Orientation and Degradation of Polymer Sliding Surfaces Evaluated by Raman Spectroscopy

2005 ◽  
Author(s):  
Pieter Samyn ◽  
Jan Quintelier ◽  
Patrick De Baets ◽  
Jeroen Van Craenenbroeck ◽  
Francis Verpoort ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
Case Studies ◽  
Functional Groups ◽  
Thermomechanical Analysis ◽  
Sliding Surface ◽  
Absorption Bands ◽  
Characteristic Absorption ◽  
Sliding Surfaces ◽  
Polyethylene Terephtalate

Present study investigates changes in the conformation of functional groups at the polymer sliding surface by postmortem Raman spectroscopy, thermomechanical analysis and SEM/EDX. Two case studies on sintered polyimide (SP) and thermoplastic polyethylene-terephtalate (PET) are presented, indicating the influences of sliding temperature, counterface type and internal lubricants (PET/PTFE) on some characteristic absorption bands in the Raman spectrum of the sliding surfaces.

scholarly journals Исследование структуры бивня мамонта методом ИК спектроскопии

2022 ◽  
Vol 130 (3) ◽  
pp. 369
Author(s):  
В.В. Павлова ◽  
Е.С. Петухова ◽  
Т.А. Исакова ◽  
Е.С. Колесова ◽  
А.А. Чириков ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Infrared Spectroscopy ◽  
Functional Groups ◽  
Ir Spectrum ◽  
Absorption Bands ◽  
Organic Part ◽  
Characteristic Absorption ◽  
Carbonate Anion

The structure of mammoth tusk was investigated by infrared spectroscopy, including after heat treatment. The whole complex of functional groups of the tusk components - hydroxyapatite, collagen and water - was revealed. It was found that collagen in the IR spectrum is represented mainly by characteristic absorption bands of amide and aliphatic groups. After heat treatment at 600 °C, the organic part is completely removed from the sample. It was found that hydroxyapatite in mammoth tusk is presented in a carbonate-substituted form, however, heat treatment at 900 °C leads to the removal of carbonate anion and water from the sample, which is accompanied by the transition of hydroxyapatite from the nonstoichiometric state to the stoichiometric state.

Interaction of tungsten in dry sliding against steel under high density electric current

2019 ◽  
pp. 101-109 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin ◽  
Yu. P. Mironov
Keyword(s):  
Electrical Contact ◽  
Analysis Data ◽  
Dry Sliding ◽  
Sliding Surface ◽  
X Ray ◽  
Sliding Surfaces ◽  
Quenched Steel ◽  
Sliding Electrical Contact ◽  
A Current ◽  
Tungsten Steel

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel. 

Robust sliding mode control for a class of underactuated systems with mismatched uncertainties

2009 ◽  
Vol 223 (6) ◽  
pp. 785-795 ◽  
Author(s):  
D W Qian ◽  
X J Liu ◽  
J Q Yi
Keyword(s):  
Robust Control ◽  
Sliding Mode Control ◽  
Control Method ◽  
Sliding Mode ◽  
Underactuated Systems ◽  
Sliding Surface ◽  
Nominal System ◽  
Sliding Surfaces ◽  
Mode Control ◽  
Mismatched Uncertainties

Based on the sliding mode control methodology, this paper presents a robust control strategy for underactuated systems with mismatched uncertainties. The system consists of a nominal system and the mismatched uncertainties. Since the nominal system can be considered to be made up of several subsystems, a hierarchical structure for the sliding surfaces is designed. This is achieved by taking the sliding surface of one of the subsystems as the first-layer sliding surface and using this sliding surface and the sliding surface of another subsystem to construct the second-layer sliding surface. This process continues till the sliding surfaces of all the subsystems are included. A lumped sliding mode compensator is designed at the last-layer sliding surface. The asymptotic stability of all of the layer sliding surfaces and the sliding surface of each subsystem is proven. Simulation results show the validity of this robust control method through stabilization control of a system consisting of two inverted pendulums and mismatched uncertainties.

FTIR and Raman spectroscopy characterization of functional groups in various rank coals

Fuel ◽  
2017 ◽  
Vol 206 ◽  
pp. 555-563 ◽  
Author(s):  
Xueqiu He ◽  
Xianfeng Liu ◽  
Baisheng Nie ◽  
Dazhao Song
Keyword(s):  
Raman Spectroscopy ◽  
Functional Groups ◽  
Ftir And Raman Spectroscopy

Raman Studies of the Adduct Structure of Cl2 and Br2 with Piaselenole

1980 ◽  
Vol 34 (6) ◽  
pp. 636-638
Author(s):  
J. J. Blaha ◽  
W. Brittain ◽  
C. E. Meloan ◽  
W. G. Fateley
Keyword(s):  
Molecular Structure ◽  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
Long Time

The affinity of 2,1,3-benzoselenadiazole, commonly called piaselenole, for chlorine and bromine molecules has been known for a long time. Raman spectroscopy provides a very interesting method for determining the molecular structure of these 1:1 adducts. The Raman spectrum shows the Cl2 and Br2 molecules in the adduct remain as a dimer molecule.

scholarly journals A surface confined yttrium(iii) bis-phthalocyaninato complex: a colourful switch controlled by electrons

2016 ◽  
Vol 7 (8) ◽  
pp. 4940-4944 ◽  
Author(s):  
I. Alcón ◽  
M. Gonidec ◽  
M. R. Ajayakumar ◽  
M. Mas-Torrent ◽  
J. Veciana
Keyword(s):  
Optical Properties ◽  
Absorption Bands ◽  
Electrical And Optical Properties ◽  
Redox States ◽  
Characteristic Absorption ◽  
Double Decker ◽  
Visible Spectra

SAMs of a Y(iii) double-decker complex on ITO have been prepared and their electrical and optical properties explored, exhibiting three accessible stable redox states with characteristic absorption bands in the visible spectra, corresponding to three complementary colors (i.e., green, blue and red).

scholarly journals Synthesis of ZnO and CuO nanoparticles via Sol gel method and Its Characterization by using XRD and FT-IR Analysis

2022 ◽  
Author(s):  
Monika Patel ◽  
Sunita Mishra ◽  
Ruchi Verma ◽  
Deep Shikha
Keyword(s):  
Particle Size ◽  
Zno Nanoparticles ◽  
Sol Gel ◽  
Broad Band ◽  
Zinc Nitrate ◽  
Zno Nanoparticle ◽  
Absorption Bands ◽  
Characteristic Absorption ◽  
Sol Gel Process ◽  
Ft Ir

Abstract Nanotechnology is a completely unique branch of technology that offers with substances in a very small size between (1-100 nm) with various crystal shapes which include spherical nanoparticles, flower shaped, Nano rods, Nano ribbons, and Nano platelets. Metals have ability to produce large number of oxides. These metal oxides play an major role in many areas of chemistry, physics, material science and food science. In this research, Zinc Oxide (ZnO) and Copper (II) oxide nanoparticles were synthesized via sol-gel process using zinc nitrate and copper (II) nitrate as precursor respectively. The characterization of CuO and ZnO nanoparticles was done by using various techniques. X-ray Diffraction (XRD) indicates the crystallinity and crystal size of CuO and ZnO nanoparticle. Fourier transform infrared spectroscopy (FT-IR) was used to get the infrared spectrum of the sample indicating composition of the sample which contains various functional groups. XRD result shows the particle size of CuO at highest peak 29.40140 was 61.25 nm and the particle size of ZnO at highest peak 36.24760 was 21.82 nm. FT-IR spectra peak at 594.56 cm-1 indicated characteristic absorption bands of ZnO nanoparticles and the broad band peak at 3506.9 cm-1 can be attributed to the characteristic absorption of O-H group. The analysis of FT-IR spectrum of CuO shows peaks at 602.09, 678.39, and 730.19cm−1 which refer to the formation of CuO. A broad absorption peak noticed at 3308.2 cm−1 attributed to O–H stretching of the moisture content.

scholarly journals Studying of 2D Titanium Carbide Structure by Raman Spectroscopy after Heat Treatment in Argon and Hydrogen Atmospheres

2017 ◽  
Vol 19 (2) ◽  
pp. 181 ◽  
Author(s):  
Olzhas Kaipoldayev ◽  
Ye. Mukhametkarimov ◽  
Renata Nemkaeva ◽  
G. Baigarinova ◽  
Madi Aitzhanov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Titanium Carbide ◽  
Functional Groups ◽  
Optimal Regime ◽  
Heat Treated ◽  
Initial Oxygen Content ◽  
Initial Oxygen ◽  
Tio2 Rutile ◽  
Total Disappearance

Herein we show the effect of heat treatment of two dimensional layered titanium carbide structure (Ti3C2Tx), so called MXene. As prepared MXene has functional groups -OH, -F, -Cl. In order to remove the functional groups we heat treated the MXene in Ar (with 0.01% O2) and H2 (with 0.01% H2O) atmospheres. We discovered the significant decrease in the amount of functional groups (-F and -Cl) and increase in the -O content, which refers to the oxidation of the material. Also we determined the optimal regime for Raman spectroscopy in order to avoid any changes in the structure of the material. We revealed that titanium carbide changes its structure at 700 °C and 900 °C into two different titanium dioxide modifications like rutile and anatase in Ar (with 0.01% O2) atmosphere. Also there are small changes occurred in Ti3C2Tx structure and formation of amorphous carbon after 700 °C treatment in H2 (with 0.01% H2O) atmosphere and formation of TiO2 (rutile) at 900 °C. Energydispersive X-ray spectroscopy (EDX) revealed the reduction of functional groups at 700 °C in both atmospheres and total disappearance of –F and –Cl and increasing the oxygen at 900 °C. The huge increase of oxygen by atomic percent, can be explained by the initial oxygen content in argon and hydrogen gases.

scholarly journals Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: method development for probabilistic modeling of organic carbon and organic matter concentrations

2020 ◽  
Vol 13 (3) ◽  
pp. 1517-1538
Author(s):  
Charlotte Bürki ◽  
Matteo Reggente ◽  
Ann M. Dillner ◽  
Jenny L. Hand ◽  
Stephanie L. Shaw ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Organic Matter ◽  
Organic Carbon ◽  
Functional Groups ◽  
Method Development ◽  
Estimation Method ◽  
Chemical Species ◽  
Monitoring Network ◽  
Ftir Spectra ◽  
Absorption Bands

Abstract. The Fourier transform infrared (FTIR) spectra of fine particulate matter (PM2.5) contain many important absorption bands relevant for characterizing organic matter (OM) and obtaining organic matter to organic carbon (OM∕OC) ratios. However, extracting this information quantitatively – accounting for overlapping absorption bands and relating absorption to molar abundance – and furthermore relating abundances of functional groups to that of carbon atoms poses several challenges. In this work, we define a set of parameters that model these relationships and apply a probabilistic framework to identify values consistent with collocated field measurements of thermal–optical reflectance organic carbon (TOR OC). Parameter values are characterized for various sample types identified by cluster analysis of sample FTIR spectra, which are available for 17 sites in the Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network (7 sites in 2011 and 10 additional sites in 2013). The cluster analysis appears to separate samples according to predominant influence by dust, residential wood burning, wildfire, urban sources, and biogenic aerosols. Functional groups calibrations of aliphatic CH, alcohol COH, carboxylic acid COOH, carboxylate COO, and amine NH2 combined together reproduce TOR OC concentrations with reasonable agreement (r=0.96 for 2474 samples) and provide OM∕OC values generally consistent with our current best estimate of ambient OC. The mean OM∕OC ratios corresponding to sample types determined from cluster analysis range between 1.4 and 2.0, though ratios for individual samples exhibit a larger range. Trends in OM∕OC for sites aggregated by region or year are compared with another regression approach for estimating OM∕OC ratios from a mass closure equation of the major chemical species contributing to PM fine mass. Differences in OM∕OC estimates are observed according to estimation method and are explained through the sample types determined from spectral profiles of the PM.

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