Polypropylene/carbon nanotube nanocomposite fibers: Process–morphology–property relationships

This study is focused on aligning carbon nanotubes in polypropylene matrix by melt spinning. Two different weight percentages (0.5% and 1.0%) of nanotubes were used for the synthesis of the nanocomposite fibers. The effect of the nanotubes on the crystallization and mechanical behavior of polypropylene as well as the effect of draw ratio on the nanocomposite morphology and properties is also discussed. Correlation of fiber morphology and nanotube alignment was done using differential scanning calorimetry, wide‐angle X‐ray diffraction, and transmission electron microscopy. Significant improvement in tensile modulus and tensile strength were observed, which is characteristic of a highly aligned nanotube system. A substantial vincrease in the onset of decomposition was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3844–3850, 2007     

Liquid sampling-atmospheric pressure glow discharge ionization source for elemental mass spectrometry

A new, low power ionization source for elemental MS analysis of aqueous solutions is described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) operates by a process wherein the surface of the liquid emanating from a 75 μm i.d. glass capillary acts as the cathode of the direct current glow discharge. Analyte-containing solutions at a flow rate of 100 μL min(-1) are vaporized by the passage of current, yielding gas phase solutes that are subsequently ionized in the <5 W (maximum of 60 mA and 500 V), ~1 mm(3) volume, plasma. The LS-APGD is mounted in place of the normal electrospray ionization source of a Thermo Scientific Exactive Orbitrap mass spectrometer system without any other modifications. Basic operating characteristics are described, including the role of discharge power on mass spectral composition, the ability to obtain ultrahigh resolution elemental isotopic patterns, and demonstration of potential limits of detection based on the injection of aliquots of multielement standards (S/N > 1000 for 5 ng mL(-1) Cs). While much optimization remains, it is believed that the LS-APGD ion source may present a practical alternative to high-powered (>1 kW) plasma sources typically employed in elemental mass spectrometry, particularly for those cases where costs, operational overhead, simplicity, or integrated elemental/molecular analysis considerations are important.     

Visual marking and visual change.

Five experiments investigated the types of changes that disrupt the preview effect--the benefit gained in difficult search tasks from presenting some distractors earlier in time. A shape change with or without an overall luminance change at the location of an old item was found to disrupt the preview effect, whereas an equivalent luminance change alone or an isoluminant color change was not disruptive. Results suggest that (a) relatively low-level visual changes may not be sufficient to abolish the benefit, (b) the benefit most likely occurs through inhibition applied to locations within a location master map, and (c) inhibition need not be applied to surface features of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Think Phased Implementation for Successful Data Warehousing

Industry watchers have noted that the success rate of data warehouse (DW) implementations has not been exemplary. It is believed that over 50 percent of DW implementations fail to achieve their stated goals. However, there are things that executives can do to improve their chance of success. Like other forms of organizational change, the DW implementation process follows a three-phased pattern of evolution. Clear recognition by management of the phased logic of DW implementation, and the differing role of critical implementation factors (CIFs) in each of the phases, can enhance the probability of success. This article presents a framework that helps executives visualize how CIFs can be customized and embedded in each phase of the DW implementation process.     

System identification of the human thermoregulatory system using continuous-time block-oriented predictive modeling

This article presents preliminary results of a new research program for identifying predictive models for human thermoregulatory (HT) response using only an individual's attributes and their physical property data to build the model. This program is being developed in phases and this article presents results of the first phase. This initial phase demonstrates that the proposed semi-empirical (i.e., gray-box), continuous-time, block-oriented modeling (BOM) approach [Rollins, et al. 2003. A continuous time nonlinear dynamic predictive modeling method for Hammerstein processes. Industrial and Engineering Chemistry Research 42, 861-872; Bhandari and Rollins, 2003. A continuous-time MIMO Wiener modeling method. Industrial and Engineering Chemistry Research 42, 5583-5595.] is capable of accurately predicting HT response. This ability is demonstrated using real data from literature [Hardy and Stolwijck, 1966. Partitional calorimetric studies of man during exposures to thermal transients. Journal of Applied Physiology 21(6), 1799-1806.] and computer generated data from a HT semi-theoretical model with qualitatively accurate physiological behavior [Wissler, 1963. An analysis of factors affecting temperature levels in the nude human. Temperature—its Measurement and Control in Science and Industry 3(3), 603-612; Wissler, 1964. Mathematical model of the human thermal system. Bulletin of Mathematical Biophysics 26, 147-166.]. A critical strength of the proposed gray-box BOM approach is the use of physically interpretable structures and model coefficients. This article discusses how this strength can be exploited to identify a predictive HT response model for an individual without using environmental chamber data of the individual.     

Grain mineral concentrations and yield of wheat grown under organic and conventional management

On the low‐P soils in southeastern Australia, organic crops differ from conventional ones primarily in the use of relatively insoluble, as opposed to soluble, P fertilisers and in the non‐use of herbicides. As organic management, particularly elimination of soluble fertilisers, is often claimed to enhance grain mineral concentrations, we examined grain from wheat on paired organic and conventional farms in two sets of experiments: (1) four pairs of commercial crops (1991–1993); and (2) fertiliser experiments on one farm pair where nil fertiliser was compared with 40 kg ha^?1 of P as either relatively insoluble reactive phosphate rock or more soluble superphosphate (1991 and 1992). All wheat was grown following a 2–6 year legume‐based pasture phase. Both conventional management and the superphosphate treatment greatly increased yields but reduced colonisation by mycorrhizal fungi. While only minor variations occurred in grain N, K, Mg, Ca, S and Fe concentrations, conventional grain had lower Zn and Cu but higher Mn and P than organic grain. These differences were ascribed to: soluble P fertilisers increasing P uptake but reducing mycorrhizal colonisation and thereby reducing Zn uptake and enhancing Mn uptake; dilution of Cu in heavier crops; and past lime applications on the organic farm decreasing Mn availability. These variations in grain minerals had nutritional implications primarily favouring the organic grain; however, organic management and, specifically, elimination of soluble fertilisers did not induce dramatic increases in grain mineral concentrations. In addition, organic management was coupled with yield reductions of 17–84 per cent due to P limitation and weeds. The impact of large regional variations in the characteristics of organic and conventional systems on the general applicability of the results from this study and other similar studies is discussed. Copyright © 2004 Society of Chemical Industry     

Fetal and maternal plasma electrolytes, blood gases, and pH in dairy cows during late gestation.

Sodium, potassium, and chloride were determined in fetal and maternal plasma of six cows between 208 and 269 days of gestation. Blood pH and partial pressures of oxygen and carbon dioxide also were measured in samples collected from the jugular vein of the cow and the caudal aorta and vena cava of the fetus. Concentration of chloride in fetal plasma was generally lower than the corresponding maternal value, and fetal potassium was greater than maternal. Potassium of fetal plasma increased towards term. Sodium concentrations were not significantly different between fetal and maternal plasms. Once fetal and maternal pH and blood gas tensions had stabilized after surgery, there was little change until shortly before delivery. In the last 24 h before calving maternal partial pressure of oxygen was high and fetal blood pH was low.     

A Quantitative Measure to Evaluate Competing Designs for Non‐linear Dynamic Process Identification

The strategy for the collection of information (i.e., data) for model development is called experimental design. Optimal design seeks to maximize the information content under constraints of time and sampling. In the system identification literature the dominant strategy has been the method of pseudo random sequences (PRS). However, this work demonstrates that statistical design of experiments (SDOE) can provide greater information content as quantitatively measured by the D‐optimal criterion.     

In utero varicella-zoster infections

In utero varicella-zoster infections, though infrequent, may have significant consequences for the affected infant depending on the gestational timing of the infection. We present a case of infantile zoster in a 5-month-old boy after maternal varicella infection. Also, we review the three major disorders resulting from in utero infection with respect to severity and management.