Evidence of economical territory selection in a cooperative carnivore

2021 ◽  
Vol 288 (1946) ◽  
pp. 20210108
Author(s):  
Sarah N. Sells ◽  
Michael S. Mitchell ◽  
Kevin M. Podruzny ◽  
Justin A. Gude ◽  
Allison C. Keever ◽  
...  
Keyword(s):  
Mechanistic Model ◽  
Territory Size ◽  
Causal Mechanism ◽  
Location Data ◽  
Mechanistic Approach ◽  
Wide Range ◽  
Conservation Actions ◽  
Ecological Patterns ◽  
Territory Selection ◽  
Access To Food

As an outcome of natural selection, animals are probably adapted to select territories economically by maximizing benefits and minimizing costs of territory ownership. Theory and empirical precedent indicate that a primary benefit of many territories is exclusive access to food resources, and primary costs of defending and using space are associated with competition, travel and mortality risk. A recently developed mechanistic model for economical territory selection provided numerous empirically testable predictions. We tested these predictions using location data from grey wolves ( Canis lupus ) in Montana, USA. As predicted, territories were smaller in areas with greater densities of prey, competitors and low-use roads, and for groups of greater size. Territory size increased before decreasing curvilinearly with greater terrain ruggedness and harvest mortalities. Our study provides evidence for the economical selection of territories as a causal mechanism underlying ecological patterns observed in a cooperative carnivore. Results demonstrate how a wide range of environmental and social conditions will influence economical behaviour and resulting space use. We expect similar responses would be observed in numerous territorial species. A mechanistic approach enables understanding how and why animals select particular territories. This knowledge can be used to enhance conservation efforts and more successfully predict effects of conservation actions.

A Mechanistic Approach to the Prediction of Material Removal Rates in Rotary Ultrasonic Machining

1995 ◽  
Vol 117 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Z. J. Pei ◽  
D. Prabhakar ◽  
P. M. Ferreira ◽  
M. Haselkorn
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Diamond Particle ◽  
Machining Parameters ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Stabilized Zirconia ◽  
Mechanistic Approach ◽  
Wide Range

An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators.

Prediction of High Viscosity Liquid/Gas Two-Phase Slug Length in Horizontal and Slightly Inclined Pipelines

2021 ◽  
Author(s):  
Omar Shaaban ◽  
Eissa Al-Safran
Keyword(s):  
Numerical Optimization ◽  
Flow Behavior ◽  
Mechanistic Model ◽  
High Viscosity ◽  
Oil Well ◽  
Liquid Slug ◽  
Two Phase ◽  
Proposed Model ◽  
Wide Range ◽  
Flow Closure

Abstract The production and transportation of high viscosity liquid/gas two-phase along petroleum production system is a challenging operation due to the lack of understanding the flow behavior and characteristics. In particular, accurate prediction of two-phase slug length in pipes is crucial to efficiently operate and safely design oil well and separation facilities. The objective of this study is to develop a mechanistic model to predict high viscosity liquid slug length in pipelines and to optimize the proper set of closure relationships required to ensure high accuracy prediction. A large high viscosity liquid slug length database is collected and presented in this study, against which the proposed model is validated and compared with other models. A mechanistic slug length model is derived based on the first principles of mass and momentum balances over a two-phase slug unit, which requires a set of closure relationships of other slug characteristics. To select the proper set of closure relationships, a numerical optimization is carried out using a large slug length dataset to minimize the prediction error. Thousands of combinations of various slug flow closure relationships were evaluated to identify the most appropriate relationships for the proposed slug length model under high viscosity slug length condition. Results show that the proposed slug length mechanistic model is applicable for a wide range of liquid viscosities and is sensitive to the selected closure relationships. Results revealed that the optimum closure relationships combination is Archibong-Eso et al. (2018) for slug frequency, Malnes (1983) for slug liquid holdup, Jeyachandra et al. (2012) for drift velocity, and Nicklin et al. (1962) for the distribution coefficient. Using the above set of closure relationships, model validation yields 37.8% absolute average percent error, outperforming all existing slug length models.

Application of neural networks in membrane separation

2020 ◽  
Vol 36 (2) ◽  
pp. 265-310 ◽  
Author(s):  
Morteza Asghari ◽  
Amir Dashti ◽  
Mashallah Rezakazemi ◽  
Ebrahim Jokar ◽  
Hadi Halakoei
Keyword(s):  
Neural Networks ◽  
Chemical Engineering ◽  
Membrane Separation ◽  
Mechanistic Model ◽  
Computing Time ◽  
Permeate Flux ◽  
Practical Applications ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Physical And Chemical

AbstractArtificial neural networks (ANNs) as a powerful technique for solving complicated problems in membrane separation processes have been employed in a wide range of chemical engineering applications. ANNs can be used in the modeling of different processes more easily than other modeling methods. Besides that, the computing time in the design of a membrane separation plant is shorter compared to many mass transfer models. The membrane separation field requires an alternative model that can work alone or in parallel with theoretical or numerical types, which can be quicker and, many a time, much more reliable. They are helpful in cases when scientists do not thoroughly know the physical and chemical rules that govern systems. In ANN modeling, there is no requirement for a deep knowledge of the processes and mathematical equations that govern them. Neural networks are commonly used for the estimation of membrane performance characteristics such as the permeate flux and rejection over the entire range of the process variables, such as pressure, solute concentration, temperature, superficial flow velocity, etc. This review investigates the important aspects of ANNs such as methods of development and training, and modeling strategies in correlation with different types of applications [microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), etc.]. It also deals with particular types of ANNs that have been confirmed to be effective in practical applications and points out the advantages and disadvantages of using them. The combination of ANN with accurate model predictions and a mechanistic model with less accurate predictions that render physical and chemical laws can provide a thorough understanding of a process.

scholarly journals Adenomatoid Hyperplasia of The Oral Cavity: A Diagnostic Dilemma

2021 ◽  
Author(s):  
Ali ALTINDAĞ ◽  
Poyzan Bozkurt ◽  
Burak Bilecenoğlu ◽  
Kaan Orhan
Keyword(s):  
Oral Cavity ◽  
Correct Diagnosis ◽  
Age Distribution ◽  
Salivary Gland Tumor ◽  
Histological Evaluation ◽  
Gland Tumor ◽  
Diagnostic Dilemma ◽  
Location Data ◽  
Wide Range ◽  
Review Study

This review study presents literature review and discusses the clinical significance of Adenomatoid Hyperplasia, a commonly misdiagnosed lesion. This rare entity has been seldom presented and is not well enough described in the literature. Only 15 reports with 95 cases could be attained during the online literature search using the keywords: Adenomatoid, Tumor, Hyperplasia, Minor salivary Glands. Data revealed a tendency towards the male gender. Age distribution of patients did not reveal a tendency towards a specific age group but presented a peak incidence in the 4th and 5th decades. Location data revealed a tendency towards the palate, especially the hard palate. Most of the presented cases were asymptomatic and the most common initial diagnosis made was salivary gland tumor. It was concluded that, adenomatoid hyperplasia of the oral cavity may resemble a wide range of pathologies and in order to differentiate and to achieve a correct diagnosis, histological evaluation is fundamental.

AYMA: Mechanistic Probabilistic System To Evaluate Flexible Pavement Performance

1998 ◽  
Vol 1629 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Manuel Ayres ◽  
Matthew W. Witczak
Keyword(s):  
Low Temperature ◽  
Mechanistic Model ◽  
Permanent Deformation ◽  
Probabilistic Approach ◽  
Fatigue Cracking ◽  
Flexible Pavement ◽  
Analysis And Design ◽  
Mechanistic Approach ◽  
Low Temperature Cracking ◽  
User Friendly

A new rational mechanistic model for analysis and design of flexible pavement systems has been developed. Furthermore, a fundamental probabilistic approach was incorporated into this system to account for the uncertainty of material and environmental conditions. The system was integrated in a user-friendly Windows program with a variety of user-selected options that include widely used models and those recently developed in the Strategic Highway Research Program project. Three basic types of distress can be investigated separately or all together, including fatigue cracking, permanent deformation, and low-temperature cracking. The mechanistic approach makes use of the JULEA layered elastic analysis program to obtain pavement response. The system provides optional deterministic and probabilistic solutions, accounts for aging and temperature effects over the asphalt materials, variable interface friction, multiple wheel loads, and user-selected locations for analysis. Tabular and graphical results provide expected distress values for each month as well as their variability, probability of failure, and assessment of the overall reliability of the pavement relative to each type of distress for a user-selected failure criterion. Only the load-associated module of AYMA is presented; a separate work describes the low-temperature cracking analysis.

Mechanistic Prediction of CHF in Fuel Assembly Using the Subchannel Code CAPE

2009 ◽  
Author(s):  
Ryo Yoshida ◽  
Kenji Yoshida ◽  
Isao Kataoka ◽  
Masanori Naito
Keyword(s):  
Fuel Assembly ◽  
Mechanistic Model ◽  
Safety Evaluation ◽  
Heat Fluxes ◽  
Deposition Rates ◽  
Benchmark Test ◽  
Transition Analysis ◽  
Fuel Bundle ◽  
Wide Range ◽  
The Impact

In order to predict the critical power or void fraction in BWR fuel bundles and the DNB heat flux of PWR fuel assemblies, the boiling transition analysis code called “CAPE” with mechanistic models has been developed in the IMPACT project by NUPEC. The objective of the CAPE code development is to perform with good accuracy the safety evaluation for a new type or improved fuel bundle design of BWR and PWR without full-scale experiments or any tuning parameters in the analysis code. In the present study dryout heat fluxes of BWR fuel assembly were analyzed by the CAPE code and compared with experimental data of BFBT benchmark test carried out by NUPEC. In the CAPE code, mechanistic model of liquid film dryout in annular flow is used considering entrainment and deposition of droplet. In such mechanistic prediction of dryout, the correlations of entrainment and deposition rates play quite important roles and many correlations have been developed. In addition to the original correlations in the CAPE code, several typical correlations, which are widely used in the analysis of annular dispersed flow, were tested for the prediction of dryout. The results indicated that the CAPE code satisfactorily predicted dryout heat fluxes of fuel assembly for wide range of pressure, mass flux, subcooling and bundle geometries obtained in BFBT benchmark test. The accuracy of prediction depends upon the combination of correlations of entrainment and deposition rates. The evaluation of correlations of entrainment and deposition rates was carried out.

Application of Siemens 840Di System in the Reconstruction of KISC Roll Collar Grinder

2013 ◽  
Vol 437 ◽  
pp. 740-743
Author(s):  
Hai Rui Wang ◽  
Ya Li ◽  
Jian Ying Wang ◽  
Yong Yi Liao
Keyword(s):  
High Speed ◽  
Mechanistic Model ◽  
Linear Interpolation ◽  
Sculptured Surfaces ◽  
Machining Center ◽  
Mechanistic Approach ◽  
High Feed ◽  
Path Lengths ◽  
Siemens 840D

This work studies the reconstruction of high-speed roll grinder for sculptured surfaces with high feed rates. Experiments and predictions were focused on representative surfaces of dies and molds, whose geometric complexity and complexity distribution were modified parametrically. CNC programs for machining these surfaces were executed in a HERKULES HSF2CNC machining center with a SIEMENS 840D controller, with different levels of programmed feed rate. Discrepancies between programmed and actual feed rates were evaluated. A mechanistic approach for roll grinder in high-speed milling of sculptured surfaces is proposed. The mechanistic model construction is based on: (a) the frequency distribution of linear interpolation path lengths in the CNC program and (b) a characterization of the machine tool for brisk and smooth movements. Two case studies were used to demonstrate the effectiveness of the proposed approach. The reconstruction model is capable of the manufacturing.

Investigation of the Influence of Elevated Pressure on Subcooled Boiling Flow—Model Evaluation Toward Generic Approach

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Sara Vahaji ◽  
Sherman Chi Pok Cheung ◽  
Guan Heng Yeoh ◽  
Jiyuan Tu
Keyword(s):  
Mechanistic Model ◽  
Elevated Pressure ◽  
Nucleation Site ◽  
Empirical Models ◽  
Mechanistic Modeling ◽  
Force Balance ◽  
Balance Model ◽  
Subcooled Boiling ◽  
Flow Conditions ◽  
Wide Range

Modeling subcooled boiling flows in vertical channels has relied heavily on the utilization of empirical correlations for the active nucleation site density, bubble departure diameter, and bubble departure frequency. Following the development and application of mechanistic modeling at low pressures, the capability of the model to resolve flow conditions at elevated pressure up to 10 bar is thoroughly assessed and compared with selected empirical models. Predictions of the mechanistic and selected empirical models are validated against two experimental data at low to elevated pressures. The results demonstrate that the mechanistic model is capable of predicting the heat and mass transfer processes. In spite of some drawbacks of the currently adopted force balance model, the results still point to the great potential of the mechanistic model to predict a wide range of flow conditions in subcooled boiling flows.

The significance of multiple causes and coincidence in the geological record: from clam clusters to Cretaceous catastrophe

2001 ◽  
Vol 38 (2) ◽  
pp. 271-292 ◽  
Author(s):  
Cameron J Tsujita
Keyword(s):  
Time Scales ◽  
Mass Extinction ◽  
Flood Basalt ◽  
Global Scale ◽  
Causal Mechanism ◽  
Great Expectations ◽  
Geological Record ◽  
Wide Range ◽  
Planktotrophic Larvae ◽  
Mass Extinction Event

Specific causes of unusual events recorded in the geological record are commonly difficult to distinguish and isolate; in some instances, event strata contain features that cannot be explained by a single causal mechanism. Unicausal hypotheses, when applied to complex problems, can lead to the misidentification, misinterpretation, and force-fitting of observations ("great expectations syndrome"). The close timing or temporal overlap of significant events, although statistically improbable on short time scales, becomes possible on long time scales. Event coincidence may occur on a wide range of scales, from local to global. On the local scale, a multiple-event interpretation is offered for both the concentration and clustering of bivalves at specific levels within the Upper Cretaceous Bearpaw Formation of southern Alberta. For this example, the relative timing of fluctuations in benthic substrate texture, oxygen concentration, abundance of planktotrophic larvae, and degree of sea-floor scouring was crucial to the formation and preservation of shell concentrations. On the sharply contrasted global scale, the implications of multiple events warrant much closer consideration than they have received hitherto in terms of major proposed causes for the Cretaceous–Tertiary (K–T) mass-extinction event: bolide impact, sea-level change, climatic change, and flood-basalt volcanism. By considering the predictable effects of these synchronous factors, both individually and in combination, a multiple-cause explanation of the K–T mass extinction emerges as entirely plausible. Certainly it needs to be considered in all future investigations of this important issue.

scholarly journals Linking an economic model for European agriculture with a mechanistic model to estimate nitrogen and carbon losses from arable soils in Europe

2008 ◽  
Vol 5 (1) ◽  
pp. 73-94 ◽  
Author(s):  
A. Leip ◽  
G. Marchi ◽  
R. Koeble ◽  
M. Kempen ◽  
W. Britz ◽  
...  
Keyword(s):  
Economic Model ◽  
Large Scale ◽  
Agricultural Soils ◽  
Mechanistic Model ◽  
Ghg Emissions ◽  
Nitrogen Budget ◽  
Environmental Response ◽  
The European Union ◽  
Arable Soils ◽  
Wide Range

Abstract. A comprehensive assessment of policy impact on greenhouse gas (GHG) emissions from agricultural soils requires careful consideration of both socio-economic aspects and the environmental heterogeneity of the landscape. We developed a modelling framework that links the large-scale economic model for agriculture CAPRI (Common Agricultural Policy Regional Impact assessment) with the biogeochemistry model DNDC (DeNitrification DeComposition) to simulate GHG fluxes, carbon stock changes and the nitrogen budget of agricultural soils in Europe. The framework allows the ex-ante simulation of agricultural or agri-environmental policy impacts on a wide range of environmental problems such as climate change (GHG emissions), air pollution and groundwater pollution. Those environmental impacts can be analyzed in the context of economic and social indicators as calculated by the economic model. The methodology consists of four steps: (i) definition of appropriate calculation units that can be considered as homogeneous in terms of economic behaviour and environmental response; (ii) downscaling of regional agricultural statistics and farm management information from a CAPRI simulation run into the spatial calculation units; (iii) designing environmental model scenarios and model runs; and finally (iv) aggregating results for interpretation. We show the first results of the nitrogen budget in croplands in fourteen countries of the European Union and discuss possibilities to improve the detailed assessment of nitrogen and carbon fluxes from European arable soils.

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