bluuebunny/crossref_metadata_2025 huggingface dataset:
Chip Geometry Based Modeling of Dynamic Tool Force/Motion Error Relationship in Diamond Turning
Authors: Ro Paul I. , Abler Jeffrey A.
Published: December 2021

This paper presents a comprehensive model of the dynamic tool force / motion error relationship for diamond turning. A key to a successful control of diamond turning process to achieve the theoretical finish lies in understanding the relationship that governs the generation of dynamic tool motion errors due to the variation in tool force. However, this relationship is neither well established nor simple, and is dependent upon material properties, various machining parameters, and the wear condition of the tool. In Part I, a model for this relationship is developed based upon the variations in the geometry of the tool and workpiece interaction resulting from their dynamic motion errors. The model is obtained as a first order variation from a static relationship, and consists of stiffness and damping terms. The total stiffness terms are characterized by variations in the chip geometry due to dynamic motion errors along the thrust direction. The thrust component of this model is then verified experimentally using the measurements of motion errors while simultaneously measuring the dynamic tool forces.
Assessment of Flow and Cure Monitoring Using Direct Current and Alternating Current Sensing in Vacuum Assisted Resin Transfer Molding
Authors: Jadhav Nitesh C. , Vaidya Uday K. , Hosur Mahesh V. , Gillespie John W. , Fink Bruce K.
Published: December 2021

Vacuum Assisted Resin Transfer Molding (VARTM) is an emerging manufacturing technique that holds promise as an affordable alternative to traditional autoclave molding and automated fiber placement for producing large scale structural parts. In VARTM, the fibrous preform is laid on a single sided tool, which is then bagged along with the infusion and vacuum lines. The resin is then infused through the preform, which causes simultaneous wetting in its in-plane and transverse directions. An effective sensing technique is essential so that comprehensive information pertaining to the wetting of the preform, arrival of resin at various locations, cure gradients associated with thickness and presence of dry spots may be monitored. In the current work, direct current and alternating current sensing/monitoring techniques were adopted for developing a systematic understanding of resin position and cure on plain weave S2-Glass preforms with Dow Derakane vinyl ester VE 411-350, Shell EPON RSL 2704/2705 and Si-AN epoxy as the matrix systems. The SMARTweave DC sensing system was utilized to conduct parametric studies a) to compare the flow and cure of resin through the stitched and non-stitched preforms, b) influence of sensor positioning, i.e., top, middle and bottom layers, c) influence of positioning of the process accessories, i.e., resin infusion point and vacuum point on the composite panel. The SMARTweave system was found to be sensitive to all the parametric variations introduced in the study. Furthermore, the results obtained from the SMARTweave system were compared to the cure monitored from embedded IDEX dielectric sensors. The results indicate that SMARTweave sensing was a viable alternative to obtaining resin position and cure, and more superior in terms of obtaining global information in contrast to the localized dielectric sensing approach.
Adaptive Influence Coefficient Control of Single-Plane Active Balancing Systems for Rotating Machinery
Authors: Dyer Stephen W. , Ni Jun
Published: December 2021

Rotating unbalance is a costly source of harmful vibration affecting a wide variety of applications such as high-speed machine tools and turbomachinery. Active balancing technology allows adjustment of a machine’s balance state while conditions change as the machine continues to operate. An adaptive control law for single-plane active balancing is presented here for control of steady-state rotation-synchronous vibration. The adaptive control method, based on the well known “influence coefficient” approach, requires no a priori modeling or estimation of plant dynamics. A control “gain” parameter is introduced and shown to enhance stability robustness of the non-adaptive portion of the control law. A recursive on-line system identification method is presented that uses exponential weighted averaging to mitigate the effects of measurement noise and system nonlinearities. Experimental results establish the efficacy of the adaptive control system even in the face of certain nonlinear and time-varying rotordynamic systems.
Study on Acoustic Emission During High-Speed Grinding and Ultraprecision Grinding of Advanced Ceramics
Authors: Gowri S. , Ngoi Bryan K. A. , Ramesh K.
Published: December 2021

The process of grinding produces characteristic acoustic emissions (AE) and the signals of AE could be used as ‘condition monitoring’ tool to understand the phenomenon involved in material removal. It has been observed that high-speed grinding of the ceramics improved machining productivity without deteriorating the surface quality of the ceramics, which is not common in the case of metals. Residual stress analysis on the machined ceramics indicated that built-in residual stress might have reduced the crack-formation. Critical grinding conditions limiting the formation of cracks on the ceramics were identified. The trend in AErms signals could be correlated to the grinding force and the grinding conditions. In case of ultraprecision machining, the ductile regime grinding of the ceramics was found out in terms of feed and depth of grinding with grinding velocity. Analysis with the SEM of machined ceramic surfaces and the AErms could reveal the occurrence of ductile regime grinding and also the transition of ductile to conventional brittle mode of material removal during grinding.
Development of the TIARA Hexapod: A Machine Tool Based on Parallel Kinematic Structures
Authors: Centea Dan N. , Lacheray Herve , Audren Frederic , Teltz Richard , Elbestawi Mohamed A.
Published: December 2021

The paper focuses on the TIARA Hexapod — a parallel kinematic machine tool that is being developed at McMaster University. The design uses fixed length struts, and an inclined layout for the motion axes that results in the mechanism resembling a ‘tiara’. In addition to the novelty of the design, these characteristics have several advantages from both a performance and economic perspective. The paper presents an overview of the development program for this machine tool, discussing issues related to design, modelling, inverse and forward kinematics, workspace, and dynamics analysis. Later sections of the paper detail the kinematic and dynamic models developed for the TIARA machine tool, and demonstrate their use for workspace analysis and the specification of actuator requirements.
Closed-Loop Shape Control of the Stretch Forming Process Over a Reconfigurable Tool: Precision Airframe Skin Fabrication
Authors: Valjavec Marko , Hardt David E.
Published: December 2021

The accuracy of stretch formed sheet metal parts in the aerospace industry depends heavily on tool designer and machine operator expertise. In addition, fixed-configuration facilities and rigid tools result in long lead times, high manufacturing costs and insufficient product quality. In response to this, a methodology combining an adaptive closed-loop shape control algorithm and a reconfigurable forming tool has been developed and implemented for stretch forming. This method is based on empirical estimation of the process characteristics using a “Deformation Transfer Function” and is capable of rapidly generating a tool shape that produces the desired final part shape, even when significant process uncertainties exist. The same control system is also used to compensate for shape distortions caused by the downstream manufacturing processes of chemical milling and trimming. Experiments involving various compound curvature skins are presented that validate the effectiveness of this methodology in reducing the shape errors below the forming system error threshold in just one or two closed-loop forming trials regardless of skin shape.
Flexible Forming of Sheet Metal Using Plasma Arc
Authors: Chen YiWei , Li PengJiu , Male Alan T. , Zhang YuMing
Published: December 2021

Conventional precision forming of sheet metal requires the use of mechanical tools. However, during product development, different tools may be required to form various shapes, thus requiring significant tool cost and lead time. If a rapid prototyping process were available such that the required shapes can be formed without the need for hard tools, the potential reduction in product development cost and lead time could be quite significant. Moreover, such a process could be used for very short run production where it would be uneconomical to amortize tooling cost over a small number of manufactured pieces. To explore the potential for flexible forming without tools, various researchers have used laser beams as a heat source to form sheet metals, with a significant measure of success. To investigate the use of a more economical and potentially safer heat source, the authors recently established an experimental system to investigate the feasibility of forming sheet metals using a non-transferred arc plasma as the energy beam and CO2 as the cooling jet. Several samples have been formed using the developed experimental system. Experiments have shown that the forming direction, either toward or away from the plasma arc beam, can be completely controlled to allow the formation of complex shapes. It is believed that this provides the basis for a new rapid prototyping process for the forming of sheet metal components.
Dynamic Modeling of an Indexing Valve Plate Pump
Authors: Cho J. , Zhang X. , Nair S. S. , Manring N. D.
Published: December 2021

The swash-plate in a variable displacement pump experiences very large forces and moments that try to dislocate its position and therefore a large device is required for adequate control. In this paper, the dynamics of an alternative pump design using an indexing valve plate to position the swash-plate are reported. The indexing valve plate design is aimed at controlling the pressure transition for a piston, which is moving from a high-pressure port to a low-pressure port and back. In this paper, the governing equations for the pump are derived and the detailed open-loop, which is necessary for understanding the overall dynamic characteristics of the pump, is reported. Also, linear and nonlinear modeling approaches for the system are compared.
Thermal Considerations in Fluid Power Systems Modeling
Authors: Fernandez Raul , Woods Robert L.
Published: December 2021

A systematic derivation of fluid capacitance for use in compressible and incompressible fluid power modeling is presented. Equations are stated explicitly for the control volume pressure and temperature states, which include a simple but realistic estimation of heat transfer effects based on a first-order approximation to the chamber wall thermal dynamics. Simulations representative of industrial hydraulic and pneumatic applications are presented, showing the expected fluid pressure and temperature responses for the control volume with various modeling assumptions, and ultimately justifying the use of simplified isothermal relations for hydraulics in general and for many low-pressure servopneumatic applications.
Pneumatically Operated Wheelchair for Step Drive
Authors: Shiraishi Masatake , Sumiya Hideyasu , Aoshima Shinichi
Published: December 2021

A new wheelchair capable of 10 cm-step drive has been developed. It uses pneumatic pumps installed on the rear wheels of the wheelchair. The pneumatic pumps generate pressurized air, which is sent to the reservoir, in proportion to the rear wheel rotation: travel of about 12 m is needed to reach full pressure. The required air is introduced from the reservoir into two driving cylinders, fixed to the front support frames, that lift the front wheels. The lifting operation is performed by handling the braking levers. Our experimental design system shows the feasibility of using pneumatic pumps for this operation.
Nonlinear Feedforward-Plus-PID Control for Electrohydraulic Steering Systems
Authors: Qiu Hongchu , Zhang Qin , Reid John F. , Wu Duqiang
Published: December 2021

This paper presents the development of a nonlinear feedforward-plus-Proportional-Integral-Derivative (FPID) controller for electrohydraulic (E/H) steering on wheel-type tractors. An E/H steering system is a typical nonlinear system with deadband, saturation, asymmetric flow gain, time delay, and other nonlinear behaviors. Conventional PID controllers are incapable of achieving accurate steering control effectively on such nonlinear systems. In this research, an FPID controller was developed for effective and accurate steering control. The feedforward loop in this controller was designed to compensate for the deadband of the E/H system. The PID loop was designed to compensate the tracking error in steering control. A coordinated nonlinear gain function was designed to change the PID loop gain based on the level of the tracking error. This FPID controller has significantly improved the steering accuracy comparing with that from a PID controller. Test results showed that the maximum tracking error in steering angle was less than 0.5° corresponding to a sinusoid steering command of ±5° at the command frequency of 0.1 Hz. The maximum overshoot was less than 12% and the rise time was less than 0.25 s corresponding to a steering command of 5° step input. This FPID controller achieved effective and accurate steering control on agricultural tractor E/H steering systems.
Robust Tolerance Design Considering Process Capability and Quality Loss
Authors: Feng Chang-Xue (Jack) , Balusu Ravi
Published: December 2021

Tolerance design bridges design and manufacturing. Concurrent design of tolerances and manufacturing processes may ensure the manufacturability, reduce the manufacturing and other related costs, decrease the number of fraction nonconforming (or defective rate), and shorten the production lead time. Since process capability indices relate tolerance specifications to manufacturing process capabilities, it is quite natural to apply them to concurrent design of tolerances and processes. As process shifts often exist in a manufacturing process, using Cp does not yield a good estimation of fraction nonconforming. Index Cpk does not precisely measure process shift either, but Cpm does. Therefore, this research compares the applications of Cp, Cpk and Cpm based on a numerical example of non-linear mechanical tolerance synthesis. In addition, the Taguchi quality loss function is used together with the manufacturing cost as the objective function.
An Optimized Production Technology Approach to Design for Throughput
Authors: Billatos Samir B. , Wolffarth Gregg
Published: December 2021

Many manufacturing organizations are losing their competitive position due to a large number of reasons discussed in this paper. To regain a competitive position, organizations must clearly understand their goals. The Goal for a manufacturing organization should be making money now and in the future [1,2]. Producing products, high utilization, keeping people busy, high quality, good customer service, etc., are means to the Goal but not ‘The Goal’ itself. To achieve an organization’s goal, management must turn to OPT. OPT (Optimized Production Technology) is the original and most advanced constraint based advanced planning and scheduling system [3,4]. It is the practical implementation of the Theory of Constraints in the modeling, planning and scheduling of activity based business. OPT has proven its applicability in job shop, repetitive manufacturing and process industries all over the world. Therefore, shop floor issues, such as bottlenecks, setups, lot sizes, priorities, random fluctuations and performance measurements, are treated in great depth. The OPT philosophy incorporates nine rules which, when followed, can help move the organization towards the goal of making money. Underlying each of the rules is the understanding that effective management of an organization takes a global perspective of all resources and their interrelationship to achieve the goal. These rules coupled with a set of measurements: Throughput, Inventory and Operating Expenses, would lead any manufacturing organization to fulfilling the goal. Since few literatures have covered the general application of these measures, this paper will focus only on Throughput. The paper will discuss the step-by-step implementation procedures that would help industry in designing their systems for throughput.
Competitive Conceptual Design of Engineering Systems
Authors: Bzymek Zbigniew M.
Published: December 2021

This paper discusses design resulting from a unique design competition as an indicator of the verification of scientific design principles as given by Shu Nam 1990. A single enactment of the design problem is used as a case study to illustrate different points of this paper. The focus of the paper is on the creative aspect of idea generation and the checking of subsystems as well as the complete system enactment for function and performance. In an annual design competition the same problem was issued to a number of design teams. The number of teams varied from nine to eighteen in different years and two to three designers were in a team. The design was performed by seniors in mechanical engineering. To generate concepts, Osborn’s method of brain storming was applied. The brain storming was done in the groups of two to three designers. It was applied to the entire system and subsequently to subsystems. After the abstract design was accomplished, prototypes were built and tested. A competition was held in which each design group prototype earned a figure of merit score based on its performance in a performance run. The figure of merit formula used to dtetermine the winner of the competition and race course for performance run were given to the designers at the time they were given the design problem statement. The results were verified by an expert evaluation with Mechanical Engineering faculty members serving as experts. Every prototype was competing with others in the same exact conditions. The results of the design competition provide a unique set of data which may be considered an experiment in design technique. Some concluding remarks concerning design methodology are stated.
Robust Design: Tolerance Design Method
Authors: Yang Hanxiang , Chen Pah I.
Published: December 2021

There are three phases involved in Robust Design — conceptual design, parameter design, and tolerance design. Parameter design aims to specify the variations of the design parameters in order to meet the design requirement, and the tolerance design further specifies the optimized parameters in order to reduce the performance variation near the design target. A robust design requires that tolerance design to be preceded by parameter design.

In this paper, our effort will be focused on presenting an iterative method to perform the tolerance design phase. Two hypothetical examples (whose parameter designs have been completed) will be used to illustrate the tolerance design methodology. The first example involves the design of a pneumatic cylinder whose piston movement can be expressed by a theoretical equation containing five parameters. With the equation, it becomes a simple task for determining the tolerances of the optimized parameters to constrain the design target. The second example involves the production of a agrochemical by mixing two chemicals to achieve a specific yield. A set of test data is available but the equation relating the parameters is not. In this case, we shall adopt the linear regression technique to obtain an experimental equation to represent the test data. Based on this equation, we can proceed to determine the tolerances of different parameters in order to achieve a specific variation of the yield.

The step-by-step procedure outlined in the hypothetical examples demonstrates that this iterative method is a simple and effective way to conduct the tolerance design.
Optimal Shapes of Fully Embedded Channels for Conjugate Cooling
Authors: Fisher T. S. , Torrance K. E.
Published: December 2021

Optimal shapes and geometries are determined for systems involving liquid and gas coolants. The shape of the channel boundary, channel width, and wall thickness are varied to minimize overall thermal resistance under flow constraints involving pressure drop and pump work. The effect of boundary curvature is studied systematically by employing a parameterized boundary shape that spans from rounded rectangles to ellipses to rounded diamonds. The results indicate that increased channel boundary curvature can decrease the optimal distance between channels, and that the optimal boundary shapes of fully embedded channels can be non-rectangular. In particular, elliptic and nearly elliptic shapes are found to produce equivalent optimal thermal performance as rounded rectangular shapes under practical conditions.
Optimization of Twin Screw Compressor With a Software Package
Authors: Xing Ziwen , Peng Xueyuan , Shu Pengcheng , Cui Tiansheng
Published: December 2021

A software package for the design of twin screw compressors is introduced in this paper. Functions of its main program include profile generation, geometrical parameter calculation, performance simulation, dynamic analysis, rotor deflection calculation, and cutter shape calculation. It is shown that the design work of twin screw compressor can be done quickly and precisely with the help of this software package. It is also illustrated how to obtain an optimum design by making use of the package.
ABSIM: Modular Simulation of Advanced Absorption Systems
Authors: Grossman Gershon , Zaltash Abdi
Published: December 2021

The computer code ABSIM has been developed for simulation of absorption systems in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. Based on a user-supplied cycle diagram, working fluid specification and given operating conditions, the program calculates the temperature, flowrate, concentration, pressure and vapor fraction at each state point in the system and the heat duty at each component. The modular structure of the code is based on unit subroutines containing the governing equations for the system’s components. A main program calling these subroutines links the components together according to the cycle diagram. The system of equations for the entire cycle is thus established, and a mathematical solver routine is employed to solve them simultaneously. Property subroutines contained in a separate database serve to provide thermodynamic properties of the working fluids.

The paper describes the current capabilities and recent improvements made to ABSIM along with examples of simulation results for several rather complex cycles, including lithium bromide-water double-, triple- and quadruple-effect cycles and ammonia-water GAX, branched GAX and vapor exchange (VX) cycles.
A New Generalized and Inversed Vapor Pressure Correlation Applied to Experimental/Smoothed Data for Pure Fluids
Authors: Rogdakis E. D.
Published: December 2021

In the present work a new vapor pressure equation is proposed which combines all advantages of the most significant equations, i.e.

• As Wagner equation, it is capable of representing the correct shape of the vapor pressure curve for expanded ranges of the temperature.

• As Antoine equation, it can be inversed expressing boiling point as a function of the pressure.

• As in Lee-Kesler and two reference fluids methods, it has been found a very useful and more accurate correlation in terms of the reduced temperature.

Another advantage of the new equation is its fundamental, single and generalized form for all substances.

Extensive test of the proposed equation using experimental/smoothed data for twenty-two pure fluids indicates that it normally predicts very well the vapor pressure from the critical down to the triple point. (Overall Average Mean and Overall Average Max. Error 0.0526% and 0.1195% respectively).

A predictive method too for the triple point pressure has been developed (Mean Error 1.1553%).
The Effect of Humidity on the Thermodynamic Behaviour of Atmospheric Air
Authors: Kouremenos D. A. , Kakatsios X. K. , Krikkis R. N.
Published: December 2021

The present work considers the thermodynamic behaviour of moist air as a function of the state variables temperature, density and humidity ratio. Moist air is treated as an ideal mixture which is composed of two real gases, air and steam. The state functions of the mixture are expressed using the corresponding explicit relations of the two species from which the three isentropic exponents describing the real gas isentropic change are calculated. Saturated conditions are determined by solving the Vapour Liquid Equilibrium problem for real water. Numerical results show the effect of humidity as well as the effect of pressure on the thermodynamic behaviour of atmospheric air (such as the three isentropic exponents kpρ, kTp, kTρ, the classical isentropic exponent k and the velocity of sound) for a wide range of temperatures and pressures. Furthermore the isentropic change is approximated by explicit relations having mathematical forms similar to those of the ideal gas but with different constants and exponents. The obtained accuracy is remarkable, being better than 0.32%. In this way the isentropic change, of moist air can be computed by simple explicit relations having as independent variable the Mach number and the humidity ratio. The effects of humidity are examined on certain cases of practical interest such as the critical state (M = 1), the impulse function and the mass flow rate.
Combustion Quasi-Two Zone Predictive Model for Dual Fuel Engines
Authors: Abd Alla G. H. , Soliman H. A. , Badr O. A. , Abd Rabbo M. F.
Published: December 2021

A quasi-two zone predictive model developed in the present work for the prediction of the combustion processes in dual fuel engines and some of their performance features. Methane is used as the main fuel while employing a small quantity of liquid fuel (pilot) injected through the conventional diesel fuel system. This model emphasizes the effects of chemical kinetics activity of the premixed gaseous fuel on the combustion performance, while the role of the pilot fuel in the ignition and heat release processes is considered. A detailed chemical kinetic scheme consists of 178 elementary reaction steps and 41 chemical species is employed to describe the oxidation of the gaseous fuel from the start of compression to the end of expansion process. The associated formation and concentrations of exhaust emissions are correspondingly established. This combustion model is able to establish the development of the combustion process with time and the associated important operating parameters such as pressure, temperature, rates of energy release and composition. Predicted values for methane operation show good agreement with corresponding previous experimental values over a range of operating conditions mainly associated with high load operation.
Development of Miller Cycle Gas Engine for Cogeneration
Authors: Tsukida Nobuaki , Okamoto Kazuhisa , Abe Takashi , Takemoto Toru
Published: December 2021

We have developed a 300 kW gas engine cogeneration system for practical use that uses natural gas. Using a gas engine operated under conditions with an excess air ratio λ = 1 that is able to use a three way catalyst to purify the exhaust gases, we were able to achieve high efficiency through the application of the Miller Cycle, as well as a low NOx output. In terms of product specifications, we were able to achieve an electrical efficiency of 34.2% and a heat recovery efficiency of 49.3%, making an overall efficiency of 83.5% as a cogeneration system.
Optimal Capacity Planning of a Brewery’s Energy Supply Plant Using its Simulation Model Based on LabVIEW
Authors: Shiba Takashi , Ito Koichi , Yokoyama Ryohei , Sakashita Shigeru
Published: December 2021

An optimal capacity planning method is proposed for a brewery’s energy supply plant from the viewpoint of long-term economics. The proposed method is composed of two hierarchical stages. At the outer stage, equipment capacities and utility maximum demands of the brewery’s energy supply plant are optimized together with values of control parameters of thermal storage tanks by the sequential linear programming method. At the inner stage, the equipment operation of the plant for given energy demands is simulated on the basis of control rules using LabVIEW. Both two stages are interconnected so as to be compatible with each other. Through a numerical study, it is investigated how equipment capacities, utility maximum demands, and control parameters of thermal storage tanks influence the long-term economics of the plant. From the results, it is ascertained that the long-term economics can be improved using the proposed method.
Investigation and Evaluation of Steam Hammer Occurring During Boiler Blowdown Process
Authors: Park Hyunjae , Richardson Dave , Stansfield Tod , Tompkins Gene , Molvie Peter
Published: December 2021

When a reservoir (vessel) discharges through pipes, and the flow is regulated by a valve(s), a metastable and/or critical flow may occur. The metastable flow may be due to choking of the flow or flashing of the fluid (in the pipe or through the valve). These phenomena are highly transient and involve sudden changes in fluid velocity, leading to large pressure changes which manifest themselves as pressure waves, across which there are discontinuities in pressure and velocity. These relatively strong pressure pulses and waves propagate throughout the system and may damage some of the system components. Pressure waves of this general nature are often called steam (or water) hammer. A major issue in the boiler industry is damage to boiler safety devices due to such phenomena, which sometimes occurs during the boiler blowdown process. The blowdown process is similar to the discharge through pipes and valves as described above. In this paper, a one-dimensional analytical model is developed to predict the intensity of steam hammer in terms of relevant parameters.
Second Law Analysis of Separation Processes of Mixtures
Authors: Çengel Yunus A. , Çerçi Yunus , Wood Byard
Published: December 2021

Mixing and separation processes are commonly encountered in a wide range of industries in practice. Separation processes require a work (more generally, exergy) input, and minimizing this required work input is an important part of the design process of separation plants. The presence of dissimilar molecules in a mixture affect each other, and therefore the influence of composition on the properties must be taken into consideration in any thermodynamic analysis. Below we first analyze the general mixtures and the mixing processes, with particular attention to ideal solutions, and determine the entropy generation and the corresponding exergy destruction. We then consider the reverse process of separation, and determine the minimum (or reversible) work input needed for separation. The results presented can readily be used in the calculation of minimum work input and the determination of the second law efficiency of separation processes.
Thermodynamic Analysis and Optimisation of Mixed Fluid Turbine Power Plants
Authors: Belli M. , Stumbo M. , Vinarova D.
Published: December 2021

This paper discusses the thermodynamics of power cycles where steam or water are mixed with air to improve the performance of stationary gas turbine cycles. A general computer simulation program is presented; several components (compressor, combustor, turbine, recovery boiler, saturator, recuperator, inter-cooler, after-cooler) are modelled obtaining a transfer function between in-coming and out-coming fluids.

Coupled with this simulation program, an optimisation is carried out using a decomposition strategy based on the second law of thermodynamic and a concept for costing the components of the cycles. A large number of decision variables can by optimised with enhanced convergence to an optimum.

As results, a large number of simulations and optimisations are performed for three different plants (STIG, HAT and a cycle with water injection both in the compressor and in the combustor). A wide number of comparisons shows the difference between the cycles and the power level at which each plant gives the lowest exergoeconomic costs.
Total Equivalent Resource Consumption of Residential Heating Systems
Authors: Reistad Gordon M. , Moungkeow Thanat
Published: December 2021

This paper reports on an evaluation of several energy conversion systems utilizing the Total Equivalent Resource Exergy (TERE) method (Zhang and Reistad, 1998). The systems are residential gas furnace and heat pump systems. The TERE method uses exergy as an overall evaluation parameter for energy conversion systems which combines energy and environmental resource (global warming) consumption. The method evaluates the exergy of the fuel, the exergy for the material in the system and the exergy required to recover the total global warming impact caused by CO2 equivalent emissions. This is done for both the energy conversion and production systems. The results illustrate comparisons of the systems for their consumption and their total lifetime impact including global warming.

Results of these comparisons, with the assumptions made, indicate that the high efficiency natural gas furnaces have less lifetime impact (greater efficiency) in satisfying a specified heating load as compared to low efficiency natural gas fueled furnaces. Some very high-efficiency furnaces with large blowers may, however, have greater lifetime impact than units that have moderately high efficiencies and smaller blowers. Relative to the three heat pump systems considered, the high efficiency gas furnaces were evaluated to have less lifetime impact than the air-source and direct-expansion, ground-source heat pumps, but more lifetime impact than the vertical ground-source heat pump. The annualized TERE values of the high efficiency gas furnaces are about 94 GJ compared to the greater than 100 GJ of the first two types of heat pumps. The vertical ground-source heat pump has the lowest annualized TERE value of 88 GJ.

These comparisons should be viewed in light of the following:

• The CO2 recovery exergy assumed here is not a precise value. This recovery exergy does have a major influence on TERE.

• The energy requirement and heat pump performance taken in this evaluation is based on one certain location in the U.S., a Northwest region, and the results do not necessarily apply to other locations and climate patterns.

• The accurate evaluation of scarce information such as weight and material of each component in the energy conversion systems is difficult; the information used in this evaluation is based on estimations.
Comparison of Various Methods to Represent Energy Features of a Total System
Authors: Ishida Masaru , Yamamoto Masashi
Published: December 2021

Comparison of various methods for analyzing characteristic features of a total system is demonstrated. Process flow diagram (PFD) shows streams and main apparatuses schematically. Hence we can imagine system configuration. However, it gives no quantitative information. Energy flow and exergy flow diagrams, respectively, show information about the first law and the second law of thermodynamics. The advantages of these diagrams disappear for a large and complex system.

Then we propose a new diagram, a process flow diagram with process vectors. Base frame of this diagram is the same of the PFD, but information about H and ε of important streams and ΔH and Δε for each change of substances is represented by drawing process vectors. And features of exergy loss are clearly depicted by their combination.
Development of a Simulation Tool for Gas Co-Generation Systems
Authors: Murata Yukimaro , Horizoe Tomohiko , Oka Masahiro
Published: December 2021

Tokyo Gas developed a new simulation tool for gas co-generation systems. We expect that this tool will help us in both developing co-generation components such as absorption chillers to utilize the waste heat of co-generation and making suggestion for optimum co-generation engineering.

This simulation tool is superior to other simulation tools in simulation result accuracy and availability to complicated co-generation systems. It was achieved by new calculation logic and detailed description of features of co-generation components. This simulation tool can evaluate energy consumption and running cost of simulation models for buildings with co-generation systems.

Tokyo Gas has used this simulation tool in development of three new gas absorption chiller heaters with auxiliary waste heat recovery and for energy consumption evaluation of many buildings with co-generation systems, which are so complicated that other simulation tools are not available.
Laser-Based Transient Surface Acceleration of Thermoelastic Layers
Authors: Cetinkaya Cetin , Li Chen , Wu Cunli
Published: December 2021

The effectiveness of traditional surface cleaning methods, such as ultrasonically induced fluid flow, vibrational methods, centrifugal techniques, is limited to particles that require surface acceleration lower than 107m/s2. For sub-micron particles, a higher level surface acceleration is needed. In the current work, based on the generalized dynamic theory of thermoelasticity, a transfer matrix formulation including the second sound effect is developed for a layer. The transfer matrix for axisysmmetric wave propagation in the thermoelastic layer is obtained by adopting integral transforms. The second sound effect is included to eliminate the immediate arrival of thermal waves. A transfer function formulation for calculating the accelerations is developed for transient analysis. In the current work, only the surface acceleration due to transient thermoelastic wave propagation is under investigation.
Effects of Exciting Frequency and Grain Size in Ultrasonic NDE of Concrete
Authors: Ju J. W. , Weng L. , Liu Y.
Published: December 2021

This investigation focuses on experimental study of the effects of the exciting frequency and the grain (aggregate) size upon the ultrasonic P-wave velocity and the wave attenuation characteristics such as the peak-to-peak amplitude and dominant frequency-shift when performing the ultrasonic nondestructive evaluation of concrete. Furthermore, this presentation studies the extent of wave attenuation as influenced by different grain (aggregate) sizes with or without the well-distributed embedded micro-damage under different exciting frequencies. The damage index or damage assessment of concrete is certainly linked to the reduction in the ultrasonic P-wave velocity, the reduction in the peak-to-peak amplitude response, and the increase in frequency-shift through a damaged concrete specimen.

In this study, we cast concrete cylinders with five different aggregate sizes in our laboratory, including some mortar samples without coarse aggregates. In addition, small styrofoam particles are mixed into the control samples in all batches to simulate microvoids in damaged concrete. The exciting frequency ranges from a low frequency at 50 kHz to a demium frequency at 300 to 400 kHz to demonstrate the frequency effect upon the ultrasonic NDE of concrete for each batch. The grain size also affects the concrete microstructure and influences the propagation and attenuation of ultrasonic waves through undamaged and damaged concrete specimens.
Elastodynamic Response of a Chain of Particles
Authors: Kinra Vikram K. , Henderson Benjamin K. , Maslov Konstantin
Published: December 2021

The reflection of an axially incident plane longitudinal wave from a linear chain of identical spherical inclusions embedded in a viscoelastic matrix is measured. The reflection spectrum is characterized by a sequence of resonances corresponding to the Floquet condition, where an integral number of half-wavelengths in the matrix spans the interparticle distance.
The Dynamic Electromechanical Behaviour of Advanced Composites Incorporating Piezoelectric Fibres
Authors: Wang X. D.
Published: December 2021

This paper provides a comprehensive treatment of the electromechanical behaviour of fibre reinforced piezoelectric composites under steady-state dynamic loading. The composites are modelled as two-dimensional media with interacting piezoelectric inhomogeneities. The original problem is decomposed into single inhomogeneity subproblems, which are solved by using Fourier expansions. The solutions of these subproblems are then summed up in a consistent manner to provide a system of linear algebraic equations, from which the dynamic electromechanical field in the composites can be determined. Numerical examples are provided to show the effect of the interaction between piezoelectric fibres, the material mismatch and the loading frequency upon the dynamic local stress field and electrical response of the composites.
Equivalent Composite Laminated Beams With Various Elastic Constitutive Models
Authors: Sheinman Izhak , Frostig Yeoshua
Published: December 2021

Equivalent one-dimensional constitutive models of composite laminated beams with shear deformation are derived from the classical laminate two-dimensional using first-order shear deformable theory. The present cylindrical bending constitutive models can be used — with much greater accuracy than their well known plane-strain and plane-stress counterparts — as upper and lower bounds, to one of which the behavior tends depending on the width-to-length ratio; this aspect was investigated and results are presented.
Reliability Analysis of Flip Chip on Board Assemblies Using No-Flow Underfill Materials
Authors: Thorpe Ryan , Baldwin Daniel F.
Published: December 2021

As a concept to achieve high throughput low cost flip chip on board (FCOB) assembly, a process development activity and reliability assessment is underway, implementing next generation flip chip processing based on large area underfill printing/dispensing, integrated chip placement and underfill flow, and simultaneous solder interconnect reflow and underfill cure. Reported in this work is the assembly of a series of test vehicles to evaluate the reliability of no-flow underfill materials. The reliability performance of four underfill materials is evaluated using six test vehicles. Accelerated reliability tests performed on the test vehicles included liquid/liquid and air/air thermal cycling, autoclave, and J-STD-020 Level 3 preconditioning. No-flow underfill materials tested in this work have demonstrated the ability to survive in excess of 1000 cycles of liquid/liquid thermal shock, survive more than 100 hours of autoclave, and pass J-STD-020 Level 3 preconditioning.
A Performance & Manufacturability Evaluation of Bump Chip Carrier Packages
Authors: Mercado Lei L. , Sarihan Vijay , Fiorenzo Russell
Published: December 2021

Bump Chip Carrier® (BCC) is an attractive solution to the demand of high packaging density of low I/O-count packages. It offers low cost, high performance, and much smaller package size than Quad Flat Packages (QFP). Electrically, BCC offers significant performance advantage as a function of frequency. It also has customizable configurations. In this paper, an extensive finite element thermomechanical analysis has been conducted to evaluate the reliability of BCC packages during thermal cycling. The effect of a variety of parameters on package reliability was evaluated, including board thickness, package size mold material, solder paste thickness, and terminal height. The solder reliability of corner leads vs. inner leads, as well as square leads vs. rectangular leads was also investigated. Then some manufacturing issues were studied. During manufacturing, molded panels for BCC packages are undergoing significant warpage. Two types of mold designs were compared through 3D finite element analysis. A variety of mold compound materials were evaluated. The most effective way to reduce warpage was suggested.
Artwork Scaling Factor for Inner Layers in Multi-Layer Board Manufacture
Authors: Christofferson Owen , Sahay Chittaranjan
Published: December 2021

Demands for high-density multi-layer printed circuits continue to push the limits of common materials and process capabilities. Materials and processes that can improve current manufacturing tolerances will improve yields on current designs as well as free up printed circuit board real estate for increased circuit densities. Achieving these improvements requires an understanding of all the variables that contribute to inner layer feature-to-drilled hole registration and how tolerances stack up to an overall capability. These variables include both material types and process parameters. This paper discusses the variables that affect overall registration capabilities, presents a technique for predicting artwork scaling factors.
Performance of Thermal Enhancements in Chip on Flex
Authors: Miller Gary , Sahay Chittaranjan
Published: December 2021

The paper describes the development of encapsulated multiple chip on flex (COF) as Industry Common Building Blocks (CBB) as an economic alternative to high cost Application Specific Integrated Circuits (ASIC). Lockheed Martin/ General Electric developed the high density interconnect (HDI) structure used in these modules. The successful implementation of such CBB has been demonstrated in a F414 FADEC (Full Authority Digital Engine Control). The paper describes the construction of these COF CBB modules and their thermal performance with several thermal enhancement techniques.
A Mixture of Elastic Materials With Internal Constraints
Authors: Klisch Stephen M.
Published: December 2021

A treatment of internally constrained mixtures of elastic materials at a common temperature is developed. Internal constraints involving the deformation gradient tensors and the common mixture temperature are represented by a constraint manifold, and an internally constrained mixture of elastic materials is associated with each unique equivalence class of unconstrained mixtures. Several examples are discussed.
Stability of Elastic Half-Spaces by an Energy Method
Authors: Chen Yi-chao , Wheeler Lewis T.
Published: December 2021

An energy stability criterion is used to study the stability of deformations of a compressible elastic half-space. A minimization problem is formulated in an unbounded domain, and the first and second variation conditions are derived for this problem. Algebraic stability conditions are derived for general compressible isotropic materials, as well as for neo-Hookean class of Hadamard materials.