Ecological footprints and sustainable urban form

This paper presents the results of a four-yearresearch project (1997–2001) entitled `Housingas a basis for sustainable consumption'. Theoverall aim was to obtain more empirical andtheoretical knowledge about the connectionbetween physical urban planning and householdconsumption. This knowledge provides a platformfor discussing principles and practices forsustainable urban development.This project was based on two main assumptions.First, it was suggested that the significantand increasing environmental damage due toprivate household consumption presents a majorchallenge in achieving sustainable development.Second, a large part of this consumption appears to be influenced by our physical livingsituation, i.e., the way we design and locateour houses. This also applies to energy use forheating and technical appliances, transport,and even to the considerable amount ofequipment that is needed for householdoperation, redecoration and maintenance. Withrespect to transport, the study team includedboth everyday travel and leisure-time journeysin this research. While everyday trips such astravelling to work, shopping and taking thechildren to school are strongly influenced bythe living situation of the household, thismight also be true for leisure-time travel.Based on two large surveys in the Norwegiantowns of Greater Oslo and Førde, the studyteam collected data on housing-relatedconsumption from 537 households. Ecological Footprinting was then used asan analytical tool to analyse the environmentalconsequences of this consumption. Theseecological footprint analyses suggest thatsustainable urban development points towardsdecentralized concentration, i.e.,relatively small cities with a high density andshort distances between the houses andpublic/private services.     

MOULDS FOR MAGNESITE,CHROME AND SILICA BRICK1

Shrinkage. —Determination of allowance for shrinkage in mould manufacture is of prime importance. Design comes next. Types of Moulds. —Slip moulds including the open slip and vent bottom types, steel slip liner moulds, and the wooden knock-down screw mould. Materials Used. —Soft steel, cold rolled steel, galvanized iron and hard woods. Moulding Tools. —The slicker, short scoop, smacker, putty knife, rammer and hammer. Manufacture of Moulds. —Relation to the manufacture of all kinds of brick made from these special refractory materials. The treatment of each type of mould includes materials and method of manufacture, the materials and kinds of brick, the manufacture of which it is best suited, together with the manipulation best suited to turning out a uniformly good product. Correction of mould faults and suggestions for overcoming difficulties encountered in moulding brick find their place wherever the discussion of the various moulds and operations suggests any of the common troubles of the moulder.     

Solid‐State Conversion Reaction to Enhance Charge Transfer in Electrochromic Materials

Interface engineering has attracted great interest and is essential for the fabrication of thin‐film devices, such as smart windows. In this study, a solid‐state conversion reaction for the development of an interlayer enriched with lithium peroxide (Li₂O₂) is presented for an electrochromic device. We demonstrate that efficient lithium insertion and electron transport can be achieved by the inclusion of a Li₂O₂‐rich interlayer between an active electrochromic material and Li ion solid‐state electrolyte layer. The presence of a Li₂O₂‐rich interlayer enhances electrochromic efficiency, kinetics, optical contrast, and bleached‐state transparency in a nickel oxide‐based electrochromic thin film. This work opens up new opportunities to enhance the functionalities of thin‐film devices by solid‐state conversion reactions.     

X‐Ray Spectroscopic Investigation of Chlorinated Graphene: Surface Structure and Electronic Effects

Chemical doping of graphene represents a powerful means of tailoring its electronic properties. Synchrotron‐based X‐ray spectroscopy offers an effective route to investigate the surface electronic and chemical states of functionalizing dopants. In this work, a suite of X‐ray techniques is used, including near edge X‐ray absorption fine structure spectroscopy, X‐ray photoemission spectroscopy, and photoemission threshold measurements, to systematically study plasma‐based chlorinated graphene on different substrates, with special focus on its dopant concentration, surface binding energy, bonding configuration, and work function shift. Detailed spectroscopic evidence of C–Cl bond formation at the surface of single layer graphene and correlation of the magnitude of p‐type doping with the surface coverage of adsorbed chlorine is demonstrated for the first time. It is shown that the chlorination process is a highly nonintrusive doping technology, which can effectively produce strongly p‐doped graphene with the 2D nature and long‐range periodicity of the electronic structure of graphene intact. The measurements also reveal that the interaction between graphene and chlorine atoms shows strong substrate effects in terms of both surface coverage and work function shift.     

Crack Tip Opening Displacement in atomistic modeling of fracture of silicon

We analyze the fracture of single crystal silicon simulated by atomistic modeling with ReaxFF first principles based reactive force field. The simulations are performed at three temperatures: 500 K, 800 K and 1200 K, capturing both brittle and ductile behavior for the selected crystallographic orientation with (1 0 0) as the fracture plane. Three failure mechanisms are observed: bond breaking, amorphization and emission of dislocations. We demonstrate that the Crack Tip Opening Displacement (CTOD) gives a realistic estimate of the fracture toughness of brittle fracture, linking continuum mechanics fracture theory with the direct crack tip atomistic approach. We discuss the physics based mechanisms of failure in silicon in view of the CTOD measurements.     

A THERMODYNAMIC MIXED-SOLID ASPHALTENE PRECIPITATION MODEL

A simple model for the prediction of asphaltene precipitation is proposed. The model is based on an equation of state and uses standard thermodynamics, thus assuming that the precipitation phenomenon is a reversible process. The solid phase is treated as an ideal multicomponent mixture. An activity coefficient model based on the athermal Flory-Huggins expression was included to account for solid phase non-ideality, but was found to have little effect on the results. Only a fraction of each of the heaviest components are considered potentially solid forming. This approach is based on the assumption, that out of the total PNA composition of a crude, the asphaltenes and resins are mainly aromatic-naphtenic in their nature. The predictions shows the correct qualitative behavior with respect to temperature and pressure, but due to lack of data the model was not evaluated quantitatively with respect to these effects     

Fast fourier transform processors using Gaussian residue arithmetic

Residue arithmetic using moduli which are Gaussian primes is suggested as a method for computing the fast Fourier transform (FFT). For complex operations, a substantial savings in hardware and time over residue arithmetic using real moduli can be obtained using complex moduli. Gaussian residue arithmetic is discussed and methods for conversion into and out of the complex residue representation are developed. This representation lends itself to table-driven computation, allowing very low latency designs to be developed. A 64-point Cooley-Tukey style processor and a 60-point Rader-Winograd style processor using this technique are described and compared. Hardware savings are realized by approximating the rotations necessary to perform the FFT by small complex integers and by scaling the results of the computation at an intermediate point. It is shown that further hardware reductions can be made by developing custom integrated circuits at the expense of latency.     

Kairomones and their use for management of entomophagous insects: III. Stimulation ofTrichogramma achaeae,T. pretiosum,andMicroplitis croceipes with host-seeking stimuli at time of release to improve their efficiency

Frass from larvae of the corn earworm,Heliothis zea (Boddie) and scales fromH. zea moths (that are known to contain the host-seeking stimulus, tricosane) stimulate and orient host-seeking activity in femaleMicroplitis croceipes (Cresson), a larval parasite ofH. zea, andTrichogramma spp., egg parasites ofH. zea. When larval frass, moth scales, and tricosane were used as sign stimuli (releasers) forM. croceipes, T. pretiosum (Riley), andT. achaeae Nagaraji and Nagarkatti, respectively, at time of their release from laboratory containers, parasite performance improved, resulting in significantly increased rates of parasitization over that of unstimulated parasites. Stimulation ofM. croceipes with larval frass had an overriding effect on this parasite's innate tendency to disperse upon release, thereby increasing the numbers remaining and prolonging their retention in the target area. Supplying the appropriate host-seeking stimuli to these 3 hymenopterous parasites ofH. zea at time of their release to improve their efficiency greatly increases the probability of their effective utilization in pest management systems.