Frequency response of a thin cobalt film magnetooptic sensor

The magnetooptic effect is due to a change in the polarization of the light when it is reflected or passes through a magnetized material. The rotation of the polarization plane is proportional to the magnetic field. The great advantage of using a magnetooptic sensor to measure intensity or magnetic fields is its wide bandwidth. This fact is widely known; however, no effective measurements have been taken. In this paper, we present the frequency response of a cobalt thin film used as magnetooptic material. It was first excited by several sinusoidal magnetic fields at different frequencies. The range of frequencies studied in the first experiment reached 179 Hz, which is suitable for measuring power line intensity or magnetic fields. Because the coil that creates the magnetic field has a great impedance at higher frequencies, an alternative method based on magnetic impulses has been designed to obtain high-frequency data. With the latest experiments we have been able to measure frequencies as high as 2 MHz, obtaining a flat frequency response.     

The auto repair shop model: A vehicle for the transmission of management technology.

Presents an analogy between an automobile repair shop and a mental health service delivery unit. Examples of recent technological advances in mental health are categorized according to a business model and advantages of such an approach noted. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Experimental Study on the Air-Side Heat Transfer Coefficient and the Thermal Contact Conductance in Finned Tubes

The objective of this experimental study is to evaluate the heat transfer coefficient outside a tube with annular transverse fins, derived from strips of copper mechanically bound and coupled outside. Water is used as the heating medium, in turbulent conditions and flowing at different temperatures inside the tube. Petukhov's correlation has been selected to calculate the water heat transfer coefficient in the tube. The experimental data obtained are compared with a correlation from literature, and a similar trend is observed. A fitting of the data provides a correlation for the three tubes of different external diameter (30 mm, 22 mm, and 15.6 mm) that agrees very well with the experimental values. The thermal contact conductance is identified as the main reason for the difference between data and the original Briggs and Young correlation. An estimation of the contact conductance between fins and tubes provides values between 3500 and 11000 W/m²-K, slightly increasing with the air Reynolds number (based on the external diameter of the tube), whose range is 2000 to 8000. The thermal contact resistance is estimated and its importance is confirmed, contributing 30 to 50% to the total air-side thermal resistance in the tubes used in the experiments.     

Design of a low-complexity adaptive interference-mitigatingdetector for DS/SS receivers in CDMA radio networks

Code-division multiple-access (CDMA) with direct-sequence/spread-spectrum (DS/SS) modulated signals has emerged as a strong candidate for the air interface of the universal wireless personal communication network planned for the end of the century. In this paper, we take into consideration a low-complexity blind adaptive interference-mitigating detector (BAID) scheme that minimizes the detrimental effect of the multiple-access interference (MAI) on the bit-error-rate (BER) performance of a CDMA data demodulator. We describe a few modifications to the original algorithm that make it more suitable to a practical implementation with dual-binary phase-shift keying (D-BPSK)-modulated DS/SS signals. Specifically, we show how to make the BAID invariant to a possible carrier phase offset introduced in the front-end of the data demodulator, and we also suggest how to increase the robustness of such detector to asynchronous MAI. The uncoded BER performance of the resulting “extended” detector is then evaluated theoretically and by computer simulation in the case of coherent and differential signal detection     

A frequency error resistant blind CDMA detector

This paper presents an enhanced version of the previously proposed blind anchored interference-mitigating detector (BAID) for code-division multiple-access transmission. Such a detector, named extended complex BAID (EC-BAID), features invariance to a phase error on the useful channel's carrier and reveals resistance to a large frequency shift (e.g., Doppler shift) on interfering carriers. The EC-BAID is also shown to bear a sensitivity to residual carrier frequency errors on the desired channel which is lower by three orders of magnitude with respect to the case of a data-aided minimum mean-square-error receiver. The performance of the EC-BAID is computed theoretically, and is validated by computer simulations under a variety of system configurations     

Computationally efficient ray-tracing technique for modelling ultrawideband indoor propagation channels

The design and development of high-speed data wireless communication systems within buildings call for the investigation of the ultrawideband indoor propagation channel. To date, ray tracing (RT) based approaches have been widely used to characterise the channel; unfortunately, such techniques, although accurate, turn out computationally intensive. In this work, a parallel ray (PR) approximation is successfully used to significantly improve the computational efficiency of the RT method. The accuracy and the applicability of the proposed approximation are assessed through the analysis of the mean square error between the impulse responses obtained with the PR and the RT methods.     

Ultra low-noise current sources

The solid state DC current sources available on the market are not suitable for applications in low noise measurement systems because of the high level of low-frequency noise introduced in the measurement chain. The most important cause of low-frequency noise in such instruments is the solid state device used as a voltage reference (usually a Zener diode). This problem has been solved, in the instrument described in this paper, by using a new circuit topology in which the solid-state voltage reference has been substituted by a low-noise battery. The instrument, capable of supplying a current as high as 100 mA, is characterized by a low-frequency noise level some orders of magnitude lower than that of similar commercial instrumentation     

A two-level fanout system for the CDF silicon vertex tracker

The Fanout system is part of the Silicon Vertex Tracker (SVT), a new trigger processor designed to reconstruct charged particle trajectories at level 2 (L2) of the CDF trigger, with a latency of 10 μs and an event rate up to 100 kHz. The core of SVT is organized as 12 identical slices, which process in parallel the data from the 12 independent azimuthal wedges of the Silicon Vertex Detector (SVXII). Each SVT slice links the digitized pulse heights found within one SVXII wedge to the tracks reconstructed by the level I (L1) fast track finder (XFT) in the corresponding 30° angular region of the Central Outer Tracker (COT). Since the XFT tracks are transmitted to SVT as a single data stream, their distribution to the proper SVT slices requires dedicated fanout logic. The fanout system has been implemented as a multiboard project running on a common 20 MHz clock. Track fanout is performed in two steps by one "Fanout A" and two "Fanout B" boards. The architecture, design, and implementation of this system are described     

Furosine and flavour compounds in durum wheat pasta produced under different manufacturing conditions: Multivariate chemometric characterization

The headspace solid-phase microextraction (HS-SPME) technique followed by GC/MS analysis was performed to evaluate the volatile fraction of durum wheat pasta produced under different process conditions (artisan manufacturing methods or industrial processes). At the same time, HPLC analysis was performed to quantify furosine in the same pasta samples. Furosine is commonly used as an index of nutritional damage occurring during pasta drying, although drastic thermal treatments may lead to its underestimation. Moreover, since furosine determination requires time/solvent-consuming methods, a more convenient approach could be the identification of volatile compounds formed during the drying step and detectable through simple and automated methods. Principal Component Analysis (PCA) was applied to experimental data in order to discriminate pasta samples according to their drying conditions. A limited number of volatile compounds including Maillard reaction and lipid-derived products (nonanal, hexanal, nonanoic acid, maltol and 2-furanmethanol) proved to be crucial in the differentiation of the samples. Therefore, these compounds could be used as pasta quality markers, alternatively to furosine, or as process markers to keep the drying treatment under control.