Selective Emitters Design and Optimization for Energy Harvesting Using Rectennas

2016 ◽  
Author(s):  
Mehdi Zeyghami ◽  
Philip D. Myers ◽  
D. Yogi Goswami ◽  
Elias Stefanakos
Keyword(s):  
High Efficiency ◽  
Characteristic Length ◽  
High Energy ◽  
Algorithm Optimization ◽  
Selective Emitter ◽  
Design And Optimization ◽  
Attractive Option ◽  
Conversion Efficiencies ◽  
Thermal Sources ◽  
Selective Emitters

Recently, rectennas have drawn attention as an attractive option to harvest radiative thermal energy from the sun and terrestrial thermal sources. In order to achieve the potential high energy conversion efficiencies by this technology, matching conditions between the incident electromagnetic wavelength and the rectenna characteristic length must be satisfied. Therefore, a selective emitter is a key element in high efficiency rectennas. Photonic structures were designed for selective emission using the transfer matrix method and genetic algorithm optimization. Two types of emitters were developed using aluminum as the supporting substrate. This paper presents narrowband selective emitters with a peak emissivity at 9.45 μm made of alternating layers of Al2O3 and SiO2 on a substrate, and broadband selective emitters made of alternating layers of Al2O3 and SiC on a substrate with a high emissivity band between 9.5 μm and 10.5 μm.

scholarly journals Monte Carlo Modeling and Design of Photon Energy Attenuation Layers for >10× Quantum Yield Enhancement in Si-Based Hard X-ray Detectors

Instruments ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 17
Author(s):  
Eldred Lee ◽  
Kaitlin M. Anagnost ◽  
Zhehui Wang ◽  
Michael R. James ◽  
Eric R. Fossum ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Quantum Yield ◽  
Photon Energy ◽  
High Efficiency ◽  
High Energy ◽  
Yield Enhancement ◽  
X Ray ◽  
Simulation Results ◽  
Conversion Efficiencies

High-energy (>20 keV) X-ray photon detection at high quantum yield, high spatial resolution, and short response time has long been an important area of study in physics. Scintillation is a prevalent method but limited in various ways. Directly detecting high-energy X-ray photons has been a challenge to this day, mainly due to low photon-to-photoelectron conversion efficiencies. Commercially available state-of-the-art Si direct detection products such as the Si charge-coupled device (CCD) are inefficient for >10 keV photons. Here, we present Monte Carlo simulation results and analyses to introduce a highly effective yet simple high-energy X-ray detection concept with significantly enhanced photon-to-electron conversion efficiencies composed of two layers: a top high-Z photon energy attenuation layer (PAL) and a bottom Si detector. We use the principle of photon energy down conversion, where high-energy X-ray photon energies are attenuated down to ≤10 keV via inelastic scattering suitable for efficient photoelectric absorption by Si. Our Monte Carlo simulation results demonstrate that a 10–30× increase in quantum yield can be achieved using PbTe PAL on Si, potentially advancing high-resolution, high-efficiency X-ray detection using PAL-enhanced Si CMOS image sensors.

Design and Optimization of Thermal Selective Emitters for High-Efficiency Thermophotovoltaic (TPV) Power Generation

2015 ◽  
Author(s):  
Anil Yuksel ◽  
Alex Heltzel ◽  
John R. Howell
Keyword(s):  
Band Gap ◽  
Conversion Efficiency ◽  
High Efficiency ◽  
Narrow Band ◽  
Low Noise ◽  
Energy Band Gap ◽  
Design And Optimization ◽  
Thermal Emitter ◽  
Selective Emitters ◽  
Sharp Cutoff

Thermophotovoltaic (TPV) devices are popular energy converters due to providing low noise, low thermal-mechanical stresses and portability. The conversion efficiency of TPVs is still low due to mistuned spectral properties between thermal selective emitters and the TPV cell. Using thermal selective emitters that are well-matched to the TPV cell spectrum enhances the conversion efficiency of TPVs. Several thermal selective emitters, composed of 1-D complex multilayer structures with rectangular gratings, have been proposed. Cost, fabrication and stability factors have been major problems for their application on TPV modules. In this paper, a 1-D tungsten thermal emitter is optimized which exhibits close to blackbody emittance near the band-gap of a GaInAsSb TPV cell and sharp cutoff for longer wavelengths. The emitter is at 1200K, and is designed and optimized by modeling triangular grooves to excite localized groove modes which are well-matched to the GaInAsSb TPV cell external quantum efficiency (EQE) for high efficiency energy conversion. We suggest that a quasi-monochromatic, narrow-band and coherent emitter at a frequency near the energy band-gap of the converter is an ideal source to achieve high conversion efficiency.

scholarly journals Development of a Mobile Analytical Chemistry Workstation Using a Silicon Electrochromatography Microchip and Capacitively Coupled Contactless Conductivity Detector

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 239
Author(s):  
Yineng Wang ◽  
Xi Cao ◽  
Walter Messina ◽  
Anna Hogan ◽  
Justina Ugwah ◽  
...  
Keyword(s):  
Capillary Electrochromatography ◽  
High Efficiency ◽  
Device Fabrication ◽  
Capacitively Coupled ◽  
Packaging Design ◽  
Design And Optimization ◽  
Nanofabrication Technique ◽  
On Chip ◽  
Silicon Based ◽  
Rapid Separations

Capillary electrochromatography (CEC) is a separation technique that hybridizes liquid chromatography (LC) and capillary electrophoresis (CE). The selectivity offered by LC stationary phase results in rapid separations, high efficiency, high selectivity, minimal analyte and buffer consumption. Chip-based CE and CEC separation techniques are also gaining interest, as the microchip can provide precise on-chip control over the experiment. Capacitively coupled contactless conductivity detection (C4D) offers the contactless electrode configuration, and thus is not in contact with the solutions under investigation. This prevents contamination, so it can be easy to use as well as maintain. This study investigated a chip-based CE/CEC with C4D technique, including silicon-based microfluidic device fabrication processes with packaging, design and optimization. It also examined the compatibility of the silicon-based CEC microchip interfaced with C4D. In this paper, the authors demonstrated a nanofabrication technique for a novel microchip electrochromatography (MEC) device, whose capability is to be used as a mobile analytical equipment. This research investigated using samples of potassium ions, sodium ions and aspirin (acetylsalicylic acid).

scholarly journals Modeling and Measurement of Thermal Effect in a Flashlamp-Pumped Direct-Liquid-Cooled Split-Disk Nd:LuAG Ceramic Laser Amplifier

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Shengzhe Ji ◽  
Wenfa Huang ◽  
Tao Feng ◽  
Long Pan ◽  
Jiangfeng Wang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Thermal Effects ◽  
Thermal Deformation ◽  
High Energy ◽  
Gain Medium ◽  
Wavefront Aberration ◽  
Experimental Measurements ◽  
Laser Amplifier ◽  
Design And Optimization ◽  
Ceramic Laser

In this paper, a model to predict the thermal effects in a flashlamp-pumped direct-liquid-cooled split-disk Nd:LuAG ceramic laser amplifier has been presented. In addition to pumping distribution, the model calculates thermal-induced wavefront aberration as a function of temperature, thermal stress and thermal deformation in the gain medium. Experimental measurements are carried out to assess the accuracy of the model. We expect that this study will assist in the design and optimization of high-energy lasers operated at repetition rate.

scholarly journals Combination of Dual-Energy X-ray Transmission and Variable Gas-Ejection for the In-Line Automatic Sorting of Many Types of Scrap in One Measurement

2021 ◽  
Vol 11 (10) ◽  
pp. 4349
Author(s):  
Tianzhong Xiong ◽  
Wenhua Ye ◽  
Xiang Xu
Keyword(s):  
High Efficiency ◽  
Nearest Neighbor ◽  
High Energy ◽  
Dual Energy ◽  
Center Of Gravity ◽  
Low Energy ◽  
Identification Accuracy ◽  
Flow Process ◽  
X Ray ◽  
Automatic Sorting

As an important part of pretreatment before recycling, sorting has a great impact on the quality, efficiency, cost and difficulty of recycling. In this paper, dual-energy X-ray transmission (DE-XRT) combined with variable gas-ejection is used to improve the quality and efficiency of in-line automatic sorting of waste non-ferrous metals. A method was proposed to judge the sorting ability, identify the types, and calculate the mass and center-of-gravity coordinates according to the shading of low-energy, the line scan direction coordinate and transparency natural logarithm ratio of low energy to high energy (R_value). The material identification was satisfied by the nearest neighbor algorithm of effective points in the material range to the R_value calibration surface. The flow-process of identification was also presented. Based on the thickness of the calibration surface, the material mass and center-of-gravity coordinates were calculated. The feasibility of controlling material falling points by variable gas-ejection was analyzed. The experimental verification of self-made materials showed that identification accuracy by count basis was 85%, mass and center-of-gravity coordinates calculation errors were both below 5%. The method proposed features high accuracy, high efficiency, and low operation cost and is of great application value even to other solid waste sorting, such as plastics, glass and ceramics.

scholarly journals Siberian Snakes, Figure-8 and Spin Transparency Techniques for High Precision Experiments with Polarized Hadron Beams in Colliders

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 398
Author(s):  
Yaroslav S. Derbenev ◽  
Yury N. Filatov ◽  
Anatoliy M. Kondratenko ◽  
Mikhail A. Kondratenko ◽  
Vasiliy S. Morozov
Keyword(s):  
High Precision ◽  
High Energy Physics ◽  
High Efficiency ◽  
High Energy ◽  
Polarized Beams ◽  
Polarization Control ◽  
Spin Polarized ◽  
High Flexibility ◽  
Spin Flips ◽  
Energy Physics

We present a review of the possibilities to conduct experiments of high efficiency in the nuclear and high energy physics with spin-polarized beams in a collider complex, configuration of which includes Siberian snakes or figure-8 collider ring. Special attention is given to the recently elicited advantageous possibility to conduct high precision experiments in a regime of the spin transparency (ST) when the design global spin tune is close to zero. In this regime, the polarization control is realized by use of spin navigators (SN), which are compact special insertions of magnets dedicated to a high flexibility spin manipulation including frequent spin flips.

FOAMING AND MOISTURE CROSSLINKING OF VINYL TRIETHOXY SILANE GRAFTED ETHYLENE–PROPYLENE–DIENE TERPOLYMER

2022 ◽  
Author(s):  
Zhengwei Lin ◽  
Qinghong Zhang ◽  
Gongliang Wang ◽  
Jie Mao ◽  
Martin Hoch ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Side Reaction ◽  
High Energy ◽  
Expansion Ratio ◽  
Ethylene Propylene ◽  
Foaming Process ◽  
The Matrix ◽  
High Energy Absorption ◽  
Ethylene Propylene Diene Terpolymer

ABSTRACT Moisture crosslinking of polyolefins has attracted increasing attention because of its high efficiency, low cost, and easy processing. However, the crucial shortcoming of moisture crosslinking is that the side reaction of peroxide scorch (precrosslinking) simultaneously occurs in silane grafting. It has been recognized that making peroxide precrosslinking useful is an effective way to broaden the application of moisture crosslinking. A novel foaming process combined with moisture crosslinking is proposed. The matrix of ethylene–propylene–diene terpolymer grafted with silane vinyl triethoxysilane (EPDM-g-VTES) was prepared by melt grafting, with dicumyl peroxide as initiator. Foaming was then carried out with azodicarbonamide (AC) as the blowing agent by making use of precrosslinking. Subsequently, the EPDM-g-VTES foams were immersed in a water bath to achieve moisture crosslinking with dibutyl tin dilaurate as the catalyst. The results showed that VTES was grafted onto EPDM and the EPDM-g-VTES foams were successfully crosslinked by moisture. The EPDM-g-VTES compounds with AC obtained great cells by compression molding with the help of precrosslinking. The mechanical property of the EPDM-g-VTES foam was improved by moisture crosslinking. The moisture-cured foam with 4 wt% AC had an expansion ratio of about three times, which could bear large deformation and showed a high energy-absorption effect.

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