Research on the FE and semi-analytical solution with the blade-casing rub-impact dynamical system

Based on the elasticity theory, a differential equation of forced oscillation of the blade-casing system with rub-impact excitation was deduced, and the steady analytic solution was derived. The analytic solution was verified with the FE (finite element) method, the results indicated that the eigenvalues of dynamical equation by FE method are larger than the semi-analytical method’s, while the vibration modes are identical. Due to the characteristics of rub-impact excitation between the blade and casing, it is not suitable to solve impacting vibrational response for rotating blade with the steady analytic solution. Therefore, the semi-analytical solution was adopted to solve these dynamic problems, which can get the vibration response of any position for its continuity characteristic. Then, the FE and semi-analytical method is used. The comparison of dynamical response with changing speed, rub-impact depth and the friction coefficient was investigated in details. It is found that the speed has the greater effect on the dynamical vibration response, but other parameters affect the response slightly at the same rotational speed. When the friction coefficient and rub-impact depth unchanging, with the increasing speed, the contribution of each multi-frequency component to the resonant response grows obviously, especially the high-harmonic components should be pay more attention. Blade-casing model is easy to form a new resonance system, which will appear different resonant response with the increasing friction coefficient. When the friction coefficient reaches to a certain value, the response amplitude tends to be stable

Nonlinear Dynamic Behavior Analysis of Pressure Thin-Wall Pipe Segment with Supported Clearance at Both Ends

An analysis of nonlinear behaviors of pressure thin-wall pipe segment with supported clearance at both ends was presented in this paper. The model of pressure thin-wall pipe segment with supported clearance was established by assuming the restraint condition as the work of springs in the deformation directions. Based on Sanders shell theory, Galerkin method was utilized to discretize the energy equations, external excitation, and nonlinear restraint forces. And the nonlinear governing equations of motion were derived by using Lagrange equation. The displacements in three directions were represented by the characteristic orthogonal polynomial series and trigonometric functions. The effects of supporting stiffness and supported clearance on dynamic behavior of pipe wall were discussed. The results show that the existence of supported clearance may lead to the changing of stiffness of the pipe vibration system and the dynamic behaviors of the pipe system show nonlinearity and become more complex; for example, the amplitude-frequency curve of the foundation frequency showed hard nonlinear phenomenon. The chaos and bifurcation may emerge at some region of the values of stiffness and clearance, which means that the responses of the pressure thin-wall pipe segment would be more complex, including periodic motion, times periodic motion, and quasiperiodic or chaotic motions

Shoot Organogenesis and Plant Regeneration from Leaf Explants of Lysionotus serratus

The gesneriaceous perennial plant, Lysionotus serratus, has been used in traditional Chinese medicine. It also has a great development potential as an ornamental plant with its attractive foliage and beautiful flowers. An efficient propagation and regeneration system via direct shoot organogenesis from leaf explant was established in this study. High active cytokinin (6-benzyladenine (BA) or thidiazuron (TDZ)) was effective for direct organogenesis of initial induction. Murashige and Skoog (MS) growth media containing 0.5 mg L−1 BA alone or with combination of 0.1 mg L−1  α-Naphthaleneacetic acid (NAA) were the most effective for shoot proliferation. High BA concentration (1.0 mg L−1) in the media caused high percentage of vitrified shoots though they introduced high shoot proliferation rate. Histological observation indicated that adventitious shoot regeneration on the medium containing 0.5 mg L−1 BA alone occurred directly from leaf epidermal cells without callus formation. Regenerated shoots rooted well on medium containing half-strength MS medium with 0.5 mg L−1 indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA), and the plantlets successfully acclimatized and grew vigorously in the greenhouse with a 94.2% and 92.1% survival rate

In Vitro Propagation of Oriental White Oak Quercus aliena Blume

Quercus aliena Blume, also known as the oriental white oak, is a widespread species in temperate forests of East Asia with significant ecological and economical importance. Establishing an efficient vegetative propagation system is important for its germplasm conservation and breeding program. Protocols of micropropagation from shoot tips and nodal segments were investigated in order to produce uniform high-quality seedlings. Nodal segments from 18 month old seedlings were used as explants to initiate the aseptic culture. The highest bud proliferation was achieved by subculturing the explants on 1/2 strength woody plant medium (WPM) with 2.0 mg·L−1 BA. WPM with 0.5 mg·L−1 BA and 0.05 mg·L−1 IBA was the best medium for subculture to obtain the vigorous regenerated shoots in this experiment. Nodal segments without shoot tips had a higher adventitious bud proliferation rate than those with shoot tips. The highest rate (41.5%) of rooting in vitro was induced by using WPM with 1.0 mg·L−1 IBA and 5 g·L−1 activated charcoal. Ex vitro rooting by dipping the proliferated shoots with 500 mg·L−1 IBA solution, then transplanting directly to potting mix with 50% peat and 50% horticultural perlite fostered the highest rooting percentage and survival rate of the plantlets

In Vitro Propagation of Oriental White Oak <i>Quercus aliena</i> Blume

Quercus aliena Blume, also known as the oriental white oak, is a widespread species in temperate forests of East Asia with significant ecological and economical importance. Establishing an efficient vegetative propagation system is important for its germplasm conservation and breeding program. Protocols of micropropagation from shoot tips and nodal segments were investigated in order to produce uniform high-quality seedlings. Nodal segments from 18 month old seedlings were used as explants to initiate the aseptic culture. The highest bud proliferation was achieved by subculturing the explants on 1/2 strength woody plant medium (WPM) with 2.0 mg&#183;L&#8722;1 BA. WPM with 0.5 mg&#183;L&#8722;1 BA and 0.05 mg&#183;L&#8722;1 IBA was the best medium for subculture to obtain the vigorous regenerated shoots in this experiment. Nodal segments without shoot tips had a higher adventitious bud proliferation rate than those with shoot tips. The highest rate (41.5%) of rooting in vitro was induced by using WPM with 1.0 mg&#183;L&#8722;1 IBA and 5 g&#183;L&#8722;1 activated charcoal. Ex vitro rooting by dipping the proliferated shoots with 500 mg&#183;L&#8722;1 IBA solution, then transplanting directly to potting mix with 50% peat and 50% horticultural perlite fostered the highest rooting percentage and survival rate of the plantlets