Preliminary Comparison of Microwave Heating of Complex-Shaped Composites Reinforced with Conductive and Nonconductive Fibers

1992 ◽  
Vol 269 ◽  
Author(s):  
Larry A. Fellows ◽  
Susannah Travis ◽  
Martin C. Hawley
Keyword(s):  
Microwave Heating ◽  
Fiber Composite ◽  
Single Frequency ◽  
Mode Switching ◽  
Graphite Fiber ◽  
Uniform Heating ◽  
Electromagnetic Mode ◽  
Complex Shapes ◽  
Microwave Applicator ◽  
Heating Profiles

ABSTRACTThe microwave heating of composites with complex shapes has been studied. A V-shaped mold was used to fabricate samples which do not lie parallel to the electric field produced in a 7-in. cylindrical microwave applicator operating at 2.45 GHz.A polyester/glass composite and a polyester/graphite fiber composite were produced for comparison. Heating profiles were made more uniform by applying mode-switching techniques to the processing. Mode-switching is the application of more than one electromagnetic mode to achieve uniform heating.The samples were tested for heating patterns in different geometric and fiber orientations within a single-frequency, cylindrical microwave applicator operating at 2.45 GHz. The temperature profile for each mode was recorded. Mode-switching provided better temperature profiles than single modes. Modeswitching techniques were more successful with the graphite fiber reinforcement.

Sample movement optimization for uniform heating in microwave heating ovens

2007 ◽  
Vol 17 (2) ◽  
pp. 142-152 ◽  
Author(s):  
J. L. Pedreño-Molina ◽  
J. Monzó-Cabrera ◽  
J. M. Catalá-Civera
Keyword(s):  
Microwave Heating ◽  
Uniform Heating

scholarly journals Finding Pulsar Emission Heights from Dual–Frequency Observations

2000 ◽  
Vol 177 ◽  
pp. 219-220
Author(s):  
Leszek A. Nowakowski
Keyword(s):  
Single Frequency ◽  
Mode Switching ◽  
Dual Frequency ◽  
Radio Pulsars ◽  
Pulsar Emission ◽  
Preliminary Results ◽  
Radio Frequencies ◽  
Radial Separation

AbstractWe present a method that allows to find the radial separation of regions emitting individual components of pulsar average profiles at two radio frequencies. It may also be used for single–frequency observations in pulsars that have intensity–dependent average profiles and/or mode–switching. Preliminary results for three radio pulsars are presented, obtained using average profiles from non-simultaneous observations.

Microwave heating profiles and property-structure relationships in a family of alcohols

1996 ◽  
Vol 15 (19) ◽  
pp. 1730-1732 ◽  
Author(s):  
J. Palacios ◽  
F. D'La Mora ◽  
M. Rubio
Keyword(s):  
Microwave Heating ◽  
Heating Profiles

Die-less Forming of Thermoplastic-Matrix Continuous Fiber Composite Materials—Process and Demonstration

1995 ◽  
Vol 117 (4) ◽  
pp. 501-507 ◽  
Author(s):  
K. Ramani ◽  
A. K. Miller ◽  
M. R. Cutkosky
Keyword(s):  
Composite Materials ◽  
Induction Heating ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Uniform Heating ◽  
Continuous Fiber ◽  
Thermoplastic Matrix ◽  
Bending Behavior ◽  
Fiber Composite Materials ◽  
Heating Profile

Conventionally, large components made of thermoplastic matrices and continuous fibers are manufactured in autoclaves using dies. As the applications of composite materials increase, there is a need to reduce costs and increase manufacturing flexibility. This need has led to the development of a new concept called “die-less forming”. The concept of “kinematically admissible bending” is central to the concept of die-less forming. The concepts behind die-less forming have been tested in preliminary experiments on a two-roller demonstration machine. Induction heating was used to locally heat the composite as it moved into the forming zone, where it was bent using a specially designed cluster roller. Induction heating combined with a variable velocity profile was successful in establishing a uniform heating profile. Experiments were conducted for multidirectional APC-2 carbon/PEEK fiber composites and the composite bending behavior was explained using energy methods.

scholarly journals Evaluation of Microwave Applicator Design on Electromagnetic Field Distribution and Heating Pattern of Cooked Peeled Shrimp

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1903
Author(s):  
Érica S. Siguemoto ◽  
Jorge A. W. Gut ◽  
Georgios Dimitrakis ◽  
Sebastien Curet ◽  
Lionel Boillereaux
Keyword(s):  
Electromagnetic Field ◽  
Temperature Distribution ◽  
Microwave Heating ◽  
Field Distribution ◽  
Heating Process ◽  
Manufacturing Companies ◽  
Electromagnetic Field Distribution ◽  
Shrimp Sample ◽  
Microwave Applicator ◽  
Heating Pattern

Non-uniform temperature distribution within solid food is a major problem associated with microwave heating, which limits industrial applications. Therefore, an experimentally validated 3D model was proposed to study the effect of microwave applicator geometry on the electromagnetic field distribution and heating pattern of shrimp under different processing conditions. Simulation results were compared with physical experiments, in which a cooked peeled shrimp sample was heated using two different laboratory-scale microwave applicators (rectangular and cylindrical cavities). For the rectangular applicator, the temperature distribution within the shrimp, when examined in cross-section, was more homogeneous compared to that of the cylindrical applicator. The results showed the influence of the complex shape of the food on the temperature distribution during microwave heating, as well as of process parameters (input power and geometry cavity). Moreover, this modelling method could provide a better understanding of the microwave heating process and assist manufacturing companies to evaluate a suitable microwave applicator according to their specific purpose.

A Non-Continuum Model of Aligned, Long Fiber Composite Textile Preform Tensile Response

2004 ◽  
Author(s):  
James S. Burns ◽  
Constantin Scheder
Keyword(s):  
Fiber Composite ◽  
Tensile Elongation ◽  
Matrix Material ◽  
Matrix Composites ◽  
Production Methods ◽  
Various Boundary Conditions ◽  
Tensile Response ◽  
Complex Shapes ◽  
Textile Preform ◽  
Fiber Preforms

Stretch-broken fiber preforms provide composites with post-formable characteristics that may reduce the costs of manufacturing complex shapes. Research into fiber preform production methods provides a fiber length and dispersion predictor that is then used to predict forming inputs required to excite tensile elongation of the preform under the influence of various boundary conditions common to sheet-based forming. Fiber behavior is discussed separately from the influence of liquid-phase matrix material. A comparison is made between model results and tensile response measurements of performs for polyarylate-matrix composites.

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