Aqueous systems at high temperature. XXI. Apparent invariance of activity coefficients of calcium sulfate at constant ionic strength and temperature in the system calcium sulfate-sodium sulfate-sodium nitrate-water to the critical temperature of water. Association equilibriums

The adsorption of azide ions on mercury electrodes has been studied from constant ionic strength solutions of composition χ M NaN3 + (μ–χ) M NaF with μ = 0.25 and 0.5. Double layer parameters were obtained by taking into account the change in activity coefficients with solution composition. The results were analyzed together with those reported previously for μ = 0.95, recalculated to take into account the change in activity coefficients. The influence of the ionic strength on the amount adsorbed, the properties of the inner layer, and the parameters of an adsorption isotherm for azide anions are discussed in terms of the electrostatic model of the double layer.

Download Full-text

Adsorption of chlorate and bromate ions on mercury electrodes from constant ionic strength solutions

Journal de Chimie Physique ◽

10.1051/jcp/1988850523 ◽

1988 ◽

Vol 85 ◽

pp. 523-527

Author(s):

M.M. Zuleika ◽

Palhares SILVA ◽

Ernesto Rafael GONZALEZ ◽

Luis Alberto AVACA ◽

Artur de Jesus MOTHEO

Keyword(s):

Ionic Strength ◽

Constant Ionic Strength ◽

Mercury Electrodes

Download Full-text

ALLEGHENY STAINLESS TYPE 405

Alloy Digest ◽

10.31399/asm.ad.ss0461 ◽

1985 ◽

Vol 34 (7) ◽

Keyword(s):

Fracture Toughness ◽

Corrosion Resistance ◽

High Temperature ◽

Critical Temperature ◽

Physical Properties ◽

Tensile Properties ◽

Heat Treating ◽

Ductile Material ◽

Air Cooling ◽

Temperature Performance

Abstract ALLEGHENY STAINLESS Type 405, unlike most other 12% chromium steels, is not subject to appreciable hardening through air cooling from high temperatures. This is an advantageous characteristic in those applications where a soft, ductile material is required after rapid cooling from above the critical temperature. The nonhardening tendency of Type 405 also retards the formation of hardening cracks where welding is employed. Its uses include annealing boxes and baffles where hardening during cooling would be undesirable. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating and machining. Filing Code: SS-461. Producer or source: Allegheny Ludlum Corporation.

Download Full-text

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19921451 ◽

1992 ◽

Vol 57 (7) ◽

pp. 1451-1458 ◽

Cited By ~ 6

Author(s):

Refat M. Hassan

Keyword(s):

Ionic Strength ◽

Fractional Order ◽

Activation Parameters ◽

Order Reaction ◽

First Order Reaction ◽

Intermediate Complex ◽

Constant Ionic Strength ◽

Kinetics Of Oxidation ◽

First Order ◽

Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

Download Full-text

Demonstration of Phase Change Thermal Energy Storage in Zinc Oxide Microencapsulated Sodium Nitrate

Applied Sciences ◽

10.3390/app11136234 ◽

2021 ◽

Vol 11 (13) ◽

pp. 6234

Author(s):

Ciprian Neagoe ◽

Ioan Albert Tudor ◽

Cristina Florentina Ciobota ◽

Cristian Bogdanescu ◽

Paul Stanciu ◽

...

Keyword(s):

Zinc Oxide ◽

Thermal Properties ◽

High Temperature ◽

Energy Storage ◽

Phase Change ◽

Thermal Energy ◽

Sodium Nitrate ◽

Thermal Energy Storage ◽

Metal Corrosion ◽

Scanning Calorimetry

Microencapsulation of sodium nitrate (NaNO3) as phase change material for high temperature thermal energy storage aims to reduce costs related to metal corrosion in storage tanks. The goal of this work was to test in a prototype thermal energy storage tank (16.7 L internal volume) the thermal properties of NaNO3 microencapsulated in zinc oxide shells, and estimate the potential of NaNO3–ZnO microcapsules for thermal storage applications. A fast and scalable microencapsulation procedure was developed, a flow calorimetry method was adapted, and a template document created to perform tank thermal transfer simulation by the finite element method (FEM) was set in Microsoft Excel. Differential scanning calorimetry (DSC) and transient plane source (TPS) methods were used to measure, in small samples, the temperature dependency of melting/solidification heat, specific heat, and thermal conductivity of the NaNO3–ZnO microcapsules. Scanning electron microscopy (SEM) and chemical analysis demonstrated the stability of microcapsules over multiple tank charge–discharge cycles. The energy stored as latent heat is available for a temperature interval from 303 to 285 °C, corresponding to onset–offset for NaNO3 solidification. Charge–self-discharge experiments on the pilot tank showed that the amount of thermal energy stored in this interval largely corresponds to the NaNO3 content of the microcapsules; the high temperature energy density of microcapsules is estimated in the range from 145 to 179 MJ/m3. Comparison between real tank experiments and FEM simulations demonstrated that DSC and TPS laboratory measurements on microcapsule thermal properties may reliably be used to design applications for thermal energy storage.

Download Full-text

Evaluation on the Bond Capacity of the Fire-Protected FRP Bonded to Concrete Under High Temperature

International Journal of Concrete Structures and Materials ◽

10.1186/s40069-020-00448-3 ◽

2021 ◽

Vol 15 (1) ◽

Author(s):

Soo-yeon Seo ◽

Jong-wook Lim ◽

Su-hyun Jeong

Keyword(s):

High Temperature ◽

Critical Temperature ◽

Temperature Variation ◽

Fire Resistance ◽

Fire Protection ◽

Element Analysis ◽

External Temperature ◽

Near Surface ◽

Board Type ◽

The Face

AbstractTo figure out the change in the reinforcing effect of FRP system used for the retrofit of RC beam when it is exposed to high temperature, it is required to evaluate not only the behavior of the entire beam, but also the bond performance at anchorage zone through a bond test according to the increase of external temperature. Moreover, the study to find various fire-protection methods is necessary to prevent the epoxy from reaching the critical temperature during an exposure to high temperature. In this manner, the fire-resistance performances of externally bonded (EB) FRP and near-surface-mounted (NSM) FRP to concrete block were evaluated by high-temperature exposure tests after performing a fire-protection on the surface in this paper. Board-type insulation with mortar was considered for the fire-protection of FRP system. After the fire-protection of the FRPs bonded to concrete blocks, an increasing exposure temperature was applied to the specimens with keeping a constant shear bond stress between concrete and the FRP. Based on the result, the temperature when the bond strength of the FRP disappears was evaluated. In addition, a finite element analysis was performed to find a proper method for predicting the temperature variation of the epoxy which is fire-protected with board-type insulation during the increase of external temperature. As a result of the test, despite the same fire-protection, NSM specimens were able to resist 1.54–2.08 times higher temperature than EB specimens. In the design of fire-protection of FRP system with the board-type insulation, it is necessary to consider the transfer from sides as well as the face with FRP. If there is no insulation of FP boards on the sides, the epoxy easily reaches its critical temperature by the heat penetrated to the sides, and increasing the thickness of the FP board alone for the face with FRP does not increase the fire-resistance capacity. As a result of the FE analysis, the temperature variation at epoxy can be predicted using the analytical approach with the proper thermal properties of FP mortar and board.

Download Full-text