Characterization of the Pore Structure in Ice from Water Added at Different Temperatures

2019 ◽  
Vol 800 ◽  
pp. 289-292
Author(s):  
Andrejs Shishkin ◽  
Ieva Stafecka
Keyword(s):  
Cold Water ◽  
Flow Direction ◽  
Hot Water ◽  
Structure Characterization ◽  
Base Layer ◽  
Air Bubbles ◽  
Water Ice ◽  
Heat Flow Direction ◽  
Different Temperatures

The present study describes ice characterization technique by utilizing light microscopy. Two different optical setups were used and compared. For ice structure characterization, ice was formed by adding water to an ice base layer: pouring hot water (+20 °C), pouring cold water (+3 °C) and spraying of hot water (+20 °C) water. Ice substrate specimens were made (20 x 30 x 20 mm prepared in a polypropylene mould) at -20 °C for 48 h. The heat flow direction governed the orientation of the air bubbles, and set the inner structure of ice. Pouring hot water onto ice slowly solidified the top layer and created channel-like pores perpendicular to the top surface, but cold water quickly solidified the top layer and created chaotically oriented air bubbles.

scholarly journals Polysaccharides from Basidiocarps of Cultivating Mushroom Pleurotus ostreatus: Isolation and Structural Characterization

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2740 ◽  
Author(s):  
Ekaterina Baeva ◽  
Roman Bleha ◽  
Ekaterina Lavrova ◽  
Leonid Sushytskyi ◽  
Jana Čopíková ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Pleurotus Ostreatus ◽  
Cold Water ◽  
Water Soluble ◽  
Hot Water ◽  
Biologically Active ◽  
Alkaline Extract ◽  
A Cell ◽  
Oyster Mushrooms

Oyster mushrooms are an interesting source of biologically active glucans and other polysaccharides. This work is devoted to the isolation and structural characterization of polysaccharides from basidiocarps of the cultivated oyster mushroom, Pleurotus ostreatus. Five polysaccharidic fractions were obtained by subsequent extraction with cold water, hot water and two subsequent extractions with 1 m sodium hydroxide. Branched partially methoxylated mannogalactan and slightly branched (1→6)-β-d-glucan predominated in cold- and hot-water-soluble fractions, respectively. Alternatively, these polysaccharides were obtained by only hot water extraction and subsequent two-stage chromatographic separation. The alkali-soluble parts originating from the first alkali extraction were then fractionated by dissolution in dimethyl sulfoxide (DMSO). The polysaccharide insoluble in DMSO was identified as linear (1→3)-α-d-glucan, while branched (1→3)(1→6)-β-d-glucans were found to be soluble in DMSO. The second alkaline extract contained the mentioned branched β-d-glucan together with some proteins. Finally, the alkali insoluble part was a cell wall complex of chitin and β-d-glucans.

Analysis and Research on Natural Circulation Capacity of HFETR

2016 ◽  
Author(s):  
Taozhong Xu ◽  
Caiyu Deng ◽  
Yuxin Xiang
Keyword(s):  
Pressure Vessel ◽  
Cold Water ◽  
Flow Direction ◽  
Natural Circulation ◽  
Reactor Power ◽  
Hot Water ◽  
Forced Circulation ◽  
The Core ◽  
Establishment Process ◽  
Residual Heat

Natural circulation is being used as an important circulation to remove reactor residual heat. In the core of High Flux Engineering Trial Reactor of China (HFETR), the coolant is driven by pumps normally and flows from upside to downside in the core. When HFETR is shut down or runs in low power, the natural circulation between the hot water in the core and the cold water in the reflector inside the pressure vessel is established to cool down the core. Since the natural circulation processed only in the pressure vessel, the accident pumps need to be turned on periodically to remove reactor residual heat. The inversion of flow direction in HFETR and internal natural circulation lead to a different natural circulation establishment process from traditional reactor in which coolant flows form down to top normally. In this paper the transition between the natural circulation and forced circulation is analyzed by RELAP5/MOD3 code. The results showed that the accident pump could be turned off in the power of 850kW; The time, at which the accident pump needs to be turned on to transit the natural circulation to forced circulation, is decided by the temperature of the water in top of pressure vessel, and a formula between temperature of the water in the top of pressure vessel and the reactor power was obtained. The research results have theoretical and practical value to the full use of the natural circulation ability, as well as the safety of the engineering reactors or similar test facilities.

scholarly journals THE STRUCTURE CHARACTERIZATION OF ETHYLENE-PROPYLENE RANDOM COPOLYMERS FOR HOT WATER PIPING

2006 ◽  
Vol 006 (1) ◽  
pp. 177-179
Author(s):  
Meifang Guo ◽  
Yuping Dong ◽  
Honghong Huang ◽  
Jingchun Zhang ◽  
Qianshu Li
Keyword(s):  
Hot Water ◽  
Structure Characterization ◽  
Random Copolymers ◽  
Ethylene Propylene ◽  
Water Piping

scholarly journals Compatibility of Pretreated Coir Fibres (Cocos nuciferaL.) with Portland Cement to Produce Mineral Composites

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Joana M. Ferraz ◽  
Cláudio H. S. Del Menezzi ◽  
Mario R. Souza ◽  
Esmeralda Y. A. Okino ◽  
Sabrina A. Martins
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Cold Water ◽  
Cocos Nucifera ◽  
Chemical Characterization ◽  
Inhibition Test ◽  
Hot Water ◽  
Chemical Compatibility ◽  
Untreated Fibre

The objectives of the present work were to evaluate the chemical compatibility between coir (Cocos nuciferaL.) and cement and to study treatment methods to improve this compatibility. In the inhibition test, cement hydration temperature evolution was measured in the absence and presence of untreated and treated coir fibres (cold water, hot water and NaOH), besides the addition of 4% of CaCl2. The chemical characterization of untreated and treated coir fibres was done by determining the content of extractives, lignin, and holocellulose. The inhibition test graded the untreated fibre as “extreme inhibition,” ratifying the need to provide it a treatment. Treatments done on coir fibres affected positively the compatibility between cement and fibre, reducing the inhibition. The treatments reduced the lignin coir fibres’ and extractives proportion, whose variation was significantly correlated with the reduction of the inhibitory index. These results indicate a possibility for future incorporation of these fibres into the production of mineral composites.

scholarly journals EXPERIMENTAL STUDY OF HEAT TRANFER AUGMENTATION USING AIR BUBBLE INJECTION AND (Al2O3 /WATER) NANOFLUID FLOW IN DOUBLE PIPE HEAT EXCHANGERS

2021 ◽  
Vol 21 (2) ◽  
pp. 96-117
Author(s):  
Dhirgham A. Alkhafaji ◽  
Hameed K. Hamzah ◽  
Haider S. Hadi
Keyword(s):  
Heat Transfer ◽  
Cold Water ◽  
Volume Flow ◽  
Hot Water ◽  
Air Bubbles ◽  
Heat Transfer Characteristics ◽  
Flow Rates ◽  
Air Bubble ◽  
Double Pipe ◽  
Pipe Heat

In the present work, an experimental study on how to increase the heat transfer coefficient (HTC) in double pipe heat exchanger (DPHE) use of a variety of Al2O3 Nano-dispersion concentrations mixed in water as base fluid with air bubble injection for counter flow arrangement under turbulent flow conditions with (Re) Reynold number range from (6000 t0 45000) . The thermal performance of (DPHE) has been enhanced with the use of two techniques. The first, is represented by adding nanoparticles to hot water (inner pipe) raising the (HTC) inside the inner tube. Increase the volume concentration cause increase in the viscosity of the nanofluid leading to increase in friction factor .Secondly is represented by Air bubble injection in outer pipe with cold water to enhance the (HTC). The mobility of air bubbles inside the water from down to up by the force of the buoyancy, and the movement of these air bubbles results in significant mixture and turbulence within the water. The variations of number of thermal units (NTU), exergy loss, dimensionless exergy and (Nu) are evaluated. The investigated parameters were cold water volume flow rates (8, 10, 12 and14) l/min, flow in outer tube. Also, three different volume flow rates of air (12, 16 and 20) l/min mixed with water in outer tube. The volume flow rates of hot water remains constant at (8 l/min) flow in inner pipe with three volumetric concentrations of given nanofluid. The results showed that the air bubble injection throughout the tube gave maximum enhancement in heat transfer characteristics followed by the no air bubble injection. Since the enhancement in heat transfer characteristics varies linearly with the volumetric concentration of Nanofluids, Nanofluids with 0.3% of Al2O3 nanoparticles gave more enhancements in (HTC) than the case without nanofluid. The Nusselt number increased about (8% - 45%).  

scholarly journals Studies on Lectin Mediated Agglutination Reaction on Red Blood Cell Surface Antigens Using Hot and Cold Water Plant Extracts

2021 ◽  
pp. 48-52
Author(s):  
Bhavya Sahithi Velagapudi ◽  
Hemanth Sai Nannapaneni ◽  
Akanksha Alampally ◽  
Suryanarayana Veeravilli ◽  
Duggipogu Praveen Kumar ◽  
...  
Keyword(s):  
Cold Water ◽  
Surface Protein ◽  
Hot Water ◽  
Carbohydrate Binding ◽  
Cell Surface Antigens ◽  
Binding Properties ◽  
Cell Agglutination ◽  
Plant Lectins ◽  
Water Plant

Lectin has various physiological roles in cell agglutination, based on their carbohydrate-binding properties, plant lectins are widely used for the detection, segregation, and characterization of glycoconjugates. Rhesus (Rh) factor is a protein that is inherited and found on the surface of red blood cells. If the surface protein is present, the RBC is Rh positive; otherwise, it is Rh-negative in nature. In this paper, we use agglutination reactions to investigate the effect of different cold and hot water extracted plants on RBC antigens as an alternative to commercial monoclonal antibodies. Extensive research on the sequence homology and 3-D structure of various plant lectins suggests that they have been conserved throughout evolution and may play important physiological roles that are still unknown.

Fractional Isolation and Characterization of Polysaccharides from Oil Palm Trunk and Empty Fruit Bunch Fibres

Holzforschung ◽  
1999 ◽  
Vol 53 (3) ◽  
pp. 253-260 ◽  
Author(s):  
R. Sun ◽  
J.M. Fang ◽  
L. Mott ◽  
J. Bolton
Keyword(s):  
Oil Palm ◽  
Cell Walls ◽  
Cold Water ◽  
Syringic Acid ◽  
Hot Water ◽  
Empty Fruit Bunch ◽  
Coumaric Acid ◽  
Oil Palm Trunk ◽  
Isolation And Characterization

Summary The polysaccharides in oil palm trunk fibre and empty fruit bunch (EFB) fibre were fractionated into cold water solubles, hot water solubles, 1% NaOH solubles, and 17.5% NaOH soluble fractions. Cellulose (approximately 42%) and hemicelluloses (approximately 33%) were the major polysaccharides in the palm trunk fibre and EFB fibre. Extractions of the lignified fibres with cold water, hot water, and 1% NaOH produced the hemicellulosic fractions, which were enriched in xylose and glucose and to a lesser extent, arabinose-, galactose-, mannose-, rhamnose-, and ribose-containing polysaccharides, together with noticeable amounts of associated lignin (4.5–31.2%). Further extraction of the delignified fibre residues with aqueous 17.5% NaOH removed the hemicellulosic fractions, which were strongly enriched in xylose-containing polysaccharides and relatively free of associated lignin (0.3–0.7%). Eight phenolic acids and aldehydes, including p-hydroxybenzoic acid, p-hydroxybenzaldehyde, vanillic acid, syringic acid, vanillin, syringaldehyde, p-coumaric acid, and ferulic acid, were detected in the mixtures of alkaline nitrobenzene oxidation of associated lignin in all the sixteen polysaccharide fractions. The results obtained showed that hemicelluloses in the cell walls of oil palm trunk and EFB fibres, are mainly bonded with lignin by syringyl units.

XIII.—The Polysaccharides Synthesized by Monodus subterraneus when Grown on Artificial Media under Bacteria-free Conditions.

1962 ◽  
Vol 68 (3) ◽  
pp. 171-185 ◽  
Author(s):  
Anne Beattie ◽  
Elizabeth Percival
Keyword(s):  
Aqueous Ethanol ◽  
Cold Water ◽  
Periodate Oxidation ◽  
Hot Water ◽  
Unicellular Organism ◽  
Isolation And Characterization ◽  
Complete Extraction ◽  
Crude Polysaccharide ◽  
Monodus Subterraneus

SynopsisThis paper describes the isolation and characterization of the polysaccharides synthesized by the unicellular organism, Monodus subterraneus. Complete extraction of polysaccharide material proved difficult and the method finally adopted, after removal of colouring matter by immersion in dimethyl sulphoxide, was successive extractions with (i) cold water, (ii) hot water, (iii) aqueous ethanol, (iv) chlorite solution, and (v) dilute alkali. The major polysaccharide, isolated from (v), is a glucan. It was shown by periodate oxidation, methylation and enzymic studies to consist mainly of β-l, 4-linked glucose units. The presence of a small proportion of β-1, 3-linked glucose units, either incorporated with the β-1, 4-linked units in a single polymer of the lichenin-type or in a separate polymer of the laminarin-type, was also established. Further small quantities of this mixed glucan were also deposited from (ii) and from (iii) on keeping these extracts in the cold. Heterogeneous crude polysaccharide material was isolated from (i), (ii), (iii) and (iv) by alcohol precipitation. The sugars present in these various precipitates and their respective oxopolysaccharides were identified chromatographically, and, in the case of the major constituents, separated and characterized as crystalline derivatives. The polysaccharide extracted by cold water was found to contain glucose, mannose, galactose, xylose and 12 per cent of sulphate; that extracted by hot water comprised glucose (major), galactose (major), and possibly fucose; and that extracted by chlorite solution consisted of glucose (major), xylose (major), ribose and a trace of galactose.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

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