scholarly journals Sensitivity of convective rainfall to the adjustment parameters in the Betts-Miller scheme

MAUSAM ◽  
2021 ◽  
Vol 47 (4) ◽  
pp. 395-402
Author(s):  
S.S. VAIDYA ◽  
S. S. SINGH
Keyword(s):  
Numerical Experiments ◽  
Saturation Pressure ◽  
Cumulus Convection ◽  
Convective Rainfall ◽  
Convective Rain ◽  
Rain Fall ◽  
The Impact

ABSTACT. Three numerical experiments are carried out to study the sensitivity of the convective rain fall to the adjustment parameters used in the Betts-Miller scheme of cumulus convection. The results of the numerical experiments indicate that the convective rainfall has considerable sensitivity to saturation pressure departure value (S) whereas the impact of stability weight (W) on the convective rainfall is marginal. The limiting S values are found to produce drying of the column.  

scholarly journals Comprehensive Analytical Modelling of an Absolute pH Sensor

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5190
Author(s):  
Cristina Medina-Bailon ◽  
Naveen Kumar ◽  
Rakshita Pritam Singh Dhar ◽  
Ilina Todorova ◽  
Damien Lenoble ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Numerical Experiments ◽  
Ph Sensor ◽  
Hafnium Dioxide ◽  
Matlab Code ◽  
Oxide Degradation ◽  
Depletion Width ◽  
Ion Activity ◽  
The Absolute ◽  
The Impact

In this work, we present a comprehensive analytical model and results for an absolute pH sensor. Our work aims to address critical scientific issues such as: (1) the impact of the oxide degradation (sensing interface deterioration) on the sensor’s performance and (2) how to achieve a measurement of the absolute ion activity. The methods described here are based on analytical equations which we have derived and implemented in MATLAB code to execute the numerical experiments. The main results of our work show that the depletion width of the sensors is strongly influenced by the pH and the variations of the same depletion width as a function of the pH is significantly smaller for hafnium dioxide in comparison to silicon dioxide. We propose a method to determine the absolute pH using a dual capacitance system, which can be mapped to unequivocally determine the acidity. We compare the impact of degradation in two materials: SiO2 and HfO2, and we illustrate the acidity determination with the functioning of a dual device with SiO2.

Machine Learning and Artificial Intelligence Provides Wolfcamp Completion Design Insight

2021 ◽  
Author(s):  
Robert Shelley ◽  
Oladapo Oduba ◽  
Howard Melcher
Keyword(s):  
Machine Learning ◽  
Water Saturation ◽  
Saturation Pressure ◽  
Ann Model ◽  
Permian Basin ◽  
Treatment Rate ◽  
Feed Forward Neural Network ◽  
Well Production ◽  
Reservoir Type ◽  
The Impact

Abstract The subject of this paper is the application of a unique machine learning approach to the evaluation of Wolfcamp B completions. A database consisting of Reservoir, Completion, Frac and Production information from 301 Multi-Fractured Horizontal Wolfcamp B Completions was assembled. These completions were from a 10-County area located in the Texas portion of the Permian Basin. Within this database there is a wide variation in completion design from many operators; lateral lengths ranging from a low of about 4,000 ft to a high of almost 15,000 ft, proppant intensities from 500 to 4,000 lb/ft and frac stage spacing from 59 to 769 ft. Two independent self-organizing data mappings (SOM) were performed; the first on completion and frac stage parameters, the second on reservoir and geology. Characteristics for wells assigned to each SOM bin were determined. These two mappings were then combined into a reservoir type vs completion type matrix. This type of approach is intended to remove systemactic errors in measuement, bias and inconsistencies in the database so that more realistic assessments about well performance can be made. Production for completion and reservoir type combinations were determined. As a final step, a feed forward neural network (ANN) model was developed from the mapped data. This model was used to estimate Wolfcamp B production and economics for completion and frac designs. In the performance of this project, it became apparent that the incorporation of reservoir data was essential to understanding the impact of completion and frac design on multi-fractured horizontal Wolfcamp B well production and economic performance. As we would expect, wells with the most permeability, higher pore pressure, effective porosity and lower water saturation have the greatest potential for hydrocarbon production. The most effective completion types have an optimum combination of proppant intensity, fluid intensity, treatment rate, frac stage spacing and perforation clustering. This paper will be of interest to anyone optimizing hydraulically fractured Wolfcamp B completion design or evaluating Permian Basin prospects. Also, of interest is the impact of reservoir and completion characteristics such as permeability, porosity, water saturation, pressure, offset well production, proppant intensity, fluid intensity, frac stage spacing and lateral length on well production and economics. The methodology used to evaluate the impact of reservoir and completion parameters for this Wolfcamp project is unique and novel. In addition, compared to other methodologies, it is low cost and fast. And though the focus of this paper is on the Wolfcamp B Formation in the Midland Basin, this approach and workflow can be applied to any formation in any Basin, provided sufficient data is available.

scholarly journals The impact of rheological uncertainty on dynamic topography predictions

Solid Earth ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 2167-2178 ◽  
Author(s):  
Ömer F. Bodur ◽  
Patrice F. Rey
Keyword(s):  
Mantle Convection ◽  
Numerical Experiments ◽  
Mantle Flow ◽  
Dynamic Topography ◽  
Density Anomaly ◽  
Low Viscosity ◽  
Local Reduction ◽  
Dynamic Components ◽  
Mantle Rheology ◽  
The Impact

Abstract. Much effort is being made to extract the dynamic components of the Earth's topography driven by density heterogeneities in the mantle. Seismically mapped density anomalies have been used as an input into mantle convection models to predict the present-day mantle flow and stresses applied on the Earth's surface, resulting in dynamic topography. However, mantle convection models give dynamic topography amplitudes generally larger by a factor of ∼2, depending on the flow wavelength, compared to dynamic topography amplitudes obtained by removing the isostatically compensated topography from the Earth's topography. In this paper, we use 3-D numerical experiments to evaluate the extent to which the dynamic topography depends on mantle rheology. We calculate the amplitude of instantaneous dynamic topography induced by the motion of a small spherical density anomaly (∼100 km radius) embedded into the mantle. Our experiments show that, at relatively short wavelengths (<1000 km), the amplitude of dynamic topography, in the case of non-Newtonian mantle rheology, is reduced by a factor of ∼2 compared to isoviscous rheology. This is explained by the formation of a low-viscosity channel beneath the lithosphere and a decrease in thickness of the mechanical lithosphere due to induced local reduction in viscosity. The latter is often neglected in global mantle convection models. Although our results are strictly valid for flow wavelengths less than 1000 km, we note that in non-Newtonian rheology all wavelengths are coupled, and the dynamic topography at long wavelengths will be influenced.

scholarly journals Effect of moisture stress on leaf protein, proline, peroxidise activity and yield in released and pre-released genotypes of groundnut (Arachis hypogaea L.)

2020 ◽  
Vol 16 (2) ◽  
pp. 260-264
Author(s):  
H.Y. Patil ◽  
Pooja ◽  
V.P. Chimmad
Keyword(s):  
Enzyme Activity ◽  
Co2 Concentration ◽  
Moisture Stress ◽  
Leaf Protein ◽  
Growth Stages ◽  
Arachis Hypogaea L ◽  
Moisture Deficit ◽  
Peroxidase Enzyme ◽  
Rain Fall ◽  
The Impact

The performance of crops need to be assessed for their production under erratic rain fall pattern, increased temperatures, and enhanced atmospheric CO2 concentration. In the present study groundnut was chosen as test crop and selected genotypes [four released (GPBD-4, G2-52, Dh-86 and TMV-2) and four pre-released (Dh-245, Dh-232, Dh-256 and Dh-257)] were studied to quantify the impact of moisture deficit stress at critical growth stages i.e., 40 to 80 DAS and 80 DAS to harvest. Leaf protein and proline increases in tolerant genotypes at higher moisture stress levels than susceptible genotypes as they acts as osmolytes and maintains the turgidity of the cell and hence, checks the water loss and peroxidase enzyme activity which in turn scavenges ROS produced due to stress as a result there was reduction in yield. The genotypes, GPBD-4, Dh-257 and Dh-256 recorded higher per cent increase in leaf soluble protein, leaf proline and peroxidase enzyme activity at all the stages. Increase was higher at 80 DAS to harvest stressed plants than 40 to 80 DAS stressed plants.

scholarly journals ENHANCED MASS LOSS RATES IN RED SUPERGIANTS AND THEIR IMPACT ON THE CIRCUMSTELLAR MEDIUM

2019 ◽  
Vol 55 (2) ◽  
pp. 161-175
Author(s):  
L. Hernández-Cervantes ◽  
B. Pérez-Rendón ◽  
A. Santillán ◽  
G. García-Segura ◽  
C. Rodríguez-Ibarra
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Gas Dynamics ◽  
Numerical Experiments ◽  
Evolutionary Models ◽  
Solar Composition ◽  
Red Supergiants ◽  
The Impact ◽  
Circumstellar Medium ◽  
Loss Rates

In this work, we present models of massive stars between 15 and 23 M⊙ , with enhanced mass loss rates during the red supergiant phase. Our aim is to explore the impact of extreme red supergiant mass-loss on stellar evolution and on their circumstellar medium. We computed a set of numerical experiments, on the evolution of single stars with initial masses of 15, 18, 20 and, 23 M⊙ , and solar composition (Z = 0.014), using the numerical stellar code BEC. From these evolutionary models, we obtained time-dependent stellar wind parameters, that were used explicitly as inner boundary conditions in the hydrodynamical code ZEUS-3D, which simulates the gas dynamics in the circumstellar medium (CSM), thus coupling the stellar evolution to the dynamics of the CSM. We found that stars with extreme mass loss in the RSG phase behave as a larger mass stars.

Metaheuristic- and Statistical-Based Sampling in Optimization

2018 ◽  
pp. 84-104
Author(s):  
Yoel Tenne
Keyword(s):  
Computer Simulations ◽  
Real World ◽  
Computational Intelligence ◽  
Numerical Experiments ◽  
Strong Impact ◽  
Initial Sample ◽  
Modern Engineering ◽  
Computationally Intensive ◽  
The Impact ◽  
Optimization Search

Modern engineering often uses computer simulations as a partial substitute to real-world experiments. As such simulations are often computationally intensive, metamodels, which are numerical approximations of the simulation, are often used. Optimization frameworks which use metamodels require an initial sample of points to initiate the main optimization process. Two main approaches for generating the initial sample are the ‘design of experiments' method which is statistically based, and the more recent metaheuristic-based sampling which uses a metaheuristic or a computational intelligence algorithm. Since the initial sample can have a strong impact on the overall optimization search and since the two sampling approaches operate based only widely different mechanisms this study analyzes the impact of these two approaches on the overall search effectiveness in an extensive set of numerical experiments which covers a wide variety of scenarios. A detailed analysis is then presented which highlights which method was the most beneficial to the search depending on the problem settings.

scholarly journals Planet migration and magnetic torques

2015 ◽  
Vol 11 (A29A) ◽  
pp. 14-18
Author(s):  
A. Strugarek ◽  
A. S. Brun ◽  
S. P. Matt ◽  
V. Reville
Keyword(s):  
Numerical Experiments ◽  
Three Dimensional ◽  
Magnetic Star ◽  
Magnetic Topology ◽  
Global Models ◽  
Planet Migration ◽  
Order Of Magnitude ◽  
Ideal Magnetohydrodynamic ◽  
The Impact ◽  
The Ideal

AbstractThe possibility that magnetic torques may participate in close-in planet migration has recently been postulated. We develop three dimensional global models of magnetic star-planet interaction under the ideal magnetohydrodynamic (MHD) approximation to explore the impact of magnetic topology on the development of magnetic torques. We conduct twin numerical experiments in which only the magnetic topology of the interaction is altered. We find that magnetic torques can vary by roughly an order of magnitude when varying the magnetic topology from an aligned case to an anti-aligned case. Provided that the stellar magnetic field is strong enough, we find that magnetic migration time scales can be as fast as ~100 Myr. Hence, our model supports the idea that magnetic torques may participate in planet migration for some close-in star-planet systems.

scholarly journals The Impact of Management Fees on the Pricing of Variable Annuity Guarantees

Risks ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 103
Author(s):  
Jin Sun ◽  
Pavel Shevchenko ◽  
Man Fung
Keyword(s):  
Numerical Experiments ◽  
Downside Risk ◽  
Equity Market ◽  
Retirement Income ◽  
Variable Annuities ◽  
Management Fees ◽  
Market Friction ◽  
Market Management ◽  
Retirement Fund ◽  
The Impact

Variable annuities, as a class of retirement income products, allow equity market exposure for a policyholder’s retirement fund with optional guarantees to limit the downside risk of the market. Management fees andguarantee insurance fees are charged respectively for the market exposure and for the protection from the downside risk. We investigate the pricing of variable annuity guarantees under optimal withdrawal strategies when management fees are present. We consider from both policyholder’s and insurer’s perspectives optimal withdrawal strategies and calculate the respective fair insurance fees. We reveal a discrepancy where the fees from the insurer’s perspective can be significantly higher due to the management fees serving as a form of market friction. Our results provide a possible explanation of lower guarantee insurance fees observed in the market than those predicted from the insurer’s perspective. Numerical experiments are conducted to illustrate the results.

Study on Applicability of FEMA Formula in Prediction of Impact Load by Tsunami Drifting Vessels on Coastal Zone Structures

2020 ◽  
Author(s):  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Hiroaki Eto ◽  
Yasuhiro Aida ◽  
Kazuki Murata
Keyword(s):  
Numerical Experiments ◽  
Impact Load ◽  
Particle Method ◽  
Large Vessel ◽  
Action Point ◽  
Safe Side ◽  
Mass Coefficient ◽  
Applicable Range ◽  
Inundation Height ◽  
The Impact

Abstract In this study, we consider and evaluate the applicability of the FEMA’s formula which is one of the main simple formulas for calculating impact forces through the comparison with our proposed numerical simulation model. We investigated the situation of collision with a thin structure such as a pillar by numerical experiments based on the particle method, in particular, we focus on the case where the drifting speed is fast in targeting the quay of Shimizu Port, Shizuoka prefecture. We compared the results of numerical experiments obtained by detailed simulations with FEMA’s formula and evaluated the applicable range of FEMA s formula for huge vessels. As results, it was suggested that the overestimation was occurred with FEMA’s formula for large vessel using the inundation height and its velocity. FEMA’s formula calculates the impact force of large vessel on the safe side if the drifting vessel speed is used: the condition of added mass coefficient changes the results, but these indicate the safe side in this study. On the other hand, the results of safety sides are fluctuated depending on the height of the action point of force. Therefore, we confirmed that there is a need to examine the height of the impact point when using FEMA’s formula for large vessels.

Sign in / Sign up

Export Citation Format

Share Document