Monoclinic Zirconia Bodies by Thermoplastic Ceramic Extrusion

Two ultrafine, undoped ZrO₂ powders with median primary particle sizes of 9 and 25 nm were used to prepare ceramic suspensions for thermoplastic extrusion. The organic vehicle consisted of an industrial-grade poly(ethylene- co -vinyl acetate) (EVA) or polyethylene (PE-HD) and decanoic acid as a dispersing agent. The powder volume loadings achieved were 44% and 52% by volume for the two powders, respectively. The amount of dispersant needed was calculated from a new model based on available chemisorption sites on the powder surface. Mixing and extrusion were conducted using a conventional modular plastic processing unit. Green bodies were dewaxed up to 450°C in an inert atmosphere and sintered to full density in air at 1060° and 1100°C, respectively. Analysis of the ceramic phase content and the microstructure of the bodies is presented.     

Impact of the access network topology on the handoff performance

Micromobility protocols such as Cellular IP, Hawaii and Hierarchical Mobile IP are developed to solve problems of high handoff latency and control overhead, which occur when Mobile IP is used in combination with frequent handoffs. Up to now, tree access network topologies are considered to evaluate the protocol performance. However, for reasons of robustness against link failures and load balancing, extra uplinks and mesh links in the topology are desired. This article makes a classification of several topology types and gives a model that points out to which extent the topology influences the protocol performance in terms of handoff latency and handoff packet loss. Simulations confirm the results calculated by the model. Performance metrics such as load balancing, end-to-end delay and robustness against link failures are also evaluated. The study points to several shortcomings of the existing micromobility protocols for different topology types. Several aspects of the studied handoff schemes, their advantages and drawbacks are identified. L. Peters is a Research Assistant of the Fund for Scientific Research – Flanders (F.W.O.-V., Belgium) Liesbeth Peters was born in Temse, Belgium, in 1978. She received her Master of Science degree in Electrotechnical Engineering from Ghent University, Gent, Belgium in 2001. Since August 2001, she has been working as a doctoral researcher with the Department of Information Technology (INTEC) of the Faculty of Applied Sciences, Ghent University, where she joined the Broadband Communications Networks Group. Since October 2002, she works there as a research assistant of the Fund for Scientific Research—Flanders (F.W.O.-V., Belgium). Her current research interests are in broadband wireless communication and the support of IP mobility in wired cum wireless networks. Ingrid Moerman was born in Gent, Belgium, in 1965. She received the degree in Electro-technical Engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1987 and 1992, respectively. Since 1987, she has been with the Interuniversity Micro-Electronics Centre (IMEC) at the Department of Information Technology (INTEC) of the Ghent University, where she conducted research in the field of optoelectronics. In 1997, she became a permanent member of the Research Staff at IMEC. Since 2000 she is part-time professor at the Ghent University. Since 2001 she has switched her research domain to broadband communication networks. She is currently involved in the research and education on broadband mobile & wireless communication networks and on multimedia over IP. Her main research interests related to mobile & wireless communication networks are: adaptive QoS routing in wireless ad hoc networks, personal networks, body area networks, wireless access to vehicles (high bandwidth & driving speed), protocol boosting on wireless links, design of fixed access/metro part, traffic engineering and QoS support in the wireless access network. Ingrid Moerman is author or co-author of more than 300 publications in the field of optoelectronics and communication networks. Bart Dhoedt received a degree in Engineering from the Ghent University in 1990. In September 1990, he joined the Department of Information Technology of the Faculty of Applied Sciences, University of Ghent. His research, addressing the use of micro-optics to realize parallel free space optical interconnects, resulted in a PhD degree in 1995. After a 2 year post-doc in opto-electronics, he became professor at the Faculty of Applied Sciences, Department of Information Technology. Since then, he is responsible for several courses on algorithms, programming and software development. His research interests are software engineering and mobile & wireless communications. Bart Dhoedt is author or co-author of more than 100 papers published in international journals or in the proceedings of international conferences. His current research addresses software technologies for communication networks, peer-to-peer networks, mobile networks and active networks. Piet Demeester finished his PhD thesis at the Department of Information Technology (INTEC) at the Ghent University in 1988. At the same department he became group leader of the activities on Metal Organic Vapour Phase Epitaxial growth for optoelectronic components. In 1992 he started a new research group on Broadband Communication Networks. The research in this field resulted in already more than 300 publications. In this research domain he was and is a member of several programme committees of international conferences, such as: ICCCN, the International Conference on Telecommunication Systems, OFC, ICC, and ECOC. He was Chairman of DRCN’98. In 2001 he was chairman of the Technical Programme Committee ECOC’01. He was Guest Editor of three special issues of the IEEE Communications Magazine. He is also a member of the Editorial Board of the Journals “Optical Networks Magazine” and “Photonic Network Communications”. He was a member of several national and international PhD thesis commissions. Piet Demeester is a member of IEEE (Senior Member), ACM and KVIV. His current research interests include: multilayer networks, Quality of Service (QoS) in IP-networks, mobile networks, access networks, grid computing, distributed software, network and service management and applications (supported by FWO-Vlaanderen, the BOF of the Ghent University, the IWT and the European Commission). Piet Demeester is currently full-time professor at the Ghent University, where he is teaching courses in Communication Networks. He has also been teaching in different international courses.     

Color‐gamut expansion in CRTs

Abstract— This paper describes the architecture for a color picture tube (CPT), which enables a cost‐effective expansion of the color gamut. Besides a gamut expansion based on application of more‐saturated phosphors in the present three‐primary system, four‐ and five‐primary systems are described. Gun‐pitch modulation allows the application of a conventional electron gun for both a four‐ and five‐primary CRT. In these systems, the mask and matrix transmissions need to be reduced to maintain color purity. From this point of view, a five‐primary CRT is unrealistic. Two four‐primary CRTs are evaluated in more detail. But, here, the total anode current to generate white has to be increased substantially because of the reduced mask and matrix transmissions. Nonetheless, in this paper it is argued that with one of the four‐primary CRTs more‐saturated yellow colors can be displayed at 85% of the display luminance of a conventional system without loss of perceived sharpness.     

A Low Power DSP Engine for Wireless Communications

This paper describes the architecture and the performance of a new programmable 16-bit Digital Signal Processor (DSP) engine. It is developed specifically for next generation wireless digital systems and speech applications. Besides providing a basic instruction set, similar to current day 16-bit DSP's, it contains distinctive architectural features and unique instructions, which make the engine highly efficient for compute-intensive tasks such as vector quantization and Viterbi operations. The datapath contains two Multiply-Accumulate units and one ALU. The external memory bandwidth is kept to two data busses and two corresponding address busses. Still, the internal bus network is designed such that all three units are operating in parallel. This parallelism is reflected in the performance benchmarks. For example, an FIR filter of N taps will take N/2 instruction cycles compared to N for a general purpose 16-bit DSP, and it will require only half the number of memory accesses of a general purpose DSP. This efficiency is reflected in the very low MIPS requirement to implement cellular standards.     

Changes in viscosity and pectolytic enzymes of tomato and strawberry juices processed by high-intensity pulsed electric fields

The effects pulse frequency (50–250 Hz), pulse width (1.0–7.0 μs) and polarity (monopolar or bipolar) of high-intensity pulsed electric field treatments (35 kV cm⁻¹ and 1000 μs) on viscosity and the pectin methylesterase (PME) and polygalacturonase (PG) activities were evaluated using a response surface methodology. Second-order expressions were accurate enough to fit experimental results. Tomato juice apparent viscosity increased within the range of the assayed conditions, achieving the highest values at 250 Hz and 7.0 μs in bipolar mode. At the same conditions the lowest residual PME (RA_PME = 10%) and PG (RA_PG = 45%) activities were observed in the juice. Apparent viscosity of strawberry juices slightly rose when frequencies higher than 100 Hz and 1-μs monopolar pulses were applied to the juice. Treatments causing the greatest increase in strawberry juice apparent viscosity also led to the lowest RA_PME (10%) and RA_PG (75%) values. In contrast, viscosity loss was promoted under the rest of assayed HIPEF conditions despite the low RA_PME values (<20%) achieved. Moreover, RA_PG did not decrease below 75% throughout the range of studied conditions.     

A method for the identification and quantitative investigation of denatured proteins in mixtures based on computer comparison of amino-acid patterns

Summary A procedure is described in which stepwise regression is adapted to permit comparison of the amino-acid pattern from a composite sample with those of simple substances arranged in an easily accessible data bank. The computer program automatically selects from the bank those proteins whose amino-acid patterns best correspond to that of the sample, and calculates the proportion of the proteins contained in the mixture.The procedure is applicable to food analytical problems that involve the identification and determination of proteins in mixtures, and also to situations in which the properties of the proteins have been altered by denaturation or enzymatic degradation. The determination is limited to 3–4 proteins in the mixture.

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Identifizierung und quantitative Bestimmung einzelner Proteine in Mischungen von denaturierten Proteinen mit Hilfe ihrer Aminosäauremuster

Zusammenfassung Mit Hilfe einer stufenweisen Regressionsberechnung konnen Aminosäu-renmuster eines zusammengesetzten Proteins mit einfachen Proteinen verglichen werden. Mit dieser Berechnung werden aus einer Sammlung von Vergleichsproteinen automatisch solche Proteine ausgewählt, deren Aminosäurenmuster am besten zu der der Probe paßt. Gleichzeitig können dadurch die Verhältnisse der verschiedenen Proteine in der Mischung berechnet werden. Durch these Arbeitsweise konnen weiterhin bei nahrungsanalytischen Problemen Proteine in Mischungen identifiziert and quantitativ erfaßt werden, selbst worn die Proteine denaturiert oder enzymatisch abgebaut sind, jedoch ist das Verfahren auf 3–4 Proteine in der Mischung begrenzt.

     

Construction of Bézier points of quadrilaterals from those of triangles

A simple algorithm is given which calculates the Bézier points of a surface over a quadrangle from the given generalized Bézier points of the surface over a triangle. An example is added.     

Effect of motivational context on conspecific song discrimination by brown-headed cowbirds (Molothrus ater).

Two experiments to examine the effects of motivational context on the perception of conspecific song by cowbirds were conducted. In the 1st experiment, sexual displays were elicited from females by playback of normal song and rearranged sequences of the component phrases. In a 2nd experiment, male and female cowbirds discriminated among the same songs in a food-rewarded operant procedure. In a sexual context, the birds were sensitive to both the beginning and end phrases of normal song, whereas in a food context, the birds were more sensitive to the beginning of normal song. In both experiments, 1-phrase songs were better discriminated from normal song than 2-phrase songs, and there was no effect of phrase order on discrimination. Similarities and differences in the results of the 2 experiments suggest that some aspects of cowbird song perception remain constant across motivational contexts, whereas others are unique to particular motivational contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)