Laser Acoustics Laboratory

The Laser Acoustics Lab (500 square feet) houses optical systems for materials characterization and nondestructive testing. The lab houses a high frequency (1 GHz) acoustic microscopy system incorporating a pulsed picosecond laser for acoustic wave generation and a stabilized Michelson interferometer for detection. The system incorporates a precision gimbal mount on a three-axis translation stage (50nm resolution) allowing for the inspection of MEMs and nanoscale materials systems.

The lab is also equipped with a photorefractive based holographic interferometry system for the detection of ultrasound on optically rough surfaces. Additional equipment includes: a Continuum Q-switched Nd:YAG laser operating at 1064nm and frequency doubled to 532nm, a high speed (1.6 GHz) oscilloscope, high speed photodetectors, a 200mW Lightwave CW low noise frequency doubled Nd:YAG laser, 2 GHz amplifiers, and several computer workstations. The lab is currently focused on the following research areas:

• High-resolution laser ultrasonics for nanoscale materials characterization: In this project near-field optical techniques are used in conjunction with our acoustic microscopy system to increase the spatial resolution to the nanometer scale. The goal of this effort is to measure the thermomechanical properties of nanoscale structures having lateral feature sizes on the order of 100nm or less.
  
  
• Laser ultrasonic inspection of ceramic coatings: This effort uses our laser based ultrasonic system to measure the thermomechanical properties of ceramic thermal barrier coatings and environmental barrier coatings. The laser-based system will also be used to material degradation (micro-cracking, phase transformations) during thermal cycling.
  
  
• Optoacoustic imaging: The objective of the proposed research is to develop and assess a laser array system for high resolution, broadband optoacoustic imaging system. Applications of proposed OAI system include cancer detection and differentiation, real-time monitoring of noninvasive surgical procedures, and the measurement of optical properties of tissue.

Back to top

Lithotripsy and Acoustic Levitation Laboratory

The Lithotripsy and Acoustic Levitation Lab (approx. 300 square feet) houses a research lithotripter used for experiments involving the physical acoustics of acoustic shock waves and the manner in which they can be used to destroy kidney stones. The unit comes equipped with an electro-hydraulic shock wave generator coupled to an instrumented test tank. Acoustical and optical cavitation detection systems are used to sense bubble activity generated by shock waves. There is also a high-pressure chamber with acoustically transparent windows that is equipped with acoustic and optical ports to allow for the study of shock wave interaction with stones under pressure. The objective is to assess the role played by cavitation in breaking up the stones.

The Lab also houses the Drop Physics Module, an acoustic levitation apparatus that flew on the Space Shuttle in the Spacelab module during the missions STS-50 (First United States Microgravity Laboratory, USML-1) and STS-73 (USML-2). The apparatus enabled the study of drop dynamics and surface rheology in micro-gravity.

Current Sponsored Research Projects:

• Role of cavitation in lithotripsy: This project focuses on trying to understand the role of cavitation bubbles in breaking up kidney stones and damaging tissue.
  
  
• Pattern formation, transport and breakup via surface wave instabilities: We levitate soap bubbles in the DPM, and induce parametric capillary-waves in the thin film layer and study their properties.
  
  
• Foam rheology II: Dry foam dynamics: We levitate and oscillate spheroidal foam samples in the DPM, where their size will be an order of magnitude larger than in our ultrasonic levitation experiments.

Back to top

Nonlinear and Biomedical Acoustics Laboratory

The Nonlinear and Biomedical Acoustics Laboratory Lab (approx. 550 square feet) is a fully-equipped wet lab (sink, fume hood, refrigeration, electronic mechanical fabrication) which currently houses several ongoing experiments each utilizing water-filled, fully-instrumented test tanks, as well as independent computer-based data acquisition systems wedded to electronic instrumentation packages generally designed for the generation amplification, and detection of ultrasonic waves. Also employed are systems for spatially and temporally resolved thermal dosimetry and PIV flow visualization in tissue phantoms (acoustic hemostasis experiments), laser Mie-scattering systems for monitoring radial bubble motion (cavitation-enhanced hyperthermia) and high-power sound sources for experiments in the use of high-intensity focused ultrasound (HIFU) for medical therapy.

The Lab is also used for experiments involving extracorporeal shock-wave lithotripsy. It houses an instrumented water tank facility coupled to instrumentation for the generation and detection of intense shock waves. Sources include a 170 element high-power piezoelectric array. The facility is also used for mapping out the nonlinear acoustic field of ultrasound transducers that are used in medical ultrasound imaging devices. A small tank is available for measuring longitudinal and shear wave propagation in elastic solids.

Current Sponsored Research Projects:

• High Intensity Focused Ultrasound for Acoustic Hemostasis: We investigate the use of ultrasound to for the rapid elevation of temperature in vascularized media. The application is the use to ultrasound to control bleeding from blunt trauma injury.
  
  
• The Role of Bubbles in Enhancing Acoustic Hyperthermia in a Tissue Mimicking Phantom: We investigate how cavitation can enhance our ability to heat tissue with ultrasound.
  
  
• Experiments on the nonlinear acoustics of ultrasonic lithotripsy—the breaking of kidney stones by shock waves: In this project the impact of stone geometry and material properties are assessed to determine how they affect the ability of shock waves to break stones.
  
  
• The Scanning Acoustic Microscope: A super-high resolution instrument for probing the acoustic properties of biological tissue.

Back to top

Physical Acoustics Laboratory

The Physical Acoustics Laboratory (approx. 400 square feet) is devoted to sponsored research into the various mechanisms and effects of the interaction of sound and ultrasound with matter, specifically fluids and fluid interfaces. General topics of interest include acoustic levitation, nonlinear bubble and drop dynamics, interfacial wave phenomena, sonoluminescence, ultrasonic techniques for probing surface, and bulk rheology for Newtonian and Non-Newtonian fluids.

The lab currently houses 2 ongoing experiments, each utilizing independent, computer-based data acquisition systems interfaced to electronic instrumentation packages generally designed for the generation, amplification, and detection of ultrasonic and interfacial waves. Several acoustic levitation devices have been fabricated for non-contact isolation/excitation of bubbles in water and drops in air. Also employed are systems for active acoustic scattering, laser-scattering systems for monitoring bubble and drop motion, and high-speed digital imaging systems.

Current Sponsored Research Projects:

• Sonoluminescence in Space: We investigate the role of gravity in the phenomenon of Sonoluminescence, which is the emission of short pulses of light by nonlinearly oscillating bubbles in acoustic levitators.
  
  
• Foam Rheology Near the Order-Disorder Transition: We investigate the properties of acoustically levitated aqueous foams (like soap suds) as a function of gas volume fraction.

Back to top

Underwater Acoustics & Ultrasound Laboratory

The Underwater Acoustics and Ultrasound Laboratory (approx. 1500 square feet) focuses on the propagation of sound in natural bodies of water. The facility, located in the basement of 110 Cummington Street, includes fabrication facilities, a wet lab testing facility with computer-controlled instrumentation for acoustic propagation experiments. The lab also contains two workstations for computational modeling. In addition to lab and computational efforts, the underwater sound group is involved in field and large-tank research projects through collaborations with other regional facilities. Soon to come online is a large wooden test tank (approx. 12’ x 10’ x 8’ deep) for scale acoustic tests, educational investigations, and transducer calibration and evaluation.

The current research thrust of the underwater sound group is the study of sound propagation in the shallow water surf zone. Ongoing projects include the characterization of acoustic propagation through bubble clouds. An in situ device has been developed to measure the acoustic impedance of bubbly assemblages and (eventually) the sea bottom. An additional study is underway to investigate the dynamics of individual bubble suspended in a viscoelastic holding medium. This project incorporates laser Mie scattering as a means to non-invasively measure bubble response to acoustic forcing.
Also housed in the basement lab is the Medical Imaging Testbed (MedBED) of the NSF Center for Subsurface Sensing and Imaging Systems (CenSSIS). This facility boasts two instrumented test tanks: a large tank for general purpose experiments in linear and nonlinear ultrasound imaging and a small tank that supports a 75 MHz Scanning Acoustic Microscope (SAM). A full-featured ultrasound imaging system donated to the Lab by Analogic Corporation will come on line. This facility supports a broad range of biomedical imaging activity under way at Boston University and the other CenSSIS partner institutions.

Current Sponsored Research Projects:

• A Sound-Hard Impedance Tube for the Measurement of the Frequency-Dependent Complex Impedance of Bubbly Mixtures: We study the unique acoustical properties of bubbly liquids using a classic technique for characterizing the acoustical properties of reflective surfaces.
  
  
• The Dynamics of Single Bubbles in Viscoelastic Media: Using a viscoelastic gel to "suspend" a bubble and laser diagnostics, we study the linear dynamics of an acoustically driven bubble.
  
  
• Acoustic Scattering from Bubbly Assemblages (in conjunction with the Naval Undersea Warfare Center Acoustic Test Facility): The bubble theme continues, but this time we develop instrumentation to take to the Naval Undersea Warfare Center’s Acoustic Test Facility (Newport, R.I.) to do a series of totally unique experiments in acoustic scattering from bubble clouds.
  
  
• A Ultrasound Test Facility for the CenSSIS Medical Imaging Testbed (MedBED): This is a general-use facility that forms part of a network of experimental testbeds within the NSF Center for Subsuface Sensing and Imaging Systems (CenSSIS).
  
  
• Tissue Harmonic Imaging: This CenSSIS project addresses the use of nonlinear acoustics principles to improve our ability to do biomedical imaging with ultrasound.
  
  
• Acousto-Photonic Imaging: We investigate how light and sound can interact to improve our ability to do optical imaging in diffuse media.

Back to top

Dynamics and Control Laboratory

The Dynamics and Control Laboratory serves introductory, intermediate, and advanced courses in dynamics, vibrations, and controls. Laboratory exercises for EK 302 Engineering Mechanics II and AM 441 Mechanical Vibrations in mechanical oscillatory systems have been developed to provide experimental verification of theoretical concepts introduced in lectures. Laboratory exercises for AM 403 Atmospherics Flight Mechanics and AM 404 Dynamics and Control of Mechanical Systems will allow the testing of analysis and design techniques for the feedback control of aeronautical and mechanical systems.

Two computer-controlled cart and pendulum systems are currently operational. For dynamics and vibrations classes, they can be used individually to demonstrate principles of dynamics. Feedback control can be used to study the effects of varying the apparent mechanical properties of the systems. Dynamic coupling of the individual systems can also be achieved through computer control. Experiments developed for the Aerospace and Mechanical Engineering control classes (AM 403 and AM 404) will focus on applying design and analysis tools. Stability and performance specifications will be emphasized.

In addition, the lab contains a controllable airfoil to be used in AM 403 Atmospheric Flight Mechanics to study aircraft stability and control. A second system consists of a flexible two-floor structure similar to a building. Accelerometers and motor-driven carts are included on each floor. This system can be used in EK 302, AM 441, AM 403, and AM 404 to explore the concepts of flexible systems, modal analysis, MIMO (multi-input multi-output) control and vibration dammping. Approximately 500 square feet of space is specifically dedicated to this instructional laboratory.

Back to top

The Intelligent Mechatronics Laboratory

The Intelligent Mechatronics Laboratory is a 1,000 square foot facility located in the Aerospace and Mechanical Engineering Building at 110 Cummington Street. It is home to the students and research efforts of Professors Hua Wang, Pierre Dupont, and John Baillieul. The mission of the laboratory is to develop new control and information technologies to support advanced applications in robotics surgery, coordinated control of autonomous robot vehicles, control of complex mechanical systems (e.g. fluids and arrays of micro-actuators). Current projects, included in the following list, are described in detail in the laboratory's web pages, which may be accessed from http://iml.bu.edu:

• Medical robotics (optimal port placement for minimally invasive surgery, image guided surgery)
  
• Communicating mobile robotics
  
• Contact sensing (modeling by manipulation)
  
• Structural dynamics (mechanical realization, MEMS filter)
  
• Control of fluids
  
• Friction analysis (friction modeling)
  
• Networked control systems
  
• Sensor networks
  
• Tactile display (multichannel vibrotactile display)
  
• Control of mechanical systems

Back to top

Boundary Layer Wind Tunnel

This facility is designed for studying turbulent transport phenomena in two-dimensional and three-dimensional boundary layer flows. Measurement capabilities include two component Laser Doppler Velocimetry, hot-wire anemometry for three dimensional velocity measurements, cold-wire temperature instrumentation, and laser light sheet flow visualization. Past research projects have included 3-D scalar transport studies in the junction boundary layers, flow visualization of vortex generator jets, and turbulent flow field mapping of shallow wall cavities.

Back to top

Instrumentation, Aerodynamics & Fluid Mechanics Laboratory

This 2,600 square foot undergraduate instructional laboratory contains a large, computer-controlled wind tunnel for experiments related to flow induced pressures and forces on shpheres, cylinders, and airfoils; and a small wind tunnel for experiments related to Bernoulli's Principle. It also contains equipment for studying the flow of water in pipes, the characteristics of pumps, and the transition from laminar to turbulent flow. In addition, the laboratory is equipped with computer work stations with associated electronic meters for automated sata acquisition fromm transducers used for measuring temperature, strain, displacement, and flow rate.

Back to top

Thermodynamics, Heat Transfer & Propulsion Laboratory

The Thermodynamics, Heat Transfer, and Propulsion Laboratory’s primary function is to provide laboratory components for the thermal science courses, EK 304 Energy and Thermodynamics, AM 419 Heat Transfer, and AM 405 Propulsion. The laboratory consists of the following equipment and experiments:

• A steam boiler and steam power plant, used for two exercises in EK 304: (a) Measurement of saturated steam properties and application of the first law of thermodynamics for a closed system, and (b) Application of the first law of thermodynamics for an open system.
  
• An instrumented double-wall heat exchanger apparatus for heat exchanger and convection experiments in AM 419 involving determination of the overall heat transfer coefficient, the heat transfer coefficients of the individual streams, the heat exchanger effectiveness, and temperature profiles through the heat exchangers.
  
• Constant temperature baths, instrumented metal spheres and a DAQ computer for an unsteady heat transfer experiment, involving measuring the temperature-time history of both a copper sphere and a steel sphere moved between temperature baths.
  
• An operating mini jet engine, fully instrumented for computer data acquisition.

Back to top

Nanometer Scale Engineering Laboratory

The Nanometer Scale Engineering Laboratory is located in the Metcalf Science and Engineering Building, within the Boston University Nanoscale Research Facility. Nanometer scale semiconductor mechanical devices are fabricated here using electron beam lithography, plasma and wet etching techniques. After fabrication, various state-of-the-art characterization techniques are employed to study the physical processes dominant in these nanomechanical devices. Among the fundamental phenomena studied are dissipation, fluctuations and surface effects at nanometer length scales.

The practical aspects of this research involve the design and fabrication of ultra-high speed nano-mechanical sensors, and development of surface nano-engineering techniques for improved device characteristics. The extreme sensitivity of these nanometer scale devices necessitates in situ characterization in Ultra High Vacuum (UHV). A UHV Surface Analysis System has recently been installed in the lab, with surface modification capabilities such as thermal annealing and ion beam milling, and various surface analysis tools including Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM). In addition, optical interferometry techniques are being developed for ultra-sensitive displacement sensing in nanomechanical devices. The high operation frequencies of these devices extending into the microwave bands necessitate developing and employing high frequency electronics and techniques.

Back to top

Precision Engineering Research Laboratory

The Precision Engineering Laboratory study focuses on sensing, control, and fabrication at the limits of achievable precision. Areas of interest include microelectromechanical systems (MEMS), nanometer-scale actuation, micromachining, design of optical arrays, and microfluidics. Current projects include MEMS deformable mirrors, spatial light modulators, film stress modification, microvalve arrays, adaptive optics systems, tip-tilt mirror arrays, MEMS hydrophones, and networked control systems.

Back to top

CAD Lab

The Computer Aided Design (CAD) Laboratory is primarily used by students taking AM 311 Engineering Design Using CAD, AM 312 Fundamentals of Engineering Design, and EK 130 Introduction to Engineering. An area within the lab is designated as the senior capstone area. This part of the lab supports the senior design courses AM 409 Flight Vehicle Design I, AM 410 Flight Vehicle Design II, AM 413 Machine Design I, and AM 414 Machine Design II, augmenting the SCUD lab. Other students may use the area, but preference is given to seniors. The CAD lab is 1,500 square feet in area.

It is the general policy of the lab to support any department course that uses software either directly as part of the curriculum or indirectly as a resource for projects and homework. In this way, no student in the department is ever penalized for not having the financial resources to buy either a personal computer or the appropriate software to do their course work. Courses for which special software is maintained in the lab include EK 301 Engineering Mechanics I, AM 308 Structural Mechanics, AM 310 Instrumentation and Theory of Experiments, and EK 305 Mechanics of Materials. The lab’s internet access is used extensively for research by many students.

The lab is equipped with 30 top of the line PCs and many software packages, including AutoCAD Inventor, MATLAB, 3D Studio Max, C++, ALGOR, CME Frame, and Microsoft Office. Officially the lab is open a least 35 hours a week, but all the TAs are engineering students, and they often keep the Lab open well past the official closing time. Any student may work in the lab as long as a TA is present. The building is locked at 8:30pm, but students may use the phone on the front of the building to call the lab for access after hours.

Back to top

Fabrication Laboratory

The Fabrication Laboratory serves students in most of the engineering design courses of the Department (ENG AM 311 Engineering Design Using CAD, ENG AM 312 Fundamentals of Engineering Design, ENG AM 410, Flight Vehicle Design II, ENG AM 413 Machine Design I, and ENG AM 414 Machine Design II), as well as other courses in the Department with major mechanical design projects (ENG EK 301 Engineering Mechanics I, and ENG EK 305 Mechanics of Materials). The role of laboratory is to give our students space for hands-on experience with fabrication, starting from design drawings, of real physical objects that must perform as designed. Currently, the major machinery in the laboratory consists of 3 Sharp end mills with CNC control systems, two Sharp lathes, a band saw, some older drill presses, a table saw, a grinder and sander, and miscellaneous hand tools. The laboratory occupies 1305 sq. ft. in two adjacent rooms: ENG B02 and ENG B07 of 110 Cummington St. Its operation is under the supervision of the department’s laboratory supervisor and laboratory engineer.

Back to top

Graduate Computer Laboratory

The Graduate Computer Lab is equipped with 3 Sun Ultra 10 workstations. The lab also has a PC running Windows 2000, a scanner, and both a color laser printer and a black and white laser printer. Graduate students have 24/7 access to the lab.

Back to top

Mechanics of Materials Laboratory

This 600 square foot undergraduate instructioanl laboratory is equipped with a fully computer interfaced Instron Universal Testing Facility and a Charpy Impact Testing Apparatus for measuring the hardness, tensile, bending, and buckling properties of steel and aluminum beams and other solid material specimens.

Back to top

Senior Computational Design Lab (SCuD Lab)

The Senior Computational Design (SCUD) Laboratory serves students in the capstone design sequences of both the Aerospace Engineering program (ENG AM 409, Flight Vehicle Design I, and ENG AM 410, Flight Vehicle Design II) and in the Mechanical Engineering program (ENG AM 413, Machine Design I, and ENG AM 414, Machine Design II). The role of the SCUD Lab is to provide our seniors with sufficient computer power and software to be able to use modern engineering computational tools and methods in their design projects. Currently, the laboratory has 15 Dell Pentium IV computers – all web enabled – along with a server, a large format plotter, and three printers. The major software packages now installed on all laboratory computers include Pro/E suite, AutoDesk Inventor suite, FEMLab, algor, ANSYS multiphysics, AAA Design and Analysis, Xenon, MATLab with Simulink, MS Office, and MS Project. The SCUD Lab occupies a full-time dedicated space of approximately 370 square feet in Rm. 241 of 110 Cummington St. It is maintained by the department’s laboratory engineer.

Back to top

Senior Design Laboratory

The Senior Design Laboratory has been established to provide the equipment and space for the completion of the capstone design projects for both Aerospace and Mechanical Engineering. The facility consists of work stations and portable hand and power tools for the fabrication of various devices and pieces of equipment that have been designed by the students. This facility is also used to a lesser extent by other undergraduate courses where a design component requires fabrication. This lab is used primarily by students in AM 410 and AM 414.

Back to top