196,122 research outputs found
A Multi-Pier MP method for the non-linear static analysis of out-of-plane loaded masonry walls
No full textThe aim of this paper is to propose a novel 3D truss-like approach called Multi Pier (MP) to analyze the out-of-plane non-linear static behavior of masonry walls. The use of truss elements allows the model to be time-saving, accurate and implementable into a commercial FE software equipped with only non-linearity for 1D elements; consequently, it is characterized by a drastic reduction of the computational effort required and by impressive robustness, being possible an immediate utilization by inexperienced users. In the model, the wall is divided in the horizontal and vertical directions into 3D braced truss frames, with horizontal and vertical elements called piers and diagonal elements called braces. The axial, flexural, and torsional behavior, and their mutual interaction at the meso-scale level (masonry unit cell) are accurately reproduced. Nine experimental masonry walls in two-way bending, in presence or absence of openings and complex boundary conditions, are numerically analyzed to assess the ability of the model at a structural level to reproduce global load–displacement curves obtained experimentally and crack patterns at collapse. A satisfactory match between numerical predictions and experimental evidence is systematically found, meaning that the procedure proposed can represent a simple and valuable tool for all those practitioners not familiar with advanced computations in masonry field, but interested in a reliable prediction of the behavior of masonry walls out-of-plane loaded by means of standard commercial codes
A Multi-Pier MP procedure for the non-linear analysis of in-plane loaded masonry walls
No full textSeveral simplified and advanced methods have been proposed to evaluate the behavior of masonrywalls under in-plane loads, but their implementation in standard commercial software remains still an exception. In this paper, a novel 1D approach called Multi-Pier MP method, which has the advantage that can be used in a commercial software and requires only truss elements with a non-linear softening behavior, is presented. In the model, a masonry structure in-plane loaded is transformed in an assemblage of piers (vertical trusses) and diagonal connecting elements (braces), ensuring by elastic stiffness equivalence that a masonry representative element of volume behaves in the same manner as the 1D system constituted by two vertical trusses and two diagonal braces. After a validation at a unit cell level, where geometric and mechanical properties of the trusses are set in order to reproduce correctly masonry behavior respectively under axial loads, combined shear and compression stresses and bending and shear actions, four masonry full scale shear walls with different length to width ratios and presence or absence of openings are analyzed in the non-linear static range. In addition to experimental results, two Heterogeneous Discrete Element and Finite Element Methods were used with validation purposes. Excellent match among MP Method results, experimental evidences and alternative advanced numerical heterogeneous approaches is found, as far as the prediction of ultimate load, post peak behavior, initial stiffness and failure mechanisms is concerned. The model is also capable to follow at each step of loading the spreading and position of tensile and shear cracks
A Multi-Pier-Macro MPM method for the progressive failure analysis of full scale walls in two way bending
No full textThe aim of the paper is to extend and put at disposal to common users a reliable numerical procedure called MPM (Multi-Pier Macro) approach, already presented in-plane, for walls subjected to two way bending. This approach is developed starting from a Multi-Pier MP approach proposed by the authors in the past. The MP approach for the out-of-plane analysis of masonry can be used for practical purposes, but requires a refined discretization with relatively huge computation effort and a specific training for the user. The MPM approach overcomes some well known limitations of the MP one, using a discretization that is totally independent from the actual unit cell dimension considered and totally unrelated to the specific texture of the masonry wall considered. The MPM method relies on a very unrefined discretization of a wall out-of-plane loaded with parallelepiped cells with large edges made by vertical and horizontal beams plus braces, assuming for each element equivalent geometric and mechanical properties that guarantee the elastic, peak and post peak rough equivalence between the original masonry wall and the mono-dimensional discretization proposed. Its main feature is to allow the analysis of large and complex masonry structures, shortening the calculation time and being accessible to practitioners without a specific background on masonry and who own a commercial software equipped only with non linear 1D elements. The procedure is benchmarked on four walls out-of-plane loaded in two way bending, in presence also of perforations for three of the four walls; a good predictivity in the non-linear range is observed when compared with much more sophisticated numerical approaches
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
Intern experience at CH���M Hill, Inc.: an internship report
No full textIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc.
during the period September 1975 through May 1976 is presented. During this nine month
internship the author worked as an Engineer II in the Industrial Processes discipline of this
large consulting engineering firm... The author's prime responsibility was as one of three
lead design engineers on the design of a large wastewater treatment facility for a pulp mill
in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design
of individual treatment units and associated piping and pumping. The purpose of the project
was to provide wastewater treatment capabilities that would satisfy the effluent limitations
(standards) imposed upon the mill by the State of Washington Department of Ecology and the
U.S. Environmental Protection Agency. The author's assignment also entailed necessary
interaction with the project manager and other CH���M HILL design engineers and support staff
members, the client's representatives, and representatives of two other consulting engineering
firms working on the project. Thus, the internship position at CH���M HILL provided considerable
experience coordinating the author's work with the work of other engineers, guiding the design
and administrative efforts of a support staff, and interacting regularly with the client and
other consulting firms. This broad exposure to a variety of engineering and organizational
problems provided a valuable educational experience
Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15
No full textDirect numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b) broadband free-stream acoustic disturbances, and c) a cold plasma flow control device. While the oblique-mode breakdown is dominant for low-amplitude forcing, long streaky structures drive the transition process in a high-amplitude disturbance environment. LES are also performed on the experimental setup by the Institute of Theoretical and Applied Mechanics (ITAM) from Novosibirsk State University with cold plasma actuation. As well as the disturbance type, the effect of Reynolds number and forcing amplitude will be investigated
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