scholarly journals Simple and robust method for determination of laser fluence thresholds for material modifications: an extension of Liu’s approach to imperfect beams

2021 ◽  
Vol 1 ◽  
pp. 7
Author(s):  
Mario Garcia-Lechuga ◽  
David Grojo
Keyword(s):  
Correction Method ◽  
Optical Path ◽  
Robust Method ◽  
Robust Solution ◽  
Advanced Control ◽  
Applied Approach ◽  
Laser Induced Damage ◽  
Airy Disk ◽  
Modification Of Materials

The so-called D-squared or Liu’s method is an extensively applied approach to determine the irradiation fluence thresholds for laser-induced damage or modification of materials. However, one of the assumptions behind the method is the use of an ideal spatial Gaussian beam that can lead in practice to significant errors depending on beam imperfections. In this work, we rigorously calculate the bias corrections required when applying the same method to Airy-disk like profiles. Those profiles are readily produced from any beam by insertion of an aperture in the optical path. Thus, the correction method gives a robust solution for exact threshold determination without any added technical complications as for instance advanced control or metrology of the beam. Illustrated by two case-studies, the approach holds potential to solve the strong discrepancies existing between the laser-induced damage thresholds reported in the literature.  It provides also an appropriate tool for new studies with the most extreme laser radiations.

scholarly journals Simple and robust method for determination of laser fluence thresholds for material modifications: an extension of Liu’s approach to imperfect beams

2021 ◽  
Vol 1 ◽  
pp. 7
Author(s):  
Mario Garcia-Lechuga ◽  
David Grojo
Keyword(s):  
Correction Method ◽  
Optical Path ◽  
Robust Solution ◽  
Gaussian Profile ◽  
Advanced Control ◽  
Applied Approach ◽  
Laser Induced Damage ◽  
Airy Disk ◽  
Modification Of Materials

The so-called D-squared or Liu’s method is an extensively applied approach to determine the irradiation fluence thresholds for laser-induced damage or modification of materials. However, one of the assumptions behind the method is the use of an ideal Gaussian profile that can lead in practice to significant errors depending on beam imperfections. In this work, we rigorously calculate the bias corrections required when applying the same method to Airy-disk like profiles. Those profiles are readily produced from any beam by insertion of an aperture in the optical path. Thus, the correction method gives a robust solution for exact threshold determination without any added technical complications as for instance advanced control or metrology of the beam. Illustrated by two case-studies, the approach holds potential to solve the strong discrepancies existing between the laser-induced damage thresholds reported in the literature.  It provides also an appropriate tool for new studies with the most extreme laser radiations.

scholarly journals Comparison of different models to calculate the viscosity of biogas and biomethane in order to accurately measure flow rates for conformity assessment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karine Arrhenius ◽  
Oliver Büker
Keyword(s):  
Binary Mixtures ◽  
Flow Rate ◽  
Correction Method ◽  
Gas Mixtures ◽  
Conformity Assessment ◽  
Flow Rates ◽  
Unknown Composition

AbstractThe study presents an optimised method to correct flow rates measured with a LFE flowmeter pre-set on methane while used for gas mixtures of unknown composition at the time of the measurement. The method requires the correction of the flow rate using a factor based on the viscosity of the gas mixtures once the composition is accurately known. The method has several different possible applications inclusive for the sampling of biogas and biomethane onto sorbent tubes for conformity assessment for the determination of siloxanes, terpenes and VOC in general. Five models for the calculation of the viscosity of the gas mixtures were compared and the models were used for ten binary mixtures and four multi-component mixtures. The results of the evaluation of the different models showed that the correction method using the viscosity of the mixtures calculated with the model of Reichenberg and Carr showed the smallest biases for binary mixtures. For multi-component mixtures, the best results were obtained when using the models of Lucas and Carr.

An optimised and robust method for the determination of uranium and plutonium in aqueous samples

1999 ◽  
Vol 50 (3) ◽  
pp. 579-583 ◽  
Author(s):  
Phillip E Warwick ◽  
Ian W Croudace ◽  
Alison A Dale
Keyword(s):  
Robust Method ◽  
Aqueous Samples

On Improving the Performances of Hydraulic Incremental Positioning Units with Mechanical Position Feedback

2012 ◽  
Vol 463-464 ◽  
pp. 1277-1280 ◽  
Author(s):  
Constantin Bucşan ◽  
Mihai Avram
Keyword(s):  
Real Time ◽  
Correction Method ◽  
Practical Application ◽  
Positioning Accuracy ◽  
Positioning Systems ◽  
Sensing System ◽  
Position Feedback ◽  
Time Determination ◽  
Interesting Solution

This paper presents a method for increasing the speed and the positioning accuracy of the positioning systems with mechanical position feedback. The method consists in using a position transducer for real time determination of the position of the load and correcting this position using an adequate algorithm. It is preferable not to modify the construction of the positioning unit, allowing the user to decide when to use this correction method according to the practical application. An interesting solution to this problem is to use an external space-position finding sensing system, as presented in the paper.

Experimental Determination of Side Boundary Effects on Stress Intensity Factors in Surface Flaws

1975 ◽  
Vol 97 (1) ◽  
pp. 45-51 ◽  
Author(s):  
M. Jolles ◽  
J. J. McGowan ◽  
C. W. Smith
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Taylor Series ◽  
Stress Intensity Factors ◽  
Taylor Series Expansion ◽  
Correction Method ◽  
Intensity Factors ◽  
Surface Flaws ◽  
Plate Width

A technique consisting of stress-freezing photoelasticity coupled with a Taylor Series Expansion of the maximum local in-plane shearing stress known as the Taylor Series Correction Method (TSCM) is applied to the determination of stress intensity factors (SIF’s) in flat bottomed surface flaws of flaw depth/length ratios of approximately 0.033. Flaw depth/thickness ratios of approximately 0.20 and 0.40 were studied as were plate width/crack length ratios of approximately 2.33 and 1.25, the former of which corresponded to a nearly infinite width. Agreement to well within 10 percent was found with the Rice-Levy and Newman theories using a depth-modified secant correction and equivalent flaw depth/length ratios. The Shah-Kobayashi Theory, when compared on the same basis, was lower than the experimental results. Using a modified net section stress correction suggested by Shah, agreement with the Shah-Kobayashi Theory was greatly improved but agreement with the other theories was poorer. On the basis of the experiments alone, it was found that the SIF was intensified by about 10 percent by decreasing the plate width/crack length from 2.33 to 1.25.

scholarly journals Absorbance Correction Method for Simultaneous Estimation of Nifedipine and Metoprolol Succinate in Their Synthetic Mixture Using From Spectrophotometry

2015 ◽  
Vol 1 (3) ◽  
pp. 151
Author(s):  
Sojitra Rajanit ◽  
Paras Virani ◽  
Hashumati Raj
Keyword(s):  
Accurate Method ◽  
Correction Method ◽  
Synthetic Mixture ◽  
Simultaneous Estimation ◽  
Metoprolol Succinate ◽  
Absorption Correction ◽  
Ich Guidelines ◽  
Development And Validation ◽  
Tablet Dosage

A new simple, economical, precise and accurate method are described for the simultaneous determination of Nifedipine (NIF) and Metoprolol Succinate (MET) in combined tablet dosage form. The proposed method was applied for the determination of Nifedipine and Metoprolol Succinate in synthetic mixture, for determination of sampling wavelength, 10?g/ml of each of NIF and MET were scanned in 200-400 nm range and sampling wavelengths were 313nm for NIF and 275.40nm for MET are selected for development and validation of absorption correction method. For this method linearity observed in the range of 5-25?g/ml for NIF and 25-125?g/ml for MET, and in their pharmaceutical formulation with mean percentage recoveries 100.68 and 100.33, respectively. The method was validated according to ICH guidelines and can be applied for routine quality control testing.

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