Stochastic Characterization of Macro- and Microerrors of Journal Bearing Roundness

1977 ◽  
Vol 99 (2) ◽  
pp. 327-334 ◽  
Author(s):  
B. Velsher ◽  
M. O. M. Osman ◽  
T. S. Sankar
Keyword(s):  
Journal Bearing ◽  
Form Error ◽  
Measuring Device ◽  
New Approach ◽  
Measuring Devices ◽  
Stochastic Characterization ◽  
Round Surface ◽  
Hybrid Computer ◽  
The Mathematical Model

A new approach for the characterization of form error and surface roughness of round bearings is presented. The method employs the theory of random function excursions to describe the macro- and microerrors of the round surface in both radial and circumferential directions. The mathematical principle of the measuring technique is given, and it is shown that an accurate description of the roundness can be obtained from the knowledge of the intercept probabilities of the crest and valley excursions of the surface trace about a given reference circle. Based on the mathematical model, new indices for the characterization of journal bearing roundness are proposed. These indices are computed directly from data obtained from commercially available roundness measuring devices. A number of experiments were performed to justify the validity of the proposed roundness indices. Roundness measurements were carried out on a number of differently machined cylinders using a specially equipped measuring device (Talyrond 51) with a link to a hybrid computer EAI-690. The theoretically computed indices compared favorably with the measurements made on the actual round surfaces.

Profile Characterization of Manufactured Surfaces Using Random Function Excursion Technique—Part 1: Theory

1975 ◽  
Vol 97 (1) ◽  
pp. 190-195 ◽  
Author(s):  
T. S. Sankar ◽  
M. O. M. Osman
Keyword(s):  
Surface Texture ◽  
Low Cost ◽  
Measuring Device ◽  
Rolling Circle ◽  
Measuring Devices ◽  
Texture Parameters ◽  
Probability Densities ◽  
On Line ◽  
Excursion Probability

This paper discusses a new approach for describing accurately the typology of manufactured surfaces. The method employs the theory of stochastic excursions to characterize the surface texture in the amplitude and lengthwise directions. The mathematical principle behind the approach is briefly explained, and it is shown that an accurate description of the roughness can be obtained from the knowledge of the intercept probabilities of the crest and valley excursions of the surface texture about any given level, say the CLA value, specified with respect to the mean line. Based on the preceding excursion probability densities, new surface texture parameters are proposed. These parameters may be computed directly from the surface roughness data obtained from commercially available measuring devices. On the basis of this investigation, it is feasible to develop a low-cost measuring device for “on-line” surface evaluation in production. It is also shown that the sampling length provides a geometrically well-defined filter characteristic similar to that of the rolling circle radius in the E-system.

Computer-aided monitoring and operation of continuous measuring devices

2004 ◽  
Vol 50 (11) ◽  
pp. 31-39 ◽  
Author(s):  
L. Rieger ◽  
M. Thomann ◽  
A. Joss ◽  
W. Gujer ◽  
H. Siegrist
Keyword(s):  
Control Charts ◽  
Measuring System ◽  
Measuring Device ◽  
Supervisory System ◽  
Monitoring Frequency ◽  
Measuring Devices ◽  
Monitoring Effort ◽  
Continuous Measuring ◽  
And Control

Extended studies of measuring and control systems in activated sludge plants at EAWAG revealed that the measuring devices remain the weakest point in control applications. To overcome this problem, a software package was developed which analyses and evaluates the residuals between a reference measurement and the sensor and collects the information in a database. The underlying monitoring concept is based on a two-step evaluation of the residuals by means of statistical evaluations using control charts with two different sets of criteria. The first step is a warning phase in which hints on probable errors trigger an increase in the monitoring frequency. In the second step, the alarm phase, the error hypothesis has to be validated and should allow immediate and targeted reactions from the operator. This procedure enables an optimized and flexible monitoring effort combined with an increased probability of early detection of systematic measuring errors. Beside the monitoring concept, information about the measuring device, the performed servicing actions and the responsibilities is stored. Statistical values for the quantitative characterization of the measuring system during operation will be given. They are needed to parameterise controllers or to guarantee the accuracy of the instrument in order to allow reliable calculations of effluent tax. In contrast to other concepts, not only is the measuring device examined under standard conditions, but so is the entire measuring chain from the liquid to be analysed to the value stored in the database of the supervisory system. The knowledge of the response time of the measuring system is then required in order to allow a comparison of the corresponding values.

scholarly journals Sustainability Investigation of Vehicles’ CO2 Emission in Hungary

2021 ◽  
Vol 13 (15) ◽  
pp. 8237
Author(s):  
István Árpád ◽  
Judit T. Kiss ◽  
Gábor Bellér ◽  
Dénes Kocsis
Keyword(s):  
Energy Efficiency ◽  
Co2 Emissions ◽  
Energy Supply ◽  
Internal Combustion Engines ◽  
Combustion Engines ◽  
The European Union ◽  
New Approach ◽  
Technology System ◽  
Low Co2

The regulation of vehicular CO2 emissions determines the permissible emissions of vehicles in units of g CO2/km. However, these values only partially provide adequate information because they characterize only the vehicle but not the emission of the associated energy supply technology system. The energy needed for the motion of vehicles is generated in several ways by the energy industry, depending on how the vehicles are driven. These methods of energy generation consist of different series of energy source conversions, where the last technological step is the vehicle itself, and the result is the motion. In addition, sustainability characterization of vehicles cannot be determined by the vehicle’s CO2 emissions alone because it is a more complex notion. The new approach investigates the entire energy technology system associated with the generation of motion, which of course includes the vehicle. The total CO2 emissions and the resulting energy efficiency have been determined. For this, it was necessary to systematize (collect) the energy supply technology lines of the vehicles. The emission results are not given in g CO2/km but in g CO2/J, which is defined in the paper. This new method is complementary to the European Union regulative one, but it allows more complex evaluations of sustainability. The calculations were performed based on Hungarian data. Finally, using the resulting energy efficiency values, the emission results were evaluated by constructing a sustainability matrix similar to the risk matrix. If only the vehicle is investigated, low CO2 emissions can be achieved with vehicles using internal combustion engines. However, taking into consideration present technologies, in terms of sustainability, the spread of electric-only vehicles using renewable energies can result in improvement in the future. This proposal was supported by the combined analysis of the energy-specific CO2 emissions and the energy efficiency of vehicles with different power-driven systems.

scholarly journals An Intrinsic Characterization of Five Points in a CAT(0) Space

2020 ◽  
Vol 8 (1) ◽  
pp. 114-165
Author(s):  
Tetsu Toyoda
Keyword(s):  
Metric Space ◽  
Isometric Embedding ◽  
Metric Spaces ◽  
Necessary Conditions ◽  
New Approach ◽  
Intrinsic Characterization ◽  
New Family

AbstractGromov (2001) and Sturm (2003) proved that any four points in a CAT(0) space satisfy a certain family of inequalities. We call those inequalities the ⊠-inequalities, following the notation used by Gromov. In this paper, we prove that a metric space X containing at most five points admits an isometric embedding into a CAT(0) space if and only if any four points in X satisfy the ⊠-inequalities. To prove this, we introduce a new family of necessary conditions for a metric space to admit an isometric embedding into a CAT(0) space by modifying and generalizing Gromov’s cycle conditions. Furthermore, we prove that if a metric space satisfies all those necessary conditions, then it admits an isometric embedding into a CAT(0) space. This work presents a new approach to characterizing those metric spaces that admit an isometric embedding into a CAT(0) space.

scholarly journals Avoided motifs: short amino acid strings missing from protein datasets

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Function ◽  
Large Protein ◽  
New Approach ◽  
Cellular Context ◽  
Human Proteins ◽  
Context Specific ◽  
Protein Datasets

Abstract According to the amino acid composition of natural proteins, it could be expected that all possible sequences of three or four amino acids will occur at least once in large protein datasets purely by chance. However, in some species or cellular context, specific short amino acid motifs are missing due to unknown reasons. We describe these as Avoided Motifs, short amino acid combinations missing from biological sequences. Here we identify 209 human and 154 bacterial Avoided Motifs of length four amino acids, and discuss their possible functionality according to their presence in other species. Furthermore, we determine two Avoided Motifs of length three amino acids in human proteins specifically located in the cytoplasm, and two more in secreted proteins. Our results support the hypothesis that the characterization of Avoided Motifs in particular contexts can provide us with information about functional motifs, pointing to a new approach in the use of molecular sequences for the discovery of protein function.

scholarly journals A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for Robotic Applications

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Experimental Tests ◽  
Humanoid Robots ◽  
Inverse Kinematic ◽  
Element Analysis ◽  
New Approach ◽  
Flexible Polymer ◽  
The Mathematical Model

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.

A new approach to the bienergy and biangle of a moving particle lying in a surface of lorentzian space

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Talat Körpınar ◽  
Yasin Ünlütürk
Keyword(s):  
Vector Fields ◽  
Elastic Surface ◽  
Geometrical Characterization ◽  
Lorentzian Space ◽  
New Approach ◽  
Darboux Vector ◽  
Moving Particle ◽  
The Relationship ◽  
Surface Curve

AbstractIn this research, we study bienergy and biangles of moving particles lying on the surface of Lorentzian 3-space by using their energy and angle values. We present the geometrical characterization of bienergy of the particle in Darboux vector fields depending on surface. We also give the relationship between bienergy of the surface curve and bienergy of the elastic surface curve. We conclude the paper by providing bienergy-curve graphics for different cases.

scholarly journals Introducing the HD+B model for pulsar wind nebulae: a hybrid hydrodynamics/radiative approach

2020 ◽  
Vol 494 (3) ◽  
pp. 4357-4370
Author(s):  
B Olmi ◽  
D F Torres
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Theoretical Modelling ◽  
X Rays ◽  
Pulsar Wind Nebulae ◽  
New Approach ◽  
Energy Gamma ◽  
Radiative Model ◽  
Pulsar Wind

ABSTRACT Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -by far- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper, we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost.

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