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The challenges on carbon nanotubes and graphene are still the subject of many research works due to its unique properties. There are three main methods to synthesis carbon nanotubes in which chemical vapor deposition (CVD) method can use for large scale production. The principle of CVD is the decomposition of various hydrocarbons over transition metal supported catalyst. KIT-6 molecular sieve was used as a support to prepare cobalt catalyst for CVD method using metal impregnation method to produce cobalt loadings of 2, 4 and 6 wt%. The catalysts were characterized by XRD, FTIR &TEM. Carbon nanotubes (CNTs) synthesized on Co-KIT-6 was also characterized by XRD, TGA, SEM & Raman spectra. Graphene was synthesized by Hummers method, which is the most common method for preparing graphene oxide. Graphene oxide was prepared by oxidation of graphite using some oxidizing agents like sulphuric acid, sodium nitrate and potassium permanganate. This graphene oxide is further treated with hydrazine solution to convert it into chemically converted graphene and also decorated with nickel metal and characterized. Hummer’s method is important for large scale production of graphene. Both Graphene and carbon nanotubes are used in different fields due to its unique properties. Both Graphene and carbon nanotubes are fabricated in counter electrode of Dye sensitized solar cells (DSSC). By cyclic voltammetry study, it confirms that both materials are good and efficient to replace platinum in the DSSC.

Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2014 (ICNAAM-2014), 22–28 September 2014 Location: Rhodes, Greece ISBN 978-0-7354-1287-3 In the present paper the Flamelet-Generated Manifold (FGM) chemistry reduction method is implemented and extended for the inclusion of all the features that are typically observed in stationary gas-turbine combustion. These consist of stratification effects, heat loss and turbulence. The latter is included by coupling FGM with the Reynolds Averaged Navier Stokes(RANS)model. Three control variables are included for the chemistry representation: the reaction evolution is described by the reaction progress variable, the heat loss is described by the enthalpy and the stratification effect is expressed by the mixture fraction. The interaction between chemistry and turbulence is considered through a presumed probability density function (PDF) approach, which is considered for progress variable and mixture fraction. This results in two extra control variables: progress variable variance and mixture fraction variance. The resulting manifold is five-dimensional, in which the dimensions are progress variable, enthalpy, mixture fraction, progress variable variance and mixture fraction variance. In addition, a highly turbulent and swirling flame in a gas turbine model combustor is computed, in order to test the 5-D FGM implementation. The use of FGM as a combustionmodel shows that combustion features at gas turbine conditions can be satisfactorily reproduced with a reasonable computational effort. The implemented combustionmodel retains most of the physical accuracy of a detailed simulation while drastically reducing its computational time, paving the way for new developments of alternative fuel usage in a cleaner and more efficient combustion. In the present paper the Flamelet-Generated Manifold (FGM) chemistry reduction method is implemented and extended for the inclusion of all the features that are typically observed in stationary gas-turbine combustion. These consist of stratification effects, heat loss and turbulence. The latter is included by coupling FGM with the Reynolds Averaged Navier Stokes(RANS)model. Three control variables are included for the chemistry representation: the reaction evolution is described by the reaction progress variable, the heat loss is described by the enthalpy and the stratification effect is expressed by the mixture fraction. The interaction between chemistry and turbulence is considered through a presumed probability density function (PDF) approach, which is considered for progress variable and mixture fraction. This results in two extra control variables: progress variable variance and mixture fraction variance. The resulting manifold is five-dimensional, in which the dimensions are progress variable, enthalpy, mixture fraction, progress variable variance and mixture fraction variance. In addition, a highly turbulent and swirling flame in a gas turbine model combustor is computed, in order to test the 5-D FGM implementation. The use of FGM as a combustionmodel shows that combustion features at gas turbine conditions can be satisfactorily reproduced with a reasonable computational effort. The implemented combustionmodel retains most of the physical accuracy of a detailed simulation while drastically reducing its computational time, paving the way for new developments of alternative fuel usage in a cleaner and more efficient combustion.

Over the past few years, significant growth has been observed in using MEMS based passive components in the RF microelectronics domain, especially in transceiver system. This is due to some excellent properties of the MEMS devices like low loss, low cost and excellent isolation. This paper presents a design of high performance MEMS passive band pass filter, consisting of L and C with improved quality factor and insertion loss less than the reported filters. In this paper we have presented a design of 2nd order band pass filter with 2.4GHz centre frequency and 83MHz bandwidth for Bluetooth application. The simulation results showed improved Q-factor of 34 and Insertion loss of 1.7dB to 1.9dB. The simulation results needs to be validated by fabricating the device, fabrication flow of which is also presented in the paper.

In the present paper a novel functionally graded piezoelectric (FGP) actuated Poly-Si micro cantilever probe is proposed for atomic force microscope. The shear piezoelectric coefficient d15 has much higher value than coupling coefficients d31 and d33, hence in the present work the micro cantilever beam actuated by d15 effect is utilized. The material properties are graded in the thickness direction of actuator by a simple power law. A three dimensional finite element analysis has been performed using COMSOL Multiphysics® (version 4.2) software. Tip deflection and free vibration analysis for the micro cantilever probe has been done. The results presented in the paper shall be useful in the design of micro cantilever probe and their subsequent utilization in atomic force microscopes.

In this paper three types of carbon nanotubes, namely, zigzag (n, 0), armchair (n= m), and chiral (n, m) are investigated with and without doping using simulation technique. The electronic properties like band structure and density of states of these three configurations with different values of n and m vectors are analysed and compared using Atomistix Toolkit (ATK) software. When the band structures of the designed configurations, reported in this paper are compared, it is observed that when the value of (n-m) vector is divisible by three, the CNTs behave as metals, otherwise they behave as semiconductors. The density of states of carbon nanotubes depicts the energy gap around the Fermi level. For the tube with chiral chirality, density of states is zero near the Fermi level, for semiconductor behaviour there is small gap in density of states near Fermi level and gap increases as the behaviour changes to insulator.

FBAR (Thin Film Bulk Acoustic Wave Resonator) devices are commonly used as application of RF (Radio Frequency) filters for the cell phones and other communication devices. This paper reports about the measurement of the efficiency of FBAR devices. The efficiency is commonly measured in terms of the EMCC (Electromechanical coupling coefficient) and QF (Quality factor). Since the FBAR devices are designed in many shapes and sizes which depend on their working frequency range. So every shape and size has a different value of QF and EMCC. This paper compares the various shapes in terms of QF, EMCC and spurious modes of L-Band (1-2 GHz) resonator. Once the best shape is selected, the study of different metal electrode materials coupling with piezoelectric layer and the effect of the thickness ratio (td) of electrode layer and the piezoelectric layer is discussed.

The preliminary assessment of a Lower Hybrid Current Drive (LHCD) system for the DEMOnstration power plant (DEMO) is mainly focused on the R&D needs of the less conventional RF components of the Main Transmission Line (MTL) and of the launcher. 500 kW, CW klystrons will be used to deliver the RF power to independent Passive Active Multijunction (PAM) launcher modules at 5 GHz. This paper describes the criteria followed to investigate the optimum solution for the RF window used as vacuum barrier between the MTL and the launcher, an open issue in the LHCD system for ITER too. The best candidate, capable of withstanding a power level of, or above, 0.5 MW in CW operation and to satisfy the electrical and thermonuclear requirements, is a Pill-Box assembly, based on a thin single disk of CVD-diamond as dielectric, water cooled at the edge. A thickness of 3 mm, much shorter than half a wavelength of the TE°11 mode in the dielectric as in the conventional window (unfeasible and too expensive with CVD-diamond at these frequencies), is sufficient to limit the exerted stress at the edge under the fracture stress for a maximum pressure applied of 0.9 MPa. In this paper the simulation results of conventional and thin CVD-diamond vacuum windows are presented comparing S-parameters, losses and electric fields in both matching condition and with VSWR = 2, using WR284 and WR229 as input/output rectangular waveguide. © 2014 American Institute of Physics.

Tore Supra is dedicated to long pulse operation at high power, with a record in injected energy of 1 GJ (2.8 MW × 380 s) and an achieved capability of 12 MW injected power delivered by 3 RF systems: Lower Hybrid Current Drive (LHCD), Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH). The new WEST project (W [tungsten] Environment in Steady-state Tokamak) aims at fitting Tore Supra with an actively cooled tungsten coated wall and a bulk tungsten divertor. This new device will offer to ITER a test bed for validating the relevant technologies for actively cooled metallic components, with D-shaped H-mode plasmas. For WEST operation, different scenarii able to reproduce ITER relevant conditions in terms of steady state heat loads have been identified, ranging from a high RF power scenario (15 MW, 30 s) to a high fluence scenario (10 MW, 1000 s). This paper will focus on the evolution of the RF systems required for WEST. For the ICRH system, the main issues are its ELM resilience and its CW compatibility, three new actively cooled antennas are being designed, with the aim of reducing their sensitivity to the load variations induced by ELMs. The LH system has been recently upgraded with new klystrons and the PAM antenna, the possible reshaping of the antenna mouths is presently studied for matching with the magnetic field line in the WEST configuration. For the ECRH system, the device for the poloidal movement of the mirrors of the antenna is being changed for higher accuracy and speed.Tore Supra is dedicated to long pulse operation at high power, with a record in injected energy of 1 GJ (2.8 MW × 380 s) and an achieved capability of 12 MW injected power delivered by 3 RF systems: Lower Hybrid Current Drive (LHCD), Ion Cyclotron Resonance Heating (ICRH) and Electron Cyclotron Resonance Heating (ECRH). The new WEST project (W [tungsten] Environment in Steady-state Tokamak) aims at fitting Tore Supra with an actively cooled tungsten coated wall and a bulk tungsten divertor. This new device will offer to ITER a test bed for validating the relevant technologies for actively cooled metallic components, with D-shaped H-mode plasmas. For WEST operation, different scenarii able to reproduce ITER relevant conditions in terms of steady state heat loads have been identified, ranging from a high RF power scenario (15 MW, 30 s) to a high fluence scenario (10 MW, 1000 s). This paper will focus on the evolution of the RF systems required for WEST. For the ICRH system, the main issues are its ELM resil...

This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

The paper addresses new variants of the high pressure resin transfer molding (HP-RTM) process namely high pressure injection RTM (HP-IRTM) and high pressure compression RTM (HP-CRTM) for manufacturing of carbon fiber reinforced composites with high fiber volume content. Both these processes utilize high-pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The paper addresses results of a study which investigated cavity pressure measurement for both the HP-RTM process variants using a specially designed highpressure RTM mold. The investigations indicate that the cavity pressure built up is a characteristic of the selected process variant. Further the relationship between the applied press force and the cavity pressure in HP-CRTM process was studied.

Since the Chinese anti-missile test in 2007 the problem of space debris and their threat to all space assets has become known to a larger community. Today, advances in laser sources and large mirrors including adaptive optics have matured and are in principle available. The paper first addresses the current situation of accumulated space debris and future predictions of collisions in space. Second, different solutions to mitigate the debris problem will be reviewed with emphasis on the use of high power pulsed lasers as derived from fundamental relations governing the momentum imparted to the debris by the laser pulse and causing their re-entry into the atmosphere with subsequent burn up. Unfortunately the required laser specifications lead to a demand of laser sources which cannot be satisfied with currently available devices. Therefore, two novel laser architectures will be presented. Finally, operational concepts and safety aspects will be addressed in order to evaluate the prospects of laser debris removal.Since the Chinese anti-missile test in 2007 the problem of space debris and their threat to all space assets has become known to a larger community. Today, advances in laser sources and large mirrors including adaptive optics have matured and are in principle available. The paper first addresses the current situation of accumulated space debris and future predictions of collisions in space. Second, different solutions to mitigate the debris problem will be reviewed with emphasis on the use of high power pulsed lasers as derived from fundamental relations governing the momentum imparted to the debris by the laser pulse and causing their re-entry into the atmosphere with subsequent burn up. Unfortunately the required laser specifications lead to a demand of laser sources which cannot be satisfied with currently available devices. Therefore, two novel laser architectures will be presented. Finally, operational concepts and safety aspects will be addressed in order to evaluate the prospects of laser debris re...

The significant drop of the storage modulus under uniaxial deformation (Payne effect) restrains the performance of the elastomer-based composites and the development of possible new applications. In this paper molecular-dynamics (MD) computer simulations using LAMMPS MD package have been performed to study the mechanical properties of a coarse-grained model of this family of nanocomposite materials. Our goal is to provide simulational insights into the viscoelastic properties of filled elastomers, and try to connect the macroscopic mechanics with composite microstructure, the strength of the polymer-filler interactions and the polymer mobility at different scales. To this end we simulate random copolymer films capped between two infinite solid (filler aggregate) walls. We systematically vary the strength of the polymer-substrate adhesion interactions, degree of polymer confinement (film thickness), polymer crosslinking density, and study their influence on the equilibrium and non-equilibrium structure, segmental dynamics, and the mechanical properties of the simulated systems. The glass-transition temperature increases once the mesh size became smaller than the chain radius of gyration; otherwise it remained invariant to mesh-size variations. This increase in the glass-transition temperature was accompanied by a monotonic slowing-down of segmental dynamics on all studied length scales. This observation is attributed to the correspondingly decreased width of the bulk density layer that was obtained in films whose thickness was larger than the end-to-end distance of the bulk polymer chains. To test this hypothesis additional simulations were performed in which the crystalline walls were replaced with amorphous or rough walls.

In‐line heat treatment of rolled materials is becoming increasingly used at hot rolling plants. The advantage of this method is the achievement of required material structure without the necessity of reheating.This paper describes a design procedure for cooling sections for the purpose of obtaining the required structure and mechanical properties. The procedure is typically used for the cooling of tubes, rails, long products and plates.Microstructure and nature of grains, grain size and composition determine the overall mechanical behaviour of steel. Heat treatment provides an efficient way to manipulate the properties of steel by controlling the cooling rate. The rate of cooling is defined by a heat transfer coefficient (HTC). Good controllability of HTC can be reached using either air‐water or water nozzles. Thus, an on‐line heat treatment with the assistance of spray nozzles enables a manufacturing process that can improve product performance by increasing steel strength, hardness and other desirable characteristics. These techniques also allow selective hardening, such that selective areas of a single object can be subjected to different treatments.An experimental stand designed for the study of cooling steel samples has been built at the Brno University of Technology. The stand comprises a movable trolley containing a test sample which moves under the spray at a given velocity. Sensors indicate the temperature history of the tested material. This experimental stand enables simulation of a variety of cooling regimes and evaluates the final structure of tested samples. The same experimental stand is also a tool for use in the design of cooling sections in order to find the required heat treatment procedure and final structure. Examples of the cooling of rails and tubes are given in the paper.

A conceptual model of integrating the sensor network and the radiative heat transfer equation is developed and presented in this paper. The idea is to present possible deployment of sensor networks in the Ethylene furnace so that valuable input in the form of boundary value can be generated in order to produce intensity distribution and heat flux distribution. Once the location of sensor deployment has been recommended, the mesh at the physical space between the furnace wall and the reactor tube is constructed. The paper concentrates only at 2D model with only 1 U‐bend reactor tube in the ethylene furnace as an initial phase of constructing a complete simulation in real furnace design.

The paper aims to investigate the classification problem of 5th dimensional complex filiform Leibniz algebras. There are two sources to get classification of filiform Leibniz algebras. The first of them is the naturally graded non‐Lie filiform Leibniz algebras and another one is the naturally graded filiform Lie algebras. Here we consider Leibniz algebras appearing both sources. It is known that this class in its turn can be split into three subclasses, first and second classes are non‐Lie filiform Leibniz algebras while the third class include the filiform Lie algebra. However, isomorphisms within each class were not investigated there. In this paper we propose an approach to the isomorphism problem in terms of invariants. Using this approach we give the complete classification of one of the above mentioned of complex filiform Leibniz algebras in 5th dimension.

The property of “reverse order law” related to generalized inverses of a matrix product AB, is the property (AB)− = B−A− for some A−, B− and (AB)− generalized inverses of A, B and AB respectively. When this property holds for all generalized inverses of them, which means that it is invariant under generalized inverses, we call this “reverse order property invariance”. In this paper we will investigate certain invariance properties of the product AB−C for studing some equivalent conditions for the reverse order property invariance. The references of Y. Tian will be the basic idea of the proofs throughout the paper.

This paper is the continuation of our work of 2008 concerning the open clusters (OCs) in system of the radio loops I–IV. In the present paper we have studied the location of OCs in relation to the Local Bubble, the Eridanus Superbubble and the Gum Nebula. As before, extremely low density of OCs from Kharchenko et al. and Dias et al. catalogs in the areas of the superbubbles (SBs) is shown. At the same time, the number of OCs in the shells exceeds several times the expected number with uniform distribution within the radius of 600 pc around the Sun. Moreover, they form rather compact groups. LSR velocities of OCs are directed away from the shells and on a tangent to them. These facts can be attributed to a common process of formation of the shells and groups of OCs. The catalog age of some OCs approximately coincides with the time of passing of the bubble radius by OC and with the time of formation of elongated compact groups of OCs. Other aspects of the problem of joint studying of OCs and SBs are noted.

In this paper we want to discuss the status of Astroparticle Physics, which is now in its golden age. Astroparticle physics—the new branch of physics born roughly at the end of the 1980‐ies—takes into account results obtained from the observations of cosmic sources via photonic experiments and particle experiments, and try to detect their global behaviour in order to understand the physical processes giving rise to them. All this for a better knowledge of the physics governing the whole Universe. Because of a limited length of the paper we will discuss only a selection of arguments, which are biased by our knowledge, as follows: 1. Introduction 2. Few Remarkable Notes 3. Background in the Universe 4. A Round‐the‐Universe Cruise 5. Prospects Conclusions

The Broyden family method for unconstrained optimization is known as one of the most efficient method in solving unconstrained optimization problem. Step size and search direction play the most important role to the convergence of the Broyden family method. Step size is proved to be successful method to solve the problem; however, it is definite to solve some complicated optimization problems. In this paper, we introduced the alternative procedure in determining the step size. This alternative procedure will be applied in the hybrid Broyden method. The numerical results based on number of iterations, number of gradient evaluation and number of function evaluation are given at the end of the paper.

In this paper we have investigated some old issues concerning four color map problem. We have given a general method for constructing counter-examples to Kempe's proof of the four color theorem and then show that all counterexamples can be rule out by re-constructing special 2-colored two paths decomposition in the form of a double-spiral chain of the maximal planar graph. In the second part of the paper we have given an algorithmic proof of the four color theorem which is based only on the coloring faces (regions) of a cubic planar maps. Our algorithmic proof has been given in three steps. The first two steps are the maximal mono-chromatic and then maximal dichromatic coloring of the faces in such a way that the resulting uncolored (white) regions of the incomplete two-colored map induce no odd-cycles so that in the (final) third step four coloring of the map has been obtained almost trivially., Comment: 27 pages, 18 figures, revised version

The paper illustrates the new features of the line‐by‐line radiative transfer model σIASI. The new features are mainly based on the computational optimization of the code and its parallelization. The paper also presents and discusses retrieval for temperature, water vapor and ozone profiles from spectra measured by the Infrared Atmospheric Sounding Interferometer in the tropical belt. Comparison with the ECMWF analysis is also provided, which shows the good quality and accuracy of IASI retrieval products.

Many aging pipelines and aircraft are suffering from corrosion and the corrosion patches are often inaccessible. There is therefore a need for a rapid, accurate, long range inspection technique to measure the remaining thickness in corrosion patches. Low‐frequency guided wave tomography is a potentially attractive technique to rapidly evaluate the thickness of large sections of partially accessible structures. This paper demonstrates that in the low‐frequency regime the ray theory may not be valid which compromises the use of any straight‐ray tomography algorithm. This paper also shows, in simulations and experimentally, that the same frequency regime can be used to successfully reconstruct thickness reduction in plates with diffraction tomography.

In this paper, results from the partition of downward surface solar radiation between direct and diffuse components under distinct aerosol loadings will be presented. The field experiment was conducted during 2007 dry season in the Reserva Biologica do Jaru, located in the Southwestern portion of the Amazon Basin (−10.145°, −61.908°), in a region with tropical rainforest vegetation. A Multi‐Filter Rotating Shadow‐band Radiometer (MFRSR) was used to measure global and diffuse components of solar radiation in narrow bands (centered at 415, 670, 870 and 1036 nm) as well as broadband (from about 350 to 1100 nm) spectral regions. Due to biomass burning emissions, high values of aerosol optical depth were observed (accompanying paper by Rosario et al., 2008). Consequently, a significant increase in diffuse solar irradiance was also observed. For example, at channel around 670 nm, the diffuse fraction corresponded to about 80%, even at noon, for aerosol optical depth of about 2 at the same wavelength, which is e...

This paper investigates the mechanics of a gigahertz oscillator comprising a nanotube oscillating within the centre of a uniform concentric ring or bundle of nanotubes. The study is also extended to the oscillation of a fullerene inside a nanotube bundle. In particular, certain fullerene‐nanotube bundle oscillators are studied, namely C60‐carbon nanotube bundle, C60‐boron nitride nanotube bundle, B36N36‐carbon nanotube bundle and B36N36‐boron nitride nanotube bundle. Using the Lennard‐Jones potential and the continuum approach, we obtain a relation between the bundle radius and the radii of the nanotubes forming the bundle, as well as the optimum bundle size which gives rise to the maximum oscillatory frequency for both the fullerene and the nanotube bundle oscillators. While previous studies in this area have been undertaken through molecular dynamics simulations, this paper emphasizes the use of applied mathematical modelling techniques which provides considerable insight into the underlying mechanisms....

This paper discusses the formulation and implementation of an acceleration approach for the MCScene code, a high fidelity model for full optical spectrum (UV to LWIR) hyperspectral image (HSI) simulation. The MCScene simulation is based on a Direct Simulation Monte Carlo approach for modeling 3D atmospheric radiative transport, as well as spatially inhomogeneous surfaces including surface BRDF effects. The model includes treatment of land and ocean surfaces, 3D terrain, 3D surface objects, and effects of finite clouds with surface shadowing. This paper will review an acceleration algorithm that exploits spectral redundancies in hyperspectral images. In this algorithm, the full scene is determined for a subset of spectral channels, and then this multispectral scene is unmixed into spectral end members and end member abundance maps. Next, pure end member pixels are determined at their full hyperspectral resolution, and the full hyperspectral scene is reconstructed from the hyperspectral end member spectra and the multispectral abundance maps. This algorithm effectively performs a hyperspectral simulation while requiring only the computational time of a multispectral simulation. The acceleration algorithm will be demonstrated, and errors associated with the algorithm will be analyzed.

CEILAP’s Lidar Division has established an atmospheric remote sensing site in Rio Gallegos (51°55′ S, 69°14′ W) in the southern region of Argentina. SOLAR Campaign was held during 2005–2006. The main objectives of this experiment were to measure stratospheric ozone profiles and surface UV radiation in a subpolar region, where the influence of polar vortex and the Antarctic ozone hole are remarkable. This remote sensing site has lidar instruments and passive sensors to measure solar UV irradiance. In this paper we focused on passive remote sensing sensors and the Rio Gallegos erythemal irradiances reported during 2005–2006. Time evolution of UV index was derived from these measurements and the influence of ozone depleted air masses passing over over Rio Gallegos is highlighted in this paper. This Patagonian region is characterized by high cloud cover during the day that strongly changes the distribution of UV radiation that reaches the ground surface. For that reason some overpasses of ozone hole are maske...

The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real‐time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real‐time DR system is capable of generating sufficient digital X‐ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D‐CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D‐CT images generated.

Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser confocal microscopy and micro‐CT were employed to characterize the structure of porous scaffolds. In order to evaluate the flow field distribution inside the micro‐structured 3D scaffolds, a computer reconstructing method based on Micro‐CT was proposed. According to this evaluating method, a contrast between 3D porous scaffolds with and without predefined internal channels was also performed to assess scaffolds’ fluid characters. Results showed that the internal channel of the 3D scaffolds formed the 3D fluid channel network; the uniformity of flow field distribution of the scaffolds fabricated in this paper was better than the simple porous scaffold without micro‐fluid channels.Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser confocal microscopy and micro‐CT were employed to characterize the structure of porous scaffolds. In order to evaluate the flow field distribution inside the micro‐structured 3D scaffolds, a computer reconstructing method based on Micro‐CT was proposed. According to this evaluating method, a contrast between 3D porous scaffolds with and without predefined internal channels was also performed to assess scaffolds’ fluid characters. Results showed that the internal channel of the 3D scaffolds formed the 3D fluid channel network; the uniformity of flow field distribution of the scaffolds fabricated in this paper was better than the simple porous scaffold without micro‐...

The paper studies the prediction of the crack growth of the brittle and ductile fracture of the structural materials. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the exponential traction separation law and on the cohesive zone modelling. Determination of micro‐mechanical parameters is based on the combination of static tests, microscopic observation and numerical calibration procedures. The attention is paid on the influence of initial value of J‐integral and the slope of R curve which is modelled by 3D FEM. The aim of this paper can be seen in verification of the application of the cohesive model based on the separation law, experimental and calibration procedure inevitable for the determination of the cohesive parameters for the modelling.

This paper deals with the construction of numerical methods of random initial value problems. Random linear multistep methods are presented and sufficient conditions for their mean square convergence are established. Main statistical properties of the approximations processes are computed in several illustrative examples. Copyright © 2010 John Wiley & Sons, Ltd., Thanks to the anonymous reviewer whose comments greatly enhanced the paper. This work has been partially supported by the Spanish M.E.C. and FEDER grants MTM2009-08587 and TRA2007-68006-C02-02, the Universidad Politecnica de Valencia grant PAID-06-09 (ref. 2588) and Mexican Conacyt.

In this paper we deal with the simulation of rigid bodies. Rigid body dynamics have become very important for simulating rigid body motion in interactive applications, such as computer games or virtual reality. We present a novel way of computing contact forces using a Newton method. The contact problem is reformulated as a system of non‐linear and non‐smooth equations, and we solve this system using a non‐smooth version of Newton’s method. One of the main contribution of this paper is the reformulation of the complementarity problems, used to model impacts, as a system of equations that can be solved using traditional methods.

This paper presents the analytical solutions and symbolic computations for the temperature distribution of the annular fin under fully‐wet surface condition. During the process of dehumidification, the annular fin is separated into two regions. The mathematical models for each region are based on the conservation of energy principle. An assumption used in this paper is the humidity ratio of the saturated air on the wet surface varies linearly with the local fin temperature. The mathematical models are solved by the Cauchy‐Euler Equation and modified Bessel Equation to form analytical solutions. Besides, the symbolic computations are shown by the Maple software to visualize the temperature distribution along the fin.

The paper deals with the numerical solution of the nonlinear wave equation. The problem is solved by combining two methods—the generalized α‐method for time discretization and the finite element method for space discretization. The nonlinear system of algebraic equations resulted from the corresponding discretization is solved by the Newton method. Newton’s method shows fast convergence and takes several iterations in each time step. The aim of the paper is to study how the use of the fixed point iteration method, instead of Newton’s method, influences the performance of finding numerical solution. As it can be concluded from the obtained results, both methods are comparable in terms of iterations while the run time of Newton’s method is higher since it requires calculating the jacobian in each time step.

In the recent papers [8], [2], and [9] three numerical methods preserving some properties of the analytical solution of a linear stochastic oscillator have been proposed. In this paper we study further properties of these schemes and confirm experimentally the conclusions.

An aspect of recent developments in computational methods for control of fluids is the design of reduced‐order controllers, for reducing the CPU costs of flow solves. In this paper a reduced order approach will be introduced for the optimal boundary control problem governed by the unsteady Navier Stokes equations with the help of the Galerkin proper orthogonal decomposition(POD) method. The paper summarizes the results of the diploma‐thesis [1].The Galerkin Proper orthogonal decomposition ([2], [3], [4], [5], [6]) provides a method for deriving reduced order models of dynamical systems. It’s based on projecting the dynamical system onto subspaces of snapshots ensemble, which is composed of the solutions for the physical system at pre‐specified time instances or experimental measurements. These snapshots are not suitable as the basis for the ensemble spanned by themselves by reason of the possible linear dependence. We will find the orthogonal basis for the ensemble by solving an eigenvalue problem, and th...

With exponential type, a class of alternating group finite difference scheme based on the saul’yev asymmetric schemes is derived for solving convection‐diffusion equation in this paper. The scheme has the obvious property of Parallelism. The result of stability analysis shows that the scheme is unconditionally stable. In the end of the paper, numerical experiment is given, which illustrates the scheme presented is of high accuracy.

We report on an investigation into stellar evolution and nucleosynthesis in the low and extremely low metallicity regime, including models of stars with a pure Big Bang composition (i.e. Z=0). The metallicity range of the extremely metal poor (EMP) models we have calculated is -6.5 < [Fe/H] < -3.0, whilst our models are in the mass range 0.85 < M < 3.0 Msun. Many of the EMP and Z=0 models experience violent evolutionary episodes not seen at higher metallicities. We refer to these events as `Dual Flashes' since they are characterised by peaks in the hydrogen and helium burning luminosities occurring at roughly the same time. Some of the material processed by these events is later dredged up by the convective envelope, causing signifcant surface pollution. These events have been reported by previous studies, so our results reaffirm their occurrence -- at least in 1D stellar models. The novelty of this study is that we have calculated the entire evolution of the Z=0 and EMP models, from the ZAMS to the end of the TPAGB, including detailed nucleosynthesis. We have also calculated the nucleosynthetic yields, which will soon be available in electronic format. Although subject to many uncertainties these are, as far as we are aware, the only yields available in this mass and metallicity range. In this paper we briefy describe some of the results in the context of abundance observations of EMP halo stars. This work formed part of SWC's PhD thesis (completed in March 2007) and a series of subsequent papers will describe the results of the study in more detail., 5 pages, 6 figures. To appear in conference proceedings "First Stars III", ed. B. O'Shea, A. Heger & T.Abel

A fundamental understanding of the effect of a surface on the resonance frequency of bubbles will be useful in the future development of diagnostic medical ultrasound equipment. In this paper we look at wall effects on the nonlinear resonance frequency response of air bubbles in water, continuing from an earlier paper which dealt with the linear response (E. M. B. Payne, S. Illesinghe, A. Ooi, and R. Manasseh, J. Acoust. Soc. Am. 118, 2841–2849 (2005)). Numerical results for micron‐sized bubbles near a rigid boundary are presented, showing a shift in frequency due to the boundary, and nearby bubbles, and a significant reduction in the amplitude of oscillations at resonance. Time delay effects are also included, which show a damping of the frequency response. Simulations are limited to the case where all bubbles oscillate in phase. An experimental method for measuring the resonance response of an air bubble attached to a surface is also outlined.

In this paper, we describe a variant of a solution for a common problem in applied statistics—we offer a variant method for estimating the parameters of a dynamic system, and observe its magnitudes, which statistically depend on the sequence of states of the system that are not observed. The method is realized by means of the multipolynomial approximations algorithm (the MPA algorithm). The method is validated by applying it to a problem of correction of finite sets of nominal experimental data on which nominal functions are constructed equationsby means of interpolation from the current states of the system. Nominal experimental data are presented on a finite set of points covering the domains of definition of the nominal functions. The nominal equations of motion of the dynamical system are defined by the nominal functions. In this paper, the concrete example of the nominal equations of motion correspond to the longitudinal motion of the aircraft similar of the F‐l6 aircraft. The nominal functions are t...

This paper deals with a class of special primes called safe primes. In the regular definition, an odd prime p is safe if, at least, one of (p±1)/2 is prime. Safe primes have been recommended as factors of RSA moduli. In this paper, the concept of safe primes is extended to higher‐order safe primes, and an explicit formula to compute the density of this class of primes in the set of the integers is supplied. Finally, explicit conditions are provided permitting the algorithmic computation of safe primes of arbitrary order. Some experimental results are provided as well.

In a recent working paper, [1] make a comprehensive proposal putting forward robust, heavy‐tailed priors over conjugate, light‐tailed priors in Bayesian analysis. The paper focuses particularly on clinical trials, where information from previous trials should be used in an non‐dogmatic fashion, suggesting the use of robust priors. Robust priors have bounded influence in the posterior distribution and their influence is inversely related to the conflict between the data in previous and the current trial. Clearly, the likelihood has to be taken into consideration and not only the prior. We explore here a novel proposal based on a cross‐entropy measure of comparison between different models, on which the expectations of the log ratio of the evidences of the contender models are taken with respect to each of the different models and then compared. We also compute the expected increase of information within each model. Both criteria seems to justify the use of robust priors.

The purpose of the paper is to underline the trends of space physics, illustrated with several missions which are to day operating or that will are scheduled in the next future. A first set of sections is devoted to fundamental sciences with the analysis of the interaction between the solar wind and the planets and to planetary exploration. Emphasis is put on the mass and energy transfer between the solar wind and the Earth magnetosphere, and to what has been learned from the multi‐spacecraft CLUSTER mission. Then the scientific objectives and the instrumentation of the CASSINI/Huygens mission to Saturn are presented. Turning to Mars and to mercury, several aspects of missions to these planets are outlined. They include the study of the interaction of the solar wind with planetary magnetic environment (Mercury), its interaction with the upper atmosphere and ionosphere (Mars), the electromagnetic sounding of the planetary solid crust (Mars). Finally, turning to the global solar system scale, few words are told on the study of the interaction of the heliosphere with the local interstellar cloud, through the heliopause, the frontier of the solar wind. The last section of the paper presents the consequences of space environment strong events on human activity and the emerging concept of Space Weather, with growing efforts for monitoring the solar activity, the associated changes of the terrestrial ionized environment and for preventing damages to spacecraft and ground based equipments.

Cultivator, one of the agriculture farm tool, extensively suffers from the wear problem. In this paper, we report nanostructured chromium nitrite (CrN) coating for the cultivator shovels to mitigate wear problem. The (CrN) coating was developed using DC magnetron sputtering technique at 200 °C. The structural, morphological, hydrophobic and wear properties were investigated using X-ray diffractometer, scanning electron microscope, contact angle goniometer and custom designed soil bin assembly. The XRD reveals that the deposited coating was polycrystalline in nature with cubic structure. Also, The deposited coating was found to be anti wear resistant as well as hydrophobic in nature. The gravimetric wear for the coating developed at 200 °C coated was found out to be 8.15 gm and for non coated it was 14.48 gm tested for 100 hrs. The roughness of the coating plays an important role in determining the hydrophobicity of the coated film. Roughness and contact angle measured for 200 °C coated shovel was found ou...

This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

This paper presents design and fabrication of a 1-DOF (degree-of-freedom) drive mode and 2-DOF sense mode micro-gyroscope. It is an inherently robust structure and offers a high sense frequency bandwidth. The proposed design utilizes resonance of the1-DOF drive mode oscillator and employs dynamic amplification concept in sense modes to increase the sensitivity while maintaining robustness. The 2-DOF in the sense direction renders the device immune to process imperfections and environmental effects. The design is simulated using FEA software (CoventorWare®). The device is designed considering process compatibility with SU-8 based UV-LIGA process, which is an economical fabrication technique. The complete fabrication process is presented along with SEM images of the fabricated device. The device has 9 µm thick Nickel as the key structural layer with an overall reduced key structure size of 2.2 mm by 2.1 mm.

In this paper we investigate the effect of separation of triangular metal electrodes with both convex and concave geometries, on the localization of suspended DNA molecules under the combined effect of dielectrophoresis and AC electro-osmosis through simulations using COMSOL Multiphysics. Trapping points are realized within the electrodes which are found to vary with the separation of the electrodes.

This paper proposes a methodology of finding effective elastic properties of nanoclay-reinforced polymer composites with aligned clay particles. When interphase regions exist between nanoclay platelets and polymer, numerical homogenization is initially required to identify the properties of effective particle consisting of both clay and interface regions. Once the elastic properties of equivalent particle are obtained, Mori-Tanaka approach is employed to identify all the effective properties of resultant composite. The methodology is implemented with a modular based computer program developed in MATLAB and the variation of longitudinal modulus as a function of weight fraction of nanoclay, aspect ratio of fibers, number of stacks, nanoclay volume fraction etc is reported. The empirical results are validated with a numerical model developed in ANSYS using a representative volume element for prediction of the elastic modulus. Results are illustrated with two cases of exfoliated morphology.

Graphene nano ribbons are the strips of graphene sheet which opens band gap in graphene. This opening of band gap increases the on off ratio of these GNR devices and allows its use in logic circuit applications. GNR in transistors give vital applications in these areas. A GNRFET shows large conductance with respect to gate voltages. The effect of temperature on this conductance is seen in this paper by simulating a GNRFET model in VNL. A GNRFET with zigzag electrodes and armchair channel is studied. The conductance with respect to temperature is seen. A temperature range of 0 to 2000 K is selected for the study.