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"Fleck, Brian"
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A Novel Approach Toward Fabrication of High Performance Thin Film Composite Polyamide Membranes
2016
A practical method is reported to enhance water permeability of thin film composite (TFC) polyamide (PA) membranes by decreasing the thickness of the selective PA layer. The composite membranes were prepared by interfacial polymerization (IP) reaction between meta-phenylene diamine (MPD)-aqueous and trimesoyl chloride (TMC)-organic solvents at the surface of polyethersulfone (PES) microporous support. Several PA TFC membranes were prepared at different temperatures of the organic solution ranging from −20 °C to 50 °C. The physico-chemical and morphological properties of the synthesized membranes were carefully characterized using serval analytical techniques. The results confirmed that the TFC membranes, synthesized at sub-zero temperatures of organic solution, had thinner and smoother PA layer with a greater degree of cross-linking and wettability compared to the PA films prepared at 50 °C. We demonstrated that reducing the temperature of organic solution effectively decreased the thickness of the PA active layer and thus enhanced water permeation through the membranes. The most water permeable membrane was prepared at −20 °C and exhibited nine times higher water flux compared to the membrane synthesized at room temperature. The method proposed in this report can be effectively applied for energy- and cost-efficient development of high performance nanofiltration and reverse osmosis membranes.
Journal Article
The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: A systematic review of ultraviolet radiation
by
Fleck, Brian A.
,
Dandnayak, Dhyey
,
Fleck, Natalie
in
Air Conditioning
,
Air flow
,
Air Pollution, Indoor
2022
Respiratory viruses are capable of transmitting via an aerosol route. Emerging evidence suggests that SARS-CoV-2 which causes COVID-19 can be spread through airborne transmission, particularly in indoor environments with poor ventilation. Heating, ventilation, and air conditioning (HVAC) systems can play a role in mitigating airborne virus transmission. Ultraviolet germicidal irradiation (UVGI), a feature that can be incorporated into HVAC systems, can be used to impede the ability of viruses to replicate and infect a host. We conducted a systematic review of the scientific literature examining the effectiveness of HVAC design features in reducing virus transmission—here we report results for ultraviolet (UV) radiation. We followed international standards for conducting systematic reviews and developed an a priori protocol. We conducted a comprehensive search to January 2021 of published and grey literature using Ovid MEDLINE, Compendex, and Web of Science Core. Two reviewers were involved in study selection, data extraction, and risk of bias assessments. We presented study characteristics and results in evidence tables, and synthesized results across studies narratively. We identified 32 relevant studies published between 1936 and 2020. Research demonstrates that: viruses and bacteriophages are inactivated by UV radiation; increasing UV dose is associated with decreasing survival fraction of viruses and bacteriophages; increasing relative humidity is associated with decreasing susceptibility to UV radiation; UV dose and corresponding survival fraction are affected by airflow pattern, air changes per hour, and UV device location; and UV radiation is associated with decreased transmission in both animal and human studies. While UV radiation has been shown to be effective in inactivating viruses and reducing disease transmission, practical implementation of UVGI in HVAC systems needs to consider airflow patterns, air changes per hour, and UV device location. The majority of the scientific literature is comprised of experimental, laboratory-based studies. Further, a variety of viruses have been examined; however, there are few studies of coronaviruses and none to date of SARS-CoV-2. Future field studies of UVGI systems could address an existing research gap and provide important information on system performance in real-world situations, particularly in the context of the current COVID-19 pandemic. This comprehensive synthesis of the scientific evidence examining the impact of UV radiation on virus transmission can be used to guide implementation of systems to mitigate airborne spread and identify priorities for future research. Trial registration PROSPERO 2020 CRD42020193968 .
Journal Article
The impact of heating, ventilation and air conditioning (HVAC) design features on the transmission of viruses, including the 2019 novel coronavirus (COVID-19): A systematic review of humidity
by
Fleck, Brian A.
,
Thornton, Gail M.
,
Dandnayak, Dhyey
in
Aerosols
,
Air Conditioning
,
Biology and Life Sciences
2022
The aerosol route has been a pathway for transmission of many viruses. Similarly, recent evidence has determined aerosol transmission for SARS-CoV-2 to be significant. Consequently, public health officials and professionals have sought data regarding the role of Heating, Ventilation, and Air Conditioning (HVAC) features as a means to mitigate transmission of viruses, particularly coronaviruses. Using international standards, a systematic review was conducted to comprehensively identify and synthesize research examining the effect of humidity on transmission of coronaviruses and influenza. The results from 24 relevant studies showed that: increasing from mid (40–60%) to high (>60%) relative humidity (RH) for SARS-CoV-2 was associated with decreased virus survival; although SARS-CoV-2 results appear consistent, coronaviruses do not all behave the same; increasing from low (<40%) to mid RH for influenza was associated with decreased persistence, infectivity, viability, and survival, however effects of increased humidity from mid to high for influenza were not consistent; and medium, temperature, and exposure time were associated with inconsistency in results for both coronaviruses and influenza. Adapting humidity to mitigate virus transmission is complex. When controlling humidity as an HVAC feature, practitioners should take into account virus type and temperature. Future research should also consider the impact of exposure time, temperature, and medium when designing experiments, while also working towards more standardized testing procedures. Clinical trial registration: PROSPERO 2020 CRD42020193968 .
Journal Article
Oxygen Saturation and Outcomes in Preterm Infants
by
Davis, Peter Graham
,
Askie, Lisa
,
Donoghoe, Mark
in
Algorithms
,
Biological and medical sciences
,
Calibration
2013
This report of the three BOOST II trials, undertaken to examine optimum oxygen saturation in extremely preterm infants, showed that targeting levels below 90% with the use of current oximeter calibrations was associated with increased mortality.
The clinically appropriate range for oxygen saturation in preterm infants is unknown. Trials in the 1950s showed that unrestricted oxygen increased the rate of severe retinopathy of prematurity. However, when oxygen was subsequently restricted, increased mortality was observed.
1
The first Benefits of Oxygen Saturation Targeting (BOOST) trial showed that in preterm infants who were still receiving oxygen at 32 weeks' gestation, targeting a higher oxygen-saturation range prolonged oxygen dependence.
2
Observational studies suggested that higher oxygen-saturation levels may increase rates of retinopathy of prematurity.
3
–
5
In five randomized, masked trials with similar protocols conducted in the United States,
6
Australia, New Zealand, . . .
Journal Article
Toward Sustainable Electricity Markets: Merit-Order Dynamics on Photovoltaic Energy Price Duck Curve and Emissions Displacement
by
Fleck, Brian A.
,
Weis, Tim
,
Durán-Castillo, Gloria
in
Air quality management
,
Alternative energy sources
,
Costs
2025
This paper examines how the slope of the merit-order curve and the share of non-zero-dollar dispatched energy affect photovoltaic (PV) price cannibalization and the declining market value of all generation types. Using historical merit-order data from Alberta, Canada—during its coal-to-gas transition—we simulated the introduction of zero-marginal-cost PV offers. The increased PV penetration rapidly suppresses midday electricity prices, forming a “duck curve” that challenges solar project economics. Emission reductions improve with rising carbon prices, indicating environmental benefits despite declining market revenues. Years with steeper merit-order slopes and lower non-zero-dollar dispatch shares show intensified price cannibalization and a reduced PV market value. The integration of battery storage alongside PV significantly flattened daily price profiles—raising the trough prices during charging and lowering the highest prices during discharging. While this reduces price volatility, it also diminishes the market value of all generation types, as batteries discharge at zero marginal cost during high-price hours. Battery arbitrage remains limited in low- and moderate-price regimes but becomes more profitable under high-price regimes. Overall, these dynamics underscore the challenges of integrating large-scale PV in energy-only markets, where price cannibalization erodes long-term investment signals for clean energy technologies. These insights inform sustainable energy policy design aimed at supporting decarbonization, and investment viability in liberalized electricity markets.
Journal Article
The impact of heating, ventilation and air conditioning
by
Dandnayak, Dhyey
,
Fleck, Brian A
,
Thornton, Gail M
in
Analysis
,
Disease transmission
,
HVAC equipment
2022
The aerosol route has been a pathway for transmission of many viruses. Similarly, recent evidence has determined aerosol transmission for SARS-CoV-2 to be significant. Consequently, public health officials and professionals have sought data regarding the role of Heating, Ventilation, and Air Conditioning (HVAC) features as a means to mitigate transmission of viruses, particularly coronaviruses. Using international standards, a systematic review was conducted to comprehensively identify and synthesize research examining the effect of humidity on transmission of coronaviruses and influenza. The results from 24 relevant studies showed that: increasing from mid (40-60%) to high (>60%) relative humidity (RH) for SARS-CoV-2 was associated with decreased virus survival; although SARS-CoV-2 results appear consistent, coronaviruses do not all behave the same; increasing from low (<40%) to mid RH for influenza was associated with decreased persistence, infectivity, viability, and survival, however effects of increased humidity from mid to high for influenza were not consistent; and medium, temperature, and exposure time were associated with inconsistency in results for both coronaviruses and influenza. Adapting humidity to mitigate virus transmission is complex. When controlling humidity as an HVAC feature, practitioners should take into account virus type and temperature. Future research should also consider the impact of exposure time, temperature, and medium when designing experiments, while also working towards more standardized testing procedures.
Journal Article
Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants
by
Donoghoe, Mark
,
Deshpande, Sanjeev
,
Cairns, Pamela
in
Australia
,
Child, Preschool
,
Clinical trials
2016
In two trials involving preterm infants, an oxygen-saturation target of 85 to 89% versus 91 to 95% resulted in nonsignificantly higher rates of death or disability at 2 years but in significantly increased risks of the combined outcome and of death alone in post hoc combined analyses.
The determination of the range of oxygen saturation that minimizes the competing risks of death, retinopathy of prematurity, and later disability in preterm infants is important.
1
,
2
The U.K. and Australian Benefits of Oxygen Saturation Targeting (BOOST)–II trials are two of five comparative effectiveness trials of the targeting of oxygen saturation in infants born before 28 weeks’ gestation.
3
–
8
These trials, known collectively as the Neonatal Oxygen Prospective Meta-analysis (NeOProM) Collaboration, were designed to compare the effects of a lower oxygen-saturation target range (85 to 89%) versus a higher target range (91 to 95%) on a primary outcome of death . . .
Journal Article
Poly (methyl methacrylate) grafted wheat straw for economical and eco-friendly treatment of oily wastewater
2022
The sustainable development of oil–gas and petrochemical industries necessitates the development of cost-effective and eco-friendly technologies to treat mass-produced oily wastewater discharge from these industries. This study applied a simple radical polymerization to enhance the oil adsorption efficiency of agricultural waste biomass wheat straw (WS) by grafting biocompatible poly(methyl methacrylate) (PMMA). Diesel oil adsorption from oil-in-water emulsion using the PMMA grafted WS was thoroughly studied for the first time in the quest of developing an economical and eco-friendly adsorbent for the adsorptive treatment of oily wastewater. The success of pre-treatment of pristine WS and the subsequent PMMA grafting were evaluated by SEM morphology, BET analysis, EDX and XPS elemental analysis, FTIR, and contact angle measurements. SEM images indicated that the inner interconnected tubular pore channels of WS are exposed significantly upon alkaline hydrogen peroxide pre-treatment. PMMA grafting substantially improved oil adhesivity, as evident from the 0° oil contact angle for WS-g-PMMA film. Oil absorptivity was thoroughly evaluated by batch oil adsorption study using variable adsorbent dosages and oil emulsion concentrations. The WS-g-PMMA exhibited explicitly higher adsorption capacity (
ca.
1129 mg/g) compared to that of the pristine (
ca.
346 mg/g) and pretreated (
ca.
741 mg/g) due to high accessibility to exposed inner interconnected tubular pore channels and strong hydrophobic interactions between the WS-g-PMMA surface and oil droplets. Langmuir and Freundlich adsorption isotherms were applied to evaluate the adsorption mechanism. The experimental data fit well with the Freundlich isotherm, clearly indicating the heterogeneity of adsorption sites, as well as multilayer adsorption of oil. The experimental adsorption data fit well with the pseudo-second-order rate equation with R
2
as high as 0.999, which confirmed the multilayer adsorption of oil. The high oil adsorption capacity of the WS-g-PMMA makes it a very promising material for oily wastewater treatment. The oil removal efficiency declined by < 4% at the end of 3 adsorption-regeneration cycles, indicating the possibility for long-term usage, which is beneficial for cost-effectiveness and lower frequency for end-use waste management. This will simultaneously resolve issues with the treatment of oily wastewater and facilitate the recycling of abundant quantities of waste WS. This study serves as a reference for analyzing the suitability of wheat straw for treating extremely challenging waste streams, such as steam assisted gravity drainage (SAGD) produced water containing BTEX and PAHs that are also hydrophobic like diesel oil.
Journal Article
Validation Process for Rooftop Wind Regime CFD Model in Complex Urban Environment Using an Experimental Measurement Campaign
by
Fleck, Brian A.
,
Versteege, Michael
,
Mattar, Sarah Jamal
in
Alternative energy
,
Approximation
,
complex urban geometry
2021
This research presents a validation methodology for computational fluid dynamics (CFD) assessments of rooftop wind regime in urban environments. A case study is carried out at the Donadeo Innovation Centre for Engineering building at the University of Alberta campus. A numerical assessment of rooftop wind regime around buildings of the University of Alberta North campus has been performed by using 3D steady Reynolds-averaged Navier–Stokes equations, on a large-scale high-resolution grid using the ANSYS CFX code. Two methods of standard deviation (SDM) and average (AM) were introduced to compare the numerical results with the corresponding measurements. The standard deviation method showed slightly better agreements between the numerical results and measurements compared to the average method, by showing the average wind speed errors of 10.8% and 17.7%, and wind direction deviation of 8.4° and 12.3°, for incident winds from East and South, respectively. However, the average error between simulated and measured wind speeds of the North and West incidents were 51.2% and 24.6%, respectively. Considering the fact that the upstream geometry was not modeled in detail for the North and West directions, the validation methodology presented in this paper is deemed as acceptable, as good agreement between the numerical and experimental results of East and South incidents were achieved.
Journal Article
A case control study examining the feasibility of using eye tracking perimetry to differentiate patients with glaucoma from healthy controls
by
Cameron, Lorraine A.
,
Murray, Ian C.
,
Minns, Robert A.
in
692/699/3161/3172
,
692/700/139
,
Aged
2021
To explore the feasibility of using Saccadic Vector Optokinetic Perimetry (SVOP) to differentiate glaucomatous and healthy eyes. A prospective case–control study was performed using a convenience sample recruited from a single university glaucoma clinic and a group of healthy controls. SVOP and standard automated perimetry (SAP) was performed with testing order randomised. The reference standard was a diagnosis of glaucoma based a comprehensive ophthalmic examination and abnormality on standard automated perimetry (SAP). The index test was SVOP. 31 patients with glaucoma and 24 healthy subjects were included. Mean SAP mean deviation (MD) in those with glaucoma was − 8.7 ± 7.4 dB, with mean SAP and SVOP sensitivities of 23.3 ± 0.9 dB and 22.1 ± 4.3 dB respectively. Participants with glaucoma were significantly older. On average, SAP sensitivity was 1.2 ± 1.4 dB higher than SVOP (95% limits of agreement = − 1.6 to 4.0 dB). SVOP sensitivity had good ability to differentiate healthy and glaucomatous eyes with a 95% CI for area under the curve (AUC) of 0.84 to 0.96, similar to the performance of SAP sensitivity (95% CI 0.86 to 0.97, P = 0.60). For 80% specificity, SVOP had a 95% CI sensitivity of 75.7% to 94.8% compared to 77.8% to 96.0% for SAP. SVOP took considerably longer to perform (514 ± 54 s compared to 267 ± 76 s for SAP). Eye tracking perimetry may be useful for detection of glaucoma but further studies are needed to evaluate SVOP within its intended sphere of use, using an appropriate design and independent reference standard.
Journal Article