Browsing by Author "Nguyen-Quang, Tri"

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Detection of cyanotoxins in Lake Torment (Nova Scotia, Canada)
(Lviv Politechnic Publishing House, 2019-02-26) Hushchyna, Kateryna; McLellan, Kayla; Nguyen-Quang, Tri; Dalhousie University
This paper will update some information related to cyanotoxins detected in lake Torment, a recreational freshwater body in Nova Scotia, Canada. The goal of our paper is to present the detected toxins released by Toxic Algal Blooms and introducing the method of measurement by using the ELISA test. The results can show a very potential approach of toxin detection which could be applied in Ukraine or other countries where cyanotoxin detection in fresh and marine water ecosystems are still not well developed.
Linear stability analysis for the thermotactic microorganisms in porous media
(Publishing House of Lviv Polytechnic National University, 2017) Alloui, Zineddine; Nguyen-Quang, Tri; Département du Socle commun des Sciences et Technique, Faculté de Technologie Université El-Hadj-Lakhdar Batna, Algérie; Engineering Department, Faculty of Agriculture, Dalhousie University, Canada
Thermotaxis or motion in the field of temperature gradient is a very common phenomenon and can be found in many events in nature, from biological ones to the migration of colloidal particles. In this paper, we suggest a deterministic model to describe the collective behavior of a microorganism population with a general form of stimuli gradient-based taxis in porous media. This population has the mass density slightly heavier than the water density and forms a suspension. The suspended cells are actively in motion with a thermotaxis behavior (temperature gradient follower). Based on an Eulerian framework, the model comprises basically the Darcy equation for the fluid motion in porous media, equation of cell conservation for the microorganism population and equation of conservation for the considered stimuli. To take into account the density effects, the Boussinesq’s approximation will be used. Linear stability analysis shows that there are interesting effects of temperature on the bioconvection pattern of the thermotactic microorganisms.
Mathematical simulation for algal growth in the water reservoirs of Moncton city (New Brunswick, Canada) by the supervised learning classifier
(Lviv Politechnic Publishing House, 2018-02-01) Sabir, Qurat-Ul An; Nadeem, Muhammad; Nguyen-Quang, Tri; Dalhousie University
Mathematical model is a good approach to deal with the coupling effects of governing parameters in algal bloom growth. Among manymodels to deal with combining factors and data-based supervised learning classifiers, the Artificial Neural Network (ANN) has the most significant impact on the development of bloom pattern. The objective of this paper is to use the Artificial Neural Network (ANN) model to simulate the growth of harmful algae under environmental factors that can lead to bloom pattern in two reservoirs of Moncton city (Canada) with the collected data fromtwo years of observation 2016–2017.
The first step to sketch the spatio-temporal evolution of biochemical and physical parameters involving in the Harmful Algal Blooms (HAB) in Mattatall Lake (Nova Scotia, Canada)
(Publishing House of Lviv Polytechnic National University, 2016) Nguyen-Quang, Tri; Lieou, Kien-Chinh; Hushchyna, Kateryna; Nguyen, Tri-Dung; Sharifi Mood, Negar; Nadeem, Muhammad; McLellan, Kayla; Murdymootoo, Kalaivani; Merks, Emily; Hirtle, Rachel
Many watercourses in Nova Scotia (Canada) have recently had algal blooms in a surprisingly increasing way in frequency and diversity without any good understanding or explanation about causes and effects. The blooms triggered in Mattatall Lake (Wentworth, Nova Scotia) have many particular aspects: toxic species domination, nutrients increasing on a monthly basis, and blooms that co-exist with icy conditions. In this paper, we suggest an approach to create a map system with an appropriate interpolation and validation of necessary data in order to deal with this issue in Mattatall Lake and to contribute to the analysis framework and management plan on the entire area. Our long-term objective is aiming to suggest a modeling process for the entire watershed.
Using the Modified Redfield Ratio to estimate Harmful Algal Blooms
(Lviv Politechnic Publishing House, 2017-03-21) Hushchyna, Kateryna; Nguyen-Quang, Tri; Biofluids and Biosystems Modeling Lab (BBML)
Many waterbodies across Nova Scotia (Canada) have been experiencing algal blooms occurring in large numbers and diversity, without knowledge or understanding about their causes and effects. Algal blooms have appeared in Mattatall Lake (ML) and other lakes of the province in recent years. ML experienced severe algal blooms in 2013. During the fall of 2014, massive algal blooms appeared in ML, and persisted until late December 2014. The blooms have a pattern of being nontoxic in the summer and potentially toxic in the fall-winter season, with nutrients increasing on a monthly basis. This phenomenon is unusual as algal blooms have not been known to last until the winter season or coexist with icy conditions. The dominant species in this bloom was identified to be Anabaena planctonica (Dolicospermum planctonicum) with a cell count around 250 000 cells/mL, which may produce the neurotoxin Anatoxin-a. This cell count is approximately two and a half times higher than the alert level 2 guideline from World Health Organization’s drinking water standards (WHO, 2003). The goal of this paper is to use an index (Modified Redfield Ratio, hereafter called MRR) to estimate the HAB occurrence the Mattatall lake (Nova Scotia, Canada), served as a pilot site for our pioneering systematic study in order to evaluate the recent bloom phenomena in the entire province of Nova Scotia.