scholarly journals Influence of thermal treatment on color change of beech wood with red heartwood

2016 ◽  
pp. 239-256
Author(s):  
Nebojsa Todorovic ◽  
Zdravko Popovic ◽  
Goran Milic ◽  
Ranko Popadic
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Cross Section ◽  
Color Change ◽  
Beech Wood ◽  
Color Difference ◽  
Mean Values ◽  
Before And After ◽  
Section Surface ◽  
The Difference

The goal of this word was to examine the parameters of color of beech wood before and after thermal treatment, and to determine if there is a difference in color between sapwood and red heartwood before and after application of high temperature. Samples were treated at temperatures of 170?C, 190?C and 210?C, respectively, during 4 hours. Color coordinates (CIEL*a*b* system) were measured before and after treatment by using the following parameters: ?L, ?a, ?b and ?E - color change. Color was assessed at four spots on the radial and cross-section surfaces of wood and their mean values were taken for further calculations. Acquired results show that the applied heat treatment of sapwood did not significantly influence the change of color difference between cross-section and radial surfaces. The difference between cross-section and radial surfaces, in nontreated red heartwood was smaller than that measured in sapwood. The color difference of nontreated sapwood and red heartwood was more pronounced on the radial than on the cross-section surface. Application of high temperature caused a significant decrease of this difference. Temperature of 210?C caused the smallest color difference between these two parts of wood which was in this research determined on the radial surface. It was concluded that the applied thermal treatment almost equalized the colors of sapwood and red heartwood, especially on the radial surface, and from this aspect it can be concluded that these two parts of beech wood were completely equalized. It should also be noted that in the case of equalized properties, sapwood and red heartwood can be equally applied in a final product made of thermally treated beech wood.

scholarly journals Evaluation of the process thermal treatment of maple wood saturated water steam in terms of change of pH and color of wood

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2550-2559
Author(s):  
Ladislav Dzurenda ◽  
Anton Geffert ◽  
Jarmila Geffertová ◽  
Michal Dudiak
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Ph Value ◽  
Statistical Processing ◽  
Color Difference ◽  
Acer Pseudoplatanus ◽  
Water Steam ◽  
Saturated Water ◽  
Before And After ◽  
Total Color Difference

Changes in maple wood’s pH and color (Acer pseudoplatanus) were evaluated before and after thermal treatment process with saturated water steam. Maple wood was thermally treated at temperatures: tI = 105 ± 2.5 °C, tII = 125 ± 2.5 °C, and tIII = 135 ± 2.5 °C for τ ≤ 12 hours. Direct pH measurement of maple wood with a moisture content above the fiber saturation point (FSP) was performed using a pH-meter SI 600 with a Lance FET + H puncture probe. The polynomial dependence of pH and total color difference ∆E* on temperature t time τ was calculated by statistical processing of measured results. The correlation between the total color difference ∆E* of maple wood in the process of thermal color modification and the pH value is expressed y the equation: ∆E* = 4.5516∙(pH)2 – 48.405∙(pH) + 134.35. This dependence is a suitable tool for assessing the achieved color change based on the change of wood pH in the technological process.

scholarly journals Effect of Different Polishing Systems and Drinks on the Color Stability of Resin Composite

2013 ◽  
Vol 14 (4) ◽  
pp. 662-667 ◽  
Author(s):  
Sevil Gurgan ◽  
Asll Berber ◽  
Filiz Yalcin Cakir ◽  
Meserret Baseren
Keyword(s):  
Color Change ◽  
Resin Composite ◽  
Sour Cherry ◽  
Color Stability ◽  
Color Difference ◽  
Mean Values ◽  
Color Changes ◽  
Storage Solutions ◽  
Before And After ◽  
Cherry Juice

ABSTRACT Aim The purpose of this study was to evaluate the color stability of resin composit using different finishing systems and drinks. Materials and methods Composit disks (5 mm diameter, 2 mm thickness) were prepared for each nanofilled composite using a brass mold. The specimens were divided into 5 finishing system groups Mylar strip (Mylar, DuPont, Wilmington, Del., USA), Soft Lex (3M™ ESPE™ St. Paul, MN, USA), Enhance (Dentsply-DeTrey GmbHD Konstanz, Germany), Hiluster (KerrHawe, Bioggio, Switzerland), Opti Disc (KerrHawe, Bioggio, Switzerland) and each group was divided into 10 subgroups (n = 10) and stored for 24 hours at 37°C in different drinks water coffee, coffee with sugar, tea, tea with sugar, diet coke, coke, light sour cherry juice or sour cherry juice. Color of all specimens was measured before and after exposure with a spectrophotometer using CIE L*a*b* relative, and color changes (ΔE*) were then calculated. The data were analyzed with a twoway analysis of variance (ANOVA), and mean values were compared by the Tukey HSD test (p = 0.05). Results For the drinks, the lowest ΔE* values were observed in the water and highest ΔE* values were observed in sour cherry juice. When drinks with and without sugar were compared, all groups with sugar demonstrated a higher color difference than without sugar. For the different finishing systems, Mylar strip group demonstrated signicantly highest color change; Enhance groups demonstrated signicantly lowest color change. Conclusion Finishing treatments and storage solutions significantly affect the color stability of resin composite. The presence of sugar in drinks increased the color difference compared to drinks without composit. Clinical significance Polishing techniques and drinking drinks with sugar may affect the color of esthetic restorations. How to cite this article Berber A, Cakir FY, Baseren M, Gurgan S. Effect of Different Polishing Systems and Drinks on the Color Stability of Resin Composite. J Contemp Dent Pract 2013; 14(4):662-667.

scholarly journals Influence of Apical Patency and Cleaning of the Apical Foramen on Periapical Extrusion in Retreatment

2013 ◽  
Vol 24 (5) ◽  
pp. 482-486 ◽  
Author(s):  
Marili Doro Andrade Deonizio ◽  
Gilson Blitzkow Sydney ◽  
Antonio Batista ◽  
Roberto Pontarolo ◽  
Paulo Ricardo Bittencourt Guimarães ◽  
...  
Keyword(s):  
Material Removal ◽  
Filling Material ◽  
Mean Values ◽  
Filtration System ◽  
Root Canal Retreatment ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
The Difference ◽  
Removal Technique

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10–5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95±0.94), GIIM (0.47±0.62), GIPT (0.30±0.31) and GIIPT (0.32±0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

scholarly journals Comparison between Mobile Camera and DSLR Camera Photography for the Evaluation of Shade of Anterior Teeth - A Cross-Sectional Study

2019 ◽  
Vol 9 (2) ◽  
pp. 111-119
Author(s):  
Prabhat Shrestha ◽  
Sabina Poudel
Keyword(s):  
Mobile Phone ◽  
Color Difference ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Mean Values ◽  
Anterior Teeth ◽  
Mobile Cameras ◽  
Kappa Value ◽  
Acceptable Method ◽  
The Difference

 Background: Color accuracy plays a major role in creating an esthetic prosthesis. Photos taken with DSLR cameras have been the most frequent means of recording and transferring the color of teeth. Mobile phone cameras are emerging as a popular alternative to DSLR cameras due to its convenience. Our aim was to compare the color difference (ΔE) between the pictures taken with DSLR cameras and mobile cameras with and with­out using flash. Methods: Photos of right maxillary central incisors of patients (n=60) were taken with DSLR camera and mobile camera with and without using flash. The pictures were standardized with gray card and processed in Adobe Photoshop Lightroom CC software and the L*a*b* values of the pictures were compared to find the difference in color. Results: The percentage of agreement (ΔE≤2.7) for the difference of color between DSLR camera and mobile phone cameras without using flash (ΔE1) was 3.3% and with using flash (ΔE2) was 1.7%. The coefficient of agreement (using Kappa coefficient) between (ΔE1) and (ΔE2) showed total disagreement (kappa value =-.02). The mean values of ΔE1 was (8.3±3.3) and ΔE2 was (7.23±2.4). Conclusions: It was concluded that the color of mobile camera with or without using flash could not be considered as an acceptable method of recording color of teeth.

Artificial weathering of tropical woods. Part 2: Color change

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 558-565 ◽  
Author(s):  
Masanori Kishino ◽  
Takato Nakano
Keyword(s):  
Diffuse Reflectance ◽  
Color Change ◽  
Reflectance Spectra ◽  
Acacia Auriculiformis ◽  
Eucalyptus Marginata ◽  
Artificial Weathering ◽  
Diffuse Reflectance Spectra ◽  
Before And After ◽  
The Difference ◽  
Tropical Woods

Abstract This paper describes the change in diffuse reflectance Fourier transform infrared (DRIFT) and ultraviolet-visible (UV-Vis) diffuse reflectance spectra of the following eight tropical woods during artificial weathering up to 600 h in relation to their color changes, especially to yellowing: Amnurana acreana, Acacia auriculiformis, Dipterocarpus spp., Eucalyptus marginata, Eucalyptus robusta, Shorea spp. and Tabebuia spp. with relatively high and low specific gravity. For A. acreana, A. auriculiformis, Dipterocarpus spp. and both Tabebuia spp., Δb* (yellowing) increased with exposure up to 50 h, and decreased above 50 h. For E. marginata, E. robusta and Shorea spp., on the other hand, both Δa* (shift to red) and Δb* decreased with increased exposure time. For woods in which Δb* increased, the Δb* showed a positive dependence on the difference in relative intensity ratio of a band at 1740 cm–1 to that at 2900 cm–1 (ΔD1740/D2900) in DRIFT spectra of specimens before and after exposure. This result indicated that the increased band at 1740 cm–1 played a significant role in the increased Δb*. Then again, also for woods in which Δb* decreased, the ΔD1740/D2900 increased, but was not related to the Db*. The ΔD1740/D2900 for woods in which Δb* decreased had a positive relationship to the difference in remission function at 410 nm (ΔF(R∞)410) in UV-Vis diffuse reflectance spectra for specimens before and after exposure, while woods in which Δb* increased were independent of the ΔF(R∞)410. Therefore, it is suggested that woods in which Δb* increased and decreased differ from one another in the contribution to the increase in the band at 1740 cm–1, resulting in either an increase or decrease of Δb*.

Physical and electrical characterization of TiO2 particles after high temperature processing and before and after ultraviolet irradiation

2014 ◽  
Vol 92 (7/8) ◽  
pp. 832-837
Author(s):  
J. Molina ◽  
C. Zúñiga ◽  
M. Moreno ◽  
W. Calleja ◽  
P. Rosales ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Treatment ◽  
Uv Irradiation ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Electrical Characterization ◽  
Metal Electrode ◽  
Rutile Phase ◽  
Before And After ◽  
Diffraction Patterns

In this work, rutile-phase TiO2 particles (r-TiO2, about 360 nm in size) are embedded within a silicon oxide matrix using different concentration ratios of r-TiO2 with respect to SiO2:H2O, so that suspensions of mixed TiO2:SiO2 oxides were obtained and analyzed. These TiO2:SiO2 suspensions were deposited on previously-cleaned crystalline silicon and quartz substrates so that thin films of TiO2:SiO2 were obtained. All films were then exposed to relatively high-temperature thermal treatments in nitrogen and different characterization techniques were used to determine their physical and electrical properties before and after ultraviolet (UV) irradiation. Before high thermal treatment, X-ray diffraction patterns show that the main diffraction peaks for the obtained TiO2:SiO2 films correspond to the crystalline phase of rutile-TiO2. Infrared analyses before and after thermal treatment show significant changes in the chemical bonding of the final films relative to the temperatures used during annealing. Also, UV–visible spectra provide a constant optical band gap for the films, independent of different TiO2 concentrations as expected. On the other hand, atomic-force microscopy measurements before and after UV irradiation show an appreciable difference in the grain size and surface morphology of the resulting TiO2:SiO2 oxides annealed at 1000 °C. Finally, photoelectrical I–V properties were obtained for all TiO2:SiO2 films by depositing ultrathin titanium stripes on top of the photoactive material and then, measuring the total current flowing through the metal electrode before and after UV irradiation. From these last measurements, a detectable increase in the I–V slope (lower resistance of the titanium stripe) is found for all samples during UV exposure, thus making this device to act as a simple photoresistor based on r-TiO2 particles.

Dynamic Thermal Mechanical Behaviors and Mechanical Properties of Reversible Thermochromism Wood-Plastic Composite

2017 ◽  
Vol 727 ◽  
pp. 571-578
Author(s):  
Yue Qin Wen ◽  
Ying Ying Sun ◽  
Jian Feng Xu ◽  
Jing Bing Chen ◽  
Xin Xiang Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Color Change ◽  
Loss Modulus ◽  
Wood Plastic Composite ◽  
Advantages And Disadvantages ◽  
Plastic Composite ◽  
Before And After ◽  
The Difference ◽  
Reversible Thermochromism

To prepare a late-model and functional wood-plastic composite (WPC), the reversible thermochromism crystal violet lactone microcapsule was prepared by situ polymerization, then fabricated reversible thermochromism WPC by microcapsule and low density polyethylene with Maleic anhydride grafted polyethylene. Comparing the L, a and b data of apparent color of reversible thermochromism WPC, the value of chromatism (ΔE) showed the difference of heating before and after, it was also measured to characterize the color-change level; the mechanical properties of ordinary WPC and reversible thermochromism WPC were measured respectively to compare the advantages and disadvantages of two kinds of WPC; Then the storage modulus and loss modulus of ordinary WPC and reversible thermochromism WPC were determined to distinguish the good from the bad of two kinds of composites. The results indicated that the reversible thermochromism WPC is a functional composite with noticeable color-changed effects, and tensile strength, bending strength and interface compatibility were better than ordinary WPC, but had worse impact property contrarily.

scholarly journals Assessment of changes in color and color parameters of light-cured composite resin after alternative polymerization methods

2013 ◽  
Vol 07 (01) ◽  
pp. 110-116 ◽  
Author(s):  
Emine Sirin Karaarslan ◽  
Bulbul Mehmet ◽  
Ertas Ertan ◽  
Mehmet Ata Cebe ◽  
Aslihan Usumez
Keyword(s):  
Composite Resin ◽  
Color Change ◽  
Color Difference ◽  
Study Groups ◽  
Color Parameters ◽  
Color Changes ◽  
Yellow Color ◽  
Before And After ◽  
Total Color Change

ABSTRACTObjective:To examine the amount of change in color and color parameters of a composite resin (Filtek P60) polymerized by five different polymerization methods.Methods: A Teflon mold (6mm in diameter, 2mm in height) was used to prepare the composite resin discs (n=10). G1: Polymerization with inlay oven; G2: Polymerization with HQTH and autoclave; G3: Polymerization with LED and autoclave; G4: Polymerization with HQTH; G5: Polymerization with LED. Colorimetric values of the specimens before and after polymerization were measured using a spectrophotometer. The CIE L*a*b color system was used for the determination of color difference. Analysis of variance (ANOVA) was used to analyze the data for significant differences. Tukey’s HSD test and paired two-tailed tests were used to perform multiple comparisons (α=.05).Results: There were no significant differences in total color change (ΔE*ab) among the polymerization groups (P>.05). However, the lowest color change (ΔE*ab) value was 3.3 in LED and autoclave; the highest color change (ΔE*ab) value was 4.6 in HQTH. For all groups, CIE L*, C*ab and a*values decreased after polymerization (P<.05). The highest Δb* and ΔC*ab values were observed in specimens polymerized in an inlay oven (P<.05).Conclusion: Composite resin material showed color changes above the clinically accepted value in all study groups (ΔE*ab≥3.3). All specimens became darker during investigation (ΔL*< 0). Specimens polymerized with inlay oven presented the highest Δb* values which means less yellow color in specimens. (Eur J Dent 2013;7:110-116)

scholarly journals Effect of Different Bleaching Methods on Optical Behaviors of CAD/CAM Ceramics

2021 ◽  
Vol 13 (4) ◽  
pp. 113-118
Author(s):  
Saeed Nikanjam ◽  
Samaneh Abbasi ◽  
Sara Khazaei
Keyword(s):  
Hydrogen Peroxide ◽  
Significant Influence ◽  
Color Change ◽  
Mean Value ◽  
Carbamide Peroxide ◽  
Mean Values ◽  
Before And After ◽  
Cad Cam ◽  
The Mean ◽  
Final Color

Background: The present study aimed to survey the influence of two different bleaching techniques on changes of color, translucency, and whiteness of the four CAD/CAM materials. Methods: The monolithic blocks of Vita Suprinity, Vita Enamic, IPS e.max CAD, and Katana Zirconia were sectioned to discs with thickness of 2 mm (n=30 / each group). Samples from each type of ceramic were assigned to three subgroups: 1) the 40% hydrogen peroxide for 20 minutes; 2) the 16% carbamide peroxide for three hours/day for 2 weeks; and 3) the control. Then CIELab coordinates of each sample were evaluated before and after the intervention by a spectrophotometer. Final color change (ΔE), Whiteness (ΔWI D), and Translucency Parameter (ΔTP) were calculated. Two-way ANOVA test was adopted to analyze the data (α=0.05). Results: Type of ceramic, bleaching subgroups, and interaction between them had a statistically significant influence on mean values of ΔE, ΔWID. The influence of bleaching subgroup on the mean value of ΔTP was also significant (P<0.001). Conclusions: Carbamide peroxide 16% for three hours/day and for two weeks caused the most considerable changes in final color, whiteness, and translucency of the all tested CAD/CAM materials. Maximum color change and whiteness were detected in the Vita Enamic, which were clinically unacceptable.

scholarly journals The Influence of Short Duration Exercise on the Concentration of C-Reactive Protein and Selected Haematological and Biochemical Parameters in the Blood of German Shepherd Dogs

2017 ◽  
Vol 61 (2) ◽  
pp. 35-43 ◽  
Author(s):  
K. Goldírová ◽  
M. Fialkovičová ◽  
M. Benková ◽  
C. Tóthová ◽  
M. Harčárová
Keyword(s):  
Short Duration ◽  
Biochemical Parameters ◽  
C Reactive Protein ◽  
German Shepherd ◽  
Mean Values ◽  
Reactive Protein ◽  
Intensive Exercise ◽  
Before And After ◽  
The Mean ◽  
The Difference

Abstract Short-term intensive exercise may be associated with many short-lasting metabolic changes. These changes depend on the duration and intensity of the exercise. The aim of our study was to determine potential changes in C-reactive protein (CRP) and selected haematological and biochemical parameters in clinically healthy German shepherd dogs before short duration high-intensity exercise and 6 hours after the exercise. During the study, the dogs were subjected to the following defensive training: detaining a figurant running away from a dog (2×) and detaining with a counterattack (2×). The running distance was 200 m at a mean speed of 28 km.h-1. The investigation of haematological parameters revealed a significant decrease in the mean values of platelet haematocrit (PCT) 6 hours after the training. Significant differences in the levels determined before and after exercise were observed also for phosphorus (P) and for iron (Fe). At the same time, we observed a significant increase in the mean calcium (Ca) level and a significant decrease in sodium (Na) and chlorides (Cl). The activity of aspartate aminotransferase (AST) significantly increased after exercise. Concentrations of acute phase C-reactive proteins were increased 6 hours after exercise in comparison to those before exercise but the difference was insignificant. Although the concentration of CRP was increased insignificantly after the exercise, when interpreting concentrations of this nonspecific indicator of inflammation, one should keep in mind that intensive exercise may also affect its concentrations.

Sign in / Sign up

Export Citation Format

Share Document