The structural performance of monolithic intersecting walls in a tall reinforced concrete building

Results of the seismic performance assessment of a new structural system that has been used in a 54‐story reinforced concrete building are presented. The structure, which is still under construction, and has a ‘Y‐shape’ form, utilizes a special structural system that does not include any beams or columns. Instead, walls and slabs are used for carrying both gravitational and lateral loads. The general distinctions of the system are discussed. The structural efficiency of the system is compared with other conventional systems in some existing tall buildings. The seismic responses and dynamic behavior of the structure that were achieved by conducting various analyses are presented. The effects of analysis method, as well as some other parameters such as modeling assumptions and bidirectional earthquake excitation on the linear responses, are studied. The influence of the number of modes and design spectrum on the spectral analysis results is discussed. Using dynamic analysis, the real heightwise distribution of lateral loads occurring during an earthquake is presented. Copyright © 2007 John Wiley & Sons, Ltd.     

Parametric study of water vapor absorption into a constrained thin film of lithium bromide solution

This study presents a two-dimensional numerical simulation of a membrane-based absorber. A comprehensive parametric study is performed to quantify the influence of different operational and geometrical parameters such as solution film thickness, velocity, and concentration, cooling water temperature, and membrane thickness, pore size, and porosity on the absorption rate. In addition, the effect of membrane surface roughness on the absorption rate is investigated. The results indicate that the most critical parameters that affect the absorption rate are the solution film thickness and velocity. While it is impossible to control these parameters independently in a conventional absorber, they can be readily adjusted in the proposed membrane-based absorber to achieve the optimal performance. The simulation results suggest up to 3-fold enhancement in the absorption rate when a solution film thickness in the range of 50–100 μm is used.     

Radar backscattering model for multilayer mixed-species forests

A multilayer canopy scattering model is developed for mixed-species forests. The multilayer model provides a significantly enhanced representation of actual complex forest structures compared to the conventional canopy-trunk layer models. Multilayer Michigan Microwave Canopy Scattering model (Multi-MIMICS) allows overlapping layer configuration and a tapered trunk model applicable to forests of mixed species and/or mixed growth stages. The model is the first-order solution to a set of radiative transfer equations and includes layer interactions between overlapping layers. It simulates SAR backscattering coefficients based on input dimensional, geometrical, and dielectric variables of forest canopies. The Multi-MIMICS is an efficient realization of actual forest structures and can be shaped for specific interest of forest parameters. We present the model's application and validation in the paper. The model is parameterized using data collected from a 220,000-ha area of forests in central Queensland, Australia. Fifteen 50/spl times/50 m test sites representing the general forest diversity and growth stages are chosen as ground truth. Polarimetric backscattering airborne SAR (AIRSAR) data of the same area are acquired to validate the model simulations. The model predicts SAR backscattering coefficients of the test areas. Simulation results show a good agreement with AIRSAR data at most frequencies and polarizations. The simulated backscattering coefficient from the multilayer model and the standard MIMICS are also compared and significant improvements are observed.     

Investigation of the effect of heat attachment method parameters at photocatalytic activity of immobilized ZnO nanoparticles on glass plate

The effect of heat attachment method parameters such as: sonication time, dosage of catalyst, immobilization temperature and type of solvent were investigated for enhancement of photocatalytic activity of immobilized ZnO nanoparticles on glass plate. Photocatalytic activity of immobilized ZnO was tested in the removal of C.I. Acid Red 88 (AR88) as a model contaminant from textile industry. Results indicated that sonication time, dosage of catalyst and immobilization temperature were very effective on photocatalytic activity of immobilized ZnO on glass plate and using ethanol instead of water at preparation of immobilized ZnO did not show any considerable effect. In another step, the effect of operational parameters such as light intensity and initial concentration of AR88 on the removal of AR88 were investigated with immobilized ZnO on glass plate. Results indicated that removal rate decreased with increasing initial concentration of AR88 but increased with increasing UV light intensity.     

Thin-film optical function acquisition from experimental measurements of the reflectance and transmittance spectra: a case study

Journal of Materials Science: Materials in Electronics - The determination of the spectral dependence of thin-film optical functions from experimental measurements of the optical response,...     

Shape memory response of porous NiTi shape memory alloys fabricated by selective laser melting

Porous NiTi scaffolds display unique bone-like properties including low stiffness and superelastic behavior which makes them promising for biomedical applications. The present article focuses on the techniques to enhance superelasticity of porous NiTi structures. Selective Laser Melting (SLM) method was employed to fabricate the dense and porous (32–58%) NiTi parts. The fabricated samples were subsequently heat-treated (solution annealing?+?aging at 350?°C for 15?min) and their thermo-mechanical properties were determined as functions of temperature and stress. Additionally, the mechanical behaviors of the samples were simulated and compared to the experimental results. It is shown that SLM NiTi with up to 58% porosity can display shape memory effect with full recovery under 100?MPa nominal stress. Dense SLM NiTi could show almost perfect superelasticity with strain recovery of 5.65 after 6% deformation at body temperatures. The strain recoveries were 3.5, 3.6, and 2.7% for samples with porosity levels of 32%, 45%, and 58%, respectively. Furthermore, it was shown that Young’s modulus (i.e., stiffness) of NiTi parts can be tuned by adjusting the porosity levels to match the properties of the bones.

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RSLDI: Restoration of single-sided low-quality document images

This paper addresses the problem of enhancing and restoring single-sided low-quality single-sided document images. Initially, a series of multi-level classifiers is introduced covering several levels, including the regional and content levels. These classifiers can then be integrated into any enhancement or restoration method to generalize or improve them. Based on these multi-level classifiers, we first propose a novel PDE-based method for the restoration of the degradations in single-sided document images. To reduce the local nature of PDE-based methods, we empower our method with two flow fields to play the role of regional classifiers and help in preserving meaningful pixels. Also, the new method further diffuses the background information by using a content classifier, which provides an efficient and accurate restoration of the degraded backgrounds. The performance of the method is tested on both real samples, from the Google Book Search dataset, UNESCO's Memory of the World Programme, and the Juma Al Majid (Dubai) datasets, and synthesized samples provided by our degradation model. The results are promising. The method-independent nature of the classifiers is illustrated by modifying the ICA method to make it applicable to single-sided documents, and also by providing a Bayesian binarization model.     

Development of separated turnstile antenna for space applications

Dual-band operation and circular polarization are the main characteristics of the separated turnstile (ST) antenna that make it suitable for space applications. In this paper, we describe the design and optimization of a separated turnstile antenna to obtain a saddle-shaped pattern in the UHF band and an omnidirectional pattern in the VHF band, with simultaneous impedance matching in both bands. The antenna model and the effects of the body of the satellite and the solar panels were analyzed using the Moment Method. The effects of the physical parameters of the antenna on the radiation pattern, such as the length of the monopoles and their mounting angle, were investigated. A radio-frequency distribution unit - which included a diplexer, phase shifters, and a power divider/combiner for both bands - was also designed, analyzed, and measured. The test results agreed with the analysis results. The axial ratio and polarization efficiency of this antenna were calculated for incident waves with different polarizations. The antenna was fabricated and its radiation parameters were measured. The test results were compared with the analysis results to confirm the correctness of the design.     

Low quality document image modeling and enhancement

In order to tackle problems such as shadow- through and bleed-through, a novel defect model is developed which generates physically damaged document images. This model addresses physical degradation, such as aging and ink seepage. Based on the diffusive nature of the physical defects, the model is designed using virtual diffusion processes. Then, based on this degradation model, a restoration method is proposed and used to fix the bleed-through effect in double-sided document images using the reverse diffusion process. Subjective and objective evaluations are performed on both the degradation model and the restoration method. The experiments show promising results on both real and generated data.