Scan blindness free phased array design using PBG materials

Scan blindness occurs for phased arrays when propagation constants of Floquet modes (space harmonics) coincide with those of surface waves supported by the array structure. In this paper, we studied the possibility of using photonic band-gap (PBG) substrate to eliminate scan blindness. A specially designed printed PBG substrate can suppress surface wave propagation inside its bandgap range, therefore it can be used to eliminate scan blindness. In this paper, we presented a method of moments (MoM) analysis of the scan properties of dipole arrays on PBG substrates with ominidirectional bandgap(s). We found that scan blindness is completely eliminated. The elimination of scan blindness makes PBG materials very attractive in phased array design.     

Drug-induced acute interstitial nephritis

This paper reports the findings of a five-year, three-stage study of the occupational status persistence of 333 physicians who immigrated to Israel from the former Soviet Union in 1990. The first data collection, by way of a structured questionnaire in Russian, was undertaken in 1991, during their participation in preparatory courses for the medical licensure examination. The second and third stages of data collection were undertaken by mail in 1993 and 1995. Data are presented regarding the influence of gender and age on employment status and on the relationship between employment status and psycho-social well-being, including work and general satisfaction, self-esteem, mood, health and overall adaptation, at both stages. The dynamics of occupational integration are investigated by looking at the effects of occupational stability vs occupational change between stage 2 and stage 3 on the psycho social outcome variables. After three years in Israel, men were more likely to be working as physicians than women, and women were more likely to be unemployed. However, after five years, women were equally likely to have found work in their profession, albeit in lower status positions. Younger respondents were more successful than older respondents in passing the licensure examination, finding work in their profession, and entering residency programs. The gap between them did not close between stage 2 and stage 3. At both stage 2 and stage 3, those working as physicians had significantly more positive well-being scores than those not working as physicians. All occupational groups had more positive scores at stage 3 than at stage 2, except for those who were working in non-medically related jobs. The greatest improvement in psycho-social well-being was among those who became physicians between stage 2 and stage 3, compared to those who were not physicians at either stage and those who were physicians at both stages.     

Pulse scattering from a sphere coated with an inhomogeneous sheath

The backscattered waveform produced by a short electromagnetic pulse incident upon a metallic sphere clad with a radially stratified dielectric is considered. Typical results are presented which demonstrate the dependence of the specular and creeping wave returns on the permittivity gradient and thickness of the sheath.     

Quality assessment of artificially aged A357 aluminum alloy cast ingots by introducing approximate expressions of the quality index <Emphasis Type="Italic">Q</Emphasis><Subscript><Emphasis Type="Italic">D</Emphasis></Subscript>

The mechanical performance of A357 cast ingot aluminum alloy specimens subjected to 25 different artificial aging heat treatments has been experimentally investigated. For the quality evaluation of the artificially aged alloys, the quality index Q _D , proposed by the authors, has been involved. The index Q _D interprets quality as the potential of an alloy to offer combinations of tensile strength, ductility, and toughness at certain levels of values. The evaluation of the alloy quality using Q _D relies on the availability of the materials tensile flow curve. To facilitate the exploitation of Q _D for quality assessment, approximations of Q _D are developed. In the proposed approximations, Q _D is formulated as a function of ultimate tensile strength, yield strength, and elongation to fracture, or alternatively, as a function of Rockwell hardness E and Charpy impact energy values. Accurate estimations of the quality index Q _D are compared against Q _D values obtained by using the proposed approximations.     

A method for comparing flexibility performance for the lifecycle of manufacturing systems under capacity planning constraints

The objective of this work is to describe a method for comparing the flexibility performance of manufacturing systems, in an uncertain environment, under lifecycle considerations and capacity planning constraints. The manufacturing systems costs are estimated over a time horizon and for a large variety of possible market scenarios. In order for the lifecycle cost values to be comparable among different systems, their values are calculated with the use of a special purpose algorithm. Statistical analysis of the estimated cost values is then employed for assessing the flexibility of each manufacturing system. The method is applied in an industrial case for checking, also from a flexibility point of view, the investment on a production system, using real life industrial data.     

Occurrence and Antibiotic Susceptibility Profile of Streptococcus spp. Isolated from Ewe＇s Milk

The purpose of this study was to determine the occurrence and antimicrobial resistance of Streptococcus spp. isolated from fresh ewe＇s milk and consequently to draw conclusions concerning the health condition of the animal flocks and the current trends of antibiotic use in small ruminants. A total of 77 mountainous sheepfolds were investigated representing 10% of all transhumant sheep and goats flocks in the area. Duplicate milk samples were collected from January to February transferred to the laboratory and analyzed for the presence of Streptococcus spp. by using the serial dilution method and plating on the surface of Slanetz and Bartley agar. The isolates were tested against nine antimicrobial agents with the Kirby-Bauer disk diffusion method. The results showed that Streptococcus spp. occurred in 84.4% of the samples and in counts ranged between 1.8 log CFU/mL and 4.6 log CFU/mL. Concerning susceptibility, only 1.3% of the isolates were resistant to all antimicrobials while 27.3% were fully susceptible. Resistance to cefepime was the most common （93.1%） observation followed by resistance to ampicillin （82.1%）, ciprofloxacine （58.3%） and meropenem （51.9%）. The isolates were vancomycin susceptible at a rate of 83.6%. Multidrug resistance to at least three antibiotics was observed to be 22.1% of Streptococcus spp.. Given the prevalence of Streptococcus spp. and the elevated resistance of isolates to various antibiotics it is concluded that further examinations and even interventions are required in order to pertain the appropriate animal health and milk quality.     

Part I: Dynamic evolution of the particle size distribution in particulate processes undergoing combined particle growth and aggregation

The present study provides a comprehensive investigation on the numerical problems arising in the solution of dynamic population balance equations (PBEs) for particulate processes undergoing simultaneous particle growth and aggregation. The general PBE was numerically solved in both the continuous and its equivalent discrete form using the orthogonal collocation on finite elements (OCFE) and the discretized PBE method (DPBE), respectively. A detailed investigation on the effect of different particle growth rate functions on the calculated PSD was carried out over a wide range of variation of dimensionless aggregation and growth times. The performance (i.e., accuracy and stability) of the employed numerical methods was assessed by a direct comparison of predicted PSDs or/and their respective moments to available analytical solutions. It was found that the OCFE method was in general more accurate than the discretized PBE method but was susceptible to numerical instabilities. On the other hand, for growth dominated systems, the discretized PBE method was very robust but suffered from poor accuracy. For both methods, discretization of the volume domain was found to affect significantly the performance of the numerical solution. The optimal discretization of the volume domain was closely related with the satisfactory resolution of the time-varying PSD. Finally, it was shown that, in specific cases, further improvement of the numerical results could be obtained with the addition of an artificial diffusion term or the use of a moment-weighting method to correct the calculated PSD.     

Design of transversely fed EMC microstrip dipole arrays includingmutual coupling

Design techniques and procedures for microstrip dipole arrays transversely fed by proximity coupled microstrip lines are presented. Two design equations which include the effects of mutual coupling are developed, and the corresponding design curves are obtained by a rigorous integral equation solution. A seven-element standing wave linear array is designed to illustrate the developed design procedures. The design data are checked by a complete integral equation solution of the array, with good agreement. The measurements of radiation pattern and input impedance are found to be in good agreement with the design goal