scholarly journals Oblique sand ridges in confined tidal channels due to Coriolis and frictional torques

2020 ◽  
Vol 70 (12) ◽  
pp. 1505-1513
Author(s):  
Tjebbe M. Hepkema ◽  
Huib E. de Swart ◽  
Abdel Nnafie ◽  
George P. Schramkowski ◽  
Henk M. Schuttelaars
Keyword(s):  
Continental Shelf ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Coriolis Effect ◽  
Tidal Channel ◽  
Tidal Channels ◽  
Initial Formation ◽  
Sand Ridges ◽  
Tidal Sand

AbstractThe role of the Coriolis effect in the initial formation of bottom patterns in a tidal channel is studied by means of a linear stability analysis. The key finding is that the mechanism generating oblique tidal sand ridges on the continental shelf is also present in confined tidal channels. As a result, the Coriolis effect causes the fastest growing pattern to be a combination of tidal bars and oblique tidal sand ridges. Similar as on the continental shelf, the Coriolis-induced torques cause anticyclonic residual circulations around the ridges, which lead to the accumulation of sand above the ridges. Furthermore, an asymptotic analysis indicates that the maximum growth rate of the bottom perturbation is slightly increased by the Coriolis effect, while its preferred wavelength is hardly influenced.

Updraft/Downdraft Constraints for Moist Baroclinic Modes and Their Implications for the Short-Wave Cutoff and Maximum Growth Rate

2005 ◽  
Vol 62 (12) ◽  
pp. 4450-4458 ◽  
Author(s):  
Pablo Zurita-Gotor
Keyword(s):  
Growth Rate ◽  
Vertical Structure ◽  
Baroclinic Instability ◽  
Maximum Growth ◽  
Static Stability ◽  
Short Wave ◽  
Maximum Growth Rate ◽  
Unstable Solutions ◽  
Baroclinic Modes

Abstract This paper examines the dynamics of moist baroclinic modes, based on the idealized model of moist baroclinic instability devised by Emanuel et al. These authors found that the finite static stability along the downdraft prevents the explosive short-wave cyclogenesis of the zero stratification limit in the moist problem, and allows only moderate (order 2) changes in the growth rate and short-wave cutoff, even when the moist static stability vanishes. To understand the limiting role of the dry static stability, a constraint is derived in this paper that relates the updraft and downdraft structures. This constraint is based on continuity and implies that a bulk wavenumber (defined in the paper) scales as the relevant deformation radius in each region. Because neutral solutions are separable, the vertical structure can be encapsulated in terms of a single, equivalent wavenumber based on the downdraft width. This allows an interpretation of the results in terms of the equivalent dry mode. As the ratio between moist and dry static stability decreases, the downdraft width takes an increasingly larger fraction of the total wavelength. In the limit of moist neutrality all the wavelength is occupied by the downdraft, so that the short-wave cutoff is halved. The vertical phase tilt makes unstable solutions nonseparable, and prevents defining an equivalent wavenumber in that case. However, the constraint between the bulk wavenumbers still applies. As the moist stability is reduced, the updraft solution becomes more suboptimal; in the limit of moist neutrality, the updraft wavenumber equals the short-wave cutoff. This provides a bound to the maximum growth rate in the moist problem, which is in agreement with the results of Emanuel et al.

scholarly journals FASIES DAN LINGKUNGAN PENGENDAPAN FORMASI KANIKEH, CEKUNGAN BULA, MALUKU

2020 ◽  
Vol 30 (2) ◽  
pp. 171
Author(s):  
Akhmad Khahlil Gibran ◽  
Aries Kusworo
Keyword(s):  
Source Rock ◽  
Depositional Environment ◽  
Stratigraphic Correlation ◽  
Tidal Channel ◽  
Tidal Channels ◽  
Sand Flat ◽  
Facies Associations ◽  
Tidal Sand ◽  
Siliciclastic Rocks ◽  
Excellent Source

Batuan silisiklastik berumur Trias yaitu Formasi Kanikeh, tersebar di Pulau Seram hingga Pulau Kesui dan Teor dari Maluku hingga Maluku Tenggara. Formasi Kanikeh telah lama dikenal memiliki karakteristik batuan induk yang baik. Pemahaman tentang Formasi Kanikeh masih minim, interpretasi lingkungan pengendapan dan korelasi stratigrafi masih ada perbedaan. Tujuan penelitian ini adalah mendapatkan hasil interpretasi lingkungan pengendapan berdasarkan data terbaru. Metode yang digunakan dalam penelitian ini adalah pengukuran penampang stratigrafi pada empat lintasan pengamatan di daerah Seram Bagian Timur dengan menggunakan pendekatan analisis litofasies dan asosiasi fasies. Hasil dari penelitian ini menunjukkan adanya 9 litofasies, yaitu: Litofasies Batupasir Konglomeratan (Sg); Litofasies Batupasir Lapisan Silangsiur Mangkok (Sp); Litofasies Batupasir Bioturbasi (Sb); Litofasies Batupasir Karbonan (Sc); Litofasies Batupasir Bergelombang (Sw); Litofasies Batupasir Flasser (Sf); Litofasies Batupasir Laminasi Sejajar (Sh); Litofasies Batulumpur Lenticular (Fl); Litofasies Batulumpur Berlapis (Fsc). Deskripsi litofasies tersebut termasuk ke dalam suatu sistem pengendapan pasang-surut (intertidal) yaitu tidal channel, tidal sand flat, tidal sand-mud mixed flat, dan tidal mudflat. Formasi Kanikeh terendapkan dengan sistem pengendapan batuan silisiklastik yang dipengaruhi oleh arus pasang-surut pada lingkungan pengendapan transisi. ABSTRACT - Facies and depositional environment of Kanikeh Formation, Bula Basin, Maluku. The Triassic siliciclastic rocks, Kanikeh Formation are spread across Seram, Kesui, and Teor Island from Molucca to Southeast Molucca. The Kanikeh formation has been known as an excellent source rock. However, its interpretation of the depositional environment and stratigraphic correlation are still poorly understood. This study aims to give a better understanding of the depositional environment. This study consists of Lithofacies descriptions and facies associations of four stratigraphy measuring sections in Eastern Seram Island. The results of this study indicate that there are 9 lithofacies, including conglomeratic sandstone (Sc); Through cross bed sandstone (Sp); Bioturbated sandstone (Sb); Carboniferous sandstone (Sc); Wavy Sandstone (Sw); Flasser Sandstone (Sf); parallel laminated sandstone (Sh); lenticular mudstone (Fl); dan laminated mudstone (Fsc). The lithofacies description is included in four facies associations which are included in a tidal deposition system (intertidal) there are tidal channels, tidal sand flat, tidal sand-mud mixed flat, dan tidal mudflat. Based on the results Kanikeh Formation is deposited with a siliciclastic deposition system influenced by tidal currents within transition deposition environments.

scholarly journals Optimizing of Microalgae Scenedesmus sp. Biomass Production in Wet Market Wastewater Using Response Surface Methodology

2021 ◽  
Vol 13 (4) ◽  
pp. 2216
Author(s):  
Najeeha Mohd Apandi ◽  
Mimi Suliza Muhamad ◽  
Radin Maya Saphira Radin Mohamed ◽  
Norshuhaila Mohamed Sunar ◽  
Adel Al-Gheethi ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Biomass Yield ◽  
Biomass Productivity ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Aeration Rate ◽  
Composition Analysis ◽  
Wet Market ◽  
Central Composite

The present study aimed to optimize the production of Scenedesmus sp. biomass during the phycoremediation process. The biomass productivity was optimized using face centred central composite design (FCCCD) in response surface methodology (RSM) as a function of two independent variables that included wet market wastewater concentrations (A) with a range of 10% to 75% and aeration rate (B) with a range of 0.02 to 4.0 L/min. The results revealed that the highest biomass productivity (73 mg/L/d) and maximum growth rate (1.19 day−1) was achieved with the 64.26% of (A) and 3.08 L/min of (B). The GC-MS composition analysis of the biomass yield extract revealed that the major compounds are hexadecane (25%), glaucine (16.2%), and phytol (8.33%). The presence of these compounds suggests that WMW has the potential to be used as a production medium for Scenedesmus sp. Biomass, which has several applications in the pharmaceutical and chemical industry.

A note on growth curves of rabbit lines selected on growth rate or litter size

1993 ◽  
Vol 57 (2) ◽  
pp. 332-334 ◽  
Author(s):  
A. Blasco ◽  
E. Gómez
Keyword(s):  
Growth Rate ◽  
Litter Size ◽  
Growth Curves ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Standard Errors ◽  
Adult Weight ◽  
Weight Growth ◽  
Using Data

Two synthetic lines of rabbits were used in the experiment. Line V, selected on litter size, and line R, selected on growth rate. Ninety-six animals were randomly collected from 48 litters, taking a male and a female each time. Richards and Gompertz growth curves were fitted. Sexual dimorphism appeared in the line V but not in the R. Values for b and k were similar in all curves. Maximum growth rate took place in weeks 7 to 8. A break due to weaning could be observed in weeks 4 to 5. Although there is a remarkable similarity of the values of all the parameters using data from the first 20 weeks only, the higher standard errors on adult weight would make 30 weeks the preferable time to take data for live-weight growth curves.

Formation, evolution and present-day activity of offshore sand ridges on a narrow, tideless continental shelf with limited sediment supply

2018 ◽  
Vol 397 ◽  
pp. 93-107 ◽  
Author(s):  
R. Durán ◽  
J. Guillén ◽  
J. Rivera ◽  
F.J. Lobo ◽  
A. Muñoz ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Sediment Supply ◽  
Sand Ridges

Reassessment of Maximum Growth Rates for C3 and C4 Crops

1978 ◽  
Vol 14 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. L. Monteith
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growing Season ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Crop Growth ◽  
Close Inspection ◽  
Similar Difference ◽  
Photosynthetic Efficiencies

SUMMARYFigures for maximum crop growth rates, reviewed by Gifford (1974), suggest that the productivity of C3 and C4 species is almost indistinguishable. However, close inspection of these figures at source and correspondence with several authors revealed a number of errors. When all unreliable figures were discarded, the maximum growth rate for C3 stands fell in the range 34–39 g m−2 d−1 compared with 50–54 g m−2 d−1 for C4 stands. Maximum growth rates averaged over the whole growing season showed a similar difference: 13 g m−2 d−1 for C3 and 22 g m−2 d−1 for C4. These figures correspond to photosynthetic efficiencies of approximately 1·4 and 2·0%.

Vortex evolution in a round jet

1968 ◽  
Vol 31 (3) ◽  
pp. 435-448 ◽  
Author(s):  
H. A. Becker ◽  
T. A. Massaro
Keyword(s):  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Ring Vortex ◽  
Acoustic Excitation ◽  
Light Scatter ◽  
Turbulent Eddies ◽  
Cylindrical Vortex ◽  
Highly Sensitive ◽  
Pure Tones ◽  
Axisymmetrical Jet

A study has been made of the varicose instability of an axisymmetrical jet with a velocity distribution radially uniform at the nozzle mouth except for a laminar boundary layer at the wall. The evolutionary phenomena of instability, such as the rolling up of the cylindrical vortex layer into ring vortices, the coalescence of ring vortex pairs, and the eventual disintegration into turbulent eddies, have been investigated as a function of the Reynolds number using smoke photography, stroboscopic observation, and the light-scatter technique.Emphasis has been placed on the wavelength with maximum growth rate. The jet is highly sensitive to sound and the effects of several types of acoustic excitation, including pure tones, have been determined.

Plasma instabilities driven by pickup ions of ring-beam velocity distributions in the outer heliosheath 

2021 ◽  
Author(s):  
Ameneh Mousavi ◽  
Kaijun Liu ◽  
Sina Sadeghzadeh
Keyword(s):  
Magnetic Field ◽  
Maximum Growth ◽  
Dispersion Analysis ◽  
Maximum Growth Rate ◽  
Injection Velocity ◽  
Plasma Instabilities ◽  
Pickup Ions ◽  
Beam Velocity ◽  
Background Magnetic Field ◽  
Hybrid Simulations

<p><span>The stability of the pickup ions in the outer heliosheath has been studied by many researchers because of its relevance to the energetic neutral atom (ENA) ribbon observed by the Interstellar Boundary EXplorer. However, previous studies are primarily limited to pickup ions of near </span><span>90° </span><span>pickup angles, the angle between the pickup ion injection velocity and the background, local interstellar magnetic field. Investigations on pickup ions of smaller pickup angles are still lacking. In this paper, linear kinetic dispersion analysis and hybrid simulations are carried out to examine the plasma instabilities driven by pickup ions of ring-beam velocity distributions at various pickup angles between zero and </span><span>90°</span><span>. </span><span>Parallel propagating waves are studied in the parameter regime where the parallel thermal spread of the pickup ions falls into the Alfvén cyclotron stability gap. </span><span>The linear analysis results and hybrid simulations both show that the fastest growing modes are the right-hand helicity waves propagating in the direction of the background magnetic field, and the maximum growth rate occurs at the pickup angle of </span><span>82°</span><span>. The simulation results further reveal that the saturation level of the fluctuating magnetic fields for pickup angles below </span><span>45° </span><span>is higher than that for pickup angles above </span><span>45°</span><span>. So, the scattering of pickup ions at near zero pickup angles is likely more pronounced than that at near </span><span>90° </span><span>pickup angles</span> .</p>

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