A methodology to model the information structure of an organization

The Integrated Computer Aided Manufacturing (ICAM) program of the U.S. Air Force identified a need to better communicate and analyze manufacturing for the people involved in improving productivity. To satisfy that need, the ICAM program developed the IDEF (ICAM Definition) method to address particular characteristics of manufacturing. This IDEF method is equally applicable in analyzing other types of organizations. IDEF comprises three modeling methodologies: function model methodology (IDEF₀), information model methodology (IDEF₁) and dynamics model methodology (IDEF₂). This paper reports on the Information model methodology only. This methodology is used to construct an information model that helps in understanding the structure of information needed to support the functions of an organization.     

Exact solution for a nonstatic cylindrically symmetric perfect fluid distribution in Einstein–Cartan theory

We consider a nonstatic, spin-polarized cylindrically symmetric perfect fluid distribution in the Einstein-Cartan theory and obtain the field equations. These field equations are solved using the Ray–Smalley energy-momentum tensor.     

Studying grain boundary regions in polycrystalline materials using spherical nano-indentation and orientation imaging microscopy

In this article, we report on the application of our spherical nanoindentation data analysis protocols to study the mechanical response of grain boundary regions in as-cast and 30% deformed polycrystalline Fe–3%Si steel. In particular, we demonstrate that it is possible to investigate the role of grain boundaries in the mechanical deformation of polycrystalline samples by systematically studying the changes in the indentation stress–strain curves as a function of the distance from the grain boundary. Such datasets, when combined with the local crystal lattice orientation information obtained using orientation imaging microscopy, open new avenues for characterizing the mechanical behavior of grain boundaries based on their misorientation angle, dislocation density content near the boundary, and their propensity for dislocation source/sink behavior.     

Large Eddy Simulations of Double-Ruler Electromagnetic Field Effect on Transient Flow During Continuous Casting

Transient flow during nominally steady conditions is responsible for many intermittent defects during the continuous casting of steel. The double-ruler electromagnetic field configuration, or “FC-Mold EMBr,” is popular in commercial slab casting as it provides independent control of the applied static field near the jet and free surface regions of the mold. In the current study, transient flow in a typical commercial caster is simulated in the absence and in the presence of a double-ruler magnetic field, with rulers of equal strengths. Large eddy simulations with the in-house code CU-FLOW resolve the important transient behavior, using grids of over five million cells with a fast parallel solver. In the absence of a magnetic field, a double-roll pattern is observed, with transient unbalanced behavior, high surface velocities (~0.5 m/s), surface vortex formation, and very large surface-level fluctuations (~±12 mm). Applying the magnetic field suppresses the unbalanced behavior, producing a more complex mold flow pattern, but with much lower surface velocities (~0.1 m/s), and a flat surface level with small level fluctuations (<±1 mm). Nail board measurements taken at this commercial caster, in the absence of the field, matched reasonably well with the calculated results, both quantitatively and qualitatively.     

Genetic algorithm based multi-objective reliability optimization in interval environment

In most of the real world design or decision making problems involving reliability optimization, there are simultaneous optimization of multiple objectives such as the maximization of system reliability and the minimization of system cost, weight and volume. In this paper, our goal is to solve the constrained multi-objective reliability optimization problem of a system with interval valued reliability of each component by maximizing the system reliability and minimizing the system cost under several constraints. For this purpose, four different multi-objective optimization problems have been formulated with the help of interval mathematics and our newly proposed order relations of interval valued numbers. Then these optimization problems have been solved by advanced genetic algorithm and the concept of Pareto optimality. Finally, to illustrate and also to compare the results, a numerical example has been solved.     

Hydrogen storage in TiO2 functionalized (10, 10) single walled carbon nanotube (SWCNT) – First principles study

Hydrogen storage in titanium dioxide (TiO₂) functionalized (10, 10) armchair single walled carbon nanotube (SWCNT) is investigated through first principle calculations using density functional theory (DFT). This first principles study uses Vienna Ab-initio Simulation Package (VASP) with ultrasoft pseudopotentials and local density approximation (LDA). The necessary benchmark and other systematic calculations were carried out to project the hydrogen storage capability of the designed system. Interestingly, the TiO₂ molecules functionalized on the outer surface of SWCNT do not undergo any dimerization/clustering thus giving excellent stability and usable gravimetric hydrogen storage capacity of 5.7 wt.% and the value nearly fulfills the US DOE target (i.e. 6 wt.%). The band structure and density of states (DOS) plots suggest that the functionalization can lead a way to transform the nature (metallic → semiconducting) of the pristine SWCNT. The nominal values of H₂ storage capacity and binding energies give much hope for using CNT functionalized with TiO₂ as a practical and reversible hydrogen storage medium (HSM).     

An environmentally sustainable manufacturing network model under an international ecosystem

Clean Technologies and Environmental Policy - There is a growing consensus that the increase in greenhouse gases results in unfavorable changes to the Earth’s climate and is responsible for...     

Recovery of metals and other beneficial products from coal fly ash: a sustainable approach for fly ash management

International Journal of Coal Science & Technology - Increasing production and disposal of coal fly ash (CFA) is a matter of serious environment concern. However, CFA contains various...     

WO3 nano-ribbons: their phase transformation from tungstite (WO3·H2O) to tungsten oxide (WO3)

Tungsten oxide (WO₃) nano-ribbons (NRs) were obtained by annealing tungstite (WO₃·H₂O) NRs. The latter was synthesized below room temperature using a simple, environmentally benign, and low cost aging treatment of precursors made by adding hydrochloric acid to diluted sodium tungstate solutions (Na₂WO₄·2H₂O). WO₃ generates significant interests and is being used in a growing variety of applications. It is therefore important to identify suitable methods of production and better understand its properties. The phase transformation was observed to be initiated between 200 and 300 ^°C, and the crystallographic structure of the NRs changed from orthorhombic WO₃·H₂O to monoclinic WO₃. It was rigorously studied by annealing a series of samples ex situ in ambient air up to 800 ^°C and characterizing them afterward. A temperature-dependent Raman spectroscopy study was performed on tungstite NRs between minus 180 and 700 ^°C. Also, in situ heating experiments in the transmission electron microscope allowed for the direct observation of the phase transformation. Powder X-ray diffraction, electron diffraction, electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize precisely this transformation.