D-10 Pre-vulcanization of Natural Rubber with Microwave Energy Using a Rectangular Wave Guide(MODE:TE10) : Effect of Sulfur Content(Session: Forming/Vegetable-oil/Rubber)

Author(s):  
Warunee Klinklai ◽  
Noppawan Doo-ngam ◽  
Phadungsak Ratanadecho
1956 ◽  
Vol 52 (3) ◽  
pp. 553-563 ◽  
Author(s):  
V. M. Papadopoulos

ABSTRACTThe scattering of the dominant transverse electric mode in an infinite perfectly conducting rectangular wave-guide by a semi-infinite resistive strip, centrally placed and parallel to the electric field, is calculated by the use of Laplace transforms. Formulae are derived for the amplitude of the scattered waves, and the numerical results, obtained using a digital computer, are given for various values of the surface resistivity of the strip.


2021 ◽  
pp. 009524432110386
Author(s):  
Camila Taliotto Scarton ◽  
Nayrim Brizuela Guerra ◽  
Marcelo Giovanela ◽  
Suélen Moresco ◽  
Janaina da Silva Crespo

In the tire industry, the incorporation of natural origin oils in the development of elastomeric formulations has been one of the alternatives to reduce the use of petroleum derivatives, with a high content of toxic compounds. In this work, soybean vegetable oil was investigated as a lubricant and co-activator in sulfur-vulcanized natural rubber compounds. The soybean oil was used in its natural state and chemically modified by the epoxy ring’s introduction in its structure. In an internal mixer a standard formulation of natural rubber, five formulations replacing a conventional aromatic oil and stearic acid by vegetable oil, and a formulation without an activation system were prepared. The natural and epoxidized soybean oil was characterized chemically, and the elastomeric compositions were evaluated by mechanical and rheological analysis. The mechanical properties showed satisfactory results when vegetable soybean oil was used as a lubricant and could be a substitute for conventional aromatic oils, thus guaranteeing reduction of aromatic polycyclic content in the formulations. The crosslink degree and the rheological characteristics of the samples prepared with vegetable soybean oil were similar to the natural rubber standard sample. The formulations without the zinc oxide and stearic acid evidenced the need for activators in the vulcanization reaction, as they presented properties below standard. We verified that the epoxidized soybean oil, even when promoting better dispersion of the fillers, interfered in the crosslink formation, and consequently there was a decrease in the mechanical properties of these formulations. Finally, we indicated vegetable soybean oil as a substitute for aromatic oil and stearic acid, in the elastomeric compositions used to manufacture treads.


1949 ◽  
Vol 27a (4) ◽  
pp. 69-69 ◽  
Author(s):  
L. Infeld ◽  
J. R. Pounder ◽  
A. F. Stevenson ◽  
W. Z. Chien ◽  
J. L. Synge

Part I deals with the problem of determining the field due to a source of radiation inside a semi-infinite rectangular wave guide closed at one end by a plug, the current distribution in the source being regarded as known. Both the walls of the guide and the plug are treated as being perfectly conducting. Three different methods of solving the problem are given. The radiation resistance is then deduced from energy considerations. In particular, an expression for the radiation resistance of a linear antenna perpendicular to the wider face of the plug, fed at the point of entry, is derived, it being assumed that the antenna current is sinusoidal and that only the fundamental H-wave is transmitted by the guide.In Part II, one of the methods of paper I is extended to the case of a guide of arbitrary cross section, and the general problem of the calculation of radiation resistance and reactance is discussed.In Part III, a number of formulae for the radiation resistance of antennae of various shapes, with various assumed current distributions, in rectangular and circular guides, are given.In Part IV, explicit calculations for the impedance of a linear antenna in a rectangular wave guide are given. Further numerical calculations relating to the same problem, from the point of view of matching and sensitivity, have been made by Messrs. Chien and Pounder, but are not reproduced here.


Sign in / Sign up

Export Citation Format

Share Document