scholarly journals Current Trends in the Development of Microwave Reactors for the Synthesis of Nanomaterials in Laboratories and Industries: A Review

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 379 ◽  
Author(s):  
Sylwia Dąbrowska ◽  
Tadeusz Chudoba ◽  
Jacek Wojnarowicz ◽  
Witold Łojkowski
Keyword(s):  
Construction Material ◽  
Microwave Sintering ◽  
Microwave Energy ◽  
Inorganic Materials ◽  
Synthetic Methods ◽  
Microwave Devices ◽  
Maximum Pressure ◽  
Microwave Technology ◽  
Microwave Reactors ◽  
Synthesis Of Nanomaterials

Microwave energy has been in use for many applications for more than 50 years, from communication, food processing, and wood drying to chemical reactions and medical therapy. The areas, where microwave technology is applied, include drying, calcination, decomposition, powder synthesis, sintering, and chemical process control. Before the year 2000, microwaves were used to produce ceramics, semiconductors, polymers, and inorganic materials; in next years, some new attempts were made as well. Nowadays, it has been found that microwave sintering can also be applied to sintered powder and ceramics and is more effective than conventional sintering. Particularly interesting is its use for the synthesis of nanomaterials. This review identifies the main sources of microwave generation, the delivery mechanisms of microwave energy, and the typical designs and configurations of microwave devices, as well as the measurement and construction material problems related to microwave technology. We focus our attention on the configurations, materials, optimized geometries, and solvents used for microwave devices, providing examples of products, especially nanoparticles and other nanomaterials. The identified microwave devices are divided into four groups, depending on the scale, the maximum pressure developed, the highest temperature for sintering, or other special multi-functions. The challenges of using microwave energy for the synthesis of nanopowders have been identified as well. The desirable characteristics of microwave reactors in the synthesis of nanostructures, as well as their superiority over conventional synthetic methods, have been presented. We have also provided a review of the commercial and self-designed microwave reactors, digestors, and sintering furnaces for technology for synthesis of nanomaterials and other industries.

scholarly journals Microwave Mechanisms — The Energy/Heat Dichoto

2004 ◽  
Vol 12 (2) ◽  
pp. 18-23 ◽  
Author(s):  
Jose J. Galvez ◽  
Richard T. Giberson ◽  
Robert D. Cardiff
Keyword(s):  
Biological Sciences ◽  
Microwave Energy ◽  
Microwave Oven ◽  
Chemical Processes ◽  
Antigen Retrieval ◽  
Microwave Technology ◽  
Plastic Embedding ◽  
Speed Up ◽  
Histological Staining

The current use of microwave technology in science creates a dichotomy. Is it the heat or is it the energy? One entire branch of science, chemistry, uses microwave energy to apply heat to a broad range of chemical processes, under pressure, to produce the desired end-products quickly and efficiently (1). The biological sciences, surgical pathology in particular, have tried to adapt the microwave oven to speed up a broad range of processes: fixation, decalcification, antigen retrieval, tissue processing for paraffin and plastic embedding, and histological staining, including special stains, immunolabeling, and in situ hybridization (2). The biologists have assumed that they are also applying heat to speed processing. However, recent improvements in the microwave suggest that the energy is the critical variable (9). We have designed fixation experiments to test the two views.

Mechanical Properties of La2O3-Al2O3 Ceramics Prepared by Microwave Sintering

2012 ◽  
Vol 519 ◽  
pp. 265-268 ◽  
Author(s):  
Yun Long Ai ◽  
Fei He ◽  
Bing Liang Liang ◽  
Wen He ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Draw Ratio ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Energy ◽  
Pure Alumina ◽  
Sintering Time ◽  
Microstructure Evaluation ◽  
Columnar Grains

The influence of La2O3 on the phase and microstructure evaluation and mechanical properties of La2O3-Al2O3 ceramics sintered with 2.45 GHz microwave energy was investigated. The results showed that La2O3 could densify the pure alumina with a lower sintering temperature and a short sintering time. La2O3 reacted with Al2O3 to form LaAl11O18 completely and the amount of LaAl11O18 increased with the increasing content of La2O3, distributing at the Al2O3 grain boundaries. The specimen doped with 10 vol.% and 15 vol.% La2O3 sintered at 1500 °C exhibited plenty of columnar grains with draw ratio about 1:4. The existence of columnar grains enhanced the microhardness and fracture toughness of La2O3-Al2O3 ceramics.

scholarly journals Recent Developments in the Synthesis and Applications of Metal Organic Framework: A Concise Review

2021 ◽  
Vol 33 (5) ◽  
pp. 956-962
Author(s):  
Chandan Adhikari ◽  
Rehana Farooq
Keyword(s):  
Drug Delivery ◽  
Porous Materials ◽  
Electrochemical Sensors ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Inorganic Materials ◽  
Synthetic Methods ◽  
Concise Review ◽  
Metal Organic ◽  
Organic Framework

Metal organic frameworks (MOFs) are one of those compounds which have drawn attention in various applications due to their several interesting properties like tunable shape, size, pore size, easy functionalization, high surface area, pore volume, etc. Metal organic frameworks due to their uniform structures, tunable porosity, wide variety and stability on various topology, geometry, dimension and chemical functions of the molecular network give a remarkable structural diversity in comparison to other porous materials. This enables scientists to handle numerous framework structures, porosity and functionality effectively. The unique structural architecture and tunable properties of MOF’s makes them an interesting hybrid material consisting of organic and inorganic materials. MOF can be randomly constructed like Lego bricks and superior in terms of versatility in comparisson to other porous materials. A number of MOFs containing a wide variety of metal e.g. zinc, copper, iron, aluminium, magnesium, chromium, zirconium, gadolinium, manganese are gaining rapid growth in commercial markets for gas storage, adsorption, separation and catalytic applications. This concise review emphasizes various synthetic methods e.g. solvothermal process, hydrothermal synthesis, electrochemical synthesis, microwave synthesis, sonochemical synthesis, mechanochemical synthesis, of metal organic framework developed in the last few decades. It also addresses various applications of metal organic framework e.g. hydrogen storage, gas adsorption, drug delivery systems and bioimaging agents, biocatalysts, biosensors, electrochemical sensors, etc. It also comments on various challenges and futuristic applications of metal organic frameworks in various field e.g. liquid wate management, gaseous waste management, sunlight assisted catalysis, water purification, building materials, electronic devices, battery technologies, targeted drug delivery, solar cells, etc. of science and technology in coming decades.

Preparation of diamond/aluminum composite with titanium coating on diamond powder by microwave technology

2021 ◽  
Vol 11 (12) ◽  
pp. 2015-2023
Author(s):  
Zhaohui Han ◽  
Yang Xu ◽  
Lei Xu ◽  
Shenghui Guo
Keyword(s):  
Relative Density ◽  
Microwave Sintering ◽  
Diamond Powder ◽  
Raw Material ◽  
Titanium Coating ◽  
Microwave Technology ◽  
Aluminum Composite ◽  
High Relative Density ◽  
Diamond Particles ◽  
Metallic Bond

In this research, the diamond particles were coated with titanium by microwave heating method, then the Ti-coated diamond particles were used as raw material to fabricate the diamond/Al composites by microwave sintering. The result shows that the diamond particles could be covered with a uniform and continuous Ti coating under microwave irradiation, and the best Ti coating was obtained at 810 °C for 1 h. The metallic bond between diamond and Ti was formed to generate the intermediate transition layer of TiC. The diamond/Al composites which used Ti-coated diamond particles as raw material and were fabricated by microwave sintering show high relative density and hardness. The relative density and hardness of the diamond/Al composites increased with the temperature. While the composites were sintered at 710 °C for 1 h, the density could reach 2.855 g·cm−3, and relative density was 92.09%, which shows better microstructures and properties. There is Al3Ti alloy phase in Ti-coated diamond/Al composites, so the Ti-coated diamond can be well combined with the Al matrix, which can further improve the properties of the composites.

Study on the Frequency Bands Applied in Grains' Moisture Measurement

2013 ◽  
Vol 421 ◽  
pp. 438-443 ◽  
Author(s):  
Hong Wei Wang ◽  
Qi Jun Li ◽  
Zhan Hou Wang
Keyword(s):  
Frequency Band ◽  
Theoretical Foundation ◽  
Microwave Devices ◽  
Microwave Technology ◽  
Current Application ◽  
Frequency Bands ◽  
Moisture Measurement ◽  
Measurement Systems ◽  
Detection Depth ◽  
Working Frequency

As a research hotspot, microwave technology is employed to measure grains moisture. Microwave devices based on various frequency bands appear in some measurement systems. These applications have no a theoretical foundation. This paper provides the principle of microwave technology used in moisture measurement. The factors, detection depth, horizontal and vertical resolutions, which are crucial to select the working frequency, are expounded. This paper also sets forth current application frequencies in moisture measurement systems. At the end, an advisable experiment framework is built to help select the frequency band preliminary for the moisture measurement.

scholarly journals Temperature Distribution in Microwave Sintering of Alumina Cylinders

1994 ◽  
Vol 347 ◽  
Author(s):  
J. R. Thomas ◽  
Joel D. Katz ◽  
Rodger D. Blake
Keyword(s):  
Temperature Distribution ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Heat Transfer Process ◽  
Microwave Energy ◽  
Heating Process ◽  
Temperature Dependent ◽  
Fiber Sensors ◽  
Temperature Dependent Properties ◽  
Multi Mode

ABSTRACTSmall cylinders of high-purity alumina were encased in a “casket” of low-density zir-conia insulation and heated to sintering temperature in a large multi-mode microwave oven. Optical fiber sensors were used to monitor the temperature at several locations in the system. It was found that the alumina samples heat faster than the zirconia insulation at temperatures above 1000°C, and that the temperature distribution in the sample is essentially uniform during the heating process.A two-dimensional mathematical model of the heat transfer process was developed which reproduces the essential features of the observed phenomena. Literature data for all temperature-dependent properties were incorporated into the model. The model suggests that the alumina samples absorb a significant fraction of the microwave energy.

scholarly journals Open source ELMER software based FEM modeling of waveguides and resonant cavities for microwave heating and drying devices

2017 ◽  
Vol 66 (4) ◽  
pp. 745-750 ◽  
Author(s):  
Jakub Szałatkiewicz ◽  
Roman Szewczyk ◽  
Mateusz Kalinowski ◽  
Juhani Kataja ◽  
Peter Råback ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Open Source ◽  
Small And Medium Enterprises ◽  
Microwave Energy ◽  
High Tech ◽  
Test Cases ◽  
Microwave Technology ◽  
Fem Modeling ◽  
Resonant Cavities ◽  
Medium Enterprises

Abstract Microwave devices are widely used in the industry and in the specialized laboratory analyses. Development of such devices requires the possibility of modeling of microwave energy distribution in the specific resonant chambers. Until now, such modeling was possible only with the use of commercial software or was limited to specific cases. The paper presents an open-source module for ELMER software for solving timeharmonic Maxwell’s equations, allowing modeling of microwave waveguide lines. Three test cases of different resonant chambers are investigated at 2.45 GHz frequency. Modeling results obtained from the open-source ELMER Vectorial Helmholtz module show that the application of this software can be effective in R&D works, enabling high-tech small and medium enterprises involvement in advanced microwave technology.

Application of Ridged Waveguide in Microwave Sintering

1996 ◽  
Vol 430 ◽  
Author(s):  
Zhou Jian ◽  
Cheng Jiping ◽  
Liu Xianjun ◽  
Tang Yuling ◽  
Chen Lei
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Rectangular Waveguide ◽  
Electric Field Intensity ◽  
Microwave Sintering ◽  
Cutoff Frequency ◽  
Microwave Energy ◽  
Ceramic Samples ◽  
Ridged Waveguide

AbstractIn this paper, a ridge rectangular waveguide is designed, and its cutoff frequency, impedance and electric field intensity are given by formulas or curves. A few ceramic samples are sintered in it by microwave energy. It is concluded that the device can be as a satisfactory microwave sintering cavity.

Biosynthesis of Silver Nanoparticles

2003 ◽  
Vol 774 ◽  
Author(s):  
Rajesh R. Naik ◽  
Sarah J. Stringer ◽  
Jay M. Johnson ◽  
Morley O. Stone
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Nucleation And Growth ◽  
Inorganic Nanoparticles ◽  
Inorganic Materials ◽  
Synthetic Methods ◽  
Metallic Silver ◽  
Transmission Electron ◽  
Binding Peptides

AbstractThe use of biomolecules in the creation of inorganic materials offers an alternative to conventional synthetic methods. Biomolecules are currently used to control nucleation and growth of inorganic nanoparticles. Here we demonstrate the formation of silver nanoparticles in the presence of silver-binding peptides. Examination of the silver nanoparticles by transmission electron microscopy revealed a variety of crystal morphologies such as hexagons, triangles and spheres. The peptides serve to reduce the silver ions in the aqueous solution to metallic silver as well as control crystal growth. The nucleation property of peptides can be used as tool for bottom-up fabrication.

Sign in / Sign up

Export Citation Format

Share Document