Time filter

Source Type

Palo Alto, CA, United States

PARC , formerly Xerox PARC, is a research and development company in Palo Alto, California, with a distinguished reputation for its contributions to information technology and hardware systems.Founded in 1970 as a division of Xerox Corporation, PARC has been responsible for such well known and important developments as laser printing, Ethernet, the modern personal computer, graphical user interface and desktop paradigm, object-oriented programming, ubiquitous computing, amorphous silicon applications, and advancing very-large-scale-integration for semiconductors.Xerox formed Palo Alto Research Center Incorporated as a wholly owned subsidiary in 2002. Wikipedia.

Reza Gholipour M.,University Laval | Dinh C.-T.,University Laval | Beland F.,PARC Inc. | Do T.-O.,University Laval

Hydrogen production via photocatalytic water splitting using sunlight has enormous potential in solving the worldwide energy and environmental crisis. The key challenge in this process is to develop efficient photocatalysts which must satisfy several criteria such as high chemical and photochemical stability, effective charge separation and strong sunlight absorption. The combination of different semiconductors to create composite materials offers a promising way to achieve efficient photocatalysts because doing so can improve the charge separation, light absorption and stability of the photocatalysts. In this review article, we summarized the most recent studies on semiconductor composites for hydrogen production under visible light irradiation. After a general introduction about the photocatalysis phenomenon, typical heterojunctions of widely studied heterogeneous semiconductors, including titanium dioxide, cadmium sulfide and graphitic carbon nitride are discussed in detail. This journal is © The Royal Society of Chemistry. Source

Wang H.,Stanford University | Hsieh B.,PARC Inc. | Jimenez-Oses G.,University of California | Liu P.,University of California | And 5 more authors.

R egioregular poly(3-alkylthiophene) (P3AT) polymers have been previously reported for the selective, high-yield dispersion of semiconducting single-walled carbon nanotubes (SWCNTs) in toluene. Here, fi ve alternative solvents are investigated, namely, tetrahydrofuran, decalin, tetralin, m -xylene, and o- xylene, for the dispersion of SWCNTs by poly(3-dodecylthiophene) P3DDT. The dispersion yield could be increased to over 40% using decalin or o-xylene as the solvents while maintaining high selectivity towards semiconducting SWCNTs. Molecular dynamics (MD) simulations in explicit solvents are used to explain the improved sorting yield. In addition, a general mechanism is proposed to explain the selective dispersion of semiconducting SWCNTs by conjugated polymers. The possibility to perform selective sorting of semiconducting SWCNTs using various solvents provides a greater diversity of semiconducting SWCNT ink properties, such as boiling point, viscosity, and surface tension as well as toxicity. The effi cacy of these new semiconducting SWCNT inks is demonstrated by using the high boiling point and high viscosity solvent tetralin for inkjet-printed transistors, where solvent properties are more compatible with the inkjet printing head and improved droplet formation. © 2014 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim. Source

Burton G.,PARC Inc.
Proceedings of the ASME Design Engineering Technical Conference

In this paper we present a new, efficient algorithm for computing the "raw offset" curves of 2D polygons with holes. Prior approaches focus on (a) complete computation of the Voronoi Diagram, or (b) pair-wise techniques for generating a raw offset followed by removal of "invalid loops" using a sweepline algorithm. Both have drawbacks in practice. Robust implementation of Voronoi Diagram algorithms has proven complex. Sweeplines take O ( (n+k) logn) time and O (n+k) memory, where n is the number of vertices and k is the number of self-intersections of the raw offset curve. It has been shown that k can be O (n2) when the offset distance is greater than or equal to the local radius of curvature of the polygon, a regular occurrence in the creation of contour-parallel offset curves for NC pocket machining. Our O (nlogn) recursive algorithm, derived from Voronoi diagram algorithms, computes the velocities of polygon vertices as a function of overall offset rate. By construction, our algorithm prunes a large proportion of locally invalid loops from the raw offset curve, eliminating all self-intersections in raw offsets of convex polygons and the "near-circular", k proportional to O (n2) worst-case scenarios in non-convex polygons. Copyright © 2014 by ASME. Source

Pandarus V.,PARC Inc. | Gingras G.,PARC Inc. | Beland F.,CNR Institute of Nanostructured Materials | Pagliaro M.,CNR Institute of Nanostructured Materials
Organic Process Research and Development

SiliaCat Pd 0 solid catalyst heterogeneously mediates at room temperature the selective hydrogenation of a wide variety of alkenes under hydrogen balloon conditions using a modest 0.1 mol % catalyst amount. The catalyst is recyclable with negligible leaching of valued palladium, providing the chemical industry with a suitable replacement for less selective metal-based catalysts. © 2012 American Chemical Society. Source

Pandarus V.,PARC Inc. | Ciriminna R.,CNR Institute of Nanostructured Materials | Beland F.,PARC Inc. | Pagliaro M.,CNR Institute of Nanostructured Materials
Advanced Synthesis and Catalysis

A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Discover hidden collaborations