1,877 research outputs found
Performance Evaluation of Vision-Based Algorithms for MAVs
An important focus of current research in the field of Micro Aerial Vehicles
(MAVs) is to increase the safety of their operation in general unstructured
environments. Especially indoors, where GPS cannot be used for localization,
reliable algorithms for localization and mapping of the environment are
necessary in order to keep an MAV airborne safely. In this paper, we compare
vision-based real-time capable methods for localization and mapping and point
out their strengths and weaknesses. Additionally, we describe algorithms for
state estimation, control and navigation, which use the localization and
mapping results of our vision-based algorithms as input.Comment: Presented at OAGM Workshop, 2015 (arXiv:1505.01065
Mental Health Matters: College Student Mental Health in the Twenty-First Century
Authors present the content, delivery, and benefits of a one-semester honors college lecture series on college student mental health
Integrated Diamond Optics for Single Photon Detection
Optical detection of single defect centers in the solid state is a key
element of novel quantum technologies. This includes the generation of single
photons and quantum information processing. Unfortunately the brightness of
such atomic emitters is limited. Therefore we experimentally demonstrate a
novel and simple approach that uses off-the-shelf optical elements. The key
component is a solid immersion lens made of diamond, the host material for
single color centers. We improve the excitation and detection of single
emitters by one order of magnitude, as predicted by theory.Comment: 10 pages, 3 figure
A new approach to functional and software structure for engine management systems
ABSTRACT This paper describes the new Engine Management System (EMS) ME7. Torque and A/F demands for modern EMS result from both, internal functions (i.e. engine start, idle speed control, catalyst heating) and external systems (i.e. driver's request, transmission or vehicle dynamic control). With ME7 these demands are processed to the optimized actions of the actuators by a centrally coordinated torque and A/F management. The design of the functions is physically based to provide optimum portability and minimum calibration time. Examples are given for the physical manifold pressure model and the cylinder charge control of ME7 with electronic throttle control. The real time operating system "ERCOS" and a layer based software architecture enable the implementation of these functions in a flexible family of products for current and future systems. Topics, such as warm-up strategies for catalysts in conventional port injection systems, gasoline direct injection systems (with their switch-over strategies between stoichiometric and stratified operation), NOx catalyst control, and the requirements of future integrated drive train management systems, all require maximum flexibility and expandability. The introduction of the ME7 is an important step towards this future. The design represents a good basis for development sharing with customers and is also an important prerequisite for the vehicle management system CARTRONIC
Oxy-functionalization of nucleophilic rhenium(I) metal carbon bonds catalyzed by selenium(IV)
We report that SeO_2 catalyzes the facile oxy-functionalization of (CO)_5Re(I)-Me^(ÎŽâ) with IO_4â to generate methanol. Mechanistic studies and DFT calculations reveal that catalysis involves methyl group transfer from Re to the electrophilic Se center followed by oxidation and subsequent reductive functionalization of the resulting CH_3Se(VI) species. Furthermore, (CO)_3Re(I)(Bpy)-R (R = ethyl, n-propyl, and aryl) complexes show analogous transfer to SeO_2 to generate the primary alcohols. This represents a new strategy for the oxy-functionalization of MâR^(ÎŽâ) polarized bonds
Benzene CâH Bond Activation in Carboxylic Acids Catalyzed by O-Donor Iridium(III) Complexes: An Experimental and Density Functional Study
The mechanism of benzene CâH bond activation by [Ir(ÎŒ-acac-O,O,C^3)(acac-O,O)(OAc)]_2 (4) and [Ir(ÎŒ-acac-O,O,C^3)(acac-O,O)(TFA)]_2 (5) complexes (acac = acetylacetonato, OAc = acetate, and TFA = trifluoroacetate) was studied experimentally and theoretically. Hydrogenâdeuterium (H/D) exchange between benzene and CD_(3)COOD solvent catalyzed by 4 (ÎH^⥠= 28.3 ± 1.1 kcal/mol, ÎS^⥠= 3.9 ± 3.0 cal K^(â1) mol^(â1)) results in a monotonic increase of all benzene isotopologues, suggesting that once benzene coordinates to the iridium center, there are multiple H/D exchange events prior to benzene dissociation. B3LYP density functional theory (DFT) calculations reveal that this benzene isotopologue pattern is due to a rate-determining step that involves acetate ligand dissociation and benzene coordination, which is then followed by heterolytic CâH bond cleavage to generate an iridium-phenyl intermediate. A synthesized iridium-phenyl intermediate was also shown to be competent for H/D exchange, giving similar rates to the proposed catalytic systems. This mechanism nicely explains why hydroarylation between benzene and alkenes is suppressed in the presence of acetic acid when catalyzed by [Ir(ÎŒ-acac-O,O,C^3)(acac-O,O)(acac-C^3)]_2 (3) (Matsumoto et al. J. Am. Chem. Soc. 2000, 122, 7414). Benzene H/D exchange in CF_(3)COOD solvent catalyzed by 5 (ÎH^⥠= 15.3 ± 3.5 kcal/mol, ÎS^⥠= â30.0 ± 5.1 cal K^(â1) mol^(â1)) results in significantly elevated H/D exchange rates and the formation of only a single benzene isotopologue, (C_(6)H_(5)D). DFT calculations show that this is due to a change in the rate-determining step. Now equilibrium between coordinated and uncoordinated benzene precedes a single rate-determining heterolytic CâH bond cleavage step
- âŠ