scholarly journals A Wet Gas Metering System Based on the Extended-Throat Venturi Tube

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2120
Author(s):  
Haobai Xue ◽  
Peining Yu ◽  
Maomao Zhang ◽  
Haifeng Zhang ◽  
Encheng Wang ◽  
...  
Keyword(s):  
Relative Error ◽  
Theoretical Models ◽  
Venturi Tube ◽  
Iteration Algorithm ◽  
Liquid Content ◽  
Wet Gas ◽  
Error Distributions ◽  
Relative Errors ◽  
Throat Section ◽  
The Relationship

Although the use of a classical Venturi tube for wet gas metering has been extensively studied in the literature, the use of an extended-throat Venturi (ETV) tube has rarely been reported since its first proposal by J. R. Fincke in 1999. The structure of an ETV is very simple, but due to the complexity of multiphase flow, its theoretical model has not been fully established yet. Therefore, in this paper theoretical models have been developed for the convergent and throat sections of an ETV, and the gradients of front and rear differential pressures are derived analytically. Several flowrate algorithms have been proposed and compared with the existing ones. Among them, the iteration algorithm is found to be the best. A reasonable explanation is provided for its performance. The relationship between the differential pressure gradient and the flowrate relative error is also studied, such that the relative error distributions varying with ETV measured flowrates can be derived. The gas flowrate error of ETV increases with the liquid content whilst the liquid flowrate error of ETV decreases with the liquid content, and the relative errors of liquid flowrate are generally 2 to 3 times larger than that of the gas flowrate. Finally, the ETV tends to be more accurate than the classical Venturi tube. The ETV can be designed more compact under the same signal intensity due to its significantly higher velocity in the throat section.

Study on the Key Factors of Wet Gas Metering Overreading in Standard Venturi Tube Base on DPM

2012 ◽  
Vol 220-223 ◽  
pp. 1693-1697 ◽  
Author(s):  
Ying Xu ◽  
Yi Zhao ◽  
Zheng Hai Long
Keyword(s):  
Froude Number ◽  
Relative Error ◽  
Venturi Tube ◽  
Experimental Results ◽  
Average Relative Error ◽  
Maximum Relative Error ◽  
Multiphase Model ◽  
Key Factors ◽  
Wet Gas

This article discusses how and why the wet gas metering overreading produce for a standard Venturi tube by analyzing the influence of the key parameters of X parameter, the Froude number and pressure. The adopted multiphase model is DPM. The results of simulation are compared with the experimental results of National Engineering Laboratory. The maximum relative error of the predicted overreading from simulation is 5.14% and the average relative error is less than 2.8%.

Application of pyrometer and standard sample to determine surface temperature of studied materials

2019 ◽  
pp. 9-13
Author(s):  
V.Ya. Mendeleyev ◽  
V.A. Petrov ◽  
A.V. Yashin ◽  
A.I. Vangonen ◽  
O.K. Taganov
Keyword(s):  
Composite Material ◽  
Surface Temperature ◽  
Relative Error ◽  
Wavelength Range ◽  
Standard Sample ◽  
A Priori ◽  
Temperature Changes ◽  
Surface Temperatures ◽  
Relative Errors ◽  
Normal Emissivity

Determining the surface temperature of materials with unknown emissivity is studied. A method for determining the surface temperature using a standard sample of average spectral normal emissivity in the wavelength range of 1,65–1,80 μm and an industrially produced Metis M322 pyrometer operating in the same wavelength range. The surface temperature of studied samples of the composite material and platinum was determined experimentally from the temperature of a standard sample located on the studied surfaces. The relative error in determining the surface temperature of the studied materials, introduced by the proposed method, was calculated taking into account the temperatures of the platinum and the composite material, determined from the temperature of the standard sample located on the studied surfaces, and from the temperature of the studied surfaces in the absence of the standard sample. The relative errors thus obtained did not exceed 1,7 % for the composite material and 0,5% for the platinum at surface temperatures of about 973 K. It was also found that: the inaccuracy of a priori data on the emissivity of the standard sample in the range (–0,01; 0,01) relative to the average emissivity increases the relative error in determining the temperature of the composite material by 0,68 %, and the installation of a standard sample on the studied materials leads to temperature changes on the periphery of the surface not exceeding 0,47 % for composite material and 0,05 % for platinum.

scholarly journals A ΔSOC-based equalization strategy applied to industry

2020 ◽  
Author(s):  
Maonan Wang ◽  
Chun Chang ◽  
Feng Ji
Keyword(s):  
Open Circuit ◽  
Battery Pack ◽  
Battery Management System ◽  
Battery Management ◽  
Battery Cell ◽  
New Strategy ◽  
The Difference ◽  
Relative Errors ◽  
The Relationship ◽  
Battery Cells

Abstract The voltage-based equalization strategy is widely used in the industry because the voltage (U) of the battery cell is very easy to obtain, but it is difficult to provide an accurate parameter for the battery management system (BMS). This study proposes a new equalization strategy, which is based on the difference between the state of charge (SOC) of any two battery cells in the battery pack, that is, a ΔSOC-based equalization strategy. The new strategy is not only as simple as the voltage-based equalization strategy, but it can also provide an accurate parameter for the BMS. Simply put, using the relationship between the open circuit voltage and the SOC of the battery pack, the proposed strategy can convert the difference between the voltage of the battery cells into ΔSOC, which renders a good performance. Additionally, the required parameters are all from the BMS, and no additional calculation is required, which makes the strategy as simple as the voltage-based balancing strategy. The four experiments show that the relative errors of ΔSOC estimated by the ΔSOC-based equalization strategy are 0.37%, 0.39%, 0.1% and 0.17%, and thereby demonstrate that the ΔSOC-based equalization strategy proposed in this study shows promise in replacing the voltage-based equalization strategy within the industry to obtain better performance.

ANALYSIS OF THE ERROR IN DETERMINING THE EQUIVALENT SIZE OF A DEFECT BY THE STANDARDLESS METHOD DURING ULTRASONIC TESTING

2021 ◽  
pp. 50-57
Author(s):  
A. N. Kireev ◽  
M. A. Kireeva
Keyword(s):  
Relative Error ◽  
High Reliability ◽  
Ultrasonic Method ◽  
Experimental Studies ◽  
Standard Samples ◽  
Defect Identification ◽  
Identification Method ◽  
Maximum Value ◽  
Software Product ◽  
The Relationship

The article provides a review and analysis of the defect identification method for determining the size of discontinuities when diagnosing various machine parts and units by the manual ultrasonic method. This method makes it possible to determine the equivalent size of discontinuities of various types without using standard samples of an enterprise: point planar and volumetric; extended planar and volumetric. The method is based on the use of the relationship between the amplitude and time characteristics of the echo signal from the discontinuity and the backside signal in the object being diagnosed and the equivalent size of the discontinuity. The article presents the mathematical apparatus for the implementation of this method. Also presented is a software product that allows you to automate calculations when using this defect identification method. The article contains experimental studies of the method for determining the equivalent dimensions of discontinuities of various types, which have shown its high reliability. The maximum value of the relative error in determining the equivalent size of a point planar discontinuity was 2.867 %. The maximum value of the relative error in determining the equivalent size of a point volumetric discontinuity was 1.986 %. The maximum value of the relative error in determining the transverse equivalent size of an extended planar discontinuity was 0.667 %. The maximum value of the relative error in determining the transverse equivalent size of an extended volumetric discontinuity was 1.95 %.

An Ethos of Inclusion for Global Nursing Practice

2021 ◽  
Vol 35 (1) ◽  
pp. 3-6
Author(s):  
Michele J. Upvall
Keyword(s):  
Nursing Practice ◽  
Theoretical Models ◽  
Codes Of Ethics ◽  
The Relationship

The Year of the Nurse and Midwife, 2020, is an opportunity for global nurses to realize the ethos of inclusion for transformative global nursing partnerships. Including all partners in developing and maintaining the relationship provides the foundation for bidirectionality whereby all partners learn and grow personally and professionally from each other. Guidelines, theoretical models, and Codes of Ethics are suggested for applying an ethos of inclusion in all global nursing partnerships.

scholarly journals Which hand is mine? Discriminating body ownership perception in a two-alternative forced choice task

2020 ◽  
Author(s):  
Marie Chancel ◽  
H. Henrik Ehrsson
Keyword(s):  
Conscious Experience ◽  
Theoretical Models ◽  
Forced Choice ◽  
Body Ownership ◽  
Sensory Modalities ◽  
Forced Choice Task ◽  
Temporal And Spatial ◽  
The Relationship ◽  
Spatial Congruence ◽  
Perception Action

The experience of one’s body as one’s own is referred to as the sense of body ownership. This central part of human conscious experience determines the boundary between the self and the external environment, a crucial distinction in perception, action, and cognition. Although body ownership is known to involve the integration of signals from multiple sensory modalities, including vision, touch and proprioception, little is known about the principles that determine this integration process, and the relationship between body ownership and perception is unclear. These uncertainties stem from the lack of a sensitive and rigorous method to quantify body ownership. Here, we describe a two-alternative forced choice discrimination task that allows precise and direct measurement of body ownership as participants decide which of two rubber hands feels more like their own in a version of the rubber hand illusion. In two experiments, we show that the temporal and spatial congruence principles of multisensory stimulation, which determine ownership discrimination, impose tighter constraints than previously thought and that texture congruence constitutes an additional principle; these findings are compatible with theoretical models of multisensory integration. Taken together, our results suggest that body ownership constitutes a genuine perceptual multisensory phenomenon that can be quantified with psychophysics in discrimination experiments.

scholarly journals CD8 coreceptor-mediated focusing can reorder the agonist hierarchy of peptide ligands recognized via the T cell receptor

2020 ◽  
Author(s):  
Mathew Clement ◽  
Lea Knezevic ◽  
Tamsin Dockree ◽  
James E. McLaren ◽  
Kristin Ladell ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Theoretical Models ◽  
Cell Receptor ◽  
Dissociation Rate ◽  
Peptide Ligands ◽  
Controlled System ◽  
Peptide Antigens ◽  
Histocompatibility Complex ◽  
The Relationship

ABSTRACTCD8+ T cells are inherently cross-reactive and recognize numerous peptide antigens in the context of a given major histocompatibility complex class I (MHCI) molecule via the clonotypically expressed T cell receptor (TCR). The lineally expressed coreceptor CD8 interacts coordinately with MHCI at a distinct and largely invariant site to slow the TCR/peptide-MHCI (pMHCI) dissociation rate and enhance antigen sensitivity. However, this biological effect is not necessarily uniform, and theoretical models suggest that antigen sensitivity can be modulated in a differential manner by CD8. We used an intrinsically controlled system to determine how the relationship between the TCR/pMHCI interaction and the pMHCI/CD8 interaction affects the functional sensitivity of antigen recognition. Our data show that modulation of the pMHCI/CD8 interaction can reorder the agonist hierarchy of peptide ligands across a spectrum of affinities for the TCR.SIGNIFICANCESufficient immune coverage of the peptide universe within a finite host requires highly degenerate T cell receptors (TCRs). However, this inherent need for antigen cross-recognition is associated with a high risk of autoimmunity, which can only be mitigated by a process of adaptable specificity. We describe a mechanism that resolves this conundrum by allowing individual clonotypes to focus on specific peptide ligands without alterations to the structure of the TCR.

scholarly journals Do Stress Trajectories Predict Mortality in Older Men? Longitudinal Findings from the VA Normative Aging Study

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Carolyn M. Aldwin ◽  
Nuoo-Ting Molitor ◽  
Avron Spiro ◽  
Michael R. Levenson ◽  
John Molitor ◽  
...  
Keyword(s):  
Allostatic Load ◽  
Stressful Life Events ◽  
High Stress ◽  
Theoretical Models ◽  
Growth Mixture Model ◽  
Growth Mixture ◽  
Aging Study ◽  
Health Related ◽  
The Relationship

We examined long-term patterns of stressful life events (SLE) and their impact on mortality contrasting two theoretical models: allostatic load (linear relationship) and hormesis (inverted U relationship) in 1443 NAS men (aged 41–87 in 1985;M= 60.30, SD = 7.3) with at least two reports of SLEs over 18 years (total observations = 7,634). Using a zero-inflated Poisson growth mixture model, we identified four patterns of SLE trajectories, three showing linear decreases over time with low, medium, and high intercepts, respectively, and one an inverted U, peaking at age 70. Repeating the analysis omitting two health-related SLEs yielded only the first three linear patterns. Compared to the low-stress group, both the moderate and the high-stress groups showed excess mortality, controlling for demographics and health behavior habits, HRs = 1.42 and 1.37,ps<.01and<.05. The relationship between stress trajectories and mortality was complex and not easily explained by either theoretical model.

Precision of Earthwork Computation by Grid

2011 ◽  
Vol 243-249 ◽  
pp. 5864-5868
Author(s):  
Hong Hu Wei ◽  
Yan Bao
Keyword(s):  
Theoretical Calculation ◽  
Relative Error ◽  
Grid Method ◽  
Theoretical Models ◽  
Basic Relationship ◽  
Terrain Parameters

Based on theoretical models,the accuracy is analyzed to earthwork calculation in grid method under different terrain rolling rates, different grid widths.And the basic relationship between relative error of theoretical calculation and grid and terrain parameters is obtained, which can be used for evaluation of practical earthwork calculation.

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