Integrated design optimization research and development in an industrial environment

An overview is given of a design optimization project that is in progress at the GE Research and Development Center for the past few years. The objective of this project is to develop a methodology and a software system for design automation and optimization of structural/mechanical components and systems. The effort focuses on research and development issues and also on optimization applications that can be related to real-life industrial design problems. The overall technical approach is based on integration of numerical optimization techniques, finite element methods, CAE and software engineering, and artificial intelligence/expert systems (AI/ES) concepts. The role of each of these engineering technologies in the development of a unified design methodology is illustrated. A software system DESIGN-OPT has been developed for both size and shape optimization of structural components subjected to static as well as dynamic loadings. By integrating this software with an automatic mesh generator, a geometric modeler and an attribute specification computer code, a software module SHAPE-OPT has been developed for shape optimization. Details of these software packages together with their applications to some 2- and 3-dimensional design problems are described

Can re-entrance be observed in force induced transitions?

A large conformational change in the reaction co-ordinate and the role of the solvent in the formation of base-pairing are combined to settle a long standing issue {\it i.e.} prediction of re-entrance in the force induced transition of DNA. A direct way to observe the re-entrance, i.e a strand goes to the closed state from the open state and again to the open state with temperature, appears difficult to be achieved in the laboratory. An experimental protocol (in direct way) in the constant force ensemble is being proposed for the first time that will enable the observation of the re-entrance behavior in the force-temperature plane. Our exact results for small oligonucleotide that forms a hairpin structure provide the evidence that re-entrance can be observed.Comment: 12 pages and 5 figures (RevTex4). Accepted in Europhys Lett. (2009

Anomalous Raman scattering from phonons and electrons of superconducting FeSe0.82_{0.82}

We report interesting anomalies in the temperature dependent Raman spectra of FeSe$_{0.82}$ measured from 3K to 300K in the spectral range from 60 to 1800 cm$^{-1}$ and determine their origin using complementary first-principles density functional calculations. A phonon mode near 100 cm$^{-1}$ exhibits a sharp increase by $\sim$ 5% in frequency below a temperature T$_s$ ($\sim$ 100 K) attributed to strong spin-phonon coupling and onset of short-range antiferromagnetic order. In addition, two high frequency modes are observed at 1350 cm$^{-1}$ and 1600 cm$^{-1}$, attributed to electronic Raman scattering from ($x^2-y^2$)to $xz$ / $yz$ $d$-orbitals of Fe.Comment: 19 pages, 4 figures, 1 tabl

Classical Langevin dynamics of a charged particle moving on a sphere and diamagnetism: A surprise

It is generally known that the orbital diamagnetism of a classical system of charged particles in thermal equilibrium is identically zero -- the Bohr-van Leeuwen theorem. Physically, this null result derives from the exact cancellation of the orbital diamagnetic moment associated with the complete cyclotron orbits of the charged particles by the paramagnetic moment subtended by the incomplete orbits skipping the boundary in the opposite sense. Motivated by this crucial, but subtle role of the boundary, we have simulated here the case of a finite but \emph{unbounded} system, namely that of a charged particle moving on the surface of a sphere in the presence of an externally applied uniform magnetic field. Following a real space-time approach based on the classical Langevin equation, we have computed the orbital magnetic moment which now indeed turns out to be non-zero, and has the diamagnetic sign. To the best of our knowledge, this is the first report of the possibility of finite classical diamagnetism in principle, and it is due to the avoided cancellation.Comment: Accepted for publication in EP

PUGAI (FUMIGATION) AS A PURA MARUTHUVAM (EXTERNAL THERAPY) IN THE SIDDHA SYSTEM OF MEDICINE

Siddha Medicine is a traditional system of healing medicine in the southern part of the India and some other nations. This system of Medicine is mainly categorized into two classes, based on the root of admiration of the drugs, which are 32 types of Aga marunthugal (Internal medicine) and 32 types of Pura marunthugal (External medicine) for treating the 4448 diseases describe in the Siddha texts. The 32 types of External therapies are included in many kinds of external application of treatment procedures. Siddha texts mentioned the Pugai is termed as Fumigation is one of the external therapies in this system. This study reveals that the Pugai is the effective external treatment procedure to cure some disease condition based on Siddha theory. Fumigation signifies the artificial impregnation of the atmosphere, with the fumes or smoke of any vegetable or aromatic substances. Pugai is an application of fumes is administered in different parts of the body, apart from inhalation. Most of these therapies are aimed to maintaining the healthy balance of tri humours of Vatham, Pitham, Kabam and Saptha thathukkal which mean seven tissue types of the body. Main purpose of this procedure is to reduce microbes and to control infections. Fumigation can be effective in inactivating microbes on environmental surfaces

The Gordon-Haus effect for modified NLS solitons

Random jitter in the soliton arrival time (the Gordon-Haus effect) is analyzed for solitons being solutions of the integrable modified nonlinear Schroedinger equation. It is shown that the mean square fluctuation of the soliton position depends on the soliton parameters which can be properly adjusted to suppress the Gordon-Haus jitter.Comment: LaTeX, 7 pages, 3 figures, to be published in Europhys. Let

A general scheme for modeling gamma-ray burst prompt emission

We describe a general method for modeling gamma-ray burst prompt emission. We find that for the burst to be produced via the synchrotron process unphysical conditions are required -- the distance of the source from the center of the explosion ($R_\gamma$) must be larger than $\sim 10^{17}$cm and the source Lorentz factor \gta 10^3; for such a high Lorentz factor the deceleration radius ($R_d$) is less than $R_\gamma$ even if the number density of particles in the surrounding medium is as small as $\sim 0.1$ cm$^{-3}$. The result, $R_\gamma > R_d$, is in contradiction with the early x-ray and optical afterglow data. The synchrotron-self-Compton (SSC) process fares much better. There is a large solution space for a typical GRB prompt emission to be produced via the SSC process. The prompt optical emission accompanying the burst is found to be very bright (\lta 14 mag; for $z\sim2$) in the SSC model, which exceeds the observed flux (or upper limit) for most GRBs. Continuous acceleration of electrons can significantly reduce the optical flux and bring it down to the observed limits. (Abridged)Comment: Published in MNRAS Jan 2008, 56 page

Laboratory Column flotation studies for reduction of alumina and silica in iron ore slimes of an operating plant

A typical iron ore washing plant for treating iron ore fines (<10 mm) consist of sizing of the ore by dry / wet screening, washing, classification by screw classifiers followed by single or multi-stage hydrocycloning of screw classifiers overflow. The underflow of the hydrocyclones forms the concentrate which is suitable for pellets making. Since the cut-point of hydrocyclones is usually at 20 µm or less, relatively lower diameter cyclones in a cluster with parallel feeding are used. This is found to, often, result in choking of the spigots, at times, by extraneous material reporting along with the slurry. It is observed to lead to sub-optimum performance of the cyclones with loss of iron values into cyclone overflow and thereafter into tailings. Analysis of the data of an operating beneficiation plant (Beneficiation plant - 1) of M/s Jindal South West (JSW) Steel Limited, Karnataka, India over a period of one year indicated that weight recovery of the concentrate from two-stage hydrocycloning was 45.9% (with respect to feed to the cyclones) and assaying 63.43% Fe, 4.43% SiO2 and 2.23% Al2O3. Considering the fineness of the slimes (d80: 40.5 µm), generated as screw classifier overflow, flotation is thought to be better alternative vis-à-vis hydrocyclones to recover iron values from it. The present study aims at improving the recovery of the iron values from the screw classifier overflow by adopting reverse cationic column flotation technology. After selecting a suitable collector, process parameters like collector and depressant dosages are optimized by statistically designed experiments on a Denver D12 flotation cell. Later, the effect of important operating parameters of flotation column like air flow-rate, froth depth and wash water on the separation process is studied and optimized. It was established that a typical screw classifier overflow analyzing 60.43% Fe, 6.88% SiO2 and 3.26% Al2O3 could be improved to 63.30% Fe, 4.04% SiO2 and 2.32% Al2O3 with 59.10% weight and 61.70% Fe recovery. This is an improvement of 29% in weight recovery of the concentrate at equivalent metallurgy compared to what is being obtained, by two-stage cycloning