Active Projects
Comfortable, Easy-to-Insert Hearing Protection Earplug
Noise-Induced Hearing Loss (NIHL), typically resulting from cumulative exposure, is the most prevalent occupational injury in US industry, affecting more than 10 million workers at a total preventable economic cost of ~$100 billion. Most employers rely primarily on personal hearing protection devices to prevent injury. Foam “roll-down” earplugs are the most common and effective, offering high attenuation and unobtrusive all-day comfort. However, they are difficult to insert correctly, limiting their real-world performance and leaving a majority of wearers under-protected.
RAPA Technologies has developed a novel earplug that provides exceptional comfort and maximal passive attenuation but is much easier to insert correctly, more convenient, and incorporates a pass-through communications channel. This earplug will offer better protection when worn and be worn more often, substantially improving hearing conservation outcomes.
Rigid Envelope Bladder (patents pending)
Ultra-Pure, High Endurance Liquid Bladder with Volume Sensor
The NASA Portable Life Support System (PLSS) for the Exploration Extravehicular Mobility Unit (xEMU) incorporates a Feedwater Supply Assembly (FSA) to store consumable cooling water. The FSA must accept a total of 12 lbs of pure water prior to each Extra-Vehicular Activity (EVA), then supply this water to the cooling loop at ambient suit pressure during the EVA, functioning reliably for up to 15 years of service. To meet these requirements, NASA has specified multiple ultra-pure fluoropolymer bladders captured in restraints providing overpressure tolerance to 38 psi. The assembly must also conform to a defined geometric envelope. Unfortunately, designs to date have failed, for two primary reasons. First, typical constructions involving a lay-flat bladder captured within a sewn textile restraint do not use space efficiently enough to store the required volume within the available space. Second, wrinkles that form as the bladders inflate cause the fluoropolymer membrane to tear. Other challenges include robust mounting to a rigid structure and visual access for inspection.
RAPA Technologies has developed a novel rigid envelope bladder that meets all specifications for the FSA. The design combines the benefits of a flexible bladder with the strength and convenience of a rigid tank, providing an ultra-pure, ambient-pressure reservoir with high overpressure tolerance, high volumetric efficiency within arbitrarily shaped spaces, near-zero dead volume, optical transparency for visual inspection, simplified mounting, and low mass.