Rising temperatures driven by climate change and development patterns affect travel behavior, including public transit use and active transport; however, most studies rely on ambient temperature measures and assume uniform behavioral responses. In this study, we investigated how individuals’ perceived heat thresholds are associated with transit use and moderate-to-vigorous physical activity (MVPA), among adults in a humid subtropical climate. We used data from a 2022 cross-sectional survey of adults in Austin, Texas (n = 1,087). Respondents self-reported their perceived heat threshold (i.e., the temperature at which they would not go on a walk outside), weekly frequency of using public transit, and MVPA levels via the International Physical Activity Questionnaire–Short Form. We used ordinal logistic regression to assess the association between perceived heat threshold and transit use (0, 1–2, ≥3 days), multinomial logistic regression to examine the association within transit use categories (0, 1–2, 3–4, ≥5 days), and multivariable linear regression to assess the association with MVPA. Individuals who reported higher perceived heat thresholds had higher odds of using public transit. This association was primarily driven by the transition from non-use to occasional transit use (1–2 days/week), with no evidence that perceived heat thresholds were associated with more frequent transit use. In contrast, perceived heat threshold was not significantly associated with MVPA. Our findings suggest that individual heat-related behavioral thresholds may help explain individual mobility decisions, but not overall physical activity levels.
The electrochemical reduction of CO2 into CO has emerged as a strategically significant technology for mitigating the environmental impacts stemming from anthropogenic global warming while enabling the conversion of CO2 into energy resources. Syngas, a critical feedstock in the petroleum industry for synthesizing fuels and chemicals, is traditionally produced via coal gasification and natural gas reforming. However, against the backdrop of the gradual exhaustion of fossil energy reserves and escalating environmental exigencies, electrochemical CO2 reduction (CO2RR) coupled with water splitting has emerged as an ideal alternative route to produce syngas with tunable CO/H2 ratios. Zn, a crustally abundant element in the Earth’s crust, emerges as a viable and cost-effective substitute for noble metal-based electrocatalysts (e.g., Au, Ag) in CO2RR. The development of cost-competitive, highly catalytically active electrocatalysts are critical prerequisites for mitigating atmospheric CO2 accumulation and enhancing the valorization of CO2RR products. Herein, through the morphology regulation of an electrodeposited Zn–based catalyst followed by solution–phase reconstruction and thermal treatment, a nanowire–structured Zn catalyst was fabricated. The catalyst exhibits remarkable performance for CO2RR, demonstrating an ultra–wide tunable CO/H2 ratio from 1.4 to 5.8 at potentials between − 0.6 and − 1.4 V vs. reversible hydrogen electrode (RHE). At − 1.2 V vs. RHE, a stable CO/H2 ratio of 3 was maintained continuously for 9 h. Furthermore, the influences of the KHCO3 electrolyte concentration on the catalytic performance of the Zn–24 h/H2 catalyst was investigated. The result demonstrate that higher KHCO3 electrolyte concentrations can enhance the current density but the hydrogen evolution will be promoted, thus reduce CO selectivity. This phenomenon can be explained by the enhanced electrolyte conductivity and the increased local pH near the cathode surface, which favors the hydrogen evolution reaction over CO2 reduction and narrow the tunable range of the CO/H2 ratio. By tailoring catalyst morphology and electrolyte concentration, the syngas composition can be effectively modulated. This study offers new possibility for designing advanced catalytic system suitable for a variety of syngas–based industrial applications.
Hybrid electromagnetic transient (EMT)/three-phase phasor (RMS) domain co-simulation can be a practical alternative to full EMT studies for converter-interfaced grids. However, its efficacy primarily depends on the selection of interface/boundary parameters. While prior works focus on improving the efficacy of co-simulation for transmission grids, this paper investigates the accuracy of co-simulation in comparison with EMT analysis for a converter-rich, transmission-distribution grid in DIgSILENT PowerFactory. Using a modified IEEE 9-Bus system, this paper examines the impacts of boundary configuration and the region of fault modeling on the accuracy of co-simulation responses. The results demonstrate that transformers adjacent to the interface element and the region of fault representation can influence co-simulation responses. This study also recommends potential ranges of boundary region and co-simulation transformation settings for obtaining reliably accurate results under different conditions.
NASA's Curiosity rover is exploring a 5 km tall sedimentary mound that is hypothesized to record the transition from a warm and wet (phyllosilicate-rich) to a cold and drier (sulfate-rich) Mars. Evidence of magnesium sulfate-bearing rock has shown that Curiosity has crossed through this phyllosilicate-sulfate transition. Recently, Curiosity arrived at the Amapari Marker Band, a darker, indurated unit that can be traced laterally for tens of kilometers in orbiter images. Here, Curiosity found evidence for a very broad lake, and bedforms interpreted as wave-ripple laminated sedimentary rock that likely was deposited in shallow water in the explored location, before becoming a deeper lake. These rocks are enriched in Fe, Mn, and Zn which has major implications for groundwater paleohydrology in Gale crater. Three formation hypotheses are considered: concretion formation during early diagenetic alteration of shallow lake sediments, laterization or leaching of the sediments, and addition of Fe, Mn, and Zn by a mildly acidic and reducing groundwater interacting with a redox and/or pH front in a stratified lake. The preferred interpretation of the metal enrichments within the Amapari Marker band sedimentary rocks is that they formed in a shallow water environment at a redox and/or pH front within the ripple unit, which drove precipitation and concentration of metals. If the enrichments are due to groundwater alteration, these processes could link subsurface and surface environments. Water and the presence of high amounts of redox sensitive elements and other metals are favorable indicators for habitability.
