3,977 research outputs found
Surveys of the earth's resources and environment by satellites
The potential and promise of observing the earth from the vantage point of space is discussed. The systematic surveying of processes and phenomena occurring on the surface of the earth by Landsat 1 and Nimbus 5 is considered to be useful in the following areas: assessment of water resources; mineral and petroleum exploration; land use planning; crop, forest, and rangeland inventory; assessment of flood, earthquake, and other environmental hazards; monitoring coastal processes; environmental effects of industrial effluents and of air pollution; mapping the distribution and types of ice covering the earth's polar caps and global soil moisture distributions
Traditional Cultural Districts: An Opportunity for Alaska Tribes to Protect Subsistence Rights and Traditional Lands
Alaska tribes have limited control over their traditional lands and waters. Tribes may increase their influence through a Traditional Cultural District designation under Section 106 of the National Historic Preservation Act. This designation does not stop development, but requires federal agencies to consult with tribes regarding potential development that may impact the district. The consultation right applies regardless of whether a tribe owns or has formally designated the district. In Alaska, where no Traditional Cultural Districts exist as of 2014, there is potential for designating large areas of land or water that correspond to the range of traditionally important species
Investigation of resin systems for improved ablative materials Interim report, 10 Jan. - 1 Jul. 1966
Preparation, and evaluation of polyimide sulfone resins, graphite-silica reinforced polyamide resins, and resin resistance to FLOX- methane, and fluorine-hydrogen fuel
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Thermal dehydroxylation of porous glass
The thermal removal of hydroxyl groups from porous glass tubing depends on both temperature and time. The general relationship between these two parameters and the residual hydroxyl content in 96 % SiO2 (by weight) reconstructed glass was determined by subjecting porous glass tubes to various temperatures in vacuum and in dry air. The temperature for maximum removal of water decreases as the hold time increases. The optimum temperatures result from a balance in rates of water diffusion and glass sintering which retards diffusion. Increasing the total pressure of the atmosphere surrounding the porous glass during the degassing cycle decreases the net degassing rate. The role of other factors such as composition of the porous glass and pore structure are briefly mentioned
Knowledge creation and management in the five LHC experiments at CERN: implications for technology innovation and transfer
The present study analyses knowledge creation, acquisition and transfer in the five LHC physics experiments at CERN: ALICE, ATLAS, CMS, LHCb, and TOTEM. A questionnaire was provided during collaboration meetings and a total of 291 replies were obtained and analysed. The results of this research study provide evidence that the social process of participation in meetings, acquisition of skills in different areas, and the development of interests by interaction with colleagues are key elements of the learning process. Furthermore, the results indicate that knowledge acquisition in a multicultural environment plays a mediating role in the interaction between social capital constructs (social interaction, relationship quality, and network ties) and competitive advantage outcomes (invention development and technological distinctiveness). Social interaction, relationship quality, and network ties are connected to greater knowledge acquisition, and also contribute to innovation and transfer of the knowledge to industry. The fertile environment of the five LHC experiments building and managing multiple processes, involves a dynamic, interactive,and simultaneous exchange of knowledge both inside and outside their organization
A statistical analysis of the fatigue behaviour of single and multi-spot welded joints
Several models exist for predicting the fatigue behaviour of a spot welded joint based on geometric data.However, the accuracy of these models tends to diminish as the number of spot welds and complexityof the joint increases. This paper reports on the findings of an investigative study to assess the applicabilityof a statistical approach to modelling the fatigue behaviour of multi-spot welded joints, based on dataobtained from testing single spot welded joints that are geometrically equivalent to the individual weldsin the multi-spot joint. A range of fatigue tests were carried out using Staircase and Probit techniquesto determine the fatigue strength distribution of a range of multi-spot welded joints, which were subsequentlycompared to those predicted using the proposed statistical model. The comparison indicated an excellentcorrelation between predicted and experimentally determined values for standard deviation and a marginaldifference for mean fatigue strength values. This difference is potentially attributed to the effects of a degreeof load redistribution occurring part way through testing in the multi-spot joints, which is currentlynot adequately accounted for in the proposed statistical model
Electrical Cell-Substrate Impedance Spectroscopy Can Monitor Age-Grouped Human Adipose Stem Cell Variability During Osteogenic Differentiation
: Human adipose stem cells (hASCs) are an attractive cell source for bone tissue engineering applications. However, a critical issue to be addressed before widespread hASC clinical translation is the dramatic variability in proliferative capacity and osteogenic potential among hASCs isolated from different donors. The goal of this study was to test our hypothesis that electrical cell-substrate impedance spectroscopy (ECIS) could track complex bioimpedance patterns of hASCs throughout proliferation and osteogenic differentiation to better understand and predict variability among hASC populations. Superlots composed of hASCs from young (aged 24-36 years), middle-aged (aged 48-55 years), and elderly (aged 60-81 years) donors were seeded on gold electrode arrays. Complex impedance measurements were taken throughout proliferation and osteogenic differentiation. During osteogenic differentiation, four impedance phases were identified: increase, primary stabilization, drop phase, and secondary stabilization. Matrix deposition was first observed 48-96 hours after the impedance maximum, indicating, for the first time, that ECIS can identify morphological changes that correspond to late-stage osteogenic differentiation. The impedance maximum was observed at day 10.0 in young, day 6.1 in middle-aged, and day 1.3 in elderly hASCs, suggesting that hASCs from younger donors require a longer time to differentiate than do hASCs from older donors, but young hASCs proliferated more and accreted more calcium long-term. This is the first study to use ECIS to predict osteogenic potential of multiple hASC populations and to show that donor age may temporally control onset of osteogenesis. These findings could be critical for development of patient-specific bone tissue engineering and regenerative medicine therapies.
SIGNIFICANCE: Human adipose stem cells (hASCs) are an appealing cell source for bone tissue engineering and regenerative medicine applications because they can be obtained in high quantities via liposuction procedures and can differentiate down musculoskeletal lineages. However, a major barrier to clinical translation of hASCs is that cells from different donors have varying capacities to proliferate and differentiate. This study used electrical impedance spectroscopy to noninvasively track osteogenic differentiation of age-grouped donors in real time, showing that age-grouped hASCs have distinct complex impedance patterns. This method could be used to improve understanding of the biology that causes variability among hASC populations and to provide quantitative quality control standards for hASC populations in stem cell manufacturing and bone tissue engineering applications
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