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Autonomous formation flight is a key approach for reducing energy cost and managing traffic in future high density airspace. The use of Unmanned Aerial Vehicles (UAVs) has allowed low-budget and low-risk validation of autonomous formation flight concepts. This paper discusses the implementation and flight testing of nonlinear dynamic inversion (NLDI) controllers for close formation flight (CFF) using two distinct UAV platforms: a set of fixed wing aircraft named “Phastball” and a set of quadrotors named “NEO.” Experimental results show that autonomous CFF with approximately 5-wingspan separation is achievable with a pair of low-cost unmanned Phastball research aircraft. Simulations of the quadrotor flight also validate the design of the NLDI controller for the NEO quadrotors. [ABSTRACT FROM AUTHOR]

The self-assembly of the precatalyst modules, which are amino acids and cinchona alkaloid derivatives, leads to the direct formation of the desired organocatalysts without any synthesis. These modularly designed organocatalysts (MDOs) may be used for catalyzed asymmetric aldol reaction. Depending on structure of the aldehyde substrates, the corresponding aldol products may be obtained in mediocre to excellent ee values (up to 92% ee) with moderate diastereoselectivities (up to 79:21 dr). [ABSTRACT FROM AUTHOR]

Within the finite‐field Kohn–Sham framework, static electric response properties of diatomic molecules are presented. The electronic energy, dipole moment (μ), static dipole polarizability (α), and first‐hyperpolarizability (β) are calculated through a pseudopotential‐DFT implementation in Cartesian coordinate grid, developed in our laboratory earlier. We engage the Labello–Ferreira–Kurtz (LFK) basis set; while four local and nonlocal exchange‐correlation (LDA, BLYP, PBE, and LBVWN) functionals have been adopted. A detailed analysis of grid convergence and its impact on obtained results is presented. In each case the electric field optimization was carefully monitored through a recently prescribed technique. For all three molecules (HCl, HBr, HI) considered, the agreement of all these quantities with widely successful and popular atom‐centered‐grid procedure, is excellent. To assess the efficacy and feasibility, companion calculations are performed for these on a representative molecule (HCl) at distorted geometries, far from equilibrium. Wherever possible, relevant comparison is made with available all‐electron data and experimental results. This demonstrates that Cartesian grid provides accurate, reliable results for such properties of many‐electron systems within pseudopotential representation. Static electric response properties of three diatomic molecules are calculated using finite‐field Kohn–Sham method within pseudopotential approximation in Cartesian grid. Effect of electric field strength is monitored by evaluating relative error for different exchange‐correlation functionals. Spatial grid optimization and electric field optimization are analyzed in detail. Extension of the method is made at distorted geometry far from equilibrium. This demonstrates that Cartesian grid can provide viable alternative for such properties within DFT. [ABSTRACT FROM AUTHOR]

An abstract of the article "Highly Diastereoselective Palladium-Catalyzed Indium-Mediated Allylation of Chiral Hydrazones" by Narayanaganesh Balasubramanian, Tanmay Mandal, and Gregory R. Cook, is presented.

In the title compound, C(10)H(22)NO(6)P, a staggered conformation is found when the mol-ecule is viewed down the central P-C bond, with the oxo and hydr-oxy groups gauche to each other. The crystal structure features supra-molecular chains of helical topology propagating along the b axis, mediated by O-H⋯O hydrogen bonds.

In the title compound, C(14)H(21)FNO(6)P, a staggered conformation about the central P-C bond occurs, with the oxo and hydroxyl groups occupying diagonally opposite positions. The crystal structure features supra-molecular chains mediated by O-H⋯O hydrogen bonds, which propagate in the a-axis direction. A C-H⋯O inter-action consolidates the chains. Disorder was resolved for one of the isopropyl groups with a 0.60 (2):0.40 (2) occupancy ratio for the two components.

Enantioenriched 2,3,4-trisubstituted thiochromanes have been synthesized by using a cupreine-catalyzed tandem Michael addition-Henry reaction between 2-mercaptobenzaldehydes and β-nitrostyrenes. Good diastereoselectivities and enantioselectivities were obtained for the title compounds, which may be further improved through a single recrystallization (up to 98% de and> 99% ee).