Fracture Energy Measurement in Different Concrete Grades

Fracture energy is regarded as an intrinsic (material) property to dominate crack mechanisms and associated crack growth to concrete damage under applied stress. More recently, huge evolution in computing technology leading to finite element analysis (FEA) approaches to require incorporation of constitutive model, such as traction-separation relationship derived from state-of-the-art fracture mechanics fundamental. A physically-based models requires fracture energy values; therefore, properly measured fracture energy value is essential to exhibit better structures response within FEA models. Large arrays of parameters involved during concrete mixture such as beam size effect, aggregate size and concrete grade to affect the flexural resistance in concrete. The fracture and failure in concrete ahead of crack tip is represented by fracture energy values where micro-damage events occurred such as interfacial failure, fiber-bridging and matrix cracking. This study aims to investigate the fracture energy of concrete specimens with combination of notch depth ao at mid-span, design concrete strength as specified in the testing series. Independent compression strength, fc and measured load-displacement profiles under three-points bending test were used to determine fracture energy by incorporating three available fracture energy expressions such as Bazant, Hillerborg and CEB-FIP models

Fracture Energy Measurement in Different Concrete Grades

Fracture energy is regarded as an intrinsic (material) property to dominate crack mechanisms and associated crack growth to concrete damage under applied stress. More recently, huge evolution in computing technology leading to finite element analysis (FEA) approaches to require incorporation of constitutive model, such as traction-separation relationship derived from state-of-the-art fracture mechanics fundamental. A physically-based models requires fracture energy values; therefore, properly measured fracture energy value is essential to exhibit better structures response within FEA models. Large arrays of parameters involved during concrete mixture such as beam size effect, aggregate size and concrete grade to affect the flexural resistance in concrete. The fracture and failure in concrete ahead of crack tip is represented by fracture energy values where micro-damage events occurred such as interfacial failure, fiber-bridging and matrix cracking. This study aims to investigate the fracture energy of concrete specimens with combination of notch depth ao at mid-span, design concrete strength as specified in the testing series. Independent compression strength, fc and measured load-displacement profiles under three-points bending test were used to determine fracture energy by incorporating three available fracture energy expressions such as Bazant, Hillerborg and CEB-FIP models

Josephson Current between Triplet and Singlet Superconductors

The Josephson effect between triplet and singlet superconductors is studied. Josephson current can flow between triplet and singlet superconductors due to the spin-orbit coupling in the spin-triplet superconductor but it is finite only when triplet superconductor has $L_z=-S_z=\pm 1$, where $L_z$ and $S_z$ are the perpendicular components of orbital angular momentum and spin angular momentum of the triplet Cooper pairs, respectively. The recently observed temperature and orientational dependence of the critical current through a Josephson junction between UPt$_3$ and Nb is investigated by considering a non-unitary triplet state.Comment: 4 pages, no figure

Materials, photophysics and device engineering of perovskite light-emitting diodes

Here we provide a comprehensive review of a newly developed lighting technology based on metal halide perovskites (i.e. perovskite light-emitting diodes) encompassing the research endeavours into materials, photophysics and device engineering. At the outset we survey the basic perovskite structures and their various dimensions (namely three-, two- and zero-dimensional perovskites), and demonstrate how the compositional engineering of these structures affects the perovskite light-emitting properties. Next, we turn to the physics underpinning photo- and electroluminescence in these materials through their connection to the fundamental excited states, energy/charge transport processes and radiative and non-radiative decay mechanisms. In the remainder of the review, we focus on the engineering of perovskite light-emitting diodes, including the history of their development as well as an extensive analysis of contemporary strategies for boosting device performance. Key concepts include balancing the electron/hole injection, suppression of parasitic carrier losses, improvement of the photoluminescence quantum yield and enhancement of the light extraction. Overall, this review reflects the current paradigm for perovskite lighting, and is intended to serve as a foundation to materials and device scientists newly working in this field

Asymmetric Fermi superfluid in a harmonic trap

We consider a dilute two-component atomic fermion gas with unequal populations in a harmonic trap potential using the mean field theory and the local density approximation. We show that the system is phase separated into concentric shells with the superfluid in the core surrounded by the normal fermion gas in both the weak-coupling BCS side and near the Feshbach resonance. In the strong-coupling BEC side, the composite bosons and left-over fermions can be mixed. We calculate the cloud radii and compare axial density profiles systemically for the BCS, near resonance and BEC regimes.Comment: 15 pages, 5 figure

Collective Modes in a Dilute Bose-Fermi Mixture

We here study the collective excitations of a dilute spin-polarized Bose-Fermi mixture at zero temperature, considering in particular the features arising from the interaction between the two species. We show that a propagating zero-sound mode is possible for the fermions even when they do not interact among themselves.Comment: latex, 6 eps figure

Heat shock proteins and neurodegenerative disorders

10.1100/tsw.2008.48TheScientificWorldJournal8270-27

Fracture energy measurement in different concrete grades

Fracture energy is regarded as an intrinsic (material) properties that dominates crack mechanisms and associated crack growth in concrete damage under applied stress. In recent times, significant advancements in computing technology have driven the adoption of finite element analysis (FEA) methodologies that necessitate the integration of constitutive models, including the traction-separation relationship derived from cutting-edge fracture mechanics. A physically-based model requires fracture energy values; therefore, a properly measured fracture energy value is essential to exhibit better structure response within FEA models. There are large arrays of parameters involved during the concrete mixture, such as beam size effect, aggregate size, and concrete grade, that affect the flexural resistance of the concrete. The fracture and failure in concrete ahead of the crack tip are represented by fracture energy values where micro-damage events such as interfacial failure, fiber-bridging, and matrix cracking occurred. This study aims to determine the fracture energy of concrete specimens with combination of notch depth ao at mid-span, design concrete strength as specified in the testing series. Independent compression strength, fc and measured load-displacement profiles under a three-point bending test were used to determine fracture energy by incorporating three available fracture energy expressions such as Bazant, Hillerborg, and CEB-FIP models

Ground-state properties of trapped Bose-Fermi mixtures: role of exchange-correlation

We introduce Density Functional Theory for inhomogeneous Bose-Fermi mixtures, derive the associated Kohn-Sham equations, and determine the exchange-correlation energy in local density approximation. We solve numerically the Kohn-Sham system and determine the boson and fermion density distributions and the ground-state energy of a trapped, dilute mixture beyond mean-field approximation. The importance of the corrections due to exchange--correlation is discussed by comparison with current experiments; in particular, we investigate the effect of of the repulsive potential energy contribution due to exchange--correlation on the stability of the mixture against collapse.Comment: 6 pages, 4 figures (final version as published in Physical Review

Theory of the Transition at 0.2 K in Ni-doped Bi2Sr2CaCu2O8

A theory is put forward that the electronic phase transition at 0.2 K in Ni-doped Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ is result of the formation of a spin density wave in the system of Ni impurities. The driving force for the transition is the exchange interaction between the impurity spins and the spins of the conduction electrons. This creates a small gap at two of the four nodes of the superconducting gap. The effect is to reduce the thermal conductivity by a factor of two, as observed.Comment: 10 pages and 1 figur