Electrospun composite poly(lactic acid)/polyaniline nanofibers from low concentrations in CHCl3: Making a biocompatible polyester electro-active

Nanofibers of poly(lactic acid) (PLA) blended with polyaniline (PANi) were fabricated via electrospinning at much lower PLA concentrations (∼1wt%) in CHCl₃ than reported before using a more efficient technique of preparing the solutions. The polymer nanofibers had diameters in the range 10 nm–300 nm. Nanofibers prepared with a 3 wt% PLA/PANi solution were conducting and were used to fabricate a diode which was electrically characterized and exhibited a low turn-on voltage and a rectification ratio of 500. The device characteristics were analyzed using the standard thermionic emission model of a Schottky junction and yielded an ideality factor of 1.6 and a barrier height of 0.49 eV. Using a simple circuit, the diode was able to rectify a low frequency alternating current signal with an efficiency of 10%. The ability to engineer insulating PLA into nanofibers that are electro-active extends the range of applications of this biocompatible and biodegradable polyester to include electronic devices that have reduced toxicity.     

Thermodynamic cycle optimization for pyroelectric energy conversion in the thin film regime

Pyroelectric energy conversion is both simulated and realized on thin film lead zirconate titanate capacitors. The thermodynamics of the energy conversion cycle were explored, and the performance of the Brayton cycle was compared with the conventional Ericsson pyroelectric cycle. Cycle performance was examined using coefficients extracted from measured isothermal polarization hysteresis loops. It was found that the Brayton cycle is slightly more efficient than the Ericsson cycle over the range of temperatures tested and has significant efficiency improvements with increasing pyroelectric coefficients. The results from actual energy conversion cycles differed slightly from simulated performance, confirming the known challenges with synchronizing pyroelectric cycles with realistic thermal excitation. Finally, a one‐dimensional thermal transient model is used to explore the power conversion potential of thin film pyroelectrics. It is shown that the Brayton cycle has a significant performance advantage over the Ericsson cycle at higher operating frequencies. A power density of 8 mW/cm³ was obtained using the Brayton cycle for a thin film system at about 60 °C with an applied field of 5 V and stimulation frequency of 0.2 Hz. Copyright © 2017 John Wiley & Sons, Ltd.     

Neurofuzzy control of a low‐temperature desulphurization plant

Low‐temperature desulphurization (LTD) is a low‐cost alternative to conventional wet scrubbing for removing sulphur dioxide from flue gas produced by power generating plants. A problem in the design of conventional controllers to achieve and maintain process conditions for optimal desulphurisation is the lack of mathematical models to characterise the complex desulphurization process and unexpected environ mental disturbances. The aim of the work reported in this paper was to replace a skilled human operator who could successfully regulate the LTD plant through manipulation of low‐level controllers with a competitive neurofuzzy system, which possesses both the learning ability of neural networks and the structural transparency of fuzzy logic systems. A hierarchical control structure was adopted whereby the competitive neurofuzzy method was used at the top level for co‐ordinating actions of low‐level conventional controllers. This approach would considerably simplify the task of designing the control system and has been shown to yield high‐level controllers with performances at least equalling that of expert operators, as demonstrated in this paper. Copyright © 2001 John Wiley & Sons, Ltd.     

Reprint of “Safe places for pedestrians: Using cognitive work analysis to consider the relationships between the engineering and urban design of footpaths”

Footpaths provide an integral component of our urban environments and have the potential to act as safe places for people and the focus for community life. Despite this, the approach to designing footpaths that are safe while providing this sense of place often occurs in silos. There is often very little consideration given to how designing for sense of place impacts safety and vice versa. The aim of this study was to use a systems analysis and design framework to develop a design template for an ‘ideal’ footpath system that embodies both safety and sense of place. This was achieved through using the first phase of the Cognitive Work Analysis framework, Work Domain Analysis, to specify a model of footpaths as safe places for pedestrians. This model was subsequently used to assess two existing footpath environments to determine the extent to which they meet the design requirements specified. The findings show instances where the existing footpaths both meet and fail to meet the design requirements specified. Through utilising a systems approach for footpaths, this paper has provided a novel design template that can inform new footpath design efforts or be used to evaluate the extent to which existing footpaths achieve their safety and sense of place requirements.     

Regulation Theory,Global Competition Among Cities And Capital Embeddedness

This paper reviews the contribution of regulation theory to our understanding of urban development and its regulation by the state. The theory provides a useful instrument for convergence of politics, economics and geography in which the crucial questions of territoriality of local states and the embeddedness of capital can be considered. But there remains much to be explored both in the mode of development of the global economy over time, and in the relationship between global economic structures and local political institutions. The further development of regulation theory demands a reconceptualisation of power and the absorption of ecological/environmental and feminist discourses into the debates.     

Housing and Economic Development in Indian Country: Challenge and Opportunity

Global Warming: Climate Change: The IPCC Scientific Assessment J. T. Houghton, G. J. Jenkins, and J. J. Ephraums, editors. Cambridge University Press, Cambridge, UK, 1990. 305 pp. $34.95 (paperback).

Global Warming: Leaving Eden to Protect and Manage the Earth E. G. Nisbet. Cambridge University Press, Cambridge, UK, 1991. 358 pp. $14.95 (paperback).

Global Warming: Global Environmental Issues: A Climatological Approach David D. Kemp. Routledge, Chapman and Hall, London, 1990. 220 pp. $15.95 (paperback).

Global Warming: Global Climate Change and Life on Earth Richard L. Wyman, editor. Rout-ledge, Chapman and Hall, London, 1991. 282 pp. $24.95 (paperback).

Global Warming: Global Climate Change and California Joseph B. Knox and Ann Foley Scheuring, editors. University of California Press, Berkeley, 1992. 184 pp. $12.95 (paperback).

The Environment: Race and the Incidence of Environmental Hazards: A Time for Discourse Bunyan Bryant and Paul Mohai, editors. Westview Press, San Francisco, 1992. 251 pp. $32.00 (paperback).

The Environment: Sustaining the Earth John Young. Harvard University Press, Cambridge, MA, 1990. 202 pp. $10.95 (paperback).

The Environment: Rural Environmental Planning for Sustainable Communities Frederick O. Sargent, Paul Lusk, Jose A. Rivera, and Maria Varela. Island Press, Washington, DC, 1991. 254 pp. $24.95 (paperback).

The Environment: Environmental Politics: Public Costs, Private Rewards Michael S. Greve and Fred L. Smith, Jr., editors. Praeger, New York, 1992. 212 pp. $19.95 (paperback).

Planning and Its Subfields: Customer Service in Local Government: Challenges for Planners and Managers Bruce W. McClendon. Planners Press, American Planning Association, Chicago, 1992. 194 pp. $45.95, $34.95 (paperback).

Planning and Its Subfields: Reviving the American Dream: The Economy, the States and the Federal Government Alice M. Rivlin. Brookings Institution, Washington, DC, 1992. 196 pp. $15.95.

Planning and Its Subfields: Left Coast City: Progressive Politics in San Francisco, 1975-1991 Richard Edward DeLeon. University Press of Kansas, Lawrence, 1992. 239 pp. $35.00, $14.95 (paperback).

Planning and Its Subfields: The New Frontier for Land Policy: Planning and Growth Management in the States John M. DeGrove, with Deborah Miness. Lincoln Institute of Land Policy, Cambridge, MA, 1992. 176 pp. $18.95 (paperback).

Planning and Its Subfields: Magic Lands: Western Cityscapes and American Culture After 1940 John M. Findlay. University of California Press, Berkeley, 1992. 394 pp. $35.00.

Planning and Its Subfields: The Power of Maps Denis Wood. Guilford Press, New York, 1992. 248 pp. $35.00, $15.95 (paperback).

Planning and Its Subfields: Put up or Give Way: States, Economic Competitiveness, and Poverty John Sidor. Council of State Community Development Agencies, Washington, DC, 1991.243 pp. $20.00 (paperback).

Planning and Its Subfields: North American Free Trade: Assessing the Impact Nora Lustig, Barry P. Bosworth, and Robert Z. Lawrence, editors. Brookings Institution, Washington, DC, 1992. 274 pp. $28.95, $10.95 (paperback).

Briefly Noted: Electronic Byways: State Policies for Rural Development Through Telecommunications Edwin B. Parker and Heather Hudson, with Don A. Dillman, Sharon Strover, and Frederick Williams. Westview, Boulder, CO, 1992. 306 pp. $57.50, $18.85 (paperback).

Briefly Noted: Credit Where It's Due: Development Banking for Communities Julia Ann Parzen and Michael Hall Kieschnick. Temple University Press, Philadelphia, PA, 1992. 275 pp. $29.95.

Briefly Noted: Reclaiming the Past Landmarks of Women's History Page Putnam Miller, editor. Indiana University Press, Bloomington, 1992. 232 pp. $35.00.

Briefly Noted: Renewing Cities Ross J. Gittell. Princeton University Press, Princeton, NJ, 1992. 232 pp., $39.50.

Briefly Noted: Regions Reconsidered: Economic Networks, Innovation, and Local Development in Industrialized Countries Edward Bergman, Gunther Maier, and Franz Todtling, editors. Mansell, London, 1991. 312 pp. $80.00.

Briefly Noted: Defense, Welfare and Growth: Perspective and Evidence Steve Chan and Alex Mintz, editors. Routledge, Chapman and Hall, New York, 1992. 248 pp. $59.95.

Briefly Noted: The Changing Image of the City: Planning for Downtown Omaha, 1945-1973 Janet R. Daly-Bednarek. University of Nebraska Press, Lincoln, 1992. 292 pp. $37.50.