Dispersion characterization in layered double hydroxide/Nylon 66 nanocomposites using FIB imaging

Layered double hydroxides (LDHs), a newly emerging 2D host material, consist of cationic brucite-like layers and exchangeable interlayer anions. In this work, the morphology and dispersion of LDH particles in LDH/Nylon 66 (salt) nanocomposites has been investigated using focused ion beam (FIB) techniques, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The FIB images show that LDHs are present in the polymer phase dispersed to different degrees, with partial intercalation, exfoliation, and aggregation all being observed. The most even dispersion was achieved in nanocomposites with the lowest loading (0.5 wt % LDH). Residual tactoids and agglomerates were most common in the samples made with the highest concentration of LDHs studied here (5 wt %). The dispersion observed using FIB was consistent with TEM and XRD analysis, yet this technique had significant benefits in terms of time and simplicity over these “conventional” technologies. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Liquid chromatography combined with tandem mass spectrometry for the confirmation of sarafloxacin in catfish tissue

A specific chromatographic LC/MS/MS assay is described for the confirmatory identification of residues of sarafloxacin, an arylfluoroquinolone antibacterial agent, in catfish tissue. This confirmatory method takes advantage of the specificity provided by sample preparation, liquid chromatography, and tandem mass spectrometry. This kind of multidimensional analysis is commonly used in environmental, pharmacokinetic, residue, and other studies. However, we demonstrate the addition of a previously unreported criterion, the use of ion ratio ranges from the tandem mass spectrometry (MS/MS) experiment as an aid in confirmation. Using the described method, we were able to achieve MS/MS product ion ratios with <7% variation during 1 day of analysis for over 25 injections. We believe the addition of this criterion will increase the scientific certainty of the confirmatory method.     

Suicide Attempt Self-Injury Interview (SASII): Development, reliability, and validity of a scale to assess suicide attempts and intentional self-injury.

The authors describe the development of the Suicide Attempt Self-Injury Interview (SASII), an instrument designed to assess the factors involved in nonfatal suicide attempts and intentional self-injury. Using 4 cohorts of participants, authors generated SASII items and evaluated them with factor and content analyses and internal consistency statistics. The final measure was assessed for reliability and validity with collateral measures. The SASII assesses variables related to method, lethality and impulsivity of the act, likelihood of rescue, suicide intent or ambivalence and other motivations, consequences, and habitual self-injury. The SASII was found to have very good interrater reliability and adequate validity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confidence Intervals for Reliability and Quantile Functions With Application to NASA Space Flight Data

This paper considers the construction of confidence intervals for a cumulative distribution function F(z), and its inverse quantile function F^-1(u), at some fixed points z, and u on the basis of an i.i.d. sample Xlowbar={X_i}_i=1 ⁿ, where n is relatively small. The sample is modeled as having a flexible, generalized gamma distribution with all three parameters being unknown. Hence, the technique can be considered as an alternative to nonparametric confidence intervals, when X is a continuous random variable. The confidence intervals are constructed on the basis of Jeffreys noninformative prior. Performance of the resulting confidence intervals is studied via Monte Carlo simulations, and compared to the performance of nonparametric confidence intervals based on binomial proportion. It is demonstrated that the confidence intervals are robust; when data comes from Poisson or geometric distributions, confidence intervals based on a generalized gamma distribution outperform nonparametric confidence intervals. The theory is applied to the assessment of the reliability of the Pad Hypergol Servicing System of the Shuttle Orbiter     

The design and use of low-cost heat flux plates for the measurement of building heat transfer rates

A review of some published building heat flux measurement plates shows them to be difficult and expensive to manufacture. Then a simple made, low-cost design is described which is suitable for production in both small numbers or quantity.     

Erratum to: Fe Oxides on Ag Surfaces: Structure and Reactivity

Topics in Catalysis -     

Metallurgical assessment of a hypereutectic aluminum–silicon P/M alloy

The objective of this study was to perform a comprehensive assessment on the press-and-sinter P/M processing of a novel hypereutectic aluminum–silicon alloy known as Alumix-231 (Al–15Si–2.5Cu–0.5Mg). As this patented commercial product is relatively new, the amount of scientific data available in the literature is highly limited. To address this issue sintered products were evaluated by analyzing the density before and after sintering, apparent hardness, microstructural features, tensile properties, and finally the response to heat treatment. It was determined that the optimum processing route for Alumix-231 involved compaction at a pressure of 600 MPa followed by de-lubrication at 400 °C for 20 min before being sintered at 560 °C for a period of 60 min. The optimum heat treatment involved solutionizing the samples at 520 °C for 1 h, followed by water quenching, and artificially aging the samples at 160 °C for 8 h. The system proved highly responsive to this manner of processing attaining a sintered density on the order of 98% of theoretical and a UTS of 330 MPa. Based on a combination of DSC, XRD, and EPMA analyses it was concluded that θ-type phases were the dominate precipitates formed during heat treatment.     

The impact of growing miscanthus for biomass on farmland bird populations

Miscanthus is a newly introduced crop grown primarily to produce biomass for energy production and the area grown in the UK is anticipated to increase. Major differences in crop management from conventional arable crops have led to speculation that miscanthus may also have effects on farmland biodiversity. Six miscanthus fields were paired with six of a conventional crop, winter wheat, and bird diversity and abundance were compared in winter and during the breeding season along with potential food sources. Miscanthus fields had a greater abundance and diversity of birds than did wheat in winter and summer. In winter, the greater numbers of birds in miscanthus fields were probably attracted by the shelter provided by the crop and by the abundance of non-crop plants. During the breeding season, the abundance of non-crop plants in miscanthus fields, and greater numbers of insects associated with these plants, provided food resources. However, the miscanthus crop plants provided less insect food than wheat crop plants. Changes in crop structure during the breeding season influenced the breeding birds. The results from this study suggested that an increase in the area of miscanthus grown in the UK may have temporary benefits for farmland bird populations during establishment. These benefits are likely to diminish with age of crop and as crop management improves with experience. Management for wildlife will be required to maintain the diversity of features attractive to birds because many of these will be lost if miscanthus is managed solely to maximise crop yields.     

Threshold current reduction in InGaN MQW laser diode withλ/4 air/semiconductor Bragg reflectors

A 13% reduction in the threshold current density of InGaN laser diodes is demonstrated upon the introduction of two 5λ/4 air/nitride Bragg reflectors. These are defined at one end of the laser cavity by means of focused ion beam etching     

Case study: an investigation into the cause of `error rate drift'

During product development some Hewlett-Packard DDS tape drives experienced a gradual increase in their uncorrected error rate when running a particular operating test at low humidity. This was known as `error rate drift'. A combination of system-level testing, signal processing, and atomic force microscopy showed that the degradation was caused by contamination on the surface of the heads. The `stain' thickness increased each time tape was reused, resulting in progressive attenuation of the readback signal amplitude. Using time-of-flight secondary ion mass spectroscopy the contaminant was identified as inorganic Fe, Si and Al, transferred from the media.