Effect of the multi-sized nanoparticle distribution on the thermal conductivity of nanofluids

Recent studies of nanofluids have shown that the nanoparticles when mixed in fluid medium such as water and ethylene glycol enhance the thermal conductivity of the colloids when compared to the fluid medium. However, numerous experimental studies conducted on the effective thermal conductivity of nanofluids, while using initial particle distribution consisting of range of diameters, have reported their results at volume-weighted average diameters. Here, we use computer simulations to investigate the effect of initial particle distribution or the effect of polydispersivity on the effective thermal conductivity of nanofluids. The study reveals that the simulations performed with multi-sized nanoparticles predict the effective thermal conductivity values of nanofluids closer to the experimental values than the corresponding volume weighted average diameters. Inhomogeneous coagulations in the multi-sized nanofluids were found to be a major factor for the deviation of effective thermal conductivity of the nanofluids in single- and multi-sized nanofluids. Our results suggest that initial distribution of particles has a significant role in predicting the effective thermal conductivity of nanofluids.     

Experimental study of thermal conductivity and phase change performance of nanofluids PCMs

A new sort of nanofluids phase change materials (PCMs) is developed by suspending small amount of TiO₂ nanoparticles in saturated BaCl₂ aqueous solution. The resulting nanofluids PCMs possess remarkably high thermal conductivities compared to the base material. Cool storage/supply experiments conducted in a small apparatus have shown the excellent phase change performance of the nanofluids PCMs. The cool storage/supply rate and the cool storage/supply capacity all increase greatly those that of BaCl₂ aqueous solution without added nanoparticles. The higher thermal performances of nanofluids PCMs indicate that they have a potential for substituting conventional PCMs in cool storage applications.     

Preparation, characterization, viscosity and thermal conductivity of CaCO_3 aqueous nanofluids

CaCO3 aqueous nanofluids were prepared by dispensing aqueous CaCO3 paste into distilled water under ultrasonic vibration. The actual microstructures of the CaCO3 nanofluids with different particle volume fractions were characterized by freeze etching replication transmission electron microscopy (FERTEM). Thermal conductivity and rheological behavior of the nanofluids were measured by standard analyzers. The results show that CaCO3 paste as raw material for nanofluids is advantageous to reducing aggregation ...     

Preview-based techniques for vehicle suspension control: a state-of-the-art review

Automotive suspension systems are key to ride comfort and handling performance enhancement. In the last decades semi-active and active suspension configurations have been the focus of intensive automotive engineering research, and have been implemented by the industry. The recent advances in road profile measurement and estimation systems make road-preview-based suspension control a viable solution for production vehicles. Despite the availability of a significant body of papers on the topic, the literature lacks a comprehensive and up-to-date survey on the variety of proposed techniques for suspension control with road preview, and the comparison of their effectiveness. To cover the gap, this literature review deals with the research conducted over the past decades on the topic of semi-active and active suspension controllers with road preview. The main formulations are reported for each control category, and the respective features are critically analysed, together with the most relevant performance indicators. The paper also discusses the effect of the road preview time on the resulting system performance, and identifies control development trends.     

Developing serious games for cultural heritage: a state-of-the-art review

Although the widespread use of gaming for leisure purposes has been well documented, the use of games to support cultural heritage purposes, such as historical teaching and learning, or for enhancing museum visits, has been less well considered. The state-of-the-art in serious game technology is identical to that of the state-of-the-art in entertainment games technology. As a result, the field of serious heritage games concerns itself with recent advances in computer games, real-time computer graphics, virtual and augmented reality and artificial intelligence. On the other hand, the main strengths of serious gaming applications may be generalised as being in the areas of communication, visual expression of information, collaboration mechanisms, interactivity and entertainment. In this report, we will focus on the state-of-the-art with respect to the theories, methods and technologies used in serious heritage games. We provide an overview of existing literature of relevance to the domain, discuss the strengths and weaknesses of the described methods and point out unsolved problems and challenges. In addition, several case studies illustrating the application of methods and technologies used in cultural heritage are presented.     

Product family design and platform-based product development: a state-of-the-art review

Product family design and platform-based product development has received much attention over the last decade. This paper provides a comprehensive review of the state-of-the-art research in this field. A decision framework is introduced to reveal a holistic view of product family design and platform-based product development, encompassing both front-end and back-end issues. The review is organized according to various topics in relation to product families, including fundamental issues and definitions, product portfolio and product family positioning, platform-based product family design, manufacturing and production, as well as supply chain management. Major challenges and future research directions are also discussed.     

Utilization of secret sharing technology for secure communication: a state-of-the-art review

Multimedia Tools and Applications - Cryptography is the process by which a readable message is converted into cipher-text unintelligible to an eavesdropper. With the advent of the internet,...     

Feature selection in multimedia: The state-of-the-art review

Multimedia data mining, particularly feature selection (FS), has been successfully applied in recent classification and recognition works. However, only a few studies in the contemporary literature have reviewed FS (e.g., analyses of data pre-processing prior to classification and clustering). This study aimed to fill this research gap by presenting an extensive survey on the current development of FS in multimedia. A total of 70 related papers published from 2001 to 2017 were collected from multiple databases. Breakdowns and analyses were performed on data types, methods, search strategies, performance measures, and challenges. The development trend of FS presages the increased prominence of heuristic search strategies and hybrid FS in the latest multimedia data mining.     

Multisensor data fusion: A review of the state-of-the-art

There has been an ever-increasing interest in multi-disciplinary research on multisensor data fusion technology, driven by its versatility and diverse areas of application. Therefore, there seems to be a real need for an analytical review of recent developments in the data fusion domain. This paper proposes a comprehensive review of the data fusion state of the art, exploring its conceptualizations, benefits, and challenging aspects, as well as existing methodologies. In addition, several future directions of research in the data fusion community are highlighted and described.     

Integration of job shop control systems: A state-of-the-art review

This paper reviews important theoretical and practical developments in job shop control. The distinguishing feature of this paper is the identification and summary of important concepts and procedures useful for incorporation into computerized job shop control systems. The first section briefly examines the job shop control problem, and presents a broad outline of commonly used subproblems and methods. A review of the past work done in the areas of scheduling and sequencing, workload balancing, work flow structure analysis, and job shop capability evaluation is then presented. The final section lists important concepts and procedures for developing computer integrated job shop control systems.     

Managing obesity through mobile phone applications: a state-of-the-art review from a user-centred design perspective

Evidence has shown that the trend of increasing obesity rates has continued in the last decade. Mobile phone applications, benefiting from their ubiquity, have been increasingly used to address this issue. In order to increase the applications’ acceptance and success, a design and development process that focuses on users, such as user-centred design, is necessary. This paper reviews reported studies that concern the design and development of mobile phone applications to prevent obesity, and analyses them from a user-centred design perspective. Based on the review results, strengths and weaknesses of the existing studies were identified. Identified strengths included: evidence of the inclusion of multidisciplinary skills and perspectives; user involvement in studies; and the adoption of iterative design practices. Weaknesses included the lack of specificity in the selection of end-users and inconsistent evaluation protocols. The review was concluded by outlining issues and research areas that need to be addressed in the future, including: greater understanding of the effectiveness of sharing data between peers, privacy, and guidelines for designing for behavioural change through mobile phone applications.     

Airborne laser scanning data storage and indexing: state-of-the-art review

While the rapid growth in the availability and quality of airborne laser scanning data offers unprecedented information, it challenges the existing data management and dissemination solutions. Data management has become a bottleneck to effective laser scanning data exploration. This paper documents the state-of-the-art techniques for aerial laser scanning (ALS) data storage and indexing during the post-processing stage. A brief history of laser scanning technology is presented with the intention to offer an overview about the evolution of the technology from the data point of view inclusive of full waveform data management. The key strategies for data handling, including data modelling and indexing, are extensively discussed.     

Content-based representation and retrieval of visual media: A state-of-the-art review

This paper reviews a number of recently available techniques in content analysis of visual media and their application to the indexing, retrieval, abstracting, relevance assessment, interactive perception, annotation and re-use of visual documents.This work was performed while this author was with Institute of Systems Science, Singapore.     

Modelling of stationary and growing cracks in FE framework without remeshing: a state-of-the-art review

The recently developed techniques for modelling cracking within the finite element (FE) framework which use meshes independent of the crack configuration and thus avoid remeshing are reviewed. They combine the traditional FE method with the partition of unity method for modelling individual cracks, intersecting or branching cracks, as well as cracks emanating from holes or other internal interfaces. Numerical integration for the enriched elements, linear dependence and the corresponding solution techniques for the discretized system of equations, as well as the accuracy of the crack tip fields are addressed. Future improvements of the techniques as well as their applications are discussed.     

Magnetohydrodynamic three-dimensional flow of nanofluids with slip and thermal radiation over a nonlinear stretching sheet: a numerical study

A numerical simulation for mixed convective three-dimensional slip flow of water-based nanofluids with temperature jump boundary condition is presented. The flow is caused by nonlinear stretching surface. Conservation of energy equation involves the radiation heat flux term. Applied transverse magnetic effect of variable kind is also incorporated. Suitable nonlinear similarity transformations are used to reduce the governing equations into a set of self-similar equations. The subsequent equations are solved numerically by using shooting method. The solutions for the velocity and temperature distributions are computed for several values of flow pertinent parameters. Further, the numerical values for skin-friction coefficients and Nusselt number in respect of different nanoparticles are tabulated. A comparison between our numerical and already existing results has also been made. It is found that the velocity and thermal slip boundary condition showed a significant effect on momentum and thermal boundary layer thickness at the wall. The presence of nanoparticles stabilizes the thermal boundary layer growth.

     

Recent development in CNC machining of freeform surfaces: A state-of-the-art review

Freeform surfaces, also called sculptured surfaces, have been widely used in various engineering applications. Freeform surfaces are primarily manufactured by CNC machining, especially 5-axis CNC machining. Various methodologies and computer tools have been developed in the past to improve efficiency and quality of freeform surface machining. This paper aims at providing a state-of-the-art review on recent research development in CNC machining of freeform surfaces. This review primarily focuses on three aspects in freeform surface machining: tool path generation, tool orientation identification, and tool geometry selection. For each aspect, first concepts, requirements and fundamental research methods are briefly introduced. The major research methodologies developed in the past decade in each aspect are presented with details. Problems and future research directions are also discussed.     

Research and application of artificial intelligence techniques for wire arc additive manufacturing: a state-of-the-art review

Recent development in the Wire arc additive manufacturing (WAAM) provides a promising alternative for fabricating high value-added medium to large metal components for many industries such as aerospace and maritime industry. However, challenges stemming from the demand for increasingly complex and high-quality products, hinder the widespread adoption of the conventional WAAM method for manufacturing industries. The development of artificial intelligence (AI) techniques may provide new opportunities to upgrade WAAM to the next generation. Hence, this paper provides a comprehensive review of the state-of-the-art research on AI techniques in WAAM. Firstly, we proposed a novel concept of intelligent wire arc additive manufacturing (IWAAM) and revealed the challenges of developing IWAAM. Secondly, an overview of the research progress of applying AI techniques to several aspects of the WAAM process chain, including fabrication process pre-design, online deposition control and offline parameter optimization is provided. Thirdly, the relevant machine learning algorithms, and the knowledge of corresponding AI techniques, are also reviewed in detail. Through reviewing the current research articles, issues of applying AI techniques to the WAAM process are presented and analysed. Finally, future research perspectives in terms of novel AI technique applications and AI technique enhancement are discussed. Through this systematic review, it is expected that WAAM may gradually develop into a smart/intelligent manufacturing technology in the context of Industry 4.0 through the adoption of AI techniques.