Studies on the suitability of oxidizing agents for discolouring lime and poplar wood in the first stage of transparent wood forming process

2019 ◽  
Vol 108 ◽  
pp. 148-155
Author(s):  
ANDRZEJ RADOMSKI ◽  
DARIA KAŹMIERCZAK
Keyword(s):  
Mass Loss ◽  
Sodium Chlorite ◽  
Poplar Wood ◽  
Alkaline Hydrogen Peroxide ◽  
Colour Space ◽  
Forming Process ◽  
Oxidizing Agents ◽  
Final Density ◽  
Colour Changes ◽  
Cie Lab

Studies on the suitability of oxidizing agents for discolouring lime and poplar wood in the first stage of transparent wood forming process. Series of lime and poplar wood samples were prepared and subjected to oxidising agent in order to decolourise wood in bulk. Sodium chlorite solution in the environment of diluted acetic acid and alkaline hydrogen peroxide solution were used as different treating agents, followed by intense rinsing in water and drying the samples. The effect of wood delignification conditions such as time of treatment and reagent used was investigated. Changes in mass and dimensions of the samples were measured, and thus density changes were calculated. Colour changes were measured with colorimeter in CIE Lab colour space. In the case of lime wood swelling of the samples was observed at the first stage, along with mass loss, leading to density decrease by 10 % after 20 h exposure. In the case of poplar wood, shrinking of the samples was observed, but due to severe mass loss, final density was similar to lime wood. Colour changes correlated mainly with lightness parameter of the samples. Significant colour differences were found even at the shortest time of treatment.

scholarly journals Isolation of Cellulose from Wheat Straw Using Alkaline Hydrogen Peroxide and Acidified Sodium Chlorite Treatments: Comparison of Yield and Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Umair Qasim ◽  
Zulfiqar Ali ◽  
Muhammad Shahid Nazir ◽  
Sadaf Ul Hassan ◽  
Sikander Rafiq ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Wheat Straw ◽  
Environmental Concerns ◽  
Sodium Chlorite ◽  
X Ray Diffraction ◽  
Alkaline Hydrogen Peroxide ◽  
X Ray ◽  
Multifunctional Material ◽  
Hydrogen Peroxide Treatment ◽  
Ft Ir

Environmental concerns due to excessive use of synthetic or petroleum-based materials have encouraged scientists to develop novel, sustainable, and multifunctional material using abundant lignocellulosic biomass. In this work, a study was conducted on the isolation of cellulose from wheat straw using two different methods: acidified sodium chlorite and alkaline hydrogen peroxide. A comparative study was carried out based on the yield and properties of extracted cellulose. The final product (after treatments) was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) for the identification of properties. Both the treatments isolated pure white color cellulose. However, the yield of cellulose isolated through acidified sodium chlorite treatment (81.4%) was higher than alkaline hydrogen peroxide treatment (79%). Moreover, no huge difference was observed in the crystallinity and thermal properties of extracted cellulose.

Effect of Ratio of Liquid Pigment on Colouring Cement Matrix

2019 ◽  
Vol 296 ◽  
pp. 3-8
Author(s):  
David Bujdoš ◽  
Lucia Bulíková
Keyword(s):  
Colour Change ◽  
High Ratio ◽  
General Definition ◽  
Cement Matrix ◽  
Future Research ◽  
Colour Space ◽  
Cement Mortars ◽  
Wide Range ◽  
Definition Of ◽  
Cie Lab

Nowadays, the colouring is used in wide range of architectural concrete. Therefore, determination efficiency of pigments in case of particular combination of input materials is necessary. The research deals with influence of concentration of liquid inorganic pigments on the resulting colour of cement mortars. Two liquid pigments (yellow, red) were used for measurement purposes to verify their optimal ratio to achieve the best colouring of cement specimens. Pigments were mixed in the mortars of two types of cements used for architectural and decorative design. The colour change was determined using Konica Minolta spectrophotometer in colour space CIE Lab (1976). General definition of deviation in the colour space ΔELab was applied for calculating of colour deviation. From the results of the laboratory tests is obvious that significant change of the colour of cement specimens do not show between the concentration of 6% and 9% of the pigment per cement weight yet. Consequently, using of high ratio of pigment than 9% is not profitable neither for purchaser, nor builder. Future research will focus on trials with a more elaborate share of pigment and it will have importance for price optimization in the construction industry.

scholarly journals Automatic CDR Estimation for Early Glaucoma Diagnosis

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
M. A. Fernandez-Granero ◽  
A. Sarmiento ◽  
D. Sanchez-Morillo ◽  
S. Jiménez ◽  
P. Alemany ◽  
...  
Keyword(s):  
Simple Structure ◽  
Spatial Information ◽  
Early Stage ◽  
Low Cost ◽  
Developed Countries ◽  
Colour Space ◽  
Screening Programs ◽  
Glaucoma Diagnosis ◽  
Initial Segmentation ◽  
Colour Changes

Glaucoma is a degenerative disease that constitutes the second cause of blindness in developed countries. Although it cannot be cured, its progression can be prevented through early diagnosis. In this paper, we propose a new algorithm for automatic glaucoma diagnosis based on retinal colour images. We focus on capturing the inherent colour changes of optic disc (OD) and cup borders by computing several colour derivatives in CIE L∗a∗b∗ colour space with CIE94 colour distance. In addition, we consider spatial information retaining these colour derivatives and the original CIE L∗a∗b∗ values of the pixel and adding other characteristics such as its distance to the OD centre. The proposed strategy is robust due to a simple structure that does not need neither initial segmentation nor removal of the vascular tree or detection of vessel bends. The method has been extensively validated with two datasets (one public and one private), each one comprising 60 images of high variability of appearances. Achieved class-wise-averaged accuracy of 95.02% and 81.19% demonstrates that this automated approach could support physicians in the diagnosis of glaucoma in its early stage, and therefore, it could be seen as an opportunity for developing low-cost solutions for mass screening programs.

Colour variation in standard soil-colour charts

Soil Research ◽  
2005 ◽  
Vol 43 (7) ◽  
pp. 827 ◽  
Author(s):  
M. Sánchez-Marañón ◽  
R. Huertas ◽  
M. Melgosa
Keyword(s):  
Analysis Of Variance ◽  
Colour Difference ◽  
Colour Space ◽  
Perception Threshold ◽  
Colour Variation ◽  
Standard Soil ◽  
Colour Changes ◽  
Cielab Colour

This paper presents colourimetric analyses of 6 standard soil-colour charts (1372 chips) from different manufacturers, editions, and degrees of use. The CIELAB hab, L*, and C*ab were found to have significant (analysis of variance, P < 0.05) variations among tested charts, and the Munsell hue, value, and chroma measured in most chips varied from their notation by as much as 1 unit. This discrepancy can be attributed to printing differences and/or colour fading. The Munsell loci of constant hue and chroma plotted in CIELAB colour space showed that colour fading is not uniform, so that visual steps between neighbouring chips change, and constant hue and chroma lines become deformed. The colour difference between chips identically designated in two charts ranged from 0.94 CIEDE2000 units (above perception threshold) for charts from the same manufacturer and degree of use, to 3.72 CIEDE2000 units for old charts from 2 different manufacturers. Chips from old charts became yellowish, darker, and less saturated. These colour changes are consistent with the responses of 10 observers who, on assessing 10 soil-colour samples, reported Munsell notations to have redder hue, lighter value and greater chroma. Periodic colourimetric checking of soil-colour charts would be advisable in order to avoid mistakes in soil-colour description.

Effects of lignin content and acid concentration on the preparation of lignin containing nanofibers from alkaline hydrogen peroxide mechanical pulp

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Lulu Zhu ◽  
Shiwen Xue ◽  
Hao Ren ◽  
Jin Zhao ◽  
Huamin Zhai ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Lignin Content ◽  
Raw Material ◽  
Sodium Chlorite ◽  
Fiber Morphology ◽  
Alkaline Hydrogen Peroxide ◽  
Mechanical Pulp ◽  
Chemical Pulp ◽  
Nano Cellulose

AbstractThe poplar alkaline hydrogen peroxide mechanical pulp (APMP) with the lignin content of 24.63 % was used as raw material, which with lignin content of 10.04 %, 6.33 %, 3.82 %, and 1.14 % were obtained by the acid sodium chlorite method for 1–4 hours respectively. Then, different lignin content APMP were micro-nano processing treated with acidolysis (6.5 M, 9.8 M) or ultra-granular grinding respectively. Afterwards, poplar bleached chemical pulp (BCP) was prepared micro-nano cellulose under the same conditions as the APMP. Then, compared the data of the particle size, specific surface area, fiber morphology and zeta potential of suspensions between micro-nano cellulose products. The results show that the presence of a small amount of lignin (1–4 %) in APMP does not affect the preparation of different scales nano cellulose under different acid concentration conditions. When the lignin content is reduced to below 2 %, the acidolysis is more uniform, stable, and well-dispersed compared to BCP products; when the APMP is processed by the ultra-granular grinding, the higher lignin content, the more obvious cutting effect in the fiber length direction. The characteristics and feasibility of the preparation of micro-nano cellulose by the acidolysis and ultra-granular grinding using APMP with varying degrees of delignification are compared.

scholarly journals Colour modifications and hyperspectral imaging: non-invasive analysis of photo-degraded wood surfaces

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Giorgia Agresti ◽  
Giuseppe Bonifazi ◽  
Luca Calienno ◽  
Giuseppe Capobianco ◽  
Angela Lo Monaco ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Solar Irradiation ◽  
Poplar Wood ◽  
Chemical Modifications ◽  
Non Invasive ◽  
Cielab System ◽  
Colour Changes ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Wood Surfaces

The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to solar irradiation, in a controlled environment. Poplar is poor of coloured extractive, so that the surface changes are attributed to the main wood constituents’ modifications and the contribution of extraneous substances to holocellulose and lignin can be considered negligible. The poplar wood samples were irradiated in a Solar Box chamber, equipped with a 280 nm UV filter, until reaching 504 hours. The colour changes were monitored with the reflectance spectrophotometer of X-Rite CA22 according to the CIELAB system. The surface chemical modifications were evaluated by measuring the infrared spectra with a Fourier Transform Infrared spectrometer (FT-IR) operating in DRIFT modality. Hyperspectral imaging (HSI) was also applied to study the surface wood changes by using a SisuCHEMA XL Workstation operating in the SWIR range (1000-2500 nm). The data obtained from the different techniques applied were put in comparison in order to find possible correlations between them also with the aim to evaluate the applicability of the HSI technique to the investigation of wood modifications, in a totally non-invasive modality. The possibility to find a correlation between colour changes and chemical modifications, investigated both with traditional and innovative methodologies, in wood surfaces can have practical application in cultural heritage and contemporary objects.

scholarly journals Colour analysis of syrup from malted and unmalted rice of different varieties

2020 ◽  
Vol 12 (1) ◽  
pp. 130-138 ◽  
Author(s):  
Chijioke Maduka Osuji ◽  
Chigozie Emmanuel Ofoedu ◽  
Gloria Chienyenwa Omeire ◽  
Moses Ojukwu
Keyword(s):  
Visible Region ◽  
Colour Difference ◽  
Colour Space ◽  
Brown Colour ◽  
Significant Difference ◽  
Hue Angle ◽  
Hydrolyzing Enzymes ◽  
Cie Lab ◽  
Starch Hydrolyzing Enzymes ◽  
Colour Chart

The colour of rice syrup produced from flours of malted and unmalted rice of different varieties treated with a combination of starch hydrolyzing enzymes were analysed using CIE-LAB Spectrophotometric colorimeter after being filtered and/or centrifuged. The resulting syrups were processed as filtered unmalted hydrolyzed rice (FUHR), filtered malted hydrolyzed rice (FMHR), centrifuged unmalted hydrolyzed rice (CUHR) and centrifuged malted hydrolyzed rice (CMHR). Results showed that L* ranged from 60.16 to 68.57, a* ranged from 10.49 to 11.13 and b* ranged from 55.34 to 64.56. The magnitude of the colour values was an indication of the intensity of the rice syrup colour. Hue angle (oH*) ranged from 79.08o to 80.36o indicating less yellow in the CIE-LAB colour space and brown colour spectrum in the visible region of opponent colour chart. Total colour difference (ΔE) of syrups ranged from 0.50 to 1.72 for ΔEunmalted while ΔEmalted ranged from 0.49 to 1.76. However, the ΔEfiltered ranged from 5.89 to 11.19 while ΔEcentrifuged ranged from 5.54 to 9.47 indicating that filtration and centrifugation contributed to non-significant difference (p&gt;0.05) in colour attributes (ΔE) of the rice syrup, whereas very distinct colour difference (ΔE) was observed between rice syrups from malted and unmalted samples.

Initial studies on the influence of Aspergillus niger on the wood components of Populus sp.

2020 ◽  
Vol 110 ◽  
pp. 140-147
Author(s):  
Ewa Lisiecka ◽  
Anna Lesiak ◽  
Jan Szadkowski ◽  
Dominika Szadkowska ◽  
Andrzej Radomski ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Growth Conditions ◽  
Wood Chips ◽  
Spore Suspension ◽  
Sodium Chlorite ◽  
Poplar Wood ◽  
Chemical Analyses ◽  
Structural Components ◽  
Wood Degradation ◽  
Degree Of Degradation

Initial studies on the influence of Aspergillus niger on the wood components of Populus sp. An attempt was made to determine the content of structural substances (cellulose, holocellulose, lignin) and non-structural substances in poplar wood (Populus sp.) infected with the mentioned fungus. For this purpose, wood chips were infected with spore suspension and then incubated under sterile and suitable growth conditions. After 7, 14 and 21 days the degree of poplar wood degradation was assessed by determining the substances contained in the wood by performing chemical analyses: Kürschner-Hoffer cellulose, holocellulose by the sodium chlorite method, lignin in accordance with PN-92/P50092 standard and non-structural components. The conducted analyses made it possible to determine the effect of Aspergillus niger’s presence time on the degree of degradation of individual wood components.

Investigation of fungal decay of poplar wood treated with pistachio resin

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 779-788
Author(s):  
Maede Ahadnezhad ◽  
Soheila Izadyar ◽  
Davood Efhamisisi
Keyword(s):  
Mass Loss ◽  
Trametes Versicolor ◽  
Populus Deltoides ◽  
Treated Wood ◽  
Brown Rot ◽  
White Rot ◽  
White Rot Fungus ◽  
Poplar Wood ◽  
Fungal Decay ◽  
Brown Rot Fungus

The density, swelling, and fungal decay of poplar (Populus deltoides) wood treated with pistachio resin (PR) obtained from Pistacia atlantica were investigated. The white-rot fungus Trametes versicolor and the brown-rot fungus Coniophora puteana were used. Methanolic solutions of PR with different concentrations of 1%, 6%, 12%, and 15% were used as the preservative solution. Wood samples were saturated by two different vacuum/pressure (V/P) and dipping methods. The density, volumetric swelling of treated wood, and their mass loss (ML) caused by fungal decay were determined. The density of treated species increased to 15.4% and 5.8% for V/P and dipping methods, respectively, at 15% PR concentration. The volumetric swelling of the treated samples was reduced to 24.5% and 16.8% for V/P and dipping procedure, respectively, at 15% PR concentration. The mass loss of treated samples after exposure to T. versicolor was less than the untreated one (17.4% for V/P and 22.6% for dipping methods at 15% PR concentration). The results showed the better performance of V/P treatment in promotion of wood durability against fungal decay than the dipping method.

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