The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

M. Singh - One of the best experts on this subject based on the ideXlab platform.

  • In-Space Repair of Reinforced Carbon-Carbon Thermal Protection System Structures
    2013
    Co-Authors: M. Singh
    Abstract:

    Advanced repair and refurbishment technologies are critically needed for the RCC-based thermal protection system of current space transportation system as well as for future Crew Exploration Vehicles (CEV). The damage to these components could be caused by impact during ground handling or due to falling of ice or other objects during launch. In addition, in-orbit damage includes micrometeoroid and orbital debris impact as well as different factors (weather, launch acoustics, shearing, etc.) during launch and re-entry. The GRC developed GRABER (Glenn Refractory Adhesive for Bonding and Exterior Repair) material has shown multiuse capability for repair of small cracks and damage in reinforced carbon-carbon (RCC) material. The concept consists of preparing an Adhesive Paste of desired ceramic with appropriate Adhesives and then applying the Paste to the damaged/cracked area of the RCC composites with Adhesive delivery system. The Adhesive Paste cures at 100-120 C and transforms into a high temperature ceramic during simulated entry conditions. A number of plasma torch and ArcJet tests were carried out to evaluate the crack repair capability of GRABER materials for Reinforced Carbon-Carbon (RCC) composites. For the large area repair applications, PLASTER (Patch Laminates and Sealant Technology for Exterior Repair) based systems have been developed. In this presentation, critical in-space repair needs and technical challenges as well as various issues and complexities will be discussed along with the plasma performance and post test characterization of repaired RCC materials.

  • In-Space Repair and Refurbishment of Thermal Protection System Structures for Reusable Launch Vehicles
    2007
    Co-Authors: M. Singh
    Abstract:

    Advanced repair and refurbishment technologies are critically needed for the thermal protection system of current space transportation systems as well as for future launch and crew return vehicles. There is a history of damage to these systems from impact during ground handling or ice during launch. In addition, there exists the potential for in-orbit damage from micrometeoroid and orbital debris impact as well as different factors (weather, launch acoustics, shearing, etc.) during launch and re-entry. The GRC developed GRABER (Glenn Refractory Adhesive for Bonding and Exterior Repair) material has shown multiuse capability for repair of small cracks and damage in reinforced carbon-carbon (RCC) material. The concept consists of preparing an Adhesive Paste of desired ceramic with appropriate additives and then applying the Paste to the damaged/cracked area of the RCC composites with an Adhesive delivery system. The Adhesive Paste cures at 100-120 C and transforms into a high temperature ceramic during reentry conditions. A number of plasma torch and ArcJet tests were carried out to evaluate the crack repair capability of GRABER materials for Reinforced Carbon-Carbon (RCC) composites. For the large area repair applications, Integrated Systems for Tile and Leading Edge Repair (InSTALER) have been developed and evaluated under various ArcJet testing conditions. In this presentation, performance of the repair materials as applied to RCC is discussed. Additionally, critical in-space repair needs and technical challenges are reviewed.

  • Glenn Refractory Adhesive for Bonding and Exterior Repair (GRABER) Developed for Repairing Shuttle Damage
    2005
    Co-Authors: M. Singh, Tarah Shpargel
    Abstract:

    Advanced in-space repair technologies for reinforced carbon/carbon composite (RCC) thermal protection system (TPS) structures are critically needed for the space shuttle Return To Flight (RTF) efforts. These technologies are also critical for the repair and refurbishment of thermal protection system structures of future Crew Exploration Vehicles of space exploration programs. The Glenn Refractory Adhesive for Bonding and Exterior Repair (GRABER) material developed at the NASA Glenn Research Center has demonstrated capabilities for repair of small cracks and damage in RCC leading-edge material. The concept consists of preparing an Adhesive Paste of desired ceramic in a polymer/phenolic resin matrix with appropriate additives, such as surfactants, and then applying the Paste into the damaged or cracked area of the RCC composite components with caulking guns. The Adhesive Paste cures at 100 to 120 C and transforms into a high-temperature ceramic during simulated vehicle reentry testing conditions.

  • On-Orbit Repair of RCC Structures
    2004
    Co-Authors: M. Singh
    Abstract:

    On-orbit repair technologies for reinforced carbon-carbon composite (RCC) structures are critically needed for space shuttle return to flight (RTF) efforts. These technologies are also critically needed for the repair and refurbishment of thermal protection system of future Crew Entry Vehicles (CEV) of space exploration programs. GRABER (Glenn Adhesive Refractory for Bonding and Exterior Repair) has shown multiuse capability for in-space repair of both large repairs and small cracks in space shuttle Reinforced Carbon Carbon (RCC) leading edge material. The concept consists of preparing an Adhesive Paste and then applying the Paste tot he damaged/cracked area of the RCC composites with caulking gun. The Adhesive Paste cures at 100-120 C and transforms into a high temperature ceramic during vehicle re-entry conditions. Further development and testing are underway to optimize the materials properties and extend the application temperature.

Ching-ping Wong - One of the best experts on this subject based on the ideXlab platform.

  • fast preparation of printable highly conductive polymer nanocomposites by thermal decomposition of silver carboxylate and sintering of silver nanoparticles
    ACS Applied Materials & Interfaces, 2010
    Co-Authors: Rongwei Zhang, Kyoungsik Moon, Ching-ping Wong
    Abstract:

    We show the fast preparation of printable highly conductive polymer nanocomposites for future low-cost electronics. Highly conductive polymer nanocomposites, consisting of an epoxy resin, silver flakes, and incorporated silver nanoparticles, have been prepared by fast sintering between silver flakes and the incorporated silver nanoparticles. The fast sintering is attributed to: 1) the thermal decomposition of silver carboxylate—which is present on the surface of the incorporated silver flakes—to form in situ highly reactive silver nanoparticles; 2) the surface activation of the incorporated silver nanoparticles by the removal of surface residues. As a result, polymer nanocomposites prepared at 230 °C for 5 min, at 260 °C for 10 min, and using a typical lead-free solder reflow process show electrical resistivities of 8.1 × 10−5, 6.0 × 10−6, and 6.3 × 10−5 Ω cm, respectively. The correlation between the rheological properties of the Adhesive Paste and the noncontact printing process has been discussed. With...

Giancarlo Di Gennaro - One of the best experts on this subject based on the ideXlab platform.

  • Scalp electrode placement by EC2 Adhesive Paste in long-term video-EEG monitoring.
    Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, 2005
    Co-Authors: Carolina Falco, Fabio Sebastiano, Lucia Cacciola, Fabio Orabona, Raffaella Ponticelli, Pamela Stirpe, Giancarlo Di Gennaro
    Abstract:

    Abstract Objective To evaluate the usefulness of an Adhesive Paste named EC2 ® (Grass-Telefactor) in comparison with collodion, for scalp electrodes placement in patients with drug resistant partial epilepsy monitored by long-term video-EEG. Methods A total of 40 patients with drug resistant partial epilepsy participated in the study. In 20 patients, electrode placement on the scalp was made with collodion (group C) whereas in the remaining patients EC2 ® was used (Group P). After the electrode placement (T1) and after 24h of recording (T2), the impedance of the electrodes was measured. Moreover, the time required to apply the electrodes and for their daily maintenance was calculated and recorded for all patients who entered the study. Results At each observation, group C showed mean values of electrode impedance significantly higher that the group P (T1: 16.8kΩ; T2: 6.5kΩ vs T1: 2.4kΩ; T2: 4.0kΩ, respectively) ( P −5 ). The time required to make the montage and to provide its daily maintenance was significantly shorter in group P than in group C [20.8 and 10.5min vs 44.3 and 19.7min, respectively ( P −5 )]. Conclusions We found that the use of EC2 Paste in scalp electrode attachment is less time consuming, with better recording quality as a result of lower electrode impedance values, than the use of collodion. Significance EC2 Paste may substitute collodion in electrode placement for long-term video-EEG monitoring, with an optimal cost-benefit ratio in terms of recording performance, time consumption, and safety.

Irccs Neuromed - One of the best experts on this subject based on the ideXlab platform.

  • Scalp electrode placement by EC2~Adhesive Paste in long-term video-EEG monitoring
    Dkgest of the World Latest Medical Information, 2005
    Co-Authors: Irccs Neuromed
    Abstract:

    Objective: To evaluate the usefulness of an Adhesive Paste named EC2(Grass-Telefactor) in comparison with collodion, for scalp electrodes placement in patients with drug resistant partial epilepsy monitored by long-term video-EEG. Methods: A total of 40 patients with drug resistant partial epilepsy participated in the study. In 20 patients, electrode placement on the scalp was made with collodion (group C)-whereas in the remaining patients EC2was used (Group P). After the electrode placement (T1) and after 24 h of recording (T2), the impedance of the electrodes was measured. Moreover, the time required to apply the electrodes and for their daily maintenance was calculated and recorded for all patients who entered the study. Results: At each observation, group C showed mean values of electrode impedance significantly higher that the group P (T1: 16.8 kΩ; T2: 6.5 kΩvs T1: 2.4 kΩ; T2: 4.0 kΩ, respectively) (P 1×10-5). The time required to make the montage and to provide its daily maintenance was significantly shorter in group P than in group C [20.8 and 10.5 min vs 44.3 and 19.7 min, respectively (P 1×10-5)]. Conclusions: We found that the use of EC2 Paste in scalp electrode attachment is less time consuming, with better recording quality as a result of lower electrode impedance values, than the use of collodion. Significance: EC2 Paste may substitute collodion in electrode placement for long-term video-EEG monitoring, with an optimal cost-benefit ratio in terms of recording performance, time consumption, and safety.

Zalyan G - One of the best experts on this subject based on the ideXlab platform.