9,9-Dimethyl-12-phenyl-8,9-dihydro-12H-benzo[a]xanthen-11(10H)-one

The title compound, C25H22O2, was synthesized via the three-component coupling of benzaldehyde, 2-naphthol and 5,5-dimethyl­cyclo­hexane-1,3-dione. In the crystal structure, centrosymmetrically related mol­ecules are linked into dimers by pairs of inter­molecular C—H⋯O hydrogen bonds. The dimers are further connected into a three-dimensional network by π–π aromatic stacking inter­actions involving the naphthalene ring system, with centroid–centroid separations of 3.695 (7) Å

Numerical simulation for machining S-tube by abrasive flow with various particle volume fractions

Abrasive flow machining has become an economical and efficient ultra-precision process for machining complex-shaped pipe parts, and processing effect is exceedingly subject to particle volume fraction. In this paper, aiming at uncovering the influence of various particle volume fractions on the machining result of abrasive flow finishing, based on fluid mechanics theory, mixed phase model and discrete phase model were conducted, FLUENT software was resorted to simulate the numerical characteristics of the solid-liquid two-phase flow field in the inner channel of S-tube with different-particle-volume-fraction abrasive flows, the mechanism of erosion and wear of particles was uncovered, which provides a theoretical basis for abrasive flow machining S-tube structured components

Harmonic Analyses of Hydrodynamic Characteristics for Gap Resonance Between Fixed Box and Vertical Wall

Two marine structures arranged side by side with a narrow gap may suffer from violent free-surface resonance, which would cause green water on deck, dramatically raise hydrodynamic loads on structures and seriously threaten the operation safety. The CFD-based open-sourced software, OpenFOAM®, is employed to simulate the two-dimensional fluid resonance inside a narrow gap between a fixed box and a vertical wall induced by regular waves with different wave heights. The topographies with various plane slopes are placed in front of the wall. The focus of this article is on the influences of the incident wave height and the topographic slope on the nonlinear characteristics of various hydrodynamic parameters (including the wave height in the gap, the vertical wave force, and the horizontal wave force on the box) during gap resonance. The ratios of their high-order to the corresponding 1st-order components under different sets of the incident wave height and the topographic slope are analyzed. It is found that the relative importance of all the high-order components increases gradually with the incident wave height for all the three parameters. The topographic influence on them closely depends on the type of the parameters and the incident wave height. In addition, the occurrence of the 2nd-order gap resonance phenomenon can cause the 2nd-order wave height and horizontal force to be significantly larger than the corresponding 1st-order components.</p

4-Benzyl-4-methyl­morpholinium hexa­fluoro­phosphate

In the title compound, C12H18NO+·PF6 −, the asymmetric unit consists of two cation–anion pairs. The six F atoms of one anion are disordered over two sets of sites in a 0.592 (6):0.408 (6) ratio. The morpholinium rings adopt chair conformations

4-Hydroxy­ethyl-4-methyl­morpholinium chloride

In the title compound, C7H16NO2 +·Cl−, the asymmetric unit consists of two cation–anion pairs, in which the ion pairs are inter­connected by weak C—H⋯Cl hydrogen bonds. Each cation forms a network of weak C—H⋯Cl hydrogen bonds to surrounding chloride ions. The morpholine ring is in a chair conformation. The crystal structure is consolidated by O—H⋯Cl, C—H⋯Cl and C—H⋯O inter­molecular hydrogen bonding

3,3,6,6-Tetra­methyl-9-(2-nitro­phen­yl)-3,4,6,7-tetra­hydro-2H-xanthene-1,8(5H,9H)-dione

In the title compound, C23H25NO5, the pyran ring adopts a flattened boat conformation, while the two cyclo­hexenone rings are in envelope conformations. The 3-nitro­phenyl ring is almost perpendicular to the pyran ring, making a dihedral angle of 87.1 (3)°

Bis(acetophenone oxime) O,O′-methyl­ene ether

In the mol­ecule of the title compound, C17H18N2O2, the dihedral angle between the aromatic rings is 74.26 (3)°. The oxime units are oriented at dihedral angles of 7.66 (3) and 33.06 (3)° with respect to the adjacent rings, and they have E configurations about the C=N bonds

4-Allyl-4-ethyl­morpholinium chloride

In the title molecular salt, C9H18NO+·Cl−, the morpholine ring adopts a chair conformation. In the crystal structure, intra­molecular C—H⋯Cl bonds occur and inter­molecular C—H⋯O and C—H⋯Cl hydrogen bonds link the mol­ecules