scholarly journals A Method for Accelerated Natural Weathering of Wood Subsurface and Its Multilevel Characterization

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 126
Author(s):  
Anna Sandak ◽  
Jakub Sandak ◽  
Marion Noël ◽  
Athanasios Dimitriou
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Degradation Process ◽  
Natural Weathering ◽  
Bordered Pits ◽  
Ft Ir ◽  
Short Time ◽  
Wood Surfaces ◽  
Kinetics Of

The function of altering weathering factors and degradation mechanisms are essential for understanding the weathering process of materials. The goal of this work was to develop a method for the acceleration of natural weathering and to investigate the molecular, microstructure and macrostructure degradation of wood caused by the process. Tests were performed in the whole month of July, which, according to previous research, is considered as the most severe for weathering of wood micro-sections. Sample appearance was evaluated by colour measurement. Scanning electron microscopy was used for evaluation of the structural integrity and changes in the microstructure of wood morphological components. Changes on the molecular level were assessed by means of FT-IR spectroscopy. Observation of the effects of weathering allowed a better understanding of the degradation process. Typical structural damage, such as cracks on bordered pits and cross-field pits, and, as a consequence, their erosion, revealed the sequence of the degradation process. It was confirmed that earlywood was more susceptible to damage than latewood. Even if the weathering test was conducted for a relatively short time (28 days) the ultra-thin wood samples changed noticeably. The progress of alteration was similar as usually noticed for wood surfaces, but occurred at shorter exposure times. The estimated acceleration factor was ×3, compare to the natural weathering kinetics of wood. The research methodology presented can be used for the determination of the weather dose-response models essential to estimate the future service life performance of timber elements.

scholarly journals Examination of steam gasification of coal with physically mixed catalysts

2019 ◽  
Vol 21 (4) ◽  
pp. 51-57 ◽  
Author(s):  
Katarzyna Śpiewak ◽  
Grzegorz Czerski ◽  
Agnieszka Sopata
Keyword(s):  
Coal Gasification ◽  
Steam Gasification ◽  
Conversion Degree ◽  
Process Time ◽  
Gasification Process ◽  
Kinetics Of Formation ◽  
Short Time ◽  
Kinetics Of ◽  
Positive Effect

Abstract The aim of this study was to analyse the steam gasification process of ‘Janina’ coal with and without Na-, K- and Ca-catalysts. The catalysts were physically mixed with the coal due to the simplicity of this method, short time of execution and certainty that the amount of catalyst is exactly as the adopted one. The isothermal measurements were performed at 800, 900 and 950°C and a pressure of 1 MPa using thermovolumetric method. The obtained results enabled assessment of the effect of analysed catalysts on the process at various temperatures by determination of: i) carbon conversion degree; ii) yield and composition of the resulting gas; and iii) kinetics of formation reactions of main gas components – CO and H2. The addition of catalysts, as well as an increase in operating temperature, had a positive effect on the coal gasification process – reactions rates increased, and the process time was reduced.

DEVELOPING OF MATLAB APPLICATION FOR DETERMINING THE REACTION KINETICS OF RUBBER VULCANIZATION PROCESS

2021 ◽  
Author(s):  
Dario Balaban ◽  
◽  
Jelena Lubura ◽  
Predrag Kojić ◽  
Jelena Pavličević ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Reaction Kinetics ◽  
Kinetic Parameters ◽  
Degradation Process ◽  
Complex Process ◽  
Quality Of Fit ◽  
Kinetics Of ◽  
Vulcanization Process

Rubber vulcanization is kinetically a complex process, since it consists of two simultaneous reactions: curing and degradation. To determine reaction kinetics, it is necessary to determine a kinetic model which describes the process adequately. Proposed kinetic model has six adjustable parameters. In order to determine kinetic parameters of the proposed kinetic model, commercially available rubber gum was used. Oscillating disc rheometer was used to investigate experimental dependence of torque on time, at six temperatures in the range from 130 to 180 °C, with a step of 10 °C. Matlab application, built via App Designer feature, was developed in order to fit the experimental data to the proposed kinetic model. Developed Matlab application, consisting of two tabs, enables user to upload raw rheometer data, perform manual fitting or automatic fitting (manual or automatic estimation of initial values of adjustable parameters), test the effect of constant values of some kinetic parameters on the overall quality of fit, visualize the dependence of kinetic parameters on temperature and to determine the values of Arrhenius expression for curing and degradation process. Both fitting methods were proven to be efficient; overall determination coefficient and MAPE value for automatic and manual fitting methods were >0.99 and <1%, and >0.999 and <1%, respectively. Arrhenius parameters were also determined with high accuracy (R2>0.98). Developed application enables simple and efficient determination of kinetic parameters by means of different fitting methods, simultaneous fitting of data on all temperatures, and testing the effect of constant kinetic parameters values on fitting results

scholarly journals Weathering Kinetics of Thin Wood Veneers Assessed with near Infrared Spectroscopy

2016 ◽  
Vol 24 (6) ◽  
pp. 549-553 ◽  
Author(s):  
Anna Sandak ◽  
Jakub Sandak ◽  
Ingunn Burud ◽  
Lone Ross Gobakken
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Degradation Process ◽  
Structural Members ◽  
Future Performance ◽  
Spectral Interpretation ◽  
Exposure Site ◽  
Kinetics Of

Wooden elements may be subjected to mechanical, environmental or biological alterations during their service life. The most susceptible parts of wood structural members are the exposed surfaces since they are subjected to ageing, weathering and/or decay. Knowledge of the influence of weathering factors and polymer degradation mechanisms is essential for understanding the weathering process of wood. The goal of this study was to investigate the degradation of thin wooden samples exposed to short-term weathering. Tests were performed through the European summer (July), which according to previous research is considered as the most severe period for weathering of wood micro-sections. Fourier transform near infrared spectroscopy was used for evaluation of chemical changes of wood samples. Three approaches for data evaluation are presented in this paper: (1) direct spectral interpretation, (2) a concept for calculation of a weathering index Wind and (3) kinetics of lignin changes in relation to the exposure direction for selected wavelengths. Observation of the effects of weathering will allow better understanding of the degradation process. The southern exposure site was slightly more affected by weathering than other sites. Results of this research will be used for future determination of the weather-dose response model and could be essential for predicting the future performance of timber facade elements.

scholarly journals Plasma Treatment Reduced the Discoloration of an Acrylic Coating on Hot-Oil Modified Wood Exposed to Natural Weathering

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 248 ◽  
Author(s):  
Arash Jamali ◽  
Philip D. Evans
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Water Vapour ◽  
Natural Weathering ◽  
Water Droplets ◽  
Acrylic Paint ◽  
Acrylic Coating ◽  
Bordered Pits ◽  
Wood Surfaces ◽  
Modified Wood

We test the hypothesis that plasma-treatment will remove oil from the surface of hot-oil modified blue-stained pine wood, and improve the adhesion and outdoor performance of a white acrylic coating on the modified wood. Modified wood was treated with water-vapour plasma, and microstructural changes at wood surfaces were examined. Plasma treatment removed oil from the surface of modified wood and etched bordered pits. The contact angle of water droplets on modified wood was 91.8°, but plasma-treatment for only 33 s reduced contact angle to less than that of the unmodified control (48.6°). The adhesion of the acrylic paint to modified wood was unaffected by plasma-treatment, but the adhesion rating of coated samples tested wet was slightly lower (3.1) than that of the coating on samples tested dry (3.5). The lightness value (CIE-L) of the acrylic coating on hot-oil modified wood samples exposed outdoors for 18 months was significantly lower (darker, 65.5) than that of the coating on similarly modified and exposed samples pre-treated with plasma (75.8). We conclude that plasma-treatment shows promise as a way of removing oil from the surface of hot-oil modified wood and reducing the discolouration of an acrylic coating on modified wood exposed to natural weathering.

scholarly journals CdS Loaded an Iranian Clinoptilolite as a Heterogeneous Catalyst in Photodegradation ofp-Aminophenol

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Alireza Nezamzadeh-Ejhieh ◽  
Khodarahm Shirvani
Keyword(s):  
Degradation Process ◽  
Optimal Operation ◽  
Primary Objective ◽  
Catalyst Loading ◽  
Thermal Methods ◽  
First Order Kinetics ◽  
Initial Ph ◽  
Ft Ir ◽  
Natural Clinoptilolite

Natural clinoptilolite, zeolite  CdS-incorporated  was prepared by ion exchange and precipitation procedures and it was characterized by FT-IR, XRD, and thermal methods. The prepared composite was used as a catalyst in the photodegradation process ofp-aminophenol in aqueous solution under UV irradiation. The effect of some key operating parameters such as catalyst dosage, temperature, the initial concentration of the pollutant, and initial pH of the solutions on the degradation process of the pollutant was studied. The primary objective was to determine the optimal conditions for each of the parameters. UV-vis spectrophotometric measurements were performed for the determination of degradation and mineralization extents. The optimal operation parameters were found as follows: pH 5, 17.5 mg·L−1of catalyst loading, and 10 ppm of dye concentration. The CdS particles out of zeolite framework do not show significant degradation efficiency. The degradation process obeyed first-order kinetics.

Determination of microbiological activity during the processing of frost damaged sugar beets

2014 ◽  
pp. 228-231 ◽  
Author(s):  
Maciej Wojtczak ◽  
Aneta Antczak-Chrobot ◽  
Edyta Chmal-Fudali ◽  
Agnieszka Papiewska
Keyword(s):  
Sugar Beet ◽  
Microbiological Activity ◽  
Microbiological Contamination ◽  
Sugar Beets ◽  
Bacterial Metabolites ◽  
Kinetics Of

The aim of the study is to evaluate the kinetics of the synthesis of dextran and other bacterial metabolites as markers of microbiological contamination of sugar beet.

Authentication of the Ancient Easel / Paintings Through Materials Identification from the Polychrome Layers II. Analysis by Means of the FT-IR Spectrophotometry

2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Irina Crina Anca Sandu ◽  
Constantin Luca ◽  
Ion Sandu ◽  
Viorica Vasilache ◽  
Mikiko Hayashi
Keyword(s):  
Degradation Rate ◽  
Animal Glue ◽  
Painting Materials ◽  
Ageing Rate ◽  
Ir Spectrophotometry ◽  
Private And Public ◽  
Ft Ir

This is the second paper belonging to a study concerning the authentication of ancient easel-paintings, on canvas and wood support, from private and public collections, by using the FT-IR spectrophotometry technique for the analysis of the painting materials. Different pigments, egg binders, caseins and animal glue, often found in ancient easel-paintings on wood or canvas, have been used as standards for establishing the ageing rate of the paintings by correlation with the dates presented in the first note. The determination of the degradation rate of the painting materials is an important archaeometric characteristic used in authentication.

Studies on the Behavior Some Paints in Electro-insulating Fluid Based on Vegetable Esters

2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus
Keyword(s):  
Structural Changes ◽  
Oxidation Processes ◽  
High Oleic ◽  
Painting Materials ◽  
Insulating Paper ◽  
Different Types ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Natural Ester

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.

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