STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART II. THE VISCOSITIES, HEATS OF FUSION, AND HEAT CAPACITIES OF LITHIUM CHLORATE AND LITHIUM CHLORATE–LITHIUM NITRATE MIXTURES

1964 ◽  
Vol 42 (7) ◽  
pp. 1616-1626 ◽  
Author(s):  
A. N. Campbell ◽  
M. K. Nagarajan
Keyword(s):  
Free Energy ◽  
High Precision ◽  
Molten Salts ◽  
Heat Capacities ◽  
Liquid Lithium ◽  
Lithium Nitrate ◽  
Transition Formula ◽  
Different Temperatures ◽  
Molten Lithium ◽  
The Difference

The viscosities at different temperatures of pure molten lithium chlorate and of mixtures of lithium chlorate with lithium nitrate have been determined with high precision. The heats of fusion, and the molar heat capacities of both solid and liquid lithium chlorate, and of mixtures of lithium chlorate and lithium nitrate have also been determined. The heat of the transition [Formula: see text] has been obtained as the difference between the heats of solution in water of the two forms. The enthalpy, free energy, and entropy of mixing have been derived.

STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART I. THE DENSITIES AND MOLAR VOLUMES OF LITHIUM CHLORATE AND OF LITHIUM CHLORATE – LITHIUM NITRATE MIXTURES

1964 ◽  
Vol 42 (5) ◽  
pp. 1137-1144 ◽  
Author(s):  
A. N. Campbell ◽  
M. K. Nagarajan
Keyword(s):  
Molar Volume ◽  
High Precision ◽  
Molten Salts ◽  
Structural Changes ◽  
Lithium Nitrate ◽  
Molar Volumes ◽  
Different Temperatures ◽  
Molten Lithium

The densities at different temperatures of pure molten lithium chlorate and of mixtures of lithium chlorate with lithium nitrate have been determined by a method of high precision. The change of molar volume with temperature has been interpreted in the light of possible structural changes in the melt.

STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART IV. THE ELECTRICAL CONDUCTANCES OF MOLTEN LITHIUM CHLORATE AND OF ITS MIXTURES WITH PROPYL ALCOHOL, LITHIUM NITRATE, WATER, METHYL ALCOHOL, AND LITHIUM HYDROXIDE

1964 ◽  
Vol 42 (8) ◽  
pp. 1984-1995 ◽  
Author(s):  
A. N. Campbell ◽  
D. F. Williams
Keyword(s):  
Activation Energy ◽  
Melting Point ◽  
Methyl Alcohol ◽  
Molten Salts ◽  
Electrical Conductance ◽  
Lithium Hydroxide ◽  
Lithium Nitrate ◽  
Propyl Alcohol ◽  
Electrical Conductances ◽  
Molten Lithium

The electrical conductance and its temperature dependence of molten lithium chlorate have been determined. Similar results have been obtained for lithium chlorate melts containing small quantities of methyl alcohol, propyl alcohol, lithium nitrate, lithium hydroxide, and water.The results obtained, taken in conjunction with the results of previous work, all indicate that the melt is complex. There is probably considerable association and this is especially evident slightly above the melting point: at temperatures in this region the temperature change of the properties of the lithium chlorate melt is greatest.The activation energy of conductance is approximately the same as the activation energy of viscous flow, for pure lithium chlorate melt and for mixtures of lithium chlorate with lithium nitrate. From this it appears that the melt constituents are not principally the simple ions, but that some form of cohesion exists between the simple constituents of the melt.The addition of water to the lithium chlorate melt causes the melt properties to alter considerably, especially the transport properties, viscosity and conductance. It is suggested that these changes may in part be due to a breakup of the structural entities of the pure melt, though the increase in electrical conductance cannot be completely explained in this way. A cryoscopic investigation seems to indicate that water is •not present as such in the melt.

The Determination of Thermal Diffusivities of Thermal Energy Storage Materials: Part II—Molten Salts Beyond the Melting Point

1969 ◽  
Vol 91 (3) ◽  
pp. 189-197 ◽  
Author(s):  
K. Sreenivasan ◽  
M. Altman
Keyword(s):  
Thermal Diffusivity ◽  
Melting Point ◽  
Sodium Nitrate ◽  
Lithium Fluoride ◽  
Molten Salts ◽  
Liquid Lithium ◽  
Energy Storage Materials ◽  
Flux Measurements ◽  
The Difference ◽  
Thermal Diffusivities

A quasisteady method for measuring the thermal diffusivity of molten salts at temperatures above their melting point is described. Essentially, the difference between the temperature at the surface and at the center of a cylindrical container is measured for a constant rate of surface temperature rise. The liquid, whose thermal diffusivity is to be measured, is contained in a narrow annular groove concentric with the surface. The advantages of this method are: (a) no heat flux measurements are needed; (b) no liquid temperature need be measured; (c) theoretically assumed boundary conditions can be experimentally realized; (d) absence of convection can be experimentally verified. Results of measurements are reported for liquid lithium fluoride and sodium nitrate. The results for sodium nitrate agree with previously published results. The thermal conductivity of lithium fluoride can be empirically expressed in terms of the melting point, the molecular weight and the density, as k=0.9Tm1/2ρm2/3M−7/6

scholarly journals Enzymatic Kinetic Issues and Controversies Surrounding Gibbs Free Energy of Activation and Arrhenius Activation Energy

2020 ◽  
pp. 1-13
Author(s):  
Ikechukwu I. Udema ◽  
Abraham Olalere Onigbinde
Keyword(s):  
Activation Energy ◽  
Free Energy ◽  
Equilibrium Constant ◽  
Gibbs Free Energy ◽  
Theoretical Research ◽  
Energy Of Activation ◽  
Arrhenius Activation Energy ◽  
Free Energy Of Activation ◽  
Different Temperatures ◽  
The Difference

Background: The equation of the difference between reverse and forward Gibbs free energy of activation (ΔΔGES#) reflects Michaelis-Menten constant (KM) in both directions; this may not be applicable to all enzymes even if the reverse reaction is speculatively Michaelian. Arrhenius activation energy, Ea and (Ea - ΔGES#)/RT) are considered = ΔGES# and KM respectively. The equations are considered unlikely. Objectives: The objectives of this research are: 1) To derive what is considered as an appropriate equation for the determination of the difference in ΔGES# between the reverse and forward directions, 2) calculate the difference between the reverse and total forward ΔGES#, and 3) show reasons why Ea ≠ ΔGES#  in all cases. Methods: A major theoretical research and experimentation using Bernfeld method. Results and Discussion: A dimensionless equilibrium constant KES is given. Expectedly, the rate constants were higher at higher temperatures and the free energy of activation with salt was < the Arrhenius activation energy, Ea; ΔΔGES#ranges between 67 - 68 kJ/mol. Conclusion: The equations for the calculation of the difference in free energy of activation (ΔΔGES#) between the forward and reverse directions and a dimensionless equilibrium constant for the formation of enzyme-substrate (ES) were derivable. The large positive value of the ΔΔGES# shows that the forward reaction is not substantially spontaneous; this is due perhaps, to the nature of substrate. The equality of Arrhenius activation energy (Ea) and ΔGES# may not be ruled out completely but it must not always be the case; the presence of additive like salt can increase the magnitude of Ea well above the values of the ΔGES#. A dimensionless equilibrium constant for the net yield of ES seems to be a better alternative than KM. The Ea unlike ΔGES#  requires at least two different temperatures for its calculation.

STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART III. DENSITIES, MOLAR VOLUMES, VISCOSITIES, AND SURFACE TENSIONS OF MOLTEN LITHIUM CHLORATE, WITH SMALL ADDITIONS OF WATER, AND OTHER SUBSTANCES

1964 ◽  
Vol 42 (8) ◽  
pp. 1778-1787 ◽  
Author(s):  
A. N. Campbell ◽  
D. F. Williams
Keyword(s):  
Surface Tension ◽  
Melting Point ◽  
Temperature Dependence ◽  
Temperature Change ◽  
Molten Salts ◽  
Surface Heat ◽  
Lithium Nitrate ◽  
Molar Volumes ◽  
Other Substances ◽  
Molten Lithium

The density (2.088 g ce−1) at 131.8 °C and viscosity (0.35 P at 131.8 °C) and their temperature dependence, of molten lithium chlorate, have been determined. Similar results have been obtained for lithium chlorate melts containing small quantities of water. The surface tension and its temperature dependence have been determined for lithium chlorate and for several lithium chlorate – water and lithium chlorate – lithium nitrate mixtures. From these measurements the surface heat has been calculated.The results for pure lithium chlorate indicate that the melt is complex, this complexity probably caused by association of some kind. This is especially evident just above the melting point, since there the temperature change in properties is greatest.Addition of water to the lithium chlorate melt causes the melt properties, especially the viscosity, to alter considerably. These changes are in part caused by a breakdown of the structural entities in the melt.

Synthesis and characterization of a series of 1-methyl-4-[2-aryl-1-diazenyl]piperazines and a series of ethyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates

2004 ◽  
Vol 82 (8) ◽  
pp. 1294-1303 ◽  
Author(s):  
Vanessa Renée Little ◽  
Keith Vaughan
Keyword(s):  
Free Energy ◽  
Chemical Shifts ◽  
Linear Free Energy Relationship ◽  
Piperazine Ring ◽  
Linear Free Energy ◽  
In Series ◽  
Methylene Groups ◽  
Diazonium Coupling ◽  
The Difference

1-Methylpiperazine was coupled with a series of diazonium salts to afford the 1-methyl-4-[2-aryl-1-diazenyl]piperazines (2), a new series of triazenes, which have been characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. Assignment of the chemical shifts to specific protons and carbons in the piperazine ring was facilitated by comparison with the chemical shifts in the model compounds piperazine and 1-methylpiperazine and by a HETCOR experiment with the p-tolyl derivative (2i). A DEPT experiment with 1-methylpiperazine (6) was necessary to distinguish the methyl and methylene groups in 6, and a HETCOR spectrum of 6 enabled the correlation of proton and carbon chemical shifts. Line broadening of the signals from the ring methylene protons is attributed to restricted rotation around the N2-N3 bond of the triazene moiety in 2. The second series of triazenes, the ethyl 4-[2-phenyl-1-diazenyl]-1-piperazinecarboxylates (3), have been prepared by similar diazonium coupling to ethyl 1-piperazinecarboxylate and were similarly characterized. The chemical shifts of the piperazine ring protons are much closer together in series 3 than in series 2, resulting in distortion of the multiplets for these methylenes. It was noticed that the difference between these chemical shifts in 3 exhibited a linear free energy relationship with the Hammett substituent constants for the substituents in the aryl ring. Key words: triazene, piperazine, diazonium coupling, NMR, HETCOR, linear free energy relationship.

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

scholarly journals First in-orbit results of the vector magnetic field measurement of the High Precision Magnetometer onboard the China Seismo-Electromagnetic Satellite

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Bin Zhou ◽  
Bingjun Cheng ◽  
Xiaochen Gou ◽  
Lei Li ◽  
Yiteng Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Precision ◽  
Magnetic Field Measurement ◽  
Vector Data ◽  
Magnetic Field Data ◽  
Night Side ◽  
The Difference ◽  
The Magnetic Field ◽  
Ground Calibration ◽  
Data Calibration

Abstract The High Precision Magnetometer (HPM) is one of the main payloads onboard the China Seismo-Electromagnetic Satellite (CSES). The HPM consists of two Fluxgate Magnetometers (FGM) and the Coupled Dark State Magnetometer (CDSM), and measures the magnetic field from DC to 15 Hz. The FGMs measure the vector components of the magnetic field; while the CDSM detects the magnitude of the magnetic field with higher accuracy, which can be used to calibrate the linear parameters of the FGM. In this paper, brief descriptions of measurement principles and performances of the HPM, ground, and in-orbit calibration results of the FGMs are presented, including the thermal drift and magnetic interferences from the satellite. The HPM in-orbit vector data calibration includes two steps: sensor non-linearity corrections based on on-ground calibration and fluxgate linear parameter calibration based on the CDSM measurements. The calibration results show a reasonably good stability of the linear parameters over time. The difference between the field magnitude calculated from the calibrated FGM components and the magnitude directly measured by the CDSM is just 0.5 nT (1σ) when the linear parameters are fitted separately for the day- and the night-side. Satellite disturbances have been analyzed including soft and hard remanence as well as magnetization of the magnetic torquer, radiation from the Tri-Band Beacon, and interferences from the rotation of the solar wing. A comparison shows consistency between the HPM and SWARM magnetic field data. Observation examples are introduced in the paper, which show that HPM data can be used to survey the global geomagnetic field and monitor the magnetic field disturbances in the ionosphere.

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

Kinetics of Ion-Pair Effect of Aquation of Bromopentaammine Cobalt(III) Complex in Different Dicarboxylate Media

2011 ◽  
Vol 324 ◽  
pp. 166-169 ◽  
Author(s):  
Farah Zeitouni ◽  
Gehan El-Subruiti ◽  
Ghassan Younes ◽  
Mohammad Amira
Keyword(s):  
Free Energy ◽  
Solvent Effect ◽  
Compensation Effect ◽  
Ion Pairing ◽  
Reaction Rates ◽  
Ion Pair ◽  
Free Energy Of Activation ◽  
Different Types ◽  
Different Temperatures ◽  
Kinetics Of

The rate of aquation of bromopentaammine cobalt(III) ion in the presence of different types of dicarboxylate solutions containing tert-butanol (40% V/V) have been measured spectrophotometrically at different temperatures (30-600°C) in the light of the effects of ion-pairing on reaction rates and mechanism. The thermodynamic and extrathermodynamic parameters of activation have been calculated and discussed in terms of solvent effect on the ion-pair aquation reaction. The free energy of activation ∆Gip* is more or less linearly varied among the studied dicarboxylate ion-pairing ligands indicating the presence of compensation effect between ∆Hip* and ∆Sip*. Comparing the kip values with respect of different buffers at 40% of ter-butanol is introduced.

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