Subharmonic solution of a vibration system with two mass elastic connecting rods

2019 ◽  
Vol 50 (5) ◽  
pp. 135-142
Author(s):  
Guo Feng
Keyword(s):  
Periodic Motion ◽  
Excitation Frequency ◽  
Melnikov Method ◽  
Periodic Excitation ◽  
Vibration System ◽  
Subharmonic Solution ◽  
Subharmonic Bifurcation ◽  
Double Mass ◽  
Relationship Of ◽  
The Relationship

In this article, the dynamic characteristic of linkage bobbing machine with balanced double-mass bearing periodic excitation and damping is studied. Subharmonic Melnikov function of the oscillating periodic orbits is computed through Melnikov method. And, the relationship of parameters is given when the subharmonic bifurcation occurs. The periodic motion is simulated. Through analysis, as the excitation frequency varies, the periodic motion undergoes flip bifurcations and subharmonic bifurcation occurs, which finally leads to chaos. In addition, the ultra-subharmonic solution of the system is given.

Effects of Different Fast Periodic Excitations on the Pitchfork Bifurcation and Vibrational Resonance

2020 ◽  
Vol 30 (06) ◽  
pp. 2050092
Author(s):  
Jiaqi Zhang ◽  
Jianhua Yang ◽  
Zhencai Zhu ◽  
Gang Shen ◽  
Miguel A. F. Sanjuán
Keyword(s):  
Initial Conditions ◽  
Pitchfork Bifurcation ◽  
Harmonic Excitation ◽  
Bistable System ◽  
Periodic Excitation ◽  
Vibrational Resonance ◽  
Key Factor ◽  
Fast Excitation ◽  
Relationship Of ◽  
The Relationship

We investigate the effects on the pitchfork bifurcation and the vibrational resonance of an overdamped bistable system subjected to both a slow harmonic excitation and a fast periodic excitation with different waveforms. We use numerical simulations along with theoretical explanations to analyze some interesting phenomena. The bifurcation configuration depends closely on the form of the fast excitation. As a result, we have found that the key factor to influence the bifurcation configuration is the symmetry property of the fast excitation. Further, due to the relationship of the vibrational resonance with the pitchfork bifurcation, the vibrational resonance also depends closely on the form of the fast periodic excitation. Moreover, for anharmonic fast excitations, if it is asymmetric, the vibrational resonance usually depends closely on the initial conditions.

Global Bifurcation of a Tuning Mass Damper with Plastic Impacts

2011 ◽  
Vol 243-249 ◽  
pp. 6225-6229
Author(s):  
An Zhi Yan ◽  
Xiao Hua Li
Keyword(s):  
Excitation Frequency ◽  
Global Bifurcation ◽  
Period Doubling ◽  
Tuned Mass Damper ◽  
Gradual Change ◽  
Periodic Excitation ◽  
Vibratory System ◽  
Mass Damper ◽  
The Relationship ◽  
Two Degree Of Freedom

Many Literatures pay attention to the location and parameter optimization of Tuned Mass Damper (TMD). Yet there are few studies on the case where both the TMD and the main system have plastic impacts under large stroke of TMD fixed in limitation space. A two degree-of-freedom (DOF) vibratory system having symmetrically placed rigid stops and subjected to periodic excitation is considered in this paper. The equations of the vibratory system are constructed, and then for simplification the dimensionless equations are obtained. Poincaré map was used to study the relationship between the motion stability and parameters. Period-doubling bifurcation of motion was found by numerical simulations. With the gradual change in excitation frequency, the routes of quasi-periodic impact motions to chaos are observed from simulation results.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

Severe Paradoxical Dysphonia in Two Young Women

1993 ◽  
Vol 2 (3) ◽  
pp. 52-55 ◽  
Author(s):  
Michael Collins ◽  
Robert McDonald ◽  
Robert Stanley ◽  
Timothy Donovan ◽  
C. Frank Bonebrake
Keyword(s):  
Young Women ◽  
Theoretical Basis ◽  
Therapeutic Regimen ◽  
Instrumental Data ◽  
Relationship Of ◽  
The Relationship

This report describes an unusual and persistent dysphonia in two young women who had taken a therapeutic regimen of isotretinoin for intractable acne. We report perceptual and instrumental data for their dysphonia, and pose a theoretical basis for the relationship of dysphonia to this drug. We also provide recommendations for reducing the risk of acquiring a dysphonia during the course of treatment with isotretinoin.

Establishing a Group Educational Session for Hyperacusis Patients

2019 ◽  
Vol 28 (2) ◽  
pp. 245-250
Author(s):  
Ann E. Perreau ◽  
Richard S. Tyler ◽  
Patricia C. Mancini ◽  
Shelley Witt ◽  
Mohamed Salah Elgandy
Keyword(s):  
Therapeutic Process ◽  
Treatment Options ◽  
Clinical Group ◽  
Education Session ◽  
Group Approach ◽  
Treatment Protocols ◽  
Educational Session ◽  
Evidence Based Treatment ◽  
Relationship Of ◽  
The Relationship

Purpose Audiologists should be treating hyperacusis patients. However, it can be difficult to know where to begin because treatment protocols and evidence-based treatment studies are lacking. A good place to start in any tinnitus and hyperacusis clinic is to incorporate a group educational session. Method Here, we outline our approach to establishing a hyperacusis group educational session that includes specific aspects of getting to know each patient to best meet their needs, understanding the problems associated with hyperacusis, explaining the auditory system and the relationship of hyperacusis to hearing loss and tinnitus, describing the influence of hyperacusis on daily life, and introducing treatment options. Subjective responses from 11 adults with hyperacusis, who participated in a recent clinical group education session, were discussed to illustrate examples from actual patients. Conclusions Due to the devastating nature of hyperacusis, patients need to be reassured that they are not alone and that they can rely on audiologists to provide support and guidance. A group approach can facilitate the therapeutic process by connecting patients with others who are also affected by hyperacusis, and by educating patients and significant others on hyperacusis and its treatment options. Supplemental Material https://doi.org/10.23641/asha.8121197

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