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The main objective of this study is to provide a brief summary of recent torsional-flexural tests conducted on a lipped channel section featuring multiple intermediate longitudinal stiffeners in the web and flanges, as well as return lips. The specimens were cold-formed from high-strength low- alloy steel with a nominal yield strength of 690 MPa (100 ksi). These torsional-flexural tests extend previously conducted pure compression and flexural tests on the same section and are intended to assess the adequacy of current design strength prediction equations for cold-formed steel members fabricated from high-strength steels under different loading conditions. Two experimental test configurations were explored: (1) a 3-point bending setup with warping restrained supports, and (2) a 4-point bending setup with warping unrestrained supports. The advantages and limitations of each configuration are discussed. Overall, the second configuration provides a more straightforward approach for conducting torsional-flexural tests on cold-formed steel sections and is better suited for computational modeling due to boundary conditions that more closely approximate idealized behavior. A brief discussion of the preliminary experimental and numerical results is provided. These results will be used to evaluate the adequacy of the design strength prediction equations provided in the AISI S100-2024 Specification. 

Abstract The Quasi‐Biennial Oscillation (QBO) is a dominant mode of stratospheric variability and is known to modulate the variability of the ionosphere‐thermosphere (IT) system. However, the extent of its influence on the ionosphere‐thermosphere system remains uncertain due to weak signals and confounding with similar periodicities in solar flux. In this study, we investigated QBO signatures in ionosonde derived peak electron density (NmF2), GNSS total electron content (TEC), and thermospheric composition (O/N₂) from the Global Ultraviolet Imager on NASA's Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite. Local empirical models are used to isolate the stratospheric QBO signature in NmF2 and TEC. Multi‐channel singular spectrum analysis is used to reveal seasonal modulation of theO/N₂response to QBO. We found that the amplitude of non‐solar origin QBO in NmF2, TEC, andO/N₂reaches up to 4% and exhibits an out‐of‐phase relation with stratospheric QBO phase at 30 hPa (QBO30). The TEC QBO signal shows strong regional variability, peaking over Europe. TheO/N₂QBO signal shows clear seasonality with maximum correlation with QBO30 around the equinoxes. The NmF2 response to stratospheric QBO is enhanced at most stations during the September equinox. The QBO signal inO/N₂at different latitudes shows maximum correlation with the stratospheric QBO at different pressure levels. Overall, the global reduction in NmF2, TEC, andO/N₂during the eastward QBO phase, along with their seasonal structure, is consistent with enhanced mixing driven by migrating diurnal tide. However, the regional structure in the TEC response implies additional mechanisms with varying spatial influence and vertical extent. 

Abstract Long‐term ionospheric trends have been widely studied, but their origin and magnitude remain subjects of debate. This study quantifies the linear trend in the F2‐region critical frequency (foF2) and its local time dependence using observations from eight low‐latitude ionosonde stations. The trend is derived by fitting and removing background variations using a local empirical model of foF2 that uses known drivers. The resulting trends are largely negative, reaching a maximum magnitude of about −0.09 MHz/yr at the Cachoeira Paulista (22.70°S, 45.00°W) station around midnight. Only two of the eight stations examined exhibit positive trends, with the largest positive value observed over Fortaleza (3.90°S, 38.40°W), reaching +0.04 MHz/yr at 14 local time. We further estimate the “geometrical trend” of foF2 at these ionosonde stations by assuming that the URSI foF2 climatology remains constant in quasi‐dipole coordinates under secular variation of the Earth's magnetic field. Here, “geometrical trend” refers to the apparent foF2 trend component arising solely from displacement between magnetic and geographic coordinates. Our results indicate that the geometrical trend largely accounts for the observed daytime trend at five out of eight ionosondes. The largest discrepancy between the observed and geometrical trends occurs at nighttime in the eastern Brazilian sector, where the strongly negative observed trends are qualitatively consistent with estimated changes in vertical plasma transport induced by horizontal thermospheric winds. Discrepancies are also found at all local times for stations located near the geomagnetic equator, where the main magnetic field strength is decreasing and potentially affecting the E × B drift. 

The core component of this study was a five-week summer camp that provided Arduino and robotics workshops and group activities to girls in grades 6-11. All activities were structured to ensure that learning took place in a constructivist environment. The camp was designed as a program to increase girls’, especially minorities’ participation in computer science and engineering. Key elements of camp participants’ STEM interest, self-efficacy, and contextual factors were measured both before and after the camp. With the collection and analyses of the survey data, our present study is to examine how constructivist learning environment may impact adolescent girls’ STEM learning and interests. 

The purpose of the study is to explore and theorize the constructivist learning environment for secondary female students’ STEM learning. The study was built on a funded program featured a tiered-team structure, hands-on experience, and interactive mentorship for engaging female students from Grades 6-11 in a five-week Summer Camp to learn Arduino programming & Robotics Design and integration of these tools to conduct projects in ubiquitous intelligent systems. In conducting this study, we used the case study method to provide a more multifaceted perspective on the camp, and how these perspectives inform an understanding of how the project’s features impacted the students. All 37 female students participated in the survey, and eight participated in the interviews. The findings indicate that students were able to heighten their self-confidence and motivation. The themes of the learning environment were identified: knowledge enhancement, STEAM experience, as well as support and encouragement. The program had significant impacts on students’ identity related to STEM identity, motivation and interest, and self-confidence. It also significantly impacts their sense of belonging, including peers' and mentors' sense of belonging. The study provided research evidence for designing STEM learning projects to enhance female STEM learning. 

X-ray spectroscopy has long been a powerful diagnostic tool for hot, dilute plasmas, providing insights into plasma conditions by measuring line shifts and broadenings of atomic transitions. The technique critically depends on the accuracy of atomic physics models used to interpret spectroscopic measurements for inferring plasma properties such as free-electron density and temperature. Over the past decades, the atomic and plasma physics communities have developed robust atomic physics models to account for various processes in hot, dilute classical plasmas. While these models have been successful in that regime, their applicability becomes uncertain when interpreting x-ray spectroscopy experiments of above-solid-density plasmas. Given that finite-temperature density-functional theory (DFT) offers a more accurate description of dense plasma environments, we present the development of a DFT-based multi-band kinetic model, VERITAS, designed to improve the interpretation of x-ray spectroscopic measurements in high-density plasmas produced by laser-driven spherical implosions. This work details the VERITAS model and its application to both time-integrated and time-resolved x-ray spectra from implosion experiments on OMEGA. The advantages and limitations of the VERITAS model will also be discussed, along with potential directions for advancing x-ray spectroscopy of dense and superdense plasmas.