Integration of instrumental neutron activation analysis and inductively coupled plasma-optical emission spectrometry with mathematical modeling for the elemental analysis of plants

Metals in fourteen plants were analyzed in parallel by instrumental neutron activation analysis (INAA) and inductively coupled plasma-optical emission spectrometry (ICP-OES) for the possible integration of the analytical techniques. INAA correlates well with ICP-OES for Ca, K, Fe, Mn, Mg, and Zn. Advantages of INAA include its nondestructive nature and ease of sample preparation. ICP-OES requires destructive sample digestion, but provides superior limits of detection. Therefore, ICP-OES is the method of the choice for low elemental concentrations. In general, ICP-OES is a better choice for Cr, Sr, and Cu in plant analysis for accuracy. On the other hand, a simple mathematical model was developed for predicting the concentrations of Cu and Cr that were measured by INAA. The predicted values of the elements showed consistency to their corresponding certified values as well as to the concentrations measured by ICP-OES, specifically for Cu or when the concentrations exceeded 5?mg/kg.     

Dynamic instability analysis of doubly clamped cylindrical nanowires in the presence of Casimir attraction and surface effects using modified couple stress theory

The dynamic instability of free-standing size-dependent nanowires by considering the Casimir forceand surface effects is investigated in the following research work. The study is carried out for nanosystemswith circular cross section and cylinder–plate geometry for which the governing equation of motion is derivedbased on the Gurtin–Murdoch model and modified couple stress theory. Two methods including the proximityforce approximation for small separations and Dirichlet asymptotic approximation for large separations areutilized to formulate the Casimir attraction of a free-standing cylinder–plate geometry. To solve the complexnonlinear problem faced in this work, a stepwise numerical procedure is developed and the effects of lengthscale parameter, surface energy and vacuum fluctuations on the dynamic instability and adhesion time ofnanowires are studied. Based on the obtained results, the phase portrait of Casimir-induced nanowires showsperiodic and homoclinic orbits.     

Modeling of metastable phase formation diagrams for sputtered thin films

A method to model the metastable phase formation in the Cu–W system based on the critical surface diffusion distance has been developed. The driver for the formation of a second phase is the critical diffusion distance which is dependent on the solubility of W in Cu and on the solubility of Cu in W. Based on comparative theoretical and experimental data, we can describe the relationship between the solubilities and the critical diffusion distances in order to model the metastable phase formation. Metastable phase formation diagrams for Cu–W and Cu–V thin films are predicted and validated by combinatorial magnetron sputtering experiments. The correlative experimental and theoretical research strategy adopted here enables us to efficiently describe the relationship between the solubilities and the critical diffusion distances in order to model the metastable phase formation during magnetron sputtering.     

Characterization of twin-like structure in a ferrite-based lightweight steel

The present study examined cold to warm compressive deformation behavior of a ferrite- based lightweight steel through characterization of the banded structures. Compression tests were carried out at 25 to 500 °C at a strain rate of 0.01 s^-1 up to true strain of 0.6. Analysis of the microstructural evolution using electron back scatter diffraction indicated that the twin-like bands in the large ferrite grains occurred with the {112}[111] system at a 60° misorientation. Density of the twin-like bands is increased by raising the deformation temperature. EBSD results showed that the primary and secondary twins occurred in the [-11-1] and [1-1-1] directions. In addition, the strain at 500 °C distorted the twin-like bands and resulted in wavy boundaries. The strain hardening behavior was also examined using the Crussard-Jaoul (C-J) model and the n-values were calculated for each stage of imposing strain. The results showed high dislocation density in the adjacent of twin-like boundaries intersections which resulted in the n-value increment.     

Spanning trees with minimum weighted degrees

Given a metric graph G, we are concerned with finding a spanning tree of G where the maximum weighted degree of its vertices is minimum. In a metric graph (or its spanning tree), the weighted degree of a vertex is defined as the sum of the weights of its incident edges. In this paper, we propose a 4.5-approximation algorithm for this problem. We also prove it is NP-hard to approximate this problem within a 2−ε factor.     

An architecture for scheduling with the capability of minimum share to heterogeneous Hadoop systems

The Journal of Supercomputing - Job scheduling in Hadoop has been thus far investigated in several studies. However, some challenges including minimum share (min-share), heterogeneous cluster,...     

Frequency-interval control configuration selection for multivariable bilinear systems

Control configuration selection is the procedure of choosing the appropriate input and output pairs for the design of decoupled (SISO or block) controllers for multivariable systems. This step is an important prerequisite for a successful industrial control strategy. The focus of this paper is on the problem of control configuration selection for a class of nonlinear systems which is known as bilinear systems. First, new frequency-interval gramians are presented for bilinear systems. These gramians are devised in particular for many applications in which one is interested in analysis and control of a system within a frequency-interval. It is shown that these gramians are the solutions to the so-called frequency-interval generalized Lyapunov equations. These gramians are used in the interaction measure for control configuration selection of MIMO bilinear systems. Most of the results on control configuration selection, which have been proposed so far, can only support linear systems. The proposed gramian-based interaction measure supports bilinear processes, can show the input–output interactions for any frequency-interval of interest, and can be used to propose a richer sparse or block diagonal controller structure.