Testing of Materials and Elements in Civil Engineering

This book was proposed and organized as a means to present recent developments in the field of testing of materials and elements in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of testing of different materials and elements in civil engineering, from building materials to building structures. The current trend in the development of testing of materials and elements in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained

Physical and numerical investigation of conglomeratic rocks

This thesis investigates the mechanics of clast supported conglomerates, through physical and numerical simulations on idealised specimens with spherical clasts and a homogeneous cement matrix. In the physical experiments synthetic conglomerate specimens were prepared from steel spheres as clasts and Portland cement paste as the cement matrix. The mechanical parameters of these specimens were measured in ISRM standard tests. Numerical specimens were prepared in PFC3D using measured and known micro parameters, and tested in conditions as equivalent as possible to the physical experiments. In order to validate the numerical simulations, the responses of the numerical and synthetic conglomerates were compared. Although the numerical tests reproduced many features of the physical tests, some significant differences were observed which were attributed to the presence of cement matrix in the synthetic conglomerate. After a achieving a reasonable calibration between the physical and numerical conglomerates, the simulations were extended to investigate the sensitivity of the cement matrix and the clast properties, effect of specimen size and size distribution of the clasts in controlling the mechanical response of a clast supported conglomerate. The study showed that the mechanical response is sensitive to the strength and stiffness of the cement matrix in uniaxial conditions only. Similarly, clasts’ strength and stiffness was found to significantly influence the mechanical response in triaxial loading but not in uniaxial loading. The specimen size was found to influence the mechanical response of conglomerates, similar to natural rocks. In the clast size distribution study, the peak strength and stiffness of the conglomerate was observed to decrease as the maximum to minimum clast size ratio is increased. A micro mechanical investigation using PFC2D was conducted to explore the clast-cement interaction by modelling the cement matrix as an aggregate of micro particles. It was observed that the properties of the clast-cement interface significantly affect the failure mechanism and peak strength in various modes of deformation. Similarly, the role of the cement matrix was also investigated. It was found that the cement matrix acts as a stress riser and a relation was proposed to estimate the cement induced stress effect, named, the Cement Wedge Effect

Publications of the Jet Propulsion Laboratory July 1965 through July 1966

Bibliography on Jet Propulsion Laboratory technical reports and memorandums, space programs summary, astronautics information, and literature searche

Atmospheric Circulation of Exoplanets

We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric dynamics are given particular attention, as these close-in planets have been the subject of most of the concrete developments in the study of exoplanetary atmospheres. We then turn to the basic elements of circulation on terrestrial planets as inferred from Solar-System studies, including Hadley cells, jet streams, processes that govern the large-scale horizontal temperature contrasts, and climate, and we discuss how these insights may apply to terrestrial exoplanets. Although exoplanets surely possess a greater diversity of circulation regimes than seen on the planets in our Solar System, our guiding philosophy is that the multi-decade study of Solar-System planets reviewed here provides a foundation upon which our understanding of more exotic exoplanetary meteorology must build.Comment: In EXOPLANETS, edited by S. Seager, to be published in the Spring of 2010 in the Space Science Series of the University of Arizona Press (Tucson, AZ) (refereed; accepted for publication

Materials research at Stanford University

Information briefly describing the total research activity related to the science of materials is reported. Emphasis is placed on physical and mechanical properties of composite materials, energy transportation, superconductors, microwave electronics, and solid state electrochemistry