bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Hydrostatic Pressurization Increases Matrix Gene Expression by Chondrocytes in 3D Culture
Authors: Mauck Robert L. , Soltz Michael A. , Ateshian Gerard A. , Hung Clark T. 
Published: November 2021

Abstract
Articular cartilage is the load-bearing substance that covers the bony surfaces of articulating bones. With its high water content and small pore size, deformation of cartilage induces a very high hydrostatic pressure within the cartilage. This hydrostatic pressure has been shown both theoretically and experimentally to support upwards of 90% of the applied load (1), and can be on the order of 6–12 MPa. Chondrocytes, the cells within cartilage respond to this pressure by altering their rates of biosynthesis. Studies utilizing radionucleotide incorporation in both explant and monolayer cultures (2–4) have shown that in general dynamic pressurization increases synthesis, while static pressurization decreases synthesis. More recently, Smith et al have shown that dynamic pressurization (10MPa, 1 Hz) of cells in monolayer culture can upregulate matrix gene expression (5,6). Further, a study in PGA constructs has shown that long term application of dynamic pressure can increase matrix deposition (7). In this study, we seek to expand on these findings by examining the response in gene expression of articular chondrocytes encapsulated in alginate, a charged, 3D hydrogel.
Biomechanical Properties of Grown Cartilage Are Decreased in the Presence of Retinoic Acid, Chondroitinase ABC and Ibuprofen
Authors: Chen Chih-Tung , Torzilli Peter A. , Fishbein Kenneth W. , Spencer Richard G. S. , Horton Walter E. 
Published: November 2021

Abstract
The objective of this study was to determine the biomechanical properties of cartilage grown in a hollow-fiber bioreactor and their correlation with biochemical properties and magnetic resonance images (MRT). Engineered/grown cartilage has been shown to be a useful resource for cartilage repair [5]. The integrity and functional strength of engineered tissues are reflected in their biomechanical properties. A better understanding of the biomechanical properties of engineered cartilage can benefit us when designing a system to grow cartilage.
Building Cellular Microenvironments to Control Capillary Endothelial Cell Proliferation, Death, and Differentiation
Authors: Tien Joe , Tan John L. , Nelson Celeste M. , Chen Christopher S. 
Published: November 2021

Abstract
The dynamic binding interactions between cell surface receptors and local bioactive ligands serves as the principal mechanism by which cells survey their microenvironment and accordingly modulate their behaviors, such as proliferation, differentiation, migration, and suicide. Using conventional and non-conventional microfabrication approaches to engineer well-defined cellular microenvironments, we are examining how cells recognize and respond to adhesive interactions with the insoluble extracellular matrix (ECM). We will discuss our approaches to control the architecture and geometry of the adhesive interactions, as well as our resulting progress in identifying and elucidating the mechanisms by which cells sense the physical, chemical, and structural information carried within the ECM. By developing these approaches to engineering cell-surface interactions, we hope to improve the interconnect between artificial surfaces and living cells.
Strain and Strain Rate Dependence of Vascular Smooth Muscle Injury
Authors: Barbee Kenneth A. , Bhavnani Amit 
Published: November 2021

Abstract
Over 350,000 percutaneous translumenal coronary angioplasty (balloon angioplasty) procedures are performed each year. This procedure offers a less invasive alternative to coronary by-pass surgery for patients whose coronary vessels have become occluded due to the process of atherosclerosis. Its potential has not been fully realized due to the high rate of restenosis — the rapid reocclusion of the vessel due to the pathological growth of the vascular smooth muscle (VSM) in response to the trauma of the balloon inflation. Despite the recognition of smooth muscle injury as an initiating event in the process of restenosis, there has been no systematic study to determine the mechanical loading conditions required to produce VSM injury and elicit the restenosis response. In this study, a cell culture model was developed to define the loading conditions required to produce VSM injury. The model system allows precise control of the applied strain and strain rate and quantification of the injury severity in terms of membrane damage. The determination of the threshold criteria for cell injury will allow the angioplasty procedure to be modified, and possibly automated, to minimize VSM injury and avoid the restenosis response.
Dynamic Formation for the Mechanical Connection of Focal Adhesion Complexes to Study Localized Mechanisms of Angiogenesis Through Modeling With Cellular Automata
Authors: LeDuc Philip R. 
Published: November 2021

Abstract
The mechanical connection through the formation of focal adhesion complexes (FACs) is critical in cell growth and apoptosis. The FACs act between the cells and the extracellular matrix (ECM), which in turn influences angiogenesis, the growth of new capillary blood vessels [1]. These complexes form direct connections from ECM into the cell cytoskeleton through a series of protein binding events. This linkage is critical for mechanical force sensing and mechanotransduction signaling [2]. Here, the probabilistic modeling of this complex formation is undertaken to begin to uncover the effect of the spatial distribution and temporal effects on this dynamic process. In this, the rich dynamic process of the FACs formation through the binding events of integrin, paxillin, talin, and vinculin are examined. The FACs are mediated through the clustering of transmembrane integrins, which initiate the binding cascade. This interaction has been shown to be a critical event in the activation of the mechanochemical cascade and further mediates downstream signaling of protein tyrosine kinases including focal adhesion kinase [3].
Nuclear Membrane Dynamics of a Nuclear Pore Complex Structure
Authors: Pidaparti R. M. , Sarma P. A. , Sinha A. S. C. , Vemuri G. , Gacy A. M. 
Published: November 2021

Abstract
The nuclear pore complex (NPC) is an excellent example of a bio-molecular motor, since it operates primarily via energy dependent processes, and performs some of the most vital functions required for the survival of a cell. In the presence of appropriate chemical stimuli, the NPC apparently opens or closes, like a gating mechanism, and permits the flow of material in to and out of the nucleus. An NPC, with typical dimensions of 100–200 nm, is a megadalton (MDa) heteromultimeric protein complex, which spans the nuclear envelope and is postulated to possess a transporter-containing central cylindrical body embedded between cytoplasmic and nucleoplasmic rings as shown in Fig.1. A cell has many, presumably identical, NPCs, each of which participates in the import and export of nuclear material from within the nucleus [1–2]. Exactly how this transport occurs through the NPC is an open question, and a very important one, with profound implications for nanoscale devices for fluidic transport, genetic engineering and targeted drug delivery.
Micromechanics of Extracellular Matrix: Three-Dimensional Microstructure Under Load
Authors: Roeder Blayne A. , Kokini Klod , Sturgis Jennifer E. , Robinson J. Paul , Voytik-Harbin Sherry L. 
Published: November 2021

Abstract
The extracellular matrix (ECM) guides tissue form and function by communicating to cells both biochemical and mechanical information about the local micro-environment. It is well established that mechanical loads to tissues influence fundamental cellular processes including proliferation, migration, formation of adhesion complexes, and gene expression [1]. However, the pathway that transduces these forces from the tissue (macro) to the cellular (micro) level remains to be elucidated. In order to understand how cells interact mechanically with their surroundings, the three-dimensional (3D) micromechanical properties of the ECM must be understood. Advancements in the knowledge of ECM micro-behavior will be key to the development of future tissue engineering strategies.
Soft Gel Chromatography Column Analysis and Design for the Production of High Molecular Weight Blood Factors: Model Molecular Protein C
Authors: He Weiwei , Bruley Duane F. 
Published: November 2021

Abstract
Preparative chromatography involves column design from a biomechanical as well as from a biochemical perspective. Column collapse is a costly phenomena if expensive resins are used as the matrix material. This is particularly true for the soft gels that are useful for the separation of large water-soluble molecules, such as proteins. The model molecule for this research is human Protein C which is being separated from transgenic animal milk. Human Protein C is an important anticoagulant and antithrombotic in the human bloodstream [1].
Vibration of Elastic Continuum With Stochastically Varying Surface Roughness Carrying an Accelerating Oscillator
Authors: Schenk Christian A. , Bergman Lawrence A. 
Published: November 2021

Abstract
The problem of calculating the second moment properties of the response of a general class of non-conservative linear distributed parameter systems with stochastically varying surface roughness excited by a moving concentrated load is investigated. In particular, the method as presented in [1] is extended to the case of an arbitrarily varying oscillator speed. The resulting initial boundary value problem is transformed into the modal state space, where the second moment characteristics of the response are determined by direct integration using a Runge-Kutta method.
Dynamic Analysis of Semi-Active Tuned Vibration Absorbers Using Closed-Form Equivalent Models
Authors: Koo Jeong-Hoi , Ahmadian Mehdi 
Published: November 2021

Abstract
The main purpose of this study is to investigate dynamic characteristics of semi-active Tuned Vibration Absorbers (TVAs) using an adjustable damper, such as a Magneto-Rheological (MR) damper. Based on on-off and continuous control polices, closed-form groundhook equivalent models are developed for analytical studies of semi-active TVA models. In addition, the transmissibilities of groundhook equivalent models are compared with passive TVAs. The results indicate that semi-active TVAs, with off-state damping levels within a critical value, are capable of lowering the magnitude of resonant peaks without increasing vibration. In contrast, increasing damping in passive TVAs results in reducing the amplitude of resonant peaks at the expense of increasing vibrations at the tuned frequency. A parametric study of the groundhook TVAs shows that the effectiveness of semi-active TVAs increases with larger on-state damping, larger mass ratio, and smaller off-state damping.
Model Based Control of a Smart Vibrating Cantilever Beam
Authors: Scott Robin G. , Brown Michael D. , Manning Warren J. , Levesley Martin C. 
Published: November 2021

Abstract
This paper compares Generalised Minimum Variance and Pole-placement techniques for the control of a lightly damped cantilever beam smart structure. Saturation of the control signal can lead to limit cycles in Pole-placement control. Saturation compensation can remove these limit cycles, allowing disturbances of the beam to be rejected, but introduces a low amplitude, higher frequency vibration effect. Control sensitivity functions used to investigate these limit cycles show that certain Pole-placement controllers are sensitive to frequencies in the 50Hz range. The sensitivity of a Generalised minimum variance (GMV) controller is shown to be less than that of the Pole-placement controller. This GMV controller is applied to the vibration control of the smart beam. The controller weightings of the cost function limit excessive control signals. Previous work allows a plant model to be generated that produces results that closely match experimental data. Control results shows that the GMV technique is highly effective in reducing both the decay time and amplitude of vibration for free and forced vibrations respectively.
A Systematic Approach for Machining Process Improvement
Authors: Seth Brij B. , Hamidieh Youssef A. , Muniyappa Balachandra 
Published: November 2021

Abstract
Vibrations and other signals have been used in machine condition monitoring to improve equipment maintenance practices in high volume production environments. Typically, the signals are obtained with the equipment running at steady speeds under idle conditions. However, evaluation of the performance characteristics of the machining process under actual machining conditions can provide critical information for identifying shortcomings of the process, and/or opportunities for design modification in the process. A systematic approach incorporating vibration and dynamic stiffness measurements at critical locations in machining processes, along with the use of upfront design tools, has been presented to improve the performance reliability of machining processes. Application of this approach has resulted in the development of investment efficient machining processes that provide consistent quality performance on the plant floor.
Study of Automotive Hydrobushing in Off-Axis Vibration
Authors: Lu Min , Ari-Gur Judah , Garety John 
Published: November 2021

Abstract
A model was developed for the dynamic behavior of a misaligned hydrobushing, which is forced to oscillate in directions that are not aligned with the axis of the fluid chambers. It was found that the displacement of the fluid in the inertia track and of the equivalent piston peak at the fluid resonant frequency, but they decrease when the off-axis angle increases. Similarly, the fluid pressure difference between the chambers peaks at the fluid resonant frequency and it decreases when the off-axis angle increases. The dynamic stiffness and loss angle are functions of the off-axis angle and become less and less sensitive to the frequency when the off-axis angle increases. At high frequencies, the dynamic stiffness is the sum of the static stiffness and the equivalent volumetric stiffness. A comparison of the measured and calculated equivalent volumetric stiffness shows good correlation. But further work is needed to improve the accuracy of the dynamic stiffness and loss angle prediction.
The Generalized Shooting Arc-Length Method for Periodic Solutions and the Corresponding Periods of Nonlinear Dynamical Systems
Authors: Li Dexin , Xu Jianxue 
Published: November 2021

Abstract
In this paper, a generalized shooting/arc-length method for determining periodic orbit and its period of nonlinear dynamical system is presented. At first, by changing the time scale the period value of periodic orbit of the nonlinear system is drawn into the governing equation of this system. Then, by using the period value as a parameter, the shooting/arc-length procedure is taken for seeking such a periodic solution and its period simultaneously. The value of increment changed in iteration procedure is selected by using optimization method. The procedure involves the detennining of periodic orbit and its period value of the system. Thereby, the periodic orbit and period value of the system can be sought out rapidly and precisely. At last, the validity of such method is verified by determining the periodic orbit and period value for van der pol equation and nonlinear rotor-bear system.
Combination Resonance of a Magnet Over a High-TC Superconductor Excited Vertically
Authors: Sugiura Toshihiko , Kondo Masayuki 
Published: November 2021

Abstract
This research deals with nonlinear dynamics of a permanent magnet freely levitated above a high-Tc superconductor (HTSC) excited in the vertical direction. Magnetic force and torque can be evaluated analytically by the advanced mirror image method as nonlinear functions of both displacement and roll angle of the magnet. Equations of 3 d.o.f. motion show that the magnet has two oscillation modes due to linear coupling of the horizontal and roll motions. The both modes can be excited by nonlinear coupling with vertical motion when the superconductor is exited vertically in the neighborhood of the sum of the natural frequency of each mode. Frequency response of this combination resonance was numerically simulated. This resonance was also observed in experiments.
Nonlinear Vibration and Periodicity Analysis of Timoshenko Beams Under Harmonic Base Excitation
Authors: Jalili Nader , Esmailzadeh Ebrahim 
Published: November 2021

Abstract
The parametric response of a cantilever thick beam with a tip mass subjected to harmonic axial support motion is investigated. The governing non-linear equation of motion is derived for an arbitrary axial support motion. To formulate a simple, physically correct dynamic model for the stability and periodicity analyses, the governing equation is truncated to the first characteristic mode of vibration. Using Green’s function and Schauder’s fixed point theorem, the necessary and sufficient conditions for the existence of periodic oscillatory behavior of the beam are established. The influence of the harmonic base excitation parameters, i.e., the excitation amplitude and frequency, on the steady-state amplitude of vibration are determined. Depending on the values of the excitation amplitude and frequency in the stable and unstable regions, the solution exhibits many shapes besides the transition periodic shapes. Numerical results indicate that for a given beam under a known excitation, increasing the tip mass would usually reduce the stable periodic region. To show the effect of rotary inertia and shear deformation, the beam model is reduced to the Euler-Bernoulli and purely flexural beam theories, respectively. The results show that using purely flexural or even Euler-Bernoulli model rather than Timoshenko, would produce an incorrect periodic region.
Experiments on the Active Control of Circular Disk Vibration
Authors: Qiu J. B. , Huang X. Q. , Wang D. Q. 
Published: November 2021

Abstract
Circular disk is a basic mechanical element, which is used widely in industry such as turbine machine, circular saw, and computer memory. Considering the requirements for the actuator to control the transverse vibration of circular disk, the non-contact electromagnetic actuator which can produce large actuating force is used, and a whole set of control system that is composed of analog components is built. The good experimental results are obtained by using the control system to control the transverse vibration of circular disk.
Vibration of Free-Free Two Member Open Frames With End and Elbow Masses
Authors: Heppler G. R. , Oguamanam D. C. D. , Hansen J. S. 
Published: November 2021

Abstract
The vibration of an, in general, unrestrained two member open frame structure undergoing both in- and out-of-plane motion is examined. The frames are modeled using the Euler-Bernoulli beam theory and are further generalized by permitting an arbitrary angle between the beams and the attachment of point masses at the ends and joint (elbow) of the beams. The equations of motion are derived using Hamilton’s principle and the orthogonality conditions are presented. It is shown that the in-plane and out-of-plane motions can be decoupled by including the axial deformation components in the assumed displacement fields. The natural frequencies of the system and the contribution of each member into the system potential energy are examined via numerical examples.
The Bifurcation Behaviors for a 5D Magnetic Levitation Control System
Authors: Yao Hong , Xu Jian-Xue 
Published: November 2021

Abstract
This study concerns the local and global bifurcation behaviors for the 5D magnetic levitation flex-rotator control system. A five dimension dynamic model of the system is constructed and appropriate equations of the nonlinear control system are developed. The co-dimension two local bifurcation is discussed. An analytical method was formulated and used to directly yield two dimension normal forms, and universal unfolding for the case with the non-semisimple double zero eigenvalue about the system; by Melnikov method, global homoclinic bifurcation behaviors are discussed. The conditions of bifurcation for various parameters, bifurcation curve, parameters plane, are obtained. A safe domain for selection of the parameters of the system is given. Finally, the theoretic analysis is proved by simulating for a 5D control system. Hopefully, the breath of the application will indicate the potential of the theoretic analysis.
Robust Stability and Dynamic Analysis of a Special Type of Floating Offshore Structure
Authors: Esmailzadeh E. , Goodarzi A. 
Published: November 2021

Abstract
A comprehensive dynamic model of a catenary anchor leg mooring system has been developed and the governing equations of notion were derived. The equations of motion are found to be nonlinear parametric ordinary differential ones of the order two. The necessary and sufficient conditions, for the existence of a stable periodic response of this system, were found using the Green’s function and Schauder’s fixed-point theorem. The validity of the assumptions has been fully demonstrated with a few case studies. Results obtained from the dynamic modeling reiterate the presence of inherently nonlinear and time-varying characteristics of the system and hence a stability condition in terms of the physical and environment parameters of the system must be sought.
On the Suppression of Flow-Induced Vibration With a Simple Control Algorithm
Authors: Carbonell Pablo , Wang Xiaodong , Jiang Zhong-Ping 
Published: November 2021

Abstract
We present a study on the suppression of flow-induced vibration using a simple control algorithm with an assumption that the disturbance as well as the system parameters are bounded variables. By introducing three different control signals, we explore three schemes, namely, robust control, sliding mode, and adaptive control. The control schemes are implemented numerically with a few illustrative examples, which includes a bounded chaotic system. It is demonstrated that all three schemes can be effectively used for fluid-structure interaction systems. In addition, with these numerical examples, we also illustrate various advantages and disadvantages of different control schemes. In general, robust control and adaptive control schemes are (globally) ultimately uniformly bounded, whereas sliding mode scheme is (globally) asymptotically stable. Thus, as we further reduce the integration time step, the residual of robust control and adaptive control schemes will approach to a bounded (finite) asymptotic function, and the residual of sliding mode scheme will approach to zero. Furthermore, due to self-tuning, the gain of adaptive control scheme is relatively small, yet, the computation cost is higher because of the excessively small time step requirement for the numerical integration. With respect to sliding mode scheme, the control signal is discontinuous due to the sign function and consequently, the practical implementation has fast switching fluctuations (chattering).
Vibration Analysis of Multifunctional Satellite Structure
Authors: Nayeb-Hashemi H. , Vaziri A. 
Published: November 2021

Abstract
Natural frequencies and damping ratios of doubly clamped and cantilever alviminum pipes filled with high pressure gas (Argon or, Xenon fuel) or high pressure liquid (Water) were measured using shaker and hammer test techniques. The results show that natural frequencies and damping are a little sensitive to the pipe internal pressure. The damping ratios were slightly affected by the pipe filler material. However, the natural frequencies of the pipe filled with water was lower compared to those filled with Argon and Xenon fuel. The damping ratios measured using a shaker were almost two orders of magnitude lower than those measured using hammer tests. This could be due to the extra damping induced to the system from the magnetic field of the shaker.