A comparison of one-dimensional methods for estimating discharge capacity of straight compound channels

2004 ◽  
Vol 31 (4) ◽  
pp. 619-631 ◽  
Author(s):  
Galip Seckin
Keyword(s):  
Discharge Capacity ◽  
Single Channel ◽  
Scale Effects ◽  
Compound Channels ◽  
One Dimensional ◽  
Mobile Bed ◽  
Series Of Experiments ◽  
And Performance ◽  
Discharge Estimation ◽  
Fixed Boundaries

A series of experiments was carried out in a two-stage flume having a smooth main channel and smooth or rough floodplains to investigate the reliability and performance of four different one-dimensional methods for computing the discharge capacity of compound channels, namely, the single-channel method (SCM), the divided-channel method (DCM), the exchange discharge method (EDM), and the Ackers method (AM). Additional data from fixed- and mobile-bed compound laboratory channels with smooth and roughened floodplains and of a prototype compound river channel were also used in the computations. The boundary roughness and scale effects associated with the performance of the four methods are also examined. The results show that the EDM and the AM are able to simulate the measured discharge values more accurately than those of the traditional methods, namely, the DCM and the SCM. Although the error in discharge estimation produced by both the AM and the EDM was generally lower than 10% for both smooth and fixed boundaries, it increased up to 20% for mobile boundaries. Overall, the average relative error in discharge estimations using the AM and the EDM was about 5.4% and 7.1%, respectively, with a standard deviation of 6.7% and 6.8%, respectively. Key words: compound channel flow, stage-discharge relationship, one-dimensional methods.

scholarly journals Discharge estimation in compound channels with fixed and mobile bed

Sadhana ◽  
2009 ◽  
Vol 34 (6) ◽  
pp. 923-945 ◽  
Author(s):  
Galip Seckin ◽  
Mustafa Mamak ◽  
Serter Atabay ◽  
Mazen Omran
Keyword(s):  
Compound Channels ◽  
Mobile Bed ◽  
Discharge Estimation

scholarly journals Predicting discharge capacity of vegetated compound channels: uncertainty and identifiability of one-dimensional process-based models

2020 ◽  
Vol 24 (8) ◽  
pp. 4135-4167
Author(s):  
Adam Kiczko ◽  
Kaisa Västilä ◽  
Adam Kozioł ◽  
Janusz Kubrak ◽  
Elżbieta Kubrak ◽  
...  
Keyword(s):  
Discharge Capacity ◽  
Probabilistic Approach ◽  
River Channels ◽  
Compound Channels ◽  
One Dimensional ◽  
Practical Applications ◽  
Rigid Vegetation ◽  
Output Uncertainty ◽  
Hydraulic Conditions ◽  
Flexible Vegetation

Abstract. Despite the development of advanced process-based methods for estimating the discharge capacity of vegetated river channels, most of the practical one-dimensional modeling is based on a relatively simple divided channel method (DCM) with the Manning flow resistance formula. This study is motivated by the need to improve the reliability of modeling in practical applications while acknowledging the limitations on the availability of data on vegetation properties and related parameters required by the process-based methods. We investigate whether the advanced methods can be applied to modeling of vegetated compound channels by identifying the missing characteristics as parameters through the formulation of an inverse problem. Six models of channel discharge capacity are compared in respect of their uncertainty using a probabilistic approach. The model with the lowest estimated uncertainty in explaining differences between computed and observed values is considered the most favorable. Calculations were performed for flume and field settings varying in floodplain vegetation submergence, density, and flexibility, and in hydraulic conditions. The output uncertainty, estimated on the basis of a Bayes approach, was analyzed for a varying number of observation points, demonstrating the significance of the parameter equifinality. The results showed that very reliable predictions with low uncertainties can be obtained for process-based methods with a large number of parameters. The equifinality affects the parameter identification but not the uncertainty of a model. The best performance for sparse, emergent, rigid vegetation was obtained with the Mertens method and for dense, flexible vegetation with a simplified two-layer method, while a generalized two-layer model with a description of the plant flexibility was the most universally applicable to different vegetative conditions. In many cases, the Manning-based DCM performed satisfactorily but could not be reliably extrapolated to higher flows.

Replication of the Superstition and Performance Study by

2014 ◽  
Vol 45 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Robert J. Calin-Jageman ◽  
Tracy L. Caldwell
Keyword(s):  
Task Difficulty ◽  
Statistical Power ◽  
Meta Analysis ◽  
A Priori ◽  
Significant Heterogeneity ◽  
Performance Study ◽  
Improve Performance ◽  
Research Designs ◽  
Series Of Experiments ◽  
And Performance

A recent series of experiments suggests that fostering superstitions can substantially improve performance on a variety of motor and cognitive tasks ( Damisch, Stoberock, & Mussweiler, 2010 ). We conducted two high-powered and precise replications of one of these experiments, examining if telling participants they had a lucky golf ball could improve their performance on a 10-shot golf task relative to controls. We found that the effect of superstition on performance is elusive: Participants told they had a lucky ball performed almost identically to controls. Our failure to replicate the target study was not due to lack of impact, lack of statistical power, differences in task difficulty, nor differences in participant belief in luck. A meta-analysis indicates significant heterogeneity in the effect of superstition on performance. This could be due to an unknown moderator, but no effect was observed among the studies with the strongest research designs (e.g., high power, a priori sampling plan).

scholarly journals Different Reasons for Different Responses: A Review of Incumbents’ Adaptation in Carbon-Intensive Industries

2020 ◽  
pp. 108602661989399 ◽  
Author(s):  
Franziska Sump ◽  
Sangyoon Yi
Keyword(s):  
Carbon Emissions ◽  
Organizational Adaptation ◽  
Three Dimensions ◽  
External Shocks ◽  
Review Of The Literature ◽  
Organizational Responses ◽  
Environmental Pressure ◽  
One Dimensional ◽  
And Performance ◽  
Performance Heterogeneity

Organizations often respond in different ways to common external shocks. To advance theories on organizational adaptation and performance heterogeneity, it is essential to understand different reasons for different organizational responses. We examine how incumbents in carbon-intensive industries adapt to heightened environmental pressure to reduce carbon emissions. Based on a review of the literature, we propose three dimensions along which diverse organizational responses can be efficiently mapped out: goal, timing, and scope. Building on our proposed dimensions, we develop a typology of five different organizational responses. With this, we show that organizational responses are more diverse than a one-dimensional scale could show but that the heterogeneity is somehow limited as the positions on the dimensions are not independent but correlated. To understand this observed limited heterogeneity, we proceed by identifying reasons behind different organizational responses. Furthermore, we discuss the theoretical implications of our findings for research on organizational adaptation and sustainability.

Analysis of One-Dimensional Modelling for Flood Routing in Compound Channels

2011 ◽  
Vol 26 (5) ◽  
pp. 1065-1087 ◽  
Author(s):  
Pierfranco Costabile ◽  
Francesco Macchione
Keyword(s):  
Flood Routing ◽  
Compound Channels ◽  
One Dimensional

scholarly journals Slow light bimodal interferometry in one-dimensional photonic crystal waveguides

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Luis Torrijos-Morán ◽  
Amadeu Griol ◽  
Jaime García-Rupérez
Keyword(s):  
Photonic Crystal ◽  
Group Velocity ◽  
Communication Networks ◽  
Slow Light ◽  
Single Channel ◽  
Point Of Care ◽  
Semiconductor Industry ◽  
Optical Modulator ◽  
One Dimensional ◽  
Dimensional Photonic Crystal

AbstractStrongly influenced by the advances in the semiconductor industry, the miniaturization and integration of optical circuits into smaller devices has stimulated considerable research efforts in recent decades. Among other structures, integrated interferometers play a prominent role in the development of photonic devices for on-chip applications ranging from optical communication networks to point-of-care analysis instruments. However, it has been a long-standing challenge to design extremely short interferometer schemes, as long interaction lengths are typically required for a complete modulation transition. Several approaches, including novel materials or sophisticated configurations, have been proposed to overcome some of these size limitations but at the expense of increasing fabrication complexity and cost. Here, we demonstrate for the first time slow light bimodal interferometric behaviour in an integrated single-channel one-dimensional photonic crystal. The proposed structure supports two electromagnetic modes of the same polarization that exhibit a large group velocity difference. Specifically, an over 20-fold reduction in the higher-order-mode group velocity is experimentally shown on a straightforward all-dielectric bimodal structure, leading to a remarkable optical path reduction compared to other conventional interferometers. Moreover, we experimentally demonstrate the significant performance improvement provided by the proposed bimodal photonic crystal interferometer in the creation of an ultra-compact optical modulator and a highly sensitive photonic sensor.

On the Efficacy of Magnetorheological Dampers for Seismic Response Reduction

1997 ◽  
Author(s):  
S. J. Dyke ◽  
B. F. Spencer ◽  
M. K. Sain ◽  
J. D. Carlson
Keyword(s):  
Control Systems ◽  
Structural Response ◽  
Mr Damper ◽  
Seismic Protection ◽  
Seismic Excitations ◽  
One Dimensional ◽  
Mr Dampers ◽  
Earthquake Motion ◽  
Intrinsic Nonlinearity ◽  
Series Of Experiments

Abstract In this paper, the efficacy of magnetorheological (MR) dampers for seismic protection of structures is investigated through a series of experiments in which an MR damper is used to control a three story test structure subjected to a one-dimensional earthquake motion. Because of the intrinsic nonlinearity of the MR damper, several earthquake amplitudes are considered to investigate the performance, in terms of both peak and rms responses, of this control systems over a range of loading conditions. The results indicate that the MR damper is quite effective for structural response reduction over a wide class of seismic excitations.

scholarly journals Children’s Grammar of Null Subjects: Evidence from Comprehension

2012 ◽  
Vol 43 (4) ◽  
pp. 563-590 ◽  
Author(s):  
Robyn Orfitelli ◽  
Nina Hyams
Keyword(s):  
Language Development ◽  
First Language ◽  
Null Subjects ◽  
Null Subject ◽  
Series Of Experiments ◽  
And Performance ◽  
Children's Grammar

The null subject (NS) stage is one of the best-described hallmarks of first language development. We present a series of experiments assessing children’s interpretation of NS sentences, as a way of testing the two main competing analyses of the phenomenon: grammatical accounts, under which young children’s grammars license NSs in declarative sentences; and performance accounts, which hold that children have an adult grammar, but omit subjects in production for extrasyntactic reasons. Overall, we find evidence of an NS stage in comprehension, just as in production. This suggests that child and adult grammars differ, in line with grammatical accounts.

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