scholarly journals Asteroid Masses and Densities

1971 ◽  
Vol 12 ◽  
pp. 33-39 ◽  
Author(s):  
Joachim Schubart
Keyword(s):  
Total Mass ◽  
Direct Determination ◽  
Absolute Magnitude ◽  
Strong Increase ◽  
Minor Planets ◽  
Solar Mass ◽  
A Value ◽  
The Mean ◽  
The Masses

Before 1966, when Hertz (1966) published his first direct determination of the mass of Vesta, all our knowledge on asteroid masses was based on estimates. The masses of the first four minor planets resulted from the measured diameters by Barnard (1900) (see the paper by Dollfus in this volume) and from estimated mean densities. The diameters of the smaller objects were derived from their brightness and an estimate of their reflectivity (usually the reflectivity of the Moon was adopted). In 1901, Bauschinger and Neugebauer (1901) derived a value for the total mass of the first 458 asteroids. All the diameters were computed from the brightness with an assumed value for the reflectivity. The diameter of Ceres found in this way is very close to Barnard’s (1900) value. The mean density of the 458 asteroids was put equal to that of Earth, and their total mass resulted as 3 X 10-9 solar mass. Stracke (1942) used the same method with an increased material, but the addition of more than 1000 faint asteroids did not bring a significant change in the estimate of the total mass. The report on the McDonald asteroid survey (Kuiper et al., 1958) does not contain another estimate of the total mass of the asteroid ring, but it points to the possibility of a very rapid increase in the number of asteroids with decreasing absolute brightness. If this increase is strong enough, each interval of 1 mag in absolute magnitude can contribute the same amount to the total mass. In the range of magnitudes covered by the Palomar-Leiden survey (PLS) (van Houten et al., 1970), there are no indications for such a strong increase.

scholarly journals The Parallaxes of U Gem Variables

1979 ◽  
Vol 53 ◽  
pp. 494-494
Author(s):  
Karl W. Kamper
Keyword(s):  
Confidence Level ◽  
Absolute Magnitude ◽  
Weighted Mean ◽  
Quiescent Phase ◽  
A Value ◽  
The Mean ◽  
The Absolute ◽  
Absolute Magnitudes

An Allegheny parallax series of SS Cyg, consisting of 52 exposures obtained on 15 nights, was recently measured on the PDS microphotometer at the David Dunlap Observatory, and a value of (m.e.) derived for the absolute parallax. This is close to the mean of the two previous discordant measures for this star given in the table below. The weighted mean of the three determinations implies that the absolute magnitude, at quiescent phase, of the star is between 7.0 and 9.0 formally at a 90% confidence level. Recent parallax determinations made at Lick by Vasilevskls et al. (1975) for three other stars, listed below along with the Mt. Wilson value for U Gem, imply even fainter absolute magnitudes.

Regulatory Agency Acceptance of the Interpretation of the Freezing Point Value of Milk as Part of the Official Thermistor Cryoscopic Method

1970 ◽  
Vol 53 (3) ◽  
pp. 539-542
Author(s):  
R W Henningson
Keyword(s):  
Milk Sample ◽  
North American ◽  
Freezing Point ◽  
Sample Survey ◽  
Regulatory Agencies ◽  
A Value ◽  
Added Water ◽  
The Mean ◽  
Definition Of

Abstract A 1968 North American authentic milk sample survey determined that the mean freezing point value of milk is –0.5404°C. Statistical concepts permit the calculation of a value, –0.525°C, 2.326 standard deviations from a mean with 95% confidence that 99% of all subsequent observations will be below the value. Based on this survey, it was recommended that the Interpretation of the freezing point value of milk be made a part of the official final action thermistor cryoscopic method for the determination of the freezing point value of milk, and include the following: an upper limit for the freezing point value of milk, an official definition of an authentic milk sample, and a logical procedure for the confirmation of added water. A copy of the report and an explanatory letter were sent to approximately 100 North American regulatory agencies. Reports were received from 49 regulatory agencies with 39 favoring the recommendations, 6 opposing the recommendations, and 4 having no opinion. It is recommended that the Interpretation of the freezing point of milk be included in both the thermistor cryoscopic and the Hortvet methods.

scholarly journals The Planetary Masses and the Orbits of the First Four Minor Planets

1971 ◽  
Vol 9 ◽  
pp. 246-249
Author(s):  
J. Schubart
Keyword(s):  
Minor Planets ◽  
Numerical Tests ◽  
The Masses

AbstractNumerical tests are the basis of a study about the effects caused in the orbits of the planets (l)-(4) by possible errors in the system of planetary masses. The masses of five major and three minor planets are considered. Especially, the effects caused by (1) Ceres in the orbit of (2) Pallas since the time of discovery are found to be large enough for a determination of the mass of Ceres. A first result for this mass is (6.7 ±0.4) x 10-10 solar masses.

A Rapid Method of Determining Ammonium in Water With a Univalent Cation Glass Electrode

1971 ◽  
Vol 28 (5) ◽  
pp. 759-764 ◽  
Author(s):  
Jan Barica
Keyword(s):  
Rapid Method ◽  
Direct Determination ◽  
Glass Electrode ◽  
Ammonium Ion ◽  
Mean Error ◽  
Univalent Cation ◽  
The Mean

The use of a univalent cation glass electrode for determining ammonium in water is described. The method enables direct determination of ammonium ion in concentrations above 0.5 mg/liter without any dilution or pretreatment of sample. A constant background of Na+ and K+ in samples is required, with concentration of potassium being lower than that of ammonium. For several types of natural and enriched waters with ammonium content up to 40 mg/liter NH4-N, the mean error by the method was ±4.9%.

Determination of the masses of Jupiter and Saturn from the motion of Trojans

1974 ◽  
Vol 22 ◽  
pp. 93-96
Author(s):  
H. Scholl
Keyword(s):  
Minor Planets ◽  
Planetary Mass ◽  
Orbital Periods ◽  
The Masses ◽  
Two Bodies

The mass of a planet can be determined by the motion of its satellites or by perturbational effects on nearby bodies, such as comets, planets, minor planets. It is well known, for instance, that a body on a nearby orbit which is in close resonance with a planet is suitable for the determination of the planetary mass. In this case the orbital periods of the two bodies are equal or nearly equal to the ratio of small integers (i.e. 1: 1, 2: 1, 3:2).

UNTERSUCHUNGEN ÜBER DIE TETRAHYDROALDOSTERON AUSSCHEIDUNG IM KINDESALTER DURCH GASCHROMATOGRAPHIE MIT ELEKTRONENEINFANGDETEKTOR (ECD)

1972 ◽  
Vol 70 (3) ◽  
pp. 533-551 ◽  
Author(s):  
J. Solc ◽  
D. Knorr
Keyword(s):  
Sodium Intake ◽  
Active Phase ◽  
Strong Increase ◽  
Gas Liquid Chromatography ◽  
Aldosterone Secretion ◽  
Infancy And Childhood ◽  
The Mean ◽  
Potassium Loading ◽  
Very High

ABSTRACT Tetrahydroaldosterone-(THAldo)-glucuronide is the most important metabolite of aldosterone in the urine. According to Nicolis & Gabrilove (1969) we developed a GLC method for the determination of THAldo. The method includes the following steps: Enzymatic hydrolysis, extraction with ethylacetate, formation of γ-lactone, first TLC, formation of heptafluorobutyrate (HFB), second TLC, gas liquid chromatography (GLC) with electron capture detector (ECD), correction for losses by the internal 3H-THAldo standard. As little as 3 ng/sample can be detected with a coefficient of variation of < 10%. The paper presents more than 300 THAldo determinations during infancy and childhood. At the age of 5–30 days there is a significant (P < 0.01) peak of the THAldo excretion. The biological meaning of these high THAldo values in the early days of life is not clear at the present time. The peak is independent of the nutrition. After the age of 12 months the mean THAldo excretion is about 30 μg/m2/d. There is a circadian rhythm with a peak in the late morning. The dependence of the THAldo excretion on the sodium intake in childhood is the same as in adults. After potassium loading there is likewise a strong increase in the THAldo excretion. In a child suffering from Addison's disease we found about 30% of the substituted aldosterone as THAldo-glucuronide in the urine. As well angiotensin as ACTH induce an increase of the THAldo excretion. After dexamethasone there is a decrease of THAldo excretion indicating again an ACTH dependence of the aldosterone secretion. Children suffering from nephrotic syndrome during the active phase of the disease show very high values of THAldo in the urine. Under treatment with corticosteroids the THAldo excretion decreases depending on the remission. Treatment with both furosemide and potassium induces again a sharp increase of the THAldo excretion.

scholarly journals 34. Meteor mass distribution from underdense-trail echoes

1968 ◽  
Vol 33 ◽  
pp. 362-372 ◽  
Author(s):  
M. Šimek ◽  
B.A. McIntosh
Keyword(s):  
High Power ◽  
Statistical Error ◽  
Total Sample ◽  
Logarithmic Scale ◽  
Line Density ◽  
A Value ◽  
Electron Line ◽  
The Mean ◽  
Image Position

The amplitude of meteor echoes is recorded on a logarithmic scale by a high-power radar equipment (λ = 9·2 m, PT=3 MW, G = 5·6) at Springhill Meteor Observatory near Ottawa. The smallest amplitude measured corresponds to a pulse power of 10−12 W, which represents a minimum electron line density of about 7 × 1011 el/m or a radio magnitude of + 10.Distribution curves of number of echoes as a function of echo power have been obtained from some 50 samples of 500 meteors each, at various times of day on about 1 day per month. The slopes showed little variation throughout the year. The statistical error in the slope value for any one sample was small, ~ 2–3%. However, determination of the mass index s from these slopes involves several problems. On the basis of simplest theory we have obtained for the sporadic background, with no definite seasonal or diurnal variation.During shower periods, lower values of s were obtained. For the 1966 Leonids, s for the shower was determined by estimating the percentage of shower meteors in the total sample. A value s = 1·7 ± 0·1 was obtained as the mean of 6 samples. It is not known to what extent the height-ceiling effect influences the observation of this shower.

A method for the direct determination of the rate constants for radical-radical interactions in the gas phase II. The rate constant for the recombination of methyl radicals

1957 ◽  
Vol 243 (1232) ◽  
pp. 130-142 ◽  
Keyword(s):  
Gas Phase ◽  
Rate Constant ◽  
Room Temperature ◽  
Direct Determination ◽  
Theoretical Interpretation ◽  
Methyl Radicals ◽  
Gas Phase Reactions ◽  
A Value ◽  
Acetone Vapour

The technique outlined in part I of this paper has been employed to study the photo­sensitized decomposition of acetone vapour. A theoretical interpretation of the non-stationary state applied to non-chain photochemical gas phase reactions with second-order termination has been given and the effects of non-homogeneous absorption of radiation have been considered. A value has been obtained for the rate constant for the recombination of methyl radicals in the gas phase at room temperature.

scholarly journals Application of ion pair complexes to design novel potentiometric membrane sensors for direct determination of frusemide in pharmaceuticals

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah
Keyword(s):  
Limit Of Detection ◽  
Direct Determination ◽  
Standard Addition ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Bromophenol Blue ◽  
Experimental Parameters ◽  
The Mean

Abstract Background Fabrication of two membrane sensors using two acidic indicators among sulphonthalein dyes, namely bromophenol blue (BPB) and bromocresol green (BCG), and their use as indicative electrodes for the quantification of frusemide (FUR) is presented. The ion pair complexes of FUR with BPB or BCG are used to prepare the membranes in THF solvent, PVC matrix and dibutyl phthalate (DBP) as plasticizer and subsequently to fabricate FUR-BPB (Sensor I) and FUR-BCG (Sensor II) sensors. Results Sensors I and II are employable to determine 2.4 × 10-5–2.4 × 10-3 mol/L FUR at operative pH of 3.71. The calibration curve between the potentials against the concentration of FUR yielded the slopes of 58.73 ± 1 and 57.66 ± 1 mV/decade, respectively, using Sensors I and II, and this confirmed the Nernstian behaviour. Satisfactory correlation was obtained between the measured potentials and FUR concentration with the proposed sensors, and this was revealed by regression coefficient values of 0.9987 and 0.9980 for Sensors I and II, respectively. The LOD (limit of detection) values were calculated and reported for both the sensors. The experimental parameters were optimised to yield acceptable characteristics of both the sensors in the context of performance. The role of excipients of tablets and interferences were assessed by standard addition protocol. The obtained results confirmed the ineffective role of excipients of tablets and foreign species used as interferents. Conclusion The designed sensors were validated to confirm the accurate, precise, robust and rugged functioning in determining FUR. The mean of recovered FUR, close to 100%, revealed the acceptable and effective functioning of the proposed sensors. Excellent results were obtained by FUR tablets’ analysis using both the sensors.

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