scholarly journals Unit Conversion Factor

2020 ◽  
Author(s):  
Keyword(s):  
Conversion Factor ◽  
Unit Conversion Factor ◽  
Unit Conversion

scholarly journals Quality Control of Display Devices for Medical Radiodiagnosis Employing the Standard TG18, GSDF and JND

2018 ◽  
Vol 6 (1) ◽  
pp. 21-32
Author(s):  
Bruno Ribeiro de Mesquita ◽  
C. Ferreira ◽  
Divanizia do Nascimento Souza
Keyword(s):  
Medical Diagnosis ◽  
Conversion Factor ◽  
American Association ◽  
Just Noticeable Difference ◽  
Display Devices ◽  
Digital Devices ◽  
Unit Conversion Factor ◽  
Display Function ◽  
Unit Conversion

Introduction: This work presents a study on the procedures for evaluating the quality of imaging display devices in radiology, considering the characteristic luminance curve obtained experimentally versus the Just Noticeable Difference (JND) and the lifetime of digital display devices. Materials & Methods: The evaluations were done using image patterns published by the American Association of Physicists in Medicine on Digital Imaging and Communication in Medicine (DICOM) and the Grayscale Standard Display Function (GSDF), viewed in DICOM software, with various shades of gray. A digital luximeter was used as the luminance meter. A correlation with the time of use of the devices was performed to classify the digital devices as primary (suitable for medical diagnosis) or secondary (suitable only for visualization of medical images). Results & Discussion: Among the monitors evaluated, those with a resolution between 2 and 5 megapixels were classified as primary for up to 50, 000 hours of use, and some above that time limit present behavior equivalent to secondary monitors. Monitoring the temporal evolution of the use of devices is important to avoid errors in medical diagnosis. Conclusion: The use of a calibrated digital luximeter with an illuminance unit conversion factor in luminance defined by this equipment was shown to be an alternative to replace a photometer when this latter is not available.

Definition of an HBsAg to DNA international unit conversion factor by enrichment of circulating hepatitis B virus forms

2015 ◽  
Vol 22 (9) ◽  
pp. 718-726 ◽  
Author(s):  
N. Désiré ◽  
Y. Ngo ◽  
J.-F. Franetich ◽  
L. Dembele ◽  
D. Mazier ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Conversion Factor ◽  
International Unit ◽  
Unit Conversion Factor ◽  
B Virus ◽  
Definition Of ◽  
Unit Conversion

A Novel Analytical Fracture-Permeability Model Dependent on Both Fracture Width and Proppant-Pack Properties

SPE Journal ◽  
2020 ◽  
Vol 25 (06) ◽  
pp. 3031-3050
Author(s):  
Bailu Teng ◽  
Huazhou Li ◽  
Haisheng Yu
Keyword(s):  
A Priori ◽  
Brinkman Equation ◽  
Fracture Permeability ◽  
Permeability Model ◽  
Fracture Conductivity ◽  
Fracture Width ◽  
Unit Conversion Factor ◽  
Viscous Shear ◽  
Unit Conversion ◽  
Darcy Parameter

Summary For an empty fracture, the fracture permeability (kf) is mainly influenced by the effect of viscous shear from fracture walls and can be analytically estimated if the fracture width (wf) is known a priori (i.e., kf=β2wf2/12, where β2 is the unit-conversion factor). For an adequately propped fracture, the fracture permeability is mainly influenced by the proppant-pack properties and can be approximated with the proppant-pack permeability (kf=kp, where kp is proppant-pack permeability). It can be readily inferred that as the effect of viscous shear fades (or the proppant-pack effect becomes pronounced), there should be a regime within which both the viscous shear and the proppant-pack properties exert significant influences on the fracture permeability. However, the functional relationship between fracture permeability, viscous shear (or fracture width), and proppant-pack properties is still elusive. In this work, we propose a new fracture-permeability model to account for the influences of the proppant-pack permeability, proppant-pack porosity (ϕp), and fracture width on the fracture permeability. This new fracture-permeability model is derived from a modified Brinkman equation. The results calculated with the fracture-permeability model show that with different values of the Darcy parameter, the fluid flow can be divided into viscous-shear-dominated (VSD) regime, transition regime, and Darcy-flow-dominated (DFD) regime. If the Darcy parameter is sufficiently large, the effect of proppant-pack permeability on fracture permeability can be neglected and the fracture permeability can be calculated with the VSD fracture-permeability (FP) (VSD-FP) equation (i.e., kf=β2ϕpwf2/12). If the Darcy parameter is sufficiently small, the effect of viscous shear on fracture permeability can be neglected and the fracture permeability can be calculated with the DFD-FP equation (i.e., kf=kp). Both the VSD-FP and DFD-FP equations are special forms of the proposed fracture-permeability model. For the existing empirical/analytical fracture-conductivity models that neglect the effect of viscous shear, one can multiply these models by the coefficient of viscous shear to make these models capable of estimating the fracture conductivity with large values of Darcy parameter.

Scientific Unit Conversion

1998 ◽  
Vol 204 (Part_1_2) ◽  
pp. 265-265
Author(s):  
W. Schirmer
Keyword(s):  
Unit Conversion ◽  
Scientific Unit

Lifetime Evaluation of Oil-immersed Power Capacitor using Conversion Factor between Model Sample and Practical Equipment

2011 ◽  
Vol 131 (3) ◽  
pp. 329-334
Author(s):  
Masakazu Higashiyama ◽  
Ken-ichi Akiyama ◽  
Teruhiko Maeda ◽  
Shuhei Nakamura ◽  
Hiro Umemura ◽  
...  
Keyword(s):  
Conversion Factor ◽  
Model Sample

scholarly journals CO2 Intensities and Primary Energy Factors in the Future European Electricity System

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2165
Author(s):  
Sam Hamels
Keyword(s):  
Co2 Emissions ◽  
Energy Use ◽  
Conversion Factor ◽  
Unit Commitment ◽  
Primary Energy ◽  
High Temporal Resolution ◽  
The European Union ◽  
Electricity System ◽  
Energy Factors ◽  
Electrical Loads

The European Union strives for sharp reductions in both CO2 emissions as well as primary energy use. Electricity consuming technologies are becoming increasingly important in this context, due to the ongoing electrification of transport and heating services. To correctly evaluate these technologies, conversion factors are needed—namely CO2 intensities and primary energy factors (PEFs). However, this evaluation is hindered by the unavailability of a high-quality database of conversion factor values. Ideally, such a database has a broad geographical scope, a high temporal resolution and considers cross-country exchanges of electricity as well as future evolutions in the electricity mix. In this paper, a state-of-the-art unit commitment economic dispatch model of the European electricity system is developed and a flow-tracing technique is innovatively applied to future scenarios (2025–2040)—to generate such a database and make it publicly available. Important dynamics are revealed, including an overall decrease in conversion factor values as well as considerable temporal variability at both the seasonal and hourly level. Furthermore, the importance of taking into account imports and carefully considering the calculation methodology for PEFs are both confirmed. Future estimates of the CO2 emissions and primary energy use associated with individual electrical loads can be meaningfully improved by taking into account these dynamics.

scholarly journals Probabilistic Assessment of Roof Snow Load and the Calibration of Shape Coefficients in the Eurocodes

2021 ◽  
Vol 11 (7) ◽  
pp. 2984
Author(s):  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi
Keyword(s):  
Conversion Factor ◽  
Reference Value ◽  
Construction Site ◽  
Probability Of Exceedance ◽  
Snow Load ◽  
Shape Coefficient ◽  
Annual Probability ◽  
Wind Exposure ◽  
Design Values ◽  
One Year

In modern structural codes, the reference value of the snow load on roofs is commonly given as the product of the characteristic value of the ground snow load at the construction site multiplied by the shape coefficient. The shape coefficient is a conversion factor which depends on the roof geometry, its wind exposure, and its thermal properties. In the Eurocodes, the characteristic roof snow load is either defined as the value corresponding to an annual probability of exceedance of 0.02 or as a nominal value. In this paper, an improved methodology to evaluate the roof snow load characterized by a given probability of exceedance (e.g., p=0.02 in one year) is presented based on appropriate probability density functions for ground snow loads and shape coefficients, duly taking into account the influence of the roof’s geometry and its exposure to wind. In that context, the curves for the design values of the shape coefficients are provided as a function of the coefficient of variation (COVg) of the yearly maxima of the snow load on the ground expected at a given site, considering three relevant wind exposure conditions: sheltered or non-exposed, semi-sheltered or normal, and windswept or exposed. The design shape coefficients for flat and pitched roofs, obtained considering roof snow load measurements collected in Europe during the European Snow Load Research Project (ESLRP) and in Norway, are finally compared with the roof snow load provisions given in the relevant existing Eurocode EN1991-1-3:2003 and in the new version being developed (prEN1991-1-3:2020) for the “second generation” of the Eurocodes.

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