scholarly journals THE FOLIATED LEFSCHETZ HYPERPLANE THEOREM

2017 ◽  
Vol 231 ◽  
pp. 115-127
Author(s):  
DAVID MARTÍNEZ TORRES ◽  
ÁLVARO DEL PINO ◽  
FRANCISCO PRESAS
Keyword(s):  
Transverse Geometry

A foliation$(M,{\mathcal{F}})$is said to be$2$-calibrated if it admits a closed 2-form$\unicode[STIX]{x1D714}$making each leaf symplectic. By using approximately holomorphic techniques, a sequence$W_{k}$of$2$-calibrated submanifolds of codimension-$2$can be found for$(M,{\mathcal{F}},\unicode[STIX]{x1D714})$. Our main result says that the Lefschetz hyperplane theorem holds for the pairs$(F,F\cap W_{k})$, with$F$any leaf of${\mathcal{F}}$. This is applied to draw important consequences on the transverse geometry of such foliations.

Thermal Expansion of Three-Phase Composite Materials

1989 ◽  
Vol 56 (2) ◽  
pp. 418-422 ◽  
Author(s):  
George J. Dvorak ◽  
Tungyang Chen
Keyword(s):  
Thermal Expansion ◽  
Heterogeneous Media ◽  
Transversely Isotropic ◽  
Local Fields ◽  
Stress Fields ◽  
Cylindrical Shape ◽  
Thermal Expansion Coefficients ◽  
Decomposition Procedure ◽  
Transverse Geometry ◽  
Expansion Coefficients

Exact expressions are found for overall thermal expansion coefficients of a composite medium consisting of three perfectly-bonded transversely isotropic phases of cylindrical shape and arbitrary transverse geometry. The results show that macroscopic thermal expansion coefficients depend only on the thermoelastic constants and volume fractions of the phases, and on the overall compliance. The derivation is based on a decomposition procedure which indicates that spatially uniform elastic strain fields can be created in certain heterogeneous media by superposition of uniform phase thermal strains with local strains caused by piecewise uniform stress fields, which are in equilibrium with prescribed surface tractions. The procedure also allows evaluation of thermal stress fields in the aggregate in terms of known local fields caused by axisymmetric overall stresses. Finally, averages of local fields are found with the help of known mechanical stress and strain concentration factors.

scholarly journals Aberration correction for direct laser written waveguides in a transverse geometry

2016 ◽  
Vol 24 (10) ◽  
pp. 10565 ◽  
Author(s):  
L. Huang ◽  
P. S. Salter ◽  
F. Payne ◽  
M. J. Booth
Keyword(s):  
Aberration Correction ◽  
Transverse Geometry ◽  
Direct Laser

Slow and fast light in photorefractive GaAs–AlGaAs multiple quantum wells in transverse geometry

2010 ◽  
Vol 108 (6) ◽  
pp. 063101 ◽  
Author(s):  
Fang Bo ◽  
Ze Liu ◽  
Feng Gao ◽  
Guoquan Zhang ◽  
Jingjun Xu
Keyword(s):  
Quantum Wells ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Transverse Geometry ◽  
Fast Light ◽  
Slow And Fast Light

MAGNETIC BEHAVIOR OF MAGNESIUM DIBORIDE SUPERCONDUCTING THIN FILMS

2003 ◽  
Vol 17 (04n06) ◽  
pp. 597-601
Author(s):  
G. GRIMALDI ◽  
U. GAMBARDELLA ◽  
S. PACE ◽  
V. FERRANDOM ◽  
C. FERDEGHINI ◽  
...  
Keyword(s):  
Thin Films ◽  
Hysteresis Loops ◽  
Annealing Treatment ◽  
Magnetic Behavior ◽  
Anomalous Behavior ◽  
Zero Field ◽  
Superconducting Thin Films ◽  
Double Peak ◽  
Transverse Geometry ◽  
Field Approaches

We report the experimental results of the field H and temperature T dependent magnetization M measurements of MgB 2 superconducting thin films deposited by pulsed laser deposition. MgB 2 thin films were obtained from a precursor layer deposited in UHV at room temperaure from stoichiometric target, then an annealing treatment in Mg atmosphere allowed to crystallize the superconducting phase. From the hysteresis loops at each temperature of measurement the critical current density Jc(H) has been extracted according to Brandt's model for a transverse geometry. At low temperatures an anomalous behavior has been observed in the hysteresis loops: as the exernal magnetic field approaches the zero field region on the upper and lower branches, a double peak of the magnetization occurs. This magnetic flux jumping can be explained within an adiabatic critical state model, and can be ascribed to thermomagnetic instabilities as in bulk samples.

scholarly journals Optimisation Studies of Cylinder Water Channel Geometry in an Internal Combustion Engine

2019 ◽  
Vol 252 ◽  
pp. 04003
Author(s):  
Michał Biały ◽  
Konrad Pietrykowski
Keyword(s):  
Cross Sections ◽  
Heat Dissipation ◽  
Combustion Engine ◽  
Direct Injection ◽  
Water Channel ◽  
Cylinder Wall ◽  
Fixed Temperature ◽  
Channel Geometry ◽  
Pressure Drops ◽  
Transverse Geometry

This paper presents an analysis of the results of simulation studies of optimisation of water channel geometry placed in the head of an opposed-piston three-cylinder engine. For this purpose, six computation cases were prepared, differing in shape and cross-section field of channels located along the axis of one of the cylinders. The research was conducted by means of Ansys Flutent software. The conditions of initiation and boundary have been obtained from previous studies using AVL Boost RT software. A fixed temperature was assumed on the cylinder wall and a fixed temperature was assumed for the coolant at the inlet to the model. The studies were carried out for the model of the designed engine, which carries out a two-stroke diesel cycle. The engine will be equipped with direct injection of diesel fuel. On the basis of the conducted analysis of the test results, the flow velocity distributions and distributions of speed fields of the working medium in the critical cross-sections, the distribution of temperature and heat flow fields were prepared. Pressure drops and heat dissipation were also determined for individual models. This provided the basis for the determination of the influence of the rib's transverse geometry shape on the amount of heat received from the cylinder's smoothing walls.

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