Habitability: CAMELOT 4

During 1988 to 1989 the NASA/USRA Advanced Design Program sponsored research and design efforts aimed at developing habitability criteria and at defining a habitability concept as a useful tool in understanding and evaluating dwellings for prolonged stays in extraterrestrial space. The Circulating Auto sufficient Mars-Earth Luxurious Orbital Transport (CAMELOT) was studied as a case in which the students would try to enhance the quality of life of the inhabitants by applying architectural design methodology. The study proposed 14 habitability criteria considered necessary to fulfill the defined habitability concept, which is that state of equilibrium that results from the interaction between components of the Individual Architecture Mission Complex, which allows a person to sustain physiological homeostatis, adequate performance, and acceptable social relationships. Architecture, design development, refinements and revisions to improve the quality of life, new insights on artificial gravity, form and constitution problems, and the final design concept are covered

Internal and relative motions of the Taurus and Ophiuchus star-forming regions

We investigate the internal and relative motions of the Taurus and Ophiuchus star-forming regions using a sample of young stars with accurately measured radial velocities and proper motions. We find no evidence for expansion or contraction of the Taurus complex, but a clear indication for a global rotation, resulting in velocity gradients, this suggests a common origin, possibly related to that of Gould's Belt.Comment: 2 figure

Debris/ice/TPS assessment and integrated photographic analysis for Shuttle Mission STS-56

The Debris Team developed and implemented measures to control damage from debris in the Shuttle operational environment and to make the control measures a part of routine launch flows. These measures include engineering surveillance during vehicle processing and closeout operations, facility and flight hardware inspections before and after launch, and photographic analysis of mission events. Photographic analyses of mission imagery from launch, on-orbit, and landing provide significant data in verifying proper operation of systems and evaluating anomalies. In addition to the Kennedy Space Center (KSC) Photo/Video Analysis, reports from JSC, MSFC, and Rockwell International--Downey are also included in this document to provide an integrated assessment of the mission

Commensurate-Incommensurate Magnetic Phase Transition in Magnetoelectric Single Crystal LiNiPO4_4

Neutron scattering studies of single-crystal LiNiPO$_4$ reveal a spontaneous first-order commensurate-incommensurate magnetic phase transition. Short- and long-range incommensurate phases are intermediate between the high temperature paramagnetic and the low temperature antiferromagnetic phases. The modulated structure has a predominant antiferromagnetic component, giving rise to satellite peaks in the vicinity of the fundamental antiferromagnetic Bragg reflection, and a ferromagnetic component giving rise to peaks at small momentum-transfers around the origin at $(0,\pm Q,0)$. The wavelength of the modulated magnetic structure varies continuously with temperature. It is argued that the incommensurate short- and long-range phases are due to spin-dimensionality crossover from a continuous to the discrete Ising state. These observations explain the anomalous first-order transition seen in the magnetoelectric effect of this system

Giant Magnetoelectric Effect in a Multiferroic Material with a High Ferroelectric Transition Temperature

We present a unique example of giant magnetoelectric effect in a conventional multiferroic HoMnO3, where polarization is very large (~56 mC/m2) and the ferroelectric transition temperature is higher than the magnetic ordering temperature by an order. We attribute the uniqueness of the giant magnetoelectric effect to the ferroelectricity induced entirely by the off-center displacement of rare earth ions with large magnetic moments. This finding suggests a new avenue to design multiferroics with large polarization and higher ferroelectric transition temperature as well as large magnetoelectric effects

Estabilización de suelo arcilloso utilizando materiales cementicios activados alcalinamente

In this study, a clayey soil classified as A-7-5 according ASTM D3282, was stabilized using alkali-activated cementitious materials (AAC) added to the soil dry in percentages of 20 and 30%. Fly ash (F1, F2) with high unburned carbon content (up to 38.76%), hydrated lime (L) and granulated blast furnace slag were used. Unconfined compressive strength and flexural strength at 28 days of curing and the durability after 12 wetting-drying cycles were evaluated. The results were compared with a soil-cement reference mixture. The soil treated with AAC-F1L showed a volume expansion of 0.51% and volume contraction of -0.57% compared with the 0.59% expansion and -0.68% contraction of the soil-cement reference mixture. Additionally, the mass loss after the wetting and drying cycles is only 3.74% which is slightly lower than the mass loss of the soil stabilized with ordinary Portland cement (OPC) (3.86%) and well below the value specified in Colombian regulations (7%).En este estudio, un suelo arcilloso clasificado como A-7-5 según ASTM D3282, se estabilizó utilizando materiales activados alcalinamente (AAC) en porcentajes de 20 y 30%. Se utilizaron cenizas volantes (F1, F2) con alto contenido de inquemados (hasta 38,76%), cal hidratada (L) y escoria granulada de alto horno. Se evaluó la resistencia a la compresión confinada y la resistencia a la flexión a 28 días de curado y la durabilidad después de 12 ciclos de humectación-secado. Los resultados se compararon con una mezcla de referencia suelo-cemento. El suelo tratado con AAC-F1L mostró una expansión y contracción volumétrica del 0,51% y -0,57% respectivamente, en comparación con el 0,59% y -0,68% de la mezcla de referencia suelo-cemento. Además, la pérdida de masa después de los ciclos de humectación y secado es sólo 3.74%, valor ligeramente inferior a la del suelo estabilizado con cemento Portland (3.86%) y muy inferior al valor especificado en la normativa colombiana (7%)

Manifestation of finite temperature size effects in nanogranular magnetic graphite

In addition to the double phase transition (with the Curie temperatures T_C=300K and T_{Ct}=144K), a low-temperature anomaly in the dependence of the magnetization is observed in the bulk magnetic graphite (with an average granular size of L=10nm), which is attributed to manifestation of the size effects below the quantum temperature. The best fits of the high-temperature data (using the mean-field Curie-Weiss and Bloch expressions) produced reasonable estimates for the model parameters, such as defects mediated effective spin exchange energy J=12meV (which defines the intragranular Curie temperature T_C) and proximity mediated interactions between neighboring grains (through potential barriers created by thin layers of non-magnetic graphite) with energy J_t=exp(-d/s)J=5.8meV (which defines the intergranular Curie temperature T_{Ct}) with d=1.5nm and s=2nm being the intergranular distance and characteristic length, respectively