Noise level, inner hair cell damage, audiometric features, and equal-energy hypothesis

Rabbits were exposed to 2- to 7-kHz noise either for a short duration at a high sound-pressure level (15 or 30 min at 115 dB SPL), or a long duration at a low level (512 h at 85 dB SPL). The high-level exposure produced a hearing loss in the frequency range 2-6 kHz, whereas the low-level exposure gave maximum hearing loss at 12-20 kHz. The 115-dB exposure caused significantly more damage to inner hair cells than the 85-dB exposure. The implications of the present results for evaluating audiograms, equal-energy hypothesis, risk criteria, and subjective auditory features are pointed out.     

Parameter estimation for stochastic equations with additive fractional Brownian sheet

We study the maximum likelihood estimator for stochastic equations with additive fractional Brownian sheet. We use the Girsanov transform for the the two-parameter fractional Brownian motion, as well as the Malliavin calculus and Gaussian regularity theory.      

Linear viscoelastic models: Part II. Recovery of the molecular weight distribution using viscosity data

The constitutive models for the viscoelasticity of polymers are presented for determining molecular weight distributions (MWDs) from viscosity measurements. The inversion of this model derived from control theory and melt calibration procedure connects the relaxation modulus, viscosity, and other flow properties of a polymer. The linear principle enables simultaneous and accurate modelling of the relaxation modulus and of viscosity flow curves over a wide range. Starting from viscosity measurements, the new model is used to determine the MWD, linear viscoelastic relaxation moduli, and the relaxation spectra of polyethylene of different grades. In addition, two benchmark analyses of bimodal polystyrene are reported, and the capability of the model is proven by the two-box test of Malkin. The error of the modelled viscosity is smaller than that for previously reported models. One of the main features of this work is that no relaxation time or spectrum procedures were used to generate and model linear viscoelasticity.     

Phase transition at 233 K in [(CH3)4N]2cdI4

Abstract

[(CH₃)₄N]₂cdI₄ exhibits a phase transition at 233 K from Pnma to P2 1/c as shown by single-crystal X-ray measurements and differential scanning calorimetry. The observed entropy change amounts to approximately 8.4 J.mole^?1 K^?1 and the spontaneous strain is about – 18.10^?3. The symmetry change can be interpreted in the framework of the Landau theory.     

The57Fe magnetic hyperfine field in Au-Fe alloys (evidence favoring the two Fe-environment model of Au-Fe alloys)

Conclusions The results of our analysis strongly support our two Fe environment hypothesis. The critical concentration at about 12 at.% suggests that the dependence of H(0,x) on x undergoes a fundamental change at this concentration. Furthermore, the so-called critical concentration at about 17 at.% apparently has little to do with any fundamental alloy property. Rather, it reflects the 12 at.% critical composition when properties are analyzed in terms of the average rather than the local Fe concentration. The two Fe environments appear to have differing configurations.This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.     

Chemisorption of 1,1-dichloroethene on the Si(1 1 1)-7 × 7 surface

Chemisorption of 1,1-dichloroethene (Cl₂CCH₂) to a Si(1 1 1)-7 × 7 surface was studied by means of X-ray photoelectron spectroscopy using synchrotron radiation, recording chlorine 2p and carbon 1s spectra. For carbon 1s, spectral assignment of the chemisorbed species is based on quantum chemical calculations of chemical shifts in model compounds.The results confirm the identity of covalently bonded 1-chlorovinyl (-CClCH₂) and vinylidene (CCH₂) adspecies. Upon chemisorption at room temperature it was found that about one-third of the molecules break one C-Cl bond while about two-thirds of the adsorbates break two C-Cl bonds. We do not, however, find evidence for isomerization of CCH₂ to di-bonded vinylene (-CHCH-).     

Optimization of preparative chromatographic separation of multiple rare earth elements

This work presents a method to optimize multi-product chromatographic systems with multiple objective functions. The system studied is a neodymium, samarium, europium, gadolinium mixture separated in an ion exchange chromatography step. A homogeneous Langmuir Mobile Phase Modified model is calibrated to fit the experiments, and then used to perform the optimization task. For the optimization a multi-objective Differential Evolution algorithm was used, with weighting based on relative value of the components to find optimal operation points along the Pareto front. The objectives of the Pareto front are weighted productivity and weighted yield with purity as an equality constraint. A prioritizing scheme based on relative values is applied for determining the pooling order. A simple rule of thumb for pooling strategy selection is presented. The multi-objective optimization gives a Pareto front which shows the rule of thumb, as a gap in one of the objective functions.     

Proton particle states in the region around 13250Sn82

The decay of ¹³³Sn leading to levels in ¹³³₅₁Sb₈₂, which has one proton outside the closed shell, has been observed at the OSIRIS isotope separator on-line facility. The half-life is 1.47±0.04 sec and the $\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$. level is found at an excitation of 963 keV. The decay of $\text{18±1}\text{sec}{}^{135}\text{Te}$ to one-particle and three-particle levels in ^135₅₃I₈₂ has also been studied.     

Magnetic behavior of amorphous Fe−Ni−Zr alloys and their response to radiation damage

The magnetic properties of two amorphous Fe?Ni?Zr alloys, Fe_89.7Ni_0.03Zr₁₀ and Fe₇₀Ni₂₀Zr₁₀, both in the “as cast” and neutron irradiated states were investigated by Mössbauer spectroscopy and dc magnetic susceptibility measurements. The upper magnetic ordering temperatures of Fe_89.7Ni_0.03Zr₁₀ are 232K and 246K for the “as cast” and irradiated samples, respectively. The magnetic ordering temperature for Fe₇₀Ni₂₀Zr₁₀ was about 478K for both the “as cast” and irradiated samples. Both compositions yield magnetic hyperfine spectra, which show a considerable relaxation effect that must be explicitly considered in the calculation of the average local Fe moments. When this is done, these values derived from Mössbauer spectra are in good agreement with the dc susceptibility values. The effects of neutron irradiation on the magnetic properties of these alloys are small.