scholarly journals Flow-Through Self-Standing Porous Silicon Sensor

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
David Martín-Sánchez ◽  
Salvador Ponce-Alcántara ◽  
Jaime García-Rupérez
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Multilayer Structure ◽  
Reflectance Spectra ◽  
Flow Through ◽  
Index Changes ◽  
Lift Off ◽  
Theoretical Simulations ◽  
Silicon Sensor ◽  
Good Agreement

A self-standing porous silicon (PS) multilayer structure detached from the substrate by the lift-off method and integrated with a microfluidic cell is presented. Experiments of refractive index changes sensing flow through open-ended pores are reported. We continuously recorded the reflectance spectra of the PS membrane each 30 s and measured the shift as different substances flowed through the structure. The experimental sensitivity values are in good agreement with the theoretical simulations performed.

Optical Detection of Polyacrylamide Swelling Behavior in a Porous Silicon Sensor

2008 ◽  
Vol 1133 ◽  
Author(s):  
Lisa M. Bonanno ◽  
Lisa A. DeLouise
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Optical Response ◽  
Crosslinking Density ◽  
Detection Sensitivity ◽  
Cross Linking ◽  
Volume Sensitivity ◽  
Swelling Capacity ◽  
Silicon Sensor

Abstract This work proves that a 1-D porous silicon (PSi) sensor is capable of monitoring the optical changes in a polyacrylamide (PAAm) hydrogel that correlate with swelling capacity. The PSi device was impregnated with PAAm hydrogel with varying crosslinking density and total solids. The optical response of the PSi sensor was utilized to distinguish the changes in refractive index of hydrogels with varying cross-linking densities. Refractive index values calculated by the composite hydrogel-PSi sensor response agree well (≤1% difference) with values measured using a bench-top refractometer. This work serves to build a foundation for creating a composite biochemical-responsive hydrogel-PSi sensor in which competitive binding of a target analyte would cause a reduction in hydrogel cross-linking density. Long-term goals of this work are to exploit the volume sensitivity of a PSi sensor and leverage the added optical response of the responsive hydrogel to increase target detection sensitivity in an affinity based biosensor.

scholarly journals Parallel Detection of Refractive Index Changes in a Porous Silicon Microarray Based on Digital Images

Sensors ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 750 ◽  
Author(s):  
Chuanxi Li ◽  
Zhenhong Jia ◽  
Peng Li ◽  
Hao Wen ◽  
Guodong Lv ◽  
...  
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Digital Images ◽  
Parallel Detection ◽  
Index Changes

scholarly journals Applying Speckle Noise Suppression to Refractive Indices Change Detection in Porous Silicon Microarrays

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2975
Author(s):  
Ruyong Ren ◽  
Zhenhong Jia ◽  
Jie Yang ◽  
Nikola Kasabov
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Change Detection ◽  
Noise Suppression ◽  
Refractive Index Change ◽  
Speckle Noise ◽  
Detection Accuracy ◽  
Value Change ◽  
Nonlocal Means ◽  
Index Changes

The gray value method can be used to detect gray value changes of each unit almost parallel to the surface image of PSi (porous silicon) microarrays and indirectly measure the refractive index changes of each unit. However, the speckles of different noise intensities produced by lasers on a porous silicon surface have different effects on the gray value of the measured image. This results in inaccurate results of refractive index changes obtained from the change in gray value. Therefore, it is very important to reduce the influence of speckle noise on measurement results. In this paper, a new algorithm based on the concepts of probability-based nonlocal-means filtering (PNLM), gradient operator, and median filtering is proposed for gray value restoration of porous silicon microarray images. A good linear relationship between gray value change and refractive index change is obtained, which can reduce the influence of speckle noise on the gray value of the PSi microarray image, improving detection accuracy. This means the method based on gray value change detection can be applied to the biological detection of PSi microarray arrays.

scholarly journals Speckle Noise Removal in Image-based Detection of Refractive Index Changes in Porous Silicon Microarrays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ruyong Ren ◽  
Zhiqing Guo ◽  
Zhenhong Jia ◽  
Jie Yang ◽  
Nikola K. Kasabov ◽  
...  
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Refractive Index Change ◽  
Speckle Noise ◽  
Noise Removal ◽  
Detection Sensitivity ◽  
Gray Level ◽  
Denoising Method ◽  
Index Changes ◽  
Gray Values

Abstract Based on porous silicon (PSi) microarray images, we propose a new method called the phagocytosis algorithm (PGY) for removing the influence of speckle noise on image gray values. In a theoretical analysis, speckle noise of different intensities is added to images, and a suitable denoising method is developed to restore the image gray level. This method can be used to reduce the influence of speckle noise on the gray values of PSi microarray images to improve the accuracy of detection and increase detection sensitivity. In experiments, the method is applied to detect refractive index changes in PSi microcavity images, and a good linear relationship between the gray level change and the refractive index change is obtained. In addition, the algorithm is applied to a PSi microarray image, and good results are obtained.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

New Hierarchically Structured Optical Materials for Dynamic Refractive Index Changes

2003 ◽  
Author(s):  
Bradley F. Chmelka ◽  
Earl Danielson ◽  
Michael D. Wyrsta
Keyword(s):  
Refractive Index ◽  
Optical Materials ◽  
Index Changes

Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

1985 ◽  
Vol 17 (8) ◽  
pp. 1475-1478 ◽  
Author(s):  
A P. C. Warner ◽  
G. A. Ekama ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Activated Sludge Process ◽  
Cycle Times ◽  
Waste Sludge ◽  
Volatile Solids ◽  
In Series ◽  
Flow Through ◽  
Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

Upward Vertical Two-Phase Flow Through an Annulus—Part II: Modeling Bubble, Slug, and Annular Flow

1992 ◽  
Vol 114 (1) ◽  
pp. 14-30 ◽  
Author(s):  
E. F. Caetano ◽  
O. Shoham ◽  
J. P. Brill
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubble Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Physical Phenomena ◽  
Good Agreement

Mechanistic models have been developed for each of the existing two-phase flow patterns in an annulus, namely bubble flow, dispersed bubble flow, slug flow, and annular flow. These models are based on two-phase flow physical phenomena and incorporate annulus characteristics such as casing and tubing diameters and degree of eccentricity. The models also apply the new predictive means for friction factor and Taylor bubble rise velocity presented in Part I. Given a set of flow conditions, the existing flow pattern in the system can be predicted. The developed models are applied next for predicting the flow behavior, including the average volumetric liquid holdup and the average total pressure gradient for the existing flow pattern. In general, good agreement was observed between the experimental data and model predictions.

LINEAR AND NONLINEAR INTERSUBBAND OPTICAL ABSORPTION OF FINITE AND INFINITE SEMI-PARABOLIC QUANTUM WELLS

2011 ◽  
Vol 25 (07) ◽  
pp. 497-507 ◽  
Author(s):  
M. J. KARIMI ◽  
A. KESHAVARZ ◽  
A. POOSTFORUSH
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Quantum Well ◽  
Quantum Wells ◽  
Resonant Peak ◽  
Energy Eigenvalues ◽  
Finite Case ◽  
Infinite Case ◽  
Index Changes

In this work, the optical absorption coefficients and the refractive index changes for the infinite and finite semi-parabolic quantum well are calculated. Numerical calculations are performed for typical GaAs / Al x Ga 1-x As semi-parabolic quantum well. The energy eigenvalues and eigenfunctions of these systems are calculated numerically. Optical properties are obtained using the compact density matrix approach. Results show that the energy eigenvalues and the matrix elements of the infinite and finite cases are different. The calculations reveal that the resonant peaks of the optical properties of the finite case occur at lower values of the incident photon energy with respect to the infinite case. Results indicate that the maximum value of the refractive index changes for the finite case are greater than that of the infinite case. Our calculations also show that in contrast to the infinite case, the resonant peak value of the total absorption coefficient in the case of the finite well is a non-monotonic function of the semi-parabolic confinement frequency.

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