Influence of proportion and particle size gradation of rubber from end-of-life tires on mechanical, thermal and acoustic properties of plaster-rubber mortars

This work presents the main experimental results obtained from the study of plaster test pieces and boards with addition of various volumetric rubber fractions from mechanical grinding of end-of-life tires (ELTs), in three different particle size gradations. It includes a description of the materials employed, and their proportions. The physical and mechanical properties, as well as the thermal conductivity and acoustic insulation properties are analyzed. Experimental results obtained for specimens with addition of recycled rubber are compared with similar ones, carried out on specimens of plaster of identical features without any addition, evaluating the influence of the particle size and mixture proportions. An improvement in thermal and acoustic performance has been obtained as well as a reduction in density, and as a result, some constructive applications for paving and slabs in rehabilitation works are proposed.

Recovery of traditional mortars in the laboratory of materials at the school of architectura of Madrid

The Laboratory of Materials seminar is an optional course offered to students in the School of Architecture in Madrid. It is taught during 35 class hours in the laboratory of materials distributed in two hours and forty minutes weekly. One of the working lines is the preparation of traditional mortars made by students groups, each one of 4 or 5 members. It is basically a practical course, and students have to prepare a group of tests pieces in order to confirm the initial hypothesis, or when needed, make innovations. The test pieces are of 150mmx150mmx10mm and applied to big size hollow bricks, prismatic test pieces of 40mmx40mmx160mm to apply physical and mechanical tests and brick wallings of varied dimensions.

On abstraction-carrying code and certificate-size reduction

Abstraction-Carrying Code (ACC) is a framework for mobile code safety in which the code supplier provides a program together with an abstraction (or abstract model of the program) whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certificate and its generation is carried out automatically by a fixed-point analyzer. The advantage of providing a (fixed-point) abstraction to the code consumer is that its validity is checked in a single pass (i.e., one iteration) of an abstract interpretation-based checker. A main challenge to make ACC useful in practice is to reduce the size of certificates as much as possible, while at the same time not increasing checking time. Intuitively, we only include in the certificate the information which the checker is unable to reproduce without iterating. We introduce the notion of reduced certifícate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the full certificate in a single pass. Based on this notion, we show how to instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker.

Certificate size reduction in abstraction-carrying code

Abstraction-Carrying Code (ACC) has recently been proposed as a framework for mobile code safety in which the code supplier provides a program together with an abstraction (or abstract model of the program) whose validity entails compliance with a predefined safety policy. The abstraction plays thus the role of safety certificate and its generation is carried out automatically by a fixpoint analyzer. The advantage of providing a (fixpoint) abstraction to the code consumer is that its validity is checked in a single pass (i.e., one iteration) of an abstract interpretation-based checker. A main challenge to make ACC useful in practice is to reduce the size of certificates as much as possible while at the same time not increasing checking time. The intuitive idea is to only include in the certificate information that the checker is unable to reproduce without iterating. We introduce the notion of reduced certificate which characterizes the subset of the abstraction which a checker needs in order to validate (and re-construct) the fall certificate in a single pass. Based on this notion, we instrument a generic analysis algorithm with the necessary extensions in order to identify the information relevant to the checker. Interestingly, the fact that the reduced certificate omits (parts of) the abstraction has implications in the design of the checker. We provide the sufficient conditions which allow us to ensure that 1) if the checker succeeds in validating the certificate, then the certificate is valid for the program (correctness) and 2) the checker will succeed for any reduced certificate which is valid (completeness). Our approach has been implemented and benchmarked within the CiaoPP system. The experimental results show t h a t our proposal is able to greatly reduce the size of certificates in practice. To appear in Theory and Practice of Logic Programming (TPLP).

EBG size reduction for low permittivity substrates

Double layer and edge-location via techniques are combined for electromagnetic band gap (EBG) size reduction. The study of the required number of elements and their dimensions is carried out in order to suppress the surface wave propagation modes and consequently to reduce the mutual coupling between radiating elements in low-permittivity substrates. By applying these techniques, the size of the EBG mushroom is reduced by 30%; however, the bandwidth operation maintains its value, and these structures can be integrated between radiating elements in broad bandwidth antennas.