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1.
The difference between the classical treatment offlexible body impact and the treatment of impact in flexiblemultibody dynamics is due to several fundamental reasons. Inthe classical impact theory, simple structures such as beamsand plates are used. Infinite dimensional models can bedeveloped for these simple structural elements to study theimpact dynamics and the wave propagation problem. Flexiblemultibody impact problems, on the other hand, involve bodieswith complex geometry that cannot be modeled using infinitenumber of degrees of freedom. Furthermore, the classicalimpact theory has been mainly concerned with the impactbetween a rigid mass that moves without constraints beforeit impacts a simple flexible structure. This is not amultibody simulation scenario in which the impact occursbetween kinematically constrained bodies that are subjectedto impulsive constraint forces in addition to the impactforces. These constraint forces can influence the motion ofthe two bodies immediately after impact, and as aconsequence, the simple classical theory scenario of impactdoes not apply. It is the objective of this paper to discussthe use of the restitution condition in flexible multibodyimpact problems and demonstrate that the use of thisapproach does not exclude the classical formulation.Nonetheless, the impulse momentum balance approach can serveas an effective and efficient procedure for solving theimpact problem in finite dimensional models that do not obeythe classical wave theory. Energy results of simplestructural elements are presented in order to demonstratethe consistency of using the impulse momentum balanceapproach in solving impact problems in finite dimensionalflexible body applications. 相似文献
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Iván Escalona Edgar Del Carpio Lino Hernández Vito Lubes 《Journal of solution chemistry》2014,43(6):1001-1010
In this work, the ternary complex formation among copper(II), 6-methylpicolinic acid (H6Mepic) as primary ligand, and the amino acids aspartic acid (H2Asp), glutamic acid (H2Glu) and histidine (HHis) as secondary ligands, were studied in aqueous solution at 25 °C using 1.0 mol·dm?3 KNO3 as the ionic medium. Analysis of the potentiometric data using the least squares computational program LETAGROP indicates formation of the species [Cu(6Mepic)]+, Cu(6Mepic)(OH), [Cu(6Mepic)(OH)2]?, Cu(6Mepic)2 and [Cu(6Mepic)3]? in the binary Cu(II)–H6Mepic system. In the ternary Cu(II)–H6Mepic–H2Asp system the complexes [Cu(6Mepic)(H2Asp)]+, Cu(6Mepic)(HAsp), [Cu(6Mepic)(Asp)]? and [Cu(6Mepic)(Asp)(OH)]2? were observed. In the case of the Cu(II)–H6Mepic–H2Glu system the complexes Cu(6Mepic)(HGlu), [Cu(6Mepic)(Glu)]?, [Cu(6Mepic)(Glu)(OH)]2? and [Cu(6Mepic)(glu)(OH)2]3? were detected. Finally, in the Cu(II)–H6Mepic–HHis system the complexes [Cu(6Mepic)(HHis)]+, Cu(6Mepic)(His) and [Cu(6Mepic)(His)(OH)]? were observed. The species distribution diagrams as a function of pH are briefly discussed. 相似文献
3.
Castro Jorge Fernández Francisco Olivares Felipe Berríos Cristhian Garrido-Ramírez Elizabeth Blanco Elodie Escalona Néstor Aspée Alexis Barrías Pablo Ureta-Zañartu M. Soledad 《Journal of Solid State Electrochemistry》2021,25(1):117-131
Journal of Solid State Electrochemistry - 2,4,6-trichlorophenol (TCP) is a persistent pollutant introduced in water by industrial processes and pesticides. We have studied the electrooxidation of... 相似文献
4.
Efficient Evaluation of the Elastic Forces and the Jacobian in the Absolute Nodal Coordinate Formulation 总被引:1,自引:0,他引:1
This paper develops a new procedure for evaluating the elastic forces, the elastic energy and the jacobian of the elastic
forces in the absolute nodal coordinate formulation. For this procedure, it is fundamental to use some invariant sparse matrices
that are integrated in advance and have the property of transforming the evaluation of the elastic forces in a matrix multiplication
process. The use of the invariant matrices avoids the integration over the volume of the element for every evaluation of the
elastic forces. Great advantages can be achieved from these invariant matrices when evaluating the elastic energy and calculating
the jacobian of the elastic forces as well. The exact expression of the jacobian of the differential system of equations of
motion is obtained, and some advantages of using the absolute nodal coordinate formulation are pointed out. Numerical results
show that there is important time saving as a result of the use of the invariant matrices. 相似文献
5.
F. J. Gil Llambías N. Escalona C. Pfaff C. Scott J. Goldwasser 《Reaction Kinetics and Catalysis Letters》1999,66(2):225-229
Apparent surface coverage (ASC) of a series of tungsten-alumina catalysts was determined by the electrophoretic migration
method (EM). A linear increase in W coverage with increasing W loading (up to 13.1 wt.% W) was observed. The results were
in close agreement with those obtained previously by ion scattering spectroscopy (ISS) and low temperature CO adsorption. 相似文献
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Silvia del Carmen Molina Bertrn Lianet Monzote Davie Cappoen Julio Cesar Escalona Arranz Mario Juan Gordillo Prez Annarli O. Rodríguez-Ferreiro Idelsy Chill Nuez Claudina Prez Novo Daniel Mndez Paul Cos Gabriel Llaurad Maury 《Molecules (Basel, Switzerland)》2022,27(15)
The increase in antibiotic resistance demands innovative strategies to combat microorganisms. The current study evaluated the antibacterial and antivirulence effects of ethanol extracts from Persea americana seeds obtained by the Soxhlet (SE) and maceration (MaE) methods. The UHPLC-DAD-QTOF analysis showed mainly the presence of polyphenols and neolignan. Ethanol extracts were not cytotoxic to mammalian cells (CC50 > 500 µg/mL) and displayed a moderate antibacterial activity against Pseudomonas aeruginosa (IC50 = 87 and 187 µg/mL) and Staphylococcus aureus (IC50 = 144 and 159 µg/mL). Interestingly, no antibacterial activity was found against Escherichia coli. SE and MaE extracts were also able to significantly reduce the bacterial adhesion to A549 lung epithelial cells. Additionally, both extracts inhibited the biofilm growth at 24 h and facilitated the release of internal cell components in P. aeruginosa, which might be associated with cell membrane destabilization. Real-time PCR and agarose electrophoresis gel analysis indicated that avocado seed ethanol extracts (64 µg/mL) downregulated virulence-related factors such as mexT and lasA genes. Our results support the potential of bioproducts from P. americana seeds as anti-adhesive and anti-biofilm agents. 相似文献
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The use of inductively coupled plasma optimal emission spectroscopy as a detector for the high-performance liquid chromatographic analysis of inositol phosphates is studied. It is found that separation of different inositol phosphates with a mobile phase consisting of tetraethylammonium (0.14%, w/v), methanol (5%, v/v), and formic acid (0.18%, w/v) may be obtained on a PRP-1 column with an analysis time of 18 min. In addition, high specificity and sensitivity of the detection system used permits detection of the inositol phosphates from bi- to hexaphosphate free from interference of other chromatographic peaks, which could be from the sample or mobile phase. Additionally, it is possible to use less sample because of the high sensitivity of the detection system. 相似文献
10.
J.?ValverdeEmail author J.?L.?Escalona E.?Freire J.?Domínguez 《Nonlinear dynamics》2005,42(2):137-163
In this paper, a modified Jeffcott model is proposed and studied in order to shed light into the dynamics of a complex system,
the Short Electrodynamic Tether (SET), which is similar to an unbalanced rotor. Due to the internal damping, a geometrically
linear SET model appears to be unstable as predicted by the linear rotordynamics theory. Some studies in the field of rotordynamics
suggest that this instability caused by internal damping do not appear if geometric nonlinearities are taken into account
in the system equations of motion. Stability and bifurcation analysis have been carried out on the modified Jeffcott model,
which accounts for geometric nonlinearities, orthotropy in the shaft's cross section, and a viscous damping-based internal
damping model. The stability results analytically obtained have been compared with a nonlinear multibody model by means of
time simulations and good agreement has been found. 相似文献