scholarly journals Assessing the stability of alanine-based helices by conformer-selective IR spectroscopy

2016 ◽  
Vol 18 (29) ◽  
pp. 19950-19954 ◽  
Author(s):  
Waldemar Hoffmann ◽  
Mateusz Marianski ◽  
Stephan Warnke ◽  
Jongcheol Seo ◽  
Carsten Baldauf ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Gas Phase ◽  
Overall Stability ◽  
The Stability

Systematic amide-to-ester substitution suggests that a single backbone H-bond has only little influence on the overall stability of gas-phase α-helices.

ESTIMATING THE STABILITY OF METAL–LIGAND BONDING IN CARBOXYL-CONTAINING POLYMER COMPLEXES BY IR SPECTROSCOPY

2020 ◽  
Vol 61 (12) ◽  
pp. 1876-1887
Author(s):  
T. V. Berestova ◽  
K. N. Nosenko ◽  
O. V. Lusina ◽  
L. G. Kuzina ◽  
E. I. Kulish ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Polymer Complexes ◽  
The Stability ◽  
Metal Ligand

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

The influence of the chlorine-hydrogen ratio in the gas phase on the stability of the {113} faces of silicon in Si-H-Cl CVD

1990 ◽  
Vol 102 (1-2) ◽  
pp. 233-244 ◽  
Author(s):  
J.G.E. Gardeniers ◽  
M.M.W. Mooren ◽  
M.H.J.M. De Croon ◽  
L.J. Giling
Keyword(s):  
Gas Phase ◽  
The Stability

scholarly journals Discrimination of patterns of N-acetylation in chitooligosaccharides by gas phase IR spectroscopy integrated to mass spectrometry

2017 ◽  
Vol 89 (9) ◽  
pp. 1349-1357 ◽  
Author(s):  
Jasper Wattjes ◽  
Baptiste Schindler ◽  
Stéphane Trombotto ◽  
Laurent David ◽  
Bruno M. Moerschbacher ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ir Spectroscopy ◽  
Gas Phase ◽  
Dimensional Analysis ◽  
Unique Combination ◽  
Structural Detail ◽  
Chitosan Oligosaccharides ◽  
Infra Red ◽  
Rapid Discrimination ◽  
Gas Phase Spectroscopy

AbstractWe propose a novel, bi-dimensional analysis of partially N-acetylated chitosan oligosaccharides based on gas phase Infra-Red spectroscopy integrated to mass spectrometry (MS). By providing simultaneously MS and IR fingerprints, this approach combines the advantages of MS with the refined structural detail offered by gas phase spectroscopy and provides robust signatures for the rapid discrimination of the patterns of N-acetylation. Four mono-N-deacetylated and two doubly-N-deacetylated chitosan tetramer standards with well-defined patterns of acetylation were produced and analyzed by IR integrated to MS. We show that each sequence displays a unique combination of MS and IR fingerprints, thus offering a rapid diagnostic for the pattern of acetylation without the need for reducing end labeling.

scholarly journals SEA-BED CONFIGURATION IN RELATION TO BREAKWATER STABILITY

1972 ◽  
Vol 1 (13) ◽  
pp. 81 ◽  
Author(s):  
J.H. Van Oarschat ◽  
A. Wevers
Keyword(s):  
The Netherlands ◽  
Present Article ◽  
Water Depth ◽  
Systematic Study ◽  
Public Works ◽  
Irregular Waves ◽  
Sea Bed ◽  
Hydraulic Conditions ◽  
Overall Stability ◽  
The Stability

Stability tests on the Europoort breakwaters, situated on a shallow foreshore, clearly demonstrated the effect of the foreshore configuration on the overall stability. The present article gives a descriptionof the stability experiments and the interpretation leading to general conclusions regarding foreshore effects in combination with hydraulic conditions such as wave period, water depth and wave height. Both regular and irregular waves have been used. The experiments, carried out in commission of the Netherlands Government Department of Public Works (Rijkswaterstaat) were of an applied nature and were not directed primarily to the systematic study of foreshore effects.

scholarly journals The stability of major and trace element concentrations from musts to Champagne during the production process

OENO One ◽  
2022 ◽  
Vol 56 (1) ◽  
pp. 29-40
Author(s):  
Robin Cellier ◽  
Sylvain Berail ◽  
Ekaterina Epova ◽  
Julien Barre ◽  
Fanny Claverie ◽  
...  
Keyword(s):  
Trace Elements ◽  
Production Process ◽  
Trace Element ◽  
Narrow Range ◽  
Grape Juice ◽  
Elemental Concentrations ◽  
Element Concentrations ◽  
Production Processes ◽  
Overall Stability ◽  
The Stability

Thirty-nine Champagnes from six different brands originating from the AOC Champagne area were analyzed for major and trace element concentrations in the context of their production processes and in relation to their geographical origins. Inorganic analyses were performed on the must (i.e., grape juice) originating from different AOC areas and the final Champagne. The observed elemental concentrations displayed a very narrow range of variability. Typical concentrations observed in Champagne are expressed in mg/L for elements such as K, Ca, Mg, Na, B, Fe, A, and Mn. They are expressed in µg/L for trace elements such as Sr, Rb, Ba, Cu, Ni, Pb Cr and Li in decreasing order of concentrations. This overall homogeneity was observed for Sr and Rb in particular, which showed a very narrow range of concentrations (150 < Rb < 300 µg/L and 150 < Sr < 350 µg/L) in Champagne. The musts contained similar levels of concentration but showed slightly higher variability since they are directly influenced by the bedrock, which is quite homogenous in the AOC area being studied. Besides the homogeneity of the bedrock, the overall stability of the concentrations recorded in the samples can also be directly linked to the successive blending steps, both at the must level and prior to the final bottling. A detailed analysis of the main additives, sugar, yeast and bentonite, during the Champagne production process, did not show a major impact on the elemental signature of Champagne.

scholarly journals Catalytic Performance of Nitrogen-Doped Activated Carbon Supported Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol or Chloropentafluoroethane

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 674 ◽  
Author(s):  
Haodong Tang ◽  
Bin Xu ◽  
Meng Xiang ◽  
Xinxin Chen ◽  
Yao Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Liquid Phase ◽  
Gas Phase ◽  
Nitrogen Doping ◽  
Catalyst Surface ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Pd Catalyst ◽  
Nitrogen Doped ◽  
The Stability

Nitrogen-doped activated carbon (N-AC) obtained through the thermal treatment of a mixture of HNO3-pretreated activated carbon (AC) and urea under N2 atmosphere at 600 °C was used as the carrier of Pd catalyst for both liquid-phase hydrodechlorination of 2,4-dichlorophenol (2,4-DCP) and gas-phase hydrodechlorination of chloropentafluoroethane (R-115). The effects of nitrogen doping on the dispersion and stability of Pd, atomic ratio of Pd/Pd2+ on the surface of the catalyzer, the catalyst’s hydrodechlorination activity, as well as the stability of N species in two different reaction systems were investigated. Our results suggest that, despite no improvement in the dispersion of Pd, nitrogen doping may significantly raise the atomic ratio of Pd/Pd2+ on the catalyst surface, with a value of 1.2 on Pd/AC but 2.2 on Pd/N-AC. Three types of N species, namely graphitic, pyridinic, and pyrrolic nitrogen, were observed on the surface of Pd/N-AC, and graphitic nitrogen was stable in both liquid-phase hydrodechlorination of 2,4-DCP and gas-phase hydrodechlorination of R-115, with pyridinic and pyrrolic nitrogen being unstable during gas-phase hydrodechlorination of R-115. As a result, the average size of Pd nanocrystals on Pd/N-AC was almost kept unchanged after liquid-phase hydrodechlorination of 2,4-DCP, whereas crystal growth of Pd was clearly observed on Pd/N-AC after gas-phase hydrodechlorination of R-115. The activity test revealed that Pd/N-AC exhibited a much better performance than Pd/AC in liquid-phase hydrodechlorination of 2,4-DCP, probably due to the enhanced stability of Pd exposed to the environment resulting from nitrogen doping as suggested by the higher atomic ratio of Pd/Pd2+ on the catalyst surface. In the gas-phase hydrodechlorination of R-115, however, a more rapid deactivation phenomenon occurred on Pd/N-AC than on Pd/AC despite a higher activity initially observed on Pd/N-AC, hinting that the stability of pyridinic and pyrrolic nitrogen plays an important role in the determination of catalytic performance of Pd/N-AC.

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