Circular Part Research Articles

The multidimensional markov chain with prespecified asymptotic means, and (auto-)covariances

In this paper a method is presented to construct random time series which, starting from their present values, converge to stationary time series with a priori specified mean values, standard deviations, correlations and autocorrelations. The method is applied to simulate time series of price-inflation, wage-inflation, and interest rates, whose mean values, standard deviations, correlations and autocorrelations converge to the values which are estimated from historical data This application is a circular part of a Decision Support System which assists management of pension funds in analysing new methods of calculating pension premiums.

Ptolemy's maps of earth and the heavens: A new interpretation

0°. Among Ptolemy's works are two whose mathematical bases historians of science have interpreted in very much the same way. The works are The Planispherium and the cartographic sections of The Geography, and in both cases the interpretation has been in terms of pointwise projection of a portion of the surface of the sphere onto a portion of the plane. In the case of The Planispherium the sphere is the celestial sphere and the mapping appears to be stereographic projection of the portion of the celestial sphere to the north of "the greatest always-invisible circle"1 on the interior of a circular part of the plane. For example, Neugebauer 1975 (857-858) writes "it [The Planispherium] deals with the representation of the celestial sphere . . . known today as stereographic projection", Toomer 1978 (219) writes "the whole necessary theory of stereographic projection is set out in Ptolemy's Planispherium,'" and Pedersen 1974 writes "In the Planispherium ... Ptolemy describes how the celestial sphere can be projected in a different way, namely by stereographic (central) projection from the southern pole of the heavens onto the plane of the equator." In the case of The Geography however the sphere is the terrestrial globe and, in addition to Marinus's much-criticized representation of its surface, Ptolemy gives three other representations of the inhabited portion of the earth (the oikoumene in the language of Greek geographers) onto plane regions of varying shapes. Here again, the best of the recent literature on the topic has set forth Ptolemy's representations in terms of pointwise maps or projections of the sphere into the plane. Some examples are the analyses of F. Hopfner in the appendices to Mžik & Hopfner 1938 and the summary in Neugebauer 1975 (879-890).

Shape matching using optimization techniques

Automated vision inspection systems are the most versatile non-contact inspection systems. They are fast, compact, and remarkably accurate, thereby making 100% on-line inspection possible in modern manufacturing systems. Roundness in one of the basic geometric elements in engineering design and manufacturing. As a result its inspection is an important part of the inspection of many industrial parts. This paper presents two least-squares techniques to determine the out-of-roundness error of circular production parts. This error is measured with respect to an ideal circle of specified radius.

Characterization of Si-Rich WSix on Si

The structural change of CVD WSi2.6 by annealing in vacuum and in oxygen atmosphere has been studied. By annealing in vacuum, the first phenomenon, which occurs at 400°C, is crystallization of the amorphous film to a metastable semiconducting hexagonal WSi2. Excess Si in WSi2.6 has already precipitated at the WSi2/Si interface. The second phenomenon, which occurs at 600°C, is the phase transformation of the hexagonal structure to the tetragonal one. Above 1000°C, the precipitated excess Si grows epitaxially on the Si(100) substrate, while a SiO2 layer is formed by oxidizing above 700°C. The film thickness of the SiO2 layer increases with the increase of the oxidation temperature. Owing to the increment of the film thickness, the interface between WSi2 and Si moves into the Si substrate. Moreover, there are some circular parts crystallized as a tetragonal SiO2 (α-cristobalite) of about 5 μm in diameter.

The minimax center estimation problem for automated roundness inspection

Significant advances in computer technology, sensing devices, pattern recognition and image processing techniques have made the on-line inspection of all production parts a feasible option in modern manufacturing systems. This study is concerned with the development of efficient algorithms to determine the out-of-roundness error for automated inspection of circular production parts. The out-of-roundness error is defined as the maximum deviation of a given sey of sample points, taken from the boundary of the part, from the so called minimax circle.

Transmission loss of a 125- mu m diameter PANDA fiber with circular stress-applying parts

The transmission loss of a 125- mu m diameter polarization-maintaining and absorption-reducing optical fiber (the PANDA fiber) with circular stress-applying parts (SAPs) has been investigated. The loss is calculated at a 1.55- mu m wavelength for SAPs consisting of B/sub 2/O/sub 3/ doped silica glasses. The experimental measurements show the validity of the analysis. It is shown that, when the half distance between SAPs is more than 2.2 times the core radius, the additional transmission loss due to B/sub 2/O/sub 3/ absorption is less than 0.05 dB/km with normalized frequency of 2.2 to 2.4 and a B/sub 2/O/sub 3/ dopant concentration of 20 mol.%. As a result, it has been confirmed that transmission losses of 125- mu m diameter PANDA fibers can be comparable to those of commercially available single-mode optical fibers. >

Automated inspection of circular parts : Jose A. Ventura, C. Alec Chang and Cerry M. Klein. Comput. Ind. Engng15, 349 (1988)

Automated inspection of circular parts : Jose A. Ventura, C. Alec Chang and Cerry M. Klein. Comput. Ind. Engng15, 349 (1988)

A putative replicative form of the abutilon mosaic virus (gemini group) in a chromatin-like structure

The putative replicative form of the abutilon mosaic virus (AbMV), a geminivirus, was purified from infected plants. It was shown to consist of a bipartite genome of 2660 and 2640 bp. This double-stranded DNA has a closed or relaxed circular conformation and part of it is packed in nucleoprotein complexes with a chromatin-like structure. Similarities between the geminiviruses and the animal simian virus 40 are discussed against this back-ground.

複数の３点法を用いた円形部品の断面形状と回転精度を同時に測定する方法

On the direct measurement of roundness of cylinder, the reading of the indicator generally includes the rotating error of the measuring system. However the measurement system of roundness using a vee block and indicator has no rotating errors in the readings. The most serious disadvantage of this arrangement lies in the difficulty of establishing the actual shape of the circular parts by the readings of the dial indicator, which will depend on the used angle of the vee block and on the number of lobes present on the circular part. But this disadvantage will be now improved by applying this arrangement procedure since the calculated or analyzed values of the readings will be able to establish the actual shape of the circular parts if the values will be selected suitably. The selected angles of the vee block are used 60°, 90°, .120°, .135° and 180° in this experiment. By this procedure the standard shape will be able not only to measure but also to know the rotating accuracy of the measuring system.

Automated inspection of circular parts

Automated vision inspection systems are the most versatile non-contact inspection systems. They are fast, compact, and remarkably accurate, thereby making 100% on-line inspection possible in modern manufacturing systems. Roundness in one of the basic geometric elements in engineering design and manufacturing. As a result its inspection is an important part of the inspection of many industrial parts. This paper discusses least-squares and minimax mathematical models and algorithms to determine the out-of-roundness error in automated roundness inspection. These errors are measured with respect to an ideal circle of specified radius.

In-vivo degradation pathway of an excised intervening sequence

A study of the distribution in heterogeneous nuclear RNP (hnRNP) of the different forms of the first intervening sequence (IVSI) from the E3 transcription unit of adenovirus serotype 2 suggests a three-step pathway for IVS excision and degradation. First, the lariat IVS is formed in a large RNP of the size of premessenger RNP where it is resistant to nuclease attack. Second, the lariat IVS is released from this large structure as a small RNP where it is very susceptible to enzymic degradation. Third, the lariat IVS is linearized after the release of the small RNP. Our studies suggest that only the intact lariat and linear IVS are involved in the excision-degradation pathway in vivo, whereas the lariat nicked in its circular part and the IVS trimmed at its 3' end are not pre-existing but generated during isolation of hnRNA or hnRNP.

The Fibre Content Distribution of Compression Molded Long Fibre-Reinforced Thermoplastic Products**

Abstract A method is proposed which can be used to calculate the fibre content distribution of compression molded long fibre-reinforced thermoplastic products for isothermal state. The fibre is assumed to be a sphere or a circular cylinder, and slab-shaped or circular-shaped parts are simulated. Comparision with experiments shows that the method accurately predicts the distribution. The effects of molding-process variables on the distribution are also presented.

A Theoretical Study on the Role of a Circular Part of Radial-Circular Networks

A Theoretical Study on the Role of a Circular Part of Radial-Circular Networks

LAMINAR MIXED CONVECTION IN A SYMMETRICALLY OR ASYMMETRICALLY HEATED VERTICAL CHANNEL

A numerical investigation is made of laminar mixed convection of air in a vertical channel. The thermal boundary conditions considered are symmetric heating, where both plates are heated, and asymmetric heating, where one plate is heated and the other is adiabatic. Results are obtained for Rayleigh numbers of 10 3 W. T. Lawrence and J. C. Chato , Heat Transfer Effects on the Developing Laminar Flow inside Vertical Tube , J. Heat Transfer , vol. 88 , no. 2 , pp. 214 – 222 , 1966 .[Crossref], [Web of Science ®] , [Google Scholar], 10 5 W. L. Wang and P. A. Longwell Laminar Flow in the Inlet Section of Parallel Plates , AIChEJ. , vol. 10 , no. 3 , pp. 323 – 329 , 1964 .[Crossref], [Web of Science ®] , [Google Scholar], and 10 6 J. S. Vrentas , J. L. Duda , and K. G. Bargeron , Effect of Axial Diffusion of Vorticity on Flow Development in Circular Conduits Part 1, Numerical Solutions , AIChE J. , vol. 12 , no. 5 , pp. 837 – 844 , 1966 .[Crossref], [Web of Science ®] , [Google Scholar] and Gr/Re 2 L. N. Tao On Combined Free and Forced Convection in Channels , J. Heat Transfer , vol. 82 , no. 3 , pp. 233 – 238 , 1960 .[Crossref] , [Google Scholar] values of 0.1, 1, 3, and 5. The temperatures are observed to increase with increasing Gr/Re 2 L. N. Tao On Combined Free and Forced Convection in Channels , J. Heat Transfer , vol. 82 , no. 3 , pp. 233 – 238 , 1960 .[Crossref] , [Google Scholar] and decreasing Rayleigh number. The velocity profile peaks near the hot plates and exhibits a concavity, which, in the symmetric heating case, occurs around the centerline. With increasing Gr/Re 2 L. N. Tao On Combined Free and Forced Convection in Channels , J. Heat Transfer , vol. 82 , no. 3 , pp. 233 – 238 , 1960 .[Crossref] , [Google Scholar] the velocity near the hot wall increases while the velocity near the centerline decreases. The Nusselt number attains its maximum value near the inlet of the channel and increases with decreasing Gr/Re 2 L. N. Tao On Combined Free and Forced Convection in Channels , J. Heat Transfer , vol. 82 , no. 3 , pp. 233 – 238 , 1960 .[Crossref] , [Google Scholar] values.

The Stability of Fluid Filled, Circular Cylindrical Pipes Part I - Theoretical Solutions

It was shown previously that the usual engineering approach to the problem of shell stability conforms with the more general variational method. Whereas the former entails the equilibrium of all forces acting on an infinitesimal element at incipient buckling, the latter simply replaces the load terms in the general differential equations of equilibrium by equivalent “parametric” or “reduced” loads. The theory is applied to the applied to the problem of the circular, thin walled pipe acting as a simply supported beam containing fluid to any arbitrary level. By expressing the displacements and compatible internal loads in doubly infinite Fourier series which satisfy geometric and natural boundary conditions and using a Bubnov-Galerkin technique, it is possible to obtain estimates of he critical fluid density required to buckle the shell. Two cases of buckling are examined involving full and partially loaded pipes and the solution is seen to be sensitive to the number and location of harmonics included in the numerical calculations. Some logarithmic relationships are proposed between the buckling load and the shell parameters defining length and sectional slenderness. It is shown that the results can be conveniently interpreted using the parameter K which defines the nature of the stress field.

On the Hypothesis of Local Determinability and a Concise Stress-Strain Relation for Curved Strain Path

The hypothesis of local determinability proposed by V.S. Lensky was experimentally confirmed to hold with high accuracy on a curved part of strain path. That is, a rate dθ/ds (θ is a difference between directions of stress and strain increment vectors, and s is a length of strain path) depends only on the current values of θ(s) and curvature K(s) of strain path. Experiments were performed along some strain paths with two circular parts in a two-dimensional space of strain, by applying combined loads of axial force and torque to thin-walled tubular specimens of initially isotropic brass. A simple stress-strain relation which reflects the curvature effect was formulated by using the hypothesis for a practically important set of strain paths with intermediate curvature.

A formed filter paper medium for microdroplet analyses of liquid samples by X‐ray fluorescence spectrometry

AbstractA new type of a formed filter paper is proposed as a sample medium for a microdroplet analysis by x‐ray fluorescence spectrometry. It has a circular center part, separated by a narrow circular groove from its edge, and four, paraffined, supporting bridges. It can thus keep a spot area constant when a liquid sample drops at the center part. After dropping the liquid sample, the paper is dried and used for the x‐ray measurement. It can be stored for years without any chemical change. This formed filter paper is effective in improving the linearity range of a calibration curve and the precision of a fluorescent x‐ray measurement as compared with a non‐formed filter paper. The sample volume required is only 20 to 100 μ1 and therefore microscale analysis of the liquid sample is allowable.

A new method for quantitative X-ray analysis of multiphase mixtures

This new method for quantitative X-ray analysis of multiphase mixtures is based on transmission measurements of thin samples in combination with absorption measurements from defined circular parts of these samples. The method has the advantage that only a few (1–5) mg of substance are required. There is no limitation on the number of phases because no matrix problems exist. The automated method is safe in operation since the measured intensities (Ed) and absorption factors (S) can be checked for consistency. The measurements are made with monochromatic Cu Kα (or Co Kα) radiation on the STOE/CSS automatic focusing X-ray powder diffractometer. The optical principle of the diffractometer and the theoretical basis of the method are described. The practical use of the method and two examples of analyses are given.

Vibrations of a plate with an elastic constraint of eccentric circular part

In this paper, a method for solving vibration problems of a viscoelastic plate having an eccentric circular constraint is presented. The frequency equation in a complex form for the plate with arbitrary shape is obtained. Numerical calculations are carried out for two cases of a circular plate with an eccentric circular stepped surface and a circular plate on an eccentric elastic foundation. The nondimensional natural frequencies and the logarithmic decrements are given for these plates.

Let's Do It: The Surprising Circle!

What do you know about a circle? Often we consider only its measurements and fail to look at its other properties. What happens when you put several circles together or look at parts of a circle? Are looks deceiving? A circle looks so perfect and round, but can it fool you? Can it lead you on extensive searches? Can it produce unusual designs? What can you do with circular shapes and parts of circular shapes?