A Gm-C bump equalizer for low-voltage low-power applications

A low-voltage low-power 2nd-order CMOS pseudo-differential bump-equalizer is presented. Its topology comprises a bandpass section with adjustable center frequency and quality factor, together with a programmable current amplifier. The basic building blocks are triode-operating transconductors, tunable by means of either a DC voltage or a digitally controlled current divider. The bump-equalizer as part of a battery-operated hearing aid device is designed for a 1.4V-supply and a 0.35μm CMOS fabrication process. The circuit performance is supported by a set of simulation results, which indicates a center frequency from 600Hz to 2.4kHz, 1≤Q≤5, and an adjustable gain within ±6dB at center frequency. The filter dynamic range lies around 40dB. Quiescent consumption is kept below 12μW for any configuration of the filter.

Growth of Chrysanthemum grandiflorum in different peats and change of peat properties during cultivation

Marketable chrysanthemums were produced in several different peat types. Only the plants in one of the dredged frozen black peats and one of the milled white peats had a significant lower shoot dry weight than those in one of the sod and milled white peats, respectively. As the N-contents of the fertilized peats show neither deficiency nor excess in nutrient supply, possibly they are not the reason for the differences in shoot dry weight. The air capacity, which is extremely low in both dredged frozen black peats and dropped further during the cultivation period due to decomposition, also cannot explain the differences in shoot dry weight sufficiently (R2=0.44*; n=12). A close linear negative correlation (R2=0.77** n=12) was found between the CAT (VDLUFA) soluble Fe and the shoot dry weight. Therefore, the Fecontents might be a quality factor of peat to be used as a growing medium.

Microstructure, crystalline phase, and dielectric property analyses of TiO2 composition with ZrO2 addition

For microwave applications, including mobile and satellite communications, ceramic resonators should have a high dielectric constant, low dielectric losses, and high frequency stability. In this sense, TiO2-ZrO 2 ceramics have been investigated as a function of sintering behavior, phase composition, and microstructure. The ceramics were densified reaching a value of about 86% of theoretical density at 1400°C sintering temperature. The ceramics are prepared by mixing raw materials with the following TiO2-ZrO2 weight % ratio: 100 to 0, 90 to 10, and 80 to 20, respectively. The measured dielectric constants are between 79 and 88 values, while the quality factor due to dielectric losses are between 2820 and 5170. These results point out the influence of Ti/Zr ratio on controlling the dielectric properties. © (2010) Trans Tech Publications.

Sintering temperature influence on microwave dielectric properties of TiO2-ZrO2 ceramics

Dielectric ceramics have been widely investigated and used for microwave applications such as resonators and filters. The present study deals with the influence of sintering temperature on microwave dielectric properties of TiO2 ceramics with 10, 20, and 30 wt% ZrO2. Three compositions have been developed through mixing procedures and then tested for each sintering temperature: 1500 and 1400°C. X-ray diffraction and scanning electron microscopy are carried out aiming to explain the ceramic behavior of each sample. The dielectric constants of different ceramics for both temperatures varied from 85.4 to 62.6, while their quality factor due to dielectric losses varied from 3110 to 1630. The Q decrease is attributed to the non uniform grain growth and to the obtained crystalline phases. The best microwave parameters were obtained for the ceramics sintered at 1400°C, which can be applied in microwave circuits as dielectric resonators. © (2010) Trans Tech Publications.

Fatores produtivos e industriais que interferem na qualidade da carne bovina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Superfícies eletromagnéticas de microondas com controle do regime de trapped-mode

Neste trabalho foram investigadas (FSSs) com ressonância de alto fator de qualidade (fator Q) e independência da polarização para uma onda plana com incidência normal. Estas FSSs são baseadas em um arranjo planar de metalizações sobre um substrato. Um alto fator Q é obtido por meio da excitação do trapped-mode e a independência da polarização, por meio da alta simetria rotacional dos elementos que compõe o arranjo. Para o projeto de FSSs com controle do regime de trapped-mode, foram utilizados substratos feitos de materiais com possibilidade de controle de suas propriedades elétricas ou magnéticas (ferrite magnetizada ou silício ativado oticamente). O arranjo de dois anéis concêntricos em um substrato dielétrico analisado neste trabalho apresenta uma ressonância de trapped-mode com fator Q em torno de 12 e transmitância máxima de 70 %. Com a utilização de um substrato de ferrite magnetizada nesse arranjo, é mostrado que é possível deslocar a frequência de ressonância do trappedmode em torno de 20 %, sem degradação significativa da ressonância de transmisão. Com o emprego de um substrato de silício ativado opticamente, é demonstrado que é possível realizar um chaveamento praticamente completo da banda de transmissão desse arranjo. Para realização das simulações computacionais foram utilizados o método dos momentos no domínio espectral (SDMM) e os programas comerciais Ansoft Designer 5 Planar EM e CST 2009.

Estudo da dose efetiva, razão sinal-ruído e razão contraste-ruído em tomografia computadorizada de múltiplos detetores

Since discovery, computed tomography is a widely used diagnostic modality. However, this modality imparts relatively high doses to the patients and with fast technological advancement, it is necessary optimize the doses used and ensure the quality of the images through a quality assurance program. This work intended to compare Computed Tomography Dose Index (CTDIW) and effective dose with components of image quality: the Contrast-to-Noise Ratio (CNR) and Signal-to-Noise Ratio (SNR), and a quality factor (Q) deduced by the Rose model for two groups of computed tomography units. The first group was composed by equipments with 10 up to 16 slices and the second one presented 40 up to 320 slices detectors, for the protocols of head and abdomen. It was realized a comparison between different selectable parameters in the protocol of a Philips Brilliance 16, too. The results of the first group to CTDIW, effective dose, SNR and CNR showed variations of 28%, 33%, 37% and 32% respectively for head protocol, and 21%, 27%, 43% and 37% respectively for abdomen protocol. The results of the group 2 to CTDIW, effective dose, SNR and CNR showed variations of 15%, 26%, 36% and 34% respectively for the head protocol, and 8%, 13%, 50% and 60% respectively for abdomen protocol. The comparison between both groups demonstrated similar levels of doses impartation to patients though having so many different configurations, if the uncertainties associated with this measurement were considered. The results of the comparison between different parameters in the Philips Brilliance 16 scanner were in agreement with expected

EC28-234 Nebraska System for Tattooing Hogs for Identification after Slaughter

A plan to identify the individual farm upon which hogs reaching markets are produced has been developed in connection with the efforts toward eradicating tuberculosis among farm animals. While primarily intended as a means of tracing back to determine sources of disease infection, the system of tattooing which is being developed has other significant possibilities. With the growing emphasis on quality products in the market, it is only fair that the producers of high quality commodities receive the premiums paid by processors and consumers. Health of farm animals is a quality factor. The producer of healthy hogs should be rewarded. Likewise, the producer of diseased hogs profits from knowledge that his animals are infected and can institute efforts to control that source fo loss. This 1928 extension circular covers what each letter of a tattoo stands for, where it is to be placed on an animal, and material used in tattooing.

Structural refinement, optical and microwave dielectric properties of BaZrO3

In this work, barium zirconate (BaZrO3) ceramics synthesized by solid state reaction method and sintered at 1670 degrees C for 4 h were characterized by X-ray diffraction (XRD), Rietveld refinement, and Fourier transform infrared (FT-IR) spectroscopy. XRD patterns, Rietveld refinement data and FT-IR spectra which confirmed that BaZrO3 ceramics have a perovskite-type cubic structure. Optical properties were investigated by ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) measurements. UV-vis absorption spectra suggested an indirect allowed transition with the existence of intermediary energy levels within the band gap. Intense visible green PL emission was observed in BaZrO3 ceramics upon excitation with a 350 nm wavelength. This behavior is due to a majority of deep defects within the band gap caused by symmetry breaking in octahedral [ZrO6] clusters in the lattice. The microwave dielectric constant and quality factor were measured using the method proposed by Hakki-Coleman. The dielectric resonator antenna (DRA) was investigated experimentally and numerically using a monopole antenna through an infinite ground plane and Ansoft's high frequency structure simulator software, respectively. The required resonance frequency and bandwidth of DRA were investigated by adjusting the dimension of the same material. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Transiting exoplanets from the CoRoT space mission XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 +/- 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were used to derive stellar and planetary parameters. The planet has a mass of M-p = 2.8 +/- 0.3 M-Jup, a radius of R-pl = 1.05 +/- 0.13 R-Jup, a density of approximate to 3 gcm(-3). RV data also clearly reveal a nonzero eccentricity of e = 0.16 +/- 0.02. The planet orbits a mature G0 main sequence star of V = 15.5 mag, with a mass M-star = 1.14 +/- 0.08 M-circle dot, a radius R-star = 1. 61 +/- 0.18 R-circle dot and quasi-solar abundances. The age of the system is evaluated to be 7 Gyr, not far from the transition to subgiant, in agreement with the rather large stellar radius. The two features of a significant eccentricity of the orbit and of a fairly high density are fairly uncommon for a hot Jupiter. The high density is, however, consistent with a model of contraction of a planet at this mass, given the age of the system. On the other hand, at such an age, circularization is expected to be completed. In fact, we show that for this planetary mass and orbital distance, any initial eccentricity should not totally vanish after 7 Gyr, as long as the tidal quality factor Q(p) is more than a few 10(5), a value that is the lower bound of the usually expected range. Even if CoRoT-23b features a density and an eccentricity that are atypical of a hot Jupiter, it is thus not an enigmatic object.

Development of a slow-wave MEMS phase shifter on CMOS technology for millimeter wave frequencies

We propose a slow-wave MEMS phase shifter that can be fabricated using the CMOS back-end and an additional maskless post-process etch. The tunable phase shifter concept is formed by a conventional slow-wave transmission line. The metallic ribbons that form the patterned floating shield of this type of structure are released to allow motion when a control voltage is applied, which changes the characteristic impedance and the phase velocity. For this device a quality factor greater than 40 can be maintained, resulting in a figure of merit on the order of 0.7 dB/360 degrees and a total area smaller than 0.14 mm(2) for a 60-GHz working frequency. (C) 2011 Elsevier B.V. All rights reserved.

Time lags of the kilohertz quasi-periodic oscillations in the low-mass X-ray binaries 4U 1608−52 and 4U 1636−53

We studied the energy and frequency dependence of the Fourier time lags and intrinsic coherence of the kilohertz quasi-periodic oscillations (kHz QPOs) in the neutron-star lowmass X-ray binaries 4U 1608−52 and 4U 1636−53, using a large data set obtained with the Rossi X-ray Timing Explorer. We confirmed that, in both sources, the time lags of the lower kHz QPO are soft and their magnitude increases with energy. We also found that: (i) In 4U 1636−53, the soft lags of the lower kHz QPO remain constant at∼30 μs in the QPO frequency range 500–850 Hz, and decrease to ∼10 μs when the QPO frequency increases further. In 4U 1608−52, the soft lags of the lower kHz QPO remain constant at 40 μs up to 800 Hz, the highest frequency reached by this QPO in our data. (ii) In both sources, the time lags of the upper kHz QPO are hard, independent of energy or frequency and inconsistent with the soft lags of the lower kHz QPO. (iii) In both sources the intrinsic coherence of the lower kHz QPO remains constant at ∼0.6 between 5 and 12 keV, and drops to zero above that energy. The intrinsic coherence of the upper kHz QPO is consistent with being zero across the full energy range. (iv) In 4U 1636−53, the intrinsic coherence of the lower kHz QPO increases from ∼0 at ∼600 Hz to ∼1, and it decreases to ∼0.5 at 920 Hz; in 4U 1608−52, the intrinsic coherence is consistent with the same trend. (v) In both sources the intrinsic coherence of the upper kHz QPO is consistent with zero over the full frequency range of the QPO, except in 4U 1636−53 between 700 and 900 Hz where the intrinsic coherence marginally increases. We discuss our results in the context of scenarios in which the soft lags are either due to reflection off the accretion disc or up-/down-scattering in a hot medium close to the neutron star. We finally explore the connection between, on one hand the time lags and the intrinsic coherence of the kHz QPOs, and on the other the QPOs’ amplitude and quality factor in these two sources.

Tidal perturbations of the rotation of the moon: the creep tide approach

In this communication we report results from the application to the study of the rotation of the Moon of the creeping tide theory just proposed (Ferraz-Mello, Cel. Mech. Dyn. Astron., submitted. ArXiv astro-ph 1204.3957). The choice of the Moon for the first application of this new theory is motivated by the fact that the Moon is one of the best observed celestial bodies and the comparison of the theoretical predictions of the theory with observations i may validate the theory or point out the need of further improvements. Particularly, the tidal perturbations of the rotation of the Moon - the physical libration of the Moon - have been detected in the Lunar Laser Ranging measurements (Williams et al. JGR 106, 27933, 2001). The major difficulty in this application comes from the fact that tidal torques in a planet-satellite system are very sensitive to the distance between the two-bodies, which is strongly affected by Solar perturbations. In the case of the Moon, the main solar perturbations - the Evection and the Variation - are more important than most of the Keplerian oscillations, being smaller only than the first Keplerian harmonic (equation of the centre). Besides, two of the three components of the Moon's libration in longitude whose tidal contributions were determined by LLR are related to these perturbations. The results may allow us to determine the main parameter of a possible Moon's creeping tide. The preliminary results point to a relaxation factor (gamma) 2 to 4 times smaller than the one predicted from the often cited values of thr Moon's quality factor Q (between 30 and 40), and points to larger Q values.

Bottle microresonators for applications in quantum optics and all-optical signal processing

This thesis reports on the experimental realization, characterization and application of a novel microresonator design. The so-called “bottle microresonator” sustains whispering-gallery modes in which light fields are confined near the surface of the micron-sized silica structure by continuous total internal reflection. While whispering-gallery mode resonators in general exhibit outstanding properties in terms of both temporal and spatial confinement of light fields, their monolithic design makes tuning of their resonance frequency difficult. This impedes their use, e.g., in cavity quantum electrodynamics (CQED) experiments, which investigate the interaction of single quantum mechanical emitters of predetermined resonance frequency with a cavity mode. In contrast, the highly prolate shape of the bottle microresonators gives rise to a customizable mode structure, enabling full tunability. The thesis is organized as follows: In chapter I, I give a brief overview of different types of optical microresonators. Important quantities, such as the quality factor Q and the mode volume V, which characterize the temporal and spatial confinement of the light field are introduced. In chapter II, a wave equation calculation of the modes of a bottle microresonator is presented. The intensity distribution of different bottle modes is derived and their mode volume is calculated. A brief description of light propagation in ultra-thin optical fibers, which are used to couple light into and out of bottle modes, is given as well. The chapter concludes with a presentation of the fabrication techniques of both structures. Chapter III presents experimental results on highly efficient, nearly lossless coupling of light into bottle modes as well as their spatial and spectral characterization. Ultra-high intrinsic quality factors exceeding 360 million as well as full tunability are demonstrated. In chapter IV, the bottle microresonator in add-drop configuration, i.e., with two ultra-thin fibers coupled to one bottle mode, is discussed. The highly efficient, nearly lossless coupling characteristics of each fiber combined with the resonator's high intrinsic quality factor, enable resonant power transfers between both fibers with efficiencies exceeding 90%. Moreover, the favorable ratio of absorption and the nonlinear refractive index of silica yields optical Kerr bistability at record low powers on the order of 50 µW. Combined with the add-drop configuration, this allows one to route optical signals between the outputs of both ultra-thin fibers, simply by varying the input power, thereby enabling applications in all-optical signal processing. Finally, in chapter V, I discuss the potential of the bottle microresonator for CQED experiments with single atoms. Its Q/V-ratio, which determines the ratio of the atom-cavity coupling rate to the dissipative rates of the subsystems, aligns with the values obtained for state-of-the-art CQED microresonators. In combination with its full tunability and the possibility of highly efficient light transfer to and from the bottle mode, this makes the bottle microresonator a unique tool for quantum optics applications.

Simulationsgestützte Untersuchung der Spurtreue von Routenzügen

Für den innerbetrieblichen Transport und besonders für die Materialversorgung in der Produktion werden zunehmend Routenzüge eingesetzt, die aus einem Schleppfahrzeug und bis zu fünf Anhängern bestehen. Um gute Manövrierbarkeit und einen geringen Platzbedarf zu gewährleisten, sollten Routenzuganhänger möglichst spurtreu sein. In diesem Beitrag wird die Spurtreue exemplarisch für zwei am Markt verfügbare Anhänger für Routenzüge mit zwei ungelenkten und vier gelenkten Rädern untersucht. Hierfür wird zunächst ein Gütekriterium definiert, das die maximale Abweichung von der Spurtreue quantitativ erfasst. Außerdem werden Testszenarien vorgeschlagen, um die verschiedenen Fahrwerks- und Lenkkonzepte vergleichen zu können. Mit Hilfe eines entwickelten analytischen Modells werden die Abweichungen in der Spurtreue bei stationärer Kreisfahrt für die zwei gewählten Konzepte berechnet und dargestellt. Zusätzlich wird eine Mehrkörper-Simulation, die eine tiefere physikalische Modellierung und die Untersuchung komplexerer Fahrmanöver erlaubt, durchgeführt und mit den analytischen Ergebnissen verglichen. Es kann gezeigt werden, dass neben der Lenkkinematik weitere Parameter wie das Schräglaufverhalten der Reifen Einfluss auf die Spurtreue haben.