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Resonant square-wave clock generator for low power applications

Power reduction is the main challenge facing circuit designers in their quest to utilize the full performance of new process technologies. A major portion of the power consumed in today's systems is due to the clock generation and distribution. Resonant clocking has been a promising technique to reduce the clock power dramatically. In this paper, a novel resonant clock generator circuit is proposed to reduce the dynamic power used for clock generation by almost 75%. Two configurations of the circuit are presented. The merit of this generator is most obvious in the ease of its implementation

Energy and Water
Circuit Theory and Applications

Communication—convolution-based estimation of supercapacitor parameters under periodic voltage excitations

Supercapacitors are typically used in applications requiring frequent and continuous charging/discharging cycles, but most of the models available in the literature are designed to predict their behavior for a single sequence. In this letter, we show first that the electrical response and metrics of supercapacitors under periodic voltage excitations can generally be obtained using Fourier series analysis and convolution operations of functions derived based on any suitable impedance model. We verified our analysis procedure with simulations using particle swarm optimization, and experiments

Energy and Water
Circuit Theory and Applications

Communication-The Ragone Plot of Supercapacitors under Different Loading Conditions

The power-energy performance of supercapacitors is usually visualized by the Ragone plot of (gravimetric or volumetric) energy density vs power density. The energy is commonly computed from E = CV2/2, and the power from P = E/Δt, which assume RCbased models. In this study, we investigate the energy-power profiles of two commercial supercapacitors discharged with three different types of loads: (i) constant current, (ii) constant power, and (iii) constant resistive load. The energy is computed as per the definition from the time-integral of its instantaneous power, i.e. E(t) = ò p(t)dt with p(t

Energy and Water
Circuit Theory and Applications

Aggrandize efficiency of ultra-thin silicon solar cell via topical clustering of silver nanoparticles

A highly efficient photovoltaic nanocomposite device is demonstrated by fabrication of structural clusters of silver nanoparticles (Ag NPs) on silicon solar cells via a boil deposition method. The efficiency of silicon solar cell was augmented by coating Ag NPs ultra-thin-film deposition on silicon solar cell. Chemically synthesized silver NP's, their consumption on a silicon thin layer and the operation of photovoltaic nanocomposite device were characterized by using several electron probe microscopic pectroscopic and spectrometric techniques viz. x-ray diffraction (XRD), scanning electron

Energy and Water
Circuit Theory and Applications

Investigation of properties limiting efficiency in Cu2ZnSnSe4-based solar cells

We have investigated different nonidealities in Cu2ZnSnSe4-CdS-ZnO solar cells with 9.7% conversion efficiency, in order to determine what is limiting the efficiency of these devices. Several nonidealities could be observed. A barrier of about 300 meV is present for electron flow at the absorber-buffer heterojunction leading to a strong crossover behavior between dark and illuminated current-voltage curves. In addition, a barrier of about 130 meV is present at the Mo-absorber contact, which could be reduced to 15 meV by inclusion of a TiN interlayer. Admittance spectroscopy results on the

Energy and Water
Circuit Theory and Applications
Software and Communications

Hierarchical proactive caching for vehicular ad hoc networks

Recently, emerging vehicular applications are increasing the demand of vehicles which form significant burdens on network backhaul and represents a cause to the quality of experience (QoE) decay of the vehicular users. Proactive caching is a promising technique to mitigate the load on core networks by caching some of the expected data items. This work proposes a hierarchical proactive caching scheme which jointly considers caching in vehicles and roadside units (RSUs). Minimization of the vehicle communication latency is the main objective of our study. The optimization problem is formulated

Energy and Water
Circuit Theory and Applications
Software and Communications

Recent Trends of Recycled Carbon-Based Nanomaterials and Their Applications

“There’s Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics” said Richard Feynman in 1959, this lecture opened the way to the new field of science which we know today as nanotechnology. Materials’ manipulation at a very small size, ranges from 1 to 100 nm (nanoworld or the nano-edge) is well-known as nanotechnology. Since then, a lot of investigations and research were devoted by many researchers around the globe to keep an eye on the different properties and behavior of nanomaterials. Materials with at least one nanoscale dimension are called nanomaterials that have

Energy and Water
Agriculture and Crops

A system model for green manufacturing

Manufacturing systems evolution is afunction in multiple external and internal factors. With today's global awareness of environmental risks as well as the pressing needs to compete through efficiency, manufacturing systems are evolving into a new paradigm. This paper presents a system model for the new green manufacturing paradigm. The model captures various planning activities to migrate from a less green into a greener and more eco-efficient manufacturing. The various planning stages are accompanied by the required control metrics as well as various green tools in an open mixed architecture

Energy and Water
Software and Communications
Agriculture and Crops

Layer-by-layer preparation and characterization of recyclable nanocomposite (CoxNi1−xFe2O4; X = 0.9/SiO2/TiO2)

Titanium dioxide (TiO2) nanocomposites have been extensively employed in many fundamental optoelectronic and photocatalytic applications due to their outstanding optical, electronic and chemical properties. In the present work, we introduce a simple layer-by-layer approach to design a magnetic TiO2 nanocomposite that could be easily recycled using an external magnetic field without affecting its quantum efficiency. The crystallinity, size, surface area, stability, morphology, purity and other optical, thermal and magnetic properties of the composite have been investigated. Surface topology

Energy and Water
Agriculture and Crops
Mechanical Design

Bio-composite Thermal Insulation Materials Based on Banana Leaves Fibers and Polystyrene: Physical and Thermal Performance

Thermal insulators have a crucial role in reducing the operational building energy. They are commonly fabricated from petrochemical materials that mostly cause negative environmental impacts. This study aims to develop banana leaves-polystyrene composites (BL-PS) as a sustainable and low-cost thermal insulator. The BL powder was mixed with PS in different weight ratios (90:10, 80:20, 70:30, and 60:40). Thermal conductivity, electrical conductivity, SEM, XRD, FTIR, TGA, and DSC were carried out on BL and BL-PS composites that were prepared with 10 wt.% of PS powder (BL-PS1) and 30 wt.% of PS

Energy and Water
Agriculture and Crops
Mechanical Design