Equivalence of a one-dimensional driven-diffusive system and an equilibrium two-dimensional walk model

It is known that a single product shock measure in some of one-dimensional driven-diffusive systems with nearest-neighbor interactions might evolve in time quite similar to a random walker moving on a one-dimensional lattice with reflecting boundaries. The non-equilibrium steady-state of the system in this case can be written in terms of a linear superposition of such uncorrelated shocks. Equivalently, one can write the steady-state of this system using a matrix-product approach with two-dimensional matrices. In this paper we introduce an equilibrium two-dimensional one-transit walk model and find its partition function using a transfer matrix method. We will show that there is a direct connection between the partition functions of these two systems. We will explicitly show that in the steady-state the transfer matrix of the one-transit walk model is related to the matrix representation of the algebra of the driven-diffusive model through a similarity transformation. The physical quantities are also related through the same transformation.Comment: 5 pages, 2 figures, Revte

Use of in vitro gas production technique to evaluate the effects of microwave irradiation on sorghum (Sorghum bicolor) and wheat (Triticum sp.) nutritive values and fermentation characteristics

Effects of microwave irradiation (900 W) for 3, 5 and 7 min on the nutritive value of sorghum and wheat grains were evaluated by in vitro gas production technique. Gas volume was recorded at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h of incubation and kinetics of gas production were estimated using model: GP = A exp {– exp [1 + (be/A) (LAG – t)]}. Cumulative gas production at 24 h was used for estimation of metabolizable energy, net energy for lactation, short chain fatty acids, digestible organic matter and microbial protein. For sorghum grain, microwave irradiation increased cumulative gas production for most times of incubation linearly. Microwave treatments for 5 and 7 min increased the A fraction linearly in both cereal grain, whereas the maximum rate of gas production (b) decreased linearly only in wheat grain. Microwave treatments for 3, 5 and 7 min increased (P<0.05) metabolizable energy, net energy for lactation and short chain fatty acids content of sorghum grain, but not of wheat grain. It was concluded that microwave irradiation changed the gas production parameters resulting changed ruminal fermentation characteristics that can be considered in ration formulation

Numerical modelling of masonry-infilled reinforced concrete frames : model calibration and parametric study

Generally two methods are proposed for analyzing the infilled frames; Micro modelling approach which finite element method is used to take into account local effects in detail and Macro modelling approach which is a very simplified method that takes into account the global behavior of the structure by replacing the infill with diagonal strut. In the present study a numerical analysis is carried out on a one bay one storey reinforced concrete frame with masonry infill under in-plane loading by using finite element modelling through the DIANA software. The numerical model was calibrated based on experimental results and then a parametric study was carried out, taking into account variation of material properties of infill and its height to length ratio. It is concluded that compressive strength and height to length ratio of the masonry infill has dominant role on the in-plane behavior of these types of masonry infilled frames. Increasing the compressive strength of the masonry enhances the lateral strength of the infilled frames while increasing the height to length ratio of the infill panel results in decrease of their lateral strength and initial stiffness.Fundação para a Ciência e a Tecnologia (FCT

A Non-Cooperative Power Control Game for Multi-Carrier CDMA Systems

In this work, a non-cooperative power control game for multi-carrier CDMA systems is proposed. In the proposed game, each user needs to decide how much power to transmit over each carrier to maximize its overall utility. The utility function considered here measures the number of reliable bits transmitted per joule of energy consumed. It is shown that the user's utility is maximized when the user transmits only on the carrier with the best "effective channel". The existence and uniqueness of Nash equilibrium for the proposed game are investigated and the properties of equilibrium are studied. Also, an iterative and distributed algorithm for reaching the equilibrium (if it exists) is presented. It is shown that the proposed approach results in a significant improvement in the total utility achieved at equilibrium compared to the case in which each user maximizes its utility over each carrier independently.Comment: To appear in Proceedings of the 2005 IEEE Wireless Communications and Networking Conference, New Orleans, LA, March 13 - 17, 200

Experimental evaluation of a constructive system for earthquake resisting masonry enclosure walls

University of Minho is a partner of the INSYSME research project (Innovative Systems for earthquake resistant masonry enclosures in RC buildings), funded by the European Commission. The main aims of this project are to study new systems for masonry infill walls, which combine simplicity with low cost, and to propose recommendations and calculation procedures for their design to seismic actions, filling an existing gap in current regulations. At University of Minho a new construction system for masonry enclosures was developed, being composed of a new commercial unit and vertical steel reinforcement placed in ceramic brick frogs, connected to top and bottom beams. In this paper, the experimental work developed at the University of Minho for validation of the solution proposed for masonry infills is presented and discussed. The experimental validation process of the solution for the masonry enclosure walls was based on in-plane and out-of-plane static cyclic tests. The tests were carried in four specimens built at reduced scale (1:1.5). In order to assess the in-plane behaviour, two specimens have been tested. The first test was done, in a specimen with masonry infill, until maximum drift. In the second test, only reinforcement concrete frame was tested, to access the contribution of masonry infill. For out-of-plane direction two specimens were tested one without reinforcement, and other with reinforcement. The out-of-plane test was carried using an airbag system. In this case only positive direction was considered. In-plane and out-of-plane tests were performed under displacement control according to a load pattern defined based on the FEMA 461 recommendations.FCT -Fuel Cell Technologies Program(606229

First Order Phase Transition in a Reaction-Diffusion Model With Open Boundary: The Yang-Lee Theory Approach

A coagulation-decoagulation model is introduced on a chain of length L with open boundary. The model consists of one species of particles which diffuse, coagulate and decoagulate preferentially in the leftward direction. They are also injected and extracted from the left boundary with different rates. We will show that on a specific plane in the space of parameters, the steady state weights can be calculated exactly using a matrix product method. The model exhibits a first-order phase transition between a low-density and a high-density phase. The density profile of the particles in each phase is obtained both analytically and using the Monte Carlo Simulation. The two-point density-density correlation function in each phase has also been calculated. By applying the Yang-Lee theory we can predict the same phase diagram for the model. This model is further evidence for the applicability of the Yang-Lee theory in the non-equilibrium statistical mechanics context.Comment: 10 Pages, 3 Figures, To appear in Journal of Physics A: Mathematical and Genera

Correspondence between Jordan-Einstein frames and Palatini-metric formalisms

We discuss the conformal symmetry between Jordan and Einstein frames considering their relations with the metric and Palatini formalisms for modified gravity. Appropriate conformal transformations are taken into account leading to the evident connection between the gravitational actions in the two mentioned frames and the Hilbert-Einstein action with a cosmological constant. We show that the apparent differences between Palatini and metric formalisms strictly depend on the representation while the number of degrees of freedom is preserved. This means that the dynamical content of both formalism is identical.Comment: 6 pages, to appear in Mod. Phys. Lett.

One-transit paths and steady-state of a non-equilibrium process in a discrete-time update

We have shown that the partition function of the Asymmetric Simple Exclusion Process with open boundaries in a sublattice-parallel updating scheme is equal to that of a two-dimensional one-transit walk model defined on a diagonally rotated square lattice. It has been also shown that the physical quantities defined in these systems are related through a similarity transformation.Comment: 8 pages, 2 figure

Out-of-plane response of masonry infilled RC frames: effect of workmanship and opening

Publicado em "Brick and block masonry: trends, innovations and challenges. ISBN 978-1-138-02999-6Out-of-plane response of typical South European masonry infilled frames was investigated by testing three reduced scale specimens to investigate the effect of workmanship and presence of opening on the out-of-plane behaviour. The tests were performed considering an airbag to apply the uniform out-of-plane loading for each mass of the infill and by imposing pre-defined values of displacements in the out-of-plane direction in the control point taken at mid height and mid length of the masonry infill wall. Quasi-static cyclic testing was performed just in one direction to be able to monitor the propagation of the cracks and performance of the interfaces during out-of-plane loading. It was concluded that the workmanship is an important factor that may change the out-of-plane response of the specimen by changing the initial stiffness and lateral strength of the specimen. Another important contribution of the workmanship is the change of the collapse pattern of the infill by formation of twoway arching mechanism or one way arching mechanism. When the upper boundary condition of the infill in contact with RC frame is filled properly with mortar, two way arching mechanism was observed otherwise one-way horizontal arching mechanism was formed which exhibits lower out-of-plane resistance. The specimen with a central opening exhibits lower deformation capacity with respect to the reference wall but any decrease in its lateral strength was not recorded.FCT (Portuguese Foundation for Science and Technology), within ISISE, project UID/ECI/04029/2013Portuguese Foundation of Science and Technology for the funding of the project RetroInf—Development of innovative solutions for seismic retrofitting of masonry infill walls (PTDC/ECM/122347/2010

Performance of textile reinforced mortar as strengthening solution of masonry infill walls to seismic action

A elevada vulnerabilidade sísmica das paredes de enchimento em alvenaria tem conduzido à necessidade de reforço deste tipo de paredes, utilizando técnicas convencionais ou usando materiais inovadores. Os Fiber reinforced polymers (FRP’s) são utilizados principalmente como materiais inovadores para o reforço de estruturas. Apesar das vantagens associadas ao uso deste tipo de materiais, esta técnica de reforço apresenta algumas desvantagens, como problemas de aderência, mau comportamento à humidade e ao fogo. Uma solução possível para os problemas associados a estes materiais, pode passar pela substituição de agentes ligantes orgânicos para os inorgânicos, tais com argamassas à base de cimento. As interações entre as fibras e a matriz e também as condições de aderência em compósitos cimentícios pode ser melhorado através da utilização de malhas de reforço embebidas na argamassa de reboco, técnica habitualmente designada em língua inglesa por textile reinforced mortar (TRM). Esta técnica é relativamente nova (utilizada desde dos anos 80), tendo sido estudada por vários investigadores em diferentes aplicações. Neste artigo, investiga-se a utilização desta técnica no reforço de paredes de enchimento de alvenaria para ações no plano que simulam a ação sísmica. Foram ensaiados no plano, três provetes à escala reduzida, representativos da construção dos anos 70 em Portugal, um provete de referência, um provete reforçado com uma malha comercial e um provete reforçado com uma malha de reforço desenvolvida para o efeito. Neste caso as malhas de reforço foram desenvolvidas na Universidade do Minho no departamento de engenharia têxtil. A eficácia da técnica desenvolvida foi comparada com soluções comerciais.The high seismic vulnerability of masonry infilled frames have lead to their in-plane and out-of-plane strengthening by means of conventional techniques or by using innovative materials. Fiber reinforced polymers (FRP’s) are mostly used as innovative materials for retrofitting of structures. In spite of many advantages associated with use of FRPs, this retrofitting technique is not problem-free One possible solution to the problems of FRPs could be the replacement of organic binders with inorganic ones such as cement based mortars. Fiber-matrix interactions and also the bond conditions in cementitious composites could be improved if the fibers replaced with textile sheets. This lead to the formation of textile reinforced mortar (TRM) technique. This technique is relatively a new technique (it was started to use in early 1980s) and was studied by few researchers. In this paper, in-plane retrofitting of the infilled frames was investigated by using textile reinforced mortar (TRM) technique. Three half scale specimens which are representative of construction of 1970s in South European countries, were tested in the in-plane direction, a reference specimen, specimen retrofitted by commercial TRM technique and specimen retrofitted with developed TRM technique. In the developed TRM technique the textile meshes were developed and produced in the Textile Department. The effectiveness of the developed technique was compared with commercial solutions