WorldWideScience

Sample records for 3d triangular lattice

  1. RNA folding on the 3D triangular lattice

    Directory of Open Access Journals (Sweden)

    Mayne Martin

    2009-11-01

    Full Text Available Abstract Background Difficult problems in structural bioinformatics are often studied in simple exact models to gain insights and to derive general principles. Protein folding, for example, has long been studied in the lattice model. Recently, researchers have also begun to apply the lattice model to the study of RNA folding. Results We present a novel method for predicting RNA secondary structures with pseudoknots: first simulate the folding dynamics of the RNA sequence on the 3D triangular lattice, next extract and select a set of disjoint base pairs from the best lattice conformation found by the folding simulation. Experiments on sequences from PseudoBase show that our prediction method outperforms the HotKnot algorithm of Ren, Rastegari, Condon and Hoos, a leading method for RNA pseudoknot prediction. Our method for RNA secondary structure prediction can be adapted into an efficient reconstruction method that, given an RNA sequence and an associated secondary structure, finds a conformation of the sequence on the 3D triangular lattice that realizes the base pairs in the secondary structure. We implemented a suite of computer programs for the simulation and visualization of RNA folding on the 3D triangular lattice. These programs come with detailed documentation and are accessible from the companion website of this paper at http://www.cs.usu.edu/~mjiang/rna/DeltaIS/. Conclusion Folding simulation on the 3D triangular lattice is effective method for RNA secondary structure prediction and lattice conformation reconstruction. The visualization software for the lattice conformations of RNA structures is a valuable tool for the study of RNA folding and is a great pedagogic device.

  2. Pattern design on 3D triangular garment surfaces

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper focuses on a pattern design method for a 3D triangular garment surface. Firstly, some definitions of 3D style lines are proposed for designing the boundaries of patterns as drawing straight lines or splines on the triangular surface.Additionally some commonly used style lines are automatically generated to enhance design efficiency. Secondly, after style lines are preprocessed, a searching method is presented for quickly obtaining the boundaries and patches of a pattern on the 3D triangular surface. Finally a new pattern design reuse method is introduced by encoding/decoding the style line information. After style lines are encoded, the pattern design information can be saved in a pattern template and when decoding this template on a new garment surface, it automates the pattern generation for made-to-measure apparel products.

  3. Ultracold quantum gases in triangular optical lattices

    International Nuclear Information System (INIS)

    Over recent years, exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand experimental environments with non-cubic lattice geometries. In this paper, we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step, the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this, we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that, below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-dependent interaction. Interestingly, this opens up new perspectives for a lattice-driven tuning of a spin dynamics resonance occurring through the interplay of the quadratic Zeeman effect and spin-dependent interaction. Finally, we discuss further lattice configurations that can be realized with our setup.

  4. Ultracold quantum gases in triangular optical lattices

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C; Soltan-Panahi, P; Doerscher, S; Sengstock, K [Institut fuer Laserphysik, Universitaet Hamburg, Hamburg D-22761 (Germany); Kronjaeger, J; Bongs, K, E-mail: cbecker@physnet.uni-hamburg.d [MUARC, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2010-06-15

    Over recent years, exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand experimental environments with non-cubic lattice geometries. In this paper, we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step, the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this, we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that, below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-dependent interaction. Interestingly, this opens up new perspectives for a lattice-driven tuning of a spin dynamics resonance occurring through the interplay of the quadratic Zeeman effect and spin-dependent interaction. Finally, we discuss further lattice configurations that can be realized with our setup.

  5. Effective Medium Theory of Filamentous Triangular Lattice

    OpenAIRE

    Mao, Xiaoming; Stenull, Olaf; Lubensky, T. C.

    2011-01-01

    We present an effective medium theory that includes bending as well as stretching forces, and we use it to calculate mechanical response of a diluted filamentous triangular lattice. In this lattice, bonds are central-force springs, and there are bending forces between neighboring bonds on the same filament. We investigate the diluted lattice in which each bond is present with a probability $p$. We find a rigidity threshold $p_b$ which has the same value for all positive bending rigidity and a...

  6. Ultracold quantum gases in triangular optical lattices

    CERN Document Server

    Becker, C; Kronjäger, J; Dörscher, S; Bongs, K; Sengstock, K

    2009-01-01

    Over the last years the exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand for experimental environments with non-cubic lattice geometries. In this paper we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-d...

  7. Visualization of 3D optical lattices

    Science.gov (United States)

    Lee, Hoseong; Clemens, James

    2016-05-01

    We describe the visualization of 3D optical lattices based on Sisyphus cooling implemented with open source software. We plot the adiabatic light shift potentials found by diagonalizing the effective Hamiltonian for the light shift operator. Our program incorporates a variety of atomic ground state configurations with total angular momentum ranging from j = 1 / 2 to j = 4 and a variety of laser beam configurations including the two-beam lin ⊥ lin configuration, the four-beam umbrella configuration, and four beams propagating in two orthogonal planes. In addition to visualizing the lattice the program also evaluates lattice parameters such as the oscillation frequency for atoms trapped deep in the wells. The program is intended to help guide experimental implementations of optical lattices.

  8. Mechanical Properties of 3-D Printed Cellular Foams with triangular cells

    Science.gov (United States)

    Bunga, Pratap Kumar

    In the present work, poly lactic acid (PLA) is used as a model system to investigate the mechanical behavior of 3-D printed foams with triangular cells. Solid PLA tension and compression specimens and foams made of PLA were fabricated using fused deposition 3-D printing technique. The solid PLA tension specimens were characterized for their densities and found to be about 10% lower in density as compared to their bulk counter parts. The triangular foams had a relative density of about 64%. The relationships between the structure of the foams and its deformation behavior under compression along two in-plane directions were characterized. Furthermore, simple finite element models were developed to understand the observed deformation behavior of triangular foams.

  9. An integrable 3D lattice model with positive Boltzmann weights

    CERN Document Server

    Mangazeev, Vladimir V; Sergeev, Sergey M

    2013-01-01

    In this paper we construct a three-dimensional (3D) solvable lattice model with non-negative Boltzmann weights. The spin variables in the model are assigned to edges of the 3D cubic lattice and run over an infinite number of discrete states. The Boltzmann weights satisfy the tetrahedron equation, which is a 3D generalisation of the Yang-Baxter equation. The weights depend on a free parameter 03D lattice model with non-negative Boltzmann weights.

  10. Mott Insulating Ground State on a Triangular Surface Lattice

    International Nuclear Information System (INIS)

    Momentum-resolved direct and inverse photoemission spectra of the K/Si(111)-(√(3)x√(3))R30 degree-B interface reveals the presence of strongly localized surface states. The K overlayer remains nonmetallic up to the saturation coverage. This system most likely presents the first experimental realization of a frustrated spin 1/2 Heisenberg antiferromagnet on a two-dimensional triangular lattice. copyright 1997 The American Physical Society

  11. Many body localization in two dimensional square and triangular lattices

    CERN Document Server

    Gonzalez-Garcia, L; Paredes, R

    2016-01-01

    Ultracold interacting Bose atoms placed in disordered two dimensional optical lattices with square and triangular symmetries are found to be localized above a certain disorder strength amplitude. From a Gross-Pitaevskii mean analysis we determine the localization length as a function of the disorder strength and investigate the energy spectrum in terms of the disorder magnitude. We found that the localization length is observed to decrease faster in triangular geometries than in square ones. In the presence of a harmonic confinement localization is observed at the center of the trap. The analysis of the energy spectrum reveals that discrete energy levels acquire a finite width that is always smaller than the distance among energy levels.

  12. Mott transition and magnetism on the anisotropic triangular lattice

    OpenAIRE

    Acheche, S.; Reymbaut, A.; Charlebois, M.; Sénéchal, D.; Tremblay, A.-M.S.

    2016-01-01

    Spin-liquid behavior was recently suggested experimentally in the moderately one-dimensional organic compound $\\kappa$-H$_3$(Cat-EDT-TTF)$_2$. This compound can be modeled by the one-band Hubbard model on the anisotropic triangular lattice with $t^\\prime/t \\simeq 1.5$, where $t'$ is the minority hopping. It thus becomes important to extend previous studies, that were performed in the range $0 \\leq t'/t \\leq 1.2$, to find out whether there is a regime where Mott insulating behavior can be foun...

  13. TRIHEX-3D: A multigroup diffusion theory code for hexagonal lattice core analyses with auto-triangularisation

    International Nuclear Information System (INIS)

    A multigroup diffusion theory code, TRIHEX-3D, has been developed for hexagonal lattice core analyses. For 2-D problems one can use hexagonal or triangular centre-mesh finite difference (FD) schemes. The geometrical description of the problem is for hexagonal geometry only. Subdivision of each hexagon into uniform triangles is facilitated by a built-in auto-triangularisati on procedure. One can analyse any symmetric part of the core or the whole core as well. Reflective (30deg, 60deg, 90deg, 120deg and 180deg) and rotational (60deg, 120deg and 180deg) symmetry boundary conditions are allowed. For 3-D problems one can use a direct 3-D FDM or an axial flux synthesis method. TRIHEX-3D can be used for the core design problems of VVER type of hexagonal lattice cores. The code has been validated against a LMFBR SNR-300 benchmark problem. (author). 8 tabs., 9 figs., 9 refs., 5 appendixes

  14. Lattice percolation approach to 3D modeling of tissue aging

    Science.gov (United States)

    Gorshkov, Vyacheslav; Privman, Vladimir; Libert, Sergiy

    2016-11-01

    We describe a 3D percolation-type approach to modeling of the processes of aging and certain other properties of tissues analyzed as systems consisting of interacting cells. Lattice sites are designated as regular (healthy) cells, senescent cells, or vacancies left by dead (apoptotic) cells. The system is then studied dynamically with the ongoing processes including regular cell dividing to fill vacant sites, healthy cells becoming senescent or dying, and senescent cells dying. Statistical-mechanics description can provide patterns of time dependence and snapshots of morphological system properties. The developed theoretical modeling approach is found not only to corroborate recent experimental findings that inhibition of senescence can lead to extended lifespan, but also to confirm that, unlike 2D, in 3D senescent cells can contribute to tissue's connectivity/mechanical stability. The latter effect occurs by senescent cells forming the second infinite cluster in the regime when the regular (healthy) cell's infinite cluster still exists.

  15. Photonic-crystal slabs with a triangular lattice of triangular holes investigated using a guided-mode expansion method

    CERN Document Server

    Andreani, L C

    2006-01-01

    According to a recent proposal [S. Takayama et al., Appl. Phys. Lett. 87, 061107 (2005)], the triangular lattice of triangular air holes may allow to achieve a complete photonic band gap in two-dimensional photonic crystal slabs. In this work we present a systematic theoretical study of this photonic lattice in a high-index membrane, and a comparison with the conventional triangular lattice of circular holes, by means of the guided-mode expansion method whose detailed formulation is described here. Photonic mode dispersion below and above the light line, gap maps, and intrinsic diffraction losses of quasi-guided modes are calculated for the periodic lattice as well as for line- and point-defects defined therein. The main results are summarized as follows: (i) the triangular lattice of triangular holes does indeed have a complete photonic band gap for the fundamental guided mode, but the useful region is generally limited by the presence of second-order waveguide modes; (ii) the lattice may support the usual p...

  16. The 3D solitons and vortices in 3D discrete monatomic lattices with cubic and quartic nonlinearity

    Institute of Scientific and Technical Information of China (English)

    Xu Quan; Tian Qiang

    2006-01-01

    By virtue of the method of multiple-scale and the quasi-discreteness approach, we have discussed the nonlinear vibration equation of a 3D discrete monatomic lattice with its nearest-neighbours interaction. The 3D simple cubic lattices have the same localized modes as a ID discrete monatomic chain with cubic and quartic nonlinearity. The nonlinear vibration in the 3D simple cubic lattice has 3D distorted solitons and 3D envelop solitons in the direction of kx = ky = kz = k and k =±π/6a0 in the Brillouin zone, as well as has 3D vortices in the direction of kx = ky = kz = k and k =±π/a0 in the Brillouin zone.

  17. Clar Sextet Analysis of Triangular, Rectangular, and Honeycomb Graphene Antidot Lattices

    DEFF Research Database (Denmark)

    Petersen, Rene; Pedersen, Thomas Garm; Jauho, Antti-Pekka

    2011-01-01

    triangular, and the honeycomb lattice. It is found that the lattice geometry plays a crucial role for size of the band gap the triangular arrangement displays always a shable gap, while for the other types only particular hole separations lead to a large gap. This observation is explained using, Clear sextet...

  18. Design of Mott and topological phases on buckled 3d-oxide honeycomb lattices

    Science.gov (United States)

    Pentcheva, Rossitza

    The honeycomb lattice, as realized e.g. in graphene, has rendered a robust platform for innovative science and potential applications. A much richer generalization of this lattice arises in (111)-oriented bilayers of perovskites, adding the complexity of the strongly correlated, multiorbital nature of electrons in transition metal oxides. Based on first principles calculations with an on-site Coulomb repulsion, here we provide trends in the evolution of ground states versus band filling in (111)-oriented (La XO3)2 /(LaAlO3)4 superlattices, with X spanning the entire 3d transition metal series. The competition between local quasi-cubic and global triangular symmetry triggers unanticipated broken symmetry phases, with mechanisms ranging from Jahn-Teller distortion, to charge-, spin-, and orbital-ordering. LaMnO3 and LaCoO3 bilayers, where spin-orbit coupling opens a sizable gap in the Dirac-point Fermi surface, emerge as much desired oxide-based Chern insulators, the latter displaying a gap capable of supporting room-temperature applications Further realizations of the honeycomb lattice and geometry patterns beyond the perovskite structure will be addressed. Research supported by the DFG, SFB/TR80.

  19. SFM-FDTD analysis of triangular-lattice AAA structure: Parametric study of the TEM mode

    Science.gov (United States)

    Hamidi, M.; Chemrouk, C.; Belkhir, A.; Kebci, Z.; Ndao, A.; Lamrous, O.; Baida, F. I.

    2014-05-01

    This theoretical work reports a parametric study of enhanced transmission through annular aperture array (AAA) structure arranged in a triangular lattice. The effect of the incidence angle in addition to the inner and outer radii values on the evolution of the transmission spectra is carried out. To this end, a 3D Finite-Difference Time-Domain code based on the Split Field Method (SFM) is used to calculate the spectral response of the structure for any angle of incidence. In order to work through an orthogonal unit cell which presents the advantage to reduce time and space of computation, special periodic boundary conditions are implemented. This study provides a new modeling of AAA structures useful for producing tunable ultra-compact devices.

  20. Quantum electric-dipole liquid on a triangular lattice

    Science.gov (United States)

    Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F.; Sun, Young

    2016-01-01

    Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics. PMID:26843363

  1. Control of lattice spacing in a triangular lattice of feeble magnetic particles formed by induced magnetic dipole interactions

    OpenAIRE

    Noriyuki Hirota, Tsutomu Ando, Ryo Tanaka, Hitoshi Wada and Yoshio Sakka

    2009-01-01

    We studied methods of controlling the spacing between particles in the triangular lattice formed by feeble magnetic particles through induced magnetic dipole interaction. Formation of a triangular lattice is described by the balance between the magnetic force and the interaction of induced magnetic dipoles. The intensity of the magnetic force is proportional to the volume of particles V and the difference in the magnetic susceptibilities between the particles and the surrounding medium Δχ. On...

  2. Tilted resonators in a triangular elastic lattice: chirality, Bloch waves and negative refraction

    CERN Document Server

    Tallarico, Domenico; Movchan, Alexander B; Colquitt, Daniel J

    2016-01-01

    We consider a vibrating triangular mass-truss lattice whose unit cell contains a resonator of a triangular shape. The resonators are connected to the triangular lattice by trusses. Each resonator is tilted, i.e. it is rotated with respect to the triangular lattice's unit cell through an angle $\\vartheta_0$. This geometrical parameter is responsible for the emergence of a resonant mode in the Bloch spectrum for elastic waves and strongly affects the dispersive properties of the lattice. Additionally, the tilting angle $\\vartheta_0$ triggers the opening of a band gap at a Dirac-like point. We provide a physical interpretation of these phenomena and discuss the dynamical implications on elastic Bloch waves. The dispersion properties are used to design a structured interface containing tilted resonators which exhibit negative refraction and focussing, as in a "flat elastic lens".

  3. The scaling limit of the correlation of holes on the triangular lattice with periodic boundary conditions

    OpenAIRE

    Ciucu, Mihai

    2005-01-01

    We define the correlation of holes on the triangular lattice under periodic boundary conditions and study its asymptotics as the distances between the holes grow to infinity. We prove that the joint correlation of an arbitrary collection of lattice-triangular holes of even sides satisfies, for large separations between the holes, a Coulomb law and a superposition principle that perfectly parallel the laws of two dimensional electrostatics, with physical charges corresponding to holes, and the...

  4. Extended particle swarm optimisation method for folding protein on triangular lattice.

    Science.gov (United States)

    Guo, Yuzhen; Wu, Zikai; Wang, Ying; Wang, Yong

    2016-02-01

    In this study, the authors studied the protein structure prediction problem by the two-dimensional hydrophobic-polar model on triangular lattice. Particularly the non-compact conformation was modelled to fold the amino acid sequence into a relatively larger triangular lattice, which is more biologically realistic and significant than the compact conformation. Then protein structure prediction problem was abstracted to match amino acids to lattice points. Mathematically, the problem was formulated as an integer programming and they transformed the biological problem into an optimisation problem. To solve this problem, classical particle swarm optimisation algorithm was extended by the single point adjustment strategy. Compared with square lattice, conformations on triangular lattice are more flexible in several benchmark examples. They further compared the authors' algorithm with hybrid of hill climbing and genetic algorithm. The results showed that their method was more effective in finding solution with lower energy and less running time.

  5. Extended particle swarm optimisation method for folding protein on triangular lattice.

    Science.gov (United States)

    Guo, Yuzhen; Wu, Zikai; Wang, Ying; Wang, Yong

    2016-02-01

    In this study, the authors studied the protein structure prediction problem by the two-dimensional hydrophobic-polar model on triangular lattice. Particularly the non-compact conformation was modelled to fold the amino acid sequence into a relatively larger triangular lattice, which is more biologically realistic and significant than the compact conformation. Then protein structure prediction problem was abstracted to match amino acids to lattice points. Mathematically, the problem was formulated as an integer programming and they transformed the biological problem into an optimisation problem. To solve this problem, classical particle swarm optimisation algorithm was extended by the single point adjustment strategy. Compared with square lattice, conformations on triangular lattice are more flexible in several benchmark examples. They further compared the authors' algorithm with hybrid of hill climbing and genetic algorithm. The results showed that their method was more effective in finding solution with lower energy and less running time. PMID:26816397

  6. Long-lived dipolar molecules and Feshbach molecules in a 3D optical lattice

    CERN Document Server

    Chotia, Amodsen; Moses, Steven A; Yan, Bo; Covey, Jacob P; Foss-Feig, Michael; Rey, Ana Maria; Jin, Deborah S; Ye, Jun

    2011-01-01

    We have realized long-lived ground-state polar molecules in a 3D optical lattice, with a lifetime of up to 25 s, which is limited only by off-resonant scattering of the trapping light. Starting from a 2D optical lattice, we observe that the lifetime increases dramatically as a small lattice potential is added along the tube-shaped lattice traps. The 3D optical lattice also dramatically increases the lifetime for weakly bound Feshbach molecules. For a pure gas of Feshbach molecules, we observe a lifetime of >20 s in a 3D optical lattice; this represents a 100-fold improvement over previous results. This lifetime is also limited by off-resonant scattering, the rate of which is related to the size of the Feshbach molecule. Individually trapped Feshbach molecules in the 3D lattice can be converted to pairs of K and Rb atoms and back with nearly 100% efficiency.

  7. PLASTIC ZONE OF SEMI-INFINITE CRACK INPLANAR KAGOME AND TRIANGULAR LATTICES

    Institute of Scientific and Technical Information of China (English)

    Xinming Qiu; Lianghong He; Yueqiang Qian; Xiong Zhang

    2009-01-01

    The fracture investigations of the planar lattices made of ductile cell walls are cur-rently limited to bending-dominated hexagonal honeycomb. In this paper, the plastic zones of stretching-dominated lattices, including Kagome and triangular lattices, are estimated by ana-lyzing their effective yield loci. The normalized in-plane yield loci of these two lattices are almost identical convex curves enclosed by 4 straight lines, which is almost independent of the relative density but is highly sensitive to the principal stress directions. Therefore, the plastic zones around the crack tip of Kagome and triangular are estimated to be quite different to those of the con-tinuum solid and also hexagonal lattice. The plastic zones predictions by convex yield surfaces of both lattices are validated by FE calculations, although the shear lag region caused by non-local bending effect in the Kagome lattice enlarges the plastic zone in cases of small ratio of Tp/l.

  8. Control of lattice spacing in a triangular lattice of feeble magnetic particles formed by induced magnetic dipole interactions

    Directory of Open Access Journals (Sweden)

    Noriyuki Hirota, Tsutomu Ando, Ryo Tanaka, Hitoshi Wada and Yoshio Sakka

    2009-01-01

    Full Text Available We studied methods of controlling the spacing between particles in the triangular lattice formed by feeble magnetic particles through induced magnetic dipole interaction. Formation of a triangular lattice is described by the balance between the magnetic force and the interaction of induced magnetic dipoles. The intensity of the magnetic force is proportional to the volume of particles V and the difference in the magnetic susceptibilities between the particles and the surrounding medium Δχ. On the other hand, the intensity of the induced magnetic dipole interaction depends on the square of V and Δχ. Therefore, altering the magnetic susceptibility difference by changing the susceptibility of the surrounding medium, volume of the particles, and intensity and spatial distribution of the applied magnetic field effectively controls the distance between the particles. In this study, these three methods were evaluated through experiment and molecular dynamics simulations. The distance between the particles, i.e. the lattice constant of the triangular lattice, was varied from 1.7 to 4.0 in units of the particle diameter. Formation of self-organized triangular lattice through the induced magnetic dipole interaction is based on magnetism, a physical property that all materials have. Therefore, this phenomenon is applicable to any materials of any size. Consequently, structure formation through induced magnetic dipole interaction is a potential way of fabricating materials with ordered structures.

  9. Heavy dense QCD from a 3d effective lattice theory

    CERN Document Server

    Glesaaen, Jonas; Philipsen, Owe

    2015-01-01

    The cold and dense regime of the QCD phase diagram is to this day inaccessible to first principle lattice calculations owing to the sign problem. Here we present progress of an ongoing effort to probe this particularly difficult regime utilising a dimensionally reduced effective lattice theory with a significantly reduced sign problem. The effective theory is derived by combined character and hopping expansion and is valid for heavy quarks near the continuum. We show an extension of the effective theory to order $u^5\\kappa^8$ in the cold regime. A linked cluster expansion is applied to the effective theory resulting in a consistent mechanism for handling the effective theory fully analytically. The new results are consistent with the ones from simulations confirming the viability of analytic methods. Finally we resum the analytical result which doubles the convergence region of the expansion.

  10. A Line Generation Algorithm over 3D Body-centered Cubic Lattice

    Directory of Open Access Journals (Sweden)

    Lijun He

    2013-02-01

    Full Text Available New line generation algorithm is proposed for generating lines over 3D body-centered cubic lattice, a kind of optimal lattice in 3D space. The main contribution in this paper is employing the 3D Bresenham algorithm, a popular algorithm for generating 3D lines on a cubic lattice, to produce the BCC lattice occupied by 3D lines, with the help of the adjunct parallelepiped space, having the same center and basis vectors with the BCC lattice. The adjunct parallelepiped line is easy to generate by employing the existed 3D cubic Bresenhan algorithm. Due to the one-to-one correspondence between the parallelogram cells of parallelepiped space and the voxels of the BCC space, the 3D BCC line generation algorithm is gained. The whole procedure is characterized by a simple discriminator and a derivation for this discriminator given in the paper confirms that all calculations can be realized using only integer arithmetic which is to implement on computer.

  11. A lattice-Boltzmann scheme of the Navier-Stokes equations on a 3D cuboid lattice

    Science.gov (United States)

    Min, Haoda; Peng, Cheng; Wang, Lian-Ping

    2015-11-01

    The standard lattice-Boltzmann method (LBM) for fluid flow simulation is based on a square (in 2D) or cubic (in 3D) lattice grids. Recently, two new lattice Boltzmann schemes have been developed on a 2D rectangular grid using the MRT (multiple-relaxation-time) collision model, by adding a free parameter in the definition of moments or by extending the equilibrium moments. Here we developed a lattice Boltzmann model on 3D cuboid lattice, namely, a lattice grid with different grid lengths in different spatial directions. We designed our MRT-LBM model by matching the moment equations from the Chapman-Enskog expansion with the Navier-Stokes equations. The model guarantees correct hydrodynamics. A second-order term is added to the equilibrium moments in order to restore the isotropy of viscosity on a cuboid lattice. The form and the coefficients of the extended equilibrium moments are determined through an inverse design process. An additional benefit of the model is that the viscosity can be adjusted independent of the stress-moment relaxation parameter, thus improving the numerical stability of the model. The resulting cuboid MRT-LBM model is then validated through benchmark simulations using laminar channel flow, turbulent channel flow, and the 3D Taylor-Green vortex flow.

  12. Fast Tree Search for A Triangular Lattice Model of Protein Folding

    Institute of Scientific and Technical Information of China (English)

    Xiaomei Li; Nengchao Wang

    2004-01-01

    Using a triangular lattice model to study the designability of protein folding, we overcame the parity problem of previous cubic lattice model and enumerated all the sequences and compact structures on a simple two-dimensional triangular lattice model of size 4+5+6+5+4. We used two types of amino acids, hydrophobic and polar, to make up the sequences, and achieved 223+212 different sequences excluding the reverse symmetry sequences. The total string number of distinct compact structures was 219,093, excluding reflection symmetry in the self-avoiding path of length 24 triangular lattice model. Based on this model, we applied a fast search algorithm by constructing a cluster tree. The algorithm decreased the computation by computing the objective energy of non-leaf nodes. The parallel experiments proved that the fast tree search algorithm yielded an exponential speed-up in the model of size 4+5+6+5+4. Designability analysis was performed to understand the search result.

  13. Controlling the focusing properties of a triangular-lattice metallic photonic-crystal slab

    Institute of Scientific and Technical Information of China (English)

    Feng Shuai; Wang Yi-Quan; Li Zhi-Yuan; Cheng Bing-Ying; Zhang Dao-Zhong

    2007-01-01

    This paper studies the focusing properties of a two-dimensional photonic crystal (PC) slab consisting of a triangular lattice of metallic cylinders immersed in a dielectric background. Through the analysis of the equifrequency-surface contours and the field patterns of a point source placed in the vicinity of the PC slab, it finds that both the image distance and image quality can be controlled by simply adjusting the refractive index of the background material.

  14. Anisotropic Hubbard model on a triangular lattice - spin dynamics in HoMnO3

    Indian Academy of Sciences (India)

    Saptarshi Ghosh; Avinash Singh

    2008-01-01

    The recent neutron scattering data for spin-wave dispersion in HoMnO3 are well-described by an anisotropic Hubbard model on a triangular lattice with a planar (XY) spin anisotropy. Best fit indicates that magnetic excitations in HoMnO3 correspond to the strong-coupling limit / > ∼ 15, with planar exchange energy = 42/ ≃ 2.5 meV and planar anisotropy ≃ 0.35 meV.

  15. Magnetization Process of Spin-1/2 Heisenberg Antiferromagnets on a Layered Triangular Lattice

    Science.gov (United States)

    Yamamoto, Daisuke; Marmorini, Giacomo; Danshita, Ippei

    2016-02-01

    We study the magnetization process of the spin-1/2 antiferromagnetic Heisenberg model on a layered triangular lattice by means of a numerical cluster mean-field method with a scaling scheme (CMF+S). It has been known that antiferromagnetic spins on a two-dimensional (2D) triangular lattice with quantum fluctuations exhibit a one-third magnetization plateau in the magnetization curve under magnetic field. We demonstrate that the CMF+S quantitatively reproduces the magnetization curve including the stabilization of the plateau. We also discuss the effects of a finite interlayer coupling, which is unavoidable in real quasi-2D materials. It has been recently argued for a model of the layered-triangular-lattice compound Ba3CoSb2O9 that such interlayer coupling can induce an additional first-order transition at a strong field. We present the detailed CMF+S results for the magnetization and susceptibility curves of the fundamental Heisenberg Hamiltonian in the presence of magnetic field and weak antiferromagnetic interlayer coupling. The extra first-order transition appears as a quite small jump in the magnetization curve and a divergence in the susceptibility at a strong magnetic field ˜0.712 of the saturation field.

  16. Hofstadter problem on the honeycomb and triangular lattices: Bethe ansatz solution

    Science.gov (United States)

    Kohmoto, M.; Sedrakyan, A.

    2006-06-01

    We consider Bloch electrons on the honeycomb lattice under a uniform magnetic field with 2πp/q flux per cell. It is shown that the problem factorizes to two triangular lattices. Treating magnetic translations as a Heisenberg-Weyl group and by the use of its irreducible representation on the space of theta functions, we find a nested set of Bethe equations, which determine the eigenstates and energy spectrum. The Bethe equations have simple form which allows us to consider them further in the limit p,q→∞ by the technique of thermodynamic Bethe ansatz and analyze the Hofstadter problem for the irrational flux.

  17. Hofstadter Problem on the Honeycomb and Triangular Lattices: Bethe Ansatz Solution

    OpenAIRE

    Kohmoto, M.; Sedrakyan, A.

    2006-01-01

    We consider Bloch electrons on the honeycomb lattice under a uniform magnetic field with $2 \\pi p/q$ flux per cell. It is shown that the problem factorizes to two triangular lattices. Treating magnetic translations as Heisenberg-Weyl group and by the use of its irreducible representation on the space of theta functions, we find a nested set of Bethe equations, which determine the eigenstates and energy spectrum. The Bethe equations have simple form which allows to consider them further in the...

  18. Spontaneous formation of kagome network and Dirac half-semimetal on a triangular lattice

    Science.gov (United States)

    Akagi, Yutaka; Motome, Yukitoshi

    2015-04-01

    In spin-charge coupled systems, geometrical frustration of underlying lattice structures can give rise to nontrivial magnetic orders and electronic states. Here we explore such a possibility in the Kondo lattice model with classical localized spins on a triangular lattice by using a variational calculation and simulated annealing. We find that the system exhibits a four-sublattice collinear ferrimagnetic phase at 5/8 filling for a large Hund's-rule coupling. In this state, the system spontaneously differentiates into the up-spin kagome network and the isolated down-spin sites, which we call the kagome network formation. In the kagome network state, the system becomes Dirac half-semimetallic: The electronic structure shows a massless Dirac node at the Fermi level, and the Dirac electrons are almost fully spin polarized due to the large Hund's-rule coupling. We also study the effect of off-site Coulomb repulsion in the kagome network phase where the system is effectively regarded as a 1/3-filling spinless fermion system on the kagome lattice. We find that, at the level of the mean-field approximation, a √{3 }×√{3 } -type charge order occurs in the kagome network state, implying the possibility of fractional charge excitations in this triangular lattice system. Moreover, we demonstrate that the kagome network formation with fully polarized Dirac electrons are controllable by an external magnetic field.

  19. Absolute band gaps of a two-dimensional triangular-lattice dielectric photonic crystal with different shapes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Absolute band gaps of a two-dimensional triangular-lattice photonic crystal are calculated with the finite-difference time-domain method in this paper.Through calculating the photonic band structures of the triangular-lattice photonic crystal consisting of Ge rods immersed in air with different shapes,it is found that a large absolute band gap of 0.098 (2c/a) can be obtained for the structures with hollow triangular Ge rods immersed in air,corresponding to 19.8% of the middle frequency.The influence of the different factors on the width of the absolute band gaps is also discussed.

  20. Spin superfluidity in the anisotropic XY model in the triangular lattice

    Science.gov (United States)

    Lima, L. S.

    2016-07-01

    We use the SU(3) Schwinger's boson theory to study the spin transport properties in the two-dimensional anisotropic frustrated Heisenberg model in the triangular lattice at T=0. We have investigated the behavior of the spin conductivity for this model which presents an single-ion anisotropy. We study the spin transport in the Bose-Einstein condensation regime where we have that the tz bosons are condensed and the following condition is valid: = = t . Our results show a metallic spin transport for ω > 0 and a superfluid spin transport in the limit of DC conductivity, ω → 0 , where σ(ω) tends to infinity in this limit of ω.

  1. The density of states for an antiferromagnetic Ising model on a triangular lattice

    Institute of Scientific and Technical Information of China (English)

    XIA Kai; YAO Xiao-yan; LIU Jun-ming

    2007-01-01

    The Wang-Landau algorithm is an efficient Monte Carlo approach to the density of states of a statistical mechanics system.The estimation of state density would allow the computation of thermodynamic properties of the system over the whole temperature range.We apply this sampling method to study the phase transitions in a triangular Ising model.The entropy of the lattice at zero temperature as well as other thermodynamic properties is computed.The calculated thermodynamic properties are explained in the context of the magnetic phase transition.

  2. An improvement of the lattice theory of dislocation for a two-dimensional triangular crystal

    Institute of Scientific and Technical Information of China (English)

    Wang Shao-Feng

    2005-01-01

    The structure of dislocation in a two-dimensional triangular crystal has been studied theoretically on the basis of atomic interaction and lattice statics. The theory presented in this paper is an improvement to that published previously.Within a reasonable interaction approximation, a new dislocation equation is obtained, which remedies a fault existing in the lattice theory of dislocation. A better simplification of non-diagonal terms of the kernel is given. The solution of the new dislocation equation asymptotically becomes the same as that obtained in the elastic theory, and agrees with experimental data. It is found that the solution is formally identical with that proposed phenomenologically by Foreman et al, where the parameter can be chosen freely, but cannot uniquely determined from theory. Indeed, if the parameter in the expression of the solution is selected suitably, the expression can be well applied to describe the fine structure of the dislocation.

  3. Multiphoton ionization of atoms on 2D and 3D spatial lattices

    International Nuclear Information System (INIS)

    The two photon ionization rate for the Lithium atom is calculated by direct solution of the time dependent Schrodinger's equation on a 2D cylindrical coordinate lattice. A variable mesh finite difference method is formulated. The ionization rates are found to be in good agreement with perturbation theory at low laser intensities, but are substantially smaller at the higher intensities. The three photon ionization rate for the Hydrogen atom is calculated by direct solution of the time dependent Schrodinger's equation on a 3D cartesian coordinate lattice. Uniform mesh finite difference and finite element methods are formulated. The 3D lattice permits ionization rate calculations for both linear and circular polarized light. The ionization rates for the two different polarizations are found to be nearly equal for intensities a few times 1014 Watts/cm2; in sharp contrast to the perturbation theory prediction of a factor of 10 difference. Numerical computations were performed on both a Cray Y-MP C90 and a 128 node Intel 860

  4. Near-elliptic core triangular-lattice and square-lattice PCFs: a comparison of birefringence, cut-off and GVD characteristics towards fiber device application

    CERN Document Server

    Maji, Partha Sona

    2014-01-01

    In this work, detailed numerical analysis of the near-elliptic core index-guiding triangular-lattice and square-lattice photonic crystal fiber (PCFs) are reported for birefringence, single mode, cut-off behavior, group velocity dispersion and effective area properties. For the same relative values of d/P, triangular-lattice PCFs show higher birefringence whereas the square-lattice PCFs show a wider range of single-mode operation. Square-lattice PCF was found to be endlessly single-mode for higher air-filling fraction (d/P). Smaller lengths of triangular-lattice PCF are required for dispersion compensation whereas PCFs with square-lattice with nearer relative dispersion slope (RDS) can better compensate the broadband dispersion. Square-lattice PCFs show ZDW red-shifted, making it preferable for mid-IR supercontinuum generation (SCG) with highly non-linear chalcogenide material. Square-lattice PCFs show higher dispersion slope that leads to compression of the broadband, thus accumulating more power in the pulse...

  5. Lattice Boltzmann Method Simulation of 3-D Melting Using Double MRT Model with Interfacial Tracking Method

    CERN Document Server

    Li, Zheng; Zhang, Yuwen

    2016-01-01

    Three-dimensional melting problems are investigated numerically with Lattice Boltzmann method (LBM). Regarding algorithm's accuracy and stability, Multiple-Relaxation-Time (MRT) models are employed to simplify the collision term in LBM. Temperature and velocity fields are solved with double distribution functions, respectively. 3-D melting problems are solved with double MRT models for the first time in this article. The key point for the numerical simulation of a melting problem is the methods to obtain the location of the melting front and this article uses interfacial tracking method. The interfacial tracking method combines advantages of both deforming and fixed grid approaches. The location of the melting front was obtained by calculating the energy balance at the solid-liquid interface. Various 3-D conduction controlled melting problems are solved firstly to verify the numerical method. Liquid fraction tendency and temperature distribution obtained from numerical methods agree with the analytical result...

  6. Implementation of 3D Lattice Monte Carlo Simulation on a Cluster of Symmetric Multiprocessors

    Institute of Scientific and Technical Information of China (English)

    雷咏梅; 蒋英; 等

    2002-01-01

    This paper presents a new approach to parallelize 3D lattice Monte Carlo algorithms used in the numerical simulation of polymer on ZiQiang 2000-a cluster of symmetric multiprocessors(SMPs).The combined load for cell and energy calculations over the time step is balanced together to form a single spatial decomposition.Basic aspects and strategies of running Monte Carlo calculations on parallel computers are studied.Different steps involved in porting the software on a parallel architecture based on ZiQiang 2000 running under Linux and MPI are described briefly.It is found that parallelization becomes more advantageous when either the lattice is very large or the model contains many cells and chains.

  7. Variational Monte Carlo study of chiral spin liquid in quantum antiferromagnet on the triangular lattice

    Science.gov (United States)

    Hu, Wen-Jun; Gong, Shou-Shu; Sheng, D. N.

    2016-08-01

    By using Gutzwiller projected fermionic wave functions and variational Monte Carlo technique, we study the spin-1 /2 Heisenberg model with the first-neighbor (J1), second-neighbor (J2), and additional scalar chiral interaction JχSi.(Sj×Sk) on the triangular lattice. In the nonmagnetic phase of the J1-J2 triangular model with 0.08 ≲J2/J1≲0.16 , recent density-matrix renormalization group (DMRG) studies [Zhu and White, Phys. Rev. B 92, 041105(R) (2015), 10.1103/PhysRevB.92.041105 and Hu, Gong, Zhu, and Sheng, Phys. Rev. B 92, 140403(R) (2015), 10.1103/PhysRevB.92.140403] find a possible gapped spin liquid with the signal of a competition between a chiral and a Z2 spin liquid. Motivated by the DMRG results, we consider the chiral interaction JχSi.(Sj×Sk) as a perturbation for this nonmagnetic phase. We find that with growing Jχ, the gapless U(1) Dirac spin liquid, which has the best variational energy for Jχ=0 , exhibits the energy instability towards a gapped spin liquid with nontrivial magnetic fluxes and nonzero chiral order. We calculate topological Chern number and ground-state degeneracy, both of which identify this flux state as the chiral spin liquid with fractionalized Chern number C =1 /2 and twofold topological degeneracy. Our results indicate a positive direction to stabilize a chiral spin liquid near the nonmagnetic phase of the J1-J2 triangular model.

  8. Magnetic properties of two dimensional silicon carbide triangular nanoflakes-based kagome lattices

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaowei [Peking University, Center for Applied Physics and Technology, College of Engineering (China); Zhou Jian [Peking University, Department of Materials Science and Engineering (China); Wang Qian, E-mail: qianwang2@pku.edu.cn [Peking University, Center for Applied Physics and Technology, College of Engineering (China); Jena, Puru [Virginia Commonwealth University, Department of Physics (United States)

    2012-08-15

    Two-dimensional (2D) magnetic kagome lattices are constructed using silicon carbide triangular nanoflakes (SiC-TNFs). Two types of structures with alternating Si and C atoms are studied: the first one is constructed using the C-edged SiC-TNFs as the building blocks and C atoms as the linkers of kagome sites (TNF{sub N}-C-TNF{sub N}) while the second one is composed of the Si-edged SiC-TNFs with Si atoms as linkers (TNF{sub N}-Si-TNF{sub N}). Using density functional theory-based calculations, we show that the fully relaxed TNF{sub N}-C-TNF{sub N} retains the morphology of regular kagome lattice and is ferromagnetism. On the other hand, the TNF{sub N}-Si-TNF{sub N} structure is deformed and antiferromagnetic. However, the ground state of TNF{sub N}-Si-TNF{sub N} structure can be transformed from the antiferromagnetic to ferromagnetic state by applying tensile strain. Monte Carlo simulations indicate that the SiC-TNFs-based kagome lattices can be ferromagnetic at room temperature.

  9. GPU-Accelerated Population Annealing Algorithm: Frustrated Ising Antiferromagnet on the Stacked Triangular Lattice

    Directory of Open Access Journals (Sweden)

    Borovský Michal

    2016-01-01

    Full Text Available The population annealing algorithm is a novel approach to study systems with rough free-energy landscapes, such as spin glasses. It combines the power of simulated annealing, Boltzmann weighted differential reproduction and sequential Monte Carlo process to bring the population of replicas to the equilibrium even in the low-temperature region. Moreover, it provides a very good estimate of the free energy. The fact that population annealing algorithm is performed over a large number of replicas with many spin updates, makes it a good candidate for massive parallelism. We chose the GPU programming using a CUDA implementation to create a highly optimized simulation. It has been previously shown for the frustrated Ising antiferromagnet on the stacked triangular lattice with a ferromagnetic interlayer coupling, that standard Markov Chain Monte Carlo simulations fail to equilibrate at low temperatures due to the effect of kinetic freezing of the ferromagnetically ordered chains. We applied the population annealing to study the case with the isotropic intra- and interlayer antiferromagnetic coupling (J2/|J1| = −1. The reached ground states correspond to non-magnetic degenerate states, where chains are antiferromagnetically ordered, but there is no long-range ordering between them, which is analogical with Wannier phase of the 2D triangular Ising antiferromagnet.

  10. From Discreteness to Continuity: Dislocation Equation for Two-Dimensional Triangular Lattice

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-Feng

    2007-01-01

    @@ A systematic method from the discreteness to the continuity is presented for the dislocation equation of the triangular lattice. A modification of the Peierls equation has been derived strictly. The modified equation includes the higher order corrections of the discrete effect which are important for the core structure of dislocation. It is observed that the modified equation possesses a universal form which is model-independent except the factors.The factors, which depend on the detail of the model, are related to the derivatives of the kernel at its zero point in the wave-vector space. The results open a way to deal with the complicated models because what one needs to do is to investigate the behaviour near the zero point of the kernel in the wave-vector space instead of calculating the kernel completely.

  11. Hydration-induced spin-glass state in a frustrated Na-Mn-O triangular lattice

    Science.gov (United States)

    Bakaimi, Ioanna; Brescia, Rosaria; Brown, Craig M.; Tsirlin, Alexander A.; Green, Mark A.; Lappas, Alexandros

    2016-05-01

    Birnessite compounds are stable across a wide range of compositions that produces a remarkable diversity in their physical, electrochemical, and functional properties. These are hydrated analogs of the magnetically frustrated, mixed-valent manganese oxide structures, with general formula, N axMn O2 . Here we demonstrate that the direct hydration of layered rock-salt type α-NaMn O2 , with the geometrically frustrated triangular lattice topology, yields the birnessite type oxide, N a0.36Mn O2.0.2 H2O , transforming its magnetic properties. This compound has a much-expanded interlayer spacing compared to its parent α-NaMn O2 compound. We show that while the parent α-NaMn O2 possesses a Néel temperature of 45 K as a result of broken symmetry in the M n3 + sublattice, the hydrated derivative undergoes collective spin freezing at 29 K within the M n3 +/M n4 + sublattice. Scaling-law analysis of the frequency dispersion of the ac susceptibility, as well as the temperature-dependent, low-field dc magnetization confirm a cooperative spin-glass state of strongly interacting spins. This is supported by complementary spectroscopic analysis [high-angle annular dark-field scanning transmission electron miscroscopy (TEM), energy-dispersive x-ray spectroscopy, and electron energy-loss spectroscopy] as well as by a structural investigation (high-resolution TEM, x-ray, and neutron powder diffraction) that yield insights into the chemical and atomic structure modifications. We conclude that the spin-glass state in birnessite is driven by the spin frustration imposed by the underlying triangular lattice topology that is further enhanced by the in-plane bond-disorder generated by the mixed-valent character of manganese in the layers.

  12. Tricriticality of the Blume-Emery-Griffiths model in thin films of stacked triangular lattices

    Science.gov (United States)

    El Hog, Sahbi; Diep, H. T.

    2016-03-01

    We study in this paper the Blume-Emery-Griffiths model in a thin film of stacked triangular lattices. The model is described by three parameters: bilinear exchange interaction between spins J, quadratic exchange interaction K and single-ion anisotropy D. The spin Si at the lattice site i takes three values (-1, 0, +1). This model can describe the mixing phase of He-4 (Si = +1,-1) and He-3 (Si = 0) at low temperatures. Using Monte Carlo simulations, we show that there exists a critical value of D below (above) which the transition is of second-(first-)order. In general, the temperature dependence of the concentrations of He-3 is different from layer by layer. At a finite temperature in the superfluid phase, the film surface shows a deficit of He-4 with respect to interior layers. However, effects of surface interaction parameters can reverse this situation. Effects of the film thickness on physical properties will be also shown as functions of temperature.

  13. Superglass Phase of Interaction-Blockaded Gases on a Triangular Lattice

    Science.gov (United States)

    Angelone, Adriano; Mezzacapo, Fabio; Pupillo, Guido

    2016-04-01

    We investigate the quantum phases of monodispersed bosonic gases confined to a triangular lattice and interacting via a class of soft-shoulder potentials. The latter correspond to soft-core potentials with an additional hard-core onsite interaction. Using exact quantum Monte Carlo simulations, we show that the low temperature phases for weak and strong interactions following a temperature quench are a homogeneous superfluid and a glass, respectively. The latter is an insulating phase characterized by inhomogeneity in the density distribution and structural disorder. Remarkably, we find that for intermediate interaction strengths a superglass occurs in an extended region of the phase diagram, where glassy behavior coexists with a sizable finite superfluid fraction. This glass phase is obtained in the absence of geometrical frustration or external disorder and is a result of the competition of quantum fluctuations and cluster formation in the corresponding classical ground state. For high enough temperature, the glass and superglass turn into a floating stripe solid and a supersolid, respectively. Given the simplicity and generality of the model, these phases should be directly relevant for state-of-the-art experiments with Rydberg-dressed atoms in optical lattices.

  14. On entanglement entropy in non-Abelian lattice gauge theory and 3D quantum gravity

    CERN Document Server

    Delcamp, Clement; Riello, Aldo

    2016-01-01

    Entanglement entropy is a valuable tool for characterizing the correlation structure of quantum field theories. When applied to gauge theories, subtleties arise which prevent the factorization of the Hilbert space underlying the notion of entanglement entropy. Borrowing techniques from extended topological field theories, we introduce a new definition of entanglement entropy for both Abelian and non--Abelian gauge theories. Being based on the notion of excitations, it provides a completely relational way of defining regions. Therefore, it naturally applies to background independent theories, e.g. gravity, by circumventing the difficulty of specifying the position of the entangling surface. We relate our construction to earlier proposals and argue that it brings these closer to each other. In particular, it yields the non--Abelian analogue of the `magnetic centre choice', as obtained through an extended--Hilbert--space method, but applied to the recently introduced fusion basis for 3D lattice gauge theories. W...

  15. Spin liquid state in the disordered triangular lattice Sc2Ga2CuO7 revealed by NMR

    Science.gov (United States)

    Khuntia, P.; Kumar, R.; Mahajan, A. V.; Baenitz, M.; Furukawa, Y.

    2016-04-01

    We present microscopic magnetic properties of a two-dimensional triangular lattice Sc2Ga2CuO7 , consisting of single and double triangular Cu planes. An antiferromagnetic (AFM) exchange interaction J /kB≈35 K between Cu2 + (S =1 /2 ) spins in the triangular biplane is obtained from the analysis of intrinsic magnetic susceptibility data. The intrinsic magnetic susceptibility, extracted from 71Ga NMR shift data, displays the presence of AFM short range spin correlations and remains finite down to 50 mK, suggesting a nonsinglet ground state. The nuclear spin-lattice relaxation rate (1 /T1 ) reveals a slowing down of Cu2 + spin fluctuations with decreasing T down to 100 mK. Magnetic specific heat (Cm) and 1 /T1 exhibit power law behavior at low temperatures, implying the gapless nature of the spin excitation spectrum. The absence of long range magnetic ordering down to ˜J /700 , nonzero spin susceptibility at low T , and the power law behavior of Cm and 1 /T1 suggest a gapless quantum spin liquid (QSL) state. Our results demonstrate that persistent spin dynamics induced by frustration maintain a quantum-disordered state at T →0 in this triangular lattice antiferromagnet. This suggests that the low energy modes are dominated by spinon excitations in the QSL state due to randomness engendered by disorder and frustration.

  16. Semiclassical theory of the magnetization process of the triangular lattice Heisenberg model

    Science.gov (United States)

    Coletta, Tommaso; Tóth, Tamás A.; Penc, Karlo; Mila, Frédéric

    2016-08-01

    Motivated by the numerous examples of 1/3 magnetization plateaux in the triangular-lattice Heisenberg antiferromagnet with spins ranging from 1/2 to 5/2, we revisit the semiclassical calculation of the magnetization curve of that model, with the aim of coming up with a simple method that allows one to calculate the full magnetization curve and not just the critical fields of the 1/3 plateau. We show that it is actually possible to calculate the magnetization curve including the first quantum corrections and the appearance of the 1/3 plateau entirely within linear spin-wave theory, with predictions for the critical fields that agree to order 1 /S with those derived a long time ago on the basis of arguments that required going beyond linear spin-wave theory. This calculation relies on the central observation that there is a kink in the semiclassical energy at the field where the classical ground state is the collinear up-up-down structure and that this kink gives rise to a locally linear behavior of the energy with the field when all semiclassical ground states are compared to each other for all fields. The magnetization curves calculated in this way for spin 1/2, 1, and 5/2 are shown to be in good agreement with available experimental data.

  17. TAILORING OF FLATTENED DISPERSION IN TRIANGULAR-LATTICE PHOTONIC CRYSTAL FIBER

    Directory of Open Access Journals (Sweden)

    Sandhir Kumar Singh

    2011-12-01

    Full Text Available The interest of researchers and engineers in several laboratories, since the1980s, has been attracted by the ability to structure materials on the scale of the optical wavelength, a fraction of micrometers or less, in order to develop new optical medium, known as photonic crystals . Photonic crystals rely on a regular morphological microstructure of air-holes, incorporated into the material, which radically alters its optical properties. In Photonic Crystal Fiber (PCF it is possible to realize flat dispersion over a wide wavelength range that cannot be realized with a conventional single-mode fiber. In PCFs, the dispersion can be controlled and tailored with unprecedented freedom. In fact, due to the high refractive index difference between silica and air, and to the flexibility of changing air-hole sizes and patterns, the waveguide contribution to the dispersion parameter can be significantly changed, thus obtaining unusual position of the zero dispersion wavelength, as well as particular values of the dispersion curve slope. In particular, by manipulating the air- hole radius or the lattice period of the micro structured cladding, it is possible to control the zero-dispersion wavelength, which can be tuned over a very wide range, or the dispersion curves, which can be engineered to be ultra flattened. In this paper the geometric parameters of triangular PCF have been properly changed to optimize the dispersion compensation over a wide wavelength range.

  18. Response properties in the adsorption-desorption model on a triangular lattice

    Science.gov (United States)

    Šćepanović, J. R.; Stojiljković, D.; Jakšić, Z. M.; Budinski-Petković, Lj.; Vrhovac, S. B.

    2016-06-01

    The out-of-equilibrium dynamical processes during the reversible random sequential adsorption (RSA) of objects of various shapes on a two-dimensional triangular lattice are studied numerically by means of Monte Carlo simulations. We focused on the influence of the order of symmetry axis of the shape on the response of the reversible RSA model to sudden perturbations of the desorption probability Pd. We provide a detailed discussion of the significance of collective events for governing the time coverage behavior of shapes with different rotational symmetries. We calculate the two-time density-density correlation function C(t ,tw) for various waiting times tw and show that longer memory of the initial state persists for the more symmetrical shapes. Our model displays nonequilibrium dynamical effects such as aging. We find that the correlation function C(t ,tw) for all objects scales as a function of single variable ln(tw) / ln(t) . We also study the short-term memory effects in two-component mixtures of extended objects and give a detailed analysis of the contribution to the densification kinetics coming from each mixture component. We observe the weakening of correlation features for the deposition processes in multicomponent systems.

  19. Quantum Monte Carlo study of long-range transverse-field Ising models on the triangular lattice

    Science.gov (United States)

    Humeniuk, Stephan

    2016-03-01

    Motivated by recent experiments with a Penning ion trap quantum simulator, we perform numerically exact Stochastic Series Expansion quantum Monte Carlo simulations of long-range transverse-field Ising models on a triangular lattice for different decay powers α of the interactions. The phase boundary for the ferromagnet is obtained as a function of α . For antiferromagnetic interactions, there is strong indication that the transverse field stabilizes a clock ordered phase with sublattice magnetization (M ,-M/2 ,-M/2 ) with unsaturated M disorder" similar to the nearest-neighbor antiferromagnet on the triangular lattice. Connecting the known limiting cases of nearest-neighbor and infinite-range interactions, a semiquantitative phase diagram is obtained. Magnetization curves for the ferromagnet for experimentally relevant system sizes and with open boundary conditions are presented.

  20. Exact duality of the dissipative Hofstadter model on a triangular lattice: T-duality and noncommutative algebra

    Science.gov (United States)

    Lee, Taejin

    2016-09-01

    We study the dissipative Hofstadter model on a triangular lattice, making use of the O(2, 2; R) T-dual transformation of string theory. The O(2, 2; R) dual transformation transcribes the model in a commutative basis into the model in a noncommutative basis. In the zero-temperature limit, the model exhibits an exact duality, which identifies equivalent points on the two-dimensional parameter space of the model. The exact duality also defines magic circles on the parameter space, where the model can be mapped onto the boundary sine-Gordon on a triangular lattice. The model describes the junction of three quantum wires in a uniform magnetic field background. An explicit expression of the equivalence relation, which identifies the points on the two-dimensional parameter space of the model by the exact duality, is obtained. It may help us to understand the structure of the phase diagram of the model.

  1. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription

    OpenAIRE

    Weijie Nie; Yuechen Jia; Vázquez de Aldana, Javier R.; Feng Chen

    2016-01-01

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 ×...

  2. A topological semimetal model with f-wave symmetry in a non-Abelian triangular optical lattice

    Science.gov (United States)

    Li, Ling; Bai, Zhiming; Hao, Ningning; Liu, Guocai

    2016-08-01

    We demonstrate that an chiral f-wave topological semimetal can be induced in a non-Abelian triangular optical lattice. We show that the f-wave symmetry topological semimetal is characterized by the topological invariant, i.e., the winding number W, with W=3 and is different from the semimetal with W=1 and 2 which have the p-wave and d-wave symmetry, respectively.

  3. Self-organization of topological defects for a triangular-lattice magnetic dots array subject to a perpendicular magnetic field

    Directory of Open Access Journals (Sweden)

    R.S. Khymyn

    2014-09-01

    Full Text Available The regular array of magnetic particles (magnetic dots of the form of a two-dimensional triangular lattice in the presence of external magnetic field demonstrates complicated magnetic structures. The magnetic symmetry of the ground state for such a system is lower than that for the underlying lattice. Long range dipole-dipole interaction leads to a specific antiferromagnetic order in small fields, whereas a set of linear topological defects appears with the growth of the magnetic field. Self-organization of such defects determines the magnetization process for a system within a wide range of external magnetic fields.

  4. Further Explorations of the Parameter Space of $3D$ Lattice Gauge Theories

    CERN Document Server

    Ferreira, Miguel Jorge Bernabe; Teotonio-Sobrinho, Paulo

    2015-01-01

    State sum models can be used to construct the partition functions of $3D$ lattice gauge theories based on involutory Hopf algebras, $\\mathcal{A}$, of which the group algebras, $\\mathbb{C}G$, are a particular case. Transfer matrices can be obtained from such partition functions by carrying out the state sum construction on a manifold with boundary. The parameter space of these transfer contains various Hamiltonians of physical interest. The $2D$ quantum double Hamitlonians of Kitaev can be obtained from such transfer matrices for specific values of these parameters. A initial study of such models has been carried out in \\cite{p1}. In this paper we study other regions of this parameter space to obtain some new and known models. The new model comprise of Hamiltonians which "partially" confine the excitations of the quantum double Hamiltonians which are usually deconfined. The state sum construction is not invariant by translations and thus it is natural to expect to obtain disordered Hamiltonians from the transf...

  5. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem.

    Science.gov (United States)

    Abas, Aizat; Mokhtar, N Hafizah; Ishak, M H H; Abdullah, M Z; Ho Tian, Ang

    2016-01-01

    This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI). Three different types of Lattice Boltzmann (LB) models are computed, namely, single relaxation time (SRT), multiple relaxation time (MRT), and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV-) based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS) are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required. PMID:27239221

  6. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem

    Directory of Open Access Journals (Sweden)

    Aizat Abas

    2016-01-01

    Full Text Available This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI. Three different types of Lattice Boltzmann (LB models are computed, namely, single relaxation time (SRT, multiple relaxation time (MRT, and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV- based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.

  7. Triangular Spin-Orbit-Coupled Lattice with Strong Coulomb Correlations: Sn Atoms on a SiC(0001) Substrate.

    Science.gov (United States)

    Glass, S; Li, G; Adler, F; Aulbach, J; Fleszar, A; Thomale, R; Hanke, W; Claessen, R; Schäfer, J

    2015-06-19

    Two-dimensional (2D) atom lattices provide model setups with Coulomb correlations that induce competing ground states. Here, SiC emerges as a wide-gap substrate with reduced screening. We report the first artificial high-Z atom lattice on SiC(0001) by Sn adatoms, based on experimental realization and theoretical modeling. Density-functional theory of our triangular structure model closely reproduces the scanning tunneling microscopy. Photoemission data show a deeply gapped state (∼2  eV gap), and, based on our calculations including dynamic mean-field theory, we argue that this reflects a pronounced Mott-insulating scenario. We also find indications that the system is susceptible to antiferromagnetic superstructures. Such artificial lattices on SiC(0001) thus offer a novel platform for coexisting Coulomb correlations and spin-orbit coupling, with bearing for unusual magnetic phases and proposed topological quantum states of matter. PMID:26197013

  8. Competing anisotropies on 3d sub-lattice of YNi4–xCoxB compounds

    International Nuclear Information System (INIS)

    The magnetic anisotropy of 3d sub-lattices has an important rule on the overall magnetic properties of hard magnets. Intermetallics alloys with boron (R-Co/Ni-B, for instance) belong to those hard magnets family and are useful objects to help to understand the magnetic behavior of 3d sub-lattice, specially when the rare earth ions R do not have magnetic nature, like YCo4B ferromagnetic material. Interestingly, YNi4B is a paramagnetic material and Ni ions do not contribute to the magnetic anisotropy. We focused therefore our attention to YNi4–xCoxB series, with x = 0, 1, 2, 3, and 4. The magnetic anisotropy of these compounds is deeper described using statistical and preferential models of Co occupation among the possible Wyckoff positions into the CeCo4B type hexagonal structure. We found that the preferential model is the most suitable to explain the magnetization experimental data

  9. Spin compensation temperature in the Monte Carlo study of a mixed spin-1 and spin-3/2 Ising ferrimagnetic system on the decorated triangular lattice

    Science.gov (United States)

    Masrour, R.; Jabar, A.

    2016-07-01

    Mixed-spin-1 and spin-3/2 Ising model on the decorated triangular lattice is studied by the use of Monte Carlo simulation. Within this approach, the results for the ground-state of the antiferromagnetic and ferromagnetic of decorated triangular lattice are obtained. The reduced transition temperature of each sublattice are obtained. The reduced temperature of compensation is also obtained. The thermal total ratio of magnetic susceptibilities of sublattices is given. The effect of crystal field and exchange interactions on the magnetization of the system are detailed. The magnetic hysteresis cycles are found for different values of exchanges interactions between the same lattice and the two sublattices different, for different crystal filed and temperatures. In addition, very weak exchange interactions and for a higher temperatures and a higher crystal filed values the decorated triangular lattice has been exhibited the superparamagnetic behavior.

  10. Critical frontier of the Potts and percolation models on triangular-type and kagome-type lattices. II. Numerical analysis

    Science.gov (United States)

    Ding, Chengxiang; Fu, Zhe; Guo, Wenan; Wu, F. Y.

    2010-06-01

    In the preceding paper, one of us (F. Y. Wu) considered the Potts model and bond and site percolation on two general classes of two-dimensional lattices, the triangular-type and kagome-type lattices, and obtained closed-form expressions for the critical frontier with applications to various lattice models. For the triangular-type lattices Wu’s result is exact, and for the kagome-type lattices Wu’s expression is under a homogeneity assumption. The purpose of the present paper is twofold: First, an essential step in Wu’s analysis is the derivation of lattice-dependent constants A,B,C for various lattice models, a process which can be tedious. We present here a derivation of these constants for subnet networks using a computer algorithm. Second, by means of a finite-size scaling analysis based on numerical transfer matrix calculations, we deduce critical properties and critical thresholds of various models and assess the accuracy of the homogeneity assumption. Specifically, we analyze the q -state Potts model and the bond percolation on the 3-12 and kagome-type subnet lattices (n×n):(n×n) , n≤4 , for which the exact solution is not known. Our numerical determination of critical properties such as conformal anomaly and magnetic correlation length verifies that the universality principle holds. To calibrate the accuracy of the finite-size procedure, we apply the same numerical analysis to models for which the exact critical frontiers are known. The comparison of numerical and exact results shows that our numerical values are correct within errors of our finite-size analysis, which correspond to 7 or 8 significant digits. This in turn infers that the homogeneity assumption determines critical frontiers with an accuracy of 5 decimal places or higher. Finally, we also obtained the exact percolation thresholds for site percolation on kagome-type subnet lattices (1×1):(n×n) for 1≤n≤6 .

  11. Low-energy effective theories of the two-thirds filled Hubbard model on the triangular necklace lattice

    OpenAIRE

    Janani, C.; Merino, J.; McCulloch, I. P.; Powell, B. J.

    2014-01-01

    Motivated by Mo$_3$S$_7$(dmit)$_3$, we investigate the Hubbard model on the triangular necklace lattice at two-thirds filling. We show, using second order perturbation theory, that in the molecular limit, the ground state and the low energy excitations of this model are identical to those of the spin-one Heisenberg chain. The latter model is known to be in the symmetry protected topological Haldane phase. Away from this limit we show, on the basis of symmetry arguments and density matrix reno...

  12. Detecting the Chern number of topological Weyl semimetals in 3D optical lattices

    Science.gov (United States)

    Zhang, Dan-Wei; Cao, Shuai

    2016-06-01

    We propose a realistic scheme to directly probe the Chern number of topological Weyl semimetals in optical lattices. The Weyl semimetal states can be realized with ultracold fermionic atoms trapped in three-dimensional optical lattices, and are topologically characterized by k z -dependent Chern number, where k z is the out-of-plane quasimomentum. We demonstrate with numerical simulations that this characteristic topological invariant can be extracted from the shift of the hybrid Wannier center in the optical lattice, based on the particle pumping approach. Through in situ measurement of atomic density, the topological properties of the Weyl semimetal states are then directly revealed.

  13. Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3

    Science.gov (United States)

    Nishimoto, Satoshi; Katukuri, Vamshi M.; Yushankhai, Viktor; Stoll, Hermann; Rößler, Ulrich K.; Hozoi, Liviu; Rousochatzakis, Ioannis; van den Brink, Jeroen

    2016-01-01

    Iridium oxides with a honeycomb lattice have been identified as platforms for the much anticipated Kitaev topological spin liquid: the spin-orbit entangled states of Ir4+ in principle generate precisely the required type of anisotropic exchange. However, other magnetic couplings can drive the system away from the spin-liquid phase. With this in mind, here we disentangle the different magnetic interactions in Li2IrO3, a honeycomb iridate with two crystallographically inequivalent sets of adjacent Ir sites. Our ab initio many-body calculations show that, while both Heisenberg and Kitaev nearest-neighbour couplings are present, on one set of Ir-Ir bonds the former dominates, resulting in the formation of spin-triplet dimers. The triplet dimers frame a strongly frustrated triangular lattice and by exact cluster diagonalization we show that they remain protected in a wide region of the phase diagram.

  14. Tight-binding electrons on triangular and kagome lattices under staggered modulated magnetic fields: quantum Hall effects and Hofstadter butterflies

    Energy Technology Data Exchange (ETDEWEB)

    Li Juan; Wang Yifei; Gong Changde, E-mail: yfwang_nju@hotmail.com [Center for Statistical and Theoretical Condensed Matter Physics, and Department of Physics, Zhejiang Normal University, Jinhua 321004 (China)

    2011-04-20

    We consider the tight-binding models of electrons on a two-dimensional triangular lattice and kagome lattice under staggered modulated magnetic fields. Such fields have two components: a uniform-flux part with strength {phi}, and a staggered-flux part with strength {Delta}{phi}. Various properties of the Hall conductances and Hofstadter butterflies are studied. When {phi} is fixed, variation of {Delta}{phi} leads to the quantum Hall transitions and Chern numbers of Landau subbands being redistributed between neighboring pairs. The energy spectra with nonzero {Delta}{phi}s have similar fractal structures but quite different energy gaps compared with the original Hofstadter butterflies of {Delta}{phi} = 0. Moreover, the fan-like structure of Landau levels in the low magnetic field region is also modified appreciably by {Delta}{phi}.

  15. Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3

    Science.gov (United States)

    Nishimoto, Satoshi; Katukuri, Vamshi M.; Yushankhai, Viktor; Stoll, Hermann; Rößler, Ulrich K.; Hozoi, Liviu; Rousochatzakis, Ioannis; van den Brink, Jeroen

    2016-01-01

    Iridium oxides with a honeycomb lattice have been identified as platforms for the much anticipated Kitaev topological spin liquid: the spin-orbit entangled states of Ir4+ in principle generate precisely the required type of anisotropic exchange. However, other magnetic couplings can drive the system away from the spin-liquid phase. With this in mind, here we disentangle the different magnetic interactions in Li2IrO3, a honeycomb iridate with two crystallographically inequivalent sets of adjacent Ir sites. Our ab initio many-body calculations show that, while both Heisenberg and Kitaev nearest-neighbour couplings are present, on one set of Ir–Ir bonds the former dominates, resulting in the formation of spin-triplet dimers. The triplet dimers frame a strongly frustrated triangular lattice and by exact cluster diagonalization we show that they remain protected in a wide region of the phase diagram. PMID:26776664

  16. Lattice Perturbation Theory in Noncommutative Geometry and Parity Anomaly in 3D Noncommutative QED

    CERN Document Server

    Nishimura, J

    2003-01-01

    We formulate lattice perturbation theory for gauge theories in noncommutative geometry. We apply it to three-dimensional noncommutative QED and calculate the effective action induced by Dirac fermions. In particular "parity invariance" of a massless theory receives an anomaly expressed by the noncommutative Chern-Simons action. The coefficient of the anomaly is labelled by an integer depending on the lattice action, which is a noncommutative counterpart of the phenomenon known in the commutative theory. The parity anomaly can also be obtained using Ginsparg-Wilson fermions, where the masslessness is guaranteed at finite lattice spacing. This suggests a natural definition of the lattice-regularized Chern-Simons theory on a noncommutative torus, which could enable nonperturbative studies of quantum Hall systems.

  17. Spin frustration and magnetic ordering in triangular lattice antiferromagnet Ca3CoNb2O9

    Science.gov (United States)

    Dai, Jia; Zhou, Ping; Wang, Peng-Shuai; Pang, Fei; Munsie, Tim J.; Luke, Graeme M.; Zhang, Jin-Shan; Yu, Wei-Qiang

    2015-12-01

    We synthesized a quasi-two-dimensional distorted triangular lattice antiferromagnet Ca3CoNb2O9, in which the effective spin of Co2+ is 1/2 at low temperatures, whose magnetic properties were studied by dc susceptibility and magnetization techniques. The x-ray diffraction confirms the quality of our powder samples. The large Weiss constant θCW˜ -55 K and the low Neel temperature TN˜ 1.45 K give a frustration factor f = | θCW/TN | ≈ 38, suggesting that Ca3CoNb2O9 resides in strong frustration regime. Slightly below TN, deviation between the susceptibility data under zero-field cooling (ZFC) and field cooling (FC) is observed. A new magnetic state with 1/3 of the saturate magnetization Ms is suggested in the magnetization curve at 0.46 K. Our study indicates that Ca3CoNb2O9 is an interesting material to investigate magnetism in triangular lattice antiferromagnets with weak anisotropy. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374364 and 11222433), the National Basic Research Program of China (Grant No. 2011CBA00112). Research at McMaster University supported by the Natural Sciences and Engineering Research Council. Work at North China Electric Power University supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

  18. Jamming and percolation in random sequential adsorption of extended objects on a triangular lattice with quenched impurities

    Science.gov (United States)

    Budinski-Petković, Lj; Lončarević, I.; Jakšić, Z. M.; Vrhovac, S. B.

    2016-05-01

    Random sequential adsorption (RSA) on a triangular lattice with defects is studied by Monte Carlo simulations. The lattice is initially randomly covered by point-like impurities at a certain concentration p. The deposited objects are formed by self-avoiding random walks on the lattice. Jamming coverage {θ\\text{jam}} and percolation threshold θ \\text{p}\\ast are determined for a wide range of impurity concentrations p for various object shapes. Rapidity of the approach to the jamming state is found to be independent on the impurity concentration. The jamming coverage {θ\\text{jam}} decreases with the impurity concentration p and this decrease is more prominent for objects of larger size. For a certain defect concentration, decrease of the jamming coverage with the length of the walk \\ell making the object is found to obey an exponential law, {θ\\text{jam}}={θ0}+{θ1}{{\\text{e}}-\\ell /r} . The results for RSA of polydisperse mixtures of objects of various sizes suggest that, in the presence of impurities, partial jamming coverage of small objects can have even larger values than in the case of an ideal lattice. Percolation in the presence of impurities is also studied and it is found that the percolation threshold θ \\text{p}\\ast is practically insensitive to the concentration of point defects p. Percolation can be reached at highest impurity concentrations with angled objects, and the critical defect concentration p c is lowest for the most compact objects.

  19. Lattice Boltzmann simulation of 2D and 3D non-Brownian suspensions in Couette flow

    NARCIS (Netherlands)

    Kromkamp, J.; Ende, van den D.; Kandhai, D.; Sman, van der R.G.M.; Boom, R.M.

    2006-01-01

    In this study, the Lattice Boltzmann (LB) method is applied for computer simulation of suspension flow in Couette systems. Typical aspects of Couette flow such as wall effects and non-zero Reynolds numbers can be studied well with the LB method because of its time-dependent character. Couette flow o

  20. Coherent addressing of individual neutral atoms in a 3D optical lattice

    CERN Document Server

    Wang, Yang; Corcovilos, Theodore A; Kumar, Aishwarya; Weiss, David S

    2015-01-01

    We demonstrate arbitrary coherent addressing of individual neutral atoms in a $5\\times 5\\times 5$ array formed by an optical lattice. Addressing is accomplished using rapidly reconfigurable crossed laser beams to selectively ac Stark shift target atoms, so that only target atoms are resonant with state-changing microwaves. The effect of these targeted single qubit gates on the quantum information stored in non-targeted atoms is smaller than $3\\times 10^{-3}$ in state fidelity. This is an important step along the path of converting the scalability promise of neutral atoms into reality.

  1. Three-state Potts model on triangular lattice with nearest-neighbor and next-nearest-neighbor antiferromagnetic interactions

    Science.gov (United States)

    Murtazaev, Akai K.; Babaev, Albert B.; Magomedov, Magomed A.; Kassan-Ogly, Felix A.; Proshkin, Alexey I.

    2016-11-01

    Using Monte Carlo simulations, we investigated phase transitions and frustrations in the three-state Potts model on a triangular lattice with allowance for antiferromagnetic exchange interactions between nearest-neighbors J1 and next-nearest-neighbors J2. The ratio of the next-nearest-neighbor and nearest-neighbor exchange constants r=J2/J1 is chosen within the range of 0≤r≤2. Based on the analysis of the entropy, specific heat, system state density function, and fourth order Binder cumulants, the phase transitions in the Potts model with interactions J1<0 and J2<0 are shown to be found in value ranges of 0≤r<0.2 and 1.25≤r≤2.0. In an intermediate range of 0.2≤r≤1.0 the phase transition fails and the frustrations are revealed.

  2. Effective properties of a new auxetic triangular lattice: an analytical approach

    Directory of Open Access Journals (Sweden)

    L. Cabras

    2014-07-01

    Full Text Available In this article we propose a new auxetic periodic lattice with negative Poisson's ratio which tends to the limit ν=-1 under particular conditions. We have studied its generation and kinematic, and we give a full description of the mechanical properties of this innovative model. Calibrating the geometrical configuration of the lattice and the mechanical properties of the constituent material we are able to have a Poisson's ratio which is arbitrarily close to -1.

  3. Protein folding optimization based on 3D off-lattice model via an improved artificial bee colony algorithm.

    Science.gov (United States)

    Li, Bai; Lin, Mu; Liu, Qiao; Li, Ya; Zhou, Changjun

    2015-10-01

    Protein folding is a fundamental topic in molecular biology. Conventional experimental techniques for protein structure identification or protein folding recognition require strict laboratory requirements and heavy operating burdens, which have largely limited their applications. Alternatively, computer-aided techniques have been developed to optimize protein structures or to predict the protein folding process. In this paper, we utilize a 3D off-lattice model to describe the original protein folding scheme as a simplified energy-optimal numerical problem, where all types of amino acid residues are binarized into hydrophobic and hydrophilic ones. We apply a balance-evolution artificial bee colony (BE-ABC) algorithm as the minimization solver, which is featured by the adaptive adjustment of search intensity to cater for the varying needs during the entire optimization process. In this work, we establish a benchmark case set with 13 real protein sequences from the Protein Data Bank database and evaluate the convergence performance of BE-ABC algorithm through strict comparisons with several state-of-the-art ABC variants in short-term numerical experiments. Besides that, our obtained best-so-far protein structures are compared to the ones in comprehensive previous literature. This study also provides preliminary insights into how artificial intelligence techniques can be applied to reveal the dynamics of protein folding. Graphical Abstract Protein folding optimization using 3D off-lattice model and advanced optimization techniques.

  4. The Critical Lines of the Yang-Lee Edge Singularities of the Anisotropic Ising Ferromagnets on Square, Triangular and Honeycomb Lattices

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-Zhi

    2001-01-01

    Using the numerical results and some results from the renormalization group theory, we extend our previous approach of determining the Yang-Lee edge singularities of Ising ferromagnets on square, triangular and honeycomb lattices (Phys. Rev. Lett. 78 (1997) 413; Phys. Rev. E56 (1998) 2793; E57 (1998) 5013) and obtain accurate closed-form approximations of the critical lines of anisotropic Ising ferromagnets on these lattices.

  5. The calculation of the band structure in 3D phononic crystal with hexagonal lattice

    Energy Technology Data Exchange (ETDEWEB)

    Aryadoust, Mahrokh; Salehi, H. [University of Shahid Chamran, Ahvaz (Iran, Islamic Republic of). Dept. of Physics

    2015-07-01

    In this article, the propagation of acoustic waves in the phononic crystals (PCs) of three dimensions with the hexagonal (HEX) lattice is studied theoretically. The PCs are constituted of nickel (Ni) spheres embedded in epoxy. The calculations of the band structure and the density of states are performed using the plane wave expansion (PWE) method in the irreducible part of the Brillouin zone (BZ). In this study, we analyse the dependence of the band structures inside (the complete band gap width) on c/a and filling fraction in the irreducible part of the first BZ. Also, we have analysed the band structure of the ALHA and MLHKM planes. The results show that the maximum width of absolute elastic band gap (AEBG) (0.045) in the irreducible part of the BZ of HEX lattice is formed for c/a=6 and filling fraction equal to 0.01. In addition, the maximum of the first and second AEBG widths are 0.0884 and 0.0474, respectively, in the MLHKM plane, and the maximum of the first and second AEBG widths are 0.0851 and 0.0431, respectively, in the ALHA plane.

  6. Design of a Photonic-Crystal Channel-Drop Filter Based on the Two-Dimensional Triangular-Lattice Hole Structure

    Institute of Scientific and Technical Information of China (English)

    Kyu; Hwan; Hwang; G.; Hugh; Song; Chanmook; Lim; Soan; Kim; Kyung-Won; Chun; Mahn; Yong; Park

    2003-01-01

    A channel-drop filter has been designed based on the two-dimensional triangular-lattice hole photonic-crystal structure, which consists of two line defects and two point defects, by a two-dimensional finite-difference time-domain simulation.

  7. Dual FIB-SEM 3D Imaging and Lattice Boltzmann Modeling of Porosimetry and Multiphase Flow in Chalk

    Science.gov (United States)

    Rinehart, A. J.; Yoon, H.; Dewers, T. A.; Heath, J. E.; Petrusak, R.

    2010-12-01

    Mercury intrusion porosimetry (MIP) is an often-applied technique for determining pore throat distributions and seal analysis of fine-grained rocks. Due to closure effects, potential pore collapse, and complex pore network topologies, MIP data interpretation can be ambiguous, and often biased toward smaller pores in the distribution. We apply 3D imaging techniques and lattice-Boltzmann modeling in interpreting MIP data for samples of the Cretaceous Selma Group Chalk. In the Mississippi Interior Salt Basin, the Selma Chalk is the apparent seal for oil and gas fields in the underlying Eutaw Fm., and, where unfractured, the Selma Chalk is one of the regional-scale seals identified by the Southeast Regional Carbon Sequestration Partnership for CO2 injection sites. Dual focused ion - scanning electron beam and laser scanning confocal microscopy methods are used for 3D imaging of nanometer-to-micron scale microcrack and pore distributions in the Selma Chalk. A combination of image analysis software is used to obtain geometric pore body and throat distributions and other topological properties, which are compared to MIP results. 3D data sets of pore-microfracture networks are used in Lattice Boltzmann simulations of drainage (wetting fluid displaced by non-wetting fluid via the Shan-Chen algorithm), which in turn are used to model MIP procedures. Results are used in interpreting MIP results, understanding microfracture-matrix interaction during multiphase flow, and seal analysis for underground CO2 storage. This work was supported by the US Department of Energy, Office of Basic Energy Sciences as part of an Energy Frontier Research Center. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. The cone phase of liquid crystals: Triangular lattice of double-tilt cylinders

    Indian Academy of Sciences (India)

    Yashodhan Hatwalne; N V Madhusudana

    2003-08-01

    We predict the existence of a new defect-lattice phase near the nematic–smectic-C (NC) transition. This tilt-analogue of the blue phase is a lattice of double-tilt cylinders which are disclination lines in the smectic layer normal as well as the c-field. We discuss the structure and stability of the cone phase. We suggest that many ‘nematics’ exhibiting short range layering and tilt order may in fact be in the molten cone phase, which is a line liquid.

  9. Chiral Spin Liquids in Triangular-Lattice SU (N ) Fermionic Mott Insulators with Artificial Gauge Fields

    Science.gov (United States)

    Nataf, Pierre; Lajkó, Miklós; Wietek, Alexander; Penc, Karlo; Mila, Frédéric; Läuchli, Andreas M.

    2016-10-01

    We show that, in the presence of a π /2 artificial gauge field per plaquette, Mott insulating phases of ultracold fermions with SU (N ) symmetry and one particle per site generically possess an extended chiral phase with intrinsic topological order characterized by an approximate ground space of N low-lying singlets for periodic boundary conditions, and by chiral edge states described by the SU(N ) 1 Wess-Zumino-Novikov-Witten conformal field theory for open boundary conditions. This has been achieved by extensive exact diagonalizations for N between 3 and 9, and by a parton construction based on a set of N Gutzwiller projected fermionic wave functions with flux π /N per triangular plaquette. Experimental implications are briefly discussed.

  10. 3D analysis, modeling and simulation of transport processes in compressed fibrous microstructures, using the Lattice Boltzmann method

    International Nuclear Information System (INIS)

    In this paper we combine a stochastic 3D microstructure model of a fiber based gas diffusion layer of polymer electrolyte fuel cells with a Lattice Boltzmann model for fluid transport. We focus on a simple approach of compressing the planar oriented virtual geometry of paper-type gas diffusion layer from Toray. Material parameters – permeability and tortuosity – are calculated from simulation of one phase, one component gas flow in stochastic geometries. We analyze the statistical spread of simulation results on ensembles of the virtual geometry, both uncompressed and compressed. The influence of the compression is discussed with regard to the Kozeny–Carman equation. The effective transport properties calculated from transport simulations in compressed gas diffusion layers agree well with a trend based on the Kozeny–Carman equation

  11. Micro-Macro Scale Mixing Interactions by Intestinal Villi Enhance Absorption: a 3D Lattice-Boltzmann Model

    Science.gov (United States)

    Wang, Yanxing; Brasseur, James; Banco, Gino

    2010-11-01

    Muscle-induced villi motions may create a micro-scale flow that couples with a lumen-scale macro flow to enhance nutrient transport and absorption in the intestine. Using a 3D multiscale lattice Boltzmann model of a lid-driven cavity flow with microscale 3-D leaf and finger-like villi in pendular motion at the lower surface, we analyze the coupling between micro and macro-scale nutrient mixing and absorption at the villi surfaces. RESULTS: The villi motions enhance absorption by creating a micro-mixing layer (MML) that pumps low concentration fluid from between villi groups and attracts fluid with high concentration from the macro flow. The MML couples with the macro flow via a diffusion layer. Leaf-like villi create the strongest MML and, consequently, the highest absorption rates. The finger-like villi create a weaker MML due to the existence of flow between villi. The strength of the MML and nutrient absorption increases with villus frequency. The absorption rate also increases with villus length; however the simulations predict an optimal length close to the physiological length of villi in humans. The complex flow structure will be discussed. We conclude that the interaction between micro-scale villi-induced fluid motions and macro-scale motility-induced flow may play a significant role in intestinal absorption. Supported by NSF Grant CTS-056215.

  12. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.

    Science.gov (United States)

    Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng

    2016-01-01

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions. PMID:26924255

  13. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.

    Science.gov (United States)

    Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng

    2016-02-29

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.

  14. Commensurate and incommensurate magnetic order in spin-1 chains stacked on the triangular lattice in Li2NiW2O8

    Science.gov (United States)

    Ranjith, K. M.; Nath, R.; Majumder, M.; Kasinathan, D.; Skoulatos, M.; Keller, L.; Skourski, Y.; Baenitz, M.; Tsirlin, A. A.

    2016-07-01

    We report the thermodynamic properties, magnetic ground state, and microscopic magnetic model of the spin-1 frustrated antiferromagnet Li2NiW2O8 , showing successive transitions at TN 1≃18 K and TN 2≃12.5 K in zero field. Nuclear magnetic resonance and neutron diffraction reveal collinear and commensurate magnetic order with the propagation vector k =(1/2 ,0 ,1/2 ) below TN 2. The ordered moment of 1.8 μB at 1.5 K is directed along [0.89 (9 ),-0.10 (5 ),-0.49 (6 )] and matches the magnetic easy axis of spin-1 Ni2 + ions, which is determined by the scissor-like distortion of the NiO6 octahedra. Incommensurate magnetic order, presumably of spin-density-wave type, is observed in the region between TN 2 and TN 1. Density-functional band-structure calculations put forward a three-dimensional spin lattice with spin-1 chains running along the [01 1 ¯] direction and stacked on a spatially anisotropic triangular lattice in the a b plane. We show that the collinear magnetic order in Li2NiW2O8 is incompatible with the triangular lattice geometry and thus driven by a pronounced easy-axis single-ion anisotropy of Ni2 +.

  15. Phase structure of 3D Z(N lattice gauge theories at finite temperature: Large-N and continuum limits

    Directory of Open Access Journals (Sweden)

    O. Borisenko

    2014-11-01

    Full Text Available We study numerically three-dimensional Z(N lattice gauge theories at finite temperature, for N=5,6,8,12,13 and 20 on lattices with temporal extension Nt=2,4,8. For each model, we locate phase transition points and determine critical indices. We propose also the scaling of critical points with N. The data obtained enable us to verify the scaling near the continuum limit for the Z(N models at finite temperatures.

  16. On triangular algebras with noncommutative diagonals

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We construct a triangular algebra whose diagonals form a noncommutative algebra and its lattice of invariant projections contains only two nontrivial projections. Moreover we prove that our triangular algebra is maximal.

  17. Static and dynamical spin correlations of the S =1/2 random-bond antiferromagnetic Heisenberg model on the triangular and kagome lattices

    Science.gov (United States)

    Shimokawa, Tokuro; Watanabe, Ken; Kawamura, Hikaru

    2015-10-01

    Inspired by the recent theoretical suggestion that the random-bond S =1 /2 antiferromagnetic Heisenberg model on the triangular and the kagome lattices might exhibit a randomness-induced quantum spin liquid (QSL) behavior when the strength of the randomness exceeds a critical value, and that this "random-singlet state" might be relevant to the QSL behaviors experimentally observed in triangular organic salts κ -(ET) 2Cu2(CN) 3 and EtMe3Sb [Pd(dmit)2] 2 and in kagome herbertsmithite ZnCu3(OH) 6Cl2 , we further investigate the nature of the static and the dynamical spin correlations of these models. We compute the static and the dynamical spin structure factors, S (q ) and S (q ,ω ) , by means of an exact diagonalization method. In both triangular and kagome models, the computed S (q ,ω ) in the random-singlet state depends on the wave vector q only weakly, robustly exhibiting gapless behaviors accompanied by the broad distribution extending to higher energy ω . Especially in the strongly random kagome model, S (q ,ω ) hardly depends on q , and exhibits an almost flat distribution for a wide range of ω , together with a ω =0 peak. These features agree semiquantitatively with the recent neutron-scattering data on a single-crystal herbertsmithite. Furthermore, the computed magnetization curve agrees almost quantitatively with the experimental one recently measured on a single-crystal herbertsmithite. These results suggest that the QSL state observed in herbertsmithite might indeed be the randomness-induced QSL state, i.e., the random-singlet state.

  18. Deconfinement and universality in the 3D U(1) lattice gauge theory at finite temperature: study in the dual formulation

    CERN Document Server

    Borisenko, Oleg; Gravina, Mario; Papa, Alessandro

    2015-01-01

    We study analytically and numerically the three-dimensional U(1) lattice gauge theory at finite temperature in the dual formulation. For an appropriate disorder operator, we obtain the renormalization group equations describing the critical behavior of the model in the vicinity of the deconfinement phase transition. These equations are used to check the validity of the Svetitsky-Yaffe conjecture regarding the critical behavior of the lattice U(1) model. Furthermore, we perform numerical simulations of the model for $N_t = 1, 2, 4, 8$ and compute, by a cluster algorithm, the dual correlation functions and the corresponding second moment correlation length. In this way we locate the position of the critical point and calculate critical indices.

  19. Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice κ -(ET )2Ag2 (CN )3

    Science.gov (United States)

    Shimizu, Yasuhiro; Hiramatsu, Takaaki; Maesato, Mitsuhiko; Otsuka, Akihiro; Yamochi, Hideki; Ono, Akihiro; Itoh, Masayuki; Yoshida, Makoto; Takigawa, Masashi; Yoshida, Yukihiro; Saito, Gunzi

    2016-09-01

    The effects of pressure on a quantum spin liquid are investigated in an organic Mott insulator κ -(ET )2Ag2 (CN )3 with a spin-1 /2 triangular lattice. The application of negative chemical pressure to κ -(ET )2Cu2 (CN )3 , which is a well-known sister Mott insulator, allows for extensive tuning of antiferromagnetic exchange coupling, with J /kB=175 - 310 K , under hydrostatic pressure. Based on 13C nuclear magnetic resonance measurements under pressure, we uncover universal scaling in the static and dynamic spin susceptibilities down to low temperatures ˜0.1 kBT /J . The persistent fluctuations and residual specific heat coefficient are consistent with the presence of gapless low-lying excitations. Our results thus demonstrate the fundamental finite-temperature properties of a quantum spin liquid in a wide parameter range.

  20. Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice κ-(ET)_{2}Ag_{2}(CN)_{3}.

    Science.gov (United States)

    Shimizu, Yasuhiro; Hiramatsu, Takaaki; Maesato, Mitsuhiko; Otsuka, Akihiro; Yamochi, Hideki; Ono, Akihiro; Itoh, Masayuki; Yoshida, Makoto; Takigawa, Masashi; Yoshida, Yukihiro; Saito, Gunzi

    2016-09-01

    The effects of pressure on a quantum spin liquid are investigated in an organic Mott insulator κ-(ET)_{2}Ag_{2}(CN)_{3} with a spin-1/2 triangular lattice. The application of negative chemical pressure to κ-(ET)_{2}Cu_{2}(CN)_{3}, which is a well-known sister Mott insulator, allows for extensive tuning of antiferromagnetic exchange coupling, with J/k_{B}=175-310  K, under hydrostatic pressure. Based on ^{13}C nuclear magnetic resonance measurements under pressure, we uncover universal scaling in the static and dynamic spin susceptibilities down to low temperatures ∼0.1k_{B}T/J. The persistent fluctuations and residual specific heat coefficient are consistent with the presence of gapless low-lying excitations. Our results thus demonstrate the fundamental finite-temperature properties of a quantum spin liquid in a wide parameter range. PMID:27636491

  1. Effect of super-exchange interaction on ground state magnetic properties of spin-dependent Falicov-Kimball model on a triangular lattice

    International Nuclear Information System (INIS)

    Ground state magnetic properties are studied by incorporating the super-exchange interaction (Jse) in the spin-dependent Falicov-Kimball model (FKM) between localized (f-) electrons on a triangular lattice for half filled case. Numerical diagonalization and Monte-Carlo simulation are used to study the ground state magnetic properties. We have found that the magnetic moment of (d-) and (f-) electrons strongly depend on the value of Hund’s exchange (J), super-exchange interaction (Jse) and also depends on the number of (d-) electrons (Nd). The ground state changes from antiferromagnetic (AFM) to ferromagnetic (FM) state as we decrease (Nd). Also the density of d electrons at each site depends on the value of J and Jse

  2. Competing anisotropies on 3d sub-lattice of YNi{sub 4–x}Co{sub x}B compounds

    Energy Technology Data Exchange (ETDEWEB)

    Caraballo Vivas, R. J.; Rocco, D. L.; Reis, M. S. [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, 24210-346 Niterói, RJ (Brazil); Costa Soares, T. [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, 24210-346 Niterói, RJ (Brazil); IF Sudeste MG Campus de Juiz de Fora-Núcleo de Física, 36080-001 Juiz de Fora, MG (Brazil); Caldeira, L. [IF Sudeste MG Campus de Juiz de Fora-Núcleo de Física, 36080-001 Juiz de Fora, MG (Brazil); Coelho, A. A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas-Unicamp, Caixa postal 6165, 13083-859 Campinas, SP (Brazil)

    2014-08-14

    The magnetic anisotropy of 3d sub-lattices has an important rule on the overall magnetic properties of hard magnets. Intermetallics alloys with boron (R-Co/Ni-B, for instance) belong to those hard magnets family and are useful objects to help to understand the magnetic behavior of 3d sub-lattice, specially when the rare earth ions R do not have magnetic nature, like YCo{sub 4}B ferromagnetic material. Interestingly, YNi{sub 4}B is a paramagnetic material and Ni ions do not contribute to the magnetic anisotropy. We focused therefore our attention to YNi{sub 4–x}Co{sub x}B series, with x = 0, 1, 2, 3, and 4. The magnetic anisotropy of these compounds is deeper described using statistical and preferential models of Co occupation among the possible Wyckoff positions into the CeCo{sub 4}B type hexagonal structure. We found that the preferential model is the most suitable to explain the magnetization experimental data.

  3. Monte Carlo simulations on magnetic behavior of a spin-chain system in triangular lattice doped with antiferromagnetic bonds

    Institute of Scientific and Technical Information of China (English)

    YAO Xiao-yan; LI Peng-lei; DONG Shuai; LIU Jun-ming

    2007-01-01

    A three-dimensional Ising-like model doped with anti-ferromagnetic (AFM) bonds is proposed to investigate the magnetic properties of a doped triangular spin-chain system by using a Monte-Carlo simulation. The simulated results indicate that a steplike magnetization behavior is very sensitive to the concentration of AFM bonds. A low concentration of AFM bonds can suppress the stepwise behavior considerably, in accordance with doping experiments on Ca3Co206. The analysis of spin snapshots demonstrates that the AFM bond doping not only breaks the ferromagnetic ordered linear spin chains along the hexagonal c-axis but also has a great influence upon the spin configuration in the ab-plane.

  4. An algorithm for high order strong coupling expansions: The mass gap in 3d pure Z2 lattice gauge theory

    International Nuclear Information System (INIS)

    An efficient description of all clusters contributing to the strong coupling expansion of the mass gap in three-dimensional pure Z2 lattice gauge theory is presented. This description is correct to all orders in the strong coupling expansion and is chosen in such a way that it remains valid in four dimensions for gauge group Z2. Relying on this description an algorithm has been constructed which generates and processes all the contributing graphs to the exact strong coupling expansion of the mass gap in the three-dimensional model in a fully automatic fashion. A major component of this algorithm can also be used to generate exact strong coupling expansions for the free energy logZ. The algorithm is correct to any order; thus the order of these expansions is only limited by the available computing power. The presentation of the algorithm is such that it can serve as a guide-line for the construction of a generalized one which would also generate exact strong coupling expansions for the masses of low-lying excited states of four-dimensional pure Yang-Mills theories. (orig.)

  5. Exchange coupling and helical spin order in the triangular lattice antiferromagnet CuCrO2 using first principles

    Institute of Scientific and Technical Information of China (English)

    Jiang Xue-Fan; Liu Xian-Feng; Wu Yin-Zhong; Han Jiu-Rong

    2012-01-01

    The magnetic and electronic properties of the geometrically frustrated triangular antiferromagnet CuCrO2 are investigated by first principles through density functional theory calculations within the generalized gradient approximations (GGA)+U scheme.The spin exchange interactions up to the third nearest neighbours in the ab plane as well as the coupling between adjacent layers are calculated to examine the magnetism and spin frustration.It is found that CuCrO2 has a natural two-dimensional characteristic of the magnetic interaction.Using Monte-Carlo simulation,we obtain the Néel temperature to be 29.9 K,which accords well with the experimental value of 24 K.Based on noncollinear magnetic structure calculations,we verify that the incommensurate spiral-spin structure with (110) spiral plane is believable for the magnetic ground state,which is consistent with the experimental observations.Due to intra-layer geometric spin frustration,parallel helical-spin chains arise along the a,b,or a + b directions,each with a screw-rotation angle of about 120°.Our calculations of the density of states show that the spin frustration plays an important role in the change of d-p hybridization,while the spin-orbit coupling has a very limited influence on the electronic structure.

  6. A simulation study of microwave field effects on a 3D orthorhombic lattice of rotating dipoles: short-range potential energy variation

    Science.gov (United States)

    Kapranov, Sergey V.; Kouzaev, Guennadi A.

    2016-05-01

    Variation of the short-range potential energy of interaction of nearest dipoles in a three-dimensional (3D) orthorhombic lattice exposed to microwave electric fields is studied by means of the Langevin dynamics simulations. The global increase of the mean potential energy is typical for all the frequencies and intensities at lower temperatures, whereas separate potential energy peaks or peak chains are observed at intermediate temperatures. A simple statistical model proposed to account for the temperature dependence of the field intensity for potential energy peaks suggests the concerted collective rotation of the dipoles. The temperature dependence of the peak frequency is explained using a combination of the one-dimensional Kramers and the resonant activation theories applied to the field-driven collective rotation, with the nearly degenerate angular coordinates of the dipoles being used as a single effective coordinate.

  7. Magnetic order and glassiness in distorted triangular lattice materials, Cu2 (1 - x) Zn 2x(OH)3 NO 3/(C 7 H 15COO)

    Science.gov (United States)

    Wu, Jian; Werner, Fletcher; Wildeboer, Julia S.; Seidel, Alexander; Nussinov, Zohar; Solin, S. A.

    2011-03-01

    We discuss the magnetic properties of a class of spin S = 1 / 2 antiferromagnetic quasi-triangular lattice materials, both in the clean limit and in the presence of non-magnetic Zn impurities. These systems are long organic chain intercalated derivatives of copper hydroxy nitrate, with a very large c-axis separation of 24Å. In these compounds, we find that a spin glass phase is universally preceded by two different power law regimes in the temperature dependence of the DC magnetic susceptibility, separated by a sharp crossover. This is seen both in the presence as well as in the absence of non-magnetic Zn impurities, where the power law exponents are surprisingly unperturbed by the compositional disorder. We argue that these findings may be consistent with a picture based on a self-generated spin glass in the clean undoped compound, where frustration is the driving mechanism of the glassiness rather than disorder. While AC measurements and time dependent magnetization follow traditional spin glass paradigms, the power law structure found in the DC susceptibility is argued to deviate in various ways from scenarios expected based on Griffiths type physics, and may call for new explanations.

  8. Nano-spatial parameters from 3D to 2D lattice dimensionality by organic variant in [ZnCl4]- [R]+ hybrid materials: Structure, architecture-lattice dimensionality, microscopy, optical Eg and PL correlations

    Science.gov (United States)

    Kumar, Ajit; Verma, Sanjay K.; Alvi, P. A.; Jasrotia, Dinesh

    2016-04-01

    The nanospatial morphological features of [ZnCl]- [C5H4NCH3]+ hybrid derivative depicts 28 nm granular size and 3D spreader shape packing pattern as analyzed by FESEM and single crystal XRD structural studies. The organic moiety connect the inorganic components through N-H+…Cl- hydrogen bond to form a hybrid composite, the replacement of organic derivatives from 2-methylpyridine to 2-Amino-5-choloropyridine results the increase in granular size from 28nm to 60nm and unit cell packing pattern from 3D-2D lattice dimensionality along ac plane. The change in optical energy direct band gap value from 3.01eV for [ZnCl]- [C5H4NCH3]+ (HM1) to 3.42eV for [ZnCl]- [C5H5ClN2]+ (HM2) indicates the role of organic moiety in optical properties of hybrid materials. The photoluminescence emission spectra is observed in the wavelength range of 370 to 600 nm with maximum peak intensity of 9.66a.u. at 438 nm for (HM1) and 370 to 600 nm with max peak intensity of 9.91 a.u. at 442 nm for (HM2), indicating that the emission spectra lies in visible range. PL excitation spectra depicts the maximum excitation intensity [9.8] at 245.5 nm for (HM1) and its value of 9.9 a.u. at 294 nm, specify the excitation spectra lies in UV range. Photoluminescence excitation spectra is observed in the wavelength range of 280 to 350 nm with maximum peak intensity of 9.4 a.u. at 285.5 nm and 9.9 a.u. at 294 and 297 nm, indicating excitation in the UV spectrum. Single crystal growth process and detailed physiochemical characterization such as XRD, FESEM image analysis photoluminescence property reveals the structure stability with non-covalent interactions, lattice dimensionality (3D-2D) correlations interweaving into the design of inorganic-organic hybrid materials.

  9. Parameterization for fitting triangular mesh

    Institute of Scientific and Technical Information of China (English)

    LIN Hongwei; WANG Guojin; LIU Ligang; BAO Hujun

    2006-01-01

    In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.

  10. Coupling between the charge carriers and lattice distortions via modulation of the orbital angular momentum m sub l =0 of the 3d holes by polarized XAS spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pompa, M.; Turtu, S.; Campanella, F.; Pettiti, I.; Udron, D. (INFM, Dipt. di Fisica, Rome-1 Univ. (Italy)); Bianconi, A. (INFM, Dipt. di Fisica, Rome-1 Univ. (Italy) Univ. of L' Aquila (Italy)); Flank, A.M.; Lagarde, P. (LURE, 91 - Orsay (France)); Li, C. (Inst. of Physics, Academia Sinica, Beijing (China))

    1991-12-01

    The change of the orbital angular momentum m{sub l} of the Cu 3d holes going from the insulating to the metallic phase has been studied in several families of high Tc superconductors. The symmetry of the 3d{sup 9}L states in the metallic phase has been studied by quantitative analysis of the variation of polarized Cu L{sub 3} X-ray absorption spectra. At a doping level n{sub h} {approx equal} 15% we have found 10% of Zhang-Rice singlets 3d{sub x}2{sub -y}2 L(b{sub 1}) and 5% of 3d{sub 3z}2{sub -r}2L(a{sub 1}) states. Therefore the percentage of the 3d{sub 3z}2{sub -r}2L states on the total number of the 3d{sup 9}L states is about 30% i.e. much larger than the probability of single hole states 3d{sub 3z}2{sub -r}2 in the insulating phase. The EXAFS and XANES studies of the Cu site structure and dynamics in Bi{sub 2}Sr{sub 2}Ca{sub 1-x}Y{sub x}Cu{sub 2}O{sub {proportional to}} {sub 8} system point toward the coupling of the charge carriers with distortions of the Cu sites driven by the m{sub l}=0 character of the Cu 3d holes that can be called a 3d{sub z}2{sub -r}2 polaron. (orig.).

  11. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    Science.gov (United States)

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  12. Ryukyu Subduction Zone: 3D Geodynamic Simulations of the Effects of Slab Shape and Depth on Lattice-Preferred Orientation (LPO) and Seismic Anisotropy

    Science.gov (United States)

    Tarlow, S.; Tan, E.; Billen, M. I.

    2015-12-01

    At the Ryukyu subduction zone, seismic anisotropy observations suggest that there may be strong trench-parallel flow within the mantle wedge driven by complex 3D slab geometry. However, previous simulations have either failed to account for 3D flow or used the infinite strain axis (ISA) approximation for LPO, which is known to be inaccurate in complex flow fields. Additionally, both the slab depth and shape of the Ryukyu slab are contentious. Development of strong trench-parallel flow requires low viscosity to decouple the mantle wedge from entrainment by the sinking slab. Therefore, understanding the relationship between seismic anisotropy and the accompanying flow field will better constrain the material and dynamic properties of the mantle near subduction zones. In this study, we integrate a kinematic model for calculation of LPO (D-Rex) into a buoyancy-driven, instantaneous 3D flow simulation (ASPECT), using composite non-Newtonian rheology to investigate the dependence of LPO on slab geometry and depth at the Ryukyu Trench. To incorporate the 3D flow effects, the trench and slab extends from the southern tip of Japan to the western edge of Taiwan and the model region is approximately 1/4 of a spherical shell extending from the surface to the core-mantle boundary. In the southern-most region we vary the slab depth and shape to test for the effects of the uncertainties in the observations. We also investigate the effect of adding locally hydrated regions above the slab that affect both the mantle rheology and development of LPO through the consequent changes in mantle flow and dominate (weakest) slip system. We characterize how changes in the simulation conditions affect the LPO within the mantle wedge, subducting slab and sub-slab mantle and relate these to surface observations of seismic anisotropy.

  13. Implementation of 3D Lattice Monte Carlo Simulation on a Cluster of Symmetric Multiprocessors%基于集群系统的3D格点Monte Carlo算法并行实现

    Institute of Scientific and Technical Information of China (English)

    雷咏梅; 蒋英; 冯捷

    2002-01-01

    This paper presents a new approach to parallelize 3D lattice Monte Carlo algorithms used in the numerical simulation of polymer on ZiQiang 2000-a cluster of symmetric multiprocessors (SMPs). The combined load for cell and energy calculations over the time step is balanced together to form a single spatial decomposition. Basic aspects and strategies of running Monte Carlo calculations on parallel computers are studied. Different steps involved in porting the software on a parallel architecture based on ZiQiang 2000 running under Linux and MPI are described briefly. It is found that parallelization becomes more advantageous when either the lattice is very large or the model contains many cells and chains.

  14. Combinatorial 3D Mechanical Metamaterials

    Science.gov (United States)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  15. Simultaneous triangularization

    CERN Document Server

    Radjavi, Heydar

    2000-01-01

    A collection of matrices is said to be triangularizable if there is an invertible matrix S such that S1 AS is upper triangular for every A in the collection. This generalization of commutativity is the subject of many classical theorems due to Engel, Kolchin, Kaplansky, McCoy and others. The concept has been extended to collections of bounded linear operators on Banach spaces: such a collection is defined to be triangularizable if there is a maximal chain of subspaces of the Banach space, each of which is invariant under every member of the collection. Most of the classical results have been generalized to compact operators, and there are also recent theorems in the finite-dimensional case. This book is the first comprehensive treatment of triangularizability in both the finite and infinite-dimensional cases. It contains numerous very recent results and new proofs of many of the classical theorems. It provides a thorough background for research in both the linear-algebraic and operator-theoretic aspects of tr...

  16. 3D Framework DNA Origami with Layered Crossovers.

    Science.gov (United States)

    Hong, Fan; Jiang, Shuoxing; Wang, Tong; Liu, Yan; Yan, Hao

    2016-10-01

    Designer DNA architectures with nanoscale geometric controls provide a programmable molecular toolbox for engineering complex nanodevices. Scaffolded DNA origami has dramatically improved our ability to design and construct DNA nanostructures with finite size and spatial addressability. Here we report a novel design strategy to engineer multilayered wireframe DNA structures by introducing crossover pairs that connect neighboring layers of DNA double helices. These layered crossovers (LX) allow the scaffold or helper strands to travel through different layers and can control the relative orientation of DNA helices in neighboring layers. Using this design strategy, we successfully constructed four versions of two-layer parallelogram structures with well-defined interlayer angles, a three-layer structure with triangular cavities, and a 9- and 15-layer square lattices. This strategy provides a general route to engineer 3D framework DNA nanostructures with controlled cavities and opportunities to design host-guest networks analogs to those produced with metal organic frameworks.

  17. Lattice Boltzmann simulations of 3D crystal growth: Numerical schemes for a phase-field model with anti-trapping current

    CERN Document Server

    Cartalade, Alain; Plapp, Mathis

    2016-01-01

    A lattice-Boltzmann (LB) scheme, based on the Bhatnagar-Gross-Krook (BGK) collision rules is developed for a phase-field model of alloy solidification in order to simulate the growth of dendrites. The solidification of a binary alloy is considered, taking into account diffusive transport of heat and solute, as well as the anisotropy of the solid-liquid interfacial free energy. The anisotropic terms in the phase-field evolution equation, the phenomenological anti-trapping current (introduced in the solute evolution equation to avoid spurious solute trapping), and the variation of the solute diffusion coefficient between phases, make it necessary to modify the equilibrium distribution functions of the LB scheme with respect to the one used in the standard method for the solution of advection-diffusion equations. The effects of grid anisotropy are removed by using the lattices D3Q15 and D3Q19 instead of D3Q7. The method is validated by direct comparison of the simulation results with a numerical code that uses t...

  18. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.

    Science.gov (United States)

    Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin

    2016-07-28

    In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs. PMID:27356177

  19. Anisotropic transport and optical spectroscopy study on antiferromagnetic triangular lattice EuCd2As2 : An interplay between magnetism and charge transport properties

    Science.gov (United States)

    Wang, H. P.; Wu, D. S.; Shi, Y. G.; Wang, N. L.

    2016-07-01

    We present anisotropic transport and optical spectroscopy studies on EuCd2As2 . The measurements reveal that EuCd2As2 is a low carrier density semimetal with moderate anisotropic resistivity ratio. The charge carriers experience very strong scattering from Eu magnetic moments, resulting in a Kondo-like increase of resistivity at low temperature. Below the antiferromagnetic transition temperature at TN=9.5 K, the resistivity drops sharply due to the reduced scattering from the ordered Eu moments. Nevertheless, the anisotropic ratio of ρc/ρa b keeps increasing, suggesting that the antiferromagnetic coupling is along the c axis. The optical spectroscopy measurement further reveals, besides an overdamped reflectance plasma edge at low energy, a strong coupling between phonon and electronic continuum. Our study suggests that EuCd2As2 is a promising candidate displaying intriguing interplay among charge, magnetism, and the underlying crystal lattice.

  20. Study the two dimensional triangular lattice photonic crystal band gap and coupling characters%二维三角形光子晶体带隙与耦合特性研究

    Institute of Scientific and Technical Information of China (English)

    李未; 陈小玲

    2011-01-01

    利用二维三角晶格介质柱光子晶体TE偏振的禁带与介质柱半径的变化关系,分析了二维光子晶体的带隙分布及斜边耦合特性.结果表明,光子禁带的大小受到构成光子晶体的介电材料的空间排列分布以及介质柱半径大小的影响;束缚在光子晶体中的光波可以在波导和谐振腔中进行传输,达到选择输出光波的目的.%The paper study the relation between two dimensional triangular lattice photonic crystal band gap for TE polarizationand dielectric cylinder radius, and study distribution of two dimensional photonic crystal defect state. Results show, the photonic crystal band gaps were distributed by dielectric material space distribution and medium size of the radius; Tied in the photon crystals of light waves can transmission in waveguides and resonator cavity to select the output of light waves.

  1. 几种曲面上的方格和三角格的左右路的计数%Enumeration of Left-right Paths of Square and Triangular Lattices on Some Surfaces

    Institute of Scientific and Technical Information of China (English)

    蒋乐萍; 金贤安

    2011-01-01

    Let G be a finite connected graph cellularly embedded in a closed surface. A left-right path in the embedded graph G is obtained by walking on edges of G, alternately selecting as next edge the leftmost edge and the rightmost edge. In this paper, we determine numbers of left-right paths of square and triangular lattices embedded in torus, Klein bottle and projective plane in a natural way.%设G是连通的胞腔嵌入于某闭曲面的图,G的一条左右路是指沿G的边通过交错的选择最左和最右的边作为下一条边走出的一闭途径.本文计数得到了自然嵌入到环面,Klein瓶和射影平面的方格子和三角格子图的左右路数.

  2. 3D Animation Essentials

    CERN Document Server

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  3. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  4. Development calculational procedures for the neutron physics design of advanced pressurized water reactors (APWR) with tight triangular lattices in hexagonal fuel assemblies

    International Nuclear Information System (INIS)

    The new procedures for the calculation of infinite reactor zones build a synthesis of wellknown fast breeder (FBR) and light water reactor (LWR) methods. The data libraries are based on the 69 energy group structure of the WIMS code for thermal reactors and use the flexible storage mode of the FBR libraries. For the calculation of effective cross sections in the energy of neutron resonances, being very important in the APWR with its strongly epithermal neutron spectrum, several options are available. In most applications improved selfshielding tabulation formalisms (f-factor concept) are used. For more accurate investigations the fine flux programs ULFISP (own development) or RESABK (IKE, Stuttgart) may be selected. All cross section calculations use a modified version of the FBR code GRUCAL. Particularly the calculation of voided lattices may be improved at 69 groups with the program REMOCO or with a new 334 group library. The new calculational procedures could be qualified for a large number of LWR, APWR and FBR applications. The fuel assembly and whole core calculations are performed with available FBR methods. A new reactor core simulation program ARCOSI has been developed for the investigation of an APWR equilibrium core. The required cross sections come from fast interpolations of fuel assembly data on code-own libraries. The whole core calculations are performed with the fast nodal code HEXNODK, adopted from KWU. All calculational procedures are part of the powerful FBR code system KAPROS. (orig.)

  5. Congenital Triangular Alopecia

    OpenAIRE

    Yin Li, Vincent Chum; Yesudian, Paul Devakar

    2015-01-01

    Congenital triangular alopecia (CTA) also known as temporal triangular alopecia is a benign noncicatricial pattern of hair loss. It typically affects the frontotemporal region and rarely involves the temporoparietal or occipital scalp. It is a nonprogressive disorder that presents as a triangular, oval or lancet-shaped patch of alopecia. CTA can manifest at birth or develop later in life. The exact etiology of this condition remains unknown. Rarely, it may be associated with other disorders s...

  6. Simulation of Smooth open Channel Flow by 3D Lattice Boltzmann Method%光滑壁面明渠水流的三维格子玻耳兹曼模拟

    Institute of Scientific and Technical Information of China (English)

    丁磊; 张庆河

    2011-01-01

    明渠水流与泥沙运动、河床演变等问题密切相关,明渠水流特征的研究对于揭示明渠水流作用下的泥沙运动机理具有十分重要的意义.为此.应用新型数值模拟方法三维格子玻耳兹曼方法对明渠均匀流进行了研究.首先介绍了格子玻耳兹曼方法的理论基础、边界条件处理以及流动的驱动方式,接着分别模拟了明渠层流和光滑壁面紊流的近底水流运动.结果表明,得到的明渠层流流速和切应力分布与解析解吻合较好,同时较好地反映了光滑壁面明渠紊流的流速分区结构、紊动特性和阻力规律,从而说明格子玻耳兹曼方法在明渠水流模拟中具有较好的适用性,为进一步采用该方法研究明渠流近底泥沙颗粒运动机理奠定了基础.%Open channel flow has a close relationship with sediment transport and fluvial process. The study of the characteristics of open channel flow plays an important role in revealing the mechanism of sediment transport. A new promising numerical method, 3D lattice Boltzmann method, was applied to the research on uniform open channel flow. The theory of the lattice Boltzmann method, boundary treatment and flow generation were first introduced.Laminar open channel flow and the near-bottom hydrodynamics of smooth turbulent open channel flow were then simulated. Results indicated that the computed velocity and shear stress distribution agreed well with the analytical solution in laminar open channel flow simulation. They also well showed the velocity distribution, turbulence characteristics and friction law of smooth turbulent open channel flow. The lattice Boltzmann method was therefore proved feasible to the open channel flow simulation and provided the basis for the further research of sediment transport mechanism.

  7. EUROPEANA AND 3D

    Directory of Open Access Journals (Sweden)

    D. Pletinckx

    2012-09-01

    Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  8. Solid works 3D

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Cheol Yeong

    2004-02-15

    This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.

  9. Solid works 3D

    International Nuclear Information System (INIS)

    This book explains modeling of solid works 3D and application of 3D CAD/CAM. The contents of this book are outline of modeling such as CAD and 2D and 3D, solid works composition, method of sketch, writing measurement fixing, selecting projection, choosing condition of restriction, practice of sketch, making parts, reforming parts, modeling 3D, revising 3D modeling, using pattern function, modeling necessaries, assembling, floor plan, 3D modeling method, practice floor plans for industrial engineer data aided manufacturing, processing of CAD/CAM interface.

  10. EDGE REMOVAL OF 3D POLYGONAL MODEL USING MAYA API

    Directory of Open Access Journals (Sweden)

    SAMEER ARORA

    2010-09-01

    Full Text Available In various applications of computer graphics, 3D polygonal modeling is used, which consists millions of triangular polygon. In this polygon attributes – vertices, edges and faces’ details are to be stored. In order to control the processing time, storing space, and transfer speed, it is often required to reduce the information ofthese polygonal 3D models. In this paper an effort is made to reduce the number of edges. There are various methods to reduce faces and edges of these 3D models. A C++ dynamic link library as Maya Plugin has been created to remove number of edges of 3D triangular polygon model using the Quadric Error Metrics (QEM in MAYA v2010 x64 API. QEM allows fast and accurate geometric simplification of 3D models.

  11. 3d-3d correspondence revisited

    Science.gov (United States)

    Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-01

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  12. IZDELAVA TISKALNIKA 3D

    OpenAIRE

    Brdnik, Lovro

    2015-01-01

    Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...

  13. INGRID, 3-D Mesh Generator for Program DYNA3D and NIKE3D and FACET and TOPAZ3D

    International Nuclear Information System (INIS)

    1 - Description of program or function: INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D (NESC 9909), NIKE3D (NESC 9725), FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The most important new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition. 2 - Method of solution: Geometries are described primarily using the index space notation of the INGEN program (NESC 975) with an additional type of notation, index progression. Index progressions provide a concise and simple method for describing complex structures; the concept was developed to facilitate defining multiple regions in index space. Rather than specifying the minimum and maximum indices for a region, one specifies the progression of indices along the I, J and K directions, respectively. The index progression method allows the analyst to describe most geometries including nodes and elements with roughly the same amount of input as a solids modeler

  14. 3D and Education

    Science.gov (United States)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  15. Coordination field analysis of rare earth complexes with triangular symmetry

    Institute of Scientific and Technical Information of China (English)

    范英芳; 潘大丰; 杨频

    1997-01-01

    The calculation of the complex matrixes in odd triangular symmetry was accomplished.The configurations of the coordination unit with various triangular symmetries and different ligand numbers were discussed.On the basis of the double-sphere coordination point-charge (DSCPCF) model,the detailed forms of the DSCPCF parameters Bmk and the expressions of the perturbation matrix elements in triangular field (D3,D3h,D3d) were derived.Thereby,the calculation scheme of coordination field perturbation energy of the rare earth complexes with triangular symmetry was constructed After the calculation scheme was programmed,the Stark energies of the crystalline TbAl3(BO3)4 were calculated The results were considerably close to the experimental values

  16. 3D virtuel udstilling

    DEFF Research Database (Denmark)

    Tournay, Bruno; Rüdiger, Bjarne

    2006-01-01

    3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....

  17. COMPARING OF THE 2D-3D GRAVITY CALCULATIONS IN CARTESIAN COORDINATES AND 3D IN CARTESIAN-SPHERICAL COORDINATES

    OpenAIRE

    Çavşak, Hasan; Elmas, Ali

    2014-01-01

    In this study, comparisons of the various calculations are made to achieve the best results in gravity computation. In the three dimensional (3D) gravity study, mass surfaces are defined by dividing the triangle surfaces. The more triangle surface is taken, the more precise definition of mass are made. Triangular pyramids are taken into consideration as the 3D master model. This model is formed between each triangle surface and calculation point. This method can describe complex shaped format...

  18. Blender 3D cookbook

    CERN Document Server

    Valenza, Enrico

    2015-01-01

    This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'

  19. Optimizing triangular mesh generation from range images

    Science.gov (United States)

    Lu, Tianyu; Yun, David Y.

    2000-03-01

    An algorithm for the automatic reconstruction of triangular mesh surface model form range images is presented. The optimal piecewise linear surface approximation problem is defined as: given a set S of points uniformly sampled from a vibrate function f(x,y) on a rectangular grid of dimension W X H, find a minimum triangular mesh approximating the surface with vertices anchored at a subset S' of S, such that the deviation at any sample point is within a given bound of (epsilon) > 0. The algorithm deploys a multi- agent resource planning approach to achieve adaptive, accurate and concise piecewise linear approximation using the L-(infinity) norm. The resulting manifold triangular mesh can be directly used as 3D rendering model for visualization with controllable and guaranteed quality. Due to this dual optimality, the algorithm achieves both storage efficiency and visual quality. The error control scheme further facilitates the construction of models in multiple levels of details, which is desirable in animation and virtual reality moving scenes. Experiments with various benchmark range images form smooth functional surfaces to satellite terrain images yield succinct, accurate and visually pleasant triangular meshes. Furthermore, the independence and multiplicity of agents suggest a natural parallelism for triangulation computation, which provides a promising solution for the real-time exploration of large data sets.

  20. 3D scene modeling from multiple range views

    Science.gov (United States)

    Sequeira, Vitor; Goncalves, Joao G. M.; Ribeiro, M. Isabel

    1995-09-01

    This paper presents a new 3D scene analysis system that automatically reconstructs the 3D geometric model of real-world scenes from multiple range images acquired by a laser range finder on board of a mobile robot. The reconstruction is achieved through an integrated procedure including range data acquisition, geometrical feature extraction, registration, and integration of multiple views. Different descriptions of the final 3D scene model are obtained: a polygonal triangular mesh, a surface description in terms of planar and biquadratics surfaces, and a 3D boundary representation. Relevant experimental results from the complete 3D scene modeling are presented. Direct applications of this technique include 3D reconstruction and/or update of architectual or industrial plans into a CAD model, design verification of buildings, navigation of autonomous robots, and input to virtual reality systems.

  1. Congenital temporal triangular alopecia.

    OpenAIRE

    Bargman, H

    1984-01-01

    Congenital temporal triangular alopecia is a form of nonscarring alopecia that, as its name suggests, is present at birth. Four cases are reported. One patient underwent hair transplantation, which was successful and might be useful in other patients. Cases occurring in a father and his son suggest for the first time a genetic link.

  2. Series of Reciprocal Triangular Numbers

    Science.gov (United States)

    Bruckman, Paul; Dence, Joseph B.; Dence, Thomas P.; Young, Justin

    2013-01-01

    Reciprocal triangular numbers have appeared in series since the very first infinite series were summed. Here we attack a number of subseries of the reciprocal triangular numbers by methodically expressing them as integrals.

  3. Radiochromic 3D Detectors

    Science.gov (United States)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  4. 3D Projection Installations

    DEFF Research Database (Denmark)

    Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle

    2014-01-01

    Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article...... contributes to the understanding of the distinctive characteristics of such a new medium, and identifies three strategies for designing 3-D projection installations: establishing space; interplay between the digital and the physical; and transformation of materiality. The principal empirical case, From...... Fingerplan to Loop City, is a 3-D projection installation presenting the history and future of city planning for the Copenhagen area in Denmark. The installation was presented as part of the 12th Architecture Biennale in Venice in 2010....

  5. Development of a version of the reactor dynamics code DYN3D applicable for High Temperature Reactors; Entwicklung einer Version des Reaktordynamikcodes DYN3D fuer Hochtemperaturreaktoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, Ulrich; Apanasevich, Pavel; Baier, Silvio; Duerigen, Susan; Fridman, Emil; Grahn, Alexander; Kliem, Soeren; Merk, Bruno

    2012-07-15

    Based on the reactor dynamics code DYN3D for the simulation of transient processes in Light Water Reactors, a code version DYN3D-HTR for application to graphitemoderated, gas-cooled block-type high temperature reactors has been developed. This development comprises: - the methodical improvement of the 3D steady-state neutron flux calculation for the hexagonal geometry of the HTR fuel element blocks - the development of methods for the generation of homogenised cross section data taking into account the double heterogeneity of the fuel element block structure - the implementation of a 3D model for heat conduction and heat transport in the graphite matrix. The nodal method for neutron flux calculation based on SP3 transport approximation was extended to hexagonal fuel element geometry, where the hexagons are subdivided into triangles, thus the method had finally to be derived for triangular geometry. In triangular geometry, a subsequent subdivision of the hexagonal elements can be considered, and therefore, the effect of systematic mesh refinement can be studied. The algorithm was verified by comparison with Monte Carlo reference solutions, on the node-wise level, as well as also on the pin-wise level. New procedures were developed for the homogenization of the double-heterogeneous fuel element structures. One the one hand, the so-called Reactivity equivalent Physical Transformation (RPT), the two-step homogenization method based on 2D deterministic lattice calculations, was extended to cells with different temperatures of the materials. On the other hand, the progress in development of Monte Carlo methods for spectral calculations, in particular the development of the code SERPENT, opened a new, fully consistent 3D approach, where all details of the structures on fuel particle, fuel compact and fuel block level can be taken into account within one step. Moreover, a 3D heat conduction and heat transport model was integrated into DYN3D to be able to simulate radial

  6. Herramientas SIG 3D

    Directory of Open Access Journals (Sweden)

    Francisco R. Feito Higueruela

    2010-04-01

    Full Text Available Applications of Geographical Information Systems on several Archeology fields have been increasing during the last years. Recent avances in these technologies make possible to work with more realistic 3D models. In this paper we introduce a new paradigm for this system, the GIS Thetrahedron, in which we define the fundamental elements of GIS, in order to provide a better understanding of their capabilities. At the same time the basic 3D characteristics of some comercial and open source software are described, as well as the application to some samples on archeological researchs

  7. TOWARDS: 3D INTERNET

    OpenAIRE

    Ms. Swapnali R. Ghadge

    2013-01-01

    In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot o...

  8. Bootstrapping 3D fermions

    Science.gov (United States)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  9. Interaktiv 3D design

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2002-01-01

    Projektet undersøger potentialet for interaktiv 3D design via Internettet. Arkitekt Jørn Utzons projekt til Espansiva blev udviklet som et byggesystem med det mål, at kunne skabe mangfoldige planmuligheder og mangfoldige facade- og rumudformninger. Systemets bygningskomponenter er digitaliseret som...... 3D elementer og gjort tilgængelige. Via Internettet er det nu muligt at sammenstille og afprøve en uendelig  række bygningstyper som  systemet blev tænkt og udviklet til....

  10. Tangible 3D Modelling

    DEFF Research Database (Denmark)

    Hejlesen, Aske K.; Ovesen, Nis

    2012-01-01

    This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through facil...

  11. 3D Harmonic Echocardiography:

    NARCIS (Netherlands)

    M.M. Voormolen

    2007-01-01

    textabstractThree dimensional (3D) echocardiography has recently developed from an experimental technique in the ’90 towards an imaging modality for the daily clinical practice. This dissertation describes the considerations, implementation, validation and clinical application of a unique

  12. Synthesized Optimization of Triangular Mesh

    Institute of Scientific and Technical Information of China (English)

    HU Wenqiang; YANG Wenyu

    2006-01-01

    Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.

  13. Congenital Triangular Alopecia.

    Science.gov (United States)

    Yin Li, Vincent Chum; Yesudian, Paul Devakar

    2015-01-01

    Congenital triangular alopecia (CTA) also known as temporal triangular alopecia is a benign noncicatricial pattern of hair loss. It typically affects the frontotemporal region and rarely involves the temporoparietal or occipital scalp. It is a nonprogressive disorder that presents as a triangular, oval or lancet-shaped patch of alopecia. CTA can manifest at birth or develop later in life. The exact etiology of this condition remains unknown. Rarely, it may be associated with other disorders such as Down's syndrome and phakomatosis pigmentovascularis. The diagnosis is based on its distinct clinical appearance. Histologically, hair follicles are miniaturized and replaced by sparse vellus hair follicles. Tricoscopy using a polarized light handheld dermatoscope can be a useful diagnostic tool. CTA is often asymptomatic and remains unchanged throughout the life. No treatment is required. Surgical intervention with follicular unit hair transplantation can provide a satisfactory cosmetic result. In this paper, we have identified 126 cases of CTA in the published literature cited on PubMed between 1905 and 2015. From the available evidence, 79% of patients with CTA presented with unilateral hair loss, 18.5% with bilateral involvement and rarely, with occipital alopecia (2.5%). There was no gender predilection. These figures are entirely consistent with previously published data. Physicians should remember to consider CTA as a potential diagnosis in any patient presenting with a nonscarring alopecia in order to avoid unnecessary investigations and treatments. PMID:26180448

  14. Upper Triangular Matrix of Lie Algebra and a New Discrete Integrable Coupling System

    Institute of Scientific and Technical Information of China (English)

    YU Fa-Jun; ZHANG Hong-Qing

    2007-01-01

    The upper triangular matrix of Lie algebra is used to construct integrable couplings of discrete solition equations.Correspondingly,a feasible way to construct integrable couplings is presented.A nonlinear lattice soliton equation spectral problem is obtained and leads to a novel hierarchy of the nonlinear lattice equation hierarchy.It indicates that the study of integrable couplings using upper triangular matrix of Lie algebra is an important step towards constructing integrable systems.

  15. On the peculiar properties of triangular-chain EuCr{sub 3}(BO{sub 3}){sub 4} antiferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Gondek, Ł., E-mail: lgondek@agh.edu.pl [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Szytuła, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków (Poland); Przewoźnik, J.; Żukrowski, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Prokhorov, A.; Chernush, L.; Zubov, E. [A.A. Galkin Donetsk Physico-Technical Institute, NANU, 83114 Donetsk, R. Luxembourg str. 72 (Ukraine); Dyakonov, V. [A.A. Galkin Donetsk Physico-Technical Institute, NANU, 83114 Donetsk, R. Luxembourg str. 72 (Ukraine); Institute of Physics, PAS, 02-668 Warsaw, Al. Lotników 32/46 (Poland); Duraj, R. [Institute of Physics Technical University of Cracow, Podchorazych 1, 30-084 Krakow (Poland); Tyvanchuk, Yu. [Analytical Chemistry Department, Ivan Franko National University of Lviv, Kyryla and Mephodiya 6, 79005 Lviv (Ukraine)

    2014-02-15

    In this paper we report studies on EuCr{sub 3}(BO{sub 3}){sub 4} compound, that is a member of newly discovered family of huntite-related specimens for non-linear optics. For the first time, the uncommon temperature dependence of the EuCr{sub 3}(BO{sub 3}){sub 4} lattice parameters is reported. Additionally, the magnetism of this compound is extremely interesting. Namely, a possible interplay in between potentially magnetic rare-earth ions and 3d metal stacked within quasi-1D chain that can lead to a great variety of magnetic behaviour. Indeed, in our studies we have found 3D-long range ordering with metamagnetic behaviour, while at higher temperature the magnetic chains become uncoupled. - Graphical abstract: Torsion-like vibrations are the key to understand negative thermal expansion along the a-axis. Display Omitted - Highlights: • EuCr{sub 3}(BO{sub 3}){sub 4} is a peculiar triangular-chain antiferromagnet. • Rare earth sublattice is non-magnetic with Eu{sup 3+} configuration. • Cr{sup 3+} magnetic moments show 1-D behaviour along with spin fluctuations. • Torsion vibrations of Cr triangular tubes lead to anomalous expansion of unit cell.

  16. Massive 3D Supergravity

    CERN Document Server

    Andringa, Roel; de Roo, Mees; Hohm, Olaf; Sezgin, Ergin; Townsend, Paul K

    2009-01-01

    We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered `massive 3D gravity'. Another is a `new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.

  17. Massive 3D supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Andringa, Roel; Bergshoeff, Eric A; De Roo, Mees; Hohm, Olaf [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Sezgin, Ergin [George and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Townsend, Paul K, E-mail: E.A.Bergshoeff@rug.n, E-mail: O.Hohm@rug.n, E-mail: sezgin@tamu.ed, E-mail: P.K.Townsend@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2010-01-21

    We construct the N=1 three-dimensional supergravity theory with cosmological, Einstein-Hilbert, Lorentz Chern-Simons, and general curvature squared terms. We determine the general supersymmetric configuration, and find a family of supersymmetric adS vacua with the supersymmetric Minkowski vacuum as a limiting case. Linearizing about the Minkowski vacuum, we find three classes of unitary theories; one is the supersymmetric extension of the recently discovered 'massive 3D gravity'. Another is a 'new topologically massive supergravity' (with no Einstein-Hilbert term) that propagates a single (2,3/2) helicity supermultiplet.

  18. 3D Digital Modelling

    DEFF Research Database (Denmark)

    Hundebøl, Jesper

    ABSTRACT: Lack of productivity in construction is a well known issue. Despite the fact that causes hereof are multiple, the introduction of information technology is a frequently observed response to almost any challenge. ICT in construction is a thoroughly researched matter, however, the current...... important to appreciate the analysis. Before turning to the presentation of preliminary findings and a discussion of 3D digital modelling, it begins, however, with an outline of industry specific ICT strategic issues. Paper type. Multi-site field study...

  19. TOWARDS: 3D INTERNET

    Directory of Open Access Journals (Sweden)

    Ms. Swapnali R. Ghadge

    2013-08-01

    Full Text Available In today’s ever-shifting media landscape, it can be a complex task to find effective ways to reach your desired audience. As traditional media such as television continue to lose audience share, one venue in particular stands out for its ability to attract highly motivated audiences and for its tremendous growth potential the 3D Internet. The concept of '3D Internet' has recently come into the spotlight in the R&D arena, catching the attention of many people, and leading to a lot of discussions. Basically, one can look into this matter from a few different perspectives: visualization and representation of information, and creation and transportation of information, among others. All of them still constitute research challenges, as no products or services are yet available or foreseen for the near future. Nevertheless, one can try to envisage the directions that can be taken towards achieving this goal. People who take part in virtual worlds stay online longer with a heightened level of interest. To take advantage of that interest, diverse businesses and organizations have claimed an early stake in this fast-growing market. They include technology leaders such as IBM, Microsoft, and Cisco, companies such as BMW, Toyota, Circuit City, Coca Cola, and Calvin Klein, and scores of universities, including Harvard, Stanford and Penn State.

  20. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data......, making them different from typical, existing box shaping techniques. The basis of the proposed techniques is a new algorithm for constructing a full box from just three of its corners. The evaluation of the new techniques compares their precision and completion times in a 9 degree-of-freedom (Do......F) docking experiment against an existing technique, which requires the user to perform the rotation and scaling of the box explicitly. The precision of the users' box construction is evaluated by a novel error metric measuring the difference between two boxes. The results of the experiment strongly indicate...

  1. 3D printing for dummies

    CERN Document Server

    Hausman, Kalani Kirk

    2014-01-01

    Get started printing out 3D objects quickly and inexpensively! 3D printing is no longer just a figment of your imagination. This remarkable technology is coming to the masses with the growing availability of 3D printers. 3D printers create 3-dimensional layered models and they allow users to create prototypes that use multiple materials and colors.  This friendly-but-straightforward guide examines each type of 3D printing technology available today and gives artists, entrepreneurs, engineers, and hobbyists insight into the amazing things 3D printing has to offer. You'll discover methods for

  2. 3D String Theory and Umbral Moonshine

    CERN Document Server

    Kachru, Shamit; Volpato, Roberto

    2016-01-01

    The simplest string theory compactifications to 3D with 16 supercharges -- the heterotic string on $T^7$, and type II strings on $K3 \\times T^3$ -- are related by U-duality, and share a moduli space of vacua parametrized by $O(8,24; \\mathbb{Z}) \\backslash O(8,24) / (O(8) \\times O(24))$. One can think of this as the moduli space of even, self-dual 32-dimensional lattices with signature (8,24). At 24 special points in moduli space, the lattice splits as $\\Gamma^{8,0} \\oplus \\Gamma^{0,24}$. $\\Gamma^{0,24}$ can be the Leech lattice or any of 23 Niemeier lattices, while $\\Gamma^{8,0}$ is the $E_8$ root lattice. We show that starting from this observation, one can find a precise connection between the Umbral groups and type IIA string theory on $K3$. This provides a natural physical starting point for understanding Mathieu and Umbral moonshine. The maximal unbroken subgroups of Umbral groups in 6D (or any other limit) are those obtained by starting at the associated Niemeier point and moving in moduli space while p...

  3. Martian terrain - 3D

    Science.gov (United States)

    1997-01-01

    This area of terrain near the Sagan Memorial Station was taken on Sol 3 by the Imager for Mars Pathfinder (IMP). 3D glasses are necessary to identify surface detail.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  4. 3D monitor

    OpenAIRE

    Szkandera, Jan

    2009-01-01

    Tato bakalářská práce se zabývá návrhem a realizací systému, který umožní obraz scény zobrazovaný na ploše vnímat prostorově. Prostorové vnímání 2D obrazové informace je umožněno jednak stereopromítáním a jednak tím, že se obraz mění v závislosti na poloze pozorovatele. Tato práce se zabývá hlavně druhým z těchto problémů. This Bachelor's thesis goal is to design and realize system, which allows user to perceive 2D visual information as three-dimensional. 3D visual preception of 2D image i...

  5. 3D game environments create professional 3D game worlds

    CERN Document Server

    Ahearn, Luke

    2008-01-01

    The ultimate resource to help you create triple-A quality art for a variety of game worlds; 3D Game Environments offers detailed tutorials on creating 3D models, applying 2D art to 3D models, and clear concise advice on issues of efficiency and optimization for a 3D game engine. Using Photoshop and 3ds Max as his primary tools, Luke Ahearn explains how to create realistic textures from photo source and uses a variety of techniques to portray dynamic and believable game worlds.From a modern city to a steamy jungle, learn about the planning and technological considerations for 3D modelin

  6. X3D: Extensible 3D Graphics Standard

    OpenAIRE

    Daly, Leonard; Brutzman, Don

    2007-01-01

    The article of record as published may be located at http://dx.doi.org/10.1109/MSP.2007.905889 Extensible 3D (X3D) is the open standard for Web-delivered three-dimensional (3D) graphics. It specifies a declarative geometry definition language, a run-time engine, and an application program interface (API) that provide an interactive, animated, real-time environment for 3D graphics. The X3D specification documents are freely available, the standard can be used without paying any royalties,...

  7. 3D Printing an Octohedron

    OpenAIRE

    Aboufadel, Edward F.

    2014-01-01

    The purpose of this short paper is to describe a project to manufacture a regular octohedron on a 3D printer. We assume that the reader is familiar with the basics of 3D printing. In the project, we use fundamental ideas to calculate the vertices and faces of an octohedron. Then, we utilize the OPENSCAD program to create a virtual 3D model and an STereoLithography (.stl) file that can be used by a 3D printer.

  8. Salient Local 3D Features for 3D Shape Retrieval

    CERN Document Server

    Godil, Afzal

    2011-01-01

    In this paper we describe a new formulation for the 3D salient local features based on the voxel grid inspired by the Scale Invariant Feature Transform (SIFT). We use it to identify the salient keypoints (invariant points) on a 3D voxelized model and calculate invariant 3D local feature descriptors at these keypoints. We then use the bag of words approach on the 3D local features to represent the 3D models for shape retrieval. The advantages of the method are that it can be applied to rigid as well as to articulated and deformable 3D models. Finally, this approach is applied for 3D Shape Retrieval on the McGill articulated shape benchmark and then the retrieval results are presented and compared to other methods.

  9. Influence of shear viscosity on the correlation between the triangular flow and initial spatial triangularity

    International Nuclear Information System (INIS)

    In a hydrodynamic model, with fluctuating initial conditions, the correlation between triangular flow and initial spatial triangularity is studied. The triangular flow, even in ideal fluid, is not strongly correlated with the initial triangularity. The correlation is largely reduced in viscous fluid. Elliptic flow on the other hand appears to be strongly correlated with initial eccentricity. Weak correlation between triangular flow and initial triangularity indicates that a part of triangular flow is unrelated to initial triangularity. Triangularity acquired during the fluid evolution also contributes to the triangular flow.

  10. 3D modelling and recognition

    OpenAIRE

    Rodrigues, Marcos; Robinson, Alan; Alboul, Lyuba; Brink, Willie

    2006-01-01

    3D face recognition is an open field. In this paper we present a method for 3D facial recognition based on Principal Components Analysis. The method uses a relatively large number of facial measurements and ratios and yields reliable recognition. We also highlight our approach to sensor development for fast 3D model acquisition and automatic facial feature extraction.

  11. TOPAZ-3D, 3-D Steady-State or Transient Heat Transfer by Finite Element Method

    International Nuclear Information System (INIS)

    1 - Description of program or function: TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either, isotropic or orthotropic. A variety of time- and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances. 2 - Method of solution: TOPAZ3D solves the differential equation of heat conduction in a three-dimensional solid by the finite element method. TOPAZ3D uses an eight-node trilinear hexahedral element for spatial discretization of the geometry. The hexahedral element can degenerate to a six-node triangular prism and a four-node tetrahedron. These elements are integrated with a 2x2x2 Gauss quadrature rule, with temperature dependence of the properties accounted for at the Gauss point. Time integration is performed using a generalized trapezoidal method. Fixed point iteration with relaxation is used to satisfy equilibrium in nonlinear problems. 3 - Restrictions on the complexity of the problem: The phase change, slide surface, internal element, and bulk node features are not implemented

  12. Progress in sorting individual atoms in 3D

    Science.gov (United States)

    Wu, Tsung-Yao; Kumar, Aishwarya; Wang, Yang; Weiss, David

    2016-05-01

    An exactly unity filled optical lattice is a desirable initial state for a neutral atom quantum computer. We have previously proposed an efficient way to compact a partially filled lattice into a perfectly filled one, by combining site-resolved imaging, site-selective qubit rotations and state-selective motion steps. We have previously demonstrated site-resolved imaging and site-selective rotations in our system of cesium atoms in a 40% filled 5x5x5 3D lattice. We have now demonstrated the final element, state-selective motion steps in 3D produced by rotating the polarizations of one of the lattice beams in each pair. We will present our progress in putting all the elements together to reach perfect unity filling. Supported by NSF.

  13. 3D-skannaukseen perehtyminen

    OpenAIRE

    Santaluoto, Olli

    2012-01-01

    Tässä insinöörityössä tarkastellaan erilaisia 3D-skannaustekniikoita ja menetelmiä. Työssä myös kerrotaan esimerkkien avulla eri 3D-skannaustekniikoiden käyttökohteista. 3D-skannaus on Suomessa vielä melko harvinaista, siksi eri tekniikat ja käyttömahdollisuudet ovat monille tuntemattomia. 3D-skanneri on laite, jolla tutkitaan reaalimaailman esineitä tai ympäristöä keräämällä dataa kohteen muodoista. 3D-skannerit ovat hyvin paljon vastaavia tavallisen kameran kanssa. Kuten kameroilla, 3D...

  14. 3D Printing Functional Nanocomposites

    OpenAIRE

    Leong, Yew Juan

    2016-01-01

    3D printing presents the ability of rapid prototyping and rapid manufacturing. Techniques such as stereolithography (SLA) and fused deposition molding (FDM) have been developed and utilized since the inception of 3D printing. In such techniques, polymers represent the most commonly used material for 3D printing due to material properties such as thermo plasticity as well as its ability to be polymerized from monomers. Polymer nanocomposites are polymers with nanomaterials composited into the ...

  15. 3D Elevation Program—Virtual USA in 3D

    Science.gov (United States)

    Lukas, Vicki; Stoker, J.M.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  16. 3D IBFV : Hardware-Accelerated 3D Flow Visualization

    NARCIS (Netherlands)

    Telea, Alexandru; Wijk, Jarke J. van

    2003-01-01

    We present a hardware-accelerated method for visualizing 3D flow fields. The method is based on insertion, advection, and decay of dye. To this aim, we extend the texture-based IBFV technique for 2D flow visualization in two main directions. First, we decompose the 3D flow visualization problem in a

  17. Interactive 3D multimedia content

    CERN Document Server

    Cellary, Wojciech

    2012-01-01

    The book describes recent research results in the areas of modelling, creation, management and presentation of interactive 3D multimedia content. The book describes the current state of the art in the field and identifies the most important research and design issues. Consecutive chapters address these issues. These are: database modelling of 3D content, security in 3D environments, describing interactivity of content, searching content, visualization of search results, modelling mixed reality content, and efficient creation of interactive 3D content. Each chapter is illustrated with example a

  18. 3D Bayesian contextual classifiers

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    2000-01-01

    We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours.......We extend a series of multivariate Bayesian 2-D contextual classifiers to 3-D by specifying a simultaneous Gaussian distribution for the feature vectors as well as a prior distribution of the class variables of a pixel and its 6 nearest 3-D neighbours....

  19. 3-D printers for libraries

    CERN Document Server

    Griffey, Jason

    2014-01-01

    As the maker movement continues to grow and 3-D printers become more affordable, an expanding group of hobbyists is keen to explore this new technology. In the time-honored tradition of introducing new technologies, many libraries are considering purchasing a 3-D printer. Jason Griffey, an early enthusiast of 3-D printing, has researched the marketplace and seen several systems first hand at the Consumer Electronics Show. In this report he introduces readers to the 3-D printing marketplace, covering such topics asHow fused deposition modeling (FDM) printing workBasic terminology such as build

  20. 3D for Graphic Designers

    CERN Document Server

    Connell, Ellery

    2011-01-01

    Helping graphic designers expand their 2D skills into the 3D space The trend in graphic design is towards 3D, with the demand for motion graphics, animation, photorealism, and interactivity rapidly increasing. And with the meteoric rise of iPads, smartphones, and other interactive devices, the design landscape is changing faster than ever.2D digital artists who need a quick and efficient way to join this brave new world will want 3D for Graphic Designers. Readers get hands-on basic training in working in the 3D space, including product design, industrial design and visualization, modeling, ani

  1. Using 3D in Visualization

    DEFF Research Database (Denmark)

    Wood, Jo; Kirschenbauer, Sabine; Döllner, Jürgen;

    2005-01-01

    to display 3D imagery. The extra cartographic degree of freedom offered by using 3D is explored and offered as a motivation for employing 3D in visualization. The use of VR and the construction of virtual environments exploit navigational and behavioral realism, but become most usefil when combined...... with abstracted representations embedded in a 3D space. The interactions between development of geovisualization, the technology used to implement it and the theory surrounding cartographic representation are explored. The dominance of computing technologies, driven particularly by the gaming industry...

  2. Simulation of Magnetic Cluster Growth on 2-D Triangular Lattice Based on Power Law Interaction%三角点阵基底上基于幂次相互作用的二维磁性团簇磁结构研究

    Institute of Scientific and Technical Information of China (English)

    吴一琦; 许晓军

    2012-01-01

    The initial growth stage of the 2-dimmsion magnetic cluster on the triangular surface-lattice was modeled and simulated in Monte Carlo method,on the basis of the diffusion limited aggression (DLA) model.The original work is the addition of a spin freedom (up or down) to each particle involved in a power-law coupling interaction. In the simulation, the kinetic aggregation of the magnetic particles on 2-dimension lattice with different exponents,a,and different coupling parameters, J, were evaluated. In addition, the spin distributions and magnetizations of the magnetic fractal clusters, as well as their evolution with the parameters were calculated. Possible improvement of the simulation was tentatively discussed in a thought-provoking way.%在扩散限制凝聚模型基础上引入粒子的自旋自由度(包括自旋向上和向下),将自旋耦合系数扩展为随粒子间距离幂次变化的非常数项J/ra,采用Monte Carlo方法研究了在二维三角点阵基底上不同幂指数α以及耦合强度系数J值磁性粒子的分形生长规律,给出了此类磁性分形团簇的自旋分布、磁化强度等随模型参数的演化规律.

  3. Using game engine for 3D terrain visualisation of GIS data: A review

    International Nuclear Information System (INIS)

    This paper reviews on the 3D terrain visualisation of GIS data using game engines that are available in the market as well as open source. 3D terrain visualisation is a technique used to visualise terrain information from GIS data such as a digital elevation model (DEM), triangular irregular network (TIN) and contour. Much research has been conducted to transform the 2D view of map to 3D. There are several terrain visualisation softwares that are available for free, which include Cesium, Hftool and Landserf. This review paper will help interested users to better understand the current state of art in 3D terrain visualisation of GIS data using game engines

  4. Using game engine for 3D terrain visualisation of GIS data: A review

    Science.gov (United States)

    Che Mat, Ruzinoor; Shariff, Abdul Rashid Mohammed; Nasir Zulkifli, Abdul; Shafry Mohd Rahim, Mohd; Hafiz Mahayudin, Mohd

    2014-06-01

    This paper reviews on the 3D terrain visualisation of GIS data using game engines that are available in the market as well as open source. 3D terrain visualisation is a technique used to visualise terrain information from GIS data such as a digital elevation model (DEM), triangular irregular network (TIN) and contour. Much research has been conducted to transform the 2D view of map to 3D. There are several terrain visualisation softwares that are available for free, which include Cesium, Hftool and Landserf. This review paper will help interested users to better understand the current state of art in 3D terrain visualisation of GIS data using game engines.

  5. High-field magnetization and ESR in the triangular-lattice antiferromagnets Ba{sub 3}MnSb{sub 2}O{sub 9} and Ba{sub 3}TNb{sub 2}O{sub 9} (T=Ni, Co)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Ouyang, Z.W., E-mail: zwouyang@mail.hust.edu.cn [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ruan, M.Y.; Guo, Y.M.; Cheng, J.J. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Tian, Z.M. [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Xia, Z.C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Rao, G.H. [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004 (China)

    2015-11-01

    We report high-field magnetization and electronic spin resonance (ESR) study on the triangular-lattice antiferromagnets Ba{sub 3}MnSb{sub 2}O{sub 9} and Ba{sub 3}TNb{sub 2}O{sub 9} (T=Ni, Co). The antiferromagnetic (AFM) ordering at T{sub N} is clearly characterized by the temperature dependent ESR spectra. In Ba{sub 3}CoNb{sub 2}O{sub 9}, the complicated ESR peaks are observed above T{sub N}. No obvious frequency–field relationship could be deduced. In Ba{sub 3}NiNb{sub 2}O{sub 9}, the AFM resonance with easy-plane anisotropy is observed, and accordingly, the magnetic exchange interactions are estimated. For Ba{sub 3}MnSb{sub 2}O{sub 9}, the remarkable finding is that single resonance peak at paramagnetic state splits into double peaks below the ordering temperature. Possible interpretations for these unusual AFM resonance modes have been proposed. - Highlights: • In Ba{sub 3}NiNb{sub 2}O{sub 9}, anisotropy is observed, exchange interactions are estimated. • In Ba{sub 3}MnSb{sub 2}O{sub 9}, single resonance peaksplits into double peaks below T{sub N}. • Complicated ESR spectra have been observed in Ba{sub 3}CoNb{sub 2}O{sub 9} above T{sub N}.

  6. Improvement of 3D Scanner

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The disadvantage remaining in 3D scanning system and its reasons are discussed. A new host-and-slave structure with high speed image acquisition and processing system is proposed to quicken the image processing and improve the performance of 3D scanning system.

  7. 3D Printing for Bricks

    OpenAIRE

    ECT Team, Purdue

    2015-01-01

    Building Bytes, by Brian Peters, is a project that uses desktop 3D printers to print bricks for architecture. Instead of using an expensive custom-made printer, it uses a normal standard 3D printer which is available for everyone and makes it more accessible and also easier for fabrication.

  8. Validation of multipoint kinetics model against 3D Trikin Code

    International Nuclear Information System (INIS)

    Validation of multipoint kinetics formulation for RELAP5 code has been carried out against 3D TRIKIN code. Core behavior of an asymmetric reactivity transient has been simulated through artificial tuning of lattice constants in 3D code. Individual node normalized reactivity has been conserved and power estimates from multipoint model have been compared with 3D simulation. It has been observed that localized peak power estimates from multipoint simulation are on higher side and therefore are conservative in nature. Improvements in multipoint formulation in regards to evolving coupling coefficients and involving more number of nodes can help in improving its accuracy to some extent. (author)

  9. Error Analysis Of 3d Polygonal Model:A Survey

    Directory of Open Access Journals (Sweden)

    Devendra Singh Rajput

    2012-05-01

    Full Text Available Various applications of computer graphics, (like animation, scientific visualization, and virtual reality involve the manipulation of geometric models. They are generally represented by triangular meshes due to its wide acceptance to process on rendering systems. The need of realism and high visual fidelity and the latest advances on scanning devices has increased complexity and size of triangular meshes. The original 3D model gets modified because of activities like approximation, transmission, processing and storage etc. Mostly the modification occurs due to simplification approaches which primarily use geometric distance metric as their simplification criteria. But it is hard to measure a small distance error accurately whereas other geometric or appearance error (like high curvature, thin region, color, texture, normals and volumetric has greater importance. Hence it is essential to understand the applicability of various parameters to evaluate the quality of 3D model. This paper briefly surveys the various errors analysis techniques, error metrics and tools to assess the quality of 3D mesh models.

  10. 3D printing in dentistry.

    Science.gov (United States)

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435

  11. 3D printing in dentistry.

    Science.gov (United States)

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  12. PLOT3D user's manual

    Science.gov (United States)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  13. Influence of asperities on fluid and thermal flow in a fracture: a coupled Lattice Boltzmann study

    CERN Document Server

    Neuville, Amélie; Toussaint, Renaud

    2013-01-01

    The characteristics of the hydro-thermal flow which occurs when a cold fluid is injected into a hot fractured bedrock depend on the morphology of the fracture. We consider a sharp triangular asperity, invariant in one direction, perturbing an otherwise flat fracture. We investigate its influence on the macroscopic hydraulic transmissivity and heat transfer efficiency, at fixed low Reynolds number. In this study, numerical simulations are done with a coupled lattice Boltzmann method that solves both the complete Navier-Stokes and advection-diffusion equations in three dimensions. The results are compared with those obtained under lubrication approximations which rely on many hypotheses and neglect the three-dimensional (3D) effects. The lubrication results are obtained by analytically solving the Stokes equation and a two-dimensional (integrated over the thickness) advection-diffusion equation. We use a lattice Boltzmann method with a double distribution (for mass and energy transport) on hypercubic and cubic ...

  14. 3-D Video Processing for 3-D TV

    Science.gov (United States)

    Sohn, Kwanghoon; Kim, Hansung; Kim, Yongtae

    One of the most desirable ways of realizing high quality information and telecommunication services has been called "The Sensation of Reality," which can be achieved by visual communication based on 3-D (Three-dimensional) images. These kinds of 3-D imaging systems have revealed potential applications in the fields of education, entertainment, medical surgery, video conferencing, etc. Especially, three-dimensional television (3-D TV) is believed to be the next generation of TV technology. Figure 13.1 shows how TV's display technologies have evolved , and Fig. 13.2 details the evolution of TV broadcasting as forecasted by the ETRI (Electronics and Telecommunications Research Institute). It is clear that 3-D TV broadcasting will be the next development in this field, and realistic broadcasting will soon follow.

  15. Reconstruction of 3-D digital cores using a hybrid method

    Institute of Scientific and Technical Information of China (English)

    Liu Xuefeng; Sun Jianmeng; Wang Haitao

    2009-01-01

    A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing (SA) method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method (FEM) and lattice Boltzmann method (LBM), respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.

  16. ADT-3D Tumor Detection Assistant in 3D

    Directory of Open Access Journals (Sweden)

    Jaime Lazcano Bello

    2008-12-01

    Full Text Available The present document describes ADT-3D (Three-Dimensional Tumor Detector Assistant, a prototype application developed to assist doctors diagnose, detect and locate tumors in the brain by using CT scan. The reader may find on this document an introduction to tumor detection; ADT-3D main goals; development details; description of the product; motivation for its development; result’s study; and areas of applicability.

  17. Unassisted 3D camera calibration

    Science.gov (United States)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  18. Facial-paralysis diagnostic system based on 3D reconstruction

    Science.gov (United States)

    Khairunnisaa, Aida; Basah, Shafriza Nisha; Yazid, Haniza; Basri, Hassrizal Hassan; Yaacob, Sazali; Chin, Lim Chee

    2015-05-01

    The diagnostic process of facial paralysis requires qualitative assessment for the classification and treatment planning. This result is inconsistent assessment that potential affect treatment planning. We developed a facial-paralysis diagnostic system based on 3D reconstruction of RGB and depth data using a standard structured-light camera - Kinect 360 - and implementation of Active Appearance Models (AAM). We also proposed a quantitative assessment for facial paralysis based on triangular model. In this paper, we report on the design and development process, including preliminary experimental results. Our preliminary experimental results demonstrate the feasibility of our quantitative assessment system to diagnose facial paralysis.

  19. 3D animation of facial plastic surgery based on computer graphics

    Science.gov (United States)

    Zhang, Zonghua; Zhao, Yan

    2013-12-01

    More and more people, especial women, are getting desired to be more beautiful than ever. To some extent, it becomes true because the plastic surgery of face was capable in the early 20th and even earlier as doctors just dealing with war injures of face. However, the effect of post-operation is not always satisfying since no animation could be seen by the patients beforehand. In this paper, by combining plastic surgery of face and computer graphics, a novel method of simulated appearance of post-operation will be given to demonstrate the modified face from different viewpoints. The 3D human face data are obtained by using 3D fringe pattern imaging systems and CT imaging systems and then converted into STL (STereo Lithography) file format. STL file is made up of small 3D triangular primitives. The triangular mesh can be reconstructed by using hash function. Top triangular meshes in depth out of numbers of triangles must be picked up by ray-casting technique. Mesh deformation is based on the front triangular mesh in the process of simulation, which deforms interest area instead of control points. Experiments on face model show that the proposed 3D animation facial plastic surgery can effectively demonstrate the simulated appearance of post-operation.

  20. Handbook of 3D integration

    CERN Document Server

    Garrou , Philip; Ramm , Peter

    2014-01-01

    Edited by key figures in 3D integration and written by top authors from high-tech companies and renowned research institutions, this book covers the intricate details of 3D process technology.As such, the main focus is on silicon via formation, bonding and debonding, thinning, via reveal and backside processing, both from a technological and a materials science perspective. The last part of the book is concerned with assessing and enhancing the reliability of the 3D integrated devices, which is a prerequisite for the large-scale implementation of this emerging technology. Invaluable reading fo

  1. Tuotekehitysprojekti: 3D-tulostin

    OpenAIRE

    Pihlajamäki, Janne

    2011-01-01

    Opinnäytetyössä tutustuttiin 3D-tulostamisen teknologiaan. Työssä käytiin läpi 3D-tulostimesta tehty tuotekehitysprojekti. Sen lisäksi esiteltiin yleisellä tasolla tuotekehitysprosessi ja syntyneiden tulosten mahdollisia suojausmenetelmiä. Tavoitteena tässä työssä oli kehittää markkinoilta jo löytyvää kotitulostin-tasoista 3D-laiteteknologiaa lähemmäksi ammattilaistason ratkaisua. Tavoitteeseen pyrittiin keskittymällä parantamaan laitteella saavutettavaa tulostustarkkuutta ja -nopeutt...

  2. 3D on the internet

    OpenAIRE

    Puntar, Matej

    2012-01-01

    The purpose of this thesis is the presentation of already established and new technologies of displaying 3D content in a web browser. The thesis begins with a short presentation of the history of 3D content available on the internet and its development together with advantages and disadvantages of individual technologies. The latter two are described in detail as well is their use and the differences among them. Special emphasis has been given to WebGL, the newest technology of 3D conte...

  3. Color 3D Reverse Engineering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object's images in the measurement process: Firs...

  4. Exploration of 3D Printing

    OpenAIRE

    Lin, Zeyu

    2014-01-01

    3D printing technology is introduced and defined in this Thesis. Some methods of 3D printing are illustrated and their principles are explained with pictures. Most of the essential parts are presented with pictures and their effects are explained within the whole system. Problems on Up! Plus 3D printer are solved and a DIY product is made with this machine. The processes of making product are recorded and the items which need to be noticed during the process are the highlight in this th...

  5. Materialedreven 3d digital formgivning

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2010-01-01

    traditionel keramisk produktionssammenhæng. Problemstillingen opmuntrede endvidere til i et samarbejde med en programmør at udvikle et 3d digitalt redskab, der er blevet kaldt et digitalt interaktivt formgivningsredskab (DIF). Eksperimentet undersøger interaktive 3d digitale dynamiske systemer, der...... samarbejder med designere fra fagområder som interaktionsdesign og programmering. Afhandlingen peger på et fremtidigt forskningsfelt indenfor generative og responderende digitale systemer til 3d formgivning, der ligeledes inkluderer følesansen. Endvidere er det relevant at forske i, hvordan de RP teknikker...... formgivning og Rapid Prototyping (RP). RP er en fællesbetegnelse for en række af de teknikker, der muliggør at overføre den digitale form til 3d fysisk form. Forskningsprojektet koncentrerer sig om to overordnede forskningsspørgsmål. Det første handler om, hvordan viden og erfaring indenfor det keramiske...

  6. 3D Face Apperance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Astrom, K

    2006-01-01

    We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations......We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations...

  7. Main: TATCCAYMOTIFOSRAMY3D [PLACE

    Lifescience Database Archive (English)

    Full Text Available TATCCAYMOTIFOSRAMY3D S000256 01-August-2006 (last modified) kehi TATCCAY motif foun...d in rice (O.s.) RAmy3D alpha-amylase gene promoter; Y=T/C; a GATA motif as its antisense sequence; TATCCAY ...motif and G motif (see S000130) are responsible for sugar repression (Toyofuku et al. 1998); GATA; amylase; sugar; repression; rice (Oryza sativa) TATCCAY ...

  8. AI 3D Cybug Gaming

    CERN Document Server

    Ahmed, Zeeshan

    2010-01-01

    In this short paper I briefly discuss 3D war Game based on artificial intelligence concepts called AI WAR. Going in to the details, I present the importance of CAICL language and how this language is used in AI WAR. Moreover I also present a designed and implemented 3D War Cybug for AI WAR using CAICL and discus the implemented strategy to defeat its enemies during the game life.

  9. 3D Face Appearance Model

    DEFF Research Database (Denmark)

    Lading, Brian; Larsen, Rasmus; Åström, Kalle

    2006-01-01

    We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}......We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}...

  10. Magnetic properties of a spin-1 triangular Ising system

    International Nuclear Information System (INIS)

    We studied some magnetic behaviors of the Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of the spin-1 BC model in a triangular lattice, such as magnetization, susceptibility, phase diagram and hysteresis behaviors, are investigated in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as the tetracritical and critical end special points are found to depend on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, single and double hysteresis loops are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility makes a peak at these points. - Highlights: • The triangular Ising system is investigated within EFT with correlations. • The effects of the interaction parameters on spin-1 BC model are studied. • The phase diagrams are found for the different interaction parameters. • The hysteresis behaviors of the system are examined. • The system shows the tricritical, tetracritical and critical end special points

  11. Magnetic properties of a spin-1 triangular Ising system

    Energy Technology Data Exchange (ETDEWEB)

    Ertaş, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Kocakaplan, Yusuf [Graduate School of Natural and Applied Sciences, Erciyes University, 38039 Kayseri (Turkey); Kantar, Ersin, E-mail: ersinkantar@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2015-07-15

    We studied some magnetic behaviors of the Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of the spin-1 BC model in a triangular lattice, such as magnetization, susceptibility, phase diagram and hysteresis behaviors, are investigated in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as the tetracritical and critical end special points are found to depend on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, single and double hysteresis loops are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility makes a peak at these points. - Highlights: • The triangular Ising system is investigated within EFT with correlations. • The effects of the interaction parameters on spin-1 BC model are studied. • The phase diagrams are found for the different interaction parameters. • The hysteresis behaviors of the system are examined. • The system shows the tricritical, tetracritical and critical end special points.

  12. Subjectivity, objectivity, and triangular space.

    Science.gov (United States)

    Britton, Ronald

    2004-01-01

    The author reviews his ideas on subjectivity, objectivity, and the third position in the psychoanalytic encounter, particularly in clinical work with borderline and narcissistic patients. Using the theories of Melanie Klein and Wilfred Bion as a basis, the author describes his concept of triangular space. A case presentation of a particular type of narcissistic patient illustrates the principles discussed.

  13. Ultrasound fields from triangular apertures

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1996-01-01

    The pulsed field from a triangular aperture mounted in an infinite, rigidbaffle is calculated. The approach of spatial impulse responses,as developed by Tupholme and Stepanishen, is used. By this both the emitted and received pulsed ultrasound field can be found for any transducerexcitation...

  14. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    Science.gov (United States)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  15. MPML3D: Scripting Agents for the 3D Internet.

    Science.gov (United States)

    Prendinger, Helmut; Ullrich, Sebastian; Nakasone, Arturo; Ishizuka, Mitsuru

    2011-05-01

    The aim of this paper is two-fold. First, it describes a scripting language for specifying communicative behavior and interaction of computer-controlled agents ("bots") in the popular three-dimensional (3D) multiuser online world of "Second Life" and the emerging "OpenSimulator" project. While tools for designing avatars and in-world objects in Second Life exist, technology for nonprogrammer content creators of scenarios involving scripted agents is currently missing. Therefore, we have implemented new client software that controls bots based on the Multimodal Presentation Markup Language 3D (MPML3D), a highly expressive XML-based scripting language for controlling the verbal and nonverbal behavior of interacting animated agents. Second, the paper compares Second Life and OpenSimulator platforms and discusses the merits and limitations of each from the perspective of agent control. Here, we also conducted a small study that compares the network performance of both platforms.

  16. From 3D view to 3D print

    Science.gov (United States)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  17. The dual gonihedric 3D Ising model

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, D A [Department of Mathematics, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS (United Kingdom); Ranasinghe, R P K C M, E-mail: D.A.Johnston@hw.ac.uk [Department of Mathematics, University of Sri Jayewardenepura, Gangodawila (Sri Lanka)

    2011-07-22

    We investigate the dual of the {kappa} = 0 gonihedric Ising model on a 3D cubic lattice, which may be written as an anisotropically coupled Ashkin-Teller model. The original {kappa} = 0 gonihedric model has a purely plaquette interaction, displays a first order transition and possesses a highly degenerate ground state. We find that the dual model admits a similar large ground state degeneracy as a result of the anisotropic couplings and investigate the coupled mean-field equations for the model on a single cube. We also carry out Monte Carlo simulations which confirm a first order phase transition in the model and suggest that the ground state degeneracy persists throughout the low temperature phase. Some exploratory cooling simulations also hint at non-trivial dynamical behaviour.

  18. The dual gonihedric 3D Ising model

    International Nuclear Information System (INIS)

    We investigate the dual of the κ = 0 gonihedric Ising model on a 3D cubic lattice, which may be written as an anisotropically coupled Ashkin-Teller model. The original κ = 0 gonihedric model has a purely plaquette interaction, displays a first order transition and possesses a highly degenerate ground state. We find that the dual model admits a similar large ground state degeneracy as a result of the anisotropic couplings and investigate the coupled mean-field equations for the model on a single cube. We also carry out Monte Carlo simulations which confirm a first order phase transition in the model and suggest that the ground state degeneracy persists throughout the low temperature phase. Some exploratory cooling simulations also hint at non-trivial dynamical behaviour.

  19. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    Science.gov (United States)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  20. Finite layer and triangular prism element method to subsidence prediction and stress analysis in underground mining

    Institute of Scientific and Technical Information of China (English)

    LIU Li-min(刘立民); LIU Han-long(刘汉龙); LIAN Chuan-jie(连传杰)

    2003-01-01

    The application of the finite layer & triangular prism element method to the 3D ground subsidence and stress analysis caused by mining is presented. The layer elements and the triangular prism elements have been alternatively used in the numerical simulation system, the displacement pattern, strain matrix, elastic matrix, stiffness matrix, load matrix and the stress matrix of the layer element and triangular prism element have been presented. By means of the Fortran90 programming language, a numerical simulation system based on finite layer & triangular prism element have been built up, and this system is suitable for subsidence prediction and stress analysis of all mining condition and mining methods. Comparing with the infinite element method, this approach dramatically reduces the size of the set of equations that need to be solved, and greatly reduces the amount of data preparation required. It not only saves the internal storage, and the computation time, but also decreases the cost.

  1. Remote 3D Medical Consultation

    Science.gov (United States)

    Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.

    Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.

  2. Novel 3D media technologies

    CERN Document Server

    Dagiuklas, Tasos

    2015-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The contributions are based on the results of the FP7 European Project ROMEO, which focuses on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the future Internet. The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of consistent video quality to fixed and mobile users. ROMEO will present hybrid networking solutions that combine the DVB-T2 and DVB-NGH broadcas...

  3. 3D future internet media

    CERN Document Server

    Dagiuklas, Tasos

    2014-01-01

    This book describes recent innovations in 3D media and technologies, with coverage of 3D media capturing, processing, encoding, and adaptation, networking aspects for 3D Media, and quality of user experience (QoE). The main contributions are based on the results of the FP7 European Projects ROMEO, which focus on new methods for the compression and delivery of 3D multi-view video and spatial audio, as well as the optimization of networking and compression jointly across the Future Internet (www.ict-romeo.eu). The delivery of 3D media to individual users remains a highly challenging problem due to the large amount of data involved, diverse network characteristics and user terminal requirements, as well as the user’s context such as their preferences and location. As the number of visual views increases, current systems will struggle to meet the demanding requirements in terms of delivery of constant video quality to both fixed and mobile users. ROMEO will design and develop hybrid-networking solutions that co...

  4. 3D Imager and Method for 3D imaging

    NARCIS (Netherlands)

    Kumar, P.; Staszewski, R.; Charbon, E.

    2013-01-01

    3D imager comprising at least one pixel, each pixel comprising a photodetectorfor detecting photon incidence and a time-to-digital converter system configured for referencing said photon incidence to a reference clock, and further comprising a reference clock generator provided for generating the re

  5. Modification of 3D milling machine to 3D printer

    OpenAIRE

    Halamíček, Lukáš

    2015-01-01

    Tato práce se zabývá přestavbou gravírovací frézky na 3D tiskárnu. V první části se práce zabývá možnými technologiemi 3D tisku a možností jejich využití u přestavby. Dále jsou popsány a vybrány vhodné součásti pro přestavbu. V další části je realizováno řízení ohřevu podložky, trysky a řízení posuvu drátu pomocí softwaru TwinCat od společnosti Beckhoff na průmyslovém počítači. Výsledkem práce by měla být oživená 3D tiskárna. This thesis deals with rebuilding of engraving machine to 3D pri...

  6. Markerless 3D Face Tracking

    DEFF Research Database (Denmark)

    Walder, Christian; Breidt, Martin; Bulthoff, Heinrich;

    2009-01-01

    We present a novel algorithm for the markerless tracking of deforming surfaces such as faces. We acquire a sequence of 3D scans along with color images at 40Hz. The data is then represented by implicit surface and color functions, using a novel partition-of-unity type method of efficiently...... combining local regressors using nearest neighbor searches. Both these functions act on the 4D space of 3D plus time, and use temporal information to handle the noise in individual scans. After interactive registration of a template mesh to the first frame, it is then automatically deformed to track...... the scanned surface, using the variation of both shape and color as features in a dynamic energy minimization problem. Our prototype system yields high-quality animated 3D models in correspondence, at a rate of approximately twenty seconds per timestep. Tracking results for faces and other objects...

  7. Crowded Field 3D Spectroscopy

    CERN Document Server

    Becker, T; Roth, M M; Becker, Thomas; Fabrika, Sergei; Roth, Martin M.

    2003-01-01

    The quantitative spectroscopy of stellar objects in complex environments is mainly limited by the ability of separating the object from the background. Standard slit spectroscopy, restricting the field of view to one dimension, is obviously not the proper technique in general. The emerging Integral Field (3D) technique with spatially resolved spectra of a two-dimensional field of view provides a great potential for applying advanced subtraction methods. In this paper an image reconstruction algorithm to separate point sources and a smooth background is applied to 3D data. Several performance tests demonstrate the photometric quality of the method. The algorithm is applied to real 3D observations of a sample Planetary Nebula in M31, whose spectrum is contaminated by the bright and complex galaxy background. The ability of separating sources is also studied in a crowded stellar field in M33.

  8. 3D-grafiikkamoottori mobiililaitteille

    OpenAIRE

    Vahlman, Lauri

    2014-01-01

    Tässä insinöörityössä käydään läpi mobiililaitteille suunnatun yksinkertaisen 3D-grafiikkamoottorin suunnittelu ja toteutus käyttäen OpenGL ES -rajapintaa. Työssä esitellään grafiikkamoottorin toteutuksessa käytettyjä tekniikoita sekä tutustutaan moottorin rakenteeseen ja toteutuksellisiin yksityiskohtiin. Työn alkupuolella tutustutaan myös modernin 3D-grafiikan yleisiin periaatteisiin ja toimintaan sekä käydään läpi 3D-grafiikkaan liittyviä suorituskykyongelmia. Työn loppupuolella esitel...

  9. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...

  10. Microfluidic 3D Helix Mixers

    Directory of Open Access Journals (Sweden)

    Georgette B. Salieb-Beugelaar

    2016-10-01

    Full Text Available Polymeric microfluidic systems are well suited for miniaturized devices with complex functionality, and rapid prototyping methods for 3D microfluidic structures are increasingly used. Mixing at the microscale and performing chemical reactions at the microscale are important applications of such systems and we therefore explored feasibility, mixing characteristics and the ability to control a chemical reaction in helical 3D channels produced by the emerging thread template method. Mixing at the microscale is challenging because channel size reduction for improving solute diffusion comes at the price of a reduced Reynolds number that induces a strictly laminar flow regime and abolishes turbulence that would be desired for improved mixing. Microfluidic 3D helix mixers were rapidly prototyped in polydimethylsiloxane (PDMS using low-surface energy polymeric threads, twisted to form 2-channel and 3-channel helices. Structure and flow characteristics were assessed experimentally by microscopy, hydraulic measurements and chromogenic reaction, and were modeled by computational fluid dynamics. We found that helical 3D microfluidic systems produced by thread templating allow rapid prototyping, can be used for mixing and for controlled chemical reaction with two or three reaction partners at the microscale. Compared to the conventional T-shaped microfluidic system used as a control device, enhanced mixing and faster chemical reaction was found to occur due to the combination of diffusive mixing in small channels and flow folding due to the 3D helix shape. Thus, microfluidic 3D helix mixers can be rapidly prototyped using the thread template method and are an attractive and competitive method for fluid mixing and chemical reactions at the microscale.

  11. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  12. Advanced 3-D Ultrasound Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Morten Fischer

    The main purpose of the PhD project was to develop methods that increase the 3-D ultrasound imaging quality available for the medical personnel in the clinic. Acquiring a 3-D volume gives the medical doctor the freedom to investigate the measured anatomy in any slice desirable after the scan has...... beamforming. This is achieved partly because synthetic aperture imaging removes the limitation of a fixed transmit focal depth and instead enables dynamic transmit focusing. Lately, the major ultrasound companies have produced ultrasound scanners using 2-D transducer arrays with enough transducer elements...

  13. A numerically accurate and robust expression for bistatic scattering from a plane triangular facet

    DEFF Research Database (Denmark)

    Wendelboe, Gorm; Jacobsen, Finn; Bell, Judith

    2006-01-01

    This work is related to modeling of synthetic sonar images of naval mines or other objects. Considered here is the computation of high frequency scattering from the surface of a rigid 3D-object numerically represented by plane triangular facets. The far field scattered pressure from each facet...

  14. Fabrication of Nanostructured Poly-ε-caprolactone 3D Scaffolds for 3D Cell Culture Technology

    KAUST Repository

    Schipani, Rossana

    2015-04-21

    Tissue engineering is receiving tremendous attention due to the necessity to overcome the limitations related to injured or diseased tissues or organs. It is the perfect combination of cells and biomimetic-engineered materials. With the appropriate biochemical factors, it is possible to develop new effective bio-devices that are capable to improve or replace biological functions. Latest developments in microfabrication methods, employing mostly synthetic biomaterials, allow the production of three-dimensional (3D) scaffolds that are able to direct cell-to-cell interactions and specific cellular functions in order to drive tissue regeneration or cell transplantation. The presented work offers a rapid and efficient method of 3D scaffolds fabrication by using optical lithography and micro-molding techniques. Bioresorbable polymer poly-ε-caprolactone (PCL) was the material used thanks to its high biocompatibility and ability to naturally degrade in tissues. 3D PCL substrates show a particular combination in the designed length scale: cylindrical shaped pillars with 10μm diameter, 10μm height, arranged in a hexagonal lattice with spacing of 20μm were obtained. The sidewalls of the pillars were nanostructured by attributing a 3D architecture to the scaffold. The suitability of these devices as cell culture technology supports was evaluated by plating NIH/3T3 mouse embryonic fibroblasts and human Neural Stem Cells (hNSC) on them. Scanning Electron Microscopy (SEM) analysis was carried out in order to examine the micro- and nano-patterns on the surface of the supports. In addition, after seeding of cells, SEM and immunofluorescence characterization of the fabricated systems were performed to check adhesion, growth and proliferation. It was observed that cells grow and develop healthy on the bio-polymeric devices by giving rise to well-interconnected networks. 3D PCL nano-patterned pillared scaffold therefore may have considerable potential as effective tool for

  15. PubChem3D: Biologically relevant 3-D similarity

    Directory of Open Access Journals (Sweden)

    Kim Sunghwan

    2011-07-01

    Full Text Available Abstract Background The use of 3-D similarity techniques in the analysis of biological data and virtual screening is pervasive, but what is a biologically meaningful 3-D similarity value? Can one find statistically significant separation between "active/active" and "active/inactive" spaces? These questions are explored using 734,486 biologically tested chemical structures, 1,389 biological assay data sets, and six different 3-D similarity types utilized by PubChem analysis tools. Results The similarity value distributions of 269.7 billion unique conformer pairs from 734,486 biologically tested compounds (all-against-all from PubChem were utilized to help work towards an answer to the question: what is a biologically meaningful 3-D similarity score? The average and standard deviation for the six similarity measures STST-opt, CTST-opt, ComboTST-opt, STCT-opt, CTCT-opt, and ComboTCT-opt were 0.54 ± 0.10, 0.07 ± 0.05, 0.62 ± 0.13, 0.41 ± 0.11, 0.18 ± 0.06, and 0.59 ± 0.14, respectively. Considering that this random distribution of biologically tested compounds was constructed using a single theoretical conformer per compound (the "default" conformer provided by PubChem, further study may be necessary using multiple diverse conformers per compound; however, given the breadth of the compound set, the single conformer per compound results may still apply to the case of multi-conformer per compound 3-D similarity value distributions. As such, this work is a critical step, covering a very wide corpus of chemical structures and biological assays, creating a statistical framework to build upon. The second part of this study explored the question of whether it was possible to realize a statistically meaningful 3-D similarity value separation between reputed biological assay "inactives" and "actives". Using the terminology of noninactive-noninactive (NN pairs and the noninactive-inactive (NI pairs to represent comparison of the "active/active" and

  16. 3D Face Apperance Model

    OpenAIRE

    Lading, Brian; Larsen, Rasmus; Astrom, K

    2006-01-01

    We build a 3D face shape model, including inter- and intra-shape variations, derive the analytical Jacobian of its resulting 2D rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations

  17. 3D Face Appearance Model

    OpenAIRE

    Lading, Brian; Larsen, Rasmus; Åström, Kalle

    2006-01-01

    We build a 3d face shape model, including inter- and intra-shape variations, derive the analytical jacobian of its resulting 2d rendered image, and show example of its fitting performance with light, pose, id, expression and texture variations.}

  18. Making Inexpensive 3-D Models

    Science.gov (United States)

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  19. When Art Meets 3D

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The presentation of the vanguard work,My Dream3D,the innovative production by the China Disabled People’s Performing Art Troupe(CDPPAT),directed by Joy Joosang Park,provided the film’s domestic premiere at Beijing’s Olympic Park onApril7.The show provided an intriguing insight not

  20. 3D terahertz beam profiling

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Strikwerda, Andrew; Wang, Tianwu;

    2013-01-01

    We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...

  1. 3D Printing: Exploring Capabilities

    Science.gov (United States)

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  2. Viewing galaxies in 3D

    CERN Document Server

    Krajnović, Davor

    2016-01-01

    Thanks to a technique that reveals galaxies in 3D, astronomers can now show that many galaxies have been wrongly classified. Davor Krajnovi\\'c argues that the classification scheme proposed 85 years ago by Edwin Hubble now needs to be revised.

  3. Householder triangularization of a quasimatrix

    OpenAIRE

    Trefethen, Lloyd N.

    2008-01-01

    A standard algorithm for computing the QR factorization of a matrix A is Householder triangularization. Here this idea is generalized to the situation in which A is a quasimatrix, that is, a “matrix” whose “columns” are functions defined on an interval [a,b]. Applications are mentioned to quasimatrix leastsquares fitting, singular value decomposition, and determination of ranks, norms, and condition numbers, and numerical illustrations are presented using the chebfun system.

  4. Air-guiding photonic bandgap fiber with improved triangular air-silica photonic crystal cladding

    OpenAIRE

    Yan, M; Shum, P

    2005-01-01

    We introduce a small-core air-guiding photonic crystal fiber whose cladding is made of improved air-silica photonic crystal with non-circular air holes placed in triangular lattice. The fiber achieves un-disturbed bandgap guidance over 350nm wavelength range.

  5. Neutron-scattering cross section of the S=1/2 Heisenberg triangular antiferromagnet

    DEFF Research Database (Denmark)

    Lefmann, K.; Hedegård, P.

    1994-01-01

    In this paper we use a Schwinger-boson mean-field approach to calculate the neutron-scattering cross section from the S = 1/2 antiferromagnet with nearest-neighbor isotropic Heisenberg interaction on a two-dimensional triangular lattice. We investigate two solutions for T = 0: (i) a state with long...

  6. Triangular Fibrocartilage Complex MR Imaging

    Directory of Open Access Journals (Sweden)

    Seyed Hassan Mostafavi

    2010-05-01

    Full Text Available Interpretation of MR imaging of the wrist may be difficult because of the small size of this joint, its complex anatomy, and its sometimes poorly unders-tood pathologic lesions. A recent study revealed that MR imaging of the wrist influences clinicians' diagnoses and management plans in most patients. "nWhich structures make up the triangular fibrocarti-lage complex (TFCC are not universally agreed upon. In most descriptions, however, the TFCC is composed of the triangular fibrocartilage (TFC, the meniscus homolog, the ulnar collateral ligament, the dorsal and volar radioulnar ligaments and the sheath of the extensor carpi ulnaris tendon. The ulnolunate and ulnotriquetral ligaments may also be considered as part of the TFCC. These structures are a complex unit that function as a stabilizing element in the pivot movement of the radius and ulna and limit the lateral deviation of the carpus. The distal radioulnar joint is primarily stabilized by the TFCC. The TFC functions as a cushion between the ulnar head and carpal bones. Many of the structures that make up the complex are connected by fibrous bands. "nThis presentation summarizes the current diagnostic criteria that can be useful in interpreting abnormalities of the triangular fibrocartilage complex (TFCC of the wrist in this difficult topic in joint MR imaging

  7. Priprava 3D modelov za 3D tisk

    OpenAIRE

    Pikovnik, Tomaž

    2015-01-01

    Po mnenju nekaterih strokovnjakov bo aditivna proizvodnja (ali 3D tiskanje) spremenila proizvodnjo industrijo, saj si bo vsak posameznik lahko natisnil svoj objekt po želji. V diplomski nalogi so predstavljene nekatere tehnologije aditivne proizvodnje. V nadaljevanju diplomske naloge je predstavljena izdelava makete hiše v merilu 1:100, vse od modeliranja do tiskanja. Poseben poudarek je posvečen predelavi modela, da je primeren za tiskanje, kjer je razvit pristop za hitrejše i...

  8. Post processing of 3D models for 3D printing

    OpenAIRE

    Pikovnik, Tomaž

    2015-01-01

    According to the opinion of some experts the additive manufacturing or 3D printing will change manufacturing industry, because any individual could print their own model according to his or her wishes. In this graduation thesis some of the additive manufacturing technologies are presented. Furthermore in the production of house scale model in 1:100 is presented, starting from modeling to printing. Special attention is given to postprocessing of the building model elements us...

  9. 3D Cameras: 3D Computer Vision of Wide Scope

    OpenAIRE

    May, Stefan; Pervoelz, Kai; Surmann, Hartmut

    2007-01-01

    First of all, a short comparison of range sensors and their underlying principles was given. The chapter further focused on 3D cameras. The latest innovations have given a significant improvement for the measurement accuracy, wherefore this technology has attracted attention in the robotics community. This was also the motivation for the examination in this chapter. On this account, several applications were presented, which represents common problems in the domain of autonomous robotics. For...

  10. DYNA3D2000*, Explicit 3-D Hydrodynamic FEM Program

    International Nuclear Information System (INIS)

    1 - Description of program or function: DYNA3D2000 is a nonlinear explicit finite element code for analyzing 3-D structures and solid continuum. The code is vectorized and available on several computer platforms. The element library includes continuum, shell, beam, truss and spring/damper elements to allow maximum flexibility in modeling physical problems. Many materials are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding, single surface contact and automatic contact generation. 2 - Method of solution: Discretization of a continuous model transforms partial differential equations into algebraic equations. A numerical solution is then obtained by solving these algebraic equations through a direct time marching scheme. 3 - Restrictions on the complexity of the problem: Recent software improvements have eliminated most of the user identified limitations with dynamic memory allocation and a very large format description that has pushed potential problem sizes beyond the reach of most users. The dominant restrictions remain in code execution speed and robustness, which the developers constantly strive to improve

  11. Combined registration of 3D tibia and femur implant models in 3D magnetic resonance images

    Science.gov (United States)

    Englmeier, Karl-Hans; Siebert, Markus; von Eisenhart-Rothe, Ruediger; Graichen, Heiko

    2008-03-01

    The most frequent reasons for revision of total knee arthroplasty are loosening and abnormal axial alignment leading to an unphysiological kinematic of the knee implant. To get an idea about the postoperative kinematic of the implant, it is essential to determine the position and orientation of the tibial and femoral prosthesis. Therefore we developed a registration method for fitting 3D CAD-models of knee joint prostheses into an 3D MR image. This rigid registration is the basis for a quantitative analysis of the kinematics of knee implants. Firstly the surface data of the prostheses models are converted into a voxel representation; a recursive algorithm determines all boundary voxels of the original triangular surface data. Secondly an initial preconfiguration of the implants by the user is still necessary for the following step: The user has to perform a rough preconfiguration of both remaining prostheses models, so that the fine matching process gets a reasonable starting point. After that an automated gradient-based fine matching process determines the best absolute position and orientation: This iterative process changes all 6 parameters (3 rotational- and 3 translational parameters) of a model by a minimal amount until a maximum value of the matching function is reached. To examine the spread of the final solutions of the registration, the interobserver variability was measured in a group of testers. This variability, calculated by the relative standard deviation, improved from about 50% (pure manual registration) to 0.5% (rough manual preconfiguration and subsequent fine registration with the automatic fine matching process).

  12. 3D Printable Graphene Composite.

    Science.gov (United States)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-08

    In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  13. 3-D Relativistic MHD Simulations

    Science.gov (United States)

    Nishikawa, K.-I.; Frank, J.; Koide, S.; Sakai, J.-I.; Christodoulou, D. M.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W = 4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure.

  14. 3D Printed Robotic Hand

    Science.gov (United States)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  15. Forensic 3D Scene Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  16. [Real time 3D echocardiography

    Science.gov (United States)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  17. Super lattice formation of an array of volatile wetting droplets

    OpenAIRE

    Burghaus, R.

    1999-01-01

    For an ordered array of critical volatile wetting droplets the formation of a super lattice by an Ostwald-ripening like competition process is considered. The underlying diffusion problem is treated within a quasistatic approximation and to first order in the inverse droplets distance. The approach is rather general but a square lattice and a triangular lattice are studied explicitly. Dispersion relations for the super-lattice growth of these arrays are calculated.

  18. Tomographic particle image velocimetry over a triangular prism in unidirectional flows

    Science.gov (United States)

    Sou, In Mei; Calantoni, Joseph

    2011-11-01

    Using tomographic particle image velocimetry (Tomo-PIV), the full three-dimensional-three-component (3D-3C) flow structure and turbulence characteristics over a triangular prism in a recirculating water tunnel were investigated. Here we present preliminary results from a new Tomo-PIV system for subcritical Froude number flows. Large-scale vortex shedding from the tip of the triangular prism is observed. Results of coherent structure organization analyzed by 3D vorticity calculation will be presented. Using the full 3D-3C instantaneous velocity field, turbulent kinetic energy is directly evaluated without any of the assumptions often needed for 2D PIV measurements. Details of the experimental setup including a unique device designed to perform our Tomo-PIV volume calibration will be discussed. We perform an in-depth turbulent kinetic energy budget and explore the feasibility of extending the measurement technique to other complex flows.

  19. UWB Directive Triangular Patch Antenna

    Directory of Open Access Journals (Sweden)

    A. C. Lepage

    2008-01-01

    Full Text Available Compact directive UWB antennas are presented in this paper. We propose an optimization of the F-probe fed triangular patch antenna. The new design achieves an impedance bandwidth of 69% (3–6.15 GHz and presents good radiation characteristics over the whole impedance bandwidth. The average gain is 6.1 dB. A time-domain study has been performed to characterize the antenna behavior in case a UWB pulse is used. Finally, we propose an alternative solution to facilitate the manufacturing process using metallized foam technology. It also improves the robustness of the antenna as well as reducing its cost.

  20. Wireless 3D Chocolate Printer

    Directory of Open Access Journals (Sweden)

    FROILAN G. DESTREZA

    2014-02-01

    Full Text Available This study is for the BSHRM Students of Batangas State University (BatStateU ARASOF for the researchers believe that the Wireless 3D Chocolate Printer would be helpful in their degree program especially on making creative, artistic, personalized and decorative chocolate designs. The researchers used the Prototyping model as procedural method for the successful development and implementation of the hardware and software. This method has five phases which are the following: quick plan, quick design, prototype construction, delivery and feedback and communication. This study was evaluated by the BSHRM Students and the assessment of the respondents regarding the software and hardware application are all excellent in terms of Accuracy, Effecitveness, Efficiency, Maintainability, Reliability and User-friendliness. Also, the overall level of acceptability of the design project as evaluated by the respondents is excellent. With regard to the observation about the best raw material to use in 3D printing, the chocolate is good to use as the printed material is slightly distorted,durable and very easy to prepare; the icing is also good to use as the printed material is not distorted and is very durable but consumes time to prepare; the flour is not good as the printed material is distorted, not durable but it is easy to prepare. The computation of the economic viability level of 3d printer with reference to ROI is 37.14%. The recommendation of the researchers in the design project are as follows: adding a cooling system so that the raw material will be more durable, development of a more simplified version and improving the extrusion process wherein the user do not need to stop the printing process just to replace the empty syringe with a new one.

  1. Tehokas 3D-animaatiotuotanto

    OpenAIRE

    Järvinen, Manu

    2009-01-01

    Opinnäytetyössä tutkittiin tehokasta tapaa toteuttaa minuutin mittainen animaatio Scene.org Awards -tapahtuman avajaisseremoniaan. Kyseinen video toteutettiin osana opinnäytetyötä. Työhön osallistui tekijän lisäksi 3D-mallintaja sekä muusikko. Työkaluina käytettiin pääasiassa Autodesk 3ds Max-, sekä Adobe After Effects- ja Adobe Photoshop -ohjelmia. Opinnäytetyö koostuu animaatioprojektin tuotantoputken ja tiedostonhallintamallin perinpohjaisesta läpikäymisestä sekä sen asian tutkimisesta...

  2. Virtual 3-D Facial Reconstruction

    Directory of Open Access Journals (Sweden)

    Martin Paul Evison

    2000-06-01

    Full Text Available Facial reconstructions in archaeology allow empathy with people who lived in the past and enjoy considerable popularity with the public. It is a common misconception that facial reconstruction will produce an exact likeness; a resemblance is the best that can be hoped for. Research at Sheffield University is aimed at the development of a computer system for facial reconstruction that will be accurate, rapid, repeatable, accessible and flexible. This research is described and prototypical 3-D facial reconstructions are presented. Interpolation models simulating obesity, ageing and ethnic affiliation are also described. Some strengths and weaknesses in the models, and their potential for application in archaeology are discussed.

  3. Making Inexpensive 3-D Models

    Science.gov (United States)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  4. How 3-D Movies Work

    Institute of Scientific and Technical Information of China (English)

    吕铁雄

    2011-01-01

    难度:★★★★☆词数:450 建议阅读时间:8分钟 Most people see out of two eyes. This is a basic fact of humanity,but it’s what makes possible the illusion of depth(纵深幻觉) that 3-D movies create. Human eyes are spaced about two inches apart, meaning that each eye gives the brain a slightly different perspective(透视感)on the same object. The brain then uses this variance to quickly determine an object’s distance.

  5. An automated 3D reconstruction method of UAV images

    Science.gov (United States)

    Liu, Jun; Wang, He; Liu, Xiaoyang; Li, Feng; Sun, Guangtong; Song, Ping

    2015-10-01

    In this paper a novel fully automated 3D reconstruction approach based on low-altitude unmanned aerial vehicle system (UAVs) images will be presented, which does not require previous camera calibration or any other external prior knowledge. Dense 3D point clouds are generated by integrating orderly feature extraction, image matching, structure from motion (SfM) and multi-view stereo (MVS) algorithms, overcoming many of the cost, time limitations of rigorous photogrammetry techniques. An image topology analysis strategy is introduced to speed up large scene reconstruction by taking advantage of the flight-control data acquired by UAV. Image topology map can significantly reduce the running time of feature matching by limiting the combination of images. A high-resolution digital surface model of the study area is produced base on UAV point clouds by constructing the triangular irregular network. Experimental results show that the proposed approach is robust and feasible for automatic 3D reconstruction of low-altitude UAV images, and has great potential for the acquisition of spatial information at large scales mapping, especially suitable for rapid response and precise modelling in disaster emergency.

  6. Positional Awareness Map 3D (PAM3D)

    Science.gov (United States)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  7. 3D Printable Graphene Composite

    Science.gov (United States)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  8. 3D printed bionic ears.

    Science.gov (United States)

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  9. 3D printed bionic ears.

    Science.gov (United States)

    Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

    2013-06-12

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

  10. LOTT RANCH 3D PROJECT

    International Nuclear Information System (INIS)

    The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data

  11. Magnetic phase diagram of the coupled triangular spin tubes for CsCrF4

    Science.gov (United States)

    Seki, Kouichi; Okunishi, Kouichi

    2015-06-01

    Using Monte Carlo simulations, we explore the magnetic phase diagram of triangular spin tubes coupled with a ferromagnetic intertube interaction for CsCrF4. The planar structure of the coupled tubes is topologically equivalent to the kagome-triangular lattice, which induces nontrivial frustration effects in the system. We particularly find that, depending on the intertube coupling, various ordered phases are actually realized, such as incommensurate order, ferromagnetic order, and cuboc order, which is characterized by the noncoplanar spin structure of the 12 sublattices accompanying the spin chirality breaking. We also discuss the relevance of the results to recent experiments on CsCrF4.

  12. 3D Printing of Graphene Aerogels.

    Science.gov (United States)

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (aerogel presents superelastic and high electrical conduction. PMID:26861680

  13. 3D biometrics systems and applications

    CERN Document Server

    Zhang, David

    2013-01-01

    Includes discussions on popular 3D imaging technologies, combines them with biometric applications, and then presents real 3D biometric systems Introduces many efficient 3D feature extraction, matching, and fusion algorithms Techniques presented have been supported by experimental results using various 3D biometric classifications

  14. Hydrothermal synthesis of 3D porous architectures

    Institute of Scientific and Technical Information of China (English)

    XIAO Wanyan; GU Xiaojun; XUE Dongfeng

    2009-01-01

    A novel porous lanthanide-organic coordination polymer, [Nd(H2O)(HnicO)(TP)]·2H2O (1) (H2nicO=2-hydroxynieotinic acid, TP= terephthalate), was prepared under hydrothermai condition and characterized by single-crystal X-ray diffraction, thermogravimetrie analysis and infrared spectroscopy. Compound 1 exhibited a flexible coordination geometry of lanthanide ions, which possessed a three-dimensional (3D) open framework with one-dimensional (1D) channels containing lattice water molecules. This framework structure exhibited a high stability up to 330 ℃ after removing free water molecules. A homometallic supramolecular framework (Zn(HnicO)2(H2O)2 (2)) was obtained due to the competitive reaction between organic ligands, Nd3+ and Zn2+ ions. The results showed that on the basis of the soft-hard/acid-base principle the coordination selection between metal ions and organic ligands played an essential role in the smart construc-tion of lanthanide architectures.

  15. 3D Printing of Graphene Aerogels.

    Science.gov (United States)

    Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong

    2016-04-01

    3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.

  16. Photopolymers in 3D printing applications

    OpenAIRE

    Pandey, Ramji

    2014-01-01

    3D printing is an emerging technology with applications in several areas. The flexibility of the 3D printing system to use variety of materials and create any object makes it an attractive technology. Photopolymers are one of the materials used in 3D printing with potential to make products with better properties. Due to numerous applications of photopolymers and 3D printing technologies, this thesis is written to provide information about the various 3D printing technologies with particul...

  17. Natural fibre composites for 3D Printing

    OpenAIRE

    Pandey, Kapil

    2015-01-01

    3D printing has been common option for prototyping. Not all the materials are suitable for 3D printing. Various studies have been done and still many are ongoing regarding the suitability of the materials for 3D printing. This thesis work discloses the possibility of 3D printing of certain polymer composite materials. The main objective of this thesis work was to study the possibility for 3D printing the polymer composite material composed of natural fibre composite and various different ...

  18. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi;

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...... with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described...

  19. 3D Energy Harvester Evaluation

    Directory of Open Access Journals (Sweden)

    V. Janicek

    2013-04-01

    Full Text Available This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure (about 100Hz by usage of modified long cantilever spring design, minimum area of the chip, 3D work mode, the ability to be tuned to reach desired parameters, proves promising directions of possible further development.

  20. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  1. Manipulation and control of a bichromatic lattice

    Science.gov (United States)

    Thomas, Claire; Barter, Thomas; Daiss, Severin; Leung, Zephy; Stamper-Kurn, Dan

    2015-05-01

    Recent experiments with ultracold atoms in optical lattices have had great success emulating the simple models of condensed matter systems. These experiments are typically performed with a single site per unit cell. We realize a lattice with up to four sites per unit cell by overlaying an attractive triangular lattice with a repulsive one at twice the wavelength. The relative displacement of the two lattices determines the particular structure. One available configuration is the kagome lattice, which has a flat energy band. In the flat band all kinetic energy states are degenerate, so we have the opportunity to explore a regime where interactions dominate. This bichromatic lattice requires careful stabilization, but offers an opportunity to manipulate the unit cell and band structure by perturbing the lattices relative to one another. I will discuss recent progress.

  2. Spectral properties of random triangular matrices

    CERN Document Server

    Basu, Riddhipratim; Ganguly, Shirshendu; Hazra, Rajat Subhra

    2011-01-01

    We provide a relatively elementary proof of the existence of the limiting spectral distribution (LSD) of symmetric triangular patterned matrices and also show their joint convergence. We also derive the expressions for the moments of the LSD of the symmetric triangular Wigner matrix using properties of Catalan words.

  3. Supernova Remnant in 3-D

    Science.gov (United States)

    2009-01-01

    of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through. The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave. This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron. High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and

  4. Measuring Lattice Strain in Three Dimensions through Electron Microscopy

    NARCIS (Netherlands)

    Goris, B.; Beenhouwer, J. de; Backer, A. de; Zanaga, D.; Batenburg, K.J.; Sánchez-Iglesias, A.; Liz-Marzán, L.M.; Aert, S. van; Sijbers, J.; Bals, S.; Tendeloo, G. van

    2015-01-01

    The three-dimensional (3D) atomic structure of nanomaterials, including strain, is crucial to understand their properties. Here, we investigate lattice strain in Au nanodecahedra using electron tomography. Although different electron tomography techniques enabled 3D characterizations of nanostructur

  5. Improved surface-enhanced Raman scattering on arrays of gold quasi-3D nanoholes

    KAUST Repository

    Yue, Weisheng

    2012-10-04

    Arrays of gold quasi-3D nanoholes were proposed and fabricated as substrates for surface-enhanced Raman scattering (SERS). By detecting rhodamine 6G (R6G) molecules, the gold quasi-3D nanoholes demonstrated an SERS intensity that was 25-62 times higher than that of two-dimensional nanoholes with the same geometrical shapes and periodicities. The larger SERS enhancement of the quasi-3D nanoholes is attributed to the enhanced electromagnetic field on the top-layer nanohole, the bottom nanodiscs and the field coupling between the two layers. In addition, the investigation of the shape dependence of the SERS on the quasi-3D nanoholes demonstrated that the quadratic, circular, triangular and rhombic holes exhibited different SERS properties. Numerical simulations of the electromagnetic properties on the nanostructures were performed with CST Microwave Studio, and the results agree with the experimental observations. © 2012 IOP Publishing Ltd.

  6. Recovery and Visualization of 3D Structure of Chromosomes from Tomographic Reconstruction Images

    Directory of Open Access Journals (Sweden)

    Tsap Leonid V

    2006-01-01

    Full Text Available The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is very important for biologists as it affects chromosome functions, behavior of the cell, and its state. Analysis of chromosome structure is significant in the detection of diseases, identification of chromosomal abnormalities, study of DNA structural conformation, in-depth study of chromosomal surface morphology, observation of in vivo behavior of the chromosomes over time, and in monitoring environmental gene mutations. The methodology incorporates thresholding based on a histogram analysis with a polyline splitting algorithm, contour extraction via active contours, and detection of the 3D chromosome structure by establishing corresponding regions throughout the slices. Visualization using point cloud meshing generates a 3D surface. The 3D triangular mesh of the chromosomes provides surface detail and allows a user to interactively analyze chromosomes using visualization software.

  7. Constructing parametric triangular patches with boundary conditions

    Institute of Scientific and Technical Information of China (English)

    Hui Liu; Jun Ma; Fuhua Cheng

    2008-01-01

    The problem of constructing a parametric triangular patch to smoothly connect three surface patches is studied. Usually, these surface patches are defined on different parameter spaces. Therefore, it is necessary to define interpolation conditions, with values from the given surface patches, on the boundary of the triangular patch that can ensure smooth transition between different parameter spaces. In this paper we present a new method to define boundary conditions. Boundary conditions defined by the new method have the same parameter space if the three given surface patches can be converted into the same form through affine transformation. Consequently, any of the classic methods for constructing functional triangular patches can be used directly to construct a parametric triangular patch to connect given surface patches with G continuity. The resulting parametric triangular patch preserves precision of the applied classic method.

  8. Highly-stretchable 3D-architected Mechanical Metamaterials

    Science.gov (United States)

    Jiang, Yanhui; Wang, Qiming

    2016-09-01

    Soft materials featuring both 3D free-form architectures and high stretchability are highly desirable for a number of engineering applications ranging from cushion modulators, soft robots to stretchable electronics; however, both the manufacturing and fundamental mechanics are largely elusive. Here, we overcome the manufacturing difficulties and report a class of mechanical metamaterials that not only features 3D free-form lattice architectures but also poses ultrahigh reversible stretchability (strain > 414%), 4 times higher than that of the existing counterparts with the similar complexity of 3D architectures. The microarchitected metamaterials, made of highly stretchable elastomers, are realized through an additive manufacturing technique, projection microstereolithography, and its postprocessing. With the fabricated metamaterials, we reveal their exotic mechanical behaviors: Under large-strain tension, their moduli follow a linear scaling relationship with their densities regardless of architecture types, in sharp contrast to the architecture-dependent modulus power-law of the existing engineering materials; under large-strain compression, they present tunable negative-stiffness that enables ultrahigh energy absorption efficiencies. To harness their extraordinary stretchability and microstructures, we demonstrate that the metamaterials open a number of application avenues in lightweight and flexible structure connectors, ultraefficient dampers, 3D meshed rehabilitation structures and stretchable electronics with designed 3D anisotropic conductivity.

  9. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  10. ORMGEN3D, 3-D Crack Geometry FEM Mesh Generator

    International Nuclear Information System (INIS)

    1 - Description of program or function: ORMGEN3D is a finite element mesh generator for computational fracture mechanics analysis. The program automatically generates a three-dimensional finite element model for six different crack geometries. These geometries include flat plates with straight or curved surface cracks and cylinders with part-through cracks on the outer or inner surface. Mathematical or user-defined crack shapes may be considered. The curved cracks may be semicircular, semi-elliptical, or user-defined. A cladding option is available that allows for either an embedded or penetrating crack in the clad material. 2 - Method of solution: In general, one eighth or one-quarter of the structure is modelled depending on the configuration or option selected. The program generates a core of special wedge or collapsed prism elements at the crack front to introduce the appropriate stress singularity at the crack tip. The remainder of the structure is modelled with conventional 20-node iso-parametric brick elements. Element group I of the finite element model consists of an inner core of special crack tip elements surrounding the crack front enclosed by a single layer of conventional brick elements. Eight element divisions are used in a plane orthogonal to the crack front, while the number of element divisions along the arc length of the crack front is user-specified. The remaining conventional brick elements of the model constitute element group II. 3 - Restrictions on the complexity of the problem: Maxima of 5,500 nodes, 4 layers of clad elements

  11. 3D multiplexed immunoplasmonics microscopy.

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-21

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K(+) channel subunit KV1.1) on human cancer CD44(+) EGFR(+) KV1.1(+) MDA-MB-231 cells and reference CD44(-) EGFR(-) KV1.1(+) 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third

  12. Kuvaus 3D-tulostamisesta hammastekniikassa

    OpenAIRE

    Munne, Mauri; Mustonen, Tuomas; Vähäjylkkä, Jaakko

    2013-01-01

    3D-tulostaminen kehittyy nopeasti ja yleistyy koko ajan. Tulostimien tarkkuuksien kehittyessä 3D-tulostus on ottamassa myös jalansijaa hammastekniikan alalta. Tämän opinnäytetyön tarkoituksena on kuvata 3D-tulostamisen tilaa hammastekniikassa. 3D-tulostaminen on Suomessa vielä melko harvinaista, joten opinnäytetyön tavoitteena on koota yhteen kaikki mahdollinen tieto liittyen 3D-tulostamiseen hammastekniikassa. Tavoitteena on myös 3D-tulostimen testaaminen käytännössä aina suun skannaami...

  13. NIF Ignition Target 3D Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O; Marinak, M; Milovich, J; Callahan, D

    2008-11-05

    We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.

  14. 3D multiplexed immunoplasmonics microscopy

    Science.gov (United States)

    Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel

    2016-07-01

    Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed

  15. Crowdsourcing Based 3d Modeling

    Science.gov (United States)

    Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.

    2016-06-01

    Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.

  16. Research on the printability of hydrogels in 3D bioprinting

    Science.gov (United States)

    He, Yong; Yang, Feifei; Zhao, Haiming; Gao, Qing; Xia, Bing; Fu, Jianzhong

    2016-07-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells.

  17. Research on the printability of hydrogels in 3D bioprinting

    Science.gov (United States)

    He, Yong; Yang, FeiFei; Zhao, HaiMing; Gao, Qing; Xia, Bing; Fu, JianZhong

    2016-01-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells. PMID:27436509

  18. Research on the printability of hydrogels in 3D bioprinting.

    Science.gov (United States)

    He, Yong; Yang, FeiFei; Zhao, HaiMing; Gao, Qing; Xia, Bing; Fu, JianZhong

    2016-01-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells. PMID:27436509

  19. Eesti 3D jaoks kitsas / Virge Haavasalu

    Index Scriptorium Estoniae

    Haavasalu, Virge

    2009-01-01

    Produktsioonifirma Digitaalne Sputnik: Kaur ja Kaspar Kallas tegelevad filmide produtseerimise ning 3D digitaalkaamerate tootearendusega (Silicon Imaging LLC). Vendade Kallaste 3D-kaamerast. Kommenteerib Eesti Filmi Sihtasutuse direktor Marge Liiske

  20. Will 3D printers manufacture your meals?

    NARCIS (Netherlands)

    Bommel, K.J.C. van

    2013-01-01

    These days, 3D printers are laying down plastics, metals, resins, and other materials in whatever configurations creative people can dream up. But when the next 3D printing revolution comes, you'll be able to eat it.

  1. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business that has developed 3D Flash LIDAR systems for space and terrestrial applications. 3D Flash LIDAR is...

  2. Comparison of two-transsacral-screw fixation versus triangular osteosynthesis for transforaminal sacral fractures.

    Science.gov (United States)

    Min, Kyong S; Zamorano, David P; Wahba, George M; Garcia, Ivan; Bhatia, Nitin; Lee, Thay Q

    2014-09-01

    Transforaminal pelvic fractures are high-energy injuries that are translationally and rotationally unstable. This study compared the biomechanical stability of triangular osteosynthesis vs 2-transsacral-screw fixation in the repair of a transforaminal pelvic fracture model. A transforaminal fracture model was created in 10 cadaveric lumbopelvic specimens. Five of the specimens were stabilized with triangular osteosynthesis, which consisted of unilateral L5-to-ilium lumbopelvic fixation and ipsilateral iliosacral screw fixation. The remaining 5 were stabilized with a 2-transsacral-screw fixation technique that consisted of 2 transsacral screws inserted across S1. All specimens were loaded cyclically and then loaded to failure. Translation and rotation were measured using the MicroScribe 3D digitizing system (Revware Inc, Raleigh, North Carolina). The 2-transsacral-screw group showed significantly greater stiffness than the triangular osteosynthesis group (2-transsacral-screw group, 248.7 N/mm [standard deviation, 73.9]; triangular osteosynthesis group, 125.0 N/mm [standard deviation, 66.9]; P=.02); however, ultimate load and rotational stiffness were not statistically significant. Compared with triangular osteosynthesis fixation, the use of 2 transsacral screws provides a comparable biomechanical stability profile in both translation and rotation. This newly revised 2-transsacral-screw construct offers the traumatologist an alternative method of repair for vertical shear fractures that provides biplanar stability. It also offers the advantage of percutaneous placement in either the prone or supine position.

  3. Face Detection with a 3D Model

    OpenAIRE

    Barbu, Adrian; Lay, Nathan; Gramajo, Gary

    2014-01-01

    This paper presents a part-based face detection approach where the spatial relationship between the face parts is represented by a hidden 3D model with six parameters. The computational complexity of the search in the six dimensional pose space is addressed by proposing meaningful 3D pose candidates by image-based regression from detected face keypoint locations. The 3D pose candidates are evaluated using a parameter sensitive classifier based on difference features relative to the 3D pose. A...

  4. 3D Additive Manufacturing Symposium & Workshop

    OpenAIRE

    Unver, Ertu; Taylor, Andrew

    2015-01-01

    The IMI /3M BIC 3D Additive Manufacturing Symposium and Workshop was hosted by 3M Buckley Innovation Centre on March 17th 2015. The event was attended by the major players in precision engineering, 3D additive design and manufacturing: Representatives from EOS, Renishaw, HK 3D Printing IMI Plc Senior Management team, design engineers, programmers and academics from the University of Huddersfield School of Art Design & Architecture, 3M Buckley centre 3D printing management and designers shared...

  5. Forward ramp in 3D

    Science.gov (United States)

    1997-01-01

    Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal.The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower left of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At right, a lander petal is visible.The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  6. Triangular buckling patterns of twisted inextensible strips

    CERN Document Server

    Korte, A P; van der Heijden, G H M

    2010-01-01

    When twisting a strip of paper or acetate under high longitudinal tension, one observes, at some critical load, a buckling of the strip into a regular triangular pattern. Very similar triangular facets have recently been observed in solutions to a new set of geometrically-exact equations describing the equilibrium shape of thin inextensible elastic strips. Here we formulate a modified boundary-value problem for these equations and construct post-buckling solutions in good agreement with the observed pattern in twisted strips. We also study the force-extension and moment-twist behaviour of these strips by varying the mode number n of triangular facets.

  7. 3D modelling for multipurpose cadastre

    NARCIS (Netherlands)

    Abduhl Rahman, A.; Van Oosterom, P.J.M.; Hua, T.C.; Sharkawi, K.H.; Duncan, E.E.; Azri, N.; Hassan, M.I.

    2012-01-01

    Three-dimensional (3D) modelling of cadastral objects (such as legal spaces around buildings, around utility networks and other spaces) is one of the important aspects for a multipurpose cadastre (MPC). This paper describes the 3D modelling of the objects for MPC and its usage to the knowledge of 3D

  8. Beowulf 3D: a case study

    Science.gov (United States)

    Engle, Rob

    2008-02-01

    This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.

  9. 3D Printing and Its Urologic Applications.

    Science.gov (United States)

    Soliman, Youssef; Feibus, Allison H; Baum, Neil

    2015-01-01

    3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology.

  10. Expanding Geometry Understanding with 3D Printing

    Science.gov (United States)

    Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi

    2016-01-01

    With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…

  11. MOM3D/EM-ANIMATE - MOM3D WITH ANIMATION CODE

    Science.gov (United States)

    Shaeffer, J. F.

    1994-01-01

    MOM3D (LAR-15074) is a FORTRAN method-of-moments electromagnetic analysis algorithm for open or closed 3-D perfectly conducting or resistive surfaces. Radar cross section with plane wave illumination is the prime analysis emphasis; however, provision is also included for local port excitation for computing antenna gain patterns and input impedances. The Electric Field Integral Equation form of Maxwell's equations is solved using local triangle couple basis and testing functions with a resultant system impedance matrix. The analysis emphasis is not only for routine RCS pattern predictions, but also for phenomenological diagnostics: bistatic imaging, currents, and near scattered/total electric fields. The images, currents, and near fields are output in form suitable for animation. MOM3D computes the full backscatter and bistatic radar cross section polarization scattering matrix (amplitude and phase), body currents and near scattered and total fields for plane wave illumination. MOM3D also incorporates a new bistatic k space imaging algorithm for computing down range and down/cross range diagnostic images using only one matrix inversion. MOM3D has been made memory and cpu time efficient by using symmetric matrices, symmetric geometry, and partitioned fixed and variable geometries suitable for design iteration studies. MOM3D may be run interactively or in batch mode on 486 IBM PCs and compatibles, UNIX workstations or larger computers. A 486 PC with 16 megabytes of memory has the potential to solve a 30 square wavelength (containing 3000 unknowns) symmetric configuration. Geometries are described using a triangular mesh input in the form of a list of spatial vertex points and a triangle join connection list. The EM-ANIMATE (LAR-15075) program is a specialized visualization program that displays and animates the near-field and surface-current solutions obtained from an electromagnetics program, in particular, that from MOM3D. The EM-ANIMATE program is windows based and

  12. Investigating Mobile Stereoscopic 3D Touchscreen Interaction

    OpenAIRE

    Colley, Ashley; Hakkila, Jonna; SCHOENING, Johannes; Posti, Maaret

    2013-01-01

    3D output is no longer limited to large screens in cinemas or living rooms. Nowadays more and more mobile devices are equipped with autostereoscopic 3D (S3D) touchscreens. As a consequence interaction with 3D content now also happens whilst users are on the move. In this paper we carried out a user study with 27 participants to assess how mobile interaction, i.e. whilst walking, with mobile S3D devices, differs from interaction with 2D mobile touchscreens. We investigate the difference in tou...

  13. User-centered 3D geovisualisation

    DEFF Research Database (Denmark)

    Nielsen, Anette Hougaard

    2004-01-01

    . In a broader perspective, the overall aim is to develop a language in 3D Geovisualisation gained through usability projects and the development of a theoretical background. A conceptual level of user-centered 3D Geovisualisation is introduced by applying a categorisation originating from Virtual Reality......3D Geovisualisation is a multidisciplinary science mainly utilizing geographically related data, developing software systems for 3D visualisation and producing relevant models. In this paper the connection between geoinformation stored as 3D objects and the end user is of special interest...

  14. Wafer level 3-D ICs process technology

    CERN Document Server

    Tan, Chuan Seng; Reif, L Rafael

    2009-01-01

    This book focuses on foundry-based process technology that enables the fabrication of 3-D ICs. The core of the book discusses the technology platform for pre-packaging wafer lever 3-D ICs. However, this book does not include a detailed discussion of 3-D ICs design and 3-D packaging. This is an edited book based on chapters contributed by various experts in the field of wafer-level 3-D ICs process technology. They are from academia, research labs and industry.

  15. View-based 3-D object retrieval

    CERN Document Server

    Gao, Yue

    2014-01-01

    Content-based 3-D object retrieval has attracted extensive attention recently and has applications in a variety of fields, such as, computer-aided design, tele-medicine,mobile multimedia, virtual reality, and entertainment. The development of efficient and effective content-based 3-D object retrieval techniques has enabled the use of fast 3-D reconstruction and model design. Recent technical progress, such as the development of camera technologies, has made it possible to capture the views of 3-D objects. As a result, view-based 3-D object retrieval has become an essential but challenging res

  16. Esiselvitys elintarvikkeiden 3D-tulostamisesta

    OpenAIRE

    Teva, Arno

    2015-01-01

    Opinnäytetyön tavoitteena oli laatia esiselvitys 3D-tulostamisesta elintarvikealalla. 3D-tulostaminen on uusi ja jatkuvasti kehittyvä ala, joka tulee vaikuttamaan myös elintarvikealan kehittymiseen. Työn tarkoituksena oli selvittää elintarvikenäkökulmasta 3D-tulostamiseen liittyviä tekijöitä. Aiheen toimeksiantajana oli Hämeen ammattikorkeakoulu ja kohderyhmänä elintarvikealan Pk-yritykset. Opinnäytetyössä esitellään yleisimpiä 3D-tulostusmenetelmiä ja selvitetään 3D-tulostamista tietokone...

  17. PRIPRAVA MODELOV ZA 3D - TISK

    OpenAIRE

    Črešnik, Igor

    2015-01-01

    V diplomskem delu predstavljamo pripravo modela na 3D-tisk. V prvem delu smo preleteli zgodovino tiska. Predstavili smo tehnologijo 3D-tiska ter različne tehnike tiskanja, ki jih uporabljajo določeni tiskalniki. V nadaljevanju smo pregledali različne tipe 3D-tiskalnikov, ki se uporabljajo za domačo ali komercialno uporabo ter izpostavili njihove prednosti in slabosti. V zadnjem delu diplomskega dela smo na praktičnem primeru 3D-modela hiše prikazali proces priprave modela za 3D-tisk. Pri delu...

  18. 3D-tulostimien tutkiminen painotalolle

    OpenAIRE

    Toivonen, Aleksi

    2014-01-01

    Opinnäytetyön tavoitteena oli perehtyä 3D-tulostamiseen ja tutkia painotaloon sopivia 3D-tulostimia ja 3D-tulostamiseen liittyviä tekniikoita. Opinnäytetyön tavoitteena oli myös pohtia painotalolle mahdollisia 3D-tulostamiseen liittyviä tuotekonsepteja yrityksille ja yksityisille kuluttajille. Painoalan yrityksen tarkoituksena on sijoittaa lähitulevaisuudessa 3D-tulostimeen, joten opinnäytetyö oli ajankohtainen tutkimustyö yritykselle. Opinnäytetyön toimeksiantajana toimi painoalan yritys. ...

  19. BUILDING A HOMEMADE 3D PRINTER

    OpenAIRE

    Tunc, Baran

    2015-01-01

    3D printing has been attracted much attention around the world due to its high potential of new application fields. In this respect, developing and inventing new filament materials for 3D printers or new techniques of 3D printing are the main interest of the many materials scientists. This paper reports a comprehensive overview of 3D printing followed by a summary of my ongoing study of building a composite homemade 3D printer. At this stage of this study, a CNC router was successfully conver...

  20. 3D Printing our future: Now

    OpenAIRE

    Taylor, Andrew; Unver, Ertu

    2015-01-01

    This 3D Printing our Future:Now talk and visual presentation was given to delegates at the IMI 3D Workshop held at 3M Buckley Innovation Centre on 17th March 2015. The event was hosted by 3Mbuckley Innovation Centre for IMI plc a global engineering company, 3M, and leading 3D additive manufacturing technology providers: EOS, Renishaw and HK 3D printing to disseminate and share their experience on the latest 3D additive design and manufacturing technologies available to the engineering an...

  1. Properties of plane discrete Poisson-Voronoi tessellations on triangular tiling formed by the Kolmogorov-Johnson-Mehl-Avrami growth of triangular islands

    Science.gov (United States)

    Korobov, A.

    2011-08-01

    Discrete uniform Poisson-Voronoi tessellations of two-dimensional triangular tilings resulting from the Kolmogorov-Johnson-Mehl-Avrami (KJMA) growth of triangular islands have been studied. This shape of tiles and islands, rarely considered in the field of random tessellations, is prompted by the birth-growth process of Ir(210) faceting. The growth mode determines a triangular metric different from the Euclidean metric. Kinetic characteristics of tessellations appear to be metric sensitive, in contrast to area distributions. The latter have been studied for the variant of nuclei growth to the first impingement in addition to the conventional case of complete growth. Kiang conjecture works in both cases. The averaged number of neighbors is six for all studied densities of random tessellations, but neighbors appear to be mainly different in triangular and Euclidean metrics. Also, the applicability of the obtained results for simulating birth-growth processes when the 2D nucleation and impingements are combined with the 3D growth in the particular case of similar shape and the same orientation of growing nuclei is briefly discussed.

  2. Properties of plane discrete Poisson-Voronoi tessellations on triangular tiling formed by the Kolmogorov-Johnson-Mehl-Avrami growth of triangular islands.

    Science.gov (United States)

    Korobov, A

    2011-08-01

    Discrete uniform Poisson-Voronoi tessellations of two-dimensional triangular tilings resulting from the Kolmogorov-Johnson-Mehl-Avrami (KJMA) growth of triangular islands have been studied. This shape of tiles and islands, rarely considered in the field of random tessellations, is prompted by the birth-growth process of Ir(210) faceting. The growth mode determines a triangular metric different from the Euclidean metric. Kinetic characteristics of tessellations appear to be metric sensitive, in contrast to area distributions. The latter have been studied for the variant of nuclei growth to the first impingement in addition to the conventional case of complete growth. Kiang conjecture works in both cases. The averaged number of neighbors is six for all studied densities of random tessellations, but neighbors appear to be mainly different in triangular and Euclidean metrics. Also, the applicability of the obtained results for simulating birth-growth processes when the 2D nucleation and impingements are combined with the 3D growth in the particular case of similar shape and the same orientation of growing nuclei is briefly discussed.

  3. Triangular nanobeam photonic cavities in single crystal diamond

    CERN Document Server

    Bayn, Igal; Salzman, Joseph; Kalish, Rafi

    2011-01-01

    Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel triangular cross section nanobeam cavity produced in a single crystal diamond is demonstrated. The present cavity design, based on a triangular cross section allows vertical confinement and better signal collection efficiency than that of slab-based nanocavities, and eliminates the need for a pre-existing membrane. The nanobeam is fabricated by Focused-Ion-Beam (FIB) patterning. The cavity is characterized by a confocal photoluminescence. The modes display quality factors of Q ~220 and are deviated in wavelength by only ~1.7nm from the NV- color center zero phonon line (ZPL). The measured results are found in good agreement with 3D Finite-Difference-Time-Domain (FDTD) calculations. A more advanced cavity design with Q=22,000 is model...

  4. Web-based interactive visualization of 3D video mosaics using X3D standard

    Institute of Scientific and Technical Information of China (English)

    CHON Jaechoon; LEE Yang-Won; SHIBASAKI Ryosuke

    2006-01-01

    We present a method of 3D image mosaicing for real 3D representation of roadside buildings, and implement a Web-based interactive visualization environment for the 3D video mosaics created by 3D image mosaicing. The 3D image mosaicing technique developed in our previous work is a very powerful method for creating textured 3D-GIS data without excessive data processing like the laser or stereo system. For the Web-based open access to the 3D video mosaics, we build an interactive visualization environment using X3D, the emerging standard of Web 3D. We conduct the data preprocessing for 3D video mosaics and the X3D modeling for textured 3D data. The data preprocessing includes the conversion of each frame of 3D video mosaics into concatenated image files that can be hyperlinked on the Web. The X3D modeling handles the representation of concatenated images using necessary X3D nodes. By employing X3D as the data format for 3D image mosaics, the real 3D representation of roadside buildings is extended to the Web and mobile service systems.

  5. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

    Science.gov (United States)

    Handy Turner, Tara

    2010-02-01

    From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

  6. Molecular rectification in triangularly shaped graphene nanoribbons.

    Science.gov (United States)

    Liu, Hongmei; Wang, Hongbo; Zhao, Jianwei; Kiguchi, Manabu

    2013-02-15

    We present a theoretical study of electron transport in tailored zigzag graphene nanoribbons (ZGNRs) with triangular structure using density functional theory together with the nonequilibrium Green's function formalism. We find significant rectification with a favorite electron transfer direction from the vertex to the right edge. The triangular ZGNR connecting to the electrode with one thiol group at each terminal shows an average rectification ratio of 8.4 over the bias range from -1.0 to 1.0 V. This asymmetric electron transport property originates from nearly zero band gap of triangular ZGNR under negative bias, whereas a band gap opens under positive bias. When the molecule is connected to the electrode by multithiol groups, the current is enhanced due to strong interfacial coupling; however, the rectification ratio decreases. The simulation results indicate that the unique electronic states of triangular ZGNR are responsible for rectification, rather than the asymmetric anchoring groups.

  7. Functional Contractive Maps in Triangular Symmetric Spaces

    Directory of Open Access Journals (Sweden)

    Mihai Turinici

    2013-01-01

    Full Text Available Some fixed point results are given for a class of functional contractions acting on (reflexive triangular symmetric spaces. Technical connections with the corresponding theories over (standard metric and partial metric spaces are also being established.

  8. RELAP5-3D User Problems

    Energy Technology Data Exchange (ETDEWEB)

    Riemke, Richard Allan

    2002-09-01

    The Reactor Excursion and Leak Analysis Program with 3D capability1 (RELAP5-3D) is a reactor system analysis code that has been developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the U. S. Department of Energy (DOE). The 3D capability in RELAP5-3D includes 3D hydrodynamics2 and 3D neutron kinetics3,4. Assessment, verification, and validation of the 3D capability in RELAP5-3D is discussed in the literature5,6,7,8,9,10. Additional assessment, verification, and validation of the 3D capability of RELAP5-3D will be presented in other papers in this users seminar. As with any software, user problems occur. User problems usually fall into the categories of input processing failure, code execution failure, restart/renodalization failure, unphysical result, and installation. This presentation will discuss some of the more generic user problems that have been reported on RELAP5-3D as well as their resolution.

  9. 3D laptop for defense applications

    Science.gov (United States)

    Edmondson, Richard; Chenault, David

    2012-06-01

    Polaris Sensor Technologies has developed numerous 3D display systems using a US Army patented approach. These displays have been developed as prototypes for handheld controllers for robotic systems and closed hatch driving, and as part of a TALON robot upgrade for 3D vision, providing depth perception for the operator for improved manipulation and hazard avoidance. In this paper we discuss the prototype rugged 3D laptop computer and its applications to defense missions. The prototype 3D laptop combines full temporal and spatial resolution display with the rugged Amrel laptop computer. The display is viewed through protective passive polarized eyewear, and allows combined 2D and 3D content. Uses include robot tele-operation with live 3D video or synthetically rendered scenery, mission planning and rehearsal, enhanced 3D data interpretation, and simulation.

  10. 3D Chaotic Functions for Image Encryption

    Directory of Open Access Journals (Sweden)

    Pawan N. Khade

    2012-05-01

    Full Text Available This paper proposes the chaotic encryption algorithm based on 3D logistic map, 3D Chebyshev map, and 3D, 2D Arnolds cat map for color image encryption. Here the 2D Arnolds cat map is used for image pixel scrambling and 3D Arnolds cat map is used for R, G, and B component substitution. 3D Chebyshev map is used for key generation and 3D logistic map is used for image scrambling. The use of 3D chaotic functions in the encryption algorithm provide more security by using the, shuffling and substitution to the encrypted image. The Chebyshev map is used for public key encryption and distribution of generated private keys.

  11. High Current Density 2D/3D Esaki Tunnel Diodes

    OpenAIRE

    Krishnamoorthy, Sriram; Lee II, Edwin W.; Lee, Choong Hee; Zhang, Yuewei; McCulloch, William D.; Johnson, Jared M.; Hwang, Jinwoo; Wu, Yiying; Rajan, Siddharth

    2016-01-01

    The integration of two-dimensional materials such as transition metal dichalcogenides with bulk semiconductors offer interesting opportunities for 2D/3D heterojunction-based novel device structures without any constraints of lattice matching. By exploiting the favorable band alignment at the GaN/MoS2 heterojunction, an Esaki interband tunnel diode is demonstrated by transferring large area, Nb-doped, p-type MoS2 onto heavily n-doped GaN. A peak current density of 446 A/cm2 with repeatable roo...

  12. Magnetic phase diagrams of classical triangular and kagome antiferromagnets

    Energy Technology Data Exchange (ETDEWEB)

    Gvozdikova, M V [Department of Physics, Kharkov National University, 61077 Kharkov (Ukraine); Melchy, P-E; Zhitomirsky, M E, E-mail: mike.zhitomirsky@cea.fr [Service de Physique Statistique, Magnetisme et Supraconductivite, UMR-E9001 CEA-INAC/UJF, 17 rue des Martyrs, 38054 Grenoble (France)

    2011-04-27

    We investigate the effect of geometrical frustration on the H-T phase diagrams of the classical Heisenberg antiferromagnets on triangular and kagome lattices. The phase diagrams for the two models are obtained from large-scale Monte Carlo simulations. For the kagome antiferromagnet, thermal fluctuations are unable to lift degeneracy completely and stabilize translationally disordered multipolar phases. We find a substantial difference in the temperature scales of the order by disorder effect related to different degeneracy of the low- and the high-field classical ground states in the kagome antiferromagnet. In the low-field regime, the Kosterlitz-Thouless transition into a spin-nematic phase is produced by unbinding of half-quantum vortices.

  13. 3-D Technology Approaches for Biological Ecologies

    Science.gov (United States)

    Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team

    Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).

  14. FROM 3D MODEL DATA TO SEMANTICS

    Directory of Open Access Journals (Sweden)

    My Abdellah Kassimi

    2012-01-01

    Full Text Available The semantic-based 3D models retrieval systems have become necessary since the increase of 3D modelsdatabases. In this paper, we propose a new method for the mapping problem between 3D model data andsemantic data involved in semantic based retrieval for 3D models given by polygonal meshes. First, wefocused on extracting invariant descriptors from the 3D models and analyzing them to efficient semanticannotation and to improve the retrieval accuracy. Selected shape descriptors provide a set of termscommonly used to describe visually a set of objects using linguistic terms and are used as semanticconcept to label 3D model. Second, spatial relationship representing directional, topological anddistance relationships are used to derive other high-level semantic features and to avoid the problem ofautomatic 3D model annotation. Based on the resulting semantic annotation and spatial concepts, anontology for 3D model retrieval is constructed and other concepts can be inferred. This ontology is usedto find similar 3D models for a given query model. We adopted the query by semantic example approach,in which the annotation is performed mostly automatically. The proposed method is implemented in our3D search engine (SB3DMR, tested using the Princeton Shape Benchmark Database.

  15. Automatic 3D video format detection

    Science.gov (United States)

    Zhang, Tao; Wang, Zhe; Zhai, Jiefu; Doyen, Didier

    2011-03-01

    Many 3D formats exist and will probably co-exist for a long time even if 3D standards are today under definition. The support for multiple 3D formats will be important for bringing 3D into home. In this paper, we propose a novel and effective method to detect whether a video is a 3D video or not, and to further identify the exact 3D format. First, we present how to detect those 3D formats that encode a pair of stereo images into a single image. The proposed method detects features and establishes correspondences between features in the left and right view images, and applies the statistics from the distribution of the positional differences between corresponding features to detect the existence of a 3D format and to identify the format. Second, we present how to detect the frame sequential 3D format. In the frame sequential 3D format, the feature points are oscillating from frame to frame. Similarly, the proposed method tracks feature points over consecutive frames, computes the positional differences between features, and makes a detection decision based on whether the features are oscillating. Experiments show the effectiveness of our method.

  16. 3D Systems” ‘Stuck in the Middle’ of the 3D Printer Boom?

    NARCIS (Netherlands)

    A. Hoffmann (Alan)

    2014-01-01

    textabstract3D Systems, the pioneer of 3D printing, predicted a future where "kids from 8 to 80" could design and print their ideas at home. By 2013, 9 years after the creation of the first working 3D printer, there were more than 30 major 3D printing companies competing for market share. 3DS and it

  17. 3D-tulostus : case Printrbot

    OpenAIRE

    Arvekari, Lassi

    2013-01-01

    Opinnäytetyön tavoitteena on selvittää 3D-tulostustekniikan perusteita ja 3D-tulostuksen nykytilannetta. 3D-tulostukseen sopivien mallien luomista tutkitaan ja mallin tekemiseen on etsitty toimivia ohjesääntöjä. Tärkeä osa työtä on tutkia mitä vaiheita 3D-tulostimen hankinnassa kotikäyttöön tulee vastaan. Käytännön kokeita varten opinnäytetyössä on case Printrbot, jossa on tutustuttu edulliseen 3D-tulostuslaitteeseen kokoonpanosta lähtien. Työn kuluessa selvisi että edulliset 3D-tulos...

  18. Wave propagation in fractal-inspired self-similar beam lattices

    International Nuclear Information System (INIS)

    We combine numerical analysis and experiments to investigate the effect of hierarchy on the propagation of elastic waves in triangular beam lattices. While the response of the triangular lattice is characterized by a locally resonant band gap, both Bragg-type and locally resonant gaps are found for the hierarchical lattice. Therefore, our results demonstrate that structural hierarchy can be exploited to introduce an additional type of band gaps, providing a robust strategy for the design of lattice-based metamaterials with hybrid band gap properties (i.e., possessing band gaps that arises from both Bragg scattering and localized resonance)

  19. Wave propagation in fractal-inspired self-similar beam lattices

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Qi Jian [Engineering Science Programme, National University of Singapore, Singapore 117576 (Singapore); Wang, Pai [Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Koh, Soo Jin Adrian [Engineering Science Programme, National University of Singapore, Singapore 117576 (Singapore); Department of Mechanical Engineering, National University of Singapore, Singapore 117576 (Singapore); Khoo, Eng Huat [Engineering Science Programme, National University of Singapore, Singapore 117576 (Singapore); A*STAR Institute of High Performance Computing, Singapore 138632 (Singapore); Bertoldi, Katia [Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kavli Institute, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-11-30

    We combine numerical analysis and experiments to investigate the effect of hierarchy on the propagation of elastic waves in triangular beam lattices. While the response of the triangular lattice is characterized by a locally resonant band gap, both Bragg-type and locally resonant gaps are found for the hierarchical lattice. Therefore, our results demonstrate that structural hierarchy can be exploited to introduce an additional type of band gaps, providing a robust strategy for the design of lattice-based metamaterials with hybrid band gap properties (i.e., possessing band gaps that arises from both Bragg scattering and localized resonance)

  20. Spatial data modelling for 3D GIS

    CERN Document Server

    Abdul-Rahman, Alias

    2007-01-01

    This book covers fundamental aspects of spatial data modelling specifically on the aspect of three-dimensional (3D) modelling and structuring. Realisation of ""true"" 3D GIS spatial system needs a lot of effort, and the process is taking place in various research centres and universities in some countries. The development of spatial data modelling for 3D objects is the focus of this book.

  1. Compression of 3D models with NURBS

    OpenAIRE

    Santa Cruz Ducci, Diego; Ebrahimi, Touradj

    2005-01-01

    With recent progress in computing, algorithmics and telecommunications, 3D models are increasingly used in various multimedia applications. Examples include visualization, gaming, entertainment and virtual reality. In the multimedia domain 3D models have been traditionally represented as polygonal meshes. This piecewise planar representation can be thought of as the analogy of bitmap images for 3D surfaces. As bitmap images, they enjoy great flexibility and are particularly well suited to des...

  2. Extraordinary 3D Surface Materials: A practice based exhibition of 3D learning artefacts and prototypes.

    OpenAIRE

    Taylor, Andrew; Harris, Joanne; Unver, Ertu; Lewis, Linda

    2011-01-01

    A collection of 3D prototyped research learning artefacts were exhibited at Surface Design Show 2011. The artefacts on display provided tacit evidence of the 3D concept modelling and reflective learning experiences of a final year BA (Hons) Surface Design for Fashion & Interiors student group using 3D polygon modelling software and additive prototyping technologies (3D Printing) for the first time. The student authored project blog http://extraordinary-3d-materials.blogspot.co.uk/ documen...

  3. 3D modelling for multipurpose cadastre

    OpenAIRE

    Abduhl Rahman, A.; P. J. M. Van Oosterom; T. C. Hua; Sharkawi, K.H.; E. E. Duncan; Azri, N.; Hassan, M. I.

    2012-01-01

    Three-dimensional (3D) modelling of cadastral objects (such as legal spaces around buildings, around utility networks and other spaces) is one of the important aspects for a multipurpose cadastre (MPC). This paper describes the 3D modelling of the objects for MPC and its usage to the knowledge of 3D cadastre since more and more related agencies attempt to develop or embed 3D components into the MPC. We also intend to describe the initiative by Malaysian national mapping and cadastral agency (...

  4. Getting started in 3D with Maya

    CERN Document Server

    Watkins, Adam

    2012-01-01

    Deliver professional-level 3D content in no time with this comprehensive guide to 3D animation with Maya. With over 12 years of training experience, plus several award winning students under his belt, author Adam Watkins is the ideal mentor to get you up to speed with 3D in Maya. Using a structured and pragmatic approach Getting Started in 3D with Maya begins with basic theory of fundamental techniques, then builds on this knowledge using practical examples and projects to put your new skills to the test. Prepared so that you can learn in an organic fashion, each chapter builds on the know

  5. Can 3D Printing change your business?

    OpenAIRE

    Unver, Ertu

    2013-01-01

    This presentation is given to businesses / companies with an interest in 3D Printing and Additive Manufacturing in West Yorkshire, UK Organised by the Calderdale and Kirklees Manufacturing Alliance. http://www.ckma.co.uk/ by Dr Ertu Unver Senior Lecturer / Product Design / MA 3D Digital Design / University of Huddersfield Location : 3M BIC, Date : 11th April, Time : 5.30 – 8pm Additive manufacturing or 3D printing is a process of making a three-dimensional (3D) objects from...

  6. A 3d game in python

    OpenAIRE

    Xu, Minghui

    2014-01-01

    3D game has widely been accepted and loved by many game players. More and more different kinds of 3D games were developed to feed people’s needs. The most common programming language for development of 3D game is C++ nowadays. Python is a high-level scripting language. It is simple and clear. The concise syntax could speed up the development cycle. This project was to develop a 3D game using only Python. The game is about how a cat lives in the street. In order to live, the player need...

  7. Virtual Realization using 3D Password

    Directory of Open Access Journals (Sweden)

    A.B.Gadicha

    2012-03-01

    Full Text Available Current authentication systems suffer from many weaknesses. Textual passwords are commonly used; however, users do not follow their requirements. Users tend to choose meaningful words from dictionaries, which make textual passwords easy to break and vulnerable to dictionary or brute force attacks. Many available graphical passwords have a password space that is less than or equal to the textual password space. Smart cards or tokens can be stolen. Many biometric authentications have been proposed; however, users tend to resist using biometrics because of their intrusiveness and the effect on their privacy. Moreover, biometrics cannot be revoked. In this paper, we present and evaluate our contribution, i.e., the 3D password. The 3D password is a multifactor authentication scheme. To be authenticated, we present a 3D virtual environment where the user navigates and interacts with various objects. The sequence of actions and interactions toward the objects inside the 3D environment constructs the user’s 3D password. The 3D password can combine most existing authentication schemes such as textual passwords, graphical passwords, and various types of biometrics into a 3D virtual environment. The design of the 3D virtual environment and the type of objects selected determine the 3D password key space.

  8. Calibration for 3D Structured Light Measurement

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A calibration procedure was developed for three-dimensional(3D) binocular structured light measurement systems. In virtue of a specially designed pattern, matching points in stereo images are extracted. And then sufficient 3D space points are obtained through pairs of images with the intrinsic and extrinsic parameters of each camera estimated prior and consequently some lights are calibrated by means of multi point fitting. Finally, a mathematical model is applied to interpolate and approximate all dynamic scanning lights based on geometry. The process of calibration method is successfully used in the binocular 3D measurement system based on structured lights and the 3D reconstruction results are satisfying.

  9. Dimensional accuracy of 3D printed vertebra

    Science.gov (United States)

    Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can

    2014-03-01

    3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.

  10. 3D Printing Making the Digital Real .

    OpenAIRE

    Miss Prachi More

    2013-01-01

    3D printing is quickly expanding field, with the popularity and uses for 3D printers growing every day. 3D printing can be used to prototype, create replacement parts, and is even versatile enough to print prostheses and medical implants. It will have a growing impact on our world, as more and more people gain access to these amazing machines.[1] In this article, we would like to attempt to give an introduction of the technology. 3Dimensions printing is a method of converting a virtual 3D mod...

  11. 3D-tulostuksen viipalointiohjelmien vertailu

    OpenAIRE

    Virolainen, Ville

    2015-01-01

    Opinnäytetyön tavoitteena on selventää 3D-tulostamisen prosessia yksityisen käyttäjän näkökulmasta sekä luoda testitulostuksia, joiden perusteella pystytään vertailemaan prosessissa käytettävien viipalointiohjelmien toimintaa keskenään. Työssä perehdytään aluksi 3D-tulostuksen teoriataustaan, jonka jälkeen suoritetaan 3D-tulostimella testitulostukset käyttäen kolmea eri viipalointiohjelmaa. 3D-tulostamisella tarkoitetaan prosessia, jonka tarkoituksena on luoda kolmiulotteinen objekti käyt...

  12. Illustrating Mathematics using 3D Printers

    OpenAIRE

    Knill, Oliver; Slavkovsky, Elizabeth

    2013-01-01

    3D printing technology can help to visualize proofs in mathematics. In this document we aim to illustrate how 3D printing can help to visualize concepts and mathematical proofs. As already known to educators in ancient Greece, models allow to bring mathematics closer to the public. The new 3D printing technology makes the realization of such tools more accessible than ever. This is an updated version of a paper included in book Low-Cost 3D Printing for science, education and Sustainable Devel...

  13. BIM tietomalli ja 3D-tulostus

    OpenAIRE

    Myllykoski, Joonas; Palonen, Teemu

    2015-01-01

    Tämän opinnäytetyön tavoitteena oli selvittää miten Tekla Structures ohjelmalla luotu 3D-malli saadaan tulostettua koulun 3D-tulostimella sekä tutkittiin voidaanko Tekla Structuresin ominaisuuksia hyödyntää 3D-tulostamisessa ja miten tulostus onnistuu autocadilla. Selvitimme myös mahdollisia 3D-tulostusteknologian sovelluksia tulevaisuuden rakennustuotannossa ja sen näkymiä rakennusteollisuudessa sekä erilaisia tulostus menetelmiä joita voitaisiin mahdollisesti hyödyntää rakennusteollisuudess...

  14. FastScript3D - A Companion to Java 3D

    Science.gov (United States)

    Koenig, Patti

    2005-01-01

    FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.

  15. Directing Matter: Toward Atomic-Scale 3D Nanofabrication.

    Science.gov (United States)

    Jesse, Stephen; Borisevich, Albina Y; Fowlkes, Jason D; Lupini, Andrew R; Rack, Philip D; Unocic, Raymond R; Sumpter, Bobby G; Kalinin, Sergei V; Belianinov, Alex; Ovchinnikova, Olga S

    2016-06-28

    Enabling memristive, neuromorphic, and quantum-based computing as well as efficient mainstream energy storage and conversion technologies requires the next generation of materials customized at the atomic scale. This requires full control of atomic arrangement and bonding in three dimensions. The last two decades witnessed substantial industrial, academic, and government research efforts directed toward this goal through various lithographies and scanning-probe-based methods. These technologies emphasize 2D surface structures, with some limited 3D capability. Recently, a range of focused electron- and ion-based methods have demonstrated compelling alternative pathways to achieving atomically precise manufacturing of 3D structures in solids, liquids, and at interfaces. Electron and ion microscopies offer a platform that can simultaneously observe dynamic and static structures at the nano- and atomic scales and also induce structural rearrangements and chemical transformation. The addition of predictive modeling or rapid image analytics and feedback enables guiding these in a controlled manner. Here, we review the recent results that used focused electron and ion beams to create free-standing nanoscale 3D structures, radiolysis, and the fabrication potential with liquid precursors, epitaxial crystallization of amorphous oxides with atomic layer precision, as well as visualization and control of individual dopant motion within a 3D crystal lattice. These works lay the foundation for approaches to directing nanoscale level architectures and offer a potential roadmap to full 3D atomic control in materials. In this paper, we lay out the gaps that currently constrain the processing range of these platforms, reflect on indirect requirements, such as the integration of large-scale data analysis with theory, and discuss future prospects of these technologies. PMID:27183171

  16. Directing Matter: Toward Atomic-Scale 3D Nanofabrication.

    Science.gov (United States)

    Jesse, Stephen; Borisevich, Albina Y; Fowlkes, Jason D; Lupini, Andrew R; Rack, Philip D; Unocic, Raymond R; Sumpter, Bobby G; Kalinin, Sergei V; Belianinov, Alex; Ovchinnikova, Olga S

    2016-06-28

    Enabling memristive, neuromorphic, and quantum-based computing as well as efficient mainstream energy storage and conversion technologies requires the next generation of materials customized at the atomic scale. This requires full control of atomic arrangement and bonding in three dimensions. The last two decades witnessed substantial industrial, academic, and government research efforts directed toward this goal through various lithographies and scanning-probe-based methods. These technologies emphasize 2D surface structures, with some limited 3D capability. Recently, a range of focused electron- and ion-based methods have demonstrated compelling alternative pathways to achieving atomically precise manufacturing of 3D structures in solids, liquids, and at interfaces. Electron and ion microscopies offer a platform that can simultaneously observe dynamic and static structures at the nano- and atomic scales and also induce structural rearrangements and chemical transformation. The addition of predictive modeling or rapid image analytics and feedback enables guiding these in a controlled manner. Here, we review the recent results that used focused electron and ion beams to create free-standing nanoscale 3D structures, radiolysis, and the fabrication potential with liquid precursors, epitaxial crystallization of amorphous oxides with atomic layer precision, as well as visualization and control of individual dopant motion within a 3D crystal lattice. These works lay the foundation for approaches to directing nanoscale level architectures and offer a potential roadmap to full 3D atomic control in materials. In this paper, we lay out the gaps that currently constrain the processing range of these platforms, reflect on indirect requirements, such as the integration of large-scale data analysis with theory, and discuss future prospects of these technologies.

  17. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D

    Science.gov (United States)

    Slaby, Mark-Fabian; Reimann, Rüdiger

    2013-04-01

    In geology, 3D modeling has become very important. In the past, two-dimensional data such as isolines, drilling profiles, or cross-sections based on those, were used to illustrate the subsurface geology, whereas now, we can create complex digital 3D models. These models are produced with special software, such as GOCAD ®. The models can be viewed, only through the software used to create them, or through viewers available for free. The platform-independent PDF (Portable Document Format), enforced by Adobe, has found a wide distribution. This format has constantly evolved over time. Meanwhile, it is possible to display CAD data in an Adobe 3D PDF file with the free Adobe Reader (version 7). In a 3D PDF, a 3D model is freely rotatable and can be assembled from a plurality of objects, which can thus be viewed from all directions on their own. In addition, it is possible to create moveable cross-sections (profiles), and to assign transparency to the objects. Based on industry-standard CAD software, 3D PDFs can be generated from a large number of formats, or even be exported directly from this software. In geoinformatics, different approaches to creating 3D PDFs exist. The intent of the Authority for Mining, Energy and Geology to allow free access to the models of the Geotectonic Atlas (GTA3D), could not be realized with standard software solutions. A specially designed code converts the 3D objects to VRML (Virtual Reality Modeling Language). VRML is one of the few formats that allow using image files (maps) as textures, and to represent colors and shapes correctly. The files were merged in Acrobat X Pro, and a 3D PDF was generated subsequently. A topographic map, a display of geographic directions and horizontal and vertical scales help to facilitate the use.

  18. Emulsion Inks for 3D Printing of High Porosity Materials.

    Science.gov (United States)

    Sears, Nicholas A; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth M

    2016-08-01

    Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water-in-oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer-by-layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure-on-dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques. PMID:27305061

  19. Emulsion Inks for 3D Printing of High Porosity Materials.

    Science.gov (United States)

    Sears, Nicholas A; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth M

    2016-08-01

    Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water-in-oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer-by-layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure-on-dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques.

  20. An aerial 3D printing test mission

    Science.gov (United States)

    Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy

    2016-05-01

    This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.

  1. 3D ultrafast ultrasound imaging in vivo

    International Nuclear Information System (INIS)

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability. (fast track communication)

  2. Ising antiferromagnet on the Archimedean lattices

    Science.gov (United States)

    Yu, Unjong

    2015-06-01

    Geometric frustration effects were studied systematically with the Ising antiferromagnet on the 11 Archimedean lattices using the Monte Carlo methods. The Wang-Landau algorithm for static properties (specific heat and residual entropy) and the Metropolis algorithm for a freezing order parameter were adopted. The exact residual entropy was also found. Based on the degree of frustration and dynamic properties, ground states of them were determined. The Shastry-Sutherland lattice and the trellis lattice are weakly frustrated and have two- and one-dimensional long-range-ordered ground states, respectively. The bounce, maple-leaf, and star lattices have the spin ice phase. The spin liquid phase appears in the triangular and kagome lattices.

  3. Immersive 3D Geovisualization in Higher Education

    Science.gov (United States)

    Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold

    2015-01-01

    In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…

  4. Perception of detail in 3D images

    NARCIS (Netherlands)

    Heyndrickx, I.; Kaptein, R.

    2009-01-01

    A lot of current 3D displays suffer from the fact that their spatial resolution is lower compared to their 2D counterparts. One reason for this is that the multiple views needed to generate 3D are often spatially multiplexed. Besides this, imperfect separation of the left- and right-eye view leads t

  5. 3D printing of functional structures

    NARCIS (Netherlands)

    Krijnen, G.J.M.

    2016-01-01

    The technology colloquial known as ‘3D printing’ has developed in such diversity in printing technologies and application fields that meanwhile it seems anything is possible. However, clearly the ideal 3D Printer, with high resolution, multi-material capability, fast printing, etc. is yet to be deve

  6. Parametrizable cameras for 3D computational steering

    NARCIS (Netherlands)

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  7. 3D Cadastre modelling in Russia

    NARCIS (Netherlands)

    Vandysheva, N.; Tikhonov, V.; Van Oosterom, P.J.M.; Stoter, J.E.; Ploeger, H.D.; Wouters, R.; Penkov, V.

    2011-01-01

    The paper presents the on-going project on 3D cadastre modelling in Russia. The aim of this project is to provide guidance in the development of a prototype and to create favourable legal and institutional conditions for the introduction of 3D cadastre modelling in Russia based on experience of the

  8. Recognition of 3D facial expression dynamics

    NARCIS (Netherlands)

    Sandbach, G.; Zafeiriou, S.; Pantic, Maja; Rueckert, D.

    2012-01-01

    In this paper we propose a method that exploits 3D motion-based features between frames of 3D facial geometry sequences for dynamic facial expression recognition. An expressive sequence is modelled to contain an onset followed by an apex and an offset. Feature selection methods are applied in order

  9. 3-D structures of planetary nebulae

    CERN Document Server

    Steffen, Wolfgang

    2016-01-01

    Recent advances in the 3-D reconstruction of planetary nebulae are reviewed. We include not only results for 3-D reconstructions, but also the current techniques in terms of general methods and software. In order to obtain more accurate reconstructions, we suggest to extend the widely used assumption of homologous nebula expansion to map spectroscopically measured velocity to position along the line of sight.

  10. 3D, or Not to Be?

    Science.gov (United States)

    Norbury, Keith

    2012-01-01

    It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…

  11. 3D Printed Block Copolymer Nanostructures

    Science.gov (United States)

    Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.

    2015-01-01

    The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…

  12. 3D Printing of Molecular Models

    Science.gov (United States)

    Gardner, Adam; Olson, Arthur

    2016-01-01

    Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…

  13. 3D Printing. What's the Harm?

    Science.gov (United States)

    Love, Tyler S.; Roy, Ken

    2016-01-01

    Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…

  14. Multiway calibration in 3D QSAR

    NARCIS (Netherlands)

    Nilsson, J; de Jong, Sietse; Smilde, A

    1997-01-01

    We have introduced multilinear PLS in 3D QSAR and applied it to GRID descriptors from a set of benzamides with affinity to the dopamine D-3 receptor subtype, synthesized as potential drugs against schizophrenia. The key issue in 3D QSAR modelling is to obtain a predictive model that is easy to inter

  15. Limited Feedback for 3D Massive MIMO under 3D-UMa and 3D-UMi Scenarios

    Directory of Open Access Journals (Sweden)

    Zheng Hu

    2015-01-01

    Full Text Available For three-dimensional (3D massive MIMO utilizing the uniform rectangular array (URA in the base station (BS, we propose a limited feedback transmission scheme in which the channel state information (CSI feedback operations for horizontal domain and vertical domain are separate. Compared to the traditional feedback scheme, the scheme can reduce the feedback overhead, code word index search complexity, and storage requirement. Also, based on the zenith of departure angle (ZoD distribution in 3D-Urban Macro Cell (3D-UMa and 3D-Urban Micro Cell (3D-UMi scenarios, we propose the angle quantization codebook for vertical domain, while the codebook of long term evolution-advanced (LTE-Advanced is still adopted in horizontal domain to preserve compatibility with the LTE-Advanced. Based on the angle quantization codebook, the subsampled 3-bit DFT codebook is designed for vertical domain. The system-level simulation results reveal that, to compromise the feedback overhead and system performance, 2-bit codebook for 3D-UMa scenario and 3-bit codebook for 3D-UMi scenario can meet requirements in vertical domain. The feedback period for vertical domain can also be extended appropriately to reduce the feedback overhead.

  16. Density-Based 3D Shape Descriptors

    Directory of Open Access Journals (Sweden)

    Schmitt Francis

    2007-01-01

    Full Text Available We propose a novel probabilistic framework for the extraction of density-based 3D shape descriptors using kernel density estimation. Our descriptors are derived from the probability density functions (pdf of local surface features characterizing the 3D object geometry. Assuming that the shape of the 3D object is represented as a mesh consisting of triangles with arbitrary size and shape, we provide efficient means to approximate the moments of geometric features on a triangle basis. Our framework produces a number of 3D shape descriptors that prove to be quite discriminative in retrieval applications. We test our descriptors and compare them with several other histogram-based methods on two 3D model databases, Princeton Shape Benchmark and Sculpteur, which are fundamentally different in semantic content and mesh quality. Experimental results show that our methodology not only improves the performance of existing descriptors, but also provides a rigorous framework to advance and to test new ones.

  17. Fabrication of 3D Silicon Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; /SINTEF, Oslo; Kenney, C.; Hasi, J.; /SLAC; Da Via, C.; /Manchester U.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  18. Maintaining and troubleshooting your 3D printer

    CERN Document Server

    Bell, Charles

    2014-01-01

    Maintaining and Troubleshooting Your 3D Printer by Charles Bell is your guide to keeping your 3D printer running through preventive maintenance, repair, and diagnosing and solving problems in 3D printing. If you've bought or built a 3D printer such as a MakerBot only to be confounded by jagged edges, corner lift, top layers that aren't solid, or any of a myriad of other problems that plague 3D printer enthusiasts, then here is the book to help you get past all that and recapture the joy of creative fabrication. The book also includes valuable tips for builders and those who want to modify the

  19. 3D-grafiikka ja pelimoottorit

    OpenAIRE

    Sillanpää, Otto

    2014-01-01

    Tässä opinnäytetyössä tutkitaan miten 3D-mallit saadaan sellaiseen muotoon, että ne olisivat käytettävissä eri pelimoottoreissa. Tutkimuksen tarkoituksena on selvittää, miten luodaan 3D-malleja pelimoottoreihin, sekä miten 3D-mallinnusohjelmat ja pelimoottorit eroavat toisistaan, kun käsitellään 3D-malleja. Tässä työssä pelimoottoreina toimivat Valven Source sekä Epic Gamesin Unreal Engine 3. 3D-mallinnusohjelmista käytössä olivat Autodeskin 3ds Max 2014 ja Blender Foundationin Blender 2.7...

  20. 6D Interpretation of 3D Gravity

    CERN Document Server

    Herfray, Yannick; Scarinci, Carlos

    2016-01-01

    We show that 3D gravity, in its pure connection formulation, admits a natural 6D interpretation. The 3D field equations for the connection are equivalent to 6D Hitchin equations for the Chern-Simons 3-form in the total space of the principal bundle over the 3-dimensional base. Turning this construction around one gets an explanation of why the pure connection formulation of 3D gravity exists. More generally, we interpret 3D gravity as the dimensional reduction of the 6D Hitchin theory. To this end, we show that any SU(2) invariant closed 3-form in the total space of the principal SU(2) bundle can be parametrised by a connection together with a 2-form field on the base. The dimensional reduction of the 6D Hitchin theory then gives rise to 3D gravity coupled to a topological 2-form field.

  1. Potts critical frontiers of inhomogeneous and asymmetric bow-tie lattices

    OpenAIRE

    Scullard, Christian R.; Jacobsen, Jesper Lykke

    2012-01-01

    We study the critical frontiers of the Potts model on two-dimensional bow-tie lattices with fully inhomogeneous coupling constants. Generally, for the Potts critical frontier to be found exactly, the underlying lattice must be a 3-uniform hypergraph. A more general class of lattices are the 4-uniform ones, with unit cells contained within four boundary vertices. We demonstrate that in some cases, such lattices can be decomposed into triangular cells, and solved using a modification of standar...

  2. The psychology of the 3D experience

    Science.gov (United States)

    Janicke, Sophie H.; Ellis, Andrew

    2013-03-01

    With 3D televisions expected to reach 50% home saturation as early as 2016, understanding the psychological mechanisms underlying the user response to 3D technology is critical for content providers, educators and academics. Unfortunately, research examining the effects of 3D technology has not kept pace with the technology's rapid adoption, resulting in large-scale use of a technology about which very little is actually known. Recognizing this need for new research, we conducted a series of studies measuring and comparing many of the variables and processes underlying both 2D and 3D media experiences. In our first study, we found narratives within primetime dramas had the power to shift viewer attitudes in both 2D and 3D settings. However, we found no difference in persuasive power between 2D and 3D content. We contend this lack of effect was the result of poor conversion quality and the unique demands of 3D production. In our second study, we found 3D technology significantly increased enjoyment when viewing sports content, yet offered no added enjoyment when viewing a movie trailer. The enhanced enjoyment of the sports content was shown to be the result of heightened emotional arousal and attention in the 3D condition. We believe the lack of effect found for the movie trailer may be genre-related. In our final study, we found 3D technology significantly enhanced enjoyment of two video games from different genres. The added enjoyment was found to be the result of an increased sense of presence.

  3. 3D Visualization Development of SIUE Campus

    Science.gov (United States)

    Nellutla, Shravya

    Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated.

  4. Multi-pulse time delay integration method for flexible 3D super-resolution range-gated imaging.

    Science.gov (United States)

    Xinwei, Wang; Youfu, Li; Yan, Zhou

    2015-03-23

    Constructing flexible regular-shaped range-intensity profiles by the convolution of illuminator laser pulse and sensor gate pulse is crucial for 3D super-resolution range-gated imaging. However, ns-scale rectangular-shaped laser pulse with tunable pulse width is difficult to be obtained, especially for pulsed solid-stated lasers. In this paper we propose a multi-pulse time delay integration (MPTDI) method to reshape range-intensity profiles (RIP) free from the above limitation of pulsed lasers. An equivalent laser pulse temporal shaping model is established to evaluate and optimize the MPTDI method. By using MPTDI, the RIP shape and depth of viewing can both be flexibly changed as desired. Here typical triangular and trapezoidal RIPs are established for 3D imaging under triangular and trapezoidal range-intensity correlation algorithms. In addition, a prototype experiment is demonstrated to prove the feasibility of MPTDI.

  5. Semi- and virtual 3D dosimetry in clinical practice

    DEFF Research Database (Denmark)

    Korreman, S. S.

    2013-01-01

    In this review, 3D dosimetry is divided in three categories; "true" 3D, semi-3D and virtual 3D. Virtual 3D involves the use of measurement arrays either before or after beam entry in the patient/phantom, whereas semi-3D involves use of measurement arrays in phantoms mimicking the patient. True 3D...

  6. 3D facial expression modeling for recognition

    Science.gov (United States)

    Lu, Xiaoguang; Jain, Anil K.; Dass, Sarat C.

    2005-03-01

    Current two-dimensional image based face recognition systems encounter difficulties with large variations in facial appearance due to the pose, illumination and expression changes. Utilizing 3D information of human faces is promising for handling the pose and lighting variations. While the 3D shape of a face does not change due to head pose (rigid) and lighting changes, it is not invariant to the non-rigid facial movement and evolution, such as expressions and aging effect. We propose a facial surface matching framework to match multiview facial scans to a 3D face model, where the (non-rigid) expression deformation is explicitly modeled for each subject, resulting in a person-specific deformation model. The thin plate spline (TPS) is applied to model the deformation based on the facial landmarks. The deformation is applied to the 3D neutral expression face model to synthesize the corresponding expression. Both the neutral and the synthesized 3D surface models are used to match a test scan. The surface registration and matching between a test scan and a 3D model are achieved by a modified Iterative Closest Point (ICP) algorithm. Preliminary experimental results demonstrate that the proposed expression modeling and recognition-by-synthesis schemes improve the 3D matching accuracy.

  7. Medical 3D Printing for the Radiologist.

    Science.gov (United States)

    Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J

    2015-01-01

    While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article.

  8. Digital relief generation from 3D models

    Science.gov (United States)

    Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian

    2016-09-01

    It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

  9. 3D Hilbert Space Filling Curves in 3D City Modeling for Faster Spatial Queries

    DEFF Research Database (Denmark)

    Ujang, Uznir; Antón Castro, Francesc/François; Azri, Suhaibah;

    2014-01-01

    objects. In this research, the authors propose an opponent data constellation technique of space-filling curves (3D Hilbert curves) for 3D city model data representation. Unlike previous methods, that try to project 3D or n-dimensional data down to 2D or 3D using Principal Component Analysis (PCA......) or Hilbert mappings, in this research, they extend the Hilbert space-filling curve to one higher dimension for 3D city model data implementations. The query performance was tested for single object, nearest neighbor and range search queries using a CityGML dataset of 1,000 building blocks and the results...... are presented in this paper. The advantages of implementing space-filling curves in 3D city modeling will improve data retrieval time by means of optimized 3D adjacency, nearest neighbor information and 3D indexing. The Hilbert mapping, which maps a sub-interval of the ([0,1]) interval to the corresponding...

  10. 3D Reconstruction Technique for Tomographic PIV

    Institute of Scientific and Technical Information of China (English)

    姜楠; 包全; 杨绍琼

    2015-01-01

    Tomographic particle image velocimetry(Tomo-PIV) is a state-of-the-art experimental technique based on a method of optical tomography to achieve the three-dimensional(3D) reconstruction for three-dimensional three-component(3D-3C) flow velocity measurements. 3D reconstruction for Tomo-PIV is carried out herein. Meanwhile, a 3D simplified tomographic reconstruction model reduced from a 3D volume light inten-sity field with 2D projection images into a 2D Tomo-slice plane with 1D projecting lines, i.e., simplifying this 3D reconstruction into a problem of 2D Tomo-slice plane reconstruction, is applied thereafter. Two kinds of the most well-known algebraic reconstruction techniques, algebraic reconstruction technique(ART) and multiple algebraic reconstruction technique(MART), are compared as well. The principles of the two reconstruction algorithms are discussed in detail, which has been performed by a series of simulation images, yielding the corresponding recon-struction images that show different features between the ART and MART algorithm, and then their advantages and disadvantages are discussed. Further discussions are made for the standard particle image reconstruction when the background noise of the pre-initial particle image has been removed. Results show that the particle image recon-struction has been greatly improved. The MART algorithm is much better than the ART. Furthermore, the computa-tional analyses of two parameters(the particle density and the number of cameras), are performed to study their effects on the reconstruction. Lastly, the 3D volume particle field is reconstructed by using the improved algorithm based on the simplified 3D tomographic reconstruction model, which proves that the algorithm simplification is feasible and it can be applied to the reconstruction of 3D volume particle field in a Tomo-PIV system.

  11. Extra Dimensions: 3D in PDF Documentation

    International Nuclear Information System (INIS)

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) and the ISO PRC file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. Until recently, Adobe's Acrobat software was also capable of incorporating 3D content into PDF files from a variety of 3D file formats, including proprietary CAD formats. However, this functionality is no longer available in Acrobat X, having been spun off to a separate company. Incorporating 3D content now requires the additional purchase of a separate plug-in. In this talk we present alternatives based on open source libraries which allow the programmatic creation of 3D content in PDF format. While not providing the same level of access to CAD files as the commercial software, it does provide physicists with an alternative path to incorporate 3D content into PDF files from such disparate applications as detector geometries from Geant4, 3D data sets, mathematical surfaces or tesselated volumes.

  12. Opening of triangular hole in triangular-shaped chemical vapor deposited hexagonal boron nitride crystal

    OpenAIRE

    Sharma, Subash; Kalita, Golap; Vishwakarma, Riteshkumar; Zulkifli, Zurita; Tanemura, Masaki

    2015-01-01

    In-plane heterostructure of monolayer hexagonal boron nitride (h-BN) and graphene is of great interest for its tunable bandgap and other unique properties. Here, we reveal a H2-induced etching process to introduce triangular hole in triangular-shaped chemical vapor deposited individual h-BN crystal. In this study, we synthesized regular triangular-shaped h-BN crystals with the sizes around 2-10 μm on Cu foil by chemical vapor deposition (CVD). The etching behavior of individual h-BN crystal w...

  13. Ultra-compact on-chip LED collimation optics by 3D femtosecond direct laser writing.

    Science.gov (United States)

    Thiele, Simon; Gissibl, Timo; Giessen, Harald; Herkommer, Alois M

    2016-07-01

    By using two-photon lithographic 3D printing, we demonstrate additive manufacturing of a dielectric concentrator directly on a LED chip. With a size of below 200 μm in diameter and length, light output is increased by a factor of 6.2 in collimation direction, while the emission half-angle is reduced by 50%. We measure excellent form fidelity and irradiance patterns close to simulation. Additionally, a more complex shape design is presented, which exhibits a nonconventional triangular illumination pattern. The introduced method features exceptional design freedoms which can be used to tailor high-quality miniature illumination optics for specific lighting tasks, for example, endoscopy. PMID:27367093

  14. Polarizablity of 2D and 3D conducting objects using method of moments

    CERN Document Server

    Shahpari, Morteza; Lewis, Andrew

    2014-01-01

    Fundamental antenna limits of the gain-bandwidth product are derived from polarizability calculations. This electrostatic technique has significant value in many antenna evaluations. Polarizability is not available in closed form for most antenna shapes and no commercial electromagnetic packages have this facility. Numerical computation of the polarizability for arbitrary conducting bodies was undertaken using an unstructured triangular mesh over the surface of 2D and 3D objects. Numerical results compare favourably with analytical solutions and can be implemented efficiently for large structures of arbitrary shape.

  15. An Improved Version of TOPAZ 3D

    CERN Document Server

    Krasnykh, Anatoly K

    2003-01-01

    An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.

  16. A high capacity 3D steganography algorithm.

    Science.gov (United States)

    Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee

    2009-01-01

    In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.

  17. 3D Printing the ATLAS' barrel toroid

    CERN Document Server

    Goncalves, Tiago Barreiro

    2016-01-01

    The present report summarizes my work as part of the Summer Student Programme 2016 in the CERN IR-ECO-TSP department (International Relations – Education, Communication & Outreach – Teacher and Student Programmes). Particularly, I worked closely with the S’Cool LAB team on a science education project. This project included the 3D designing, 3D printing, and assembling of a model of the ATLAS’ barrel toroid. A detailed description of the project' development is presented and a short manual on how to use 3D printing software and hardware is attached.

  18. Matching Feature Points in 3D World

    OpenAIRE

    Avdiu, Blerta

    2012-01-01

    This thesis work deals with the most actual topic in Computer Vision field which is scene understanding and this using matching of 3D feature point images. The objective is to make use of Saab’s latest breakthrough in extraction of 3D feature points, to identify the best alignment of at least two 3D feature point images. The thesis gives a theoretical overview of the latest algorithms used for feature detection, description and matching. The work continues with a brief description of the simu...

  19. Computer Modelling of 3D Geological Surface

    CERN Document Server

    Kodge, B G

    2011-01-01

    The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.

  20. General Concept of 3D SLAM

    OpenAIRE

    Zhang, Peter; Millos, Evangelous; Gu, Jason

    2009-01-01

    This chapter established an approach to solve the full 3D SLAM problem, applied to an underwater environment. First, a general approach to the 3D SLAM problem was presented, which included the models in 3D case, data association and estimation algorithm. For an underwater mobile robot, a new measurement system was designed for large area's globally-consistent SLAM: buoys for long-range estimation, and camera for short-range estimation and map building. Globally-consistent results could be obt...

  1. The reactor dynamics code DYN3D

    Energy Technology Data Exchange (ETDEWEB)

    Kliem, Soeren; Bilodid, Yuri; Fridman, Emil; Baier, Silvio; Grahn, Alexander; Gommlich, Andre; Nikitin, Evgeny; Rohde, Ulrich [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany)

    2016-05-15

    The article provides an overview on the code DYN3D which is a three-dimensional core model for steady-state, dynamic and depletion calculations in reactor cores with quadratic or hexagonal fuel assembly geometry being developed by the Helmholtz-Zentrum Dresden-Rossendorf for more than 20 years. The current paper gives an overview on the basic DYN3D models and the available code couplings. The verification and validation status is shortly outlined. The paper concludes with the current developments of the DYN3D code. For more detailed information the reader is referred to the publications cited in the corresponding chapters.

  2. 3D background aerodynamics using CFD

    DEFF Research Database (Denmark)

    Sørensen, Niels N.

    2002-01-01

    3D rotor computations for the Greek Geovilogiki (GEO) 44 meter rotor equipped with 19 meters blades are performed. The lift and drag polars are extracted at five spanvise locations r/R= (.37, .55, .71, .82, .93) based on identification of stagnationpoints between 2D and 3D computations. The inner...... most sections shows clear evidence of 3D radial pumping, with increased lift compared to 2D values. In contrast to earlier investigated airfoils a very limited impact on the drag values are observed....

  3. 3D tulostus - digitaalisesta mallista esineeksi

    OpenAIRE

    Muurinen, Kimmo

    2013-01-01

    Tässä opinnäytetyössä esitellään 3D tulostuksen tekniikka ja materiaaleja, suunnitellaan ja tuotetaan esimerkkikappaleen digitaalinen malli, sekä tulostetaan muovinen esine digi-taalisen mallin pohjalta. Työn tavoitteena on perehdyttää lukija prosessiin, jossa itse tuotettu digitaalinen malli tulostetaan käyttäen harrastajakäyttöön tarkoitettua edullista 3D tulostinta. Esimerkkikappaleen eri osien mallinnusprosessi näytetään kokonaisuudessaan ja kerro-taan perusteita 3D mallinnuksesta...

  4. Automatic balancing of 3D models

    DEFF Research Database (Denmark)

    Christiansen, Asger Nyman; Schmidt, Ryan; Bærentzen, Jakob Andreas

    2014-01-01

    3D printing technologies allow for more diverse shapes than are possible with molds and the cost of making just one single object is negligible compared to traditional production methods. However, not all shapes are suitable for 3D print. One of the remaining costs is therefore human time spent......, in these cases, we will apply a rotation of the object which only deforms the shape a little near the base. No user input is required but it is possible to specify manufacturing constraints related to specific 3D print technologies. Several models have successfully been balanced and printed using both polyjet...

  5. An Improved Version of TOPAZ 3D

    International Nuclear Information System (INIS)

    An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results

  6. FIT3D: Fitting optical spectra

    Science.gov (United States)

    Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.

    2016-09-01

    FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.

  7. FUN3D Manual: 12.5

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.5, including optional dependent packages. FUN3D is a suite of computational uid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables ecient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  8. FUN3D Manual: 13.0

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bill; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2016-01-01

    This manual describes the installation and execution of FUN3D version 13.0, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  9. FUN3D Manual: 12.9

    Science.gov (United States)

    Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2016-01-01

    This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  10. FUN3D Manual: 12.4

    Science.gov (United States)

    Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.

    2014-01-01

    This manual describes the installation and execution of FUN3D version 12.4, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixedelement unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.

  11. 3D grafika a hry

    OpenAIRE

    Vataščinová, Lenka

    2016-01-01

    In my bachelor thesis, I am going to introduce the topic of 3D graphics in the game environment. Firstly, I will provide a brief introduction of history of 3D graphics in general, but with the emphasis on history of game industry in particular. Next, I will present 3D graphics of RPG games in particular, and I will analyse the graphical side of digital work production. The main contribution of this thesis is provided in the practical part, which deals with creation of an environment for an an...

  12. 3-D Human Modeling and Animation

    CERN Document Server

    Ratner, Peter

    2012-01-01

    3-D Human Modeling and Animation Third Edition All the tools and techniques you need to bring human figures to 3-D life Thanks to today's remarkable technology, artists can create and animate realistic, three-dimensional human figures that were not possible just a few years ago. This easy-to-follow book guides you through all the necessary steps to adapt your own artistic skill in figure drawing, painting, and sculpture to this exciting digital canvas. 3-D Human Modeling and Animation, Third Edition starts you off with simple modeling, then prepares you for more advanced techniques for crea

  13. 3D face modeling, analysis and recognition

    CERN Document Server

    Daoudi, Mohamed; Veltkamp, Remco

    2013-01-01

    3D Face Modeling, Analysis and Recognition presents methodologies for analyzing shapes of facial surfaces, develops computational tools for analyzing 3D face data, and illustrates them using state-of-the-art applications. The methodologies chosen are based on efficient representations, metrics, comparisons, and classifications of features that are especially relevant in the context of 3D measurements of human faces. These frameworks have a long-term utility in face analysis, taking into account the anticipated improvements in data collection, data storage, processing speeds, and application s

  14. The reactor dynamics code DYN3D

    International Nuclear Information System (INIS)

    The article provides an overview on the code DYN3D which is a three-dimensional core model for steady-state, dynamic and depletion calculations in reactor cores with quadratic or hexagonal fuel assembly geometry being developed by the Helmholtz-Zentrum Dresden-Rossendorf for more than 20 years. The current paper gives an overview on the basic DYN3D models and the available code couplings. The verification and validation status is shortly outlined. The paper concludes with the current developments of the DYN3D code. For more detailed information the reader is referred to the publications cited in the corresponding chapters.

  15. 3D-hahmojen toteutus mobiilipeliin

    OpenAIRE

    Kemppainen, Matti

    2012-01-01

    Mobiilipelien suosio on kasvanut räjähdysmäisesti viime vuosina älypuhelinten kehittymisen myötä. Tässä opinnäytetyössä selvitetään kolmiulotteisen pelihahmon toteutusprosessi mobiilipeliin. Lisäksi pohditaan maksullisten ja ilmaisten ohjelmien eroja toteutuksessa. Pelihahmojen toteutus perustuu mobiilipeliprojektiin peliyrityksessä, jossa työskentelin graafikkona. Ohjelmien vertailussa on mukana 3D Studio Max, Blender 3D, Photoshop ja GIMP. Käytännön osuudessa käydään läpi 3D-pelihahmon...

  16. 3D-MR cholangio-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Ohkawa, Shinichi [Isehara Kyohdoh Hospital, Kanagawa (Japan); Hiramatsu, Kyoichi

    1995-04-01

    This report introduces a new 3D-MR cholangio-angiography technique using 3D Fast SE MR cholangiography and 3D phase contrast MR angiography for obstructive jaundice. In all eight cases, dilated biliary tracts as well as portal veins were clearly visualized in the same image. This new technique helped to determine the operability and surgical strategy for cases with obstructive jaundice. It also provided anatomical guidance for surgical procedures. This study suggests that this technique may replace the currently used modalities for obstructive jaundice. (author).

  17. Robust band gap and half-metallicity in graphene with triangular perforations

    Science.gov (United States)

    Gregersen, Søren Schou; Power, Stephen R.; Jauho, Antti-Pekka

    2016-06-01

    Ideal graphene antidot lattices are predicted to show promising band gap behavior (i.e., EG≃500 meV) under carefully specified conditions. However, for the structures studied so far this behavior is critically dependent on superlattice geometry and is not robust against experimentally realistic disorders. Here we study a rectangular array of triangular antidots with zigzag edge geometries and show that their band gap behavior qualitatively differs from the standard behavior which is exhibited, e.g., by rectangular arrays of armchair-edged triangles. In the spin unpolarized case, zigzag-edged antidots give rise to large band gaps compared to armchair-edged antidots, irrespective of the rules which govern the existence of gaps in armchair-edged antidot lattices. In addition the zigzag-edged antidots appear more robust than armchair-edged antidots in the presence of geometrical disorder. The inclusion of spin polarization within a mean-field Hubbard approach gives rise to a large overall magnetic moment at each antidot due to the sublattice imbalance imposed by the triangular geometry. Half-metallic behavior arises from the formation of spin-split dispersive states near the Fermi energy, reducing the band gaps compared to the unpolarized case. This behavior is also found to be robust in the presence of disorder. Our results highlight the possibilities of using triangular perforations in graphene to open electronic band gaps in systems with experimentally realistic levels of disorder, and furthermore, of exploiting the strong spin dependence of the system for spintronic applications.

  18. The 3D Object Mediator : Handling 3D Models on Internet

    NARCIS (Netherlands)

    Kok, A.J.F.; Lawick van Pabst, J. van; Afsarmanesh, H.

    1997-01-01

    The 3D Object MEdiator (3DOME 3) offers two services for handling 3D models: a modelshop and a renderfarm. These services can be consulted through the Internet. The modelshop meets the demands for brokerage of geometric descriptions of 3D models. People who create geometric models of objects can sup

  19. XML3D and Xflow: combining declarative 3D for the Web with generic data flows.

    Science.gov (United States)

    Klein, Felix; Sons, Kristian; Rubinstein, Dmitri; Slusallek, Philipp

    2013-01-01

    Researchers have combined XML3D, which provides declarative, interactive 3D scene descriptions based on HTML5, with Xflow, a language for declarative, high-performance data processing. The result lets Web developers combine a 3D scene graph with data flows for dynamic meshes, animations, image processing, and postprocessing. PMID:24808080

  20. 3D presentatie van geluid in de cockpit [3D sound presentation in the cockpit

    NARCIS (Netherlands)

    Bronkhorst, A.W.

    2003-01-01

    A.W. Bronkhorst, 3D-presentatie van geluid in de cockpit 1 Using virtual acoustics, sound can be presented from virtual sources located in the 3D space around the listener. This 3D sound has interesting applications in the cockpit. Sounds can be used to convey directional information, and interferen

  1. Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing

    Science.gov (United States)

    Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.

    2016-01-01

    Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…

  2. Full Core 3-D Simulation of a Partial MOX LWR Core

    Energy Technology Data Exchange (ETDEWEB)

    S. Bays; W. Skerjanc; M. Pope

    2009-05-01

    A comparative analysis and comparison of results obtained between 2-D lattice calculations and 3-D full core nodal calculations, in the frame of MOX fuel design, was conducted. This study revealed a set of advantages and disadvantages, with respect to each method, which can be used to guide the level of accuracy desired for future fuel and fuel cycle calculations. For the purpose of isotopic generation for fuel cycle analyses, the approach of using a 2-D lattice code (i.e., fuel assembly in infinite lattice) gave reasonable predictions of uranium and plutonium isotope concentrations at the predicted 3-D core simulation batch average discharge burnup. However, it was found that the 2-D lattice calculation can under-predict the power of pins located along a shared edge between MOX and UO2 by as much as 20%. In this analysis, this error did not occur in the peak pin. However, this was a coincidence and does not rule out the possibility that the peak pin could occur in a lattice position with high calculation uncertainty in future un-optimized studies. Another important consideration in realistic fuel design is the prediction of the peak axial burnup and neutron fluence. The use of 3-D core simulation gave peak burnup conditions, at the pellet level, to be approximately 1.4 times greater than what can be predicted using back-of-the-envelope assumptions of average specific power and irradiation time.

  3. Solutions to the Triangular Bicycle Flags Problem

    Science.gov (United States)

    Hartweg, Kim

    2005-01-01

    Students in a fifth-grade general education class and a second-grade gifted class participated in the Triangular Bicycle Flags problem. The results indicated that providing students with geometric experiences at the correct van Hiele level is necessary for helping students move from one level of understanding to the next.

  4. Basic Employability Skills: A Triangular Design Approach

    Science.gov (United States)

    Rosenberg, Stuart; Heimler, Ronald; Morote, Elsa-Sofia

    2012-01-01

    Purpose: This paper seeks to examine the basic employability skills needed for job performance, the reception of these skills in college, and the need for additional training in these skills after graduation. Design/methodology/approach: The research was based on a triangular design approach, in which the attitudes of three distinct groups--recent…

  5. Lightning fast animation in Element 3D

    CERN Document Server

    Audronis, Ty

    2014-01-01

    An easy-to-follow and all-inclusive guide, in which the underlying principles of 3D animation as well as their importance are explained in detail. The lessons are designed to teach you how to think of 3D animation in such a way that you can troubleshoot any problem, or animate any scene that comes your way.If you are a Digital Artist, Animation Artist, or a Game Programmer and you want to become an expert in Element 3D, this is the book for you. Although there are a lot of basics for beginners in this book, it includes some advanced techniques for both animating in Element 3D, and overcoming i

  6. Eyes on the Earth 3D

    Science.gov (United States)

    Kulikov, anton I.; Doronila, Paul R.; Nguyen, Viet T.; Jackson, Randal K.; Greene, William M.; Hussey, Kevin J.; Garcia, Christopher M.; Lopez, Christian A.

    2013-01-01

    Eyes on the Earth 3D software gives scientists, and the general public, a realtime, 3D interactive means of accurately viewing the real-time locations, speed, and values of recently collected data from several of NASA's Earth Observing Satellites using a standard Web browser (climate.nasa.gov/eyes). Anyone with Web access can use this software to see where the NASA fleet of these satellites is now, or where they will be up to a year in the future. The software also displays several Earth Science Data sets that have been collected on a daily basis. This application uses a third-party, 3D, realtime, interactive game engine called Unity 3D to visualize the satellites and is accessible from a Web browser.

  7. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  8. 3D-FPA Hybridization Improvements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  9. Copper Electrodeposition for 3D Integration

    CERN Document Server

    Beica, Rozalia; Ritzdorf, Tom

    2008-01-01

    Two dimensional (2D) integration has been the traditional approach for IC integration. Due to increasing demands for providing electronic devices with superior performance and functionality in more efficient and compact packages, has driven the semiconductor industry to develop more advanced packaging technologies. Three-dimensional (3D) approaches address both miniaturization and integration required for advanced and portable electronic products. Vertical integration proved to be essential in achieving a greater integration flexibility of disparate technologies, reason for which a general trend of transition from 2D to 3D integration is currently being observed in the industry. 3D chip integration using through silicon via (TSV) copper is considered one of the most advanced technologies among all different types of 3D packaging technologies. Copper electrodeposition is one of technologies that enable the formation of TSV structures. Because of its well-known application for copper damascene, it was believed ...

  10. 3D Biomaterial Microarrays for Regenerative Medicine

    DEFF Research Database (Denmark)

    Gaharwar, Akhilesh K.; Arpanaei, Ayyoob; Andresen, Thomas Lars;

    2015-01-01

    Three dimensional (3D) biomaterial microarrays hold enormous promise for regenerative medicine because of their ability to accelerate the design and fabrication of biomimetic materials. Such tissue-like biomaterials can provide an appropriate microenvironment for stimulating and controlling stem...

  11. 3DSEM: A 3D microscopy dataset.

    Science.gov (United States)

    Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun

    2016-03-01

    The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561

  12. 3DSEM: A 3D microscopy dataset

    Directory of Open Access Journals (Sweden)

    Ahmad P. Tafti

    2016-03-01

    Full Text Available The Scanning Electron Microscope (SEM as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples.

  13. 3D Visualization of Recent Sumatra Earthquake

    Science.gov (United States)

    Nayak, Atul; Kilb, Debi

    2005-04-01

    Scientists and visualization experts at the Scripps Institution of Oceanography have created an interactive three-dimensional visualization of the 28 March 2005 magnitude 8.7 earthquake in Sumatra. The visualization shows the earthquake's hypocenter and aftershocks recorded until 29 March 2005, and compares it with the location of the 26 December 2004 magnitude 9 event and the consequent seismicity in that region. The 3D visualization was created using the Fledermaus software developed by Interactive Visualization Systems (http://www.ivs.unb.ca/) and stored as a ``scene'' file. To view this visualization, viewers need to download and install the free viewer program iView3D (http://www.ivs3d.com/products/iview3d).

  14. 3D VISUALIZATION FOR VIRTUAL MUSEUM DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    M. Skamantzari

    2016-06-01

    Full Text Available The interest in the development of virtual museums is nowadays rising rapidly. During the last decades there have been numerous efforts concerning the 3D digitization of cultural heritage and the development of virtual museums, digital libraries and serious games. The realistic result has always been the main concern and a real challenge when it comes to 3D modelling of monuments, artifacts and especially sculptures. This paper implements, investigates and evaluates the results of the photogrammetric methods and 3D surveys that were used for the development of a virtual museum. Moreover, the decisions, the actions, the methodology and the main elements that this kind of application should include and take into consideration are described and analysed. It is believed that the outcomes of this application will be useful to researchers who are planning to develop and further improve the attempts made on virtual museums and mass production of 3D models.

  15. Cubical Cohomology Ring of 3D Photographs

    CERN Document Server

    Gonzalez-Diaz, Rocio; Medrano, Belen; 10.1002/ima.20271

    2011-01-01

    Cohomology and cohomology ring of three-dimensional (3D) objects are topological invariants that characterize holes and their relations. Cohomology ring has been traditionally computed on simplicial complexes. Nevertheless, cubical complexes deal directly with the voxels in 3D images, no additional triangulation is necessary, facilitating efficient algorithms for the computation of topological invariants in the image context. In this paper, we present formulas to directly compute the cohomology ring of 3D cubical complexes without making use of any additional triangulation. Starting from a cubical complex $Q$ that represents a 3D binary-valued digital picture whose foreground has one connected component, we compute first the cohomological information on the boundary of the object, $\\partial Q$ by an incremental technique; then, using a face reduction algorithm, we compute it on the whole object; finally, applying the mentioned formulas, the cohomology ring is computed from such information.

  16. Networked 3D Virtual Museum System

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Virtual heritage has become increasingly important in the conservation, preservation, and interpretation of our cultural and natural history. Moreover, rapid advances in digital technologies in recent years offer virtual heritage new direction. This paper introduces our approach toward a networked 3D virtual museum system, especially, how to model, manage, present virtual heritages and furthermore how to use computer network for the share of virtual heritage in the networked virtual environment. This paper first addresses a 3D acquisition and processing technique for virtual heritage modeling and shows some illustrative examples. Then, this paper describes a management of virtual heritage assets that are composed by various rich media. This paper introduces our schemes to present the virtual heritages, which include 3D virtual heritage browser system, CAVE system, and immersive VR theater. Finally, this paper presents the new direction of networked 3D virtual museum of which main idea is remote guide of the virtual heritage using the mixed reality technique.

  17. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...... shutter is controlled in steps of 100 ps. Camera delay is controlled in steps of 100 ps. Each laser pulse triggers the camera delay and shutter. A 3-D image is constructed from a sequence of 50-100 2-D reflectivity images, where each frame integrates about 700 laser pulses on the CCD. In 50 Hz video mode...... we record a 2-D sequence in a second and process a 3-D image in few seconds. We compare 3-D images with a system performance model....

  18. Nonlaser-based 3D surface imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  19. Tvorba 3D modelů

    OpenAIRE

    Musálek, Martin

    2014-01-01

    Práce řeší 3D rekonstrukci objektu pomocí metody nasvícení vzorem. Projektor nasvěcuje měřený objekt definovaným vzorem a dvojice kamer z něj snímá body. Podstavec s objektem se otáčí, a během více měření je objekt sejmut z více úhlů. Body jsou identifikovány z naměřených snímků, transformovány na 3D pomocí stereovidění, spojeny do 3D modelu a zobrazeny. Thesis solves 3D reconstruction of an object by method of lighting by pattern. A projector lights the measured object by defined pattern ...

  20. 3D Maps Representation Using GNG

    Directory of Open Access Journals (Sweden)

    Vicente Morell

    2014-01-01

    Full Text Available Current RGB-D sensors provide a big amount of valuable information for mobile robotics tasks like 3D map reconstruction, but the storage and processing of the incremental data provided by the different sensors through time quickly become unmanageable. In this work, we focus on 3D maps representation and propose the use of the Growing Neural Gas (GNG network as a model to represent 3D input data. GNG method is able to represent the input data with a desired amount of neurons or resolution while preserving the topology of the input space. Experiments show how GNG method yields a better input space adaptation than other state-of-the-art 3D map representation methods.

  1. 3D-printed bioanalytical devices

    Science.gov (United States)

    Bishop, Gregory W.; Satterwhite-Warden, Jennifer E.; Kadimisetty, Karteek; Rusling, James F.

    2016-07-01

    While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.

  2. Advanced 3D Object Identification System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optra will build an Advanced 3D Object Identification System utilizing three or more high resolution imagers spaced around a launch platform. Data from each imager...

  3. Measuring Visual Closeness of 3-D Models

    KAUST Repository

    Morales, Jose A.

    2012-09-01

    Measuring visual closeness of 3-D models is an important issue for different problems and there is still no standardized metric or algorithm to do it. The normal of a surface plays a vital role in the shading of a 3-D object. Motivated by this, we developed two applications to measure visualcloseness, introducing normal difference as a parameter in a weighted metric in Metro’s sampling approach to obtain the maximum and mean distance between 3-D models using 3-D and 6-D correspondence search structures. A visual closeness metric should provide accurate information on what the human observers would perceive as visually close objects. We performed a validation study with a group of people to evaluate the correlation of our metrics with subjective perception. The results were positive since the metrics predicted the subjective rankings more accurately than the Hausdorff distance.

  4. Transportstromen verschuiven door toepassing 3-D

    NARCIS (Netherlands)

    Janssen, G.R.

    2014-01-01

    3-D printing is aan een gestage opmars bezig.ln een paar jaar tijd is er een miljardenmarkt ontstaan die exponentieel groeit. TNO deed onderzoek naar de impact van deze ontwikkelingen op supply chains.

  5. Pentingnya Pengetahuan Anatomi untuk 3D Artist

    Directory of Open Access Journals (Sweden)

    Anton Sugito Kurniawan

    2011-03-01

    Full Text Available No matter how far the current technological advances, anatomical knowledge will still be needed as a basis for making a good character design. Understanding anatomy will help us in the placement of the articulation of muscles and joints, thus more realistic modeling of 3d characters will be achieved in the form and movement. As a 3d character artist, anatomy should be able to inform in every aspect of our work. Each 3D/CG (Computer Graphics-artist needs to know how to use software applications, but what differentiates a 3d artist with a computer operator is an artistic vision and understanding of the basic shape of the human body. Artistic vision could not easily be taught, but a CG-artist may study it on their own from which so many reference sources may help understand and deepen their knowledge of anatomy.

  6. Embedding 3D into multipurpose cadastre

    OpenAIRE

    A. A. Rahman; T. C. Hua; P. J. M. Van Oosterom

    2011-01-01

    There is no doubt that the cadastral map provides a useful entrance to information in a land parcel based information system. However, such information system could be made more meaningful and useful if it can be extended for multiple usages with multi data layers, and in three-dimensions (3D). Currently, many national mapping and cadastral agencies (NMCAs) and users deal with complex situations, and we believe that 3D could enhance the understanding of the situations better. This paper descr...

  7. Luovasta konseptisuunnittelusta 3D-mainoselokuvaan

    OpenAIRE

    Salo, Suvi

    2015-01-01

    Insinöörityön tavoite oli luoda 3D-mainoselokuva myynnin tueksi ja nostaa esiin IT-alan yrityksen ja sen yksikön tuottamien palveluiden laajuutta ja yrityksen tapaa tuottaa tulostuspalvelua. Toteutettu mainoselokuva on tarkoitettu julkaistavaksi verkossa yrityksen omalla Youtube-kanavalla ja verkkosivuilla. 3D-mainoselokuvan suunnittelussa käytettiin luovan konseptisuunnittelun keinoja jalostaa tarina kohderyhmälähtöiseksi. Aluksi selvitettiin asiakasrajapinnan haastattelujen avulla kohde...

  8. 3D printing: technology and processing

    OpenAIRE

    Kurinov, Ilya

    2016-01-01

    The objective of the research was to improve the process of 3D printing on the laboratory machine. In the study processes of designing, printing and post-print-ing treatment were improved. The study was commissioned by Mikko Ruotsalainen, head of the laboratory. The data was collected during the test work. All the basic information about 3D printing was taken from the Internet or library. As the results of the project higher model accuracy, solutions for post-printing treatment, printin...

  9. The Idaho Virtualization Laboratory 3D Pipeline

    Directory of Open Access Journals (Sweden)

    Nicholas A. Holmer

    2014-05-01

    Full Text Available Three dimensional (3D virtualization and visualization is an important component of industry, art, museum curation and cultural heritage, yet the step by step process of 3D virtualization has been little discussed. Here we review the Idaho Virtualization Laboratory’s (IVL process of virtualizing a cultural heritage item (artifact from start to finish. Each step is thoroughly explained and illustrated including how the object and its metadata are digitally preserved and ultimately distributed to the world.

  10. 3D Printing for Tissue Engineering

    OpenAIRE

    Richards, Dylan Jack; Tan, Yu; Jia, Jia; Yao, Hai; Mei, Ying

    2013-01-01

    Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host ...

  11. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  12. Assembling Fibonacci anyons from a Z3 parafermion lattice model

    Science.gov (United States)

    Stoudenmire, E. M.; Clarke, David J.; Mong, Roger S. K.; Alicea, Jason

    2015-06-01

    Recent concrete proposals suggest it is possible to engineer a two-dimensional bulk phase supporting non-Abelian Fibonacci anyons out of Abelian fractional quantum Hall systems. The low-energy degrees of freedom of such setups can be modeled as Z3 parafermions "hopping" on a two-dimensional lattice. We use the density matrix renormalization group to study a model of this type interpolating between the decoupled-chain, triangular-lattice, and square-lattice limits. The results show clear evidence of the Fibonacci phase over a wide region of the phase diagram, most notably including the isotropic triangular-lattice point. We also study the broader phase diagram of this model and show that elsewhere it supports an Abelian state with semionic excitations.

  13. LandSIM3D: modellazione in real time 3D di dati geografici

    OpenAIRE

    Lambo Srl Lambo Srl

    2009-01-01

    LandSIM3D: realtime 3D modelling of geographic dataLandSIM3D allows to model in 3D an existing landscape in a few hours only and geo-referenced offering great landscape analysis and understanding tools. 3D projects can then be inserted into the existing landscape with ease and precision. The project alternatives and impact can then be visualized and studied into their immediate environmental. The complex evolution of the landscape in the future can also be simulated and the landscape model ca...

  14. ASSESSING 3D PHOTOGRAMMETRY TECHNIQUES IN CRANIOMETRICS

    Directory of Open Access Journals (Sweden)

    M. C. Moshobane

    2016-06-01

    Full Text Available Morphometrics (the measurement of morphological features has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc® three-dimensional (3D modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis and Antarctic fur seal (Arctocephalus gazella skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model’s accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.

  15. Assessing 3d Photogrammetry Techniques in Craniometrics

    Science.gov (United States)

    Moshobane, M. C.; de Bruyn, P. J. N.; Bester, M. N.

    2016-06-01

    Morphometrics (the measurement of morphological features) has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc®) three-dimensional (3D) modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis) and Antarctic fur seal (Arctocephalus gazella) skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model's accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.

  16. Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.

    Science.gov (United States)

    Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L

    2015-06-01

    Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care.

  17. RAG-3D: a search tool for RNA 3D substructures.

    Science.gov (United States)

    Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar

    2015-10-30

    To address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D-a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool-designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding. PMID:26304547

  18. 3D-mallien muokkaus 3D-tulostamista varten CAD-ohjelmilla

    OpenAIRE

    Lehtimäki, Jarmo

    2013-01-01

    Insinöörityössäni käsitellään 3D-mallien tulostamista ja erityisesti 3D-mallien mallintamista niin, että kappaleiden valmistaminen 3D-tulostimella onnistuisi mahdollisimman hyvin. Työ tehtiin Prohoc Oy:lle, joka sijaitsee Vaasassa. 3D-tulostuspalveluun tuli jatkuvasti 3D-malleja, joiden tulostuksessa oli ongelmia. Työssäni tutkin näiden ongelmien syntyä ja tein ohjeita eri 3D-mallinnusohjelmille, joiden tarkoituksena on auttaa tekemään helpommin tulostettavia 3D-malleja. Työhön kuului myös et...

  19. Indications of c-axis Charge Transport in Hole Doped Triangular Antiferromagnets

    Institute of Scientific and Technical Information of China (English)

    LIANG Ying; LIU Bin; FENG Shi-Ping

    2004-01-01

    The c-axis charge transport of the hole doped triangular antiferromagnet is investigated within the tJ model by considering the incoherent interlayer hopping.It is shown that the c-axis charge transport of the hole doped triangular antiferromagnet is essentially determined by the scattering from the in-plane fluctuation.The c-axis conductivity spectrum shows a lov-energy peak and the unusual high-energy broad band,while the c-axis resistivity is characterized by a crossover from the high temperature metallic-like behavior to the Iow temperature insulating-like behavior,which is qualitatively consistent with those of the hole doped square lattice antiferromagnet.

  20. Robust band gap and half-metallicity in graphene with triangular perforations

    DEFF Research Database (Denmark)

    Gregersen, Søren Schou; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    Ideal graphene antidot lattices are predicted to show promising band gap behavior (i.e., EG ≅ 500 meV) under carefully specified conditions. However, for the structures studied so far this behavior is critically dependent on superlattice geometry and is not robust against experimentally realistic...... disorders. Here we study a rectangular array of triangular antidots with zigzag edge geometries and show that their band gap behavior qualitatively differs from the standard behavior which is exhibited, e.g., by rectangular arrays of armchair-edged triangles. In the spin unpolarized case, zigzag......, reducing the band gaps compared to the unpolarized case. This behavior is also found to be robust in the presence of disorder. Our results highlight the possibilities of using triangular perforations in graphene to open electronic band gaps in systems with experimentally realistic levels of disorder...

  1. Thin slice three dimentional (3D reconstruction versus CT 3D reconstruction of human breast cancer

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2013-01-01

    Full Text Available Background & objectives: With improvement in the early diagnosis of breast cancer, breast conserving therapy (BCT is being increasingly used. Precise preoperative evaluation of the incision margin is, therefore, very important. Utilizing three dimentional (3D images in a preoperative evaluation for breast conserving surgery has considerable significance, but the currently 3D CT scan reconstruction commonly used has problems in accurately displaying breast cancer. Thin slice 3D reconstruction is also widely used now to delineate organs and tissues of breast cancers. This study was aimed to compare 3D CT with thin slice 3D reconstruction in breast cancer patients to find a better technique for accurate evaluation of breast cancer. Methods: A total of 16-slice spiral CT scans and 3D reconstructions were performed on 15 breast cancer patients. All patients had been treated with modified radical mastectomy; 2D and 3D images of breast and tumours were obtained. The specimens were fixed and sliced at 2 mm thickness to obtain serial thin slice images, and reconstructed using 3D DOCTOR software to gain 3D images. Results: Compared with 2D CT images, thin slice images showed more clearly the morphological characteristics of tumour, breast tissues and the margins of different tissues in each slice. After 3D reconstruction, the tumour shapes obtained by the two reconstruction methods were basically the same, but the thin slice 3D reconstruction showed the tumour margins more clearly. Interpretation & conclusions: Compared with 3D CT reconstruction, thin slice 3D reconstruction of breast tumour gave clearer images, which could provide guidance for the observation and application of CT 3D reconstructed images and contribute to the accurate evaluation of tumours using CT imaging technology.

  2. 3D-PRINTING OF BUILD OBJECTS

    Directory of Open Access Journals (Sweden)

    SAVYTSKYI M. V.

    2016-03-01

    Full Text Available Raising of problem. Today, in all spheres of our life we can constate the permanent search for new, modern methods and technologies that meet the principles of sustainable development. New approaches need to be, on the one hand more effective in terms of conservation of exhaustible resources of our planet, have minimal impact on the environment and on the other hand to ensure a higher quality of the final product. Construction is not exception. One of the new promising technology is the technology of 3D -printing of individual structures and buildings in general. 3Dprinting - is the process of real object recreating on the model of 3D. Unlike conventional printer which prints information on a sheet of paper, 3D-printer allows you to display three-dimensional information, i.e. creates certain physical objects. Currently, 3D-printer finds its application in many areas of production: machine building elements, a variety of layouts, interior elements, various items. But due to the fact that this technology is fairly new, it requires the creation of detailed and accurate technologies, efficient equipment and materials, and development of common vocabulary and regulatory framework in this field. Research Aim. The analysis of existing methods of creating physical objects using 3D-printing and the improvement of technology and equipment for the printing of buildings and structures. Conclusion. 3D-printers building is a new generation of equipment for the construction of buildings, structures, and structural elements. A variety of building printing technics opens up wide range of opportunities in the construction industry. At this stage, printers design allows to create low-rise buildings of different configurations with different mortars. The scientific novelty of this work is to develop proposals to improve the thermal insulation properties of constructed 3D-printing objects and technological equipment. The list of key terms and notions of construction

  3. Eutectic point in a simple lattice gas model

    OpenAIRE

    M. Sandhoff; Pfnuer, H.; Everts, H. U.

    1993-01-01

    We investigate the phase diagram and the critical properties of the adsorbate system sulphur/ruthenium(0001) in the coverage region $\\frac{1}{4} < \\Theta < \\frac{1}{3}$ by means of Monte-Carlo simulations of a simple lattice gas model on a triangular lattice. The model contains only repulsive nearest and next-nearest neighbor interactions. Combining results obtained by using both Glauber and Kawasaki kinetics in the simulations we identify two tricritical points, three coexistence regions and...

  4. Topological spin models in Rydberg lattices

    CERN Document Server

    Kiffner, Martin; Jaksch, Dieter

    2016-01-01

    We show that resonant dipole-dipole interactions between Rydberg atoms in a triangular lattice can give rise to artificial magnetic fields for spin excitations. We consider the coherent dipole-dipole coupling between $np$ and $ns$ Rydberg states and derive an effective spin-1/2 Hamiltonian for the $np$ excitations. By breaking time-reversal symmetry via external fields we engineer complex hopping amplitudes for transitions between two rectangular sub-lattices. The phase of these hopping amplitudes depends on the direction of the hop. This gives rise to a staggered, artificial magnetic field which induces non-trivial topological effects. We calculate the single-particle band structure and investigate its Chern numbers as a function of the lattice parameters and the detuning between the two sub-lattices. We identify extended parameter regimes where the Chern number of the lowest band is $C=1$ or $C=2$.

  5. Photonic band structures of two-dimensional photonic crystals with deformed lattices

    Institute of Scientific and Technical Information of China (English)

    Cai Xiang-Hua; Zheng Wan-Hua; Ma Xiao-Tao; Ren Gang; Xia Jian-Bai

    2005-01-01

    Using the plane-wave expansion method, we have calculated and analysed the changes of photonic band structures arising from two kinds of deformed lattices, including the stretching and shrinking of lattices. The square lattice with square air holes and the triangular lattice with circular air holes are both studied. Calculated results show that the change of lattice size in some special ranges can enlarge the band gap, which depends strongly on the filling factor of air holes in photonic crystals; and besides, the asymmetric band edges will appear with the broken symmetry of lattices.

  6. PLOT3D Export Tool for Tecplot

    Science.gov (United States)

    Alter, Stephen

    2010-01-01

    The PLOT3D export tool for Tecplot solves the problem of modified data being impossible to output for use by another computational science solver. The PLOT3D Exporter add-on enables the use of the most commonly available visualization tools to engineers for output of a standard format. The exportation of PLOT3D data from Tecplot has far reaching effects because it allows for grid and solution manipulation within a graphical user interface (GUI) that is easily customized with macro language-based and user-developed GUIs. The add-on also enables the use of Tecplot as an interpolation tool for solution conversion between different grids of different types. This one add-on enhances the functionality of Tecplot so significantly, it offers the ability to incorporate Tecplot into a general suite of tools for computational science applications as a 3D graphics engine for visualization of all data. Within the PLOT3D Export Add-on are several functions that enhance the operations and effectiveness of the add-on. Unlike Tecplot output functions, the PLOT3D Export Add-on enables the use of the zone selection dialog in Tecplot to choose which zones are to be written by offering three distinct options - output of active, inactive, or all zones (grid blocks). As the user modifies the zones to output with the zone selection dialog, the zones to be written are similarly updated. This enables the use of Tecplot to create multiple configurations of a geometry being analyzed. For example, if an aircraft is loaded with multiple deflections of flaps, by activating and deactivating different zones for a specific flap setting, new specific configurations of that aircraft can be easily generated by only writing out specific zones. Thus, if ten flap settings are loaded into Tecplot, the PLOT3D Export software can output ten different configurations, one for each flap setting.

  7. Quasi-hexagonal vortex-pinning lattice using anodized aluminum oxide nanotemplates

    DEFF Research Database (Denmark)

    Hallet, X.; Mátéfi-Tempfli, M.; Michotte, S.;

    2009-01-01

    The bottom barrier layer of well-ordered nanoporous alumina membranes reveals a previously unexploited nanostructured template surface consisting of a triangular lattice of hemispherical nanoscale bumps. Quasi-hexagonal vortex-pinning lattice arrays are created in superconducting Nb films deposit...

  8. Multirresolución adaptativa de mallas triangulares basado en criterios de textura

    Directory of Open Access Journals (Sweden)

    Alexánder Ceballos

    2007-01-01

    Full Text Available Los modelos 3D están generalmente compuestos por miles de polígonos. En ocasiones estas representaciones pueden obtenerse con la misma calidad visual pero con un menor número de polígonos. En este artículo se propone un método para reducir el tamaño de imágenes 3D texturadas basadas en mallas triangulares, conservando la calidad visual del modelo. Se introduce un criterio de textura que controla el proceso de decimación triangular. Para eliminar puntos sin necesidad de realizar una nueva triangulación, sobre la nube de puntos se usa un algoritmo poligonal de decimación. Para definir cuáles puntos deben ser removidos, se usa un filtro de Sobel 2D sobre la textura correspondiente. Se muestra que se puede usar el algoritmo para reducir los tiempos de carga, de renderización, de transferencia y de almacenamiento de una imagen 3D texturada

  9. A microfluidic device for 2D to 3D and 3D to 3D cell navigation

    International Nuclear Information System (INIS)

    Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies. (paper)

  10. A microfluidic device for 2D to 3D and 3D to 3D cell navigation

    Science.gov (United States)

    Shamloo, Amir; Amirifar, Leyla

    2016-01-01

    Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.

  11. Superradiance Lattice

    CERN Document Server

    Wang, Da-Wei; Zhu, Shi-Yao; Scully, Marlan O

    2014-01-01

    We show that the timed Dicke states of a collection of three-level atoms can form a tight-binding lattice in the momentum space. This lattice, coined the superradiance lattice (SL), can be constructed based on an electromagnetically induced transparency (EIT) system. For a one-dimensional SL, we need the coupling field of the EIT system to be a standing wave. The detuning between the two components of the standing wave introduces an effective electric field. The quantum behaviours of electrons in lattices, such as Bloch oscillations, Wannier-Stark ladders, Bloch band collapsing and dynamic localization can be observed in the SL. The SL can be extended to two, three and even higher dimensions where no analogous real space lattices exist and new physics are waiting to be explored.

  12. An algorithm for studying rigidity in disordered 3D networks

    Science.gov (United States)

    Chubynsky, M. V.; Thorpe, M. F.

    2004-03-01

    Some physical systems, such as covalent glasses and proteins, can be modeled as elastic networks, by dividing the interactions between particles into strong and weak, representing the former as constraints and neglecting the latter. For low enough connectivities, motions maintaining the constraints and thus having zero energy cost are possible. The goal of rigidity analysis is finding the number of such zero energy modes, the rigid clusters and flexible joints between them, as well as stressed bonds. For a certain class of networks there is a very fast graph-theoretical algorithm (the Pebble Game) for doing this analysis, but for more general networks, there are known counterexamples. While generalizing the Pebble Game is the ultimate goal, we propose a slower algorithm capable of doing all the same analyses as the Pebble Game but applicable to any networks. We discuss the applications of this algorithm to specific examples of 3D networks, such as diluted central force lattices, colloidal glasses and proteins.

  13. Validation of 3D simulations of reverse osmosis membrane biofouling.

    Science.gov (United States)

    Pintelon, Thomas R R; Creber, Sarah A; von der Schulenburg, Daniel A Graf; Johns, Michael L

    2010-07-01

    The increasing demand for drinking water and its stricter quality requirements have resulted in an exponentially expanding industry of membrane filtration processes. Currently, reverse osmosis (RO) is the most common method of desalination, able to produce water that is virtually free of pollutants and pathogenic micro-organisms. Biofouling of these devices however is a significant limitation. Here we present a 3D simulation of RO membrane biofouling based on a lattice Boltzmann (LB) platform that we subsequently favorably compare with experimental data. This data consists of temporally (and spatially) resolved velocity measurements acquired for a RO membrane using magnetic resonance techniques. The effect of biofilm cohesive strength on system pressure drop is then explored; weaker biomass is observed to have a reduced impact on pressure drop (per unit biomass accumulated).

  14. The importance of 3D dosimetry

    International Nuclear Information System (INIS)

    Radiation therapy has been getting progressively more complex for the past 20 years. Early radiation therapy techniques needed only basic dosimetry equipment; motorized water phantoms, ionization chambers, and basic radiographic film techniques. As intensity modulated radiation therapy and image guided therapy came into widespread practice, medical physicists were challenged with developing effective and efficient dose measurement techniques. The complex 3-dimensional (3D) nature of the dose distributions that were being delivered demanded the development of more quantitative and more thorough methods for dose measurement. The quality assurance vendors developed a wide array of multidetector arrays that have been enormously useful for measuring and characterizing dose distributions, and these have been made especially useful with the advent of 3D dose calculation systems based on the array measurements, as well as measurements made using film and portal imagers. Other vendors have been providing 3D calculations based on data from the linear accelerator or the record and verify system, providing thorough evaluation of the dose but lacking quality assurance (QA) of the dose delivery process, including machine calibration. The current state of 3D dosimetry is one of a state of flux. The vendors and professional associations are trying to determine the optimal balance between thorough QA, labor efficiency, and quantitation. This balance will take some time to reach, but a necessary component will be the 3D measurement and independent calculation of delivered radiation therapy dose distributions

  15. Magnetic Properties of 3D Printed Toroids

    Science.gov (United States)

    Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team

    Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.

  16. 3D analysis methods - Study and seminar

    International Nuclear Information System (INIS)

    The first part of the report results from a study that was performed as a Nordic co-operation activity with active participation from Studsvik Scandpower and Westinghouse Atom in Sweden, and VTT in Finland. The purpose of the study was to identify and investigate the effects rising from using the 3D transient com-puter codes in BWR safety analysis, and their influence on the transient analysis methodology. One of the main questions involves the critical power ratio (CPR) calculation methodology. The present way, where the CPR calculation is per-formed with a separate hot channel calculation, can be artificially conservative. In the investigated cases, no dramatic minimum CPR effect coming from the 3D calculation is apparent. Some cases show some decrease in the transient change of minimum CPR with the 3D calculation, which confirms the general thinking that the 1D calculation is conservative. On the other hand, the observed effect on neutron flux behaviour is quite large. In a slower transient the 3D effect might be stronger. The second part of the report is a summary of a related seminar that was held on the 3D analysis methods. The seminar was sponsored by the Reactor Safety part (NKS-R) of the Nordic Nuclear Safety Research Programme (NKS). (au)

  17. Recent Progress on 3D Silicon Detectors

    CERN Document Server

    Lange, Jörn

    2015-01-01

    3D silicon detectors, in which the electrodes penetrate the sensor bulk perpendicular to the surface, have recently undergone a rapid development from R\\&D over industrialisation to their first installation in a real high-energy-physics experiment. Since June 2015, the ATLAS Insertable B-Layer is taking first collision data with 3D pixel detectors. At the same time, preparations are advancing to install 3D pixel detectors in forward trackers such as the ATLAS Forward Proton detector or the CMS-TOTEM Proton Precision Spectrometer. For those experiments, the main requirements are a slim edge and the ability to cope with non-uniform irradiation. Both have been shown to be fulfilled by 3D pixel detectors. For the High-Luminosity LHC pixel upgrades of the major experiments, 3D detectors are promising candidates for the innermost pixel layers to cope with harsh radiation environments up to fluences of $2\\times10^{16}$\\,n$_{eq}$/cm$^2$ thanks to their excellent radiation hardness at low operational voltages and ...

  18. Lifting Object Detection Datasets into 3D.

    Science.gov (United States)

    Carreira, Joao; Vicente, Sara; Agapito, Lourdes; Batista, Jorge

    2016-07-01

    While data has certainly taken the center stage in computer vision in recent years, it can still be difficult to obtain in certain scenarios. In particular, acquiring ground truth 3D shapes of objects pictured in 2D images remains a challenging feat and this has hampered progress in recognition-based object reconstruction from a single image. Here we propose to bypass previous solutions such as 3D scanning or manual design, that scale poorly, and instead populate object category detection datasets semi-automatically with dense, per-object 3D reconstructions, bootstrapped from:(i) class labels, (ii) ground truth figure-ground segmentations and (iii) a small set of keypoint annotations. Our proposed algorithm first estimates camera viewpoint using rigid structure-from-motion and then reconstructs object shapes by optimizing over visual hull proposals guided by loose within-class shape similarity assumptions. The visual hull sampling process attempts to intersect an object's projection cone with the cones of minimal subsets of other similar objects among those pictured from certain vantage points. We show that our method is able to produce convincing per-object 3D reconstructions and to accurately estimate cameras viewpoints on one of the most challenging existing object-category detection datasets, PASCAL VOC. We hope that our results will re-stimulate interest on joint object recognition and 3D reconstruction from a single image. PMID:27295458

  19. Biocompatible 3D Matrix with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Alberto Ion

    2016-01-01

    Full Text Available The aim of this study was to develop, characterize and assess the biological activity of a new regenerative 3D matrix with antimicrobial properties, based on collagen (COLL, hydroxyapatite (HAp, β-cyclodextrin (β-CD and usnic acid (UA. The prepared 3D matrix was characterized by Scanning Electron Microscopy (SEM, Fourier Transform Infrared Microscopy (FT-IRM, Transmission Electron Microscopy (TEM, and X-ray Diffraction (XRD. In vitro qualitative and quantitative analyses performed on cultured diploid cells demonstrated that the 3D matrix is biocompatible, allowing the normal development and growth of MG-63 osteoblast-like cells and exhibited an antimicrobial effect, especially on the Staphylococcus aureus strain, explained by the particular higher inhibitory activity of usnic acid (UA against Gram positive bacterial strains. Our data strongly recommend the obtained 3D matrix to be used as a successful alternative for the fabrication of three dimensional (3D anti-infective regeneration matrix for bone tissue engineering.

  20. 3D bioprinting for engineering complex tissues.

    Science.gov (United States)

    Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho

    2016-01-01

    Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies.

  1. 3D culture for cardiac cells.

    Science.gov (United States)

    Zuppinger, Christian

    2016-07-01

    This review discusses historical milestones, recent developments and challenges in the area of 3D culture models with cardiovascular cell types. Expectations in this area have been raised in recent years, but more relevant in vitro research, more accurate drug testing results, reliable disease models and insights leading to bioartificial organs are expected from the transition to 3D cell culture. However, the construction of organ-like cardiac 3D models currently remains a difficult challenge. The heart consists of highly differentiated cells in an intricate arrangement.Furthermore, electrical “wiring”, a vascular system and multiple cell types act in concert to respond to the rapidly changing demands of the body. Although cardiovascular 3D culture models have been predominantly developed for regenerative medicine in the past, their use in drug screening and for disease models has become more popular recently. Many sophisticated 3D culture models are currently being developed in this dynamic area of life science. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  2. Particle Acceleration in 3D Magnetic Reconnection

    Science.gov (United States)

    Dahlin, J.; Drake, J. F.; Swisdak, M.

    2015-12-01

    Magnetic reconnection is an important driver of energetic particles in phenomena such as magnetospheric storms and solar flares. Using kinetic particle-in-cell (PIC) simulations, we show that the stochastic magnetic field structure which develops during 3D reconnection plays a vital role in particle acceleration and transport. In a 2D system, electrons are trapped in magnetic islands which limits their energy gain. In a 3D system, however, the stochastic magnetic field enables the energetic electrons to access volume-filling acceleration regions and therefore gain energy much more efficiently than in the 2D system. We also examine the relative roles of two important acceleration drivers: parallel electric fields and a Fermi mechanism associated with reflection of charged particles from contracting field lines. We find that parallel electric fields are most important for accelerating low energy particles, whereas Fermi reflection dominates energetic particle production. We also find that proton energization is reduced in the 3D system.

  3. Participation and 3D Visualization Tools

    DEFF Research Database (Denmark)

    Mullins, Michael; Jensen, Mikkel Holm; Henriksen, Sune;

    2004-01-01

    With a departure point in a workshop held at the VR Media Lab at Aalborg University , this paper deals with aspects of public participation and the use of 3D visualisation tools. The workshop grew from a desire to involve a broad collaboration between the many actors in the city through using new...... perceptions of architectural representation in urban design where 3D visualisation techniques are used. It is the authors? general finding that, while 3D visualisation media have the potential to increase understanding of virtual space for the lay public, as well as for professionals, the lay public require...... communication and visualisation media. It is largely experimental in nature and has a qualitative approach in analysing some of the actions and arguments which took place. These experiences and preliminary results form the basis for a discussion towards an understanding of virtual space and the varying...

  4. 3D Printed Multimaterial Microfluidic Valve

    Science.gov (United States)

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  5. 3D face analysis for demographic biometrics

    Energy Technology Data Exchange (ETDEWEB)

    Tokola, Ryan A [ORNL; Mikkilineni, Aravind K [ORNL; Boehnen, Chris Bensing [ORNL

    2015-01-01

    Despite being increasingly easy to acquire, 3D data is rarely used for face-based biometrics applications beyond identification. Recent work in image-based demographic biometrics has enjoyed much success, but these approaches suffer from the well-known limitations of 2D representations, particularly variations in illumination, texture, and pose, as well as a fundamental inability to describe 3D shape. This paper shows that simple 3D shape features in a face-based coordinate system are capable of representing many biometric attributes without problem-specific models or specialized domain knowledge. The same feature vector achieves impressive results for problems as diverse as age estimation, gender classification, and race classification.

  6. Spectroradiometric characterization of autostereoscopic 3D displays

    Science.gov (United States)

    Rubiño, Manuel; Salas, Carlos; Pozo, Antonio M.; Castro, J. J.; Pérez-Ocón, Francisco

    2013-11-01

    Spectroradiometric measurements have been made for the experimental characterization of the RGB channels of autostereoscopic 3D displays, giving results for different measurement angles with respect to the normal direction of the plane of the display. In the study, 2 different models of autostereoscopic 3D displays of different sizes and resolutions were used, making measurements with a spectroradiometer (model PR-670 SpectraScan of PhotoResearch). From the measurements made, goniometric results were recorded for luminance contrast, and the fundamental hypotheses have been evaluated for the characterization of the displays: independence of the RGB channels and their constancy. The results show that the display with the lower angle variability in the contrast-ratio value and constancy of the chromaticity coordinates nevertheless presented the greatest additivity deviations with the measurement angle. For both displays, when the parameters evaluated were taken into account, lower angle variability consistently resulted in the 2D mode than in the 3D mode.

  7. DNA origami design of 3D nanostructures

    DEFF Research Database (Denmark)

    Andersen, Ebbe Sloth; Nielsen, Morten Muhlig

    2009-01-01

    [8]. We have recently developed a semi-automated DNA origami software package [9] that uses a 2D sequence editor in conjunction with several automated tools to facilitate the design process. Here we extend the use of the program for designing DNA origami structures in 3D and show the application......Structural DNA nanotechnology has been heavily dependent on the development of dedicated software tools for the design of unique helical junctions, to define unique sticky-ends for tile assembly, and for predicting the products of the self-assembly reaction of multiple DNA strands [1-3]. Recently......, several dedicated 3D editors for computer-aided design of DNA structures have been developed [4-7]. However, many of these tools are not efficient for designing DNA origami structures that requires the design of more than 200 unique DNA strands to be folded along a scaffold strand into a defined 3D shape...

  8. The CIFIST 3D model atmosphere grid

    CERN Document Server

    Ludwig, H -G; Steffen, M; Freytag, B; Bonifacio, P

    2009-01-01

    Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of radiation from individual stars and stellar populations. 3D model atmospheres are now on the verge of becoming generally available for a wide range of stellar atmospheric parameters. We report on efforts to develop a grid of 3D model atmospheres for late-type stars within the CIFIST Team at Paris Observatory. The substantial demands in computational and human labor for the model production and post-processing render this apparently mundane task a challenging logistic exercise. At the moment the CIFIST grid comprises 77 3D model atmospheres with emphasis on dwarfs of solar and sub-solar metallicities. While the model production is still ongoing, first applications are already worked upon by the CIFIST Team and collaborators.

  9. 3D Gravity Inversion using Tikhonov Regularization

    Directory of Open Access Journals (Sweden)

    Toushmalani Reza

    2015-08-01

    Full Text Available Subsalt exploration for oil and gas is attractive in regions where 3D seismic depth-migration to recover the geometry of a salt base is difficult. Additional information to reduce the ambiguity in seismic images would be beneficial. Gravity data often serve these purposes in the petroleum industry. In this paper, the authors present an algorithm for a gravity inversion based on Tikhonov regularization and an automatically regularized solution process. They examined the 3D Euler deconvolution to extract the best anomaly source depth as a priori information to invert the gravity data and provided a synthetic example. Finally, they applied the gravity inversion to recently obtained gravity data from the Bandar Charak (Hormozgan, Iran to identify its subsurface density structure. Their model showed the 3D shape of salt dome in this region

  10. 3D Printed Multimaterial Microfluidic Valve.

    Science.gov (United States)

    Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  11. Multiplane 3D superresolution optical fluctuation imaging

    CERN Document Server

    Geissbuehler, Stefan; Godinat, Aurélien; Bocchio, Noelia L; Dubikovskaya, Elena A; Lasser, Theo; Leutenegger, Marcel

    2013-01-01

    By switching fluorophores on and off in either a deterministic or a stochastic manner, superresolution microscopy has enabled the imaging of biological structures at resolutions well beyond the diffraction limit. Superresolution optical fluctuation imaging (SOFI) provides an elegant way of overcoming the diffraction limit in all three spatial dimensions by computing higher-order cumulants of image sequences of blinking fluorophores acquired with a conventional widefield microscope. So far, three-dimensional (3D) SOFI has only been demonstrated by sequential imaging of multiple depth positions. Here we introduce a versatile imaging scheme which allows for the simultaneous acquisition of multiple focal planes. Using 3D cross-cumulants, we show that the depth sampling can be increased. Consequently, the simultaneous acquisition of multiple focal planes reduces the acquisition time and hence the photo-bleaching of fluorescent markers. We demonstrate multiplane 3D SOFI by imaging the mitochondria network in fixed ...

  12. 3D-printed microfluidic devices.

    Science.gov (United States)

    Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-20

    Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices.

  13. Fabrication of 3D nanostructures by multidirectional UV lithography and predictive structural modeling

    Science.gov (United States)

    Kim, Jungkwun; Kim, Cheolbok; Allen, Mark G.; ‘YK' Yoon, Yong-Kyu

    2015-02-01

    This paper presents the fabrication and modeling of three-dimensional (3D) nanostructures by automated multidirectional ultraviolet (UV) lithography, which is a fast, cost-effective, manufacturable fabrication method. Multidirectional UV exposure is performed using a static UV light source equipped with a tilt-rotational substrate holder. A glass substrate with a nanopatterned chrome layer is utilized as both a photomask and a substrate, for which a backside UV exposure scheme is used. For the analytical modeling of the shape of fabricated nanostructures, UV exposure dosage, diffraction and refraction effects, and absorption rate are taken into account. For more accurate process predictive models, a commercially available multiphysics simulation tool is used. The structural shapes predicted from analytical calculation and simulation are compared with the fabricated ones for which various 3D nanoscale test structures are fabricated such as an inclined nanopillar array and a vertical triangular slab. Also, nanostructures with multiple heights are successfully implemented from single layer photoresist by controlling the UV exposure dosage and tilt angles. A tripod embedded horn and a triangular-slab embedded horn are demonstrated.

  14. Design and Implementation of 3D Model Database for General-Purpose 3D GIS

    Institute of Scientific and Technical Information of China (English)

    XU Weiping; ZHU Qing; DU Zhiqiang; ZHANG Yeting

    2010-01-01

    To improve the reusability of three-dimensional (3D) models and simplify the complexity of natural scene reconstruction, this paper presents a 3D model database for universal 3D GIS. After the introduction of its extensible function architecture,accompanied by the conclusion of implicit spatial-temporal hierarchy of models in any reconstructed scene of 3D GIS for general purpose, several key issues are discussed in detail, such as the storage and management of 3D models and related retrieval and load method, as well as the interfaces for further on-demand development. Finally, the validity and feasibility of this model database are proved through its application in the development of 3D visualization system of railway operation.

  15. X3d2pov. Traductor of X3D to POV-Ray

    Directory of Open Access Journals (Sweden)

    Andrea Castellanos Mendoza

    2011-01-01

    Full Text Available High-quality and low-quality interactive graphics represent two different approaches to computer graphics’ 3D object representation. The former is mainly used to produce high computational cost movie animation. The latter is used for producing interactive scenes as part of virtual reality environments. Many file format specifications have appeared to satisfy underlying model needs; POV-ray (persistence of vision is an open source specification for rendering photorealistic images with the ray tracer algorithm and X3D (extendable 3D as the VRML successor standard for producing web virtual-reality environments written in XML. X3D2POV has been introduced to render high-quality images from an X3D scene specification; it is a grammar translator tool from X3D code to POV-ray code.

  16. 3D scene reconstruction based on 3D laser point cloud combining UAV images

    Science.gov (United States)

    Liu, Huiyun; Yan, Yangyang; Zhang, Xitong; Wu, Zhenzhen

    2016-03-01

    It is a big challenge capturing and modeling 3D information of the built environment. A number of techniques and technologies are now in use. These include GPS, and photogrammetric application and also remote sensing applications. The experiment uses multi-source data fusion technology for 3D scene reconstruction based on the principle of 3D laser scanning technology, which uses the laser point cloud data as the basis and Digital Ortho-photo Map as an auxiliary, uses 3DsMAX software as a basic tool for building three-dimensional scene reconstruction. The article includes data acquisition, data preprocessing, 3D scene construction. The results show that the 3D scene has better truthfulness, and the accuracy of the scene meet the need of 3D scene construction.

  17. 3D-skannauksen hyödyntäminen 3D-tulostuksessa

    OpenAIRE

    Seppälä, Mikko

    2016-01-01

    Opinnäytetyössä tutustuttiin 3D-skannaus- ja 3D-tulostusteknologioihin. Työssä käytiin läpi erilaiset 3D-tulostusmenetelmät ja esiteltiin erilaisia 3D-skannausmenetelmiä. Lisäksi käytiin läpi 3D-skannaus- ja 3D-tulostusprosessi. Tavoitteena opinnäytetyössä oli tutkia, kuinka nämä kaksi teknologiaa toimivat yhdessä. Tarkoituksena oli käydä läpi prosessi, jossa fyysinen kappale skannattiin digitaaliseen muotoon, jonka jälkeen se voidaan tulostaa uudeksi fyysiseksi kappaleeksi. Lisäksi tarko...

  18. A 3D-printed high power nuclear spin polarizer.

    Science.gov (United States)

    Nikolaou, Panayiotis; Coffey, Aaron M; Walkup, Laura L; Gust, Brogan M; LaPierre, Cristen D; Koehnemann, Edward; Barlow, Michael J; Rosen, Matthew S; Goodson, Boyd M; Chekmenev, Eduard Y

    2014-01-29

    Three-dimensional printing with high-temperature plastic is used to enable spin exchange optical pumping (SEOP) and hyperpolarization of xenon-129 gas. The use of 3D printed structures increases the simplicity of integration of the following key components with a variable temperature SEOP probe: (i) in situ NMR circuit operating at 84 kHz (Larmor frequencies of (129)Xe and (1)H nuclear spins), (ii) 3D printing dramatically reduces production time and expenses while allowing reproducibility and integration of "off-the-shelf" components and enables the concept of printing on demand. The utility of this SEOP setup is demonstrated here to obtain near-unity (129)Xe polarization values in a 0.5 L optical pumping cell, including ∼74 ± 7% at 1000 Torr xenon partial pressure, a record value at such high Xe density. Values for the (129)Xe polarization exponential build-up rate [(3.63 ± 0.15) × 10(-2) min(-1)] and in-cell (129)Xe spin-lattice relaxation time (T1 = 2.19 ± 0.06 h) for 1000 Torr Xe were in excellent agreement with the ratio of the gas-phase polarizations for (129)Xe and Rb (PRb ∼ 96%). Hyperpolarization-enhanced (129)Xe gas imaging was demonstrated with a spherical phantom following automated gas transfer from the polarizer. Taken together, these results support the development of a wide range of chemical, biochemical, material science, and biomedical applications.

  19. High Current Density 2D/3D Esaki Tunnel Diodes

    CERN Document Server

    Krishnamoorthy, Sriram; Lee, Choong Hee; Zhang, Yuewei; McCulloch, William D; Johnson, Jared M; Hwang, Jinwoo; Wu, Yiying; Rajan, Siddharth

    2016-01-01

    The integration of two-dimensional materials such as transition metal dichalcogenides with bulk semiconductors offer interesting opportunities for 2D/3D heterojunction-based novel device structures without any constraints of lattice matching. By exploiting the favorable band alignment at the GaN/MoS2 heterojunction, an Esaki interband tunnel diode is demonstrated by transferring large area, Nb-doped, p-type MoS2 onto heavily n-doped GaN. A peak current density of 446 A/cm2 with repeatable room temperature negative differential resistance, peak to valley current ratio of 1.2, and minimal hysteresis was measured in the MoS2/GaN non-epitaxial tunnel diode. A high current density of 1 kA/cm2 was measured in the Zener mode (reverse bias) at -1 V bias. The GaN/MoS2 tunnel junction was also modeled by treating MoS2 as a bulk semiconductor, and the electrostatics at the 2D/3D interface was found to be crucial in explaining the experimentally observed device characteristics.

  20. Body Language Advanced 3D Character Rigging

    CERN Document Server

    Allen, Eric; Fong, Jared; Sidwell, Adam G

    2011-01-01

    Whether you're a professional Character TD or just like to create 3D characters, this detailed guide reveals the techniques you need to create sophisticated 3D character rigs that range from basic to breathtaking. Packed with step-by-step instructions and full-color illustrations, Body Language walks you through rigging techniques for all the body parts to help you create realistic and believable movements in every character you design. You'll learn advanced rigging concepts that involve MEL scripting and advanced deformation techniques and even how to set up a character pipeline.