bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of Computational Fluid Dynamics (CFD) in Selective Catalytic Reduction System Ductwork Design
Authors: Wilhite David C. 
Published: January 2022

Abstract
A selective catalytic reduction (SCR) system serving a mixture of two different exhaust gas streams is considered. The exhaust gases are petroleum combustion residues and contain high levels of toxic nitrogen oxides (NOx). The SCR system is used to minimize the hazardous content of the two exhaust streams to meet U.S. national standards.
The SCR system injects ammonia into a mixture of the two NOx-laden exhaust streams, which then pass through a catalyst, where a chemical reaction reduces the NOx to harmless water and nitrogen. The system operates most efficiently within specified gas temperature and velocity ranges.
This paper discusses the use of computational fluid dynamics (CFD) to design a ductwork geometry upstream of the SCR system that results in optimum performance. Various geometries are considered based upon physical space restrictions and operating conditions. The improved duct system results in the desired temperature and velocity ranges at the catalyst face while keeping the total application pressure drop below a preset value.
Analysis of Manufacturing Machinery Effectiveness for Surface Mount Lines
Authors: Yang Yung-Chyuan , Ling Frederick F. 
Published: January 2022

Abstract
This research is concerned with the examination of operational and maintenance data of six electronic manufacturing lines; and the evaluation of the overall equipment effectiveness of these lines at an electronic manufacturing company located in Austin, Texas. The underlying purpose was to help plan the adoption of total productive maintenance (TPM) and to help the company gain competitive advantage by optimizing machine effectiveness.
The overall equipment effectiveness of these six lines, consisting of one line with machines made by Manufacturer A, one line with machines made by Manufacturer B, and four lines with mixtures of machines made by both of the manufacturers, are all below fifty percent. The result reveals the need to reexamine the traditional maintenance strategies. This research also investigates possible causes for the aforementioned level of overall equipment effectiveness.
Application of Shannon’s Communication Theory to Degradation Assessment of Systems
Authors: Bryant Michael David 
Published: January 2022

Abstract
An analogy is made between a machine component (or system) and a communications channel. During operation, information is sent as a signal over a communications channel from transmitter to receiver. The signal over the channel is altered by limited dynamic bandwidth, nonlinearities and noise. The goal is for the receiver to extract and reproduce the message, despite distortions and noise. Design of communications systems is aided by powerful theorems of Shannon (1949), which establish minimum signal to noise ratios for error free transmission.
A machine component (or system) accepts a “signal” from an upstream component, by its function alters that signal, and then passes the “signal” on to the next downstream component. In the analogy of this article, a machine is a communications channel. When operating properly, the “signal” from an upstream component is “received” by a downstream component. Faults in the machine which disrupt functionality alter the “signal”. Faults will be viewed as agents that alter system parameters or contaminate the signal with “noise”. Unless the signal to noise ratio is kept sufficiently high, downstream components cannot “resolve” the “signal message” error free, and the machine malfunctions.
In this article, Shannon’s theorem’s will be applied to machinery to establish performance limits, and develop a failure criteria to assess functionality of new or degraded machinery. With these, operational condition of machinery and maintenance needs can be predicted.
Locator and Sensor Placement for Automated Coordinate Checking Fixtures
Authors: Wang Yu (Michael) , Nagarkar Sanjeev R. 
Published: January 2022

Abstract
This article proposes a systematic method for the optimal design of sensor locations for an automated Coordinate Checking Fixture (CCF). The fixture can be employed for making at-machine assessments of the dimensional accuracy of manufactured components. Coordinate measurements obtained by the sensors built into the fixture can be utilized in estimating geometric parameters of a manufactured part. Two important issues that arise in the design of a CCF are the optimal number of sensors to be used and the best locations for each sensor. The proposed method uses statistical analyses of the Fisher information matrix and the prediction matrix to obtain an optimal set of sensors from an initial candidate set. Sensors are placed at locations that maximize the determinant of the Fisher information matrix for best parameter estimation, while the sensor of the least contribution to the measurement objective is iteratively eliminated. With the benefit of physical insight, the design procedure results in a balanced decision for the optimal placement of sensors. The developed method also addresses the problem of selection of part locators for part localization in the CCF. An example is provided for illustration of the developed procedure.
A Control System for Microwave Processing of Materials
Authors: Groombridge Paul , Siores Elias , Oloyede Adekunle 
Published: January 2022

Abstract
This paper discusses a control system for microwave processing of materials. Microwave joining of ceramics and drying of timber are currently industry practices whilst microwave joining of engineering plastics and curing of epoxy adhesives are still being researched. In this study, all materials are processed in rectangular sections of waveguide fed by a magnetron with a maximum output power of 2 kW operating at 2.45 GHz. The most significant problems encountered when processing these materials are: (i) maintaining proper tuning to ensure maximum power transfer, (ii) thermal runaway, where the heating rate proceeds so rapidly that the material burns within a few seconds, and (iii) hot spot development, where localised regions heat up at a faster rate than adjacent regions. A computerised automated control system has been developed to alleviate these processing problems and has been successfully employed in joining a range of ceramics and engineering plastics, curing epoxy adhesives and drying wood. Results of preliminary tests obtained using the developed prototype are presented.
A Total Cost Comparison of Alternative Tolerancing Formulae
Authors: Graves Spencer B. 
Published: January 2022

Abstract
An important part of many engineering design projects is to specify the amount of variability permitted in critical characteristics of materials, components, and assembly. Different formulae have been suggested for relating input and output specifications. This article reviews the four basic tolerancing formulae that have appeared in the literature and shows that each solves a slightly different problem. In particular, optimal tolerances are based on costs and the probability distributions of input characteristics. Examples of alternative cost-distribution models are provided that (a) make each of the four basic formulae optimal, and (b) make optimal a solution not related to any of these formulae. This establishes that optimal tolerancing is influenced by issues not explicitly considered in the traditional debate over worst-case vs. statistical tolerancing.
Geometrical and Thermal Modeling for Design and Control of Material Deposition Processes
Authors: Kwak Yong-Min , Doumanidis Charalabos 
Published: January 2022

Abstract
In thermal solid freeform fabrication of layered products, simultaneous quality assurance of the part geometry and material structure requires concurrent design of the process conditions with the product features. For a heat transfer analysis yielding the material structure, an analytical, distributed-parameter quasi-linear thermal model is developed and tested in scan welding. This is based on Green’s field, identified in-process by infrared temperature sensing to reflect thermal nonlinearities. Similarly, a mass transfer model of the layer surface geometry is established on an analogous concept of the material deposition field, approximated by an ellipsoidal shape and identified in-process by Laser 3D scanning of the part topology in fused deposition modeling tests. The invertibility and computational efficiency of both models provide a basis for design of adaptive feedback control strategies for the thermogeometrical characteristics of rapid prototypes.
What Layered Manufacturing Can and Cannot Do for Rapid Production Tooling
Authors: Feng Chang-Xue (Jack) 
Published: January 2022

Abstract
Although the initial and primary use of layered manufacturing is rapid prototyping, demands of applying it to rapid tooling is growing dramatically in recent years, and using it to rapid tooling is making more and more sense in terms of saving more time and more money. There are different ways of applying layered manufacturing technology to rapid tooling, such as direct and indirect tooling, hard and soft tooling, using machines from different vendors, and applying to sand casting, investment casting, die casting, injection molding, etc. Furthermore, what accuracy and surface roughness can be provided to production tooling is another major consideration in rapid tooling. As a result, there are many challenges and research opportunities, in addition to many successful cases. Consequently, what layered manufacturing can and cannot do for rapid production tooling will be the focus of this paper.
A Framework on Design for Machining Operations
Authors: Xu Xun W. , Kong Helen 
Published: January 2022

Abstract
Given the fact that current technology has created islands of automation, lack of integration is a major obstacle in the widespread use of CAD/CAM in routine engineering work. This paper presents a case study of design for manufacturing. Design features in a CAD/CAM package have been investigated. Machining features as well as the cutting tools which can be used to produce the machining features are discussed and categorised. Feature mapping is then performed which establishes the links between design features and machining features, and between machining features and cutting tools. As a result, manufacturing information can be readily available at the design stage.
Machine Fault Diagnosis Through a Recursive Optimal Pairwise Linear Discriminant Function Method
Authors: Gu Shuxin , Ni Jun , Yuan Jingxia , Lee Jay 
Published: January 2022

Abstract
A Recursive Optimal Pairwise Linear Discriminant Function (ROPLDF) method based on pattern recognition theory is developed for multiple class fault diagnosis. This approach does not need a priori failure probabilistic knowledge. Optimal pairwise linear discriminant function (OPLDF) is implemented to enhance the performance of the classification, and a recursive method is developed to allow the on-line updating of the coefficients of the OPLDF. Comparison results show that the proposed approach has better performance than other conventional approaches, such as the multiple linear discriminant function method and the feedforward neural network method. A tapping experimental result indicates that the proposed multiple class classification method is effective for practical use. The success rate of this approach for the tapping process condition diagnosis could be 100% with a trained diagnostic model.
Intelligent Decision Making Based on On-Line Non Contact Measurement During Machining Process
Authors: Campana Claudio , Shetty Devdas 
Published: January 2022

Abstract
This paper presents an experimental approach for intelligent monitoring of a Computer Controlled Machining Process. The article reviews the ongoing development in the area of open architecture control for machine tools. This is followed by presentation of the hardware and software scheme adopted to implement on-line inspection procedures. Force overload and vibration in a machining operation can affect dimensional accuracy and surface finish of the workpiece. As such, it is essential to inspect such parameters as surface roughness and geometrical data in an on-line fashion. The surface roughness data is obtained using a new laser based procedure where as geometrical data is obtained using a specially designed optical digitizer. Information from these sensors are used in a rule-based algorithm that provide the appropriate adaptive control of feed rate and spindle speed applied to the machining operation. The supervisory decision making strategy ensures the application of the correct process adjustment so as to optimize the entire machining process.
Force Modeling for Cup Wheel Surface Grinding
Authors: Hekman Keith A. , Liang Steven Y. 
Published: January 2022

Abstract
This paper describes the development of a model for the forces in surface grinding with a cup wheel. The model incorporates the considerations of material removal from the front end of the wheel, the velocity differential between the wheel and part, the material removal from the bottom contact surface of the wheel, to deflection of wheel, and the wheel loading due to buildup. A series of grinding tests were performed with square workpiece and circular workpiece containing a center hole to provide a variety of depths of cut hence a distinct force profile. Experimental measurement of forces is presented in comparison to the model prediction. Statistical significance on the variations with model parameters has been presented on the basis of modeling error analysis.
Some Approaches for Modeling and Analysis of a Parallel Mechanism With Stewart Platform Architecture
Authors: De Sapio Vincent 
Published: January 2022

Abstract
Parallel mechanisms represent a family of devices based on a closed kinematic architecture. This is in contrast to serial mechanisms, which are comprised of a chain-like series of joints and links in an open kinematic architecture. The closed architecture of parallel mechanisms offers certain benefits and disadvantages (stiffness versus dexterity, etc.). A particular subset of parallel mechanisms is known as Stewart platforms (or hexapods). The classic Stewart platform is based on a set of six independently actuated struts. The struts translate through sphere joints which reside on a stationary platform. Each strut terminates at a ball joint residing on a mobile tool platform. All joints allow passive rotation. The effect of this kinematic architecture is that the tool platform can be controlled to move in six axes. This report addresses some analytic approaches for modeling and characterizing these devices. These approaches cover inverse and forward kinematics, Jacobian evaluation, path execution, workspace envelope modeling, tool velocity characterization, and structural stiffness. A characterization is also made of a hybrid parallel-serial architecture consisting of a Stewart platform and a two-axis serial tool head. Numerical algorithms are also provided.
Determination of Number of Independent Parameters for the Self-Calibration of Parallel-Link Mechanisms
Authors: Zhuang Hanqi , Liu Lixin 
Published: January 2022

Abstract
Self-calibration can be a desirable feature for an intelligent machine such as a computer controlled numerical machine tool that must function outside of controlled laboratory conditions. This is because it is inevitable that variations in the kinematic model arise from imperfections in the manufacturing process and changes of environment conditions. Self-calibration facilitates online compensation of errors induced by loading, thermal and other nongeometric errors.
This paper focuses the determination of the maximum number of independent kinematic parameters of a parallel-link mechanism for system self-calibration. Under the assumption of ideal joints and links, a method for obtaining this number is given. A number of examples is given to illustrate the applicability of the proposed method. The result can also be extended to tackle conventional calibration tasks.
Effect of Layering of Joint and Beam on Damping Capacity in Machine Tool Structure
Authors: Purohit Kamlesh , Sharma C. S. 
Published: January 2022

Abstract
In this paper a comparative study of damping capacity offered by individual and combination of three methods i.e. (i) Unconstrained (free) layering (ii) Constrained (sandwich) layering and (iii) Joint interface layering has been presented. The joint interface layering has been found to be the most effective way of applied damping treatment, which not only provides reasonable high loss factor but is also simple and easy to incorporate in any existing machine tool structure.
Some Aspects of the Thermal Performance of a Tape Ball Grid Array (TBGA) Package
Authors: Sathe Sanjeev B. , Sammakia Bahgat G. 
Published: January 2022

Abstract
This paper deals with the thermal management of a TBGA chip carrier package. In TBGA packages the back side of the chip is available for heat sink or heat spreader (cover plate) attach. By attaching a heat sink directly to the chip and using a thin layer of high thermal conductivity adhesive, a very low internal thermal resistance can be achieved. The package is attached to an organic card and placed vertically in a channel. A three dimensional conjugate heat transfer model is used, accounting for conduction and radiation in the package and card and convection in the surrounding air. A simplified turbulence model is developed to predict temperatures in the low Re turbulence regime. A parametric study is performed to evaluate the effects of card design, air velocities, interconnect thermal conductivities and thermal radiation on the chip junction temperatures. An experimental study was also conducted to verify the model. Even though the geometry is highly complex due to the multi-layer construction of the module and the card, agreement between the model and the experimental measurements is excellent. It was shown that radiation heat transfer can be an equally significant mode as convection in the natural convection regime.
Three-Dimensional Simulation of Microchip Encapsulation Processes
Authors: Han Ruihua , Gupta Mahesh 
Published: January 2022

Abstract
A three-dimensional simulation of moving boundaries in an inertia-free, incompressible flow is presented. A control volume approach with a fixed finite element mesh is used to predict the fluid front advancement. Predicted fluid front advancement and pressure variation in a flow domain similar to the mold used for microchip encapsulation are compared with the corresponding experimental results.
Three-Dimensional Finite Element Modeling of Flip Chip Packages Under Thermal Loading
Authors: Yao Qizhou , Qu Jianmin 
Published: January 2022

Abstract
In this study, both two-dimensional and three-dimensional finite element analyses were used to study the stress distribution in and deflection of the flip chip assembly under thermal loading. It is found that the three-dimensional results compared favorably with experimental measurements, while the two-dimensional results consistently overestimate both stresses and deflection. Among the two-dimensional models, plane stress assumption seems to yield results closer to the full three-dimensional predictions. Furthermore, three-dimensional models were used to investigate the effect of printed wiring board size on the overall deflection of the flip-chip assembly. This size effect of the printed wiring board has significant implications on the design of multi-chip modules. The results indicate that a square array placement pattern is preferable to a staggered array for multiple chip modules in order to reduce mechanical interaction between chips. For square arrays, such mechanical interaction between chips can be neglected when the minimum distance between adjacent chips is more than 2 times the chip size.
Thermo-Solutal Issues in Very Large Diameter Silicon Crystal Growth
Authors: Zhang T. , Wang G.-X. , Ladeinde F. , Prasad V. 
Published: January 2022

Abstract
Although 200 mm diameter wafers presently dominate the semiconductor market, 300 mm wafers are expected to be commonly used at the turn of the century. Larger wafer diameter is needed in order to increase the chip yield due to increase in chip size due to higher integration and performance of both memory (DRAM) and microprocessor (MPU) devices. mm diameter single crystals. As the crystal diameter is increased from 200 mm to 300 mm or larger, the size of the melt increases significantly leading to much more complex melt dynamics. Turbulent melt flow phenomena make the predictions and control of growth conditions very difficult. Understanding of the heat and mass transport in large melt systems is therefore critical to the growth and control of high-quality, large-diameter silicon single crystals. This paper examines various thermal-solutal issues related to Czochralski growth of 300 mm silicon crystals such as turbulence in the melt, heat transfer, oxygen transport and control, and the recent progress is reviewed.
Development of a Knowledge-Based 3D CAD System for Plastic Injection Mold Design
Authors: Lee K. S. , Zhang Y. F. , Fuh J. Y. H. , Ye X. G. , Li Z. , Nee A. Y. C. 
Published: January 2022

Abstract
This paper discusses the methodology in developing a 3D CAD system for injection mold. There are hundreds of parts in a set of mold, these parts can be classified and managed by an assembly method. The assembly tree structure can be looked upon as a reverse tree, each branch represents a sub-assembly tree structure, and leaves are part files. The parts are created by parametric geometrical model, parameters are used to control part size. A linkage between geometrical model and part database was built up to load the standard parts automatically. Associations are created among these parts by referring parameters with each other. A version management method is discussed to keep design status and restore to previous design as necessary. Mold design specification functions such as parting, cooling, mold base, insert creation are also provided to designers. A knowledge-based 3D CAD system is currently being used in the local mold design and manufacturing companies.
An Integrated Computer-Aided Modular Fixture Design System for Interference Free Design
Authors: Kow T. S. , Kumar A. Senthil , Fuh J. Y. H. 
Published: January 2022

Abstract
In the development of an automated fixture design system, issues such as automated points and elements generation, and interference free design are of great concern to achieve a quality design in a shorter time. The automation of the fixture design process is of great importance in view of the current trend towards an automated manufacturing environment. This paper describes a CAD-based methodology in developing a modular fixture design system using Unigraphics (UG) solid modeler, integrated with a modular fixture element database based on a hole-based IMAO modular fixturing system. Parametric modeling technique has been applied to construct the database. An integrated methodology is introduced to the system where the functions of interactive, semi-automated and automated fixture design system are combined collaboratively in single environment. This provides the flexibility and functionalities in making the design process more efficient. The interactive fixture design module facilitates the designer to select the fixturing faces, points and elements in building a fixture. Semi-automated and automated fixture design modules are built by transforming the designers’ experience and knowledge into rules and algorithms so as to automate the selection of fixturing points and elements. More importantly, the system aims at producing a tool collision-free fixture design using its machining interference detection module based on cutter swept volume approach.