IIE Seminar Series
January - June 2010
The Institute for
Infrastructure and Environment holds informal seminars on Monday lunchtimes (13.00-14.00) in the AGB
Seminar Room. The seminars are open
to all.
For further information, or to offer a seminar,
please contact - Prof. Yong Lu or Joan Birse
Speakers are encouraged to read the Guidance
Notes.
The details of past seminars are also available.
Abstracts
Dr Jian-Fei Chen
IIE
Finite Element Modelling of Reinforced Concrete Beams with Externally Bonded FRP Shear Reinforcements
Monday 11 Jan 2010
|
| Many
reinforced concrete (RC) beams may need to be strengthened to enhance
their shear capacity to avoid the brittle and catastrophic shear
failure. This may be achieved by the external bonding of
fibre-reinforced polymer (FRP) reinforcement. The FRP reinforcement can
be bonded around the entire section (complete wrapping), to the two
sides as well as the soffit of the beam (U-jacketing), and to the two
sides of the beam only (side bonding), in the forms of strips, plates
or sheets. A significant number of studies have been conducted on the
shear behaviour of such strengthened beams. However, most of these
studies have been experimentally based and only a very limited amount
of research is available on numerical modelling of such beams using the
finite element (FE) method. The lack of in-depth FE studies is chiefly
due to the challenging nature of modelling shear cracking in RC beams
and the interfaces between different materials. This talk discusses the
key issues and challenges involved in the FE modelling of RC beams
strengthened with externally bonded FRP shear reinforcements, and how
they can be tackled in an advanced FE model. A number of numerical
examples will be shown to validate the FE model. The effect of varying
the bond-slip modelling approach for steel-to-concrete and
FRP-to-concrete interfaces will then be investigated to illustrate
their significance and complex nature. |
Dr. Charles Knapp
Senior Lecturer, University of Strathclyde (Glasgow)
Antibiotics and antibiotic resistance in the environment
13:15 Monday 18 Jan 2010 |
Antibiotic
resistance genes are emerging contaminants of concern; these genes are
being found at elevated levels in sediments and other aquatic
compartments in areas of intensive agricultural, urban, and industrial
activity. However, until recently, most monitoring data has been
non-quantitative, which although useful, does not provide the
information needed to develop predictive remediation strategies. To
address this data gap, we have performed an array of laboratory,
mesocosm, and field scale studies aimed at quantifying the migration,
attenuation, and fate of specific resistance genes in different aquatic
and sediment settings. These studies have combined detailed water
chemistry in exposed systems with the development and application of
numerous quantitative PCR tools for tracking genes in environmental
samples. This presentation will summarize results of many studies, but
will focus on environmental factors that tend to reduce resistance gene
levels after release to the environment.
Short bio:
Dr Charles Knapp is a Senior Lecturer at University of Strathclyde
(Glasgow); his research interest involves the integration of
state-of-the-art microbiological measurement technologies and
ecological principles into the realm of environmental protection and
sustainability. His research experience includes various themes
including nutrient and population dynamics, water quality, and
eco-toxicology.
|
Robert De Bold
PhD student, IIE
Using Frequency Response Function Testing to Examine a Railway Trackbed |
The
increase in both freight and passenger rail travel has driven the
demand for more efficient and rapid investigation of railway trackbed
ballast.
One of the current approaches to evaluating the stiffness of railway
ballast is to use a Falling Weight Deflectometer. Whilst this is very
effective, it requires the rails to be unclipped from the ties –
thus, it is very intrusive and expensive.
This paper explores the option of using a frequency response function
(FRF) generated by using a 12lb instrumented hammer to excite the
railway trackbed. Finally, the FRF is correlated with the ballast
fouling. |
Dr Imma Oliveras
School of Geography and the Environment, University of Oxford
Fire Dynamics and Associated Carbon Losses in the Peruvian Andes |
| In
the Andes, humid Tropical Montane Cloud Forests (TMCFs) sit immediately
below highly flammable, high altitude dry grasslands (the puna) that
have suffered from recurrent anthropogenic fires for millennia, with
the treeline sitting at approximately 3000 m. This treeline is a zone
of ecological and climatic tension: on the one hand, rising
temperatures and cloud heights may have a tendency to push the ecotone
upwards, encouraging forest expansion into the puna. On the other hand,
increased aridity in the puna (driven by rising temperates and
evapotranspiration, and possibly by reducing precipitation), coupled
with intensified human pressure, is increasing fire occurrence and
penetration into the cloud forest. This research project aims analyze
the fire dynamics of this treeline, and to perform accurate estimates
to carbon losses due to combustion by combining fire satellite
detection, on-ground observations and experimental tests. |
Professor TorOve Leiknes
Alternative membrane processes for removal of NOM in drinking water treatment |
| The
aim of this presentation is to give an overview of current
state-of-the-art drinking water treatment solutions based on membrane
technology, highlight recent developments and research trends, and to
assess these with respect to their capacity and efficiency for the
removal of NOM in raw water sources. |
Paolo Fiorucci
CIMA, Univ. of Genoa, Italy
A general framework for wildfire risk assessment and management in Mediterranean area |
The
analysis of time series of burned areas combined with a detailed
knowledge of topography, land cover and climate conditions allow
understanding which are the main features involved in forest fire
occurrences and their behaviour. Based on this information it is
possible to develop statistical methods for the objective
classification of forest fire static risk at regional scale. The
analysis suggests that fire regime in Mediterranean ecosystem is
strictly related with species highly vulnerable to fire but highly
resilient, as characterized by a significant regenerative capacity
after the fire spreading. Only rarely, and characterized by negligible
damage, the fire affects the areas covered by climax species in
relation with altitude and soil types (i.e, quercus, fagus, abies). On
the basis of these results, it is proved how the simple Drossel-Schwabl
Forest Fire Model is able to reproduce the forest fire regime in terms
of number of fires and burned area.
On this basis, an experimental propagation model has been developed to
provide Italian Civil Protection Department (DPC) with rapid active
fire risk assessment maps......
BIOG
Paolo Fiorucci has a PhD in Environmental Monitoring. He is currently
project leader at CIMA. CIMA is a Joint-Foundation between the
University of Genoa and the Italian Civil Protection. It supports
research in the field of civilian and environmental protection. His
research interests focus on forest fire risk assessment and management
by means of statistical analysis and dynamic model development. He is
author and co-author of more then 30 papers, 7 published in
international refereed journals. He is also teaching assistant from
1997 supporting different courses on Modelling and Simulation, Natural
risk management and Forest Fires within the undergraduate courses on
Environmental Engineering and Electronic Engineering at the University
of Genoa. He has been and he his Scientific Director of several
national and international projects.
|
Prof. Rama Bhargava
Indian Institute of Technology
Can we sustain without computational techniques? |
| This
talk will emphasize the importance of computational techniques with
special reference to CFD (computational fluid dynamics) and heat
transfer. Designing advanced engineering systems requires use of CAD
tools which rely heavily on finite difference and finite element
techniques. Some typical applications are aerodynamics of vehicles,
heat transfer analysis in engine pistons etc. In spite of a lot of
commercial software, FEM still has a few important limitations. A
description of FEM, “its goals and holes”, will be a part
of the talk along with how this technique developed mathematically. A
brief description of some of the meshfree techniques and their need
will also be explained. |
Prof. Kevin Lyons
North Carolina State University
Studies of Turbulent Reacting Flows: Experiments |
Studies
are presented that examine a variety of phenomena in jet flames,
including current work in flame propagation, hysteresis and
blowout. At a certain jet exit velocity, a flame will lift from
the fuel nozzle and stabilize at some downstream position. The
partially-premixed flame front of the lifted flame oscillates in the
axial direction, with the oscillations becoming greater in flames
stabilized further downstream. These oscillations are also
observed in flames where blowout is imminent. This work attempts
to determine the role of fuel velocity and air co-flow on flame
oscillations in both stable and unstable regimes. The results of
video imaging of a lifted methane-air diffusion flame are
presented. Images are used to ascertain the changes in the
reaction zone that influence these oscillations and relate the movement
to blowout. Similar studies are presented in studies of upstream
flame propagation in jets flames. If time allows, other work in
flame hysteresis, flame hazards in explosions and firefighting
situations and the like, will be discussed.
Brief Bio:
Lyons received his Ph.D in Mechanical Engineering in 1994 from Yale
University where he studies optical diagnostic techniques in reacting
flows. Since 1994, he has been on the faculty of North Carolina
State University in Raleigh, where he is Professor of Mechanical and
Aerospace Engineering. His research interests are in the areas of
hydrocarbon flame structure, stabilization and propagation
(ignition/extinction), spray flames, flame threats from
explosions/flash fires and combustion control. Over his career,
he has collaborated with researchers at Wright Patterson Air Force
Base, Navy in China Lake, Sandia National Laboratories and IBM, among
other institutions, and has delivered lectures recently at the von
Karman Institute in Brussels and at INSA-Rouen in Turbulent
Combustion. Most recently, he is becoming interested in skin
burns and protective gear assessment for protecting firefighters and
other first responders.
|
Prof. Harald Horn
TU München, Garching, Germany
Biofilms – microorganisms organized in an interplay between growth,
detachment and mass transport |
In
a study on biofilm development and detachment a heterotrophic biofilm
derived from activated sludge was cultivated in a continuous once
flow-through tube reactor. The system was exposed to constant
substrate and laminar flow conditions. Confocal laser scanning
microscopy (CLSM) and chemical analysis was used to study the impact of
detachment and sloughing on the remaining but further developing
biofilm structure. An unexpected succession from a compact to a
filamentous biofilm surface structure was observed directly after heavy
sloughing events. This was surprising as both hydrodynamic and
substrate conditions were not changed and no specific re-inoculation
was applied.
It is speculated that the development of filamentous microorganisms may
have two reasons: Firstly, filamentous microorganisms which may have
been dormant at the base biofilm adapted quicker to the conditions
after sloughing. Secondly, other bacteria attached after sloughing to
the remaining base biofilm quickly adapted and grew into a filamentous
biofilm.
Although CLSM images showed a completely different biofilm structure
before and after sloughing the overall biofilm performance in terms of
substrate conversion rates remained constant. A one dimensional
model approach revealed that key parameters for mass transfer and
diffusion have to be changed by half an order of magnitude after the
start of filamentous growth to match the experimental results.
The combination of experimental and simulation results are significant
for applied aspects of biofilm growth and detachment under real world
situations as demonstrated in this laboratory once flow through
system. A further consequence of the changing biofilm structure
was a change in
physicochemical processes (i.e. substrate transport). The adapted
model can only be applied as diagnostic tool. Nevertheless, it
helps to understand the interaction of hydrodynamics, structures and
processes in microbial biofilms. So far, such an unsteady
behaviour of cannot be simulated with a generalized biofilm model.
|
Prof Puneet Mahajan
Dept. of Applied Mechanics
Indian Institute of Technology( Delhi)
Mechanical Behavior of Multidirectional Carbon-Carbon composites |
Carbon–carbon
(c/c) composites have low density, high stiffness and retain their
properties at high temperature. Commonly used architectures for these
composites are 3-directionalorthogonal, 3-directional 8 harness satin
weave and 4-directional in plane. In the first part 3-Dimensional unit
cells are established for different architectures and asymptotic
homogenization along with periodic boundary conditions was used to
determine the equivalent homogeneous mechanical properties
corresponding to these unit cells. Finite Element Method (FEM) was used
to compute the volume averaged stresses and strains required for
calculating homogenized properties. The interfaces between the fibre
bundles and matrix were modelled using cohesive elements to account for
effect of debonding on the composite properties. These properties were
compared with the experimental results.
Continuing with this work, in the second part a computed tomography
tomography (CT) scan is performed on a composite specimen and 3D image
is reconstructed. Unit cells are taken from different regions in the
reconstructed image and analyzed using FEM. The manufactured composite
has significant internal damage like, voids, matrix cracking and
debonding at interfaces due to the mismatch in thermal stresses induced
during manufacturing process. All these imperfections, that influence
the mechanical properties of the composite, are included in the FE
mesh. Each unit cell was analysed using the same method as in the first
part. The unit cells from different regions show up to 10% variation in
the properties.
To determine the variation of properties with strain, properties of the
interface (strength, fracture energy and coefficient of friction) are
needed. Push out and pull out tests have been performed to
determine these interfacial properties. Attempts are on to incorporate
these in the unit cell model.
|
Professor Deric Oehlers
Adelaide University
Our obsession with curvature in reinforced concrete |
Much of the early research on steel reinforced concrete
dealt with steel reinforcement that was both ductile and had a very
strong bond with the concrete. Hence partial-interaction, that is slip
between the reinforcement and concrete and subsequently debonding, has
not been a major issue. This has allowed researchers to develop the
two-dimensional full-interaction moment-curvature approach to model the
three-dimensional behaviour of reinforced concrete. It is shown that
this wholly two-dimensional full-interaction moment-curvature approach
relies on a very large amount of empirical calibration to ensure a safe
design. Furthermore, being empirical and, therefore, only applicable
within the range of tests from which they were calibrated, it is of
little use in developing new products or for new applications such as
blast and seismic loads. It is this obsession with curvature that has
held back the development of reinforced concrete.
A new structural mechanics moment-curvature approach combined with
discrete rotation (the latter was first recognized by Bachmann way back
in 1970) is described. It is shown that this new approach can be used
to develop structural mechanics models to replace the empirical models
from the wholly moment-curvature approach such as empirical hinge
lengths for rotation, empirical effective flexural rigidities for
deflection and empirical equations for crack spacings and widths. It is
suggested that these new structural mechanics models will allow a more
rapid development of new products such as FRP confined concrete and new
applications such as for extreme loads. It is suggested that it is time
to overcome our obsession with curvature.
*_About the Speaker_*
Deric Oehlers is Professor of Structural Engineering at the School of
Civil, Environmental and Mining Engineering at The University of
Adelaide, Australia. He holds a Bachelor degree in Civil Engineering
from London University and a Masters and PhD from Warwick University,
UK, and was awarded a Doctor of Engineering from Adelaide University,
Australia, for his research into the partial-interaction behaviour of
both composite steel and concrete structures and FRP reinforced and
retrofitted concrete structures. He has published 120 journal papers
and 4 books which include the Australian retrofitting guideline
“Design Guideline for RC structures retrofitted with FRP and
metal plates - Standards Australia HB 305” which was published in
2008. |
Prof. H S Mukunda
ABETS, CGPL, Indian Institute of Science (IISc)
Centre for Disaster Mitigation (CDM), Jain University (JU)
Bangalore, India
Combustion and Gasification research and technology development at IISc and Fire research at JU |
Principal contributions in combustion and gasification
research, technology development and field outreach performed over the
last four decades at IISc are briefly summarized. Two significant ones
are brought out.
a. Using a unsteady one-dimensional code (with complex chemistry) for
flame propagation developed at the laboratory over five years, it was
conclusively demonstrated that the flammability limits of gaseous
fuel-oxidant mixtures /cannot be explained with adiabatic propagation/,
a subject on which considerable debate existed in the literature for a
long time. Very small heat loss is adequate to replicate experimental
data on the limits. Strretch (or strain) effects on premixed flames
demonstrate sensitivity to detailed chemistry ignored in the literature.
b. Computation of diffusive combustion of two-dimensional sandwich
propellant combustion (polymer-AP sandwich) with /condensed phase
unsteadiness/ ignored till this work was done shows that for steady
combustion to occur, the parameters of oxidizer pyrolysis have to be
lower than from traditionally chosen values from low heating rate
studies.
Biomass gasification research and technology development has led to the
evolution of a reactor design with staged air injection with the
ability to control the peak temperature and reduce the tar generation
to enable handle a variety of solid bio-fuels (agricultural residues).
Gas cooling and cleaning systems with reduced load of tar (that is
treated in the hot section of the reactor naturally) also have novelty
– a low temperature water spray condenses on the particulate
matter and drops it off from the gas phase. A powder coated filter
provides final clean up to ppb levels of dust and tar. This frontier
work has created partnership with engine manufacturers – Cummins,
India and Jenbacher (Austria) for producer gas based power generation.
The links between the combustion research outlined earlier and producer
gas combustion in engines are briefly brought out. Partnerships,
technology transfers on gasification and power generation, and
activated carbon production are also outlined. An off-shoot of this
research into fan based modern gasifier based cook-stoves for domestic
and semi-industrial applications with product development, tech
transfer and field outreach to a half-million households is described.
At the CDM, JU work has begun in collaboration with Underwriter
Laboratories (UL) to set up a testing facility for client applications.
In parallel, a research group for conducting investigative experiments
and modeling the fire dynamics using FDS is currently being set up. The
primary aim of this effort is to create a predictive tool for
describing toxic compounds in building related fires and assist the
architects and users in understanding the relationship between fire
load and fire dynamics. |
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