scholarly journals Effect of Ultra-Fine Grinding on the Structure of Plant Raw Materials and the Kinetics of Melanin Extraction

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2236
Author(s):  
Igor Lomovskiy ◽  
Ekaterina Podgorbunskikh ◽  
Oleg Lomovsky
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Extraction Rate ◽  
Key Factors ◽  
Fine Grinding ◽  
Plant Raw Materials ◽  
Ultra Fine Grinding ◽  
Buckwheat Husk ◽  
Kinetics Of ◽  
Degree Of Order

Enhancing the extraction rate is one of the key objectives in optimization of extraction of substances from biogenic raw materials. Ultra-fine grinding of plant raw materials (to achieve particle size less than 300 µm) is a very appealing method for increasing the extraction rate using relatively simple equipment. However, this approach often fails to yield the desired result. This study focuses on the kinetics of melanin extraction from two types of raw materials: fungus Ganoderma applanatum and buckwheat husk. Particle size is shown to be just one of the key factors. The degree of order of plant-based feedstock strongly affects the intraparticle diffusion constants and can be a parameter controlling the diffusion rate. It has been shown that there exist optimal degrees of disorder of the crystal structure of plant raw materials, which have a dome-shaped dependence pattern and allow one to increase the diffusion coefficient by several dozen times. The kinetics of melanin extraction was described by some kinetic models that include the first order equation, the Baker and Lonsdale model, the Axelrud equation, and the Ritger–Peppas model.

scholarly journals Method of obtaining and studying the optical properties of carbon quantum dots.

2019 ◽  
Vol 19 (3) ◽  
pp. 226-229
Author(s):  
S.D. Bardasevska ◽  
I.M. Budzulyak ◽  
S.I. Budzulyak ◽  
B.I. Rachiy ◽  
R.V. Ilnytskyi ◽  
...  
Keyword(s):  
Raw Materials ◽  
Wavelength Region ◽  
Short Wave ◽  
Carbon Quantum Dots ◽  
Long Wavelength ◽  
Plant Raw Materials ◽  
Wave Region ◽  
Exciton Mechanism ◽  
Short Wave Region ◽  
Kinetics Of

The proposed method of synthesis of CQDs on the basis of nanoporous carbon obtained from plant raw materials. It is established that in the short-wave region a band is registered, which is due to the exciton mechanism of recombination, whereas in the long-wavelength region it is related to the state of defects. The kinetics of PL extinction is not strictly exponential, which most likely indicates the distributed nature of fading from individual emitters.

Analytical Light Microscopy: Examples of Practical Problemsolving and Efficiency in Pharmaceutical Quality Control and Formulation

1998 ◽  
Vol 4 (S2) ◽  
pp. 474-475
Author(s):  
D. A. Stoney ◽  
W. C. McCrone
Keyword(s):  
Particle Size ◽  
Quality Control ◽  
Light Microscopy ◽  
Raw Materials ◽  
Pharmaceutical Products ◽  
Macroscopic Description ◽  
Considerable Effort ◽  
Case Examples ◽  
Kinetics Of ◽  
Dissolution And Precipitation

Five applications of analytical light microscopy to problem-solving in the pharmaceutical industry are described and illustrated by case examples. Problems included are (1) the caking of pharmaceutical products, (2) chemical incompatibility, (3) nucleation and precipitation, (4) recognition of hydrates and polymorphs, and (5) identification and sourcing of contaminant particles.Considerable effort goes into the sizing of solid pharmaceutical raw materials and products. In many instances, particle size is used to help control the rate and uniformity of dissolution, which in turn affects the kinetics of drug delivery. Caking is a macroscopic description of the change in a sample from a finely-divided powder to a single solid molded aggregate. Caking obviously has a severe impact on handling and dissolution characteristics.Caking of a powder is almost always caused by moisture through the cyclical dissolution and precipitation on the surfaces of the particles. When exposed to sufficient vapor pressure, often through changes in humidity or temperature,

scholarly journals Analysis of a grinding efficiency in the electromagnetic mill for variable process and feed parameters

2017 ◽  
Vol 18 ◽  
pp. 01012
Author(s):  
Marta Wołosiewicz-Głąb ◽  
Dariusz Foszcz ◽  
Daniel Saramak ◽  
Tomasz Gawenda ◽  
Damian Krawczykowski
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Raw Material ◽  
Grinding Process ◽  
Key Factors ◽  
Copper Ore ◽  
Factors Affecting ◽  
Grinding Media ◽  
Grinding Efficiency ◽  
The Impact

Article describes issues related to the assessment of raw materials grinding efficiency in an electromagnetic mill. Application of such type of mill in grinding processes can result in measurable benefits of more efficient raw material grinding by reducing time needed to produce a product of a suitable particle size compared to conventional mills. The expected effect of application of a system based on an electromagnetic mill is to achieve a lower energy consumption of grinding process for raw material processing compared to the existing equipment used for the fine grinding. A key element of correct design of comminution circuits in processing of particular feed mineral is to identify the impact of key factors affecting the efficiency of the grinding process. The most important factors determining the efficiency of the grinding process are the time, the construction parameters of the machine, the type of grinding media used in grinding process, as well as the parameters of the feed, among others the crushing resistance or particle size. The paper presents the results of kinetic study of copper ore grinding in electromagnetic mill for variable feed particle size distribution of and different sizes of grinding media.

Study on Ultra-Fine Grinding and In Situ Modification of Taixi Super-Low-Ash Anthracite

2011 ◽  
Vol 402 ◽  
pp. 556-559 ◽  
Author(s):  
An Ning Zhou ◽  
Yan Wu ◽  
Fu Sheng Yang
Keyword(s):  
Particle Size ◽  
Fourier Transformation ◽  
Fine Grinding ◽  
In Situ Modification ◽  
Particle Size Analyzer ◽  
Ultrafine Grinding ◽  
Coal Powder ◽  
Ultra Fine Grinding ◽  
Grinding Time

Abstract. This paper discussed the ultra-fine grinding and in-situ modification of Taixi super-low-ash anthracite in stirred mill. Particle size distribution of the products was determined by laser particle size analyzer. The surface morphology and dispersion of the powder were detected by scanning electron microscopy (SEM), and surface structure of the modified powder was measured by Fourier transformation infrared (FTIR). It was found that the optimum ultrafine grinding time is 70 min in the stirred mill, the suitable maleic anhydride (MAH) dosage was 1 wt% of the ground coal powder, MAH can play roles in grinding aid and modifier. On these conditions, both the grinding and dispersion effect are the best.

scholarly journals STUDY OF COMPARATIVE EXTRACTABILITY OF BIOLOGICALLY ACTIVE SUBSTANCES FROM ST. JOHN’S WORT HERB OF VARIOUS SERIES

2021 ◽  
Vol 9 (1) ◽  
pp. 11-16
Author(s):  
R.M. Streltsova ◽  
◽  
А.B. Denisova ◽  
Z.F. Gromova ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Extract ◽  
Raw Materials ◽  
Wave Length ◽  
Biologically Active ◽  
High Yield ◽  
Aqueous Extracts ◽  
Solid Residue ◽  
Plant Raw Materials ◽  
Related Substances

Aim. To study extractability of a complex of active and related substances and flavonoids from St. Johns Wort herb of various series and anufacturers and identification of factors affecting the quality of aqueous extracts from St. Johns Wort herb. Materials and Methods. The object of study was St. Johns Wort herb of four series of two manufacturers, and aqueous extracts obtained from these series of St. Johns Wort herb. Aqueous extracts were made in the infusion mode in accordance with the requirements of the Order of the Ministry of Health of the Russian Federation №751n of October 26, 2015. The ratio of raw materials and extractive solvent was 8:100. The obtained aqueous extracts were evaluated by color and smell parameters. A complex of biologically active and related substances extracted from St. Johns Wort herb was evaluated by the solid residue index. Quantitative determination of flavonoids in recalculation for rutin was performed by spectrophotometric method on Bio-RADSmartSpecPlus spectrophotometer at 410 nm wave length. Results. Raw materials of different series differ in external characteristics and fineness. Raw materials of 221218 series contain 17.46% of particles larger than 3 mm, and raw materials of 20218 series – 4.92%. Raw materials of 221218 series include more particles of the coarse parts of the plant. Raw materials of 10119 series have a more uniform distribution of particles by fractions, but a rather large number of small particles. The maximal solid residue was obtained from raw materials of 20218 series – 1.7716%, the minimal – from raw materials of 221218 series – 0.6183%. The maximal flavonoid content was found in aqueous extract obtained from raw materials of 20218 series – 1.988%, the minimal content – from raw materials of 221218 series – 0.6183%. A sufficiently high yield of flavonoids in the aqueous extract was established for raw materials of 10119 series – 1.9711%. Conclusions. It was found that raw materials containing more soft parts of plants and characterized by the presence of a higher percent of fine fractions of particles, have the best extractability. At present, in the SP (Russia) of the 14th edition, only fractions of St. Johns Wort herb with a particle size of more than 7 mm and less than 0.18 mm are normalized. In our opinion, it is reasonable to include requirements to particle size and their content for the main fractions of the feedstock.

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