scholarly journals Inverse approach to estimating larval dispersal reveals limited population connectivity along 700 km of wave-swept open coast

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160370 ◽  
Author(s):  
Sarah O. Hameed ◽  
J. Wilson White ◽  
Seth H. Miller ◽  
Kerry J. Nickols ◽  
Steven G. Morgan
Keyword(s):  
Larval Dispersal ◽  
Demographic Data ◽  
Field Measurements ◽  
Population Connectivity ◽  
Inverse Approach ◽  
Open Coast ◽  
Novel Approach ◽  
Extensive Field ◽  
Larval Production ◽  
Petrolisthes Cinctipes

Demographic connectivity is fundamental to the persistence and resilience of metapopulations, but our understanding of the link between reproduction and recruitment is notoriously poor in open-coast marine populations. We provide the first evidence of high local retention and limited connectivity among populations spanning 700 km along an open coast in an upwelling system. Using extensive field measurements of fecundity, population size and settlement in concert with a Bayesian inverse modelling approach, we estimated that, on average, Petrolisthes cinctipes larvae disperse only 6.9 km (±25.0 km s.d.) from natal populations, despite spending approximately six weeks in an open-coast system that was once assumed to be broadly dispersive. This estimate differed substantially from our prior dispersal estimate (153.9 km) based on currents and larval duration and behaviour, revealing the importance of employing demographic data in larval dispersal estimates. Based on this estimate, we predict that demographic connectivity occurs predominantly among neighbouring populations less than 30 km apart. Comprehensive studies of larval production, settlement and connectivity are needed to advance an understanding of the ecology and evolution of life in the sea as well as to conserve ecosystems. Our novel approach provides a tractable framework for addressing these questions for species occurring in discrete coastal populations.

scholarly journals Considering multiple process observables to determine material model parameters for FE-cutting simulations

2021 ◽  
Author(s):  
Marvin Hardt ◽  
Thomas Bergs
Keyword(s):  
Chip Thickness ◽  
Material Model ◽  
Experimental Investigations ◽  
Model Parameters ◽  
Inverse Approach ◽  
Local Material ◽  
Novel Approach ◽  
Validation Parameters ◽  
Multiple Process ◽  
Cutting Simulations

AbstractAnalyzing the chip formation process by means of the finite element method (FEM) is an established procedure to understand the cutting process. For a realistic simulation, different input models are required, among which the material model is crucial. To determine the underlying material model parameters, inverse methods have found an increasing acceptance within the last decade. The calculated model parameters exhibit good validity within the domain of investigation, but suffer from their non-uniqueness. To overcome the drawback of the non-uniqueness, the literature suggests either to enlarge the domain of experimental investigations or to use more process observables as validation parameters. This paper presents a novel approach merging both suggestions: a fully automatized procedure in conjunction with the use of multiple process observables is utilized to investigate the non-uniqueness of material model parameters for the domain of cutting simulations. The underlying approach is two-fold: Firstly, the accuracy of the evaluated process observables from FE simulations is enhanced by establishing an automatized routine. Secondly, the number of process observables that are considered in the inverse approach is increased. For this purpose, the cutting force, cutting normal force, chip temperature, chip thickness, and chip radius are taken into account. It was shown that multiple parameter sets of the material model can result in almost identical simulation results in terms of the simulated process observables and the local material loads.

scholarly journals A COMPARISON BETWEEN MODEL AND PROTOTYPE WAVES IN HARBOURS

1978 ◽  
Vol 1 (16) ◽  
pp. 38
Author(s):  
Sverre Bjordal ◽  
Alf Torum
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Field Measurements ◽  
Full Scale ◽  
Common Method ◽  
Test Results ◽  
Open Coast ◽  
The World ◽  
Mooring Forces ◽  
Absolute Basis

A common method of estimating the sheltering effects of different breakwater locations and layouts is to carry out physical model wave disturbance tests. Such tests have been carried out in different laboratories throughout the world for many years. But to our knowledge no reports are available in the literature showing comparison between model measurements and field measurements. The trend is that we know more and more on the wave cl imate along our coasts. Hence we have a better basis to make our economical calculations on breakwaters. We therefore also want to operate our models on a more absolute basis rather than on a comparative basis. The trend in recent years has also been to study breakwater locations and layouts in order to minimize mooring forces and ship movements. On this background VHL found a comparison between model test results and field measurements necessary. Full scale measurements of waves were carried out in two harbours by VHL during the winter 1976/77. This paper will present the results of the comparison of the model and the full scale measurements in Berlevag and Vard0 fishing harbours on the open coast of Finnmark in the northern part of Norway (Fig. I) . The model tests, as well as the full scale measurements, have been sponsored by the Norwegian State Harbour Authorities.

scholarly journals Probability of successful larval dispersal declines fivefold over 1 km in a coral reef fish

2011 ◽  
Vol 279 (1735) ◽  
pp. 1883-1888 ◽  
Author(s):  
Peter M. Buston ◽  
Geoffrey P. Jones ◽  
Serge Planes ◽  
Simon R. Thorrold
Keyword(s):  
Larval Dispersal ◽  
Isolation By Distance ◽  
Dispersal Distance ◽  
Population Connectivity ◽  
Marine Ecology ◽  
Sea Anemones ◽  
Marine Population ◽  
Amphiprion Percula ◽  
Distance Distributions ◽  
Dispersal Distances

A central question of marine ecology is, how far do larvae disperse? Coupled biophysical models predict that the probability of successful dispersal declines as a function of distance between populations. Estimates of genetic isolation-by-distance and self-recruitment provide indirect support for this prediction. Here, we conduct the first direct test of this prediction, using data from the well-studied system of clown anemonefish ( Amphiprion percula ) at Kimbe Island, in Papua New Guinea. Amphiprion percula live in small breeding groups that inhabit sea anemones. These groups can be thought of as populations within a metapopulation. We use the x- and y -coordinates of each anemone to determine the expected distribution of dispersal distances (the distribution of distances between each and every population in the metapopulation). We use parentage analyses to trace recruits back to parents and determine the observed distribution of dispersal distances. Then, we employ a logistic model to (i) compare the observed and expected dispersal distance distributions and (ii) determine the relationship between the probability of successful dispersal and the distance between populations. The observed and expected dispersal distance distributions are significantly different ( p < 0.0001). Remarkably, the probability of successful dispersal between populations decreases fivefold over 1 km. This study provides a framework for quantitative investigations of larval dispersal that can be applied to other species. Further, the approach facilitates testing biological and physical hypotheses for the factors influencing larval dispersal in unison, which will advance our understanding of marine population connectivity.

Valuation of growing stock using multisource GIS data, a stem quality database, and bucking simulation

2018 ◽  
Vol 48 (8) ◽  
pp. 888-897 ◽  
Author(s):  
Blanca Sanz ◽  
Jukka Malinen ◽  
Vesa Leppänen ◽  
Rubén Valbuena ◽  
Tuomo Kauranne ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Field Measurements ◽  
Product Yield ◽  
Optimization Methods ◽  
Raw Material ◽  
Diameter Distribution ◽  
Target Area ◽  
Product Price ◽  
Extensive Field ◽  
Stem Quality

Customer-oriented production as a sawmill strategy requires up-to-date information on the available raw material resources. Bucking is a process in which the tree stem is divided into products based on the roundwood user’s needs regarding products and their quality and dimensions. Optimization methods are employed in bucking to recover the highest value of the stem for a given product price matrix and requested length–diameter distribution. A method is presented here for assessing the value of harvestable timber stands based on their product yield. Airborne laser scanning, multispectral imagery, and field plots were used to produce timber statistics for a grid covering the target area. The statistics for the plots were generated from this grid. The value of the estimated tree list was assessed using a bucking-to-value simulator together with a stem quality database. Different product yield simulations in terms of volumes, timber assortment recoveries, wood paying capabilities (WPC) and value estimations based on the presented method, and extensive field measurements were compared. As a conclusion, this method can estimate WPC for pulpwood and sawlogs with root mean squared errors of 32.7% and 38.5%, respectively, relative to extensive field measurements.

Experimental Study of Local Mass Transfer From a Flat Plate in Uniform Flow Using Electronic Speckle Pattern Interferometry

Volume 1 ◽  
2004 ◽  
Author(s):  
Tara M. Dalton ◽  
David McGuire ◽  
Mark R. Davies
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Flat Plate ◽  
Concentration Profile ◽  
Speckle Pattern ◽  
Mass Transfer Rate ◽  
Leading Edge ◽  
Field Measurements ◽  
Electronic Speckle Pattern Interferometry ◽  
Novel Approach

In this paper an investigative study of the relationship between mass and momentum transport, which have a mutual dependence, is presented. Mass transfer is an important design consideration in engineering processes such as evaporation, chemical reactions, corrosion and mixing. The effect that Reynolds number and distance from the leading edge has on mass transport from fluid to fluid interface on flat plate geometry is examined. A concentration profile is developed above a surface by passing airflow across the plate containing a well of ethanol. The rate of mass transfer is obtained from the concentration profile produced as the ethanol vapour diffuses in the airflow. Measurements are taken using the non-intrusive optical technique of Electronic Speckle Pattern Interferometry (ESPI), which has not been applied in this manner before. This novel approach offers the ability to measure in real time the mass transfer rate. A phase-shifting algorithm is also employed to give whole field measurements. The experimental results compare well to the theoretical prediction, showing that as expected the Sherwood number increases with increasing Reynolds number.

Sufficient versus optimal climatic stability during the Late Quaternary: using environmental quality to guide phylogeographic inferences in a Neotropical montane system

2019 ◽  
Vol 100 (6) ◽  
pp. 1783-1807 ◽  
Author(s):  
Mariano Soley-Guardia ◽  
Ana Carolina Carnaval ◽  
Robert P Anderson
Keyword(s):  
Late Quaternary ◽  
Species Distributions ◽  
Molecular Data ◽  
Population Connectivity ◽  
Ecological Niche Models ◽  
Tropical Ecosystems ◽  
Climatic Oscillations ◽  
Novel Approach ◽  
Ecological Principle ◽  
Niche Models

Abstract Quaternary climatic oscillations affected species distributions worldwide, creating cycles of connectivity and isolation that impacted population demography and promoted lineage divergence. These effects have been well studied in temperate regions. Taxa inhabiting mesic montane habitats in tropical ecosystems show high levels of endemism and diversification in the distinct mountain ranges they inhabit; such a pattern has commonly been ascribed to past climatic oscillations, but few phylogeographic studies have tested this hypothesis. Here, we combine ecological niche models of species distributions with molecular data to study phylogeographic patterns in two rodents endemic to the highlands of Costa Rica and western Panama (Reithrodontomys creper and Nephelomys devius). In so doing, we apply a novel approach that incorporates a basic ecological principle: the expected positive relationship between environmental suitability and population abundance. Specifically, we use niche models to predict potential patterns of population connectivity and stability of different suitability levels during climatic extremes of the last glacial–interglacial cycle; we then test these predictions with population genetic analyses of a mitochondrial and a nuclear marker. The detailed predictions arising from the different levels of suitability were moderately to highly congruent with the molecular data depending on the species. Overall, results suggest that in these tropical montane ecosystems, cycles of population connectivity and isolation followed a pattern opposite to that typically described for temperate or lowland tropical ecosystems: namely, higher connectivity during the colder glacials, with isolation in montane refugia during the interglacials, including today. Nevertheless, the individualistic patterns for each species indicate a potentially wide gamut of phylogeographic histories reflecting particularities of their niches. Taken together, this study illustrates how phylogeographic inferences may benefit from niche model outputs that provide more detailed predictions of connectivity and finer characterizations of potential refugia through time.

Application of Artificial Neural Network Based Gas Path Diagnostics on Gas Pipeline Compressors

2020 ◽  
Author(s):  
Suleiman M. Suleiman ◽  
Yi-Guang Li
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Field Measurements ◽  
Discharge Temperature ◽  
Novel Approach ◽  
Wide Range ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Compressor Map ◽  
Map Data

Abstract This paper presents the development of an artificial neural network (ANN) Gas Path Diagnostics (GPD) technique applied to pipeline compression system for fault detection and quantification. The work detailed the various degradation mechanisms and the effect of such degradations on the performance of natural gas compressors. The data used in demonstrating the ANN diagnostics is so derived using an advanced thermodynamic performance simulation model of integrated pipeline and compressor systems, which has embedded empirical compressor map data and pipeline resistance model. Implantation of faults within the model is in such a way to account for faults degradations caused by fouling, erosion and corrosion, of various degrees of severities, to obtain wide range of corresponding simulated “true” measurements. In order to account for uncertainties normally encountered in field measurements, Gaussian noise distribution was combined with simulated true measurements, which depends on the instrument’s tolerances. Furthermore, since judicious measurements selection are crucial in ensuring flawless GPD predictions, a sensitivity and correlation analysis of the available measurements revealed that discharge temperature, rotational speed and torque are the most effective measurements for the diagnostics with acceptable degrees of accuracies. The measurements observability technique is a novel approach in pipeline compressor diagnostics. Analytical case studies of the developed method show that, a selected ANN architecture can detect and quantify faults related to degradation in efficiency and flow capacities in the presence of instrument error, varied operational and environmental conditions.

scholarly journals Population Connectivity and Larval Dispersal Using Geochemical Signatures in Calcified Structures

Oceanography ◽  
2007 ◽  
Vol 20 (3) ◽  
pp. 80-89 ◽  
Author(s):  
Simon Thorrold ◽  
Danielle Zacherl ◽  
Lisa Levin
Keyword(s):  
Larval Dispersal ◽  
Population Connectivity

Self‐potentials associated with the Yanacocha high‐sulfidation gold deposit in Peru

Geophysics ◽  
2002 ◽  
Vol 67 (3) ◽  
pp. 684-689 ◽  
Author(s):  
Mark Goldie
Keyword(s):  
Apparent Resistivity ◽  
Direct Relationship ◽  
Field Measurements ◽  
Gold Deposits ◽  
Mineral Deposits ◽  
Silica Body ◽  
High Sulfidation ◽  
Extensive Field ◽  
Self Potential ◽  
Peak Value

Significant self‐potential (SP) anomalies characterize the large silica bodies associated with high‐sulfidation oxide gold deposits in the Yanacocha district, Peru. Large SP effects and high apparent resistivities have been observed that coincide with areas of intense silicification. Negative SP anomalies of several volts have been routinely recorded on numerous projects and deposits. The peak value measured was −10.2 V. A direct relationship is shown to exist between the magnitude of an SP response and the size and apparent resistivity of a silica body. Extensive field measurements over numerous high‐sulfidation deposits show that the negative SP effect increases with the size and/or resistivity contrast associated with these unique mineral deposits.

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