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Maiorana A.,Rensselaer Polytechnic Institute | Spinella S.,Rensselaer Polytechnic Institute | Spinella S.,Six Metrotech Center | Gross R.A.,Rensselaer Polytechnic Institute

A series of biobased epoxy monomers were prepared from diphenolic acid (DPA) by transforming the free acid into n-alkyl esters and the phenolic hydroxyl groups into diglycidyl ethers. NMR experiments confirmed that the diglycidyl ethers of diphenolates (DGEDP) with methyl and ethyl esters have 6 and 3 mol % of glycidyl ester. Increasing the chain length of DGEDP n-alkyl esters from methyl to n-pentyl resulted in large decreases in epoxy resin viscosity (700-to-11 Pa·s). Storage modulus of DPA epoxy resins, cured with isophorone diamine, also varied with n-alkyl ester chain length (e.g., 3300 and 2100 MPa for the methyl and n-pentyl esters). The alpha transition temperature of the cured materials showed a linear decrease from 158 to 86°C as the ester length increases. The Young's modulus and tensile strengths were about 1150 and 40 MPa, respectively, for all the cured resins tested (including DGEBA) and varied little as a function of ester length. Degree of cure for the different epoxy resins, determined by FTIR and DSC, closely approached the theoretical maximum. The result of this work demonstrates that diglycidyl ethers of n-alkyl diphenolates represent a new family of biobased liquid epoxy resins that, when cured, have similar properties to those from DGEBA. (Graph Presented). © 2015 American Chemical Society. Source

Grieco L.A.,Polytechnic of Bari | Rizzo A.,Polytechnic of Bari | Rizzo A.,Six Metrotech Center | Colucci S.,Polytechnic of Bari | And 4 more authors.
Computer Communications

The ongoing revolution of Internet of Things (IoT), together with the growing diffusion of robots in many activities of every day life, makes IoT-aided robotics applications a tangible reality of our upcoming future. Accordingly, new advanced services, based on the interplay between robots and "things", are being conceived in assisting humans. Nevertheless, the path to a mature development of IoT-aided robotics applications requires several pivotal issues to be solved, design methodologies to be consolidated, and strong architectural choices to be discussed. This paper discusses technological implications, open issues, and target applications in the IoT-aided robotics domain. In particular, the present contribution is four-folded. First, it provides a solid state of the art on the main topics related to IoT-aided robotics services: communication networks, robotics applications in distributed and pervasive environments, semantic-oriented approaches to consensus, and network security. Second, it highlights the most important research challenges to be faced. Third, it describes the technological tools available nowadays. Fourth, it summarizes lessons learned to foster a joint scientific investigation among research teams with complementary skills. © 2014 Elsevier B.V. Source

Jazebi S.,Six Metrotech Center | Hadji M.M.,University of Alberta | Naghizadeh R.A.,Hamedan University of Technology
IEEE Transactions on Smart Grid

This paper deals with reconfiguration of distribution system to minimize power losses, deviation of nodes voltages and branches current constraint violations. This means alternation of feeders' topological structure by changing the status of tie and sectionalizing switches. The work presented here is a step forward to define the reconfiguration problem closer to reality by considering the effect of harmonic loads. To solve this complicated combinatorial, non-differentiable constrained optimization problem, novel heuristic optimization techniques such as Shuffled Frog Leaping Algorithm (SFLA) and Imperialist Competitive Algorithm (ICA) are employed. The methods are compared with Discrete Particle Swarm Optimization (DPSO) algorithm to examine their performance including computational time, convergence rate, and accuracy of results. In this context, experiments are conducted on 69-bus and 84-bus distribution test systems for the short- and long-term reconfiguration scenarios. The obtained results establish that harmonic losses are a major deciding factor in reconfiguration and harmonic loads cannot be represented with only fundamental components. © 2014 IEEE. Source

Baamer M.,New York University | Suescun-Florez E.,New York University | Machairas N.,New York University | Iskander M.,Six Metrotech Center
Geotechnical Special Publication

An experimental program was conducted to quantify the strain rate dependency of silica sand under different low to intermediate strain rates. Measurements of axial stress, axial strain and stiffness were explored to assess the sensitivity of mechanical properties to strain rate. Strain rates were applied on samples subjected to uniaxial compression stresses within a range of 0.01 to 100 %/s. The tests help facilitate the incorporation of strain rate dependency of soil response in geotechnical modeling of soil-structure interaction problems. Available observations of the response of sand under monotonic loading suggest that sand may exhibit significant strain rate dependency. © ASCE 2015. Source

Guzman I.L.,New Jersey Institute of Technology | Iskander M.,Six Metrotech Center | Bless S.,New York University
Mechanics Research Communications

In this study, a transparent sand surrogate was employed along with high-speed imagery to un-intrusively visualize the penetration of a spherical projectile into the center of a saturated granular target, representing angular sand, at speeds ranging between 60 and 150 m/s. The transparent sand was made by saturating an angular granular fused quartz waste product with a matched refractive index pore fluid made of sucrose. A distinct zone of opacity was observed traveling ahead of the projectile. The opacity zone appears circular during initial penetration and transitions into the shape of an elongated cone in shots with higher initial velocities. Some healing was also observed with time and some increase in transparency was observed. Some of the opacity is attributed to dilatancy of the granular fused quartz during penetration, and healing is attributed to flow of pore fluid into the dilated zone. © 2015 Elsevier Ltd. Source

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