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Article
Publication date: 21 September 2015

Hailing Hou, Shihong Yue, Xiaoguang Huang and Huaxiang Wang

This paper aims to discuss flow pattern transition (FPT) as an important factor in multiple-phase flow measurements. Several methods have been proposed to control FPT, but…

Abstract

Purpose

This paper aims to discuss flow pattern transition (FPT) as an important factor in multiple-phase flow measurements. Several methods have been proposed to control FPT, but those methods fail to address the many issues in complex flow conditions that can affect flow patterns.

Design/methodology/approach

In this paper, a non-intrusive sensor instrumentation is applied to extract measurable data under different flow conditions. Using these data, a simple theoretical–mathematical method along with an orthogonal design is applied to FPT optimization. Orthogonal experiments are designed and carried out according to theoretical guidelines. Three selected process parameters – phase fraction, gas pressure in the initial independent process and liquid speed – are optimized for FPT results to produce a minimum FPT time.

Findings

The following results are obtained: the phase fraction in the initial independent process can lead to significant reductions in FPT time, gas pressure plays an important role and liquid speed has no apparent effect on FPT results. Under optimized conditions, FPT time can be shortened to 0.3-0.6 times by controlling the above three parameters compared with normal conditions.

Originality/value

The proposed method is simple, rapid and efficient for evaluating an FPT process and lays the foundation for further FPT applications.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

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Book part
Publication date: 15 January 2010

Michiel C.J. Bliemer and John M. Rose

Stated choice experiments can be used to estimate the parameters in discrete choice models by showing hypothetical choice situations to respondents. These attribute levels…

Abstract

Stated choice experiments can be used to estimate the parameters in discrete choice models by showing hypothetical choice situations to respondents. These attribute levels in each choice situation are determined by an underlying experimental design. Often, an orthogonal design is used, although recent studies have shown that better experimental designs exist, such as efficient designs. These designs provide more reliable parameter estimates. However, they require prior information about the parameter values, which is often not readily available. Serial efficient designs are proposed in this paper in which the design is updated during the survey. In contrast to adaptive conjoint, serial conjoint only changes the design across respondents, not within-respondent thereby avoiding endogeneity bias as much as possible. After each respondent, new parameters are estimated and used as priors for generating a new efficient design. Results using the multinomial logit model show that using such a serial design, using zero initial prior values, provides the same reliability of the parameter estimates as the best efficient design (based on the true parameters). Any possible bias can be avoided by using an orthogonal design for the first few respondents. Serial designs do not suffer from misspecification of the priors as they are continuously updated. The disadvantage is the extra implementation cost of an automated parameter estimation and design generation procedure in the survey. Also, the respondents have to be surveyed in mostly serial fashion instead of all parallel.

Details

Choice Modelling: The State-of-the-art and the State-of-practice
Type: Book
ISBN: 978-1-84950-773-8

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Article
Publication date: 27 November 2018

Cunfu Yan, Shujuan Li, Leipeng Yang and Longfei He

The purpose of this paper is to investigate the effects of parameters on the liquid phase migration (LPM) during the freeze-form extrusion fabrication (FEF) process.

Abstract

Purpose

The purpose of this paper is to investigate the effects of parameters on the liquid phase migration (LPM) during the freeze-form extrusion fabrication (FEF) process.

Design/methodology/approach

To carry out this study, three factors were systematically investigated using orthogonal design of experiments. These three parameters are the extrusion velocity, the extrusion interval time and the extrusion head length. An orthogonal array with nine test units was selected for the experiments. Range analysis and analysis of variance were used to analyze the data obtained by the orthogonal experiments to identify the order of significant factors on LPM.

Findings

It was found that the LPM decreased with the increase of extrusion velocity and increased with the lengthening of extrusion interval time and the length of the extrusion nozzle. The order of significant factors for the LPM were found to be extrusion velocity > extrusion nozzle length > extrusion interval time.

Practical implications

Using an orthogonal design of experiments and a statistical analysis method, the liquid content of extrudate can be predicted and appropriate process parameter values can be selected. This leads to the minimization of LPM during the FEF process. Also, this analysis method could be used to study the LPM in other paste extrusion processes.

Originality/value

This paper suggests that the factors have significant impact on LPM during FEF process. The following analysis in this paper is useful for FEF users when prediction of LPM is needed. This methodology could be easily applied to different materials and initial conditions for optimization of other FEF-type processes. The research can also help to get better understanding of LPM during the FEF process.

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Article
Publication date: 6 February 2017

Qiang Fang, Weidong Chen, Anan Zhao, Changxi Deng and Shaohua Fei

In aircraft wing–fuselage assembly, the distributed multi-point support layout of positioners causes fuselage to deform under gravity load, leading to assembly difficulty…

Abstract

Purpose

In aircraft wing–fuselage assembly, the distributed multi-point support layout of positioners causes fuselage to deform under gravity load, leading to assembly difficulty and assembly stress. This paper aims to propose a hybrid force position control method to balance aerodynamic shape accuracy and deformation of assembly area, thereby correcting assembly deformation and reducing assembly stress.

Design/methodology/approach

Force and position control axes of positioners are selected based on screw theory and ellipsoid method. The position-control axes follow the posture trajectory to align the fuselage posture. To exert force on the fuselage and correct the deformations, the force-control axes follow the contact force derived by using orthogonal experiments and partial least squares regression (PLSR). Finite element simulation and one-dimension deformation correction experiment are conducted to verify the validity of this method.

Findings

Simulation results indicate that hybrid force position control method can correct assembly deformation and improve the wing–fuselage assembly quality significantly. Experiment on specimen verifies the effect of this method indirectly.

Originality/value

The proposed method gives a solution to solve the deformation problem during aircraft wing-fuselage assembly, thereby reducing assembly stress and improving assembly quality.

Details

Assembly Automation, vol. 37 no. 1
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 14 September 2015

Lin Ba, Zhenpeng He, Lingyan Guo, Young Chiang, Guichang Zhang and Xing Lu

The purpose of this paper is to improve the environment and save energy, friction reduction, lower oil consumption and emissions demand that are the chief objectives of…

Abstract

Purpose

The purpose of this paper is to improve the environment and save energy, friction reduction, lower oil consumption and emissions demand that are the chief objectives of the automotive industry. The piston system is the largest frictional loss source, which accounts for about 40 per cent of the total frictional loss in engine. In this paper, the reciprocating tribometer, which is updated, was used to evaluate the friction and wear performances.

Design/methodology/approach

An alternate method is introduced to investigate the effect of reciprocating speed, normal load, oil pump speed and ring sample and oil temperature on friction coefficient with the ring/liner of a typical inline diesel engine. The orthogonal experiment is designed to identify the factors that dominate wear behavior. To understand the correlations between friction coefficients and wear well, different friction coefficient results were compared and explained by oil film build-up and asperity contact theory, such as the friction coefficient over a long period and averaged the friction coefficient over one revolution.

Findings

The friction coefficient changes little but fluctuates with a small amplitude in the stable stage. The sudden change of frequency, load and stroke will lead to the oil film rupture. The identification for the factors that dominates the wear loss is ranged as F (ring sample) > , E (oil sample) > , B (stroke) > , D (temperature) > , A (load) > , G (liner) > and C (frequency).

Originality/value

This paper develops and verifies a methodology capable of mimicking the real engine behavior at boundary and mixed lubrication regimes which can minimize frictional losses, wear, reduce much work for the experiment and reduce the cost. The originality of the work is well qualified, as very few papers on a similar analysis have been published, such as: The friction coefficient values fluctuating in the whole stage may be caused by the vibration of the system; suddenly, boundary alternation may help the oil film to form the lubrication; and weight loss mainly comes from the contribution of the friction coefficient value fluctuation. The paper also found that the statistics can gain more information from less experiment time based on a design of experiment.

Details

Industrial Lubrication and Tribology, vol. 67 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 29 June 2020

Dong Liu, Minghao Wang, Naiyu Fang, Ming Cong and Yu Du

Varied shapes and sizes of different products with irregular rough surface and fragile properties give a challenge to traditional contact gripping. Single Bernoulli…

Abstract

Purpose

Varied shapes and sizes of different products with irregular rough surface and fragile properties give a challenge to traditional contact gripping. Single Bernoulli grippers are not suited to handle fragile objects as the impact of center negative pressure force could result in large deformation and stress which damage the materials, and they are also have some limitations for gripping objects with different large and small shapes. Thus, this paper aims to design a non-contact gripper for soft, rough-surfaced and fragile objects gripping with multi Bernoulli heads, which have optimal structures and parameters.

Design/methodology/approach

The compressed air is ejected into four Bernoulli heads through radial and long flow channels, then passes through four strip-shaped narrow gaps after fully developing in the annular cavity to provide negative pressure. Based on the mathematic model and the computational model, the key structural parameters affecting the gripping performance are selected, and parameters optimization of the gripper is performed by computational fluid dynamics simulation analysis and performance evaluation. The orthogonal method is used and L16 orthogonal array is selected for experimental design and optimization. The characteristics of the designed gripper are tested from the aspects of pressure distribution and lifting force.

Findings

From the applications in gripping different objects, the designed non-contact gripper can grip varied shapes and sizes of soft, rough-surfaced, fragile and sliced objects with little effect of torque.

Originality/value

In this paper, a non-contact gripper is designed for handling soft, rough-surfaced and fragile objects based on the Bernoulli principle. A systematic approach, which consists of modeling, simulation, optimization and measurement is provided for the non-contact gripper design and tests.

Details

Assembly Automation, vol. 40 no. 5
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 8 April 2021

Yaolin Lin and Wei Yang

The purpose of this paper is to present a tri-optimization approach to optimize design solutions regarding the building shape and envelope properties considering their…

Abstract

Purpose

The purpose of this paper is to present a tri-optimization approach to optimize design solutions regarding the building shape and envelope properties considering their implications on thermal comfort, visual comfort and building energy consumption (EN). The optimization approach has been applied to obtain the optimal design solutions in five typical cities across all climatic regions of China.

Design/methodology/approach

The method comprises a tri-optimization process with nine main steps to optimize the three objectives (thermal comfort, visual comfort and building EN). The design variables considered are four types of building shape (pyramid, rectangular, cylindrical and dome shape) and different envelope properties (insulation thickness [INS] of external walls/roof, window type [WT] and window-to-envelop surface area ratio [WESR]). The optimization is performed by using the Taguchi and constraint limit method.

Findings

The results show that the optimal design solutions for all climatic regions favor cylindrical shape and triple-layer low-E glazing window. The highest insulation level of 150 mm is preferred in three climatic regions, and the INS of 90 mm is preferred in the other two climate regions. In total, 10% WESR is preferred in all climatic regions, except the mild region. When the constraint limit of lighting intensity requirement by Leadership in Energy and Environmental Design (LEED) is applied, the rectangular shape building is the optimal solution for those with 10% WESR.

Research limitations/implications

The method proposed in the paper is innovative in that it optimizes three different objectives simultaneously in building design with better accuracy and calculation speed.

Practical implications

Building designers can easily follow the proposed design guide in their practice which effectively bridges the gap between theory and practice. The optimal design solutions can provide a more comfortable living environment and yet less EN, which can help achieve the sustainability requirement of green buildings.

Social implications

The solutions presented in the paper can serve as a useful guide for practical building designers which creates economic and commercial impact. In addition, the theory and practical examples of the study can be used by building regulators to improve the energy-efficient building design standard in China.

Originality/value

The research is the first attempt that adopts tri-optimization approach to generate the optimal solutions for building shape and envelope design. The tri-optimization approach can be used by building designers to generate satisfactory design solutions from the architectural viewpoint and meanwhile to find combinations of the building shape and envelope properties that lead to design solutions with optimal building performance.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

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Article
Publication date: 1 April 2002

C.Y. Huang

The underfilling of flip chip components with the encapsulant is based on the principles of capillary flow. A reasonable understanding of capillary flow and an effective…

Abstract

The underfilling of flip chip components with the encapsulant is based on the principles of capillary flow. A reasonable understanding of capillary flow and an effective estimate of the encapsulant's flow time will help develop a robust process. Factors which may influence the encapsulant's flow rate and its variation include the material type (viscosity, wetting characteristics, silicon particle size, etc.), the aging of the material, the substrate preheat temperature, the chemical composition and texture of the flow surface, standoff height, and the presence of obstructions (solder bumps).A screening experiment through the use of orthogonal array was conducted to determine the factors which would have a significant effect on the encapsulant's flow rate. The screening experiments served as a precursor to subsequent process modeling and the identification of a robust process design. Comprehensive experiments were then performed to further investigate the flow behavior of the underfill materials with realistic properties.

Details

Microelectronics International, vol. 19 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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Article
Publication date: 13 August 2019

Ming-Yue Xiong, Liang Zhang, Peng He and Wei-Min Long

The transistor circuit based on Moore's Law is approaching the performance limit. The three-dimensional integrated circuit (3-D IC) is an important way to implement More…

Abstract

Purpose

The transistor circuit based on Moore's Law is approaching the performance limit. The three-dimensional integrated circuit (3-D IC) is an important way to implement More than Moore. The main problems in the development of 3-D IC are Joule heating and stress. The stresses and strains generated in 3-D ICs will affect the performance of electronic products, leading to various reliability issues. The intermetallic compound (IMC) joint materials and structures are the main factors affecting 3-D IC stress. The purpose of this paper is to optimize the design of the 3-D IC.

Design/methodology/approach

To optimize the design of 3-D IC, the numerical model of 3-D IC was established. The Taguchi experiment was designed to simulate the influence of IMC joint material, solder joint array and package size on 3-D IC stress.

Findings

The simulation results show that the solder joint array and IMC joint materials have great influence on the equivalent stress. Compared with the original design, the von Mises stress of the optimal design was reduced by 69.96 per cent, the signal-to-noise ratio (S/N) was increased by 10.46 dB and the fatigue life of the Sn-3.9Ag-0.6Cu solder joint was increased from 415 to 533 cycles, indicating that the reliability of the 3-D IC has been significantly improved.

Originality/value

It is necessary to study the material properties of the bonded structure since 3-D IC is a new packaging structure. Currently, there is no relevant research on the optimization design of solder joint array in 3-D IC. Therefore, the IMC joint material, the solder joint array, the chip thickness and the substrate thickness are selected as the control factors to analyze the influence of various factors on the 3-D IC stress and design. The orthogonal experiment is used to optimize the structure of the 3-D IC.

Details

Soldering & Surface Mount Technology, vol. 32 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 2 October 2007

John Kechagias

To investigate laminated object manufacturing (LOM) process quality, using a design of experiments approach.

Abstract

Purpose

To investigate laminated object manufacturing (LOM) process quality, using a design of experiments approach.

Design/methodology/approach

The quality characteristics measured were in‐plane dimensional accuracy, actual layer thickness (ALT), and mean time per layer. The process parameters tested were nominal layer thickness (LT), heater temperature (HT), platform retract (PR), heater speed (HS), laser speed (LS), feeder speed (FS) and platform speed (PS). A typical test part has been used, and matrix experiments were carried out based on Taguchi design. Optimal process parameter values were identified and finally, additive and regression models were applied to the experimental results and tested using evaluation experiments.

Findings

The statistical analysis of the experimental results shows that error in X direction was higher than error in Y direction. Dimensional accuracy in X direction depends mainly on the HS (89 percent) and HT (5 percent), and in Y direction on HS (50 percent), LT (31 percent), LS (9 percent), PS (6 percent), and HT (3 percent). On the other hand, ALT depends mainly on the nominal ALT (96 percent), HS (2 percent), HT (1 percent), and PR (1 percent). Finally, mean time per layer depends mainly on HS (59 percent), LS (17 percent), FS (17 percent), and PS (4 percent).

Research limitations/implications

Future work should involve extensive matrix experiments using parameters such as dimensions of test part (Xmax, Ymax, Zmax), hatch spacing in X and Y directions, and delay time between sequential layers.

Practical implications

Using the extracted models, the quality of LOM parts can be predicted and appropriate process parameter values selected. This means minimization of post processing time, easier disengagement between supporting frame and part, easier decubing, process optimization, less finishing and satisfactory final LOM parts or tools. Also, ALT prediction and mean time per layer analysis could be used to improve LOM build time predictions.

Originality/value

The above analysis is useful for LOM users when predictions of part quality, paper consumption, and build time are needed. This methodology could be easily applied to different materials and initial conditions for optimisation of other LOM‐type processes.

Details

Rapid Prototyping Journal, vol. 13 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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