Comparison of traditional and flash pyrolysis of different carbon content silicon oxycarbides

This study is to understand the effect of carbon content on the pyrolysis behaviors and phase contents of silicon oxycarbides (SiOCs). Flash pyrolysis conditions, evolution of different SiOC phases, and free carbon types/amounts are compared for C-rich and less C-rich precursors. The C-rich system experiences the flash event at a much lower pyrolysis temperature with a much higher current density even though the internal temperatures at flash are very similar. SiC formation is more obvious for the C-rich samples along with a much higher carbon content under both flash and traditional pyrolysis conditions. The phase contents of SiO₂, SiC, and other SiOC intermediates can be calculated using a Gibbs energy minimization method, showing that the C-rich sample has more C-rich SiOC intermediates while the less C-rich sample has more Si-rich intermediates. This research provides a general framework in assessing the pyrolysis behaviors of different SiOC materials.     

Multiresponse Estimation With Special Application to Linear Systems of Differential Equations

We present a multiresponse estimation procedure for parameters of systems described by ? = As. The procedure features a generalized Gauss–Newton algorithm for optimizing the determinant criterion, efficient evaluation of the expectation function and its derivatives directly from the reaction network or compartment diagram, automatic determination of starting values, and eficient computational procedures for handling linear constraints on the responses.     

The Process of Activity and the Built Environment

Summary of some of the topics covered by the author under the ACSA-AMAX Research Fellowship, which he won in 1967.     

A New Curriculum

The challenge of understanding the many facets of design has been a central issue in attempting to computationally define design processes and knowledge. The historical progression of computers in design has been characterized by high aspirations repeatedly humbled by the complexity of design problems. Fundamental questions concerning the role and impact of computers in design should be re-examined in light of new developments in Computer-Aided Design (CAD) and Artificial Intelligence (AI), and the progressive understanding of design itself. At the heart of these issues must lie a mutual understanding of the respective traits of design and computation, and the balance of interaction between them.

In this paper two avenues, expressed in terms of mappings between design and computation, are explored with the intention of clarifying the relationship between the theories of design and computation. First, the relationship between models of the design process and computational search strategies is explored. Several paradigms (problem solving, puzzle making, and constraint satisfying), which demonstrate a breadth of approaches to modeling design, are presented along with their computational implications. Second, relationships between design knowledge and computational representation schemes are discussed. Emphasis is placed on drawing from cognitive and computational knowledge representation schemes to represent design knowledge. Finally, some thoughts on integrating these design models and knowledge representation schemes into computer systems to assist designers are discussed.     

Europe as Consumer of Exotic Biodiversity: Greek and Roman times

Landscapes at the edge of the city comprise vast areas that ‘lie fallow’, awaiting future urban development. During this time new landscape values evolve. It is argued that the complexity of urban fringe landscapes is not adequately considered either within landscape research or in the practice of spatial planning. A key to understanding landscapes at the inner urban fringe is to focus on landscape dynamics, and on the interactions between spatial plans and everyday activities. The study is divided into three parts. First, theoretical considerations about landscape dynamics and the character of the inner urban fringe are presented. Thereafter, the relationship between spatial planning and everyday places is analysed in a case-study area at the edge of the city of Malmö in southernmost Sweden. The case study demonstrates the complexity of landscape dynamics at the inner urban fringe, as well as problems regarding the handling of ephemeral and transitory aspects within spatial planning. The study concludes with a discussion concerning the importance of studies of landscape dynamics within landscape research.