bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Smart Composite Plates With Segmented Active Constrained Layer Damping
Authors: Beri Rajan , Chattopadhyay Aditi 
Published: November 2021

Abstract
A rigorous multi-objective optimization procedure is developed to address the integrated structures/controls design of composite plates with surface bonded segmented active constrained layer (ACL) damping treatments. The Kresselmeier-Steinhauser function approach is used to formulate this multidisciplinary problem. The goal is to control vibration without incorporating a weight penalty. Objective functions and constraints include damping ratios, structural weight and natural frequencies. Design variables include the ply stacking sequence, dimensions and placement of segmented ACLs. The control systems design is performed using two separate optimal control systems based on linear quadratic regulator (LQR) theory and linear quadratic gaussian (LQG) theory.
The optimal designs show improved plate vibratory characteristics and reduced structural weight. In addition, the studies show that including a greater number of segmented ACL damping treatments of relatively smaller size provides optimum designs with better overall vibration suppression characteristics and lower structural weight, in comparison to using fewer ACL treatments of larger size. The choice of control system employed does not produce significant changes in the results of the optimization studies.
The impact of varying the properties and locations of the segmented ACLs, on the vibration suppression characteristics of the plate, is larger compared to the effect of varying ply stacking sequence alone. Composite tailoring, however, provides a viable means of improving vibration control of composite plates with segmented ACL damping, without altering the ACL configurations or incorporating a weight penalty. Results obtained indicate the importance of incorporating both structural and control objectives, simultaneously rather than sequentially, in the design problem to obtain meaningful design trends in such multidisciplinary problems.
Assessment of Solutions to Vibration Problems Involving Piecewise Constant Exertions
Authors: Dai L. 
Published: November 2021

Abstract
Direct analytical and numerical solutions are constructed for linear and nonlinear vibration problems involving piecewise constant exertions. Existence and uniqueness of the solutions and the truncation errors of the numerical calculations are also analysed. With the employment of a piecewise constant argument, vibration systems with piecewise constant exertions are connected with the corresponding systems with continuous exertions.
Radar Target Identification With JEM Effect
Authors: Yao Xiaodong , Jing Zhongliang 
Published: November 2021

Abstract
The jet engine modulation (JEM) effect is given. The backscattered characteristic of the electro-magnetic wave of airplane is analyzed. The spectral analysis technique based on cumulant is used to process the practical dynamic data by low-resolution radar, and the JEM spectral line is obtained. The implication for JEM target identification system is discussed based on the fuzzy neural network (FNN) and the short time Fourier transformation (STFT).
Differential Quadrature Element Method for the Analysis of Vibration of Frame Structures Having Nonprismatic Members Considering Warping Torsion
Authors: Chen Chang-New 
Published: November 2021

Abstract
The differential quadrature element method (DQEM) and the extended differential quadrature (EDQ) have been proposed by the author. The EDQ is used to the DQEM vibration analysis frame structures. The element can be a nonprismatic beam considering the warping due to torsion. The EDQ technique is used to discretize the element-based differential eigenvalue equations, the transition conditions at joints and the boundary conditions on domain boundaries. An overall discrete eigenvalue system can be obtained by assembling all of the discretized equations. A numerically rigorous solution can be obtained by solving the overall discrete eigenvalue system. Mathematical formulations for the EDQ-based DQEM vibration analysis of nonprismatic structures considering the effect of warping torsion are carried out. By using this DQEM model, accurate results of frame problems can efficiently be obtained.
Static Deflection and Free Vibration of Nonprismatic Beam Structures Solved by DQEM Using EDQ
Authors: Chen Chang-New 
Published: November 2021

Abstract
The development of (DQEM) analysis models of static deformation and free vibration problems of generic non-prismatic beam structures was carried out. The DQEM uses the extended differential quadrature (EDQ) to discretize the buckling equilibrium equation defined on each element, the transition conditions defined on the inter-element boundary of two adjacent elements and the boundary conditions of the beam. Numerical results solved by the developed numerical algorithm are presented. They prove that the DQEM efficient.
Measurement of the Optical Properties of Muscle Tissue In Vivo
Authors: Kopsombut P. L. , Willis D. , Schen A. E. , Xu L. X. , Xu X. 
Published: November 2021

Abstract
Along with rapid development of diagnostic and therapeutic applications of lasers in medicine, optical properties of various biological tissues have been extensively studied [1]. Most of the studies were performed in vitro owing to the complexity involved in in vivo measurement. To date, it is well understood that living tissue is an absorbing and scattering heterogeneous medium because of its complex structures including blood network. The transport theory cannot be readily used due to the heterogeneity and the absence of the optical properties of living tissues [2]. In this research, we have developed a procedure for measuring the total attenuation coefficient (μ1) of the exteriorized rat 2-D spinotrapezius muscle in the wavelength ranged from 480–560 nm using the collimated light from a Nitrogen-pumped dye laser and a high-sensitivity CCD camera.
Effect of Cell Density on Post-Thaw Viability in Cryopreserved Artificial Tissue
Authors: Ujihira Masanobu , Matsumura Yumi , Kuroda Chinatsu , Okaniwa Koji , Mabuchi Kiyoshi 
Published: November 2021

Abstract
The effect of cell density on the post-thaw viability of cells in cryopreserved artificial tissue was studied. Human fibroblasts were three-dimensionally cultured for 2 days in a collagen sponge (ϕ20×1mm) as an extracellular matrix to imitate biological tissue (artificial tissue). Different cell densities for the artificial tissue were used, from 104 to 107 cells/cm3. Four artificial tissues were first stacked in a test chamber, then frozen at a slow or fast cooling rate (either 1 or 50°C/min) in a solution of Dulbecco’s Modified Eagle Medium, 20% Fetal Bovine Serum, and 10% dimethylsulfoxide, then kept frozen at −196°C for 2 hours, and finally thawed. The collagen matrix of the artificial tissue was dissolved using collagenase. Post-thaw viability of fibroblasts was evaluated by using a trypan blue exclusion assay. The experiments were prepared, and then the latent heat of artificial tissue (3.5×3.5×1mm) during the freezing process was measured by using a differential scanning calorimeter. Results show that with increasing cell density, the post-thaw viability decreased, whereas the latent heat was almost independent of cell density. With increasing cell density at the slow cooling rate, the degree of supercooling of the intracellular solution increased with decreasing temperature, possibly leading to intracellular freezing. Moreover, when the cell density was high, cell-to-cell contact or an obstruction to dehydration seemed to induce intracellular freezing. Therefore, the post-thaw viability seems to decrease as the number of cells exhibiting intracellular freezing increased.
Red Blood Cell Distribution Effect on Lung Diffusing Capacity: A Macroscopic Analysis
Authors: Kulish Vladimir V. , Lage José L. , Hsia Connie C. W. , Johnson Robert L. 
Published: November 2021

Abstract
A novel mathematical model derived from fundamental engineering principles for simulating the spatial and temporal gas diffusion process within the alveolar region of the lung was presented recently by Koulich et al. [1]. The model depends on a physical property of the alveolar region termed effective diffusivity, function of the diffusivity, solubility, and interface geometry of each alveolar constituent. Unfortunately, the direct determination of the effective diffusivity of the alveolar region is impractical because of the difficulty in describing the internal geometry of each alveolar constituent. However, the transient solution of the macroscopic model can be used in conjunction with the lung diffusing capacity (measured in laboratory via the single-breath technique) to determine the effective diffusivity of the alveolar region. With the effective diffusivity known, the three-dimensional effects of red blood cell distribution on the lung diffusing capacity can be predicted via numerical simulations. The results, obtained for normal (random), uniform, center-cluster, corner-cluster, and several chain-like distributions, unveil a strong relationship between the type of cell distribution and the lung diffusing capacity.
Thermal Therapy of Toe Nail Fungus
Authors: Chato John C. 
Published: November 2021

Abstract
A thermal treatment of toe nail fungus has been developed. The success of this procedure depends on the apparent thermal sensitivity of the fungus as well as on the transient thermal gradient developed in the toe nail, in the underlying fungus, and in the tissue underneath it while the outer surface of the toe nail is heated with a thin stream of 50 °C water. Each treatment, which is to be repeated several times in a predetermined fashion, lasts only a few seconds. The only danger is that if the treatment time is extended, the tissue under the toenail may suffer burn damage.
Development of a Novel In Vivo Assay for Assessment of Tissue Viability: A Cryosurgery Application
Authors: Elliott G. D. , Fron D. , McGrath J. J. , Seip C. , Crockett-Torabi E. 
Published: November 2021

Abstract
Our recent success with applying a novel Green Fluorescent Protein (GFP) viability assay to isolated cells after freezing has suggested possible utility for assessing viability of cells within tissues, both in situ, and intravitally. The current work seeks to establish that following freezing, changes in the fluorescent intensity of tumors grown from GFP-transfected cells will correlate with tissue damage as assessed by histological methods, thereby evaluating the use of a transfection-based assay for in vivo purposes. GFP-fluorescing R3230AC tumors were grown inside implanted dorsal skin flap chambers, and treated cryosurgically after 6-9 days of growth. Fluorescent images of the tumors were acquired at the center of the viewing area before, during, and for 6 hours following freezing. Following the observation period the animal was immediately euthanized and the tissue within the chamber was fixed in formalin and stained for histological analysis. The results of intravital microscopy in a centrally located test area revealed a large reduction in fluorescent intensity within the tumor tissue immediately following the final freeze-thaw cycle, with little subsequent change during the subsequent 6 hour observation period. In H&E section significant damage was observed in the central test areas. Taken together, this evidence suggests that the GFP assay is not limited to isolated cells, but can serve as the basis for intravital assessment of viability.
Stress Concentration in a Connectorized Optical Fiber
Authors: Malluck John F. , King Wilton W. 
Published: November 2021

Abstract
For the most part, analyses of fiber fractures in connectors have been in the form of postmortem fractography. Typically in these works, characteristics of prefracture stress states have been inferred from fracture surfaces, and plausible qualitative explanations have been advanced about the likely structural mechanics and circumstances leading to fractures. The authors and their colleagues have undertaken a number of investigations of relevant structural mechanics. These have served the useful purpose of elucidating gross mechanisms, but the influence of the fine details of stress distributions have been missing.
Considered here is a cylindrical-ferrule connector for which, typically, the ferrule is ceramic with an outside diameter of 2.5mm or 1.25mm. The fiber to be terminated is bonded into a small-bore axial hole (capillary) in the ferrule by an epoxy or similar adhesive. In addition, fiber insertion into the capillary is facilitated by ferrule designs that provide a conical entrance cavity leading to the capillary. A very high percentage of fiber failures, both in the laboratory and the field, occur at the transition region between the fiber and the capillary; so analysis is focused on that region.
The stress distribution within an optical fiber adhesively bonded to a ceramic ferrule is determined by the finite element method for uniform remote tension acting on the fiber. An axisymmetric model is constructed to represent the fiber, epoxy, and geometry of the ferrule under this particular loading condition. The resulting stress distribution is determined within the fiber and the epoxy layer using the ANSYS finite element code. Analysis of the stress distribution reveals the presence of two stress concentrations located at the surface of the fiber as the fiber enters the ferrule. One stress concentration occurs as the fiber encounters the epoxy within the conical cavity. The second stress concentration occurs as the fiber enters the capillary. These stress concentrations when combined with surface damage (flaws) may lead to fiber breakage. Further analysis reveals that a smooth fillet transition between entrance and capillary could significantly reduce the stress concentration at the capillary entrance. Finally, a simulation of epoxy debonding within the entrance cone reveals an increase of stress concentration at the capillary entrance.
Effect of Moisture on the Interfacial Adhesion of the Underfill/Solder Mask Interface
Authors: Ferguson Timothy P. , Qu Jianmin 
Published: November 2021

Abstract
A primary concern in microelectronic packaging is the role of moisture induced failure mechanisms. Moisture is a multidimensional concern in packaging, having an adverse effect on package reliability by introducing corrosion, development of hygro-stresses, and deterioration of polymer interfaces within the package. In this paper the effect of moisture on the interfacial adhesion of two no flow underfill materials with a commercially available soldermask coated FR-4 board is experimentally determined. Bilayer specimens with prefabricated interface cracks are used in a four point bending test to quantify the interfacial fracture toughness. Two groups of test specimens of varying underfill thickness were constructed. The first group was fully dried while the other was moisture preconditioned at 85°C/85%RH for 725 hours. The results of this study show that the interfacial toughness is significantly affected by the presence of moisture.
Bayesian Belief Network Modeling and Diagnosis of Xerographic Systems
Authors: Zhong Chunhui , Li Perry Y. 
Published: November 2021

Abstract
In this paper, a Bayesian Belief Network (BBN) approach to the modeling and diagnosis of xerographic printing systems is proposed. First, a continuous BBN model based on physics of the printing process and field data is developed. The model captures the causal relationships between the various physical variables in the system using conditional probability distributions. Next, the continuous BBN is discretized based on the principle of maximum entropy so that it can be implemented on commercially available software, Hugin. The resulting BBN can be used for the prediction of print quality behaviors, as well as for inference and fault diagnosis. Examples of network deduction and inference are presented to illustrate the usefulness of the BBN model.
Pulse Width Modulation Control of Robots With Structural Flexibility
Authors: Rathbun David B. , Berg Martin C. 
Published: November 2021

Abstract
The accuracy to which the end effector of a robotic manipulator can be positioned is often limited by structural flexibilities and nonlinear friction. This paper develops a control design methodology for such systems based on pulse width modulation. This methodology achieves comparatively very accurate point-to-point position control and does not require a high fidelity model of either the robot dynamics or the friction behavior. Conditions under which the controller must directly treat plant structural flexibility are presented. Conditions on parameters of the closed loop system that guarantee stability and a well defined level of performance are given. The methodology is demonstrated by application to a six axis industrial robot.
On the Discontinuity of the Costates for Optimal Control Problems With Coulomb Friction
Authors: Driessen Brian J. , Sadegh Nader 
Published: November 2021

Abstract
This work points out that the costates are actually discontinuous functions of time for optimal control problems with Coulomb friction. In particular these discontinuities occur at the time points where the velocity of the system changes sign. To our knowledge, this has not been noted before. This phenomenon is demonstrated on a minimum-time problem with Coulomb friction and the consistency of discontinuous costates and switching functions with respect to the input switches is shown.
Design of Adaptive Supervisors for Discrete Event Systems via Learning
Authors: Gordon Diana , Kiriakidis Kiriakos 
Published: November 2021

Abstract
In many practical applications, modeling using event-driven dynamics leads to interconnected discrete event systems. Often, these tend to be large-scale event-varying structures, which need to possess certain event-invariant properties. Although supervisory control theory offers some methods for the synthesis of such discrete event systems, adaptive supervision is, by and large, an open problem. This paper proposes an approach to the design of adaptive supervisors based on a systematic revision of the desirable language, via a learning mechanism, so that the system’s properties are safe.
Yaw Dynamic Modeling for Improved High Speed Control of a Farm Tractor
Authors: Bevly David M. , Gerdes J. Christian , Parkinson Bradford W. 
Published: November 2021

Abstract
This paper presents the system identification of a farm tractor in order to improve automatic control at higher speeds and understand controller limitations from neglecting the yaw dynamics. Yaw dynamic models are developed for multiple speeds to show the effect of velocity on the model. The identified modeled yaw dynamics do not resemble any traditional analytical models. Additionally, the effect of velocity on the closed loop bandwidth of the controller for a given set of LQR controller weights is presented. Results are given that validate that as the closed loop bandwidth of LQR control weights approaches the regime of the unmodelled yaw dynamics, the controller can go unstable. Finally results show an improvement of the lateral tracking error (with a decrease in control effort) using the system identification model.
Nonlinear Air-to-Fuel Ratio and Engine Speed Control for Spark Ignition Engines
Authors: Wagner J. R. , Dawson D. M. , Liu Z. 
Published: November 2021

Abstract
The wide-range of operating conditions, inherent induction process nonlinearities, and gradual component degradations due to aging, have prompted research into model-based engine control algorithms. Consequentially, a variety of nonlinear and intelligent algorithms have been proposed and experimentally studied. Recent attention has focused on the simultaneous regulation of the air-to-fuel ratio and engine speed using a sliding mode control strategy. In this paper, a nonlinear model-based backstepping control strategy will be proposed for simultaneous air-to-fuel ratio control and speed tracking in passenger/light-duty automobile engines. For comparison purposes, a multi-surface sliding mode controller and an integrated speed-density air-to-fuel controller with attached engine speed regulation will be implemented. Representative numerical results will be presented and discussed.
An Analysis of Circular Bolted Flanged Joints on Solid Round Bars Subjected to External Bending Moments
Authors: Sawa Toshiyuki , Morohoshi Tsuneshi , Shimizu Akihiro 
Published: November 2021

Abstract
In designing bolted joints, it is important to know the contact stress distribution which governs the clamping effect or the sealing performance and to estimate the load factor (the ratio of an increment in axial bolt force to an external load) from bolt design standpoint. The clamping force by bolts and the external bending moment are axi-asymmetrical loads and not many investigations have seen reported which treat axi-asymmetrical. In this paper, the clamping effect, and the load factor for the case of solid round bars with circular flanges, subjected to external bending moments, are analyzed as an axi-asymmetrical problem using the three-dimensional theory of elasticity. Experiments were carried out concerning the contact stress distribution, and the load factor for the external bending moment (a relationship between an increment in axial bolt force, and external bending moment). The analytical results were in fairly good agreement with the experimental ones.
Analysis of the Tightening Process of Bolted Joint With a Tensioner: Effects of Interface Stiffness
Authors: Fukuoka Toshimichi 
Published: November 2021

Abstract
Hydraulic tensioners are widely used in tightening important structural members such as large-sized diesel engines and pressure vessels. The ratio of desired clamping force to initial tension, which is termed effective tensile coefficient, is the most important factor to be predicted in the actual operation for given joint configurations. In this paper, an elementary approach to estimate this coefficient, taking the effects of interface stiffness into account, is proposed using spring elements. The influences of interface stiffness at four contact surfaces on the coefficient are discussed, and it is shown that interface stiffness of pressure flank of threads and bearing surface of nut has dominant effects on the coefficient.
Preparation of Injectable Human Tissue Matrix
Authors: DeVore Dale P. 
Published: November 2021

Abstract
Autogenous tissue has always been the best material for implantation. When available and practical, autogenous tissue preparations are inherently safe with no potential for rejection, allergic or immunogenic reactions. However it is rare that such tissue is readily available. Thus, allograft tissues have been the next best choice for implantation to repair or replace damaged, diseased or inadequate tissues. A recent survey from the American Association of Tissue Banks (AATB) reported that more than 400,000 allograft tissues were transplanted in 1996. These tissues included bone, tendon, skin, fascia, and dura, pericardium and cardiovascular. Tissues are recovered from organ and tissue donors and donation is strictly regulated by the Food and Drug Administration (FDA) and AATB to ensure the safety of such transplants. In the last decade there have been no confirmed reports of AIDS transmission from allograft implants.
Dynamic Compression Stimulates the Development of Equilibrium Aggregate Modulus in Tissue Engineered Cartilage Constructs
Authors: Mauck Robert L. , Palmer Glyn D. , Wang Christopher C.-B. , Soltz Michael A. , Valhmu Wilmot B. , Ateshian Gerard A. , Hung Clark T. 
Published: November 2021

Abstract
A major challenge facing the tissue engineering of articular cartilage is the ability to grow tissue constructs that have the proper mechanical and biochemical properties that permit cartilage to serve its load-bearing function. This study tested the hypothesis that physiologic deformational loading enhances the formation of functional material properties in cell-seeded agarose constructs (versus free-swelling constructs).