BIC 3, the Latest Inertial Centrifugal Balance for Mass Measurement in Weightless ConditionsRivetti, Antonio; Martini, Giovanni; Alasia, Franco; La Piana, Gaetano; Gatti, Laura
doi: 10.1007/s12217-007-9003-2pmid: N/A
The paper describes BIC 3, the latest prototype of inertial balance made at INRIM (former IMGC–CNR) in view of its possible use on board the International Space Station. The main characteristic of this instrument is its ability to work both in weightless conditions and on Earth surface with metrological performances comparable to those of a laboratory-level classic balance. BIC 3, although still based on the same centrifugal method adopted in the two previous prototypes, widely differs from them as regards configuration (constant speed), main motor characteristics (here a stepping motor is used), force transducer (the integral beam of a commercially-available balance), and consequently shows metrological performances considerably improved. The main constructional features are described and the metrological characteristics resulted from on-Earth tests are reported and discussed. A test made of 175 measurements in the range 0–150 g showed an expanded uncertainty of 4.1 mg.
Taking Plateau into Microgravity: The Formation of an Eightfold Vertex in a System of Soap FilmsBarrett, D.; Kelly, S.; Daly, E.; Dolan, M.; Drenckhan, W.; Weaire, D.; Hutzler, S.
doi: 10.1007/s12217-007-9001-4pmid: N/A
The microgravity phases of parabolic flights were used to perform experiments with soap films trapped in wire frames, a variation of the wire frame experiments originally designed by the nineteenth century Belgian scientist Joseph Plateau. We considered the formation of an eightfold vertex of Plateau borders within a cubic frame. In terrestrial experiments such a vertex can only be formed when liquid is forced through the Plateau borders, but in microgravity we found this vertex to be stable under equilibrium (non-flow) conditions once the liquid volume fraction exceeds 0.022 ± 0.005. This is consistent with the theoretical value for the transition, which for our experiment we estimate to be 0.0192.
Antibody-based Detection of Escherichia coli O157:H7 and Salmonella enterica Serovar Typhimurium Grown in Low-shear Modeled MicrogravityNyquist-Battie, Cynthia; Freeman, Laura; Leckband, Kristen; Martinez, Stephanie; Ansley, Ariel; Lund, Deanna; Lim, Daniel
doi: 10.1007/s12217-007-9002-3pmid: N/A
With the advent of prolonged spaceflights, it is important to determine if antibody-based assays can be used to monitor food and water for bacterial contaminants. In the present work, a ground-based high aspect ratio vessel (HARV) was used to determine if low shear modeled microgravity (LSMMG) alters antibody-binding to E. coli O157:H7 and Salmonella enterica serovar Typhimurium. Antibody–bacteria binding was similar under LSMMG and normal gravity because there was no difference in amount of captured bacteria measured by colony forming units (CFU) between assays conducted in the HARV and a conventional roller flask. The ability of E. coli O157:H7 and Salmonella Typhimurium grown in LSMMG to bind specific antibodies was also studied. After incubations of 4, 18 or 36 h in the HARV or a shaking incubator, bacteria were harvested for enzyme-linked immunosorbent assays (ELISA). In the E. coli O157:H7 ELISA using a goat polyclonal primary antibody, LSMMG did not alter the linear range of detection (105–107 cells/ml) nor the signal to noise ratio at any bacterial concentration. Although insignificant changes in signal to noise ratios were evident, LSMMG did not alter the range of detection (105–107 cells/ml) for Salmonella Typhimurium in ELISAs using either a polyclonal or a monoclonal antibody. These results suggest that immunoassays may be used in spacecrafts because LSMMG does not have significant deleterious effects on antibody-binding to bacteria nor does it significantly alter surface antigens necessary for antibody-based methods.