On Fluid Compressibility in Switch-Mode Hydraulic Circuits—Part II: Experimental Results

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
James D. Van de Ven
Keyword(s):  
Computational Model ◽  
Experimental Work ◽  
Experimental System ◽  
Experimental Results ◽  
System Pressure ◽  
Switch Mode ◽  
Air System ◽  
Entrained Air ◽  
Hydraulic Circuits ◽  
Fluid Compressibility

In this paper, the author presents experimental work with a generic switch-mode hydraulic circuit that aims to validate a previously presented computational model, with primary focus on the energy loss due to fluid compressibility. While multiple previous papers have presented experimental works with switch-mode hydraulic circuits, the presented experimental system is unique due the capability of in-flow measurement of the entrained air in the hydraulic fluid. A designed experiment was run that varied the entrained air, system pressure, and volume of the fluid experiencing pressure fluctuations, defined as the switched volume. The calculated volumetric efficiency from these experiments ranged from to 61% to 75%, with efficiency increasing with decreased levels of entrained air, system pressure, and switched volume. These efficiency trends and the pressure profile in the switched volume agree well with the computational model presented in Part I of this two part set (Van de Ven, 2013, “On Fluid Compressibility in Switch-Mode Hydraulic Circuits—Part I: Modeling and Analysis,” ASME J. Dyn. Sys., Meas., Control, 135(2), p. 021013). Differences between the experimental results and the computational model include approximately 10% higher predicted efficiency and pressure oscillations found in the experimental work that were not predicted by the model.

On Fluid Compressibility in Switch-Mode Hydraulic Circuits—Part I: Modeling and Analysis

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
Computational Experiment ◽  
High Efficiency ◽  
Major Influence ◽  
Hydraulic Fluid ◽  
System Pressure ◽  
Switch Mode ◽  
Entrained Air ◽  
Hydraulic Circuits ◽  
Fluid Compressibility

Fluid compressibility has a major influence on the efficiency of switch-mode hydraulic circuits due to the release of energy stored in fluid compression during each switching cycle and the increased flow rate through the high-speed valve during transition events. Multiple models existing in the literature for fluid bulk modulus, the inverse of the compressibility, are reviewed and compared with regards to their applicability to a switch-mode circuit. In this work, a computational model is constructed of the primary energy losses in a generic switch-mode hydraulic circuit with emphasis on losses created by fluid compressibility. The model is used in a computational experiment where the system pressure, switched volume, and fraction of air entrained in the hydraulic fluid are varied through multiple levels. The computational experiments resulted in switch-mode circuit volumetric efficiencies that ranged from 51% to 95%. The dominant energy loss is due to throttling through the ports of the high-speed valve during valve transition events. The throttling losses increase with the fraction of entrained air and the volume of fluid experiencing pressure fluctuations, with a smaller overall influence seen as a result of the system pressure. The results of the computational experiment indicate that to achieve high efficiency in switch-mode hydraulic circuits, it is critical to minimize both the entrained air in the hydraulic fluid and the fluid volume between the high-speed valve and the pump, motor, or actuator. These computational results are compared with experimental results in Part II of this two part paper series.

Effect of Fluidized Bed on Permeate Flux in Ceramic Membrane Cross-Flow Microfiltration

1995 ◽  
Vol 60 (12) ◽  
pp. 2074-2084
Author(s):  
Petr Mikulášek
Keyword(s):  
Fluidized Bed ◽  
Ceramic Membrane ◽  
Cross Flow ◽  
Experimental System ◽  
Experimental Results ◽  
Spherical Particles ◽  
Permeate Flux ◽  
Model Fluid ◽  
Optimum Porosity ◽  
Tubular Membranes

The microfiltration of a model fluid on an α-alumina microfiltration tubular membrane in the presence of a fluidized bed has been examined. Following the description of the basic characteristic of alumina tubular membranes, model dispersion and spherical particles used, some comments on the experimental system and experimental results for different microfiltration systems are presented. From the analysis of experimental results it may be concluded that the use of turbulence-promoting agents resulted in a significant increase of permeate flux through the membrane. It was found out that the optimum porosity of fluidized bed for which the maximum values of permeate flux were reached is approximately 0.8.

Comparing the Seismic Performance of Beam-Column Joints with and without SFRC when Subjected to Cyclic Loading

2012 ◽  
Vol 626 ◽  
pp. 85-89 ◽  
Author(s):  
Kay Dora Abdul Ghani ◽  
Nor Hayati Hamid
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Experimental Work ◽  
Concrete Beam ◽  
Steel Fiber ◽  
Precast Concrete ◽  
Experimental Results ◽  
Column Joint ◽  
Initial Cracks

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

Study on the Truck Scale Cheating Automatic Monitoring System Based on the GPRS

2013 ◽  
Vol 703 ◽  
pp. 240-243 ◽  
Author(s):  
Yan Jun Zhao ◽  
Shou Guang Cheng ◽  
Bin Qu
Keyword(s):  
Monitoring System ◽  
Measurement Data ◽  
Experimental System ◽  
Automatic Monitoring ◽  
Experimental Results ◽  
Pneumatic Conveying ◽  
Automatic Monitoring System ◽  
On Line ◽  
Conveying System

The truck scale is more and more applied on the weighing system. To seek illegal profits, many kinds of truck scale cheating method is found in the weighing system. To monitoring the truck scale cheating method, the truck scale cheating automatic monitoring system based on the GPRS is brought out in this paper. The truck scale cheating automatic monitoring system is designed. The monitoring system includes three parts: the monitoring terminal, the GPRS transmission module and the upper monitoring system. The truck scale measurement data of the sensors are collected by the monitoring terminal and sent to the upper monitoring system through the GPRS module. The experimental system is established on the pneumatic conveying system and the experiment is carried out. The experimental results show that the automatic monitoring system can on-line monitor the truck scale cheating method and improves the security of the truck scale weighing system.

scholarly journals Design and implementation of an I-V curvetracer dedicated to characterize PV panels

2021 ◽  
Vol 11 (3) ◽  
pp. 2011
Author(s):  
Mansour Zegrar ◽  
M’hamed Houari Zerhouni ◽  
Mohamed Tarik Benmessaoud ◽  
Fatima Zohra Zerhouni
Keyword(s):  
Photovoltaic Effect ◽  
Experimental System ◽  
Experimental Results ◽  
Solar Irradiation ◽  
Photovoltaic Module ◽  
Solar Photovoltaic ◽  
Efficient Manner ◽  
Photovoltaic Modules ◽  
Curve Tracer ◽  
Current Voltage

In recent years, solar photovoltaic energy is becoming very important in the generation of green electricity. Solar photovoltaic effect directly converts solar radiation into electricity. The output of the photovoltaic module MPV depends on several factors as solar irradiation and cell temperature. A curve tracer is a system used to acquire the PV current-voltage characteristics, in real time, in an efficient manner. The shape of the I-V curve gives useful information about the possible anomalies of a PV device. This paper describes an experimental system developed to measure the current–voltage curve of a MPV under real conditions. The measurement is performed in an automated way. This present paper presents the design, and the construction of I-V simple curve tracer for photovoltaic modules. This device is important for photovoltaic (PV) performance assessment for the measurement, extraction, elaboration and diagnose of entire current-voltage I-V curves for several photovoltaic modules. This system permits to sweep the entire I-V curve, in short time, with different climatic and loads conditions. An experimental test bench is described. This tracer is simple and the experimental results present good performance. Simulation and experimental tests have been carried out. Experimental results presented good performance.

scholarly journals Integrated experimental-computational analysis of a liver-islet microphysiological system for human-centric diabetes research

2021 ◽  
Author(s):  
Belén Casas ◽  
Liisa Vilén ◽  
Sophie Bauer ◽  
Kajsa Kanebratt ◽  
Charlotte Wennberg Huldt ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Computational Model ◽  
In Silico ◽  
Experimental Results ◽  
Published Data ◽  
Diabetes Research ◽  
Glucose Response ◽  
High Blood Glucose

Microphysiological systems (MPS) are powerful tools for emulating human physiology and replicating disease progression in vitro. MPS could be better predictors of human outcome than current animal models, but mechanistic interpretation and in vivo extrapolation of the experimental results remain significant challenges. Here, we address these challenges using an integrated experimental-computational approach. This approach allows for in silico representation and predictions of glucose metabolism in a previously reported MPS with two organ compartments (liver and pancreas) connected in a closed loop with circulating medium. We developed a computational model describing glucose metabolism over 15 days of culture in the MPS. The model was calibrated on an experiment-specific basis using data from seven experiments, where single-liver or liver-islet cultures were exposed to both normal and hyperglycemic conditions resembling high blood glucose levels in diabetes. The calibrated models reproduced the fast (i.e. hourly) variations in glucose and insulin observed in the MPS experiments, as well as the long-term (i.e. over weeks) decline in both glucose tolerance and insulin secretion. We also investigated the behavior of the system under hypoglycemia by simulating this condition in silico, and the model could correctly predict the glucose and insulin responses measured in new MPS experiments. Last, we used the computational model to translate the experimental results to humans, showing good agreement with published data of the glucose response to a meal in healthy subjects. The integrated experimental-computational framework opens new avenues for future investigations toward disease mechanisms and the development of new therapies for metabolic disorders.

scholarly journals Photovoltaic effect in Light Emitting Diodes

2016 ◽  
Vol 1 (1) ◽  
pp. 30-36
Author(s):  
K. Remidi ◽  
A. Cheknane ◽  
M. Haddadi
Keyword(s):  
Theoretical Model ◽  
Experimental Work ◽  
Photovoltaic Effect ◽  
Research Work ◽  
Electrical Characterization ◽  
Experimental System ◽  
Photoelectric Effect ◽  
Electrical Characteristics ◽  
Light Emitting

This paper describes an experimental work on the electrical characterization of commercial LED of different colors and their photoelectric effect. A research work has been carried out to develop the experimental measurement in order to show the presence of a photovoltaic effect on LEDs. For this purpose, we measured the electrical characteristics of individual LED and studied their light intensities using a pyranometer EPLEY. This work focused mainly on red, green and yellowLEDs. Moreover, we have implemented an experimental system for the measurement of sensitivity of different LEDs depending on the power of light from a light source. A comparison was made between theoretical model and experimental results.

Probabilistic Feature Attention as an Alternative to Variables in Phonotactic Learning

2021 ◽  
pp. 1-56
Author(s):  
Brandon Prickett
Keyword(s):  
Experimental Work ◽  
Experimental Results ◽  
Phonological Acquisition ◽  
Novel Approach ◽  
Free Model ◽  
Cast Doubt ◽  
Feature Attention ◽  
Phonotactic Learning ◽  
Past Experimental Work ◽  
Algebraic Representations

Abstract Since Halle (1962), explicit algebraic variables (often called alpha notation) have been commonplace in phonological theory. However, Hayes and Wilson (2008) proposed a variable-free model of phonotactic learning, sparking a debate about whether such algebraic representations are necessary to capture human phonological acquisition. While past experimental work has found evidence that suggested a need for variables in models of phonology (Berent et al. 2012, Moreton 2012, Gallagher 2013), this paper presents a novel mechanism, Probabilistic Feature Attention (PFA), that allows a variable-free model of phonotactics to predict a number of these phenomena. Additionally, experimental results involving phonological generalization that cannot be explained by variables are captured by this novel approach. These results cast doubt on whether variables are necessary to capture human-like phonotactic learning and provide a useful alternative to such representations.

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