DETERMINATION OF AN ABSOLUTE SCALE OF CAPACITANCE

1964 ◽  
Vol 42 (1) ◽  
pp. 53-69 ◽  
Author(s):  
A. F. Dunn
Keyword(s):  
Research Council ◽  
National Research Council ◽  
The Past ◽  
Absolute Scale ◽  
Measuring Techniques ◽  
The Absolute ◽  
Better Than

In the past decade or two, the measurement of capacitance has become of much greater importance in many fields of scientific and technological investigation as well as forming the basis of many production applications. The capabilities of the capacitance measuring techniques available are of great importance, and the measurement and maintenance of an absolute scale of capacitance has become of prime importance. In the National Research Council of Canada, the absolute unit of capacitance is now known with an accuracy better than ±0.0005%, with the capability of scaling the unit of capacitance over six decades of capacitance both above and below 1 pf (1 × 10−12 f) without introducing an additional indeterminacy any greater than ±0.0005% or ±0.3 af (af = attofarad = 10−18 f).

Accuracy of the Mekometer Scale

1984 ◽  
Vol 38 (1) ◽  
pp. 27-33 ◽  
Author(s):  
D. Meier ◽  
J. M. Rüeger
Keyword(s):  
Absolute Scale ◽  
Measuring Techniques ◽  
The Absolute

The results of recent investigations into the absolute scale of Mekometer measurements and frequency measuring techniques are summarized. On this basis a revised procedure is proposed for the reduction of Mekometer distances.

Silicon-Crystal Determination of the Absolute Scale of X-Ray Wavelengths

1964 ◽  
Vol 135 (4A) ◽  
pp. A890-A898 ◽  
Author(s):  
Ivars Henins ◽  
J. A. Bearden
Keyword(s):  
Silicon Crystal ◽  
X Ray ◽  
Absolute Scale ◽  
The Absolute

ICAS Specification for Aerial Photography: A Look at their Influence on Manufacturers, Contractors and Users

1983 ◽  
Vol 37 (3) ◽  
pp. 145-155
Author(s):  
E. A. Fleming
Keyword(s):  
Aerial Photography ◽  
Research Council ◽  
National Research Council ◽  
Aerial Survey ◽  
Small Scale ◽  
Topographic Mapping ◽  
Technical Standards ◽  
The Past ◽  
Extensive Research Program ◽  
Air Photo

Aerial photography specifications for small-scale mapping in Canada have been in a process of evolution since they were first issued in 1950. An extensive research program carried out by the National Research Council has determined many of the technical standards that are in use today and the ICAS Specification for Aerial Survey Photography governs all federal photography contracted for by the Interdepartmental Committee on Air Surveys and destined for inclusion in the National Air Photo Library. The latest revision of the Specification has given them wider application by providing for the use of a greater variety of camera focal lengths and filters than are normally considered in topographic mapping. A Manual of Procedures has also been compiled which consolidates the operationally useful information for the production of photography to meet the specifications. To determine the effectiveness of the Specification an analysis of the inspection records for the past five years of small-scale photography contracted under the specifications was made. It was found that those photographic items that are essential to the photogrammetrist (lack of y-parallax, overlap) are very well controlled by this method of defining and enforcing requirements, but other important items which affect but do not noticeably impede the work of the photogrammetrist (errors in exposure and processing) have not been effectively controlled. Other methods should be investigated for achieving improvements in the future.

scholarly journals The γ-rays of radium (B + C) and of thorium (C + C')

1934 ◽  
Vol 143 (849) ◽  
pp. 350-357 ◽  
Keyword(s):  
Long Range ◽  
Published Data ◽  
Level System ◽  
The Past ◽  
Rigorous Test ◽  
Γ Rays ◽  
The Absolute ◽  
Relative Measurements ◽  
Α Particles

Reliable information about the γ-rays emitted by radium C' is particularly valuable since the main features of the nuclear level system are shown by the groups of long range α-particles and are hence accessible to direct investigation. These long range groups of α-particles have been measured recently by Rutherford, Lewis and Bowden by a greatly improved method which has not only brought to light several new groups, but in addition has given considerably greater accuracy in the determination of the energies of the groups than had been possible in the past. The energy of these groups in excess of that of the normal group is a measure of the excitation energy of the nucleus and the older measurements had indicated, as was to be expected, a close correspondence between these energies and the quantum energies of the γ-rays. The recent more accurate measurements of Rutherford, Lewis and Bowden provided the opportunity of a more rigorous test of this connection and showed the possibility, by the combination of the information from these two sources, of a direct experimental determination of the level system. However, the accuracy of the published data on the Ra C γ-rays deduced from the natural β-ray spectrum was subject to some doubts for the following reasons. The measurements dated from 1924 when the absolute energies of certain strong groups in the β-ray spectrum were measured and the energies of the remaining lines determined by relative measurements. The strong groups in question lay between 0.4 X 10 5 and 3.0 X 10 5 volts and the procedure of step-wise comparision up to energies of over 2 X 10 6 volts may have led to cumulative errors. More serious was that recent measurements on the Th (B + C) β-ray spectrum had thrown doubt on the correctness of the absolute values. Lastly, experiment gives values for H ρ , that is the momenta of the electrons in the groups, and the calculation of the energies involves e / m . The older data had been based on e / m = 1.769 X 10 7 , and while the change to the value 1.760 X 10 7 alters the energies proportionally far less, there was involved here an avoidable error which had to be removed.

The ‘mirror of evidence’ and the plausibility of judicial proof

2016 ◽  
Vol 21 (1-2) ◽  
pp. 119-132
Author(s):  
Baosheng Zhang ◽  
Jia Cao
Keyword(s):  
Proof Theory ◽  
Probabilistic Reasoning ◽  
Traditional Theory ◽  
The Past ◽  
Judicial Practice ◽  
Absolute Certainty ◽  
Direct Knowledge ◽  
Chinese Scholars ◽  
Better Than

In the process of judicial proof, the court has to make findings of fact concerning events that happened in the past. But the triers of fact have no direct knowledge of the past events. Therefore, the triers can only find the truth by means of the ‘mirror of evidence’, which inevitably differs from the original facts of the case. It is the truth reconstructed in the trier’s mind, and only a product of thought. The ‘mirror of evidence’ doctrine explains that what the fact-finder could find is only a plausible account of the truth. As the evidence-based information cannot be entirely achieved, the facts reconstructed under the ‘mirror of evidence’ doctrine seem like ‘flowers in a mirror’. The judicial proof process is mostly deemed to be a probabilistic reasoning process. But its deepest foundation is the plausibility approach. The plausibility approach properly explains judicial proof better than the probability explanation. Compared with the western countries’ undergoing evolvement of the judicial proof theory from probability to plausibility, Chinese scholars are fighting against the statutory determination of evidence doctrine. The research on probability and plausibility will provide significant enlightenment in China in terms of rejecting the traditional theory of pursuing absolute certainty in judicial proof. We hope that by progressively renewing the understanding of judicial proof, the plausibility of judicial proof can be recognised and applied gradually in the judicial practice in China.

Thermo-electricity at low temperatures III. The absolute scale of thermo-electric power: a critical discussion of the present scale at low temperatures and preliminary measurements towards its redetermination

1955 ◽  
Vol 231 (1187) ◽  
pp. 534-544 ◽  
Keyword(s):  
Electric Power ◽  
Low Temperatures ◽  
Alkali Metals ◽  
Present Theory ◽  
Critical Discussion ◽  
Electric Force ◽  
Thermo Electric ◽  
Absolute Scale ◽  
The Absolute

In order to compare exactly the present theory of thermo-electric power in metals with the behaviour of the simple alkali metals, particularly sodium, at low temperatures, it is necessary to know the absolute thermo-electric, power of one single conductor. There has been only one such determination of an absolute scale of thermo-electric power, and this was derived 23 years ago as the outcome of measurements which had been made primarily for other purposes. As measurements of the thermo-electric force of the alkali metals at low temperatures have recently become available, it is appropriate now to review critically the experimental basis of that scale. In view of new experimental evidence on the behaviour of the thermo-electric power of superconductors just above the transition point which has appeared in the last few years, it appears that a redetermination of the scale is necessary, at least at low temperatures. In this paper the present absolute scale of thermo-electric force is critically discussed particularly in relation to preliminary measurements towards its redetermination.

ABSOLUTE STANDARDIZATION OF RADIOACTIVE NEUTRON SOURCES: I. ACTIVATION OF MANGANESE BATH

1959 ◽  
Vol 37 (3) ◽  
pp. 256-262 ◽  
Author(s):  
K. W. Geiger ◽  
G. N. Whyte
Keyword(s):  
Research Council ◽  
Emission Rate ◽  
Neutron Emission ◽  
International Comparisons ◽  
National Research Council ◽  
National Bureau ◽  
Neutron Sources ◽  
Manganese Bath ◽  
Absolute Standardization

The neutron emission rate of a Ra-α-Be source of the National Research Council has been measured by moderating the neutrons in manganese sulphate solution surrounding the source. Some of the thermal neutrons captured in the bath produce manganese-56, and the neutron emission rate is found from an absolute determination of the resulting activity. A number of corrections are discussed in detail. The value of (3.22 ± 0.05) × 106 neutrons per second found for the neutron emission rate shows satisfactory agreement with the results of our intercomparison with the primary neutron standard of the National Bureau of Standards, and allows a tie-in with a series of international comparisons of primary neutron sources.

scholarly journals The Determination of Absolute Phase of a Long Baseline Interferometer and its Application to the Precise Measurement of the Constant of Nutation

1980 ◽  
Vol 78 ◽  
pp. 129-138
Author(s):  
W. H. Cannon ◽  
J. L. Yen
Keyword(s):  
Research Council ◽  
Precise Measurement ◽  
National Research Council ◽  
New Technique ◽  
Canadian Universities ◽  
Long Baseline ◽  
Absolute Phase

Long Baseline Interferometry (L.B.I.) refers to a dramatic technical breakthrough in astronomy accomplished almost exactly ten years ago in the spring of 1967 by a group of workers at the National Research Council of Canada and some major Canadian Universities. The Canadian effort was duplicated within a month by an independent American effort and it was realized soon afterward that the new technique of L.B.I. held enormous potential for geodynamical as well as astronomical studies.

Status of Salmonella – Ten Years Later

1980 ◽  
Vol 43 (4) ◽  
pp. 307-313 ◽  
Author(s):  
JOHN H. SILLIKER
Keyword(s):  
Research Council ◽  
National Research Council ◽  
Current Status ◽  
Animal Origin ◽  
Consumer Education ◽  
The Past ◽  
Human Salmonellosis ◽  
Term Basis ◽  
Handling Practices ◽  
Food Handling Practices

The current status of the Salmonella problem, 10 years after publication of the report of the Committee on Salmonella of the National Research Council, was reviewed. The incidence of human salmonellosis has increased during this period. The major source of the Salmonella problem in man still derives from foods of animal origin, especially poultry, beef and pork. Contaminated products cause disease as the result of inadequate cooking or cross-contamination of working surfaces in the kitchen environment. The epidemiology of human salmonellosis has not changed during the past decade. Surveillance remains a powerful tool for protecting the consumer by discovering on-going epidemics, but it has done little to control the endemic problem from which epidemics emerge. Several outbreaks during the past decade indicate that the infecting dose, at least for certain Salmonella strains in certain foods, is considerably lower than that indicated on the basis of volunteer studies with adult male prisoners. The National Research Council report, as well as those from numerous other groups, emphasized the need for consumer education if the incidence of food-associated outbreaks is to be reduced. The rising incidence of human salmonellosis indicates that consumer education programs have not been successful. It was suggested that courses of study in proper food handling practices could profitably be directed toward students in secondary schools and that as a result, on a long term basis, the incidence of foodborne illness, including salmonellosis, would be reduced. Since a large percentage of outbreaks is traced to mishandling of foods in commercial establishments, it was suggested that inspectional activities in hotels, restaurant and catering facilities be increased at the expense of decreased activities in food processing facilities.

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