Engineering topics

Hoffman, Christopher

Publications and source records attributed to Hoffman, Christopher.

3 records

DOE OSTI2015

MarFS, Version 1

There is a sea (mar is Spanish for sea) of data out there that needs to be handled efficiently. Object Stores are filling the hole of managing large amounts of data efficiently. However, in many cases, and our HPC case in particular, we need a traditional file (POSIX) interface to this data as HPC I/O models have not moved to object interfaces, such as Amazon S3, CDMI, etc.Eventually Object Store providers may deliver file interfaces to their object stores, but at this point those interfaces are not ready to do the job that we need done. MarFS will glue together two existing scalable components: a file system's scalable metadata component that provides the file interface; and existing scalable object stores (from one or more providers). There will be utilities to do work that is not critical to be done in real-time so that MarFS can manage the space used by objects and allocated to individual users.

ECP↗

NASA NTRS2008

High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suite Gas Processing System (GPS) Carbon Dioxide Scrubber

In support of the GPS for the SAM instrument suite built by NASA/GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr alloy wire, 0.0142 cm diameter, for use as a heater element for the carbon dioxide scrubber. The element would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The element also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni- 20Cr in low pressure CO2, coupled with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the element reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

Hoffman, Christopher↗

NASA NTRS2008

High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber

In support of the GPS for the SAM instrument suite built by GSFC, a life test facility was developed to test the suitability of 80Ni-20Cr wire, 0.0056 inches in diameter, for use as a heater element for the carbon dioxide scrubber. The wire would be required to operate at 1000 C in order to attain the 800 C required for regeneration of the getter. The wire also would need to operate in the Mars atmosphere, which consists mostly of CO2 at pressures between 4 and 12 torr. Data on the high temperature degradation mechanism of 80Ni-20Cr in low pressure CO2, together with the effects of thermal cycling, were unknown. In addition, the influence of work hardening of the wire during assembly and the potential for catastrophic grain growth also were unknown. Verification of the wire reliability as defined by the mission goals required the construction of a test facility that would accurately simulate the duty cycles in a simulated Mars atmosphere. The experimental set-up, along with the test protocol and results will be described.

Gundersen, Cynthia↗