Live Load Distribution Formulas for Single-Span Prestressed Concrete Integral Abutment Bridge Girders

In this study, live load distribution formulas for the girders of single-span integral abutment bridges (IABs) are developed. For this purpose, two and three dimensional finite-element models (FEMs) of several IABs are built and analyzed. In the analyses, the effects of various superstructure properties such as span length, number of design lanes, prestressed concrete girder size, and spacing as well as slab thickness are considered. The results from the analyses of two and three dimensional FEMs are then used to calculate the live load distribution factors (LLDFs) for the girders of IABs as a function of the above mentioned parameters. The LLDFs for the girders are also calculated using the AASHTO formulas developed for simply supported bridges (SSBs). The comparison of the analyses results revealed that LLDFs for girder moments and exterior girder shear of IABs are generally smaller than those calculated for SSBs using AASHTO formulas especially for short spans. However, AASHTO LLDFs for interior girder shear are found to be in good agreement with those obtained for IABs. Consequently, direct live load distribution formulas and correction factors to the current AASHTO live load distribution equations are developed to estimate the girder live load moments and exterior girder live load shear for IABs with prestressed concrete girders. It is observed that the developed formulas yield a reasonably good estimate of live load effects in prestressed concrete IAB girders.     

Influence of injection parameters and mold materials on mechanical properties of ABS in plastic injection molding

This study optimized effect of injection parameters such as melt temperature, packing pressure, cooling time and injection pressure on the mechanical properties of Acrylonitrile–Butadiene–Styrene (ABS) moldings. Mold materials having two different thermal conductivities, 191 W/mK for aluminum 2000 series and 50 W/mK for AISI 1020 at 25 °C were selected to use in experimental studies. Taguchi's L₉(3⁴) orthogonal array design was employed for the experimental plan. Mechanical properties of ABS specimens such as elasticity module, tensile strength and tensile strain at yield, tensile strain at break, flexural modules and izod impact strength (notched) were measured by using some test methods. Signal to noise ratio for mechanical properties of ABS using the Taguchi method was calculated and effect of the parameters on mechanical properties was determined using the analysis of variance. Linear mechanical models were also created by using regression analysis.     

Statistical evaluation of biodegradation of news ink vehicles and ink formulations

Soybean oil, commercial news ink vehicles—consisting of either soy or mineral oil and petroleum resins—and United States Department of Agriculture’s (USDA) 100% modified soy oil-based vehicles were subjected to biodegradation. Soybean oil and each vehicle were inoculated with monocultures and a mixed culture of Aspergillus fumigatus, Penicillium citrinum, and Mucor racemosus. Fermentations were allowed to proceed for 5, 12, and 25 d. Results show that, in 25 d, soy oil was degraded the most, followed by the USDA’s ink vehicles (USDA I–III), Newspaper Association of America’s (NAA) hybrid soy oil-based and commercial mineral oil-based vehicles. Some differences were found in the abilities of the cultures to degrade the different inks. Color did not appear to affect the degradation rate in soy oil, the USDA inks, or the NAA ink but was a factor in the commercial ink. Statistician.     

Lithographic and letterpress ink vehicles from vegetable oils

Our objectives for this study were to produce vegetable oil-based printing ink vehicles that did not require any petroleum components, which meet or exceed industry standards for rub-off resistance, viscosity and tackiness for a variety of printing applications. These objectives were satisfactorily met. Vehicles were completely compatible with carbon black, making them suitable for black ink formulations. In addition, the resulting vehicles had exceptionally light colors, and permitted formulations of colored inks that had substantially reduced pigment levels compared to industry standards.     

Cross-linkers control the viscoelastic properties of soybean oil-based biomaterials

Because of environmental concerns, biodegradable materials have been of increasing research interest over the last several years. Previously, we reported on a biobased material developed from epoxidized soybean oil (ESO) that displayed viscoelastic behavior similar to synthetic rubbers or plastics. In this work, the viscoelastic properties of several biomaterials made from ESO cross-linked by different amounts of two different cross-linking agents were investigated. The composites exhibited different glass transition temperatures and viscoelastic behaviors depending on the type and amount of cross-linker used. Higher glass transition temperatures and stronger viscoelastic properties of the materials were found with a greater amount of cross-linker. Comparing agent triethylene glycol diamine (TGD) with agent triethylenetriamine (TETA), we found that the material cross-linked by TETA had a higher glass transition temperature and stronger viscoelastic solid properties than the material cross-linked by the agent TGD.     

Drying properties of metathesized soybean oil

Soybean oil was metathesized with the standard homogenous metathesis catalyst, which consisted of tungsten hexachloride (WCl₆) and tetramethyl tin (Me₄Sn) in chlorobenzene as solvent. The reactions were terminated at different time intervals. Soybean oil was mixed with metathesized soybean oil in the presence of cobalt-drier to evaluate drying properties. Five weight percentage (% w) of metathesized oil was found to be all that was needed to decrease the drying time of soybean oil from 312 to 182 min. Drying times for heat-polymerized soybean oil with Gardner-Holdt viscosity of Z₁–Z₂ and Z₃–Z₄ were 71 and 75 min, respectively. In both cases, 5% weight metathesized soybean oil in the blend gave the best results for reducing drying time to 67 and 69 min, respectively. Statistician.     

An assignment model for dynamic load planning of intermodal trains

Intermodal terminals are important facilities in the container transport network, providing an exchange of containers between road and rail transport. Numerous factors can affect throughput in such highly integrated systems. These include numbers and types of equipment, physical layout, storage capacity and operating strategies. This study aims to improve operating strategies by developing an analytical tool to assist in load planning of container trains. The problem investigated can be described as a dynamic assignment problem with many uncertain parameters. Numerical investigations focus on tuning the proposed model to deal with the uncertainties.     

Prediction of chenille yarn and fabric abrasion resistance using radial basis function neural network models

The abrasion resistance of chenille yarn is crucially important in particular because the effect sought is always that of the velvety feel of the pile. Thus, various methods have been developed to predict chenille yarn and fabric abrasion properties. Statistical models yielded reasonably good abrasion resistance predictions. However, there is a lack of study that encompasses the scope for predicting the chenille yarn abrasion resistance with artificial neural network (ANN) models. This paper presents an intelligent modeling methodology based on ANNs for predicting the abrasion resistance of chenille yarns and fabrics. Constituent chenille yarn parameters like yarn count, pile length, twist level and pile yarn material type are used as inputs to the model. The intelligent method is based on a special kind of ANN, which uses radial basis functions as activation functions. The predictive power of the ANN model is compared with different statistical models. It is shown that the intelligent model improves prediction performance with respect to statistical models.     

Designing a road network for hazardous materials shipments

We consider the problem of designating hazardous materials routes in and through a major population center. Initially, we restrict our attention to a minimally connected network (a tree) where we can predict accurately the flows on the network. We formulate the tree design problem as an integer programming problem with an objective of minimizing the total transport risk. Such design problems of moderate size can be solved using commercial solvers. We then develop a simple construction heuristic to expand the solution of the tree design problem by adding road segments. Such additions provide carriers with routing choices, which usually increase risks but reduce costs. The heuristic adds paths incrementally, which allows local authorities to trade off risk and cost. We use the road network of the city of Ravenna, Italy, to demonstrate the solution of our integer programming model and our path-addition heuristic.     

Effect of alloy microstructure on electroless NiP deposition behavior on Alloy AZ91

Various magnesium alloys, which were assumed as reference to the individual behavior of each microstructural constituents of Alloy AZ91 in the coating bath, were designed to analyze the hypophosphite-reduced electroless nickel coating characteristics on them in both uncoupled and coupled conditions. Galvanic coupling of β phase to the matrix phase in the coating bath was observed to decelerate the deposition rate on the matrix phase. This behavior was attributed to the effective cathodic action of β phase in the coating bath as a result of the catalytic cathodic reactions on it. The variation in the Al content of the matrix phase was also estimated to affect the NiP deposition behavior due to the small scale galvanic interactions. The previously Ni nucleated sites on the alloy surface behaved as the most preferential sites for further Ni nucleation and growth. Low temperature heat treatment (230 °C for 2 h) caused a considerable increase in the surface hardness with negligible decrease in the corrosion resistance. High temperature heat treatment (400 °C for 1 h) improved the surface hardness further with significant deterioration in the corrosion resistance.