scholarly journals The Antikythera Mechanism: The Prove of the Accuracy of the Astronomical Calculations Based on It

Heritage ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 3848-3878
Author(s):  
Kyriakos Efstathiou ◽  
Marianna Efstathiou ◽  
Alexandros Basiakoulis ◽  
Neofytos Kokkinos
Keyword(s):  
Analogue Computer

The Antikythera Mechanism is the oldest extant complex geared device, an amazing analogue computer. It was built approximately 2,150 years ago. The device was operated manually by a user, setting a date in a dial. All necessary calculations were made using a set of gears (at least 39), while the results were displayed on several scientific scales. The Mechanism was used to calculate astronomical phenomena, such as solar and lunar eclipses. After an extensive description of the Mechanism, the main objective of the following paragraphs is to demonstrate the accuracy of its predictions.

Electric analogue computer for complex vectors

1954 ◽  
Vol 31 (3) ◽  
pp. 112-112
Author(s):  
Technology Instrument Corporation
Keyword(s):  
Analogue Computer

The Reduction of Bias Error in Transfer Function Estimates Using FFT-Based Analyzers

1984 ◽  
Vol 106 (1) ◽  
pp. 29-35 ◽  
Author(s):  
P. Cawley
Keyword(s):  
Transfer Function ◽  
Random Excitation ◽  
Analogue Computer ◽  
Bias Error ◽  
Testing Time ◽  
Theoretical Predictions ◽  
Set Up ◽  
Modal Mass ◽  
Time Required ◽  
Good Agreement

The susceptibility to bias error of two methods for computing transfer (frequency response) functions from spectra produced by FFT-based analyzers using random excitation has been investigated. Results from tests with an FFT analyzer on a single degree-of-freedom system set up on an analogue computer show good agreement with the theoretical predictions. It has been shown that, around resonance, the bias error in the transfer function estimate H2 (Syy/Sxy*) is considerably less than that in the more commonly used estimate, H1 (Sxy/Sxx). The record length, and hence the testing time, required for a given accuracy is reduced by over 50 percent if the H2 calculation procedure is used. The analysis has also shown that if shaker excitation is used on lightly damped structures with low modal mass, it is important to minimize the mass of the force gage and the moving element of the shaker.

A discussion on D and E region winds over Europe - Results of E-layer drift measurements at De Bilt

1972 ◽  
Vol 271 (1217) ◽  
pp. 485-497 ◽  
Keyword(s):  
Harmonic Analysis ◽  
Correlation Functions ◽  
Cross Correlation ◽  
Analogue Computer ◽  
On Line ◽  
E Region ◽  
Spaced Receiver Method

At the beginning of 1969 an elaborate programme of E-layer drift measurements was started at De Bilt. The closely spaced receiver method is being used in combination with an on-line analogue computer which plots the polarity-, auto- and cross-correlation functions of the fading signals. The following results over 1969 and a part of 1970 are presented and discussed: mean hourly values of the N and E components for each month; harmonic analysis and prevailing winds, comparison between results obtained from the intersection of the correlation curves and from the time shifts for maximum cross-correlation; and comparison with the results from other stations at about the same latitude.

Analogue computer

1959 ◽  
Vol 36 (7) ◽  
pp. 334-334
Author(s):  
Solartron Electronic Group Ltd.
Keyword(s):  
Analogue Computer

scholarly journals Proton translocation coupled to quinol oxidation in ox heart mitochondria

1973 ◽  
Vol 136 (3) ◽  
pp. 711-720 ◽  
Author(s):  
Hugh G. Lawford ◽  
Peter B. Garland
Keyword(s):  
Proton Translocation ◽  
Mitochondrial Protein ◽  
Glass Electrode ◽  
Measuring System ◽  
Heart Mitochondria ◽  
Analogue Computer ◽  
Back Flow ◽  
Ubiquinol Oxidase ◽  
True Value ◽  
Proton Generation

The suitability of ubiquinol1 and duroquinol as pulse reductants for initiating respirationdriven proton translocation by aerobic ox heart mitochondria was investigated. At 25°C the Vmax. for oxidation was close to 280nmol of quinol oxidized/min per mg of protein, and the Km values were 8μm for ubiquinol1 and 28μm for duroquinol. Pulses of ubiquinol1 and duroquinol were rapidly and completely oxidized by aerobic mitochondria with a simultaneous acidification of the suspending medium as detected with a glass electrode. The →H+/2e−ratios (Mitchell, 1966) calculated from the observed extent of acidification and the amount of quinol added were 3.62 for ubiquinol1 and 2.98 for duroquinol. These values are underestimates of the true value owing to proton back-flow across the membrane. An analogue computer model was used to correct the observed extent of respirationdriven acidification for proton back-flow. The corrected →H+/2e−values were 4.01 for ubiquinol and 3.86 for duroquinol oxidation. Attempts to measure the rate of proton translocation with a pH-measuring system with a response time of 0.4s were not entirely satisfactory, owing to the relative slowness of the electrode response. Nevertheless the maximal rate of proton generation during ubiquinol1 oxidation was about 1200ng-ions of H+/min per mg of mitochondrial protein. It is concluded, contrarily to Chance & Mela (1967), that mitochondria exhibit a proton-translocating ubiquinol oxidase activity with a →H+/2e−ratio of 4.0.

Analogue computer for net adjustment

1962 ◽  
Vol 19 ◽  
pp. 521-524 ◽  
Author(s):  
D.F. Amer
Keyword(s):  
Analogue Computer
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