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23 pages, 11087 KiB

Open AccessArticle

Analysis of the Degree of Threat to Railway Infrastructure by Falling Tree Vegetation

by Michal Kučera and Zdena Dobesova

ISPRS Int. J. Geo-Inf. 2021, 10(5), 292; https://doi.org/10.3390/ijgi10050292 - 3 May 2021

Cited by 8 | Viewed by 2621

The article presents a method for determining and evaluating the threat to railway infrastructure from falling trees. The main objective was to identify the degree of threat according to three parameters: the height of tree stands, species composition, and vegetation health. Identification of the threat to individual railway sections would allow the creation of measures that could increase operational safety. Evaluation should be carried out at regular intervals to assess vegetation health during certain seasons. We, therefore, recommend the use of satellite images to provide a data source and regular data updates. The potential benefit is a reduction in railway infrastructure damage and an increase in traffic flow, especially during periods of exceptional weather conditions involving high wind, ice or heavy snow. The new method presented in the paper, based on data for railway infrastructure, law and other data sources in the Czech Republic, determines a Vegetation Threat Index for Railways (VTIR). We selected the Liberec Region as an example case study because of its large spread of wooded areas around railway lines and high incidence of railway traffic accidents. Full article

(This article belongs to the Special Issue GIS in Sustainable Transportation)

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17 pages, 4579 KiB

Open AccessReview

Structure and Stability of Gas Adsorption Complexes in Periodic Porous Solids as Studied by VTIR Spectroscopy: An Overview

by Montserrat R. Delgado

Appl. Sci. 2020, 10(23), 8589; https://doi.org/10.3390/app10238589 - 30 Nov 2020

Cited by 5 | Viewed by 2368

Abstract

Variable-temperature infrared (VTIR) spectroscopy is an instrumental technique that enables structural characterization of gas-solid adsorption complexes by analysis of meaningful vibrational modes, and simultaneous determination of the standard enthalpy change (ΔH⁰) involved in the gas adsorption process, which allows one to quantify the stability of the corresponding complex. This is achieved by a van’t Hoff analysis of a set of IR spectra recorded over a sufficiently large temperature range. Herein, the use of this versatile spectroscopic technique is demonstrated by reviewing its application to the study of carbon monoxide, carbon dioxide and dinitrogen adsorption on several (alkaline) zeolites, which can be regarded as the archetype of periodic porous solids. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

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10 pages, 2372 KiB

Open AccessArticle

Studying Proton Mobility in Zeolites by Varying Temperature Infrared Spectroscopy

by Pit Losch, Hrishikesh Joshi, Niklas Stegmann, Olena Vozniuk and Wolfgang Schmidt

Molecules 2019, 24(17), 3199; https://doi.org/10.3390/molecules24173199 - 3 Sep 2019

Cited by 4 | Viewed by 3020

Abstract

We report a varying temperature infrared spectroscopic (VTIR) study with partial deuterium isotopic exchange as a method for characterizing proton mobility in acidic materials. This VTIR technique permits the estimation of activation energies for proton diffusion. Different acidic materials comprising classical proton-conducting materials, such as transition metal phosphates and sulfonated solids, as well as different zeolites, are tested with this new method. The applicability of the method is thus extended to a vast library of materials. Its underlying principles and assumptions are clearly presented herein. Depending on the temperature ranges, different activation energies for proton transfer are observed irrespective of the different materials. In addition to the well-studied transition metal phosphates, Si-rich zeolites appear to be promising proton-transfer materials (with E_act < 40 kJ mol⁻¹) for application in high-temperature (>150 °C) PEM fuel cells. They significantly outperform Nafion and sulfonated silica, which exhibit higher activation energies with E_act ~ 50 and 120 kJ mol⁻¹, respectively. Full article

(This article belongs to the Special Issue Zeolites and Related Porous Materials: Design, Synthesis, and Applications)

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4027 KiB

Open AccessReview

Probing Gas Adsorption in Zeolites by Variable-Temperature IR Spectroscopy: An Overview of Current Research

by Edoardo Garrone, Montserrat R. Delgado, Barbara Bonelli and Carlos O. Arean

Molecules 2017, 22(9), 1557; https://doi.org/10.3390/molecules22091557 - 15 Sep 2017

Cited by 9 | Viewed by 6481

Abstract

The current state of the art in the application of variable-temperature IR (VTIR) spectroscopy to the study of (i) adsorption sites in zeolites, including dual cation sites; (ii) the structure of adsorption complexes and (iii) gas-solid interaction energy is reviewed. The main focus is placed on the potential use of zeolites for gas separation, purification and transport, but possible extension to the field of heterogeneous catalysis is also envisaged. A critical comparison with classical IR spectroscopy and adsorption calorimetry shows that the main merits of VTIR spectroscopy are (i) its ability to provide simultaneously the spectroscopic signature of the adsorption complex and the standard enthalpy change involved in the adsorption process; and (ii) the enhanced potential of VTIR to be site specific in favorable cases. Full article

(This article belongs to the Special Issue Zeolites and Related Nanoporous Materials: Synthesis, Characterization and Applications in Catalysis and Green Chemistry)

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