62970 research outputs found
Sort by
PDE Modeling of the Cooling Fluid Temperature in Battery Pack
Get PDFThis paper presents a comprehensive analysis of heat transfer in cooling systems for battery packs in electric vehicles (EVs). A cylindrical coordinate framework is employed to model the heat transfer equation, incorporating diffusion, convection, and heat sources due to electrochemical reactions in the cell. Boundary conditions are derived to account for radial symmetry and cascaded axial heat exchange across modules. The proposed model introduces a coupled nonlinear framework that dynamically interrelates fluid temperature, heat generation, and module temperature, effectively capturing transient and nonlinear thermal interactions
Empowering Families: Proposing Legislative Enhancement for Third-Party Special Needs Trusts in Texas Student
Get PDFThe article argues that the current statutory framework governing third-party special needs trusts (SNTs) in Texas is inadequate, failing to protect beneficiaries from mismanagement by trustees and align with the settlors' intent. It proposes specific amendments to the Texas Trust Code, including stricter language on income distributions, payback provisions, and trustee qualifications, to enhance beneficiary protections and maintain their government benefits eligibility. These changes aim to ensure long-term stability and accountability in SNT management
Executive Roundup: Saddling Private Article II Enforcement under the Horseracing Integrity and Safety Act of 2020
Get PDFExecutive Roundup: Saddling Private Article II Enforcement under the Horseracing Integrity and Safety Act of 2020 examines the constitutional structure of enforcement authority created by the Horseracing Integrity and Safety Act. It explains how the Act’s reliance on a private regulatory body raises questions under Article II concerning executive power, supervision, and accountability. The discussion situates the Act within Supreme Court precedent addressing private nondelegation and presidential control over enforcement. It also considers the practical consequences of insulating regulatory enforcement from traditional executive oversight. The abstract concludes by identifying constitutional tensions that may shape future challenges to the Act’s enforcement scheme
Risk-Adjusted Performance of Random Forest Models in High-Frequency Trading
No full textBecause of the theoretical challenges posed by the Efficient Market Hypothesis with respect to technical analysis, the effectiveness of technical indicators in high-frequency trading remains inadequately explored, particularly at the minute-level frequency, where the effects of the microstructure of the market dominate. This study evaluates the integration of traditional technical indicators with Random Forest regression models using minute-level SPY data, analyzing 13 distinct model configurations. Our empirical results reveal a stark contrast between in-sample and out-of-sample performance, with (Formula presented.) values deteriorating from 0.749–0.812 during training to negative values in testing. A feature importance analysis demonstrates that primary price-based features dominate the predictions made by the model, accounting for over 60% of the importance, while established technical indicators, such as RSI and Bollinger Bands, account for only 14–15%. Although the indicator-enhanced models achieved superior risk-adjusted metrics, with Rachev ratios between 0.919 and 0.961, they consistently underperformed a simple buy-and-hold strategy, generating returns ranging from −2.4% to −3.9%. These findings challenge conventional assumptions about the usefulness of technical indicators in algorithmic trading, suggesting that in high-frequency contexts, they may be more relevant to risk management rather than to predicting returns. For practitioners and researchers, our findings indicate that successful high-frequency trading strategies should focus on adaptive feature selection and regime-specific modeling rather than relying on traditional technical indicators, as well as indicating the critical importance of robust out-of-sample testing in the development of a model
The Chemical Fingerprint of Smokeless Powders: Insights from Headspace Odor Volatiles
No full textSmokeless powders are a commonly used low explosive within the ammunition industry. Their ease of purchase has allowed criminals to use these products to build improvised explosive devices. Canines have become a vital tool in locating such improvised devices. With differing fabrication processes, one of the most difficult challenges for canine handlers is the optimal selection of training aids to choose as odor targets to allow for broad generalization. Several studies have been underway to understand the chemical odor characterization of smokeless powders, which can help provide canine teams with essential information to understand odor signatures from powder varieties. In this study, a solid phase microextraction method optimization was conducted using unburned smokeless powders to provide a chemical odor profile assessment. Concurrently, statistical analysis using principal component analysis and Spearman rank correlations was performed to explore whether odor volatile composition depicted associations between and within powder brands. Results showed that a longer extraction time (24-hrs) was optimal across all powders, as this yielded higher compound abundance and number of extracted odor volatiles. The optimal SPME fiber varied per powder, depicting the complexity of powder composition. There were 66 common compounds among the 18 powders, including 2-ethyl-1-hexanol, diphenylamine (DPA), and dibutyl phthalate. Principal component analysis (PCA) depicted that while powders may be of the same type (single/double base), they can still portray clustering differences across and within brands, indicating variability. The Spearman rank correlation within powder type suggested that the double base powders had a slightly higher indistinguishability index when compared with the single base powder types
Removal of Ammonia from Urine Using Isotherm pH Dependent Membrane Distillation
No full textElizabeth del Rosario Salas-Sandoval, University of Guanajuato, MexicoMichael Flynn, National Aeronautics and Space Administration (NASA), United StatesICES303: Physico-Chemical Life Support- Water Recovery &
Management Systems- Technology and Process DevelopmentThe 54th International Conference on Environmental Systems was held in Prague, Czechia, on 13 July 2025 through 17 July 2025.The high concentration of ammonia in urine creates both
difficulties for water recycling and opportunities for
nitrogen recovery. Water recycling is needed in a
spacecraft to provide water for the crew and nitrogen is
needed to make up for cabin air lost through airlocks and
general cabin leakage. Membrane distillation (MD) can
recover volatile ammonia from hydrolyzed urine using an
isothermal membrane distillation with an acidic draw
solution. The isothermal operation suppresses water vapor
permeation while the pH difference across the membrane
creates a concentration gradient of ammonia that drives
flux from the feed side of the membrane to the draw side.
The feed is at a neutral to basic pH do the ammonia in it.
The draw solution is kept at a low pH (<5) which shifts the
equilibrium between ammonia and ammonium to ammonium. The
flux of ammonia across the membrane is then determined by
the relative concentrations of ammonia in the feed to that
of the draw solution, which has very little ammonia. This
approach can be used to remove ammonia from a complex urine
feed and concentrate it into a binary solution which will
enable nitrogen production thought a downstream ammonia
fuel cell
Numerical simulations of the diffusional growth rate pattern on graupel and implications for graupel electrification
No full textThe Relative Diffusional Growth Rate (RDGR) theory states that the ice particle growing faster from vapor diffusion at the point of collision obtains the positive charge. The application of this theory in modeling studies has assumed the ice particle grows at a specific rate uniformly across the surface, but laboratory studies agree that accretion affects the ice surface unevenly, consequently impacting the charge transfer. Our goal is to numerically model the diffusional growth rate of a graupel particle at a refined spatial scale to understand how the growth pattern varies depending on ventilation and droplet accretion in an idealized setting. We perform Computational Fluid Dynamic (CFD) simulations of the flow around graupel to estimate droplet collision probabilities along the surface. Then, we conduct simulations of the vapor transport in the domain from the flow solution with and without droplets modifying the original graupel shape. These results are used to calculate the total radius diffusional growth rate from the perspective of the graupel surface. For the far field, the ventilation enhances the diffusional growth in the particle’s lower hemisphere. For the local field, the flow advects a fraction of the vapor released by freezing droplets to the environment, reducing its use in graupel's diffusional growth. This decrease is dependent on the droplet size and flow speed. In conditions of positive charging by the RDGR theory, the area prone to positive charging is more extensive with greater variability for a drop size distribution (DSD) of larger droplets than smaller ones, but requires a greater rime accretion mass. We found differences between ventilated and stationary solutions, by varying the DSD and whether using a constant or variable droplet collision rate. The overlapping of the droplets on the graupel surface revealed competing effects in expanding regions prone to positive charging or locally intensifying the growth rate
Box 1, Folder 6, MGN Transcripts Meditaciones Ligeras I
No full textThe Boyd Carter Papers represent a significant archival collection housed in the Hispanic Studies Collection in Texas Tech University's CMLL building. Dr. Boyd Carter was a distinguished scholar of Latin American literature who was active from the 1940s to his death in 1980. He held professorships at the University of Nebraska, Southern Illinois University, and the University of Missouri before concluding his career at Texas Tech University (1978-1980). Upon joining TTU, Carter donated his extensive archive to the university, including rare books, microfilm collections, bibliographical notes, and periodicals focusing on Latin American literature from 1850-1950, with particular emphasis on the famed Mexican writer Manuel Gutiérrez Nájera
A New and Simple Thermal Model of the Lunar Surface, for Early Phase System Design Studies
No full textPhilipp B. Hager, European Space Agency (ESA), NetherlandsMatthew T. Vaughan, European Space Agency (ESA), NetherlandsICES102: Thermal Control for Planetary and Small Body
Surface MissionsThe 54th International Conference on Environmental Systems was held in Prague, Czechia, on 13 July 2025 through 17 July 2025.Early design phases for lunar surface assets such as
instruments, rovers, habitats, or landers require reliable
predictions of the thermal environment on the Moon.
Elaborate, numerical models exist, are correlated against
measurements and predict temperatures with a high
precision. Yet, modelling the lunar surface appropriately
with detailed models, considering temperature dependencies
of material properties, mineralogical differences, angle
dependence of thermo-optical properties, or accounting for
topography, is computationally expensive. Furthermore,
these detailed and elaborate thermal models are at odds
with the fidelity of the spacecraft design in early design
phases. In consequence, there is a need for quick but
accurate assessments of the lunar thermal environment at
system level at early design stages. Apart from the
numerical models there are also numerous analytical heat
balance based models for lunar surface temperature
predictions in literature. They allow reproducing daytime
temperatures but are often inaccurate or not applicable for
eclipses. In this paper we compare several existing
analytical models with each other and with an
implementation of a widely accepted numerical model. The
simplified model’s shortcomings are highlighted and a
refined analytical model, called ESAMT, is presented that
allows a higher accuracy throughout lunar day and eclipses
Behaviorism, Constructivism, and Humanism in Viola Performance and Pedagogy: An Examination of Learning Theories for Music Teachers and Students
No full textThe study of music teaching and music performance are often seen as two different worlds, and they are. However, performance majors in viola are frequently given opportunities to teach in applied settings and face a lack of essential pedagogical understanding when providing instruction for their music students. This paper examines three learning theories, Behaviorism, Constructivism, and Humanism, to address this issue faced by some string pedagogues and to positively affect students’ performance experiences with educational goals in mind. This research includes social analysis, historiography, and performance practice as methodologies. Learning theories can potentially develop 'competence-based learning’ in performance and pedagogy, promoting the growth of skills, knowledge, and positive attitudes. The transfer and application of content explored within this examination to other musical instruments is recommended.Related performance for this degree -- Ryellen de Souza's DMA Viola Recital 1: https://hdl.handle.net/2346/103891
Related performance for this degree -- Ryellen de Souza's DMA Viola Recital 2: https://hdl.handle.net/2346/103892
Related performance for this degree -- Ryellen de Souza's DMA Viola Recital 3: https://hdl.handle.net/2346/103893
Related performance for this degree -- Ryellen de Souza's DMA Viola Recital 4: https://hdl.handle.net/2346/10389