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Power Transmission System Demo
Get PDFProfessor Ramanan Sritharan and ME 329 students need a high-quality Power Transmission System, a detailed report, and robust Excel spreadsheet including all calculations that can serve as an example for students in the ME 329 lab
Hydropower Collegiate Competition
Get PDFThe Cal Poly SLO HCC team presents a feasibility study and engineering design review package for retrofitting the non-powered Ritschard Dam in Colorado into a hydroelectric facility as part of the 2025 Hydropower Collegiate Competition. Through a rigorous and multi-staged assessment of plausible dam sites in the western US, the team has chosen the Ritschard Dam in Colorado to implement an electromechanical component designed to accommodate a large range of flowrates stemming from a large variance in upper reservoir capacity due to geographical and climate effects. The team evaluated non-powered dams based on technical feasibility, electric grid proximity, power generation potential, environmental considerations, economic potential, and regional energy goals. Following this initial screening, a weighted design matrix approach was used to score prospective dams against one another using the criteria along with risk and safety considerations and societal effects. Among the final candidates, the Ritschard dam stood out for its high-power generation potential (5.7 MW), sub 1 mile proximity to the electrical grid, and alignment with the ambitious Colorado state climate plan aiming to eliminate carbon emissions by employing 100% renewable energy sources by 2040. The dam primarily serves to supply downstream communities and agricultural entities with a stable water supply but contains infrastructure to incorporate power generation equipment, representing a fantastic opportunity to bolster Colorado’s renewable energy supply. During the summer months the Ritschard dam has an excess of 68,000 acre-feet of active water storage supplied by snowmelt from the Wolford Mountain. A hydraulic height of 122 feet allows for a maximum generation potential of 5.7 MW. In the winter months, that level of active water storage dips to 53,000 acre-feet, representing a huge potential loss in energy generation potential. This change in reservoir storage necessitates an adaptive hydroelectric facility that can preserve the agricultural water supply and make use of all excess water for energy generation. Wicket gates, or guide vanes, add directionality, control flow, and allow for hydropower turbines to operate at their most efficient point. This component addresses the key climate driven challenges at the Ritschard Dam. To justify the implementation of a wicket gate assembly to the Ritschard dam, the team utilized a MATLAB Simulink simulation, modeling a PID controlled wicket gate system that dynamically adjusts flow rates and synchronized power output. Virtual testing such as finite element analysis was conducted on the wicket blades, as well as kinematic studies of the assembly linkage to validate the design’s structural integrity and ensures the component is fit to operate under steady state conditions. A scaled prototype was created and tested, demonstrating autonomous control in response to user inputted flow rates simulating the various input flow as seen on a monthly basis at the Ritschard Dam. Risk assessments were conducted to address operational, structural, and environmental concerns with the design and suggest mitigation strategies like increased monitoring, mechanical redundancy and electrical bypass systems. By leveraging existing infrastructure and incorporating autonomous control systems, the team has proposed an economically viable, low impact solution that would expand Colorado’s renewable energy supply
Combustion Liner Optimization
Get PDFSolar Turbines provides gas power generation solutions, focusing on gas turbine engines and compressors. The Gas Turbine Products Engineering (GTPE) team at Solar Turbines needs a way to efficiently and cost-effectively maintain the combustion liner of the Taurus model gas turbine at or below the cold-side temperature target. The current system involves a manufacturing process with ergonomic concerns and uncertain cooling effectiveness.
To address this, our team proposed a new combustion liner system featuring impingement cooling. We provided Solar Turbines with heat transfer models of both the existing and proposed designs, demonstrating improved cooling performance. Additionally, a prototype of the proposed solution was manufactured and tested to validate the design
Improvements to Cal Poly\u27s Hybrid AC/DC House
Get PDFThis senior project details the improvements made to Cal Poly’s Hybrid AC/DC House project. The previous state of the house experienced issues with proper reading of the current power being drawn from the connected AC sources, as well as with the system’s multiple-input single-output converter, where thermal overheating of specific FETs prevented the system from reaching its maximum output power. The updates made to the AC/DC house include improved code to prevent faulty readings and display failure and a cleaned-up power monitoring board that removes noisy signals and allows for the correct power implementation to be displayed. In addition, the MISO implements additional ground planing, as well as an adjustment to the board FETs by adding gate resistance to reduce noisy signals and selecting transistors with a lower drain-source resistance to reduce losses and heat generation. Results of the power management system include fully monitorable AC and DC power metrics displayable on a touchscreen, as well as breadboard circuitry that removes the common ground faults present in the original design. The MISO board shows proper operation with a single parallel supply up to 400W with 98% efficiency, as well as proper operation with dual supplies up to 300W with 99% efficiency. Additionally, the operation of these boards reduces the full-load operation temperature after ten minutes of continuous power delivery from that of the previous design
Lab Building with Atrium
Get PDFThis report includes a prescriptive and performance-based analysis on a university life sciences building hereafter referred to as “Lab Building”. The code-based analysis includes the review of the following components: Occupancy classification and construction type, Egress, Control areas, Structural fire protection, Fire alarm and fire sprinkler systems, and Smoke control.
The Lab Building is of type IB construction and is four stories above grade with one story below grade. The building uses a non-separated mixed occupancy approach with Group A- 3 bring the most restrictive occupancy classification. Additionally, the building is fully sprinklered with a fire alarm and emergency voice alarm communication system and an atrium smoke control system.
A performance-based analysis was also conducted to analyze the smoke control system within the building’s atrium and determine if an appropriate design fire would overwhelm the system and conflict with the building’s life safety strategy. Pathfinder and Fire Dynamics Simulator (FDS) models were used to estimate the building’s available safe egress time (ASET) afforded to occupants to compare with the required safe egress time (RSET).
The two design fires analyzed in the performance-based analysis include an axisymmetric plume fire (Design Fire 1) and a balcony spill plume fire (Design Fire 2). Design Fire 1 was located on the atrium floor directly beneath the atrium opening and grew to 5,300 kW in 194 seconds. This fire assumes the sprinklers at the atrium roof do not activate due to an expected low smoke temperature at that height.
Design Fire 2 was located on the first floor underneath the second floor slab where sprinklers are provided. The closest sprinkler head activated 118 seconds which corresponded to a peak heat release rate of 1,908 kW.
Both design fires have a significant fuel package that is larger than what would be expected in the atrium floor to indicate why atrium floors are prescriptively permitted to only contain low hazard fuels. The results reveal that the chosen fuel package yields a significant amount of smoke production which overwhelms the smoke control system. As a result, the time to untenable conditions occurs before occupants can safety evacuate. The quantitative results are summarized as follows:
Design Fire 1: Level 4 had the largest RSET of 397 seconds with no safety factor and an ASET of 128 seconds. The net difference observed between the RSET and ASET was smaller for Levels 2 and 3.
Design Fire 2: Level 4 had the largest RSET of 442 seconds with no safety factor and an ASET of 423 seconds. A larger net difference of approximately 100 seconds was observed between the RSET and ASET for Levels 2 and 3.
As previously mentioned, the chosen design fire fuel load is much larger than what would be present on the atrium floor. This substantiates why the code does not allow high fuel loads to be provided on an atrium floor
Studies on the Effects of Cap Management on the Oxidation–Reduction Potential, Phenolic Composition, and Sensory Properties of Red Wines
No full textCap management during alcoholic fermentation of red wines plays a critical role in modulating the phenolic and volatile extraction from grape solids, influencing the homogenization of chemical and temperature gradients, while imparting oxygen to the must. Different cap management alternatives are also thought to influence the evolution of the oxidation-reduction potential (ORP). It is critical to understand how different cap management protocols affect these variables to design a cap management protocol tailored to wine style and varietal. This thesis investigated the effects common commercially applied cap management protocols, as well as the efficacy of novel, automated gas mixing protocols as potential alternatives to labor-intensive cap management. Additionally, this research sought to investigate how some specific and contrasting phenolic and chemical makeup between grape varietals may respond to varying cap management protocols.
In the 2023 and 2024 vintages, contrasting cap management protocols were applied to Pinot noir and Petite Sirah wines from the Central Coast of California. These include the commercially traditional protocols of punch-downs and pump-overs, as well as no cap management with and without various automated air or nitrogen gas mixing regimes. The ORP was monitored during alcoholic fermentation of the gas mixing wines of the 2023 vintage, and all wines of the 2024 vintage. The results detailed how cap management regimes can be designed to produce targeted ORP evolutions. Additionally, the results detailed the effects of these protocols on the phenolic and volatile composition of the wines.
In the 2023 vintage, Pinot noir and Petite Sirah wines were produced with the following cap management protocols: punch-downs (PD), pump-overs (PO), no cap management (NoCapMgmt), and two gas mixing protocols, whereby air or nitrogen (N2) gas was injected into the bottom of the fermentation vessel for 1 h, twice daily, (AirMix; N2Mix). These varietals were chosen as representations of how wines of typically low (Pinot noir) and high (Petite Sirah) phenolic potential may respond differently to contrasting cap management protocols. ORP of AirMix wines reached peaks of 340 mV and 240 mV in Pinot noir and Petite Sirah, respectively, while N2Mix wines were consistently below −50 mV during alcoholic fermentation. At pressing, PD wines contained more total phenolics than PO wines in Pinot noir, but not in Petite Sirah. However, PD wines of both varietals in the 2023 vintage increased flavan-3-ol concentrations when compared to all other treatments. NoCapMgmt wines contained \u3e50% increases in esters, when compared to PD wines, revealing the effects of physical mixing on CO2 stripping of volatiles. Of all volatiles, the largest differences were seen in isoamyl acetate. AirMix wines showed decreased astringency and increased red fruit character, while N2Mix wines had higher color saturation as perceived by sensory analysis. Neither AirMix nor N2Mix wines showed detectable reductive aromas at 3 months of bottle aging despite receiving no cap management other than gas injections.
In the 2024 vintage, Pinot noir and Petite Sirah wines were produced using five and six cap management protocols, respectively: PD; PO; AirMix; and N₂Mix; as well as ORP-control through air injections triggered by ORP measurements ≤-40 mV (RedoxConAir), and, in Pinot noir only, N2 additions paired to inject gas simultaneously with respective RedoxConAir replicates (RedoxConN2). ORP, reduced glutathione (GSH), and oxidized glutathione (GSSG) were monitored throughout a 10-day alcoholic fermentation in all wines. This study revealed the temporary effects of oxidative pump-overs on the ORP of wine. PO wines exhibited peaks in ORP of ≥100 mV during pump-overs, whereas PD wines increased 20-40 mV during punch-downs during peak fermentation. At pressing, the ratio of GSH:GSSG was correlated with the prevailing ORP of the wines before pressing (p\u3c 0.04), suggesting the glutathione redox couple is an effective marker of the oxidative or reductive history of a wine. AirMix wines showed similar phenolic losses to the 2023 wines. In further continuity with the 2023 vintage, PD wines extracted more flavan-3-ols, and wines with the least physical mixing and degassing (2023, no cap management; 2024, RedoxConAir) retained significantly more esters, namely, isoamyl acetate.
Collectively, these findings confirm that different cap management protocols distinctly affect the ORP of wine fermentations, and in turn affect their chemical makeups. Gas injection protocols can serve as viable, automated alternative or supplementation to manual cap management in cases of favorable fermentation size and geometry. Differences in phenolic response between Pinot noir and Petite Sirah underscore the importance of varietal context in designing a cap management protocol. However, the ORP does not appear directly related to the oxidation or extraction of phenolic compounds and alternatively is better suited as a tool to regulate volatile sulfur compound production and yeast performance. Lastly, automated gas mixing systems present an opportunity to design fermentation strategies that align with stylistic goals while improving efficiency and consistency in wine production
Plastic Microfibers Impact the Immune System of the Pacific Oyster
No full textMicroplastics (MPs) (plastics \u3c 5 mm in size) are widespread pollutants in marine environments and pose a threat to marine organisms through ingestion or environmental exposure. Our previous research showed that the Pacific oyster (Crassostrea gigas) from Morro Bay Estuary harbor moderate amounts of microplastics, primarily microfibers (MFs), in their gills and digestive glands. While prior studies have demonstrated that microplastics can impair oyster reproduction, growth, metabolism, and survival, the impact of MFs on the immune system of C. gigas remains unexplored. Therefore, we explored whether MFs can elicit an immune response in C. gigas. To address this, we exposed oysters to three environmentally relevant concentrations of MFs (0.0076 MF/mL, 0.015 MF/mL, 0.031 MF/mL) over two weeks. Hemolymph from the pericardial cavity and digestive gland and gill tissue samples were collected to test the hypothesis that MF ingestion would trigger immune responses. We predicted a dose-dependent increase in MF accumulation in tissues, elevated hemocyte counts, and increased lysozyme activity. Our findings confirmed that oysters ingested MFs, with significantly higher concentrations found in gills (1.3358 MFs/g wet weight ± 0.184) compared to digestive glands (0.2043 MFs/g wet weight ± 0.184) (DF = 59; F = 18.8372; p = 0.00003). MF exposure led to a significant, dose-dependent increase in total hemocyte counts in hemolymph (DF = 148; F = 18.4289; p \u3c 0.0001). However, lysozyme activity significantly decreased following MF exposure (DF = 69; F = 6.9264; p = 0.0004), with reductions observed at both the lowest and highest concentrations, but not at the intermediate level. These results indicate that C. gigas ingest MFs, which accumulate primarily in the gills, and that such exposure induces a measurable immune response, characterized by increased hemocyte production and suppressed lysozyme activity. The complexity of this immune response underscores the need for further studies to evaluate how MF exposure may affect the overall health, growth, and reproductive success of C. gigas and other marine species
Direction Finding from Aerial Platforms with Amateur Radio Arrays
Get PDFThis senior project presents the development of a communication network designed to remotely control and program a distributed digital antenna array for autonomous synchronization and calibration. The system facilitates command transmission using a custom BPSK communication protocol operating in the UHF band (430–450 MHz) and employs a two-tone waveform to extract frequency, phase, and timing offsets between array nodes. These offsets are critical for aligning received signals in preparation for digital beamforming. The array comprises four nodes: three aerial units and one ground-based control unit. Each node is built using a LimeSDR Mini 2.0, Raspberry Pi, portable battery pack, and powered USB hub. GNU Radio is used to construct and manage the BPSK and two-tone signal chains, while higher-level Python scripts implement a finite state machine to coordinate timing, control logic, and data exchange. This system represents the foundational hardware layer for a larger multi-year project focused on implementing cost-effective, software-defined digital beamforming arrays. This research not only presents a novel implementation of distributed digital arrays but also enhances target localization accuracy through the creation of a coherent and calibrated digital beamformer. The findings have the potential to significantly improve the performance of distributed arrays in critical applications such as disaster response, defense, and other scenarios where access to nodes is limited
“Aquellos Que Reputan Todos Por Españoles”: Conflicting Historical Ideologies Regarding Race in Nineteenth Century California.
No full textCalifornia has a rich and diverse history marked by various communities. From its Indigenous peoples to the significant influx of immigrants in the nineteenth and twentieth centuries, the state has embraced individuals from a wide range of cultures. However, one often-overlooked group is the gente de razón, or ‘people of reason,’ California’s earliest non- Indigenous settlers from Mexico in the eighteenth century. Many arrived for military service to assist Spanish missionaries, while others settled with their families, creating some of California’s vibrant towns. Despite being a smaller population compared to later immigrants, they left a lasting impact on place names, food, and culture. Recent research analyzing Spanish census records from the eighteenth and nineteenth centuries reveals a compelling narrative often overshadowed by romanticized views of California’s history. Notably, many gente de razón had mixed European, African, and Indigenous Mexican heritage during an era when racial hierarchies were beginning to form in Latin America and the United States. Their relative isolation in California may have shielded them from potential discrimination, but their diverse backgrounds ultimately melded into a collective identity known as the Californios. Intriguingly, after the United States gained control of California in the mid-nineteenth century, many Californios were categorized as “White” in U. S. Census records. Given the United States’ racially motivated strategies to maintain social hierarchies concerning African-descended individuals and Indigenous populations, it is notable that many Californios actively participated in government and were integrated into the expanding United States. Their wealth as landowners may have played a role in this integration, but it ultimately underscores how race is a social construct influenced by regional and contextual factors. This thesis aims to explore why the Californios were designated as such and how their historical and societal status in California shaped their identity in relation to the evolving concept of race over time
Assessment of the IMX7ULP Heterogeneous SoC for Use in a Next Generation Student CubeSat OBC
Get PDFCubeSats represent a rapidly evolving platform for space research, industry, and education, demanding increasingly sophisticated onboard computing solutions that balance performance, fault tolerance, size, weight, and power constraints. Although the design of the Cal Poly\u27s CubeSat Lab\u27s (PolySat) current On-Board Computer (OBC) keeps up with many of these factors, the demands of modern workloads like fine attitude determination will start to outpace available compute. While the selection of a more capable processor to address this would have traditionally resulted in increased energy usage, modern system-on-chip (SoC) architectures offer novel ways to trade available compute for power savings on-the-fly. With this motivation, the NXP i.MX7ULP SoC—a dual-core heterogeneous architecture featuring an ARM Cortex-A7 and Cortex-M4—is investigated for use in PolySat’s next-generation OBC. A performance and power trade study is conducted using an i.MX7ULP development kit, focusing on critical capabilities such as fault tolerance, power modes, cross-core communication, floating point arithmetic, and vectorization. The A7 and M4 cores are also individually characterized and assessed for software development ease. Results indicate that performance of this SoC can scale up to 15x that of the existing OBC while still being more energy efficient. They also showed the M4 core has the potential of reducing idle state power consumption by up to 53% of the current OBC\u27s by power-gating the other core. Additionally, worst case power consumption during intensive tasks remained under 480 mW. Cross-core communication overhead was also shown to be minimal and software development was found to be approachable using available software development kits (SDKs). The results of the investigation were applied towards starting the design of a software and hardware architecture that poises PolySat to handle the missions of today and the future