Lattice constant prediction of cubic and monoclinic perovskites using neural networks and support vector regression

In the study of crystalline materials, the lattice constant (LC) of perovskites compounds play important role in the identification of materials. It reveals various interesting properties. In this study, we have employed Support Vector Regression, Artificial Neural Network, and Generalized Regression Neural Network based Computational Intelligent (CI) techniques to predict LC of cubic and monoclinic perovskites. Due to their interesting physiochemical properties, investigations in modeling the structural properties of perovskites have gained considerable attention. A dataset of a reasonable number of cubic and monoclinic perovskites are collected from the current literature. The CI techniques can efficiently correlate the LC of the perovskites materials with the ionic radii of constituent elements. A performance analysis of CI techniques is carried out with Multiple Linear Regression techniques, SPuDS software, and Density-Functional Theory. We have observed that the CI techniques yield accurate LC prediction as against the conventional approaches.Availability: Matlab based computer program developed for this work is available on request.     

Comparison in Undrained Shear Strength between Undisturbed and Remolded Ariake Clays

Triaxial consolidation undrained shear tests are performed on both undisturbed and remolded Ariake clays to investigate the undrained shear strength behavior. When the applied confining stress is larger than the triaxial consolidation yield stress, the strength envelopes expressed in the plot of undrained shear strength versus confining stress of both the undisturbed and the remolded Ariake clays are straight lines through the origin. The strength envelope of the remolded Ariake clays lies above that of the undisturbed Ariake clays when the applied confining stress is larger than the consolidation yield stress. This difference is caused by the difference in water content between undisturbed and remolded states. When the data obtained from triaxial consolidation undrained shear tests of both the undisturbed and the remolded Ariake clays are plotted in the plot of undrained shear strength versus water content, it is found that the undrained shear strength decreases uniquely with the increase in water content.     

Acoustic,thermal and luminous comfort in classrooms

Environmental comfort embodies four different research areas: thermal, luminic, acoustic and ergonomic comfort. However, regarding the built environment, architects and civil engineers should primarily concentrate their efforts on the first three, considering that ergonomic comfort is more related to designers. The purpose of the present paper is to discuss the results of a series of investigations regarding the performance of classrooms, which took place in classrooms of the Federal Center of Technological Education of the State Paraná (Centro Federal de Educação Tecnológica do Paraná—CEFET-PR). Thus, it was possible to cover most of the research area of environmental comfort in an integrated manner.     

Analytical and comparative testing of EnergyPlus using IEA HVAC BESTEST E100–E200 test suite

The EnergyPlus building energy simulation software has been tested using the IEA HVAC BESTEST E100–E200 series of tests. The volume 1 final report for the International Energy Agency (IEA) solar heating and cooling programme task 22 building energy simulation test and diagnostic method for heating, ventilating, and air conditioning equipment models (HVAC BESTEST) was recently published in January 2002. HVAC BESTEST is a series of steady-state tests for a single-zone DX cooling system. Cases range from dry to wet coil, low to high part load, and low to high temperatures. This published test suite includes three sets of analytical solutions and results from several other simulation programs for comparison.This test suite was initially used to test EnergyPlus beginning with beta versions prior to its official public release, and it is also applied as an ongoing quality assurance test. The application of these tests proved to be very useful in several ways:

• •revealed input model shortcomings, which resulted in new user inputs being added;
• •revealed reporting errors which were fixed;
• •revealed algorithmic errors which were fixed;
• •revealed algorithmic shortcomings which were improved or eliminated through the use of more rigorous calculations for certain components;
• •in later versions, caught newly introduced bugs before public release of updates.

Overall, the application of this test suite has been extremely useful in debugging and verifying the DX cooling algorithms in EnergyPlus. This paper summarizes the difficulties encountered and the benefits gained in applying the tests.     

Some significant environmental issues in high-rise residential building design in urban areas

Almost in all the major cities in Asian countries, residential buildings are characterized with high-rise and high density. Under this circumstance, achieving comfortable and healthy indoor environment with minimized energy consumption becomes a very challenging engineering and societal issue. While the wide use of air-conditioning helped to improve thermal comfort, health problems associated with poor indoor air qualities have appeared more frequently. The increased energy consumption is also a great concern in view of its impact on the energy economics of the region. Drawn from some of the onsite measurements and survey, and also the author’s personal observation, some of the key issues are discussed in this paper.     

A general numerical model for grounding analysis in layered soils

Safety of persons, protection of equipment and continuity of power supply are the main objectives of the grounding system of a large electrical installation. For its accurate design, it is essential to determine the potential distribution on the earth surface and the equivalent resistance of the system. In this paper, we present a numerical approach based on the boundary element method for grounding analysis in layered soils. The feasibility of this formulation is discussed by means of its application to a real grounding system with different kinds of layered soil models.     

Out-of-plane behavior of surface-reinforced masonry walls

This paper presents the results of an experimental program designed to evaluate the out-of-plane shear strength of masonry wall system; and to evaluate of the influence of the area of externally bonded FRP composites on the shear strength of the system. Eighteen compact masonry wall panels (3′×2′×8″, 900×600×200 mm) were tested for static out-of-plane loads. Nine panels were reinforced by one layer of WEB ‘S-Glass’ fiber-reinforcing system attached to the tension side of the wall, while the remaining nine were reinforced with two layers of composite overlay on the tension side. The influence of the overlay's embedded length (the distance between the support and the overlay's end) on the shear strength was also investigated. The variables evaluated included three layout configurations and two reinforcement ratios. Three different distances between the overlay end and the adjacent support were tested, 0, d/4 (d is the block unit thickness) and d/2. Both one and two layers of WEB fibers were used and three specimens were evaluated for each variable. An MTS machine was used to test each panel under four-point load conditions. The failure loads, mid-span deflection, fiber-end slippage and failure modes were recorded. Based on the results of the experimental program, it appears that the out-of-plane shear strength of the concrete masonry wall systems is constant over the range of variables tested. The measured shear strength of the masonry wall specimens evaluated in this program indicates that the code defined shear strengths may not be as conservative as assumed.     

Strengthening techniques tested on masonry structures struck by the Umbria–Marche earthquake of 1997–1998

The results of experiments carried out on structures damaged in the Umbria–Marche earthquake of 1997–1998 are presented. These tests were carried out in situ on masonry panels of various dimensions, which had been strengthened with either traditional or innovative materials and techniques. Concerning traditional methods, panels injected with new limed-based mixes were tested. Other tests were realized by gluing to the wallettes sheets of monodirectional carbon fiber (CFRP) or fiber glass (GFRP) with epoxy resins. In both cases the purpose of the tests was to analyze the effectiveness of the intervention, above all as a technique of seismic-upgrading against in-plane mechanisms of collapse. The results show a significant increase in strength. The experiments carried out allowed to obtain interesting indications for their practical utilization of the studied technique. The injection technique is substantially more efficient when used as a method of repair damaged panels, confirming that a preliminary evaluation of dimension and distribution of voids is necessary before adopting this technique. The experimental work showed that the use of composite materials on double-leaf roughly cut stone masonry is more effective when conducted with other stabilization schemes. The failure of the double leaf roughly cut stone panels strengthened with composite materials resulted from the separation of the two masonry leaves. In both cases the strengthening showed remarkable benefits in terms of increase in strength, providing the masonry with greater shear strength. The increase in stiffness following the intervention, as well as its effect, was also analyzed.     

Influence of concrete composition on the characterization of fracture surface

An experimental method based on laser triangulation was used to measure the 3-D profile of fracture surface of concrete. The projective-covering method was established to determine the fractal characteristics of fracture surface. Based on the experiment, the influence of composition of concrete on the fractal dimension, including water–binder ratio, maximum aggregate size and aggregate type, was investigated. The variation of fractal dimension with the material composition was also analysed to make further understanding of fracture mechanism of concrete.     

Solar transparent insulation materials: a review

This paper presents a status report on solar transparent insulation materials (TIM). It covers a survey of the literature, various physical and other properties of TIM devices, their classifications, applications, fabrication procedures, availability and cost trends. The global resurgence of research is clarified. Subsequently, the development of TIM cover systems (often referred to as advanced glazing) from such products as polymer sheets, capillaries and cellular profiles, is discussed. Their design and performance characteristics are investigated; results corresponding to experimental measurements, as well as computational models, are presented. An explicit comparative study of absorber parallel and absorber perpendicular configurations of TIM cover systems is presented. The TIM covers with black end cover plates, and cellular walls of high emissivity, as well as those with selective cover plates and cellular walls fully transparent to IR radiations, have relatively lower heat loss coefficients.