scholarly journals Chemical composition profiles during alkaline flooding at different temperatures and extended residence times

1992 ◽  
Author(s):  
R Aflaki ◽  
L Handy
Keyword(s):  
Chemical Composition ◽  
Residence Times ◽  
Different Temperatures ◽  
Composition Profiles

scholarly journals Changes of Physicochemical Properties of Starch Syrups Recommended for Winter Feeding of Honeybees during Storage

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 374
Author(s):  
Teresa Szczęsna ◽  
Ewa Waś ◽  
Piotr Semkiw ◽  
Piotr Skubida ◽  
Katarzyna Jaśkiewicz ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Physicochemical Parameters ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Different Temperatures ◽  
And Storage ◽  
Bee Colonies ◽  
Temperature Time ◽  
Winter Feeding

The aim of this study was to determine the influence of storage temperature and time on physicochemical parameters of starch syrups recommended for the winter feeding of bee colonies. The studies included commercially available three starch syrups and an inverted saccharose syrup that were stored at different temperatures: ca. 20 °C, 10–14 °C, and ca. 4 °C. Physicochemical parameters of fresh syrups (immediately after purchase) and syrups after 3, 6, 9, 12, 15, 18, 21, and 24 months of storage at the abovementioned temperatures were measured. It was observed that the rate of unfavorable changes in chemical composition of starch syrups and the inverted saccharose syrup, mainly the changes in the 5-hydroxymethylfurfural (HMF) content, depended on the type of a syrup and storage conditions (temperature, time). Properties of tested starch syrups intended for winter feeding of bees stored at ca. 20 °C maintained unchanged for up to 6 months, whereas the same syrups stored at lower temperatures (10–14 °C) maintained unchanged physicochemical parameters for about 12 months. In higher temperatures, the HMF content increased. To date, the influence of this compound on bees has not been thoroughly investigated.

scholarly journals Effects of natamycin and Lactobacillus plantarum on the chemical composition, microbial community, and aerobic stability of Hybrid pennisetum at different temperatures

RSC Advances ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 8692-8702 ◽  
Author(s):  
Assar Ali Shah ◽  
Chen Qian ◽  
Juanzi Wu ◽  
Zhiwei Liu ◽  
Salman Khan ◽  
...  
Keyword(s):  
Microbial Community ◽  
Chemical Composition ◽  
Lactobacillus Plantarum ◽  
Aerobic Stability ◽  
Different Temperatures ◽  
Fermentation Quality ◽  
Hybrid Pennisetum

The inoculation of L. plantarum and natamycin influenced the fermentation quality. Natamycin and L. plantarum reduced the undesirable microbial community. During ensiling process, the LA and LABs was significantly enhanced.

Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Thermal Stability Of

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

scholarly journals Effects of Chemical Composition and Austenite Deformation on the Onset of Ferrite Formation for Arbitrary Cooling Paths

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 540 ◽  
Author(s):  
Aarne Pohjonen ◽  
Mahesh Somani ◽  
David Porter
Keyword(s):  
Phase Transformation ◽  
Chemical Composition ◽  
Hardened Steel ◽  
Computational Method ◽  
Alloying Elements ◽  
Continuous Cooling Transformation ◽  
Ferrite Formation ◽  
Continuous Cooling ◽  
Different Temperatures ◽  
Range Of Values

We present a computational method for calculating the phase transformation start for arbitrary cooling paths and for different steel compositions after thermomechanical treatments. We apply the method to quantitatively estimate how much austenite deformation and how many different alloying elements affect the transformation start at different temperatures. The calculations are done for recrystallized steel as well as strain hardened steel, and the results are compared. The method is parameterized using continuous cooling transformation (CCT) data as an input, and it can be easily adapted for different thermomechanical treatments when corresponding CCT data is available. The analysis can also be used to obtain estimates for the range of values for parameters in more detailed microstructure models.

Ion–ion–solvent interactions in aqueous ionic cosolvent systems. III. Thermodynamics of hydrogen bromide and hydrogen iodide from water to aqueous solutions of sodium nitrate from emf measurements at different temperatures and the structuredness of the solvents

1987 ◽  
Vol 65 (12) ◽  
pp. 2843-2848
Author(s):  
Sibaprasad Rudra ◽  
Himansu Talukdar ◽  
Kiron K. Kundu
Keyword(s):  
Sodium Nitrate ◽  
Structural Changes ◽  
Hydrogen Bromide ◽  
Scaled Particle Theory ◽  
Relative Order ◽  
Emf Measurements ◽  
Solvent Interactions ◽  
Different Temperatures ◽  
Composition Profiles ◽  
The Individual

Standard free energies [Formula: see text] and entropies [Formula: see text] of transfer of hydrogen bromide and iodide from water to the aqueous 1, 2, and 4 m of sodium nitrate have been determined by measuring the emf's of the cell: Pt, H2(g, 1 atm)/KOH(m1), KX(m2), solvent/AgX–Ag where X = Br or I at five equidistant temperatures ranging from 15–35°C. [Formula: see text] values of HBr, HI as well as that of HCl obtained from earlier paper and particularly of the individual ions [Formula: see text](i), obtained by use of modified TATB assumption reported earlier and also [Formula: see text](i) obtained after correcting for "cavity" effect and Born-type electrostatic effect estimated tentatively by the scaled particle theory (SPT) and simple Bom equation, respectively, reveal the relative order of stabilisation of Cl−, Br−, and I− ions. Analysis of [Formula: see text]–composition profile (X = Cl, Br, and I) exhibits a characteristic "maxima" around 1.5 m NaNO3 with the relative order HI > HBr > HCl in the region of maxima. Moreover, dissection of [Formula: see text] values into the individual ion contributions by use of the modified TATB assumption reported earlier, results in the characteristic "maxima" around 1.5 m NaNO3 in [Formula: see text] or [Formula: see text]–composition profiles for H+ and "minima" for Cl−, Br−, and I−. The results are discussed in terms of ion–ion–solvent interactions as well as the structural changes of the solvents.

Microstructural Developments During Implantation of Metals

1983 ◽  
Vol 27 ◽  
Author(s):  
D. I. Potter ◽  
M. Ahmed ◽  
S. Lamond
Keyword(s):  
Chemical Composition ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Auger Spectroscopy ◽  
Phase Region ◽  
Dislocation Loops ◽  
Two Phase ◽  
Model Calculations ◽  
Near Surface ◽  
Composition Profiles

ABSTRACTThe chemical and microstructural changes caused by the direct implantation of solutes into metals are examined. The particular case involving Al+-ion implantation into nickel is treated in detail. Chemical composition profiles measured using Auger spectroscopy and Rutherford backscattering, and average near-surface chemical composition measured using an analytical electron microscope, are compared with model calculations. The microstructures that develop during implantation are investigated using transmission electron microscopy. For low fluences implanted near room temperature, these microstructures contain dislocations and dislocation loops. Dislocation loops, dislocations, and voids result from implantations at temperatures near 500°C. Higher fluences at these elevated temperatures produce precipitates when the composition of implanted solute lies in a two-phase region of the phase diagram. Implanted concentrations corresponding to intermetallic compounds produce continuous layers of these compounds. Room temperature, as compared to elevated temperature, implantation may produce the same phases at the appropriate concentrations, e.g. β'-NiAl, or different phases, depending on the relative stability of the phases involved.

Thermodynamics of transfer of glycine, diglycine, and triglycine from water to aqueous solutions of urea, glycerol, and sodium nitrate

1988 ◽  
Vol 66 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Himansu Talukdar ◽  
Sibaprasad Rudra ◽  
Kiron K. Kundu
Keyword(s):  
Sodium Nitrate ◽  
Regular Function ◽  
Scaled Particle Theory ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Thermodynamics Of Transfer ◽  
Different Temperatures ◽  
Composition Profiles ◽  
Cavity Effect ◽  
Nitrate Solutions

Standard free energies [Formula: see text] and entropies [Formula: see text] of transfer of glycine (G), diglycine (DG), and triglycine (TG), from water to aqueous mixtures of glycerol (GL) and urea (UH) have been determined from solubility measurements at different temperatures. This was also extended to an ionic cosolvent system like aqueous sodium nitrate solutions for G and DG. The observed [Formula: see text] and [Formula: see text]–composition profiles, as well as those obtained after correcting for the "cavity effect" as estimated by scaled particle theory (SPT), were examined in the light of various interactions. The corrected [Formula: see text]and [Formula: see text] values show a regular function of the peptide chain length of the amino acids and impart useful information regarding the involved relative structural effects of these ionic and non-ionic cosolvents.

The accuracy of quantitative LEED in determining chemical composition profiles of substitutionally disordered alloys: a case study

1998 ◽  
Vol 416 (3) ◽  
pp. 423-429 ◽  
Author(s):  
M Sporn ◽  
E Platzgummer ◽  
S Forsthuber ◽  
M Schmid ◽  
W Hofer ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Disordered Alloys ◽  
Composition Profiles

Influence of chemical composition of nanocrystalline iron’s surface on the rates of two parallel reactions: nitriding and catalytic decomposition of ammonia

2012 ◽  
Vol 66 (1) ◽  
Author(s):  
Rafał Pelka ◽  
Walerian Arabczyk
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Iron Catalyst ◽  
Catalytic Decomposition ◽  
Ammonia Decomposition ◽  
Nitriding Process ◽  
Potassium Oxide ◽  
Different Temperatures ◽  
Parallel Reactions ◽  
Different Content

AbstractInfluence of chemical composition of nanocrystalline iron’s surface on its activity in the nitriding process of iron and catalytic decomposition of ammonia was studied. The rate of the nitriding reaction was measured by the thermogravimetric method using a tubular differential reactor. Hydrogen concentration in the reactor was also measured. The rate of the catalytic decomposition of ammonia was determined using the reactor’s mass balance. Experiments were conducted at different temperatures within the range from 300°C to 525°C. Iron catalyst for ammonia synthesis was studied. Two sorts of samples with a different content of potassium oxide (0.16 mass % and 0.64 mass % of K2O) were used. The composition of samples from the second group was modified by an addition of different amounts of sulfur. At temperatures above 400°C, when the effect of ammonia decomposition on the gas phase composition was experimentally measured, the presence of potassium and sulfur on the iron surface influenced the rate of the iron nitriding process. The ammonia decomposition rate was higher for samples with a greater amount of potassium. The rate of reactions depended also on the sulfur concentration and dropped when the sulfur content increased. The value of apparent activation energy of ammonia decomposition was in the range of 150 kJ mol−1 to 180 kJ mol−1 while the content of sulfur in the samples increased.

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