A saddle field ion source of spherical configuration for etching and thinning applications

The construction is described of a saddle field ion source with its axis of symmetry coincident with the centre of the ion beam. The source consists of a spherical cathode enclosing an annular anode. Source current-source voltage and source current-ion beam current characteristics are given for argon, nitrogen, helium and hydrogen. A typical energy distribution curve is shown for argon at 6 kV at 2 × 10^?4 torr, the beam energy is 0.85 of the anode potential and the half width is about 250 V. The beam density is about 1 mA cm^?2, and the beam divergence 4°. Applications of cylindrical and spherical sources are described to ion beam machining, thinning and surface analysis.     

Getting worse: Psychotherapy or no treatment—the jury should still be out.

It has been contended that patients receiving psychotherapy show significantly higher rates of deterioration than similar patients who receive no treatment. It has further been suggested that psychotherapy causes harm to some of those receiving it. These concerns are widely circulated and are likely to influence decision making at this critical time for the mental health professions. Relevant studies are reviewed with particular attention to characteristics of design. It is concluded that few studies allow for meaningful comparisons between experimental and control groups. In studies permitting such comparisons, there is no significant evidence of greater deterioration among the experimental groups. Alternative hypotheses consistent with these conclusions are presented, each with different implications for reducing the incidence of deterioration. The need for more and better research is underscored. (3 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tunable metallic-like conductivity in microbial nanowire networks

Electronic nanostructures made from natural amino acids are attractive because of their relatively low cost, facile processing and absence of toxicity. However, most materials derived from natural amino acids are electronically insulating. Here, we report metallic-like conductivity in films of the bacterium Geobacter sulfurreducens and also in pilin nanofilaments (known as microbial nanowires) extracted from these bacteria. These materials have electronic conductivities of ～5?mS?cm(-1), which are comparable to those of synthetic metallic nanostructures. They can also conduct over distances on the centimetre scale, which is thousands of times the size of a bacterium. Moreover, the conductivity of the biofilm can be tuned by regulating gene expression, and also by varying the gate voltage in a transistor configuration. The conductivity of the nanofilaments has a temperature dependence similar to that of a disordered metal, and the conductivity could be increased by processing.     

"Personality and risk for Alzheimer's disease in adults 72 years of age and older: A 6-year follow-up": Correction to Duberstein et al. (2010).

Reports an error in "Personality and risk for Alzheimer's disease in adults 72 years of age and older: A 6-year follow-up" by Paul R. Duberstein, Benjamin P. Chapman, Hilary A. Tindle, Kaycee M. Sink, Patricia Bamonti, John Robbins, Anthony F. Jerant and Peter Franks (Psychology and Aging, , , np). This article contains an error in the Discussion, under the Implications, Caveats, Future Directions heading. The third paragraph includes sentences that should have been removed, as they are a variation on similar text immediately following. The sentences that should have been removed are presented in the erratum. (The following abstract of the original article appeared in record 2010-22067-001.) We conducted secondary analyses to determine the relationship between longstanding personality traits and risk for Alzheimer's disease (AD) among 767 participants 72 years of age or older who were followed for more than 6 years. Personality was assessed with the NEO-FFI. We hypothesized that elevated Neuroticism, lower Openness, and lower Conscientiousness would be independently associated with risk of AD. Hypotheses were supported. The finding that AD risk is associated with elevated Neuroticism and lower Conscientiousness can be added to the accumulating literature documenting the pathogenic effects of these two traits. The link between lower Openness and AD risk is consistent with recent findings on cognitive activity and AD risk. Findings have implications for prevention research and for the conceptualization of the etiology of AD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The influence of the density of a gas-solid fluidized bed on the dry dense medium separation of lump iron ore

A gas-solid fluidized bed was used for dry dense medium separation of lump iron ore particles based on their floating and sinking in the fluidized bed. The density of the bed was adjusted to different values using mixtures of zircon sand and iron powder as the fluidized media. Float-sink experiments using 30 mm diameter density adjusted spheres in the range of 2100-4500 kg/m³ in density increments of 100 kg/m³ were carried out to determine the partition curves, the density of the bed and the probable error (Ep). It was found that the density could be adjusted in the range of 2500-4200 kg/m³, when the bulk volume fraction of iron powder and the fluidizing air velocity were varied. The Ep values were less than or equal to 0.05, if suitable fluidizing air velocities were chosen. The density of the bed determined using the spheres floating-sinking corresponds to that measured using the height of the fluidized bed. The float-sink performance of lump iron ore particles in the size range of +25-31.5 mm agrees well with the spheres’ float-sink performance. The partition curves, separation density and the Ep values were determined for the lump iron ore particles. The Ep value for the ore particle separation was around 0.03. The theoretical Fe-grade recovery (washability) curve for the ore was determined for separation densities between 2500 and 4200 kg/m³ from the density distribution and Fe content of the lump iron ore particles. The actual Fe-grade and recovery were calculated from the partition curves of the ore particle separation and compared to the theoretical maximum obtainable Fe-grade and recovery.     

Deep Anomaly Detection on Tennessee Eastman Process Data

This paper provides the first comprehensive evaluation and analysis of modern (deep-learning-based) unsupervised anomaly detection methods for chemical process data. We focus on the Tennessee Eastman process dataset, a standard litmus test to benchmark anomaly detection methods for nearly three decades. Our extensive study will facilitate choosing appropriate anomaly detection methods in industrial applications. From the benchmark, we conclude that reconstruction-based methods are the methods of choice, followed by generative and forecasting-based methods.     

Aqueous and Nonaqueous Colloidal Processing of Difficult‐to‐Densify Ceramics: Suspension Rheology and Particle Packing

Aqueous and nonaqueous colloidal processing of zirconium diboride (ZrB₂) and boron carbide (B₄C) has been investigated. The aqueous and nonaqueous ZrB₂ and B₄C suspension formulations have been optimized. The suspensions were cast into green bodies using slip casting. The correlation between the state of dispersion with the rheological properties of the suspensions and the resulting packing density was observed in both aqueous and nonaqueous processing. The attractive interactions between powder particles in water were difficult to overcome with electrical double layer or electrosteric repulsion. Reasonably low viscosity aqueous ZrB₂ suspensions up to 45 vol% solids could be prepared. It was not possible to produce low viscosity (viscosity below 1 Pa·s at shear rate of 100 s^?1) aqueous B₄C suspensions with solid content above 30 vol%. Slip casting of the weakly aggregated ZrB₂ suspensions resulted in low packing densities (~55% relative density) of the green bodies. On the other hand, dispersion of powder particles in nonaqueous media (cyclohexane and dodecane) enabled suspensions with lower viscosities and a higher maximum solid concentration (up to 50 vol%) to be prepared. The well‐dispersed nonaqueous suspensions promoted an efficient particle packing, resulting in higher green densities (64% and 62% relative density for ZrB₂ and B₄C, respectively) compared to aqueous processing. The significantly high green densities are promising to allow densification of the materials at lower sintering temperature.     

Storage of chicken breast meat in paper coated with different types of hydrophobic agents

Chicken meat is well known for its high nutritional value. Its shelf life is short, due to the pronounced perishability, even under refrigeration. Paper bags are usually used as packaging materials, due to their biodegradability. The main negative aspect concerning paper is its high porosity and low moisture barrier. In this regard, it has to be coated/modified with efficient moisture barrier materials. The storage of chicken breast meat wrapped in four types of paper-based materials currently in use in Romania (RO), Italy (IT), Spain (SP) and Slovenia (SLO) is reported. RO and IT are paper coated with polyethylene (PE) film, SP is waxed paper, and SLO is paper modified with hydrophobized starch. The influence of the coating film on the organoleptical, biochemical and microbiological characteristics of the chicken breast meat stored at 4°C was the aim of the study. The mathematical modelling revealed two aspects: (1) the stability period in which the meat safe for consumption is in the range 1.92–2.18 days in the case of all paper types, and (2) cadaverine, the amine generated by protein degradation, is a less sensitive indicator of the meat alteration than microbial growth. The papers coated with PE (RO and IT samples) and with hydrophobized starch (SLO paper) were packaging materials more efficient that the waxed paper (SP sample). The polyethylene film reduced the conversion of putrescine into spermidine in a higher extent than wax.     

Cracking during freeze-drying in dense freeze cast ceramics: Role of drying rate

Cracks can form during the freeze-drying of freeze cast ceramic suspensions while attempting to produce dense ceramics. The suspensions contain alumina particles dispersed in cyclohexane. The rate of drying is controlled by the pressure and temperature during drying (slow drying at atmospheric pressure and −15°C and fast drying under vacuum while the temperature slowly increases from −80°C to room temperature). X-Ray micro-computed tomography was used to characterize internal crack formation. Cracks were found to occur during freeze-drying rather than during freezing. Both slow and fast drying produced cracks, although two different morphologies were observed. Mechanistic models are proposed for the formation of both types of cracks. The rate of freezing was found to influence the formation of cracks. Slow freezing tended to reduce the formation of drying cracks because the slower freezing produced a more heterogeneous distribution of particles and porous regions, which tends to allow stress to be relieved by opening up existing pores rather than forming cracks in the more homogeneous fast frozen bodies.