Optical measurement of post discharge density perturbations

1978 ◽  
Vol 56 (11) ◽  
pp. 1476-1481 ◽  
Author(s):  
John Tulip ◽  
Wayne Faszer ◽  
Herb Seguin
Keyword(s):  
Repetition Rate ◽  
Optical Method ◽  
Optical Measurement ◽  
Density Wave ◽  
Pulsed Discharge ◽  
Post Discharge ◽  
Open Flow ◽  
Density Perturbations ◽  
Discharge Density ◽  
Flow Duct

An optical method which relies upon the deflection of a He–Ne laser is used to measure gas density perturbations following a pulsed discharge. The damping time of these perturbations for a discharge in an open flow duct is400 μs, showing that the maximum repetition rate for a discharge free of perturbation is about 1 kHz. The density wave character immediately after the discharge is described.

Optical measurement of local permeability of flax fiber fabrics before liquid composite molding

2018 ◽  
Vol 52 (24) ◽  
pp. 3289-3297 ◽  
Author(s):  
Benoît Cosson
Keyword(s):  
Optical Method ◽  
Fiber Volume Fraction ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Optical Measurement ◽  
Transmission Measurement ◽  
Liquid Composite Molding ◽  
Fiber Volume ◽  
Filling Time ◽  
Composite Molding

Tracking the variability of natural fiber-based fabrics properties, such as local areal weight, fiber volume fraction, and therefore permeability, is crucial to optimize the parts processing of the bio-composites. This paper aims at developing a cost-effective and efficient optical method in order to predict the permeability of flax fabrics used in liquid composite molding processes. This method using an LCD monitor as light source and a reflex camera as a measurement device is based on light transmission measurement through fabric thickness. The raw data given by the camera are gray scale maps, transformed into areal weight maps. FEM software based on levelset method is finally used to highlight the influence of the local variability of the fiber volume fraction, and of the related fabrics porosity and permeability on the mold filling time. The proposed method can be directly implemented on the manufacturing line of the composites. It can be used to optimize, part-to-part, the resin consumption by predicting the resin flow through perform. Interestingly, this novel optical method is auto-calibrated and does not depend on picture resolution.

Optical measurement of isolated canine lung filtration coefficients after alloxan infusion

1998 ◽  
Vol 84 (4) ◽  
pp. 1381-1387 ◽  
Author(s):  
Joseph W. Klaesner ◽  
N. Adrienne Pou ◽  
Richard E. Parker ◽  
Charlene Finney ◽  
Robert J. Roselli
Keyword(s):  
Reflection Coefficient ◽  
Blood Volume ◽  
Optical Method ◽  
Statistical Difference ◽  
Optical Measurement ◽  
Venous Pressure ◽  
Optical Technique ◽  
Lung Weight ◽  
Percent Contribution ◽  
Multiple Indicator

In this study, lung filtration coefficient ( K fc) was measured in eight isolated canine lung preparations by using three methods: standard gravimetric (Std), blood-corrected gravimetric (BC), and optical. The lungs were held in zone III conditions and were subjected to an average venous pressure increase of 8.79 ± 0.93 (mean ± SD) cmH2O. The permeability of the lungs was increased with an infusion of alloxan (75 mg/kg). The resulting K fc values (in milliliters ⋅ min−1 ⋅ cmH2O−1 ⋅ 100 g dry lung weight−1) measured by using Std and BC gravimetric techniques before vs. after alloxan infusion were statistically different: Std, 0.527 ± 0.290 vs. 1.966 ± 0.283; BC, 0.313 ± 0.290 vs. 1.384 ± 0.290. However, the optical technique did not show any statistical difference between pre- and postinjury with alloxan, 0.280 ± 0.305 vs. 0.483 ± 0.297, respectively. The alloxan injury, quantified by using multiple-indicator techniques, showed an increase in permeability and a corresponding decrease in reflection coefficient for albumin (ςf). Because the optical method measures the product of K fc and ςf, this study shows that albumin should not be used as an intravascular optical filtration marker when permeability is elevated. However, the optical technique, along with another means of measuring K fc (such as BC), can be used to calculate the ςfof a tracer (in this study, ςfof 0.894 at baseline and 0.348 after injury). Another important finding of this study was that the ratio of baseline-to-injury K fc values was not statistically different for Std and BC techniques, indicating that the percent contribution of slow blood-volume increases does not change because of injury.

scholarly journals A Connection Between V/R and Polarization in Be Stars

2000 ◽  
Vol 175 ◽  
pp. 460-463 ◽  
Author(s):  
David McDavid ◽  
K.S. Bjorkman ◽  
J.E. Bjorkman ◽  
A.T. Okazaki
Keyword(s):  
Electron Scattering ◽  
Radiation Transfer ◽  
Density Wave ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Line Profiles ◽  
Short Term ◽  
Density Perturbations ◽  
Density Pattern ◽  
The Continuum

AbstractOkazaki (1991) and Papaloizou, Savonije, & Henrichs (1992) suggested that the quasi-cyclic V/R variability observed in the emission line profiles of many Be stars is caused by a precessing one-armed density wave in the circumstellar disk. It seems likely that the changing aspect of such a non-axisymmetric density pattern might also lead to a related variation of the continuum polarization. We have searched for such an effect in two well-studied Be shell stars, ζ Tau and 48 Lib, based on data compiled from several groups of observers from 1984 to 1998. Using the Monte Carlo radiation transfer code of Wood, Bjorkman, Whitney, & Code (1996), we have calculated the polarization due to electron scattering in Be disks in the presence of one-armed density perturbations. Although the notorious long and short term deviations from strict periodicity present in Be stars make it difficult to rigorously demonstrate the connection between the V/R variability and the polarization variations, we have been able to find specific modes that are consistent with the observed V/R line profile variations together with the suspected polarization cycles.

scholarly journals Inline monitoring of high cell density cultivation of Scenedesmus rubescens in a mesh ultra-thin layer photobioreactor by Photon Density Wave spectroscopy

2021 ◽  
Author(s):  
Michael Sandmann
Keyword(s):  
Light Scattering ◽  
Thin Layer ◽  
Optical Measurement ◽  
Density Wave ◽  
Matter Content ◽  
Photon Density ◽  
Dry Matter Content ◽  
Reference Analysis ◽  
Multiple Light Scattering

Abstract Objective Due to multiple light scattering that occurs inside and between cells, quantitative optical spectroscopy in turbid biological suspensions is still a major challenge. This includes also optical in-line determination of biomass in bioprocessing. Photon Density Wave (PDW) spectroscopy, a technique based on multiple light scattering, enables the independent and absolute determination of optical key parameters of concentrated cell suspensions, which allow to determine biomass during cultivation. Results A unique reactor type, called “mesh ultra-thin layer PBR” was used to create a highly concentrated algal suspension. PDW spectroscopy measurements were carried out continuously in the reactor without any need of sampling or sample preparation, over 3 weeks, and with 10-minutes time resolution. Conventional dry matter content and coulter counter measurements have been employed as established off-line reference analysis. The PBR allowed peak cell dry weight (CDW) of 33.4 g L−1. It is shown that the reduced scattering coefficient determined by PDW spectroscopy is strongly correlated with the biomass concentration in suspension and is thus suitable for process understanding. The reactor in combination with the fiber-optical measurement approach will lead to a better process management.

Thermal Property Measurement of Polymer Materials

2012 ◽  
Vol 591-593 ◽  
pp. 1089-1093
Author(s):  
Jiong Shiun Hsu ◽  
Bor Jiunn Wen ◽  
Liang Jian Chang
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermal Property ◽  
Optical Method ◽  
Measurement Method ◽  
Optical Measurement ◽  
Polymer Materials ◽  
Full Field ◽  
Property Measurement

Glass transition temperature is an important thermal property for polymer materials. When its temperature exceeds this temperature, the exhibiting characters dramatically changes. Although the experimental techniques suited to this temperature measurement are well-established, the full-field optical measurement method has not been employed to characterize this property. Therefore, this paper aims to measure the glass transition temperature using optical method.

scholarly journals Geometrical Error Analysis of Cold Forged AUV Propeller Blade Using Optical Measurement Method

2011 ◽  
Vol 383-390 ◽  
pp. 7117-7121 ◽  
Author(s):  
A.B. Abdullah ◽  
S.M. Sapuan ◽  
Z. Samad ◽  
H. M. T. Khaleed ◽  
N.A. Aziz
Keyword(s):  
Manufacturing Process ◽  
Optical Method ◽  
Measurement Method ◽  
Optical Measurement ◽  
Geometric Error ◽  
Blade Profile ◽  
Propeller Blade ◽  
Geometrical Error ◽  
Precision Forging ◽  
Complex Part

Accuracy is the key issue in the precision forging. Geometric and dimension errors are the two significant defects found in most of near net or net shape manufacturing process. It becomes more critical for complex part such as an AUV propeller blade. In this study, geometric error was quantified by comparing the blade profile obtained from nominal geometry of the blade and the profile constructed by commercial optical method namely Alicona system.

Sign in / Sign up

Export Citation Format

Share Document