Ramp Slope Research Articles

Effect of ramp slope on the efficiency of hump weirs in free flow condition

A series of numerical simulations was performed to study the discharge capacity of symmetrical hump weirs in free flow condition. A wide range of ramp slopes was selected from 1 V:1 H to 1 V:5 H and the effects of flow discharge and ramp slope on variations of discharge coefficient were investigated. The variations of upstream water head with discharge indicated the existence of two distinct flow regimes on free flow over symmetrical hump weirs. It was found that the discharge coefficient increased with increasing the upstream water head until the maximum discharge coefficient was achieved. Further increase of water head caused a reduction in discharge coefficient and the flow regime became inefficient. The proposed models for prediction of discharge characteristics of sharp-crested weirs with an upstream and (or) downstream ramp(s) from the literature were also compared with the discharge capacity of sharp-crested weirs to study the effects of ramp slope. It was found that the available head–discharge models are acceptable for hump weirs with small ramp length and more accurate prediction models are required for symmetrical hump weirs with larger ramps. The boundary curve to determine the optimum performance in symmetrical hump weirs was introduced, and the head–discharge models for both efficient and inefficient discharge conditions were proposed.

Synthetic fuzzballs: a linear ramp from black hole normal modes

We consider a black hole with a stretched horizon as a toy model for a fuzzball microstate. The stretched horizon provides a cut-off, and therefore one can determine the normal (as opposed to quasi-normal) modes of a probe scalar in this geometry. For the BTZ black hole, we compute these as a function of the level n and the angular quantum number J. Conventional level repulsion is absent in this system, and yet we find that the Spectral Form Factor (SFF) shows clear evidence for a dip-ramp-plateau structure with a linear ramp of slope ~ 1 on a log-log plot, with or without ensemble averaging. We show that this is a robust feature of stretched horizons by repeating our calculations on the Rindler wedge (times a compact space). We also observe that this is not a generic feature of integrable systems, as illustrated by standard examples like integrable billiards and random 2-site coupled SYK model, among others. The origins of the ramp can be traced to the hierarchically weaker dependence of the normal mode spectrum on the quantum numbers of the compact directions, and the resulting quasi-degeneracy. We conclude by noting an analogy between the 4-site coupled SYK model and the quartic coupling responsible for the non-linear instability of capped geometries. Based on this, we speculate that incorporating probe self-interactions will lead to stronger connections to random matrix behavior.

Features of the sedimentation, stratigraphy and carbon isotope record of the upper Tournaisian of the Verkhnyaya Usa depression (Polar Urals)

Research subject. Upper Tournaisian clayey-siliceous-carbonate deposits of the Malaya Usa section (Polar Urals).Material and methods. The composition and structure of the deposits (50 samples, 51 thin sections) of the section were considered to determine the conditions of sedimentation; 13 samples were chemically disintegrated in 7–10% solution of acetic acid, and thin sections were studied for biostratigraphic analysis (conodonts, ostracods, and foraminifers); the carbon and oxygen isotopic composition of carbonate deposits (49 samples) were analyzed. A three-stage screening test of samples for isotopic-studies was carried out.Results. The Malaya Usa section comprises mainly micritic limestones with fossils silicified to various degree (wackstone to packstone). The features and composition of the sediments indicate sedimentation in low dynamic conditions below the wave base. Biostratigraphic analysis is based on the identification of foraminifers, as well as a few conodonts and ostracods. Foraminifers characterize the Eotextularia diversa–Dainella chomatica Zone, which is approximately comparable to the Upper typicus–anchoralis–latus conodont zonal interval and Entomoprimitia malinovkaensis‑Marginia tschigovae ostracode zones of the top of the Tournaisian. The isotope-geochemical data obtained from the section demonstrate a general lightening trend in the isotopic composition of δ13Ccarb up the section. This trend, along with the biostratigraphic data, mades it possible to compare the δ13Ccarb sequence of the Malaya Usa section with sequences from a number of geographically separated sections of the world (Belgium, South China, USA), which are considered as the Tournaisian isotope carbon event (TICE).Conclusions. The deposits of the studied section were probably formed under the conditions of a very gentle slope (ramp), where the material accumulated at the foot as a filling sequence in the southern part of the Korotaikha intrashelf paleodepression. Using the Malaya Usa section as an example, it is shown that not only the peak positive deviations of the TICE in the upper part of the isosticha Zone and in the lower part of the typicus Zone, but also the isotopic structure of the upper Tournaisian has a significant correlation potential. The use of the isotope-geochemical method as an auxiliary application to biostratigraphy made it possible to improve the age determination of the section from the interval of the Upper typicus–anchoralis–latus conodont zonal interval to the Upper typicus Zone of the standard conodont zonation.

Effects of upstream and downstream ramp on flow characteristics over a cylindrical weir

Cylindrical weirs are one of the most commonly employed hydraulic structures to measure flow, compare to other types of the same width they pass larger discharge. This paper presents an experimental work together with a CFD simulation to study the effects of the geometric characteristics of a cylindrical weir and a ramp placed upstream or downstream of the same weir on the discharge coefficient. Three different weir diameters and three ramp angles under three different discharges were utilized. The results show that the geometric characteristics represented by the diameter of the weir affects the discharge coefficient when there is no ramp. The discharge coefficient was observed to decrease as the slope of the upstream ramp was increased, however as the slope of the downstream ramp was increased the discharge coefficient was noted to increase. A mathematical relationship was developed in order to calculate the discharge of flow passes over the cylindrical weir depending on its diameter.

The spectral form factor in the 't Hooft limit – Intermediacy versus universality

The Spectral Form Factor (SFF) is a convenient tool for the characterization of eigenvalue statistics of systems with discrete spectra, and thus serves as a proxy for quantum chaoticity. This work presents an analytical calculation of the SFF of the Chern-Simons Matrix Model (CSMM), which was first introduced to describe the intermediate level statistics of disordered electrons at the mobility edge . The CSMM is characterized by a parameter 0\leq q\leq 1 0≤q≤1, where the Circular Unitary Ensemble (CUE) is recovered for q\to 0 q→0. The CSMM was later found as a matrix model description of U(N) U(N) Chern-Simons theory on S^3 S3 , which is dual to a topological string theory characterized by string coupling g_s=-\log q gs=−logq. The spectral form factor is proportional to a colored HOMFLY invariant of a (2n,2) (2n,2)-torus link with its two components carrying the fundamental and antifundamental representations, respectively. We check explicitly that taking N \to \infty N→∞ whilst keeping q<1 q<1 reduces the connected SFF to an exact linear ramp of unit slope, thereby confirming the main result from for the specific case of the CSMM. We then consider the ’t Hooft limit, where N \to \infty N→∞ and q \to 1^- q→1− such that y=q^N y=qN remains finite. As we take q\to 1^- q→1−, this constitutes the opposite extreme of the CUE limit. In the 't Hooft limit, the connected SFF turns into a remarkable sequence of polynomials which, as far as the authors are aware, have not appeared in the literature thus far. A gap opens in the spectrum and, after unfolding by a constant rescaling, the connected SFF approximates a linear ramp of unit slope for all y y except y \approx 1 y≈1, where the connected SFF goes to zero. We thus find that, although the CSMM was introduced to describe intermediate statistics and the 't Hooft limit is the opposite limit of the CUE, we still recover Wigner-Dyson universality for all y y except y\approx 1 y≈1.

Experimental analysis of the effect of the ramp slopes on the maximum exceedance temperature in a branched tunnel fire

This research aims to establish a series of small-scale experiments to analyze the effect of ramp slopes on the temperature distribution of Liquefied Petroleum Gas (LPG) fire in a model branched tunnel under longitudinal ventilation. The heat release rate under experimental conditions reached 2.57 kW to 7.70 kW and five ramp slopes of 0 %, 3 %, 5 %, 7 % and 9 % were conducted. For a specific given bifurcation angle, the maximum exceedance temperature of the fire in the expanding region before the bifurcation angle is measured and analysed. Results show that the maximum exceedance temperature in the main tunnel increases as the ramp slope decreases, which is mainly because the stack effect enhances the entrainment of the air and accelerates the smoke flow. Furthermore, the modified model of the maximum exceedance temperature, which could consider the influence of ramp slope for a branch tunnel fire is established according to the experimental results. The predicted results agree well with those of the experimental study for the main tunnel. The results could provide a reference and contribute to the knowledge of smoke extraction strategies designed for branched tunnels.

Improving the built environment for manual wheelchair users: A review

The aim of Universal Design is to make the built environment accessible to all people regardless of disability. This is a laudable aim, but most people are unaware of the many barriers manual wheelchair users actually face when accessing the built environment. The main challenges for manual wheelchair users arise from three areas. Firstly, there are intrinsic limitations arising from the manual wheelchair user’s condition and capability. Secondly, there are features such as ramps and cross slopes in the built environment that fail to comply with building codes relating to wheelchair access. Thirdly, there are cosmetic features such as cracked paths, obstructions and poorly placed signage that place an additional burden on manual wheelchair navigation. Each of these three areas is discussed in this article.The intrinsic limitations of user condition and capability include a wide range of physical impairments and an inherently inefficient manual wheelchair propulsion mechanism. The typical code compliance requirements for wheelchair access in the built environment range from limitations on minimum path widths to maximum permissible ramp slopes. However, even when these features comply with code requirements they may be compromised by temporary obstructions or by poor maintenance so that they become insurmountable challenges to manual wheelchair users. An understanding of these challenges is necessary to improve the built environment so that it is more accessible to manual wheelchair users in the future.

Usability Evaluation of Access Ramps in Transit Buses: Preliminary Findings

The research literature on access ramps used in transit vehicles is undermined by inconsistent methodologies used across studies, thus providing an inconclusive evidence base for proposed Federal guidelines that would impose a maximum 1:6 slope for all deployment situations. The current study assessed the usability of ramp slope for mobility aid users. Four access ramp slopes were evaluated, with 27 adults representing three populations: manual wheelchair users, power wheelchair users, and people with vision impairment who use a cane or service animal. The dependent variables included five usability measures. The 1:8 and 1:12 slopes were usable and acceptable for most participants. The data indicate that the 1:4 slope is too steep for safe unassisted boarding and disembarking. Many manual wheelchair users lacked the strength needed for unassisted ascent. Power wheelchair users and people with vision impairment expressed safety concerns about descent of steeper slopes. Conclusive interpretations should be cautiously drawn because the sample size was relatively small and did not include users of scooters or ambulation aids.

Ingress/Egress Incidents Involving Wheelchair Users in a Fixed-Route Public Transit Environment

The objectives of this study were to characterize the ingress and egress activities of wheeled mobility device (WhMD) passengers using fixed-route large, accessible transit vehicles (LATVs), and to examine factors associated with incidents occurring on ramps. A retrospective review of public transit video surveillance footage of WhMD-seated passengers accessing fixed-route LATVs was conducted. Ingress and egress activities were characterized based on travel conditions and characteristics of the WhMD and LATV ramp. Incidents were identified based on predetermined criteria, and chi-square analysis was performed to identify WhMD and/or ingress/egress characteristics associated with incidents. Video records of 250 WhMD trips were analyzed. A total of 39 incidents occurred during ingress and 12 incidents occurred during egress. Results indicated that the frequency of incidents was significantly greater for scooter users and passengers who ascended the ramp using a rear-facing WhMD orientation. Narrow LATV ramp width was associated with the greatest number of incidents, followed by problems related to LATV door width and steep ramp slope.

Testing sea-level and carbonate production effects on stratal architecture of a distally steepened carbonate ramp (Upper Miocene, Menorca): A 3D forward modelling approach

Although distally steepened carbonate ramps have been studied by numerous researchers, the processes that control the development of these carbonate systems, including tectonics, differential carbonate production along the ramp profile, or antecedent physiography of the slopes, are an ongoing discussion. We use a stratigraphic forward model to test different hypotheses to unravel controls over distally steepened ramp development, referenced to the well-known Upper Miocene Menorca carbonate ramp (Spain). Sensitivity tests show that distally steepened ramps develop under complex interaction among accommodation, carbonate production and sediment transport parameters. Ramp slope initiation is favoured by still stands and falls of sea-level, in a setting with high-frequency sea-level fluctuations with amplitude between 20 m and 40 m. Low-frequency and higher amplitude sea-level fluctuations of about 115 m tend to form models with no significant slope development. The impact of antecedent slope on the geometry of ramps is determined by the paleoslope inclination, with flat to subhorizontal paleosurfaces resulting in ramps that mirror the antecedent slope. In contrast, steeper paleosurfaces tend to result in ramps with well-defined slopes. Our models, therefore, show that the ramp profile becomes more influenced by the depth constraints on the carbonate sediment producers than by the geometry of the underlying topography as the inclination of the paleosurface increases. The presented models also show that seagrass-dominated shallow carbonate production tends to result in steep slopes due to the low-transport characteristic imposed by seagrass trapping. This steepness can, however, be altered by the introduction of high transport sediment grains from deeper carbonate producers, which fill the slopes and more distal sections of the ramp profile.

Value of cardiopulmonary exercise test submaximal parameters in the assessment of aortic stenosis patients

Abstract Background Exercise test is recommended for risk stratification of asymptomatic patients with severe aortic stenosis (AS), although a significant number of patients can't perform a maximal exercise test, increasing the potential value of sub-maximal parameters for the assessment of these patients. Aim To assess which parameters could be useful for risk stratification in case of a submaximal Cardiopulmonary Exercise Testing (CPET) in asymptomatic patients with severe AS. Methods Retrospective evaluation of adult patients with asymptomatic severe AS, in a single center, who underwent CPET between December 2016 and November 2021. All patients underwent a treadmill CPET using an exercise protocol with progressive increase in workload. Patients were divided in group A (maximal CPET) or group B, respectively, if respiratory exchange ratio (RER) was >1.10 at peak exercise or below this value. Known parameters accessed in a submaximal CPET were evaluated: mean minute ventilation/carbon dioxide production slope (VE/VCO2), VO2 value in first ventilatory threshold (VT1), peak circulatory power, and oxygen uptake efficiency slope (OUES). Results CPET was performed in 25 patients with severe asymptomatic AS (80 years ± 7 years, 56% male), median AVA was 0.86 cm2 [IQR 0.65–0.95 cm2] and transaortic pressure gradient was 46 mmHg [IQR 41–55 mmHg]. The most used protocol was a ramp slope. Nineteen patients (76%) didn't reach a RER>1.10 (group B) due to respiratory (26%) or peripheral limitation (53%). Comparing both groups, group B patients showed a shorter duration of exercise of (8±3 min vs. 9±4 min, p=0.422), and a lowest mean peak VO2 (16.3±3.6 vs. 20.5±6.9 ml/kg/min, p=0.207). In our population, bivariate analyses demonstrated that OUES was the only submaximal parameter that could discriminate both groups: Group B patients had the lowest values (1.53 [IQR 1.47–1.70] vs. 1.94 [IQR 1.56–2.11], p=0.042). ROC curve analysis of OUES values revealed an AUC of 0.78 (p=0.042) for maximal CPET prediction. The cut-off point with most sensitivity (S) and specificity (E) obtained using the Youden index (0.62) was 1.9 (S≈67%; E≈95%) (Figure 1). Conclusions In our cohort of asymptomatic AS patients, even with submaximal CPET, OUES accurately identify patients with higher degrees of functional limitation. Whether OUES is useful as prognostic marker to the workflow treatment of AS it's worth to be assessed prospectively. Funding Acknowledgement Type of funding sources: None.

Laguerre–Gaussian laser beam guiding and its second harmonics in plasma having density ramp

This paper presents the optical guiding of a laser beam in plasma by using a preformed plasma channel. The density ramp in plasma density due to the plasma pressure has also been considered. The effect of ponderomotive force has been taken into account which originates due to the intensity gradient present in the laser beam. This force produces a plasma gradient by expelling plasma electrons from a high-field to a low-field region, providing heavy ions remain immobile. Plasma oscillations result from a gradient in plasma density that excites an electron plasma wave. The equation governing the plasma wave excitation has been found by using linear perturbation theory. An in-phase mixing of an incident laser beam with this plasma wave generates its second harmonics. Laguerre–Gaussian laser profile has been used for harmonic production. Moment theory has been used to obtain a differential equation for beam waist, which has been solved numerically by Runge–Kutta's fourth-order method. The effect of different modes of Laguerre–Gaussian profile, beam intensity, plasma density, channel depth, and slope of density ramp has been explored.

Flow over embankment gabion weirs in free flow conditions

In this study, a series of laboratory tests were performed to investigate the effects of side ramp slope, crest length, and porous media properties on the flow regimes, water-surface profiles, discharge coefficients, and energy dissipation in embankment gabion weirs with upstream and downstream slopes. 24 physical models of solid and gabion weirs with three different upstream/downstream slopes (90°, 45° and 26.5°) were created. To investigate the complexity of flow over the porous-fluid interface and through the porous material, three-dimensional (3D) numerical simulations were developed. In numerical simulation, the standard k-ε turbulence model was utilized. A structured mesh domain was used to simulate the physical model. Water surface profiles above the porous weirs were used for comparison between the numerical simulations and measured data. These comparisons helped determine variables in the numerical simulations. Numerical simulation enables visualization of streamlines around and through the gabion weirs. In addition, mean stream wise velocity profiles above and within the porous structures were obtained. Numerical simulations showed that a reduction in the slope of the upstream face leads to an increased curvature of streamlines and the velocity distribution exhibits a non-uniform wavy shape due to the geometrical properties of the weirs. As the velocity profiles move downstream, the velocity distribution within the porous structures were more affected by the presence of the pores. The experimental results show that decreasing upstream slopes, from 90° to 26.5°, leads to decreased discharge coefficients. However, in all cases, gabion weirs lead to greater discharge coefficients than those of similar solid weirs. For milder side slopes, discharge ratios (flow passing through all faces of the gabion weirs over the inlet discharge) decreased nonlinearly. Moreover, with increasing the inlet discharge, relative energy dissipation was reduced up to 45% in gabion weirs.

Drift Rejection Differential Frontend for Single Plate Capacitive Sensors

Capacitive sensing at long ranges (10x the plate diameter) for long-term environmental monitoring can be limited by slow but significant measurement drifts from charge induction, which can exceed the small capacitance variations of interest, below 0.01%. This paper proposes a slope modulation differential capacitance measurement method for single-plate capacitive sensors operating in loading mode that effectively rejects noise from quasi-constant drift currents. It is based on periodical plate capacitance charge-discharge, like the period modulation frontends (astable multivibrators) that were used in past work, but it uses a constant oscillation period and compares the slopes of adjacent plate voltage ramps. Plate capacitance is calculated by averaging the slope magnitudes, which rejects the noise from quasi-constant drift currents. The sensitivity and noise rejection are compared with the period modulation techniques analytically, and the results are validated using simulations and experiments. They show that human body sensing range doubles and the noise floor is substantially lower compared to the state-of-the-art (period modulation).

Flow through a sluice gate over a broad crested weir under free- and submerged-flow conditions

ABSTRACT This paper describes the hydraulic characteristics of flow through a sluice gate over a broad-crested weir with a fixed upstream ramp slope of 1:2 and downstream ramp slopes of 1:2, 1:3, and 1:4. A relationship was proposed to determine the contraction coefficient of the flow passing through the gate, under free-flow conditions, in which the average value was 0.71 for all observed data. The developed relationship was used to calculate the head-loss coefficient from the studied structures under free-flow conditions, which averaged 0.31. The value of the mean absolute relative error for the proposed relationship to estimate the discharge coefficient under free-flow conditions was 1.7%. Examination of the different downstream slopes on the discharge coefficient under free-flow conditions showed that a downstream ramp slope of 1:3 is most appropriate when compared to the results for the other slopes. The value of the mean absolute relative error of the developed relationship to estimate the discharge coefficient under submerged flow conditions was 5.7%, while its corresponding value from the WinGate software was 13.1%. A survey of the effect of downstream ramp slope on the depth of submergence threshold showed that an increase in the downstream slope tends to increase the depth of the submergence threshold, whereby its value under low slopes was not significant.

Effect of large scale roughness of block ramps on dissolved oxygen efficiency in water

Abstract Block ramps are generally characterized by super critical flow over the ramps, and the presence of roughness lying on the surface of the block ramps induces excessive turbulence, which causes some turbulent energy dissipation and air entrainment. Aeration in a block ramp is caused by the intensity of turbulence created in the water flow by surface roughness of the block ramp and hydraulic jump downstream of block ramp. Macro or large-scale roughness like boulders, as a protruding element on surface of block ramp, could increase intensify turbulence and flow aeration along block ramps. This paper presents an experimental investigation of the dissolved oxygen efficiency in block ramps with slopes of 1:3, 1:5 and 1:7, on which large-scale granular materials with different arrangement patterns were glued. Comparison of results indicated that, for both free and ramp hydraulic jumps, the block ramps with a slope of 1:3 and large-scale roughness increase the dissolved oxygen efficiency almost 20% above that of the similar smooth block ramps. By reducing of the slope of block ramps to 1:5, the dissolved oxygen efficiency of the block ramps with large surface roughness became 3 and 19% for free and ramp hydraulic jumps, respectively. However, the block ramps with 1:7 slope had corresponding dissolved oxygen efficiency of 19 and 32%, respectively. Furthermore, installation of large scale roughness with the structured arrangement have better performance to increase dissolved oxygen (DO) in comparison with the interlocked large-scale roughness.

Sequence stratigraphy of a southern Paleotethys distally-steepened ramp during the Early Carboniferous (Alborz Basin, Iran): Deciphering Tectonic and Eustatic controls

ABSTRACT The Lower Carboniferous carbonate sediments of the Mobarak Formation have been analysed to evaluate the role of allogenic and autogenic factors on the development of a distally steepened carbonate platform. Thirteen facies are identified in the studied succession and are grouped into four facies associations: inner ramp FA‒FB; middle ramp FC; ramp slope FD; and deep ramp FE. The rifting event at the northern margin of the Gondwana supercontinent caused a remarkable change in the depositional system so that the precursor homoclinal ramp (Khosheilagh Formation, Devonian) turned into the distally steepened ramp of the Mobarak Formation. Six depositional sequences are identified in the succession, characterized by varieties the normal transgression‒regression cycles, the TST‒HST, or the transgression‒forced regression cycles consisting of the TST‒HST‒FSST. The main controlling elements in the stacking pattern of sedimentary packages, relative sea-level changes and the formation of depositional sequences were tectonic activity and eustatic sea-level changes. Development of the FSST package was caused by the increasing tectonic activity and the formation of turbiditic sediments, amplified by wave-induced currents as the autogenic factor on formation of the re-sedimented deposits. Development of the HST deposits displays a relative balance between sedimentation rate and the creation of accommodation space. Thick packages of deep ramp calcareous shale were developed during quiescence in the tectonic activity and increase in accommodation space, created by thermal subsidence and rise in eustatic sea-level.

Unraveling flow hydraulics for intermediate roughness conditions in sediment motion over loose block ramps

ABSTRACT The block ramps are characterized by large randomly dumped macro-rugged elements on the riverbed, which are aquatic-friendly river restoration structures used for stabilizing riverbed. A special case of loose block ramp (LBR) with varying slopes of (S = 0.1, 0.15, and 0.2) is considered to investigate the ramp stability and the ramp behavior in intermediate roughness conditions. Erosion of ramp material may affect the stability of the LBR, which may in turn leads to significant damages. The present paper addresses the factors that affect the flow resistance, relative submergence, and intensity of block movement for various flow regimes. It was found that the critical Shield’s stress increases with ramp slope, and the intensity of ramp motion is also expected to increase with the shear stress. The results indicated that friction resistance increases with relative submergence for the tested range of experiments. A comparison with several model predictions with uniform sediment transport indicates that relative roughness of block is responsible for increasing the critical Shield’s stress in the present experimental study.

Bolide impact effects on the West Florida Platform, Gulf of Mexico: End Cretaceous and late Eocene

Abstract This study documents seismic reflection evidence that two different bolide impacts significantly disrupted stratigraphic and depositional processes on the West Florida Platform (Gulf of Mexico). The first impact terminated the Late Cretaceous Epoch (Chicxulub impact, Mexico; ca. 66 Ma; end-Maastrichtian age). The second took place in the late Eocene (Chesapeake Bay impact, Virginia, USA, portion of the Chesapeake Bay; ca. 35 Ma; Priabonian age). Both impacts produced far-reaching seismic shaking and ground roll followed by an impact-generated tsunami, the effects of which are evident in the seismostratigraphic record. The Chicxulub seismic shaking caused collapse and shoreward retreat of the Florida Escarpment and widely disrupted (faulting, folding, slumping) normal flat-lying shelf beds. The associated tsunami currents redistributed these shelf deposits and mixed them together with collapse debris from the escarpment to form a thick wedge of sediments along the base of the escarpment. The Chesapeake Bay impact created a mounded sedimentary deposit near the outer edge of the late Eocene ramp slope. This deposit also has a bipartite origin. A lower layer is marked by en echelon faulting created in situ by seismic shaking, whereas an upper layer represents sediments redistributed from the late Eocene shelf and upper ramp slope by tsunami-driven bottom currents (debris flows, contour currents, slumps). This is the first report of seismic effects from the Chesapeake Bay impact in the Gulf of Mexico. These results further demonstrate that large-scale marine bolide impacts have widespread effects on the stratigraphic and depositional record of Earth.

Effect of Ramp Slope on the Efficiency of Symmetrical Hump Weirs in Free Flow Condition

Effect of Ramp Slope on the Efficiency of Symmetrical Hump Weirs in Free Flow Condition