scholarly journals Modeling Streambank Erosion on Composite Streambanks on a Watershed Scale

2017 ◽  
Vol 60 (3) ◽  
pp. 753-767 ◽  
Author(s):  
Aaron R. Mittelstet ◽  
Daniel E. Storm ◽  
Garey A. Fox ◽  
Peter M. Allen
Keyword(s):  
Shear Stress ◽  
Cross Sections ◽  
Assessment Tool ◽  
Critical Shear Stress ◽  
Coefficient Of Determination ◽  
Radius Of Curvature ◽  
Adjustment Factor ◽  
Stress Equation ◽  
Cross Sectional ◽  
Streambank Erosion

Abstract. Streambanks can be a significant source of sediment and phosphorus to aquatic ecosystems. Although the streambank-erosion routine in the Soil and Water Assessment Tool (SWAT) has improved in recent versions, the recently developed routine in SWAT 2012 has undergone limited testing, and the lack of site or watershed specific streambank data increases the uncertainty in the streambank-erosion predictions. There were two primary objectives of this research: (1) modify and test the 2012 SWAT streambank-erosion routine on composite streambanks, and (2) compare SWAT default and field-measured channel parameters and assess their influence on predicted streambank erosion. Three modifications were made to the SWAT 2012 streambank-erosion routine: (1) replacing the empirical effective shear stress equation with a process-based equation, (2) replacing bankfull width and depth measurements with top width and streambank height, and (3) incorporating an area-adjustment factor to account for non-trapezoidal cross-sections. The proposed streambank-erosion routine was tested on gravel-dominated streambanks on the Barren Fork Creek in northeastern Oklahoma. The study used data from 28 cross-sectional surveys, including streambank height and top width, side slope, thickness and texture of streambank layers, and an area-adjustment factor. Gravel d50 and kd-tc relationships were used to estimate the critical shear stress (tc) and the erodibility coefficient (kd), respectively. Incorporating the process-based shear stress equation, area-adjustment factor, or the top width and streambank height increased predicted streambank erosion by 85%, 31%, and -30%, respectively. Incorporating the process-based effective shear stress equation, sinuosity, radius of curvature, and measured bed slope improved the predicted versus observed streambank erosion Nash-Sutcliffe efficiency from -0.33 to 0.49 and the coefficient of determination (R2) from 0.02 to 0.65 at the ten study sites. Although the process-based effective shear stress equation was the most influential modification, incorporating the top width, streambank height, and area-adjustment factor more accurately represented the measured irregular cross-sections. Keywords: Composite streambanks, Fluvial erosion, Streambank erosion, SWAT.

Characterization of the Centroidal Geometry of Human Ribs

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Matthew W. Kindig ◽  
Richard W. Kent
Keyword(s):  
Cross Sections ◽  
Posterior Extremity ◽  
Radius Of Curvature ◽  
Cross Sectional ◽  
Surface Reconstructions ◽  
C1 Continuity ◽  
Best Fit ◽  
Novel Model ◽  
Geometric Primitives

While a number of studies have quantified overall ribcage morphology (breadth, depth, kyphosis/lordosis) and rib cross-sectional geometry in humans, few studies have characterized the centroidal geometry of individual ribs. In this study, a novel model is introduced to describe the centroidal path of a rib (i.e., the sequence of centroids connecting adjacent cross-sections) in terms of several physically-meaningful and intuitive geometric parameters. Surface reconstructions of rib levels 2–10 from 16 adult male cadavers (aged 31–75 years) were first extracted from CT scans, and the centroidal path was calculated in 3D for each rib using a custom numerical method. The projection of the centroidal path onto the plane of best fit (i.e., the “in-plane” centroidal path) was then modeled using two geometric primitives (a circle and a semiellipse) connected to give C1 continuity. Two additional parameters were used to describe the deviation of the centroidal path from this plane; further, the radius of curvature was calculated at various points along the rib length. This model was fit to each of the 144 extracted ribs, and average trends in rib size and shape with rib level were reported. In general, upper ribs (levels 2–5) had centroidal paths which were closer to circular, while lower ribs (levels 6–10) tended to be more elliptical; further the centroidal curvature at the posterior extremity was less pronounced for lower ribs. Lower ribs also tended to exhibit larger deviations from the best-fit plane. The rib dimensions and trends with subject stature were found to be consistent with findings previously reported in the literature. This model addresses a critical need in the biomechanics literature for the accurate characterization of rib geometry, and can be extended to a larger population as a simple and accurate way to represent the centroidal shape of human ribs.

scholarly journals ANALISIS ANGKUTAN SEDIMEN DASAR (BED LOAD) PADA SALURAN IRIGASI MATARAM YOGYAKARTA

Teknisia ◽  
2021 ◽  
Vol XXVI (1) ◽  
Author(s):  
Anggi Hermawan ◽  
◽  
Erwin Afiato ◽  
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Froude Number ◽  
Critical Shear Stress ◽  
Bed Load ◽  
Cross Sectional ◽  
Logarithmic Curve ◽  
Agricultural Areas ◽  
The Relationship ◽  
Downstream Area

In the last decade, the problem that has occurred in the Yogyakarta Mataram irrigation channel is the occurrence of sedimentation in the channel. This has an impact on reducing the cross-sectional discharge capacity of the canal and resulting in the supply of irrigation discharge to agricultural areas to be not optimal, so that agricultural productivity in the Mataram Irrigation Area will also not be optimal. The sediment transport (bed load) that occurs in an open channel can be approached using the empirical equation, including the Einstein, Meyer - Peter Muller and Frijlink equations. Sediment transport events that occur in the channel are stated based on the magnitude of the flow shear stress which exceeds the critical shear stress of the sediment particles. The quantity of sediment transport in the channel is stated on the logarithmic curve of the relationship between the froude number (fr) to the sediment transports (qb). The Curve explains that the increase in the froude number (fr) that occurs on each section of the channel will be directly proportional to the increase in the quantity of transport sediment (qb). The largest sediment transport occurred at the site of the Gambang and Nambongan channel section with a prediction of sediment transport of 3.57 m3/day and 3.67 m3/day, respectively. Thus, the potential for sediment transport that will settle in the downstream area is 3.67 m3/day.

Critical Shear Stress of Plates Above the Proportional Limit

1948 ◽  
Vol 15 (1) ◽  
pp. 7-12
Author(s):  
George Gerard
Keyword(s):  
Shear Stress ◽  
Aluminum Alloys ◽  
Critical Shear Stress ◽  
Experimental Program ◽  
Shear Stresses ◽  
Secant Modulus ◽  
Proportional Limit ◽  
Stress Equation ◽  
Compressive Stresses ◽  
Modulus Method

Abstract The secant-modulus method previously used for determining critical compressive stresses above the proportional limit has been extended for use in determining critical shear stresses above the proportional limit. The method was confirmed by an experimental program designed to check the use of the shear-secant modulus in the critical-shear-stress equation. Nondimensional critical-shear-stress design curves are presented for use with aluminum alloys.

Estimation of Bed Material Load using Artificial Intelligence Techniques

2021 ◽  
Author(s):  
Laxman Rathod ◽  
Bandita Barman ◽  
Bimlesh Kumar
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Critical Shear Stress ◽  
Coefficient Of Determination ◽  
Statistical Parameters ◽  
Inference System ◽  
Feed Forward Back Propagation ◽  
Wide Range ◽  
Material Load ◽  
Bed Material

<p>Estimation of sediment transport has significant implementation on water resources and hydraulic engineering. Transport of sediment is affected by flow and sediment properties and also climatic variation of the region. To examine the behaviour of sediment transport, wide range of experiments have been performed in laboratories. Most of the developed sediment transport formulations are empirical or semi empirical in nature. These days, the development of computer-aided programs such as MATLAB has opened the way for researchers to quickly study the generation mechanism. The “Artificial Neural Networks (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS)” can be used widely for developing sediment model. In this research, Feed Forward Back Propagation (FFBP) sort of ANN and Hybrid type based on the Sugeno approach of ANFIS is used to develop a model for bed material load transport using parameters like “channel discharge, width of the channel, flow depth,  friction/energy slope, mean size of sediment, bed shear stress, critical shear stress, gradation coefficient of the sediment particles, specific gravity, and viscosity”. Subsequently, the relationship between the expected and observed values is presented. The proposed approach showed superior results based on various statistical parameters, like the coefficient of determination (R<sup>2</sup>), Nash-Sutcliffe coefficient (NSE), Root mean square error (RMSE) and Mean absolute error (MAE). Correlation (R<sup>2</sup>), higher than (~0.90) indicates that ANN and ANFIS are compatible and capable of measuring the total bed material load.</p><p><strong>Keywords:</strong> Sediment transport, Bed material Load, ANFIS, ANN, FFBP</p>

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

The association between dietary inflammatory index and risk of central obesity in adults: An updated systematic review and meta-analysis

2020 ◽  
Vol 90 (5-6) ◽  
pp. 535-552 ◽  
Author(s):  
Mahdieh Abbasalizad Farhangi ◽  
Mahdi Vajdi
Keyword(s):  
Systematic Review ◽  
Observational Studies ◽  
Central Obesity ◽  
Assessment Tool ◽  
Weighted Mean Difference ◽  
Meta Analysis ◽  
Dietary Factors ◽  
Cross Sectional ◽  
Inflammatory Status ◽  
Obesity Indices

Abstract. Backgrounds: Central obesity, as a pivotal component of metabolic syndrome is associated with numerous co-morbidities. Dietary factors influence central obesity by increased inflammatory status. However, recent studies didn’t evaluate the association between central obesity and dietary inflammation index (DII®) that give score to dietary factors according to their inflammatory potential. In the current systematic review and meta-analysis, we summarized the studies that investigated the association between DII® with central obesity indices in the general populations. Methods: In a systematic search from PubMed, SCOPUS, Web of Sciences and Cochrane electronic databases, we collected relevant studies written in English and published until 30 October 2019. The population of included studies were apparently healthy subjects or individuals with obesity or obesity-related diseases. Observational studies that evaluated the association between DII® and indices of central obesity including WC or WHR were included. Results: Totally thirty-two studies were included; thirty studies were cross-sectional and two were cohort studies with 103071 participants. Meta-analysis of observational studies showed that higher DII® scores were associated with 1.81 cm increase in WC (Pooled weighted mean difference (WMD) = 1.813; CI: 0.785–2.841; p = 0.001). Also, a non-significant increase in the odds of having higher WC (OR = 1.162; CI: 0.95–1.43; p = 0.154) in the highest DII category was also observed. In subgroup analysis, the continent, dietary assessment tool and gender were the heterogeneity sources. Conclusion: The findings proposed that adherence to diets with high DII® scores was associated with increased WC. Further studies with interventional designs are necessary to elucidate the causality inference between DII® and central obesity indices.

Automated 3D measurement of fiber cross section morphology in handsheets

2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Image Plane ◽  
3D Measurement ◽  
Cross Sectional ◽  
Fiber Cross Section ◽  
Fiber Wall ◽  
Sectional Shape ◽  
Cross Section Geometry

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.

scholarly journals Chinesisation, adaptation and validation of the Chelsea Critical Care Physical Assessment Tool in critically ill patients: a cross-sectional observational study

BMJ Open ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. e045550
Author(s):  
Zhigang Zhang ◽  
Guoqiang Wang ◽  
Yuchen Wu ◽  
Jin Guo ◽  
Nannan Ding ◽  
...  
Keyword(s):  
Critical Care ◽  
Observational Study ◽  
Critically Ill ◽  
Content Validity ◽  
Assessment Tool ◽  
Western China ◽  
Validity Index ◽  
Cross Sectional ◽  
Physical Assessment ◽  
Content Validity Index

PurposeTo translate and adapt the Chelsea Critical Care Physical Assessment Tool (CPAx) into Chinese version (‘CPAx-Chi’), test the reliability and validity of CPAx-Chi, and verify the cut-off point for the diagnosis of intensive care unit-acquired weakness (ICU-AW).Study designCross-sectional observational study.MethodsForward and back translation, cross-cultural adaptation and pretesting of CPAx into CPAx-Chi were based on the Brislin model. Participants were recruited from the general ICU of five third-grade class-A hospitals in western China. Two hundred critically ill adult patients (median age: 53 years; 64% men) with duration of ICU stay ≥48 hours and Glasgow Coma Scale ≥11 were included in this study. Two researchers simultaneously and independently assessed eligible patients using the Medical Research Council Muscle Score (MRC-Score) and CPAx-Chi.ResultsThe content validity index of items was 0.889. The content validity index of scale was 0.955. Taking the MRC-Score scale as standard, the criterion validity of CPAx-Chi was r=0.758 (p<0.001) for researcher A, and r=0.65 (p<0.001) for researcher B. Cronbach’s α was 0.939. The inter-rater reliability was 0.902 (p<0.001). The area under the receiver operating characteristic curves of CPAx-Chi for diagnosing ICU-AW based on MRC-Score ≤48 were 0.899 (95% CI 0.862 to 1.025) and 0.874 (95% CI 0.824 to 0.925) for researcher B. The best cut-off point for CPAx-Chi for the diagnosis of ICU-AW was 31.5. The sensitivity was 87% and specificity was 77% for researcher A, whereas it was 0.621, 31.5, 75% and 87% for researcher B, respectively. The consistency was high when taking CPAx-Chi ≤31 and MRC-Score ≤48 as the cut-off points for the diagnosis of ICU-AW. Cohen’s kappa=0.845 (p=0.02) in researcher A and 0.839 (p=0.04) for researcher B.ConclusionsCPAx-Chi demonstrated content validity, criterion-related validity and reliability. CPAx-Chi showed the best accuracy in assessment of patients at risk of ICU-AW with good sensitivity and specificity at a recommended cut-off of 31.

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