NANTAWUT SRIARIYAWAT and ELENA MENEGUZ
Location: Stephenson Building, room F16 (first floor)
Time/Date: 13th May 2010, 16:00
Nantawut Sriariyawat:
"Impact of Lean production on supply chain sustainability"
The purpose of this study is to identify the impacts of Lean Production on the sustainability of supply chains, investigate similar or different impacts caused by Lean production between European and Eastern companies and develop new policy measures to support sustainable distribution in Thailand. There is inadequate quantitative data to assess the impact of Lean Production on supply chains, as opposed to manufacturing or distribution. There has been little research done in developing countries or Thailand. This research applied the Delphi technique for qualitative analysis using online data survey methods to address two panels, one a Thai expert panel and one a EU expert panel. This paper details major findings in the key areas of: partners relationships, location, scheduling, cost, information technology, warehouse, delivery transport, and environmental impacts. The preliminary results of Delphi survey showed how important of long term relationship between supplier and producer and a different perspective between eastern and western companies. Finding from Delphi study and case study will be utilised to develop new policy measures to support sustainable distribution in Thailand.
Elena Meneguz:
"On the exploitation of a Lagrangian methodology to quantify the segregation of inertial particles in turbulent flows: results and open questions"
This talk is concerned with the influence of turbulent structures on the growth, mixing and dispersion of liquid/solid particles. It is by now well known that turbulence (contrary to traditionally held views) can de-mix a group of particles initially uniformed distributed, segregating the individual particles into regions of high strain rate. Analytical studies have shown that the process can be highly intermittent with the occurrence of singularities in the particle concentration.
We consider particles with non-zero Stokes number in a turbulent gas governed by Stokes drag. We use a Lagrangian deformation tensor and its evolution equations. In this way we are able to measure the compressibility of the particle velocity field and the moments of the particle concentration, which show that below a certain threshold value the segregation goes on indefinitely with time (until particles collide) and that it is a highly intermittent process.
We tested this methodology in various “models” of flow field, beginning from rather simple two-dimensional one to more complex three dimensional kinetic simulations (KS) and direct numerical (DNS), and we observe only a quantitative difference in our statistics. A broader range of scales doesn’t seem to play an important role in our measurements: this is due to the fact that we are using a local parameter that depends only on the gradients of the flow. Can this be seen as a limitation? Which of the relevant features of turbulence are taken into account in our model and which are left out? State of the art and current open questions will be discussed during the presentation.
Published: 20th April 2010