scholarly journals Dual-phase flow in two-layer porous media: a radial composite Laplace domain approximation

2021 ◽  
Author(s):  
Ana Luiza Mastbaum ◽  
Ayla Bosso de Souza ◽  
Jéssica Lailla Ferreira Bittencourt Neto ◽  
Renan Vieira Bela ◽  
Abelardo Borges Barreto
Keyword(s):  
Front Propagation ◽  
Sensitivity Study ◽  
Pressure Derivative ◽  
Laplace Domain ◽  
Injection Flow ◽  
Flow Displacement ◽  
Real Domain ◽  
Flow Simulator ◽  
Interpretation Method ◽  
Good Agreement

AbstractThe main purpose of this work is to present an interpretation method for injectivity test in a two-layer reservoir that can be extended to a multilayer approach, based on new analytical solutions to the well pressure response. The developed formulation uses a radially composite reservoir approach and considers that the water front propagation may be approximated by a piston-like flow displacement. The reservoir is assumed to be laterally infinite and properties such as permeability and porosity may be different in each layer. The solutions were developed in the Laplace domain and then inverted to real domain using the Stehfest Algorithm. The proposed formulation was then validated by comparison with a numerical flow simulator. Results showed a good agreement between the numerical simulator and the analytical model. Also, a sensitivity study was done by comparing the results of different scenarios varying oil viscosities and injection flow rate to assess how these properties affect the pressure and pressure derivative profiles.

scholarly journals SENSITIVE ANALYSIS OF A COAL COMBUSTION MODEL ON A DROP TUBE FURNACE

2013 ◽  
Vol 12 (2) ◽  
pp. 51
Author(s):  
L. Zimmer ◽  
F. M. Pereira ◽  
P. S. Schneider
Keyword(s):  
Coal Combustion ◽  
Reference Model ◽  
Sensitivity Study ◽  
Tube Furnace ◽  
Combustion Model ◽  
Drop Tube ◽  
Drop Tube Furnace ◽  
Flow Heat ◽  
Working Parameters ◽  
Good Agreement

In the present work a one-dimensional model for coal combustion in a Drop Tube Furnace (DTF) is developed. The equations that characterize the flow, heat transfer phenomena and coal combustion reactions are programmed in a FORTRAN90 language code. The results are compared with a reference model and experimental data, showing good agreement. A sensitivity study is performed to understand the behavior of coal combustion due to changes of some working parameters of the DTF. From the variation of the oxygen concentration, working temperature and input flow rates the response of the coal combustion in terms of unburned fraction can be obtained.

scholarly journals Comparison of GPM Core Observatory and Ground-Based Radar Retrieval of Mass-Weighted Mean Raindrop Diameter at Midlatitude

2018 ◽  
Vol 19 (10) ◽  
pp. 1583-1598 ◽  
Author(s):  
Leo Pio D’Adderio ◽  
Gianfranco Vulpiani ◽  
Federico Porcù ◽  
Ali Tokay ◽  
Robert Meneghini
Keyword(s):  
High Sensitivity ◽  
Sensitivity Study ◽  
Three Dimensions ◽  
Convective Precipitation ◽  
Precipitation Pattern ◽  
Dual Frequency ◽  
Weighted Mean ◽  
Raindrop Size Distribution ◽  
Two Parameters ◽  
Good Agreement

Abstract One of the main goals of the National Aeronautics and Space Administration (NASA) Global Precipitation Measurement (GPM) mission is to retrieve parameters of the raindrop size distribution (DSD) globally. As a standard product of the Dual-Frequency Precipitation Radar (DPR) on board the GPM Core Observatory satellite, the mass-weighted mean diameter Dm and the normalized intercept parameter Nw are estimated in three dimensions at the resolution of the radar. These are two parameters of the three-parameter gamma model DSD adopted by the GPM algorithms. This study investigates the accuracy of the Dm retrieval through a comparative study of C-band ground radars (GRs) and GPM products over Italy. The reliability of the ground reference is tested by using two different approaches to estimate Dm. The results show good agreement between the ground-based and spaceborne-derived Dm, with an absolute bias being generally lower than 0.5 mm over land in stratiform precipitation for the DPR algorithm and the combined DPR–GMI algorithm. For the DPR–GMI algorithm, the good agreement extends to convective precipitation as well. Estimates of Dm from the DPR high-sensitivity (HS) Ka-band data show slightly worse results. A sensitivity study indicates that the accuracy of the Dm estimation is independent of the height above surface (not shown) and the distance from the ground radar. On the other hand, a nonuniform precipitation pattern (interpreted both as high variability and as a patchy spatial distribution) within the DPR footprint is usually associated with a significant error in the DPR-derived estimate of Dm.

scholarly journals Estimation of Antarctic ozone loss from ground-based total column measurements

2010 ◽  
Vol 10 (14) ◽  
pp. 6569-6581 ◽  
Author(s):  
J. Kuttippurath ◽  
F. Goutail ◽  
J.-P. Pommereau ◽  
F. Lefèvre ◽  
H. K. Roscoe ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Sensitivity Study ◽  
Satellite Measurements ◽  
Macquarie Island ◽  
Ozone Loss ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Ozone Column ◽  
Total Column ◽  
Good Agreement

Abstract. The passive tracer method is used to estimate ozone loss from ground-based measurements in the Antarctic. A sensitivity study shows that the ozone depletion can be estimated within an accuracy of ~4%. The method is then applied to the ground-based observations from Arrival Heights, Belgrano, Concordia, Dumont d'Urville, Faraday, Halley, Marambio, Neumayer, Rothera, South Pole, Syowa, and Zhongshan for the diagnosis of ozone loss in the Antarctic. On average, the ten-day boxcar average of the vortex mean ozone column loss deduced from the ground-based stations was about 55±5% in 2005–2009. The ozone loss computed from the ground-based measurements is in very good agreement with those derived from satellite measurements (OMI and SCIAMACHY) and model simulations (REPROBUS and SLIMCAT), where the differences are within ±3–5%. The historical ground-based total ozone observations in October show that the depletion started in the late 1970s, reached a maximum in the early 1990s and stabilised afterwards due to saturation. There is no indication of ozone recovery yet. At southern mid-latitudes, a reduction of 20–50% is observed for a few days in October–November at the newly installed Rio Gallegos station. Similar depletion of ozone is also observed episodically during the vortex overpasses at Kerguelen in October–November and at Macquarie Island in July–August of the recent winters. This illustrates the significance of measurements at the edges of Antarctica.

Computational Approach of the Cortical Bone Mechanical Behavior Based on an Elastic Viscoplastic Damageable Constitutive Model

2020 ◽  
Vol 12 (07) ◽  
pp. 2050081
Author(s):  
Tesnim Kraiem ◽  
Abdelwahed Barkaoui ◽  
Tarek Merzouki ◽  
Moez Chafra
Keyword(s):  
Mechanical Behavior ◽  
Bone Quality ◽  
Damage Evolution ◽  
Sensitivity Study ◽  
Computational Approach ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Non Invasive ◽  
Applied Loading ◽  
Good Agreement

Bone mechanical behavior varies according to the mechanical loading to which it is subjected, and its response effectiveness mainly depends on its quality. Thus, measuring the indicators controlling the bone quality is required to assess its strength. Indeed, the Finite Element Method (FEM) provides a non-invasive tool to interpret bone quality. Therefore, this work coupled the FEM with a micromechanical law, aiming to provide an exhaustive description of the human bone mechanical behavior. Anisotropy, viscoplasticity and damage were introduced in the material behavior law and the damage evolution was plotted based on the applied loading. Then a sensitivity study was conducted to evaluate the effects of viscoplasticity and damage parameters on bone behavior. The obtained numerical results were in a good agreement with the previously reported experimental data and allowed to distinguish key parameters from non-significant ones. This new computational model provided a better understanding of the main parameters affecting bone behavior.

scholarly journals Microstructure Adjustment of Spherical Micro-samples for High-Throughput Analysis Using a Drop-on-Demand Droplet Generator

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3769 ◽  
Author(s):  
Moqadam ◽  
Mädler ◽  
Ellendt
Keyword(s):  
High Throughput ◽  
Metal Droplet ◽  
Sensitivity Study ◽  
Droplet Generator ◽  
High Throughput Analysis ◽  
Drop On Demand ◽  
Critical Process Parameters ◽  
Critical Process ◽  
Good Agreement ◽  
Cooling Model

: High-throughput methods for the development of structural materials require samples which are comparable in geometric dimensions and microstructure. Molten metal droplet generators produce thousands of droplets and microspheres from specific alloys with very good reproducibility. In this study, droplet generation experiments were conducted with two alloys and their microstructure was analyzed regarding secondary dendrite arm spacing (SDAS) in order to determine cooling rates during solidification. A droplet cooling model was developed, and predictions showed good agreement with the experimental data. Finally, a sensitivity study was conducted using the validated model to identify critical process parameters which have great impact on the resulting microstructure and need to be well-controlled to achieve the desired reproducibility in microstructure.

First-Principles Calculations of the Structural, Electronic, Optical and Mechanical Properties of CdS, CdSe and CdTe

2013 ◽  
Vol 665 ◽  
pp. 302-306 ◽  
Author(s):  
Sheetal Sharma ◽  
Ajay Singh Verma
Keyword(s):  
Experimental Data ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Zinc Blende ◽  
Optical And Mechanical Properties ◽  
Good Agreement

The structural, electronic, optical and elastic properties of zinc-blende compounds (CdX, X = S, Se and Te), were studied using full-potential augmented plane wave plus local orbitals method (FP-LAPW+ lo) within density functional theory, using generalized gradient approximation (GGA). Geometrical optimization of the unit cell (lattice constant, bulk modulus and its pressure derivative) is in good agreement with experimental data. Results for band structures, density of states, and elastic constants (C11, C12 and C44) are presented. We also report our results on optical properties like the complex dielectric functions and the refractive index (n) of these compounds. Our results are in reasonable agreement with the available theoretical and experimental data.

A High Order, Lumped Parameter, Jet Dynamic Model for the Frequency Response of Laminar Proportional Amplifiers

1981 ◽  
Vol 103 (4) ◽  
pp. 317-323
Author(s):  
T. M. Drzewiecki
Keyword(s):  
Frequency Response ◽  
Dynamic Model ◽  
Low Frequency ◽  
Electrical Circuit ◽  
High Order ◽  
Step Response ◽  
Average Particle ◽  
Laplace Domain ◽  
Lumped Parameter ◽  
Good Agreement

This paper presents a high-order, lumped parameter, jet-dynamic model for laminar proportional amplifiers (LPA’s). The governing equations for the lumped-parameter representation of the flow regimes found in the input of an LPA are derived in the Laplace domain, and an equivalent electrical circuit is obtained. The input governs the overall response of the LPA and may be modeled in its simplest form by five reactive components. The transmission of the signal from input to output is delayed by a transport time (determined by observation of flow visualization of a step response) equal to twice the average particle transit time. A pressure difference is then developed at the splitter that is proportional to the loading and the vent conditions. This signal is acoustically fed back to the control region of the jet, augmenting jet deflection when in phase. The vent inductance is found to have a significant influence on the low-frequency gain. Resonant regions determined by this model correspond closely to edgetone eigenfrequencies reported in the literature. Experimental data have shown good agreement with theory for the amplitude frequency response of LPA’s and excellent agreement for the phase shift. An engineering guide developed for the bandpass characteristics of LPA’s indicates that operating bandwidths of up to 14 kHz can be expected for amplifiers with a nozzle width of 0.25 mm, and ultrasonic operation appears feasible with devices having nozzle widths as large as 0.1 mm.

scholarly journals First space-borne measurements of methanol inside aged tropical biomass burning plumes using the ACE-FTS instrument

2006 ◽  
Vol 6 (3) ◽  
pp. 3945-3963 ◽  
Author(s):  
G. Dufour ◽  
C. D. Boone ◽  
C. P. Rinsland ◽  
P. F. Bernath
Keyword(s):  
Biomass Burning ◽  
Secondary Production ◽  
Sensitivity Study ◽  
Strongly Correlated ◽  
Air Masses ◽  
Mixing Ratios ◽  
Fire Plumes ◽  
Correlation Plot ◽  
Infrared Spectrometer ◽  
Good Agreement

Abstract. First measurements from space of upper tropospheric and lower stratospheric methanol profiles within aged fire plumes are reported. Elevated levels of methanol at 0–45° S from 30 September to 3 November 2004 have been measured by the high resolution infrared spectrometer ACE-FTS onboard the SCISAT satellite. Methanol volume mixing ratios higher than 4000 pptv are detected and are strongly correlated with other fire products such as CO, C2H6, and HCN. A sensitivity study of the methanol retrieval, accounting for random and systematic contributions, shows that the retrieved methanol profile is reliable from 8.5 to 16.5 km, with an accuracy of about 20% for measurements inside polluted air masses. The upper tropospheric enhancement ratio of methanol with respect to CO is estimated from the correlation plot between methanol and CO for aged tropical biomass burning plumes. This ratio is in good agreement with the ratio measured in the free troposphere (up to 12 km) by recent aircraft studies and does not suggest any secondary production of methanol by oxidation in aged biomass burning plumes.

Lubrication Analysis of a Rolling Piston Rotary Compressor: Part 2: Experimental Validation and Results

1994 ◽  
Vol 208 (2) ◽  
pp. 95-104
Author(s):  
S K Padhy
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Experimental Validation ◽  
Sensitivity Study ◽  
Rotary Compressor ◽  
Oil Flow ◽  
Different Dimensions ◽  
Rolling Piston ◽  
The Mathematical Model ◽  
Good Agreement

In this paper the experiments conducted for the measurement of oil flow in the rotary compressor are described. The experimental data are compared against the theoretical prediction from the mathematical model developed (1) and a good agreement is found. In addition, experimental data from previously published literature are also used to verify the mathematical model. A sensitivity study is carried out to predict the behaviour of the rotary compressor for the oil flow at different conditions and with different dimensions.

On the Dynamics of a Rotary Compressor: Part 2 — Experimental Validation and Sensitivity Analysis

1993 ◽  
Author(s):  
Sisir K. Padhy
Keyword(s):  
Experimental Validation ◽  
Sensitivity Study ◽  
Rotary Compressor ◽  
Dynamics Model ◽  
The Coefficient Of Friction ◽  
The Moment ◽  
Discharge Pressure ◽  
Roller Radius ◽  
Theoretical Results ◽  
Good Agreement

Abstract This paper describes the experimental validation of the rotary compressor dynamics model [1]. Roller velocity is measured using video technology and a very good agreement is found with the theoretical results. A sensitivity study using different variables that affect the compressor dynamics is also carried out. It is found that the coefficient of friction at the vane and roller plays an important role in roller velocity. The dynamics of roller is influenced by the clearances, the roller radius, the vane radius, eccentricity of the shaft, the frictional behavior between the roller ends and the bearing plates, the discharge pressure of the compressor as well as the moment of inertia of roller.

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