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Proposed Configuration (proposed + configuration)
Selected AbstractsA configuration for realizing floating, linear, voltage-controlled resistance, inductance and FDNC elementsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5 2009R. Senani Abstract A configuration using current feedback amplifiers has been presented, which is capable of realizing linear, positive/negative voltage-controlled resistance, voltage-controlled inductance and voltage-controlled frequency-dependent negative conductance in floating form (and thereby, also in grounded form) from the same structure. The workability of the proposed configuration has been demonstrated by hardware implementation results using AD 844-type current feedback op-amps (CFOAs) and BFW-11-type JFETs and the workability in high-frequency range has been demonstrated by SPICE simulation using CMOS CFOAs. Copyright © 2008 John Wiley & Sons, Ltd. [source] Computational study of staged membrane reactor configurations for methane steam reforming.AICHE JOURNAL, Issue 1 2010Abstract The present work complements part I of this article and completes a computational analysis of the performances of staged membrane reactors for methane steam reforming. The influence of the number of stages and catalyst amount is investigated by comparing the methane conversion and hydrogen recovery yield achieved by an equisized-staged reactor to those of an equivalent conventional membrane reactor for different furnace temperatures and flow configurations (co- and counter-current). The most relevant result is that the proposed configuration with a sufficiently high number of stages and a significantly smaller catalyst amount (up to 70% lower) can achieve performances very close to the ones of the conventional unit in all the operating conditions considered. This is equivalent to say that the staged configuration can compensate and in fact substitute a significant part of the catalyst mass of a conventional membrane reactor. To help the interpretation of these results, stage-by-stage temperature and flux profiles are examined in detail. Then, the quantification of the performance losses with respect to the conventional reactor is carried out by evaluating the catalyst amount possibly saved and furnace temperature reduction. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] A proposal for high resolution photolithography using optical limitersLASER PHYSICS LETTERS, Issue 9 2004A. Rostami Abstract The main problem of the traditional photolithography in microelectronics and photonics Engineering (minimum linewidth) can be relaxed using optical limiters. In this work, nonlinear Bragg Grating (Kerr-Like non-linearity) is used as an optical limiter. Also, a suitable setup configuration for high-resolution photolithography based on optical limiter is proposed. The minimum line-width for integrated systems with our proposed configuration depends on the Grating parameters. We show that, the linear and nonlinear index of refractions profile, and the number of layers in the proposed grating, determines the minimum line-width. (© 2004 by ASTRO, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Design and performance of ultra low phase noise reflection whispering gallery resonator oscillatorMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2007Nicolás A. Shtin Abstract This article deals with the design and experimental testing of the ultra low phase noise reflection oscillator incorporating a sapphire whispering gallery resonator (WGR). On a contrast with the conventional loop configuration oscillators with transmission WGR the presented oscillator is based on a reflection WGR excited by a single probe. It is shown that a phase noise of C-band oscillator of the proposed configuration can be as low as ,136 dBc/Hz at 1-kHz Fourier frequency. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2026,2030, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22623 [source] Microstrip-fed slot antennas backed by a very thin cavityMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2007Andrea Vallecchi Abstract Slot antennas with a backing cavity for unidirectional radiation are investigated with the aim of achieving a thin structure capable of reasonably broadband operation. By tuning together the slot length and the cavity cross-section, a very low-profile cavity-backed slot (CBS) is demonstrated. The cavity thickness of this slot antenna is about 10 times smaller than conventional one-quarter wavelength cavities, which would allow constructing this antenna even with standard cost-effective multilayer planar technology. The high gain and fairly wideband operation are the major advantages of the proposed configuration, which features a bandwidth of about 10% at a center frequency of 1.8 GHz with radiation efficiency in excess of 80%. Measured data are presented and compared with simulation results obtained by both the method of moments (MoM) and the finite integration technique (FIT). © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 247,250, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22073 [source] Optimizing Service Attributes: The Seller's Utility Problem,DECISION SCIENCES, Issue 2 2001Fred F. Easton Abstract Service designers predict market share and sales for their new designs by estimating consumer utilities. The service's technical features (for example, overnight parcel delivery), its price, and the nature of consumer interactions with the service delivery system influence those utilities. Price and the service's technical features are usually quite objective and readily ascertained by the consumer. However, consumer perceptions about their interactions with the service delivery system are usually far more subjective. Furthermore, service designers can only hope to influence those perceptions indirectly through their decisions about nonlinear processes such as employee recruiting, training, and scheduling policies. Like the service's technical features, these process choices affect quality perceptions, market share, revenues, costs, and profits. We propose a heuristic for the NP-hard service design problem that integrates realistic service delivery cost models with conjoint analysis. The resulting seller's utility function links expected profits to the intensity of a service's influential attributes and also reveals an ideal setting or level for each service attribute. In tests with simulated service design problems, our proposed configurations compare quite favorably with the designs suggested by other normative service design heuristics. [source] Behaviour of carbamate pesticides in gas chromatography and their determination with solid-phase extraction and solid-phase microextraction as preconcentration stepsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 16 2005Rita Carabias-Martínez Abstract This work reports a study of the chromatographic behaviour of seven carbamate pesticides (aldicarb, carbetamide, propoxur, carbofuran, carbaryl, methiocarb, and pirimicarb) by gas chromatography-mass spectrometry (GC-MS). Variables such as injector temperature, solvent, injection mode, and the degree of ageing of the chromatographic column were studied. One of the aims of this work was to achieve a controlled decomposition of carbamates by a solid-phase microextraction (SPME) preconcentration step with a polyacrylate fibre in order to obtain reproducible chromatographic signals of the degradation products. Optimisation of the SPME process was accomplished by means of experimental design. Several methods using ultrapure water were developed with different preconcentration configurations: SPME-GC-MS, SPE followed by SPME-GC-MS, and SPE plus GC-MS. For all the pesticides studied, method detection limit (MDL) values below 0.1 ,g L,1 were reached in at least one of the proposed configurations. [source] | |||||||||||||