A5031614977- Muscle activation and electromyography studies
- Heat Transfer and Optimization
- Heat Transfer and Boiling Studies
- Prosthetics and Rehabilitation Robotics
- Refrigeration and Air Conditioning Technologies
- Balance, Gait, and Falls Prevention
- Diabetic Foot Ulcer Assessment and Management
- Musculoskeletal pain and rehabilitation
- Spacecraft and Cryogenic Technologies
- Fluid Dynamics and Turbulent Flows
- Ergonomics and Musculoskeletal Disorders
- Shoulder Injury and Treatment
- Mechanical Circulatory Support Devices
- Heat Transfer Mechanisms
University of Colorado Boulder
2015-2018
National Renewable Energy Laboratory
2013-2014
Sloped walking is challenging for individuals with transtibial amputation (TTA) due to the functional loss of ankle plantarflexors. Prostheses that actively generate power may help restore this lost function. The purpose study was use musculoskeletal modeling and simulation quantify mechanical delivered body segments by passive powered prostheses remaining muscles in amputated intact legs during sloped walking. We generated simulations from experimental kinematic kinetic data on slopes 0, ±3...
A study was conducted to experimentally characterize the pool boiling performance of hydrofluorocarbon HFC-245fa at pressures ranging from 0.15 MPa 1.1 (reduced pressure range: 0.04–0.31). Pool experiments were using horizontally oriented 1-cm2 heated surfaces quantify effects and a microporous-enhanced coating on heat transfer coefficients critical flux (CHF) values. Results showed that enhanced CHF by 430% 50%, respectively. The then compared with HFC-134a hydrofluoroolefin HFO-1234yf.
This study evaluates a jet impingement based cooling strategy combined with microfinned enhanced surfaces as means of improving thermal management for power electronic devices. For comparison, baseline channel flow heat exchanger and on plain are characterized. The jets, augmented surfaces, provide localized to areas heated by the insulated-gate bipolar transistors diode Lighter materials simpler manufacturing while managing required pumping increase overall performance reducing weight,...
People with a transtibial amputation using passive-elastic prostheses exhibit reduced prosthetic ankle power and push-off work compared to non-amputees compensate by increasing their affected leg (AL) hip joint unaffected (UL) ankle, knee, during level-ground walking. Use of powered ankle-foot prosthesis normalizes step-to-step transition walking over range speeds for people amputation, but the effects on level-ground, uphill downhill have not been assessed. We investigated how use affect...
Experiments were conducted to evaluate the use of a passive two-phase cooling strategy as means automotive power electronics. The proposed approach utilizes an indirect configuration alleviate some reliability concerns and allow conventional modules. An inverter-scale proof-of-concept system was fabricated tested using refrigerants hydrofluoroolefin HFO-1234yf hydrofluorocarbon HFC-245 fa. Results demonstrated that can dissipate at least 3.5 kW heat with 250 cm <sup...
A study was conducted to experimentally characterize the pool boiling performance of hydrofluorocarbon (HFC)-245fa. The motivation for this research is candidate refrigerants potential use in automotive power electronics two-phase cooling systems. HFC-245fa experiments were using horizontally oriented 1-cm2 heated surfaces quantify effects pressure and a microporous-enhanced coating on heat transfer coefficients critical flux (CHF) values. Experiments carried out at pressures ranging from...
Sacroiliac joint (SI) dysfunction is present in 15-30% of individuals with low back pain. Pain the SI often disturbs typical gait patterns. One hypothesis regarding cause a lack coactivation between latissimus dorsi and contralateral gluteus maximus, which together provide force closure sacrum ilium. Latent muscle synergies during movement can be identified principal component analysis on EMG signals. Components eigenvalues (EV) greater than 1.0 significantly explain portion covariance...