scholarly journals Quantification of Carbonic Contamination of Fused Silica Surfaces at Different Stages of Classical Optics Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1620
Author(s):  
Robert Köhler ◽  
Domenico Hellrung ◽  
Daniel Tasche ◽  
Christoph Gerhard
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Decisive Role ◽  
Fused Silica ◽  
Process Step ◽  
Carbon Contamination ◽  
Silica Surfaces ◽  
Carbon Impurities ◽  
High Level ◽  
Glass Surfaces

The chemical composition of ground and polished fused silica glass surfaces plays a decisive role in different applications of optics. In particular, a high level of carbon impurities is often undesirable for further processing and especially for gluing or cementing where adhesion failure may be attributed to carbonic surface-adherent contaminants. In this study, the surface carbon content at different stages of classical optics manufacturing was thus investigated. Two different standard processes—grinding and lapping with two final polishing processes using both polyurethane and pitch pads—were considered. After each process step, the chemical composition and roughness of the surface were analysed using X-ray photoelectron spectroscopy and atomic force microscopy. An obvious correlation between surface roughness and effective surface area, respectively, and the proportion of carbon contamination was observed. The lowest carbon contamination was found in case of lapped and pitch polished surfaces.

scholarly journals Investigation of Non-Uniformity of Classically-Polished Fused Silica Surfaces via Laser-Induced Breakdown Spectroscopy

2019 ◽  
Vol 215 ◽  
pp. 08003
Author(s):  
Christoph Gerhard ◽  
Jörg Hermann
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Fused Silica ◽  
Laser Induced Breakdown Spectroscopy ◽  
Aluminium Content ◽  
Breakdown Spectroscopy ◽  
Silica Surfaces ◽  
Laser Induced Breakdown ◽  
High Aluminium

In this contribution, the surface uniformity of classically-manufactured fused silica windows was investigated via laser-induced breakdown spectroscopy. It is shown that for all investigated samples a comparatively high aluminium content was found at the edge of the surface with respect to its centre. This contamination can be attributed to residues from lapping and polishing agents and leads to a mentionable non-uniformity of the surface in terms of chemical composition and optical properties, respectively.

scholarly journals Degradation Products on Byzantine Glasses from Northern Tunisia

2020 ◽  
Vol 10 (21) ◽  
pp. 7523
Author(s):  
Valeria Comite ◽  
Martina Andreoli ◽  
Davide Atzei ◽  
Donatella Barca ◽  
Marzia Fantauzzi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Degradation Products ◽  
Morphological Structure ◽  
Sample Surface ◽  
Attenuated Total Reflection ◽  
Northern Tunisia ◽  
Icp Ms ◽  
Glass Surfaces

This study deals with the identification of the degradation products present on some Byzantine glasses coming from an archaeological excavation in Northern Tunisia. The main purpose of the present investigation is the identification of the products and the characterization of surface altered points, namely iridescent and black patinas, which are present on some selected glasses. Non-destructive techniques such as XPS (X-ray Photoelectron Spectroscopy), SEM-EDS (Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy), ATR-FTIR (Attenuated Total Reflection-Fourier Infrared Spectroscopy) and LA-ICP-MS (Laser-Ablation Inductively Coupled Plasma-Mass Spectrometry) are here exploited. SEM-EDS was employed to ascertain the morphological structure and the chemical composition of various points, apparently different, on the glass surfaces. Small area XPS was performed for identifying the elements present on the sample surface, for determining their chemical state and for establishing the atomic composition of the morphologically different regions. LA-ICP-MS was exploited to determine the chemical composition as far as the trace elements are concerned. The presence of iridescent patinas and of encrustations has been highlighted on the glass surfaces in correspondence to the altered areas: iridescent patinas are due to the fact that the glasses are depleted in alkali and alkaline earths. The incrustations resulted due to the presence of calcium carbonates, and/or oxyhydroxides. In one case sulfides were also detected by SEM.

scholarly journals Monitoring annealing via CO_2 laser heating of defect populations on fused silica surfaces using photoluminescence microscopy

2010 ◽  
Vol 18 (14) ◽  
pp. 15207 ◽  
Author(s):  
Rajesh N. Raman ◽  
Manyalibo J. Matthews ◽  
John J. Adams ◽  
Stavros G. Demos
Keyword(s):  
Laser Heating ◽  
Fused Silica ◽  
Silica Surfaces ◽  
Photoluminescence Microscopy

scholarly journals Chemical composition and toxicity of some Agro waste-derived insecticides against Angoumois grain moth, Sitotroga ceralella (Olivier) [Lepidoptera: Gelechiidae] infesting stored paddy grains

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Michael Olufemi Ashamo ◽  
Kayode David Ileke ◽  
Ayomiposi Idowu Onasile
Keyword(s):  
Chemical Composition ◽  
Adult Emergence ◽  
Adult Mortality ◽  
Agricultural Wastes ◽  
Sitotroga Cerealella ◽  
Angoumois Grain Moth ◽  
Egg Hatchability ◽  
Mortality Effect ◽  
Maize Cob ◽  
High Level

Abstract Background Agriculture being one of the major practices in the world has contributed to environmental pollution, especially in developing countries where there were no equipment to recycle the agricultural wastes. Considering the high level of infestation of paddy by Sitotroga cerealella and the high level of pollution caused by agricultural wastes, this research investigated the chemical composition and toxicity of agro wastes (rice husk, maize cob, groundnut and cowpea pods) as eco-friendly protectants of paddy against Sitotroga cerealella. Parameters assessed include adult mortality, oviposition, adult emergence and egg hatchability. Gas chromatography and mass spectrophotometry were used to isolate and characterize the active compounds present in the most effective crude extract. Results The results of the study revealed that all agricultural wastes showed high mortality effect on S. cerealella. Cowpea pod powder was the most toxic to adult paddy moth that caused 33.33%, 36.67%, 46.67%, 50% and 60% mortality of S. cerealella at concentrations 0.1 g, 0.2 g, 0.3 g, 0.4 g and 0.5 g/20 g of paddy grains after 24 h of exposure, respectively. The Cowpea pod, groundnut pod and maize cob extracts caused 100% mortality of S. cerealella at concentration 0.5 ml/20 g of paddy grains after 96 h of exposure, respectively. The lethal concentrations LC50 and LC90 of cowpea pod after 24 h were 0.16 and 0.64 ml which were the lowest of all agro waste extract tested. GC–MS analysis revealed that 19 chemical compounds were present in cowpea pod extract, 9, 12-Octadecadienoic acid (a methyl ester) has the highest percentage total of 39.57% and 4-Pentenal, 2-methylene (0.12%) has the least percentage total. Conclusion All the observations revealed that cowpea pod was the most effective. The findings also suggested that the selected agricultural wastes have a promising insecticidal potential and can be used as alternatives to synthetic chemical insecticides for the control of stored product insects.

scholarly journals Effect of Temperature on Corrosion Resistance of Layered Double Hydroxides Conversion Coatings on Magnesium Alloys Based on a Closed-Cycle System

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1658
Author(s):  
Xiaochen Zhang ◽  
Zhijuan Yin ◽  
Bateer Buhe ◽  
Jiajie Wang ◽  
Lin Mao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Conversion Coating ◽  
Effect Of Temperature ◽  
Conversion Coatings ◽  
Closed Cycle ◽  
Cycle System ◽  
Double Hydroxide ◽  
Double Hydroxides

The effect of temperature on the corrosion resistance of layered double hydroxide (LDH) conversion coatings on AZ91D magnesium alloy, based on a closed-cycle system, was investigated. Scanning electron microscopy (SEM), photoelectron spectroscopy (XPS), and X-ray diffractometry (GAXRD) were used to study the surface morphology, chemical composition, and phase composition of the conversion coating. The corrosion resistance of the LDH conversion coating was determined through electropotentiometric polarisation curve and hydrogen evolution and immersion tests. The results showed that the conversion coating has the highest density and a more uniform, complete, and effective corrosion resistance at 50 °C. The chemical composition of the LDH conversion coating mainly comprises C, O, Mg, and Al, and the main phase is Mg6Al2(OH)16CO3·4H2O.

scholarly journals Fermentation profile and chemical composition of cassava root silage

2021 ◽  
Vol 51 (3) ◽  
pp. 191-198
Author(s):  
Juliana Schuch PITIRINI ◽  
Rosana Ingrid Ribeiro dos SANTOS ◽  
Francy Manoely da Silva LIMA ◽  
Ilano Silva Braga do NASCIMENTO ◽  
Jehmison de Oliveira BARRADAS ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Dry Matter ◽  
Soil Acidity ◽  
Neutral Detergent Fiber ◽  
Fresh Matter ◽  
Cassava Root ◽  
Aerobic Stability ◽  
Fermentation Profile ◽  
Silage Production ◽  
High Level

ABSTRACT The use of cassava root silage for animal feeding is a suitable option for farmers who grow cassava as an alternative product and for cattle ranchers who have to deal with high prices of corn. Our objective was to determine the effects of cassava genotypes and the correction of soil acidity on the microbial population, fermentation characteristics, chemical composition, aerobic stability and losses of cassava root silage. We used a 2 × 3 factorial design in completely randomized blocks, with four replications. We evaluated two cassava genotypes (Caeté and Manteiguinha) and three methods of soil acidity correction (lime, gypsum, and lime+gypsum). The roots were harvested 11 months after planting, ensiled in PVC silos, and stored for 45 days. No interaction was observed between genotypes and soil acidity correction for any of the evaluated parameters. The silage of Caeté genotype showed the highest concentration of dry matter (421 g kg-1 fresh matter) and non-fibrous carbohydrates (893 g kg-1 dry matter), and the lowest concentrations of neutral detergent fiber (37.1 g kg-1 dry matter) . No significant differences were observed among treatments for lactic acid bacteria, yeast and mold counts in silages. Both genotypes resulted in silages with an adequate fermentation profile and considerably high aerobic stability, but with high effluent loss. The Caeté genotype showed to be potentially better for silage production due to its higher dry matter recovery. Due to the high level of effluent loss, it is recommended to test the effect of a moisture-absorbing additive during the ensiling process of these cassava roots.

scholarly journals Towards chemically neutral carbon cleaning processes: plasma cleaning of Ni, Rh and Al reflective optical coatings and thin Al filters for free-electron lasers and synchrotron beamline applications

2018 ◽  
Vol 25 (6) ◽  
pp. 1642-1649 ◽  
Author(s):  
Harol Moreno Fernández ◽  
Marco Zangrando ◽  
Guillaume Sauthier ◽  
Alejandro R. Goñi ◽  
Vincent Carlino ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Free Electron ◽  
Inductively Coupled Plasma ◽  
High Performance ◽  
Extreme Ultraviolet ◽  
Filter Material ◽  
Gas Mixture ◽  
Carbon Contamination ◽  
X Ray ◽  
Chemical Surface

The choice of a reflective optical coating or filter material has to be adapted to the intended field of application. This is mainly determined by the required photon energy range or by the required reflection angle. Among various materials, nickel and rhodium are common materials used as reflective coatings for (soft) X-ray mirrors. Similarly, aluminium is one of the most commonly used materials for extreme ultraviolet and soft X-ray transmission filters. However, both of these types of optics are subject to carbon contamination, which can be increasingly problematic for the operation of the high-performance free-electron laser and synchrotron beamlines. As an attempt to remove this type of contamination, an inductively coupled plasma source has been used in conjunction with N2/O2/H2 and N2/H2 feedstock gas plasmas. Results from the chemical surface analysis of the above materials before and after plasma treatment using X-ray photoelectron spectroscopy are reported. It is concluded that a favorable combination of an N2/H2 plasma feedstock gas mixture leads to the best chemical surface preservation of Ni, Rh and Al while removing the carbon contamination. However, this feedstock gas mixture does not remove C contamination as rapidly as, for example, an N2/O2/H2 plasma which induces the surface formation of NiO and NiOOH in Ni and RhOOH in Rh foils. As an applied case, the successful carbon removal from ultrathin Al filters previously used at the FERMI FEL1 using an N2/H2 plasma is demonstrated.

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