There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

This Review explains the concept of dissipative solitons and their application to high-energy mode-locked fibre laser cavities. Dynamics and effects such as dissipative soliton ‘explosions’ and ‘rain’ are summarized, and an outlook of the field is also provided.

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Dissipative solitons for mode-locked lasers

DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

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Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

The Internet of Things (IoT) is the next era of communication. Using the IoT, physical objects can be empowered to create, receive, and exchange data in a seamless manner. Various IoT applications focus on automating different tasks and are trying to empower the inanimate physical objects to act without any human intervention. The existing and upcoming IoT applications are highly promising to increase the level of comfort, efficiency, and automation for the users. To be able to implement such a world in an ever-growing fashion requires high security, privacy, authentication, and recovery from attacks. In this regard, it is imperative to make the required changes in the architecture of the IoT applications for achieving end-to-end secure IoT environments. In this paper, a detailed review of the security-related challenges and sources of threat in the IoT applications is presented. After discussing the security issues, various emerging and existing technologies focused on achieving a high degree of trust in the IoT applications are discussed. Four different technologies, blockchain, fog computing, edge computing, and machine learning, to increase the level of security in IoT are discussed.

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A Survey on IoT Security: Application Areas, Security Threats, and Solution Architectures

Interrelation between various branches of stable solitons in dissipative systems - conjecture for stability criterion

Summary form only given. A major problem with standard step index fibers is their inefficiency in coupling to integrated optical devices and waveguides, semiconductor devices such as laser diodes, other fiber waveguides with different properties, etc. Coupling losses are mainly caused by mismatch of the modal field distributions, and partly by changes in wave impedance. It is known that holey fiber may be designed to remain single mode over an extremely wide range of wavelengths. It follows that a fixed wavelength the size of the waveguide may be scaled by an appreciable factor and remain single mode. Consequently, adiabatically tapered holey fibers may be used to perform significant scaling of guided mode-field distributions with low loss. The effective index of the guided mode may also vary significantly. We have derived general guidelines for adiabatic taper design, and calculated the mode-field distributions at both ends of an optimally shaped taper.

Tapered holey fibers for spot size and numerical aperture conversion

Distribution of solar pyrolysis products and product gas composition produced from agricultural residues and animal wastes at different operating parameters

Solar assisted catalytic pyrolysis of chicken-litter waste with in-situ and ex-situ loading of CaO and char

Strategic use of domestic battery storage in households with a V2G-capable electric vehicle and photovoltaic generation is shown to be capable of shaving the peak loading on the electricity distribution grid under realistic operating conditions by up to 37%. The additional degree of freedom provided by combining the EV and domestic storage is shown to enable additional reductions in peak grid load. A smart control algorithm is described for coordinating the system components to reduce peak grid load and improve power quality.

Graham Town

Papers

Interrelation between various branches of stable solitons in dissipative systems - conjecture for stability criterion

Tapered holey fibers for spot size and numerical aperture conversion

Distribution of solar pyrolysis products and product gas composition produced from agricultural residues and animal wastes at different operating parameters

Solar assisted catalytic pyrolysis of chicken-litter waste with in-situ and ex-situ loading of CaO and char

Improved peak shaving in grid-connected domestic power systems combining photovoltaic generation, battery storage, and V2G-capable electric vehicle