IEEE EMBS LIU Student Branch Chapter

Regulating Metabolic Energy Among Joints During Human Walking Using a Multiarticular Unpowered Exoskeleton

Regulating Metabolic Energy Among Joints During Human Walking Using a Multiarticular Unpowered Exoskeleton Researchers have found that the walking economy can be enhanced by recycling ankle metabolic energy using an unpowered ankle exoskeleton. However, how to regulate multiarticular energy to enhance the overall energy efficiency of humans during walking remains a challenging problem, as multiarticular....

Kidney stones are hard deposits made of minerals and salts that form inside your kidneys. Some types of kidney stones are removed with invasive surgical procedure. However, in some cases they can be removed with a non-invasive procedure: lithotripsy.

Lithotripsy treats certain types of kidney stones that are too large to pass through the urinary tract by breaking them into smaller ones. The procedure is done by sending focused ultrasonic energy or shock waves directly to the stone.

Lithotripsy consists of four main components:

• a shockwave generator:

Applying the inverse of piezoelectric effect is one way of generating the shockwave. This type of generation uses piezoelectric crystals that are set in a water-filled container. The crystals are stimulated via high frequency electrical pulses. The alternating stress/strain changes in the material create ultrasonic vibrations, resulting in the production of a shockwave.

• a focusing system:

The focusing system is used to direct the generator-produced shockwaves at a focal volume in a synchronous fashion.

• a coupling mechanism:

In the propagation and transmission of a wave, energy is lost at interfaces with differing densities. As such, a coupling system is needed to minimize the dissipation of energy of a shockwave as it traverses the skin surface.

• an imaging/localization unit:

Localizing the stone to direct the shockwaves is an important step. The two commonly used imaging methods for this include fluoroscopy and ultrasonography. These are also important in tracking the progress of the treatment and making alternations as the stone fragments.