Dynamics of urban and rural housing stocks in China

The massive migration flows from rural to urban areas in China, combined with an expected decline in the total population over the next decades, leads to two important challenges for China's housing: the growth of its urban housing stock and the shrinkage of rural housing. The rural and urban housing systems in China were analyzed using a dynamic material flow analysis model for the period 1900–2100 for several scenarios assuming different development paths for population, urbanization, housing demand per capita, and building lifetime. The simulation results indicate that new housing construction is likely to decline for several decades due to the fast growth over the past 30 years and the expected increased longevity of dwellings. Such an oscillation of new construction activity would have significant implications for the construction industry, employment, raw material demand, and greenhouse gas emissions to produce the construction materials. Policy and practical options for mitigating the negative impacts are considered.

Les flux migratoires massifs des zones rurales vers les zones urbaines en Chine, conjugués à un déclin prévu de la population totale au cours des prochaines décennies, entraînent deux défis importants pour le logement en Chine : la croissance de son parc de logements urbains et la diminution des logements ruraux. Les systèmes de logements ruraux et urbains en Chine ont été analysés en utilisant un modèle d'analyse dynamique des flux de matériaux sur la période 1900-2100 appliqué à plusieurs scénarios supposant différentes voies de développement concernant la population, l'urbanisation, la demande de logements par habitant et la durée de vie des bâtiments. Les résultats de la simulation indiquent qu'il est probable que la construction de logements neufs diminuera pendant plusieurs décennies en raison de la croissance rapide des 30 dernières années et de l'accroissement prévu de la durée de vie des logements. Une telle oscillation de l'activité de construction de logements neufs aurait d'importantes implications pour l'industrie du bâtiment, l'emploi, la demande en matières premières et les émissions de gaz à effet de serre résultant de la production des matériaux de construction. Les choix politiques et pratiques qui permettraient d'en atténuer les effets négatifs sont envisagés.

Mots clés: parcs de bâtiments, demande de constructions neuves, analyse dynamique des flux de matériaux, parc de logements, durée de vie, tendances, urbanisation, Chine     

Matisse: A System-on-Chip Design Methodology Emphasizing Dynamic Memory Management

MATISSE is a design environment intended for developing systems characterized by a tight interaction between control and data-flow behavior, intensive data storage and transfer, and stringent real-time requirements. Matisse bridges the gap from a system specification, using a concurrent object-oriented language, to an optimized embedded single-chip hardware/software implementation. Matisse supports stepwise exploration and refinement of dynamic memory management, memory architecture exploration, and gradual incorporation of timing constraints before going to traditional tools for hardware synthesis, software compilation, and inter-processor communication synthesis. With this approach, specifications of embedded systems can be written in a high-level programming language using data abstraction. Application of MATISSE on telecom protocol processing systems in the ATM area shows significant improvements in area usage and power consumption.     

Is bioethanol a sustainable energy source? An energy-, exergy-, and emergy-based thermodynamic system analysis

Biofuels are widely seen as substitutes for fossil fuels to offset the imminent decline of oil production and to mitigate the emergent increase in GHG emissions. This view is, however, based on too simple an analysis, focusing on only one piece in the whole mosaic of the complex biofuel techno-system, and such partial approaches may easily lead to ideological bias based on political preference. This study defines the whole biofuel techno-system at three scales, i.e., the foreground production (A), the background industrial network (B, including A), and the supporting Earth biosphere (C, including B). The thermodynamic concepts of energy, exergy and emergy measure various flows at these three scales, viz. primary resources, energy and materials products, and labor and services. Our approach resolves the confusion about scale and metric: direct energy demand and direct exergy demand apply at scale A; cumulative energy demand and cumulative exergy demand apply at scale B; and energy is applied at scale C, where it is named emergy, while exergy also can be applied at scale C. This last option was not examined in the present study.The environmental performance of the system was assessed using a number of sustainability indicators, including resource consumption, input renewability, physical benefit, and system efficiency, using ethanol from corn stover in the US as a technology case. Results were compared with available literature values for typical biofuel alternatives. We also investigated the influence of methodological choices on the outcomes, based on contribution analysis, as well as the sensitivity of the outcomes to emergy intensity. The results indicate that the techno-system is not only supported by commercial energy and materials products, but also substantially by solar radiation and the labor and services invested. The bioethanol techno-system contributes to the overall supply of energy/exergy resources, although in a less efficient way than the process by which the Earth system produces fossil fuels.Our results show that bioethanol cannot be simply regarded as a renewable energy resource. Furthermore, the method chosen for the thermodynamic analysis results in different outcomes in terms of ranking the contributions by various flows. Consequently, energy analysis, exergy analysis, and emergy analysis jointly provide comprehensive indications of the energy-related sustainability of the biofuel techno-system. This thermodynamic analysis can provide theoretical support for decision making on sustainability issues.     

The Institutional Arrangements of Innovation: Antecedents and Performance Effects of Trust in High-Tech Alliances

In this study we investigate the institutional arrangements of innovation processes in high-tech alliances, focusing on the role of trust. A major strength of the research is the opportunity to address antecedents as well as performance effects of trust. The antecedents of interorganizational trust include a shared past, detailed interfirm contracts, relational openness and mutual dependence. We control for the size and cooperative culture of the focal firm and the knowledge value of the partner firm. Data from a field study of 391 Dutch firms in high-tech industries generally support the research model. The results provide convincing evidence to support the value of interorganizational trust in durable business relationships that strive for the development of new technological knowledge.     

Microbial detection and monitoring in advanced life support systems like the international space station

Potentially pathogenic microbes and so-called technophiles may form a serious threat in advanced life support systems, such as the International Space Station (ISS). They not only pose a threat to the health of the crew, but also to the technical equipment and materials of the space station. The development of fast and easy to use molecular detection and quantification methods for application in manned spacecraft is therefore desirable and may also be valuable for applications on Earth. In this paper we present the preliminary results of the SAMPLE experiment in which we performed molecular microbial analysis on environmental samples of the ISS as part of an ESA-MAP project.     

Life cycle assessment of municipal solid waste management with regard to greenhouse gas emissions: Case study of Tianjin, China

The environmental impacts of municipal solid waste (MSW) management have been highlighted in China, due to the continually increasing amount of MSW being generated and the limited capacity of waste treatment facilities. Of particular interest is greenhouse gas (GHG) mitigation, aided by the Kyoto Mechanisms. China is an important case study for this global issue; however, an analysis of the entire life cycle of MSW management on GHG emissions is not available for China. This study evaluates the current and possible patterns of MSW management with regard to GHG emissions, using life cycle assessment (LCA), based on the Tianjin case. We assess the baseline scenario, reflecting the existing MSW management system, as well as a set of alternative scenarios, five exploring waste treatment technology innovations and one exploring integrated MSW management, to quantitatively predict potentials of GHG mitigation for Tianjin. Additionally, a sensitivity analysis is used to investigate the influence of landfill gas (LFG) collection efficiency, recycling rate and methodological choice, especially allocation, on the outcomes. The results show GHG emissions from Tianjin's MSW management system amount to 467.34 Mg CO₂ eq. per year, based on the treatment of MSW collected in the central districts in 2006, and the key issue is LFG released. The integrated MSW management scenario, combining different improvement options, shows the highest GHG mitigation potential. Given the limited financial support and the current waste management practice in Tianjin, LFG utilization scenario would be the preferred choice. The sensitivity analysis of recycling rate shows an approximately linear relation of inverse proportion between recycling rate and total GHG emissions. Kitchen waste composting makes a considerable contribution to total GHG emissions reduction. Allocation choices result in differences in total quantitative outcomes, but preference orders and contributions analysis are found to be robust, suggesting LCA can support decision making.     

Life cycle assessment of flax shives derived second generation ethanol fueled automobiles in Spain

Biofuel use seems to have certain environmental, energy and socioeconomic advantages versus fossil fuel consumption. The substitution of fossil fuels with biofuels can be a useful tool to fulfil the Spanish and European policy in relation to mitigation of greenhouse gas (GHG) emissions and increase the security in energy supply. The continuous increase in energy consumption, dependence on energy and high petroleum prices has motivated increasing support for renewable energy promotion. In Spain (the third ethanol producer in Europe in 2007), ethanol from lignocellulosic feedstocks could be one of the most valuable and interesting possibilities for renewable transportation fuels due to the limited competition with food production and high net reduction of GHG emissions. This study is focused on flax shives, obtained as an agricultural co-product from flax crops dedicated to fibre production for specialty paper pulp manufacture as lignocellulosic biomass to produce second generation ethanol involving the use of cellulosic technology. The life cycle assessment (LCA) methodology was used to evaluate the environmental impacts of the production and use in a flexi fuel vehicle (FFV) of ethanol blends (10 and 85% in volume of ethanol with gasoline) versus conventional gasoline, throughout their whole life cycle in order to highlight the main sources of these impacts. The system boundaries include cultivation, extraction, processing and final use of fuels. Mass and economic allocation were considered to determine the effect on the results of different allocation approaches.The results of the study show that the allocation methods are essential for outcomes and decision-making. Using ethanol as transportation fuel could present better environmental performance than conventional gasoline in terms of global warming and fossil fuel consumption according to mass allocation. However, environmental credits could be achieved in terms of acidification, fossil fuel consumption and human toxicity according to economic allocation. Contributions to other impact categories such as eutrophication and photochemical oxidants formation were lower for conventional gasoline regardless of the allocation procedure selected. Agricultural activities related to feedstock production are notable contributors to the environmental performance. Thus, high yielding varieties, reduction of tillage activities and reduction in fertilization should help to reduce these impacts.     

Integrated systems analysis of persistent polar pollutants in the water cycle.

Persistent polar pollutants (P3) are difficult to degrade in standard waste water treatment plants. As a result, they end up in the effluent and are emitted to the surface water. In some areas, this problem is aggravated through "closed loop recycling", causing concentrations of P3 in surface water to build up over time. This could cause violation of (future) EU regulations. In the P-THREE project, various alternative waste water treatment techniques are investigated regarding their effectiveness in eliminating these substances, especially membrane bioreactor treatment and advanced oxidation processes, MBR and AOP. The integrated systems analysis which is the subject of this paper assesses these techniques in a broader systems context: (1) the life-cycle of the P3, (2) the life cycle of the WWTPs, and (3) the WWTP life cycle costs.     

Microbial detection and monitoring in advanced life support systems like the International Space Station

Potentially pathogenic microbes and so-called technophiles may form a serious threat in advanced life support systems, such as the International Space Station (ISS). They not only pose a threat to the health of the crew, but also to the technical equipment and materials of the space station. The development of fast and easy to use molecular detection and quantification methods for application in manned spacecraft is therefore desirable and may also be valuable for applications on Earth. In this paper we present the preliminary results of the SAMPLE experiment in which we performed molecular microbial analysis on environmental samples of the ISS as part of an ESA-MAP project. This article is a reprint of Microgravity sci. technol. XVIII-3/4 (2006). Tab. 1 has been corrected.     

NETWORK INTERACTIONS AND MUTUAL DEPENDENCE: A TEST IN THE CAR INDUSTRY

By engaging in specific investments a firm may develop a unique competence value for its partner, which makes the partners mutually dependent. This may neutralize any hold-up risk of an opportunistic partner that is tempted to exploit the dependence and appropriate a greater share of the value added in the relation. The purpose of this paper is to investigate such mechanisms of mutual dependence. The analysis builds on previous theoretical and empirical research by the authors. It is based on an integration of transaction cost economics with the resource (competence, capabilities) view and a social exchange view, from a dynamic perspective. The paper asks the following: How do competencies develop in interaction between firms? The social exchange view brings in trust as an important dimension of governance. The research question asks how risks of mutual dependence between firms may be mitigated without either hierarchical or legal control. Five hypotheses concerning such mechanisms of mutual dependence are tested on data from the car industry.