scholarly journals Automatic Tolerance Analysis of Permanent Magnet Machines with Encapsuled FEM Models Using Digital-Twin-Distiller

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2077
Author(s):  
Tamás Orosz ◽  
Krisztián Gadó ◽  
Mihály Katona ◽  
Anton Rassõlkin
Keyword(s):  
Tolerance Analysis ◽  
Mean Value ◽  
System Level ◽  
Electrical Machine ◽  
Permanent Magnet Machines ◽  
Fem Model ◽  
Cogging Torque ◽  
Order Of Magnitude ◽  
Manufacturing Tolerances ◽  
The Mean

Tolerance analysis is crucial in every manufacturing process, such as electrical machine design, because tight tolerances lead to high manufacturing costs. A FEM-based solution of the tolerance analysis of an electrical machine can easily lead to a computationally expensive problem. Many papers have proposed the design of experiments, surrogate-model-based methodologies, to reduce the computational demand of this problem. However, these papers did not focus on the information loss and the limitations of the applied methodologies. Regardless, the absolute value of the calculated tolerance and the numerical error of the applied numerical methods can be in the same order of magnitude. In this paper, the tolerance and the sensitivity of BLDC machines’ cogging torque are analysed using different methodologies. The results show that the manufacturing tolerances can have a significant effect on the calculated parameters, and that the mean value of the calculated cogging torque increases. The design of the experiment-based methodologies significantly reduced the calculation time, and shows that the encapsulated FEM model can be invoked from an external system-level optimization to examine the design from different aspects.

Liquid helium films. I. The thickness of the film

1950 ◽  
Vol 203 (1072) ◽  
pp. 119-132 ◽  
Keyword(s):  
Liquid Helium ◽  
Dynamic Method ◽  
Mean Value ◽  
Helium Films ◽  
Helium Ii ◽  
Experimental Factor ◽  
Order Of Magnitude ◽  
The Mean

The thickness ( d ) of the helium II film and its variation with height ( H ) and temperature were measured by a dynamic method involving the oscillations of a meniscus in a capillary. The variation with height could be represented only approximately by the equation d = k/H n , as the effective value of n was greater at smaller values of H . The mean value of n over a range of heights from 0·5 to 5 cm. was 0·14, which is appreciably smaller than the values predicted by the theories so far advanced to explain the formation of the film. The order of magnitude of k was 2 x 10 -6 cm., but it varied slightly with the nature of the surface or some other experimental factor.

scholarly journals On the Accuracy of Error Propagation Calculations by Analytic Formulas Obtained for the Inverse Transformation

2019 ◽  
Vol 64 (3) ◽  
pp. 217
Author(s):  
V. I. Romanenko ◽  
N. V. Kornilovska
Keyword(s):  
Error Propagation ◽  
Random Variable ◽  
Mean Value ◽  
Inverse Transformation ◽  
First Order ◽  
Order Of Magnitude ◽  
The Mean ◽  
Normally Distributed

The accuracy of error propagation calculations is estimated for the transformation x → y = f(x) of the normally distributed random variable x. The estimation is based on the formulas for the error propagation obtained for the inverse transformation y → x of the normally distributed random variable y. In the general case, the calculation accuracy for the mean value and the variance of the random variable y is shown to be of the first order of magnitude in the variance of the random variable x.

PROTEIN-BOUND IODINE IN INFANTS FROM BIRTH TO ONE YEAR OF AGE

PEDIATRICS ◽  
1951 ◽  
Vol 7 (2) ◽  
pp. 240-244
Author(s):  
T. S. DANOWSKI ◽  
S. Y. JOHNSTON ◽  
W. C. PRICE ◽  
M. MCKELVY ◽  
S. S. STEVENSON ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Maternal Blood ◽  
Mean Value ◽  
Elevated Concentration ◽  
Older Children ◽  
Mean Values ◽  
Order Of Magnitude ◽  
The Mean ◽  
One Year ◽  
Relationship Of

Statistical comparisons indicate that within 12 hours of birth the serum protein-bound iodine of the infant is of the same order of magnitude, on the average, as that present in maternal blood during pregnancy or within a few hours of delivery. During the remainder of the first week of life there occurs a transient statistically significant increase in the mean value of this iodine fraction. During the sixth to twelfth week the concentrations fall below those present neonatally, but at this time or at any subsequent age up to 1 year, they are still on the average above those encountered in euthyroid nonpregnant adults or in older children. The possible relationship of these higher mean values in infancy to increased thyroid function in the rapidly growing infant have been mentioned with emphasis on the elevated concentration of circulating thyroxin.

scholarly journals The relative importance of macrophysical and cloud albedo changes for aerosol induced radiative effects in stratocumulus

2016 ◽  
Author(s):  
Daniel P. Grosvenor ◽  
Paul R. Field ◽  
Adrian A. Hill ◽  
Benjamin J. Shipway
Keyword(s):  
Mean Value ◽  
Cloud Microphysics ◽  
Liquid Water Path ◽  
Frequency Distributions ◽  
Cloud Albedo ◽  
Aerosol Loading ◽  
Stratocumulus Clouds ◽  
Order Of Magnitude ◽  
The Mean ◽  
The Impact

Abstract. Aerosol-cloud interactions are explored using 1 km resolution simulations of SE Pacific stratocumulus clouds that include realistic meteorology along with newly implemented cloud microphysics and sub-grid cloud schemes. The model was critically assessed against observations of Liquid Water Path (LWP), broadband fluxes, cloud fraction (fc), droplet number concentrations (Nd) and radar reflectivities. Aerosol loading sensitivity tests showed that at low aerosol loadings, changes to aerosol affected shortwave fluxes equally through changes to cloud macrophysical charateristics (LWP, fc) and cloud albedo changes due solely to Nd changes. However, at high aerosol loadings, only the Nd albedo change was important. Evidence was also provided to show that a treatment of sub-grid clouds is as important as order of magnitude changes in aerosol loading for the accurate simulation of stratocumulus at this grid resolution. Overall, the control model demonstrated a credible ability to reproduce observations suggesting that many of the important physical processes for accurately simulating these clouds are represented within the model and giving some confidence in the predictions of the model concerning stratocumulus and the impact of aerosol. For example, the control run was able to reproduce the shape and magnitude of the observed diurnal cycle of domain mean LWP to within ~ 10 g m−2 for the nighttime, but with an overestimate for the daytime of up to 30 g m−2. The latter was attributed to the uniform aerosol fields imposed on the model, which meant that the model failed to include the low Nd mode that was observed further offshore, preventing the LWP removal through precipitation that likely occurred in reality. The boundary layer was too low by around 260 m, which was attributed to the driving global model analysis. The shapes and sizes of the observed bands of clouds and open-cell-like regions of low areal cloud cover were qualitatively captured. The daytime fc frequency distribution was reproduced to within fc = 0.04 for fc > ~ 0.7 as was the domain mean nighttime fc (at a single time) to within fc = 0.02. Frequency distributions of shortwave top-of-the-atmosphere (TOA) fluxes from satellite were well represented by the model with only a slight underestimate of the mean by 15 %; this was attributed to near--shore aerosol concentrations that were too low for the particular times of the satellite overpasses. TOA longwave flux distributions were close to those from satellite with agreement of the mean value to within 0.4 %. From comparisons of Nd distributions to those from satellite it was found that the Nd mode from the model agreed with the higher of the two observed modes to within ~ 15 %.

Effect of Point and Diffuse Source Loadings on Mercury Concentrations in the Wabigoon River: Evidence of a Seasonally Varying Sediment–Water Partition

1986 ◽  
Vol 43 (7) ◽  
pp. 1426-1444 ◽  
Author(s):  
J. W. Parks ◽  
J. A. Sutton ◽  
A. Lutz
Keyword(s):  
Suspended Solids ◽  
Surface Sediments ◽  
Suspended Sediments ◽  
Mean Value ◽  
Control Site ◽  
Diffuse Source ◽  
Order Of Magnitude ◽  
Summer Temperatures ◽  
High Flows ◽  
The Mean

Ten years after major mercury loadings from a chlor-alkalai plant were sharply reduced, mercury levels in the surface sediments, water, and suspended sediments of the Wabigoon River downstream of Dryden, Ontario, remain markedly elevated. During 1979, a typical water year, average mercury concentrations in water throughout an 80-km reach were nearly five times the mean value at the control site. Elevated mercury levels in the Wabigoon River are primarily due to the chemical and biological remobilization of mercury from sediments. Lesser amounts are due to the erosion of mercury-enriched sediments during high flows and to current releases from the mill site at Dryden. In the absence of resuspended sediment during high flows, mercury levels in contaminated waters can be best described by a sediment – water – suspended solids partition. This condition was established within half a day in the most contaminated portion of the system. Mercury concentrations in water can fluctuate seasonally by an order of magnitude. Highest concentrations were associated with elevated summer temperatures.

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