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  • 1
    Electronic Resource
    Electronic Resource
    Anomalous echoes observed with the EISCAT UHF radar at 100-km altitude (1997)
    Springer
    Annales geophysicae 14 (1997), S. 1328-1342 
    Details
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We have observed a number of strong echoes with the European incoherent-scatter (EISCAT) UHF (930-MHz) radar at angles 83.5° and 78.6° with the geomagnetic field and at about 100-km altitude north in the auroral zone. The echoes are shortlived and occur in single 2- or 10-s data dumps. They are offset by 125–130 kHz with respect to the transmitted frequency. In most cases the offset compares well with the frequency of gyro lines in the incoherent-scatter spectrum, as given by the standard linear dispersion relation. But sometimes the measured offsets deviate significantly from the model calculations, and the interpretation in terms of gyro lines becomes questionable. The discrepancy could possibly be explained by local deviations in the magnetic field from the model (IGRF 1987), which are generated by incoming particle beams. A more serious problem with the gyro-line theory is how the line can be excited at altitudes where the collisional damping is substantial. The high intensity and short lifetime of the signal point to a fast-growing plasma instability as the likely excitation mechanism, if the gyro-line interpretation is correct. The cause of the instability could be the same particle beams as those causing the disturbances in the magnetic field. Alternatively, the observations may be interpreted as meteor head echoes. The large Doppler shifts, the short lifetimes and the altitudes of the signals support this explanation. The main difficulty is that the distribution of measured offsets appears to be different in magnetically active conditions and in less active conditions. Also, the occurrence of echoes does not seem to follow the expected changes in meteor density. More observations in different conditions are needed to decide between the two interpretations. As it is, we are inclined to believe in the meteor head echo theory, the objections to the gyro-line theory being more fundamental.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-996-1328-4
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  • 2
    Electronic Resource
    Electronic Resource
    The economic impact of feeding restrictions on US catfish, Ictalurus punctatus (Rafinesque), aqafuaculture operations (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 26 (1995), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Increasing stocking densities in catfish, Ictalurus punctatus (Rafinesque), aquaculture are making maintenance of water quality a crucial element of production strategy. A bioeconomic simulation model for catfish has been adapted to assess alternative feeding restriction management strategies for US catfish aquaculture operations. The current model includes five decision variables: feeding rate, diet quality, stocking weight, stocking date, and length of growing season. The growth model follows a bioenergetics approach, where the balance between energy intake and energy expenditure determines fish growth. The purpose of this analysis was to simulate changes in production practices resulting from water quality restrictions. Model simulations indicate that restricting maximum daily feeding allowance to maintain higher water quality will actually increase feed requirements to reach a harvestable fish size. In addition, as producers increasingly attempt to spread harvests throughout the year, both for their own cash flow needs and the consistent supply requirements of processors, restricting daily feed allowance will make summer harvests particularly difficult.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.1995.tb00959.x
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  • 3
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    A Study in Shirley's Comedies of London Life (1914)
    Austin : Periodicals Archive Online (PAO)
    Texas Studies in Literature and Language. 2 (1914) 
    Details
    ISSN: 0040-4691
    Topics: Linguistics and Literary Studies
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:6464-1914-002-00-000001
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  • 4
    Electronic Resource
    Electronic Resource
    Elevated serum dopamine-β-hydroxylase activity in rats with inherited diabetes insipidus (1975)
    Springer
    Journal of neural transmission 36 (1975), S. 107-112 
    Details
    ISSN: 1435-1463
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The activity of dopamine-β-hydroxylase, the enzyme that catalyzes the conversion of dopamine to norepinephrine, was measured in the serum of a strain of Wistar rats homozygous and heterozygous for a genetic form of hypothalamic diabetes insipidus and in Wistar control rats. Serum dopamine-β-hydroxylase activity and water intake was highest in the homozygous affected rats and lowest in normal controls. Treatment with pitressin tannate reduced serum enzyme activity and water intake in rats with diabetes insipidus to levels which did not differ from controls. Thus serum dopamine-β-hydroxylase activity appeared to vary directly with changes in sympathetic nerve activity in response to intravascular volume depletion and repletion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01256758
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  • 5
    Electronic Resource
    Electronic Resource
    Incorporating multi-region crack growth into mechanical reliability predictions for optical fibres (1997)
    Springer
    Journal of materials science 32 (1997), S. 5305-5311 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Most mechanical reliability models for optical fibre assume the same crack growth parameters (n and B) for both proof testing and in-service life. However, this assumption leads to inconsistencies in our understanding of how the fibre behaves in the laboratory and in the field. In 1983 Ritter et al. suggested that proof-testing and in-service crack growth parameters differ according to their respective environments. Recent high-speed strength tests of abraded optical fibres indicate that crack-growth parameters change as a function of time under the same environmental conditions. It was suggested that at high processing speeds, the presence of crack growth in Region II of the K–V relationship should be entertained. In this work, the impact of Region II crack growth during proof testing was explored and the effect on mechanical reliability predictions evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018662727060
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetic studies of the lactic acid fermentation in batch and continuous culturesPresented at 162nd National American Chemical Society meeting, Division of Microbial Chemistry and Technology, Washington, D.C., September 14, 1971. (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 14 (1972), S. 233-252 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The fermentation kinetics of the homofermentative organism Lactobacillus delbrueckii in a glucose-yeast extract medium is studied in both batch and continuous culture under conditions of controlled pH. From a graphical analysis of the batch data, a mathematical model of the process is derived which relates bacterial growth, glucose utilization, and lactic acid formation. The parameters in the model represent the activity of the organism and are a function of pH, having a maximum value at about 5.90. In a continuous stirred tank fermentor (CSTF), the effect of pH, feed concentration, and residence time is observed. The feed medium is a constant ratio of two parts glucose to one part yeast extract plus added mineral salts. An approximate prediction of the steady-state behavior of the CSTF can be made using a method based on the kinetic model derived for the batch case. In making step changes from one steady state to another, the transient response is observed. Using the kinetic model to simulate the transient period, the calculated behavior qualitatively predicts the observed response.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260140207
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  • 7
    Electronic Resource
    Electronic Resource
    A random vortex simulation of wind-flow over a building (1985)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 5 (1985), S. 849-871 
    Details
    ISSN: 0271-2091
    Keywords: Random Vortex Method ; Wind Engineering ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The random vortex method of Chorin1 provides a numerical simulation of high-Reynolds number flow in two dimensions. The method can be used to model the viscous interaction of wind with a surface-mounted obstacle of arbitrary cross-section. In this paper the method has been used to investigate the flow of wind over common building shapes; an inlet profile is chosen to represent the stationary aspects of the atmospheric boundary layer. The evolution of flow over a short time-interval after flow initialization is depicted, and a mean value of pressure coefficient, Cp, is calculated over the building perimeter. Some comparison is made with published wind-tunnel measurements for the case of a surface-mounted square-section block and for a building model with 10° roof pitch.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650051002
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  • 8
    Electronic Resource
    Electronic Resource
    A three-dimensional simulation of wind flow around buildings (1986)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 6 (1986), S. 113-127 
    Details
    ISSN: 0271-2091
    Keywords: Wind Engineering ; Control Volume Method ; Wind Flow Simulation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The steady Navier-Stokes equation is solved to simulate the wind-flow environment of three-dimensional configurations of buildings. The method assumes an incident wind described by a power-law velocity profile. A new method for controlling the two-part nested solution iteration is introduced. The simulation is compared to some published wind-tunnel measurements.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650060303
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  • 9
    Electronic Resource
    Electronic Resource
    Numerical modelling of wind flow over buildings in two dimensions (1984)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 25-41 
    Details
    ISSN: 0271-2091
    Keywords: Architectural Wind-flow ; Environmental Problems ; Random Vortex Method ; Control Volume Method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Numerical solutions to the Navier-Stokes equation may provide designers with predictions of the wind environment of buildings under design. To investigate this possibility, two complementary solution procedures are implemented for two-dimensional geometry: a random vortex method to depict the flow evolution, and a control volume method to depict the steady flow field. These are both illustrated by specific application to the case of a building form with a roof of arbitrary pitch.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650040104
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