Degradation of wood constituents during the self-agglomeration of an oak sawdust. II. Infrared study of two lignins

1968 ◽  
Vol 46 (11) ◽  
pp. 1893-1902 ◽  
Author(s):  
Henry P. Naveau
Keyword(s):  
Aromatic Ring ◽  
Structural Changes ◽  
The Self ◽  
Infrared Spectrophotometry ◽  
Infrared Study

Structural changes in lignins isolated from particle-boards are studied by infrared spectrophotometry, in relation to an endothermic trend which characterizes the self-agglomeration process.Changes in intensity of various infrared bands are reported and are attributed to the following: (a) variation in the nature and distribution of substituents of the aromatic ring and conjugation of the aromatic ring with carbonyl C=O or C=C, which indicate an increasing state of condensation of the lignin, (b) simultaneous division of the macromolecule of lignin, partially caused by breakage of ether linkages between its lateral chains, (c) cleavage of bonds between lignin and carbohydrate material, and (d) insolubilization, with the acid lignin, of an increasing amount of carbohydrate material which is also increasingly condensed.The origin of the endothermic trend cannot be explained in terms of these reactions of lignin.

scholarly journals Gray-Matter Expansion of Social Brain Networks in Individuals High in Public Self-Consciousness

2021 ◽  
Vol 11 (3) ◽  
pp. 374
Author(s):  
Tomoyo Morita ◽  
Minoru Asada ◽  
Eiichi Naito
Keyword(s):  
Gray Matter ◽  
Structural Changes ◽  
Gray Matter Volume ◽  
Brain Networks ◽  
Japanese Version ◽  
Brain Regions ◽  
The Self ◽  
Social Brain ◽  
Default Mode ◽  
Public Self Consciousness

Self-consciousness is a personality trait associated with an individual’s concern regarding observable (public) and unobservable (private) aspects of self. Prompted by previous functional magnetic resonance imaging (MRI) studies, we examined possible gray-matter expansions in emotion-related and default mode networks in individuals with higher public or private self-consciousness. One hundred healthy young adults answered the Japanese version of the Self-Consciousness Scale (SCS) questionnaire and underwent structural MRI. A voxel-based morphometry analysis revealed that individuals scoring higher on the public SCS showed expansions of gray matter in the emotion-related regions of the cingulate and insular cortices and in the default mode network of the precuneus and medial prefrontal cortex. In addition, these gray-matter expansions were particularly related to the trait of “concern about being evaluated by others”, which was one of the subfactors constituting public self-consciousness. Conversely, no relationship was observed between gray-matter volume in any brain regions and the private SCS scores. This is the first study showing that the personal trait of concern regarding public aspects of the self may cause long-term substantial structural changes in social brain networks.

Hydrogen Release and Si-N Bond-Healing Infrared Study of Rapid Thermal Annealed Amorphous Silicon Nitride Thin Films

1995 ◽  
Vol 398 ◽  
Author(s):  
P. Santos-Filho ◽  
G. Stevens ◽  
Z. Lu ◽  
K. Koh ◽  
G. Lucovsky
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Gas Flow ◽  
Structural Changes ◽  
Thermal Dissociation ◽  
Chemical Vapor ◽  
Hydrogen Release ◽  
Ex Situ ◽  
Infrared Study ◽  
Amorphous Silicon Nitride

ABSTRACTWe address aspects of hydrogen bonding and its thermal evolution in amorphous Silicon nitride films grown by Remote Plasma Enhanced Chemical Vapor Deposition (RPECVD) from SiH4 and NH3 (or ND3) source gases. Rapid Thermal Annealing (RTA) decreases the Si-H(D) and SiN-H(D) bond populations. The hydrogen bonds break, and H2 (HD, D2) forms and evolves from the film with the heat treatment. This molecular hydrogen release is accompanied by Si- and N- bond healing as detected by a SiN infra red stretch mode signal gain. The ex-situ RTA experiment temperatures ranged from 400 °C to 1200 °C, in 100 °C steps and the film structural changes were monitored by Fourier Transform Infrared spectroscopy (FTIR) after each incremental anneal. Gas flow ratios R=NH3/SiH4 > 2 produced films in which SiN-H(D) bonds dissociated, and a gas desorption rate equation estimated an activation energy barrier of Ea = 0.3 eV. The release of hydrogen from the films in the form of H2 (D2) and ammonia radicals was detected by mass spectrometry and is shown here. The re-bonding of nitrogen to silicon upon thermal dissociation of hydrogen's is consistent with the improvement of the electrical properties of a-SiN:H films following RTA treatment.

Infrared study on the self-association of dimethyl sulfoxide

1966 ◽  
Vol 22 (4) ◽  
pp. 587-592 ◽  
Author(s):  
R.H. Figueroa ◽  
E. Roig ◽  
H.H. Szmant
Keyword(s):  
Dimethyl Sulfoxide ◽  
The Self ◽  
Infrared Study ◽  
Self Association

Formation of the first aromatic ring through the self-recombination of but-1-ene-3-yne with H-assistance in combustion

2016 ◽  
Vol 41 (31) ◽  
pp. 13736-13746 ◽  
Author(s):  
He Lin ◽  
Peng Liu ◽  
Zhenwu He ◽  
Yiran Zhang ◽  
Bin Guan ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
The Self

Infrared Studies of Oxygen-Containing Groups on the Surface of Carbon Black

1972 ◽  
Vol 45 (1) ◽  
pp. 106-116 ◽  
Author(s):  
M. L. Studebaker ◽  
R. W. Rinehart
Keyword(s):  
Carbon Black ◽  
Aromatic Ring ◽  
Chemical Reactivity ◽  
Infrared Study ◽  
Ring Type ◽  
Infrared Studies

Abstract Results of this infrared study give strong qualitative support for the presence of quinones and support the presence of lactones. Considerable chemical reactivity is associated with the presence of these two groups. Absorption typical of phenols and ethers was obtained in the 1205–1195 cm−1 and 1275-1265 cm−1 regions; and it is suggested by this study that the oxygen not present in quinone, lactone, or phenolic form is present as aromatic ring-type ether groups.

Infrared Study of Some Structural Changes in Natural Rubber during Vulcanization

1958 ◽  
Vol 31 (4) ◽  
pp. 719-736 ◽  
Author(s):  
Frederic J. Linnig ◽  
James E. Stewart
Keyword(s):  
Double Bond ◽  
Gamma Rays ◽  
Structural Changes ◽  
Elemental Sulfur ◽  
Carboxyl Groups ◽  
Double Bonds ◽  
Infrared Study ◽  
Tetramethylthiuram Disulfide ◽  
Vulcanized Rubber ◽  
Double Bond Shift

Abstract A knowledge of the structure of vulcanized rubber is essential to the interpretation of vulcanization and oxidation studies and the physical properties of the material. In the present work an infrared study has been made of structures resulting from a number of different methods of vulcanization. Sulfur vulcanizates show the presence of a shifted double bond, originally observed by Sheppard and Sutherland. The presence of conjugated double bonds is also indicated. Accelerators such as tetramethylthiuram disulfide and zinc dibutyl dithiocarbamate increase the rate of the double-bond shift and reduce the amount of conjugated double bonds. Neither the double-bond shift nor conjugation is observed as a result of vulcanization with tetramethylthiuram disulfide alone, hydrogen sulfide and sulfur dioxide (Peachey process), a peroxide, or gamma rays. These result in a possible decrease in carbonyl structures, and in the case of the last three, possible increased absorption due to OH and ionized carboxyl groups. Apparently, the double-bond shift and conjugation are primarily phenomena related to the use of elemental sulfur. The other vulcanization systems studied evidently involve different mechanisms. An implication of the present work is that there may be a relationship between the reported ease of oxidation of sulfur vulcanizates, accelerated vulcanizates, and sulfurless vulcanizates (tetramethylthiuram disulfide alone), which decreases in the order named, and the probable amount of conjugation in the compound, which decreases in the same order.

scholarly journals Employment Relationships in Dairy Farming - Psychological Contracts Reconsidered

1970 ◽  
Author(s):  
Rupert Tipples ◽  
Nona Verwood
Keyword(s):  
Structural Changes ◽  
Dairy Farming ◽  
Psychological Contracts ◽  
The Self ◽  
The Other ◽  
Common Denominator ◽  
Employment Relationships ◽  
Widespread Adoption ◽  
The Common

The essence of psychological contracting (in the contest of employment) is meeting mutual expectations. The common denominator between legal contracting and psychological contracting is that both are designed to express expectations of the self and of the other. Legal expectations lead to outcomes that are observable, measureable and usually quantifiable. Psychological expectations are usually invisible but nonetheless very real.This paper expresses the need for greater attentions to psychological contracting in a dairy sector going through substantial structural changes involving the replacement of self-employed farmers by hired managers and contract milkers and the widespread adoption of once-a-day milking.

Fourier transform infrared study of the self reaction of C2H5O2 radicals in air at 295 K

1989 ◽  
Vol 21 (11) ◽  
pp. 1077-1089 ◽  
Author(s):  
T. J. Wallington ◽  
C. A. Gierczak ◽  
J. C. Ball ◽  
S. M. Japar
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
The Self ◽  
Infrared Study
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