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Evaluation of rice straw for purification of lovastatin, TAPPI Journal November 2021
ABSTRACT: Cholesterol synthesis in the human body can be catalyzed by the coenzyme HMG-CoA reductase, and lovastatin, a key enzyme inhibitor, can reduce hypercholesterolemia. Lovastatin can be obtained as a secondary metabolite of Aspergillus terreus ATCC 20542. In this study, rice straw of lignocellulose was used in aeration and agitation bath fermentation in a 1-L flask, and a maximal crude extraction rate of 473 mg/L lovastatin was obtained. The crude extract was treated with silica gel (230–400 mesh) column chromatography. Ethyl acetate/ethanol (95%) was used as the mobile phase, and isolation was performed through elution with various ethyl acetate/ethanol ratios. The highest production rate of 153 mg/L was achieved with ethyl acetate/ethanol in a ratio of 8:2. The lovastatin gained from the crude extract was added to 12 fractions treated with 0.001 N alkali, and acetone was then added. After 24 h of recrystallization at 4°C, the extract underwent high-performance liquid chromatography. The purity had increased from 25% to 84.6%, and the recovery rate was 65.2%.
Journal articles
Magazine articles
Rheological behavior of magnetic pulp fiber suspensions, TAPPI Journal June 2021
ABSTRACT: This paper is focused on the rheology of magnetic pulp suspensions in absence and presence of an external magnetic field. Magnetic fibers were prepared by the lumen loading method using bleached eucalyptus fibers and cobalt ferrite (CoFe2O4) nanoparticles. The effect of mass consistency, temperature, concentration of magnetic fibers, and magnetic field strength on yield stress and apparent viscosity of the suspensions were investigated. In the absence of an applied field, a dependence of yield stress with consistency, as well as with the percentage of magnetic fibers present in the suspension, was found. In flow tests, all the suspensions exhibited shear-thinning behavior, showing that the viscosity is only affected by the consistency of the suspension. On the other hand, magnetorheological measurements show a negative effect of the applied magnetic field on the viscosity of the suspension.
Journal articles
Magazine articles
Effects of different ammonium lignosulfonate contents on the crystallization, rheological behaviors, and thermal and mechanical properties of ethylene propylene diene monomer/polypropylene/ammonium lignosulfonate composites, TAPPI Journal January 2020
ABSTRACT: Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has an excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the AL contents on the crystallization behaviors, rheological properties, thermal properties, and mechanical properties of the composites. The results showed that the AL content had a noticeable impact on the performance of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.
Journal articles
Magazine articles
Root cause analysis of cationic polymer additive efficiency decline in virgin and recycle containerboard mills, TAPPI Journal January 2020
ABSTRACT: It is well known that retention, drainage and strength polymers struggle to perform (if at all) in virgin containerboard mills. In-depth studies have been undertaken in this area for more than seven years, investigating the issue from all directions. A key finding of this work is that soluble lignin is detrimental to chemical efficiency. A strong correlation exists between decreased chemical efficiency and high soluble lignin. Both recycled systems and virgin systems have been studied, and this correlation holds true regardless of furnish. The primary area of concern is virgin container-board, because these mills tend to have the highest lignin levels. Some highly closed recycled mills can also build elevated lignin levels that can negatively affect chemical efficiency.
Journal articles
Magazine articles
Understanding conductivity and soda loss
Understanding conductivity and soda loss
Journal articles
Bleaching optimization at WestRock mill in Covington, Virgi
Bleaching optimization at WestRock mill in Covington, Virginia, TAPPI JOURNAL September 2016
Journal articles
Using white liquor as the alkali source in oxygen delignific
Using white liquor as the alkali source in oxygen delignification, TAPPI JOURNAL September 2016
Journal articles
Image classification of the furnace bed height in recovery boilers, TAPPI Journal July 2026
ABSTRACT: The goal of this study is to develop an approach for classifying char bed height in a recovery boiler during operation. The resulting classified images form a dataset that can be used by the mill to support operational improvements. The study integrates data from the digester, evaporation plant, recovery boiler, and recausticizing plant, along with the classified image data. A convolutional neural network (CNN) was trained on bed camera images that were manually annotated to classify furnace bed height. The model was then used to generate a binary bedheight parameter over a 16-month period, and an extreme gradient boosting (XGBoost) model was applied to identify relationships with operating parameters across the recovery cycle. The outcomes of this research may offer deeper insights into the processes underlying bed dynamics. Ultimately, the developed system may serve as a tool for optimizing bed conditions and supporting stable combustion.
Journal articles
Editorial: Honoring the contributions of Dr. Mahendra Doshi
n this column, we would like to recognize the contributions to TAPPI and TAPPI Journal made by Dr. Mahendra Doshi, who passed away in April. A long-time member of TAPPI and a TAPPI Journal Editorial Board Member for many years, he is recognized for his research in screening system analysis, wax, and stickies removal in the field of recycling. Doshi was a pioneer in stickies classification and measurement methods for macro and micro stickies. During his career, he consulted with paper mills all over the world, providing mills with solutions for deinking, wax, stickies, yield, dirt count, and brightness.
Journal articles
Functional surfaces produced by foam coating, TAPPI JOURNAL
Functional surfaces produced by foam coating, TAPPI JOURNAL August 2016