scholarly journals Enhancing positron production using front surface target structures

2021 ◽  
Vol 118 (9) ◽  
pp. 094101
Author(s):  
S. Jiang ◽  
A. Link ◽  
D. Canning ◽  
J. A. Fooks ◽  
P. A. Kempler ◽  
...  
Keyword(s):  
Front Surface ◽  
Positron Production

scholarly journals Enhancing Positron Production using Front Surface Target Structures

2020 ◽  
Author(s):  
Sheng Jiang ◽  
Anthony Link ◽  
Dave Canning ◽  
Julie Fooks ◽  
Paul Kempler ◽  
...  
Keyword(s):  
Large Scale ◽  
Front Surface ◽  
Substantial Effect ◽  
Positron Energy ◽  
Particle In Cell ◽  
Laser Plasma Interactions ◽  
High Intensity Laser ◽  
Scale Particle ◽  
Positron Production

Abstract We report the first experimental results and simulations that demonstrate a substantial effect of large-scale front-surface target structures on high-intensity laser-produced positrons. Specifically, as compared to a flat target under nominally the same laser conditions, an optimized Si microwire array target yielded a near 100% increase in the laser-to-positron conversion efficiency and produced a 10 MeV increase in positron energy. Full-scale particle-in-cell simulations that modeled the entire positron production and transport process starting from laser-plasma interactions provided additional insight into the beneficial role of target structuring. The agreement between experimental and simulated spectra suggests future target structure optimization for desired positron sources.

Main Provisions Of The Concept Of Technology Of Diamond Cutting And Drilling Of Building Structures

2019 ◽  
pp. 59-63
Keyword(s):  
Combustion Engine ◽  
Front Surface ◽  
The Body ◽  
Building Structures ◽  
Diamond Cutting ◽  
Variable Diameter ◽  
Diamond Drilling ◽  
Single Structure ◽  
New Construction ◽  
Non Destructive

The main provisions of the concept of technology of diamond cutting and drilling of building structures are considered. The innovativeness of the technology, its main possibilities and advantages are presented. Carrying out works with the help of this technology in underwater conditions expands its use when constructing and reconstructing hydraulic structure. The use of diamond drilling equipment with motors equipped with an internal combustion engine is considered. Drilling holes with a variable diameter during the reconstruction of the runways of airfields makes it possible to combine the landing mats into a single structure. The ability to cut inside the concrete mass, parallel to the front surface, has no analogues among the methods of concrete treatment. The use of this technology for producing blind openings in the body of concrete without weakening the structure is also unique. Work with precision quality in cutting and diamond drilling of concrete and reinforced concrete was noted by architects and began to be implemented in the manufacture of inter-room and inter-floor openings. Non-destructive approach to the fragmentation of building structures allows them to be reused. The technology of diamond cutting and drilling is located at the junction of new construction, repair, reconstruction of buildings and structures, and dismantling of structures. Attention is paid to the complexity and combinatorial application of diamond technology. Economic efficiency and ecological safety of diamond technology are presented. The main directions of further research for the development of technology are indicated.

Multiobjective optimization of hard coating parameters designing for damping of the bladed disk

2017 ◽  
Vol 232 (9) ◽  
pp. 1609-1619 ◽  
Author(s):  
Yugang Chen ◽  
Jingyu Zhai ◽  
Qingkai Han
Keyword(s):  
Pareto Front ◽  
Engineering Application ◽  
Front Surface ◽  
Model Material ◽  
Superior Performance ◽  
Hard Coating ◽  
Damping Capacity ◽  
Nsga Ii ◽  
Bladed Disk ◽  
Design Variables

In this paper, the damping capacity and the structural influence of the hard coating on the given bladed disk are optimized by the non-dominated sorting genetic algorithm (NSGA-II) coupled with the Kriging surrogate model. Material and geometric parameters of the hard coating are taken as the design variables, and the loss factors, frequency variations and weight gain are considered as the objective functions. Results of the bi-objective optimization are obtained as curved line of Pareto front, and results of the triple-objective optimization are obtained as Pareto front surface with an obvious frontier. The results can give guidance to the designer, which can help to achieve more superior performance of hard coating in engineering application.

Brilliant attosecond γ-ray emission and high-yield positron production from intense laser-irradiated nano-micro array

2021 ◽  
Vol 28 (2) ◽  
pp. 023110
Author(s):  
Liang-qi Zhang ◽  
Shao-dong Wu ◽  
Hai-rong Huang ◽  
Hao-yang Lan ◽  
Wei-yuan Liu ◽  
...  
Keyword(s):  
Intense Laser ◽  
High Yield ◽  
Micro Array ◽  
Γ Ray ◽  
Positron Production

Biodynamic Modeling of a Pedestrian Impact With a Rigid Frontal Guard of a Utility Vehicle

2010 ◽  
Author(s):  
Rasoul Moradi ◽  
Chandrashekhar K. Thorbole ◽  
Michael McCoy ◽  
Hamid M. Lankarani
Keyword(s):  
Front Surface ◽  
Body Region ◽  
Computational Technique ◽  
Surface Model ◽  
Published Data ◽  
Factors Affecting ◽  
Light Trucks ◽  
Accident Data ◽  
Facet Surface ◽  
The Impact

Accident data reveals that in most pedestrian accidents, the pedestrian head and lower extremity are vulnerable to serious injuries. The vehicle front geometry profile as well as the impact speed are important factors affecting the pedestrian kinematics and injury potential. In the US, accident data also shows that the fatality rate for pedestrian/light trucks and vans (LTV) impact is greater than that for the pedestrian/passenger-car impact. Addition of a front guard on light trucks and sports utility vehicles to mitigate damage during off-road activity or to provide mounting points for extra lights, makes the pedestrian more vulnerable to the impact. In this paper, a computational technique is utilized to study the influence of the added front guard on the impacted pedestrian. A CAD model of a typical commercial frontal guard is developed and converted into a rigid facet model, and attached to the vehicle front. The validated standing dummy model in the MADYMO code is used to simulate a pedestrian, and the rigid facet-surface model of a pickup truck is used to generate a vehicle front surface. This computational model is validated by comparing the pedestrian kinematics with the published data. This study demonstrates that the pedestrian mid body region is more vulnerable with the addition of guard on the vehicle. The result from this study facilitates a better understanding of a guard design and its geometry profile as required to protect vulnerable road users.

scholarly journals Influence of the Front Surface Passivation Quality on Large Area n-Type Silicon Solar Cells with Al-Alloyed Rear Emitter

2011 ◽  
Vol 8 ◽  
pp. 487-492 ◽  
Author(s):  
F. Book ◽  
T. Wiedenmann ◽  
G. Schubert ◽  
H. Plagwitz ◽  
G. Hahn
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Front Surface ◽  
Silicon Solar Cells ◽  
Large Area ◽  
Type Silicon

COMBINED EFFECT OF MECHANICAL GROOVING AND STAIN-ETCHED SURFACE ON OPTICAL AND ELECTRICAL PROPERTIES OF CRYSTALLINE SILICON SUBSTRATES

2014 ◽  
Vol 21 (03) ◽  
pp. 1450041 ◽  
Author(s):  
AHMED ZARROUG ◽  
LOTFI DERBALI ◽  
RACHID OUERTANI ◽  
WISSEM DIMASSI ◽  
HATEM EZZAOUIA
Keyword(s):  
Crystalline Silicon ◽  
Light Trapping ◽  
Front Surface ◽  
Minority Carrier Lifetime ◽  
Combined Effect ◽  
Machining Process ◽  
Silicon Substrates ◽  
Textured Surface ◽  
Crystalline Silicon Solar Cell ◽  
Simple Method

This paper investigates the combined effect of mechanical grooving and porous silicon (PS) on the front surface reflectance and the electronic properties of crystalline silicon substrates. Mechanical surface texturization leads to reduce the cell reflectance, enhance the light trapping and augment the carrier collection probability. PS was introduced as an efficient antireflective coating (ARC) onto the front surface of crystalline silicon solar cell. Micro-periodic V-shaped grooves were made by means of a micro-groove machining process prior to junction formation. Subsequently, wafers were subjected to an isotropic potassium hydroxide ( KOH ) etching so that the V-shape would be turned to a U-shape. We found that the successive treatment of silicon surfaces with stain-etching, grooving then alkaline etching enhances the absorption of the textured surface, and decreases the reflectance from 35% to 7% in the 300–1200 nm wavelength range. We obtained a significant increase in the overall light path that generates the building up of the light trapping inside the substrate. We found an improvement in the illuminated I–V characteristics and an increase in the minority carrier lifetime τeff. Such a simple method was adopted to effectively reinforce the overall device performance of crystalline silicon-based solar cells.

scholarly journals A Study of the Electrical Output and Reliability Characteristics of the Crystalline Photovoltaic Module According to the Front Materials

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 163
Author(s):  
Jong Rok Lim ◽  
Woo Gyun Shin ◽  
Chung Geun Lee ◽  
Yong Gyu Lee ◽  
Young Chul Ju ◽  
...  
Keyword(s):  
Surface Film ◽  
Front Surface ◽  
Photovoltaic System ◽  
Photovoltaic Module ◽  
Reliability Test ◽  
Tempered Glass ◽  
Characteristic Analysis ◽  
Pv Module ◽  
Reliability Characteristics ◽  
Electrical Output

In recent years, various types of installations such as floating photovoltaic (PV) and agri-voltaic systems, and BIPV (building integrated photovoltaic system) have been implemented in PV systems and, accordingly, there is a growing demand for new PV designs and materials. In particular, in order to install a PV module in a building, it is important to reduce the weight of the module. The PV module in which low-iron, tempered glass is applied to the front surface, which is generally used, has excellent electrical output and reliability characteristics; however, it is heavy. In order to reduce the weight of the PV module, it is necessary to use a film or plastic-based material, as opposed to low-iron, tempered glass, on the front surface. However, if a material other than glass is used on the front of the PV module, various problems such as reduced electrical output and reduced reliability may occur. Therefore, in this paper, a PV module using a film instead of glass as the front surface was fabricated, and a characteristic analysis and reliability test were conducted. First, the transmittance and UV characteristics of each material were tested, and one-cell and 24-cell PV modules were fabricated and tested for electrical output and reliability. From the results, it was found that the transmittance and UV characteristics of the front material were excellent. In addition, the electrical output and reliability test results confirmed that the front-surface film was appropriate for use in a PV module.

scholarly journals Ultra-bright γ-ray emission and dense positron production from two laser-driven colliding foils

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Han-Zhen Li ◽  
Tong-Pu Yu ◽  
Jin-Jin Liu ◽  
Yan Yin ◽  
Xing-Long Zhu ◽  
...  
Keyword(s):  
Γ Ray ◽  
Positron Production
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