Preface

**Chapter 9 155**

Effective Parameters on Increasing Efficiency of Microscale Heat Sinks

*by Yousef Alihosseini, Amir Rezazad Bari and Mehdi Mohammadi*

and Application of Liquid Cooling in Real Life

**II**

Both microfluidics and nanofluids are rapidly growing technologies that have emerged as multidisciplinary research fields. The impact and importance of these two technologies can be manifested from their tremendous potentials and diverse applications such as virus detection, cell manipulation and separation, 3D printing, anticancer drug screening, advanced thermal management, and energy harvesting and storage. This book covers eclectic areas of these emerging technologies starting from their fundamentals to development to applications and it is composed of nine chapters that are organized into two sections: one related to microfluidics and the other on nanofluids and cooling.

The first chapter presents an overview of advances in both microfluidic and nanofluid technologies. This chapter provides the overall information and discusses the progress of these technologies. In addition to reviewing their key features, their applications and challenges are also highlighted.

In the second chapter, we discuss the applications of microfluidic devices specifically developed for the investigation of time-resolved analysis of growth kinetics and the structural evolution of nanoparticles and nanofibers. Focus is placed on the design considerations required for spectrometry and SAXS analysis. This chapter also discusses the use of these devices for time-resolved research.

The third chapter demonstrates commonly used manufacturing technologies and the process chain for prototyping and mass production of microfluidic chips. It details various types of rapid prototyping technologies besides presenting some important research findings. It also provides good guidance from processing materials and method selection for chip production to end-users.

A review of microfluidic flow sensing approaches is presented in Chapter 4. It covers numerous aspects including currently available products, microfluidic flow sensing technologies, major factors impacting flow metrology, and prospective sensing approaches for future microfluidic flow sensing.

Chapter 5 provides a comprehensive review of the fabrication of circular and rectangular cross-section channels of microfluidic devices using micromilling process. Various process and machining parameters are also discussed in this chapter.

The application of micromixers for wastewater treatment and an assessment of their life cycle are presented in Chapter 6. Six different micromixer designs and an evaluation of the performance of each in the treatment of wastewater are discussed. Their performance in terms of environmental impact was assessed through the life cycle assessment (LCA) methodology.

In the second section of this book, three contributions to nanofluids and cooling are included. The first one (Chapter 7) is on the fundamentals and applications of solar thermal conversion of plasmonic nanofluids. It summarizes the preparation

methods of plasmonic nanofluids and reviews the solar absorption performance of these nanofluids based on the theoretical and experimental design.

The recent advancements of nanocomposite and nanofluids toward sustainable carbon capture, utilization, and storage are presented in Chapter 8. This chapter focuses primarily on nanomaterial applications for both fossil and renewable energies.

The last chapter deals with the effective parameters for increasing the efficiency of heat sinks and the application of liquid cooling in real life. Recent advances in developing an efficient heat sink including different parameters like geometry and flow parameters are reviewed. It also highlights the current gap between academic research and industry.

The book is expected to be a source of information for different communities including students, researchers, manufacturers, academicians, and professionals of these fields.

I would like to thank all the authors for their high-quality contributions and the publishing team for their cooperation and support.

I dedicate this book to my parents and siblings for their sacrifices and support. I owe my success to them.

> **S. M. Sohel Murshed** Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal

**Chapter 1**

Technologies

*S.M. Sohel Murshed*

**1. Introduction**

devices and systems.

Introductory Chapter: An

Overview of Advances in

Microfluidics and Nanofluids

Both microfluidic and nanofluids are rapidly growing and hugely potential technologies which emerged as multidisciplinary research fields. While microfluidic technology began with the development of the first lab-on-a chip in 1979 microfluidic research had its first step forward only when Manz introduced the idea of μ-TAS (Micro total analysis systems) in 1990 [1]. Other main timelines of the development of microfluidic technology include introduction of microfluidics in cell biology and biochemistry in 1994, employing PDMS (polydimethylsiloxane) in microchips production in 1998, introduction of digital microfluidics in 2000, investigations on microfluidics cell culture systems in 2004, development of organon-chip technology between 2005 and 2010, emergence of paper-based microfluidics in 2007, application of 3D printing in microfluidic technology in 2010 and the latest development of microfluidics for theranostics between 2012 and 2015 [2, 3]. Microfluidic technology deals with small amounts (i.e., microliter or nanoliter) of fluids (liquids and gases) in micron or sub-micron size devices/systems/geometries. Microfluidics is a very popular research field which can be evidenced from the rapid growth of numbers of publications on this topic (**Figure 1**). Year-wise publication data on microfluidics for the past two decades (data obtained by searching topic: "microfluidic" in Web of Sciences on 10th May 2021) are presented in **Figure 1**. The impact and importance of microfluidic technology can be manifested from its diverse real-world applications ranging from virus detection and bioanalytical, cell manipulation and separation, 3D printing, paper microfluidics to anticancer drug screening as highlighted in the following section. The advantages of microfluidics include very small quantity (e.g., microliter) of sample or reagent usage, contamination risk reduction, low cost (e.g., for analysis/diagnosis), automation, enhanced sensitivity, accuracy and reliability. Although different materials have been used, PDMS is currently the most widely used material for the fabrication of microfluidic

On the other hand, nanofluids, which is a new class of heat transfer fluids coined in early 1990's [4, 5] have also attracted tremendous attention from the researchers due to their enhanced thermophysical properties, potential benefits, and numerous applications [6–9]. **Figure 1** also shows publication records on nanofluids during the last two decades and the number of publications on nanofluids (search by the topic: Nanofluids) increases exponentialy. It is to note that nanofluid is a much smaller
