scholarly journals Determination of best groyne combination for mitigating bank erosion

2019 ◽  
Vol 21 (5) ◽  
pp. 875-892
Author(s):  
Kaushik Bora ◽  
Hriday Mani Kalita
Keyword(s):  
Optimization Model ◽  
Optimization Problem ◽  
Bank Erosion ◽  
Flow Speed ◽  
Low Flow ◽  
Test Cases ◽  
Meandering Channel ◽  
Novel Approach

Abstract This paper presents a novel approach for determining the best combination of groynes in terms of their number, lengths and positions for controlling bank erosion. The vulnerable bank is considered to be protected if a very small value of water flow speed is achieved on the near bank area. A linked simulation–optimization model is developed in this regard which minimizes the total construction cost of the groyne project. At the same time, a constraint in terms of low flow speed in a predefined zone is incorporated, which helps in bank erosion prevention. In the simulation model, the depth-averaged shallow water equations are solved using a finite difference scheme. The optimization problem is formulated in three different approaches to tackle different types of in situ field problems. Genetic algorithm (GA) is used to solve the optimization problem. The proposed optimization model is used in two hypothetical test cases including one straight channel and one meandering channel. The results obtained with all the three formulations are found to be logical and establish the potential of the present model for application in real cases.

scholarly journals Invasive validation of a novel approach to determine aortic valve area with phase-contrast cardiac magnetic resonance imaging

2021 ◽  
Vol 22 (Supplement_2) ◽  
Author(s):  
F Troger ◽  
I Lechner ◽  
M Reindl ◽  
C Tiller ◽  
M Holzknecht ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Valve ◽  
Phase Contrast ◽  
Low Flow ◽  
Aortic Valve Area ◽  
Novel Approach ◽  
Valve Area ◽  
Flow States

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Society of Cardiology Background. Echocardiography is considered the standard method for screening and diagnosing aortic valve stenosis. However, inaccuracies in the determination of stroke-volumes by the continuity equation might particularly make the evaluation of patients with low-flow states difficult. Phase-contrast cardiac magnetic resonance (PC-CMR) is a promising tool in overcoming these limitations by the simultaneous determination of flow volumes and velocities across the stenotic valve. Purpose The aim of this study is to validate a novel approach based on PC-CMR against the invasive determination of the aortic valve area (AVA). Methods. PC-CMR was performed in 50 patients with moderate or severe AS (n = 52; age 72 years [interquartile range (IQR) 66 - 78], 38% of patients with low-flow states). All of them were referred to invasive evaluation of aortic stenosis by cardiac catheterization. Additionally, transthoracic echocardiography (TTE) was performed. Aortic valve area (AVA) was determined by PC-CMR (AVAPC-CMR) via plotting momentary flow across the valve against momentary flow velocity. AVAPC-CMR at different time points over the entire cardiac cycle was compared to invasively determined AVA, calculated according to the Gorlin-formula. Stroke volumes (SV) were determined by the Fick-principle, pressure gradients according to the modified Bernoulli-equation. Results. Mean AVA during the whole systolic phase showed a good correlation (r: 0.544, p < 0.001) with invasive AVA with a small bias (AVACMR: 0.78 cm², IQR: [0.60-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87], bias: 0.08 cm², p = 0.017). Intermethodical correlation and bias of AVA as measured by TTE (AVATTE) and AVAINVASIVE were similar to AVAPC-CMR (AVATTE: 0.81 cm²; IQR: [0.64-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87] r: 0.580, p < 0.001, bias 0.11 cm², p < 0.001). SV by PC-CMR showed a good correlation with Cine-CMR with no significant bias (r: 0.730, p < 0.001; SVPC-CMR: 86 ± 31 ml; SVCine: 85 ± 19 ml). Maximum gradients determined by PC‑CMR were 65 ± 2 9mmHg and showed a good inverse correlation with AVAPC-CMR (r: ‑0.371; p = 0.008). Conclusion. PC-CMR with continuous determination of flow volumes and flow velocities is able to determine AVA in patients with severe aortic stenosis with a tendency to overestimate AVA compared to invasively determined AVA.

scholarly journals High resolution in situ structural determination of heterogeneous specimen

2017 ◽  
Author(s):  
Benjamin A. Himes ◽  
Peijun Zhang
Keyword(s):  
Electron Tomography ◽  
Structural Determination ◽  
Viral Capsids ◽  
Link Type ◽  
Current State ◽  
Novel Approach ◽  
Cryo Electron Tomography ◽  
Insight Into

AbstractMacromolecular complexes are intrinsically flexible and often challenging to purify for structure determination by single particle cryoEM. Such complexes may be studied in situ using cryo-electron tomography combined with sub-tomogram alignment and classification, which in exceptional cases reaches sub-nanometer resolution, yielding insight into structure-function relationships. All maps currently deposited in the EMDB with resolution < 9 Å are from macromolecules that form ordered structural arrays, like viral capsids, which greatly simplifies structural determination. Extending this approach to more common specimens that exhibit conformational or compositional heterogeneity, and may be available in limited numbers, remains challenging. We developed emClarity, a GPU-accelerated image processing package, specifically to address fundamental hurdles to this aim, and demonstrate significant improvements in the resolution of maps compared to those generated using current state-of-the-art software. Furthermore, we devise a novel approach to sub-tomogram classification that reveals functional states not previously observed with the same data.The software is freely available from https://www.github.com/bHimes/emClarityTutorial documentation and videos at https://www.github.com/bHimes/emClarity/wiki

Determination of Concrete Strength Based on the Double-Hole Shear In Situ Test

2013 ◽  
Vol 357-360 ◽  
pp. 617-620
Author(s):  
Wen Li Zhu
Keyword(s):  
Structural Engineering ◽  
Shear Test ◽  
Shear Failure ◽  
Concrete Strength ◽  
Maximum Shear Stress ◽  
Critical Role ◽  
Tension Tests ◽  
Novel Approach

The determination of concrete strength in situ plays a critical role in the quality of structural engineering analysis and acceptance. The strength is usually determined through pure tension tests, like the common pull off test. However, in most applications, the shear strength is more interested. A novel approach, that is instrumented double-hole shear test, was presented for determining the strength of concrete. Drill two holes at two sides of measured concrete area, and the indentor is loaded from one hole in giving shear failure. Then, determine the strength of concrete according to the maximum shear stress when its destroyed. Conduct the double-hole shear test and the cubic compresion strength test on the different strength of concrete specimens and establish the correlations between the two strength values. The results show that the ratio of the two strength values is in the range from 0.085 to 0.351, which depends on the concrete strength.And the two strength values have a good linear relationship so it can provide a new method which can easily and reliably determine the concrete strength in situ.

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

The Use of TMAH to Etch Silicon and Expose Metal Bridging Failures

2000 ◽  
Author(s):  
Mark Morris ◽  
James Mohr ◽  
Esteban Ortiz ◽  
Steven Englebretson
Keyword(s):  
Failure Mechanism ◽  
Schottky Diodes ◽  
Tetramethylammonium Hydroxide ◽  
Novel Approach ◽  
Failure Location ◽  
Metal Etching ◽  
Plastic Mold

Abstract Determination of metal bridging failures on plastic encapsulated devices is difficult due to the metal etching effects that occur while removing many of the plastic mold compounds. Typically, the acids used to remove the encapsulation are corrosive to the metals that are found within the device. Thus, decapsulation can result in removal of the failure mechanism. Mechanical techniques are often not successful due to damage that results in destruction of the die and failure mechanism. This paper discusses a novel approach to these types of failures using a silicon etch and a backside evaluation. The desirable characteristics of the technique would be to remove the silicon and leave typical device metals unaffected. It would also be preferable that the device passivation and oxides not be etched so that the failure location is not disturbed. The use of Tetramethylammonium Hydroxide (TMAH), was found to fit these prerequisites. The technique was tested on clip attached Schottky diodes that exhibited resistive shorting. The use of the TMAH technique was successful at exposing thin solder bridges that extruded over the edge of the die resulting in failure.

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