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91.
Nonlinear Dynamics - In this article, the authors simulate and study dark and bright soliton solutions of 1D and 2D regularized long wave (RLW) models. The RLW model occurred in various fields such... 相似文献
92.
The stability and control characteristics of two twin-lift helicopter configurations are analyzed in this paper. In order to address the issue of configuration selection from a handling qualities viewpoint, their open-and closed-loop characteristics are compared. The two twin-lift configurations considered are the twin-lift with spreader bar and twin-lift without spreader bar. The nonlinear models describing the dynamics of these two configurations in the lateral/vertical plane are derived. The open-loop characteristics of the two systems are compared by linearizing the nonlinear models about a symmetric hovering equilibrium condition. The closed-loop characteristics of the two systems are compared using nonlinear controllers based on feedback linearization schemes. The performance of the resulting closed-loop systems in carrying out a typical twin-lift mission is evaluated through nonlinear simulation. Also, the effects of helicopter performance degradation and measurement errors on the overall system performance are discussed.[B] Matrix multiplying the control vector in the nonlinear model[B1] Matrix multiplying the control vector in the linear model[C] Matrix defining vector of variables to be controlled[C1] Damping matrixCijElement of the damping matrix
e Parameter used in the linear model = M
1
h
1/I
1=M
2
h
2/I
2,/ft{f} Vector independent of controls in the nonlinear model
g Acceleration due to gravity, ft/sec2
h1, h2Distance of tether attachment point to the center of gravity for helicopters 1 and 2, ft
h Parameter used in the linear model, =h
1=h
2, ft
h Distance between rotor hub and the helicopter center of gravity, ft
h h/l
H Distance of the load from the spreader bar c.g., ftH1, H2Length of tethers 1 and 2, ftIRMass moment of inertia of spreader bar, slug-ft2
I1, I2Roll moments of inertia of helicopters 1 and 2, slug-ft2
k Non-dimensional hub control moment coefficientKDDerivative gainsKIIntegral gainsKPProportional gains[Ki] Stiffness matrixKijElement of the stiffness matrix
l Parameter used in the linear model, =H
1=H
2, ft
L Spreader bar length, ftNomenclature 相似文献
93.
M. Sc. Indrajit Paul M. Sc. Abir Goswami M. Sc. Nikita Mittal Prof. Dr. Michael Schmittel 《Angewandte Chemie (International ed. in English)》2018,57(1):354-358
Three supramolecular slider‐on‐deck systems DS1 – DS3 were obtained as two‐component aggregates from the sliders S1 – S3 and deck D with its three zinc porphyrin (ZnPor) binding sites. The binding of the two‐footed slider to the deck varies with the donor qualities of and the steric hindrance at the pyridine/pyrimidine (pyr) feet, and was effected by two Npyr→ZnPor interactions. Accordingly, the sliders move over the three zinc porphyrins in the deck at different speeds, namely with 32.2, 220, and 440 kHz at room temperature. The addition of N‐methylpyrrolidine as an organocatalyst to DS1 – DS3 generates catalytic three‐component machineries. By using a conjugate addition as a probe reaction, we observed a correlation between the operating speed of the slider‐on‐deck systems and the yields of the catalytic reaction. As the thermodynamic binding of the slider decreases, both the frequency of the sliding motion and the yield of the catalytic reaction increase. 相似文献
94.
The production of macroporous monoliths functionalized with a thermo‐responsive polymer (PNIPAAM) is described. The surface functionalization was achieved by copolymerization of acrylic end capped atom transfer radical polymerization initiator (BPOEA) with divinylbenzene with or without styrene. Monoliths were generated by swelling them with styrene, BPOEA and divinylbenzene followed by gelation with salt and post polymerization. Subsequent grafting of these monoliths with PNIPAAM was achieved by atom transfer radical polymerization and their swelling deswelling characteristics quantified. The grafted monoliths provide a unique chromatographic stationary phase where adsorption/desorption can be driven by the use of temperature only.
95.
Adsorption of basic fuchsin using waste materials--bottom ash and deoiled soya--as adsorbents 总被引:1,自引:0,他引:1
Basic fuchsin, a triaminotriphenylmethane dye, was removed by adsorption utilizing two waste materials--"bottom ash," a power plant waste material, and "deoiled soya," an agriculture waste product. The adsorbents were characterized through IR spectroscopy and differential thermal analysis (DTA). Batch adsorption experiments were carried out by measuring effects of pH, adsorbate concentration, sieve size, amount of adsorbent, contact time, temperature, etc. The results have been verified on the basis of Langmuir and Freundlich adsorption isotherm models and data obtained have been applied to calculate thermodynamic parameters. Specific rate constants for the processes were calculated by kinetic measurements and a pseudo-second-order adsorption kinetics was observed in each case. To identify whether the ongoing process is particle diffusion or film diffusion, the treatment given by Boyd and Reichenberg was employed. To assess the practical utility of the adsorbent, the aqueous adsorbate samples were eluted through fixed-bed columns of respective adsorbents. Attempts were also made to recover the adsorbed dyes by passing suitable solvent through the columns. 相似文献
96.
Lele PP Mittal M Furst EM 《Langmuir : the ACS journal of surfaces and colloids》2008,24(22):12842-12848
We study the transition of ordered structures to disordered bands and vortices in colloidal suspensions subjected to AC electric fields. We map the critical frequencies and field biases at which particles form disordered bands and vortices. These results are interpreted based on the trajectory dynamics of particle pairs using blinking optical tweezers. Under conditions that vortices are observed, individual particle pairs rotate out of alignment with the field. The direction and magnitude of these interactions determine the orientation and average angular velocity of the band revolution. Increasing the frequency of the electric field reduces the anomalous rotation of the particles pairs, consistent with the frequency dependence of the suspension order-to-disorder transition. This anomalous rotation is consistent with a torque on doublets generated by the mutual polarization of particles and phase lag of the induced dipoles. 相似文献
97.
Sulekh?ChandraEmail author Archana?Gautam Monika?Tyagi 《Transition Metal Chemistry》2007,32(8):1079-1084
Cobalt(II), nickel(II) and copper(II) complexes are synthesized with 1,3,7,9-tetraaza- 4,6,10,12-tetraphenyl-2,8-dithiacyclododecane,
a tetradentate ligand (L) and characterized by elemental analysis, molar conductance measurements, magnetic susceptibitity
measurements, mass, i.r., electronic and e.p.r. spectral studies. All the complexes are non-electrolytes so they may be formulated
as [M(L)X2] [where, M = Co(II), Ni(II) and Cu(II) and X = Cl− and NO
3
−
]. All the complexes are of high spin type. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry
has been assigned for Co(II) and Ni(II) complexes and tetragonal geometry for Cu(II) complexes. The antimicrobial activities
of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against two different species of bacteria and plant pathogenic fungi. 相似文献
98.
99.
Different molar reactions of Fe(OPr1)3, and FeCl3 with benzothiazolines having an NSH donor system. derived by the condensation ofo-aminothiophenol with heterocyclic aldehydes. viz. pyridine-2-aldehyde. furfuraldehyde and thiophene-2-aldehyde. lead to the
formation of [Fe.Pr1(NS)2]2, [Fc(NS)3] and [Fe(NS)2Cl| type of complexes. The resulting derivatives have been characterized by elemental analysis, conductivity measurements,
molecular weight determinations and magnetic studies. IR, electronic, M?ssbauer and ESR spectral data have been used to deduce
the structures of the resulting derivatives. 相似文献
100.