A thermal boundary control method for a flexible thin disk rotating over critical and supercritical speeds

In practice a rotating flexible thin annular disk has to be operated at low speed, because three types of dynamic instabilities inevitably occur around critical and supercritical speeds, namely: aeroelastic, parametric and thermoelastic. The rotating disk is clamped and driven by a drive shaft attached to the disk inner edge. The external action of the flowing surrounding air causes the aeroelastic instability; a slider mass-damper-spring-friction moving load causes parametric instability; and disk/slider interface friction heat can cause thermoelastic instability. A thermal boundary control method is used to induce disk thermal membrane stresses utilizing drive shaft temperature increments to stabilize these dynamic instabilities. Fundamental investigations are made of disk temperature distribution, thermal stress, natural frequency, dynamic stability and steady state amplitude to validate and demonstrate the viability of the new control method. The thermal boundary control method offers valuable opportunities for rotating disk applications operating over critical and supercritical high speeds with high efficiency

Methyl 9H-carbazole-9-acetate

The title compound, C15H13NO2, was synthesized by N-alkyl­ation of methyl bromo­acetate with 9H-carbazole. The carbazole ring system is essentially planar (mean atomic deviation = 0.0346 Å) and makes a dihedral angle of 86.5 (7)° with the methyl acetate group. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure

Quorum Sensing Activity of Mesorhizobium

We isolated a bacterial isolate (F7) from potable water. The strain was identified as Mesorhizobium sp. by 16S rDNA gene phylogenetic analysis and screened for N-acyl homoserine lactone (AHL) production by an AHL biosensor. The AHL profile of the isolate was further analyzed using high resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) which confirmed the production of multiple AHLs, namely, N-3-oxo-octanoyl-L-homoserine lactone (3-oxo-C8-HSL) and N-3-oxo-decanoyl-L-homoserine lactone (3-oxo-C10-HSL). These findings will open the perspective to study the function of these AHLs in plant-microbe interactions

Research on Dual-Variable Integrated Electro-Hydrostatic Actuator

AbstractThe integrated electro-hydrostatic actuator (EHA) with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotation speed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state space model is created. The system characteristics are studied based on the point of multiplicative dual variable. And the basic method of control of the system is presented

2-(Carbazol-9-yl)acetic acid

In the title compound, C14H11NO2, the tricyclic aromatic ring system is essentially planar [maximum deviation = 0.025 (2) Å]. The dihedral angle between the two benzene rings is 2.8 (5)°, while the carboxyl group forms a dihedral angle of 88.5 (1)° with the pyrrole ring. Inter­molecular O—H⋯O hydrogen bonds may contribute to the overall stabilization of the crystal structure

2-Chloro­ethyl 4-nitro­benzoate

The title compound, C9H8ClNO4, crystallizes with two mol­ecules in the asymmetric unit. In each mol­ecule, the carboxyl­ate group is nearly coplanar with the benzene ring, forming dihedral angles of 2.4 (1) and 4.9 (1)°. In the crystal, mol­ecules are linked through weak C—H⋯O and C—H⋯Cl hydrogen bonds. A short O⋯N contact of 2.7660 (19) Å occurs between the nitro groups of adjacent mol­ecules

5,6,7,8-Tetra­hydro­naphthalene-1-carboxylic acid

In the mol­ecule of the title compound, C11H12O2, the cyclo­hexane ring adopts a half-chair conformation. In the crystal structure, mol­ecules are linked into centrosymmetric dimers by pairs of O—H⋯O hydrogen bonds, and the dimers are linked together by π–π inter­actions [centroid–centroid distance = 3.8310 (13) Å] and C—H⋯O bonds

Dimethyl 5-nitro­isophthalate

The nitro group in the title compound, C10H9NO6, is rotated by 10.9 (5)° out of the plane of the benzene ring

3,5-Dinitro­benzoyl chloride

The carbonyl chloride group in the title compound, C7H3ClN2O5, is disordered over two orientations with occupancies of 0.505 (5) and 0.495 (5). The mol­ecule is approximately planar, the dihedral angle between the carbonyl chloride plane and benzene ring being 9.6 (4)° in the major disorder component and 7.1 (4)° in the minor component. The nitro group at the 5-position is twisted, forming a dihedral angle of 6.7 (4)°. The crystal packing is stabilized by C—H⋯O hydrogen bonds

Ethyl 4-chloro-3,5-dinitro­benzoate

In the title compound, C9H7ClN2O6, the nitro groups and the ester group make dihedral angles of 44.0 (1), 89.6 (1) and 164.1 (1)°, respectively, with the benzene ring. In the crystal, mol­ecules are linked through weak C—H⋯O hydrogen-bonding inter­actions. Mol­ecules are stacked via π–π inter­actions about inversion centers, with a centroid–centroid distance of 3.671 (2) Å