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81.
Jih-Hsing Chang Zhimin Qiang Chin-Pao Huang Amanda V. Ellis 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,348(1-3):157-163
In this study, the remediation performance of electrokinetic (EK) technology integrated with different surfactants for removing phenanthrene from unsaturated soils was investigated. A synthetic surfactant (Triton X-100) and a biosurfactant (rhamnolipid) were used to enhance phenanthrene solubility and removal efficiency during EK process. Results indicate that the electro-osmotic flow (EOF) rate in the rhamnolipid system is higher than that in Triton X-100. Using the EK technology for the removal of phenanthrene in the presence of rhamnolipid was more efficient than in the presence of Triton X-100. In addition to the transport mechanism of phenanthrene in EK system, the presence of rhamnolipid may promote microbial growth in the soil–water system and bring about biodegradation of phenanthrene. A diffusion–advection–sorption (DAS) model was solved by MATLAB, based on the linear sorption isotherm at the non-equilibrium condition, which is feasible to simulate the movement of phenanthrene during the EK + Triton X-100 treatment. 相似文献
82.
Hypotheses from elasticity theory were used for modeling stress distribution in a semi-infinite-homogeneous medium when a point load was applied on its surface. A Concentration factor coefficient was introduced to adapt the equations to the characteristics of the investigated soil. An expression for continuous load distributions and variations in the geometry of the contact area between soil and tire were obtained by means of the superposition principle. Some simulations for different areas and load distributions are discussed and compared with field measurements. 相似文献
83.
84.
Anna Bosi 《Meccanica》2007,42(5):477-485
A wavelet-based methodology for detecting critical events in displacement and temperature histories, obtained by monitoring
in-situ thermoelastic structures, is proposed. It is based on the wavelet analysis of thermoelastic potentials furnishing
also the possibility to detect separately cases in which sudden jumps occur in the displacement history from those in which
they occur on temperature history. 相似文献
85.
86.
A complete closed form vectorial solution to the Kepler problem 总被引:2,自引:0,他引:2
The paper gives an exact vectorial solution to the Kepler problem. A vectorial regularization that linearizes the Kepler problem
is given using a Sundman transformation. Closed form expressions describing the Keplerian motion are deduced. A unified approach
to the classic Kepler problem is offered, by studying both rectilinear and non-rectilinear Keplerian motions with the same
instrument. The approach is an elementary one and only simple vectorial computations are involved. 相似文献
87.
Ultrasound-assisted soil washing processes were investigated for the removal of heavy metals (Cu, Pb, and Zn) in real contaminated soils using HCl and EDTA. The ultrasound-assisted soil washing (US/Mixing) process was compared with the conventional soil washing (Mixing) process based on the mechanical mixing. High removal efficiency (44.8% for HCl and 43.2% for EDTA) for the metals was obtained for the most extreme conditions (HCl 1.0 M or EDTA 0.1 M and L:S = 10:1) in the Mixing process. With the aide of ultrasound, higher removal efficiency (57.9% for HCl and 50.0% for EDTA) was obtained in the same extreme conditions and similar or higher removal efficiency (e.g., 54.7% for HCl 0.5 M and L:S = 10:1 and 50.5% for EDTA 0.05 M and L:S = 5:1) was achieved even in less extreme conditions (lower HCl or EDTA concentration and L:S ratio). Therefore, it was revealed that the US/Mixing was advantageous over the conventional Mixing processes in terms of metal removal efficiency, consumption of chemicals, amount of generated washing leachate, and volume/size of washing reactor. In addition, the heavy metals removal was enhanced for the smaller soil particles in the US/Mixing process. It was due to more violent movement of smaller particles in slurry phase and more violent sonophysical effects. In order to understand the mechanism of ultrasonic desorption, the desorption test was conducted using the paint-coated beads with three sizes (1, 2, and 4 mm) for the free and attached conditions. It was found that no significant desorption/removal of paint from the beads was observed without the movement of beads in the water including floatation, collision, and scrubbing. Thus, it was suggested that the simultaneous application of the ultrasound and mechanical mixing could enhance the physical movement of the particles significantly and the very high removal/desorption could be attained. 相似文献
88.
Jaroslav Menčík 《Meccanica》2007,42(1):19-29
The paper reviews the current state of the depth-sensing indentation (sometimes called nanoindentation), where the information
on material behaviour and properties is obtained from the indenter load and depth, measured continuously during loading and
unloading. It is shown how the contact parameters and principal characteristics are determined using pointed or spherical
indenters. Indentation tests can be used for the measurement of hardness and elastic modulus, and also of the yield stress
and for the construction of stress–strain diagrams, for the determination of the work of indentation and its components. Most
devices use monotonic loading and unloading, but some also enable measurement under a small harmonic signal added to the basic
monotonously increasing load. This makes possible continuous measurement of contact stiffness and the study of dynamic properties
and the determination of properties of coatings. One section is devoted to the measurement on viscoelastic-plastic materials,
where the delayed deforming must be considered during the measurement as well as in data evaluation. Instrumented indentation
can also be used for the study of creep under high temperatures. The paper also discusses the errors arising in depth-sensing
measurements and informs briefly about some other possibilities of the method. 相似文献
89.
Vibration reduction in a flexible-link mechanism through synthesis of an optimal controller 总被引:1,自引:0,他引:1
In this paper, reduction of vibration of a flexible planar mechanism is achieved through synthesis of an optimal controller.
A finite element model, based on the equivalent rigid-link system theory, is used to accurately describe the dynamic behavior
of the system. The model, which accounts for geometric and inertial nonlinearities of the mechanism, has been fully validated
through experimental tests. In order to be able to employ the classical optimal control theory, a suitable linear model has
been derived from the original one by means of a suitable linearization procedure. Vibration reduction can then be obtained
by first defining an adequate performance index, which accounts for vibration amplitude, then by solving Riccati’s equation
in order to find the controller that minimizes the performance index, i.e. the optimal controller. The results of several
tests that have been carried out are also reported, to show the effectiveness of the synthesized control system. 相似文献
90.