Analysis of girder bridge pier subjected to barge collision considering the superstructure interactions: the case study of a multiple-pier bridge system

This paper aims to numerically evaluate the effects of girder bridge superstructure on the impact responses and load paths transferring the shear force of pier subjected to a moderate-energy barge collision in LS-DYNA. First, two multiple-pier systems of St. George Island Bridge in Florida which have different piers in terms of structural characteristics (such as mass and stiffness), geometry, and the height of impact location are considered as the cases of study. From the numerical barge collision simulations, different impact responses and load transferring paths from the impact location to farther zones are observed. In addition, the sensitivity of impact responses, and the impact load paths transferring shear force to the superstructure mass, stiffness, and damping are studied by developing four different models of pier-superstructure interaction and carrying out a parametric study. It is found that the increase in the value of superstructure parameters has positive effects on the impact forces and the internal stresses in the piers. However, the sensitivity of shear stresses generated at various zones of the pier extremely depends on the impact load paths transferring shear force in different piers with different relative characteristics rather than the superstructure.     

Modeling Grain Size and Strain Rate in Linear Friction Welded Waspaloy

The high-temperature deformation behavior of the Ni-base superalloy, Waspaloy, using uniaxial isothermal compression testing was investigated at temperatures above the γ′ solvus, 1333 K, 1373 K, and 1413 K (1060 °C, 1100 °C, and 1140 °C) for constant true strain rates of 0.001, 0.01, 0.1, and 1 s^?1 and up to a true strain of 0.83. Flow softening and microstructural investigation indicated that dynamic recrystallization took place during deformation. For the investigated conditions, the strain rate sensitivity factor and the activation energy of hot deformation were 0.199 and 462 kJ/mol, respectively. Constitutive equations relating the dynamic recrystallized grain size to the deformation temperature and strain rate were developed and used to predict the grain size and strain rate in linear friction-welded (LFWed) Waspaloy. The predictions were validated against experimental findings and data reported in the literature. It was found that the equations can reliably predict the grain size of LFWed Waspaloy. Furthermore, the estimated strain rate was in agreement with finite element modeling data reported in the literature.     

Beneficial Reuse of FGD Material in the Construction of Low Permeability Liners: Impacts on Inorganic Water Quality Constituents

In this paper, we examine the water quality impacts associated with the reuse of fixated flue gas desulfurization (FGD) material as a low permeability liner for agricultural applications. A 0.457-m-thick layer of fixated FGD material from a coal-fired power plant was utilized to create a 708?m2 swine manure pond at the Ohio Agricultural Research and Development Center Western Branch in South Charleston, Ohio. To assess the effects of the fixated FGD material liner, water quality samples were collected over a period of 5?years from the pond surface water and a sump collection system beneath the liner. Water samples collected from the sump and pond surface water met all Ohio nontoxic criteria, and in fact, generally met all national primary and secondary drinking water standards. Furthermore it was found that hazardous constituents (i.e., As, B, Cr, Cu, and Zn) and agricultural pollutants (i.e., phosphate and ammonia) were effectively retained by the FGD liner system. The retention of As, B, Cr, Cu, Zn, and ammonia was likely due to sorption to mineral components of the FGD liner, while Ca, Fe, and P retention were a result of both sorption and precipitation of Fe- and Ca-containing phosphate solids.     

Electromagnetic micro energy harvester for human locomotion

This paper reports the design and characterization of a proposed electromagnetic harvester. The harvester is made of permanent magnets and the overall size is of AA battery. Using Faraday’s law of induction, the harvester is capable of producing vibrational energy into electrical energy at low frequencies. The proposed harvester is to be used for bio-medical devices such as pacemakers and hearing aids. Human locomotion is the main source of vibrational energy that will be harnessed. Magnetic harvester can be attached anywhere on the human body in presence of motion such as mounting on the boot when walking. For low frequencies of 0–35 Hz and displacement of 0–7.2 mm, the micro harvester is capable of producing power anywhere from 0 to 38 mW at 0–35 Hz with power density of $4.44 \times 10^{ - 4} {\text{W}}/{\text{cm}}^{3}$ 4.44 × 10 ? 4 W / cm 3 .     

A part-level learning strategy for JPEG image recompression detection

Multimedia Tools and Applications - Recompression is a prevalent form of multimedia content manipulation. Different approaches have been developed to detect this kind of alteration for digital...     

Cyber physical systems for predictive production systems

As disruptive technologies like Industry 4.0 and Internet of Things advance at a breakneck speed, modern manufacturing is ready to embrace the systematic deployment of predictive production systems. The predictive production system is an intelligent manufacturing system where networked assets are equipped with self-awareness to predict, root cause, and reconfigure faulty events automatically. Cyber physical systems are one of the core enabling technologies within which information from all the related perspectives are analyzed and interconnected between physical factory floor and the cyber computational space. It intertwines with smart analytics to comprehend invisible issues for rapid decision making. In this paper, a systematic approach is proposed on how cyber physical systems can be applied to predictive production systems to inject resilience and interoperability so that the productivity of manufacturing can be optimized.     

Direction of arrival accuracy improvement through estimation of spatial coherence loss function in non-homogeneous environments

Performance of direction of arrival (DOA) estimation is significantly degraded in practical situations. One of the conditions that decreases its performance, is the coherent loss caused by the propagation of the wavefront through random non-homogeneous media. Most of the previous methods, such as matrix fitting method and covariance matching technique, need the multidimensional search; therefore their computations are difficult and not suitable for a real-time application. In this paper, a three-stage method based on the generalised eigenvalues utilising signal subspace eigenvectors (GEESE) and Gauss–Newton (GN) algorithms, namely 3SM/GE-GN, is presented. Simulation results show the effectiveness of the proposed method. Difference of RMSE of DOA estimation between proposed method, which is independent of the coherent loss, and other methods is more clearly visible in higher snapshots. As well, in fixed snapshot, the RMSE of the proposed method is lower than others in different SNRs. Furthermore, the computational time of the simulation is very lower than two previous works.