Microbial hazards related to rice sprouting

The microbiology of rice seeds selected for commercial production of sprouts was studied. Bacteria were numerous but generally nonpathogenic: almost all were gram-negative rods, predominantly pseudomonads. There were also several enterobacteria, in particular Enterobacter and Klebsiella species. Escherichia coli was present in very few samples and its serotype was not enteropathogenic. Moulds were infrequent. Storage of seeds under laboratory conditions did not greatly modify the composition of the microflora but counts decreased with time. When grains were stored in a cold room, the microflora remained almost unchanged quantitatively and qualitatively. After 2 days of germination, mesophilic aerobic plate counts increased by about 2 log cycles; thermotolerant coliforms and faecal enterococci increased by up to 6 log cycles. No foodborne pathogens were detected on sprouts. Moreover, both dry seeds and sprouts were negative for aflatoxins. Experiments with artificially inoculated seeds showed that Bacillus cereus and Listeria sp. could develop without any antagonistic effect from the background flora of germinating rice.     

A K-band bi-phase modulator MMIC for UWB application

A 24-GHz-band, three-dimensional microwave monolithic integrated circuit (MMIC) bi-phase modulator, that is a combination of an active 0//spl pi/ splitter and a SPDT switch, is proposed and demonstrated. Comparing conventional K-band bi-phase modulators, this modulator is broadband, significantly MMIC compatible, and shrinks its chip area. A fabricated bi-phase modulator exhibits an area of 1.0/spl times/0.7mm/sup 2/ and a 1-dB bandwidth of nearly 10GHz. The SPDT switch is optimized in control-gate's time constant so that a very clear bi-phase modulated waveform can be generated from 1Gbps PN code. The insertion loss and the phase imbalance are 6.4 dB+/-0.6 dB and within 10/spl deg/, respectively, between 22GHz and 32GHz.     

Scalable Metadata Management Through OSD+ Devices

We present the design and implementation of both an enhanced new type of OSD device, the OSD+ device, and a metadata cluster based on it. The new OSD+ devices support data objects and directory objects. Unlike “data” objects, present in a traditional OSD, directory objects store file names and attributes, and support metadata-related operations. By using OSD+ devices, we show how the metadata cluster of the Fusion Parallel File System (FPFS) can effectively be managed by all the servers in a system, improving the performance, scalability and availability of the metadata service. We also describe how a directory with millions of files, and accessed by thousands of clients at the same time, is efficiently distributed across several servers to provide high IOPS rates. The performance of our metadata cluster based on OSD+s has been evaluated and compared with that achieved by Lustre. The results show that our proposal obtains a better throughput than Lustre when both use a single metadata server, easily getting improvements of more than 60–80%, and that the performance scales with the number of OSD+s. They also show that FPFS is able to provide a sustained throughput of more than 70,000 creates per second, and more than 120,000 stats per second, for huge directories on a cluster with just 8 OSD+s.     

Three-dimensional MMIC technology for low-cost millimeter-waveMMICs

This paper highlights the key advantages of the three-dimensional (3-D) MMIC technology in the millimeter-wave frequency band and describes recently developed compact 3-D MMICs on GaAs and Si substrates. The 3-D MMIC technology offers high integration levels, compactness, simple design procedures, and short fabrication turn-around time, resulting in millimeter-wave MMICs at greatly reduced cost. This paper also proposes a new methodology for MMIC development based on 3-D/multilayer MMIC technology that accelerates the cost reduction of millimeter-wave MMICs. The new technology achieves compact and highly integrated millimeter-wave MMICs that are extremely cost effective     

K-band 3-D MMIC low noise amplifier and mixer using TFMS lines with ground slit

Three-dimensional (3-D) microwave monolithic integrated circuit (MMIC) technology, that incorporates slits in the ground metal, was applied to K-band low noise amplifier (LNA) and I/Q mixer to provide a low cost solution for various K-band receivers such as for P-to-P radio, WLAN, and UWB sensors. The LNA incorporates a quasicoplanar stub in the input-matching network, improving the noise figure by 1 dB. This low-noise amplifier (LNA) exhibits a noise figure of 2.5 dB with an associated gain of 16 dB and an area of 0.75/spl times/0.65 mm/sup 2/. The I/Q resistive mixer incorporates a broadside 3-dB coupler with a 22-/spl mu/m-wide slit in the ground metal beneath the coupled thin-film micro-strip (TFMS) lines (patent pending). The insertion loss of the 3 dB coupler is 0.75 dB. The I/Q mixer exhibits a conversion loss of less than 14 dB at 0.1-2.0GHz IF frequencies for 2-dBm local input power. These LNA and mixer potentially make it easier to integrate receiver functions in a die.     

Miniaturised 45° power divider using three-dimensional MMICtechnology

A miniaturised 45° power divider using three-dimensional MMIC technology is described. The divider comprises stacked thin-film microstrip lines that sandwich a ground plane between them. It has an area of only 0.43 mm², and it exhibits a coupling of 4.5±0.2 dB and a phase difference of 45±1° from 28 to 33 GHz     

Analysis of balanced active doubler for broad-band operation - thefrequency-tuning concept

A comprehensive analysis of an active balanced frequency doubler is described and proposed as a new concept: tuning the center frequency at which the doubler exhibits its highest performance to extend the usable bandwidth of the device. The concept is validated using a fabricated V-band pseudomorphic high electron-mobility transistor frequency doubler. For this device, a substantial improvement in the usable bandwidth (more than double) is achieved, demonstrating that the proposed concept is particularly suitable for the realization of high spectral purity and widely tunable V-band frequency sources     

Improvement of the design of 180° rat-race hybrid

An innovative and simple design for a 180° rat-race hybrid is proposed which has a substantially improved phase shift characteristic over a large bandwidth compared with that of a conventional rate-race hybrid. The proposed hybrid has been fabricated with a three-dimensional technology to benefit from a high level of integration. It exhibits a bandwidth of 31% from 28.8 to 39.4 GHz with -15 dB input and output matching, a coupling loss of 4.6 dB with a power dividing balance better than 1.1 dB, and a phase balance better than 2