Compress it

Stretch it

Bend it

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International Collaborative

Research Program

University of Glasgow, UK

University of Ballarat, Australia

University of Alberta, Canada

University of Bolton, UK

University of Victoria, BC, Canada

Bursa Technical University

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Teaching

Engaged students • Active Learning

Teaching Philosophy (Tools)

• Feed back

o From Students

o To Students

• BOPPPS based lesson plans

o Bridge in

o Objectives

o Pre assessment

o Participation

o Post assessment

o Summary.

Professional Competencies

Professional Development Program in University Teaching at Learning and

Teaching Centre of University of Victoria, BC, Canada, which is a dynamic program

focused on the development of pedagogical knowledge and practical skills

applied to teaching in Post Secondary education.

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Volunteer for: Let’s talk Science, UVic, Victoria, BC, Canada Learning and Teaching Centre, UVic, Victoria, BC, Canada International Council for Industrial and Applied Mathematics (July18–22, 2011),

Vancouver, BC, Canada.

Westcoast Women in Engineering, Science & Technology, Canada International Association of Engineers (IAENG) Canadian Smart Material and Structures Group (CANSMART) Professional Development Program in University Teaching (PD-PUT) Association for Women in Mathematics (AWM) Canadian Mathematical Society

COMMUNITY INVOLVMENT

MEMBERSHIPS AND PROFESSIONAL DEVELOPMENT

Applied Mathematical Modelling Journal of Engineering and Technology Research International Journal of Materials Engineering and Technology Mechanics of Advanced Materials and Structures Mechanics of composite materials World Academy of Science, Engineering and Technology

Journal Paper Reviewer

Professional Competencies

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Current Research activities …..

Research

Areas of strength

• Metal and polymeric stents and • Microfibrous scaffolds, • Implants and prostheses • Nano - fiberous drug delivery systems

Wave Propagation, thermal spreading resistance, dynamic soil structure interaction, Magnetothermoelasticity.

Smart materials and applications – Auxetic materials , Biomechnaics of tissues, Electrospinning, Micromachining, Thermoelasticity, Applied Mathematics, Elasticity , Non- linear elasticity.

Other areas of interest

Modeling, designing and fabrication of

Professional Competencies

Improving performances of structures with smart auxetic pattern 7

Overview

1. Introduction to Current Research Activities

2. Motivation and Objectives

4. Auxetic Materials

Introduction

Mechanical Properties

Potential Applications

6. Publications

5. Summary

3. Approach

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More than one million stents are implanted each year in the world. Around 60% stenting procedures are carried out annually in US only and 600,000 for the heart patients .

Stents have emerged as effective treatments to keep open the passageways which are obstructed by a variety of diseases

Arteries blocked with plaque

Esophagus damaged with esophageal cancer

Airways blocked due to lung cancer

Scar inflammation or weakening of the airway wall

Introduction Introduction to Stents

Background..

Concept of remodeling the artery was introduced in 1964

to open the blockage due to the formation of plaques and fatty materials

Entery into mainstream in 1977

through a procedure called angioplasty to restore blood flow However,

Angioplasty has shortcomings

The opening created by this procedure is not very smooth 9

Moreover,

recoiling causes the channel to become smaller shortly after being enlarged by balloon expansion.

Because..

the balloon does not evenly expand all areas,

Within the expanded channel a gradual build-up of material starts which in 30-60% of cases cause the blockage to return to its original or worse severity known as restenosis.

Thus…

The concept of the stent arose as a means

to mitigate elastic recoil of the artery,

control restenosis and to strengthen the artery wall.

They do not require an open heart surgery as they are implanted directly through the arteries 10

A brief introduction stents implantation …

Initially having a small diameter in their crimped form stays over a balloon catheter and track to diseased or blocked area.

On inflation of balloon the stent expands to desired diameter,

get grip with artery walls and forms a scaffold.

Therefore,

Elastic and mechanical behavior of stents need to be match with native tissue.

To date a variety of stents (over 40) are commercially available or in development made of

Stainless steel, Nitinol shape-memory alloy, platinum, tantalum, or gold, polymer, metallic, plastics

Coated, un-coated, balloon-expandable, self-expandable

Drug-eluting stents emit medicines that help prevent artery reclosure.

Hence, the development of stents is a significant milestone in the treatment of blockage. 11

Although…

their success has been outstanding, but the patients that have received stents are at risk to: thrombosis restenosis stent migration inflexibility mismatches in mechanical behavior between stented and non-stented vessel areas

Due to restenosis within the first year approximately 15-30 percent of stented arteries re-block and patients are treated again with repeat surgery.

Further…

Drug-eluting stents have been shown to reduce the restenosis rate by 80 percent and also minimize other early and delayed complications A new era for stent technology ….

Started at beginning of 2011 with world’s first drug-eluting bioresorbable stents.

There is a room to develop new technology in stent fabrication to improve the quality of lives of patients

But still…

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Though ….

Therefore , major current challenge is ….. To develop, design and manufacture such stents that are:

• maximally compatible with living tissue

• the elastic response of a biomaterial should be matched with o the biological function and o mechanical properties of native tissue

• minimise major threats of stenting such as o thrombosis, restenosis and other early and delayed complications

Longitudinal Compression / Extension

Radial Compression Flexion

Torsion

• Compatible to physiologically relevant strain conditions

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Studies and experiments have demonstrated….

Auxetic materials

Offer a huge potential in biomedical industry

Auxetic stents can minimise the negative effects of current stent designs through:

• tailored enhanced mechanical properties

• tuned geometrical structure

• deformation mechnism

The development of novel auxetic stents is achieved through multidisciplinary

approach using micro/nano technlogy to tailor auxetic design and unique

deformation mechanism.

To design and fabrication of

• auxetic stents carrying nanofibrous drug delivery system and

• characterization of their mechanical properties.

Therefore, auxetic stent will be beneficial to improve early and delayed

complications of stenting hence quality of life of patients.

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Therefore, the main focus of my current research is……

Approach Combination micro/nano techniques

Micromachining

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Laser Welding

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Electrospinning

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Auxetic PCL (Polycaprolactone) micromacined microfibrous stent

Auxetic micromacinedmetal stent with nanofibrous drug delivery system for

Esophegus cancer

Novelty achieved …..

Better flexibility , expandable diameter without shortening the original length, good grip which will help to control in-stent-restenosis .

Multidisciplinary approach , Unique deformation mechanism achieved through auxetic structure and tailored mechanical properties.

Through….

What are Auxetic Materials ?

. …Fung, Y.C., Foundations of Solid Mechanics,

Prentice-Hall, pg.353, 1968. …….Love, A.E. H., “Treatise on the Mathematical Theory

of Elasticity”, pg. 163, 1927.. a cubic single crystal pyrite

This behaviour doesn’t contradict

theory of elasticity…

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What gives rise to auxiticity…..

The material’s geometrical

structure

The way the internal structure

deforms when loaded

Mechanism and structure

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Stainless Steel 316 sample

Before stretching After stretching

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Polyurathylene Foam Sample

Conventional Cylindrical Foam Auxetic Cylindrical Foam

http://www.youtube.com/watch?v=PLDbSWSm5i8&NR=1&feature=endscreen

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When ends are pulled, the disks tilt up,

increasing the material’s bulk.

PTFE expands because of its disk-

shaped particles connected with

strands

Nodule–fibril microstructure of auxetic PTFE

In the compressed state, the particles

lie flat and closely packed

Microstructure of polymeric materials

Polytetrafluoroethylene – PTFE

Accepted consequence of classical elasticity theory – A. E. H. Love(1927) in a cubic single

crystal pyrite.

The next documented evidence – Gibson (1982) in silicon rubber and aluminium honeycomb.

The intentional development – Roderick Lakes (1987) with fabrication of Polyuratylene Foam

History of auxetic material

This terminology was coined – Evans et al. (1991) with the fabrication of the microporous

polyethylene with negative Poisson’s ratio.

Since then, a wide range of materials have been produced covering the major classes of

materials -polymers, composites, metals, and ceramics.

The most recent exciting research concentrating on

Auxetic nanostructures

Liquid crystalline polymer

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Natural auxetic materials do exist.

Some biological materials have been found to be auxetic in certain forms of skin-

Arterial endothelium tissue

Single crystals of arsenic and cadmium

To name a few-

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Cat skin, cow teat skin, salamander skin

Cancellous bone from human shins

Several types of rocks

Cubic elemental metals and

α-cristobalite, iron pyrites

Auxetic materials are harder to indent…

Synclastic behaviour…

Saddle shape Conventional

materials upon bending

Dome shaped surface of

auxetic materials

Mechanical properties of auxetic materials

Other Properties: Enhanced shear resistance

Enhanced fracture toughness

More crack resistance

Anchoring potetials

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Implants and Prosthes - Artificial intervertebral disks, annuloplasty prostheses, knee

prosthetics and artificial blood vessels.

Potential Applications in biomedical …

For Example: In response to a

pulse of blood flowing through a

blood vessel (a) decrease in wall

thickness , (b) an auxetic arterial

material will become thicker.

Applicable for drug delivery systems and

wound dressings.

• allow the same range of motion that

the natural intervertebral disc allows

• prevent interference with

surrounding nerves

large (expandable)

diameter due to

deformation mechanism

Get a good grip with tumour tissue by

embedding inside the tissue

compared to conventional stent

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Applications in Aerospace

Curved body parts, aircraft nose-cones, wing panel

Protection

Blast protection curtains, crash helmet, projectile-resistant or bullet proof vest

Auxetics are used to make lightweight

wheels and runflat tires

An auxetic seat belt, however, would get wider this would spread the loads over a much larger area, potentially reducing any injuries experienced.

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Sensors and actuators

Hydrophone, piezoelectric devices, miniaturized sensors

Summary

Auxetic materials have a lot of potential applications from

biomedical to automotive and defense industries

Research involving auxetic materials and applications is

• highly interdisciplinary

• increasingly recognized as an integral component of smart materials

and is one of the 16 smart materials of 21st Century

• significant impact in the biomedical, aerospace and defence

industries and many other fields in a country and globally.

The tailoring of the Poisson’s ratio with improved mechanical

properties opens the door to new applications.

In addition, more research work needs to be done for further

understanding of these materials. Also, for future work it is necessary

to collaborate with researchers from textile, materials, chemical &

biological areas to explore the potential applications.

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History of Research in Auxetic Material

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1. S.K. Bhullar, Farid Ahmed, Junghyuk Ko, Martin Jun, Design and Fabrication of Stent with Negative Poisson's Ratio, International Journal of Mechanical, Industrial Science and Engineering, ISSN :2231-6477 , 8(2), 2014, 1-7.

2. Junghyuk Ko, Sukhwinder Bhullar, Nima Khadem Mohtaram, Stephanie M. Willerth, and Martin B.G. Jun, Controlling Topographical Properties of Poly (ε-caprolactone) Melt Electrospun Scaffolds through Mathematical Modeling, Journal of micromachning and microengineering 2013. (accepted).

3. S.K. Bhullar, Farid Ahmed, Martin Jun, Mechanical Characterization of an Auxetic Polymer Stent, Mechanics of Materials, 2014(in Process).

4. Sukhwinder K. Bhullar, Junghyuk Ko, Yonghyun Cho, Martin B.G. Jun, Fabrication and Characterisation of non-wovenAuxetic Polymer stent, Journal of Biomaterials Science: Polymer Edition, 2014 (in Process)

5. Sukhwinder K. Bhullar, Ayse Bedeloglu , Martin B.G. Jun, Auxetic Effect and Characterization of Polytetrafluoroethylene (PTFE) Tubular Structure, Journal of Biomaterials Applications, 2014(to be submitted soon).

6. S.K. Bhullar, A.T. Mawanane Hewage, A. Alderson, K. Alderson, Martin B.G. Jun, Influence of negative Poisson's ratio on stent fabrication and applications, Advances in Materials, 2013; 2(3): 42-47.

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Journal Papers (International Published)

7. S.K. Bhullar, J.L. Wegner1and A. Mioduchowski, Auxetic Behavior of Flat and Curved Indenters into a Half-Space, Journal of Materials Science and Engineering A 2 (5), pp. 436-441, 2012.

8. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, Auxetic Plate with a Crack under Shear Loading Journal of Materials Science and Engineering, USA, B 1, pp. 565-574, October 2011.

9. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, On Auxetic Versus Non-auxetic Indentation by a Rigid Conical Cylinder, Journal of Materials Science and Engineering, USA, Vol. 5, pp. 593-598, May, 2011.

10. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, Strain Energy Distribution in an Auxetic Plate with a Crack, Journal of Engineering and Technology Research Vol. 2(7), pp. 118-126, July 2010.

11. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, Auxetic behavior of a thermoelastic layered plate, Journal of Engineering and Technology Research, Vol. 2(9), pp. 161-167, September 2010.

12. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, Spherical indentation of an auxetic versus non-auxetic layered half –space, World journal of Engineering, September 2010, P567.

13. S.K. Bhullar, J. L. Wegner and A. Mioduchowski, Indentation of an Auxetic Half-Space by a Rigid Flat Cylinder, International Journal of Materials Engineering and Technology, volume 4 Issue 2, pp 101-117, 2010.ISSN no.0975-0444

14. S.K. Bhullar and J. L. Wegner, Thermal Stresses in a plate with an hyperelliptical hole, Journal of Engineering and Technology Research, Vol.1 (8), pp. 152-170, November, 2009.

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15. S.K. Bhullar and J. L. Wegner, Magnetothermoelastic Problem Of A Half-Space, IAENG International Journal of Applied Mathematics, Volume 39, Issue 3, Pages 151-162, 2009. 16. S. K. Bhullar and J.L. Wegner, “Some Transient Thermoelastic Plate Problems”, Journal of Thermal Stresses Volume 32, Issue 8, pages 768 – 790, Sept. 2009.

17. J.L. Wegner, M. M. Yao and S.K. Bhullar, “Dynamic wave-soil-structure interaction analysis of a two-way-asymmetric building system- DSSIA-3D”, Journal of Engineering and Technology Research Vol 1(2) pp.026-038, May 2009. 18. S. K. Bhullar and S.B.Singh, Thermo-elastic Problem of a Half- Space, Published in Bull. Cal. Math. Soc Vol. 99, no.6, 2007. 19. S. K. Bhullar, Thermal Stresses in a Hexagonal Region with an Elliptic Hole under a Heat Generation, Published in Journal of Nonlinear Dynamics and System Theory, An International Journal of Research and Surveys, Volume 6, pp. 245-256, 2006. Book Chapter 1. S.K. Bhullar and J. L. Wegner, “Thermal Spreading Resistance of an Isoflux Hyperellipse”, IAENG Transactions on Engineering Technologies, edited by American institute of physics, Chapter no.20, ISBN: 978-0-7354-0713-8,Volume 3,2009.

Book Introduction to Auxetic Materials and Application

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