Thermodynamics: processes dynamics under constant heating

2021 ◽  
pp. 123-153
Author(s):  
Jaroslav Sestak
Keyword(s):  
Constant Heating

Characterization of reactive phase formation in sputter-deposited Ni/Al multilayer thin films using TEM

1996 ◽  
Vol 54 ◽  
pp. 1000-1001
Author(s):  
G. Lucadamo ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Dark Field ◽  
Nickel Layer ◽  
Multilayer Thin Films ◽  
Cross Sectional ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Constant Heating

The subject of reactive phase formation in multilayer thin films of varying periodicity has stimulated much research over the past few years. Recent studies have sought to understand the reactions that occur during the annealing of Ni/Al multilayers. Dark field imaging from transmission electron microscopy (TEM) studies in conjunction with in situ x-ray diffraction measurements, and calorimetry experiments (isothermal and constant heating rate), have yielded new insights into the sequence of phases that occur during annealing and the evolution of their microstructure.In this paper we report on reactive phase formation in sputter-deposited lNi:3Al multilayer thin films with a periodicity A (the combined thickness of an aluminum and nickel layer) from 2.5 to 320 nm. A cross-sectional TEM micrograph of an as-deposited film with a periodicity of 10 nm is shown in figure 1. This image shows diffraction contrast from the Ni grains and occasionally from the Al grains in their respective layers.

scholarly journals Entropy generation analysis for MHD flow of water past an accelerated plate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tarek N. Abdelhameed
Keyword(s):  
Magnetic Field ◽  
Entropy Generation ◽  
Transfer Problem ◽  
Finite Difference Methods ◽  
Mhd Flow ◽  
Bejan Number ◽  
Physical Conditions ◽  
Flow Parameters ◽  
The Laplace Transform ◽  
Constant Heating

AbstractThis article examines the entropy generation in the magnetohydrodynamics (MHD) flow of Newtonian fluid (water) under the effect of applied magnetic in the absence of an induced magnetic field. More precisely, the flow of water is considered past an accelerated plate such that the fluid is receiving constant heating from the initial plate. The fluid disturbance away from the plate is negligible, therefore, the domain of flow is considered as semi-infinite. The flow and heat transfer problem is considered in terms of differential equations with physical conditions and then the corresponding equations for entropy generation and Bejan number are developed. The problem is solved for exact solutions using the Laplace transform and finite difference methods. Results are displayed in graphs and tables and discussed for embedded flow parameters. Results showed that the magnetic field has a strong influence on water flow, entropy generation, and Bejan number.

Microstructural development of ZnO using a rate-controlled sintering dilatometer

1996 ◽  
Vol 11 (3) ◽  
pp. 671-679 ◽  
Author(s):  
Gaurav Agarwal ◽  
Robert F. Speyer ◽  
Wesley S. Hackenberger
Keyword(s):  
Thermal Expansion ◽  
Heating Rate ◽  
Grain Growth ◽  
Microstructural Development ◽  
Constant Heating Rate ◽  
Temperature Determination ◽  
Grain Sizes ◽  
Rate Controlled ◽  
Temperature Controlled ◽  
Constant Heating

Rate-controlled sintering (RCS) of isostatically pressed particulate compacts of ZnO showed lower average grain sizes and intragranular pore densities than constant heating rate temperature controlled sintering. Valid comparisons of this form could only be made after corrections to hardware and software which reduced specimen creep under dilatometer pushrod load, nonuniform pushrod expansion, reproducible specimen temperature determination, thermal expansion during sintering, and instantaneous termination of sintering at the specified end of RCS. The improved microstructures from RCS were attributed to maximized efficiency of densification, optimizing the time and temperatures permitted for grain growth.

scholarly journals Rapid Consolidation of WC-ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

2021 ◽  
Author(s):  
Jeong-Han Lee ◽  
Ik-Hyun Oh ◽  
Ju-Hun Kim ◽  
Sung-Kil Hong ◽  
Hyun-Kuk Park
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Lattice Distortion ◽  
Hard Materials ◽  
Plasma Sintering ◽  
Microcrack Propagation ◽  
Spark Plasma ◽  
Crack Tips ◽  
Ductile Component ◽  
Constant Heating

Abstract Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4 was fabricated by spark plasma sintering at 1400 ℃ at a constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried out for 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. It was observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents, and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact was found to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical properties of the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to the presence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zircon from a transgranular to a ductile component (fcc) where the crack tips could be absorbed. Graphic Abstract

Theoretical Thermogravimetric Analysis at Constant Heating Rates

1980 ◽  
pp. 51-56 ◽  
Author(s):  
C. Comel ◽  
J. Veron ◽  
C. Bouster ◽  
P. Vermande
Keyword(s):  
Thermogravimetric Analysis ◽  
Heating Rates ◽  
Constant Heating

Effect of the Two-Steps Sintering in the Microstructure of Ultrafine Alumina

2008 ◽  
Vol 591-593 ◽  
pp. 611-615
Author(s):  
Adriana Scoton Antonio Chinelatto ◽  
Milena K. Manosso ◽  
Elíria Maria Jesus Agnolon Pallone ◽  
Adilson Luiz Chinelatto
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Image Analysis ◽  
Microstructural Analysis ◽  
Analysis Program ◽  
Constant Heating Rate ◽  
Heating Curve ◽  
Final Microstructure ◽  
Constant Heating ◽  
Scanning Electron

The control of the heating curve to manipulate microstructure during sintering is a way that has being studied and it presents advantages such as simplicity and economy. In this work, it was studied the sintering in two-steps of a commercial ultrafine alumina. For this, the alumina power was deagglomerated in milling ball and the specimens for sintering were pressed. Sintering was performed in a dilatometer, with constant heating rate of 15°C/min up to 1500°C. By these results, heat treatment temperatures for two-step sintering were defined. The sintering specimens were characterized through the apparent density measures using Archimedes method, the grain size measures using image analysis program and microstructural analysis using a scanning electron microscope. The results showed that the two-step sintering influence in the development of the final microstructure and permit the control of the grain size and density.

Synthesis and Characterization of Supercapacitor Electrode from Fiber of Borassus flabelifer L by Activation Method

2019 ◽  
Vol 966 ◽  
pp. 444-450 ◽  
Author(s):  
Fandi Angga Prasetya ◽  
Ufafa Anggarini ◽  
Yudha Zakaria ◽  
Rosa Dwi Sasqia Putri
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
High Porosity ◽  
Supercapacitor Electrode ◽  
Nitrogen Gas ◽  
Reduced Graphene ◽  
Higher Temperature ◽  
Constant Heating

Supercapacitor require electrode which has high surface area so that it able to store large amounts of charge. In this study, electrode was synthesized from carbon of Borassus Flabellifer L fiber which was carried out through activation and carbonization processes. Raw material was calcined at 400°C for 4 hours followed by activation with NaOH 1 M. The carbonization was then conducted in Nitrogen gas flowing by temperature variations; 650°C, 750°C, and 850°C with a constant heating rate of 20 °C/min. Based on XRD data, it was shown that the material has formed Reduced graphene Oxide (RGO) which has main peaks at (2θ) 240 and 440 with higher purity in higher temperature. SEM results clarified more pores formation at higher temperature which is mesoporous. Cyclic Voltammetry (CV) test was done to determine the capacitance value. By RGO forming with high porosity, it is suitable for supercapacitor electrode application and CV test has examined that heating of Borassus Flabelifer L fiber at 850°C with 5 mV/s scan rate has the highest specific capacitance by 8.25 F/gram with Energy density is 4.125 watt/gram.

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