Use of Superheated Steam Drying to Increase Strength and Bulk of Papers Produced from Diverse Commercial Furnishes

Studies from this laboratory have documented significant changes in properties when paper is dried in superheated steam rather than, as in all current processes, in air. Extending these investigations to additional important pulp types, to recycled pulps and to filled papers, using commercial furnishes from mills, has identified further grades of paper for which drying in superheated steam enhances key properties. For bleached chemithermomechanical pulps and blends with kraft pulp as used for tissue and toweling, strong paper resulted, with 10% higher bulk. Linerboard from 100% recycled old corrugated containers (OCC) is obtained with various strength properties increased by up to 21% with no densification, actually a 4% increase in bulk. Linerboard from high-yield (55-67%) virgin kraft pulps show 23 to 37% increase in strength and toughness. Filled papers containing 0-10% clay can be produced with the same brightness but about 23% higher tensile index when dried in superheated steam.     

Use of Superheated Steam Drying to Increase Strength and Bulk of Papers Produced from Diverse Commercial Furnishes

ABSTRACT

Studies from this laboratory have documented significant changes in properties when paper is dried in superheated steam rather than, as in all current processes, in air. Extending these investigations to additional important pulp types, to recycled pulps and to filled papers, using commercial furnishes from mills, has identified further grades of paper for which drying in superheated steam enhances key properties. For bleached chemithermomechanical pulps and blends with kraft pulp as used for tissue and toweling, strong paper resulted, with 10% higher bulk. Linerboard from 100% recycled old corrugated containers (OCC) is obtained with various strength properties increased by up to 21% with no densification, actually a 4% increase in bulk. Linerboard from high-yield (55–67%) virgin kraft pulps show 23 to 37% increase in strength and toughness. Filled papers containing 0–10% clay can be produced with the same brightness but about 23% higher tensile index when dried in superheated steam.     

Optimization of Microwave-Assisted Extraction of Astaxanthin from Haematococcus Pluvialis by Response Surface Methodology and Antioxidant Activities of the Extracts

Abstract

Microwave-assisted extraction (MAE) was applied for the extraction of astaxanthin from Haematococcus pluvialis and response surface methodology (RSM) was used to optimize extraction parameters to the content of astaxanthin. Four independent variables such as microwave power (W), extraction time (sec), solvent volume (mL), and the number of extraction were optimized in this paper. The optimal conditions were determined and tri-dimensional response surfaces were plotted from the mathematical models. The F-test and p-value indicated that microwave power, extraction time, the number of extraction, and their quadratic had a highly significant effect on the response value (p <0.01), then the solvent volume and the interaction effects of microwave power and the number of extraction also displayed significant effect (p <0.05). Considering the extraction efficiency, the optimized conditions of MAE were as follows: microwave power was 141 W, extraction time 83 sec, solvent volume 9.8 mL, the number of extraction four times. About 594 ± 3.02 µg astaxanthin was extracted from Haematococcus pluvialis the dried powders (100 mg) under the optimal conditions, and it close to the predicted contents (592 µg). The antioxidant activities of the extracts obtained under optimal conditions were analyzed, and the results showed that the extracts presented strong ability of inhibiting the peroxidantion of linoleic acid, exhibited strong radical-scavenging properties against the DPPH, as well as strong reducing power.     

响应面优化法在PDMS/PVDF膜制膜条件优化中的应用

用响应面优化法优化了乙烯基封端PDMS/PVDF渗透汽化透醇膜的制膜条件,研究了硅橡胶浓度、B/A质量比、交联温度和交联时间对膜性能的影响,拟合了分离因子、渗透通量与四因素之间的回归方程,并用方差分析法考察了四因素的主效应、二次效应以及相互作用效应对复合膜的分离因子与渗透通量的影响。研究发现,硅橡胶浓度对膜的分离因子与渗透通量的影响最为显著,交联时间对分离因子几乎没有影响。通过对回归方程的优化分析得知,在料液乙醇浓度为10%(wt),操作温度40℃条件下,当硅橡胶浓度为93%(wt),B/A质量比为0.08,交联温度为100℃,交联时间为13.83 h时,膜的综合分离性能达到最佳,此时分离因子与渗透通量预测值分别为9.47、77.57 g(m2 h)1,渗透侧乙醇浓度达到51.3%(wt)。回归方程的验证实验结果表明,回归方程的估计值与实验值较为吻合,可用于乙烯基封端的PDMS/PVDF复合膜的渗透汽化性能的预测与优化。     

Hybrid Drying of Rubberwood Using Superheated Steam and Hot Air in a Pilot-Scale

A pilot-scale rubberwood dryer was constructed and injected with superheated steam and hot air to study the effect of the hybrid system on the drying rate and mechanical properties of the wood. A total of 300 pieces of rubberwood boards, each with dimensions of 1000 mm long × 76.2 mm wide × 25.4 mm thick, were stacked in 1.0 m × 1.0 m × 1.7 m (1.7 m³) pallet. The stack was impinged with alternating cycles of superheated steam and hot air. The time required for conventional drying was 168 hours, but the drying time for the hybrid system was only 64 hours, resulting in a 62% reduction.

After being dried, the rubberwood boards were mechanically tested for static bending, compression strength, hardness, and shear strengths. From the mechanical tests, the hybrid drying system using superheated steam and hot air had no significant effect on the mean shear strength parallel-to-grain; however; the mean compression strength parallel-to-grain was reduced by 24.2% and the mean MOR by 21.4%. Nonetheless, the mean MOE was increased by 30.4% and the mean of hardness by 16.4%.     

响应面法优化东京野茉莉油制备生物柴油的工艺研究

研究了响应面法优化东京野茉莉油制备生物柴油的工艺。通过单因素实验,对影响转化率的四个主要因素:油醇摩尔比、催化剂用量、反应时间、反应温度进行考察,并根据Box-Behnken中心组合进行4因素3水平的实验设计,以东京野茉莉生物柴油转化率为响应值,进行响应面分析(RSA)。结果表明,东京野茉莉生物柴油的最佳工艺条件为:油醇摩尔比1∶8、催化剂用量为油质量的0.78%、反应时间2.2 h、反应温度60℃,理论转化率为95.81%。实际验证值为95.32%,理论值与实际值相对误差为0.49%,说明通过响应面法能得到一个预测试验结果的模型方程。以东京野茉莉油为原料通过酯化反应制取的生物柴油与0#柴油及国标GB/T 20828-2007主要性能相似,通过与石油柴油调和或添加降凝剂等方法,可改善低温流动性。     

蒸汽爆破提取银杏叶黄酮类化合物的工艺研究

采用新近发展的蒸汽爆破技术对银杏叶进行预处理提取黄酮类物质,通过单因素实验,采用响应面法进行处理过程中的多因素组合的工艺优化,研究汽爆压力、汽爆时间、固液比对黄酮提取效率的影响,建立并分析了各因素与处理后黄酮提取率的数学模型。得到的优化条件为:汽爆压力0.38 MPa,汽爆时间235 s,固液比1∶15。与传统有机溶剂提取法相比,蒸汽爆破预处理使提取率提高了2.1倍。     

Application of Response Surface Methodology to Optimize Three Phase Partitioning for Purification of Laccase from Pleurotus ostreatus

We used a novel approach to purify Pleurotus ostreatus laccase using the three phase partitioning (TPP) methodology. The aim of our research was to study the effect of TPP parameters on laccase purity and yield. The response surface methodology (RSM) has been applied to design the experiments to evaluate the interactive effects of the three most important operating variables: ammonium sulphate saturation (w/v) (20–80%), ratio of crude extract to t-butanol (v/v) (1:1 to 1:3), and temperature (20–60°C). Using this methodology, the optimum values for the critical components were obtained as follows: ammonium sulphate saturation (w/v), 50–60%; ratio of crude extract to t-butanol (v/v) 1.0:1.8; temperature 42–45°C, respectively. Under optimal conditions, the experimental laccase yield and purity was 184% and 7.22-fold, respectively. SDS-PAGE and RP-HPLC revealed that the laccase was purified by TPP. The determination coefficients (R²) were 0.9891 and 0.9728 for laccase purity and yield, respectively, indicating an adequate degree of reliability in the model. To our knowledge, the present work demonstrates for the first time the successful application of RSM to TPP.     

Dielectric Properties and Optimization of Parameters for Microwave Drying of Petroleum Coke Using Response Surface Methodology

The dielectric properties of petroleum coke at five temperatures between 20 to 100 ^° C, covering different moisture content levels at 2.45 GHz, were measured using an open-ended coaxial probe dielectric measurement system. The effects of drying temperature, duration of drying, and sample mass on the moisture content and dehydration rate of petroleum coke was assessed utilizing the response surface methodology. The dielectric constant, loss factor, and loss tangent were all found to increase nearly linearly with increase in moisture content. Three predictive empirical models were developed to relate the dielectric constant, loss factor, and loss tangent of petroleum coke as a linear function of moisture content from 3–10%. An increase in temperature between 20 to 100 ^° C was found to increase the dielectric properties. The penetration depth was observed to increase linearly with decrease in moisture content in the range of 3 to 10%. A predictive empirical model was developed to calculate penetration depth for petroleum coke. Two mathematical models were established and analyzed using RSM to describe the relationship between the microwave drying conditions and the responses, moisture content, and dehydration rate. Statistical analysis with response surface regression showed that microwave drying temperature, duration of drying, and sample mass were significantly related to moisture content and dehydration rate. Based on the RSM analysis, the optimum process conditions were estimated to be a microwave drying temperature of 75 ^° C, drying duration of 10 sec, and sample mass of 60 g, with the resultant moisture content being 0.34 at a dehydration rate of 2.94 g/min.     

响应面法优化甘蔗糖蜜酸催化水解制备乙酰丙酸

在甘蔗糖蜜酸催化水解制备乙酰丙酸的过程中,以乙酰丙酸（levulinic acid, LA）产率为考察对象,在单因素实验基础上,考察了反应时间、糖蜜浓度、催化剂浓度比、反应温度的作用。采用Box-Benhnken中心组合试验原理和响应面分析法（RSM）对乙酰丙酸制备条件进行优化。结果表明,建立的二次多项式模型回归性显著而失拟项不显著,模型拟合性良好。各因素对LA产率有显著性影响,依次为：催化剂浓度比>反应温度>反应时间>糖蜜浓度。实验最终确定乙酰丙酸最佳制备条件为：反应时间5 h、糖蜜浓度40 wt%、催化剂浓度比23.40:1、反应温度151℃。该条件下进行三次重复试验,乙酰丙酸的实际平均产率为30.11 wt%,与预测值30.96 wt%相对偏差0.85 wt%,模拟可靠。     

Modelling of Fish Drying Kinetics Using a Combination of Surface Response Methodology and Diffusional Models

ABSTRACT

Drying is a common fish preservation technique used in developing countries. Analysis of process factors involved in controlled fish drying permits process optimization and assists in design of suitable dryers. Various methodologies, with models of different complexities (analytical, semi–empirical and empirical models), have been used to investigate fish drying kinetics. The original feature of this study is the combined use of surface response methodology and diffusional models. In a limited number of experimetns, this combination allowed development of a predictive tool for assessing fish drying mechanisms and drying time.     

响应面法优化氟硅酸铵制备白炭黑和氟化铵

本文以氟硅酸铵和碳酸氢铵为原料制备白炭黑和氟化铵(NH₄F)。根据单因素实验并结合Box-Behnken响应面法建立二次回归模型进行方差分析和验证,考察了液固比、配料比、反应温度、反应时间四个因素对白炭黑收率和NH₄F浓度的影响,通过响应面法优化得到较优工艺条件:液固比8,配料比5.49,反应温度76.5 ℃,反应时间49.08 min。在该工艺条件下进行验证实验得到白炭黑收率为96.90%,NH₄F浓度为2.02 mol/L,预测值与实验值无显著差异,验证了二次回归模型的可靠性。对产品白炭黑进行XRD、IR、TG-DSC、SEM、BET表征,及粒度分析和性能测试,对于产品NH₄F,采用氟离子选择性电极法测定其浓度,并对其性能进行检测。证实了白炭黑产品粒度为微米级,且是一种比表面积达316.83 m²/g的介孔材料,其中SiO₂的质量分数高达97.77%,外观、加热减量、灼烧减量、pH值、重金属含量和吸油值均达到行业标准。NH₄F产品中氟化铵含量、游离酸含量和氟硅酸盐含量均达到国家标准。     

Mixing of Oil in Water Through Electrical Resistance Tomography and Response Surface Methodology

The mixing performance of the oil‐in‐water dispersion system was evaluated. Using an electrical resistance tomography system composed of two measuring planes, the effect of parameters such as impeller type, impeller speed, oil type, and oil volume fraction on the mixing performance through axial mixing indices were explored. The oil type and the oil volume fraction were identified as the most influential factors on the mixing index. Castor oil, with the highest viscosity of the tested oils, was found as the most difficult oil to disperse. The Scaba impeller was the most efficient impeller in dispersing oil in water. The interactions between oil type and impeller type as well as between impeller speed and oil type, had the greatest impact on the mixing index.     

Optimization of Lipase-Catalyzed Interesterification of Flaxseed Oil and Tricaprylin Using Response Surface Methodology

The biosynthesis of structured lipids (SL) in organic solvent media was carried out by the interesterification of flaxseed oil (FO) and tricaprylin (TC), using Novozym 435. The bioconversion yield (BY, %) of medium-long-medium type SL, including C-caprylic and Ln-linolenic acids (CLnC), La-linoleic acid (CLaC) and O-oleic acid (COC), was monitored. Response surface methodology was used to obtain significant models for the responses, on the basis of a five level, five variable central composite rotatable design. In the experimental preliminary trials significant reaction parameters, including reaction temperature (T _r), TC/FO molar ratio (M _r), enzyme concentration (E _c), reaction time (R _t) and initial water activity (a _w), were considered for optimization. Significant models for CLnC, CLaC and COC were determined after regression analysis with backward elimination. The optimal conditions, generated for a maximum CLnC, CLaC and COC, were found to be 54.50–56.25 °C for T _r, 6.23–6.25 mol/mol for M _r, 2.68–3.13 % for E _c, 36.58–37.50 h for R _t and 0.15–0.33 for a _w. Under these optimum conditions, the BY of CLnC, CLaC and COC was predicted to be 32.48–36.67, 3.26–3.38 and 5.79–6.16 %, respectively.     

响应面法优化海藻酸盐复合凝胶微球的制备工艺条件

以氯化钙(CaCl2)和壳聚糖(CS)作为交联体系,膨润土(BT)作为吸附剂制备了负载甲氨基阿维菌素苯甲酸盐的海藻酸盐(SA)复合凝胶微球,以其载药率(DLR)和平衡溶胀率(ESR)的比值作为响应值(UR,UR=DLR/ESR),采用Box-Behnken设计建立模型和考察海藻酸钠质量分数(1.00~3.00 wt.%)、膨润土质量分数(1.00~5.00 wt.%)、氯化钙浓度(0.10~0.40 mol/L)和壳聚糖质量分数(0.50 ~1.50 wt.%)对响应值的影响。结果表明响应值与四因素关系符合二次模型,在实验范围内,该数学回归模型具有良好的预测性。在各因素设定范围内预测最佳工艺条件为：海藻酸钠浓度2.39 wt.%、膨润土浓度2.81 wt.%、氯化钙浓度0.24 mol/L、壳聚糖浓度0.71 wt.%。在该条件下进行3次重复实验,实际测得的平均响应值为3.5509%,与理论预测值3.5836%无显著性差异。在该条件下制备的复合凝胶微球,包封率为98.31%,载药率为2.11%,并且具有良好的缓释性能。     

Modeling of Alkali Pretreatment of Rice Husk Using Response Surface Methodology and Artificial Neural Network

Rice husk as a widely available lignocellulosic material was subjected to an alkaline pretreatment process. The alkaline pretreatment was carried out under various conditions. The influence of process parameters, such as pretreatment time, solid loading, and NaOH concentration, on the glucose and xylose yields were investigated by means of appropriate models. The maximum glucose and xylose yields obtained under optimum pretreatment condition were 68.82% and 53.77%, respectively. Response surface methodology (RSM) and artificial neural network were used to model the pretreatment processes. Both modeling methodologies were statistically compared by means of the coefficient of determination and relative mean square error. It was concluded that the artificial neural network shows a somewhat better performance compared to RSM.     

Response Surface Methodology and Artificial Neural Networks for Optimization of Catalytic Esterification of Lactic Acid

Response surface methodology (RSM) and artificial neural network (ANN) models were employed to study the esterification of lactic acid and isoamyl alcohol. A carbon-based solid acid catalyst prepared by wet impregnation was used in the esterification reaction. Experimental characterization revealed its potential to serve as catalyst for the esterification reaction. The experiments were performed based on the design of experiments provided by RSM and ANN models. Both models were compared on the basis of prediction efficacies and deviation from actual data. The prediction data results demonstrated that the ANN model gave better prediction efficiency and lower prediction deviation than the RSM model. The ANN model provided a higher coefficient of determination and lower error values than the RSM model. Moreover, the catalyst exhibited a good stability and recyclability up to four reaction cycles.     

Functional Ionic Liquids Catalyzed the Esterification of Ricinoleic Acid with Methanol to Prepare Biodiesel: Optimization by Response Surface Methodology

An efficient route to preparing biodiesel by the esterification of ricinoleic acid (RA) with methanol was investigated in the work. Six kinds of functional ionic liquids (IL) were selected as catalysts. The effects of reaction variables (reaction time, temperature, IL load, and the ratio of reaction substrates) were also evaluated and optimized using response surface methodology (RSM). Among IL tested, 1‐butylsulfonic‐3‐methylimidazolium trifluoromethanesulfonate showed the highest catalytic efficiency for the esterification. Reaction variables were optimized using RSM as follows: IL load 4 % (relative to the weight of RA), molar ratio of methanol to RA 9.2:1, 67 °C, and 28 min. Under the optimized conditions, the esterification degree of RA was 92.3 ± 1.7 %.     

Application of Response Surface Methodology for Optimization of Water Treatment by Fe3O4/SiO2/TiO2 Core-Shell Nano-Photocatalyst

In the present work, Fe₃O₄/SiO₂/TiO₂ nano-photocatalyst with a core-shell structure was successfully used for the removal of Methylene Blue (MB) as a model organic pollutant from water. The resultant nanoparticles were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, Brunauer–Emmett–Teller method, and Barrett–Joyner–Halenda method. Response surface methodology (Box–Behnken approach) was applied to optimize the removal of MB from water. This optimization was used to evaluate the effect of experimental variables and their interaction in achieving the optimum conditions in removal of MB from water which was measured via UV-visible spectroscopy. The optimum conditions were found to be at Si/Fe₃O₄ wt% = 17.35%, Ti/Fe₃O₄ wt% = 50.17%, and calcination temperature = 392°C with a 91.1% removal efficiency. Finally, a model was established and the predicted results from the model fitted well with the experimental values indicating that the optimization was successful.     

Optimization of Cellulase Production from Isolated Cellulolytic Bacterium: Comparison between Genetic Algorithms,Simulated Annealing,and Response Surface Methodology

The present study discusses optimization of cellulase production from isolated cellulolytic bacterium. A simulated annealing (SA) algorithm is proposed for optimization of these processes to achieve the desired production goal. The approach was compared to the use of evolutionary algorithms, i.e., genetic algorithms (GAs) and response surface methodology (RSM). Ochrobactrum haematophilum was identified as the isolated bacteria. Carboxymethyl cellulose (CMC) concentration, yeast extract, pH, and incubation temperature were the significant factors screened by Plackett–Burman design and further optimized using a central composite design. The optimum values obtained were CMC concentration = 4.76% (w/v), yeast extract = 2.03% (w/v), pH = 6.3, and temperature = 44.2°C. Carboxy methyl cellulase (CMCase) activity at these values was experimentally determined to be 3.55 ± 0.16 U/ml, which was 2.8 times than the unoptimized system (1.23 U/ml). The growth-associated and non-growth-associated Leudeking–Piret constants, α and β, were respectively determined to be 0.3943 and 0.0105. The Michaelis–Menten constants, V_max and K_m, were determined to be 0.67 µmol/min and 2.42 mg CMC/ml, respectively. The variable-sized SA seems to be the best alternative, outperforming the GAs, showing a fast convergence and low variability among the several runs for optimized production cellulose recovery. The SA models are found to be capable of better predictions of cellulase production. The results of the SA-based RSM model indicate that it is much more robust and accurate in estimating the values of dependent variables when compared with the GA-based RSM models and only RSM models.