scholarly journals Strupczewski Method for Parametric Design Hydrographs in Ungauged Cross-Sections

2017 ◽  
Vol 64 (1) ◽  
pp. 49-67 ◽  
Author(s):  
Wiesław Gądek ◽  
Beata Baziak ◽  
Tamara Tokarczyk
Keyword(s):  
Cross Sections ◽  
Parametric Design ◽  
Complex Function ◽  
River Catchment ◽  
Flood Hydrograph ◽  
Skewness Coefficient ◽  
Design Hydrographs ◽  
Flow Changes ◽  
The Times ◽  
Two Parameters

AbstractNonparametric hydrographs, constructed by the method suggested by Archer, are usually used for developing parametric design hydrographs. Flow changes in time are described by the UPO ERR Gamma complex function, which denotes a Gamma curve reformulated to have a Unit Peak at the Origin (abbreviated to UPO), supplemented by the Exponential Replacement Recession (ERR) curve. It may be observed, that this solution does not work in some areas of the upper Vistula and middle Odra catchments when the times of the rising limb of a hydrograph are higher than the times of the falling limb, i.e. when the skewness coefficient approximates 0.5 or higher values. Better results can be achieved with the function suggested by Strupczewski in 1964. It is a solution which uses two parameters of the flood hydrograph. The objective of the present paper is to assess the Strupczewski method by comparing it with a complex UPO ERR Gamma function for gauged cross-sections in the upper Vistula and middle Odra catchments. The assessment was carried out for 30 gauged cross-sections (15 in each river catchment). The parameters were optimized for width-hydrograph descriptors W75 and W50, designed by the Archer method, and for the skewness coefficient s. Optimization using only two width-hydrograph descriptors aims to test how the Strupczewski method works for cross-sections for which the values of width-hydrograph descriptors W75 and W50 are known. The assessment of both methods was carried out with reference to a nonparametric hydrograph constructed by the Archer method. The results of these assessments suggest that the Strupczewski method may be used not only for gauged cross-sections, but also for ungauged ones.

Stresses and Deformations of Toroidal Shells of Elliptical Cross Section: With Applications to the Problems of Bending of Curved Tubes and of the Bourdon Gage

1952 ◽  
Vol 19 (1) ◽  
pp. 37-48
Author(s):  
R. A. Clark ◽  
T. I. Gilroy ◽  
E. Reissner
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Practical Interest ◽  
Closed Shell ◽  
Open Shell ◽  
Elliptical Cross Section ◽  
Axially Symmetric ◽  
Elliptical Cross ◽  
Two Parameters ◽  
Toroidal Shells

Abstract This paper is concerned with the application of the theory of thin shells to several problems for toroidal shells with elliptical cross section. These problems are as follows: (a) Closed shell subjected to uniform normal wall pressure. (b) Open shell subjected to end bending moments. (c) Combination of the results for the first and second problems in such a way as to obtain results for the stresses and deformations in Bourdon tubes. In all three problems the distribution of stresses is axially symmetric but only in the first problem are the displacements axially symmetric. The magnitude of stresses and deformations for given loads depends in all three problems on the magnitude of the two parameters bc/ah and b/c where b and c are the semiaxes of the elliptical section, a is the distance of the center of the section from the axis of revolution, and h is the thickness of the wall of the shell. For sufficiently small values of bc/ah trigonometric series solutions are obtained. For sufficiently large values of bc/ah asymptotic solutions are obtained. Numerical results are given for various quantities of practical interest as a function of bc/ah for the values 2, 1, 1/2, 1/4 of the semiaxes ratio b/c. It is suggested that the analysis be extended to still smaller values of b/c and to cross sections other than elliptical.

The Influence of Microstructure on the Tensile Damage of Lamellar Grey Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
A. Fontaine ◽  
G. Zambelli
Keyword(s):  
Cast Iron ◽  
Cross Sections ◽  
Damage Mechanics ◽  
Degradation Process ◽  
Grey Cast Iron ◽  
Heterogeneous Microstructure ◽  
The Matrix ◽  
Grey Cast ◽  
Mechanics Concepts ◽  
Two Parameters

ABSTRACTThe rupture behaviour of lamellar grey cast iron under tension depends on the overall damage suffered by the heterogeneous microstructure. In order to quantify the influence of microstructural components on the rupture behaviour of the material, it is therefore preferable to apply “Damage Mechanics” concepts rather than “Linear Fracture Mechanics”. In this preliminary study the damage process is assumed to be isotropic and two parameters are considered; firstly a damage limit σ0 and secondly, a damage rate B. Measurements made on a grey cast iron, cast in three different cross sections, show that these damage parameters may be used to separate the contributions of the graphite network and the matrix wich interact in the degradation process of the heterogeneous microstructure of lamellar grey cast iron.

The Calculation of Compressible Fluid Flow by the Use of a Generalized Entropy Chart

1948 ◽  
Vol 159 (1) ◽  
pp. 313-334 ◽  
Author(s):  
J. Kestin ◽  
A. K. Oppenheim
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Generalized Entropy ◽  
Specific Heats ◽  
Simplifying Assumptions ◽  
Isentropic Flows ◽  
Basic Equations ◽  
Two Parameters ◽  
Physical Phenomena ◽  
Velocity Pressure

Calculations of the flow of gases in pipes or ducts of varying cross-sections are important in the design of turbines and compressors, nozzles for various applications, exhaust or radiator ducts, thrust augmenting devices, etc. Provided certain simplifying assumptions are made, there is no difficulty in writing down the basic equations, but when the velocities are comparable to that of sound and compressibility effects cannot therefore be neglected, the solution of the transcendental equations present difficulties which hinder a clear discussion of the physical phenomena. Here the problem is solved by the use of a generalized entropy chart, off which results may be directly read. For example, if the conditions in the reservoir from which the gas is assumed to be discharged are known, the complete conditions at any given cross-section may be read off when two parameters at the section considered are specified. The parameters may include the velocity, pressure, density, temperature, local Mach number, local velocity of sound, area of cross-section, mass flow per unit area, momentum per second, etc. The method is not confined to isentropic flows and may be applied to such problems as the flow in straight pipes or convergent and divergent nozzles including losses by either friction or condensation shocks. The co-ordinates of the chart are: dimensionless entropy σ = ( s— s0) J/R and dimensionless enthalpy ι = h/h0 = T/T0 where the meaning of the symbols is given later. All other variables are expressed in terms of these two co-ordinates and tables for several values of the ratio of specific heats are included to facilitate the drawing of such charts. The method does not aim at presenting new facts, but its usefulness lies in the provision of a comprehensive graphical means of calculating one-dimensional flow of compressible fluids. The charts lend themselves to the construction of a mechanical device for simplifying their use, such as a portable scale with sliding curves.

scholarly journals Preliminary geophysical study for groundwater exploration in the eastern region of Islamabad

1996 ◽  
Vol 14 ◽  
Author(s):  
K. A. Khan
Keyword(s):  
Cross Sections ◽  
Groundwater Exploration ◽  
High Resistivity ◽  
Eastern Region ◽  
Unconfined Aquifers ◽  
Electrical Resistivity Survey ◽  
True Resistivity ◽  
Geophysical Study ◽  
Two Parameters ◽  
The Relationship

Geophysical study was carried out in the area lying to the east of Islamabad to identify potential aquifers and to establish the relationship between the geoelectric and hydrogeologic parameters. Electrical resistivity survey using the Schlumberger electrode configuration was carried out at 32 stations. Data processing and interpretation were done using a PC based software. The true resistivity and thickness of various subsurface horizons were interpreted in terms of geological columns and cross-sections to reveal the presence of clay, sand, gravel and boulders as the subsurface lithology. The wide occurrence of gravels and boulders suggest that most of the regions in the project area represent the promising zone of groundwater. Both confined and unconfined aquifers have been encountered. The resistivity information was used to plot Dar-Zarrouk curves across selected profiles in order to determine the electrical behaviour of the aquifer. These curves show that the surficial layer is composed of material of high resistivity while the second layer constitutes the aquifer having high longitudinal conductance. Finally, statistical analyses involving linear regression were carried out to find out the relationship between electric and hydraulic properties of the aquifers. The results indicate that there is no significant relationship between the two parameters. All the results were compiled to demarcate promising groundwater drill sites.

scholarly journals Modelling runoff at the plot scale taking into account rainfall partitioning by vegetation: application to stemflow of banana (<I>Musa</I> spp.) plant

2009 ◽  
Vol 6 (3) ◽  
pp. 4307-4347 ◽  
Author(s):  
J.-B. Charlier ◽  
R. Moussa ◽  
P. Cattan ◽  
Y.-M. Cabidoche ◽  
M. Voltz
Keyword(s):  
Soil Surface ◽  
Plant Canopy ◽  
Flood Events ◽  
Runoff Generation ◽  
Flood Hydrograph ◽  
Rainfall Depth ◽  
Relative Water ◽  
Two Parameters ◽  
Runoff Production ◽  
Modelling Approach

Abstract. Rainfall partitioning by vegetation modifies the intensity of rainwater reaching the ground, which affects runoff generation. Incident rainfall is intercepted by the plant canopy and then redistributed into throughfall and stemflow. Rainfall intensities at the soil surface are therefore not spatially uniform, generating local variations of runoff production that are disregarded in runoff models. The aim of this paper was to model runoff at the plot scale, accounting for rainfall partitioning by vegetation in the case of plants concentrating rainwater at the plant foot and promoting stemflow. We developed a lumped modelling approach, including a stemflow function that divided the plot into two compartments: one compartment including stemflow and the relative water pathways and one compartment for the rest of the plot. This stemflow function was coupled with a production function and a transfer function to simulate a flood hydrograph using the MHYDAS model. Calibrated parameters were a "stemflow coefficient", which compartmented the plot; the saturated hydraulic conductivity (Ks), which controls infiltration and runoff; and the two parameters of the diffusive wave equation. We tested our model on a banana plot of 3000 m2 on permeable Andosol (mean Ks=75 mm h−1) under tropical rainfalls, in Guadeloupe (FWI). Runoff simulations without and with the stemflow function were performed and compared to 18 flood events from 10 to 130 mm rainfall depth. Modelling results showed that the stemflow function improved the calibration of hydrographs according to the error criteria on volume and on peakflow and to the Nash and Sutcliffe coefficient. This was particularly the case for low flows observed during residual rainfall, for which the stemflow function allowed runoff to be simulated for rainfall intensities lower than the Ks measured at the soil surface. This approach also allowed us to take into account the experimental data, without needing to calibrate the runoff volume on Ks parameter. Finally, the results suggest a rainwater redistribution module should be included in distributed runoff models at a larger scale of the catchment.

scholarly journals Textural equilibrium melt geometries around tetrakaidecahedral grains

2018 ◽  
Vol 474 (2212) ◽  
pp. 20170639 ◽  
Author(s):  
John F. Rudge
Keyword(s):  
Grain Boundaries ◽  
Cross Sections ◽  
Mean Curvature ◽  
Dihedral Angles ◽  
Total Surface Energy ◽  
Space Filling ◽  
Energy Bound ◽  
Molten Materials ◽  
Two Parameters ◽  
Equilibrium Geometries

In textural equilibrium, partially molten materials minimize the total surface energy bound up in grain boundaries and grain–melt interfaces. Here, numerical calculations of such textural equilibrium geometries are presented for a space-filling tessellation of grains with a tetrakaidecahedral (truncated octahedral) unit cell. Two parameters determine the nature of the geometries: the porosity and the dihedral angle. A variety of distinct melt topologies occur for different combinations of these two parameters, and the boundaries between different topologies have been determined. For small dihedral angles, wetting of grain boundaries occurs once the porosity has exceeded 11%. An exhaustive account is given of the main properties of the geometries: their energy, pressure, mean curvature, contiguity and areas on cross sections and faces. Their effective permeabilities have been calculated, and demonstrate a transition between a quadratic variation with porosity at low porosities to a cubic variation at high porosities.

Classical analysis of intermolecular potentials for Ar–CO2 rotational collisions

2001 ◽  
Vol 79 (2) ◽  
pp. 211-220
Author(s):  
J C Belchior ◽  
J P Braga ◽  
N HT Lemes
Keyword(s):  
Cross Sections ◽  
Classical Trajectory ◽  
Intermolecular Potential ◽  
Potential Surfaces ◽  
Potential Energy Functions ◽  
Theoretical Investigations ◽  
Classical Trajectories ◽  
Multiple Collisions ◽  
Two Parameters ◽  
Scattering Cross Sections

Classical trajectory calculations have been performed for four potential energy functions to describe Ar–CO2 collisions. A comparison is given between classical cross sections calculated using the two most recent potential surfaces and two older intermolecular potential surfaces based on the electron gas model. The two-dimensional atom ellipsoid model has also been applied for the study of multiple collisions. The model was able to predict such a phenomenon in agreement with quantum scattering results previously published for an ab initio potential surface in the region of very low collision energy. On the other hand, the two older potentials showed multiple collision effects at very high energies. The comparison of the cross sections showed some deviations from the experimental data. By introducing two parameters, a modified surface is proposed by changing the most recent intermolecular potential. In this case the agreement with experimental measurements and theoretical scattering cross sections was considerably improved. It is concluded that global potential surfaces for describing Ar–CO2 interaction are not well established. To achieve the requirement of reproducing all properties of this system, the present work suggests that one needs further experimental and theoretical investigations. Key words: classical trajectories, dynamics, cross sections, Ar–CO2 collisions, potentials.

Rough Road Identification Method Based on Engine Speed Variation Rate

2013 ◽  
Vol 300-301 ◽  
pp. 959-966
Author(s):  
Yu Long Lei ◽  
Shun Bo Li ◽  
Hong Bo Liu
Keyword(s):  
Frequency Domain ◽  
Engine Speed ◽  
Threshold Value ◽  
Speed Variation ◽  
The Road ◽  
Variation Rate ◽  
The Times ◽  
Set Up ◽  
Shift Point ◽  
Two Parameters

On rough road busy-shifting often occurs when shifting law is built based on traditional two parameters (i.e., velocity and throttle). In order to resolve this problem, this paper provides a method of recognizing rough road and modifying shift point. At first, a dynamic model was set up to demonstrate the possibility of identifying rough road by longitudinal acceleration. Furthermore, advantages of the engine speed variation rate were analyzed, so engine speed variation rate distinguishing the rough road was proved better. Then the analysis of time-domain and frequency-domain of the engine speed variation rate was carried out .On the basis of the result, the method of frequency domain based on the FFT and “Cross Meter Method” based on the times of the instantaneous values of engine speed variation rate greater than the threshold value was proposed. At last, the method of modifying shift strategy was proposed on the rough road. Through the road test, it was effective to prevent busy-shifting on rough road.

scholarly journals Experimental Validation of a Novel Generator of Gas Mixtures Based on Axial Gas Pulses Coupled to a Micromixer

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 715
Author(s):  
Florian Noël ◽  
Claire Trocquet ◽  
Christophe A. Serra ◽  
Stéphane Le Calvé
Keyword(s):  
Experimental Validation ◽  
Gas Mixtures ◽  
Analytical Instrument ◽  
Pure Nitrogen ◽  
Gas Concentration ◽  
Multi Stage ◽  
The Times ◽  
Gas Dilution ◽  
Pollutant Mixtures ◽  
Two Parameters

In this work, a novel generator of gas mixtures previously numerically investigated and based on axial gas pulses coupled to a micromixer has been conceived, manufactured, and validated. Standard gaseous pollutant mixtures and pure nitrogen or pure air were introduced in a microdevice designed to generate alternating axial gas pulses which were downstream homogenized by means of a multi-stage modular micromixer. The dilution, and therefore the final pollutant concentration, was controlled by two parameters: the ratio between the times of each of the two gas pulses and the partial pressure of the pollutant(s) mixture added to the device. The gas mixture generator was coupled to an analyzer to monitor the concentration of aromatic pollutants. The response time was optimized to be lower than 2 min in accordance with the analytical instrument. The quantity of pollutants measured at the micromixer’s outlet increased linearly with the expected gas concentration of 3.7–100 ppb generated by this novel microfluidic generator and fitted perfectly with those obtained by a reference gas dilution bench. At 5 ppb, the precision on the concentration generated is close to that obtained with the conventional gas mixing bench, i.e., around 10%.

scholarly journals Microstructure of submucosal nervous plexuses of intestines of ducks

2020 ◽  
pp. 16-21
Author(s):  
D.S. Makhotyna ◽  
Keyword(s):  
Nervous System ◽  
Enteric Nervous System ◽  
Cross Sections ◽  
General Pattern ◽  
Age Groups ◽  
Intestinal Wall ◽  
Arithmetic Mean ◽  
Histological Structure ◽  
Two Parameters ◽  
Density Of Neurons

There are presented the results of the experimental research of the histological structure of the submucosal nerve plexuses in the intestines of domestic ducks (Anas platyrhynchos domesticus) of 9 age groups from diurnal to 1-year-old of the black White-Breasted breed. The definitions of topography, number, ganglia area, as well as density of neurons in them were determined on cross sections of the duodenum, jejunum, ileum, cecum and rectum. It is defined the nerve nodes and submucosal strands belonging to the enteric nervous system are located between the lamina muscularis mucosae and the inner layer of muscular tunic. In the cross section of the intestinal wall, the submucosal ganglia have the shape of narrow strips. In order to generalize the morphofunctional state of the nerve plexuses, there were determined two parameters: the average age indicator (AAI) of the intestine and intestine. AAI of a certain structure of each intestine was determined as the arithmetic mean of the values of its 9 age indicators. The AAI of a particular intestinal structure was determined as the arithmetic mean of the AAI quantities of the structure of all five intestines. The average number of submucosal ganglia did not increase with the age of the ducks, but changed with varying degrees of reliability in comparison with the previous age. In the intestines of diurnal to 1-day – 1-year-old ducks, the smallest number of submucosal ganglia was found in the cecum, and the largest was found in the rectum. The general pattern of the size dynamics of the submucosal ganglia in the intestines of ducks is an increase with age in their average area. There was found the smallest area of submucosal ganglia in the ileum in the group of ducks of different ages, and the largest was found in the duodenum and cecum. The lowest density of neurons in the submucosal ganglia is found in the cecum, the highest was found in the rectum. Changes in the morphometric parameters of the nerve plexuses ganglia in the intestines of ducks indicate the dynamic nature of changes in the morphofunctional state of the enteric nervous system.

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