Rensselaer Polytechnic Institute

About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Finite element method. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

Crustal motion in Indonesia from Global Positioning System measurements

Abstract: Terrestrial Reference Frame 2000. We compute poles of rotation for the Australia, Eurasia, and Pacific plates based on our analysis of the global GPS data. We find that regional tectonics is dominated by the interaction of four discrete, rotating blocks spanning significant areas of the Sunda Shelf, the South Banda arc, the Bird’s Head region of New Guinea, and East Sulawesi. The largest, the Sunda Shelf block (SSH), is estimated to be moving 6 ± 3 mm/yr SE relative to Eurasia. The South Banda block (SBB) rotates clockwise relative to both the SSH and Australia plate, resulting in 15 ± 8 mm/yr of motion across the Timor trough and 60 ± 3 mm/yr of shortening across the Flores Sea. Southern New Guinea forms part of the Australia plate from which the Bird’s Head block (BHB) moves rapidly WSW, subducting beneath the Seram trough. The East Sulawesi block rotates clockwise about a nearby axis with respect to the Sunda Shelf, thereby transferring east-west shortening between the Pacific and Eurasia plates into north-south shortening across the North Sulawesi trench. Except for the Sunda Shelf, the crustal blocks are all experiencing significant internal deformation. In this respect, crustal motion in those regions does not fit the microplate tectonics model. INDEX TERMS: 1206 Geodesy and Gravity: Crustal movements—interplate (8155); 1243 Geodesy and Gravity: Space geodetic surveys; 8150 Tectonophysics: Plate boundary—general (3040); 8158 Tectonophysics: Plate motions—present and recent (3040); 9320 Information Related to Geographic Region: Asia; KEYWORDS: crustal motion, Indonesia tectonics, GPS, current plate motions, Southeast Asia

Tunable bandgap in graphene by the controlled adsorption of water molecules.

Abstract: Graphene, a single-atom-thick layer of sp 2 -hybridized carbon atoms, has generated considerable excitement in the scientifi c community due to its peculiar electronic band structure, which leads to unusual phenomena such as the anomalous quantum Hall effect, [ 1,2 ] spin-resolved quantum interference, [ 3 ] ballistic electron transport, [ 4 ] and bipolar supercurrent. [ 5 ] However, pristine graphene is a semimetal with zero bandgap; the local density of states at the Fermi level is zero and conduction can only occur by the thermal excitation of electrons. [ 2 ] This lack of an electronic bandgap is the major obstacle limiting the utilization of graphene in nano-electronic and -photonic devices, [ 6,7 ] such as p–n junctions, transistors, photodiodes, and lasers. The graphene band structure is sensitive to lattice symmetry and several methods have been developed to break this symmetry and open an energy gap. These methods are based on a variety of techniques, such as defect generation, [ 8 ] doping (e.g., with potassium [ 9 ] ), applied bias, [ 10–12 ] and interaction with gases [ 13 ] (e.g., nitrogen dioxide). For instance, in reference [ 12 ] a tunable bandgap of up to 0.25 eV was achieved for electrically gated bilayer graphene by a variable external electric fi eld. Similarly, an internal electric fi eld produced by an imbalance of doped charge between two graphene layers has been shown to open a bandgap. [ 9 ] It has been demonstrated that a gap of ≈ 0.26 eV can be produced by growing graphene epitaxially on silicon carbide substrates. [ 14 ] This gap originated from the breaking of sublattice symmetry due to the graphene–substrate interaction. Patterned adsorption of atomic hydrogen onto the Moire superlattice positions of graphene [ 15 ] has resulted in a bandgap of ≈ 0.73 eV opening, while half-hydrogenated graphene [ 16 ] resulted in a bandgap of ≈ 0.43 eV. A graphene nanomesh structure [ 17 ] has also been shown to exhibit a bandgap. In this graphene structure, lateral quantum confi nement and localization effects due to

Strongly Enhanced Phosphor Efficiency in GaInN White Light-Emitting Diodes Using Remote Phosphor Configuration and Diffuse Reflector Cup

Abstract: Enhancement of phosphor efficiency is reported for GaInN-based white light-emitting diodes (LEDs) employing a large separation between the primary LED emitter and the wavelength converter, and a diffuse reflector cup. Ray-tracing simulations show that extraction efficiency of wavelength-converted light is enhanced by 75%. The experimental improvement in phosphor efficiency of blue-pumped yellow phosphor is 15.4% compared with conventional phosphor-based white LEDs. The improvement is attributed to reduced re-absorption of wavelength-converted light by the LED chip.

Intelligent robotic control

Abstract: A theoretical approach is developed to deal with man-machine interactive systems requiring advanced decision making in unpredictable environments. The hierarchical method consists of a three-layer control of "increasing intelligence and decreasing precision." The lowest level consists of several controllers designed for effective control with existing hardware using an approximation theory of optimal control. The next level is that of a coordinator which utilizes new computer architectures to effectively control the overall hardware system. The highest level is the organizer which supervises the performance of the overall system. Both highest levels are computer implemented and the research involved is in developing the appropriate architecture and software to accommodate others. The lowest level, aimed for end-point control tasks, is dominated by typical hardware control methods. The coexistence of the two approaches makes the method novel. Application of intelligent control techniques to robotics and manipulative systems is considered.

Transmission Network Planning Using Linear Programming

Abstract: In long range transmission planning, where new load growth, new generation sites and perhaps a new voltage level are to be considered, a computer aided method of visualizing new circuits in a network context is needed. The new method presented meets this need by the combined use of a linear (dc) power flow transmission model and a transportation model (also known as a trans-shipment model). The dc transmission model is solved for the facilities network by obeying both of Kirchhoff's laws, flow conservation at each bus and voltage conservation around each loop. The transportation model is solved for the overloads by obeying only the bus flow conservation law while minimizing a cost objective function.