Formation of NaxFeO2 by the oxidation of iron powder in concentrated sodium hydroxide solutions at elevated temperatures

1995 ◽  
Vol 14 (9) ◽  
pp. 633-634 ◽  
Author(s):  
S. Uchida ◽  
T. Sato ◽  
A. Okuwaki
Keyword(s):  
Sodium Hydroxide ◽  
Iron Powder ◽  
Elevated Temperatures

Extraction increase of coals treated with alcohol-sodium hydroxide at elevated temperatures

Fuel ◽  
1978 ◽  
Vol 57 (5) ◽  
pp. 289-292 ◽  
Author(s):  
Masataka Makabe ◽  
Yasuo Hirano ◽  
Koji Ouchi
Keyword(s):  
Sodium Hydroxide ◽  
Elevated Temperatures

Caustic Cracking: Stress-Corrosion Tests in Sodium Hydroxide Solutions at Elevated Temperatures

1950 ◽  
Vol 163 (1) ◽  
pp. 18-26 ◽  
Author(s):  
C. D. Weir
Keyword(s):  
Stress Corrosion ◽  
Sodium Hydroxide ◽  
Anodic Polarization ◽  
Elevated Temperatures ◽  
Cathodic Polarization ◽  
External Surface ◽  
High Concentration ◽  
Notched Specimens ◽  
Lever System ◽  
Fine Grain

The paper describes a series of tests carried out using an apparatus specially designed for stress-corrosion investigations at high temperatures. The specimens, which were of hollow form, were inserted into the base of an autoclave and loaded by means of a lever system, through a push rod inserted in the specimen. This arrangement permitted the production of accurate notch-forms on the external surface in contact with the sodium hydroxide solutions. It was found possible to produce failure of notched specimens rapidly and consistently, but homogeneously stressed specimens were immune. The fractures were intercrystalline and typical of those occurring in practice. Dilute solutions, though not entirely impotent, were found to be very much less effective than those of high concentration. The presence (or absence) of silica in the solutions exerted no appreciable influence. Neither the addition of tannin nor the use of fine-grain steels was completely effective in preventing intercrystalline failure, though in the case of the latter, increased resistance was noted in some cases. Cathodic polarization was found to be protective while anodic polarization did not prevent, and possibly hastened, failure.

scholarly journals Influence of Content and Microstructure of Deposited Carbon on Fluidization Behavior of Iron Powder at Elevated Temperatures

2014 ◽  
Vol 54 (3) ◽  
pp. 589-595 ◽  
Author(s):  
Chao Lei ◽  
Tao Zhang ◽  
Jianbo Zhang ◽  
Chuanlin Fan ◽  
Qingshan Zhu ◽  
...  
Keyword(s):  
Iron Powder ◽  
Elevated Temperatures

scholarly journals Effect of Low Temperatures and Residence Times of Pretreatment on Glucan Reactivity of Sodium Hydroxide-Pretreated Rice Straw

2017 ◽  
Vol 15 (4) ◽  
pp. 313-323
Author(s):  
Supaporn SOPHONPUTTANAPHOCA ◽  
Kontawan SIRIGATMANEERAT ◽  
Kulphaphorn KRUAKRUT
Keyword(s):  
Sodium Hydroxide ◽  
Rice Straw ◽  
Elevated Temperatures ◽  
Total Solid ◽  
Future Research ◽  
Residence Times ◽  
Simple Method ◽  
Lignin Removal ◽  
Pretreatment Time ◽  
Pretreatment Conditions

Alkaline pretreatment of lignocellulosic biomass is an approach to enhance the susceptibility of the biomass that is subsequently converted into fermentable sugars. The efficacy of the sodium hydroxide pretreatment of rice straw RD41 was evaluated in terms of total solid removal, lignin removal, glucan recovery, and glucan conversion yields. The pretreatment conditions were 50, 60, 70, 80, and 100 °C, and each temperature kept for 1 to 5 h. The effect of pretreatment temperatures was more pronounced than that of the pretreatment times. The elevated temperatures caused higher total solid removal and lignin removal. The highest total solid removal (52.5 to 55.8 %) was found in the pretreatment at 100 °C. At this temperature, the highest lignin removal (~87 %) could be obtained regardless of the residence times of the pretreatment. Most of the glucan (~80 to 100 %) was preserved in the pretreated rice straw. Lower temperatures (50 and 60 °C) favored higher glucan preservation (> 90 %) in the pretreated solids. Glucan conversion of the 3 h pretreatment time samples of each pretreatment temperature revealed that more than 80 % of glucan conversion could be accounted for in samples pretreated at 70 to 100 °C within 24 h of saccharification. The lower temperatures required a prolonged pretreatment time to reach a higher glucan conversion (~90 %), as found in the 50 °C, 5 h pretreated rice straw. The optimal conditions of this simple method are economically feasible, and can be applied to testing the reactivity of herbaceous lignocellulose in future research.

DEGRADATION OF D-GLUCOSE-1-C14 TO TRIOSE-REDUCTONE-C14

1955 ◽  
Vol 33 (12) ◽  
pp. 1824-1828 ◽  
Author(s):  
H. F. Bauer ◽  
Carol Teed
Keyword(s):  
Sodium Hydroxide ◽  
Lead Acetate ◽  
Reducing Sugars ◽  
Elevated Temperatures ◽  
Formation Mechanisms ◽  
Glucose Molecule ◽  
Glycerol Formation

Triose-reductone-C14 was obtained by treating D-glucose-1-C14 with sodium hydroxide in the presence of lead acetate at elevated temperatures. Carbon atoms four, five, and six, as well as carbon atoms one, two, and three, of the D-glucose molecule are shown to contribute to the triose-reductone yield. The formation of triose-reductone was found not to be accompanied by glycerol formation. Mechanisms for fragmentation of reducing sugars are discussed in the light of these findings.

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.

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

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