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Diffusion-driven aggregation of particles in quasi-2D membranes
Get PDFMany biological membranes can be modeled as two-dimensional (2D) viscous fluid sheets surrounded by three-dimensional (3D) fluids of different viscosity. Such membranes are dubbed quasi-2D as they exhibit properties of both 2D and 3D fluids. The Saffman length is a parameter that describes the energy exchange between the membrane and bulk fluids and controls the cross-over from 2D to 3D hydrodynamics. We aim to model diffusion-driven aggregation of particles embedded in a quasi-2D membrane. It is known that hydrodynamic interactions between solute particles significantly reduce their aggregation rate in 3D fluids. It is expected that in quasi-2D membranes the reduction of the aggregation rate will be even more pronounced due to a slower spatial decay of hydrodynamic interactions in 2D. We perform computer simulations to study the aggregation rate of solute particles as a function of the Saffman length
Notification System for Unity OpenXR
Get PDFAs the field of digital media continues to advance, innovative ways of experiencing and interacting with entertainment content are emerging. One such groundbreaking development is the advent of interactive entertainment, where virtual environments become the canvas for immersive experiences. In this realm, I have joined a captivating project that harnesses the power of Unity to create a virtual reality (VR) chemistry laboratory. This project is designed to revolutionize the way chemistry experiments are conducted by providing a realistic and engaging virtual environment. In the real world, there are many reasons why school-age middle or high school students may not be able to fully experience a chemistry lab, either because some are homeschooled, or perhaps because schools don\u27t have enough funding, or don\u27t give chemistry labs enough attention, or are simply concerned about the safety issues that may arise. Another is that students may not be able to understand why chemical reactions occur the way they do because of visibility limitations or because they are influenced by the materials used in the experiment. Leveraging the capabilities of Unity, we are crafting a dynamic platform where multiple chemistry experiments can be simulated with precision and interactivity. This cutting-edge endeavor allows users to step into the shoes of chemists, immersing themselves in a digital laboratory where they can perform a wide range of experiments
Design, Modeling, and Testing of a Novel Inductor for Electric Vehicles: Iron Nitride Soft Magnetic Composites
Get PDFNew technology for electric vehicles (EVs) must meet the requirements of higher energy usage, lower costs, and more sustainable source materials. One promising material for EV power system components is iron nitride (IN) soft magnetic composites (SMCs) because of their competitive magnetic properties and high abundance of the source materials. As part of an ongoing program at Sandia National Laboratories, this project focused on using computer modeling to optimize the prototyping process for an iron nitride SMC toroidal inductor to reach a target inductance of 600 μH. Four inductors with different combinations of wiring (26 AWG and 20 AWG) and vol% loading of iron nitride (65 vol% and 50 vol%) were fabricated at Cal Poly and characterized using an LCR meter. These inductors were also modeled using COMSOL Multiphysics™ with the Magnetic Fields module. The inductance data from the experiment and the model show that the 65 vol% IN prototypes and models agree with about 8% difference, while the 50 vol% IN samples show about a 9% difference between the prototype and the model. These results suggest that the model can predict inductance with both accuracy and precision with low confidence for the given sample size of four. An additional parameter of AC resistance is studied but the AC resistance results from the inductors and from the model generally do not agree closely, suggesting that the current model used in the project does not fully capture the mechanisms behind AC resistance of the inductor. With the focus of the project on inductance, the percent difference results of less than 9% across the four inductors that were tested increases confidence in the model’s predictive capabilities for inductance only. Using the inductance results from both the model and experiment, the final suggested inductor design is a 65 vol% core with 150 windings of 20 AWG wire that is 8 cm across and 1.5 cm tall to reach the inductance goal of 600 μH based on analysis using the optimized COMSOL™ model
Adaptive Fascism: A Study of Far-Right Politics in the Americas
Get PDFPopulism as a term is too ambiguous to describe the surge in far-right nationalistic leaders both during the Cold War and the present day. This paper proposes to solve this quagmire by proposing the term adaptive fascism. Adaptive fascism is the idea that far- right leaders using tactics that have legacies within fascist rhetoric have adapted the fascist rhetoric to fit more within the geopolitical situations of each leader’s respective time period. Looking at both leaders of the Cold War, including Jorge Videla of Argentina and Augusto Pinochet of Chile. As well as modern day leaders, Donald Trump of the United States and Nayib Bukele of El Salvador, to show that fascism is not static and rather it is a living breathing ideology with the ability to adapt and shift to fit into the crises of different periods in geopolitical history
California\u27s Native Trees and Their Use in the Urban Environment
Get PDFCalifornia’s urban forest is composed of both native and non-native species. These trees improve the quality of life of urban residents and mitigate the effects of climate change by buffering local microclimates. A species’ native status is often defined at the scale of the state’s political boundaries, which doesn’t reflect its actual native range. Here we define the list of 95 tree species native to California, create digital range maps for each species, provide native species lists for every city in California, and analyze trends in native tree species in the state’s urban areas. We found that California’s urban areas have relatively few tree species that are native within a given city’s boundaries. Even though non-natives outnumber natives in all California cities, opportunities for more native tree diversity are slim as most cities have less than four native species that aren’t already growing as urban trees. California’s cities face a hotter and drier future, threatening existing urban forests and the benefits they provide residents. We explore different options for tree selection based on the goal of growing healthy and resilient urban forests into the future
The Temporal Evaluation of Mouthfeel and Retronasal Sensations in Red Wines from the Central Coast of California
Get PDFTime-based sensory analysis techniques capture the dynamic retronasal and mouthfeel sensations in wines. It is important to understand how common winemaking practices and popular varietals impact the retronasal and mouthfeel profile as consumers tend to judge wine quality based on the taste, flavor, and mouthfeel of a wine. Three time-based sensory analysis methods were utilized with the objective to understand the effect of five commonly applied winemaking techniques (blending, varietal choice, fermentation temperature, cap management, and stem addition) on the dynamic retronasal and mouthfeel profile of six different varietals (Merlot, Malbec, Petite Sirah, Pinot noir, Grenache, and Tannat) grown on the Central Coast of California. An additional objective was to account for panelist salivary flow rate and its impact on the time and rate of perception of astringency and selected retronasal aromas during time-based evaluations. Finally, as descriptive analysis was employed in three of the studies to assess color and orthonasal aroma, which is an effective static method but requires a lot of training time, the use of a rapid method known as Pivot© Profile was utilized to assess Syrah wines from the Central Coast of California.
Temporal Dominance of Sensations (TDS) was utilized to determine if there were significant differences between cofermented and blended wines as well as the impact of varietal choice. TDS curves (n=11) demonstrated that varietal choice was more impactful on the retronasal profile than blending time. Chemical analysis indicated that post-malolactic fermentation wines had higher titratable acidity, while cofermented wines had higher tannins. Indeed, the differences between blending times were subtle but were reflected in the TDS curves. Therefore, it was recommended to employ post-alcoholic or post-malolactic fermentation blending over cofermentation. TDS was also utilized to understand the impact of whole cluster, stem addition, and wine sipping volume on the temporal sensory profile of Tannat wines. Similar to the previous study, TDS curves (n=10) were able to reflect differences in astringency, acidity, and hot perception which were apparent in basic and phenolic chemistry. Indeed, the combination of Tannat and stem addition led to wines with a long (34.6 seconds) perceived dominance of astringency. Volatile chemistry indicated that the use of whole cluster in Tannat wines led to higher concentrations of phenylethyl alcohol, β-damascenone, and the terpene, trans-farnesol, compared to the control, and other stem addition wines. Therefore, it was recommended to explore whole cluster addition in Tannat for future research over the green and dried stem wines.
Time-Intensity (TI) and Temporal Check-All-That-Apply (TCATA), were utilized to understand the effect of alcohol fermentation temperature and cap management regimes in Pinot noir and Grenache wines. TI results (n=13) suggested that fermentation temperature had more of an impact on the mouthfeel and retronasal profile of Pinot wines than cap management. Indeed, while Hot fermentation temperature wines led to more intense astringency perception relative to the other treatments, Cold fermentation temperature wines led to higher perception of retronasal flavor which was also reflected in the volatile chemistry. As for Grenache, the results were more complicated as this variety was sensitive to both oxidation and reduction aromas. TCATA (n=8) and volatile chemistry results indicated that the treatment with the most balance of retronasal fruit and astringency with minimal reduction flavor were the Cold/Hot PD wines. The results of both studies suggested that both fermentation temperature and cap management regime were indeed varietal dependent.
When using time-based sensory analysis, it is important to account for salivary flow rate, an inherent physiological characteristic, that affects the time and perception of astringency and retronasal aromas. Past research has utilized TI to examine this phenomenon, whereby low salivary flow rate individuals typically perceived astringency later and more intensely than high salivary flow rate individuals. For retronasal aromas, it depends on the associated volatile compound. For example, fruit aromas which are associated with esters are typically perceived by high salivary flow rate individuals as later and more intensely than low salivary flow rate individuals. Since tracking salivary flow rate has been exclusively used in TI, methods were developed in the present study to examine the time of first dominance in TDS and time of first perception in TCATA. Throughout each study, the pattern of astringency perception followed previous reports with two exceptions. In the Pinot noir wines, higher salivary flow rate panelists had their time of maximum intensity later than low salivary flow rate panelists. However, the time of first perception, maximum intensity, and area under curve were still significantly later and higher in low salivary flow rate panelists. With the Tannat wines, high salivary flow rate individuals had significantly later time of dominance for astringency than low salivary flow rate panelists. In this case, it was thought to be because only one parameter was being assessed for this pattern whereas the inclusion of area under curve or maximum citation proportion by group may provide more information.
Finally, the use of a modified Pivot© Profile with an expert panel (n=15) was examined in Syrah wines that underwent different cap management and maceration techniques as well as different ethanol levels. Results indicated that modified Pivot© Profile was effective for differentiating color and orthonasal aroma attributes by cap management style. However, modified Pivot© Profile was not able to reflect the differences seen in the basic and volatile chemistry specifically the effect of ethanol level on malolactic fermentation. Therefore, it was recommended to use modified Pivot© Profile for color and orthonasal aroma but employ a time-based sensory method for understanding the retronasal and mouthfeel profile as it can reflect differences in chemistry more effectively.
Overall, the employment of time-based sensory analysis to examine the dynamic retronasal and mouthfeel profile in red wine was worthwhile, as these methods can subtly reflect differences in chemistry as well as assist in making practical winemaking decisions
Mechanical Metamaterials
Get PDFMechanical metamaterials are an emerging design strategy aimed at tailoring lattice structures to achieve specific properties such as negative Poisson’s ratios and guiding wave propagation. These metamaterials have received increasing attention from various application domains, including medical devices, aerospace, automobile, and infrastructure. The scope of this project is to vary a single lattice parameter and quantify its effect on the structural properties of the given 3D lattice
The Perceptions and Effects of Nutrition on Worker Health and Productivity in Construction
Get PDFConstruction workers often have poor dietary habits due to poor nutrition education, lack of nutritious food options, and social stigma. These habits often lead to health problems like obesity, diabetes, and heart disease which can decrease productivity and put workers at risk of on-site injury. This preliminary study examines how nutrition impacts worker safety and productivity. A survey was distributed to six students involved in construction work for Cal Poly’s Residential Construction course. This survey identified their eating habits and inhibitors for healthy eating. Two meals, one with high nutritional value and one with low nutritional value, were given to the students before performing construction work. The students then filled out a survey rating their perceived levels of safety, alertness, and productivity. Results indicated that students who ate the healthy meal averaged 2.6% lower for safety, 10.6% higher for alertness, and 13.4% higher for productivity than those who ate the unhealthy meal. This aligns with research showing that diets low in fruit and vegetable intake and high in sodium can lead to decreases in productivity. Findings of this study could be applied in the field to improve worker diets, which would lead to increases in alertness and productivity
