scholarly journals The IR Fourier spectroscopy of pine wood, struck with red belt fungus (Fomitopsis pinicola)

Author(s):  
В.А. Демин ◽  
Е.У. Ипатова ◽  
Л.М. Пахучая

Методом ИК Фурье спектроскопии в пределах одного ствола были изучены изменения древесины cосны обыкновенной (Pínus sylvéstris) в результате ее биологического поражения и деструкции окаймленным трутовиком – грибом Fomitopsis pinicola (Schw. ex Fr.) Karst. Исследование проводили на спектрометре Prestige-21 фирмы Shimadzu в области волновых чисел 4000– 400 см–1 с разрешением 4 см–1 (20 сканов). Спектры поглощения снимали с использованием приставки диффузионного отражения (ДО). Показано, что биодеструкция древесной ткани сосны отражается на ИК Фурье спектрах. Изменения наблюдаются в областях спектра поглощения, характеризующих валентные колебания гидроксильных, метиленовых, карбонильных групп, скелетные колебания ароматического кольца. Глубокая деструкция древесины в центре ствола сопровождается батохромным сдвигом (1734 см–1 до 1719 см–1) и значительным увеличением интенсивности полосы поглощения валентных колебаний карбонильных групп (1719 см–1), а также изменением контура спектра поглощения в области от ~1719 до ~1100 см–1. В спектре деструктированной древесины интенсивности полос поглощения в этой области уменьшаются, в спектрах образцов с периферии и центра ствола, сохранивших морфологическую структуру древесины – увеличиваются. В деструктированной древесине отмечено существенное увеличение интенсивности полосы поглощения при 1601 см–1, которая становится несколько большей, чем интенсивность полосы с максимумом 1508 см–1, что не характерно для ИК спектра здоровой хвойной древесины, в которой отношение интенсивностей этих полос поглощения противоположное. Сhanges of the Scots pine wood (Pínus sylvéstris) within a single tree trunk caused by its biological destruction made by red belt fungus Fomitopsis pinicola (Schw. ex Fr.) Karst were studied by use of the IR Fourier spectroscopy method. The wood was cut in Syktyvdin region of the Komi Republic. From the trunk about 36 сm in diameter a sample was sawed about 15 cm thick. Three samples were selected for spectra: 1 – light brown non-destructed wood from the centre of the trunk, 2 – dark brown, adjacent to the completely destroyed wood; 3 – from the periphery of the trunk not clearly affected by rot. The research was made by use of spectrometer Prestige-21 produced by Shimadzu company in the field of the wave numbers 4000–400 сm–1 with a resolution of 4 cm–1 (20 scans). Absorption spectra were examined by using a diffusion reflector (DR). It is shown that bio destruction of the wood fiber of pine is reflected on the IR Fourier spectra. Changes are observed in the absorption spectrum that characterize the valence oscillations of hydroxyl, methylene, carbonyl groups, and skeletal oscillations of the aromatic ring. A deep destruction of wood in the centre of the trunk is accompanied by a bathwater drift (1734 сm–1 to 1719 сm–1) and a significant increase in the absorption band of the valence oscillations of carbonyl groups (1719 сm–1), as well as change of the spectra contour of the absorption from ~1719 to ~1100 cm–1. In the spectrum of the disrupted wood, the intensity of the absorption bands in this area decreases, and in the spectra of the samples from the periphery and the center of the trunk that have preserved the morphological structure of the wood increases. There is a significant increase in the absorption band in the disrupted wood 1601 сm–1, that becomes bigger than, band intensity maximum 1508 сm–1, that is not typical for the IR spectrum of healthy coniferous wood, in which the ratio of the intensity of these absorption bands is the opposite.

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>


2021 ◽  
pp. 002199832110365
Author(s):  
Sônia MA Veroneze ◽  
Thais HS Flores-Sahagun ◽  
Ramón SC Paredes ◽  
Kestur Gundappa Satyanarayana

This paper presents a study about polypropylene-pine wood composites, both as filaments and products, coated with aluminum (Al) or copper (Cu), obtained through flame thermal spray process after subjecting the composites to thermal treatments in the second and third step of the study. Results revealed that a previous aluminum layer was needed in order to obtain copper coatings on the composites. The physical and mechanical properties of both metal coated composite filaments were also evaluated and compared with the uncoated composite filaments with and without heat treating these. Consequently, it was observed that the nature of the coating adhesion on the substrates was mechanical, and therefore abrasion blasting of filaments or the use of a higher wood fiber content in the composite improved the Al or Cu adhesion. Also, it was observed that extruded wood fiber/PP filaments should not be cooled in water because pieces might be molded directly once the moisture affects the metal coatings adhesion onto the substrates.


Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 833
Author(s):  
Edina Preklet ◽  
László Tolvaj ◽  
Eszter Visi-Rajczi ◽  
Tamás Hofmann

The goal of this research was the systematic study and comparison of the divided individual effects of UV light irradiation and water leaching during artificial weathering. Spruce (Picea abies Karst.) and Scots pine (Pinus sylvestris L.) samples were irradiated by ultraviolet (UV) light. Another sequence of samples was treated with the combination of UV irradiation and water leaching. The total extent of UV treatment was 20 days for both series of samples. Time relation of UV irradiation and water leaching was 2:1. The chemical changes were observed by FTIR spectroscopy. The difference spectrum was used for determination of the chemical changes. Degradation of lignin was greater for the leached samples than for the pure UV treated samples. Scots pine suffered greater lignin degradation than spruce, and produced higher absorption increase on the absorption region of unconjugated carbonyls. The unconjugated carbonyl groups were the most responsive chemical elements to leaching. Spruce was more susceptible to leaching of unconjugated carbonyl groups than Scots pine. Two absorption bands of unconjugated carbonyl groups at 1706 and 1764 cm−1 wavenumbers were produced by photodegradation. The absorption band at 1764 cm−1 was more sensitive to water leaching than the band at 1706 cm−1.


2019 ◽  
Vol 85 (4) ◽  
pp. 71-80
Author(s):  
Mariana Gumenna ◽  
Nina Klimenko ◽  
Alexandr Stryutsky ◽  
Alexandr Shevchuk ◽  
Viktor Kravchenko ◽  
...  

A method for the synthesis of reactive oligomeric silsesquioxanes, combining fragments of azo dye 4-(phenylazo)phenol and fluorescent dye Rhodamine B in various proportions in an organic shell was developed. These compounds were obtained by the reaction between the oligosilsesquioxane nanoparticles consisting of a mixture of linear, branched, ladder and polyhedral structures with epoxy groups in an organic frame (OSS–Ep) and the dyes. The structure of the synthesized substances was characterized by the methods of IR and 1H NMR spectroscopy. The UV-Vis spectra of OSS–Pp–Rh in DMF solution contain absorption bands characteristic of both acidic (560 and 350 nm) and lactone (in the range of 318–326 nm) forms of Rhodamine B. The absorption band of 4-(phenylazo) phenol fragments corresponding to π−π* transition is observed at 348 nm and overlaps the absorption band of Rhodamine B at 350 nm.The intensity of the absorption bands of fragments of various dyes depends on their content in organic frame of the silsesquioxane core. The intensity of the absorption bands at 348 nm and at 560 nm increases with an increase in the content of 4-(phenylazo)phenol and Rhodamine B correspondingly.It should be noted that when using DMF as a solvent the absorption band corresponding to acidic form of Rhodamine B at 560 nm in the UV-Vis spectra of the compounds obtained is more intense than similar band in the spectrum of the original Rhodamine B. Therefore, the attachment of Rhodamine B to the silsesquioxane core of oligomeric silsesquioxanes mixture does not have a significant effect on the position of absorption maxima in the UV-spectrum and prevents dye’s fragments from converting to the colorless lactone form. In the fluorescence spectra of OSS–Pp–Rh obtained using DMF as a solvent a peak at λ max = 592 nm (λex= 520 nm) is observed. The position of the fluorescence peak and its intensity in the spectra at the same optical density of the medium practically do not depend on the ratio of fragments of 4-(phenylazo)phenol and Rhodamine B in organic frame of OSS–Pp–Rh.  The combination of two different chromophores in organic shell of the silsesquioxane core broadens the range of absorbed light and the change of their ratio allows to adjust the absorption intensity in a certain area. The presence of hydroxyl groups makes it possible to introduce the obtained compounds into the composition of polymeric organic-inorganic nanocomposites by covalent bonding.


2019 ◽  
Vol 126 (2) ◽  
pp. 177
Author(s):  
И.Ю. Денисюк ◽  
К.Ю. Логушкова ◽  
М.И. Фокина ◽  
М.В. Успенская

AbstractMultilayer graphene has been obtained by ultrasonic splitting of graphite microparticles in a surface-active solvent that is a mixture of nonane and water and a surface-active surfactant, which provides dispersion of graphene in hydrophilic systems, has been selected. The chemical structure of the obtained materials has been investigated by IR Fourier spectroscopy. Possible mechanisms of the influence of inorganic surfactants (sodium liquid glass) on the graphene, the type of relations that arise between it and the graphene surface, and possible areas of its application have been discussed.


Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.


2021 ◽  
Vol 113 ◽  
pp. 36-42
Author(s):  
Barbara Białowąs ◽  
Karol Szymanowski

Effect of thermomechanical densification of pine wood (Pinus sylvestris L.) on cutting forces and roughness during milling. The paper presents the results of research concerning the assessment of machinability of pine wood thermomechanically compacted. The assessment was made on the basis of the cutting forces and surface roughness after the milling process. Selected properties of native and modified wood were examined. Based on the research, it was found that compacted wood is characterized by higher cutting forces during milling. The surface quality after milling was examined and the roughness index Ra values were determined. The research shows that the modified wood is characterized by a lower Ra value both along and across the grain. Statistical analysis showed that the modification had a statistically significant effect on the values of cutting forces and the physical and mechanical properties of the tested wood.


2020 ◽  
Vol 11 (4) ◽  
pp. 919-924
Author(s):  
G. A. Gorbacheva ◽  
A.V. Bazhenov ◽  
I. Shukhanova ◽  
V. G. Sanaev

2007 ◽  
Vol 62 (3-4) ◽  
pp. 205-212 ◽  
Author(s):  
Artem Kolobov ◽  
Vladimir Khokhlov ◽  
Alexei Potapov ◽  
Victor Kochedykov

Electronic absorption spectra of gaseous chlorine and their saturated solutions in molten alkali chlorides were studied in wide ranges of temperature and wavelength. It was found that gaseous chlorine has a wide absorption band between 20 000 and 43 500 cm−1. There is a tendency to both widening of the band and shifting of the absorption maximum to the short-waves region with rising temperature.The absorption bands of saturated solutions of chlorine in all molten alkali chlorides show a maximum in the neighborhood of 30 000 cm−1. A good correlation was found between the optical density of molten salt-Cl2 systems and the solubility of chlorine.


1972 ◽  
Vol 50 (6) ◽  
pp. 782-791 ◽  
Author(s):  
Eric A. Shaede

Radicals formed by γ-irradiation of propylene carbonate (PC) glasses at 77 °K were studied by e.s.r. and optical spectroscopy. Trapped electrons were identified by their narrow (ΔHms = 4.5 G) Gaussian e.s.r. line at g = 2.0028 which was completely resolved from the radical spectrum. The trapped electrons were unstable at 77 °K. They decayed fairly rapidly via a process exhibiting non-homogeneous kinetics believed to be reaction with positive ions. The temperature dependence of the e.s.r. spectra of the other radicals formed is discussed although conclusive assignment of the lines could not be made.Ultraviolet photolysis of the radicals in the irradiated PC glasses produced new species identified as HCO, CO3−, and CH3 by their characteristic e.s.r. spectra. In addition, a complex optical absorption band in the 500–750 nm region was assigned to a combination of the absorption bands of the CO3− radical anion and the HCO radical.


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