Some difficulties for Clifton,Redhead, and Butterfield's recent proof of nonlocality

Clifton, Redhead, and Butterfield have recently produced a generalization of the new non-locality proof due to Greenberger, Horne, and Zeilinger. Their proof is intended to have certain advantages over the standard Belltype arguments. One of these is that, although the proof allows for causally relevant apparatus hidden variables, it avoids the need for making certain standard locality assumptions about those parameters. On closer inspection, the part of the proof which supposedly removes the need for such assumptions is shown to rest on a fallacy. This renders the proof invalid. Two other, related difficulties are explored along the way.1. CRB actually provide two nonlocality proofs, but our concern here is with the first.2. Cf. p.173 for a precise formulation of these. (Any references in these footnotes are to [1].) Note that, due to the way CRB define the µ's, these conditions are not entirely independent.3. Cf. p.174. Note that CRB claim to derive the independence of outcomes from apparatus existents via our other assumptions without imposing any other conditions on their distributions, citing Lemma 2, which we shall object to in Sec. 4 below. This should be given a careful reading; Lemma 2 only purports to derive the statistical independence of outcomes fromlocal (i.e., nearby) apparatus hidden variables. The independence of outcomes fromdistant apparatus hidden variables is assumed, rather, in OL.4. Here, and in many places, I shall rely on [1] for the details.5. CRB have endorsed this definition of M (personal correspondence).6. More precisely, those values of do so for at least one possible quadruple of apparatus existents, and measurement results; and foruncountably many setting quadruples in (p.167).7. Given CRB's way of defining the µ's so as to include the information found in the 's, the terms in OF and most of those in OL would actually be ill-defined in most cases (for each ) inany theory. This is simply because the measuring devices cannot be set to measure in two different directions at once. However, it should be possible to remedy that situation by simply redefining µ so that it includes only information about the state of the apparatus not covered by .8. CRB endorse the first of these two suggestions (personal correspondence).9. I have omitted the arguments fromA,B,C andD. Wherever they appear without arguments they will implicitly have the three with which they were first introduced. Note that M⁺ should ideally be indexed by and , as there is no reason to think that all the same members of M will makeABCD = +1 for different values of and .10. Cf. note 6 above.11. Note that in light of this objection to their proof, we can see that CRB also fail to establish the link they claim exists between TF, strict correlations, and the condition they call TF.TF is the four-particle analogue of the conjunction of Shimony's outcome independence and his parameter independence (p.162). They rest their claim about the link on Lemma 2 (pp.162 and 165).     

Nonlinear vertical accelerations of a floating torus in regular waves

The longitudinal motions and vertical accelerations of a floating torus as well as wave motion inside the torus are studied by model tests in regular deep-water waves. Comparisons are made with linear and partly with second-order potential-flow theory for the smallest examined experimental wave height-to-wave length ratio 1/120. Reasonable agreement is obtained, in particular for the linear problem. The importance of 3D flow, hydroelasticity and strong hydrodynamic frequency dependency is documented. Experimental precision errors and bias errors, for instance, due to tank-wall interference are discussed. Numerical errors due to viscous effects are found to be secondary. Experiments show that the third and fourth harmonic accelerations of the torus matter and cannot be explained by a perturbation method with the wave steepness as a small parameter.     

Importance Sampling for p-value Computations in Multivariate Tests

Abstract

An importance sampling procedure is developed to approximate the distribution of an arbitrary function of the eigenvalues for a matrix beta random matrix or a Wishart random matrix. The procedure is easily implemented and provides confidence intervals for the p-values of many of the commonly used test statistics in multivariate analysis. An adaptive procedure allows for the control of either absolute error or relative error in this p-value estimation through the choice of importance sample size.     

Torsion balances with fibres of zero length

Torsion balances have good immunity to tilt and low rotational stiffness. However precise control of the position of the suspended torsion ‘bob’ is difficult in the presence of ground vibrations and tilt and this is a limiting factor in applications where Casimir forces or putative non-Newtonian short-range forces are being measured. We describe how the desirable characteristics of torsion balances can be reproduced in a rigid body that is suspended using applied forces rather than a torsion fibre. The suspension system can then provide a more precise control of the degrees of freedom of the suspended body. We apply these ideas to a superconducting levitated torsion balance, developed by the authors, and a generic electrostatic suspension. We present results of preliminary experiments that provide support for our analyses.     

Properties of two amide‐based hydrophilic interaction liquid chromatography columns

Hydrophilic interaction liquid chromatography is a separation technique suitable for the separation of moderately and highly polar compounds. Various stationary phases (SPs) for hydrophilic interaction liquid chromatography are commercially available. While the SPs based on the same type of ligand are available from different providers, they can display a distinct retention characteristics and separation selectivity. The current work is focused on characterization and comparison of the separation systems of two amide‐based HPLC columns from two producers, i.e. XBridge Amide column and TSK gel Amide‐80 column. Several characterization procedures (tests) were used to investigate the differences between these columns. The chromatographic behavior of selected analytes indicates that multimodal interactions are responsible for retention and separation on these columns. Multiple testing approaches were used in order to reveal subtle differences between the SPs. Both amide‐based columns showed certain differences in retention, selectivity, and plate counts. Based on the tests used in this study, we conclude that the investigated columns provide a different degree of H‐bonding interactions.     

Monitoring abiotic degradation of branched polyethylenes formulated with pro-oxidants through different mechanical tests

The mechanical properties of two linear low density and low density polyethylenes containing a pro-oxidant additive were monitored during accelerated aging (60 °C in a convection oven) and weather exposure. Tearing tests (trouser) were performed for the first time in polyethylenes subjected to oxo-degradation revealing a transition from an extensible to a non-extensible material, at exposure times when standard tensile tests were not able to detect any changes in the materials. The essential work of fracture (EWF) technique was also applied and the results were in agreement with those of trouser tests. The specific essential work of fracture first increased with exposure time until the sample experienced a transition to a less ductile state where EWF was no longer applicable. EWF and trouser tear tests were more sensitive detecting the onset of degradation probably because they employ notched specimens that impose more critical stress concentration conditions than conventional tensile tests.     

Effect of Process Variable on the Gelation Time of Sulfonated Polyacrylamide Nanocomposite Hydrogel

Among the methods available to reduce water production during oil recovery, injecting a gelling system composed of a polymer and a crosslinker has been widely used. In this study, a Plackett-Burman design was used for screening a large number of factors such as concentrations of polymer, crosslinker, pH, temperature, and presence or absence of NaCl, CaCl₂, MgCl₂, KCl, thiourea, sodium lactate, and nanoclay on the gelation time of sulfonated polyacrylamide nanocomposite hydrogels by rheological tests. Among these factors, temperature, pH, and CaCl₂ concentration were found to have the greatest effect on the gelation time. The effects of these three factors and their interactions on the gelation time were then determined by using central composite design of response surface method. As a result, the interactions of CaCl₂ concentration with temperature and pH were considerably more than the interactions of pH and temperature on the gelation time. At low pH (3 < pH < 7), the gelation time decreased by decrease of pH while at CaCl₂ concentration of 3750–11250 ppm and at 7 < pH < 11, the gelation time increased with the increase of pH. It was found that temperature was the most effective parameter to control the gelation time.     

Cathode catalysts degradation mechanism from liquid electrolyte to membrane electrode assembly

Single-cell and half-cell degradation test procedures were evaluated for carbon-supported Pt/C, PtCo/C and PtNi/C catalysts. Half-cell analyses were employed to understand the effect of the number of cycles and of the scan rate over the cathode catalysts degradation under potential cycling from 0.6 to 1.2 V. The data suggested a time-dependent degradation for all three catalytic systems. Single-cell measurements were used to evaluate the impact of catalyst degradation on fuel cell performance. The measurements in both setups showed similar ECSA and ORR mass activity losses. Specific degradation mechanisms related to Pt dissolution, Pt agglomeration, and transitional metal leaching were quantified and correlated with performance losses.     

Generation of entanglement via atomic coherence in a two-mode three-level cascade atomic system

The generation of continuous variable entanglement via atomic coherence in a two-mode three-level cascade atomic system is discussed according to the entanglement criterion proposed by Duan et al. [Phys. Rev. Lett. 84, 2722 (2000)]. Atomic coherence between the top and bottom levels is induced with two photons of a strong external pump field. It shows that entanglement for the two-mode field in the cavity can be generated under certain conditions. Moreover, by means of the input-output theory, we show that the two-mode entanglement could also be approached at the output.