scholarly journals A handy, accurate, invertible and integrable expression for Dawson’s function

2019 ◽  
Vol 29 ◽  
pp. 1-18
Author(s):  
U. Filobello-Nino ◽  
H. Vazquez-Leal ◽  
A. L. Herrera-May ◽  
R. C. Ambrosio-Lazaro ◽  
R. Castaneda-Sheissa ◽  
...  
Keyword(s):  
Approximate Solution ◽  
Heat Conduction ◽  
Relative Error ◽  
Heat Conduction Problem ◽  
Absolute Error ◽  
Elementary Functions ◽  
Maximum Absolute Error ◽  
Integral Approximation ◽  
Analytical Approximate Solution

This article proposes a handy, accurate, invertible and integrable expression for Dawson’s function. It can be observed that the biggest relative error committed, employing the proposed approximation here, is about 2.5%. Therefore, it is noted that this integral approximation to Dawson’s function, expressed only in terms of elementary functions, has a maximum absolute error of just 7 × 10-3. As a case study, the integral approximation proposed here will be applied to a nonclassical heat conduction problem, contributing to obtain a handy, accurate, analytical approximate solution for that problem

Investigation of Heat Transfer for Shell-Tube Fuel-Cooled Heat Exchanger

2013 ◽  
Vol 378 ◽  
pp. 459-465
Author(s):  
Ya Guo Lu ◽  
Peng Fei Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Relative Error ◽  
Absolute Error ◽  
Heat Transfer Characteristics ◽  
Shell Side ◽  
Transfer Characteristics ◽  
Aero Engine ◽  
The Absolute

A calculate method based on ε-NTU model for heat transfer characteristics of shell-tube fuel-cooled heat exchanger of aero-engine lubrication system was built. The heat convection coefficient was obtained by a dimensionless curve (Re~StPr2/3), which was detailed introduced as well. A case study was executed at last. The absolute error of the outlet lubrication of the tube side and the shell side between the value of calculation and experiment was less than ±10°C, and the relative error was less than 6.5%. The absolute error of the heat transferred between calculation and experiment was less than ±0.9kW, and the relative error was less than 7.4%. It indicates that the mothod is available for the investigation of heat transfer characteristics of shell-tube fuel-cooled heat exchanger.

scholarly journals An Analytical Approximate Solution for the Quasi-Steady State Michaelis-Menten Problem

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
U. Filobello-Nino ◽  
H. Vazquez-Leal ◽  
R. Castaneda-Sheissa ◽  
V. M. Jimenez-Fernandez ◽  
A. L. Herrera-May ◽  
...  
Keyword(s):  
Approximate Solution ◽  
Steady State ◽  
Perturbation Method ◽  
Numerical Solutions ◽  
Absolute Error ◽  
Quasi Steady State ◽  
General Behaviour ◽  
Analytical Approximate Solution

This article utilizes perturbation method (PM) to find an analytical approximate solution for the Quasi-Steady-State Michaelis-Menten problem. From the comparison of Figures and absolute error values, between approximate and numerical solutions, it is shown that the obtained solutions are accurate, and therefore, they explain the general behaviour of the Michaelis-Menten mechanism.

Pressurization of a Solidifying Sphere

1972 ◽  
Vol 39 (1) ◽  
pp. 71-77 ◽  
Author(s):  
K. H. Hsiao ◽  
J. E. Cox ◽  
P. G. Hedgcoxe ◽  
L. C. Witte
Keyword(s):  
Aluminum Alloy ◽  
Approximate Solution ◽  
Heat Conduction ◽  
Thermal Stress ◽  
Steady State ◽  
Heat Conduction Problem ◽  
Solid Shell ◽  
Stress Distributions ◽  
Dimensionless Form ◽  
Molten Material

The pressurization in a solidifying sphere of molten material (initially at a uniform melting temperature) immersed in an infinite cooling medium is presented. The steady-state approximate solution applied to the heat-conduction problem with change of phase (the Stefan problem) provides the temperature distribution in the shell and rate of solidification, which can be employed in the evaluation of the pressurization stress and thermal stress distributions in the solid shell. Stress distributions are evaluated and plotted in dimensionless form. Additional results are presented for the specific case of aluminum alloy.

scholarly journals Development of Digital Scale Based on Fluxgate Sensor

2016 ◽  
Vol 1 ◽  
Author(s):  
Mitra Djamal
Keyword(s):  
Magnetic Field ◽  
Relative Error ◽  
Output Voltage ◽  
Absolute Error ◽  
Maximum Relative Error ◽  
Maximum Absolute Error ◽  
Sensor Development ◽  
Fluxgate Sensor ◽  
Excitation Coil ◽  
The Magnetic Field

<p>Fluxgate is a magnetic sensor which works by comparing the measurement magnetic field with the magnetic field reference. This research aims to develop digital scales using fluxgate sensor. The steps involved were sensor development, characterization, distance and mass calibration of the fabricated sensor. Here, a digital scale based on fluxgate sensor with oval vitrovac 6025Z type core, 360 windings of excitation coil and 240 windings of pick up coil was successfully fabricated. Characterization result shows that the sensor has 1669.2 mV/μT sensitivity and working area of about ± 1.9 μT, with maximum absolute error found out to be around 0.0573 μT with maximum relative error is 1.464 %. Calibrated sensor value obtained reveals that the sensor works from 15.86 until 27.00 mm in distance, utilizing equation of relationship between mass and output voltage  with the maximum relative error obtained as low as 1.49 %.</p>

scholarly journals Development of Digital Scale Based on Fluxgate Sensor

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Mitra Djamal
Keyword(s):  
Magnetic Field ◽  
Relative Error ◽  
Output Voltage ◽  
Absolute Error ◽  
Maximum Relative Error ◽  
Maximum Absolute Error ◽  
Sensor Development ◽  
Fluxgate Sensor ◽  
Excitation Coil ◽  
The Magnetic Field

<p>Fluxgate is a magnetic sensor which works by comparing the measurement magnetic field with the magnetic field reference. This research aims to develop digital scales using fluxgate sensor. The steps involved were sensor development, characterization, distance and mass calibration of the fabricated sensor. Here, a digital scale based on fluxgate sensor with oval vitrovac 6025Z type core, 360 windings of excitation coil and 240 windings of pick up coil was successfully fabricated. Characterization result shows that the sensor has 1669.2 mV/μT sensitivity and working area of about ± 1.9 μT, with maximum absolute error found out to be around 0.0573 μT with maximum relative error is 1.464 %. Calibrated sensor value obtained reveals that the sensor works from 15.86 until 27.00 mm in distance, utilizing equation of relationship between mass and output voltage  with the maximum relative error obtained as low as 1.49 %.</p>

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