Application of Romero García method to the degradation process of DGEBA/ETDA filled with ultra fine metallic copper

Summary The thermal properties of an epoxy resin (diglycidyl ether Bisphenol A, DGEBA) cured with a primary amine (ethylenediamine, ETDA) and filled with 10, 20 and 30 wt. % of ultra fine copper particles were analyzed. The thermal results were evaluated by means of the Romero-Garcia method, which allowed to obtain the resin degradation kinetic parameters, as well as the possible decomposition mechanism. From the obtained results is possible to infer that higger copper content strongly affects the degradation process of the epoxy resin, which causes a drop off on the composites thermal stability. This behavior could be attributed to water presence, being this effect less pronounced for the resin with 10 wt. % copper and unfilled resin. Regarding to decomposition mechanism, three way transport showed the best correlation for all samples.     

A comparative study of the durability and behaviour of fat lime and feebly-hydraulic lime mortars

Lime mortars are often used for repairs to historic buildings. This paper investigates two forms of lime binder: fat and feebly-hydraulic, in order to predict their long-term behaviours and hence ascertain which of the two possesses greater durability, so that they may be used more efficiently in restoration. Mortars were tested for properties governing moisture movement and also subject to durability cycles. The resistance to damage under freezing conditions was evaluated with the saturation coefficient. Thermal cycles had no effect on the mortars and gave no indication of the relative durabilities of the binders. Salt crystallization cycles, though effective in distinguishing the more durable of the two, were too aggressive to gauge a clear profile of salt weathering and succeeded in rapidly decomposing the samples. Tests on the properties governing moisture movement produced good indications of the degree to which the mortars permit flow through their fabrics. According to the results obtained, fat lime mortars are more durable than those made with feebly-hydraulic lime. The results also suggest that the feebly-hydraulic lime mortars are at a higher risk of decomposition by granular disintegration whereas fat lime mortars are better suited to damp, slightly exposed conditions. These results disagree with the general opinion that hydraulic limes are more durable than fat limes due to the additional strength and water insolubility arising from their hydraulicity.     

Algorithms for multiprocessor scheduling with two job lengths and allocation restrictions

A variant of the High Multiplicity Multiprocessor Scheduling Problem with C job lengths is considered, in which jobs can be processed only by machines not greater than a given index. When C=2, polynomial algorithms are proposed, for the feasibility version of the problem and for maximizing the number of scheduled jobs.     

Refactoring and converting a TTCN-2 test suite

When deploying TTCN-3 at Nokia, we converted two TTCN-2 test systems to TTCN-3. We explain to which extend we have been able to do the conversion automatically. The conversion tool used provided a syntactically and semantically correct conversion of the TTCN-2 code. We define some improvements made on the tool to increase readability and maintainability of the resulting code. We cover aspects of converting also the non-TTCN-2 parts and describe the experiences we made as a set of lessons learnt.