Numerical modelling of the time dependent behaviour of clays

In the last two decades extensive research has been undertaken to characterize the time and rate dependent response of soils and to describe it by means of a constitutive model. However, most of these constitutive equations have been dev.eloped for a single stress point and limited stress paths, and in engineering practice the time, dependent nature of soils is still commonly reduced to a single coefficient of secondary consolidation obtained from a 24h oedometer test. J This thesis describes the development and implementation, in the Imperial College Finite Element Program (I~FEP), of two elastic visco-plastic models based on the overstress theory to describe the stress-strain-time/rate behaviour of clayey soils. The models differ essentially in the adopted law to describe the variation of the creep ~ deformation with time. The fIrst model - Creep Model 1 - incorporates a linear logarithmic law to describe the variation ofthe creep defon:nation with time, while the second model- Equivalent Time (ET) Model - incorporates a non-linear logarithmic creep law, with a limit to the amount of volumetric creep strain that can occur. The implementation and performance of the models is validated through a series of simple fInite element analyses that mimic common l~boratory stress paths and show that the models are able to reproduce the' phenomena of primary and secondary compression, stress relaxation, primary and secondary creep and persistent rate effects on the stress-strain .response under Ko and triaxial stress conditions. The ET model is then used to investigate the increase in bearing capacity of preloaded footings on soft clay, taking into account both the effects of consolidation and soil hardening due to creep with time. Finally, a series of fInite element analyses are presented that mimic the loading tests performed on two instrumented rigid footings at the Bothkennar test site. These analyses highlight the importance of considering the soil viscous effects in engineering practice and the need to account for the soil creep non-linearity if good predictions of the long-term settlements of geotechnical structures are to be made.Imperial Users onl

Standards compliance as an alternative learning opportunity under globalization in Latin America

globalization, technological infrastructures, certification, capability, Latin America, Chile

The motivations, organisation and outcomes of university-industry interaction in the Netherlands

This paper aims at analysing the impact of institutional and organizational factors on bridging industrial and university motivations for collaboration, as well as on the content, management and outcome of this relationship, in the Netherlands. In particular, we explore which type of projects, set up under specific industrial and university motivations, are more likely to face institutional barriers related to technology, market and organisational incentives frameworks. Moreover, we analyse the impact of technology transfer offices, research sponsoring, part-time professorships, and patenting on aligning university and industry motivations towards collaboration. To proceed empirically, thirty in-depth cases of successful university-industry knowledge transfer are analysed.university-industry interaction, innovation cooperation

Traditional versus Heterodox Motives for Academic Patenting: Evidence from the Netherlands

International audienceThis paper examines what motivates university researchers to patent the results of collaborative research with business firms. We provide evidence of the existence of a motivational academic patenting space comprised of: i) an industry-driven domain related to traditional-market motives (protection of inventions that will be commercialized); ii) a university-driven domain driven by various ('heterodox') motives related mostly to signalling specific research competences; iii) a 'hybrid' publicly-driven domain related to projects aligned to the research agendas of public sponsors. These three types of motivations reflect the connections between academic patenting and different types of innovation, and the roles of industry partners in proposing, financing and performing specific research projects. We use data from 16 in depth case studies of innovations developed by Dutch universities to provide preliminary empirical evidence of this typology of motivational spaces for patenting university knowledge

The performance of university-industry collaborations : empirical evidence from the Netherlands

no abstrac

Formal and informal external linkages and firms' innovative strategies: A cross-country comparison

Firms increasingly rely upon external actors for their innovation process. Interaction with these actors may occur formally (i.e. through a collaboration agreement) or informally (i.e. external actors acts as sources of knowledge). This paper analyses the reasons why firms consider it to be important to develop formal and informal external linkages in the innovation process by looking at the role played by firms’ innovative strategies and by taking into account that a complementarity or substitutive relationship might exist between formal and informal linkages. Data come from the Third Community Innovation Survey (CIS 3), where we have access to firm level micro-data from Norway, Sweden, the Netherlands and the UK.External knowledge sources, Innovation strategy, Formal cooperation, Multinomial Probit.

Imprints from idea origin on innovation and the development environment

This study builds on the evolutionary and organization literatures to explore how the nature of innovation outcomes was influenced by the innovation’s original idea and the environment in which it was developed. We use data from a survey of inventors on the development processes of three types of innovations: market success innovations, technologically novel innovations, and innovations that are both technologically novel and of market success. Our results suggest that the environment in which the project is developed erodes the effect of the original knowledge sources on the innovation outcome. Specifically, a stronger imprinting effect of knowledge sources is found for independent inventors, while ideas are more likely to be eroded in projects undertaken by inventors at technology leader firms

Formal and informal external linkages and firms' innovative strategies. A cross-country comparison

Firms increasingly rely upon external actors for their innovation process. Interaction with these actors may occur formally (i.e. through a collaboration agreement) or informally (i.e. external actors acts as sources of knowledge). This paper analyses the reasons why firms consider it to be important to develop formal and informal external linkages in the innovation process by looking at the role played by firms' innovative strategies and by taking into account that a complementarity or substitutive relationship might exist between formal and informal linkages. Data come from the Third Community Innovation Survey (CIS 3), where we have access to firm level micro-data from Norway, Sweden, the Netherlands and the UK.External knowledge sources, Innovation strategy, Formal cooperation, Multinomial Probit

Collaboration objectives and the location of the university partner: evidence from the Piedmont region in Italy

This study examines firms' decisions to collaborate with universities in their region as opposed to non-regional universities, focusing on the role of collaboration objectives. Through a survey of a representative sample of manufacturing firms in the Piedmont region (Italy), we find that firms seeking business advice are more likely to collaborate with regional universities while firms seeking R&D support and testing and analysis services are more likely to collaborate with both regional and non-regional universities. The partner university's location is endogenous to the level of investment in the collaboration; and the collaboration objectives provide good instruments. Some implications for regional policy are discussed

Performance of university-industry collaborations, qualitative and quantitative evidence from the Netherlands

This paper aims at identifying the elements that positively affect the performance of university-industry collaborative projects. We look in particular at the level of scientific and technological achievements of the project, the degree to which firms make use of the knowledge developed, and the subjective evaluation of both involved parties. Moreover, this paper examines the factors affecting the different perceptions of barriers to university-industry collaboration. To undertake this research, we rely on both in-depth data collected on 30 cases of university-industry collaboration to the development of a specific knowledge and/or technology, as well as on Dutch survey data collected via two questionnaires - one addressing industrial researchers and the other academic researchers. Our results suggest that project’s performance depends on the type of knowledge being developed, on the origin of the projects’ idea, and on the level and type of university-industry interaction during the project. We find that university-driven projects, although being more risky and troublesome, allow obtaining unexpected fruitful scientific and technological developments, with high spillovers to several other fields. Industry-driven projects, in turn, are more likely to benefit participating firms. Absorption of knowledge developed in collaborative projects depends on factors residing mainly on the industrial side. Firms need to invest in capability building and in knowledge transfer, especially in labour mobility. For both industry and university, earlier experiences have a positive effect on the evaluation of their collaboration. They also avoid overemphasising barriers to collaboration. Still, when both parties join the project with different expectations, they are likely to evaluate differently their project. This is also the case when projects results are of different value for the respective parties