Hardened slag–cement pastes of various porosities. II. Water and nitrogen adsorption

Specific surface areas and pore structure studies were carried out on hardened slag-cement pastes. Water and nitrogen adsorption isotherms were measured, and the derived parameters were critically compared. Nitrogen areas and total pore volumes were found to be much smaller than water values. For water vapour adsorption, the specific surface areas derived from the adsorption branches are found to be lower than those derived from the resorption isotherms. Some evidence is presented in this paper that the surface area values derived along the adsorption branches are underestimated values, and that the resorption values might be considered to be nearer to the actual areas of the various pastes. Calculations of the hydraulic radii refute the hypothesis that the areas inaccessible to nitrogen are interlayer areas.     

Hardened alite pastes of various porosities. I. Degree of hydration,compressive strength and total porosity

The alite used in this investigation was synthesised from the stoichiometric mixture at 1550°C. The hardened alite pastes were made using initial water/alite ratios of 0.20, 0.30, 0.45 and 0.60. Degree of hydration, compressive strength and total porosity were estimated at various hydration time intervals of 0.5 h, 2 h, 6 h, 1 day, 3 days, 7 days and 28 days. A meaningful relation between compressive strength and water/alite ratio was established at constant values of degree of hydration, total porosity and Powers' gel-space ratio.     

Synthesis and characterisation of monomethine cyanine dyes based on N-bridgehead heterocycles

In this paper, the synthesis and spectral properties of novel asymmetrical and symmetrical monomethine cyanine dyes are described. Reaction of phenylpyrazolones and oxazolones with acetyl thiourea and/or thiosemicarbazide afforded acetyl intermediate compounds which were then reacted with metal divalent chlorides, followed by reaction with N -methyl hetetrocyclic quaternary salts, to give asymmetrical monomethine cyanine dyes. Reaction of the 5-amino derivative of the intermediate compounds with acetaldehyde followed by reaction with N -methyl hetetrocyclic quaternary salts produced the symmetrical monomethine cyanine dyes. These new compounds were characterised with elemental analyses, visible absorption and infrared spectrometry, and ¹H/¹³C NMR and mass spectroscopy. The correlation between the colour and structure of these dyes was also investigated.     

Object joint detection and tracking using adaptive multiple motion models

This paper deals with the problem of detecting objects that may switch between different motion models. In order to accurately detect these moving objects taking into account possible changing motion models, we propose an adaptive multi-motion model in the joint detection and tracking (JDT) framework. The proposed technique differs from the existing JDT-based methods mainly in two ways. First we express the solution in the JDT framework via a formulation in the multiple motion model setting. Second, we introduce a new motion model prediction function which exploits the correlation between the motion model and object kinematic state. Experiments on both synthetic and real videos demonstrate that the JDT method employing the proposed adaptive multi-motion model can detect objects more accurately than the existing peer methods when objects change their motion models.     

Glycidyl methacrylate as a new host material for laser dyes

This article reports on the laser action of pyrromethene 597 and pyrromethene 567 doped in the novel solid polymeric matrix glycidyl methacrylate. Mirrorless lasing was observed when samples with diameters of 10 mm and lengths of 20 mm, with different dyes concentrations, were transversely pumped at 532 nm. The influence of the dye concentration on the laser measurements included the peak wavelengths, output energies, conversion efficiencies, and laser gains. Relatively high lasing efficiencies (up to ～ 60%) were obtained from these new polymeric materials with very good photostability, where a decrease of only 65% in the initial laser output energy was observed after pumping by 60,000 shots of 15 mJ at 10 Hz. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 59–63, 2007     

Brain-targeted intranasal zaleplon solid dispersion in hydrophilic carrier system; 23 full-factorial design and in vivo determination of GABA neurotransmitter

Intranasal zaleplon solid dispersion was formulated to enhance the solubility, bioavailability and deliver an effective therapy. Zaleplon belongs to Class II drugs, and undergoes extensive first-pass metabolism after oral absorption exhibiting 30% bioavailability. A 2³ full-factorial design was chosen for the investigation of solid dispersion formulations. The effects of different variables include drug to carrier ratio (1:1 and 1:2), carrier type (polyethylene glycol 4000 and poloxamer 407), and preparation method (solvent evaporation and freeze drying) on different dissolution parameters were studied. The dependent variables determined from the in vitro characterization and their constraints were set as follows: minimum mean dissolution time, maximum dissolution efficiency and maximum percentage release. Numerical optimization was performed according to the constraints set based on the utilization of desirability functions. Differential scanning calorimetry, infrared spectroscopy, X-ray diffraction and scanning electron microscopy were performed. Ex vivo estimation of nasal cytotoxicity and assessment of the γ-aminobutyric acid level in plasma and brain 1?h after nasal SD administration in rabbits compared to the oral market product were conducted. The selected ZP-SD, with a desirability 0.9, composed of poloxamer 407 at drug to carrier ratio 1:2 successfully enhanced the bioavailability showing 44% increase in GABA concentration than the marketed tablets.     

EDM of Ti-6Al-4V: Electrode and polarity selection for minimum tool wear rate and overcut

Titanium and its alloys especially Ti-6Al-4V are being widely used numerous application areas. In addition to have iconic properties, Ti-6Al-4V is considered as challenging material in machining perspective that is why it has captured global research focus. In this research, electric discharge machining of Ti-6Al-4V has been carried out by employing four different types of electrode materials (graphite, aluminum, copper, and brass) assigned with two alternate polarities (positive and negative). Selection of the most appropriate tool material and electrode polarity is the important aspect needed to be explored for this alloy. In addition to polarity, discharge current, and pulse time ratio have been considered as process variables owing to have their direct influence in electric discharge machining. Taguchi L9 array has been employed for each of the four electrodes with positive polarity and similarly L9 with negative polarity. Thus, a total number of 72 experiments have been conducted. Tool wear rate and overcut (OC) around the machined surfaces are the response characteristics to be investigated in order to achieve minimum amounts of both of these two responses. Selection of the most suitable tool with common tool polarity has been carried out meeting the decision criteria of minimum tool wear and minimum OC.     

First-Principles Prediction of Structural,Magnetic, Electronic,and Elastic Properties of Full-Heusler Compounds Co<Subscript>2</Subscript>YIn (Y = Ti,V)

Density functional theory based on the full-potential linearized augmented plane wave (FP-LAPW) method is used to investigate the structural, magnetic, electronic, and elastic properties of Heusler alloys Co₂YIn (Y = Ti, V). It is shown that the calculated spin magnetic moments using the local spin-density approximation (LSDA), generalized gradient approximation (GGA), LSDA + U, and Tran–Blaha (TB)-modified Becke–Johnson (mBJ)-local density approximations (LDA) are in good agreement with the Slater–Pauling rule. The obtained results with LSDA, GGA-PBE, and LSDA + U of the density of states illustrate that both compounds have a metal behavior; however, mBJ-LDA predicts Co₂VIn alloy to be a half metal. The band structure obtained with mBJ-LDA has an indirect band gap along the Γ–X symmetry with energy of 0.4 eV for Co₂VIn, and E _F lies in the middle of the gap; the electrons at the Fermi level are fully spin-polarized. The calculation of elastic properties indicates the stability of these compounds, and they have a ductile behavior. The 3D dependences of Young’s modulus exhibit a strong anisotropic character. The high values of the elastic constant C ₁₁ reflect the strength of the bonding Ti (V)–In.     

Evaluation using online support-vector-machines and fuzzy reasoning. Application to condition monitoring of speeds rolling process

A method for process condition monitoring and evaluation, which combines the online support vector machine (SVM) regression and the fuzzy sets methods, is proposed. To account for the time dependence, the proposed approach is based on moving windows in order to take into account the past and new data for the model’s adaptation. The fuzzy analysis is then applied to the generated residual data to give an evaluation of the condition monitoring. The proposed approach is applied to hot rolling for constructing a complementary condition monitoring system, which permits an online quality evaluation in the rolling process. Simulation results based on residual data show that the new approach is easily implementable.     

Architectures for Cooperative Airborne Simultaneous Localisation and Mapping

This paper develops active Simultaneous Localisation And Mapping (SLAM) trajectory control strategies for multiple cooperating Unmanned Aerial Vehicles (UAVs) for tasks such as surveillance and picture compilation in Global Positioning System (GPS)-denied environments. Each UAV in the team uses inertial sensor and terrain sensor information to simultaneously localise the UAV while building a point feature map of the surrounding terrain, where map information is shared between vehicles over a data fusion network. Multi-vehicle active SLAM control architectures are proposed that actively plan the trajectories and motions of each of the vehicles in the team based on maximising information in the localisation and mapping estimates. We demonstrate and compare an ideal, centralised architecture, where a central planning node chooses optimal actions for each UAV, and a coordinated, decentralised architecture, where UAVs make their own control decisions based on common shared map information. The different architectures involve varying degrees of complexity and optimality through differing communications and computational requirements. Results are presented using a three-UAV team in a six-degree of freedom multi-UAV simulator.