaneous thermal (zeldovich) NO production rate. The partial equilibrium assumption is shown to be appropriate in this flame for conditions relevant to thermal NO formation. The maximum conditionally averaged O-atom mole fraction is about 6.5 times the maximum value for full chemical equilibrium. The width in mixture fraction coordinates of the conditionally averaged NO production rate curve is roughly twice that calculated from adiabatic equilibrium values of temperature, [O], and N2. Experimental results are compared with predictions obtained using the Monte Carlo PDF model with detailed chemistry. With some exception, there is good agreement between experiment and prediction when results are plotted against mixture-fraction (scatter plots and conditional averages). Agreement is not as good when radial profiles of averaged scalar quantities are compared. This indicates that the present PDF model predicts the hydrogen and nitrogen chemistry with good accuracy but that improvements are needed in the modeling of the turbulent fluid dynamics and mixing. A comparison of experimental results with steady strained laminar flame calculations shows that the turbulent flame conditions cannot be represented by a combination of the laminar flames.

Evaluation of Competition and Predation as Limits to Juvenile Kokanee and Sockeye Salmon Production in Lake Ozette, Washington

We examined temporal and spatial patterns of feeding, distribution, and relative abundance of potential predators and competitors of juvenile kokanee and sockeye salmon Oncorhynchus nerka to determine which interactions might limit smolt production in Lake Ozette, Washington. Kokanee, the landlocked form of sockeye salmon, dominated the limnetic planktivore fish community, potentially creating greater intraspecific than interspecific competition. However, bioenergetic simulations and cladoceran egg-ratio analysis indicated that consumption demand by adult and juvenile kokanees and juvenile sockeye salmon could be satisfied by less than 1% of the instantaneous production of the preferred large Daphnia pulicaria throughout the growing season. Juvenile kokanees and sockeye salmon represented 72% of the annual diet by volume of large (≥300-mm fork length), limnetic northern squawfish Ptychocheilus oregonensis during winter-summer. Forty percent of the diet of large (≥300-mm fork length), limnetic cutthroat trout Oncorhynchus clarki consisted of age-0 and age- 1. O. nerka (40-140 mm fork length) during spring and summer. The per-capita predation by cutthroat trout on juvenile salmonids was 25 times greater than predation by northern squawfish. Simulations indicated that 138,900 age-0. O. nerka (17.4% of the estimated fry production) were eaten for every 1,000 large cutthroat trout in the lake, whereas only 5,600 age-0 fish (0.7% of the fry production) were eaten per 1,000 large northern squawfish. Lower predation by northern squawfish was due to the small percentages (2-8%) of these predators that inhabited the limnetic zone and interacted with age-0 and age-I O. nerka during spring and summer. We conclude that competition is unlikely to limit O. nerka production, even with an intensive enhancement program. However, predation could undermine enhancement efforts if piscivore populations are sufficiently large; therefore, piscivore abundance must be assessed before total predation losses can be estimated.

The Use of Video in ENT Endoscopy: Its Value in Teaching

Videography is the most practical and effective method of documenting and teaching ENT endoscopy. Videography allows: (1) documentation of anatomy, physiology and pathology of deep structures of the ear, nose and throat; (2) teaching of delicate surgical procedures such as functional endoscopic sinus surgery (FESS), laryngeal surgery, and other endoscopic procedures; (3) instantaneous production of high quality hard copies of video images for teaching and patient records; (4) instant replay and repeated viewing by a slow motion or frame-by-frame analysis; (5) simultaneous viewing by a small or large audience; and (6) image digitalization for storage in the computer for later analysis. The author describes the value of videography in ENT endoscopy, namely video-otoscopy, video rhinoscopy and videolaryngoscopy. The use of video in endoscopy will continue to play a vital role in Continuing Medical Education (CME).

Submerged Electric Arc Decomposition of Methanol for Cold-Starting Methanol-Fueled Engines

Methanol is an attractive alternative fuel based on its engine performance and emission characteristics. Methanol can be synthesized from biomass or urban waste, and as a result, it does not contribute to the net addition of carbon dioxide to the atmosphere. Cold-starting of methanol-fueled engines is difficult at temperatures below 10°C, and at sub-zero temperatures, starting may be impractical without significant engine modifications. In this research, an attempt has been made to study and prevent the cold-starting problem by using hydrogen and carbon monoxide gas mixture produced by decomposing liquid methanol using a submerged electric arc device. The electric arc has the advantage of instantaneous gas production and the experimental data relating to the performance of the device and its design are reported. The device is capable of producing up to 0.01 cu m (10 L) per min of a gas which is primarily carbon monoxide and hydrogen with a thermal efficiency of 18 percent relative to the theoretical energy requirements for methanol decomposition. The feasibility of using this arc device is analyzed based on the simulated cold-starting data collected for a single-cylinder Kawasaki engine at −20°C.

A mild procedure for the anomerization of 2′-deoxynucleosides

Addition of a catalyst containing sulfuric acid and acetic anhydride to a solution of 3′,5′-di- O -acetylthymidine in acetonitrile at room temperature, results in the almost instantaneous production of an equilibrium mixture of α- and β-anomers. Under certain conditions with increasing time, substantial quantities of a diasterioisomeric mixture of fully acetylated open-chain nucleosides are formed.

Irreversibility and randomness in linear response theory

Recall that the fluctuation-dissipation theorem connects the response function of a passive linear system and the spectral density of the stationary stochastic process which describes the thermal fluctuations in the system. It is shown that the classical limit (ħ=0) of the fluctuation-dissipation theorem implies a correspondence between systems which are reversible in the sense that the energy used to drive them away from equilibrium is completely recoverable as work and processes which are deterministic in the sense of Wiener's prediction theory, while irreversible systems correspond to nondeterministic processes. This correspondence is expressed by a simple transformation between the operator kernel which determines the optimal choice of the time-dependent force and the linear predictor for the stochastic process. For quantum systems this correspondence does not hold; the fluctuations are always of the deterministic type for any finite temperature, but the system is not necessarily reversible. For irreversible systems a formula is derived for the instantaneous entropy production which is a generalization of the standard one for Markovian dynamics.

Synthesis and analysis of the opioid analgesic [14C]-fentanyl

The synthesis of [14C]-fentanyl, the radiolabelled congener of the potent opioid analgesic chosen for utilization in drug disposition studies, is described. [14C]-Labelling was achieved in the first of two steps, a room temperature reduction of the in situ generated Schiff base from 1-phenylethyl-4-piperidone and [UL-14C]-aniline hydrochloride with sodium triacetoxyborohydride. A nearly instantaneous production of fentanyl was accomplished at room temperature with the addition of propionyl chloride. The overall radiochemical yield was 18%. The method described is efficiently adaptable for submicromolar scale while yielding a product of sufficient specific activity for in vivo studies. Our solvent system for thin layer chromatography was superior to the USP system reported for chromatographic analysis of fentanyl. This is the first reported preparation of [14C]-fentanyl with the radiolabel in the aniline benzene ring.

Supply function equilibria and the danger of tacit collusion: The case of spot markets for electricity

Because of the special nature of electricity (instantaneous production and consumption, quick and partly stochastic fluctuations of demand), the production decisions on a hypothetical spot market have to be automated. We model this automation by assuming that the instruments of competition are the supply functions of the producers. Three oligopoly models (games among the producers) are investigated and, in every case, a continuum of solutions is found. These solutions allow for tacit collusion among the producers. When they select the symmetric solution with the highest profits, then an increasing number of producers does not necessarily imply that the aggregate profits converge to zero. When the customers have to pay constant prices then joint profit maximization (the monopoly solution) is an equilibrium. When the consumers have to pay spot prices, with an increasing number of producers, prices converge to marginal costs. This convergence is slow, however, if the fluctuations of demand are small.

Scaling of nitric oxide emissions from buoyancy-dominated hydrocarbon turbulent-jet diffusion flames

Results of theoretical estimates and of measurements are reported on emissions of oxides of nitrogen from large methane, propane and natural-gas flames under buoyancy-controlled conditions. The theory employs reduced chemical-kinetic mechanisms for the reaction-sheet regime along with simplified mass, momentum and mixture-fraction balances for the turbulent flame height. Explicit expressions for local, instantaneous NO production rates are derived, involving rate constants of only fourteen elementary steps, and a two-reaction-zone description of the laminar flamelets is adopted, enabling average production rates to be obtained from asymptotics through approximation of a joint probability-density function for mixture fraction and scalar dissipation. The theory predicts significant contributions from the Zel'dovich mechanism in the oxygen-consumption zone and from the prompt mechanism in the fuel-consumption zone but negligible contributions from the nitrous-oxide mechanism and gives an increase in the ratio of prompt to Zel'dovich contributions with increasing strain rates, as extinction is approached. The experiments employ continuous gas analyzers with water-cooled quartz and stainless-steel suction probes and derive emission indices from measured ratios of NO x to CO 2 concentrations. The experimental results are in reasonable agreement with a Froude-number correlation derived from the theory over a range of Froude numbers from 10 to 5×10 5 , wider than available previously.