Factors affecting the solubility of gypsum: II. Effect of sodium hydroxide under various conditions

2007 ◽  
Vol 35 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Hanaa Y. Ghorab ◽  
Safaa H. Abou El Fetouh
Keyword(s):  
Sodium Hydroxide ◽  
Factors Affecting

Factors Affecting the Compressive Strength of Class C Fly Ash Geopolymer

2011 ◽  
Vol 99-100 ◽  
pp. 960-964 ◽  
Author(s):  
Xue Ying Li ◽  
En Zu Zheng ◽  
Chun Long Ma
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Delay Time ◽  
Curing Temperature ◽  
Mixed Solution ◽  
Mass Ratio ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Class C

The compressive strength of geopolymer prepared from a class C fly ash (CFA) at different curing conditions and mass ratio of water to fly ash were investigated. The geopolymer was activated with a mixed solution of sodium hydroxide (NaOH) and sodium silicate. The results revealed that the obtained compressive strength was in the range of 11.7~61.9MPa and the compressive strength decreased with the increment of the mass ratio of water to CFA (W/F). The geopolymer samples with the highest strength were obtained when W/F was 0.30 with proper delay time 1d before being demoulded and then followed by curing at 60°C for 24h. For geopolymer with lower W/F (0.30), its optimum curing temperature was better not higher than 60°C, however, for the higher W/F, the curing temperature was suit to more than 70°C.

scholarly journals Making Biodegradable Seedling Pots from Textile and Paper Waste—Part A: Factors Affecting Tensile Strength

2021 ◽  
Vol 18 (13) ◽  
pp. 6964
Author(s):  
Jeanger P. Juanga-Labayen ◽  
Qiuyan Yuan
Keyword(s):  
Tensile Strength ◽  
Sodium Bicarbonate ◽  
Sodium Hydroxide ◽  
Alkali Treatment ◽  
Compressive Load ◽  
Factors Affecting ◽  
Paper Waste ◽  
Binding Agents ◽  
Compressive Loads ◽  
Corrugated Cardboard

This study investigates the efficacy of using discarded textile (cotton and polycotton) and paper waste (newspaper and corrugated cardboard) as substrates to form sheets with optimum tensile strength. The effect of alkali treatment (sodium hydroxide (NaOH) and sodium bicarbonate (NaHCO3)), compressive loads (200 N and 500 N), and the use of binding agents (blackstrap molasses, sodium alginate, and cornstarch) were studied to optimize the tensile strength of homogeneous sheets. The alkali treatment using 5% NaOH for 5 h of soaking demonstrated the highest increase in tensile strength of 21% and 19% for cotton and newspaper, respectively. Increasing compressive load from 200 N to 500 N showed the highest increase in tensile strength of 37% and 42% for cotton and newspaper, respectively. Remarkably, among the binders, cornstarch at 20% concentration obtained an increase in tensile strength of 395%, 320%, 310%, and 185% for cotton, polycotton, corrugated cardboard, and newspaper sheets, respectively. The optimum results obtained from this study will be utilized to develop biodegradable seedling pots using discarded textile and paper waste.

Epitaxial Chemical Deposition of ZnO Nanocolumns from NaOH Solutions

2004 ◽  
Vol 822 ◽  
Author(s):  
Renee B. Peterson ◽  
Clark L. Fields ◽  
Brian A. Gregg
Keyword(s):  
Crystal Growth ◽  
Sodium Hydroxide ◽  
Chemical Deposition ◽  
New Method ◽  
Growth Theory ◽  
Complexing Agents ◽  
Factors Affecting ◽  
Coated Glass ◽  
Bare Glass ◽  
Substrate Cleaning

AbstractA new method of depositing epitaxial ZnO nanocolumns on sputter-coated ZnO substrates is described that utilizes supersaturated zincate species in sodium hydroxide solutions and requires no complexing agents. Uniform arrays of columns are grown reproducibly over entire substrates in 10 to 50 min. Columns are 50 to 2000 nm long and 50 to 100 nm wide. Strict substrate cleaning and/or preparations are not necessary with this method, in contrast to many other techniques. Films grow only on substrates pre-coated with ZnO, not on bare glass or ITOor SnO2-coated glass. Factors affecting the column growth are elucidated and experimental observations are correlated with crystal growth theory.

scholarly journals Factors Affecting Seed Germination of Ilex latifolia and I. rotunda

HortScience ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 352-356 ◽  
Author(s):  
Takahiro Tezuka ◽  
Hisa Yokoyama ◽  
Hideyuki Tanaka ◽  
Shuji Shiozaki ◽  
Masayuki Oda
Keyword(s):  
Seed Germination ◽  
Sodium Hydroxide ◽  
Immature Embryos ◽  
Cold Stratification ◽  
In Vitro Germination ◽  
Factors Affecting ◽  
Mature Seeds ◽  
Mechanical Barrier ◽  
Good Germination

Mature seeds of Ilex species usually contain immature embryos and are extremely difficult to germinate. Ilex latifolia and I. rotunda, two species that are grown as ornamentals, also produce seeds that are difficult to germinate. In the present study, we investigated some factors affecting seed germination in those species. Although seeds of I. latifolia and I. rotunda could imbibe water, they did not germinate. When embryos were cultured in vitro, germination was observed in I. latifolia but not in I. rotunda. Interestingly, a transient decrease in germination frequency occurred in I. latifolia embryos isolated from seeds collected in September or October. Among five types of I. latifolia seeds that differed in the presence of the endocarp, testa, and endosperm, germinability of isolated embryos was highest. Good germination was also observed in quarter-seeds with or without endocarp followed by half-seeds. Treatment of seeds with sodium hydroxide (NaOH) had no effect on seed germination in I. latifolia. Cold stratification at 5 °C increased the germination frequency of I. latifolia embryos. In conclusion, the data suggested a mechanical barrier by the endocarp and inhibitors contained in the endosperm, testa, and/or endocarp inhibited seed germination in I. latifolia. Although no seeds or embryos of I. rotunda germinated, cold stratification in combination with other treatments deserves further investigation. Chemical name: sodium hydroxide (NaOH).

Comparison of Acrylamide and Agar Gels by Freeze-Etching

1977 ◽  
Vol 35 ◽  
pp. 606-607
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Electron Microscope ◽  
Sodium Hydroxide ◽  
Sodium Hypochlorite ◽  
Chromic Acid ◽  
Distilled Water ◽  
Thin Sheets ◽  
Acid Cleaning ◽  
Agar Gels ◽  
Freeze Etching ◽  
Water Cut

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

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