[SCITEPRESS - Science and and Technology Publications 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Vienna, Austria (2014.8.28-2014.8.30)] Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Simplified Closed Form Numerical Approaches to Predict Natural Rubber Behavior under Sulfur Curing in Standard Rheometer Tests