Retrofitting of earthquake-damaged steel buildings

Building owners and government officials around the world in regions with high seismicity have become aware of the potential risk associated with seismically hazardous buildings. Disaster experiences in Iran and throughout the region have urged the development of aseismic engineering for the new construction and upgrading schemes for the existing buildings. Many different construction types exist in the region, but due to the availability of steel sections, most traditional buildings are built using steel construction. This paper will present the upgrade design of a series of five-storey residential steel buildings.     

Wind Damage to Airport: Lessons Learned

High winds at a maximum speed of 96 mph (43 m∕s) hit the Columbia Regional Airport in Missouri on June 17, 1985, causing heavy damage to parked aircraft, hangars, building glass windows, automobiles, and so on. A post‐disaster investigation reveals a wealth of information, such as the finding that the storm was a microburst, and not a tornado as it was originally classified, that the aircraft tiedown system was flawed, that a gravel road was the principal source of damage to cars parked at the airport terminal, that the gust factor of this type of wind is much higher than normally assumed for structural design, and so on. Additional findings are that the atmospheric pressure of the storm measured was greatly affected by the wind‐generated pressure of the building in which the barometer was housed, and that west is the predominant direction of high winds at this airport. Lessons learned from the investigation can be very helpful in reducing future wind damage at airports and in improving understanding of weather data pertaining to severe storms and how to use these data in engineering practice.     

Modelling of spatial causality among distinctive properties of an image using conditional random field for image classification

In this paper, we proposed an ordered patch-based method using conditional random field (CRF) in order to encode local properties and their spatial relationship in the images to address texture classification, face recognition and scene classification problems. Typical image classification approaches classify images without considering spatial causality among distinctive properties of an image to represent it in the feature space. In this method first, each image is encoded as a sequence of ordered patches including local properties. Second, the sequence of these ordered patches is modelled as a probabilistic feature vector using CRF to model spatial relationship of these local properties; and finally, image classification is performed on such probabilistic image representation. Experimental results on several standard image datasets indicate that the proposed method outperforms some of existing image classification methods.     

An Electromagnetism-like algorithm for cell formation and layout problem

Implementation of cellular manufacturing systems (CMS) is thriving among manufacturing companies due to many advantages that are attained by applying this system. In this study CMS formation and layout problems are considered. An Electromagnetism like (EM-like) algorithm is developed to solve the mentioned problems. In addition the required modifications to make EM-like algorithm applicable in these problems are mentioned. A heuristic approach is developed as a local search method to improve the quality of solution of EM-like. Beside in order to examine its performance, it is compared with two other methods. The performance of EM-like algorithm with proposed heuristic and GA are compared and it is demonstrated that implementing EM-like algorithm in this problem can improve the results significantly in comparison with GA. In addition some statistical tests are conducted to find the best performance of EM-like algorithm and GA due to their parameters. The convergence diagrams are plotted for two problems to compare the convergence process of the algorithms. For small size problems the performances of the algorithms are compared with an exact algorithm (Branch & Bound).     

A stochastic optimization model for integrated forward/reverse logistics network design

In this paper, we develop a stochastic programming model for an integrated forward/reverse logistics network design under uncertainty. First, an efficient deterministic mixed integer linear programming model is developed for integrated logistics network design to avoid the sub-optimality caused by the separate design of the forward and reverse networks. Then the stochastic counterpart of the proposed MILP model is developed by using scenario-based stochastic approach. Numerical results show the power of the proposed stochastic model in handling data uncertainty.     

Liquid–liquid extraction of toluene from its mixtures with aliphatic hydrocarbons using an ionic liquid as the solvent

The knowledge of liquid–liquid equilibria (LLE) of the ternary systems (alkane/toluene/ionic liquid) is essential to develop thermodynamic models for liquid–liquid extraction of aromatics such as toluene from its mixtures with aliphatic hydrocarbons. In this study, new experimental LLE data for the ternary systems (hexane and heptane/toluene/1-methyl-3-octylimidazolium tetraflouroborate) are measured at T = 298.15 K and atmospheric pressure. The capability of ionic liquid for extracting toluene from its azeotropic mixture with aliphatic hydrocarbons (hexane and heptane) has been evaluated by the selectivity and solute distribution coefficients. The Othmer–Tobias equation has been applied to check the consistency of the experimental tie-lines. Finally, the obtained experimental LLE data are satisfactorily correlated by the nonrandom two-liquid model.     

Effects of compatibilization of oxidized polypropylene on PP blends of PP/PA6 and PP/talc

The influence of compatibilization on the dynamic mechanical properties of polypropylene (PP) binary blends with polyamide‐6 (PA6), Talc, and oxidized PP (OPP) was investigated. The oxidation of PP homopolymer was performed in a internal mixer by using air as a oxidizing agent (under atmospheric pressure) and dodecanol‐1 as an accelerator at 180°C for 6½ h [Abdouss, M.; Sharifi‐Sanjani, N.; Bataille, P. J Appl Polym Sci 1999, 36, 10]. In the blends, OPP was used as a blend component and compared with PP over the whole concentration range. Pressed film blends of PP/OPP, PP/OPP/Talc, and PP/OPP/PA6 were examined by dynamic mechanical analyzer, thermal gravimetry analysis, and scanning electron microscopy. Mechanical properties such as tensile strength, modulus of elasticity, elongation, melt flow index, and hardness of the blends were measured. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2871–2883, 2004     

UV reactor performance modeling by Eulerian and Lagrangian methods

A study was performed to investigate the influence of hydrodynamics on the performance of ultraviolet (UV) reactors. Two general UV disinfection models were developed by integrating fluence rate models and inactivation kinetics within a commercial computational fluid dynamics (CFD) software package to predict reactor performances. Both a particle tracking (Lagrangian) random walk model and a volumetric reaction rate based (Eulerian) model were implemented. Simulations were performed for two characteristic annular single-lamp UV reactor configurations, with inlets concentric (L-shape) and normal (U-shape) to the reactor axis. Two fluence rate models, the infinite line source assumption and the finite line or multiple point source summation (MPSS), were used. First-order inactivation kinetics was assumed for disinfection, with rate constants from MS2 bacteriophage assays. The simulation results provided detailed information on the velocity profiles, reaction rates, range of absorbed dose, and areas of short circuiting of the UV reactors. Model predictions based on both the Lagrangian dose distribution and Eulerian concentration distribution were in good agreement with each other at high flow rates but showed some discrepancies at lower flow rates. Experimental verification of the general models was performed by simulating the disinfection performance of an industrial prototype UV reactor. Results from both integration approaches were shown to be in good agreement with the provided biodosimetry data.