30921 research outputs found
Sort by
Effect of protein concentration and N2 gas injection on expansion dynamics and physical properties of extruded puffed snacks produced with corn starch and pea protein blends
No full textThe rising demand for nutritious, high-protein snacks has sparked interest in developing alternatives to traditional starch-based puffed snacks, which are often low in protein. However, incorporating high protein levels into puffed snacks poses challenges, as protein can negatively impact expansion and texture during extrusion. Traditional extrusion methods struggle to balance high protein content with acceptable snack quality. Nitrogen gas-assisted extrusion, a relatively new approach, introduces nitrogen gas as an additional blowing agent during extrusion. Despite its promise, a comprehensive understanding of how nitrogen gas affects expansion dynamics and the physical properties of high-protein extrudates is still limited.
This study comprehensively examined the effect of nitrogen gas injection pressure (0, 150, and 300 kPa) and feed protein content (0, 10, 20, 30, 40, and 50%) on extrudate expansion dynamics, expansion indices, density, microstructure, mechanical properties, and texture. In addition, the employment of high-speed thermal imaging and X-ray microtomography provided detailed and novel insights into nitrogen gas’s effects on expansion behavior and microstructural characteristics.
Results showed that the effects of nitrogen gas injection on extrudate properties are a function of feed protein content. Due to this significant interaction, it was challenging to isolate the impact of individual factors on specific extrudate properties. In general, high radial expansion, characterized by larger cell sizes, was desirable for enhancing extrudate crispness and crunchiness. However, this increase in radial expansion could possibly lead to greater extrudate hardness, which is typically considered unfavorable. Most prominently, nitrogen gas significantly improved longitudinal expansion, microstructure uniformity, and reduced cell wall thickness, particularly at the highest protein level (50%). At this protein level, nitrogen gas injection also led to lower extrudate density, reduced hardness, and improved crispness, mitigating the negative textural impacts typically associated with high protein levels.
This research filled a critical gap in literature by demonstrating the potential of nitrogen gas-assisted extrusion to enhance the quality of high-protein snacks, offering a viable solution for overcoming the challenges of protein incorporation in snack formulas. The findings provided a foundation for optimizing extrusion conditions in the production of healthier, protein-rich snacks that meet growing consumer demand for nutrition and sensory appeal.May 202
Direct numerical simulation of turbulent flow and heat transfer in a square duct roughened by longitudinal ribs
Get PDFThis thesis provides a detailed study of turbulent heat and fluid flow within a longitudinally-rib-roughened square duct using direct numerical simulations (DNS). To understand the rib effects on the velocity and temperature fields, DNS of turbulent convection in a smooth-wall duct is also performed which serves as a baseline case of comparison. The research consists of three major parts. In Part I, turbulent flow through a longitudinally-rib-roughened square duct is studied at a nominal bulk Reynolds number of . It is observed that the mean pattern of the secondary flows is sensitive to the presence of the ribs, and tertiary flows form at the roofs and roots of the ribs, leading to enhanced momentum transport throughout the cross-stream plane. The effects of ribs on the velocity field are further studied through analyses of the Reynolds stresses, budget balance of turbulence kinetic energy (TKE), and skewness and flatness factors of velocity fluctuations. In Part II, the influence of ribs on the statistical moments of the vorticity and velocity fields are demonstrated through analyses of the transport equation of the mean streamwise vorticity, enstrophy, as well as the joint probability density function (JPDF) of velocity fluctuations. Through a spectral analysis, it is found that the characteristic wavelength of the most energetic turbulent eddies is shortened in the ribbed duct. In Part III, turbulent heat transfer in three longitudinally-ribbed duct flows at nominal bulk Reynolds numbers of , 4410 and 9650 are studied. It is observed that the presence of longitudinal ribs strengthens the secondary flows, which become intensified as Reynolds number increases, leading to enhanced thermal energy transport. It is also observed that the presence of longitudinal ribs does not result in increased hydraulic losses. As the value of Reynolds number increases, the heat transfer coefficient increases monotonically. The effects of longitudinal ribs and Reynolds number on turbulent heat transfer in a square duct are further examined by analyzing the turbulent heat fluxes, budget balance of the temperature variance transport equation, and thermal structures in both the physical and spectral spaces.University of Manitoba Graduate FellowshipOctober 202
Comparing the boldness and exploration of co-occurring invasive marine crabs (Hemigrapsus sanguineus and Carcinus maenas)
Get PDFBoldness (i.e., the propensity to take risks) and exploratory behaviours can influence an animal’s ability to acquire resources, thus affecting competitive success. The Asian shore crab, Hemigrapsus sanguineus, and European green crab, Carcinus maenas, co-occur as highly invasive species in coastal areas of the United States, and more recently, in Atlantic Canada. Both crabs use structurally complex rocky intertidal habitat and consume similar macroalgal and invertebrate prey, such that they likely compete for resources. Competitive interactions between co-invaders could influence the success of either species, affecting their impacts on the ecosystem. Yet, there is a gap in research comparing behaviours, such as boldness or exploration, between co-invaders such as these crabs. Here, the boldness of H. sanguineus and C. maenas are compared by investigating their tendencies to exit preferred rocky habitat with shelter to explore an open and brightly lit area. The crabs’ exploratory tendencies are also compared, by evaluating if the species spontaneously alternate (i.e., preferentially explore regions that they have least recently explored), an indicator of efficient exploration. The two species had similar latencies when exiting the sheltered habitat, but C. maenas spent more time in the open area overall. Both crabs also tended to spontaneously alternate, but H. sanguineus had a greater tendency to do so than C. maenas, revealing for the first time the existence of significant differences in spontaneous alternation behaviour between invasive species. If the strong exploration ability of H. sanguineus can improve the species’ ability to find resources, it may have a competitive advantage over C. maenas in regions where the crabs co-occur
Identifying promising or priority effective adolescent, sexual and reproductive health interventions in Ghana: what frameworks should guide the selection of interventions?
Get PDFAbstract Background Adolescent sexual and reproductive health (ASRH) is an integral part of the global health agenda. It is strongly featured in the universal health coverage (UHC) agenda of the sustainable development goals (SDGs). The need to expand ASRH services to accelerate progress on UHC is urgent in Africa, compared to other regions, given its youthful population and unmet ASRH needs. Limited access to ASRH services increases the risk and vulnerability of adolescents to poor health outcomes such as unintended pregnancies, high adolescent birth rate, poor birth outcomes, high maternal and neonatal mortalities and high exposure to sexually transmitted infections. The unavailability and inaccessibility of ASRH interventions to adolescents and young adults in most African countries, including Ghana, arise from several limitations, including inadequate funding of interventions, cultural barriers and norms, lack of education, and inadequate supplies of ASRH services and commodities, among others. However, gains from investments in ASRH interventions, especially following the implementation of the Millennium Development Goals, highlight the importance of identifying and prioritising adequate funding for effective ASRH interventions. This paper identifies priority ASRH interventions that can potentially advance the sexual and reproductive health (SRH) needs of adolescents in Ghana to accelerate progress towards UHC. Methods Qualitative descriptive methods, combining literature review and stakeholder engagement, were used for this study. A literature review complemented by stakeholder engagement ensured the listing, ranking and validation of interventions. Results Adapting an established framework designed by the West African Health Organization (WAHO) through stakeholders’ engagement process, the paper identifies four of seven priority interventions ranked and validated by stakeholders for addressing the SRH needs of adolescents in Ghana. Consistent with the literature, several interventions exist to address ASRH needs. The most effective priority or promising four interventions in Ghana, according to stakeholders, include adolescent health clubs programmes, girls’ empowerment programmes through comprehensive sexuality education, national capacity-building programmes to deliver high-quality integrated family planning and comprehensive maternal health services, and electronic health (eHealth)/digital health programmes. Conclusion Identifying effective priority interventions for addressing the SRH needs of adolescents is a consultative process facilitated by proven and valid frameworks adapted to align with specific country contexts
Numerical investigation of pore distribution patterns on the linear and nonlinear mechanical behavior of porous materials
Get PDFPorous materials represent a class of materials widely used in various engineering and industrial applications due to their unique properties, such as lightweight and enhanced fluid permeability, which have drawn significant attention in recent years. The effective properties of porous materials are largely influenced by porosity, the spatial distribution of pores, and the interaction between the pores and the surrounding solid matrix. Existing methods, particularly micromechanics-based analytical formulas, exhibit fundamental limitations in handling high-porosity materials and extending the analysis beyond elastic region. In this thesis, the Microstructure-Free Finite Element Method (MF-FEM) is extended to characterize porous materials by modeling two different microstructures: regular and irregular, and analyzing their properties in both elastic and inelastic regimes. The MF-FEM results are compared with analytical approaches, using available experimental results as a baseline. The comparison demonstrates that MF-FEM predictions consistently exhibit strong agreement with experimental results, whereas the accuracy of micromechanics-based formulas remains conditional and highly dependent on their underlying assumptions. Beyond its reliability, MF-FEM also provides a cost-effective numerical approach for predicting and characterizing the mechanical properties of porous materials. Moreover, this study provides a comprehensive understanding of how different pore distributions, such as regular and irregular patterns, affect the overall mechanical properties in both linear and nonlinear regimes. These insights contribute to the efficient design of porous materials for various industrial applications, including automotive, aerospace, and biomedical engineering.October 202
Employing Optical Brain Imaging for Real-Time Assessment of Brain Functions During Immersive Virtual Reality: Harnessing Potential for Neurorehabilitation
Get PDFThis ongoing study introduces a cutting-edge integration of immersive Virtual Reality (iVR) and functional Near-Infrared Spectroscopy (fNIRS) to facilitate real-time monitoring of brain activity during iVR-based tasks. By combining a High Tech Computer Corporation (HTC) Vive Pro VR headset with a multichannel fNIRS system, the platform provides a portable, non-invasive solution for investigating motor and cognitive control functions under immersive conditions. The study focuses
on tasks that mimic real-world rehabilitation exercises, such as hand-grasping movements, designed to engage both motor and executive brain regions. Preliminary results from two healthy participants demonstrate robust hemodynamic responses in the Bilateral Motor Cortices (M1) and Dorso-Lateral Pre-Frontal Cortices (DLPFC) during iVR tasks, revealing increased neural activation compared to similar tasks performed in real-world and screen-based environments. Enhanced functional connectivity between the M1 and DLPFC was also observed, suggesting improved coordination of motor and cognitive processes. These findings highlight the potential of the iVR-fNIRS platform to capture unique patterns of brain engagement and functional activation during immersive virtual tasks. This novel approach addresses a critical gap in neurorehabilitation research by enabling continuous, real-time assessment of brain activity during therapy. The platform’s portability and resilience to motion make it well-suited for clinical applications, including personalized rehabilitation programs for patients with neurological conditions. Future work will extend the study to larger populations and
incorporate additional cognitive tasks to validate the platform’s versatility and reliability. This research paves the way for innovative neuroscience tools and therapeutic interventions driven by Artificial Intelligence (AI), enhancing our ability to monitor and optimize brain function in immersive virtual environments
Manipulation and utilization of electron-accepting character in π-extended compounds
No full textAs the zeitgeist that inhabits a society evolves, the role of the scientist follows close behind. In the current era the modern chemist is charged with many responsibilities, almost all of which require an interdisciplinary approach; from teaming up with biologists to undertake the development of new therapeutic drugs to collaborating with physicists and engineers for the design of functional materials. One responsibility entrusted to the modern chemist is the development of methods and materials that adhere to the principles of sustainability, energy efficiency, and minimized environmental or ecological harm, while maintaining industrial viability.
This thesis explores the concepts of environmental consideration and energetic efficiency within the field of chemistry with a focus on the role of unsaturated organic (hetero)cyclic materials, and their ability to accept electrons or electron density. Chapter 2 will outline the development of a sustainable electrochemical method capable of hydrogenating unsaturated organic materials using a glassy carbon electrode, graphite counter electrode, and a mild concentration of acetic acid under an applied mild reductive potential. Highlighting the potential underutilization of electrosynthetic chemistry, an analogue of the industrially relevant molecule cyclandelate is able to be formed using these mild electrochemical conditions with a yield and mass recovery of >99 %.
Chapters 3 and 4 will detail the preparation of two highly benzannulated analogues of 2,2'-bipyridine called biphe (Chapter 3) and p-biphe (Chapter 4) and the subsequent investigation into their charge accepting ability for potential use in the development of energy efficient solar harvesting and deep-red emitting devices. For example, the prepared novel heteroleptic complexes Ru(bpy)2(biphe)2+ and Ir(ppy)2(p-biphe)+ showcase deep-red, room temperature phosphorescence, measured at 752 nm and 813 nm respectively. The 3d metal containing complex Cu(xantphos)(p-biphe)+ showcases very deep-red phosphorescence at 77 K containing a long charge transfer lifetime (40 µs), with an emission maximum measured at 811 nm.
Chapter 5 continues the study of materials capable of efficient solar harvest but approaches the problem from another angle - utilizing a different organic chromophore framework colloquially referred to as BODIPY, which exhibits highly tunable optoelectronic properties and a very strong molar absorptivity.May 202
Performance evaluation of hollow-core slab reinforcement bar connections to masonry walls: Western Canada practice
No full textReinforcing steel bars are essential for connecting hollow-core slabs (HCS) to supporting structures, ensuring structural integrity and resistance to lateral in-plane loads. In Canada, 10M reinforcing bars are widely used to anchor HCS to supports. However, North American design provisions lack detailed guidelines for predicting the capacity and modes of failure of these connections, prompting further study to improve their reliability.
This research evaluates the performance of reinforcing bar connections between HCS and masonry walls, focusing on common detailing practices in Western Canada. Twelve full-scale specimens were tested under in-plane tensile and shear forces, assessing variables including connection type (end-bearing or side-connection), load direction relative to the masonry wall, bar shape (L-shaped or U-shaped), and slab location in a ten-story building.
Experimental results confirmed that all connections exceeded the code-prescribed tensile resistance for multi-storey buildings. Peak tensile resistance was primarily governed by friction and bond at the grout–HCS/masonry interface, with a notable contribution from the vertical wall reinforcement. Strain measurements and crack patterns demonstrated that the integrity ties remained inactive until cracking at the interface occurred. Once cracking initiated, the ties contributed to post-peak strength of the connection by restricting the HCS from sudden large displacements and loss of support, thereby enhancing structural integrity.
The results further showed that L-shaped bars in end-bearing connections exhibited greater strain after peak load, while U-shaped bars facilitated more uniform load distribution, reducing strain localization. Additionally, specimens located at intermediate floors exhibited enhanced load-carrying capacity, with the fifth-floor specimens demonstrating a 248% increase in capacity compared to roof-level specimens without parapets.
Shear tests of side-connections with hooked embedment length performed better than those anchored with adhesive, highlighting the significance of reinforcement continuity. End-bearing connections also demonstrated that bond and friction at grout-masonry interface along with vertical wall reinforcement were vital for resisting shear and maintaining connection ductility. The shear test results were consistent with the shear-friction model in Canadian standards, confirming its applicability for predicting HCS-to-masonry wall shear capacity. These findings enhance the understanding of connection behaviour and inform design practices for improved structural resilienceCanadian Standards Association
Multicrete Systems
Manitoba Masonry InstituteOctober 202
Estimation and evaluation of protein metabolism in a freshwater snail Planorbella duryi
Get PDFAnimal bioenergetics can be defined as the conversion chemical energy from food into forms that can be used in vivo for maintenance, development and growth as well as reproduction. Thus, metabolic strategies that maximize the efficiency of energy assimilation may be beneficial to animals, especially under changing environmental conditions like elevated temperatures. Protein metabolism is a major contributor to resting energetic costs in ectotherms and protein accretion is a central component of growth. Proteins are responsible as cellular catalysts, essential structural elements and are core to defense against heat damages. Hence, a thorough understanding of protein turnover can provide insights to how energy metabolism interacts with growth dynamics under temperature change. In this thesis, two developed methods are used to assess protein metabolism in adult as well as embryonic stages of the freshwater snail Planorbella duryi. Using a novel D5-phenylalanine tracer approach to protein metabolism to flood endogenous phenylalanine pools we measure protein metabolism in the adult snails and test the effect of temperature acclimation on both the kinetics of protein synthesis and degradation. A novel open-chambered respirometer was utilized for the estimation of protein metabolism cost during embryonic development. While biochemical processes are often associated with a 2-fold to 3-fold change per 10°C change in temperature, protein metabolism following acclimation suggests marked compensation for temperature effects in the adults. Embryonic snails showed a higher commitment of energy metabolism to protein synthesis, as may be expected given the rapid cellular turnover and growth during this life-stage.University of Manitoba, Faculty of ScienceOctober 202
Conservation of genetic diversity using life history predictors of adaptive potential
Get PDFBiodiversity loss is reducing population sizes globally, leading to a decline in genetic diversity. This is concerning, as genetic diversity is vital for species' survival and adaptation to future environmental change. Conservation frameworks, such as the International Union for Conservation of Nature (IUCN) Red List, assess extinction risk but overlook genetic diversity and adaptive potential. This is primarily because genetic data is not available for most species. My project directly addresses the lack of consideration of genetic diversity conservation framework by examining the relationship between adaptive potential and easy-to-measure life history traits. If easy-to-measure traits reflect adaptive potential, they can be used to guide conservation where direct estimates of adaptive potential are lacking. Adaptive potential reflects the additive genetic variance (VA) underlying fitness. VA reflects genetic diversity and capacity for adaptation and is used in calculating heritability. I hypothesized that life history traits (e.g., body mass, longevity, fecundity, and age of maturity) predict adaptive potential, measured by heritability. The data for heritability were derived from studies by Mittel et al. (2015), Holstad et
al. (2024), and life history trait data from Myhrvold et al. (2016). Data inclusion consisted of heritability measured for morphological, life history, behavioural, and physiological traits, for terrestrial vertebrate species and from wild populations. The relationship between heritability and life history traits was measured using generalized linear mixed models. My results revealed significant relationships between heritability and life history traits. Larger body mass and longer lifespan were associated with low heritability, while larger litter/clutch sizes and earlier ages of maturity were associated with high adaptive potential. Morphological heritability estimates exhibited stronger correlations with life history traits compared to other heritability estimates, suggesting they may be a more reliable proxy for predicting adaptive potential. These findings highlight the potential of using life history traits to infer species’ genetic diversity and adaptive potential, offering a valuable tool to improve conservation prioritization