Orthopaedic Bioengineering Research Laboratory (OBRL)

Our bodies are machines for living. – Leo Tolstoy

The application of solid mechanics to the field of medicine has greatly increased our knowledge of orthopedic pathologies and lead to some of the most successful treatments and implants used in surgery.  This is especially relevant in contemporary society because of the aging population will exponentially  increase the incidence and complication of orthopaedic conditions.  The mission of CSU’s Orthopaedic Bioengineering Research Laboratory (OBRL) is to significantly impact the practice of orthopaedic surgery through basic science discovery and highly translational research.

The OBRL uses both state-of-the-art computational (such as finite element)and experimental (such as biaxial tension)techniques to study the mechanical etiology of orthopaedic disease states, and, using this information, design effective treatment strategies.  The OBRL is co-located and closely aligned with CSU’s Veterinary Teaching Hospital and their clinical faculty to facilitate the bench top-to-clinic translation of our research.

These research activities have been recognized by the awarding of major federal grants (by the National Institutes of Health and the National Aeronautic and Space Administration) and national awards.  In addition, we work closely with many of the major orthopaedic companies.  As an example of our work, recent CSU Mechanical Engineering Ph.D. student Kevin Troyer developed  a fully non-linear and computationally tractable viscoelastic formulation to describe the time-dependent behavior of orthopaedic soft tissues (such as ligament and tendon).  His dissertation project led to the publication of no less than 5 manuscripts in some of the leading biomechanics journals.

Next Generation Photovoltaics Center

W. S. Sampath, Professor of Mechanical Engineering

The Mechanical Engineering Department’s Materials Engineering Lab (MEL) under the direction of Professor W.S. Sampath has been in the forefront of CdTe photovoltaic manufacturing technology development since 1991. Numerous pieces of equipment and processes have been developed for synthesis and testing of photovoltaic devices. These include:

  • Facilities for measuring film thickness
  • Clean room mini-environment for substrate preparation and automated cleaning
  • Spray metallization for back electrode formation
  • Fabrication facilities for small area device fabrication and analysis
  • Accelerated Lifetime Testing (ALT) of devices under automated high illumination and high temperature cycling
  • Exposing and testing devices under outdoor conditions emulating sealed modules
  • Device characterization including dark JV, light JV, CV, CF, TAS, TID, PHCAP etc. and the capability to perform these as a function of temperature using a cryostat

Student Fabricating PV Devices

Figure 1. Student fabricating PV devices with the Advanced Deposition System

The recently completed Advanced Deposition System (ADS) (see Figure 1) provides a process-flexible, customizable test bed for producing complete devices on 3 inch by 3 inch or smaller substrates. Completed in August 2010, the system has already produced several hundred unique samples for a variety of research projects and for process optimization. Execution of process sequences is computer-controlled for maximum repeatability and precision using a magnetic transfer arm. The substrate can be moved in any sequence and any combination of process times into 9 different sources. This flexibility provides for rapid process optimization using prototype sources.
The ADS is in continual use and provides tens of completed substrates and hundreds of individual cells each week for a variety of projects and process-optimization studies. Figure 2 shows the ADS system schematic. The magnetic transfer arm can move the substrate to any deposition station for any period of time, allowing for wide process flexibility.

Advanced Deposition System (ADS) Figure 2 Schematic of the Advanced Deposition System (ADS)
In addition to the ADS, the MEL has three other vacuum deposition systems: (i) RF/Pulsed DC deposition system, (ii) thin film deposition by co-sublimation from two sublimation sources, and (iii) plasma deposition system.
These facilities will enable advancing the CdTe PV technology from the current device technology shown in the left in Figure 3 to the one in the middle and then to the device structure shown on the right. Research to advance the device technology to reach the device structure in the middle in Figure 3 is actively being pursued at CSU with promising results.

Schematic of current and future advanced device structuresFigure 3: Schematic of current and future advanced device structures (η = cell efficiency)

The laboratory has received funding from the National Science Foundation, Dept. of Energy and Industry. Students design and build PV devices and test them

Advanced Materials Processing Lab

researchlabs_AMPTimageMechanical Engineering Assistant Professor Troy Holland, recently converted a warehouse at CSU’s Mechanical Engineering Research Center into the Advanced Materials Processing Testing Lab. The AMPT Lab specializes in creating functional materials using metals, ceramics, and polymers, via sintering.

Introducing this lab seemed like the appropriate next step in developing and diversifying materials research at CSU, especially with the School of Advanced Materials Discovery on the horizon. Currently, there are a variety of projects underway in the lab. Graduate students in charge of each project make an effort to manufacture the best material possible for any given application.

  • Modeling and testing the densification behavior(s) of functionally/mechanically graded oxide ceramics undergoing applied thermal gradients > 600 K/cm. Graduate students: Paul Colasuonno, Corson Cramer
  • Producing hydroxyapatite composites for creating tougher bone replacements using 2-D materials (much like graphene) as reinforcements and comparing them with unreinforced and nanotube reinforcements. Graduate student: Trevor Aguirre
  • Creating various foam, both syntactic and normal shape memory alloys to evaluate the mechanical performance in self-healing and elastocaloric applications. Graduate student: Peter Nivala
  • Investigating the effects of applied, low-frequency loads on the creep and sintering behavior of ceramic materials. Graduate student: David Anderson
  • Understanding the effects of applied electric fields on densification behaviors, as well as novel methods of manufacturing electride materials. Graduate student: Tom Hammann
  • Designing, manufacturing, and testing ultrahigh temperature-capable heat exchangers (>1473 K) using low-cost materials and techniques. Graduate student: Vincent Torres
  • Designing an additive manufacturing technique for metals and ceramics using sintering approaches and methods quite different than anything currently available. Graduate student: Tucker Hensen

Creating ceramic and metal-based materials that operate mechanically and functionally at high temperatures is the lab’s overall goal, says Dr. Holland. The AMPT Lab sets itself apart from other materials labs with new techniques and equipment that give the lab a singular ability to function synergistically, both theoretically and practically.

Dr. Holland is optimistic for the future of his lab, but specifically, he hopes to understand theoretical issues surrounding sintering and creep sufficiently to enable true scalability to industrially relevant sizes for ceramic and metal parts.

Biomaterials Surface Micro/Nano-Engineering Laboratory

Dr. Ketul Popat, Assistant Professor of Mechanical Engineering

researchlab_biomaterialssurfaceimageSurfaces that contain micro- and nanoscale features in a well-controlled and “engineered” manner have been shown to significantly affect cellular and subcellular function. Within the auspices of the our research program, we are developing, refining and extending select fabrication routes for producing materials with controlled nanoarchitecture and bioactivity, potentially moving us closer to the goal of biointegration. Of great interest is the creation of controlled micro- and nanoarchitectures in an attempt to mimic the natural physical and biological environment that encourages tissue regeneration and growth. The hypothesis is that the nanoarchitectures can promote cell differentiation and functionality. Moreover, the ability to create model nanodimensional constructs that mimic physiological systems can aid in studying complex tissue interactions in terms of cell communication, response to matrix geometry, and effects of external chemical stimuli. By understanding how physical surface parameters influence cellular adhesion and differentiation we can more effectively design biomaterial surfaces for variety of tissue engineering applications. Further, nanostructured materials can be used as drug eluting interfaces for implantable devices, such as vascular stents, orthopedic implants, dental implants, etc. By precisely controlling the size of nanoarcitecture, we can manipulate the release rates; thus releasing the drug at physiological levels.

Biomaterials Research and Engineering Laboratory (BREL) lab

researchlab_BRELImageWork in BREL focuses on characterization and development of biomaterial solutions to health care problems. Dr. James’ and her colleagues hold several patents on novel technologies for orthopedic and cardiovascular applications. For example, BioPoly® is a family of hyaluronan/polyethylene materials invented by Dr. James’ group which are currently being used commercially in femoral condyle partial resurfacing devices (http://www.biopolyortho.com/) and have been implanted in several patients in the UK. Ongoing research is now expanding the BioPoly platform for use as blood-contacting materials such as flexible leaflets in heart valves and small diameter vascular grafts. Other projects in the group include the development of phospholipid-based coatings that enhance osseointegration and allow for controlled drug delivery. An in vivo animal study has already demonstrated the efficacy of these coatings on titanium implants in fighting osteomyelitis, and current studies are examining the efficacy of these coating on polymeric implants and allograft bone.

Director, Susan P. James, Professor and Head, Mechanical Engineering, Professor, Biomedical Engineering

Associate Director, David Prawel, Sr. Research Scientist, Mechanical Engineering, Biomedical Engineering