The influence of reaction conditions on the course of electrolytic preparation of ammonium peroxodisulphate: The influence of the relative degree of saturation of starting solution and of the temperature

1981 ◽  
Vol 46 (11) ◽  
pp. 2795-2808 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová ◽  
Hana Špalková
Keyword(s):  
Electrolytic Cell ◽  
Maximum Allowable Concentration ◽  
Degree Of Saturation ◽  
Effect Of Temperature ◽  
Current Yield ◽  
Concentrated Solutions ◽  
Reaction Conditions ◽  
Starting Solution ◽  
Electrolytic Preparation ◽  
The Given

The current yield of the electrolytic preparation of concentrated solutions of ammonium peroxodisulphate was found to decrease with decreasing degree of saturation of the starting solution. It is therefore preferable to work with a starting solution of maximum allowable concentration with respect to the given temperature of electrolysis. As the temperature is increased, the current yield decreases progressively even if starting solution of maximum allowable concentration has been used; at the same time, the voltage on the electrolytic cell somewhat decreases. The observed effect of temperature on the current yield is a resultant of its effects on a number of simultaneously occurring electrochemical and chemical processes in the anode compartment.

scholarly journals A theory relating the action of salts on bacterial respiration to their influence on the solubility of proteins

1947 ◽  
Vol 134 (875) ◽  
pp. 181-201 ◽  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Dehydrogenase Activity ◽  
Halophilic Bacteria ◽  
Convincing Evidence ◽  
Effect Of Temperature ◽  
Bacterial Respiration ◽  
Concentrated Solutions ◽  
Salting Out ◽  
Intact Cells

Evidence has been presented indicating that the action of concentrated solutions of salts on bacterial respiration may be partly explained in terms of salting-out. It has been suggested that the material upon which this action is exerted is probably one of the proteins concerned in respiration, perhaps a dehydrogenating enzyme. This theory provides satisfactory explanations for: ( a ) the relation between salt con­centration and rate of respiration or dehydrogenase activity; ( b ) the effect of temperature on this relation; and ( c ) the effect of pH on this relation, if it is further supposed that only the zwitterionic fraction of the protein is involved. The relative actions of various salts are in fair agreement with this suggestion, but provide no very convincing evidence either for or against it. The chief point of difficulty lies in the range of concentration over which the action is manifest. With halophilic bacteria, the evidence is consonant with the above view if the protein involved is one of high molecular weight. With normal organisms the salt concentra­tions are much lower than those causing salting-out. There is a little evidence that in normal organisms the dehydrogenating enzymes are less sensitive to salts than the intact cells, which may be the source of the discrepancy. No reason for this can yet be suggested, but the property must be absent from the enzymes of halophilic organisms, and whatever it is, its absence must be the foundation of the halophilic character.

scholarly journals Studies in the geotropism of the pteridophyta V—Some effects of temperature on growth and geotropism in Asplenium bulbiferium

1935 ◽  
Vol 116 (800) ◽  
pp. 479-493 ◽  
Keyword(s):  
Growth Rate ◽  
Effect Of Temperature ◽  
Horizontal Position ◽  
Present Position ◽  
Minimum Period ◽  
Plant Life ◽  
Latent Time ◽  
Presentation Time ◽  
Effects Of Temperature ◽  
The Given

Although temperature and gravity both influence plant life, and although both factors have been studied for many decades, there is surprisingly little literature decades, there is surprisingly little literature dealing with the relation between the two; and none, so far as I can discover, on the effect in any Pteridophyte. Navez (1929) who criticized the work of some investigators on the effect of temperature on the geotropism of a few seedlings, sums up the present position in his remark that the conclusions of workers are very different and often in opposition. The present paper gives the results of 1100 experiments carried out mainly between the years 1922 and 1927, and though it is realized that much remains to be done on the question, it is believed that the results which have been obtained are of some value. For general methods, reference may be made to previous “Studies” in this series. Geotropic sensitivity, as measured by presentation time at different stages in development of the frond, was fully worked out by Waight (1923) for 20°C, and is adopted here as a standard of reference. The growth rate recorded in the tables is that for the particular frond under investigation, or is the average of the fronds examined during the day of the experiment. Nearly all the experiments included in the tables were conducted during the months of April-October, as I have since been able to show that there is an annual rhythm in geotropic irritability. A decrease in sensitivity occurs in winter, and hence experiments performed in November-March are not strictly comparable with those carried out in the summer. The following abbreviations are used:- P.S. = period of stimulation. P.T. = presentation time, i. e ., the minimum period of stimulation in a horizontal position, which, under the given conditions, will cause a movement of approximately 5° in about 80% of the fronds. L.T. = latent time (Prankerd, 1925) in hours. N = “normal time,” i. e ., the P.T. For different stages of the frond at 20°C (see Waight, 1923).

scholarly journals Propane Pre-Reforming into Methane-Rich Gas over Ni Catalyst: Experiment and Kinetics Elucidation via Genetic Algorithm

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3393 ◽  
Author(s):  
Sergey I. Uskov ◽  
Dmitriy I. Potemkin ◽  
Leniza V. Enikeeva ◽  
Pavel V. Snytnikov ◽  
Irek M. Gubaydullin ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Molar Ratio ◽  
Ni Catalyst ◽  
Propane Conversion ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Chromium Catalyst ◽  
Nickel Chromium ◽  
Wide Range ◽  
The Given

Pre-reforming of propane was studied over an industrial nickel-chromium catalyst under pressures of 1 and 5 bar, at a low steam to carbon molar ratio of 1, in the temperature range of 220–380 °C and at flow rates of 4000 and 12,000 h−1. It was shown that propane conversion proceeded more efficiently at low pressure (1 atm) and temperatures above 350 °C. A genetic algorithm was applied to search for kinetic parameters better fitting experimental results in such a wide range of experimental conditions. Power law and Langmuir–Hinshelwood kinetics were considered. It was shown that only Langmuir–Hinshelwood type kinetics correctly described the experimental data and could be used to simulate the process of propane pre-reforming and predict propane conversion under the given reaction conditions. The significance of Langmuir–Hinshelwood kinetics increases under high pressure and temperatures below 350 °C.

Diversity of Weeds and Population Dynamics of Predators and Prey Present in Wheat-Mustard Ecosystem at Paklihawa, Rupandehi, Nepal

2018 ◽  
Vol 35 (1) ◽  
pp. 173-181
Author(s):  
S. Khanal ◽  
S. Adhikari ◽  
A. Bhattarai ◽  
S. Shrestha
Keyword(s):  
Population Dynamics ◽  
Chenopodium Album ◽  
Effect Of Temperature ◽  
Weed Species ◽  
Importance Value Index ◽  
Importance Value ◽  
Mustard Aphid ◽  
Wooden Frame ◽  
Index Value ◽  
The Given

A study was conducted at Institute of Agriculture and Animal Science (IAAS), Paklihawa Rupandehi, agronomy field to study the diversity of weeds and population dynamics of predators and prey in wheat-mustard ecosystem. The study was conducted by quadrate sampling method using the wooden frame by selecting 40 sample spots, and locating its coordinates. Predator, prey, some of the beneficial and harmful insects as well as weed species was recorded in 5 days interval in the study. Relationships between the population of the mustard aphid and wheat aphid, lady bird beetle to maximum and minimum temperature were recorded in order to know the effect of temperature in relation to population density. Number of mustard aphid and its nymph has shown the positive significant relationship with the population of the spider in the wheat mustard ecosystem. Shannon Weiner Index value was calculated and the species richness was found to be 2.63 with the effective number of species value 9. The species evenness value was found to be 0.83 in the studied ecosystem which signifies that the given weed ecosystem is somewhat even. The importance value index (IVI) of the given ecosystem with the value of different weed species was calculated and it was found that the weed Anagalis arvensis was ranked as first with the IVI value of 57.98 following Vicia sativa and Chenopodium album. This signifies that the species Anagalis arvensis has greater control over the wheat mustard ecosystem of Paklihawa, Rupandehi.

scholarly journals Analysis of the State of Stress in Cathode Block of an Aluminium Electrolytic Cell During Formation of Connection with the Steel Pin by Cast Iron Pouring

2016 ◽  
Vol 61 (4) ◽  
pp. 1869-1874
Author(s):  
J. Piekło ◽  
M. Maj
Keyword(s):  
Cast Iron ◽  
Numerical Model ◽  
Electrolytic Cell ◽  
The State ◽  
Effect Of Temperature ◽  
Experimental Measurements ◽  
Carbon Block ◽  
Cathode Block ◽  
State Of Stress

Abstract The article presents various aspects of the analysis of the state of stress in carbon block induced by the effect of temperature when a steel pin is connected to the block by pouring a shaped groove with cast iron. Changes in the temperature and state of stress in the block were examined by FEM (Abaqus program). The numerical model was validated by experimental measurements of pin deflection during pouring of the groove with cast iron.

scholarly journals Evaluation of Methods to Correct the Effect of Temperature on Electrical Conductivity of Mortar

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Milena Rangelov ◽  
Somayeh Nassiri
Keyword(s):  
Electrical Conductivity ◽  
Cementitious Materials ◽  
Temperature Correction ◽  
Supplementary Cementitious Materials ◽  
Embedded Sensors ◽  
Degree Of Saturation ◽  
Effect Of Temperature ◽  
Temperature Range ◽  
Durability Assessment ◽  
Higher Temperature

Nondestructive methods to obtain the electrical conductivity (σ) or resistivity (ρ) of concrete are gaining popularity for durability evaluation. However, these methods are susceptible to the effects of curing and conditioning, primarily temperature and degree of saturation. Before σ of concrete at varied temperatures can be used for durability assessment, appropriate corrections must be made to account for the effect of temperature (T). In this study, two existing and one new temperature correction methods were evaluated for 12 mortar mixtures varying in water-to-cementitious material ratio (w/cm) and the content and types of supplementary cementitious materials (SCM). Mortar specimens instrumented with embedded sensors were cured in sealed conditions for 11–13 months. After this period, the sealed specimens were subjected to stepwise temperature change in 5–50°C range while σ was recorded using the embedded sensors. Linear, bilinear, and Arrhenius temperature correction (LTC, BLTC, and ATC, respectively) were fitted to the obtained σ-T datasets and were evaluated for fitness. LTC provided an acceptable fit to the σ-T data (R2 > 0.81) but was found the most suitable in 5–30°C temperature range. BLTC was defined as a combination of two distinct LTC below and above the reference temperature at 23°C and had a better fit to the data (R2 > 0.96). Lastly, ATC showed the best fit among the tested methods (R2 > 0.98) and was found applicable for the full tested temperature range. Comparison of correction coefficients among the mixtures indicated that increase in w/cm results in less sensitivity of σ to temperature. Mixtures with SCM generally exhibit higher temperature sensitivity compared to the corresponding plain mixture. Since the variations in correction coefficients were not substantial (less 18% variation among 10 of 12 mixtures), a single value of activation energy of conduction (Ec) at 32 kJ/mol was identified as the general recommendation for all the tested mixtures.

Degree of saturation with respect to CaCO3, CaMg(CO3)2, and CaSO4 for some thermal and mineral springs in the Southern Rocky Mountains, Alberta and British Columbia

1969 ◽  
Vol 6 (6) ◽  
pp. 1421-1430 ◽  
Author(s):  
R. O. van Everdingen
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Hot Springs ◽  
Equilibrium Constants ◽  
Degree Of Saturation ◽  
Effect Of Temperature ◽  
Mineral Springs ◽  
Southern Rocky Mountains ◽  
Ion Activity ◽  
Ion Activity Products

Comparison of ion-activity products and equilibrium constants for solution of CaCO3, CaMg(CO3)2, and CaSO4 indicates that water from Fairmont Hot Springs and Banff Hot Springs, and from thermal springs in British Columbia, on Lussier River, Ram Creek and near Fording Mountain, are super-saturated with respect to CaCO3 and, to a lesser extent, with respect to CaMg(CO3)2. At other springs saturation occurs after water is discharged from the springs. In the case of hot springs this is caused by the rise in pH that accompanies loss of excess CO2 and, to a lesser degree, by evaporation; cooling of the water tends to lower the degree of saturation somewhat. At cold springs, increase in water temperature after discharge increases the degree of saturation. Only near-saturation with respect to CaSO4 is indicated for Miette Hot Springs, Fairmont Hot Springs, and Fording Mountain Springs; precipitation of CaSO4 may occur here owing to evaporation of part of the water; the effect of temperature on the degree of saturation is small.

Electrochemical Investigation of Under-Deposit Corrosion Behavior for Aluminum Brass in Artificial Seawater

CORROSION ◽  
10.5006/3428 ◽  
2020 ◽  
Vol 76 (11) ◽  
pp. 1050-1063
Author(s):  
Hong Ju ◽  
Weihui Xu ◽  
Jiejing Chen ◽  
Dalei Zhang ◽  
Guomin Liu ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrolytic Cell ◽  
Artificial Seawater ◽  
Localized Corrosion ◽  
Effect Of Temperature ◽  
Multielectrode Arrays ◽  
Energy Dispersive Spectrometry Analysis ◽  
Spectrometry Analysis

The under-deposit corrosion behavior and mechanism of aluminum brass (HAl77-2) were investigated in artificial seawater with a custom double electrolytic cell. The experiments included linear polarization, electrochemical impedance spectroscopy, and multielectrode arrays analysis. The electrochemical results revealed a pronounced effect of temperature on the under-deposit corrosion behavior of HAl77-2. The corrosion of HAl77-2 inside the CaCO3 scale is aggravated with increasing temperature. However, the increasing frequency of the corrosion rate of HAl77-2 gradually decreased after 333 K. Moreover, in the desalination of artificial seawater, the corrosion rate of HAl77-2 in the occulated area initially increased and subsequently decreased with increasing Cl− concentration. The scanning electron microscopy and energy dispersive spectrometry analysis showed a remarkable appearance of selective localized corrosion on the surface of HAl77-2.

Three-component Reaction of Cycloheptanone, 6-Amino-1,3-Dimethyluracil and Aromatic Aldehydes; X-Ray Structure, and Anti-inflammatory Evaluation of the Products

2008 ◽  
Vol 63 (9) ◽  
pp. 1117-1126 ◽  
Author(s):  
Mohamed I. Hegab ◽  
Nasser A. Hassan ◽  
Farouk M. E. Abdel-Megeid
Keyword(s):  
Schiff Bases ◽  
Aromatic Aldehydes ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Reaction Conditions ◽  
X Ray ◽  
Three Component Reaction ◽  
The Given ◽  
First Time ◽  
C Nmr

1,3-Dimethyl-5-aryl-1,6,7,8,9,10-hexahydrocyclohepta[5,6]pyrido[2,3-d]pyrimidine-2,4-diones 4a, b (the linear regioisomers) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5a, b, were isolated from a three-component reaction of cycloheptanone, 6-amino-1,3- dimethyluracil, and 4-chloro- or 4-bromobenzaldehyde. Surprisingly, 1,3-dimethyl-10-aryl-1,5,6,7, 8,9-hexahydrocyclohepta[4,5]pyrido-[2,3-d]pyrimidine-2,4-diones 6f, g (the angular regioisomers which are described for the first time in the literature under the given reaction conditions) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5f, g, were isolated and characterized from the reaction with 4-methoxybenzaldehyde and 4-cyanobenzaldehyde. However, the three-component reaction of 6-amino-1,3-dimethyluracil, cycloheptanone, and 2-methoxybenzaldehyde afforded 1,3-dimethylbenzo[4,5]pyrido[3,2-d]pyrimidine-3,4-dione (7). Single crystal X-ray diffraction and 13C NMR studies of 4a and 6f provided support for the established structures. Some of the new products were tested for antiinflammatory activity comparable to indomethacin.

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