bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiative Transfer Between the Pulsed Laser and the Target in the Presence of Laser-Induced Plasma
Authors: Xu Xianfan , Song Kevin H. 
Published: July 2023

Abstract
When high power, pulsed laser interacts with materials, a condensed plasma layer is generated above the target surface. The laser-induced plasma changes the energy coupling mechanisms between the laser beam and the target. This work investigates the radiative heat transfer process in the plasma layer generated by laser irradiation. Novel diagnostic techniques are developed to measure the transient transmission and scattering of the thin plasma layer within the duration of the laser pulse. Based on the measurements radiative heat transfer analysis is performed to evaluate the radiative properties of the plasma layer, including the optical depth, the absorption coefficient, the single scattering phase function, and the scattering size parameters. Knowledge on these radiative properties help to understand the energy transfer process during laser materials interaction. Further this work demonstrates the feasibility of using the transient scattering measurement for in-situ monitoring of the diameter of the laser ejected particles.
Projection Micromachining of Polyimide Thin Films by an Excimer Laser
Authors: Zhang X. , Grigoropoulos C. P. , Krajnovich D. J. , Tam A. C. 
Published: July 2023

Abstract
A KrF excimer laser projection micromachining tool has been designed and implemented aiming to accomplish one-step etching with micron resolution for applications such as chip module packaging and polyimide technology in semiconductor manufacturing. Two polyimide thin films spun on the silicon wafers are annealed at 100 °C and 400 °C, respectively, in order to investigate the effect of the annealing temperature on the laser micromachining process. The micromachined polyimide surface morphology is studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and a surface profilometer for determination of the etch rate at different laser fluences. Micromachining with micron resolution is achieved by this excimer laser projection tool. Measured on a 25 μm line, the etch rate dependence on laser fluence both below and above the ablation threshold is investigated over the fluence range from 10 to 1000 mJ/cm2. The polyimide thin film optical properties, n and k at λ = 248 nm are measured by a spectroscopic ellipsometer for both films. The etch rate above the ablation threshold for the film annealed at 100 °C is found 60% higher than that for the film annealed at 400 °C. This behavior originates from the correspondingly higher by 82% absorption coefficient, α in the 100 °C film. The ablation thresholds for both films are found the same at about 100 mJ/cm2. Calculated etch rates agree with experimental values within 15%. Etch rates of the order of nanometer can be achieved near the ablation threshold of 100 mJ/cm2 for both films.
Surface Contaminant Removal Using Short-Pulse Lasers
Authors: Phinney Leslie M. , Tien Chang-Lin 
Published: July 2023

Abstract
New methods of removing surface contaminants from micro-electronic and microelectromechanical system (MEMS) devices are needed since the decreasing size of their components and structures is reducing the allowable contamination levels. If the pulse duration and fluence are chosen to optimize electronic rather than thermal desorption in short-pulse laser processing, surface species can be removed without exceeding maximum temperature constraints. A two-temperature model for short-pulse laser heating of, and subsequent desorption from, metal surfaces is presented. A scaling analysis indicates that the ratio of electronic to thermal desorption depends on three ratios: the electron and lattice specific heats, the laser pulse duration and electron-lattice thermalization time, and the radiation penetration depth and film thickness. Regimes of predominantly electronic and thermal desorption are identified, and predicted desorption yields from gold films show that electronic desorption is the primary desorption mechanism in certain short-pulse laser processes.
Microelectronic Chip Attach With Silver Filled Epoxies: An Analytical and Experimental Study
Authors: Zwick K. J. , Ayyaswamy P. S. , Cohen I. M. 
Published: July 2023

Abstract
In microelectronic chip packages, a mechanical bond between the chip and the leadframe is formed by depositing a pattern of epoxy drops on the lead frame, and then placing the chip on top of the epoxy. A small force is applied to the top of the chip which causes the epoxy to squeeze out under the chip and form a complete, void-free bond between the chip and the lead frame. In this paper, we analyze the squeezing flow of the bonding epoxy, and demonstrate that the bonding time is longer for large chips than for small chips. We also present the results of some related experiments on the squeezing flow of the epoxy. We find that the squeezing behavior predicted by our analysis agrees very well with the measured behavior under typical bonding conditions. Finally, we discuss two methods of reducing the bonding time, and the advantages and disadvantages associated with each of these methods.
Temperature Distributions in Rods Within an Optical Fiber Draw Tower Furnace
Authors: Mungekar H. P. , Polymeropoulos C. E. 
Published: July 2023

Abstract
The present work is motivated by the current need of increasing the yield of optical fiber drawing by using high draw speeds. For such conditions the preform feed rate through the draw tower furnace can affect the heat transfer to the preform rod and as a consequence the formation of the neckdown. In the present work temperature distributions along the axis of stationary as well as moving graphite and fused silica rods inserted in a fiber optic draw tower furnace was found experimentally. Experimental data clearly showed that the thermal lag increased at higher draw speeds. Implications of this to high speed fiber drawing are highlighted. Measured temperatures were compared with numerically computed temperature distributions in moving rods. Excellent agreement was found between the temperature recorded in moving graphite rod experiments and the computed temperatures which validated the furnace temperature profile found in the previous work. However, for glass rods the computed temperature lag was greater than the measured temperature lag. The difference between computed glass temperatures and those measured using a thermocouple was explained using a simplified modeling taking into account spectrally selective radiation properties of glass.
Flow Behavior and Heat Transfer of Atomizing Gas and Metal Droplets in Spray Forming Process
Authors: Cui Chengsong , Shen Jun , Xu Daming , Li Qingchun 
Published: July 2023

Abstract
The dynamics for the fluid flow and heat transfer in spray forming process is theoretically analyzed and the controlling equations of the flow and heat transfer are derived. The shape/geometry and the solidification profiles such as temperature and remained liquid in the preform are calculated by the simulation of the controlling equations. The predicted cooling rates at different positions can reach 102−103 °C /s at the beginning of deposition and decrease to 100∼101 °C/s in the subsequent cooling process. The characteristics of rapid solidification structures with spray forming are mainly due to the high cooling rate of droplets during spray process (&gt;104 °C /s) and breaking mechanism of dendrite on deposition.
Simulation of Micro-Pore Formation in Spray Deposition Processes
Authors: Delplanque J.-P. , Lavernia E. J. , Rangel R. H. 
Published: July 2023

Abstract
The present work investigates porosity formation in spray deposition processes. The emphasis is on one possible mechanism of micro-pore formation during droplet spreading and solidification: liquid-jet overflow. To this end, the Navier-Stokes equations are solved numerically using finite differences and the free surface is tracked using the Volume Of Fluid method. A previously developed multi-directional solidification algorithm is adapted and implemented in the Navier-Stokes solver to perform numerical simulations of liquid-metal droplet impact, spreading, and solidification. The results obtained allow a detailed description of the liquid-jet overflow mechanism and of the resulting solidified disk morphology. The influence of the Weber and Reynolds numbers, the solidification constant, and the contact angle is investigated.
Simulation of Phase Change and Convective Heat Transfer in Float Zone Processing
Authors: Rao Madhukar M. , Shyy Wei 
Published: July 2023

Abstract
A computational capability has been developed to predict the free surface shape, heat transfer and melt-crystal interface shapes in float zone processing. A moving boundary, second order, finite volume, incompressible Navier-Stokes solver has been developed for the fluid flow and heat transfer calculations. The salient features of the approach include solving the dynamic form of the Young-Laplace equation for the free surface shape, dynamic remeshing to fit the free boundary, a flexible, multi-block, grid generation procedure and the enthalpy method to capture the melt-crystal and the melt-feed interfaces without the need for explicit interface tracking. Important convective heat transfer modes; natural convection and thermocapillary convection have been computed. It is shown that, whereas the overall heat transfer is not substantially affected by convection, the melt-crystal interface shape acquires significant distortion due to the redistribution of the temperature field by the thermocapillary and buoyancy-induced convective mechanisms. It is also demonstrated that the interaction of natural and thermocapillary convection can reduce the melt-crystal interface distortion if they act in opposing directions.
Numerical Simulation of Temperature Field of Copper and Copper Alloy in Horizontal Continuous Casting
Authors: Wenhua Xie , Shuisheng Xie , Shenghong Huang 
Published: July 2023

Abstract
To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models, describing the thermal process, have been developed. Then Finite Element Method (FEM) has been applied to simulate the solidification proceess.
Parameters included casting speed, casting temperature and cooling conditions, have been analysized. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental results.
Simultaneous Three-Wavelength Interferometry for Head/Tape Spacing Measurement
Authors: Baugh Eric , Talke Frank E. , Swenson James 
Published: July 2023

Abstract
Instrumentation for the simultaneous acquisition of three monochromatic interference patterns is described. An algorithm to process the three images using a weighted average method into a map of the head/tape spacing and an estimated contact pressure map is presented. Both experimental evidence and Monte-Carlo simulation indicate that the three-wavelength technique is an improvement over standard monochromatic techniques. Sample one- and two-dimensional measurements are given.
Quantification of Standing Wave Patterns in Rotating Flexible Disks Using Optical Reflection Techniques
Authors: Ma Yiping , Thomas Fred C. 
Published: July 2023

Abstract
This paper is a follow-on to a paper previously presented to ASME on an experimental instrument designed to enable the observation of standing wave modes for flexible media. In that earlier paper qualitative results showing changes in the disk standing waves were obtained using the experimental setup. The current paper presents the same experimental system from the perspective of looking at the system as an optical instrument, and, based on optical ray trace methodology, quantifies the results seen in the previous paper on a more absolute basis. Based on this analysis, the authors also describe design changes from both an instrument setup perspective and the application of other electro-optic sensor technologies which will improve the system’s static and dynamic resolution.
Frequency Domain Characterization of Take-Up Reel Air-Entrainment in Low-Tension and High-Speed Tape Transport
Authors: Mathur Priyadarshee D. , Messner William C. 
Published: July 2023

Abstract
Air entrainment in tape spooling is important in determining tape stacking quality and in modeling the transport system for control purposes. Accurate estimates are difficult to obtain by direct measurement. In this paper, the length of the entrained air film is estimated by determining the spring constant of the unsupported tape span. Using multi-input single-output (MISO) frequency based system identification, the resonant frequency of the system associated with the longitudinal mode of the tape is derived. This data is compared to predictions from the well known nip equation. The utility of these equations is discussed.
Effects of Inserting Arm Blockage on Heat Transfer in a Corotating Disk Assembly
Authors: Chyu M. K. , Hsing Y. C. 
Published: July 2023

Abstract
To advance disk drive design for increased performance and reliability, a thorough understanding of flow and thermal transport in the disk file is essential. The primary objective of this study is to examine the effects of slider arm blockage on the convective characteristics in a 3.5-inch corotating disk stack. Using an analogous mass transfer system based on naphthalene sublimation, the detailed distribution of local mass transfer coefficient over the disk surface is determined by an automated micropositioning system. By analogy, the mass transfer coefficient can be transformed to the corresponding heat transfer coefficient and friction coefficient. All the transport coefficients reveal strong variation with the arm blockage in the radial direction. However, overall average transfer coefficient obtained by integrating their corresponding local values are rather insensitive to the extent of arm protrusion.
A Parametric Study Addressing the Three-Dimensional Components of Spinal Loading During Complex Dynamic Lifting Tasks
Authors: Fathallah F. A. , Marras W. S. , Parnianpour M. 
Published: July 2023

Abstract
Increasing evidence indicates that spinal shear forces are important risk factors in occupationally-related low back disorders (OLBDs). This paper demonstrated how ignoring these forces and focusing only on compressive loading could severely under-represent the complete mechanical exposure to the spine. A parametric scheme is proposed to consider the combined 3-D forces during dynamic lifting tasks. As more complete tolerance data become available, loading limits that reflect such information may be determined. This would help in finding the best means to assess the effects of spinal loading and would thereby be useful in reducing back disorders in industry.
Dynamic Response of an L2-L3 Motion Segment to Compressive Cyclic Loading Using a Nonlinear Viscoelastic Finite Element Model
Authors: Wang J. L. , Shirazi-Adl A. , Parnianpour M. , Engin A. E. 
Published: July 2023

Abstract
The axial compressive cyclic loading was applied to a nonlinear viscoelastic finite element model of an L2-L3 motion segment to investigate its dynamic response. In this validated model, the material properties of the anulus matrix, anulus fibers and nucleus pulposus (NP) have been represented by the viscoelastic constitutive laws. The detailed stress-strain analysis of the motion segment under cyclic loading was performed to quantify the load sharing amongst passive elements. The cyclic loading encountered due to exposure of vibration or during driving has been implicated as a risk factor for occupational low back disorders (OLBD). The cyclic axial compressive loading was controlled, peak to peak, from 600 N to 1000 N at 0.5 Hz for 15 cycles (30 seconds). The results indicated that the axial stiffness of the motion segment decreased, while intradiscal pressure (IDP) and the strain of the anulus fiber increased.
Realistic Virtual Reality Simulation of Touching Hard Tumors Beneath Soft Tissue
Authors: Dinsmore Michael , Langrana Noshir , Burdea Grigore 
Published: July 2023

Abstract
Touch has always been central to many aspects of medical practice. The surgeon working deep inside the abdominal cavity will feel and squeeze the liver to determine which, if any, nodule to biopsy. Palpation of a female breast is a sensitive means for detecting malignancies. Surgeons and pathologists routinely take advantage of the fact that cancers feel different than normal tissue.
Cervical Spine Laminectomy and Facet Wiring
Authors: Yoganandan Narayan , Cusick Joseph F. , Pintar Frank A. 
Published: July 2023

Abstract
Using physiologic compression-flexion loading, eight human cadaver cervical spinal columns (C2-T1) were tested under intact, laminectomy, and facet wiring conditions. Forces, displacements, and the overall and local kinematics of the spinal components at every level of the column were obtained. Laminectomy decreased the stiffness and increased the overall local spinal motions (p &lt; 0.05). Individual facet wiring to bone graft and through the spinous process inferior to laminectomy did not restore the stiffness and overall sagittal rotations. In contrast, the Luque rectangle induced stiffness changes to levels exceeding the intact preparations and reduced the sagittal rotations. The significant increases in the total column flexibility and the segmental flexion rotations secondary to laminectomy were most effectively corrected by the cross-linking of the facet wire fixation above and below the laminectomized segments and not by the individual facet wires secured to an overlying structure.
Finite Element Analysis of Cervical Laminectomy With Graded Facetectomy
Authors: Kumaresan Srirangam C. , Pintar Frank A. , Yoganandan Narayan 
Published: July 2023

Abstract
This study was undertaken to investigate the biomechanical effects of the human cervical spine under intact, and laminectomy with and without graded facetectomy conditions. An anatomically accurate finite element (FE) model of a three-segment (C4-C6) spine unit was developed. The FE model was validated under physiologic flexion, extension, lateral bending, and axial torsion loading modes. The model response matched well with the experimental data. The gross external (angular rotation) and the internal responses (e.g., superior and inferior intervertebral disc stress) were delineated under these physiological loading modes. Laminectomy markedly altered the cervical angular motion and the disc stress under flexion loading compared to the other loading modes. Laminectomy with facetectomy increased the angular motion and the inferior disc stress notably under flexion without affecting the adjacent superior disc. Facet resection of more than 50 percent caused pronounced increase of angular rotation and intervertebral disc stress.
Development, Validation and Clinical Relevance of a C5-C6 Motion Segment Finite Element Model
Authors: Clausen John D. , Goel Vijay K. 
Published: July 2023

Abstract
A fully three-dimensional finite element (FE) model of a C5-C6 human cervical spine motion segment has been developed and validated. This model is the first to incorporate many of the important biomechanical aspects of the cervical spine not represented in previous models. To demonstrate the models’ predictive power we have addressed a variety of clinical issues including injury and stabilization. Additionally, the loading paths from one vertebra to another are fully described in multiple modes of loading. Knowledge of loading paths will allow injury and stabilization to be characterized in a manner previously not possible.
Our model represents significant and essential advancements over previous FE models of the cervical spine making it possible to address a broad spectrum of clinically relevant issues which could not be investigated in the past.
A Viscoelastic Model for the Natural History of Adolescent Idiopathic Scoliosis
Authors: Meade K. P. , Patwardhan A. G. , Gavin T. 
Published: July 2023

Abstract
Early detection of scoliosis through school screening programs sends a large number of young patients with mild curves to scoliosis clinics for evaluation. Only about 20 percent of the curves progress if not treated. Uncertainty in the prognosis for progression can result in unnecessary bracing of benign curves. In this paper, a new approach is described for modeling the natural history of idiopathic scoliosis, which could change this situation by predicting which curves progress and which do not.
Dynamic Biomechanics of Penetrating Trauma
Authors: Yoganandan Narayan , Pintar Frank A. , Kumaresan Srirangam , Hargarten Stephen , Sances Anthony 
Published: July 2023

Abstract
The objective of this study was to investigate the biomechanics of penetrating trauma secondary to high velocity projectiles. Tests were conducted using 10 percent ordnance gelatin as a human tissue simulant. Two different types of projectiles were discharged into the gelatin block which was prepared with centrally placed nylon strings. A digital high-speed camera capable of recording up to 40,500 frames per second documented the path and the associated secondary wave effects. The data were analyzed with respect to the entrance and exit velocities, the time-varying velocity in the gelatin, and the penetration profile characteristics including the residual wound involvement. Depending on the design and construction of the projectile, a stark contrast in the dynamic effects was found. Results from these studies have the potential to delineate the biomechanical effects of high velocity projectiles and develop standards to ameliorate trauma secondary to the discharge.
Validation of Experimental Methods for Determining Inertial Properties of Human Subjects
Authors: Marsh M. Virginia , Todd Beth A. , Rasmussen Roy R. , Baughn Donna Jo , Albery Chris 
Published: July 2023

Abstract
Due to an expansion in the pilot population allowed to fly fighter aircraft, there is a need to measure whole-body centers of gravity and moments of inertia of individuals to determine the safety of ejection seats for this broader population. An adjustable seating system has been developed by the Vulnerability Assessment Branch of Armstrong Laboratory (AL/CFBV) and Systems Research Laboratory (SRL) located at Wright-Patterson Air Force Base (WPAFB) which can be used to measure the center of gravity and moments of inertia of an individual about any of three orthogonal axes. The accuracy of the technique has been verified with the use of two 68 kg (150 lb) test specimens, and it has been approved for human use. Results for a 62.6 kg Caucasian male subject compare well with those found in the literature for a 5th percentile Caucasian male (65.2 kg/143.7 lb) (NASA, 1978).
Low Cost Pressure Gauges
Authors: Dann-Johnson Summer , Johnson Wayne , Luckham Mike , Marsh Kristen 
Published: July 2023

Abstract
A design of a pressure measurement device to be used in balloon esophageal dilatation which has a mass produced cost of less than $4.60 per unit was required. A project budget of $500.00 was allotted for prototype development and research expenses. Two designs, a mechanical device and an electronic device, were selected for prototype development. The prototypes were fabricated and tested for repeatability and accuracy.
A Computational Study of the Flow in Branching Channels and Tubes
Authors: Hassan Amgad A. , Evrensel Cahit A. 
Published: July 2023

Abstract
Turbulent flow through a 3-D bifurcating circular tube and 2-D rectangular channel are computed. In both cases, the bifurcating angle was 604dG and parent to daughter diameter (tube) and channel height ratios were 1.4. These values correspond to the physiological averages. The results showed flow separation in the daughter branch in both cases and relatively strong secondary flow for the bifurcating tube. Also, the average velocity at the exit of the daughter branch was relatively smaller than the main branch for the tube, while these values were comparable for the rectangular channel.