scholarly journals Study of Microwave Heating Effect in the Behaviour of Graphene as Second Phase in Ceramic Composites

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1119 ◽  
Author(s):  
Rut Benavente ◽  
María Dolores Salvador ◽  
Alba Centeno ◽  
Beatriz Alonso ◽  
Amaia Zurutuza ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Microwave Radiation ◽  
Carbon Materials ◽  
Coefficient Of Thermal Expansion ◽  
Ceramic Composites ◽  
Second Phase ◽  
Mechanical Reinforcement ◽  
High Dielectric ◽  
The Right ◽  
New Carbon Materials

The choice of the right material is essential in microwave processing. The carbon materials are good microwave absorbers, which allows them to be transformed by microwave heating into new carbon materials with adapted properties, capable of heating other materials indirectly. In this paper, the microwave heating of graphene as reinforcement of the lithium aluminosilicate (LAS) ceramics has been explored. LAS ceramics have a near-zero coefficient of thermal expansion and exhibit an effective and efficient heating by microwave. Nevertheless, we have found that the graphene did not show any significant response to the microwave radiation and, hence, the interaction as mechanical reinforcement with the LAS material is harmful. The possible benefits of graphene materials to microwave technology are widely known; however, the mechanism involved in the interaction of microwave radiation with ceramic-graphene composites with high dielectric loss factors has not been addressed earlier.

scholarly journals Microwaves and Heterogeneous Catalysis: A Review on Selected Catalytic Processes

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 246 ◽  
Author(s):  
Vincenzo Palma ◽  
Daniela Barba ◽  
Marta Cortese ◽  
Marco Martino ◽  
Simona Renda ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Energy Saving ◽  
Microwave Heating ◽  
Microwave Radiation ◽  
Heterogeneous Catalysts ◽  
Conventional Heating ◽  
Specific Effects ◽  
Natural Choice ◽  
Future Challenges ◽  
Catalyzed Reactions

Since the late 1980s, the scientific community has been attracted to microwave energy as an alternative method of heating, due to the advantages that this technology offers over conventional heating technologies. In fact, differently from these, the microwave heating mechanism is a volumetric process in which heat is generated within the material itself, and, consequently, it can be very rapid and selective. In this way, the microwave-susceptible material can absorb the energy embodied in the microwaves. Application of the microwave heating technique to a chemical process can lead to both a reduction in processing time as well as an increase in the production rate, which is obtained by enhancing the chemical reactions and results in energy saving. The synthesis and sintering of materials by means of microwave radiation has been used for more than 20 years, while, future challenges will be, among others, the development of processes that achieve lower greenhouse gas (e.g., CO2) emissions and discover novel energy-saving catalyzed reactions. A natural choice in such efforts would be the combination of catalysis and microwave radiation. The main aim of this review is to give an overview of microwave applications in the heterogeneous catalysis, including the preparation of catalysts, as well as explore some selected microwave assisted catalytic reactions. The review is divided into three principal topics: (i) introduction to microwave chemistry and microwave materials processing; (ii) description of the loss mechanisms and microwave-specific effects in heterogeneous catalysis; and (iii) applications of microwaves in some selected chemical processes, including the preparation of heterogeneous catalysts.

Review of New Carbon Materials as Catalyst Supports in Direct Alcohol Fuel Cells

2010 ◽  
Vol 31 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Shuihua TANG ◽  
Gongquan SUN ◽  
Jing QI ◽  
Shiguo SUN ◽  
Junsong GUO ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Carbon Materials ◽  
Catalyst Supports ◽  
Direct Alcohol Fuel Cells ◽  
Alcohol Fuel ◽  
New Carbon Materials

Methods of temperature measurement in microwave heating technologies

2021 ◽  
pp. 20-28
Author(s):  
Boris A. Lapshinov
Keyword(s):  
Temperature Measurement ◽  
Microwave Heating ◽  
Microwave Radiation ◽  
Electromagnetic Fields ◽  
Optical Measurement ◽  
Measurement Methods ◽  
Heating Systems ◽  
Measurement Systems ◽  
Processed Material ◽  
Spectral Pyrometry

In industrial technological processes associated with the heating of the processed material by microwave radiation, it is necessary to measure the temperatures of objects. Methods for measuring temperatures in the fields of technology using microwave heating systems are considered. The main possibilities, disadvantages and limitations of the used contact and non-contact (optical) measurement methods are determined. The requirements for temperature measurement systems under conditions of exposure to strong electromagnetic fields are listed. The possibilities of the spectral pyrometry method are especially noted.

Application of Microwave Heating for Adhesive Joining

1999 ◽  
Author(s):  
Erik T. Thostenson ◽  
Tsu-Wei Chou
Keyword(s):  
Microwave Heating ◽  
Composite Structures ◽  
Material Selection ◽  
Adhesive System ◽  
Conventional Heating ◽  
Joint Interface ◽  
Microwave Curing ◽  
Composite Joint ◽  
High Dielectric ◽  
Microwave Techniques

Abstract In conventional joining of composite materials and sandwich structures, reductions in processing time are limited by inefficient heat transfer. In conventional processing the thermal energy must diffuse through the composite layers to heat the joint interface and cure the thermosetting adhesive, and this outside-in process of heating results in excessive processing times and wasted energy. The purpose of the current work is to examine microwave heating as an alternative to conventional heating for joining of composite structures. Through proper material selection, microwaves are able to penetrate the substrate materials and cure the adhesives in-situ. Selective heating with microwaves is achieved by incorporating interlayer materials that have high dielectric loss properties relative to the substrate materials. In this study, a processing window for elevated temperature curing of an epoxy paste adhesive system (HYSOL EA 9359.3) was developed and composite joint systems were manufactured using conventional and microwave techniques and tested in shear. Microwave curing resulted in both enhanced shear strength and less scatter in experimental data.

Microstructure and Properties of Calcium Borosilicate and Borosilicate Glass-Ceramic Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1422-1425 ◽  
Author(s):  
An Guo Lu ◽  
Tai Qiu
Keyword(s):  
Borosilicate Glass ◽  
Glass Ceramic ◽  
Mass Fraction ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Ceramic Composites ◽  
Glass Content ◽  
Microstructure And Properties ◽  
Calcium Borosilicate ◽  
Crystal Phases

Calcium borosilicate (CaO-B2O3-SiO2, CBS) glass based glass-ceramic composites were prepared by introducing borosilicate glass. The effects of borosilicate glass and firing temperature on the microstructure and properties of the glass-ceramic composites were investigated. The results showed that the composites containing 0~40% (in mass fraction, the same below) borosilicate glass can be sintered at 850°C. The dielectric constant (εr) decreases with the increase of borosilicate glass content and can be adjusted in the range of 5.6~6.6. The coefficient of thermal expansion (CTE) increases with the increase of borosilicate glass content. Increasing sintering temperature favors the precipitations of crystal phases, which have lower εr than CBS glass, resulting in the decrease of εr for the composites.

scholarly journals The right to appeal on criminal procedure under international acts and jurisprudence

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
MSc. Vilard Bytyqi
Keyword(s):  
Best Practice ◽  
Second Phase ◽  
Court Decisions ◽  
Criminal Proceedings ◽  
Advanced Level ◽  
The World ◽  
The Right ◽  
Court Of First Instance ◽  
Comparative Description ◽  
Procedural Aspect

The right to appeal, respectively the right on complaint as per our legal vocabulary, constitutes the basic trunk of the second phase of court decisions in a certain procedure, in particular the criminal proceedings.The aim of this paper is to emphasize the main notions of appeal, but also in other aspects through the comparative description it aims to bring more clarity in differences and similarities that exist in between the appeal which is used in our criminal proceedings and the appeal which is used in the criminal proceedings that take place in the supranational courts. It is known that in courts which consist of international elements, the appeal is positioned in a more advanced level, due to the fact that there are grounds of suspicion used over every element that could be used in any national criminal proceedings.Overall, in any place of the world, the appeal has the goal to remedy court decisions brought by the court of first instance, while, in the procedural aspect it has more or less differences depending on the regulations of criminal procedures of that state. Such difference due to the diversity of the legal systems today are also accepted as the universal legal value, since establishment of international tribunals provides the best practice in this field. 

scholarly journals SYNTHESIS OF 3-TERT-BUTYL-9-R-PYRIMIDO[4,5:3,4]PYRAZOLO[5,1-C][1,2,4]TRIAZINE-4(6H),11(10H)- DIONES AT CONDITIONS OF MICROWAVE RADIATION

2018 ◽  
Vol 59 (3) ◽  
pp. 74
Author(s):  
Lyudmila M. Mironovich ◽  
Pavel V. Afanas'yev ◽  
Anna Yu. Podol’nikova
Keyword(s):  
Microwave Heating ◽  
Microwave Radiation ◽  
Reaction Kinetic ◽  
Kinetic Characteristics ◽  
Tert Butyl

3-tert-butyl-9-R-pyrimido[4’,5’:3,4]pyrazolo[5,1-c][1,2,4]triazine-4(6H),11(10H)-diones was synthesized at the conditions of microwave radiation. The reaction kinetic characteristics were obtained under conditions of thermal and microwave heating.

Enterprise 2.0 Management Challenges

2011 ◽  
Vol 3 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Karen P. Patten ◽  
Lynn B. Keane
Keyword(s):  
Business Value ◽  
User Generated Content ◽  
Future Research ◽  
Second Phase ◽  
Chief Information Officers ◽  
Enterprise 2.0 ◽  
Use Of Services ◽  
It Culture ◽  
The Right ◽  
The Way

The nature of the enterprise and the way people work is changing rapidly. The enabling power and competitive advantage of new social and participative technologies will benefit those that recognize the way work is changing. Web 2.0, the ‘second phase’ of the Web, is the foundation of a new and improved Enterprise 2.0. Enterprise 2.0 provides, through a web of interconnected applications, services, and devices, the capabilities for enterprise employees and vendors to be more competitive and productive and for enterprise customers to be more engaged and loyal by accessing the right information from the right people at the right time. This paper describes Enterprise 2.0 management challenges and issues identified by Chief Information Officers, which include the unauthorized use of services and technologies, the integration of a myriad of technologies and capabilities, and the potential compliance and security implications. The authors have proposed a conceptual framework that explores the relationships of three Enterprise 2.0 dimensions – technology, its use, and how resulting user-generated content may lead to business value – with management implications affecting IT culture and policies within the enterprise. This paper provides observations and suggestions for future research.

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