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CONSPECTUS: Two-dimensional (2D) crystals derived from transition metal dichalcogenides (TMDs) are intriguing materials that offer a unique platform to study fundamental physical phenomena as well as to explore development of novel devices. Semiconducting group 6 TMDs such as MoS2 and WSe2 are known for their large optical absorption coefficient and their potential for high efficiency photovoltaics and photodetectors. Monolayer sheets of these compounds are flexible, stretchable, and soft semiconductors with a direct band gap in contrast to their well-known bulk crystals that are rigid and hard indirect gap semiconductors. Recent intense research has been motivated by the distinct electrical, optical, and mechanical properties of these TMD crystals in the ultimate thickness regime. As a semiconductor with a band gap in the visible to near-IR frequencies, these 2D MX2 materials (M = Mo, W; X = S, Se) exhibit distinct excitonic absorption and emission features. In this Account, we discuss how optical spectroscopy of these materials allows investigation of their electronic properties and the relaxation dynamics of excitons. We first discuss the basic electronic structure of 2D TMDs highlighting the key features of the dispersion relation. With the help of theoretical calculations, we further discuss how photoluminescence energy of direct and indirect excitons provide a guide to understanding the evolution of the electronic structure as a function of the number of layers. We also highlight the behavior of the two competing conduction valleys and their role in the optical processes. Intercalation of group 6 TMDs by alkali metals results in the structural phase transformation with corresponding semiconductor-to-metal transition. Monolayer TMDs obtained by intercalation-assisted exfoliation retains the metastable metallic phase. Mild annealing, however, destabilizes the metastable phase and gradually restores the original semiconducting phase. Interestingly, the semiconducting 2H phase, metallic 1T phase, and a charge-density-wave-like 1T' phase can coexist within a single crystalline monolayer sheet. We further discuss the electronic properties of the restacked films of chemically exfoliated MoS2. Finally, we focus on the strong optical absorption and related exciton relaxation in monolayer and bilayer MX2. Monolayer MX2 absorbs as much as 30% of incident photons in the blue region of the visible light despite being atomically thin. This giant absorption is attributed to nesting of the conduction and valence bands, which leads to diversion of optical conductivity. We describe how the relaxation pathway of excitons depends strongly on the excitation energy. Excitation at the band nesting region is of unique significance because it leads to relaxation of electrons and holes with opposite momentum and spontaneous formation of indirect excitons., G.E. acknowledges Singapore National Research Foundation for funding the research under NRF Research Fellowship (NRF- NRFF2011-02). G.E. also thanks the Graphene Research Centre at the National University of Singapore for funding support. R.M.R is thankful for the financial support by FEDER through the COMPETE Program, by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/UI607/2011 and Grant Nr.SFRH/BSAB/1249/2012, and by the EC under Graphene Flagship (contract no. CNECT-ICT-604391)., FEDER, COMPETE, Graphene Flagship

Aim: The aim of the study was to establish the methods for diagnosis various canine cardiac ailments using echocardiography. Materials and Methods: M-mode, two-dimensional echocardiography and Doppler studies were performed on 10 cases. Dogs showing signs of cardiac ailment either clinically, radiographic or via electrocardiographic examination were selected for study. Right parasternal short axis view was used for echocardiographic measurements. Right parasternal long axis and left parasternal apical views were used for Doppler studies. Doppler studies were performed at the level of aortic valve and atrioventricular valves for semi quantitative diagnosis of regurgitation. Results: Dogs were found affected with dilated cardiomyopathy (DCM) (n=5), pericardial effusion (PE) (n=1), combined PE and DCM (n=2) and remaining two showed abnormality on radiographic or electrographically evaluation but were found out to be normal echocardiographically (n=2). Conclusion: Echocardiography is an effective tool for diagnosis of various heart ailments.

In this paper we present computational cost estimates for parallel shared memory isogeometric multi-frontal solvers. The estimates show that the ideal isogeometric shared memory parallel direct solver scales as O ( p 2 log ( N / p ) ) for one dimensional problems, O ( N p 2 ) for two dimensional problems, and O ( N 4 / 3 p 2 ) for three dimensional problems, where N is the number of degrees of freedom, and p is the polynomial order of approximation. The computational costs of the shared memory parallel isogeometric direct solver are compared with those corresponding to the sequential isogeometric direct solver, being the latest equal to O ( N p 2 ) for the one dimensional case, O ( N 1.5 p 3 ) for the two dimensional case, and O ( N 2 p 3 ) for the three dimensional case. The shared memory version significantly reduces both the scalability in terms of N and p . Theoretical estimates are compared with numerical experiments performed with linear, quadratic, cubic, quartic, and quintic B-splines, in one and two spatial dimensions.

We consider the numerical approximation of the boundary and internal thermoelastic fields in the case of two-dimensional isotropic linear thermoelastic solids by combining the method of fundamental solutions (MFS) with the method of particular solutions (MPS). A particular solution of the non-homogeneous equations of equilibrium associated with a planar isotropic linear thermoelastic material is derived from the MFS approximation of the boundary value problem for the heat conduction equation. Moreover, such a particular solution enables one to easily develop analytical solutions corresponding to any two-dimensional domain occupied by an isotropic linear thermoelastic solid. The accuracy and convergence of the proposed MFS-MPS procedure are validated by considering three numerical examples. © 2013 Elsevier Ltd. All rights reserved. 37 7-8 1004 1020 Cited By :14

ObjectiveaaThe present study assessed the difference in the brain activity of professional gamers (excessive players, but not addicts) in response to playing a 3-dimensional online game with an improved interface. MethodsaaTwenty-three StarCraft I pro gamers and 16 StarCraft II pro gamers were recruited at Chung Ang University Medical Cen ter. Brain activity in response to StarCraft I or II cues was assessed with a 1.5 Tesla Espree MRI scanner. ResultsaaStarCraft I pro gamers showed significantly greater activity in 4 clusters in response to the video game cues compared to Star Craft II pro gamers: right superior frontal gyrus, right medial frontal gyrus, right occipital lobe, and left medial frontal gyrus. StarCraft II pro gamers showed significantly greater activity in 3 clusters in response to the video game cues compared to StarCraft I pro gamers: left middle frontal gyrus, left temporal fusiform gyrus and left cerebellum. DiscussionaaThis is the first study to show the difference in brain activity between gamers playing either a 2-dimensional or 3-dimen sional online game. Current brain imaging studies may confirm the pro gamers’ experience when playing StarCraft II, a 3-dimensional game with an improved interface, relative to playing StarCraft I. Psychiatry Investig 2013;10:115-120 Key Wordsaa StarCraft, Three dimensional, Two dimensional, Pro-gamer, Functional magnetic resonance imaging.

A procedure to reconstruct two phase porous media, given the porosity and the two point correlation function of such media is described. The random media are modelled as a discrete valued random field Z(x?), which takes value 1 in regions of pores and 0 in regions of solid phase. The field Z(x?) is obtained by applying a non-linear filter - Nataf's transformation - to a correlated Gaussian random field Y(x?). The two point correlation function RYY of the Gaussian field Y is related to the two point correlation function RZZ of the field Z and can be calculated by expanding the bivariate Gaussian probability in terms of Hermite polynomials. The correlation function of the Gaussian field is decomposed into eigenfunctions and eigenvalues required by the Karhunen-L�eve expansion. The eigenfunctions and eigenvalues are used to generate as many samples of the Gaussian field as required and the discrete field corresponding to each such sample can be obtained by applying the non-linear filter mentioned above. The method was tested by generating a large number of samples of one and two dimensional Debye random media using different porosities and different correlation lengths and the statistics of the ensemble was found to agree favourably with the input data. Also one and two dimensional 'chess board' patterns were reconstructed to see how well the geometry is reconstructed. The one dimensional case was reconstructed very accurately, whereas the two dimensional case, though not very satisfactory, indicates that the method captures some of the essentials of the geometry. The method also has the advantage that it gives an analytical framework for the porous media in terms of the random fields. These random fields could be used for further studies related to porous media. � 2013 Elsevier Ltd.

The Landau quantization of the two-dimensional (2D) heavy holes, its influence on the energy spectrum of 2D magnetoexcitons, as well as their optical orientation are studied. The Hamiltonian of the heavy holes is written in two-band model taking into account the Rashba spin-orbit coupling (RSOC) with two spin projections, but with nonparabolic dispersion law and third-order chirality terms. The most Landau levels, except three with m=0,1,2, are characterized by two quantum numbers m-3 and m for m≥3 for two spin projections correspondingly. The difference between them is determined by the third-order chirality. Four lowest Landau levels (LLLs) for heavy holes were combined with two LLLs for conduction electron, which were taken the same as they were deduced by Rashba in his theory of spin-orbit coupling (SOC) based on the initial parabolic dispersion law and first-order chirality terms. As a result of these combinations eight 2D magnetoexciton states were formed. Their energy spectrum and the selection rules for the quantum transitions from the ground state of the crystal to exciton states were determined. On this base such optical orientation effects as spin polarization and magnetoexciton alignment are discussed. The continuous transformation of the shake-up (SU) into the shake-down (SD) recombination lines is explained on the base of nonmonotonous dependence of the heavy hole Landau quantization levels as a function of applied magnetic field. © 2013 Elsevier B.V. All rights reserved.

Globulins are an important group of seed storage proteins in dicotyledonous plants. They are synthesized during seed development, assembled into very compact protein complexes, and finally stored in protein storage vacuoles (PSVs). Here, we report a proteomic investigation on the native composition and structure of cruciferin, the 12 S globulin of Brassica napus. PSVs were directly purified from mature seeds by differential centrifugations. Upon analyses by blue native (BN) PAGE, two major types of cruciferin complexes of ∼ 300–390 kDa and of ∼470 kDa are resolved. Analyses by two-dimensional BN/SDS-PAGE revealed that both types of complexes are composed of several copies of the cruciferin α and β polypeptide chains, which are present in various isoforms. Protein analyses by two-dimensional isoelectric focusing (IEF)/SDS-PAGE not only revealed different α and β isoforms but also several further versions of the two polypeptide chains that most likely differ with respect to posttranslational modifications. Overall, more than 30 distinct forms of cruciferin were identified by mass spectrometry. To obtain insights into the structure of the cruciferin holocomplex, a native PSV fraction was analyzed by single particle electron microscopy. More than 20,000 images were collected, classified, and used for the calculation of detailed projection maps of the complex. In contrast to previous reports on globulin structure in other plant species, the cruciferin complex of Brassica napus has an octameric barrel-like structure, which represents a very compact building block optimized for maximal storage of amino acids within minimal space. Background: Cruciferin represents the most abundant protein in Brassica napus seeds where its efficient storage is essential under minimized space conditions. Results: The cruciferin complex has an octameric barrel-like structure of ∼420 kDa. Conclusion: The barrel-like structure represents a compact building block optimized for maximal storage of amino acids. Significance: Novel insights into structure and packing of seed storage proteins.

3D printing applications have achieved increased success as an additive manufacturing (AM) process. Micro-structure of mechanical/biological materials present design challenges owing to the resolution of 3D printers and material properties/composition. Biological materials are complex in structure and composition. Efforts have been made by 3D printer manufacturers to provide materials with varying physical, mechanical and chemical properties, to handle simple to complex applications. As 3D printing is finding more medical applications, we expect future uses in areas such as hip replacement - where smoothness of the femoral head is important to reduce friction that can cause a lot of pain to a patient. The issue of print resolution plays a vital role due to staircase effect. In some practical applications where 3D printing is intended to produce replacement parts with joints with movable parts, low resolution printing results in fused joints when the joint clearance is intended to be very small. Various 3D printers are capable of print resolutions of up to 600dpi (dots per inch) as quoted in their datasheets. Although the above quoted level of detail can satisfy the micro-structure needs of a large set of biological/mechanical models under investigation, it is important to include the ability of a 3D slicing application to check that the printer can properly produce the feature with the smallest detail in a model. A way to perform this check would be the physical measurement of printed parts and comparison to expected results. Our work includes a method for using ray casting to detect features in the 3D CAD models whose sizes are below the minimum allowed by the printer resolution. The resolution validation method is tested using a few simple and complex 3D models. Our proposed method serves two purposes: (a) to assist CAD model designers in developing models whose printability is assured. This is achieved by warning or preventing the designer when they are about to perform shape operations that will lead to regions/features with sizes lower than that of the printer resolution; (b) to validate slicing outputs before generation of G-Codes to identify regions/features with sizes lower than the printer resolution.

Semiconductors are ubiquitous gain media for coherent light sources. Solution-processed three-dimensional (3D) halide perovskites (e.g., CH3NH3PbI3) with their outstanding room temperature optical gain properties are the latest members of this family. Their two-dimensional (2D) layered perovskite counterparts with natural multiple quantum well structures exhibit strong light–matter interactions and intense excitonic luminescence. However, despite such promising traits, there have been no reports on room temperature optical gain in 2D layered perovskites. Herein, we reveal the challenges towards achieving amplified spontaneous emission (ASE) in the archetypal (C6H5C2H4NH3)2PbI4 (or PEPI) system. Temperature-dependent transient spectroscopy uncovers the dominant free exciton trapping and bound biexciton formation pathways that compete effectively with biexcitonic gain. Phenomenological rate equation modeling predicts a large biexciton ASE threshold of ∼1.4 mJ cm−2, which is beyond the damage threshold of these materials. Importantly, these findings would rationalize the difficulties in achieving optical gain in 2D perovskites and provide new insights and suggestions for overcoming these challenges. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) Published version

We consider the most general two dimensional linear parabolic equations. Motivated by the recent work of Ibragimov et al. [1-3] we construct differential invariants, semi-invariants and invariant equations. These results are achieved with the employment of the equivalence group admitted by this class of parabolic equations. We derive those variable coefficient equations of this class of linear parabolic equations that can be mapped into constant coefficient equations. Further applications are presented. © 2012 Elsevier B.V. 17 9 3673 3681 Cited By :3

In this paper, a numerical study of combined natural convection and surface radiation heat transfer in a solar trapezoidal cavity absorber for Compact Linear Fresnel Reflector (CLFR) is presented. The CFD package, FLUENT 6.3 is used to develop the 2-D, non-Boussinesq, steady state, laminar, combined natural convection and surface radiation heat transfer model for a trapezoidal cavity absorber. The validation of the present non-Boussinesq numerical procedure is compared with other closed cavity model. Based on the validated non-Boussinesq model, the combined heat loss coefficients are predicted for various parameters such as Grashof number, absorber angles, surface emissivity, aspect ratio, temperature ratio and radiation-conduction number. The numerical simulation results are presented in terms of Nusselt number correlation to show the effect of these parameters on combined natural convection and surface radiation heat loss. � 2011 Elsevier Ltd.

In this paper, a genetic and heuristic approach is proposed for nesting of multiple, two-dimensional (2D)-shaped parts in 2D-shaped sheet with the aim of minimizing the wastage of sheet material. It presents a new method that can represent the geometry of sheet and part in a fast and effective way using the concepts of analytical geometry and semi-discrete form of representation. The method proposed to obtain an optimal sequence of parts is a modified genetic algorithm that chooses pre-determined sequence of parts as initial population instead of randomly generated sequence of parts as initial population. The effect of initial population on final optimal sequence and the effectiveness of the proposed scheme of representation are examined by comparing the results obtained to those obtained with the approach proposed by Babu and Babu (2001). Both utilized semi-discrete representation scheme proposed by Ma and Liu (2007). � 2012 World Scientific Publishing Company.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:05Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:23Z : No. of bitstreams: 1 2-s2.0-80054916182.pdf: 415307 bytes, checksum: f1de55c13d0c9537402066a956d60fb5 (MD5) Made available in DSpace on 2014-05-27T11:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-15 The location of invariant tori for a two-dimensional Hamiltonian mapping exhibiting mixed phase space is discussed. The phase space of the mapping shows a large chaotic sea surrounding periodic islands and limited by a set of invariant tori. Given the mapping considered is parameterised by an exponent γ in one of the dynamical variables, a connection with the standard mapping near a transition from local to global chaos is used to estimate the position of the invariant tori limiting the size of the chaotic sea for different values of the parameter γ. © 2011 Elsevier B.V. All rights reserved. Departamento de Estatística Matemat. Apl. e ComputaoInstituto de Geociências e Ciências Exatas UNESP Univ Estadual Paulista, Av.24A, 1515Bela Vista, CEP: 13506-900 Rio Claro SP Departamento de Estatística Matemat. Apl. e ComputaoInstituto de Geociências e Ciências Exatas UNESP Univ Estadual Paulista, Av.24A, 1515Bela Vista, CEP: 13506-900 Rio Claro SP

We study a problem for two-dimensional steady potential and isentropic Euler equations in a bounded domain, where an artificial detached shock interacts with a wedge. Using the stream function, we obtain a free boundary problem for the subsonic state and the detached artificial shock curve and we prove that such configuration admits a unique solution in certain weighted Hlder spaces. The proof is based on various Hlder and Schauder estimates for second-order elliptic equations and fixed point theorems. Moreover, we pose an energy principle and remark that the physical attached shock is the minimizer of the energy functional. © 2010 Elsevier Ltd. All rights reserved. 74 3 705 720

This paper proposes a hybrid approach, wherein Markov Chain Monte Carlo (MCMC) simulations are used in a Bayesian framework, in conjunction with artificial neural networks (ANN) for solving an inverse heat conduction problem. The proposed algorithm was tested for the problem of steady state two-dimensional heat conduction from a square slab with uniform volumetric internal heat generation. Two variants of this problem namely: (a) estimation of the convection heat transfer coefficient, h and the thermal conductivity of the material, k given the rate of heat generation qv and (b) estimation of k and qv given the heat transfer coefficient h, are considered. For both the problems, temperature data at certain fixed locations in the slab serves as the input. For the purposes of establishing the soundness and efficacy of the algorithm, temperatures obtained by a numerical solution to the governing equation for known values of the parameters to be retrieved are treated as "measured" data. However, white noise was added to these data not only to make the analysis realistic but also to ascertain the robustness of the retrieval methodology. In order to significantly reduce the computational time associated with the MCMC simulations, first, a neural network was trained with limited number of solutions to the forward model. This network was used to replace the forward model (conduction equation) during the process of retrievals with Markov Chain Monte Carlo simulations in a Bayesian framework, thereby making the retrievals hybrid. The performance of the proposed hybrid technique was evaluated for different priors and various levels of noise. Comparisons with retrievals done directly by ANN revealed that the performance of the hybrid method is demonstrably superior, particularly with noisy data. � 2010 Elsevier Ltd. All rights reserved.

A finite-volume-based incompressible flow algorithm on Cartesian grid is presented for the simulation of evaporation phenomena in a falling liquid film under low wall superheat conditions. The model employs the PLIC-VOF method to capture the free surface evolution, and the continuum surface force (CSF) approximation to emulate the effects of interfacial tension. The phase change process is represented through a source term in the interfacial cells, which is evaluated from the normal temperature gradients on either side of the interface. In order to evaluate these discontinuous temperature gradients across the interface accurately, a simple and efficient ghost fluid method has been implemented, which properly takes into account the dynamic evolution of the interface. The overall numerical model, including the phase change algorithm, has been validated against standard benchmark analytical results. Finally, the model is used to simulate the evaporating flow of a 2-D laminar, developing film falling over an inclined plane surface, subjected to constant wall heat flux. The results thus obtained, clearly illustrate the significance of inertial effects in the developing region of the falling film, which are generally neglected in the available analytical models. It is also observed, that the evaporation of fluid commences only after the growing thermal boundary layer reaches the interface, and the length of the nonevaporating section reduces with the increase in wall heat flux value. Copyright � Taylor & Francis Group, LLC.

We report on a two-dimensional highly ordered self-assembled monolayer (SAM) directly grown on a bare polymer surface. Semiconducting SAMs are utilized in field-effect transistors and combined into integrated circuits as 4-bit code generators. The driving force to form highly ordered SAMs is packing of the liquid crystalline molecules caused by the interactions between the linear alkane moieties and the π-π stacking of the conjugated thiophene units. The fully functional circuits demonstrate long-range order over large areas, which can be regarded as the start of flexible monolayer electronics. © 2010 American Chemical Society.

This paper discusses the results of an experimental and numerical study of fluid flow and heat transfer in an enclosure where multiple heaters are arranged in a staggered fashion. Experiments were carried out for Reynolds numbers, in the range 1800�?�Re�?�4500 and Grashof numbers in the range 2.5�נ104�?�Gr�?�3�נ105. Numerical simulations were carried out for two dimensional, steady, incompressible turbulent flow and the results of the numerical study are compared with the experimental results. The temperature distribution gives an insight into the power management among the heaters, so that the "coolest" heater can be loaded most to maximize the total heat dissipation, for a prescribed temperature excess, for all the heaters. Two methods are used to achieve the target temperature for all heaters, namely (i) trial and error method and (ii) the response surface method. The latter method was adopted, to simultaneously maximize the heat input and minimize the�temperature deviation from the target temperature, by employing a composite objective function. The numerically obtained optimal solution was finally verified by carrying out experiments. The method of response surface was found to be effective in optimizing the total heat transfer for a given target temperature. � 2009 Elsevier Masson SAS. All rights reserved.

This paper proposes directional Hartley transform (DirHT) in the Hartley domain by partitioning the two dimensional Hartley plane. Two different approaches, wrapping based directional Hartley transform (WDirHT) and overlapping based directional Hartley transform (ODirHT) have been proposed. WDirHT uses the Fourier integral operator (FIO) tiling scheme and ODirHT uses the ridgelet tiling scheme. WDirHT takes less computation time as compared to ODirHT, however, ODirHT has less redundancy factor as compared to WDirHT. The computational complexity of both WDirHT and ODirHT is O (N2 log2 N) for N � N image. The two dimensional Hartley plane is neither symmetric nor antisymmetric, hence, each Hartley directional subband coefficient in the two dimensional Hartley plane is unique. As a result, features obtained from the Hartley domain are unique. These features are exploited for content based image retrieval (CBIR) application. The proposed CBIR algorithm using WDirHT and ODirHT is applied on AT&T face and Brodatz textures databases. Results show that retrieval rate of both WDirHT and ODirHT is better as compared to several other methods. Among WDirHT and ODirHT, WDirHT gives better retrieval rate. � 2009 Elsevier B.V. All rights reserved.

We model the two-dimensional self-assembly of planar molecules capable of complementary interactions (like hydrogen bonding) as a set of hexagonal tiles on a hexagonal lattice. We use Monte Carlo simulations to study the phase diagrams of three model systems. The phases are characterized using a variety of order parameters, and they are studied as a function of the strength of the complementary interaction energy. This simplified model is proven to be capable of reproducing the phases encountered in real systems, unifying within the same framework most of the structures encountered experimentally.

Two new silver(I) complexes [Ag(barb)(pym)]center dot H2O (1) and [Ag(barb)(dmpy)]center dot 1.5H(2)O (2) (barb = 5,5-diethylbarbiturate, pym = pyridine-2-ylmethanol and dmpy = 2,6-dimethoxypyridine) have been synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. In both complexes, the silver(I) ions are linearly coordinated by the N atoms of a barb anion and a pym or a dmpy ligand, forming mononuclear species. The molecules of 1 and 2 are doubly bridged by N-H center dot center dot center dot O hydrogen bonds involving the barb moieties and these hydrogen-bonded dimers are assembled into two-dimensional layered networks through weak Ag center dot center dot center dot C-py (eta(1)) interactions of ca. 3.3 angstrom. Additionally, the thermal and fluorescent properties of these complexes are also investigated.

This Part 2 paper presents results of comparative experimental study of progressive damage in 2D and 3D woven glass/epoxy composites under in-plane tensile loading. As Part 1, this Part 2 work is focused on the comparison of in-plane tensile properties of two non-crimp single-ply 3D orthogonal weave E-glass fibre composites on one side and a laminate reinforced with four plies of E-glass plain weave on the other. The damage investigation methodology combines mechanical testing with acoustic emission registration (that provides damage initiation thresholds), progressive cracks observation on transparent samples, full-field surface strain mapping and cracks observation on micrographs, altogether enabling for a thorough characterisation of the local micro- and meso-damage modes of the studied composites. The obtained results demonstrate that the non-crimp 3D orthogonal woven composites have significantly higher in-plane strengths, failure strains and damage initiation thresholds than their 2D woven laminated counterpart. The growth of transverse cracks in the yarns of 3D composites is delayed, and they are less prone to a yarn-matrix interfacial crack formation and propagation. Delaminations developing between the plies of plain weave fabric in the laminate at certain load level never appear in the 3D woven single-ply composites. (C) 2009 Elsevier Ltd. All rights reserved. East-European PhD grant of K.U. Leuven Research Council (D.S. Ivanov) Department MTM

A new dinuclear silver(I)-saccharinato (sac) complex with acetonitrile (MeCN), [Ag-2(sac)(2)(MeCN)(2)](n) has been synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The silver(I) ions are doubly bridged by two sac ligands, leading to a short argentophilic contact of 2.9074(3) angstrom. Each silver(I) ion exhibits a square-planar coordination geometry including the Ag-Ag bonds. The individual dimeric molecules are extended into a two-dimensional layered structure by weak Ag center dot center dot center dot Csac(eta(2)) interactions of ca. 3.2 angstrom. These interactions were discussed and compared with those found in the first silver(I)-sac complex [Ag(sac)](n).

We present the follow-up of our previously published work, where we described a wavelet-based method to characterize the sea surface backscatter structures in Synthetic Aperture Radar (SAR) images. The method relies on the ability of the 2-D continuous wavelet technique to detect the spatial structure of the Marine Atmospheric Boundary Layer (MABL) and to isolate wind-related cells and features. The analysis of the cells' geometry, molded by the radiometric characteristics of the sea surface, permits the identification of the wind direction inside the cells, due to the along-wind asymmetry of backscatter structures, and thus the computation of the wind speed through standard algorithms. Twenty-one SAR images (ERS-2 and Envisat ASAR Wide Swath) over the Mediterranean Sea have been analyzed, and the results are compared with satellite wind fields. The images cover a range of meteorological conditions from low to moderate winds. Comparison of the SAR-derived wind fields with those provided by satellite scatterometers indicates a good score of success (roughly 70\%-80\%). The developed methodology, once tested over an adequate number of images to derive statistically reliable results, could be routinely used to enrich SAR images with the wind field as well as to characterize the MABL in terms of size, distribution, and shape of the backscatter cells.

Natural convection in a two-dimensional square cavity containing hydrodynamically and thermally anisotropic porous medium with internal heat generation is analyzed numerically by generalized non-Darcy approach. The properties considered for the study are permeability ratio (K *), inclination of the principal axes (?), ratio of Forchheimer constants (F *) and thermal conductivity ratio (k *). Results are presented in terms of isotherms, streamlines and maximum temperature in the cavity to understand the flow physics. It is observed that the anisotropic properties have significant influence on the flow behaviour and heat transfer. A correlation for maximum temperature in the cavity for a wide range of parameters (10 7 ? Ra ? 10 8, 10 -6 ? Da ? 10 -3, 0� ? ? ? 90�, 1 ? F * ? 100, 0.1 ? K * ? 10 and 0.1 ? k * ? 10) is developed. � 2008 Elsevier Ltd. All rights reserved.

In this paper, nonlinear aeroelastic behavior of a two-dimensional symmetric rotor blade in the dynamic stall regime is investigated. Two different oscillation models have been considered here: pitching oscillation and flap-edgewise oscillation. Stall aeroelastic instability in such systems can potentially lead to structural damage. Hence it is an important design concern, especially for wind turbines and helicopter rotors, where such modes of oscillation are likely to take place. Most previous analyses of such dynamical systems are not exhaustive. System parameters like structural nonlinearity or initial conditions have not been studied which could play a significant role on the overall dynamics. In the present paper, a parametric study on the aeroelastic instability and the nonlinear dynamical behavior of the system has been performed. Emphasis is given on the effect of structural nonlinearity and initial conditions. The aerodynamic loads in the dynamic stall regime have been computed using the Onera model. The qualitative influence of the system parameters is different in the two systems studied. The effect of structural nonlinearity on the bifurcation pattern of the system response is significant in the case of pitching oscillation. The initial condition plays an important role on the aeroelastic stability as well as on the bifurcation pattern in both the systems. In the forced response study, interesting dynamical behavior, like period-3 response, has been observed in the pitching oscillation case. On the other hand, for the flap-edgewise oscillation case, super-harmonic and quasi-harmonic response have been found. � 2008 Elsevier Ltd. All rights reserved.

In this study, a simulation/optimization (S/O) model is proposed for the identification of unknown groundwater well locations and pumping rates for two-dimensional aquifer systems. The proposed S/O model uses a finite-difference solution of governing groundwater flow equation as simulation model. This model is then combined with a genetic algorithm (GA) based optimization model which is used to determine the pumping rates for each well. To determine the well locations, an iterative moving sub-domain approach is proposed. The main advantage of this approach is that the optimization model only determines the pumping rates and it does not require the well locations as decision variables. The well locations are implicitly determined based on the results of pumping rate optimizations for different pre-defined well locations within sub-domains. The performance of the proposed S/O model is tested on two hypothetical aquifer models for both steady-state and transient flow conditions. In both cases, the identification procedure starts with one pumping well and systematically increases the number of the pumping wells until the best well configuration is identified. Determination of the best number of pumping wells is performed based on the residual errors (RE) between simulated and observed piezometric head values for given observation sites. Results indicated that when the number of pumping wells is greater than the true number of wells, the identified well configuration approaches to the true well configuration. Moreover, under steady-state flow conditions, the robustness of the proposed moving sub-domain approach is tested for different initial locations of sub-domains. Results showed that the true well locations are identified wherever the search process starts. Finally, the performance of the proposed S/O model is compared with a pure GA solution in which the well locations and pumping rates are treated as decision variables. Results indicate that the proposed S/O model finds smaller RE than the pure GA solution by performing 14% less simulations. © 2008 Elsevier B.V. All rights reserved.

In this paper we develop a mathematical model of the dynamics for an inflatable space reflector, which can be used to design a controller for the shape of the inflatable structure. Inflatable structures have very nice properties, suitable for aerospace applications. We can construct e.g. a huge light weight reflector for a satellite which consumes very little space in the rocket because it can be inflated when the satellite is in the orbit. So with this technology we can build inflatable reflectors which are about 100 times bigger than solid ones. But to be useful for telescopes we have to actively control the surface of the inflatable to achieve the desired surface accuracy. The starting point of the control design is modeling for control, in the case port-Hamiltonian (pH) modeling. We will show how to derive a nonlinear infinite dimensional pH model of a 1-D Euler-Bernoulli beam with piezo actuation. In the future we will also focus on 2-D models.

We consider the two-dimensional diffusion-advection equation ut = Duyy - frac(d k, d u) ux. We present the classification of Lie symmetries of this equation. For the case k(u) = u2 we give the complete list of similarity solutions. Exact and numerical solutions are obtained. © 2006 Elsevier Inc. All rights reserved. 187 2 1333 1350 Cited By :6

Atomically thin quaternary alloy of boron, nitrogen, carbon and oxygen, 2D-BNCO with tunable composition., In recent times, atomically thin alloys of boron, nitrogen, and carbon have generated significant excitement as a composition-tunable two-dimensional (2D) material that demonstrates rich physics as well as application potentials. The possibility of tunably incorporating oxygen, a group VI element, into the honeycomb sp2-type 2D-BNC lattice is an intriguing idea from both fundamental and applied perspectives. We present the first report on an atomically thin quaternary alloy of boron, nitrogen, carbon, and oxygen (2D-BNCO). Our experiments suggest, and density functional theory (DFT) calculations corroborate, stable configurations of a honeycomb 2D-BNCO lattice. We observe micrometer-scale 2D-BNCO domains within a graphene-rich 2D-BNC matrix, and are able to control the area coverage and relative composition of these domains by varying the oxygen content in the growth setup. Macroscopic samples comprising 2D-BNCO domains in a graphene-rich 2D-BNC matrix show graphene-like gate-modulated electronic transport with mobility exceeding 500 cm2 V−1 s−1, and Arrhenius-like activated temperature dependence. Spin-polarized DFT calculations for nanoscale 2D-BNCO patches predict magnetic ground states originating from the B atoms closest to the O atoms and sizable (0.6 eV < Eg < 0.8 eV) band gaps in their density of states. These results suggest that 2D-BNCO with novel electronic and magnetic properties have great potential for nanoelectronics and spintronic applications in an atomically thin platform.

Recently, with the impact of AJAX a new way of web development techniques have been emerged. Hence, with the help of this model, single-page web application was introduced which can be updated/replaced independently. Today we have a new challenge of building a powerful single-page application using the currently emerged technologies. Gaining an understanding of navigational model and user interface structure of the source application is the first step to successfully build a single- page application. In this paper, it explores not only building powerful single-page application but also Two Dimensional (2D) drawings on images and videos. Moreover, in this research it clearly express the findings on 2D multi-points polygon drawing concepts on client side; real-time data binding in between drawing module on image, video and view pages., 9 pages

Two haptic displays for virtual reality have recently been developed: one is an earth-grounded type, and the other a body-grounded type. There is now a great deal of research in this field, including work on a body-grounded type of device, a GyroCube, a moment-type display using a mechanical brake and a force display using a gyro moment. We have developed another kind of moment-type force display using a half-toroidal CVT (continuously variable transmission). In this paper, we report improvement the display weight and investigation of two dimensional display. And the human perception ability of direction has been confirmed by experiment.

Scattering from and propagation over rough-terrain profiles, as well as reentrant surfaces are investigated using an integral equation (IE)-based spectrally accelerated biconjugate gradient stabilized (SA-BiCGSTAB) method, with a storage requirement and a computational cost of O(N) per iteration, where N is the surface unknowns in the discretized IE. Numerical results in the form of current and path loss are presented and compared with previously published as well as measured results in order to assess the accuracy and efficiency of this method. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 158–162, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20930

FabIO is a Python module written for easy and transparent reading of raw two-dimensional data from various X-ray detectors. The module provides a function for reading any image and returning a fabioimage object which contains both metadata (header information) and the raw data. All fabioimage objects offer additional methods to extract information about the image and to open other detector images from the same data series.