Surface characterization and catalytic properties of La1−x -Sr x CoO3

The surface chemical states of the perovskite-type compounds, strontium doped lanthanum cobalt oxides (La_1?x Sr _x CoO₃), have been investigated using X-ray photoelectron spectroscopy (XPS). Catalytic oxidations of both methane and CO have also been investigated using flow methods. The chemical composition of the surface of La_1?x Sr _x CoO₃ was very different from that in the bulk, which was measured by X-ray fluorescence spectroscopy (XRFS). The catalytic activity of La_1?x Sr _x CoO₃ increased with an increase in the quantity of cobalt atoms on the surface.     

New method for selective growth of diamonds by microwave plasma chemical vapour deposition

Selective nucleation and deposition of diamonds were achieved on an SiO₂-patterned Si substrate. The substrate was pre-treated with an electric field in plasma to introduce diamond nuclei. This treatment did not affect the SiO₂ area. Consequently, diamonds grew only on the area where Si was exposed under the conventional conditions of diamond growth. The maximum nucleation density on the area of SiO₂was about 5 × 10⁷ cm⁻². The ratio of the selectivity was 2 × 10² or higher. This process will be useful and very promising for manufacturing diamond electronic devices.     

W-type hexaferrite nanoparticles: A consideration for microwave attenuation at wide frequency band of 0.5-10 GHz

The static and dynamic magnetic properties of W-type hexaferrites are tuned to meet the requirements of wide band frequencies for attenuation of electromagnetic interference and microwave absorptions purposes. For this purpose, the W-type hexaferrite of entirely new composition of BaCoZnFe_16−2yAl_yCe_yO₂₇ (y = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) has been synthesized by the chemical co-precipitation. The material is characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The complex permittivity (?_r = ?′ − j?″) and permeability (μ_r = μ′ − jμ″) spectra are determined using Vector Network Analyzer (VNA) in a range from 0.5 GHz to 10 GHz. During this study, it is noticeable that the Al³⁺ and Ce³⁺ ions have considerable effect on the shape of the nanoparticles. Samples having Al-Ce contents y = 0.2 and y = 0.4 showed large values for magnetization (70.5 emu/g) and remanent magnetization (32.9 emu/g). In addition, more than 99% absorption (>−20 dB) is noted for this sample composition. Based on these results it is concluded that the microwave absorption characteristics of these compounds can be tuned for the required frequency by varying the thickness of the absorber. Due to this reason, potential employment of the synthesized nanoparticles for absorption of electromagnetic radiations at wide frequency band of 0.5-10 GHz has been proposed.     

Interfacing digitiezed Disa anemometer output to an Apple II computer

For measuring the velocities in a fluctuating fluid flow, the new Disa 56C00 multichannel constant-temperature anemometer system can be used with the 56N00 signal analysis equipment to provide a digital output of mean, root mean square or correlation values. A simple interface arrangement and appropriate software control for reading data directly into an Apple II computer are described. With these the subsequent calculation of derived parameters, such as displacement and momentum thickness of boundary layers and turbulence intensity, can be quickly and easily completed.     

XPS and IR study of electrochemically or chemically redoped poly(3-methylthienylene) films

XPS (X-ray photoemission spectroscopy) and IR (infrared) analyses of poly(3-methylthienylene) films, electrochemically or chemically redoped0 with various chemical species at varying doping levels, have been investigated. On the basis of these results, the major chemical species of dopants have been identified. As a results, the dopant content was determined and the poly(3-methylthienylene) films were classified as light or heavy by doping level. The conductivity ranged from about 10^?12 to 10₂ S cm^?1 for all the films investigated. The conductivity and the activation energy of conduction for the heavily-doped films vary as a function of the dopant content, independent of the different chemical species of dopants. In particular, a sudden change is observed in the dependence of activation energy on dopant content. This sudden change may be associated with the semi-conductor-metal transition. Furthermore, it is shown that the specific absorption bands in the infrared are induced by the doping, intensified with increasing dopant uptake and accompanied by an increase in conductivity.     

Persistence and partitioning of eight selected pharmaceuticals in the aquatic environment: Laboratory photolysis, biodegradation, and sorption experiments

We selected eight pharmaceuticals with relatively high potential ecological risk and high consumption—namely, acetaminophen, atenolol, carbamazepine, ibuprofen, ifenprodil, indomethacin, mefenamic acid, and propranolol—and conducted laboratory experiments to examine the persistence and partitioning of these compounds in the aquatic environment. In the results of batch sunlight photolysis experiments, three out of eight pharmaceuticals—propranolol, indomethacin, and ifenprodil—were relatively easily photodegraded (i.e., half-life < 24 h), whereas the other five pharmaceuticals were relatively stable against sunlight. The results of batch biodegradation experiments using river water suggested relatively slow biodegradation (i.e., half-life > 24 h) for all eight pharmaceuticals, but the rate constant was dependent on sampling site and time. Batch sorption experiments were also conducted to determine the sorption coefficients to river sediments and a model soil sample. The determined coefficients (K_d values) were much higher for three amines (atenolol, ifenprodil, and propranolol) than for neutral compounds or carboxylic acids; the K_d values of the amines were comparable to those of a four-ring polycyclic aromatic hydrocarbon (PAH) pyrene. The coefficients were also higher for sediment/soil with higher organic content, and the organic carbon-based sorption coefficient (log K_oc) showed a poor linear correlation with the octanol-water distribution coefficient (log D_ow) at neutral pH. These results suggest other sorption mechanisms—such as electrochemical affinity, in addition to hydrophobic interaction—play an important role in sorption to sediment/soil at neutral pH.     

Analysis of human error in nursing care

Analysis of reports about incidental and accidental events in nursing care were made using a reliability engineering method. Unnatural working hours, such as evening duty, night duty falling next to a holiday, two consecutive night-duty shifts, and two consecutive evening-duty shifts were major factors in the occurrence of errors. In a mixed-division ward (a ward containing patients belonging to different divisions), rule-based errors happened more frequently than in a single-division ward. Also, less experienced nursing staffs made errors more frequently than experienced nursing staffs.