9,056 research outputs found
Gas dispersion measurements using a mobile Raman lidar system
The exploitation of natural gas resources to supply energy demands has resulted in the need to engineer pipelines and plants capable of handling extremely high pressures and throughputs. Consequently, more attention has been directed to evaluating the consequences of releases of material whether accidental or deliberate in nature. An important aspect of assessing the consequences of a release is an understanding of how gas disperses in the atmosphere over a wide range of release and atmospheric conditions. The most cost effective way of providing such information is through the development and use of reliable theoretical prediction methods. The need for some form of remote sensing device was identified. The various possibilities studied led to the conclusion that LIDAR (Light Detection And Ranging) offered the most suitable method. The system designed and built is described, and its recent use in monitoring operational ventings from a high pressure transmission system is discussed
Influence of coherent mesoscale structures on satellite-based Doppler lidar wind measurements
Efforts to develop display routines for overlaying gridded and nongridded data sets are discussed. The primary objective is to have the capability to review global patterns of winds and lidar samples; to zoom in on particular wind features or global areas; and to display contours of wind components and derived fields (e.g., divergence, vorticity, deformation, etc.). Current considerations in support of a polar orbiting shuttle lidar mission are discussed. Ground truth for a shuttle lidar experiment may be limited to fortuitous alignment of lidar wind profiles and scheduled rawinsonde profiles. Any improvement on this would require special rawinsonde launches and/or optimization of the shuttle orbit with global wind measurement networks
Models for pattern formation in somitogenesis: a marriage of cellular and molecular biology
Somitogenesis, the process by which a bilaterally symmetric pattern of cell aggregations is laid down in a cranio-caudal sequence in early vertebrate development, provides an excellent model study for the coupling of interactions at the molecular and cellular level. Here, we review some of the key experimental results and theoretical models related to this process. We extend a recent chemical pre-pattern model based on the cell cycle Journal of Theoretical Biology 207 (2000) 305-316, by including cell movement and show that the resultant model exhibits the correct spatio-temporal dynamics of cell aggregation. We also postulate a model to account for the recently observed spatio-temporal dynamics at the molecular level
Improved laboratory gradiometer can be a field survey instrument
Improvements made to quartz gradiometer minimize or eliminate disturbing effects from known error sources and permit sensitivity of + or - 1 times 10 to the minus 9th power/sec sq or better and measuring accuracy of + or - 5 times 10 to the minus 9th power/sec sq
Equality, diversity and prejudice in Britain: results from the 2005 National Survey
Britain is an increasingly diverse and multifaceted society.
Consequently, manifestations of inequality, prejudice and
discrimination are potentially becoming more varied and
complex. The meaning of equality itself is a matter of
considerable debate. Perceptions, attitudes, stereotypes
and emotions permeate social relationships between
groups, whether conflictual or harmonious. How are
different groups perceived? How do images of different
groups map onto prejudice? To what extent do people
experience prejudice directed against themselves? There
is increasing interest in whether Britain is becoming a
more or less tolerant, accepting or indeed coherent
society.
This report describes the findings of a survey which
employed social psychological methods and measures to
assess a range of different aspects of prejudice towards
six significant groups in British society – defined by
gender, age, ethnicity, sexuality, disability and religion.
The report examines the values people espouse, their
experiences, and their expressions of prejudice, the
extent that ‘political correctness’ may affect expressions
of prejudice, the social stereotypes underpinning
prejudice, whether prejudice is expressed differently
towards different types of group, and the extent to which
British society is perceived as a cohesive whole or as
being formed of distinct and separate groups. It also
explores whether prejudice is predominantly an issue of
personal attitudes or whether it is rooted more in the
relationships between particular social groups
Laboratory measurements of forward and backward scattering of laser beams in water droplet clouds
Many aspects of the forward and backward scattering in dense water droplet clouds were studied using a laboratory scattering facility. This system is configured in a lidar geometry to facilitate comparison of the laboratory results to current lidar oriented theory and measurements. The backscatter measurements are supported with simultaneous measurements of the optical density, mass concentration, and droplet size distribution of the clouds. Measurements of the extinction and backscatter coefficients at several important laser wavelength have provided data on the relationship between these quantities for laboratory clouds at .633, 1.06, and 10.6 microns. The polarization characteristics of the backscatter of 1.06 microns were studied using several different types of clouds. More recently, the laboratory facility was modified to allow range-resolved backscatter measurements at 1.06 microns. Clouds made up of 3 layers, each with its own density, can be constructed. This allows the study of the effect of cloud inhomogeneity on the forward and backscatter
Gravity gradient preliminary investigations, part 2: Lunar tidal gravity gradients and stresses (exhibit C)
Preliminary analysis of the gravity gradients associated with gravity tides on the moon caused by the earth indicates that the relative changes in the gradients are very irregular, and large, and about 15 times greater than those experienced on earth. Thus gradients, in preference to gravity tides themselves, may well be an important key in correlating tide effects with lunar transient events and moonquakes, and also in determining triggering mechanisms for crustal movement and faulting. Preliminary analysis of lunar crustal stresses and strains caused by lunar gravity tides indicates that these factors may be more direct causative agents or triggering mechanisms. In particular, the cubic dilation undergoes relatively large changes and is about 11 times greater on the moon than on earth. Thus it should be correspondingly more important
Application of the ERTS system to the study of Wyoming resources with emphasis on the use of basic data products
Many potential users of ERTS data products and other aircraft and satellite imagery are limited to visual methods of analyses of these products. Illustrations are presented from Wyoming studies that have employed these standard data products for a variety of geologic and related studies. Possible economic applications of these studies are summarized. Studies include regional geologic mapping for updating and correcting existing maps and to supplement incomplete regional mapping; illustrations of the value of seasonal images in geologic mapping; specialized mapping of such features as sand dunes, playa lakes, lineaments, glacial features, regional facies changes, and their possible economic value; and multilevel sensing as an aid in mineral exploration. Examples of cooperative studies involving botanists, plant scientists, and geologists for the preparation of maps of surface resources that can be used by planners and for environmental impact studies are given
Gravity gradient preliminary investigations on exhibit ''A'' Final report
Quartz microbalance gravity gradiometer performance test
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