scholarly journals Drying of Steaming Maple Timber in Drying Kilns, While Preserving the Color Acquired by the Wood Steaming Process

2020 ◽  
Vol 328 ◽  
pp. 04004
Author(s):  
Ladislav Dzurenda
Keyword(s):  
Color Space ◽  
Free Water ◽  
Color Difference ◽  
Thermal Processes ◽  
Drying Process ◽  
Negative Aspect ◽  
Drying Time ◽  
Color Changes ◽  
The Difference ◽  
Total Color Difference

The paper presents a mode for drying steaming maple timber of thickness h = 38 mm from moisture W1 = 50 % to W2 = 10 %, while preserving the color of wood obtained by the steaming process. The drying process is divided into two parts. Evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and evaporation of water from wood below the hygroscopicity limit W ≤ 25 % at drying medium temperatures td = 70 - 80 °C. Total color difference ΔE* determined by the difference in values on the CIE L*a*b* color space coordinates dried by the proposed mode for steaming maple timber and the reference values ΔE* = 1.03. According to the categorization of wood color changes in thermal processes by work (Cividini et al. (2007), this change belongs to the category of small color changes. A negative aspect of this drying mode is the approx. 25 % increase in timber drying time.

Subjective Sensation of Color Differences – Determination of Thresholds Depending on Color Tones and Resolution

2015 ◽  
Vol 21 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Christian Brischke ◽  
Tanja Borcharding ◽  
Uta Mengel
Keyword(s):  
Color Space ◽  
Color Difference ◽  
Threshold Values ◽  
Color Tone ◽  
Color Changes ◽  
Art Objects ◽  
Color Differences ◽  
Subjective Sensation ◽  
Total Color Difference

Abstract Colors are frequently defined by three points on the L*a*b* coordinates of the CIELAB color space, and the distance between two colors can be expressed as the total color difference ΔE. In particular with respect to reproducibility of print media color differences are an important parameter, as well as for car finishes and textile dyes. Color changes are also the result of ageing and weathering which is an issue for art objects and in the building and restoration sector. However, the subjective perceptibility of color differences depends on numerous factors and general thresholds are difficult to define. This study aimed therefore on defining tolerance levels for color changes in dependence of color tones and color tone combinations as well as their resolution. In total 30 test persons evaluated samples, which had been painted with acrylic artist colors with defined color differences (ΔE = 0–7). The test subjects realized color differences already at ΔE = 1–4 for the highest resolution. Threshold values have been identified for different tones as well as the effect of interdependencies between tones and the level of color heterogeneity between adjacent areas.

Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam

2021 ◽  
Vol 116 ◽  
pp. 21-27
Author(s):  
Jakub Gawron ◽  
Monika Marchwicka
Keyword(s):  
Color Space ◽  
Color Difference ◽  
Thermal Modification ◽  
Fraxinus Excelsior ◽  
Space Model ◽  
Color Changes ◽  
Cielab Color Space ◽  
Before And After ◽  
Total Color Difference ◽  
Cielab Color

Color changes of ash wood (Fraxinus excelsior L.) caused by thermal modification in air and steam. Ash wood samples of 20x20x30 mm were subjected to thermal modification in different conditions. The thermal modification was conducted in air at 190 °C and in steam at 160 °C. For both environments modification lasted 2, 6 and 10 hours. Samples color parameters were measured before and after thermal modification on the basis of the mathematical CIELab color space model. Changes in all parameters (L, a and b) were observed, the highest in lightness (L) - darker color. The total color difference (ΔE) and chromaticity change (ΔC) were calculated for all samples. The highest value of ΔE was obtained for wood modified in the air at 190 °C for 10 h. The highest value of ΔC was obtained for wood modified in steam at 160 °C for 10 h. However, the value obtained for wood modified in the air at 190 °C for 10 h were only slightly lower.

scholarly journals Color Characteristics of Red False Heartwood and Mature Wood of Beech (Fagus sylvatica L.) Determining by Different Chromacity Coordinates

2019 ◽  
Vol 11 (3) ◽  
pp. 690 ◽  
Author(s):  
Ivan Klement ◽  
Tatiana Vilkovská
Keyword(s):  
Color Change ◽  
Free Water ◽  
Color Difference ◽  
Mature Wood ◽  
Affect Intensity ◽  
Drying Time ◽  
Color Changes ◽  
Hue Angle ◽  
Saturated Color ◽  
Different Color

Structure of wood can affect intensity of color change in remarkable ways. This article was focused on the analysis of the color changes red false heartwood and mature wood by different methods such as ΔE* (Total color difference), h* (Hue angle), C*ab (Color saturation) and Sab (Saturation). The aim of this study was to evaluate the color properties of red false heartwood and mature wood by using different chromacity coordinates. Our observations suggested that the density in the absolute dry state was equal between the red false heartwood and mature wood. The biggest difference was in the area of the free water domain, thus from an initial MC value to the fiber saturation point (FSP). The shorter drying time of the red false heartwood samples was caused by their lower initial MC. Due to the different MC, the temperature created a different color intensity of the compared samples. Mature wood samples achieved more saturated color in the drying process than did the samples of red false heartwood.

scholarly journals Optimization and Prediction of the Drying and Quality of Turnip Slices by Convective-Infrared Dryer under Various Pretreatments by RSM and ANFIS Methods

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Ebrahim Taghinezhad ◽  
Mohammad Kaveh ◽  
Antoni Szumny
Keyword(s):  
Energy Efficiency ◽  
Color Difference ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Diffusivity Coefficient ◽  
Drying Process ◽  
Anfis Model ◽  
Drying Time ◽  
Effective Moisture ◽  
Response Variables

Drying can prolong the shelf life of a product by reducing microbial activities while facilitating its transportation and storage by decreasing the product weight and volume. The quality factors of the drying process are among the important issues in the drying of food and agricultural products. In this study, the effects of several independent variables such as the temperature of the drying air (50, 60, and 70 °C) and the thickness of the samples (2, 4, and 6 mm) were studied on the response variables including the quality indices (color difference and shrinkage) and drying factors (drying time, effective moisture diffusivity coefficient, specific energy consumption (SEC), energy efficiency and dryer efficiency) of the turnip slices dried by a hybrid convective-infrared (HCIR) dryer. Before drying, the samples were treated by three pretreatments: microwave (360 W for 2.5 min), ultrasonic (at 30 °C for 10 min) and blanching (at 90 °C for 2 min). The statistical analyses of the data and optimization of the drying process were achieved by the response surface method (RSM) and the response variables were predicted by the adaptive neuro-fuzzy inference system (ANFIS) model. The results indicated that an increase in the dryer temperature and a decline in the thickness of the sample can enhance the evaporation rate of the samples which will decrease the drying time (40–20 min), SEC (from 168.98 to 21.57 MJ/kg), color difference (from 50.59 to 15.38) and shrinkage (from 67.84% to 24.28%) while increasing the effective moisture diffusivity coefficient (from 1.007 × 10−9 to 8.11 × 10−9 m2/s), energy efficiency (from 0.89% to 15.23%) and dryer efficiency (from 2.11% to 21.2%). Compared to ultrasonic and blanching, microwave pretreatment increased the energy and drying efficiency; while the variations in the color and shrinkage were the lowest in the ultrasonic pretreatment. The optimal condition involved the temperature of 70 °C and sample thickness of 2 mm with the desirability above 0.89. The ANFIS model also managed to predict the response variables with R2 > 0.96.

scholarly journals Impact of processing temperature on drying behavior and quality changes in organic beef

2018 ◽  
Author(s):  
Gardis J.E. Von Gersdorff ◽  
Luna Shrestha ◽  
Sharvari Raut ◽  
Stefanie K. Retz ◽  
Oliver Hensel ◽  
...  
Keyword(s):  
Moisture Content ◽  
Color Difference ◽  
Hyperspectral Data ◽  
Processing Temperature ◽  
Drying Process ◽  
Non Invasive ◽  
Beef Products ◽  
Drying Behavior ◽  
Increasing Demand ◽  
Total Color Difference

The drying of beef has gained an increasing interest and the organic market shows an increasing demand for dried beef products. In this study, organic beef meat slices were dried at 50 °C, 60 °C and 70 °C. Moisture content and color was measured throughout the drying process alongside Vis/VNIR hyperspectral images of the slices. The results of the total color difference (ΔE) showed the biggest change for samples dried at 50 °C (ΔE = 25.6). The aw value was the lowest for slices dried at 50 °C (0.744). The hyperspectral data gave promising results regarding non-invasive prediction of moisture content and color. Keywords: beef drying; drying behavior;color; hyperspectral imaging; quality.  

Evaluation of Microwave and Ozone Disinfections on the Color Characteristics of Iranian Export Raisins Through an Image Processing Technique

2019 ◽  
Vol 82 (12) ◽  
pp. 2080-2087
Author(s):  
REZA SADEGHI ◽  
ESMAEEL SEYEDABADI ◽  
RAHIL MIRABI MOGHADDAM
Keyword(s):  
Image Processing ◽  
Color Difference ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Storage Pests ◽  
Color Changes ◽  
Color Characteristics ◽  
Hue Angle ◽  
Total Color Difference ◽  
Ozone Treatments

ABSTRACT Raisins are one of the most important Iranian export products but are threatened by various storage pests. Because of the disadvantages of fumigants, we evaluated alternative microwave and ozone methods for their disinfection and the side effects on raisin qualities. To perform microwave disinfection, the studied raisin samples were exposed to microwave powers of 450, 720, and 900 W for 20, 30, 40, and 50 s. Also, ozone treatments included various combinations of ozone concentrations (2, 3, and 5 ppm) and exposure times (15, 30, 45, 60, and 90 min). An image processing technique was implemented to determine the color changes of raisins in terms of lightness, redness, yellowness, total color difference, chroma, and hue angle. The results revealed that increasing the microwave power and exposure time might lead to further changes of the previously mentioned color characteristics. Compared with the microwave treatments, ozone treatments had fewer effects on those features. Generally, microwave and ozone methods could successfully disinfect Oryzaephilus surinamensis in raisins, with acceptable changes in all the color characteristics. Hence, the previously mentioned methods are proposed as alternative chemical fumigants. HIGHLIGHTS

scholarly journals Design, Construction and Operation of Solar Dryer for Granules and Micros Chips of Manihot esculenta crantz Tuberous Roots

2015 ◽  
Vol 09 (2) ◽  
Keyword(s):  
Free Water ◽  
Logistic Function ◽  
Drying Process ◽  
Chi Square ◽  
Manihot Esculenta Crantz ◽  
Natural Laws ◽  
Limit Value ◽  
Tuberous Roots ◽  
Solar Drier ◽  
The Difference

This study presents the design details and the performance analyses carried out with Eloumah 1, the solar drier of cassava tuberous roots reduced in granules and microchips. Eloumah 1 is composed by a solar collector, a drying chamber and a box of rectangular section that joins the two previous components. In this solar drier the wet agricultural products are dried on the basis of the heat flux buoyancy that is induced by the difference in temperature and humidity in its compartments. Analyses of masses evaporated water of zizila and Obama (TME 419) granules and microchips tuberous roots varieties have been carried out in order to estimate the drying performance of Eloumah 1 and to know the natural laws of the drying process. The results show that Eloumah 1 is able to dry granules and microchiphs and to reduce their moisture contain to less than 10%. Moreover, it can be established that the drying process is a logistic process because in wet control samples, moisture contain has limited value. Therefore, the drying process cannot extract the free water beyond this limit value. The logistic function adjusts well these data based on the correlation coefficient (R2) and chi square coefficient (χ2).

scholarly journals ASSESSMENT OF FREEZING PRE-TREATMENTS FOR THE FREEZE DRIED OF APPLE SLICES

2013 ◽  
Vol 17 (2) ◽  
pp. 3-14 ◽  
Author(s):  
Tamás Antal ◽  
László Sikolya ◽  
Benedek Kerekes
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Color Difference ◽  
Freezing Rate ◽  
Slow Freezing ◽  
Drying Process ◽  
Drying Time ◽  
Freeze Dried ◽  
Apple Slices

Abstract The effect of freezing rate on the quality of dried Jonagold and Idared was studied. Apple slices underwent various pre-treatments, i.e. freezing in household freezer (freezing rate: 0,5 °C/min), contact plate freezing (2 °C/min) and vacuum-freezing (3 °C/min). The quality of the freeze dried product was then evaluated in terms of water activity, hardness, color and rehydration. The freezing in household freezer (slow freezing rate) significantly reduces the duration of the freeze drying process and consequently the process costs. The slow freezing rate allows the growth of large ice crystals at the beginning of the freeze-drying process, this fact should consequently lead to larger pores and injured cell walls and thus to shorter freeze drying time. Quality of the freezing in household freezer product was assessed as higher than the quality of the other freezing pre-treated material. Slow freezing rate resulted softer texture and higher rehydration capacity, than that of other pre-treated samples. In all cases, slow freezing lead to lower final moisture content, total color difference and water activity.

scholarly journals Artificial Neural Network Modeling of Drying Kinetics and Color Changes of Ginkgo Biloba Seeds during Microwave Drying Process

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jun-Wen Bai ◽  
Hong-Wei Xiao ◽  
Hai-Le Ma ◽  
Cun-Shan Zhou
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Ginkgo Biloba ◽  
Drying Kinetics ◽  
Microwave Drying ◽  
Drying Process ◽  
Drying Time ◽  
Color Changes ◽  
Rate Period ◽  
Artificial Neural

Ginkgo biloba seeds were dried in microwave drier under different microwave powers (200, 280, 460, and 640 W) to determinate the drying kinetics and color changes during drying process. Drying curves of all samples showed a long constant rate period and falling rate period along with a short heating period. The effective moisture diffusivities were found to be 3.318 × 10−9 to 1.073 × 10−8 m2/s within the range of microwave output levels and activation energy was 4.111 W/g. The L⁎ and b⁎ values of seeds decreased with drying time. However, a⁎ value decreased firstly and then increased with the increase of drying time. Artificial neural network (ANN) modeling was employed to predict the moisture ratio and color parameters (L⁎, a⁎, and b⁎). The ANN model was trained for finite iteration calculation with Levenberg-Marquardt algorithm as the training function and tansig-purelin as the network transfer function. Results showed that the ANN methodology could precisely predict experimental data with high correlation coefficient (0.9056–0.9834) and low mean square error (0.0014–2.2044). In addition, the established ANN models can be used for online prediction of moisture content and color changes of ginkgo biloba seeds during microwave drying process.

The Contribution of Co2+ to Blue Color of Synthetic Spinel

2011 ◽  
Vol 492 ◽  
pp. 400-403
Author(s):  
Ye Ma ◽  
Ying Guo
Keyword(s):  
Color Space ◽  
Measurement Instrument ◽  
Color Difference ◽  
Color Appearance ◽  
Color Measurement ◽  
Chemical Compositions ◽  
Blue Color ◽  
Color Changes ◽  
Specimen Processing ◽  
Relationship Of

Through to 110 pieces purity transparent and color uniform, 3 x 5 x 7mm blue synthetic spinel made with the flame fusion method on chemical compositions and color parameter measurement the Co2+ content and color changes, clear the influence on Co2+ relationship of blue synthetic spinels’ color appearance. Through LA-ICP-MS to analysis the cause of colorant content, proof that with Co2+, the increase of the content of synthetic spinel will shift blue to purple tone, and C* shows a parabola form with the drop of L*, 700 ppm ~ 900 ppm place in peak. DL* Î (3.55 ~ 76.94) with Co2+ Î (4.59 ppm ~ 1849 ppm) change the largest amount, DC* Î (-9.99 ~ 29.32) next, DH* Î (-20.34 ~ 4.67) compared with before two changes smallest. Co2+ content in 100ppm below, blue color of synthetic spinel with Co2+ content increased changes greatly; 500 ~ 1500 ppm, visually achieve optimal color (C* higher); above 1500ppm, because of the Co2+ overmuch make the color burn cause the overall decline of transparency, the change of L* tends to be gentle, C* decrease obviously. Use Color i5 in standard color measurement instrument lighting source D65, measured the lightness L*, specimen Color a* and b*, chroma C* and tonal angle ho, based on the uniform color space CIE 1976 L*a*b*, in lightness minimum L 9-10 specimen (processing data for standard to 9th), with the help of DE2000 benchmark for calculating formulas, the Color, the color difference train E* by partial correlation analysis card clearly degrees of off color changes L* has certain influence on rDL*×DE*= 0.996, while rDC*×DE*= -0.427, rDH*×DE*= -0.339. Conclusion, the bule color of synthetic spinel because of its Co2+ content changes main influencing L* to contribute to its color appearance.

Sign in / Sign up

Export Citation Format

Share Document