bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Study of Effects of a Bellmouth on the Entrance Flow in a Circular Pipe
Authors: Kanda Hidesada 
Published: January 2022

Abstract
The flow characteristics in the bellmouth region of a circular pipe have been numerically studied for Reynolds numbers, Re, ranging from 1000 to 4000. Until now, the axial velocity has been assumed to be uniform at the bell-mouth outlet both experimentally and theoretically. The calculation results, however, reveal that it develops a profile somewhat towards the Poiseuille’s parabolic profile. Next, it was found that the pressure on the wall of the bellmouth is lower than in the central core. This result contradicts both Bernoulli’s law and Prandtl’s boundary-layer assumption. Moreover, a feasible reason for the increase in critical Reynolds number when using bellmouths was identified, i.e., if the bellmouth region is replaced by the pipe one, it was observed that the equivalent Re decreases from the original Re value.
Unsteady Pipe Flows of a Viscoplastic Non-Newtonian Fluid: Effects of Pressure Gradient Waveform
Authors: Hammad Khaled J. 
Published: January 2022

Abstract
Unsteady flows of a Bingham non-Newtonian fluid through a circular pipe have been studied numerically. These flows are impulsively started from rest via imposing a cyclic pressure gradient having a specific waveform. Triangular, sinusoidal, and square waves were considered, each varying around a non-zero mean value corresponding to the steady-state one. The parameters varied in this study are the amplitude of the time varying pressure gradient (8), Strouhal (St), Reynolds (Re), and Yield (Y) numbers within the following range: 1 &lt; ε &lt; 2, 0.1 &lt; St. Re &lt; 100, & 0 &lt; Y &lt; 10. Effects of these parameters on flow transients and asymptotic, i.e. pulsatile, flow field characteristics are demonstrated. Two relevant time scales are introduced, a momentum diffusion time scale, τυ = ρR2/ηp, and a periodic convective time scale, τc = 2π/ω. Time-averaged characteristics of the pulsatile flow field are presented as a function of the ratio τυ/τc. Those characteristics are determined to be quasi-steady-state, and steady-state like within the lowest and highest, respectively, of the studied τυ/τc values. Pulsating the flow of a Bingham fluid, within the low and intermediate τυ/τc ranges leads to substantially higher flow rates than the steady-state ones. This is true for all investigated waveforms with the lowest and highest increases corresponding to the triangular and square waves, respectively.
Experimental Determination of Added Mass in Different Directions of In-Situ Complex Objects With Non-Free Boundary Conditions
Authors: Lynch John 
Published: January 2022

Abstract
Added mass, or virtual mass, is the mass of fluid which moves with a submerged object when the object is accelerating or the fluid is accelerating around it. This concept is of interest many fields. Added mass is normally determined analytically by potential flow theory for relatively simple objects, or by experimental methods for more complicated objects. Even though the objects’ added mass applies to an object with no other objects around it and with uniform boundary conditions, the added mass may be determined experimentally even if the object is mounted rigidly at one end. That is the subject of this paper.
An Analytical Aspect of the Preston Equation
Authors: Hocheng H. , Tsai H. Y. 
Published: January 2022

Abstract
An analytic model of the material removal rate is proposed, and is found equivalent to the empirical Preston Equation reported in 1927 for the glass polishing. The effects of the applied pressure, the polishing velocity between the wafer surface and the pad surface, and the mechanical properties of material are identified. From the viewpoint of microscopic material removal, the material removal rate is proportional to the cubic of the true pressure loaded by a single abrasive, while the relationship is linear when the nominal polishing pressure between pad and wafer is considered.
Dimensional Fault Diagnosis for Compliant Beam Structure Assemblies
Authors: Rong Q. , Ceglarek D. , Shi J. 
Published: January 2022

Abstract
A model-based diagnostic methodology is proposed for the dimensional fault diagnosis of compliant beam-type assemblies in automotive or aerospace assembly processes. This method uses the measurement data to detect and isolate dimensional faults of compliant beam assemblies caused by part fabrication error and part-to-part interferences. The proposed method includes a predetermined fault patterns model and a fault mapping procedure. The fault patterns are modeled by the diagnostic vectors derived from the inversed stiffness matrix of the beam structure. The fault mapping procedure combines Principal Component Analysis (PCA) of measurement data and fault pattern recognition using statistical hypothesis tests. Verification of the proposed method is presented through simulations and one case study.
Fault Diagnosing of Large Rotating Machinery Using Evolutionary Spectrum
Authors: Jia Minping , Du R. 
Published: January 2022

Abstract
Fault diagnosis of large rotating machinery sets is very important for many industry sectors. However, it is also difficult because of its complexity. The conventional fault diagnosis methods are based on FFT spectral analysis. While its effectiveness has been approved by many applications, it also has significant limitations. In fact, it has been found that many faults have similar spectral patterns. In order to pinpoint the cause of the faults, it may be necessary to vary the speed to get additional information. Nevertheless, the speed variation makes the vibration signal non-stationary. This in turn makes the FFT spectral analysis imperative. In this paper, it is proposed to use a new technique, called evolutionary spectrum, to analyze the non-stationary signal and hence diagnose the faults. First, following a brief introduction of wavelet transform, the evolutionary spectrum is described. Next, the implementation procedure of the evolutionary spectrum is given. Then, by means of computer simulation and experiment results analysis, it is shown that the evolutionary spectrum can effective capture the fault patterns and hence, diagnose rotor unbalance and rotor stiffness asymmetric.
Intelligent Diagnosis of the Root Cause for Rejects in the Automatic Transmission Assembly Process
Authors: Chen Yubao 
Published: January 2022

Abstract
This paper presents a method for the diagnosis of reject root causes in automatic transmission assembly process based on the fuzzy multiple voting scheme. As the first step, data from all the valid test points were collected and studied based on their statistical characteristics. An information-gain-based procedure was followed to quantitatively evaluate the relevance of each test point to the diagnosis process. Accordingly, an objective rank of all relevant test points was generated for a particularly reject. The root cause of rejects was then identified by a procedure based on a fuzzy multiple voting classification algorithms. This method has been tested with top five rejects in a transmission assembly process and promising results have been obtained.
Thread Formation Mechanism by Planetary Conical Rolling
Authors: Mori Toshihiko , Nakashima Kunihiko , Abraha Petros 
Published: January 2022

Abstract
Planetary conical rolling, PCR, is a large deformation tube forming process that produces high accuracy products. PCR process can therefore be used to produce features on the surface of tubes without an overall distortion. In this research, forming of a thread feature on the surface of thin tubes is experimentally examined. The results show thread forming process is composed of three step by step stages that form a high precision tube surface features.
Thermal Modeling and Control of Material Processing in Scan Welding
Authors: Doumanidis Charalabos , Fourligkas Nikolaos , Korizis George 
Published: January 2022

Abstract
The paper focuses on thermal analysis of scan welding, a new joining technique redesigned to ensure the composite morphologic, material and mechanical integrity of the weld. This is obtained by real-time control of the temperature field by a proper dynamic heat input distribution on the weld surface. This distribution is implemented in scan welding by a single torch, sweeping the joint surface by a controlled reciprocating motion, and power adjusted by feedback of infrared temperature data in-process. A numerical simulation and an analytical multivariable model of the thermal field in scan welding is established, using real-time identification of its parameters. An adaptive thermal control scheme is thus implemented and validated computationally and experimentally on a robotic Gas-Tungsten Arc Welding setup. The resulting thermal features of scan welding are analyzed in terms of material structure and properties of the weldment.
An Analytical, Non-Dimensional Representation of Chip Area for Corner-Radiused Tools Under Depth-of-Cut and Feed Variations
Authors: Ozdoganlar O. Burak , Endres William J. 
Published: January 2022

Abstract
A new, analytical chip-area representation for corner-radiused tools under both depth-of-cut and feed variation is presented. This situation occurs for many tool geometries and under many practical conditions. Results obtained with the new model are compared to an exact area computation algorithm based on geometrical shapes. The new representation and its associated expressions are far more simple than those of the exact area representation. The errors introduced by the new representation are very small, and when a very simple error compensation term derived here is added, almost negligible for most conditions considered.
Environmentally Conscious Disposal Considerations in Cutting Fluid Selection
Authors: Skerlos Steven J. , DeVor Richard E. , Kapoor Shiv G. 
Published: January 2022

Abstract
Traditionally, negative environmental impacts of cutting fluid disposal have not been considered during cutting fluid selection. These impacts may result from hazardous chemicals or chips that might be found in a spent cutting fluid or from excesses in biochemical oxygen demand (BOD), oil content (FOG), nitrates, or phosphates that cutting fluids typically feature. By considering the portion of the cutting fluid life cycle after final use at the machine tool, this work considers simple, quantifiable metrics that might be used to compare fluids based on their impact on industrial wastewater pre-treatments and publicly owned treatment works (POTWs). The discussion begins with definitions of various environmental issues associated with cutting fluid disposal. Subsequently, a three component matrix is developed that can serve as a metric to compare alternative cutting fluids on the basis of the cost of disposal and legally defined hazards due to fluid chemistry and workpiece residuals found in cutting fluid wastes.
Process Design of Resin Transfer Molding With Computer Simulation
Authors: Zhang Chuck , Jiang Shunliang , Wang Ben , Han Kerang 
Published: January 2022

Abstract
Resin transfer molding is one of the most common fabrication methods for composite materials. It is attractive due to its high volume, high performance, and low cost manufacturing of polymer composites. In this process, a dry preform of reinforcing fibers is placed inside a closed mold; then the resin is injected into the mold cavity. The composite part can be removed from the mold after the resin cures. This paper surveys current issues in the resin transfer molding process and focuses on mold filling and simulation. The Control Volume Finite Element Method is applied to simulate the process. The 2-D and 3-D computational methods are presented. The simulation program was developed with C language by the authors. The 2-D and 3-D models were integrated in the program. In real applications, the 2-D elements and 3-D elements can be applied simultaneously according to the specific requirements. MSC/PATRAN 3 software (MacNeal-Schwendler Corporation) was used to generate the finite element mesh and display the results. Some case studies are conducted to demonstrate the application of the computer simulation to RTM process design.
A Constant Engagement Offset for 2-1/2 D Tool Path Generation
Authors: Stori James A. , Wright Paul K. 
Published: January 2022

Abstract
Contour-parallel and direction-parallel machining strategies typically result in widely varying cutter engagements, excessive plunging and slotting, and sharp velocity discontinuities. In this paper, a new offset is introduced which maintains a constant cutter engagement throughout. By incorporating such an offset into spiraling tool paths, constant chip geometry can be achieved for the majority of the material removal operation. An algorithm for constant engagement tool path generation for convex geometries is developed, and experimental results are presented which demonstrate greatly reduced force variations while cornering.
Nonlinear System Identification Using Lumped Parameter Models With Embedded Feedforward Neural Networks
Authors: Fan Yimin , Li C. James 
Published: January 2022

Abstract
This paper describes a new methodology to identify multi-degree-of-freedom nonlinear systems from the system’s operating data. The methodology includes a new nonlinear model architecture which embeds feedforward neural networks to represent unknown nonlinearities in a lumped parameter model, and a learning algorithm to train the embedded neural networks as well as the other model parameters to obtain model fidelity. Three simulated and experimental examples are used to validate the proposed methodology.
New Concepts on Multi-Sensor Monitoring for Reconfigurable Machining Systems
Authors: Kannatey-Asibu Elijah 
Published: January 2022

Abstract
Effective monitoring of a manufacturing process is essential for ensuring product quality. This paper outlines some basic concepts that will form the fundamental building blocks for selecting an appropriate monitoring system for any given machining system. Presented are the concepts of Fault, Sensor, Signal Processing, and Computing Spaces, and their generic characteristics. A mapping theory that should enable suitable sensors, signal processing algorithms, and computer hardware and software to be selected for a given machining system is discussed. Such a fundamental theory should facilitate development of monitoring systems for reconfigurable machining systems.
Detection, Modelling, and Compensation of Geometric Errors in Coordinate Measuring Machines
Authors: Barakat Nael A. , Elbestawi Mohamed A. 
Published: January 2022

Abstract
A rapid and inexpensive approach is proposed for identifying the existence of geometric and kinematic errors in a Coordinate Measuring Machine (CMM) by means of a circular profile measurement. The proposed approach is applied to an existing CMM where test results are compared to simulation results and errors are identified. Further, a method to improve the CMM performance by error compensation is explained. This method consists of the general and systematic kinematic and geometric error modelling of a CMM for a reference temperature, in addition to the development of a compensation strategy to correct these errors. To verify the rapid error identification approach proposed above and to calculate the error model coefficients for the CMM under investigation, individual errors of the CMM are measured by laser interferometry. The resulting error model is employed directly in the compensation for the CMM errors. Performance improvement of this CMM is presented through measurement of its work tolerance before and after compensation, in accordance with the ASME standards for CMM performance evaluation.
Analysis of the Runout Effect on Hole Quality in Drilling
Authors: Chiou Richard Y. , Wu Kun 
Published: January 2022

Abstract
This paper describes an experimental study of the mechanism of drilling runout and its influence on hole quality. This approach considered the effects of the drilling runout on the hole quality features under various cutting conditions. The drilling runout model was developed as a flexible cantilever beam with a tilt offset. A series of drilling experiments was performed to investigate the drilling runout effect on the hole quality. Standard twist drills were used to drill aluminum workpieces. The drilled hole quality was measured by a Coordinate Measuring Machine (CMM). It showed that the drilling runout has a significant effect on hole quality.
Kinematics Performance Analysis of a Parallell-Chain Hexapod Machine
Authors: Song Jing , Mou Jong-I , King Calvin 
Published: January 2022

Abstract
Inverse and forward kinematic models were derived to analyze the performance of a parallel-chain hexapod machine in this paper. Analytical models were constructed for both ideal and real structures. Performance assessment and enhancement algorithms were developed to determine the strut lengths for both ideal and real structures. The strut lengths determined from both cases can be used to analyze the effect of structural imperfections on machine performance. In an open-architecture control environment, strut length errors can be fed back to the controller to compensate for the displacement errors and thus improve the machine’s accuracy in production.
Comparison of First-Order Shear and Plane Strain Assumptions in Warpage of Simply Supported Printed Wiring Boards
Authors: Polsky Yarom , Ume I. Charles 
Published: January 2022

Abstract
The influence of transverse shear strain in the lamination theory modeling of Printed Wiring Board (PWB) deflection due to support conditions was examined. The in-plane mechanical properties of the core materials of a commercial PWB were measured as a function of temperature. Classical laminated plate theory and first-order shear deformation theory solutions for the out-of-plane deflection of a bare board configuration with two opposite edges simply supported and the remaining edges free were obtained. The weight of the board was approximated as a distributed transverse load. The effect of material property decrease with temperature and FR-4 layer thickness were examined to compare first-order shear and plane strain assumptions for the predicted warpage.
Challenges in Slicing Large Diameter Silicon Wafers Using Slurry Wiresaw
Authors: Chandra Mohan , Leyvraz Philippe , Talbott Jon A. , Gupta Kedar P. , Kao Imin , Prasad Vish 
Published: January 2022

Abstract
This paper describes the challenges present in slicing large diameter silicon ingots using the multiple slurry wiresaw or commonly known as the wiresaw. The wiresaw uses a web of wires moving at a fast speed with a suitable abrasive suspended in a media dropped over the wires. The silicon ingot is lowered on to the web from top down and the cutting action is achieved by the abrasive particles rolling and indenting on the ingot thus removing material. While the cutting mechanism itself is fairly well understood, to achieve the similar surface finish and quality compared to smaller diameter ingots, the cutting parameters of large diameter ingots is not so straightforward. There are many parameters which have to be taken into account which normally would have been neglected or thought insignificant in the case of smaller ingots. We will discuss the various parameters that are affected while slicing small diameter ingots (typically 100 mm) as well as larger diameters (typically 300 mm). Results of experimental tests using commercial wiresaws for slicing these ingots are given to show the effect of wire speed, table speed, the nature of the slurry and other parameters. We also will show how such effects can be described in an analytical fashion by models that have been developed to demonstrate such cutting mechanism.
Current Status of 300 mm Silicon Wafer Characterization
Authors: Messina Troy , Au Chi , Shih Steven , Yang Zach , Goodall Randy , Huff Howard 
Published: January 2022

Abstract
Characterization data for polished 300mm silicon wafers has been obtained, including wafer supplier process and reclaim capability, flatness, particles, interstitial oxygen, metrology tool availability, and tool contamination. Silicon supplier-I300I correlation studies are also detailed.
Technology and System Challenges for 300 mm Metal and Polysilicon Plasma Etch
Authors: Papanu James , Loewenhardt Peter , Olson Dale , Kholodenko Arnold 
Published: January 2022

Abstract
The development of 300mm metal and polysilicon plasma etch systems presents numerous technical challenges. The main efforts can be delineated as mainframe and integration, chamber development, and process characterization and development. With respect to system mainframe and integration, we discuss wafer handling in detail. Discussion of the chamber design effort includes decoupled plasma source development, the electrostatic wafer chuck, and gas feed and distribution as guided by the use of fluid flow simulation. Process and hardware performance data are presented as they illustrate design success.
Performance Prediction of Elastomeric Gasket Materials by Compression Stress Relaxation
Authors: Pannikottu Abraham , Samples Robert , Sadon Stanley J. 
Published: January 2022

Abstract
In the automotive industry, the most widely used technique to predict the sealing capacity of an elastomeric gasket material is based on compression set data which is obtained after short term aging in air or reference fluids. Compression set measures the percentage of permanent deformation after the removal of the applied strain. This is an indirect measure of the sealing capacity and it can easily be misleading as a predictor of the sealing performance of gasket materials. Recent increases in service temperature requirements along with use of “SG” grade motor oils have created the need for a better means of assessing the high temperature, long term performance of elastomeric materials used in automobile engine gaskets. This paper reports Compression Stress Relaxation measurements on a variety of gasket materials using the Wykeham-Farrance Compression Stress Relaxation tester. This study also examines the effect of cycling heating and cooling on the retention of sealing force of gasket materials and includes the cumulative effect of exposure of the gasket material to motor oils and ASTM #2 oil at 125°C up to 1008 hours.