bluuebunny/crossref_metadata_2025_split huggingface dataset:
Load-Displacement Characteristics of an Implanted Nuclear Pouch in the Lumbar Spine
Authors: Dooris Andrew P. , Grosland Nicole M. , Goel Vijay K. , Drake John S. , Ahern James W. , Roche Karen M. , Wolfe Steven J. 
Published: December 2021

Abstract
Fusion of the spinal segments is typically done to prevent or correct deformity, stabilize the spine after trauma or pathologic destruction, or eliminate painful movement of the spinal segments. Spinal interbody arthrodesis typically requires considerable patient exposure, necessary for discectomy and graft implantation, and resultant morbidity. Some researchers suggest nuclear replacements as active joint mobilizers, while others suggest full disc replacements, and although some biomechanical consideration has been given, results are unclear. We consider here a device which proposes to reduce surgical morbidity while promoting stability by fusion. The device investigated here is a bone-chip pouch, which fills the nuclear space. We present here initial findings of this device in lumbar cadaveric specimens.
Knee Joint Response to Compressive Loading and Ligament Injury
Authors: Lee Jordan , Fronczak Frank 
Published: December 2021

Abstract
The knee joint is a six degree-of-freedom joint which has a complex response to loading. The joint has a characteristic behavior for particular ligament injuries such as anterior cruciate ligament failure. The response of the joint to a combination of compressive loading and secondary loadings was examined in this study. The secondary loadings were: an anterior force, a valgus moment, an internal torque, or an external torque.
A goat model was used with 17 specimens testing different ligament injuries in vitro, specifically stretched or severed anterior cruciate ligaments (ACL) and lateral collateral ligaments (LCL). The femur was held fixed and the tibia loaded in a specially designed apparatus, allowing complete six degree-of-freedom joint motion. The motion of the tibia with respect to the femur was recorded using a coordinate measuring machine. The knee joint demonstrated sensitivity to ACL injuries but not to LCL injuries for the loadings examined. The response to ACL injuries was more highly dependant on the compressive load than the secondary loadings for all tests.
A Fibril Reinforced Poroelastic Model of Articular Cartilage Including Depth Dependent Material Properties
Authors: Li L. P. , Buschmann M. D. , Shirazi-Adl A. 
Published: December 2021

Abstract
Articular cartilage is a highly nonhomogeneous, anisotropic and multiphase biomaterial consisting of mainly collagen fibrils, proteoglycans and water. Noncalcified cartilage is morphologically divided into three zones along the depth, i.e. superficial, transitional and radial zones. The thickness, density and alignment of collagen fibrils vary from the superficial zone, where fibrils are oriented parallel to the articular surface, to the radial zone where fibrils are perpendicular to the boundary between bone, and cartilage. The concentration of proteoglycans increases with the depth from the cartilage surface. These regional differences have significant implications to the mechanical function of joints, which is to be explored theoretically in the present work by considering inhomogeneity along the cartilage depth. A nonlinear fibril reinforced poroelastic model is employed as per Li et al. (1999) in which the collagen fibrils were modeled as a distinct constituent whose tensile stiffness was taken to be very high and be strain dependent but whose compressive stiffness was neglected.
Airbag Inflators
Authors: Broadhead William G. , Zinke D. Theodore 
Published: December 2021

Abstract
The design of an airbag restraint system presents a classic engineering challenge. There are numerous design parameters that need to be optimized to cover the wide range of occupant sizes, occupant positions and vehicle collision modes. Some of the major parameters that affect airbag performance include, the airbag inflator characteristics, airbag size and shape, airbag vent size, steering column collapse characteristics, airbag cover characteristics, airbag fold pattern, knee bolsters, seat, seat belt characteristics, and vehicle crush characteristics. Optimization of these parameters can involve extremely costly programs of sled tests and full scale vehicle crash tests. Federal Motor Vehicle Safety Standards (FMVSS) with regard to airbag design are not specific and allow flexibility in component characteristics.
One design strategy, which is simplistic and inexpensive, is to utilize a very fast, high output gas generator (inflator). This ensures that the bag will begin restraining the occupant soon after deployment and can make up for deficiencies in other components such as inadequate steering column collapse or an unusually stiff vehicle crush characteristic. The use of such inflators generally works well for properly positioned occupants in moderate to high-speed frontal collisions by taking advantage of the principle of ridedown. When an airbag quickly fills the gap between the occupant and the instrument panel or steering wheel it links him to the vehicle such that he utilizes the vehicle’s front-end crush to help dissipate his energy, thus reducing the restraint forces. Unfortunately, powerful airbag systems can be injurious to anyone in the path of the deploying airbag. This hazard is present for short statured individuals, out of position children or any occupant in a collision that results in extra ordinary crash sensing time. Currently, the National Highway Traffic Safety Administration (NHTSA) is proposing to rewrite FMVSS 208 to help reduce such hazards.
An Analytical Investigation of Whiplash Injury Risk Related to Head Restraint Position
Authors: Kleinberger Michael , Sun Emily , Saunders James , Zhou Zaifei 
Published: December 2021

Abstract
Although no consensus currently exists on the mechanisms and tolerances of whiplash injuries, it is generally accepted that head restraint position plays an important role in determining injury risk. This study explores the effects of head restraint position on whiplash injury risk by analyzing a series of rear impact simulations. Head restraint height and backset are varied over a wide range of values and a number of engineering parameters believed to be related to whiplash injury risk are examined. Results indicate that relative motion between the head and torso is strongly related to head restraint position and relative stiffness of the head restraint and seat back. Whiplash injury risk is believed to be related to this relative motion.
Efficient Computation of Strain Energy Release Rate in Crack Growth Simulation
Authors: Chen D. J. 
Published: December 2021

Abstract
This paper utilizes an automated process to simplify the calculation of the strain energy release rate (SERR) during the crack propagation. The convergence of a finite element solution is achieved by adaptive re-meshing scheme with an error estimator of the linear strain triangular (LST) elements. As the desired mesh density is achieved, computation of the SERR using virtual crack closure technique (VCCT) can be obtained by using the static condensation scheme without re-analyzing the finite element models. Thus, the amount of computational and modeling time can be significantly reduced in the analysis of the crack propagation.
Influence of Fiber Orientation on Interlaminar Fracture Toughness of Composites
Authors: Yang Z. , Sun C. T. 
Published: December 2021

Abstract
In this paper, an experimental investigation and a finite element analysis on interlaminar fracture behavior and fracture toughness of multidirectional composite laminates are presented using end-notch flexure specimens. The (0 / θ) interfaces are considered. The fracture toughness of the interfaces is obtained from the experimental records of load and displacement histories, which is then calibrated by a finite element analysis based on the pseudo three-dimensional assumption. The fracture modes are separated and represented by fracture mode phase angles. Finally, the interlaminar fracture toughness and fracture mode mixities as functions of fiber orientation θ are established.
Machining Performance of PM Material Containing MnX Additives
Authors: Barnes S. , Nash M. J. , Lim M. H. 
Published: December 2021

Abstract
Improvements in the machining performance of ferrous powder metallurgy (PM) materials has recently been reported by one of the main manufacturers of metal powders. This improvement in machinability reportedly being achieved by the addition of a new free-machining additive which is marketed under the trade name of “MnX”. The work reported here, investigated this claim by comparing the performance of three PM materials with the same basic composition but different free-machining additives. The first material contained no free-machining additive, the second, contained the conventional manganese sulphide (MnS) additive and the third contained the new MnX additive. A turning operation was used to compare the performance of the three materials at cutting speeds in the range of 100–250 m/min using titanium nitride (TiN) coated UE6005 carbide inserts. The relative performance of the three materials was compared by measuring cutting forces, tool wear and the surface finish produced on the workpiece. It was found that at all cutting speeds investigated, the material containing MnX gave a superior performance. However, at higher cutting speeds the superiority of the material containing MnX was much more significant. In contrast, at the lowest cutting speed of 100 m/min, it was found that although the material containing MnX continued to exhibit the best performance, the differences between the three materials were substantially reduced and the material containing no free machining additive actually generated slightly less wear than the material containing MnS. The results therefore confirm that the new MnX additive is superior to the conventional MnS additive. However, this work has also demonstrated that relatively high cutting speeds are needed in order to obtain optimum benefits from the new additive.
Modeling and Compensation of Hysteresis in Piezoceramic Transducers for Vibration Control
Authors: Lee Soon-Hong , Royston Thomas J. , Friedman Gary 
Published: December 2021

Abstract
Hysteretic behavior in piezoceramic transducers is investigated theoretically and experimentally. The applicability of the rate-independent generalized Maxwell resistive capacitor (MRC) hysteresis model is established. Methods for MRC and inverse MRC online model identification are developed by first establishing that the MRC and its inverse are the same particular cases of the classical Preisach hysteresis model. This enables use of the extensive mathematical framework that has been developed for Preisach models. A method of incorporating the MRC model in a feedforward control scheme for hysteresis compensation is also presented. Experimental studies on a 1-3 piezoceramic composite support the theoretical developments and their applicability to piezoceramics.
Modeling and Optimization Issues Concerning a Circular Piezoelectric Actuator Design
Authors: Coorpender Steven J. , Finkel Daniel , Kyzar Jennifer , Sims Robert , Smirnova Alexandra B. , Tawhid Mohamed , Bouton Chad E. , Smith Ralph C. 
Published: December 2021

Abstract
An electromechanical model for a circular piezoelectric actuator is developed. A critical challenge in certain applications employing piezoceramic actuators is to maximize the displacement provided by the actuator while minimizing it power consumption. This problem is addressed here by developing an electromechanical model which can be used to optimize the volume displacement to admittance ratio for various circular actuator designs. The model includes multiple layers with independent radii which can be varied to optimize performance. The piezoceramic, bonding, plating, and mounting materials can be varied to accommodate various design criteria. An advantage of the model lies in the property that for a variety of material configurations, analytic solutions can be obtained. Numerical examples demonstrating the properties of the model are presented.
A Discrete Cell Model for Shape Control of Precision Membrane Antennae and Reflectors
Authors: Kalanovic V. D. , Padmanabhan K. , Jenkins C. H. 
Published: December 2021

Abstract
The potential for placing large precision reflectors in space is currently being investigated through the use of inflatable membrane structures. Their capacity for reducing launch mass and stowed volume is being exploited. However, on-orbit performance will require an understanding of the various influences on the deployment, inflation, and service of the membrane, and the associated effects on reflector surface precision.
Nonlinear controllers developed to improve performance of such systems are often dependent on state estimation and parameter identification procedures. The existence of these procedures, within the control strategy, increases the size of the algorithms, limiting the system performance in real-time. The research presented has as a main objective to create an intelligent controller, based on feedback error learning, which is capable of extracting performance information from precision large membrane deployables, and subsequently using this information to achieve maximum surface precision.
This paper presents a method to spatially discretize a doubly-curved membrane model into N = m × n spring-mass-damper cells. A recursive algorithm is developed and used in a simulator to predict the surface profile of the membrane. Each cell is connected to a feedback error learning controller in order to extract local state estimations. Simulation results are then compared to finite element predictions. The discrete cell model is shown to be simple enough for real-time control strategies, and potential methods for sensing/actuating to close the loop are discussed.
Development of a Test Bed for Evaluating Electron Gun Shape Correction of Distributed Structures
Authors: Martin Jeffrey W. , Main John A. , Nelson George C. 
Published: December 2021

Abstract
Electron gun control of distributed structures is an emerging technology that needs to be further characterized. Due to the experimental demands of this technique a unique testing apparatus must be developed. This equipment must meet the demands of high precision and high range measurement for use in “real-time” closed loop control applications. This system is further complicated in that these measurements must be done remotely, external to the bulky experimental apparatus. The system and issues concerning its use are discussed.
Active and Passive Vibration Control of Landing Gear Components
Authors: Kwak Seung-Keon , Washington Gregory , Yedavalli Rama K. 
Published: December 2021

Abstract
In this paper, we address a way to absorb the vibrations of large scaled heavy aircraft structures such as landing gear components, using the combination of active and passive controls. A steel tube, which is equivalent to Boeing 747 landing gear break rod, is selected as a test bed. The expected goal of this study is to dissipate the fundamental mode of the tube. A Beam type dynamic absorber and a constrained layer damping method are used for passive vibration controls. Both Matlab simulations and experimental results are provided for the dynamic absorber case. A fuzzy logic based controller with an acceleration measurement using piezoelectric actuators (PZT) is implemented in dSPACE for the active vibration control of the system. The integrated controller with passive and active components absorb the fundamental mode of the system according to the experimental results.
Structural Health Monitoring Applications Using Piezo-Dielectric Effects
Authors: Vipperman Jeffrey S. 
Published: December 2021

Abstract
A new method of sensing structural integrity using piezoceramic transducers is presented. Capacitance values of piezoceramic patches are dependent upon the prescribed mechanical boundary conditions. This dependence can be exploited to monitor the rudimentary health of a structure by monitoring the capacitance of an attached piezoceramic patch. An adaptive piezoelectric sensoriactuator is used because of its inherent ability to monitor the capacitance of piezoelectric transducers in real-time. A simple experiment is performed where the device is used to successfully detect a change in boundary conditions for a composite beam piezostructure.
Bioactive and Degradable Composite Microcarriers for 3-D Bone Tissue Engineering in Simulated Microgravity
Authors: Qiu Qing-Qing , Ducheyne Paul , Ayyaswamy Portonovo S. 
Published: December 2021

Abstract
Microcarriers currently used in cell and tissue cultures in microgravity environment simulated by rotating-wall bioreactors are primarily biocompatible polymers. For bone cell cultures and tissue formation, bioactive glasses and ceramics have unique advantages, such as bone bonding ability and stimulation of bone cell functions.1 However, they are difficult to be processed into spherical microcarriers and have not been used in simulated microgravity environment until recently.2 In this study, we developed composite microspheres by incorporating bioactive glasses and ceramics into a polymer microsphere to combine the osteoconductivity of bioactive glasses and ceramics with the ease of polymer processing. In addition, the wide range of mechanical and biological properties of polymer offers the possibility of making composite microspheres with various desired properties, such as biodegradation.
Another important factor in the microsphere design is the density of the microcarrier. Previous numerical analysis of the particle dynamics in a rotating-wall bioreactor has revealed that the shear stress imparted to a microcarrier increases with the density difference between the microcarrier and the culture medium.34 Solid ceramic particles would experience a high shear stress due to their high density and, as a results, affect cell attachment and cause cell damage.4 To alleviate the problem, microcarriers with a density close to that of the culture medium are desired. By combining biodegradable polymer with bioactive glasses and ceramics, the density of the composite microsphere could be adjusted and significantly reduced in comparison to solid ceramic microspheres.
In this study, we report development and characterization of novel bioactive and degradable composite microspheres for 3-D bone tissue engineering in simulated microgravity environment.
Using Encapsulation to Improve the Viability of Cryopreserved Cells
Authors: Matsumoto Yoshifumi , Morinaga Yukihiro , Ujihira Masanobu , Oka Kotaro , Tanishita Kazuo 
Published: December 2021

Abstract
The purpose of this study is to clarify whether encapsulated cells have an advantage over suspended cells in cryopreservation. Rat pheochromocytoma (PC12) cells were selected for test biological cell and microencapsulated in alginate-polylysine-alginate membranes. Microencapsulated PC12 cells were frozen with differential scanning calorimetry (DSC) at a cooling rate of 0.5 to 10°C/min, their latent heat was measured among the freezing process over the temperature range 4 to −80°C. Their post-thaw viability were evaluated by dye exclusion assay and dopamine release. As a result, latent heat of encapsulated cells was lower than that of suspended cells at a cooling rate of 0.5 and l°C/min. This is because extra-capsule was frozen and intra-capsule unfrozen, as ice crystals forms in extra-capsule space. Post-thaw viability of microencapsulated PC12 cells was improved at 0.5 and l°C/min compared with that of suspended cells. Therefore, in microencapsulated PC12 cells, achievement of intra-capsule unfrozen condition during freezing leads to reducing the solution effect and improving the viability.
The Effect of Heat Induced Changes in Microwave Tissue Properties on Microwave Thermal Therapy for Prostate Cancer
Authors: Sherar M. D. , Chin L. , Kolios M. C. , Gladman A. S. 
Published: December 2021

Abstract
The delivery of heat to the prostate using microwave antennas is being investigated as an experimental treatment for prostate cancer. Tissue temperatures can be calculated by solving the bioheat equation with the volumetric power deposition of the antenna as an input. This heating pattern is expected to change during heating due to changes in the electrical properties of the prostate. We have measured the microwave properties of rat prostate as a function of temperature and time and applied these parameters to the solution of the bioheat equation. We describe the nature of the changes in prostate tissue properties with heating. In addition, we present simulations of microwave heating in prostate tissue which illustrate the significance of including heat induced changes in tissue properties for this thermal therapy application. The prostate tissue measurements were performed using a loaded coaxial cable technique where the tissue sample could be rapidly heated as measurements were taken. Prostate treatment simulations were performed using a finite element approach to the bioheat equation.
An Apparatus for Measuring the Effective Thermal Conductivity of the Body Surface
Authors: Cheng Shuxia , Zhang Hongbo , Luo Dawei , Gao Dayong 
Published: December 2021

Abstract
To prevent body from injury during the hyper- and hypo-thermic therapy, knowledge of the temperature distribution in the body surface (e.g. skin or tissue) close to the therapy location is needed. In order to predict, by calculation, the correct temperature field, it is essential to input meaningful values of the thermal properties of the body surface into numerical and analytical simulation models of its behavior during heating or cooling. A simple experimental apparatus for measuring effective thermal conductivity of the body surface has been developed. It differs from the previously developed apparatus. In experiments, a fine platinum wire (0.01 mm in diameter) with electrical resistance R (0.4Ω)is embedded between a tested specimen (body surface) and a silicone rubber. When the wire, specimen and rubber are in thermal equilibrium, and a constant electrical power is applied to the wire, the temperature increase of the wire against logarithm time in predetermined time interval was measured. The kinetics of this temperature rising is related to the thermal conductivity of the tested specimen and silicone rubber. The thermal conductivity of the silicone rubber is known from reference or measured. So the thermal conductivity of tested specimen can be calculated by measuring the temperature rise of platinum wire at predetermined time interval. It is assumed that (1) the wire is infinite long and the heat source is steady, (2) the tested medium (e.g. the tested specimen and the silicone rubber) are infinite large in space, and contact resistance between the fine wire and soft medium is negligible.
The apparatus’ validity has been demonstrated by the following tests. First, as the standard specimen, thermal conductivity of glycerol and fused quartz glass (99.9% SiO2) were respectively measured using the apparatus. The relative errors between measured thermal conductivity and data provided by Thermophysical Properties Research Center (TPRC) are less than 0.7%. The validity of the theory model was also confirmed using several inorganic specimens and biological materials (e.g. rabbit sin, in vivo). Conditions and prerequisites for application of the technique and apparatus to measuring thermal conductivity of biomaterials (in vivo) were discussed.