552 research outputs found
Sexuality Beyond Consent: Risk, Race, Traumatophilia: A Conversation Among Artemis Christinaki, Amrita Narayanan, and Avgi Saketopoulou
No full textThis transcribed conversation of an online dialogue between Artemis Christinaki, Amrita Narayanan, and Avgi Saketopoulou introduces readers to Saketopoulou’s recently published book, Sexuality Beyond Consent: Risk, Race, Traumatophilia. With astute questions and through a series of probing observations, Christinaki and Narayanan engage the author, opening up crucial dimensions of psychoanalysis, gender and sexuality studies, and politics. The exchange tracks the three main signifiers of the book, risk, race, and traumatophilia, and articulates Saketopoulou’s critical concern with the traumatophobic logics rippling through the field. What emerges is a rich discussion of how Saketopoulou’s three terms work within psychoanalysis and the risks, opportunities, and challenges they unfurl in the clinic and in the broader field of psychosocial and psychoanalytic studies.<br/
Ultra high Performance Concrete - Materials Formulations and Serviceability based Design
No full text[EN] ABSTRACT
Materials and mechanical design procedures for ultra-high performance cement composites
(UHPC) members based on analytical models are addressed. A procedure for the design of
blended components of UHPC is proposed using quaternary cementitious materials. The
blending procedures are used using a packing and rheology optimization approach to blend
high performance mixtures using non-proprietary formulations. Closed-form solutions of
moment-curvature responses of UHPC are derived based on elastic-plastic compressive
model and trilinear strain hardening tension stress strain responses. Tension stiffening
behavior of UHPC due to fiber toughening and distributed cracking is then incorporated in
the cross-sectional analysis. Load-deflection responses for beam members are obtained
using moment-area, and direct integration approach. The proposed models provide insights
in the design of SHCC to utilize the hardening properties after cracking. Using proper
parameters, generalized materials model developed are applicable to both SHCC and strain
softening cement composites such as steel fiber reinforced concrete (SFRC), textile
reinforced concrete (TRC) and ultra-high performance concrete (UHPC)Yao, Y.; Arora, A.; Neithalath, N.; Mobasher, B. (2018). Ultra high Performance Concrete - Materials Formulations and Serviceability based Design. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 1-13. https://doi.org/10.4995/HAC2018.2018.8263OCS11
Introduction
No full textByline: G. Narayanan Author Affiliation: Department of Radiology, University of Miami Miller School of Medicine, Miami, FLAcademi
A New Genetic Algorithm for Continuous Structural Optimization
No full textabstract: In this thesis, the author described a new genetic algorithm based on the idea: the better design could be found at the neighbor of the current best design. The details of the new genetic algorithm are described, including the rebuilding process from Micro-genetic algorithm and the different crossover and mutation formation.
Some popular examples, including two variable function optimization and simple truss models are used to test this algorithm. In these study, the new genetic algorithm is proved able to find the optimized results like other algorithms.
Besides, the author also tried to build one more complex truss model. After tests, the new genetic algorithm can produce a good and reasonable optimized result. Form the results, the rebuilding, crossover and mutation can the jobs as designed.
At last, the author also discussed two possible points to improve this new genetic algorithm: the population size and the algorithm flexibility. The simple result of 2D finite element optimization showed that the effectiveness could be better, with the improvement of these two points.Dissertation/ThesisMasters Thesis Civil and Environmental Engineering 201
Using X-ray fluorescence to assess the chemical composition and resistivity of simulated cementitious pore solutions
No full textIonic transport in concrete can be described using the formation factor, which is the ratio of the resistivity of the concrete and the pore solution resistivity. The pore solution resistivity may be assumed, directly measured, or computed from the pore solution composition. This paper describes an experimental investigation aimed at determining the feasibility of using X-ray fluorescence (XRF) to obtain the alkali concentrations of the pore solution which enable the calculation of pore solution resistivity. In order to do this, simulated pore solutions containing known amounts of sodium and potassium were prepared and analyzed using XRF. XRF was performed on two sample types: (1) the simulated solutions and (2) beads where the water from the solution is evaporated and the remaining material is fused using a fluxing agent. The compositions obtained experimentally from XRF are compared to known compositions to demonstrate the accuracy of the technique. In addition, the measured simulated pore solution resistivity was compared to the simulated pore solution resistivity calculated from XRF measurements. The results indicate that the composition had an average error of 0.50% while the estimated simulated pore solution resistivity had an average error of 10.95%. The results of this study indicate that XRF has the potential to be an alternative to the time consuming methods currently used to measure the composition of the pore solution
Development and characterization of acoustically efficient cementitious materials
No full textTire-pavement interaction noise is one of the significant environmental issues in highly populated urban areas situated near busy highways. The understanding that methodologies to reduce the sound at the source itself is necessary, has led to the development of porous paving materials. This thesis outlines the systematic research effort conducted in order to develop and characterize two different types of sound absorbing cementitious materials—Enhanced Porosity Concrete (EPC), that incorporates porosity in the non-aggregate component of the mixture, and Cellulose-Cement Composites, where cellulose fibers are used as porous inclusions. The basic tenet of this research is that carefully introduced porosity of about 15%–25% in the material structure of concrete will allow sound waves to pass through and dissipate its energy. The physical, mechanical, and acoustic properties of EPC mixtures are discussed in detail. Methods are developed to determine the porosity of EPC. The total pore volume, pore size, and pore connectivity are the significant features that influence the behavior of EPC. Using a shape-specific model, and incorporating the principle of acoustic wave propagation through semi-open cells, the acoustic absorption in EPC has been modeled. The pore structure and performance of EPC is characterized using Electrical Impedance Spectroscopy. Using a multi-phase conducting model, a pore connectivity factor has been developed, that correlates well with the acoustic absorption coefficient. A falling head permeameter has been designed to ascertain the water permeability of EPC mixtures. A hydraulic connectivity factor is proposed, which could be used to classify EPC mixtures based on their permeability. Electrical conductivity is shown to be a single measurable parameter that defines the performance of EPC. Preliminary studies conducted on the freezing and thawing response of EPC are also reported. From several porous, compliant materials, morphologically altered cellulose fibers are chosen to be used as inclusions. The “macronodule” (aggregate-like, 2–8 mm in size) fibers are shown to be the most effective among the various morphologically altered cellulose fibers considered. The physical and mechanical properties (porosity, flexural and compressive strengths, modulus of elasticity), acoustic absorption, and the energy dissipating capacity (specific damping capacity) are evaluated. Composite mixing relations have been used to model the loss modulus and loss tangent of these composites. The response of these composites to extreme exposure conditions has also been studied
Advances in characterization and modeling of cementitious materials: materials and test methods
No full textEvaluating the Use of Accelerated Test Methods for Chloride Transport in Alkali Activated Slag Concretes Using Electrical Impedance and Associated Models
No full textElectrical impedance analysis based quantification of microstructural changes in concretes due to non-steady state chloride migration
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