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The purpose of this paper is to present a semi-analytical solution to one-dimensional (1D) consolidation induced by a constant inner point sink in viscoelastic saturated soils.

Based on the Kelvin–Voigt constitutive law and 1D consolidation equation of saturated soils subject to an inner sink, the analytical solutions of the effective stress, the pore pressure and the surface settlement in Laplace domain were derived by using Laplace transform. Then, the semi-analytical solutions of the pore pressure and the surface settlement in physical domain were obtained by implementing Laplace numerical inversion via Crump method.

As for the case of linear elasticity, it is shown that the simplified form of the presented solution in this study is the same as the available analytical solution in the literature. This to some degree depicts that the proposed solution in this paper is reliable. Finally, parameter studies were conducted to investigate the effects of the relevant parameters on the consolidation settlement of saturated soils. The presented solution and method are of great benefit to provide deep insights into the 1D consolidation behavior of viscoelastic saturated soils.

The presented solution and method are of great benefit to provide deep insights into the 1D consolidation behavior of viscoelastic saturated soils. Consolidation behavior of viscoelastic saturated soils could be reasonably predicted by using the proposed solution with considering variations of both flux and depth because of inner point sink.

The purpose of the study is to optimise the cross-sectional shape of passively cooled horizontally mounted pin-fin heat sink for higher cooling performance and lower material usage.

Multi-objective shape optimisation technique is used to design the heat sink fins. Non-dominated sorting genetic algorithm (NSGA-II) is combined with a geometric module to develop the shape optimiser. High-fidelity computational fluid dynamics (CFD) is used to evaluate the design objectives. Separate optimisations are carried out to design the shape of bottom row fins and middle row fins of a pin-fin heat sink. Finally, a computational validation was conducted by generating a three-dimensional pin-fin heat sink using optimised fin cross sections and comparing its performance against the circular pin-fin heat sink with the same inter-fin spacing value.

Heat sink with optimised fin cross sections has 1.6% higher cooling effectiveness than circular pin-fin heat sink of same material volume, and has 10.3% higher cooling effectiveness than the pin-fin heat sink of same characteristics fin dimension. The special geometric features of optimised fins that resulted in superior performance are highlighted. Further, Pareto-optimal fronts for this multi-objective optimisation problem are obtained for different fin design scenarios.

For the first time, passively cooled heat sink’s cross-sectional shapes are optimised for different spatial arrangements, using NSGA-II-based shape optimiser, which makes use of CFD solver to evaluate the design objectives. The optimised, high-performance shapes will find direct application to cool power electronic equipment.

The purpose of this paper is to present two efficient immersed boundary methods (IBM) for simulation of thermal flow problems. One method is for given temperature condition (Dirichlet type), while the other is for given heat flux condition (Neumann type). The methods are applied to simulate natural and mixed convection problems to check their performance. The comparison of present results with available data in the literature shows that the present methods can obtain accurate numerical results efficiently.

The paper presents two efficient IBM solvers, in which the effect of thermal boundary to its surrounding fluid is considered through the introduction of a heat source/sink term into the energy equation. One is the temperature correction‐based IBM developed for problems with given temperature on the wall. The other is heat flux correction‐based IBM for problems with given heat flux on the wall. Note that in this solver, the offset of derivative condition is directly used to correct the temperature field.

As compared with existing solvers, the temperature correction‐based IBM determines the heat source/sink implicitly instead of pre‐calculated explicitly, so that the boundary condition for temperature is accurately satisfied. To the best of the authors' knowledge, the work of heat flux correction‐based IBM is the first endeavour for application of IBM to solve thermal flow problems with Neumann (heat flux) boundary condition. It was found that both methods presented in this work can efficiently obtain accurate numerical results for thermal flow problems.

The two methods presented in this paper are novel. They can effectively solve thermal flow problems with Dirichlet and Neumann boundary conditions.

With the increasing demand for lightweight parts, the quality of the inner structure gained growing attention from different kinds of fields. As the quality of the overhanging surface was one of the most important factors affecting inner structure formation, its quality still needs to improve. This paper aims to clarify the change of the overhanging surface quality caused by different bending angles.

The structure of the inner hole was redesigned according to the different performances of the overhanging and side inner surface. The experimental results revealed why different surface qualities can be seen under different bending angles. According to the experimental data, the inner structure was redesigned to increase its overall performance.

The results revealed that when the bending angle was small, the slope of the overhanging surface increased which lead to the decreasing length of the powder-supported layer. However, less space on bending angle resulted in the accumulation of unmelted powder which leads to the increasing of sinking distance. When the bending angle was too large, the slope of the overhanging surface decreased and the length of the molten pool which was supported by powder increased. It resulted in the sinking of the molten pool caused by the gravity of powder and its attachment.

This paper is the first work to study the relationship between bending angle and overhanging surface quality as far as the authors know. The different performances of left and right overhanging surfaces also have not been revealed in other research studies to the best of the knowledge.

The purpose of this paper is to explore the reasons why customers often cannot or do not exit a negative service encounter (lock-in) and to discuss how this affects their well-being and coping responses. This contributes to the research on how negative service encounters emerge and evolve and how such encounters impact customer well-being and subsequent responses.

An inductive, exploratory approach was used. Interviews with 20 service customers yielded over 90 detailed lock-in experiences across 25 different services. A multi-step, iterative coding process was used with a mixture of coding techniques that stem from a grounded theory approach.

Four categories of factors that caused customers to endure a negative event were identified (physical lock-in, dependency on the service, social lock-in and psychological lock-in). Customers either experienced inner turmoil (if they perceived having the option to stay or leave) or felt captive; both impacted their well-being and coping strategies in different ways. Three characteristics of negative events that caused lock-in to persist over time were identified.

This is a qualitative study that aims to identify factors behind customer lock-in, reduced well-being and coping strategies across different types of service encounters. Future research may build on these themes to investigate lock-in during specific service encounters in greater depth.

This research provides insights regarding how service providers can anticipate lock-in situations. In addition, the findings point to several ways in which frontline employees can assist customers with the coping process, during lock-in.

Customer lock-in during a service encounter is a common, yet unexplored phenomenon. This research contributes to a better understanding of why customers endure negative events and how such perceptions are reflected in their experiences and behaviors.

The analysis of fluid flow and thermal transport performance inside the cavity has found numerous applications in various engineering fields, such as nuclear reactors and solar collectors. Nowadays, researchers are concentrating on improving heat transfer by using ternary nanofluids. With this motivation, the present study analyzes the natural convective flow and heat transfer efficiency of ternary nanofluids in different types of porous square cavities.

The cavity inclination angle is fixed ω = 0 in case (I) and ω=π4 in case (II). The traditional fluid is water, and Fe3O4+MWCNT+Cu/H2O is treated as a working fluid. Ternary nanofluid's thermophysical properties are considered, according to the Tiwari–Das model. The marker-and-cell numerical scheme is adopted to solve the transformed dimensionless mathematical model with associated initial–boundary conditions.

The average heat transfer rate is computed for four combinations of ternary nanofluids: Fe3O4(25%)+MWCNT(25%)+Cu(50%),Fe3O4(50%)+MWCNT(25%)+Cu(25%),Fe3O4(33.3%)+MWCNT(33.3%)+Cu(33.3%) and Fe3O4(25%)+MWCNT(50%)+Cu(25%) under the influence of various physical factors such as volume fraction of nanoparticles, inclined magnetic field, cavity inclination angle, porous medium, internal heat generation/absorption and thermal radiation. The transport phenomena within the square cavity are graphically displayed via streamlines, isotherms, local and average Nusselt number profiles with adequate physical interpretations.

The purpose of this study is to determine whether the ternary nanofluids may be used to achieve the high thermal transmission in nuclear power systems, generators and electronic device applications.

The current analysis is useful to improve the thermal features of nuclear reactors, solar collectors, energy storage and hybrid fuel cells.

To the best of the authors’ knowledge, no research has been carried out related to the magneto-hydrodynamic natural convective Fe3O4+MWCNT+Cu/H2O ternary nanofluid flow and heat transmission filled in porous square cavities with an inclined cavity angle. The computational outcomes revealed that the average heat transfer depends not only on the nanoparticle’s volume concentration but also on the existence of heat source and sink.

This paper sets out to optimize the shape and size of microchannels cooling heat sink, which has been widely used to cool electronic chip for its high heat transfer coefficient and compact structure.

Sequential Quadratic Programming (SQP) method is used to optimize the cross‐section sizes of microchannels. Finite volume method is used to numerically simulate the cooling performance of optimal microchannel cooling heat sink.

The optimized cross‐section shape of microchannel is rectangular, and the width and depth of microchannel is 50 and 1,000 μm, respectively, the number of microchannels is 60, and the corresponding least thermal resistance is 0.115996°C/W. The results show that the heat transfer performance of microchannel cooling heat sink is affected intensively by its cross‐section shape and dimension. The convection heat resistance R_conv between inner surface in microchannels and working fluid has more influence in the total heat resistance. The heat flux of chip is 278 W/cm² and, through the optimization microchannel cooling heat sink, the highest temperature in the chip can be kept below 42°C, which is about half of that without optimizing heat sink and can ensure the stability and reliability of chip.

The convection heat transfer coefficient is calculated approximatively here for convenience, and that may induce some errors.

The optimized microchannels cooling heat sink may satisfy the request for removal of high heat flux in new‐generation chips.

A review of state‐of‐the‐art technology pertinent to tape automated bonding (for fine pitch, high I/O, high performance, high yield, high volume and high reliability) is presented. Emphasis is placed on a new understanding of the key elements (for example, tapes, bumps, inner lead bonding, testing and burn‐in on tape‐with‐chip, encapsulation, outer lead bonding, thermal management, reliability and rework) of this rapidly moving technology.

The purpose of this paper was to show physical limitation of embedding standard packaging components into printed circuit board (PCB) which is more reasonable technology for small series productions which is popular in industrial products. Embedding electronic components inside a PCB FR-4 substrate leads to significant size reduction and better heat management. Embedded chip technology is already known in many consumer electronics applications, but it is focused on high volumes and required to order components ready to be embedded.

Highly integrated DC/DC converter with standard-package electronic parts (passive and active) was embedded inside a PCB structure. The design and the manufacturing process was based on standard PCB FR-4 technology. Sandwich solution was used to integrate all layers together; one of the main investigations was to focus on how to fill space around components to keep internal stresses on very low level.

There were few considerations during choosing the right concept. The first, which occurred during the first producing round, was the distance between thick copper and inner layer. The second one was the way how to fill space between mounted components on inner layer and isolation laminate. A few trials took place and it is decided that it is impossible to fill this space with resin from prepregs; therefore, a casting compound was used.

Design and manufacturing process which brings 37 per cent of size reduction of complete DC/DC voltage converter PCB with 28.5 W output power comparing to a reference design with standard surface mounted devices (SMD) and copper layout implementation has been achieved during research project.