scholarly journals Doppler Shift of Radio Signals Transmitted between Orbiting Satellites

1982 ◽  
Vol 35 (2) ◽  
pp. 155 ◽  
Author(s):  
PL Dyson ◽  
JA Bennett
Keyword(s):  
Electron Concentration ◽  
Doppler Shift ◽  
Rate Of Change ◽  
Line Of Sight ◽  
Concentration Gradients ◽  
Mean Velocity ◽  
Radio Signals ◽  
The Mean ◽  
The Moment ◽  
The Individual

A general expression, applicable at VHF and above, is derived for the Doppler shift of radio signals transmitted between two satellites embedded in the ionosphere. The Doppler shift is made up of several contributions which depend on (a) the rate of change of the free space path between the satellites, (b) the components, perpendicular to the line of sight between the satellites, of both the mean velocity of the satellites and the electron concentration gradients, (c) the moment of the perpendicular electron concentration gradients and the deviations from the mean of the individual satellite perpendicular velocities, (d) the velocity components along the line of sight between the satellites, and the electron concentration values at each satellite, and (e) changes occurring in the ionosphere with time.

The mean velocity and velocity distributions of normal bull spermatozoa at different hydrogen-ion concentrations, derived from photo-electric measurements

1960 ◽  
Vol 54 (3) ◽  
pp. 300-309 ◽  
Author(s):  
C. van Duijn ◽  
R. Rikmenspoel
Keyword(s):  
Frequency Distribution ◽  
Ph Value ◽  
Strain Effect ◽  
Anaerobic Conditions ◽  
Mean Velocity ◽  
Ph Values ◽  
The Mean ◽  
The Individual ◽  
Image Position ◽  
Ph Curve

1. The mean velocity ῡ and the velocity frequency distribution f(υ) of bull spermatozoa with normal motility have been determined in standardized eggyolk—citrate buffers at different pH values, ranging frompH 5·70 to 8·35.Under assumed approximately anaerobic conditions at37·0 ± 0·1° C. the mean velocity was found to show a straight-line relationship -with pH in the physiological region pH 5·70–7·50, according to the general equationStatistically, k was shown to be a linear function of a, namely,Consequently, the dependence of the mean velocity of the spermatozoa from any ejaculate can be characterized by the one parameter a = dῡ/dpH. (dimension μ/sec./pH), determining the slope of the ῡ υs. pH curve.The mean velocity of all individual spermatozoa (measurements of all ejaculates at the same pH value pooled together) could be described accurately by the equation:For some ejaculates the linear relationship was found to hold up to pH 8·00.2. The velocity frequency distribution curves were found to change with pH. At pH 5·70 the curves are skew with a relatively high top value. At increasing pH values both the top value and skewness decrease. The mean standard deviation of the velocity distribution f(υ) was found to be proportional to pH and could be described by the equationThis means that the variability in swimming speeds of the individual spermatozoa of any ejaculate increases proportionally with pH, indicating a strain effect of increasing alkalinity on the population, irrespective of the general stimulation of motility in the region up to pH 7·50.3. At each pH value the mean velocity decreases with time. Under assumed approximately anaerobic conditions at 37° C. the speed of velocity decrease as a function of pH was found to differ so much between different ejaculates that no generalization could be derived from the available material. The same holds for the effect of pH on the number of normally moving spermatozoa in the diluted ejaculate.4. The total number of spermatozoa moving normally depends on pH, but the optimum varies with the individual ejaculates.

scholarly journals On The Approximation of the Total Amount of Claims

1977 ◽  
Vol 9 (3) ◽  
pp. 281-289 ◽  
Author(s):  
T. Pentikäinen
Keyword(s):  
Distribution Function ◽  
Standard Deviation ◽  
Normal Approximation ◽  
Mean Value ◽  
Normal Distribution Function ◽  
Acceptable Accuracy ◽  
The Mean ◽  
The Moment ◽  
The Individual ◽  
Image Position

Several “short cut” methods exist to approximate the total amount of claims ( = χ) of an insurance collective. The classical one is the normal approximationwhere and σx are the mean value and standard deviation of x. Φ is the normal distribution function.It is well-known that the normal approximation gives acceptable accuracy only when the volume of risk business is fairly large and the distribution of the amounts of the individual claims is not “too dangerous”, i.e. not too heterogeneous (cf. fig. 2).One way to improve the normal approximation is the so called NP-method, which provides for the standardized variable a correction Δzwhereis the skewness of the distribution F(χ). Another variant (NP3) of the NP-method also makes use of the moment μ4, but, in the following, we limit our discussion mainly to the variant (2) (= NP2).If Δz is small, a simpler formulais available (cf. fig. 2).Another approximation was introduced by Bohman and Esscher (1963). It is based on the incomplete gamma functionwhere Experiments have been made with both formulae (2) and (4); they have been applied to various F functions, from which the exact (or at least controlled) values are otherwise known. It has been proved that the accuracy is satisfactory provided that the distribution F is not very “dangerous”.

scholarly journals The transport of vorticity and heat through fluids in turbulent motion

1932 ◽  
Vol 135 (828) ◽  
pp. 685-702 ◽  
Keyword(s):  
Horizontal Plane ◽  
Vertical Axis ◽  
Rate Of Change ◽  
Mean Flow ◽  
Mean Velocity ◽  
Mean Values ◽  
Plane Element ◽  
The Mean ◽  
Coefficient Of Viscosity ◽  
Change In Mean

In Reynolds’ well-known theory of turbulent flow the effect of turbulence on the mean flow of a fluid is conceived as the same as that of a system of stresses which, like those due to viscosity, may have tangential as well as normal components across any plane element. Taking the case of laminar mean flow, that is when the mean flow is, say, horizontal and constant in direction and magnitude at any given height, the components of stress over a horizontal plane at height z are F x and F y where F x = — ρ uw — , F y = — ρ vw — , and u , v , w are the components of turbulent velocity parallel to two horizontal axes x and y and the vertical axis z . The bar denotes that mean values have been taken over a large horizontal area and ρ is the density of the fluid. The stress F x , is therefore due to the existence of a correlation between u and w. In the extension of Reynolds’ theory due to Prandtl this correlation depends on the rate of change in mean velocity. In its most simplified form the theory may be expressed as follows. A portion of fluid possessing the mean velocity of a level z 0 may be conceived to move upwards to a layer of height z 0 + l preserving the mean velocity U 0 of the layer from which it originated. At this height it is conceived to mix with its surroundings. If l is small the mean velocity of this layer is U 0 + l d U/ dz , U being the mean velocity at height z , so that u = — l d U/ dz , and hence F x = ρ wl — d U/ dz . The quantity ρ wl — is therefore of the same dimensions as viscosity and in Prandtl’s theory it is treated as though it were in fact a coefficient of viscosity, though not necessarily as one which has the same value at all points in the field.

Exploring linguistic malleability across the life span: Age-specific patterns in quotative use

2015 ◽  
Vol 44 (4) ◽  
pp. 457-496 ◽  
Author(s):  
Isabelle Buchstaller
Keyword(s):  
Life Span ◽  
Language Ideologies ◽  
Rapid Change ◽  
Rate Of Change ◽  
Small Scale ◽  
Low Frequencies ◽  
Trend Data ◽  
Age Grading ◽  
The Moment ◽  
The Individual

AbstractThis article explores the degree and kind of lability that occurs throughout the life span of the individual during ongoing rapid change in the quotative system. Two comparative analyses trace speakers' use ofbe likeacross a shorter and a longer time span. Trend data reveal that the robust change is arrested in the middle age brackets; speakers in their thirties seem to display ‘retrograde movement’ (Sankoff & Wagner 2006) away from the community-wide change. This finding could be interpreted as incipient age-grading. A small-scale panel sample collected forty-two years after the initial interview suggests that some older speakers participate in the trend, albeit at very low frequencies. This finding, while exploratory at the moment, might be interpreted as indicative of ‘life-span change’ (Sankoff 2005). A conception of the change in progress in the quotative system as monotonous would thus both under and overestimate the rate of change. (Change across the life span, age-grading, retrograde change, life-span change, quotation, style, language ideologies)*

Molecular Theory of Energy Conversion and of Initiation of Chemical Reactions in Solids

1971 ◽  
Vol 49 (9) ◽  
pp. 1407-1412
Author(s):  
Charles E. Melton
Keyword(s):  
Energy Conversion ◽  
Chemical Reactions ◽  
Present Model ◽  
Nearest Neighbor ◽  
Vibrational Energy ◽  
Vibrational Excitation ◽  
Hard Sphere Model ◽  
Mean Velocity ◽  
The Mean ◽  
The Individual

A theory has been developed to describe the initiation of chemical reactions in solids. Two basic assumptions are made to formulate the model. First, the initiation of chemical reactions in solids ultimately results from the vibrational excitation of the individual molecules in the solid, and second, the lattice vibrations in a solid can be treated as pseudocollisions between the individual molecules in the lattice. In effect, the solid is treated as an ordered dense gas. These assumptions permit us to describe chemical reactions in a solid within the framework of collision theory. The resultant rate constant, k, depends on molecular and lattice parameters and on the temperature. It is of the form [Formula: see text], where N is the number of nearest neighbor molecules, b is the lattice spacing, v is the mean velocity of the individual molecules, and [Formula: see text]is the probability of translational–vibrational energy conversion.Conclusions based on the present model are in accord with qualitative results from a hard sphere model. For example, energy conversion (translational to vibrational) is many orders of magnitude greater in the region of a defect. Consequently, the probability for initiation of chemical reactions is orders of magnitude greater in the region of a defect.

scholarly journals Analysis of operating parameters of the aircraft piston engine in real operating conditions

2021 ◽  
Author(s):  
Jacek Czarnigowski ◽  
Daniel Rękas ◽  
Karol Ścisłowski ◽  
Michał Trendak ◽  
Krzysztof Skiba
Keyword(s):  
Rate Of Change ◽  
Operating Conditions ◽  
Air Pressure ◽  
Operational Parameters ◽  
Piston Engine ◽  
Mean Values ◽  
The Mean ◽  
The Individual ◽  
Operating Points ◽  
Head Temperature

The article presents the results of analysis of operational parameters of piston engine CA 912 ULT which is a propulsion system of ultralight gyroplane Tercel produced by Aviation Artur Trendak. Research was conducted under normal operating conditions of the autogyro and data was collected from 20 independent tests including a total of 28 flight hours, divided into training flights and competition flights.Engine speed, manifold air pressure and temperature, fuel pressure, injection time, and head temperature were recorded at 9 Hz during each flight. Collective results were presented to show the statistical analyses of the individual parameters by determining the mean values, standard deviations and histograms of the distribution of these parameters. Histograms of operating points defined by both engine speed and manifold air pressure were also determined. Analyses of the engine dynamics as a distribution of the rate of change of the engine rotational speed were also carried out. It was shown that the engine operating points are concentrated mainly in the range of idle and power above 50% of nominal power. The most frequent range is 70-80% of nominal power. It was also shown that the dynamics of engine work in real operating conditions is small. It was also shown that the way of use significantly influences the distribution of operating points. During training flights, an increase in the number of take-offs and landings causes an increase in the amount of engine work at take-off and nominal power and at idle.

scholarly journals Observation of Five-Minute-Period Gravity Waves in the Solar Photosphere

1983 ◽  
Vol 66 ◽  
pp. 163-164
Author(s):  
R.T. Stebbins ◽  
Philip R. Goode ◽  
Henry A. Hill
Keyword(s):  
Gravity Waves ◽  
Traveling Waves ◽  
Doppler Shift ◽  
Detailed Examination ◽  
Acoustic Mode ◽  
Solar Photosphere ◽  
Mean Velocity ◽  
Velocity Amplitude ◽  
Minute Period ◽  
The Mean

AbstractVertically propagating traveling waves have been observed in the solar photosphere. These waves have a period of 278 ± 41 seconds and a vertical phase velocity of about 2 km s-1. It is noted that these waves also have approximately the same period as the well-studied five-minute-period acoustic mode, which is evanescent in the photosphere. The only consistent interpretation of the traveling waves implies that they are gravity waves. About half the time the gravity waves are outgoing, while the remainder of the time they are ingoing.The data were collected by Stebbins et al. (1980) to study the vertical structure of the photosphere. They examined velocity pertubations at nine altitudes in the photosphere using a Doppler shift technique. The current work represents a reanalysis of that data which uncovered the five-minute-period traveling waves.The mean velocity amplitude of disturbances at a given altitude, as registered in the observed Doppler shift, was found to be directly proportional to the mean velocity amplitude at the base of the photosphere. This was the expected relationship between the velocity amplitudes. It was not expected that the standard deviation of the velocity amplitude at a particular altitude would be independent of the velocity amplitude at the base of the photosphere. In addition, the phase difference between velocities at different altitudes is, unexpectedly, inversely proportional to the velocity amplitude at any altitude. These two traits of the data are consistent with a five-minute-period nonacoustic traveling wave being superimposed on the five-minute-period acoustic mode. This supposition is borne out by a detailed examination of the data in the complex plane of amplitude and phase and by a calculation of the power spectrum of the traveling waves as a function of their vertical wavenumber (see Hill et al., 1982).

Influence of Grip Width and Anthropometric Characteristics on the Bench-Press Load–Velocity Relationship

2020 ◽  
Vol 15 (7) ◽  
pp. 949-957
Author(s):  
Alejandro Pérez-Castilla ◽  
Daniel Jerez-Mayorga ◽  
Dario Martínez-García ◽  
Ángela Rodríguez-Perea ◽  
Luis J. Chirosa-Ríos ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Regression Models ◽  
Bench Press ◽  
Linear Regression Models ◽  
Mean Velocity ◽  
Movement Velocity ◽  
Anthropometric Characteristics ◽  
The Mean ◽  
The Individual

Purpose: To compare the load–velocity (L-V) relationship between bench-press exercises performed using 4 different grip widths, to determine the association between the anthropometric characteristics and L-V profile, and to explore whether a multiple linear-regression model with movement velocity and subjects’ anthropometric characteristics as predictor variables could increase the goodness of fit of the individualized L-V relationship. Methods: The individual L-V relationship of 20 men was evaluated by means of an incremental loading test during the bench-press exercise performed on a Smith machine using narrow, medium, wide, and self-selected grip widths. Simple and multiple linear-regression models were performed. Results: The mean velocity associated with each relative load did not differ among the 4 grip widths (P ≥ .130). Only body height and total arm length were correlated with the mean velocity associated with light and medium loads (r ≥ .464). A slightly higher variance of the velocity attained at each relative load was explained when some anthropometric characteristics were used as predictor variables along with the movement velocity (r2 = .969 [.965–.973]) in comparison with the movement velocity alone (r2 = .966 [.955–.968]). However, the amount of variance explained by the individual L-V relationships was always higher than with the multiple linear-regression models (r2 = .995 [.985–1.000]). Conclusions: These results indicate that the individual determination of the L-V relationship using a self-selected grip width could be recommended to monitor relative loads in the Smith machine bench-press exercise.

A Simple Method for the Evaluation of Internal Doses in Nuclear Medicine

1974 ◽  
Vol 13 (02) ◽  
pp. 193-206
Author(s):  
L. Conte ◽  
L. Mombelli ◽  
A. Vanoli
Keyword(s):  
Nuclear Medicine ◽  
Close Agreement ◽  
Whole Body ◽  
Simple Method ◽  
Rapid Estimation ◽  
Absorbed Doses ◽  
The Mean ◽  
The Individual ◽  
Estimation Of Risk

SummaryWe have put forward a method to be used in the field of nuclear medicine, for calculating internally absorbed doses in patients. The simplicity and flexibility of this method allow one to make a rapid estimation of risk both to the individual and to the population. In order to calculate the absorbed doses we based our procedure on the concept of the mean absorbed fraction, taking into account anatomical and functional variability which is highly important in the calculation of internal doses in children. With this aim in mind we prepared tables which take into consideration anatomical differences and which permit the calculation of the mean absorbed doses in the whole body, in the organs accumulating radioactivity, in the gonads and in the marrow; all this for those radionuclides most widely used in nuclear medicine. By comparing our results with dose obtained from the use of M.I.R.D.'s method it can be seen that when the errors inherent in these types of calculation are taken into account, the results of both methods are in close agreement.

SERUM THYROTROPHIN AND THE RESPONSE TO THYROTROPHIN RELEASING HORMONE IN SYMPTOMLESS AUTOIMMUNE THYROIDITIS AND IN BORDERLINE AND OVERT HYPOTHYROIDISM

1974 ◽  
Vol 75 (2) ◽  
pp. 274-285 ◽  
Author(s):  
A. Gordin ◽  
P. Saarinen ◽  
R. Pelkonen ◽  
B.-A. Lamberg
Keyword(s):  
Autoimmune Thyroiditis ◽  
Elevated Serum ◽  
Mean Value ◽  
Primary Hypothyroidism ◽  
Overt Hypothyroidism ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
The Mean ◽  
The Individual ◽  
Serum Tsh

ABSTRACT Serum thyrotrophin (TSH) was determined by the double-antibody radioimmunoassay in 58 patients with primary hypothyroidism and was found to be elevated in all but 2 patients, one of whom had overt and one clinically borderline hypothyroidism. Six (29%) out of 21 subjects with symptomless autoimmune thyroiditis (SAT) had an elevated serum TSH level. There was little correlation between the severity of the disease and the serum TSH values in individual cases. However, the mean serum TSH value in overt hypothyroidism (93.4 μU/ml) was significantly higher than the mean value both in clinically borderline hypothyroidism (34.4 μU/ml) and in SAT (8.8 μU/ml). The response to the thyrotrophin-releasing hormone (TRH) was increased in all 39 patients with overt or borderline hypothyroidism and in 9 (43 %) of the 21 subjects with SAT. The individual TRH response in these two groups showed a marked overlap, but the mean response was significantly higher in overt (149.5 μU/ml) or clinically borderline hypothyroidism (99.9 μU/ml) than in SAT (35.3 μU/ml). Thus a normal basal TSH level in connection with a normal response to TRH excludes primary hypothyroidism, but nevertheless not all patients with elevated TSH values or increased responses to TRH are clinically hypothyroid.

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