241 research outputs found

    Faculty Characteristics That Are Associated With the Retention of Doctoral Students.

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    The primary purpose of this study was to elicit perceptions of doctoral-student advisors regarding issues and processes associated with graduate dissertation research experiences in the schools of vocational education. A mailed survey was sent to teacher educators from the 21 member institutions of the University Council for Vocational Education (UCVE) who had served as chair to at least one doctoral committee. A researcher-designed instrument which used selected scales from other research was sent to the survey population. Statistical analyses were conducted on 144 completed surveys which represented a usable response rate of 76%. The completion rate among faculty\u27s doctoral-student advisees was 76%. Significant associations with completion rate were identified as: tenure status, academic rank, advisor\u27s age, advisor\u27s gender, and whether or not faculty had a primary vocational area of Agricultural Education. A unique finding of this study was that the advisors\u27 experience in the profession was found to explain the greatest portion of the variability in the overall student completion rate. Stepwise regression analysis was used to identify a model consisting of 4 variables that explained 44% of the variability in completion rate. Tenure status provided 32% of the explanatory power of the model, academic rank provided 5%, and number of current doctoral-student committees advisors reported serving on as chairperson and the number of international completers advised explained another 7% of the explanatory power of the model. The researcher recommends that faculty development programs be implemented that would utilize the experienced faculty as mentors of new faculty in areas of doctoral-student advising. It is recommended that additional variables of investigation be identified through conducting qualitative research activities with faculty and graduate students using techniques such as focus groups, focus universities, and/or Delphi panels. It is concluded that the number of doctoral-student committees advisors reported currently serving on as chairpersons was negatively related to the overall doctoral-student completion rate. It is recommended that departments make faculty aware that the greater number of doctoral-student committees faculty currently served on as chairpersons might be a deterrent for their students\u27 retention in the program

    Sintering of Lunar and Simulant Glass

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    Most oxygen-extraction techniques are temperature-dependent, with higher temperatures resulting in higher oxygen yield. An example is hydrogen reduction, in which the optimum process temperature is 1050 C. However, glass-rich lunar soil begins to show the effects of sintering at temperatures of 900 C or lower. Sintering welds particles together due to viscous relaxation of the glass in the sample. One approach to avoid problems related to sintering, such as difficulty in removing waste material from the reactor, is to keep the soil in motion. One of several methods being studied to accomplish this is fluidized-bed processing techniques, in which the grains are kept in motion by the action of flowing reductant gas. The spent material can be removed from the chamber while still fluidized, or the fluidizing motion can continue until the material has cooled below approx. 500 C. Until end-to-end prototypes are built that can remove the heated soil, the most practical option is to keep the bed fluidized while cooling the waste material. As ISRU technology advances, another option will become valuable, which is to intentionally sinter the material to a great enough extent that it becomes a brick. The free iron in lunar soil is magnetic, and ferromagnetic bricks can be manipulated by robotic systems using electromagnetic end effectors. Finally, if an electromagnetic field is applied to the soil while the brick is being formed, the brick itself will become a magnet. This property can be used to create self-aligning bricks or other building materials that do not require fasteners. Although sintering creates a challenge for early lunar surface systems, knowledge gained during prototype development will be valuable for the advanced lunar outpost

    Possible Mafic Patches in Scott Crater Highlight the Need for Resource Exploration on the Lunar South Polar Region

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    Possible areas of mafic material on the rim and floor of Scott crater (82.1 deg S, 48.5 deg E) are suggested by analysis of shadow-masked Clementine false-color-ratio images. Mafic materials common in mare and pyroclastic materials can produce more oxygen than can highlands materials, and mafic materials close to the south pole may be important for propellant production for a future lunar mission. If the dark patches are confirmed as mafic materials, this finding would suggest that other mafic patches may exist, even closer to the poles, which were originally mapped as purely anorthositic

    Apollo 17 Lunar Sounder Data provide Insight into Aitken Crater's Subsurface Structure

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    In preparation for the forthcoming avalanche of data from Lunar Reconnaissance Orbiter (LRO), we conducted a pilot study to demonstrate integration of multiple geophysical data sets. We applied methods of data integration that are used by the commercial mineral exploration industry to enhance the value of historical data sets and to provide a roadmap for future efforts

    Evaluation for Intensive Home Community Based Services: A Program for At-Risk Youth and their Families

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    The purpose of this longitudinal evaluation study was to examine client perceptions of the Home Community Based Services Program (HCBS) located in two rural counties in Central Minnesota. It was hypothesized that adjudicated youth (ages 12-17), who have access to the HCBS Program may experience less out-of-home placements and less criminal re-offending. Data was collected utilizing two surveys, one at exit of services, and one six months after discharge of services. Findings indicated clients perceived the HCBS Program a positive experience introducing change in the family system. Less out-of-home placement was experienced for youth involved in the HCBS Program. The literature review formulated that a need exists for specialized intensive programs targeting high-risk youth. Previous research provided a construct supporting community based programs as intervention sites for high-risk youth and their families. Cost effectiveness gained relevance in conducting the literature search. The cost per residential placement for one youth is approximately 40,000peryear,(SocialServicesCensusReport,1995),HCBSProgram2˘7scost40,000 per year, (Social Services Census Report, 1995), HCBS Program\u27s cost 53,000 per year

    Mafic Materials in Scott Crater? A Test for Lunar Reconnaissance Orbiter

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    Clementine 750 nm and multispectral ratio data, along with Lunar Orbiter and radar data, were used to study the crater Scott in the lunar south polar region. The multispectral data provide evidence for mafic materials, impact melts, anorthositic materials, and a small pyroclastic deposit. High-resolution radar data and Lunar Orbiter photography for this area show differences in color and surface texture that correspond with the locations of the hypothesized mafic and anorthositic areas on the crater floor. This region provides a test case for the upcoming Lunar Reconnaissance Orbiter. Verification of the existence of a mafic deposit at this location is relevant to future lunar resource utilization planning

    Pneumatic System for Concentration of Micrometer-Size Lunar Soil

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    A report describes a size-sorting method to separate and concentrate micrometer- size dust from a broad size range of particles without using sieves, fluids, or other processes that may modify the composition or the surface properties of the dust. The system consists of four processing units connected in series by tubing. Samples of dry particulates such as lunar soil are introduced into the first unit, a fluidized bed. The flow of introduced nitrogen fluidizes the particulates and preferentially moves the finer grain sizes on to the next unit, a flat plate impactor, followed by a cyclone separator, followed by a Nuclepore polycarbonate filter to collect the dust. By varying the gas flow rate and the sizes of various orifices in the system, the size of the final and intermediate particles can be varied to provide the desired products. The dust can be collected from the filter. In addition, electron microscope grids can be placed on the Nuclepore filter for direct sampling followed by electron microscope characterization of the dust without further handling

    The Lunar Regolith as a Recorder of Cosmic History

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    The Moon can be considered a giant tape recorder containing the history of the solar system and Universe. The lunar regolith (soil) has recorded the early history of the Moon, Earth, the solar system and Universe. A major goal of future lunar exploration should be to find and play back existing fragments of that tape . By reading the lunar tape, we can uncover a record of planetary bombardment, as well as solar and stellar variability. The Moon can tell us much about our place in the Universe. The lunar regolith has likely recorded the original meteoritic bombardment of Earth and Moon, a violent cataclysm that may have peaked around 4 Gyr, and the less intense bombardment occurring since that time. This impact history is preserved on the Moon as regolith layers, ejecta layers, impact melt rocks, and ancient impact breccias. The impact history of the Earth and Moon possibly had profound effects on the origin and development of life. Decrease in meteor bombardment allowed life to develop on Earth. Life may have developed first on another body, such as Mars, then arrived via meteorite on Earth. The solar system may have experienced bursts of severe radiation from the Sun, other stars, or from unknown sources. The lunar regolith has recorded this radiation history in the form of implanted solar wind, solar flare materials and radiation damage. Lunar soil can be found sandwiched between layers of basalt or pyroclastic deposits. This filling constitutes a buried time capsule that is likely to contain well-preserved ancient regolith. Study of such samples will show us how the solar system has evolved and changed over time. The lunar tape recorder can provide detailed information on specific portions of solar and stellar variability. Data from the Moon also offers clues as to whether so-called fundamental constants have changed over time

    Preparation and Testing of Ice-Enriched Lunar Regolith Simulant for RESOLVE OVEN

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    The RESOLVE (Regolith and Environment Science and Oxygen and Lunar Volatile Extraction) project seeks to deploy a robotic ISRU lander at the lunar south pole to determine the accessibility of frozen ice and the resource potential at various locations. The OVEN (Oxygen and Volatiles Extraction Node) component will be used to heat samples to 150 C or higher in order to drive off ice and other volatiles, which will then be identified and measured. An ice volatilization system has been developed to specifically collect data on the extraction of water vapor from a sample. Testing of the system was begun in April of this year. This report addresses our current work to test the system in a relevant environment in this case, using simulants with up to 10wt% water ice at 76K, in reduced atmosphere

    Luminance and chromatic contributions to a hyperacuity task: Isolation by contrast polarity and target separation

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    AbstractVernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red–green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (−Lum−Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum−Chr) thresholds were only elevated close to isoluminance; in the reverse condition (−Lum+Chr), thresholds were elevated as in the −Lum−Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity
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