ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experiments in fluids 23 (1997), S. 193-201 
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A pH sensitive dye technique has been used to highlight the zones of greatest scalar concentration in a turbulent jet as color regions. Photographs taken with a motion picture camera showed circular zones of the width of the jet moving downstream. These expand downstream and lose color until they are only small patches and wisps of red. A scheme has been developed whereby the Lagrangian velocity of the most concentrated zones can be measured. These move regularly at constant or steadily decreasing speed along rays originating in the source. The speed is about twice that of the mean Eulerian velocity component.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experiments in fluids 16 (1993), S. 129-136 
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper describes an experimental study currently being conducted on the mixing in turbulent jets and plumes. The objective of this study is the description of the structure of turbulent flows from a coherent picture of the entrainment and mixing process. A pH sensitive dye is used to illuminate the three-dimensional structure of the flow, by identifying all fluid exceeding a predetermined concentration of source fluid. This is best described as a threshold technique since the specified concentration is located on the surface of the coloured fluid. This technique facilitates the examination of the interrelations of large and small turbulent structures through the observation of the instantaneous threshold contaminant distribution. Photographs have indicated that the source fluid of the jet is contained in thin sheets whose thickness is of the order of the Batchelor microscale; the distribution of which is fitted by a Gamma distribution. The spacing between the sheets is of the order of the Kolmogorov microscale. Observations of the colour distribution using a permanent inert dye in a jet showed that the Gaussian distribution cannot be a valid description of the concentration at the edges of the jet. The permanent dye photographs show that all of the contaminant is contained within an envelope of width 1.86b, whereb is the characteristic velocity radius. This observation led to a simple equation, based on the conservation of mass, for predicting the time averaged mean front location within the jet. This equation compares well to the experimental results. The normalized rms values of the concentration locations are also presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 1985-10-01
    Description: The variability of wood specific gravity and yield of 23 white spruce provenances from the Great Lakes – St. Lawrence forest region was studied 20 years after planting at Harrington Forest Farm, Québec. The results indicate no relationship between wood specific gravity of provenances and their respective growth performance. The southwestern section of this region showed a small decrease in wood specific gravity, but it was compensated for by a strong increase in volume growth, resulting in an important gain in dry weight productivity. The variability of white spruce wood specific gravity was split into three sources: 11% was attributed to provenance differences, 8% to provenance and repetition interaction, and the remainder to differences among trees of the same provenance and to experimental error. In a breeding program, a first selection should be made at the provenance level on the basis of volume productivity and a second selection on the basis of wood specific gravity values within the selected provenances, to maximize the overall genetic and economic gain.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2002-12-01
    Print ISSN: 0013-936X
    Electronic ISSN: 1520-5851
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 1993-12-01
    Print ISSN: 0723-4864
    Electronic ISSN: 1432-1114
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 1997-07-28
    Print ISSN: 0723-4864
    Electronic ISSN: 1432-1114
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 1987-07-01
    Description: During genetic sampling of white spruce in 1984, increment cores were taken from 80 populations in order to study wood density variation within species in natural Quebec forests. Results show that wood density differences exist between populations and that wood density is negatively correlated with the width of the growth rings; however, some trees and some populations exhibit both high wood density and rapid growth. A moderate positive link was found between juvenile and mature wood densities at both the individual and population levels. Therefore, breeding programs for the improvement of wood density could be based on selections made on juvenile wood.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 1990-02-01
    Description: Twenty years after planting, X-ray densitometry and immersion were used to determine the relative density of wood from 28 white spruce populations of the Great Lakes – St. Lawrence forest region. The results showed the same pattern of radial variation in all populations. Wood density decreases for the first few years of growth, then stabilizes for a time, then increases slowly, but steadily. The relative density of wood from white spruce has a slight, negative correlation with the width of the annual growth rings, at either the individual or the population level. However, some populations and individuals do deviate from this trend. Though the populations showed some statistically significant differences in relative density, analysis of variance showed that 85 to 90% was attributable to differences among trees within the same population. This study confirmed the desirability of using relative density as the basis for making mass selections within fast-growing white spruce populations to genetically improve the genetic quality of wood.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 1981-03-01
    Description: Survival and total height of red spruce (Picearubens Sarg.) at ages 15 and 22 years from seed are reported. Twelve provenances distributed from North Carolina to Quebec were grown in three experiments each in Ontario, Quebec, and New Brunswick; seven additional provenances were only partially represented. Variance, correlation, and regression analyses were made. Results at both ages were very similar. Provenance differences in survival were small at individual sites and significant only when the results from all nine sites were combined. Provenance differences in height were well expressed and significant in each of the three groups of tests, with northern provenances growing best. Several provenances were also relatively stable and performed well from site to site. Correlation and regression analyses showed that variation in height was more closely related to the degree of introgressive hybridization with black spruce (Piceamariana (Mill.) B.S.P.) than to latitude, elevation, or precipitation at the place of seed origin. These results were conditioned by development on open sites which are not typical red spruce sites.In contrast with expectations when the study was initiated, it is now apparent that provenances from the southern Appalachian Mountains in West Virginia and North Carolina are less variable than expected and not suitable for reforestation in Canada.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 1993-10-01
    Description: An experimental and numerical investigation of the density distribution produced in a container by a negatively buoyant jet has been undertaken to evaluate the effect of the forced vertical motion of the environment. Vertical motion results from inflows and exhausts above and below the jet. Three distinct cases were identified. In the first, a velocity in the environment opposed the jet and produced a steady flow. This configuration was used to measure the entrainment flux along the length of the fountain. This configuration is similar to a jet impinging on an interface for which the entrainment depends on the local Froude number. The experiments covered a wider range of local Froude numbers than previously published and have produced results which are different from those in the literature. In the second case, the environment was at rest except for the motion induced by the fountain. An interface formed at the base of the fountain and moved quickly to the top. Once there, it advanced slowly due to entrainment through the end of the fountain and the length of the fountain increased. The final case is a co-flowing environment. No interface formed if the environment velocity was greater than the advance velocity of the end of the fountain. However, one formed for a smaller environment velocity and the end of the fountain was observed to undergo a quasi-periodic jump phenomenon. The top of the fountain would advance with the environment particles for a short time and then snap back to the elevation of a fountain in an infinite environment. A new interface formed and the cycle repeated. © 1993, Cambridge University Press. All rights reserved.
    Print ISSN: 0022-1120
    Electronic ISSN: 1469-7645
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...