A new method for separate reconstruction of fluorophore absorption and fluorescence lifetime in time domain: first results of a numerical experiment

2020 ◽  
Author(s):  
Alexander B. Konovalov ◽  
Vitaly V. Vlasov
Keyword(s):  
Numerical Experiment ◽  
Fluorescence Lifetime ◽  
Time Domain ◽  
New Method ◽  
First Results

Lubricant compatibility of FKM seals in synthetic oils

2019 ◽  
Vol 72 (5) ◽  
pp. 557-565
Author(s):  
Dilek Bulut ◽  
Tatjana Krups ◽  
Gerhard Poll ◽  
Ulrich Giese
Keyword(s):  
Polyethylene Glycol ◽  
Design Methodology ◽  
Elevated Temperatures ◽  
Failure Mechanisms ◽  
Standard Test ◽  
New Method ◽  
Static Tests ◽  
Content Type ◽  
Lip Seals ◽  
First Results

Purpose Elastomer seals are used in many applications. They are exposed to lubricants and additives at elevated temperatures, as well as mechanical stresses. They can only provide good sealing function when they have resistance to those factors. There are many elastomer-lubricant compatibility tests based on DIN ISO 1817 in industry. However, they are insufficient and costly. Correlations between the tests and the applications are inadequate. The purpose of this study is investigating lubricant compatibility of fluoroelastomers (FKM) seals in polyethylene-glycol (PG)- and polyalphaolefin (PAO)- based synthetic oils and developing a methodology to predict seal service life. Design/methodology/approach A new compatibility test which is more sufficient in terms of time and cost was developed and compared with a standard test, currently used in industry. Compatibility of FKM radial lip seals with PG- and PAO-based synthetic oils with different additives was investigated chemically and dynamically. Failure mechanisms were examined. Findings The new method and the Freudenberg Flender Test FB 73 11 008 showed similar results concerning damages and similar tendencies regarding wear. The additive imidazole derivative was the most critical. Static tests give indications of possible chemically active additives, but alone they are insufficient to simulate the dynamic applications. Originality/value The paper describes a new method to investigate elastomer-lubricant compatibility and gives first results with a variety of lubricants.

Early-photon guided reconstruction method for time-domain fluorescence lifetime tomography

2016 ◽  
Vol 14 (7) ◽  
pp. 071702-71706 ◽  
Author(s):  
Lin Zhang Lin Zhang ◽  
Chuangjian Cai Chuangjian Cai ◽  
Yanlu Lv Yanlu Lv ◽  
and Jianwen Luo and Jianwen Luo
Keyword(s):  
Fluorescence Lifetime ◽  
Time Domain ◽  
Reconstruction Method

A new method for the generation of representative time-domain turbulence excitations

2015 ◽  
Vol 58 ◽  
pp. 1-19 ◽  
Author(s):  
Jose Antunes ◽  
Philippe Piteau ◽  
Xavier Delaune ◽  
Laurent Borsoi
Keyword(s):  
Time Domain ◽  
New Method

Eigenvalue Decomposition Based Modified Newton Algorithm

2013 ◽  
Vol 347-350 ◽  
pp. 2586-2589
Author(s):  
Wen Jun Wang ◽  
Ju Bo Zhu ◽  
Xiao Jun Duan
Keyword(s):  
Convergence Rate ◽  
Numerical Experiment ◽  
Hessian Matrix ◽  
New Method ◽  
Eigenvalue Decomposition ◽  
Newton Algorithm ◽  
Negative Eigenvalues ◽  
Classical Algorithm ◽  
Newton Direction ◽  
Modified Algorithm

When the Hessian matrix is not positive, the Newton direction maybe not the descending direction. A new method named eigenvalue decomposition based modified Newton algorithm is presented, which first takes eigenvalue decomposition on the Hessian matrix, then replaces the negative eigenvalues with their absolutely values, finally reconstruct Hessian matrix and modify searching direction. The new searching direction is always the descending direction, and the convergence of the algorithm is proved and conclusion on convergence rate is presented qualitatively. At last, a numerical experiment is given for comparing the convergence domains of modified algorithm and classical algorithm.

scholarly journals In Vivo Time Domain Optical Imaging of Renal Ischemia-Reperfusion Injury: Discrimination Based on Fluorescence Lifetime

2007 ◽  
Vol 6 (5) ◽  
pp. 7290.2007.00030 ◽  
Author(s):  
Abedelnasser Abulrob ◽  
Eric Brunette ◽  
Jacqueline Slinn ◽  
Ewa Baumann ◽  
Danica Stanimirovic
Keyword(s):  
Optical Imaging ◽  
Fluorescence Lifetime ◽  
Fluorescence Intensity ◽  
Time Domain ◽  
Ex Vivo ◽  
Renal Ischemia ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging ◽  
Lifetime Analysis

Fluorescence lifetime is an intrinsic parameter of the fluorescent probe, independent of the probe concentration but sensitive to changes in the surrounding microenvironment. Therefore, fluorescence lifetime imaging could potentially be applied to in vivo diagnostic assessment of changes in the tissue microenvironment caused by disease, such as ischemia. The aim of this study was to evaluate the utility of noninvasive fluorescence lifetime imaging in distinguishing between normal and ischemic kidney tissue in vivo. Mice were subjected to 60-minute unilateral kidney ischemia followed by 6-hour reperfusion. Animals were then injected with the near-infrared fluorescence probe Cy5.5 or saline and imaged using a time-domain small-animal optical imaging system. Both fluorescence intensity and lifetime were acquired. The fluorescence intensity of Cy5.5 was clearly reduced in the ischemic compared with the contralateral kidney, and the fluorescence lifetime of Cy5.5 was not detected in the ischemic kidney, suggesting reduced kidney clearance. Interestingly, the two-component lifetime analysis of endogenous fluorescence at 700 nm distinguished renal ischemia in vivo without the need for Cy5.5 injection for contrast enhancement. The average fluorescence lifetime of endogenous tissue fluorophores was a sensitive indicator of kidney ischemia ex vivo. The study suggests that fluorescence lifetime analysis of endogenous tissue fluorophores could be used to discriminate ischemic or necrotic tissues by noninvasive in vivo or ex vivo organ imaging.

Detecting the medieval cod trade: a new method and first results

2008 ◽  
Vol 35 (4) ◽  
pp. 850-861 ◽  
Author(s):  
James Barrett ◽  
Cluny Johnstone ◽  
Jennifer Harland ◽  
Wim Van Neer ◽  
Anton Ervynck ◽  
...  
Keyword(s):  
New Method ◽  
First Results
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