Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Population & Data envelopment analysis. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Origin of Electrochemical, Structural, and Transport Properties in Nonaqueous Zinc Electrolytes

Abstract: Through coupled experimental analysis and computational techniques, we uncover the origin of anodic stability for a range of nonaqueous zinc electrolytes. By examination of electrochemical, structural, and transport properties of nonaqueous zinc electrolytes with varying concentrations, it is demonstrated that the acetonitrile-Zn(TFSI)2, acetonitrile-Zn(CF3SO3)2, and propylene carbonate-Zn(TFSI)2 electrolytes can not only support highly reversible Zn deposition behavior on a Zn metal anode (≥99% of Coulombic efficiency) but also provide high anodic stability (up to ∼3.8 V vs Zn/Zn(2+)). The predicted anodic stability from DFT calculations is well in accordance with experimental results, and elucidates that the solvents play an important role in anodic stability of most electrolytes. Molecular dynamics (MD) simulations were used to understand the solvation structure (e.g., ion solvation and ionic association) and its effect on dynamics and transport properties (e.g., diffusion coefficient and ionic conductivity) of the electrolytes. The combination of these techniques provides unprecedented insight into the origin of the electrochemical, structural, and transport properties in nonaqueous zinc electrolytes.

Theory of gas diffusion and permeation in inorganic molecular-sieve membranes

Abstract: Theoretical models of gas diffusion and permeation in microporous molecular-sieve membranes are presented. The effect of the adsorbed diffusant on the total transmembrane flow is insignificant for permanent gases. For highly adsorbable gases the effect of the adsorbed molecules on the total transmembrane flux may be high at low temperatures. The activation energy of diffusion increases when the kinetic diameter of the diffusant increases. The activation energy of gas diffusion compares well with the values calculated based on the Lennard-Jones potential. Maximum possible permeability coefficients calculated for He in the molecular-sieve membranes do not exceed [approximately] 30,000 Barrer at room temperature. The experimentally observed value for He permeability is [approximately] 1,000 Barrer (T = 30 C) because of the high tortuosity ([tau] [approx] 25) and low porosity ([theta] = 0.22) of the membrane porous structure.

Application of Wavelet Approach for ASCE Structural Health Monitoring Benchmark Studies

Abstract: This paper presents an application of wavelet analysis for damage detection and locating damage region(s) for the ASCE structural health monitoring benchmark data The response simulation data were generated basically by a FEM program provided by the ASCE Task Group on Health Monitoring for a four-story prototype building structure subjected to simulated stochastic wind loading Damage was introduced in the middle of response by breaking one or more structure elements such as interstory braces Wavelets were used to analyze the simulation data It was found that structural damage due to sudden breakage of structural elements and the time when it occurred can be clearly detected by spikes in the wavelet details The damaged region can be determined by the spatial distribution pattern of the observed spikes The effects of measurement noise and the severity of damage were investigated The results in this paper illustrate a great promise of wavelet analysis for structural health monitoring, especially for an on-line application