bluuebunny/crossref_metadata_2025_split huggingface dataset:
Skin Heating Effects of Millimeter Waves: Inter-Species Variability
Authors: Nelson D. A. , Walters T. J. , Ryan K. L. , Johnson L. R. 
Published: December 2021

Abstract
The increasing use of radiofrequency signals in the millimeter wave (MMW) band in both defense and civilian applications necessitates a better understanding of the bioeffects of electromagnetic energy within this frequency range (30 GHz – 300 GHz). Because MMW irradiation penetrates less than 1 mm below the skin surface, the primary bioeffect is skin heating (1). Thus the use of the specific absorption rate (SAR) to establish safe exposure levels is not appropriate in this frequency band (2).
The use of animal models for evaluation of skin heating effects from MMW irradiation makes problematic the extrapolation of results to humans. Differences in tissue composition, skin blood flow, and surface cooling mechanisms (sweating) may complicate the interpretation of results obtained from animals and their application to humans.
This paper presents the results of series of experiments in rats, rhesus monkeys and humans to determine the rate of surface temperature increase resulting from exposure to MMW.
Numerical Results of an Integral Formulation of Transient Radiative Transfer
Authors: Tan Z.-M. , Hsu P.-F. 
Published: December 2021

Abstract
Numerical computations are performed for the transient radiative transfer equation within the one-dimensional parallel plate geometry using an integral formulation obtained in a prior work. The medium under consideration is absorbing and isotropically scattering. One boundary is a black emitting surface or a transparent surface subjected to the collimated incident radiation. The incident intensity is applied at the start of the transient. The other boundary is a cold and black or specularly reflecting surface. The spatial and temporal incident radiation and radiative flux distributions are presented for different boundary conditions and for uniform and nonuniform property distribution. The transient results at large time step are compared with steady-state solutions by the finite volume and quadrature methods and show excellent agreement. The solutions of reflecting boundary condition exhibit distinctive behavior from that of the non-reflecting boundary. The integral formulation is extended to handle the transient transfer within the nonhomogeneous participating media. The integral formulation has several advantages over the differential treatment of the hyperbolic wave of the radiative transport; among others: (1) The avoidance of using a high order upwind difference scheme in resolving the wave front; (2) Providing a sound basis for physical interpretation as the radiative transfer is a volumetric process; and (3) Many integral equation numerical methods that have previously been developed for the steady state integral formulation can be re-applied to treat the transient problem.
In Vivo Measurement of Microvessel Permeability and Tissue Diffusion Coefficient in Frog Mesentery by Confocal Microscopy
Authors: Fu Bingmei M. , Adamson Roger H. , Curry Fitz-Roy E. 
Published: December 2021

Abstract
Our early studies showed that tissue diffusion coefficient (Dt) of small solute sodium fluorescein (0.45 nm radius) in frog mesentery is 30% of its free diffusion coefficient (Dfree) in aqueous solution. We test here the hypothesis that because of its size-limiting structure the interstitium would provide larger resistance to larger solute α-lactalbumin (2.0 nm radius). We extended our previous method by using laser-scanning confocal microscopy to measure both solute capillary permeability (P) and solute tissue diffusion coefficients (Dt) from the rate of tissue solute accumulation and the radial concentration gradients around individually perfused microvessels in frog mesentery. pα-lactalbumin was 1.7 ± 0.7 (SD) × 10−6 cm/s (n = 6). Dt/Dfree was 27% ± 5% (SD) (n = 6). This value is comparable to that for small solute sodium fluorescein. Our results indicate that frog mesenteric interstitium is less selective to larger solute α-lactalbumin than the microvessel wall.
Diffusion-Limited Cell Dehydration: Analytical and Numerical Solutions for a Planar Model
Authors: Kasharin Alexander V. , Karlsson Jens O. M. 
Published: December 2021

Abstract
The process of diffusion-limited cell dehydration is modeled for a planar system by writing the one-dimensional diffusion-equation for a cell with moving, semipermeable boundaries. For the simplifying case of isothermal dehydration with constant diffusivity, an approximate analytical solution is obtained by linearizing the governing partial differential equations. The general problem must be solved numerically. The Forward Time Center Space (FTCS) and Crank-Nicholson differencing schemes are implemented, and evaluated by comparison with the analytical solution. Putative stability criteria for the two algorithms are proposed based on numerical experiments, and the Crank-Nicholson method is shown to be accurate for a mesh with as few as six nodes.
Enhanced Thermal Management Using Encapsulated Phase Change Materials: An Overview
Authors: Colvin David P. 
Published: December 2021

Abstract
Since 1983, investigators at Triangle Research and Development Corporation have pioneered the research and development of encapsulated phase change materials through 25 Small Business Innovation Research (SBIR) programs for NASA, DOD (USAF, NAVY, USMC, SDIO and SOCOM), NSF, USDA and HHS (NIOSH). Additional programs by licensees have also shown how these novel particles can produce superior apparel and coolant products. For pumped systems, two-component coolant slurries have demonstrated up to 40X (4,000%) improvement in the fluid’s effective thermal capacitance with up to 3X (300%) increase in the Nusselt Number within isothermal coolant loops for NASA, USAF and NAVY. MicroPCM machining coolants have also demonstrated enhanced heat transport along with significant reductions in tool wear, thermal distortions and coolant emissions for NSF and NIOSH.
For un-pumped passive systems, microPCM powders have been added to textile fibers, and apparel foams for 10X enhancement in thermal storage. MicroPCM coatings are being developed for numerous agricultural applications for NSF and the USDA. PCMs are also being macroencapsulated for garments in high heat stress applications with the USMC. Numerous products are now being introduced to global markets using this advanced technology. This paper will address the above applications in an overview that will also provide an introduction to the other papers in this session.
Damage Study in Notched Particulate Composite Specimens Under Non-Uniform Strain Loading
Authors: Kwon Y. W. , Liu C. T. 
Published: December 2021

Abstract
This paper studied crack initiation in a hard particle reinforced composite with a soft rubber-like matrix material using a numerical technique. The numerical specimen considered had a semi-circular notch with a linearly varying length. The initial crack size occurring at the notch tip was modeled and predicted using a micro/macro-approach along with a damage model. A criterion to predict the initial crack size was proposed based on the size of a localized unstable material zone. Different notch sizes were compared to their initial crack sizes.
Dynamic Stability of Multi-Tool Machining
Authors: Kushnir E. , Raj B. R. 
Published: December 2021

Abstract
The proposed numerical model of machine tool dynamic structure is constructed as a single-loop system consisting of two multi-dimensional links. This approach offers the advantage of considering all the working processes of the machine tool equally and simultaneously by placing them into a single multi-dimensional link. Employing matrix methods of analysis farther enhances the simplicity and universality of this methodology so that modern computer could be used for determining the dynamic qualities of the machine tools. The proposed methodology was validated by tests. The results of these tests are compared with data obtained from proposed computational approach.
A Multiple Term Viscoelastic Constitutive Model Implemented and Applied for Plastic
Authors: Verderber Rudy R. , Feng William W. 
Published: December 2021

Abstract
This paper discusses implementation and application of a multiple term viscoelastic constitutive model suitable for plastic materials. The constitutive model uses Feng’s recursive formula where the stress updates depend only on the stress terms in the prior state. The multiple term creep equations are accurate over longer periods of time. A tensile test simulation shows that the model provides reasonable results. Then a press fit example shows the holding force depends on time according to viscoelasticity.
MEMS Curriculum Development in Mechanical Engineering at the University of Michigan
Authors: Lin Liwei 
Published: December 2021

Abstract
MEMS curriculum development in Mechanical Engineering at the University of Michigan is presented. A course curriculum structure that integrates both mechanical and electrical engineering courses is proposed for mechanical engineering students who are interested in MEMS research. The proposed curriculum starts from undergraduate study and finishes at the Ph.D. level. Two new graduate-level MEMS courses are proposed. They are “Introduction to MEMS” for senior and entry-level, graduate students and “Advanced MEMS” for graduate students. The first course has been experimentally taught at the University of Michigan for the past three years and the class assessments are summarized and analyzed in this paper. It is clear from the student responses that for more advanced MEMS courses should be offered. The vision of the future MEMS curriculum development has also been discussed with the suggestion of the development a new undergraduate-level MEMS course in the college of engineering.
Assessing UV Exposure Limits for Surgical Luminaires
Authors: Fisher Kenneth J. 
Published: December 2021

Abstract
Research conducted at the University of Genoa has suggested that ultraviolet (UV) energy levels generated by Tungsten Halogen lamps may produce skin cancer. Similar threshold limit values for exposure to UV radiation have been reported by the American Conference of Governmental Industrial Hygienists (ACGIH) covering the spectral region of tungsten halogen emissions.
Such information has led to safety concerns by users of surgical lighting systems. It was deemed necessary to conduct an investigation regarding the possible effects of long term exposure to UV emitted by surgical luminaires.
The investigation included a review of materials used in the optical design of surgical luminaires related to the degree of filtration of UV transmission posed by the design and a measurement of UV radiation levels for a worst case exposure scenario.
The results of the investigation indicate that UV exposure levels from surgical lighting systems are within the levels of safe usage per guidelines established by ADGIH. It is concluded that surgical luminaires sufficiently reduce UV exposure to preclude the potential of adverse health effects.
Codes and Practice of Fatigue Design for Welded Structures
Authors: Sakamoto Haruo 
Published: December 2021

Abstract
This paper describes the codes and practice for designing welded structures such as railroad truck frames. For designing the first configuration, rather simple criteria are desired, although most codes such as AWS. AISC, etc. are complex. They consist of a variety of welded joint categories, which make a designer feel uncomfortable when deciding the first configuration. Therefore, such codes are considered to be mainly used for the evaluation of designed and constructed structures, and not to be used for deciding the first configuration. The JIS (Japanese Industrial Standard) for a railroad truck frame is explained as an example of a simple code, and is compared with some fatigue data. This standard is thought to be useful for a designer. However, the result of this investigation suggests a modification of the JIS for obtaining more reasonable criteria.
Desirable criteria should be simple for a designer and sufficiently safe for structures. Additional investigations on fatigue data of welded joints, a statistical study for desirable non-fracture probability, and methods of structural stress analysis are to be conducted in the future. A practical fatigue testing method is also needed for investigating the strength in a high cycle region such as 108.
An Accurate Approximation of the Orowan Rolling Force Equation for Homogeneous Compression of Metals in Cold Rolling
Authors: Urso André C. 
Published: December 2021

Abstract
The theory of rolling metals has been adequately developed since the mid 1940’s. Of the popular theories, the complex formulations are accurate over a large range of rolling conditions, and the approximate formulations tend to be accurate only on a narrow range. This paper covers the development of an approximate formulation of the Orowan (1943) rolling theory that is applicable over a relatively large range of reductions, material strengths, and strip tensions.
A New Approach to Mechanical Structure Approximation Analysis With Global Characteristics
Authors: Xiao Shide , Lu Jingui , Chen Jim X. , Gao Dayong 
Published: December 2021

Abstract
In this paper it has been theoretically proved that a three layer neural network can be applied to implementing exactly the function between the stresses and displacements and the design variables of any mechanical elastic structure based on Kolmogorov’s mapping neural network existence theorem. A new approach to the mechanical structure approximation analysis with the global characteristics based on artificial neural networks is presented. It has been verified by computer simulation experiments that the new approach is effective.
Decomposition and Reconstitution Based Fixturing Planning Automation
Authors: Huang K. , Rong Y. 
Published: December 2021

Abstract
Fixturing planning has become a focus in concurrent engineering which is required for efficient and effective product design, process planning and fixture design. In the context of DFM in concurrent engineering, a new Decomposition and Reconstitution (D&R) Based Fixture Planning Automation is developed as a top-down approach for fixture design automation. Decomposition and reconstitution problems are discussed for building a prototype fixture planning system. Finally a practical example is given to show its application process and effectiveness.
Improving the Economics of Machining PMMCs
Authors: El-Gallab Mariam S. , Sklad Mateusz P. 
Published: December 2021

Abstract
It is the purpose of this paper to present a mathematical model for the prediction of surface finish during turning 20%SiC/Al particulate metal matrix composites (PMMCs). The surface finish relation to the cutting parameters (tool material, tool geometry, speed, feed rate and depth of cut) is further employed in a general form for tool life in order to arrive at optimum cutting parameters that would cost the least and yet meet the surface roughness requirements. A simple C++ program has been developed to find the optimum cutting conditions iteratively. The mathematical models quantify the results of an extensive experimental work on oblique turning of the SiC/Al PMMCs. The results of the experimental work reveal that increasing the feed rate up to 0.55 mm/rev. improves the tool wear rate. This is attributed to the reduced area of contact between the tool surface and the abrading SiC particles. Further increases in the feed rate results in tool failure by edge chipping. The optimum cutting conditions arrived at by the mathematical model yield 21–37% cost reduction when compared to the currently employed cutting parameters.
Modeling of Gear Hobbing: Part I — Cutting Simulation and Tool Wear Prediction Models
Authors: Bouzakis Konstantinos D. , Kombogiannis Spiros , Antoniadis Aristomenis , Vidakis Nectarios 
Published: December 2021

Abstract
Gear hobbing is the most common method to manufacture high quality and performance toothed wheels. The gear hobbing kinematics induces complicated chip formation and is characterized by convoluted wear mechanisms of the cutting tool. The variant cutting contribution of each cutting tooth is responsible for the uneven wear distribution on the successive hob teeth and the poor utilization of the entire cutting tool. Moreover, the gear width influences the chip geometry in the tool entry and exit regions into the workpiece, and sets a mathematical wear description even more complicated. To study quantitatively the tool wear progress in gear hobbing, experimental-analytical methods have been established. Gear hobbing experiments and advanced mathematical models are hired to correlate the undeformed chip geometry and other cutting parameters with the anticipated wear. With the aid of such procedures and of appropriate constants, essential for the description of the wear development in the individual gear gaps generating positions, an optimization of the hobbing process can be achieved. Hence, among others, appropriate tangential shifts of the hobbing tool may be predicted.
Modeling of Gear Hobbing: Part II — A Computer Supported Experimental-Analytical Determination of the Wear Progress to Optimize the Tool Life Time
Authors: Bouzakis Konstantinos D. , Kombogiannis Spiros , Antoniadis Aristomenis , Vidakis Nectarios 
Published: December 2021

Abstract
Tool wear prediction models for gear hobbing were presented in the first part of this paper. To determine the constants of the equations used in these models, fly hobbing experiments with uncoated and coated HSS tools were conducted. Hereby, it was necessary to modify the fly hobbing kinematics from continuous tangential feed to continuous axial feed. The experimental data were evaluated, and correlated to the analytical ones, elaborated through the described digital simulation of the cutting process. The determined constants of the wear laws for the investigated tools were used in a further developed user friendly software, enabling the prediction of the tool wear accomplishment in gear hobbing. On that account the wear development can be precisely foreseen and the tangential shift of the tool is optimized. The open and modular structure of the developed code enables the continuous enrichment of its database with other type of coating and workpiece materials. With the aid of the aforementioned techniques, the superiority of coated HSS tools in comparison to uncoated ones is also quantitatively exhibited.
Generalized Modeling of Milling Mechanics and Dynamics: Part I — Helical End Mills
Authors: Engin Serafettin , Altintas Yusuf 
Published: December 2021

Abstract
Variety of helical end mill geometry is used in industry. Helical cylindrical, helical ball, taper helical ball, bull nosed and special purpose end mills are widely used in aerospace, automotive and die machining industry. While the geometry of each cutter may be different, the mechanics and dynamics of the milling process at each cutting edge point are common. This paper presents a generalized mathematical model of most helical end mills used in industry. The end mill geometry is modeled by helical flutes wrapped around a parametric envelope. The coordinates of a cutting edge point along the parametric helical flute are mathematically expressed. The chip thickness at each cutting point is evaluated by using the true kinematics of milling including the structural vibrations of both cutter and workpiece. By integrating the process along each cutting edge, which is in contact with the workpiece, the cutting forces, vibrations, dimensional surface finish and chatter stability lobes for an arbitrary end mill can be predicted. The predicted and measured cutting forces, surface roughness and stability lobes for ball, helical tapered ball, and bull nosed end mills are provided to illustrate the viability of the proposed generalized end mill analysis.
On the Dynamic Stability of Nonlinear Chatter Machining
Authors: Fofana M. S. 
Published: December 2021

Abstract
This paper is concerned with the dynamic stability of nonlinear chatter leading to instability machining at a Hopf bifurcation point. Regions of stable and unstable chatter machining are identified in an infinite-dimensional space for a reasonable and fixed time delay between successive cuts. The influence of nonlinear cutting force as a function of the chip thickness and feed rate, and parametric excitations on machining dynamics have been characterized.
Experimental Study of Superfinishing
Authors: Chang Shih-Hsiang , Farris Thomas N. , Chandrasekar Srinivasan 
Published: December 2021

Abstract
An experimental study has been made of the superfinishing process. A force measurement system, developed for external cylindrical superfinishing, has been used to directly measure the forces acting on the abrasive stone. A systematic parametric study of material removal rate, force ratio, specific energy and surface finish is detailed. The force ratio and specific energy are found to be sensitive indicators of the cutting action of the stone. This indicates that the force ratio could be used to monitor the process, online in industrial applications. The two regimes of rough finishing and fine finishing have been characterized. A sharp transition from fine to rough finishing occurs at a stone oscillation frequency of about 1600 cpm. This characteristic frequency is mostly independent of stone-work contact pressure. The experimental data is used to construct a superfinishing process map, analogous to the wear-regime map, to depict the various regimes in which different modes of superfinishing dominate.
High Speed Grinding of Silicon Nitride With Electroplated Diamond Wheels: I — Wear and Wheel Life
Authors: Hwang T. W. , Evans C. J. , Whitenton E. P. , Malkin S. 
Published: December 2021

Abstract
An investigation is reported on high speed grinding of silicon nitride using electroplated single-layered diamond wheels. The present paper is concerned with wheel wear and wheel life, and a second paper (Hwang et al., in press) with wheel topography and grinding mechanisms. It has been suggested that grinding performance may be enhanced at higher wheel speeds due to a reduction in the undeformed chip thickness. Grinding experiments were conducted at wheel speeds of 85 m/s and 149 m/s with the same removal rate. Contrary to expectations, the faster wheel speed gave no improvements in surface finish, grinding ratio, or wheel life. Microscopic observations of the wheel surface revealed dulling of the abrasive grains by attritious wear, thereby causing a progressive increase in the forces and energy until the end of the useful wheel life. For all grinding conditions, a single-valued relationship was found between the wheel wear and the accumulated sliding length between the abrasive grains and the workpiece. A longer wheel life and improved grinding performance can be obtained when the operating parameters are selected so as to reduce the abrasive sliding length per unit volume of material removal.
Solidification Modeling and Porosity Control in Aluminum Alloy Castings
Authors: Shenefelt Jeffrey R. , Luck Rogelio , Berry John T. , Taylor Robert P. 
Published: December 2021

Abstract
Commercial software packages enable the thermal environment of shaped castings to be determined provided the boundary conditions are well understood. Criteria functions (CF’s) based on the thermal environment provide a means for estimating shrinkage porosity within a casting. However, the CF’s do not account for gas driven porosity forming within the casting. This paper reviews the CF’s and additional approaches to account for hydrogen evolution in aluminum-copper and aluminum-silicon alloys.