The impact of transportation network companies on urban transportation systems

This study uses a mixed-methods approach to investigate how Transportation Network Companies (TNCs) are impacting urban transportation systems. First, using survey and National Household Travel Survey data this study seeks to understand if TNCs are inducing travel demand. Second, using survey data this study analyzes what people value in regards to TNCs. Overall this study found that most people are using TNCs for occasional, weekend travel. For some portion of users TNCs may be inducing travel demand. This study also finds that most users value the convenience of TNCs. These findings imply that TNCs are not transforming urban transportation but are acting as supplemental transportation servicesCommunity and Regional Plannin

Charging-driven coarsening and melting of a colloidal nanoparticle monolayer at an ionic liquid-vacuum interface

We induce and investigate the coarsening and melting dynamics of an initially static nanoparticle colloidal monolayer at an ionic liquid-vacuum interface, driven by a focused, scanning electron beam. Coarsening occurs through grain interface migration and larger-scale motions such as grain rotations, often facilitated by sliding dislocations. The progressive decrease in area fraction that drives melting of the monolayer is explained using an electrowetting model whereby particles at the interface are solvated once their accumulating charge recruits sufficient counterions to subsume the particle. Subject to stochastic particle removal from the monolayer, melting is recapitulated in simulations with a Lennard-Jones potential. This new driving mechanism for colloidal systems, whose dynamical timescales we show can be controlled with the accelerating voltage, opens the possibility to manipulate particle interactions dynamically without need to vary particle intrinsic properties or surface treatments. Furthermore, the decrease in particle size availed by electron imaging presents opportunities to observe force and time scales in a lesser-explored regime intermediate between typical colloidal and molecular systems.Comment: 14 pages, 6 figures, also see supplementary ancilliary fil

Probing Structural Transitions in the Intrinsically Disordered C-Terminal Domain of the Measles Virus Nucleoprotein by Vibrational Spectroscopy of Cyanylated Cysteines

A proof-of-concept demonstration that our methodology (infrared spectroscopy and cyanylated cysteine) is useful for monitoring structural transitions in unstructure proteins. --author-supplied descriptio

Деградація структури і пошкодження сіткою тріщин сталі металургійного обладнання

Розроблено автоматизований метод кількісного аналізу сітки тріщин для діагносту- вання стану роликів машин безперервного лиття заготовок. Запропоновано струк- турну методологію ідентифікації тріщин. Показано ефективність методології вияв- лення тріщин на основі програмного оброблення цифрових зображень. Порівняно параметри сітки тріщин на окисненій поверхні зразків ролика після зішліфовування зовнішнього шару

Why accumulation mode organic electrochemical transistors turn off much faster than they turn on

Understanding the factors underpinning device switching times is crucial for the implementation of organic electrochemical transistors (OECTs) in neuromorphic computing and real-time sensing applications. Existing models of device operation cannot explain the experimental observations that turn-off times are generally much faster than turn-on times in accumulation mode OECTs. Through operando optical microscopy, we image the local doping level of the transistor channel and show that device turn-on occurs in two stages, while turn-off occurs in one stage. We attribute the faster turn-off to a combination of engineering as well as physical and chemical factors including channel geometry, differences in doping and dedoping kinetics, and the physical phenomena of carrier density-dependent mobility. We show that ion transport is limiting the device operation speed in our model devices. Our study provides insights into the kinetics of OECTs and guidelines for engineering faster OECTs