Cellular Concrete Bricks with Recycled Expanded Polystyrene Aggregate

Cellular concrete bricks were obtained by using a lightweight mortar with recycled expanded polystyrene aggregate instead of sandy materials. After determining the block properties (absorption, compressive strength, and tensile stresses), it was found that this brick meets the requirements of the masonry standards used in Mexico. The obtained material is lighter than the commercial ones, which facilitates their rapid elaboration, quality control, and transportation. It is less permeable, which helps prevent moisture formation retaining its strength due to the greater adherence shown with dry polystyrene. It was more flexible, which makes it less vulnerable to cracking walls due to soil displacements. Furthermore, it is economical, because it uses recyclable material and has properties that prevent deterioration increasing its useful life. We recommend the use of the fully dry EP under a dry environment to obtain the best properties of brick

5th IFToMM Symposium on the History of Machines and Mechanisms

This volume includes contributions presented at the Fifth IFToMM Symposium on the History of Machines and Mechanisms, held at Universidad Autonoma de Queretaro, Santiago de Queretaro, QRO, Mexico, in June 2016. It contains work on theories and facts concerning mechanisms and machines from antiquity to current times as viewed in the present day. Topics include modern reviews of past works; people, history, and their works; direct memories of the recent past; historic development theories; the history of the design of machines and mechanisms; developments of mechanical design and automation; the historic development of teaching; the history of schools of engineering and the education of engineers.

Foreground and Background Components in Separable Complex Systems

Complex systems are composed of a large number of individual components. Many of these systems are separable, i.e., they can be split into two coupled subsystems: one with foreground components and another with background components. The former leads to narrow peaks in the frequency spectrum of the system and the latter gives the broad-band part. There is coupling between the two subsystems, but they can be studied separately for purposes of modeling and for analysis of experimental data. Examples from the literature are given from the area of mechanical vibrations, but the approach is quite general and can be adapted to other kinds of problems