305 research outputs found
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Compositional Evolution of Secondary Organic Aerosol as Temperature and Relative Humidity Cycle in Atmospherically Relevant Ranges
Two Factor Authentication Made Easy
Authentication on the Web is a challenge that can have a negative effect on user experience if it becomes overly complicated and cumbersome. This experience is even more crucial for older and visually impaired users due to their functional abilities. Web applications typically authenticate users by requesting for information that only the user knows (e.g. password). To enhance security, two-factor authentication (2FA) are increasingly implemented, which require the user to manually transfer information between 2FA devices and the Web application. This process can impose usability barriers and stress on human’s memory. This paper proposes a technique to mitigate such issues by using wearables as the 2FA device, and to allow authentication information to be transferred seamlessly and automatically from the device to the Web application. From our preliminary results, older users found our approach less stressful on the human’s memory and easier to use
Language-guided Active Sensing of Confined, Cluttered Environments via Object Rearrangement Planning
Language-guided active sensing is a robotics subtask where a robot with an
onboard sensor interacts efficiently with the environment via object
manipulation to maximize perceptual information, following given language
instructions. These tasks appear in various practical robotics applications,
such as household service, search and rescue, and environment monitoring.
Despite many applications, the existing works do not account for language
instructions and have mainly focused on surface sensing, i.e., perceiving the
environment from the outside without rearranging it for dense sensing.
Therefore, in this paper, we introduce the first language-guided active sensing
approach that allows users to observe specific parts of the environment via
object manipulation. Our method spatially associates the environment with
language instructions, determines the best camera viewpoints for perception,
and then iteratively selects and relocates the best view-blocking objects to
provide the dense perception of the region of interest. We evaluate our method
against different baseline algorithms in simulation and also demonstrate it in
real-world confined cabinet-like settings with multiple unknown objects. Our
results show that the proposed method exhibits better performance across
different metrics and successfully generalizes to real-world complex scenarios.Comment: Accepted in IEEE/RAS ICRA'2
Complementarity of lacustrine pollen and sedimentary DNA in representing vegetation on the central-eastern Tibetan Plateau
Plant environmental DNA extracted from lacustrine sediments (sedimentary DNA, sedDNA) has been increasingly used to investigate past vegetation changes and human impacts at a high taxonomic resolution. However, the representation of vegetation communities surrounding the lake is still unclear. In this study, we compared plant sedDNA metabarcoding and pollen assemblages from 27 lake surface-sediment samples collected from alpine meadow on the central-eastern Tibetan Plateau to investigate the representation of sedDNA data. In general, the identified components of sedDNA are consistent with the counted pollen taxa and local plant communities. Relative to pollen identification, sedDNA data have higher taxonomic resolution, thus providing a potential approach for reconstructing past plant diversity. The sedDNA signal is strongly influenced by local plants while rarely affected by exogenous plants. Because of the overrepresentation of local plants and PCR bias, the abundance of sedDNA sequence types is very variable among sites, and should be treated with caution when investigating past vegetation cover and climate based on sedDNA data. Our finding suggests that sedDNA analysis can be a complementary approach for investigating the presence/absence of past plants and history of human land-use with higher taxonomic resolution
Optimization of a continuous flow electrocoagulation as pretreatment for membrane distillation of the waste stream in vinyl ester resin production
Vinyl ester resin production wastewater (VERW) contains high concentrations of organics particularly, methacrylic acid and bisphenol A, which are hazardous chemicals and harmful to the aquatic environment. Therefore, there is an urgent need to properly treat the effluent before discharge into the aquatic system. In this work, direct contact membrane distillation (DCMD) was explored as an advanced treatment of the VERW pre-treated by a continuous flow electrocoagulation (EC) and peroxi-electrocoagulation (PEC) processes. Optimization of EC and PEC processes were investigated and the DCMD performance was evaluated. Results showed that the optimal value of current density and polyacrylamide (PAM) dosage was 15 mA/cm2 and 1 mg/L, respectively in the EC process. For the PEC process, the optimal addition of hydrogen peroxide (H2O2) dosage was four times of the chemical oxygen demand (COD) concentration of EC effluent. The COD of VERW was effectively removed via EC followed by PEC (EC-PEC), resulting in the significant alleviation of membrane fouling during DCMD filtration of VERW. The initial flux of DCMD filtration of VERW pre-treated via EC-PEC improved by 35%, compared that only pre-treated by EC. Moreover, the concentration factor (CF) of the DCMD system reached up to 8.1 and the conductivity of distillate was less than 33.2 μS/cm. Hence, the EC and membrane distillation hybrid process paves a new way for the effective treatment of waste steam from resin production.</p
Cross‐Scale Decoupling Kinetic Processes in Lithium‐Ion Batteries Using the Multi‐Dimensional Distribution of Relaxation Time
To non‐destructively resolve and diagnose the degradation mechanisms of lithium‐ion batteries (LIBs), it is necessary to cross‐scale decouple complex kinetic processes through the distribution of relaxation times (DRT). However, LIBs with low interfacial impedance render DRT unreliable without data processing and closed‐loop validation. This study proposes a hierarchical analytical framework to enhance timescale resolution and reduce uncertainty, including interfacial impedance reconstruction and multi‐dimensional DRT analysis. Interfacial impedance is reconstructed by eliminating simulated inductive and diffusive impedance based on a high‐fidelity frequency‐domain model. Multi‐dimensional DRT decouples solid electrolyte interphase (SEI) and charge transfer (CT) processes by the reversibility of electrochemical reactions with state of charge (SOC) to characterize electrode kinetic evolution driven by SOC and temperature through timescales and peak area. The findings reveal that reconstructed impedance improves the accuracy of identified time constants by ≈20%. Cross‐scale DRT results reveal that SOCs below 10% at 25 °C effectively distinguish electrode kinetics due to the high correlation between cathodic CT and SOC. Kinetic metrics characterize that anodic SEI or CT are different control steps limiting the low‐temperature performance of different cells. This work underscores the potential of the proposed framework for non‐destructive diagnostics of kinetic evolution
Optimization of a continuous flow electrocoagulation as pretreatment for membrane distillation of the waste stream in vinyl ester resin production
Vinyl ester resin production wastewater (VERW) contains high concentrations of organics particularly, methacrylic acid and bisphenol A, which are hazardous chemicals and harmful to the aquatic environment. Therefore, there is an urgent need to properly treat the effluent before discharge into the aquatic system. In this work, direct contact membrane distillation (DCMD) was explored as an advanced treatment of the VERW pre-treated by a continuous flow electrocoagulation (EC) and peroxi-electrocoagulation (PEC) processes. Optimization of EC and PEC processes were investigated and the DCMD performance was evaluated. Results showed that the optimal value of current density and polyacrylamide (PAM) dosage was 15 mA/cm2 and 1 mg/L, respectively in the EC process. For the PEC process, the optimal addition of hydrogen peroxide (H2O2) dosage was four times of the chemical oxygen demand (COD) concentration of EC effluent. The COD of VERW was effectively removed via EC followed by PEC (EC-PEC), resulting in the significant alleviation of membrane fouling during DCMD filtration of VERW. The initial flux of DCMD filtration of VERW pre-treated via EC-PEC improved by 35%, compared that only pre-treated by EC. Moreover, the concentration factor (CF) of the DCMD system reached up to 8.1 and the conductivity of distillate was less than 33.2 μS/cm. Hence, the EC and membrane distillation hybrid process paves a new way for the effective treatment of waste steam from resin production.</p
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