Electric and magnetic dipole coupling in near-infrared split ring metamaterial arrays

We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared (1.4 $\mu$m) planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts agree well with a simple model with simultaneous magnetic and electric near-field dipole coupling. We also find large broadening of the resonance, accompanied by a decrease in effective cross section per SRR with increasing density. These effects result from superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches to metamaterials.Comment: 4 pages, 4 color figure

Optimal conversion of Bose condensed atoms into molecules via a Feshbach resonance

In many experiments involving conversion of quantum degenerate atomic gases into molecular dimers via a Feshbach resonance, an external magnetic field is linearly swept from above the resonance to below resonance. In the adiabatic limit, the fraction of atoms converted into molecules is independent of the functional form of the sweep and is predicted to be 100%. However, for non-adiabatic sweeps through resonance, Landau-Zener theory predicts that a linear sweep will result in a negligible production of molecules. Here we employ a genetic algorithm to determine the functional time dependence of the magnetic field that produces the maximum number of molecules for sweep times that are comparable to the period of resonant atom-molecule oscillations, $2\pi\Omega_{Rabi}^{-1}$. The optimal sweep through resonance indicates that more than 95% of the atoms can be converted into molecules for sweep times as short as $2\pi\Omega_{Rabi}^{-1}$ while the linear sweep results in a conversion of only a few percent. We also find that the qualitative form of the optimal sweep is independent of the strength of the two-body interactions between atoms and molecules and the width of the resonance

Fatigue delamination behaviour of unidirectional carbon fibre/epoxy laminates reinforced by Z-Fiber® pinnin

-Pin reinforced carbon-fibre epoxy laminates were tested under Mode I and Mode II conditions, both quasi-statically and in fatigue. Test procedures were adapted from existing standard or pre-standard tests. Samples containing 2% and 4% areal densities of carbon-fibre Z-pins (0.28mm diameter) were compared with unpinned laminates. Quasi-static tests under displacement control yielded a dramatic increase of the apparent delamination resistance. Specimens with 2% pin density failed in Mode I at loads 170N, equivalent to an apparent GIC of 2kJ/m2. Fatigue testing under load control showed that the presence of the through- thickness reinforcement slowed down fatigue delamination propagation

Improved impact performance of marine sandwich panels using through-thickness reinforcement: Experimental results

This paper presents results from a test developed to simulate the water impact (slamming) loading of sandwich boat structures. A weighted elastomer ball is dropped from increasing heights onto rigidly supported panels until damage is detected. Results from this test indicate that honeycomb core sandwich panels, the most widely used material for racing yacht hulls, start to damage due to core crushing at impact energies around 550 J. Sandwich panels of the same areal weight and with the same carbon/epoxy facings but using a novel foam core reinforced in the thickness direction with pultruded carbon fibre pins, do not show signs of damage until above 1200 J impact energy. This suggests that these will offer significantly improved resistance to wave impact. Quasi-static test results cannot be used to predict impact resistance here as the crush strength of the pinned foam is more sensitive to loading rate than that of the honeycomb core

Sex Differences in the Effect of Inflammation on Subjective Social Status: A Randomized Controlled Trial of Endotoxin in Healthy Young Adults.

It has been established that inflammation leads to a variety of changes in social experience, but one area of social experience that has been overlooked is subjective social status. Furthermore, given sex differences in the relationship between inflammation and social status, males may be more sensitive to inflammation-induced changes in social status. However, no previous studies in humans have examined this possibility. In the present study, healthy young participants (n = 115) were randomly assigned to receive either endotoxin, an experimental inflammatory challenge, or placebo. Participants reported their subjective social status at baseline (prior to injection), and approximately 2 h later (time of peak inflammatory response for the endotoxin group). Results, using ANCOVA analyses, indicated that males exposed to endotoxin, but not females, reported lower levels of subjective social status at the peak of inflammatory response (vs. placebo). These results suggest that males may be more sensitive to the effects of inflammation in certain social domains, such as perceived social status. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01671150

Fast Converging Path Integrals for Time-Dependent Potentials I: Recursive Calculation of Short-Time Expansion of the Propagator

In this and subsequent paper arXiv:1011.5185 we develop a recursive approach for calculating the short-time expansion of the propagator for a general quantum system in a time-dependent potential to orders that have not yet been accessible before. To this end the propagator is expressed in terms of a discretized effective potential, for which we derive and analytically solve a set of efficient recursion relations. Such a discretized effective potential can be used to substantially speed up numerical Monte Carlo simulations for path integrals, or to set up various analytic approximation techniques to study properties of quantum systems in time-dependent potentials. The analytically derived results are numerically verified by treating several simple models.Comment: 29 pages, 5 figure

Use of microfasteners to produce damage tolerant composite structures

The paper concerns the mechanical performance of continuous fibre/thermosetting polymer matrix composites reinforced in the through-thickness direction with fibrous or metallic rods or threads in order to mitigate against low delamination resistance. Specific illustrations of the effects of microfasteners in reducing delamination crack growth are made for Z-pinned and tufted composites. Response to loading in such ‘structured materials’ is subject to multiple parameters defining their in-plane and out-of-plane properties. Single microfastener mechanical tests are well suited to establish the crack bridging laws under a range of loading modes, from simple delamination crack opening to shear, and provide the basis for predicting the corresponding response of microfastener arrays, within a given material environment. The fundamental experiments on microfasteners can be used to derive analytical expressions to describe the crack bridging behaviour in a general sense, to cover all possible loadings. These expressions can be built into cohesive element constitutive laws in a finite-element framework for modelling the effects of microfastener arrays on the out-of-plane mechanical response of reinforced structural elements, including the effects of known manufacturing imperfections. Such predictive behaviour can then be used to assess structural integrity under complex loading, as part of the component design process. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’

Faktor- Faktor Yang Mempengaruhi Minat Perilaku Wajib Pajak Untuk Menggunakan E-filing

Penelitian ini bertujuan untuk mengetahui faktor-faktor apa saja yang mempengaruhi Wajib Pajak dalam menggunakan e-filing di Kota Kediri. Variabel yang digunakan dalam penelitian ini adalah variabel persepsi terhadap kegunaan, persepsi kemudahan, kesukarelaan, faktor sosial.Data yang diperoleh merupakan hasil dari pengisian kuesioner yang dilakukan oleh responden, yaitu sebanyak 167 Wajib Pajak Orang Pribadi (kayawan) yang menggunakan e-filing di Kota Kediri. Data kuesioner diuji dengan uji validitas, uji reliabilitas, uji asumsi klasik, dan menguji hipotesis menggunakan regresi , uji t dan uji dengan program SPSS versi 13.Kesimpulan dari penelitian ini adalah Persepsi terhadap Kegunaan (X1) berpengaruh terhadap minat Wajib Pajak dalam menggunakan e-filing, Persepsi Kemudahan (X2) berpengaruh terhadap minat Wajib Pajak dalam menggunakan e-filing, Kesukarelaan (X3) berpengaruh terhadap minat Wajib Pajak dalam menggunakan e-filing,Faktor Sosial (X4) berpengaruh terhadap minat Wajib Pajak dalam menggunakan e-filing

Influence of combined emulsifier on physical characteristics of fat filling

The influence of mixture of two separate emulsifiers and a new generation of emulsifier 2 in 1, which nowadays has a tendency to replace these two, on the rheological and textural properties and sensory quality of fat filling was investigated. Emulsifiers were added in concentrations of 0.3, 0.45 and 0.75%, and calculated on the total mass of raw materials. The addition of emulsifiers in concentrations of 0.3 and 0.45% had a significant influence on the textural and rheological parameters of fat filling. These results showed that is not necessary to add a maximum amount of an emulsifier in order to achieve optimal spreadibility and hardness, which is certainly justified from an economic point of view. The addition of emulsifier 2 in 1 caused starchy taste and migration of fat to the surface of fat filling. The sample with 0.45%, which was a combination of two emulsifiers, had the best sensory quality and spreadability characteristics