More Like this

1. Weighted Mobility

   https://doi.org/10.1002/adma.202001537  

   Snyder, G_Jeffrey; Snyder, Alemayouh_H; Wood, Maxwell; Gurunathan, Ramya; Snyder, Berhanu_H; Niu, Changning (May 2020, Advanced Materials)

   Abstract Engineering semiconductor devices requires an understanding of charge carrier mobility. Typically, mobilities are estimated using Hall effect and electrical resistivity meausrements, which are are routinely performed at room temperature and below, in materials with mobilities greater than 1 cm²V^‐1s^‐1. With the availability of combined Seebeck coefficient and electrical resistivity measurement systems, it is now easy to measure the weighted mobility (electron mobility weighted by the density of electronic states). A simple method to calculate the weighted mobility from Seebeck coefficient and electrical resistivity measurements is introduced, which gives good results at room temperature and above, and for mobilities as low as 10⁻³cm²V^‐1s^‐1,Here, μ_wis the weighted mobility, ρ is the electrical resistivity measured in mΩ cm,Tis the absolute temperature in K,Sis the Seebeck coefficient, andk_B/e = 86.3 µV K^–1. Weighted mobility analysis can elucidate the electronic structure and scattering mechanisms in materials and is particularly helpful in understanding and optimizing thermoelectric systems. 

   more » « less
2. Autonomous in situ measurements of freshwater alkalinity

   https://doi.org/10.1002/lom3.10404  

   Shangguan, Qipei; Lai, Chun‐Ze; Beatty, Cory M.; Young, Fischer L.; Spaulding, Reggie S.; DeGrandpre, Michael D. (December 2020, Limnology and Oceanography: Methods)

   Abstract Total alkalinity (A_T) is an important parameter in the study of aquatic biogeochemical cycles, chemical speciation modeling, and many other important fundamental and anthropogenic (e.g., industrial) processes. We know little about its short‐term variability, however, because studies are based on traditional bottle sampling typically with coarse temporal resolution. In this work, an autonomous A_Tsensor, named the Submersible Autonomous Moored Instrument for Alkalinity (SAMI‐alk), was tested for freshwater applications. A comprehensive evaluation was conducted in the laboratory using freshwater standards. The results demonstrated excellent precision and accuracy (± 0.1%–0.4%) over the A_Trange from 800 to 3000 μmol L⁻¹. The system had no drift over an 8 d test and also demonstrated limited sensitivity to variations in temperature and ionic strength. Three SAMI‐alks were deployed for 23 d in the Clark Fork River, Montana, with a suite of other sensors. Compared to discrete samples, in situ accuracy for the three instruments were within 10–20 μmol L⁻¹(0.3–0.6%), indicating good performance considering the challenges of in situ measurements in a high sediment, high biofouling riverine environment with large and rapid changes in temperature. These data reveal the complex A_Tdynamics that are typically missed by coarse sampling. We observed A_Tdiel cycles as large as 60–80 μmol L⁻¹, as well as a rapid change caused by a runoff event. Significant errors in inorganic carbon system modeling result if these short‐term variations are not considered. This study demonstrates both the feasibility of the technology and importance of high‐resolution A_Tmeasurements. 

   more » « less
3. Brain-in-the-Loop Learning Using fNIR and Simulated Virtual Reality Surgical Tasks: Hemodynamic and Behavioral Effects.

   https://doi.org/10.1007/978-3-319-20816-9_31  

   Shewokis, P.A. (January 2015, Lecture Notes in Computer Science)

   Functional near infrared spectroscopy (fNIR) is a noninvasive, portable optical imaging tool to monitor changes in hemodynamic responses (i.e., oxygenated hemoglobin (HbO)) within the prefrontal cortex (PFC) in response to sensory, motor or cognitive activation. We used fNIR for monitoring PFC activation during learning of simulated laparoscopic surgical tasks throughout 4 days of training and testing. Blocked (BLK) and random (RND) practice orders were used to test the practice schedule effect on behavioral, hemodynamic responses and relative neural efficiency (EFFrel-neural) measures during transfer. Left and right PFC for both tasks showed significant differences with RND using less HbO than BLK. Cognitive workload showed RND exhibiting high EFFrel-neural across the PFC for the coordination task while the more difficult cholecystectomy task showed EFFrel-neural differences only in the left PFC. Use of brain activation, behavioral and EFFrel-neural measures can provide a more accurate depiction of the generalization or transfer of learning. 

   more » « less
4. Deployment of a Fixed-Wing Small Uncrewed Aircraft System for Urban Traffic–Related Air Pollution Assessment

   https://doi.org/10.1175/JTECH-D-24-0042.1  

   Silberstein, Jonathan; Sasse, Robert; Harjamaki, MiKyla; Rhodes, Michael; Cooper, Jenna; Downey, Ryan; Ritsch, Madison; Hannigan, Michael; Argrow, Brian (April 2025, Journal of Atmospheric and Oceanic Technology)

   Abstract Existing motor vehicle pollutant measurement techniques, including those that employ ground-based and multirotor small uncrewed aircraft system (sUAS) methods, can accurately measure traffic-related air pollution (TRAP) concentrations at a single location. However, these techniques often lack the mobility to assess pollutant trends across a large horizontal area. Fixed-wing sUAS represents an alternative instrument platform compared to ground-based systems and multirotor sUAS, as fixed-wing sUASs are able to carry air pollutant monitor payloads, have extended endurance, and offer expansive three-dimensional ranges across a field site. To demonstrate the utility of fixed-wing sUAS for urban TRAP assessment, we conducted two flights using a Super Robust Autonomous Aerial Vehicle–Endurant Nimble (RAAVEN) sUAS [University of Colorado (CU) Boulder] at a large field site adjacent to a major highway in Erie, Colorado. Concentrations of solid particulate matter (PM₁₀) and gas-phase (carbon monoxide) pollutants displayed decay as a function of altitude. During the morning flight, PM₁₀concentrations decreased from 19.0μg m⁻³at ground level to a minimum concentration of 14.3μg m⁻³at 90 m above ground level. During the afternoon flight, concentrations of PM₁₀displayed minimal vertical stratification, ranging from 8.9 at ground level to 10.0μg m⁻³at 45 m above ground level. Similarly, pollutants displayed decreasing concentrations as the horizontal distance from the roadway increased. Concentrations of TRAP may be significantly elevated in the area both above and beyond roadways, which contribute to additional pollutant exposure from on-road pollution sources. This study demonstrated that the general behavior of TRAP in near-road environments and that the use of fixed-wing sUAS are viable option for urban air quality measurements. Significance StatementThis study represents one of the first uses of a fixed-wing small uncrewed aircraft system (sUAS) to assess near-roadside concentrations of traffic-related air pollution (TRAP) in urbanized areas. We found that local meteorology, including local wind and solar radiation, had a substantial influence on the concentrations of common air pollutants, including particulate matter, black carbon, carbon monoxide, and carbon dioxide. Furthermore, we found large-scale spatiotemporal variation in pollutant concentrations as a function of the vertical and horizontal distance from the highway, indicating that diminished spatial variation employed in multirotor sUAS studies may not be sufficient to fully assess TRAP in roadside environments. 

   more » « less
5. Bottom quark energy loss and hadronization with B+ and $$ {\textrm{B}}_{\textrm{s}}^0 $$ nuclear modification factors using pp and PbPb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV

   https://doi.org/10.1007/JHEP02(2025)195  

   Hayrapetyan, A; Tumasyan, A; Adam, W; Andrejkovic, J W; Bergauer, T; Chatterjee, S; Damanakis, K; Dragicevic, M; Hussain, P S; Jeitler, M; et al (February 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> The production cross sections of$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$and B⁺mesons are reported in proton-proton (pp) collisions recorded by the CMS experiment at the CERN LHC with a center-of-mass energy of 5.02 TeV. The data sample corresponds to an integrated luminosity of 302 pb⁻¹. The cross sections are based on measurements of the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$→J/ψ(μ⁺μ⁻)ϕ(1020)(K⁺K⁻) and B⁺→J/ψ(μ⁺μ⁻)K⁺decay channels. Results are presented in the transverse momentum (p_T) range 7–50 GeV/cand the rapidity interval |y|<2.4 for the B mesons. The measuredp_T-differential cross sections of B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$in pp collisions are well described by fixed-order plus next-to-leading logarithm perturbative quantum chromodynamics calculations. Using previous PbPb collision measurements at the same nucleon-nucleon center-of-mass energy, the nuclear modification factors,R_AA, of the B mesons are determined. Forp_T>10 GeV/c, both mesons are found to be suppressed in PbPb collisions (withR_AAvalues significantly below unity), with less suppression observed for the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$mesons. In thisp_Trange, theR_AAvalues for the B⁺mesons are consistent with those for inclusive charged hadrons and D⁰mesons. Below 10 GeV/c, both B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$are found to be less suppressed than either inclusive charged hadrons or D⁰mesons, with the$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$R_AAvalue consistent with unity. TheR_AAvalues found for the B⁺and$$ {\textrm{B}}_{\textrm{s}}^0 $$ $B_s^0$are compared to theoretical calculations, providing constraints on the mechanism of bottom quark energy loss and hadronization in the quark-gluon plasma, the hot and dense matter created in ultrarelativistic heavy ion collisions. 

   more » « less