Daniel P Zielinski

Bubble Curtain Deflection Screen Diverts the Movement of both Asian and Common Carp

AbstractBubble curtains are a relatively simple type of behavioral deterrent that produces acoustic and hydrodynamic fields that could serve as a management tool to reduce movement of Asian carp species in many locations. In a proof-of-concept laboratory study, we tested whether two Asian carp species, the Silver Carp Hypopthalmichthys molitrix and the Bighead Carp H. nobilis, will avoid bubble curtains, and to the same extent as the Common Carp Cyprinus carpio, which has a similarly specialized hearing system. We explored the theory and application of a bubble curtain deflection screen using a split-passage experimental channel equipped with angled bubble curtains while mapping both pressure and particle motion (sound) fields. The bubble curtain reduced passage of all three species through the experimental channel by 73–80% while producing sound between 100 and 1000 Hz at 145 dB, well within the hearing range of all three carp. While Common Carp were diverted to an unblocked channel, the Asian carp speci...

The control-volume weighted flux scheme (CVWFS) for nonlocal diffusion and its relationship to fractional calculus

In diffusion transport, the flux at a point is typically modeled in terms of the local gradient of a potential. When heterogeneities are present, this local model can break down and it may be more appropriate to model the diffusion flux as a weighted sum of gradients present throughout the domain. Here a discrete nonlocal flux model—consistent with control-volume implementations—is developed. This scheme is referred to as the control-volume weighted flux scheme (CVWFS). The key component is the modeling of the diffusion flux at a given control-volume face in terms of a weighted sum of gradients at that face and at faces up- and downstream. Criteria for choosing the weights are proposed. This results in numerical solution schemes in which the coefficient matrix is diagonally dominant, has positive off-diagonal elements, and zero row sums. For a particular power-law weighting scheme it is shown how the CVWFS is related to the definition of the Caputo fractional derivative and the one-shift Grünwald approximation of the Riemann-Liouville fractional derivative. On developing transients and boundary condition treatments, the accuracy and suitability of the CVWFS scheme is demonstrated by solving a number of problems governed by Caputo fractional diffusion equations.

A random walk solution for fractional diffusion equations

Purpose – The purpose of this paper is to develop an alternative numerical approach for describing fractional diffusion in Cartesian and non‐Cartesian domains using a Monte Carlo random walk scheme. The resulting domain shifting scheme provides a numerical solution for multi‐dimensional steady state, source free diffusion problems with fluxes expressed in terms of Caputo fractional derivatives. This class of problems takes account of non‐locality in transport, expressed through parameters representing both the extent and direction of the non‐locality.Design/methodology/approach – The method described here follows a similar approach to random walk methods previously developed for normal (local) diffusion. The key differences from standard methods are: first, the random shifting of the domain about the point of interest with, second, shift steps selected from non‐symmetric, power‐law tailed, Levy probability distribution functions.Findings – The domain shifting scheme is verified by comparing predictive sol...

A control volume finite element method with spines for solutions of fractional heat conduction equations

ABSTRACT The focus of this paper is the numerical solution of space-fractional heat conduction equations. Typical numerical treatments for fractional diffusion equations (FDEs) are constructed to function on structured grids and cannot be readily applied to problems in arbitrarily shaped domains. Presented is an unstructured control volume finite element method for the solution of FDEs in non-Cartesian domains. This method approximates the fractional derivative flux at given integration points with a weighted sum of gradients along orthogonal spines. Accuracy and utility of the approach are demonstrated by solution of one- and two-sided FDEs in rectangular and cylindrical domains.

Aquatic Invasive Species in the Great Lakes Region: An Overview

ABSTRACT Aquatic invasive species (AIS) are of concern in North America due to their devastating impacts on ecosystems and economies. The Great Lakes region is particularly vulnerable to AIS introduction and establishment with at least 184 nonindigenous species reported in this region from a large number of taxa including viruses, bacteria, diatoms, protozoa, arthropods, mollusks, fish, and plants. Representative species from these groups were explored, describing the features of their natural history and current efforts in prevention and control. Specifically, five AIS that are expected to spread to novel areas in the region are discussed: viral hemorrhagic septicemia virus and heterosporis (pathogens affecting fish), starry stonewort (an alga), zebra mussels (a bivalve), and carps (fishes). Novel strategies for AIS control include next-generation sequencing technologies, gene editing, mathematical modeling, risk assessment, microbiome studies for biological control, and human-dimension studies to address tensions related to AIS management. Currently, AIS research is evolving to adapt to known technologies and develop novel technologies to understand and prevent AIS spread. It was found that AIS control in this region requires a multidisciplinary approach focusing on the life history of the species (e.g., pheromones), adaptive management of anthropogenic structures (e.g., bubble curtains), and the integration of human dimensions to develop efficient management plans that integrate local citizens and management agencies.

Silver, bighead, and common carp orient to acoustic particle motion when avoiding a complex sound

Behavioral responses of silver carp (Hypopthalmichthys molitrix), bighead carp (H. nobilis), and common carp (Cyprinus carpio) to a complex, broadband sound were tested in the absence of visual cues to determine whether these species are negatively phonotaxic and the roles that sound pressure and particle motion might play mediating this response. In a dark featureless square enclosure, groups of 3 fish were tracked and the distance of each fish from speakers and their swimming trajectories relative to sound pressure and particle acceleration were analyzed before, and then while an outboard motor sound was played. All three species exhibited negative phonotaxis during the first two exposures after which they ceased responding. The median percent time fish spent near the active speaker for the first two trials decreased from 7.0% to 1.3% for silver carp, 7.9% to 1.1% for bighead carp, and 9.5% to 3% for common carp. Notably, when close to the active speaker fish swam away from the source and maintained a nearly perfect 0° orientation to the axes of particle acceleration. Fish did not enter sound fields greater than 140 dB (ref. 1 μPa). These results demonstrate that carp avoid complex sounds in darkness and while initial responses may be informed by sound pressure, sustained oriented avoidance behavior is likely mediated by particle motion. This understanding of how invasive carp use particle motion to guide avoidance could be used to design new acoustic deterrents to divert them in dark, turbid river waters.