With the great development of theory, experiment, and manipulation of micro/nanoscale thermal radiation, several advanced applications emerge and show promising prospects in high-efficiency energy harvest/conversion such as angular/spectral selective or wideband absorber, thermophotovoltaics, or heat management implements such as radiative cooling, thermal camouflage, cloaking, and illusion. This chapter will give a brief introduction of these state-of-art technologies on the basis of theory of micro/nanoscale thermal radiation.

In this chapter, a summary of numerical algorithms solving the radiative transfer equation (RTE) is presented. These algorithms could be roughly classified into two categories. The one is ray-tracing methods, including the Zone method, Monte Carlo method, and discrete transfer method. The stochastic approach of Monte Carlo codes is widely used, since its flexible applicability to arbitrary multidimensional configurations. The others are methods based on the discretization of the differential form of RTE, including the spherical harmonics method, discrete ordinates method, and finite volume method.

At micro/nanoscale, the general principles of the thermal radiation are failed to solve or explain the majority of radiative problems or phenomena. This chapter will first point out the limitations and reasons of the general principles of thermal radiation by introducing a typical example. Then, some basic concepts, including the role of energy carriers such as photons, electrons, and phonon will be introduced first, followed by the brief introduction of the corresponding governing equations and the influence mechanism in radiative properties. Next, we would like to give a fundamental framework and chart review from macro- to nanoscalethermal radiation, aiming to make the relation and difference between macro- and nanothermal radiation more distinct. Finally, the development of micro/nanoscale thermal radiation in the last decades will be summarized as well.

The radiative transfer equation (RTE) is the governing equation of radiation propagation in participating media, which plays a central role in the analysis of radiative transfer in gases, semitransparent liquids and solids, porous materials, and particulate media, and is important in many scientific and engineering disciplines. This chapter will give a detailed introduction of the RTE. The microphysical derivation and the physical meaning of the relating quantities will be given. Besides, the relationship between the RTE and Maxwell’s equation will also be discussed and deduced as well, to build a comprehensive understanding of the RTE.

Thermal radiation is a ubiquitous aspect of nature, and this subject has developed for several centuries. In order to build a framework of macroscale thermal radiation, this chapter will give brief introductions of some fundamental theories and definitions of basic concepts of thermal radiation, such as blackbody radiation, radiative interactions at a surface, and radiative exchange between two or more surfaces. Besides, gas radiation as an important direction of thermal radiation will be introduced, including the molecular radiation theory, some gas spectral models, and some useful results in engineering applications.

Macrothermal radiation theory and analysis methods have been widely used in several real applications, such as heat transfer processes in the industrial boiler, radiant heat exchanger design, solar-thermal conversion in solar power plants, and so on. This chapter will cover the applications associated with macrothermal properties control, and some typical application examples will be given, hoping to offer a guidance in engineering applications.

This chapter focuses on experimental techniques in macroscale thermal radiation. The contents mainly involve the Fourier transform infrared spectrometer, the UV-Vis-NIR spectrophotometer, and the bidirectional reflectance distribution function (BRDF) instrument. We will review some outstanding experiments performed by different research groups for measuring the properties of macroscale thermal radiation. This chapter can be served as a guideline for researchers to design the experimental setups.

This chapter is intended to review concepts that the reader has some familiarity with and introduce high level descriptions of linear marine systems analysis. An initial discussion on the similarity between mechanical vibration equations of motion and marine dynamical systems is made. Mechanical vibrations are defined as vibrations in the absence of fluids. Examples of static and dynamic coupling between the various modes of motion or degrees of freedom are presented. The differences between frequency domain and time domain representations are given by introducing the concept of response amplitude operators (RAO’s). Complex arithmetic and linear, second order differential equations are briefly reviewed. Two examples of mechanical vibrations that are relevant to marine dynamics are developed and solved. The first example has to do with base excitation, similar to what a high speed planing craft may experience in long waves. The second example addresses one method for vibration isolation/suppression, that may, or may not, be useful in shock/impact mitigation schemes.

Previous chapters presented linear models for responses of marine systems in regular, harmonic waves and various probabilistic properties of random processes, e.g. ocean waves. This chapter combines the two topics - a system’s deterministic response in the frequency domain and the statistics of that system’s random response when excited by a random, irregular sea. Several models for ocean wave spectra are presented and input/output relations for linear systems subject to stochastic excitation developed. The ocean wave environment is described by a single-sided wave spectrum based on various empirical formulae: P-M spectrum (single parameter, wind speed or significant wave height for the North Atlantic); ISSC spectrum (two parameter, significant crossing period and wave height); JONSWAP spectrum (six parameter, fetch limited, typical of the North Sea); and the Ochi six parameter spectrum (combined wind and swell). Short crested seas are defined and their effects discussed. The output spectrum of a linear system subject to stochastic input is derived and its Gaussian PDF given. By invoking a narrow banded assumption, PDF’s of the output follow the Rayleigh most probable extremes.

This section lays the foundation for the analysis of random marine dynamics. A platform’s dynamics, which result from excitation due to irregular waves, can generally by expressed in a Fourier series - a consequence of linearity and the principal of linear superposition. Fourier representation, either through Fourier series or Fourier transforms, allows for frequency or time domain analysis, both of which are developed in this chapter. The frequency domain representation implies a harmonic solution in time. Consequently, the system of second order ordinary differential equations with constant coefficients become a set of simultaneous linear algebraic equations whose solutions are the complex motion amplitudes. This system of equations represents the response to harmonic forcing and does not include transient behavior associated with initial conditions. A time domain representation of floating bodies requires a means to include system memory effects. These memory effects are modeled by convolution integrals in the equations of motion where the kernel function in the convolution integral is related to the Fourier cosine transform of the damping coefficient of the floating body.

A distinguishing factor of marine dynamics is the presence of the air-water interface. In order to determine the dynamic fluid forces acting on floating bodies - the wave exciting forces and the radiation forces (i.e. added mass and damping) - in addition to the hydrostatic forces, a lower order model of water waves based on the velocity potential and a linearized form of Bernoulli’s equation is given. The air-water interface is defined by two boundary conditions: kinematic and dynamic boundary conditions. Examining limits of the free surface boundary conditions allows a limiting process in the estimation of fluid added mass without having to solve a free surface boundary value problem. A low order model of plane progressive waves is simply a harmonic function in the lateral plane multiplied by an exponentially decaying function in the vertical coordinate. Application of the linear free surface conditions yields the important dispersion relation - a relation between the temporal wave frequency and the spatial wave frequency.

The presentation is necessarily brief and references for a more comprehensive development are listed.