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Relevant bibliographies by topics / Impurities identification

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Academic literature on the topic 'Impurities identification'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 May 2024

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Journal articles on the topic "Impurities identification"

1

Qiu, Fenghe, and Daniel L. Norwood. "Identification of Pharmaceutical Impurities." Journal of Liquid Chromatography & Related Technologies 30, no. 5-7 (2007): 877–935. http://dx.doi.org/10.1080/10826070701191151.

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Reddy Gopa, Sudheer Kumar, Pradeep Kumar Brahman, and Mallu Usenireddy. "Synthesis, Identification and Charcaterization of Potential impurities of Pomalidomide." Research Journal of Chemistry and Environment 27, no. 3 (2023): 86–92. http://dx.doi.org/10.25303/2703rjce086092.

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Pomalidomide is used for treating multiple myeloma and was synthesized for commercial use as a drug substance in highly pure form. In the process of synthesis of pure drug of pomalidomide, there is a possibility of formation of process related impurities. These impurities must be identified and controlled for producing safe medicine. In view of this, present study aimed at synthesizing four potential impurities of pomalidomide such as benzyldione, 5 – amino, desamino and nitrodion impurities. All these impurities were effectively synthesized and subsequently characterized using FT-IR, NMR and Mass spectroscopic analysis. In addition, a simple and accurate HPLC method was developed and validated for the separation and quantification of pomalidomide and its impurities synthesized in the study. The method utilizes kromasil C18 (4.6×150 mm, 5μm) column, 0.1 % orthophosphoric acid at pH 1.90±0.05 as mobile phase A, acetonitrile and mobile phase A in 60:40(v/v) as mobile phase B at 1.0 mL/min flow in gradient elution mode and UV detection at 220 nm. The method produces all validation parameters under the acceptable levels and can effectively estimate the impurities synthesized in the study. Based on the experimental findings, it can be concluded that the impurities synthesized in the developed procedure should be effectively used as reference standards for identifying and controlling the impurities in the manufacturing process of pomalidomide formulations.

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Sunil Kumar, I. V., G. S. R. Anjaneyulu, and V. Hima Bindu. "Identification and synthesis of impurities formed during sertindole preparation." Beilstein Journal of Organic Chemistry 7 (January 7, 2011): 29–33. http://dx.doi.org/10.3762/bjoc.7.5.

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Sertindole (1), an atypical anti-psychotic drug is used for the treatment of schizophrenia. During the laboratory optimization and later during its bulk synthesis the formation of various impurities was observed. The impurities formed were monitored and their structures were tentatively assigned on the basis of their fragmentation patterns in LC-MS. Most of the impurities were synthesized and their assigned constitutions confirmed by co-injection in HPLC. We describe herein the formation, synthesis and characterization of these impurities. Our study will be of immense help to others to obtain chemically pure sertindole.

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4

Westwood, Glenn. "Nuclear Magnetic Resonance Spectroscopy of Trace Organic Impurities Extracted from a Corrosion Inhibitor and a Semiaqueous Residue Remover." Solid State Phenomena 219 (September 2014): 284–87. http://dx.doi.org/10.4028/www.scientific.net/ssp.219.284.

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Within the next ten years, advanced semiconductor manufacturing will move into the sub-10 nm regime [1]. At these dimensions, there is concern that molecular scale impurities (≤ 1 nm diameter) within cleaning chemistries will have an increasing impact on wafer cleanliness, device yield, and performance. Considering that these impurities may be on the same size scale as some of the active ingredients, this will raise significant challenges for solution developers in terms of impurity identification and prevention. Herein, we will describe our efforts to better understand the impurities within a semi-aqueous residue remover (RR). This work has primarily focused on identifying trace water-insoluble impurities not readily detectable by standard impurity characterization techniques, such as gas and liquid chromatography. The first part of this project involves a proof of concept study of isolating known impurities from a corrosion inhibitor (CI), and the second part of this study is the identification of unknown impurities within RR and the identification of the source of these impurities.

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Dureja, P., R. S. Tanwar, and S. S. Tomar. "Identification of impurities in technical monocrotophos." Toxicological & Environmental Chemistry 18, no. 2-3 (1988): 205–10. http://dx.doi.org/10.1080/02772248809357312.

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Dureja, P., R. S. Tanwar, and Partha P. Choudhary. "Identification of impurities in technical metalaxyl." Chemosphere 41, no. 9 (2000): 1407–10. http://dx.doi.org/10.1016/s0045-6535(99)00543-3.

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Arzamastsev, A. P., T. Yu Luttseva, N. A. Klyuev, and N. P. Sadchikova. "Mass-spectrometric identification of impurities in Ditilin." Pharmaceutical Chemistry Journal 33, no. 12 (1999): 665–70. http://dx.doi.org/10.1007/bf02974945.

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Hong, Jongbae, and Aiguo Xu. "Nondestructive identification of impurities in granular medium." Applied Physics Letters 81, no. 25 (2002): 4868–70. http://dx.doi.org/10.1063/1.1522829.

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9

Xiong, Kaihe, Xingling Ma, Na Cao, et al. "Identification, characterization and HPLC quantification of impurities in apremilast." Analytical Methods 8, no. 8 (2016): 1889–97. http://dx.doi.org/10.1039/c5ay01759a.

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A new compound Imp-F was obtained and the structures were elucidated by using spectral data (NMR, MS, and IR); the potential process-related impurities were speculated in the apremilast drug; LC conditions were optimized and an effective HPLC method for the quantitative determination of the potential process-related impurities in apremilast was developed.

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10

Li, Xianjiang, Wen Ma, Bingxin Yang, Mengling Tu, Qinghe Zhang, and Hongmei Li. "Impurity Profiling of Dinotefuran by High Resolution Mass Spectrometry and SIRIUS Tool." Molecules 27, no. 16 (2022): 5251. http://dx.doi.org/10.3390/molecules27165251.

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Dinotefuran (DNT) is a neonicotinoid insecticide widely used in pest control. Identification of structurally related impurities is indispensable during material purification and pesticide registration and certified reference material development, and therefore needs to be carefully characterized. In this study, a combined strategy with liquid chromatography high-resolution mass spectrometry and SIRIUS has been developed to elucidate impurities from DNT material. MS and MS/MS spectra were used to score the impurity candidates by isotope score and fragment tree in the computer assisted tool, SIRIUS. DNT, the main component, worked as an anchor for formula identification and impurity structure elucidation. With this strategy, two by-product impurities and one stereoisomer were identified. Their fragmentation pathways were concluded, and the mechanism for impurity formation was also proposed. This result showed a successful application for combined human intelligence and machine learning, in the identification of pesticide impurities.

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Dissertations / Theses on the topic "Impurities identification"

1

McCarthy, Patrick Kieran. "HPLC and immunochemical detection of gliadin impurities in wheat and wheat products." Thesis, Nottingham Trent University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253810.

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2

Marchal, Cathie. "Développement de méthodes analytiques pour la caractérisaton de lots industriels du nitroxyde SG1." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4767.

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Ce travail de thèse s’inscrit dans un contexte industriel. Il consiste en la caractérisation de lots bruts de SG1 : le N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle. La spécificité de cette espèce est son caractère radicalaire stable. La première partie de ce travail consistait à développer une méthode d’analyse, facilement applicable en laboratoire d’analyse de contrôle sur site industriel pour la caractérisation de la pureté en SG1 dans des lots synthétisés. La méthode choisie a été développée par chromatographie liquide haute performance (HPLC). Pour ce faire, un étalon de SG1 a été préparé par purification de SG1 brut industriel en utilisant la technique séparative chromatographique de partage centrifuge (CPC). L’identification des impuretés suspectées majoritaires dans les lots de SG1 bruts a ensuite été réalisée par spectroscopie RMN ou par l’étude des fragments obtenus par spectrométrie de masse en tandem par ionisation electrospray. A l’aide de ces techniques, quinze impuretés majori- taires ont été identifiées. Des méthodes de quantification ont ensuite été développées pour douze de ces impuretés par diverses techniques analytiques chromatographiques : par HPLC-UV, HPLC-MS ou GC-MS ou par des techniques spectroscopiques Infra-Rouge ou encore par conductimétrie<br>This PhD study has been carried out within an industrial context. It deals with the characterization of industrial batches of N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle also called SG1. The distinctive feature of this molecule lies in its specific stability which is uncommon for radical species. The first part of this study consists in developping an analytical method, easy to implement in a QC laboratory for the determination of SG1 purity. The chosen analytical method has been developped by High Performances Liquid Chromatography (HPLC). This method requires the use of a standard sample of SG1, which has been obtained after purification of industrial batches of SG1 by the use of an innovative separative technology, the Centrifugal Partition Chromatography (CPC). The identification of the impurities, suspected as the major impurities in the industrial batches of SG1, has been carried out by NMR spectroscopy or by the study of their fragmentation observed by Tandem Mass Spectrometry – Electrospray Ionization. The use of these techniques enabled the identification of fifteen major impurities. Quantification methods by various techniques (HPLC-UV, HPLC-MS, GC-MS, other direct spectroscopic techniques like Infra-Red or other types of techniques like conductimetry) have been developped for twelve impurities

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Marchal, Cathie. "Développement de méthodes analytiques pour la caractérisaton de lots industriels du nitroxyde SG1." Electronic Thesis or Diss., Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4767.

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Ce travail de thèse s’inscrit dans un contexte industriel. Il consiste en la caractérisation de lots bruts de SG1 : le N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle. La spécificité de cette espèce est son caractère radicalaire stable. La première partie de ce travail consistait à développer une méthode d’analyse, facilement applicable en laboratoire d’analyse de contrôle sur site industriel pour la caractérisation de la pureté en SG1 dans des lots synthétisés. La méthode choisie a été développée par chromatographie liquide haute performance (HPLC). Pour ce faire, un étalon de SG1 a été préparé par purification de SG1 brut industriel en utilisant la technique séparative chromatographique de partage centrifuge (CPC). L’identification des impuretés suspectées majoritaires dans les lots de SG1 bruts a ensuite été réalisée par spectroscopie RMN ou par l’étude des fragments obtenus par spectrométrie de masse en tandem par ionisation electrospray. A l’aide de ces techniques, quinze impuretés majori- taires ont été identifiées. Des méthodes de quantification ont ensuite été développées pour douze de ces impuretés par diverses techniques analytiques chromatographiques : par HPLC-UV, HPLC-MS ou GC-MS ou par des techniques spectroscopiques Infra-Rouge ou encore par conductimétrie<br>This PhD study has been carried out within an industrial context. It deals with the characterization of industrial batches of N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle also called SG1. The distinctive feature of this molecule lies in its specific stability which is uncommon for radical species. The first part of this study consists in developping an analytical method, easy to implement in a QC laboratory for the determination of SG1 purity. The chosen analytical method has been developped by High Performances Liquid Chromatography (HPLC). This method requires the use of a standard sample of SG1, which has been obtained after purification of industrial batches of SG1 by the use of an innovative separative technology, the Centrifugal Partition Chromatography (CPC). The identification of the impurities, suspected as the major impurities in the industrial batches of SG1, has been carried out by NMR spectroscopy or by the study of their fragmentation observed by Tandem Mass Spectrometry – Electrospray Ionization. The use of these techniques enabled the identification of fifteen major impurities. Quantification methods by various techniques (HPLC-UV, HPLC-MS, GC-MS, other direct spectroscopic techniques like Infra-Red or other types of techniques like conductimetry) have been developped for twelve impurities

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4

Su, Hao-yuan, and 蘇澔元. "Identification of Major Impurities of Alachlor." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/pmjch6.

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碩士<br>朝陽科技大學<br>應用化學系碩士班<br>92<br>Beside of the active ingredient, there are six impurities which exceed the amount of 0.1% and have been found when the analytical technique of gas chromatography with flame ionization detector was used to analyze Alachlor herbicide. These impurities were named with impurity A to Impurity F for convenient identification. Gas chromatography combined with mass spectrometer was also used to identify these impurities in this study. The mass spectra of these impurities were compared with the NIST mass library to find out the possible matching chemicals for these impurities. The active ingredient was identified as Alachlor and the impurity A was identified as 2,6-diethylaniline. The other five impurities can’t be identified successfully with the NIST mass library. The possible structures of these impurities can be proposed by the mass spectra and the manufacturing process of Alachlor. Standard reference substance of impurity B was obtained from Sinon Corporation and be confirmed by means of the confirmation evidence obtained from the retention time of gas chromatography and the fragment ions of mass detection. Impurity C and impurity D were prepared by organic synthesis and were confirmed by NMR and FT-IR analysis. The chemical structures of impurity E and impurity F can’t be proposed as lack of sufficient information. Thus, the preparative HPLC purification technique was needed to obtain enough amounts of impurity E and impurity F. The analysis of both collected impurities was conducted by gas chromatography mass spectrometry. NMR spectra were accordingly to deduce their structures of impurity E and impurity F. As a result of this study, four major impurities of Alachlor were identified successfully. Impurity A was 2,6-diethylaniline. Impurity B was 2-Chloro-N-(2,6-diethylphenyl)acetamide. Impurity C was 2-Chloro-N-(2,6-di- ethylphenyl)-N-methylacetamide. Impurity D was 2,2-Dichloro-N-(2,6-diethyl- phenyl)-N-methoxymethylacetamide. Impurity E and impurity F are not totally confirmed due to the sample containing small amount of other unknown components. Impurity E was proposeded as N-(2-sec-Butyl-6-ethylphenyl)-2-chloro-N-methoxymethyl- acetamide. And impurity F was proposed as 2-Chloro-N-methoxy-methyl- N-(2,4,6-triethylphenyl)acetamide.

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Lee, Jun-sheng, and 李俊昇. "Identification of Major Impurities of Butachlor." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/gag6p7.

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碩士<br>朝陽科技大學<br>應用化學系碩士班<br>92<br>Beside of the active ingredient, there are six major impurities which exceed the amount of 0.1% and have been found when the analytical technique of gas chromatography with flame ionization detector was used to analyze Butachlor herbicide. These impurities were named with impurity I to impurity VI for easy identification. Gas chromatography with mass detector was used to identify these impurities in this study. The mass spectra of these impurities were compared with the NIST mass library to find out possible matching chemicals for these impurities. The exact matches include impurity I , impurity II and the active ingredient while the other four impurities can not be identified successfully with the NIST mass library. The possible structures of these impurities can be proposed from the fragments of mass spectra and the manufacturing process of Butachlor. Standard reference substance of impurity II was purchased from the vendor. Standard reference substance of impurity III was obtained from Sinon corporation and further confirmed the gas chromatography/mass spectrometry. Impurity I was prepared by organic synthesis route and the results were confirmed by gas chromatography with mass detector and NMR assay. The chemical structures of impurity IV, impurity V and impurity VI can not be proposed as lack of sufficient evidence and information. Thus the preparative HPLC purification technique was applied to get enough amounts of impurity IV, impurity V and impurity VI. The accuracy of these collected impurities were confirmed by gas chromatography with mass detector. NMR assay were applied subsequently to deduce the possible structures of impurity IV, impurity V and impurity VI. During the study works of this these, the six major impurities of Butachlor were identified successfully. Impurity I was Butyl chloroacetate. Impurity II was Dibutoxymethane. Impurity III was 2-Chloro-N-(2,6-diethyl-phen yl)-acetamide. Impurity IV probably was 2,2-Dichloro-N-butoxymethyl-N- (2,6-diethyl-phenyl)-acetamide. Impurity V probably was 2-Chloro-N-buto xymethyl-N-(2-sec-butyl-6-ethyl-phenyl)-acetamide. Impurity VI probably was 2-Chloro-N-butoxymethyl-N-(2,4,6-triethyl-phenyl)-acetamide.

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Books on the topic "Impurities identification"

1

Teasdale, Andrew. Genotoxic impurities: Strategies for identification and control. Wiley, 2011.

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Teasdale, Andrew. Mutagenic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2022.

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Teasdale, Andrew. Genotoxic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2011.

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Identification and Determination of Impurities in Drugs. Elsevier, 2000. http://dx.doi.org/10.1016/s1464-3456(00)x8001-5.

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Teasdale, Andrew. Mutagenic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2021.

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Görög, S. Identification and Determination of Impurities in Drugs. Elsevier Science & Technology Books, 2000.

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Teasdale, Andrew. Mutagenic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2021.

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Teasdale, Andrew. Genotoxic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2011.

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Teasdale, Andrew. Genotoxic Impurities: Strategies for Identification and Control. Wiley & Sons, Incorporated, John, 2010.

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Teasdale, Andrew. Mutagenic Impurities: Strategies for Identification and Control. Wiley & Sons, Limited, John, 2021.

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Book chapters on the topic "Impurities identification"

1

Dobo, Krista, Don Walker, and Andrew Teasdale. "Human Genotoxic Metabolites: Identification and Risk Management." In Genotoxic Impurities. John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470929377.ch6.

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Berberich, David W., Tao Jiang, Joseph McClurg, Frank Moser, and R. Randy Wilhelm. "Impurity Identification for Drug Substances." In Characterization of Impurities and Degradants Using Mass Spectrometry. John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470921371.ch8.

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Liu, David Q., Mingjiang Sun, and Lianming Wu. "Impurity Identification in Process Chemistry by Mass Spectrometry." In Characterization of Impurities and Degradants Using Mass Spectrometry. John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470921371.ch9.

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Hambly, David M., and Himanshu S. Gadgil. "Identification and Quantification of Degradants and Impurities in Antibodies." In Characterization of Impurities and Degradants Using Mass Spectrometry. John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470921371.ch13.

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Meyer, B. K., D. M. Hofmann, J. Stehr, and A. Hoffmann. "Spectral Identification of Impurities and Native Defects in ZnO." In Zinc Oxide Materials for Electronic and Optoelectronic Device Applications. John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119991038.ch6.

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Gu, Ming. "Isotope Patten Recognition on Molecular Formula Determination for Structural Identification of Impurities." In Characterization of Impurities and Degradants Using Mass Spectrometry. John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9780470921371.ch6.

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Mohan, Ganapathy. "Low Level Impurities in Drug Substances and Drug Products and the Analytical Challenges in Identification and Quantitation." In Pharmaceutical Stability Testing to Support Global Markets. Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-0889-6_16.

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"Identification and Control of Genotoxic Degradation Products." In Pharmaceutical Industry Practices on Genotoxic Impurities. CRC Press, 2014. http://dx.doi.org/10.1201/b17350-19.

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Görög, Sándor. "Preface." In Identification and Determination of Impurities in Drugs. Elsevier, 2000. http://dx.doi.org/10.1016/s1464-3456(00)80001-0.

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"List of contributors." In Identification and Determination of Impurities in Drugs. Elsevier, 2000. http://dx.doi.org/10.1016/s1464-3456(00)80002-2.

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Conference papers on the topic "Impurities identification"

1

Paudyal, Bijaya, Yo Han Yoon, David Cornwell, Phil Shaw, and Francisco Machuca. "Identification of metal impurities in crystalline silicon wafers." In 2012 IEEE 38th Photovoltaic Specialists Conference (PVSC). IEEE, 2012. http://dx.doi.org/10.1109/pvsc.2012.6317652.

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Harris, T. D. "Quantitative and Qualitative Determination of Impurities in III - V Semiconductors." In Laser Applications to Chemical Analysis. Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.tha6.

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Identification and determination of impurities in modern semiconductors is one of the most challenging analytical problems in materials characterization. Total impurity concentrations rarely exceed 100 parts per billion and the chemical state of the impurity is central to it's effect on semiconductor performance. The detection of these impurities is beyond almost all available analytical methods. Quantitative determination of these impurities is nearly impossible.

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Harris, T. D., and J. I. Colonell. "Quantitative Fluorescence Determination of Impurities in Compound Semiconductors." In Laser Applications to Chemical Analysis. Optica Publishing Group, 1990. http://dx.doi.org/10.1364/laca.1990.tub1.

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The electrical behavior of compound semiconductors is governed by the combined effects of the stoichiometry and impurities. The determination of impurity concentration in undoped samples is a largely unsolved problem. This deficiency results from the high purity routinely achieved in these materials, typically 1-20 ppb total impurity concentration, less than the detection limit of the applicable methods, such as SIMS. Progress toward quantitative impurity determination has been achieved by employing electronic Raman scattering, but this method is applicable only to acceptor concentration determination in bulk undoped semi-insulating GaAs. Low temperature luminescence methods have long been employed for impurity identification, but no attempt to quantify luminescence in direct gap semiconductors has been published, despite considerable success employing quantitative luminescence in Si.

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Moghaddam, Hossein Azizi, Farshid Mahmouditabar, and Ali Haghi. "Identification of Iron Powder B-H Characteristics Considering Impurities in the magnetic material." In 2019 10th International Power Electronics, Drive Systems and Technologies Conference (PEDSTC). IEEE, 2019. http://dx.doi.org/10.1109/pedstc.2019.8697726.

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Leandro S. Oliveira, Adriana S. Franca, and Vany P. Ferraz. "An analytical methodology for identification and quantification of common impurities in commercial roasted coffee." In 2001 Sacramento, CA July 29-August 1,2001. American Society of Agricultural and Biological Engineers, 2001. http://dx.doi.org/10.13031/2013.4054.

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Zamri, W. Wan Mohd, M. Muhammad Yasin, W. Wan Hashim, and A. Md Sani. "Breaking Barriers: Forging a Strategic Path for CCS Through Innovative Management of Other Contaminants Beyond CO2." In SPE Conference at Oman Petroleum & Energy Show. SPE, 2024. http://dx.doi.org/10.2118/218503-ms.

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Abstract Planning for CCS (Carbon Capture and Storage) development involves end-to-end evaluation from source to storage. When CCS is brought up as a topic, the conversation tends to center on managing CO2 (Carbon Dioxide). However, emission sources consist not only CO2, but also other contaminants and impurities such as H2S (Hydrogen Sulfide), SOx (Sulphur Oxide) and NOx (Nitrogen Oxide) and H2O (water). The origin of the emission determines the type of impurities present. For example. SOx and NOx only appears from post combustion sources but not from Acid Gas sources (recovered from the AGRU (Acid Gas Recovery Unit)), and H2S often present from Acid Gas source. These impurities are required to be manage in meeting the requirements of both subsurface (e.g. injectivity) and surface (e.g. technology limitation); in which will add to the process complexity, full cycle cost, HSSE (health, safety, security, environmental) risk, operational complexity, etc. Due to this fact, proper trade-off analysis needs to be conducted to generate the best end-to-end development scheme, whilst considering the suitable technologies to manage these impurities and their associated waste/by-product management. This development scheme should not only consider the type of emissions that it will initially handle but should also considers the future emission sources that plans to tie-in to it. Consideration should also be on the sequestration sites’ requirements since future sites may impose a different set of requirements (e.g. different acceptance of impurity concentration). It is then crucial to conduct project framing, concept identification, concept selection and storage site identification during the initial stage of the project. This paper shares a case study on the development of a CCS hub whilst discusses the approach taken to develop its end-to-end configuration and the consideration of available treatment technologies to manage its impurities thus meeting the transportation and sequestration requirements.

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Dutta, Debarati, Ravi Anand, and Anirban Sarkar. "Independently Operational Dual-Frequency Band Metamaterial Based EM Biosensor for Identification and Quantification of Impurities in Vegetable Oils." In 2023 IEEE SENSORS. IEEE, 2023. http://dx.doi.org/10.1109/sensors56945.2023.10325059.

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Radzig, Victor A. "The Point Defects with Low-Coordinated Si or Ge Atoms on Vitreous Silica Surface. Surface and Bulk Centers Comparison." In Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides. Optica Publishing Group, 1997. http://dx.doi.org/10.1364/bgppf.1997.jmd.3.

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Until recently, investigations of the surface and bulk defects in silica glass have developed virtually independent. Only in [1,2] some properties of the surface and bulk defects in vitreous silica were compared. Identification of the structure of defects in the bulk of silica glass is a considerably more complicated problem. This is explained by a wide variety of methods, which can be used to identify the structure of surface defects and reveal the mechanisms of their transformations under the action of different external factors (temperature, UV and γ-irradiation, reactions with different impurity molecules, the so-called technological impurities, etc.).

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de Villiers, Johan P. R., Noko Ngoepe, James Roberts, and Alison S. Tuling. "Evaluation of the Phase Composition, Crystallinity and Trace Isotope Variation of SiC in Experimental TRISO Coated Particles." In Fourth International Topical Meeting on High Temperature Reactor Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/htr2008-58208.

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The silicon carbide layers in experimental TRISO coated particles with zirconia kernels were evaluated for their phase composition, their impurity levels and the crystal perfection and twinning of the crystallites in the layers. This evaluation was necessary to compare the different SiC layers and to relate these properties to various quality tests and ultimately to manufacturing parameters in the CVD coater. Identification of the various polytypes was done using electron diffraction methods. This is the only method for the unequivocal identification of the different polytypes. The 3C, and 6H polytypes were positively identified. A feature of the SiC in some samples is the disordered nature of the phase. The disorder is characterised by planar defects, of different width and periodicity, giving rise to streaking in the diffraction pattern along the [111] direction of the 3C polytype. Polarised light microscopy in transmission is a useful tool to easily distinguish between the cubic (beta) and non-cubic (alpha) SiC in the layers. It also provides valuable information about the distribution of these phases in the layers. Raman spectroscopy was used to examine the distribution of Si in the SiC layers of the different samples. Two samples contain elevated levels of Si, of the order of 50%, with the highest levels on the inside of the layers. The elevated Si levels also occur in most of the other samples, albeit at lower Si levels. This was also confirmed by use of SEM electron backscatter analysis. Rietveld analysis using X-ray diffraction is presently the only reliable method to quantify the polytypes in the SiC layer. It was found that the SiC layer consists predominantly (82% to 94%) of the 3C polytype, with minor amounts of the 6H and 8H polytypes. Impurities in the SiC and PyC could be measured with sufficient sensitivity using laser ablation inductively coupled mass spectrometry (LA-ICP-MS). The SiC and PyC layers are easily located from the intensity of the C13 and Si29 signals. In most cases the absolute values are of less concern than the variation of impurities in the samples. Elevated levels of the transition elements Cu, Ni, Co, Cr and Zn are present erratically in some samples. These elements, together with Ag107 and Ag109, correlate positively, indicating impurities, even metallic particles. Elevated levels of these transition elements are also present at the SiC/OPyC (Outer Pyrolytic Carbon) interface. The reasons for this are unknown at this stage. NIST standards were used to calibrate the impurity levels in the coated particles. These average from 1 to 18 ppm for some isotopes.

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Duensing, Yannick, Oliver Richert, and Katharina Schmitz. "Investigating the Condition Monitoring Potential of Oil Conductivity for Wear Identification in Electro Hydrostatic Actuators." In ASME/BATH 2021 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fpmc2021-68818.

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Abstract To meet future goals of more electric airplanes conventional hydraulic airplane control systems, consisting of redundant centralized pumps within the airplane’s fuselage, need to be substituted for compact electro-hydraulic actuators (EHA). The capsulated architecture of EHAs results in higher safety due to separate hydraulic circuits, simple practicability of redundancy, decreased maintenance because of simplified error location detection as well as an overall reduction in weight and complexity of the airplane control system. Currently, EHAs are only used as backup devices as the reliability does not achieve normative requirements for a frontline application. Thus, recent studies aim to increase the reliability. The axial piston pump of current EHA is the source of most failures. High dynamic requirements and challenging operation points and environments result in wear of contact pairs such as swash plate/piston shoes, pistons/cylinder block and cylinder block/valve plate. In the scope of the project MODULAR at ifas one goal is to increase the robustness of the contact surfaces. A second goal addresses the topic of developing a condition monitoring approach to constantly track the pumps’ health status. Next to signals such as pressures and temperatures, acceleration and oil status signals describing the actual particle contamination are needed. In this contribution different methods of oil status detection are explained and the method of electric conductivity analysis for condition monitoring is further investigated. Filtered HLP46 is used and impurities in form of metallic powders are added. Furthermore, degraded oil of a disc-on-disc Tribometer test bench is measured and compared.

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