In-Vehicle Evaluation of Milled Rumble Strips in Pre– and Post–Chip Seal Maintenance Periods

Driver fatigue and drowsiness can have a profound impact on safety. Centerline and shoulder rumble strips are popular countermeasures designed to produce audible and tactile warning when vehicles deviate from the travel lane onto the rumble strips. These warnings reduce the risk of lane departure crashes. Studies show that the noise produced by rumble strips is a function of many variables. Rumble strip depth is known to have the greatest impact in alerting drivers. However, chip seal pavement maintenance operations tend to reduce the original rumble strip design depth, which may have an impact on the functional effectiveness of the rumble strips. The purpose of this study was to conduct a controlled experiment to understand the relationship between milled rumble strip depth and noise and vibration in the vehicle cab. In-vehicle noise and vibration levels were collected on rumble strips of five depths (⅛, ¼, ⅜, ½, and ⅝ in.) and three types (shoulder, single centerline, and double centerline) on three highways in the state of Nebraska by two vehicles traveling at speeds of 45, 55, and 65 mph. Rumble strip depths at ⅛-in. intervals were used to simulate the influence of a chip seal on rumble strip effectiveness. From the in-vehicle sound and vibration levels of all the tested rumble strip depths, it can be hypothesized that a ⅛-in. reduction in the current milled rumble strip design depth, as a result of chip sealing, would not cause a practical reduction in the effectiveness of rumble strips producing audible and tactile warnings to alert drivers.

Biocompatible encapsulation and interconnection technology for implantable electronic devices

A biocompatible packaging process for implantable electronic systems is under development at imec, combining biocompatibility, hermeticity, extreme miniaturization and cost aspects. In a first phase of this packaging sequence, hermetic chip sealing is performed by encapsulating all chips to realize a bi-directional diffusion barrier preventing body fluids to leach into the package causing corrosion, and preventing IC materials such as Cu to diffuse into the body, causing various adverse effects. For cost effectiveness, this chip sealing is performed as post-processing at wafer level, using modifications of standard clean room (CR) fabrication techniques. Well known conductive and insulating CR materials are investigated with respect to their biocompatibility, biostability, diffusion barrier properties and sensitivity to corrosion. Material selection and integration aspects are modified until good properties are obtained. In a second phase of the packaging process, all chips of the final device should be electrically connected, applying a biocompatible metallization scheme. We selected the use of Pt due to its excellent biocompatibility and corrosion resistance. Since Pt is very expensive, a cost effective Pt-selective plating process is developed. During the third packaging step, all system components such as electronics, passives, a battery,… will be interconnected. To provide sufficient mechanical support, all components are finally embedded using a medical grade elastomer such as PDMS or Poly-urethane.

Design and Characterization of a Biocompatible Packaging Concept for Implantable Electronic Devices

A biocompatible packaging process for implantable electronic systems is described, combining biocompatibility and hermeticity with extreme miniaturization. In Phase 1 of the total packaging sequence, all chips are encapsulated in order to realize a bidirectional diffusion barrier, preventing body fluids from leaching into the package, which would cause corrosion, and preventing IC materials such as Cu from diffusing into the body, which would cause various adverse effects. For cost-effectiveness, this hermetic chip sealing is performed as a postprocessing step at the wafer level using modifications of standard clean room (CR) fabrication techniques. Well-known conductive and insulating CR materials are investigated with respect to their biocompatibility, diffusion barrier properties, and sensitivity to corrosion. In Phase 2 of the packaging process, all chips of the final device should be electrically connected, applying a biocompatible metallization scheme using, for example, gold or platinum. For electrodes in direct contact with the tissue after implantation, IrOx metallization is proposed. Phase 3 of device assembly is the final packaging step, during which all system components, such as electronics, passives, a battery, among others, will be interconnected. To provide sufficient mechanical support, all these components are embedded using a biocompatible elastomer such as PDMS.

Design and characterization of a biocompatible packaging concept for implantable electronic devices

A biocompatible packaging process for implantable electronic systems is described, combining biocompatibility and hermeticity with extreme miniaturization. In a first phase of the total packaging sequence, all chips are encapsulated in order to realize a bi-directional diffusion barrier preventing body fluids to leach into the package causing corrosion, and preventing IC materials such as Cu to diffuse into the body, causing various adverse effects. For cost effectiveness, this hermetic chip sealing is performed as post-processing at wafer level, using modifications of standard clean room (CR) fabrication techniques. Well known conductive and insulating CR materials are investigated with respect to their biocompatibility, diffusion barrier properties and sensitivity to corrosion. In a second phase of the packaging process, all chips of the final device should be electrically connected, applying a biocompatible metallization scheme using eg. gold or platinum. For electrodes being in direct contact with the tissue after implantation, IrOx metallization is proposed. Device assembly is the final packaging step, during which all system components such as electronics, passives, a battery,… will be interconnected. To provide sufficient mechanical support, all these components are embedded using a biocompatible elastomer such as PDMS.