Optimising the Efficiency of Storm Water Settling Basins by Means of Bypassing

1993 ◽  
Vol 27 (5-6) ◽  
pp. 105-110 ◽  
Author(s):  
F. H. L. R. Clemens ◽  
H. J. van Mameren ◽  
J. Kollen
Keyword(s):  
Boundary Conditions ◽  
Dynamic Behaviour ◽  
Storm Water ◽  
Mixed System ◽  
Research Needs ◽  
Settling Basin ◽  
Potential Increase ◽  
Overall Efficiency ◽  
Further Development

The reduction in pollutional load realised by storm water settling basins is potentially reduced due to the occurrence of a partially mixed situation in the basin or due to resuspension of settled material. The decrease in efficiency can theoretically be avoided by means of partially bypassing the basin. In order to quantify the potential increase in efficiency a settling basin in Amersfoort is taken as an example. This basin seems to behave like an almost completely mixed system, bypassing would increase the overall efficiency from ca. 34 % to ca 39 % for three overflows. The dynamic behaviour of settling basins, scouring conditions and the boundary conditions for which settling basins are to be designed are the research needs for further development in the field of storm water settling basins.

Analysis of the oscillatory behaviour of an industrial reactor for oxonation of propene; Combined models

1987 ◽  
Vol 52 (12) ◽  
pp. 2865-2875
Author(s):  
Josef Horák ◽  
Zdeněk Bělohlav ◽  
Petr Rosol ◽  
František Madron
Keyword(s):  
Liquid Phase ◽  
Dynamic Behaviour ◽  
Plug Flow ◽  
Equal Size ◽  
Mixed System ◽  
Oscillatory Behaviour ◽  
Industrial Reactor ◽  
Combined Models ◽  
Analysis Of Stability ◽  
Flow Element

Models have been used of the flow of the liquid phase in the reactor (cascade of two ideally mixed cells of different size, two equal-size cells with recycle, two equal-size cells with inlets to both cells and a model of two equal-size cells preceded with a back flow element with plug flow) to analyze the oscillatory states of an industrial reactor. Stable and instable steady states have been classified using analysis of pseudosteady states of conversion and temperature supplemented with a simulation of the dynamic behaviour. It has been that the deviations of the flow from an ideally mixed system may expand the region of the oscillatory behaviour. The detailed information about the character of the flow in the reactor and the way of feeding the reactor has been also found important for the analysis of stability.

An Exergy-Based Framework for Assessing Sustainability of IT Systems

2009 ◽  
Author(s):  
Amip J. Shah ◽  
Milton Meckler
Keyword(s):  
Life Cycle ◽  
Boundary Conditions ◽  
Life Cycle Analysis ◽  
Second Law ◽  
Research Needs ◽  
System Boundary ◽  
First Law Of Thermodynamics ◽  
Widespread Implementation ◽  
It Systems ◽  
Sustainability Theory

This paper proposes an exergy-based approach to evaluating the sustainability of different information technology (IT) systems. In reviewing existing standards around IT sustainability, we find that most of these metrics are based on energy efficiencies. Thermodynamically, these metrics imply sufficiency of a first-law analysis. In this paper, we show that such metrics based on the first-law of thermodynamics are necessary but not sufficient for evaluating the sustainability of IT systems. We discuss how — within the context of sustainability theory — exclusively relying on first-law metrics implicitly assumes a narrow set of system boundary conditions, and we show using an exergy-based life-cycle analysis that various classes of IT systems violate these boundary conditions. Thus, we suggest the need for metrics that include a second-law component as well as a life-cycle view of the IT system. Having identified such a metric, we demonstrate applicability of the framework for a sample IT system. We conclude by reflecting upon additional research needs and challenges associated with widespread implementation of such a framework.

scholarly journals Chladni Figures Simulation on a Rectangular Plate

2021 ◽  
Vol 26 (3) ◽  
Author(s):  
Pavlo Ihorovych Krysenko ◽  
Maksym Olehovych Zoziuk ◽  
Oleksandr Ivanovych Yurikov ◽  
Dmytro Volodymyrovych Koroliuk ◽  
Yurii Ivanovych Yakymenko
Keyword(s):  
Fourier Transform ◽  
Boundary Conditions ◽  
Rectangular Plate ◽  
Standing Waves ◽  
Physical Nature ◽  
Practical Significance ◽  
The Fourier Transform ◽  
Further Development ◽  
Top View ◽  
Chladni Figures

An analytical model for creating flat Chladni figures is presented. The equation of a standing wave in the simplest boundary conditions and the Fourier transform are used. Top view images are shown at different frequencies. The practical significance of the results obtained for the further development of the field of creating Chladni figures based on standing waves of different physical nature has been determined.

Investigations of the dynamic behaviour of the composition of combined sewage using on-line analyzers

2002 ◽  
Vol 45 (4-5) ◽  
pp. 77-83 ◽  
Author(s):  
H. Grüning ◽  
H. Orth
Keyword(s):  
Dynamic Behaviour ◽  
Scattered Light ◽  
Treatment Plant ◽  
Storm Water ◽  
Behaviour Pattern ◽  
Physical Parameters ◽  
Water Tank ◽  
Real Time Control ◽  
Term Operation ◽  
On Line

Continuously analyzing sensors today permit the recording of the dynamic behaviour pattern of pollutants in combined sewage through physical parameters. This report presents the results of such measurements. They were done in a storm water tank which is equipped with a combined sewage overflow and located at the end of a 360 ha catchment area. The results show that by using a combination of sensors for dissolved solids (using UV absorption) and of sensors for particulate solids (using scattered light measurement), reliable information on the composition of the combined sewage can be obtained. A statistical relationship between these two parameters and the chemical oxygen demand was established. The analyzing methods presented permit the real-time control of sewer systems on the basis of the pollution carried in the combined sewage. Through the information on the actual concentration of primary pollutants provided by on-line analysis, heavily polluted streams can be retained selectively in storm water tanks or directed to the treatment plant. However, due to the adverse conditions in a sewer system operational disturbances and stringent maintenance requirements are still an impediment to long-term operation.

Theoretical Development and Experimental Validation of Local Volume Displacement Sensors for a Vibrating Beam

2000 ◽  
Vol 123 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Marcellin B. Zahui ◽  
James W. Kamman ◽  
Koorosh Naghshineh
Keyword(s):  
Boundary Conditions ◽  
Experimental Validation ◽  
Theoretical Development ◽  
Local Volume ◽  
Control Techniques ◽  
General Methodology ◽  
Displacement Sensors ◽  
Vibrating Beams ◽  
Further Development ◽  
Linear Shape

Further development of local volume displacement sensors is presented. This development supports the implementation of noise control techniques that are based on minimization of local volume displacements, velocities, or accelerations of a vibrating structure. In this paper, we present a general methodology for the development of local volume displacement sensors for vibrating beams using P_olyV_inyliD_ene F_luoride (PVDF). This methodology was verified experimentally for a clamped beam. The local volume displacement measured using a single PVDF sensor matched the local volume displacement found using multiple accelerometer measurements. The resulting sensors span the entire length of the beam. They have a quadratic shape over that portion of the beam whose volume displacement is desired, and they have a linear shape over all other sections. Sensor design issues for different beam boundary conditions are discussed along with a presentation of some sample sensor shapes for various beam segments and boundary conditions.

A finite element application in the analysis and design of point-supported composite conoidal shell roofs: Suggesting selection guidelines

2010 ◽  
Vol 45 (3) ◽  
pp. 165-177 ◽  
Author(s):  
H S Das ◽  
D Chakravorty
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Dynamic Behaviour ◽  
Weight Ratio ◽  
High Strength ◽  
Conical Shells ◽  
Analysis And Design ◽  
Doubly Curved Shells ◽  
Doubly Curved ◽  
Bending Behaviour

In the present paper, a finite element code is applied to study the bending behaviour of point-supported composite conoidal shells. These doubly curved surfaces may look similar to single curved conical shells, but the non-developable conoids present much stiffer surfaces. Laminated composites offer a high strength-to-weight ratio, and composite conoidal shells can cover large column-free areas. These shells on point supports have wide applications in car parks and theatres. Research reports are available regarding the static and dynamic behaviour of composite and isotropic conoidal shells, but with different combinations of simply supported, clamped, and free boundary conditions. Reports on corner-point-supported isotropic rhombic plates and doubly curved shells also exist, but data on the bending behaviour of conoidal shells supported at discrete points only are missing. Hence, in the present paper, three different point-supported boundary conditions are considered with four different laminations, the relative performance of different shell options is studied in detail, and suitable approaches are proposed to choosing the best shell option among many in a practical situation.

scholarly journals Modeling magnetized star-planet interactions: boundary conditions effects

2013 ◽  
Vol 8 (S300) ◽  
pp. 330-334 ◽  
Author(s):  
Antoine Strugarek ◽  
Allan Sacha Brun ◽  
Sean P. Matt ◽  
Victor Reville
Keyword(s):  
Steady State ◽  
Boundary Conditions ◽  
Numerical Simulations ◽  
Stellar Wind ◽  
Stellar Surface ◽  
Numerical Studies ◽  
Rotational Evolution ◽  
Further Development ◽  
Steady State Solutions

AbstractWe model the magnetized interaction between a star and a close-in planet (SPMIs), using global, magnetohydrodynamic numerical simulations. In this proceedings, we study the effects of the numerical boundary conditions at the stellar surface, where the stellar wind is driven, and in the planetary interior. We show that is it possible to design boundary conditions that are adequate to obtain physically realistic, steady-state solutions for cases with both magnetized and unmagnetized planets. This encourages further development of numerical studies, in order to better constrain and undersand SPMIs, as well as their effects on the star-planet rotational evolution.

Sign in / Sign up

Export Citation Format

Share Document