Toronto Metropolitan University Open Journals
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Experimental Investigation of the Usage of R513A as a Substitute for R134a in a Vapor Compression Refrigeration System
No full textIn this study, the usage of alternative refrigerant R513A instead of R134a in a mechanical vapor compression refrigeration system was experimentally investigated in terms of thermodynamics. The investigations within the scope of this study were carried out at various (-5, 0, and 5 ℃) evaporation and (40, 45, and 50 ℃) condensation temperatures and constant approximately 10 kW cooling capacity without any modifications to the system. To determine the effects of refrigerants on the system performance were compared to each other the mass flow rate, required compressor electrical power, heat rejection rate from condenser, and Energy Efficiency Ratio (EER) in systems with both R134a and R513A. As a result, it was observed that the system worked safely in case of the usage of R513A without any modification instead of R134a. Consequently, it was determined that the mass flow rate increased by 18.08%, required compressor electrical power increased by 6.19%, heat rejection rate from condenser increased by 1.95%, and EER value decreased by 5.84% in the system using R513A compared to the system with R134a at 0 °C evaporation and 45 °C condensation temperature
Thermal Analysis of the PFC Circuit Inductor
No full textRectifier circuits with power factor correction have been developed for clean operation of rectifier circuits. In active power factor correction circuits, the input current of the rectifier is controlled and a sinusoidal current is drawn from the source. The inductor current of active power factor corrector circuits contains ripples. These ripples are caused by the switching of the converter. The switching frequency has a significant effect on the inductor current. The frequency of the ripples in the inductor current is equal to the switching frequency, while the amplitude is inversely proportional to the switching frequency. In this case, some thermal loss occurs due to a high frequency magnetic flux flowing through the inductor core. Since the switching frequency has an effect on both the frequency and amplitude of the ripples, it has a significant effect on the thermal losses of the inductor. In this study, the thermal losses of a booster rectifier circuit inductor using average current technique were analyzed using ANSYS/Maxwell program at 25, 40 and 50 kHz switching frequency values for three different inductor designs
Sliding mesh model application of a 2d design using computational fluid dynamics used in wind farm modeling
No full textThe participation of renewable energy systems in electricity generation, especially wind energy, has increased in recent years. Grid codes have been developed to ensure voltage and frequency stability of the electrical grid. Modeling and simulation of wind power plants (RES) play a very important role in the planning phase in terms of meeting grid connection criteria. In our study, a model study related to the application of sliding mesh in modeling the behavior of air movements in 2D blade geometry using computational fluid dynamics is presented
Experimental Investigation of the Usage of R513A as a Substitute for R134a in a Vapor Compression Refrigeration System
No full textIn this study, the usage of alternative refrigerant R513A instead of R134a in a mechanical vapor compression refrigeration system was experimentally investigated in terms of thermodynamics. The investigations within the scope of this study were carried out at various evaporation and condensation temperatures and constant cooling capacity without any modifications to the system. To determine the effects of refrigerants on the system performance were compared to each other the mass flow rate, required compressor electrical power, heat rejection rate from condenser, and Energy Efficiency Ratio (EER) in systems with both R134a and R513A. As a result, it was observed that the system worked safely in case of the usage of R513A without any modification instead of R134a. Consequently, it was determined that the mass flow rate increased by 18.08%, required compressor electrical power increased by 6.19%, heat rejection rate from condenser increased by 1.95%, and EER value decreased by 5.84% in the system using R513A compared to the system with R134a at 0 °C evaporation and 45 °C condensation temperature and 10.86 kW cooling capacity.
 
A New Approach Thermal Management System in Drying Oven
No full textUsing a heat pump in drying ovens is a widely adopted method to achieve more efficient drying processes. Heat pumps enhance the moisture extraction capacity of air, leading to faster and more efficient drying. Additionally, heat pumps recover the released hot air during the drying process, resulting in energy savings and reducing the cost of drying. In this experimental study, a geometry was designed for a drying oven integrated with phase change material (PCM), which has not been widely applied in the literature. The mechanical heating system in the drying oven employs a series-mounted condenser and a parallel-mounted evaporator system (SCPEDS). The experiments investigated three different scenarios for an ambient temperature of approximately 294 K and a drying oven air temperature of 323.15 K. The scenarios were conducted for three different drying air velocities; 0.50 m/s, 0.75 m/s, and 1 m/s, respectively. The experiments analyzed the effect of compressor on/off periods on energy consumption. The obtained data revealed that the most efficient scenarios, in terms of compressor on/off durations, were scenario 3, scenario 2, and scenario 1, respectively
Additive Manufacturing Impact on Fluidic Oscillator Energy Efficiency
No full textThe present research compares the impact of surface characteristics on the performance of additive-manufactured actuators versus conventionally milled samples. The major result is that the tested actuators with surface roughness Sa<20µm feature a bifurcated velocity profile for the incompressible flow. For the 3D-printed actuators for m>6g/s, the jet external properties were affected drastically. The increased roughness drastically impacts the sweeping jet spreading, and energy efficiency drops by 25%. The diminished sweeping jet spreading due to the surface finish eventually affects the heat transfer and emissions characteristics
Weight Stigma and University Media: A Pilot Study of College Student Perspectives of Body Messaging Using Photovoice
No full textNon-inclusive media images of and text pertaining to people with higher body weights can perpetuate weight stigma. This qualitative study explored the college student’s perspective of body messaging at a public university. Body messaging included images of people and text found within university print materials and social media platforms. We engaged a sample of seven participants, all of whom self- identified as a person of larger body size. The photovoice method was used for data collection where participants collected photographs of body messages the university included on print materials and social media platforms. Participants then completed an online questionnaire composed of open-ended questions about each photo. By using photovoice, we discovered the body messages participants found worthy of capturing. From the 27 photovoice body messages, over 40% did not have size diversity or if they did, they were placed in non-prominent locations on campus. Participants reported feeling excluded and hidden by the non-weight inclusive messages. Results from this study suggest that university body messaging may be part of the experience of weight stigma. Recommendations are provided for universities on how to promote weight inclusive environments through body messaging found in policy, programs and practice
Mindful practices in higher education classrooms: Impact on student experiences
No full textIncreasingly, research reveals that higher education students identify perceived stress and anxiety as negatively impacting their personal wellbeing, academic success, and future professional lives. Introduction of mindful practices into higher education settings has been shown to mitigate such stressors, and when practiced regularly, can enhance students’ sense of peace and calm. However, little is known about how students experience the introduction of faculty-led mindful practices in the classroom. As part of a larger mixed-methods study, university students were introduced to mindful activities by faculty, who incorporated these activities in their classrooms. Students were then invited to complete an online survey about their experiences. Student responses (n=45) reflected an overall positive experience of engaging in mindful practices in the classroom. Specifically, students identified benefits to self-care, sense of personal wellbeing, as well as reduction in perceived stress and anxiety. They also felt mindfulness increased their self-awareness and reflexivity and was transferable to personal and professional life-contexts. Students’ written comments about faculty-led mindful practices highlighted perceived benefits, such as improving focus and ability to absorb information, as well as challenges resulting from disruptive behaviours by classmates. Qualitative data collected from faculty suggest reduced student anxiety and increased self-care, as well as enhanced quality of faculty-student relationships and faculty teaching practices. Given the potential benefits of mindful practices for students, faculty may wish to explore strategies for introducing mindful activities into their classrooms in ways that support students who wish to participate, while allowing others to opt out in a respectful, non-disruptive manner
Receipts and Receipts NB: Critical Experiments in Mediated Testimony
No full textThis paper reports on two iterations of our ongoing Receipts project. The project serves as a means to experiment with and propose processes that use social practice and machine learning technologies to prepare testimonies and listeners to more clearly and impactfully speak, hear, and feel what it is like to respond to mimetic trauma and be part of an equity-deserving group in public space. The work is guided by the following question: How can the process of facilitating the preparation and presention of anonymized testimonies of discriminatory aggression in public spaces with the witnesses and victims of said agressions create structures of accountability, solidarity, healing, and community?
The first project, Receipts (2020), was presented as part of The Bentway’s Safe in Public Space program in Toronto, and addressed anti-Asian aggression in public spaces. The second project, Receipts NB, in collaboration with ArtFix, an organization that works with artists with substance abuse and mental health lived experience in North Bay, will address the stigmatization and isolation of this community during the pandemic. It will be presented as part of IceFollies 2023, a week-long public art festival on frozen Lake Nipissing.
These explorations emerge from and reflect upon a theoretical framework that connects visual culture, data creation, visual perception, cognition, machine learning processes, human-computer interaction, social practice and a practice-based framework for research-creation. The work is also informed by an approach to technoscience that uses a critical race, feminist, and decolonial lens. A necessary component of this framework is to prioritize equity through an emphasis on critical pedagogy, co-creation, and participatory art and design practice.
The critical media art practices and processes of Receipts do not aim to replace identifying video as an important means of holding people accountable. Instead, we hope that the project can shape technical, social, cultural practices of testimony and listening and make collectivized community resistance resonate more deeply.
We also reflect on how computer vision and artificial intelligence tools increasingly deployed as part of “smart city” infrastructures have been proposed as a means to address these issues in real time by predicting, identifying, and aggregating transgressions. Yet, in practice, these tools lack nuance, approximate and automate-out the importance of relationship building with communities, and have generally been used to identify patterns and build predictive surveillance that disproportionately disadvantages already discriminated-against groups. We hope that Receipts can serve as an example of how to engage the potentials of urban technology while also highlighting some of its pitfalls
Exploring Interactivity in Digital Comics: A Multifaceted Analysis of Sequential Storytelling
No full textThe digital revolution has reconditioned our media landscape, instigating hybridity in traditional forms and reshaping the nature of storytelling through enhanced interactivity. This paper scrutinizes the transformative interplay of digital technologies and comic books, engendering new media narrative forms such as interactive comics and redefining conventional sequential storytelling. As a reflection of this evolution, comic books, long recognized as sequential art, have broadened their narrative scope by integrating elements of motion, interactivity, and game-like attributes.
This research explores four distinct types of digital comics: Meanwhile: An Interactive Comic Book (Zarfhome Software, 2018), Framed (Noodlecake Studios, 2014), Florence (Mountains Studio, 2018), and Our Plague Year (Burton, 2022). By adopting Sheldon’s categories of interactivity and Lebowitz and Klug\u27s interactive story spectrum, we analyze these stories\u27 levels of interactivity and linearity. The findings indicate that the complexity, diversity, and multitude of reader agency do not necessarily render a story interactive in terms of content. While these digital comics vary significantly in design, most still adhere to a traditional linear narrative framework despite the diversity and many interactive elements. Only “Meanwhile: An Interactive Comic Book” deviates from linearity, manifesting non-linear, web-like narrative structures and branching story paths.
This analysis unravels the nuanced hybridization of digital media and comic books, illuminating how digital technologies reshape and augment our narrative practices. The digital revolution has not only brought about a new storytelling habitat but also expanded our understanding of co-authorship, thus pushing the boundaries of sequential storytelling in an ever-evolving digital culture.
It also highlights the importance of recognizing the differences between interacting with the medium and interacting with the story itself. Consequently, this research contributes to the understanding of the intricate relationship between digital technologies, interactivity, and sequential storytelling, paving the way for further exploration in the field of digital comics.