Some aspects of deformation behavior of coarse multiphase metallic materials

The deformation behavior of several single-and two-phase coarse microstructures has been examined using microhardness measurements. It has been found that the strength response of a coarse phase in isolation is distinctly different from its response when it exists in a two-phase system. The second phase alters the mechanical state of the first one andvice versa even in the plastically undeformed condition. This phenomenon is explained in terms of the existence of an appreciable amount of residual stresses in two-phase coarse microstructures. These stresses primarily arise due to the difference in thermal expansion coefficients of the phases. The influence of elastic stress field on microhardness response is shown with a new type of experiment to support the proposed explanation. The present results question the existing expressions for deformation modeling of multiphase materials because of the uncertainties in the estimation of the average strength of the phases in a two-phase system.     

A PBS2 homologue from Debaryomyces hansenii shows a differential effect on calcofluor and polymyxin B sensitivity in Saccharomyces cerevisiae

The PBS2 gene encodes a MAP kinase kinase that plays a pivotal role in osmosensing signal-transduction pathway in the yeast Saccharomyces cerevisiae. Mutation in the PBS2 gene has a pleotropic effect. Besides being osmosensitive, pbs2 mutants show altered sensitivity to polymyxin B and calcofluor. Recent studies revealed that Pbs2p plays a different role in osmoadaptation and calcofluor sensitivity. We have isolated a gene homologous to PBS2 from the highly salt-tolerant yeast Debaryomyces hansenii by phenotypic complementation. DNA sequencing of the clone revealed that the gene encoded a protein of 683 amino acid residues. Like Pbs2p, this protein also has a proline-rich motif. Further characterization revealed that this gene could complement polymyxin B sensitivity but did not affect calcofluor sensitivity. Thus, it appeared that Pbs2p also has an independent role in these two physiological processes. The GenBank Accession No. of this sequence is AF371315.     

A highly integrated multifunction macro synthesizer chip (MMSC) forapplications in 2-18 GHz synthesized sources

A highly integrated monolithic microwave integrated circuit (MMIC) that acts as the core of the RF section of a synthesized source is developed using commercially available 0.2-μm pseudomorphic high electron mobility transistor (PHEMT) technology. Measured performance is shown up to 18 GHz. The same system architecture is able to produce synthesized output through 40 GHz with modifications of some critical building blocks of the chip. The chip performs all the frequency selection and tuning functions. It has more than 30 RF blocks integrated on an area of 4.27×4.68 mml. Some individual blocks operate through 40 GHz     

Spontaneous perforation of the gallbladder during infancy diagnosed on hepatobiliary imaging

The purpose of this study was to determine the effectiveness of specialty pads as an intervention to reduce the incidence of intraoperatively acquired pressure sores. A convenience sample (N = 361) was drawn from all inpatients who underwent cardiothoracic or major vascular surgery on the standard operating room table (group 1), the air-filled pad (group 2), or the specialty foam pad (group 3). This sample was inclusive of 100% of patients during the study period who met the criteria. The incidence of pressure sore development was seven in group 1, zero in group 2, and one in group 3. There was at statistically significant difference (p = 0.0003) between group 1 and group 2. Additionally, a statistically significant difference (p = 0.0003) was found between group 1 and group 3. The foam pad and the air-filled pad were effective interventions for reducing the risk of intraoperatively acquired pressure sores.     

Compact Wideband Bandpass Filters With Wide Upper Stopband

In this letter, a T-shaped microstrip feeding arrangement is proposed to design wideband bandpass filter (BPF) using shorted slot-line resonators. This feed line produces frequency selective external coupling which is utilized to suppress unwanted harmonics. Up to sixth order harmonics are suppressed. Other advantages are low passband group delay variation, ease of fabrication, low insertion loss (IL), and compact size. A fabricated BPF of fractional bandwidth 56.3% at midband frequency 2.3 GHz has a maximum IL of 1.2 dB in its passband and 30-dB upper stopband extends over 11.53 GHz     

Abrasive wear behaviour of zinc-aluminium alloy - 10% Al2O3 composite through factorial design of experiment

Two body abrasive wear behaviour of a zinc-aluminium alloy - 10% Al₂O₃ composite was studied at different loads (1–7 N) and abrasive sizes (20–275 m) as a function of sliding distance and compared with the matrix alloy. The wear rate of the composite and the matrix alloy has been expressed in terms of the applied load, abrasive size and sliding distance using linear factorial design approach. The study suggests that the wear rate of the alloy and composite follow the following relations: