Selection of one-dimensional sedimentation: models for on-line use

1995 ◽  
Vol 31 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Koen Grijspeerdt ◽  
Peter Vanrolleghem ◽  
Willy Verstraete
Keyword(s):  
Steady State ◽  
Selection Criteria ◽  
Data Sets ◽  
Concentration Profiles ◽  
A Posteriori ◽  
One Dimensional ◽  
On Line ◽  
Dynamic Concentration ◽  
Selection Of ◽  
Modelling Task

A comparative study of several recently proposed one-dimensional sedimentation models has been made. This has been achieved by fitting these models to steady-state and dynamic concentration profiles obtained in a down-scaled secondary decanter. The models were evaluated with several a posteriori model selection criteria. Since the purpose of the modelling task is to do on-line simulations, the calculation time was used as one of the selection criteria. Finally, the practical identifiability of the models for the available data sets was also investigated. It could be concluded that the model of Takács et al. (1991) gave the most reliable results.

scholarly journals Modeling the Dynamic Concentration Profiles and Efficacy of Type-I and Type-II Photopolymerization

2018 ◽  
Author(s):  
Jui-Teng Lin ◽  
Da-Chuan Cheng ◽  
Kuo-Ti Chen ◽  
Hsia-Wei Liu
Keyword(s):  
Steady State ◽  
Light Intensity ◽  
Light Exposure ◽  
Light Dose ◽  
Type I ◽  
Concentration Profiles ◽  
Type Ii ◽  
Photoinitiated Polymerization ◽  
Lower Light ◽  
Dynamic Concentration

The kinetics and efficacy profiles of photoinitiated polymerization are theoretically presented. For the same dose, lower light intensity achieves a higher steady-state-efficacy (SSE) in type-I; in contrast, type-II has an equal SSE. Higher light intensity has a faster rising efficacy, due to faster depletion of photoinitiator (PS) concentration. However, type-II process is also affected by the available oxygen. Higher light intensity produces more efficient singlet oxygen, resulting a higher transient efficacy, in which all intensities reach the same SSE when oxygen is completely depleted. With external oxygen, type-II efficacy increases with time, otherwise, it is governed only by the light dose, i.e., same dose achieves same efficacy. Moreover, type-II has an efficacy follows Bunsen Roscoe law (BRL), whereas type-I follows non-BRL. The measured type-I efficacy and gelation profile are analyzed by our analytic formulas. Schematics of the photocrosslinking stage defined by the availability of oxygen is developed, where both type-I and –II coexist until the oxygen is depleted. The overall efficacy may be enhanced by resupply of PS or oxygen during the light exposure. The roles of light dose and PS concentration on the efficacy of photoinitiated polymerization should be are governed a new concept of a volume efficacy (Ve), defined by the product of the crosslink (or gelation) depth (CD) and local [efficacy].

Integration of Unsteady Effects in the Turbocharger Design Process

2012 ◽  
Author(s):  
Apostolos Pesiridis ◽  
Sotirios Lioutas ◽  
Ricardo F. Martinez-Botas
Keyword(s):  
Steady State ◽  
Engine Performance ◽  
Weighted Averaging ◽  
Initial Attempt ◽  
Lower Efficiency ◽  
Turbocharged Diesel Engine ◽  
One Dimensional ◽  
Flow Through ◽  
Unsteady Effects ◽  
Selection Of

Turbocharger development is based on performance maps arising through steady state measurements, although the flow through the engine-turbocharger system is highly unsteady. This paper investigates the potential for integrating the effects from unsteady flow in the turbine map, in order to enhance the performance of the ICE-turbocharger system. It is, also, an initial attempt to set the framework for more accurate one-dimensional turbine simulations in order to improve the selection of turbocharger components and their matching with the ICE. The development of ‘equivalent unsteady’ maps is presented, based on energy-weighted averaging of available, unsteady, experimental data and its deviations from quasi-steady performance. The maps are subsequently used for a one dimensional (1D) simulation of a turbocharged diesel engine running at 800 RPM and 1600 RPM. A comparative assessment with results from simulations using a conventional steady-state map has shown important differences in turbine parameters (up to 12% lower efficiency and 6% lower mass flow parameter) but minor differences, of less than 1% in terms of engine performance and fuel consumption.

Confidentiality of Statistical Records: A Threat-Monitoring Scheme for On Line Dialogue

1976 ◽  
Vol 15 (01) ◽  
pp. 36-42 ◽  
Author(s):  
J. Schlörer
Keyword(s):  
Statistical Data ◽  
Cost Benefit ◽  
Data Bank ◽  
High Ratio ◽  
Point Of View ◽  
Data Sets ◽  
Monitoring Scheme ◽  
Access Controls ◽  
On Line ◽  
Bona Fide

From a statistical data bank containing only anonymous records, the records sometimes may be identified and then retrieved, as personal records, by on line dialogue. The risk mainly applies to statistical data sets representing populations, or samples with a high ratio n/N. On the other hand, access controls are unsatisfactory as a general means of protection for statistical data banks, which should be open to large user communities. A threat monitoring scheme is proposed, which will largely block the techniques for retrieval of complete records. If combined with additional measures (e.g., slight modifications of output), it may be expected to render, from a cost-benefit point of view, intrusion attempts by dialogue valueless, if not absolutely impossible. The bona fide user has to pay by some loss of information, but considerable flexibility in evaluation is retained. The proposal of controlled classification included in the scheme may also be useful for off line dialogue systems.

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