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 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.

The Role of Temperature on Hydration of Binary System of Metakaolin/Portland Cement

2016 ◽  
Vol 851 ◽  
pp. 51-56 ◽  
Author(s):  
Martin Boháč ◽  
Radoslav Novotný ◽  
Jakub Tkacz ◽  
Miroslava Hajdúchová ◽  
Martin Palou ◽  
...  
Keyword(s):  
Binary System ◽  
Portland Cement ◽  
Isothermal Calorimetry ◽  
Chemical Characterization ◽  
Exothermic Peak ◽  
Early Hydration ◽  
Different Temperatures ◽  
C 50

The role of temperature of metakaolin/Portland cement binary system was studied by isothermal calorimetry. Sample with 50 % of metakaolin replacement were monitored at 30 °C, 40 °C, 50 °C and 60 °C. Structural and chemical characterization of hardened pastes was obtained by scanning electron and Raman microscopy. Paper deals with kinetics of main exothermal reactions during early hydration of the system. Activation energies were calculated for processes related to each exothermic peak. The nature of hydration products at different temperatures was revealed by microstructural studies.

scholarly journals Effects of pressurized hot water extraction on the yield and chemical characterization of pectins from Campomanesia xanthocarpa Berg fruits

2020 ◽  
Vol 146 ◽  
pp. 431-443 ◽  
Author(s):  
Isabela Pereira Dias ◽  
Shayla Fernanda Barbieri ◽  
Damian Estuardo López Fetzer ◽  
Marcos Lúcio Corazza ◽  
Joana Léa Meira Silveira
Keyword(s):  
Chemical Characterization ◽  
Hot Water ◽  
Water Extraction ◽  
Hot Water Extraction ◽  
Pressurized Hot Water Extraction

Characterization of microemulsions formulated from naturally and chemically extracted oils from Cocos nucifera Linne

2020 ◽  
Vol 16 (1) ◽  
pp. 39-48
Author(s):  
O.A. Adetunji ◽  
B. Adesanwo ◽  
O.A. Odeniyi
Keyword(s):  
Castor Oil ◽  
Cocos Nucifera ◽  
Antimicrobial Properties ◽  
Coconut Oil ◽  
Tween 80 ◽  
Antimicrobial Activities ◽  
Oil Extraction ◽  
Hot Water ◽  
Copper Zinc

Background: Oil derived from Cocos nucifera Linne (CNL) has been used in formulating creams; however, its use in formulation of microemulsion is not well documented in literature.Objective: Oils obtained from CNL were characterized, used in the formulation of microemulsions and were evaluated for their antimicrobial properties in comparison with Castor oil BP (CO) and commercially available coconut oil (CACO).Methodology: Oil from CNL was extracted by maceration in hot – water and petroleum ether to yield naturally extracted oil (NEO) and chemically extracted oil (CEO) respectively. The NEO and CEO were used in formulating microemulsions containing pre-determined ratios (3:7, 1:1, 9:1) of oil to surfactant mix (Smix) [containing polyethylene glycol: Tween 80® at ratio 2:1] Characterization of NEO, CEO and microemulsions were carried out using elemental constituents, rheology, physico-and phyto-chemical analysis, thermal stability and antimicrobial profiles as parameters. Statistical analysis was done using ANOVA at p<0.05Results: The NEO and CEO contained antraquinones and terpenoids, but were devoid of lead, copper, zinc, alkaloids, saponins, cardiac glycosides and flavonoids. Viscosity profiles were in the order CO>CEO>CACO>NEO. The microemulsions were in the size range 54.24±0.26-89.08±0.07 μm. Microemulsions of oil:Smix (3:7) were the most stable. Inhibition ranking was Candida sp.D25 (CEO:Smix>CACO: Smix>NEO: Smix>NEO>CO>CEO), Candida sp.D33 (CEO = CO>CACO: Smix=NEO>CEO:Smix=NEO:Smix), Staphylococcus sp.DS2 (NEO>CO>CACO:Smix>NEO: Smix>CEO: Smix=CEO) and Pseudomonas sp.DP8 (NEO:Smix>CO>CACO:Smix>CEO:Smix=NEO > CEO).Conclusion: Oil derived from CNL has good potentials as an excipient in the formulation of microemulsions and the method of oil extraction had a significant effect on the antimicrobial activities and on the microemulsions formulated using the oils. Keywords: Coconut oil, extraction method, castor oil, microemulsions, antimicrobial properties.

scholarly journals Physical-Chemical Characterization of Fermented Coconut Water (Cocos nucifera L)

2020 ◽  
Vol 7 (5) ◽  
pp. 247-255
Author(s):  
Alexandre Santos de Souza ◽  
Janclei Pereira Coutinho ◽  
Lara Bruna Brito Castro de Souza ◽  
Daiane Pereira Barbosa ◽  
André Luiz Sampaio da Silva Júnior ◽  
...  
Keyword(s):  
Cocos Nucifera ◽  
Chemical Characterization ◽  
Coconut Water ◽  
Physical Chemical ◽  
Cocos Nucifera L

scholarly journals Multi-Factor Diagnostic and Recommendation System for Boron in Neutral and Acidic Soils

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 410 ◽  
Author(s):  
Richardly Lenz Clove Dupré ◽  
Lotfi Khiari ◽  
Jacques Gallichand ◽  
Claude Alla Joseph
Keyword(s):  
Recommendation System ◽  
Learning Algorithm ◽  
Chemical Characterization ◽  
Automatic Machine ◽  
Hot Water ◽  
Hot Water Extraction ◽  
The Third ◽  
Crop Type ◽  
Yield Responses

Despite its inconveniences, the most recognized method to extract boron from soils is that of hot water extraction (BHW), which is used for diagnostics and recommendations. However, the Mehlich-3 (M3) method is widely used to extract and diagnose several elements at once (P, K, Ca, Mg, Al, B, Cu, Zn, Fe, and Mn) and is well adapted to routine analyses. The objective of our study was to develop a soil diagnostic and recommendation system for boron as a function of measured BM3 (and other interacting elements), crop type, and spreading methods. This system is based on three databases from either the international literature or the chemical characterization of acidic-to-neutral soils typical from Québec (Canada). The first database came from the characterization of 365 samples typical of Québec soils; it has been used to predict, by the AutoML (Automatic Machine Learnig) supervised learning algorithm, BM3 as a function of a set of parameters from the following: BHW, pHW, organic carbon (OC), CaM3, KM3, and MgM3. Depending on the parameters used, the R2 between the measured and observed BM3 varied from 0.36 to 0.99. This database allowed us to define two classifications for soil boron diagnostics and fertility evaluation. The Cate–Nelson analysis for these two models allowed us to define three boron fertility classes: Low, medium and high; that is 0.00–0.23, 0.23–0.58, and 0.58–3.70 mg B kg−1, respectively, for BHW, and 0.00–0.65, 0.65–1.03, and 1.03–12.70 mg B kg−1, respectively, for BM3. The third database was extracted from 130 yield responses to increasing levels of boron; it was used to define a recommendation model for boron, based on AutoML, as a function of BM3, pHW, the crop boron requirement (medium, high), and the type of spreading (broadcast, sidedress, foliar spraying). This model resulted in an R2 of 0.63.

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.

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