Direct conversion of aryl halides to phenols using high-temperature or near-critical water and microwave heating

AbstractWith the concern of the environment, green dry cutting technology is getting more and more attention and self-lubricating tool technology plays an important role in dry cutting. Due to the demand for high temperature performance of tools during dry cutting process, cemented carbide with Ni3Al as the binder phase has received extensive attention due to its excellent high temperature strength and high temperature oxidation resistance. In this paper, WC-TiC-Ni3Al-CaF2 graded self-lubricating material and tools were prepared by microwave heating method, and its microstructure, mechanical properties and cutting performance were studied. Results show that gradient self-lubricating material can be quickly prepared by microwave heating technology, and the strength is equivalent to that of conventional heating technology. CaF2 not only plays a role in self-lubrication, but also refines the grain of the material. A reasonable gradient design can improve the mechanical properties of the material. When the gradient distribution exponent is n1 = 2, the material has high mechanical properties. Cutting experiments show that the WC-TiC-Ni3Al-CaF2 functional gradient self-lubricating tool has better cutting performance than the homogeneous WC-TiC-Ni3Al hard alloys.

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Microwave Equipment Considerations for High Temperature Studies in Ceramics

MRS Proceedings ◽

10.1557/proc-124-373 ◽

1988 ◽

Vol 124 ◽

Author(s):

Martin Yonnone

Keyword(s):

High Temperature ◽

Microwave Heating ◽

Microwave Field ◽

Rapid Heating ◽

Ceramic Materials ◽

Microwave Energy ◽

Ceramic Samples ◽

Scientists And Engineers

The utilization of microwave energy as a source for the heating of ceramic materials is not a recent discovery. Notably, Von Hippel(1) and others including Tinga(2) investigated the microwave heating of ceramic materials in the 50's and 60's. Today, many microwave scientists and engineers are working on the complexities associated with the rapid heating exhibited by ceramic samples in the microwave field.

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Cutting Performances of Nano-Polycrystalline Diamond

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.523-524.105 ◽

2012 ◽

Vol 523-524 ◽

pp. 105-108

Author(s):

Katsuko Harano ◽

Hitoshi Sumiya ◽

Daisuke Murakami

Keyword(s):

High Temperature ◽

Single Crystal ◽

Cutting Tools ◽

Polycrystalline Diamond ◽

High Hardness ◽

Direct Conversion ◽

High Wear Resistance ◽

Single Crystal Diamond ◽

Anisotropic Mechanical Properties ◽

Hard And Brittle Materials

Single-phase (binder-less) nano-polycrystalline diamond (NPD) has been synthesized by direct conversion sintering from graphite under high pressure and high temperature. NPD is characterized by extremely high hardness compared with single crystal diamond (SCD), even at high temperature. In addition, NPD has high wear resistance, no anisotropic mechanical properties, no cleavages, and high thermal stability. These characteristics suggest that NPD has high potential for use in precision cutting tools for various hard works. In order to evaluate the cutting performance of NPD, cutting tests for various cemented carbides were conducted under various conditions and the results compared with those of single crystal diamond (SCD) and conventional polycrystalline diamond containing metal binder (PCD). The results revealed that NPD has outstanding potential for precision cutting and processing of diverse hard and brittle materials.

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Production of Biofuel Energy by High Temperature Pyrolysis of Sewage Sludge Using Microwave Heating

Journal of Korean Society of Environmental Engineers ◽

10.4491/ksee.2017.39.1.34 ◽

2017 ◽

Vol 39 (1) ◽

pp. 34-39

Author(s):

Byeo Ri Jeong ◽

Young Nam Chun

Keyword(s):

High Temperature ◽

Sewage Sludge ◽

Microwave Heating

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Heat transfer in a novel microwave heating device coupled with atomization feeding

Thermal Science ◽

10.2298/tsci210518288y ◽

2021 ◽

pp. 288-288

Author(s):

Shangzhi Yu ◽

Qinglong Xie ◽

Xiaoning Mao ◽

Ying Duan ◽

Yong Nie

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

High Temperature ◽

Microwave Heating ◽

Flow Rate ◽

Orifice Diameter ◽

Spray Parameters ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Spray Flow Rate

The heat transfer characteristics of the microwave heating coupled with atomization feeding were investigated using ethanol as the spray medium on a pressure swirl nozzle. The effects of spray height, flow rate and temperature on the sauter mean diameter (SMD) of atomized droplets were examined. The results showed that the droplet SMD was 12-130 ?m, which increased with the spray height and decreased with the flow rate and temperature of spray medium. Through the fitting of the experimental data, the dimensionless correlation of the droplet SMD which was based on orifice diameter, Reynolds and Ohnesorge numbers was obtained. The calculated results were basically consistent with the experimental data within 15% error. The heat transfer characteristics of atomized droplets on high-temperature surface of SiC bed heated by microwave were then investigated. The effects of spray flow rate, spray height and spray temperature on the heat transfer characteristics were examined. The power of spray heat transfer decreased with the temperature and increased with the spray flow rate and spray height. The dimensionless correlation to describe the heat transfer characteristics of atomized droplets on the high-temperature SiC surface under the microwave heating was obtained which included thermophysical properties of spray medium, spray parameters, and temperatures of the high-temperature bed surface and spray medium, with the error of ?20%. These correlations can be used to predict the SMD of the atomized droplets and the power of spray heat transfer in the microwave heating process.

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High efficiency extractions of V, Cr, Ti, Fe and Mn from vanadium slag by microwave heating

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb190827023t ◽

2021 ◽

pp. 23-23

Author(s):

B. Tan ◽

S. Wu ◽

L.-J. Wang ◽

K.-C. Chou

Keyword(s):

High Temperature ◽

Reaction Time ◽

Diffusion Process ◽

Microwave Heating ◽

High Efficiency ◽

Conventional Heating ◽

Vanadium Slag ◽

Reduction Processes ◽

Fe And Mn ◽

Speed Up

The vanadium slag (V-slag) is generated from smelting vanadium titanomagnetite ore, which contains valuable elements, such as V, Ti, Cr, Fe and Mn. The traditional methods were mainly focused on the extractions of V and Cr by oxidation or reduction processes. In the present work, chlorination method was adopted to keep the valence state of each elements as original state. In order to speed up the diffusion of elements and reduce volatility of molten salt, microwave heating has been examined in the current paper. The results indicated that it only took 30 min to chlorinate V-slag at 800 ?C, and the chlorination ratios of V, Cr, Mn, Fe and Ti could reach to 82.67%, 75.82%, 92.96%, 91.66% and 63.14%, respectively. Compared with the results by conventional heating for 8 h, this extraction rate by microwave heating shows greater advantages. In addition, microwave heating can reduce effectively volatilization of AlCl3 by shortening the reaction time. The volatilization ratio of AlCl3 in this microwave heating was 3.92% instead of 8.97% in conventional heating (1h). The mechanism of efficient chlorination can be summarized as the enhancement of ions diffusion process and enhanced chemical reaction due to local high temperature.

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