Analytical pyrolysis as a tool for the study of plastic coals

The technique of analytical pyrolysis has been used to characterize 40 similar mid-rank western Kentucky coals of widely differing ASTM Gieseler plasticity. Certain pyrolysis/g.c. variables were shown to correlate well with both ASTM Gieseler and isothermal plasticity. Highly plastic coals were shown to exhibit certain characteristic peaks in the 450 °C pyrogram which were absent in the pyrogram of the non-plastic coals. Two coals, representing the two extremes in plasticity, were selected for further study. After extraction with solvents such as DMF the characteristic peaks were absent in the 450 °C pyrogram of the extraction residue of the highly plastic coal. These peaks were also shown to decrease with increasing severity of air oxidation of the plastic coal. This technique appears to be a useful tool for the analysis of mid-rank plastic coals and supports the view that the substances contained in the bitumen fraction of these coals are involved in the development of the plastic state.     

The Present Status and Potential of Kraft Lignin-Phenol-Formaldehyde Wood Adhesives

Kraft lignin (KL), a phenolic polymer formed during the kraft pulping process, is presently burned as a low value fuel. For decades, researchers have attempted to use KL as an inexpensive substitute for phenol in phenol-formaldehyde (PF) resins, but no one has produced a commercially satisfactory KL-PF resin. This paper reviews the literature on the present status of KL-PF adhesives and makes recommendations on needed research.

Kraft lignin solutions are complex mixtures which have broad molecular weight distributions, high viscosities, relatively low reactivities, and low solubilities. Attempts to overcome these inherent problems include methylolation of lignin to improve reactivity, the use of co-solvents to improve solubility, and ultrafiltration to yield more homogeneous molecular weight fractions. Future research efforts need to focus on understanding the fundamental chemical and physical properties of kraft lignin and its resins. The search for an economic lignin-based wood adhesive should continue.     

Upgrading of aspen poplar wood oil over HZSM-5 zeolite catalyst

Thermally fractionated components of an oil prepared by the liquefaction of aspen poplar wood have been upgraded using a HZSM-5 zeolite catalyst to yield products rich in benzene, toluene, xylenes and higher molecular weight aromatics. The effect of reactor temperatures on the relative abundance of these products has been studied.     

45 GHz self-pulsation with narrow linewidth in quantum dot Fabry-Perot semiconductor lasers at 1.5 /spl mu/m

Self-pulsation at 45 GHz repetition frequency has been demonstrated in 1.5 /spl mu/m monolithic single-section quantum dot Fabry-Perot semiconductor lasers without saturable absorber. The mode-beating exhibits a narrow linewidth below 100 kHz, demonstrating high phase correlation between these modes. Such modelocked lasers open ways to low timing-jitter components for clock recovery or millimetre-wave generation in wireless transmission applications.     

Using Bandwidth-Space Partitioning to Improve Cell Coverage and Near-Far Unfair Access Problem in a Noise-Limited CDMA Cellular Network

This paper concerns CDMA cellular networks equipped with conventional matched filter receivers. For this type of cellular networks, two problems exist. One is the inverse relationship between the coverage and capacity, and the other one is the near-far unfair access problem. To resolve these two problems, a bandwidth-space partitioning technique is adopted. Several admission control schemes based on the bandwidth-space partitioning technique are proposed, and their performances are evaluated based on the simulation.Shih-Tsung Yang received his B.S. (1989) and M.S. (1991) degrees in electrical engineering from the National Taiwan University, and Ph.D. (1999) degree in electrical and computer engineering from University of Maryland, College Park.From 1999 to 2000, he was with SBC Technology Resourtces, Inc. where he was involved in the network architecture design for the ATM based networks. From November 2000 to May 2003, he was with Transilica/Microtune where he was involved in the design of Baseband and RF for the wireless communications. Since May 2003, Dr. Yang is now with Genesys Logic, Inc. where he is responsible for the baseband design of the WLAN and Ethernet.Dr. Yang’s research interests are in the area of Digital Communications, Communication networks and signal processing. E-mail: thomas.yang@genesyslogic.com.twAnthony Ephremides received his B.S. degree from the National Technical University of Athens (1967), and M.S. (1969) and Ph.D. (1971) degrees from Princeton University, all in Electrical Engineering. He has been at the University of Maryland since 1971, and currently holds a joint appointment as Professor in the Electrical Engineering Department and in the Institute of Systems Research (ISR) of which he is a founding member. He is co-founder of the NASA Center for Commercial Development of Space on Hybrid and Satellite Communications Networks established in 1991 at Maryland as an off-shoot of the ISR. He served as Co-Director of that Center from 1991 to 1994.He was a Visiting Professor in 1978 at the National Technical University in Athenas, Greece, and in 1979 at the EECS Department of the University of California, Berkeley, and at INRIA, France. During 1985-1986 he was on leave at MIT and ETH in Zurich, Switzerland. He was the General Chairman of the 1986 IEEE Conference on Decision and Control in Athens, Greece and of the 1991 IEEE International Symposium on Information Theory in Budapest, Hungary. He also organized two workshops on Information theory in 1984 (Hot Springs, VA) and in 1999 (Metsovo, Greece). He was the Technical Program Co-Chair of the IEEE INFOCOM in New York City in 1999 and of the IEEE International Symposium on Information theory in Sorrento, Italy in 2000. He has also been the Director of the Fairchild Scholars and Doctoral Fellows Program, an academic and research partnership program in Satellite Communications between Fairchild Industries and the University of Maryland. He won the IEEE Donald E. Fink Prize Paper Award (1992) and he was the first recipient of the Sigmobile Award of the ACM (Association of Computer Machinery) for contributions to wireless communications in 1997. He has been the President of the Information Theory Society of the IEEE (1987) and has served on its Board of Governors almost continuously from 1981 until the present. He was elected to the Board of Directors of the IEEE in 1989 and 1990. Dr. Ephremides has authored or co-authored over 100 technical journal papers and 300 technical conference presentations. He has also contributed chapters to several books and edited numerous special issues of scientific journals. He has also won awards from the Maryland Office of Technology Liaison for the commercialization of products and ideas stemming from his research. He has served on the Editorial Boards of the IEEE Transactions on Automatic Control, IEEE Transactions on Information theory, the Journal of Wireless Networks, and the International Journal of Satellite Communications.He has been the Dissertation Supervisor of over twenty Ph.D. students who now hold prominent positions in academia, industry, and research labs. He is the founder and President of Pontos, Inc., a Maryland company that provides technical consulting services, since 1980.Dr. Ephremides’ interests are in the areas of communication theory, communication systems and networks, queueing systems, signal processing, and satellite communications. His research has been continuously supported since 1971 by NSF, NASA, ONR, ARL, NRL, NSA, and Industry. E-mail: tony@eng.umd.edu     

An integrative conceptual framework of disability: New directions for research.

Advances in research on disability and rehabilitation are essential to creating equal opportunity, economic self-sufficiency, and full participation for persons with disabilities. Historically, such initiatives have focused on separate and specific areas, including neuroscience, molecular biology and genetics, gerontology, engineering and physical sciences, and social and behavioral sciences. Research on persons with disabilities should examine the broader context and trends of society that affect the total environment of persons with disabilities. This article examines the various disability paradigms across time, assessing the relative contribution of the socioecological perspective in guiding research designed to improve the lives of persons with disabilities. The authors recommend new research directions that include a focus on life span issues, biomedicine, biotechnology, the efficacy and effectiveness of current interventions, an emphasis on consumer-driven investigations within a socioecological perspective of disability, and the implications for research and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crushing behaviour of the energy absorbing 'tensor skin' panels

ABSTRACT Research results concerning the simulation of the crushing behaviour of composite systems with energy absorption characteristics are presented in the present work. The study is focused on the ‘tensor skin’ concept, an energy absorbing composite system that was originally developed to improve the crashworthiness of helicopters under water impact and which is promising for utilization in the construction of the lower part of composite fuselage aircraft. The ‘tensor skin’ concept comprises a folded or corrugated composite construction, which upon loading unfolds by forming ‘plastic hinges’, leading to an increase in the load bearing capability of the structure. The numerical modelling issues and the critical aspects of the simulation are discussed. Verification of the numerical simulation procedure is performed by experimental work. The experimental results utilized to assess and validate the numerical procedure were derived within the European Research Project ‘Design for Crash Survivability – CRASURV’ (BRITE – Aeronautics Area). The results of the simulations are generally in good agreement with experimental data.