Insertion based Lin–Kernighan heuristic for single row facility layout

The single row facility layout problem (SRFLP) is the problem of arranging facilities with given lengths on a line, while minimizing the weighted sum of the distances between all pairs of facilities. The problem is known to be NP-hard. In this paper, we present a neighborhood search heuristic called LK-INSERT which uses a Lin–Kernighan neighborhood structure built on insertion neighborhoods. To the best of our knowledge this is the first such heuristic for the SRFLP. Our computational experiments show that LK-INSERT is competitive for most instances, and it improves the best known solutions for several large sized benchmark SRFLP instances.     

Vibrational Spectroscopy of Na–H Complexes in ZnO

Sodium acceptors were diffused into ZnO bulk single crystals to a depth of ~1μm, with a near-surface concentration of ~10¹⁸–cm³. An O–H local vibrational mode (LVM) was observed at 3304–cm^–1, at a temperature of 9 K, in hydrogenated samples. The LVM is attributed to an O–H bond-stretching mode adjacent to a Na acceptor. When deuterium substitutes for hydrogen, a peak is observed at 2466–cm^–1. The isotopic frequency ratio is similar to values found in other hydrogen complexes. In the deuterated sample, a sideband at 2461–cm^–1 is attributed to a Fermi resonance.     

Novel low-temperature growth of SnO2 nanowires and their gas-sensing properties

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Negative ion beam extraction in ROBIN

The RF based single driver ?ve ion source experiment test bed ROBIN (Replica Of BATMAN like source in INDIA) has been set up at Institute for Plasma Research (IPR), India in a technical collaboration with IPP, Garching, Germany. A hydrogen plasma of density 5 × 10¹² cm^?3 is expected in driver region of ROBIN by launching 100 kW RF power into the driver by 1 MHz RF generator. The cesiated source is expected to deliver a hydrogen negative ion beam of 10 A at 35 kV with a current density of 35 mA/cm² as observed in BATMAN.In first phase operation of the ROBIN ion source, a hydrogen plasma has been successfully generated (without extraction system) by coupling 80 kW RF input power through a matching network with high power factor (cos θ > 0.8) and different plasma parameters have been measured using Langmuir probes and emission spectroscopy. The plasma density of 2.5 × 10¹¹ cm^?3 has been measured in the extraction region of ROBIN. For negative hydrogen ion beam extraction in second phase operation, extraction system has been assembled and installed with ion source on the vacuum vessel. The source shall be first operated in volume mode for negative ion beam extraction. The commissioning of the source with high voltage power supply has been initiated.     

Large dynamic range nanopositioning using iterative learning control

This paper presents the control system design and tracking performance for a large range single-axis nanopositioning system that is based on a moving magnet actuator and a flexure bearing. While the physical system is designed to be free of friction and backlash, the nonlinearities in the electromagnetic actuator as well as the harmonic distortion in the drive amplifier degrade the tracking performance for dynamic commands. It is shown that linear feedback and feedforward proves to be inadequate to overcome these nonlinearities. This is due to the low open-loop bandwidth of the physical system, which limits the achievable closed-loop bandwidth given actuator saturation concerns. For periodic commands, like those used in scanning applications, the component of the tracking error due to the system nonlinearities exhibits a deterministic pattern and repeats every period. Therefore, a phase lead type iterative learning controller (ILC) is designed and implemented in conjunction with linear feedback and feedforward to reduce this periodic tracking error by more than two orders of magnitude. Experimental results demonstrate the effectiveness of ILC in achieving 10 nm RMS tracking error over 8 mm motion range in response to a 2 Hz band-limited triangular command. This corresponds to a dynamic range of more than 10⁵ for speeds up to 32 mm/s, one of the highest reported in the literature so far, for a cost-effective desktop-sized single-axis motion system.     

Polymer‐ and wax‐based monoconcentrate predispersed pigments in the colouring of plastics

Over the past few decades, masterbatch production has been increasing year by year. Pigments are used primarily in masterbatches because of their ability to impart colour or opacity to a matrix. The effectiveness of pigments depends not only on their intrinsic ability to absorb or scatter light, but also, importantly, on the dispersiblity and distribution of the pigments that can be achieved in plastics. Nowadays, stringent environmental as well as excellent quality controls are making inevitable the use of non‐dusty monoconcentrated predispersed pigments for the production of masterbatches for the colouring of plastics. Commercially, for the most part, two types of monoconcentrated predispersed pigments are being used for the colouring of thermoplastic masterbatches. These are polymer‐ and wax‐based predispersed pigments. This study has been undertaken to provide a comparison of the colouring properties of polymer‐ and wax‐based monoconcentrated predispersed pigments. Four commercially used organic pigments have been selected. Both types of monoconcentrate predispersed pigments have been developed on a co‐rotating twin‐screw compounding extruder with a length/diameter ratio of 44. A detailed analysis on the comparison of the colouring properties is presented. Results indicate that good colour properties are achieved when operating conditions are optimised.     

A study on composites from phenol‐formaldehyde‐casein resin

A modified phenol‐formaldehyde (PF) resin was synthesized under alkaline condition in varying proportion of casein up to 20% (w/w) of phenol. All the prepared resins were characterized by free phenol content, free formaldehyde content, viscosity measurements, number average molecular weight determination by conductometry and Infrared Spectroscopy (IR). Their curing kinetics was studied isothermally and by differential scanning calorimetry (DSC) on dynamic runs. The resin samples were cured using concentrated hydrochloric acid and hexamine individually. Cured resins were characterized by IR and Thermogravimetry (TGA). Glass fabric reinforced composites (GFRC) were fabricated by maintaining 40 : 60 proportion of resin to reinforcement material. The laminates thus formed were characterized for their mechanical properties and chemical resistance. Enhancements in thermal stability of the resin as well as toughness of composite with increase in casein content were observed for the resins studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Antimicrobial and nuclease activity of mixed polypyridyl ruthenium(II) complexes

The ruthenium(II) complexes with 2,9-dimethyl-1,10-phenanthroline (dmphen) and terpyridine derivatives have been synthesized and screened for their antimicrobial potency. The interaction of these complexes with Herring Sperm DNA was investigated by thermal denaturation, viscosity measurements, gel electrophoresis and spectrophotometric methods. The results indicate that the complexes bound to DNA via partial intercalative mode. The salt-dependent binding of these complexes has been determined by UV–Vis spectrophotometric titration. The contribution of the non-electrostatic binding free energy (ΔG_t^o) to the total binding free energy change (ΔG^o) is found to be ~ 88% at [Na⁺] = 0.075 M. The large value suggests that the stabilization of the DNA binding is mostly due to the contribution of non-electrostatic process.