Optimised anaerobic treatment of house-sorted biodegradable waste and slaughterhouse waste in a high loaded half technical scale digester.

Anaerobic co-digestion of organic wastes from households, slaughterhouses and meat processing industries was optimised in a half technical scale plant. The plant was operated for 130 days using two different substrates under organic loading rates of 10 and 12 kgCOD.m(-3).d(-1). Since the substrates were rich in fat and protein components (TKN: 12 g.kg(-1) the treatment was challenging. The process was monitored on-line and in the laboratory. It was demonstrated that an intensive and stable co-digestion of partly hydrolysed organic waste and protein rich slaughterhouse waste can be achieved in the balance of inconsistent pH and buffering NH4-N. In the first experimental period the reduction of the substrate COD was almost complete in an overall stable process (COD reduction >82%). In the second period methane productivity increased, but certain intermediate products accumulated constantly. Process design options for a second digestion phase for advanced degradation were investigated. Potential causes for slow and reduced propionic and valeric acid degradation were assessed. Recommendations for full-scale process implementation can be made from the experimental results reported. The highly loaded and stable codigestion of these substrates may be a good technical and economic treatment alternative.     

Study of a BGO calorimeter using electron and hadron beams from 1 to 50 GeV

A calorimeter of 25 bismuth germanate (BGO) crystals equipped with silicon photodiode readout has been tested at the CERN SPS in the energy range 1–50 GeV. The response for electrons has been shown to be linear in this energy range and the rms resolution obtained ( ) is approximately 1%, for E > 4 GeV. The electron/pion separation was found to be better than 1:500 in the energy range 1–20 GeV. Data on lateral and longitudinal shower development were compared with the results of a Monte Carlo simulation using the SLAC-EGS program and found to be in good agreement.     

April in Paris: signs of artificial life along the Seine

What if every public space and surface were transformed into an interactive experience - capturing our movements, gestures, sounds and actions and using these to produce new sounds, images, text and actions? Bus stops could come alive and talk back, advertisements could look back at you and talk to you and public park robotic devices could play games with you. Will public places eventually become our social barometer as well as director? Will billboards display the populace's discourse? The author look at some special streets in France where the city is literally alive with art and explores what it might mean for us to live in a world of artistic interactivity.     

Stream Classification System Based on Susceptibility to Algal Growth in Response to Nutrients

We developed a stream classification system that is based on stream’s susceptibility to algal growth using a two-step approach. The model portrays algal biomass as a result of stream’s response to nutrient concentrations and the response is governed by various stream factors. In the first step, a nutrient-chlorophyll a relationship was developed to characterize nutrient’s effects on algal biomass. Residuals of the relationship were attributed to stream’s susceptibility to algal growth in response to nutrients and referred to as “observed” susceptibility. In the second step, conditions of other contributing factors were used to explain the variation in the residuals and the developed relationship was used to generate “predicted” susceptibility. Existing data compiled from various monitoring projects of Illinois streams and rivers were used to illustrate the approach. Streams were classified into three (high, medium, and low) categories based on their observed and predicted susceptibility values, respectively. With the available data, the model showed a 40-50% success rate for classifying the streams based on three observed and predicted susceptibility categories. Model entropy also was calculated for selecting the best model. The results show the important role of both nutrients and other contributing factors in explaining the variation of algal biomass. The study also suggests ways to fine tune the model and improve its accuracy, which would make the presented model a more viable tool for stream classification for establishing nutrient criteria to prevent surface streams from eutrophication.     

Condition assessment of unshielded aged power and control cables byelectrical techniques

Experience with electrical diagnostic and high-potential tests, performed at the terminals of unshielded cables in older nuclear and thermal plants is presented. The three basic types of cable-low- and high-voltage power cables, control cables and instrumentation cables-that are important to the reliable operation of a generating station and large industrial plants are described, and their aging mechanisms are indicated. Dielectric testing of unshielded cables, the effect of grounding, field testing of station cables, and insulation characterization at low frequencies are discussed     

Fabrication and Characterization of Two‐Photon Polymerized Features in Colloidal Crystals

The fabrication and characterization of two‐photon polymerized features written within and outside of colloidal crystals is presented. Two‐photon polymerization (TPP) response diagrams are introduced and developed to map the polymerization and damage thresholds for features written via modulated beam rastering. The use of tris[4‐(7‐benzothiazol‐2‐yl‐9,9‐diethylfluoren‐2‐yl)phenyl]amine (AF‐350) as an initiator for TPP is demonstrated for the first time and TPP response diagrams illustrate the polymerization window. These diagrams also demonstrate that the polymerization behavior within and outside of colloidal crystals is similar and electron microscopy reveals nearly identical resolution. Fluorescence confocal microscopy further enables visualization of non‐self‐supporting, three‐dimensional TPP features within self‐assembled photonic crystals. Finally, microspot spectroscopy is collected from a two‐photon feature written within a colloidal crystal and this is compared with simulation.     

Work-oriented development of knowledge-based systems: a case for multiple perspectives

System development is strongly influenced by the perspectives used by system developers. Current development methods for knowledge-based systems are based on an information processing perspectives of experts and users which has been criticized by a number of researchers. The paper argues that work-oriented development of knowledge-based systems requires the parallel use of multiple perspectives (including the information processing perspective), and that the use of any single perspective is potentially dangerous. As an example of the importance of using multiple perspectives, thepaper presents the situated action perspective, and shows how it complements the information processing perspective.