Artificial neural network approach for protection of the color of dried golden and pink oyster mushrooms with pretreatments

In this study, the possibilities of protecting the color of dried golden and pink mushrooms were investigated, and color parameters of dried mushrooms were modeled by artificial neural network (ANN). For this purpose, first, the golden oyster mushroom (Pleurotus citrinopileatus) and pink oyster mushroom (Pleurotus djamor) were cultivated. Then, pretreatments were applied using citric acid (CA) and potassium metabisulfite (KMS) with different rates (0.5%, 1.0%, and 1.5%) separately, excluding control group mushrooms. All mushrooms were dried for 330 minutes in a laboratory type oven at two different temperatures (40°C and 50°C) until completely dehydrated. Colorimetric values (L*, a*, and b*) were determined using Konica Minolta CM‐2600d spectrophotometer for 30 minute intervals during the drying process. The obtained data were modeled using the ANN technique. The results show that darkening of mushrooms increased as the drying temperature increased. CA and KMS showed better results for dried golden and pink mushrooms, respectively. Thanks to the pretreatment, the mushroom's original color was protected compared with control samples. All mean absolute percentage error values of models were determined, which were lower than 4.0%. It was concluded that ANN can be a good way to predict the color of dried golden and pink mushrooms (pretreated or not) with a high degree of accuracy.     

Novel methods for dyeing the epidermis of bamboo culms and their colour fastness

This study examined the effects of various dyestuffs and treatment conditions on the epidermis colour of ma bamboo (Dendrocalamus latiflorus), moso bamboo (Phyllostachys pubescens), and makino bamboo (P. makinoi). The objective was to determine the optimum approach for endowing the bamboo culms with a fascinating brown colour without removing their epidermis, which would increase the economic value of bamboo products. Experimental results revealed that an excellent brown colour was obtained when bamboo culms were treated with 0.25% CI Basic Brown 4 solution in an 80 °C water bath for 60 min (H° values of 37.9, 25.0, and 25.7° respectively). In addition, alkali‐pretreated bamboo culms also exhibited a good brown colour dyeing when treated with 0.25% CI Basic Brown 4 at ambient temperature for 2 days (a* and b* values of 30.8 and 35.1 respectively). Furthermore, the use of an ultrasonic bath instead of a water bath can reduce the treatment time required for achieving an improvement in the effectiveness of brown colour dyeing of the bamboo epidermis. Results obtained from indoor light fastness tests demonstrated that more uniform dyeing and better colour fastness could be achieved by colour fixation post‐treatment with 1% glacial acetic acid.     

Dyeing treatments for protecting colour and colour fastness of green bamboo culms

The effects of various dyestuffs and treatment conditions on the epidermis colour of ma bamboo (Dendrocalamus latiflorus), moso bamboo (Phyllostachys pubescens), and makino bamboo (P. makinoi) were examined to determine the most appropriate dyeing material and approach for endowing bamboo culms with a fascinating green colour without removal of their epidermis. Experimental results revealed that excellent green colour was obtained when the three species of bamboo culms were treated with 0.25% basic dyes in an 80 °C water bath for 30 min (a* values of −19.6, −15.4, and −16.0, respectively). Moreover, alkali pretreatment, though contributing to dyeing effectiveness, yielded bamboo culms with dim surface lightness of low L* values. Dye makino bamboo culms without colour fixation post-treatment changed from green to light green after indoor exposure for 1 year, exhibiting unstable indoor colour fastness. In contrast, colour fixation post-treatment was found to improve colour fastness of bamboo culms; in particular, treatment with 1% glacial acetic acid or 3% tannic acid achieved more uniform dyeing effectiveness and better indoor fastness. By inhibiting discoloration, the natural beauty of bamboo culm can be preserved and its service life can be extended.     

Synthesis and characterization of Y (In,Mn) O3 blue pigment using the complex polymerization method (CPM)

In this paper, a new synthetic pathway is proposed for the system YIn_1-xMn_xO₃, a bright blue inorganic pigment, discovered in 2009. Blue pigment samples with increasing concentration of Mn³⁺ (x?=?0.08, 0.12 and 0.16) were prepared using the complex polymerization method (CPM) and compared with those synthesized via solid state reaction. All powders, the amorphous precursor from CPM and the starting materials for solid state method, were calcined at 1000, 1100, 1200 and 1300?°C for 12?h, and the resulting blue pigments were characterized by X-ray diffraction (XRD), colorimetric system CIE L*a*b* and Near infrared (NIR) reflectance measurements. XRD patterns and Rietveld Refinement show that the lowest temperature at which single hexagonal phase (isostructural to YInO₃) is formed is 1000?°C for CPM method and 1300?°C for conventional solid state method, respectively. The L*a*b* values demonstrate that the coloration of powders prepared by CPM exhibit temperature dependence below 1300?°C, a color shade shift from grayish blue to intense deep blue is observed when heating the samples from 1000 to 1300?°C. Blue pigments obtained by CPM have smaller particle size due to low temperatures and excellent near-infrared reflectance comparable to those by solid state method. Thus, providing advantages for application process and energy efficiency.     

Effect of Steam Heating on the Color and Chemical Properties of Neosinocalamus Affinis Bamboo

Abstract

Fibrous veneers in loose structure were made from Neosinocalamus affinis bamboo, and then used as the basic element for bamboo-based fiber composites. Steam treatment of the fibrous veneers was performed inside an autoclave at 0.35 MPa to 0.45 MPa (147°C to 155°C) for 110 min to 170 min. After steam treatment, all three color parameters (L*a*b*) of fibrous veneers were changed significantly. The color change (ΔE*) increased with higher pressure and longer duration. The chemical properties of steam-treated samples were examined using chemical analysis. A decrease in the content of holocellulose and α-cellulose with an elevation in steam treatment was found. The water extractives content and buffering capacity increased, and the effect of pressure and duration on them increased significantly. pH value decreased significantly compared with control samples, but only small variations were found among steam-treated samples. Through correlation analysis, pH value was strongly correlated to hemicelluloses and water extractives.     

Optimization and modeling for heat reflux extraction of total yield,stevioside and rebaudioside-A from Stevia rebaudiana (Bertoni) leaves

Stevia rebaudiana (Bertoni) leaves consist of stevioside and rebaudioside-A (Reb-A). This research sought to improve extraction of target steviol glycosides from stevia leaf powder using response surface methodology (RSM) and artificial neural networking (ANN) under these independent variables: ethanol concentration, X₁ (0–100%), extraction temperature, X₂ (55–75°C), and extraction time, X₃ (45–75 min). ANN outperformed as potential alternative to RSM in predicting optimum conditions. Maximum responses were obtained at 100% X₁, 55°C X₂, and 60 min X₃. Heat reflux extraction proved superior to maceration extraction in terms of higher extraction yields with reduced energy consumption and CO₂ emission.     

The Effect of Heat Treatment on Some Mechanical Properties and Color Changes of Uludag Fir Wood

In this study, the effects of heat treatment on color, mass loss, compression strength, and hardness of Uludag fir (Abies bornmulleriana Mattf.) were investigated. Wood specimens conditioned at a relative humidity of 65% and a temperature of 20°C were subjected to heat treatment at 170, 190, and 210°C for 4, 8, and 12 h. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. Color changes were determined according to DIN5033. The results showed that compression strength and hardness of Uludag fir wood decreased to varying extents in relation to intensity of treatment, whereas mass loss increased. We determined that treatment temperature had a more significant effect on color changes than did treatment time. The color of the wood became darker at the higher treatment temperatures.     

Effect of structural change of pitch on the thermal conductivity of epoxy‐based composites filled with heat‐treated pitch

Petroleum‐based pitches were used as filler materials to study the effects of heat‐treatment‐induced changes in pitch structure on the thermal conductivity of epoxy‐based composites. The heat treatment was performed in two steps: the first involved heating the pitch to 250 °C in order to remove the low‐molecular‐weight compounds from the pitch, and the second involved heating the pitch to either 430 or 450 °C. There was no significant difference in the curing behavior of the diglycidyl ether of bisphenol A (DGEBA)/pitch composites, regardless of the heat‐treatment temperature. However, the thermal conductivity of the DGEBA/pitch composites improved with increasing heat‐treatment temperature, and the epoxy composite prepared with pitch heat‐treated at 430 °C exhibited the maximum thermal conductivity. This can be attributed to structural changes in the pitch, such as the distance between adjacent planes (d‐spacing), crystallite height (L_c) and crystallite width (L_a). Although L_c of the pitch increased with increasing heat‐treatment temperature, the d‐spacings and L_a decreased. These results suggest that the heat treatment of the pitch led to a well‐stacked crystalline structure. However, compared with the pitch heat‐treated at 430 °C, that heat‐treated at 450 °C exhibited lower thermal conductivity in the DGEBA/pitch composite because of the low L_a, resulting in the loss of basal carbon as a consequence of in situ gasification, and pyrolysis of the low‐molecular‐weight compounds in the pitch. © 2013 Society of Chemical Industry     

Aging of HTPB/Al/AP Rocket Propellant Formulations Investigated by DMA Measurements

Three HTPB‐based rocket propellant formulations containing ammonium perchlorate and aluminum particles, with different aluminum content and particle size, have been manufactured. The study has focused on the change of mechanical properties with aging time by using dynamic mechanical analysis (DMA). Therefore, propellant formulations underwent an accelerated aging program, in air (RH<10 %), between 60 °C and 90 °C with aging time adjusted to a thermal equivalent load of 15 to 20 years at 25 °C. DMA investigations revealed distinct changes in the shape of the loss factor curve. These curves were modeled with three exponentially modified Gaussian (EMG) functions in order to get the molecular interpretation of the involved aging phenomena by separating the binder fractions with different mobility. Aging of propellant formulations can be followed by considering only two parameters: the areas of the second and third loss factor transition peaks (A₂, A₃), and the corresponding maximum temperature values of the assigned Gauss peaks (Tc₂, Tc₃).     

Inactivation of Aerosolized Viruses in Continuous Air Flow with Axial Heating

Thermal inactivation of viruses has been studied in relevance to food sterilization, water purification, and other “non-aerosol” applications, in which heat treatment is applied for a relatively long time. No data are available on the inactivation of airborne viruses exposed to dry heat for a short time, although this is relevant to bio-defense and indoor air quality control. In this study, we investigated inactivation of aerosolized MS2 viruses in a continuous air flow chamber with axial heating resulted from exposures during ～ 0.1–1 s. For an airborne virion, the characteristic exposure temperature, T _e , was defined utilizing the air temperature profiles in the chamber. The tests were conducted at two air flow rates, Q, which allowed for establishing different thermal flow regimes and exposure time intervals. The experimentally determined inactivation factor, IF, was subjected to correction to account for the temperature profiles. At T _e up to ～ 90°C (Q = 18 L/min) and up to ～ 140°C (Q = 36 L/min), the loss of viral infectivity was relatively modest (≤ 10). However, IF increased exponentially as T _e rose from ～ 90°C to ～ 160°C (for 18 L/min) or from ～ 140°C to ～ 230°C (for 36 L/min). Under specific thermal exposure conditions (～ 170°C and ～ 250°C, respectively), IF exceeded ～ 2.4 × 10⁴ (～ 99.996% infectivity loss)—the maximum quantifiable in this study. The airborne MS2 virions exposed to hot air for < 1 s were found to have survived much higher temperatures than those subjected to thermal treatment in liquid for minutes or hours. The findings are significant for establishing limitations of the heat-based bioaerosol control methods.     

Thermal properties of fats and oils. VIII. Specific heats,heats of fusion,and entropy of alpha and beta tung oils

Summary Beta tung oil belongs to that group of substances which are capable of existing in more than one crystalline form, each of which has a distinet melting point. Three different melting points of the beta tung oil were observed, each dependent upon the rate of cooling. Forms I, II, and III have been used to distinguish beta tung oil melting at 52.8°, 44°, and 28° C., respectively. Equations were developed to express in cals./g./°C. the specific heats of the stable forms of tung oil. Alpha tung oil Solid state (−184° to −43°C.)C _p =0.404+0.001t Liquid state (9° to 80°C.)C _p =0.463+0.0011t Beta tung oil Solid state (−178° to 27°C.)C _p =0.390+0.0013t Liquid state (67° to 87° C.)C _p =0.489+0.00016t The specific heat of beta tung oil was found to be higher when the sample was rapidly cooled than when it was slowly cooled or tempered. The heat of fusion of the beta form of tung oil was caleulated to be 16.12 cals./g., and for the alpha form to be 21.02 cals./g. Entropies at 298.16°K. were 231.04 and 252.15 entropy units for the two forms of these oils, respectively. The liquid glycerides present at any temperature in the melting range were estimated from the data for the heat contents of the oils. The rate of liquidphase formation at constant heat input of both alpha and beta tung oils, unlike that of cottonseed and peanut oils, increased sharply during the final 10° of the interval owing to the greater homogeneity of the glycerides of the former. A report of a study made under the Research and Marketing Act of 1946. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration. U. S. Department of Agriculture.     

Effect of temperature on the release of volatile and odorous compounds in flax fibers

The behavior of flax fibers was investigated at temperatures of 80 °C, 200 °C, 215 °C, and 230 °C for a period of 60 min. First, thermogravimetric and colorimetric analyzes were carried out to characterize the impact of the temperature on the weight loss and the color of the fibers. Then, the release of volatile and odorous compounds from flax fibers was studied using both chemical and sensory approaches. Solid phase micro extraction was done to isolate the volatile organic compounds (VOCs) from the headspace of the sample while gas chromatography‐mass spectrometry (GC‐MS) and olfactometry (O) were used to determine the volatile and odorous compounds released at each temperature. About 24 VOCs were identified in the volatile fraction of flax fibers with a high occurrence of aliphatic aldehydes, phenols, and furans. Quantification by GC‐MS and by the aroma extract dilution analysis method was implemented. The results point to a critical temperature between 215 °C and 230 °C from which the odor of flax fibers becomes more intense, more complex, and with unpleasant features. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43497.     

Artificial Neural Networks Modeling of Ozone Bubble Columns: Mass Transfer Coefficient,Gas Hold-Up,and Bubble Size

This study aims at applying artificial neural network (ANN) modeling approach in designing ozone bubble columns. Three multi-layer perceptron (MLP) ANN models were developed to predict the overall mass transfer coefficient (k_La, s^?1), the gas hold-up (? _G , dimensionless), and the Sauter mean bubble diameter (d_S , m) in different ozone bubble columns using simple inputs such as bubble column's geometry and operating conditions. The obtained results showed excellent prediction of k_La, ? _G , and d_S values as the coefficient of multiple determination (R² ) values for all ANN models exceeded 0.98. The ANN models were then used to determine the local mass transfer coefficient (k_L , m.s^?1). A very good agreement between the modeled and the measured k_L values was observed (R² ?=?0.85).     

A novel method for color determination of edible oils in L*a*b* format

A simple method that uses visible spectrophotometer data and an artificial neural network (ANN) was developed to determine edible oil color based on the L*a*b* format. The 100 oil samples consisted of nine pure oils, a sesame oil blend and three heated oils. Binary, ternary and quaternary mixtures of these 13 oils in different ratios were prepared, and absorbance values of the samples were measured in the visible region (380–700 nm). The absorbance values at wavelengths of 416, 456, 483, 537, 611 and 672 nm were used to train, validate and test the network. Strong correlations between the instrumental L*a*b*ΔE and the estimated L*a*b*ΔE were found for the test samples, with correlation coefficients (R²) of 0.989, 0.984, 0.996 and 0.992 for L*, a*, b*, and ΔE, respectively. The effects of number and combination of the wavelengths used for training of the ANN on the estimation capability of the network for the test samples were also investigated. Although a good agreement, average R² of 0.991– 0 993 for L*a*b*, was obtained for combinations composed of three to six wavelengths with 483 and 537 nm in common, the best R² value was obtained when all six wavelengths were used to train the ANN. The developed method is objective, cost effective and simple, and allows the color measurement with a basic visible spectrophotometer and disposable cuvettes.     

Absorption and migration of bio‐based epoxidized soybean oil and its mixtures with tri(2‐ethylhexyl) trimellitate in poly(vinylchloride)

The efficacy of epoxidized soybean oil (ESO), tri(2‐ethylhexyl) trimellitate, and mixtures thereof as plasticizers for poly(vinylchloride) has been studied. At 80°C, the trimellitate was slower to absorb in this polymer than ESO and was also less soluble, but the former exhibited higher solubility at 120°C. Plasticization efficiencies of stabilized polymeric compositions were similar with ESO and the trimellitate (despite their very different molecular weights). The trimellitate yielded greater mass loss during heat aging of the plasticized compositions, but substituting even minor amounts of it with ESO decreased mass loss synergistically. The trimellitate also resulted in more of an increase in hardness than ESO over time at elevated temperatures, but when aged at 120°C, mixtures of the two surprisingly had more deleterious effects. Thus, although ESO can replace part or all of trimellitates in plasticized PVC, using it as sole plasticizer would be preferable when heat aging performance is a requirement. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41966.     

From Laboratory Experiments to Design of a Conveyor-Belt Dryer via Mathematical Modeling

Abstract

A conveyor-belt dryer for picrite has been modeled mathematically in this work. The necessary parameters for the system of equations were obtained from regression analysis of thin-layer drying data. The convective drying experiments were carried out at temperatures of 40, 60, 80, and 100°C and air velocities of 0.5 and 1.5 m/sec. To analyze the drying behavior, the drying curves were fitted to different semi-theoretical drying kinetics models such as those of Lewis, Page, Henderson and Pabis, Wang and Singh, and the decay models. The decay function (for second order reactions) gives better results and describes the thin layer drying curves quite well. The effective diffusivity was also determined from the integrated Fick's second law equation and correlated with temperature using an Arrhenius-type model. External heat and mass transfer coefficients were refitted to the empirical correlation using dimensionless numbers (J _h , J _D  = m · Re ⁿ ) and their new coefficients were optimized as a function of temperature. The internal mass transfer coefficient was also correlated as a function of moisture content, air temperature, and velocity.     

Hydrogen reduction of chromium chlorides: A kinetic investigation

The reduction of single pellets of chromic and chromous chlorides by hydrogen has been studied kinetically. The reaction 2 CrCL₃ + H₂ →2 HCl + 2 CrCl₂ was investigated over the temperature range 475?615°C. The rate controlling factor in the range of 475?493°C. is vaporization of chromic chloride; the activation energy was found to be 67.8 K.cal./mole. Between S10 and 615°C, the reaction rate is evidently controlled by heat and internal mass transfer processes. In this case the apparent activation energy is 16.6 K.cal./mole. Reduction of chromous chloride, CrCl₂ + H₂ → 2 HCl + Cr, was investigated over the temperature range 675?800°C. This reaction is also controlled by heat and mass transfer and involves vaporization of the chromous chloride. The apparent activation energy is 25.5 K.cal./mole.     

Thermochromic properties of pure NiTiO3 and its Cu- or Co-doped derivatives

Nickel titanate is a yellow-brown pigment which adopts the ilmenite crystal structure as corundum and hematite. Since Cr doped Al₂O₃ and Fe₂O₃ present a thermochromic behavior, NiTiO₃ was also studied for its potential ability to change colour with temperature. Powders were synthesized via a modified Pechini method followed by a calcination step at 700 °C. The thermochromic properties in the 20 °C–400 °C temperature range were collected via the determination of the colorimetric L*a*b* parameters. Namely, the hue continuously shifts from yellow-brown to red-brown, with L*a*b* parameters moving from 60.4/19.2/58.5 to 42.9/30.5/43.1. This colour change is fully reversible even after several cycling. Temperature dependent UV–vis spectroscopy showed that the transparency window at 550–650 nm at room temperature shifts to 575–650 nm at 400 °C. This fully explains the observed colour change. Finally, the effects of Cu or Co doping on NiTiO₃ optical and thermochromic properties were also investigated.     

Oxidation resistance before and after heat treatment for compacted Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–SiC–C mixtures with aluminum-chromium-phosphate binder

Oxidation resistance has been examined for compacted Al₂O₃–SiC–C mixtures, which contain an aluminum-chromium-phosphate binder without firing (DTA method) and ones that have been previously fired and given isothermal heat treatment at 800°C (as indicated by the mass loss). To obtain oxidation-resistant materials, the content of silicon carbide should not exceed 10 wt.% and the recommended graphite content is not more than 20 wt.%. Translated from Novye Ogneupory, No. 2, pp. 38 – 43, February, 2009.