scholarly journals RESEARCH OF THE COMPOSITION OF PRODUCTS OF MICROWAVE PYROLYSIS OF WOOD

2021 ◽  
pp. 32-36
Author(s):  
O. I. Tuzhikov ◽  
T. V. Khokhlova ◽  
S. A. Orlova ◽  
O. O. Tuzhikov
Keyword(s):  
Molecular Weight ◽  
Spectroscopic Analysis ◽  
Liquid Fraction ◽  
Raw Material ◽  
Gas Mixture ◽  
Low Molecular Weight ◽  
Pyrolysis Process ◽  
Microwave Pyrolysis ◽  
Microwave Action ◽  
Composition Of Products

A method of microwave action on wood of various species was developed, as a result of which the pyrolysis process was carried out. Allocated solid, gaseous fractions, as well as as a result of condensation of a vapor-gas mixture, pyrolysate, which is a raw material for the production of low molecular weight organic compounds of various classes. Gas chromatography-mass spectroscopic analysis of the liquid fraction was carried out, the components included in its composition were identified. The proposed method allows liquefaction of wood for 20-30 minutes in the temperature range from 230 to 423 °С.

scholarly journals Extraction and Hypolipidemic Activity of Low Molecular Weight Polysaccharides Isolated from Rosa Laevigata Fruits

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Xuejiao Zhang ◽  
Yihong Hu ◽  
Chenzhong Jin ◽  
Weiguo Wu
Keyword(s):  
Oxidative Stress ◽  
Molecular Weight ◽  
Stress Responses ◽  
High Fat Diet ◽  
Raw Material ◽  
Low Molecular Weight ◽  
Peroxisome Proliferator ◽  
Extraction Temperature ◽  
High Fat ◽  
Chinese Medicinal Herb

Three novel low molecular weight polysaccharides (RLP-1a, RLP-2a, and RLP-3a) with 9004, 8761, and 7571 Da were first obtained by purifying the crude polysaccharides from the fruits of a traditional Chinese medicinal herb Rosae Laevigatae. The conditions for polysaccharides from the R. Laevigatae fruit (RLP) extraction were optimized by the response surface methodology, and the optimal conditions were as follows: extraction temperature, 93°C; extraction time, 2.8 h; water to raw material ratio, 22; extraction frequency, 3. Structural characterization showed that RLP-1a consisted of rhamnose, arabinose, xylose, glucose, and galactose with the ratio of 3.14 : 8.21 : 1 : 1.37 : 4.90, whereas RLP-2a was composed of rhamnose, mannose, glucose, and galactose with the ratio of 1.70 : 1 : 93.59 : 2.73, and RLP-3a was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with the ratio of 6.04 : 26.51 : 2.05 : 1 : 3.17 : 31.77. The NMR analyses revealed that RLP-1a, RLP-2a, and RLP-3a contained 6, 4, and 6 types of glycosidic linkages, respectively. RLP-1a and RLP-3a exhibited distinct antioxidant abilities on the superoxide anions, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and hydroxyl radicals in vitro. RLPs could decrease the serum lipid levels, elevate the serum high-density lipoprotein cholesterol levels, enhance the antioxidant enzymes levels, and upregulate of FADS2, ACOX3, and SCD-1 which involved in the lipid metabolic processes and oxidative stress in the high-fat diet-induced rats. These results suggested that RLPs ameliorated the high-fat diet- (HFD-) induced lipid metabolism disturbance in the rat liver through the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Low molecular weight polysaccharides of RLP could be served as a novel potential functional food for improving hyperlipidemia and liver oxidative stress responses.

Liquid Rubbers—General Rubber Products Technology

1971 ◽  
Vol 44 (3) ◽  
pp. 750-757 ◽  
Author(s):  
J. R. Pyne
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Raw Material ◽  
Development Work ◽  
Low Molecular Weight ◽  
Scale Production ◽  
Theoretical Possibility ◽  
High Molecular Weight Form ◽  
End Groups ◽  
Molecular Weight Form

Abstract Mixing and processing methods used in the rubber industry have been designed to use the only form of raw rubber hitherto available—that of a high molecular weight solid. But rubber in high molecular weight form is essential only in the finished product; in principle, similar final properties could be obtained from a low molecular weight raw material provided this could be chain extended before or during the final shaping and vulcanizing operation. This approach has been employed for some time in the rather specialized field of castable polyurethane rubber manufacture. Its exploitation for more general rubber manufacture has become more than just a theoretical possibility with the recent availability of “liquid rubbers” whose molecules have reactive end groups. Those available at present may well prove not fully acceptable, either economically or technically, but it is most unlikely that they represent the best that can be achieved. Material developments will be encouraged if means have been worked out for exploiting liquid rubbers' potential advantages (such as the ability to be processed on lighter and less powerful equipment), and the shortcomings of existing examples have been identified. These considerations led RAPRA to start a processing and compounding study—a decision which seems further justified by the very recent American announcements of development work on a tire manufacturing process using liquid rubber, and of full commerical scale production of several hydroxyl terminated liquid butadiene polymers. This report summarizes the study to date.

scholarly journals Low-temperature alkali-anthraquinone pretreatment of wheat straw: Gradual dissolution of lignin and carbohydrate retention in pretreated solids

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 8550-8564
Author(s):  
Lilong Zhang ◽  
Keli Chen
Keyword(s):  
Molecular Weight ◽  
Wheat Straw ◽  
Black Liquor ◽  
Compositional Analysis ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
Low Molecular Weight ◽  
Lignin Fraction ◽  
Intermediate Value ◽  
Comprehensive Study

This paper presents a comprehensive study of wheat straw that was alkali-pretreated with NaOH loadings from 60 to 220 mg NaOH/g dry straw and a 0.5% anthraquinone (AQ) loading at 90 °C for 1, 2, and 3 h. Images of the residual solids were taken with a scanning electron microscope. A full compositional analysis of the raw material and residual solids, yield of compounds dissolved in the black liquor (BL), and molecular weight (Mw) after the different pretreatments were presented to track the dissolution process of lignin and carbohydrates. The ratio of the lignin fraction to carbohydrates dissolved in the BL was used for an analysis of the reaction selectivity. The cellulose retained 90% of the carbohydrates in the pretreated straw, while 75% of the lignin was dissolved in the BL gradually with an intermediate value of Mw. Low-molecular weight lignin (Mw ~ 1800 and degree of polymerization ~ 1.05) was dissolved out with the 60 mg NaOH/g dry straw loading. When the NaOH loading was increased to 220 mg NaOH/g dry straw, the Mw of the lignin was 4300 to 4700.

Spectroscopic analysis (IR, Raman and 1H NMR) of low molecular weight organic fraction extracted from soil

1999 ◽  
pp. 587-588
Author(s):  
O. Francioso ◽  
S. Sánchez-Cortés ◽  
C. Ciavatta ◽  
C. Marzadori ◽  
J. V. García-Ramos ◽  
...  
Keyword(s):  
Molecular Weight ◽  
1H Nmr ◽  
Spectroscopic Analysis ◽  
Low Molecular Weight ◽  
Organic Fraction

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment

Venous thromboembolism in a general hospital. An update with low molecular weight heparin prophylaxis

VASA ◽  
2007 ◽  
Vol 36 (1) ◽  
pp. 17-22
Author(s):  
Schulz ◽  
Kesselring ◽  
Seeberger ◽  
Andresen
Keyword(s):  
Molecular Weight ◽  
Pulmonary Embolism ◽  
Venous Thromboembolism ◽  
Low Molecular Weight ◽  
Trauma Patients ◽  
Vte Prophylaxis ◽  
Vein Thrombosis ◽  
Patients At Risk ◽  
Hospital Stays ◽  
Event Rates

Background: Patients admitted to hospital for surgery or acute medical illnesses have a high risk for venous thromboembolism (VTE). Today’s widespread use of low molecular weight heparins (LMWH) for VTE prophylaxis is supposed to have reduced VTE rates substantially. However, data concerning the overall effectiveness of LMWH prophylaxis is sparse. Patients and methods: We prospectively studied all patients with symptomatic and objectively confirmed VTE seen in our hospital over a three year period. Event rates in different wards were analysed and compared. VTE prophylaxis with Enoxaparin was given to all patients at risk during their hospital stay. Results: A total of 50 464 inpatients were treated during the study period. 461 examinations were carried out for symptoms suggestive of VTE and yielded 89 positive results in 85 patients. Seventy eight patients were found to have deep vein thrombosis, 7 had pulmonary embolism, and 4 had both deep venous thrombosis and pulmonary embolism. The overall in hospital VTE event rate was 0.17%. The rate decreased during the study period from 0.22 in year one to 0,16 in year two and 0.13 % in year three. It ranged highest in neurologic and trauma patients (0.32%) and lowest (0.08%) in gynecology-obstetrics. Conclusions: With a simple and strictly applied regimen of prophylaxis with LMWH the overall rate of symptomatic VTE was very low in our hospitalized patients. Beside LMWH prophylaxis, shortening hospital stays and substantial improvements in surgical and anasthesia techniques achieved during the last decades probably play an essential role in decreasing VTE rates.

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