Thermomechanical and thermochemical stability of HfSiO4 for environmental barrier coating applications

Thermomechanical and thermochemical stability of hafnon (HfSiO₄) was evaluated for application as an environmental barrier coating (EBC) candidate for SiC/SiC CMCs. High-temperature X-ray diffraction (XRD) analysis showed that hafnon has an excellent coefficient of thermal expansion (CTE) match with SiC as well as minimal CTE anisotropy, which supports hafnon as an EBC candidate. Alternatively, high-velocity water vapor testing at 1,200-1,400°C showed large amounts of silica depletion from chemical reaction at all velocities and excessive material erosion at steam velocities greater than 190 m/s. HfSiO₄ is therefore not suitable as an EBC for turbine applications due to insufficient thermochemical stability in water vapor-containing combustion environments.     

Chirp-pulse-compression three-dimensional lidar imager with fiber optics

A coherent three-dimensional (angle-angle-range) lidar imager using a master-oscillator-power-amplifier concept and operating at a wavelength of 1.5 microm with chirp-pulse compression is described. A fiber-optic delay line in the local oscillator path enables a single continuous-wave semiconductor laser source with a modulated drive waveform to generate both the constant-frequency local oscillator and the frequency chirp. A portion of this chirp is gated out and amplified by a two-stage fiber amplifier. The digitized return signal was compressed by cross correlating it with a sample of the outgoing pulse. In this way a 350-ns, 10-microJ pulse with a 250-MHz frequency sweep is compressed to a width of approximately 8 ns. With a 25-mm output aperture, the lidar has been used to produce three-dimensional images of hard targets out to a range of approximately 2 km with near-diffraction-limited angular resolution and submeter range resolution.     

Regulation of macrophage adhesion and migration by Rho GTP-binding proteins

The Rho family proteins Rac and Rho are believed to be key regulators of cell migration through their effects on the cytoskeleton and cell adhesion. However, recent studies in macrophages indicate that they are not always essential for migration, although they do affect cell shape and adhesion.     

Characterization of ADN and ADN‐Based Propellants

Ammonium dinitramide (ADN), NH₄N(NO₂)₂ is being considered as one of the potential new energetic oxidizers for composite propellants. In this study, ADN crystals, prills and two ADN‐based propellants having different relative amounts of ingredients were characterized. The concentration of the crystals and the prills samples was determined using ion chromatography. The thermal behavior of the crystals, prills and propellants was studied using DSC, simultaneous TG‐DTA‐FTIR‐MS, ARC (accelerating rate calorimeter), HFC (heat flux calorimeter) and INC (isothermal nanocalorimeter). Decomposition of ADN was observed from all of the samples at temperatures above the melting point of ADN (~ 92 °C). Formation of N₂O, NO₂, H₂O, CO₂, CO, N₂ and NO was detected during the ADN decomposition. The thermal stability of the ADN samples at temperatures below the melting point of ADN was studied. Early solid decomposition of ADN, which generates N₂O and H₂O, was observed at 60 °C. Electrostatic discharge (ESD) and impact sensitivity of the ADN samples were determined. The crystals and prills are sensitive to impact, while the two propellants are relatively less ESD and impact sensitive.     

Religiously sensitive rational emotive behavior therapy: Theory, techniques, and brief excerpts from a case.

Rational emotive behavior therapy's (REBT's) methods for fostering change, such as disputation of irrational beliefs, are similar to the kinds of activities one may expect to encounter in many organized religions. REBT also bears a strong theoretical affinity with some religions because of its preferred therapeutic goal of helping clients examine and change their beliefs. Furthermore, the formal religious tenets and traditions to which many clients adhere will usually include doctrinal material that is highly congruent with REBT's theory of change. Such belief-oriented material may be enlisted during REBT to help religious clients evaluate and change their self-defeating, irrational beliefs. A case that integrates religious belief with REBT is presented. Finally, the authors conclude with a brief summary of preliminary outcome research regarding the efficacy of this approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intermediate care, possibilities, requirements and solutions

The inadequate supply of intensive care facilities has focused interest on intermediate care as a means of bridging the gulf between the level of support available in the intensive care unit and the general ward. However, few hospitals have developed intermediate care, in the form of high-dependency care units, and little information exists concerning the use or potential of such areas. Therefore, this review proposes to cover the definition of intermediate care and to discuss some of the possible reasons why intermediate care is now believed necessary. The capabilities of intermediate care for selected groups of patients and the treatment modalities offered are described. The present provision of high-dependency care in the United Kingdom is discussed and the methods for estimating the required size of a high-dependency unit are outlined. The impact of a high-dependency unit on the workload of the intensive care unit and the potential cost saving of managing such patients in an intermediate care area are illustrated.     

Radiology of skeletal tuberculosis

The process of hepatic fibrosis, and the changes in contents of hepatic hyproxyproline (HYP) and serum procollagen type III peptide (PIIINP) were examined in two rat models for hepatic fibrosis, i.e. bile duct ligation/scission (BDL/s)- and dimethylnitrosamine (DMN)-induced models. In addition, an expression of type III collagen mRNA in the liver of BDL/s model was also examined. In BDL/s model, hepatic fibrosis started at 2 weeks after operation (WAO) and cirrhosis with prominent bile duct hyperplasia was detected at and after 5 WAO. Serum PIIINP content measured using a modified double armed inhibition enzyme-linked immunosorbent assay (ELISA) method proposed by us started to increase at 1 WAO and continued to increase thereafter. Hepatic HYP content measured colorimetrically started to increase at 3 WAO and it continued to increase until 7 WAO. An expression of type III collagen mRNA in the liver was enhanced at and after 2 WAO, especially at 4 and 5 WAO. In DMN model, marked hepatic fibrosis was detected at 1 week after the last DMN administration (WAA), and the degree of fibrosis was apparently reduced at 4 WAA. Serum PIIINP content prominently increased at 1 WAA and decreased at and after 3 WAA. Hepatic HYP content showed a marked increase at 1 WAA and decreased thereafter. The present results indicated that the sequences of hepatic fibrosis, hepatic HYP content and serum PIIINP content were well correlated with each other in both BDL/s and DMN models. In conclusion, ELISA system for the detection of serum PIINP content is considered to be reliable method for assessment of cirrhotic liver, and the present two rat models for liver fibrosis/cirrhosis seems to be a good tool for researching antifibrotic agents.     

Multi-loop control for quasi-resonant converters

A multiloop control scheme for quasi-resonant converters (QRCs) is described. Like current-mode control for pulse width modulation (PWM) converters, this control offers excellent transient response and replaces the voltage-controlled oscillator (VCO) with a simple comparator. In this method, referred to as current-sense frequency modulation (CSFM), a signal proportional to the output-inductor current is compared with an error voltage signal to modulate the switching frequency. The control can be applied to either zero-voltage-switched (ZVS) or zero-current-switched (ZCS) QRCs. Computer simulation is method applied to a ZCS buck QRC. A circuit implementation is presented that allows multiloop control to be used on circuits switching up to 10 MHz. This circuit requires few components and produces clean control waveforms. Experimental results are presented for zero-current flyback and zero-voltage buck QRCs, operating at up to 7 MHz. Good small-signal characteristics have been obtained     

Religiously sensitive rational emotive behavior therapy: Elegant solutions and ethical risks.

Rational emotive behavior therapy (REBT) can be an elegant treatment modality for explicitly religious clients. This is true in spite of the traditional antireligious stance of Albert Ellis. In this article, the authors summarize the evolution of Ellis's views on religion and mental health, consider potential ethical dilemmas caused by utilizing REBT with religious clients, and recommend strategies for reducing violation of ethical and specialty guidelines in work with religious clients. The authors conclude by proposing a general model for religiously sensitive psychotherapy, which may serve to undergird theorizing and research on the application of REBT and other treatment approaches to religious clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)