scholarly journals Hotter electrons and ions from nano-structured surfaces

2008 ◽  
Vol 26 (2) ◽  
pp. 259-264 ◽  
Author(s):  
S. Bagchi ◽  
P. Prem Kiran ◽  
M.K. Bhuyan ◽  
S. Bose ◽  
P. Ayyub ◽  
...  
Keyword(s):  
Average Energy ◽  
Intense Laser ◽  
Plasma Expansion ◽  
Structured Surfaces ◽  
Particle Generation ◽  
Structured Surface ◽  
Expansion Mechanism ◽  
Electrons And Ions ◽  
The Impact ◽  
Present Understanding

AbstractThe impact of nano-structured surfaces on particle generation from ultrashort intense laser produced plasmas is presented over an intensity range of 1015–1017 Wcm−2. The nano-structured surface evidently produces hotter plasma but does not lead to the generation of hotter ions, a counterintuitive result based on present understanding of plasma expansion mechanism. Although the total ion flux and energy is more in the case of structured surfaces, the average energy of the projectiles is found to be lower than that from polished surfaces. The nano-structured surface shows preferential enhancement of lower energy ions and an intensity dependent divergence of the ejected particles.

scholarly journals Investigation of the Impact of Micro-Structuring on the Bonding Performance of Beechwood (Fagus Sylvatica L.)

Forests ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 113
Author(s):  
Destin Bamokina Moanda ◽  
Martin Lehmann ◽  
Peter Niemz
Keyword(s):  
Bond Strength ◽  
Waiting Time ◽  
Type I ◽  
Bond Quality ◽  
Structured Surfaces ◽  
Structured Surface ◽  
Bonding Performance ◽  
Delamination Resistance ◽  
Micro Structuring ◽  
The Impact

Although glueing softwood is well mastered by the industry, predicting and controlling bond quality for hardwood is still challenging after years of research. Parameters such as the adhesive type, resin–hardener ratio, and the penetration behaviour of the wood are determinants for the bond quality. The aim of this work was to assess to what extent the glueing behaviour of beechwood can be improved by using structural planing. The different surfacing methods were characterised by their roughness. The bond strength of the micro-structured surfaces was determined according to EN 302-1, and the delamination resistance was tested as indicated by EN 302-2 for type I adhesives. Micro-structured surfaces were compared with different surfaces (generated by surfacing methods such as dull/sharp planing and sanding). In dry test conditions, all surfacing methods gave satisfying results. In the wet stage, the bond strength on the finer micro-structured surface slightly outperformed the coarse structure surface. For the delamination resistance, a clear improvement could be observed for melamine-formaldehyde-bonded specimens since, when using the recommended amount of adhesive, micro-structured surfaces fulfilled the requirements. Nevertheless, structural planing cannot lead to a reduction in the applied grammage since no sample with a smaller amount fulfilled EN 302-2 requirements even by observing the recommended closed assembly waiting time. Adhesion area enlargement of the micro-structuring is minor. The good delamination performance without waiting time (CAT) is not caused by surface enlargement, since finer micro-structured surface with negligible area increase and delivered even better delamination resistance. Subsurface analysis should be carried out to thoroughly investigate this phenomenon.

scholarly journals ZTC bias point of advanced fin based device: The importance and exploration

2015 ◽  
Vol 28 (3) ◽  
pp. 393-405 ◽  
Author(s):  
Sushanta Mohapatra ◽  
Kumar Pradhan ◽  
Prasanna Sahu
Keyword(s):  
Power Dissipation ◽  
Temperature Compensation ◽  
Performance Metrics ◽  
Zero Temperature ◽  
Sweet Spot ◽  
Static Power ◽  
20 Nm ◽  
Bias Point ◽  
The Impact ◽  
Present Understanding

The present understanding of this work is about to evaluate and resolve the temperature compensation point (TCP) or zero temperature coefficient (ZTC) point for a sub-20 nm FinFET. The sensitivity of geometry parameters on assorted performances of Fin based device and its reliability over ample range of temperatures i.e. 25?C to 225?C is reviewed to extend the benchmark of device scalability. The impact of fin height (HFin), fin width (WFin), and temperature (T) on immense performance metrics including on-off ratio (Ion/Ioff), transconductance (gm), gain (AV), cut-off frequency (fT), static power dissipation (PD), energy (E), energy delay product (EDP), and sweet spot (gmfT/ID) of the FinFET is successfully carried out by commercially available TCAD simulator SentaurusTM from Synopsis Inc.

scholarly journals Physical handsheet properties of pulp furnishes containing attritor-treated fibers

TAPPI Journal ◽  
2017 ◽  
Vol 16 (01) ◽  
pp. 9-15
Author(s):  
David Knox ◽  
Peter W. Hart ◽  
Humphrey Moynihan ◽  
Nichole Kilgore
Keyword(s):  
Small Particle ◽  
Pulp Fibers ◽  
Processing Methods ◽  
Particle Generation ◽  
Cellulosic Fibers ◽  
The Past ◽  
Dry Processing ◽  
Lack Of Information ◽  
Wet Processing ◽  
The Impact

Several articles have been published during the past 30 years on different methods to produce micro- to nanosize cellulose particles from pulp. Unfortunately, a general lack of information exists on the impact of differing manufacturing process methods upon the product properties obtained from these differing methods. Literature data show that wet processing of small-sized cellulosic fibers generates handsheets with approximately equal or higher density and modulus of elasticity than controls for a given amount of added microcellulose. The current work evaluated small particle generation from pulp fibers via dry processing methods and compared the physical properties of dry versus wet processed particles. Dry processing to obtain microcellulose gave considerably lower sheet density and modulus as compared with wet processed microcellulose. The lower modulus can be compensated for by refining base fibers more aggressively to obtain higher density and higher modulus sheets. Dry processing methods for making microcellulose and their impact on final board properties, including modulus and smoothness, will be discussed.

Numerical Study on Influence of Joint Characters on Rock Mechanical Parameters

2011 ◽  
Vol 201-203 ◽  
pp. 2909-2912
Author(s):  
Yan Feng Feng ◽  
Tian Hong Yang ◽  
Hua Wei ◽  
Hua Guo Gao ◽  
Jiu Hong Wei
Keyword(s):  
Rock Mass ◽  
Compression Strength ◽  
Numerical Study ◽  
Process Analysis ◽  
Failure Process ◽  
Deformation Modulus ◽  
Rock Joints ◽  
Structured Surfaces ◽  
Trace Length ◽  
The Impact

Rock mass is the syntheses composed of kinds of structure and structured surfaces. The joint characters is influencing and controlling the rock mass strength, deformation characteristics and rock mass engineering instability failure in a great degree. Through using the RFPA2D software, which is a kind of material failure process analysis numerical methods based on finite element stress analysis and statistical damage theory, the uniaxial compression tests on numerical model are carried, the impact of the trace length of rock joints and the fault throws on rock mechanics parameters are studied. The results showed that with the gradual increase of trace length,compression strength decreased gradually and its rate of variation getting smaller and smaller, the deformation modulus decreased but the rate of variation larger and larger; with the fault throws increasing, the compression strength first increases and then decreases, when the fault throw is equal to the trace length, the deformation modulus is the largest. When the joint trace length is less than the fault throw, the rate of the deformation modulus is greater than that of trace length, but the deformation modulus was not of regular change.

Impact of Storage Integrated Solar Photovoltaics (PV) Power System on Utility Peak Loads

2011 ◽  
Author(s):  
K. Agyenim-Boateng ◽  
R. F. Boehm
Keyword(s):  
Large Scale ◽  
Peak Load ◽  
Average Energy ◽  
Transient Behavior ◽  
Climatic Conditions ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Pv System ◽  
Grid Load ◽  
The Impact

The promise of large-scale use of renewables such as wind and solar for supplying electrical power is tempered by the sources’ transient behavior and the impact this would have on the operation of the grid. One way of addressing this is through the use of supplemental energy storage. While the technology for the latter has not been proven on a large scale or to be economical at the present time, some assessments of what magnitude is required can be made. In performing this work we have used NREL’s Solar Advisor Model (SAM 2010) with TMY3 solar data to estimate the photovoltaic system power generation. Climatic conditions close to load centers were chosen for the simulations. Then the PV output for varying sizes of arrays were examined and the impact of varying amounts of storage investigated. The storage was characterized by maximum limiting energy and power capacities based on annual hourly peak load, as well as its charging and discharging efficiencies. The simulations were performed using hourly time steps with energy withdrawn from, or input to, storage only after considering base generation and the PV system output in serving the grid load. In this work, we examined the load matching capability of solar PV generation (orientated for maximum summer output) for a sample Southwestern US utility grid load of 2008. Specifically we evaluated the daily and seasonal peak load shifting with employing varying storage capacities. The annual average energy penetration based on the usable solar PV output is also examined under these conditions and at different levels of system flexibility.

scholarly journals Is There a Relationship between Surface Wettability of Structured Surfaces and Lyophobicity toward Liquid Metals?

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2283 ◽  
Author(s):  
Stephan Handschuh-Wang ◽  
Lifei Zhu ◽  
Tao Wang
Keyword(s):  
Liquid Metal ◽  
Flexible Electronics ◽  
Liquid Metals ◽  
Metal Layer ◽  
Surface Wettability ◽  
Diamond Coating ◽  
Air Plasma ◽  
Structured Surfaces ◽  
Static Contact ◽  
The Impact

The liquid metal lyophobicity of a rough substrate was, in previous articles, found to be rather independent on the surface wettability. In this article, we scrutinize the impact of surface wettability of a structured (rough) surface on the liquid metal wettability and adhesion. As a model system, a structured diamond coating was synthesized and modified by air plasma. We show that surface wettability (surface free energy) does not play a prominent role for static contact angle measurements and for the liquid metal repelling properties of the diamond coating in droplet impact experiments. In contrast, roll off angles and repeated deposition experiments illustrate that the increased hydrophilicity impacts the long-term liquid metal repellency of our coating. Liquid metal adhered after around 50 deposition/removal cycles on the hydrophilic diamond coating, while no liquid metal adhesion was visible after 100 cycles on the hydrophobic diamond coating, illustrating the fundamental role for the adhesion of liquid metal. The effect of repeated deposition in conjunction with gentle applied force was employed for coating the liquid metal lyophobic (hydrophilic) diamond coating with a thin liquid metal layer. The observed effect may find application in flexible electronics and thermal management systems as a means to improve interfacing of the liquid metal with conductive non-metal coatings.

scholarly journals Energy Evolution Law of Ore-Bearing Rock during Unloading under High Static Stress and Frequent Disturbance

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chun Wang ◽  
Mei-zhi Xie ◽  
Zu-qiang Xiong ◽  
Cheng Wang ◽  
Lu-ping Cheng
Keyword(s):  
Incident Energy ◽  
Unit Volume ◽  
Average Energy ◽  
Energy Evolution ◽  
Axial Pressure ◽  
Evolution Law ◽  
Plastic Energy ◽  
Unloading Rate ◽  
Transmitted Energy ◽  
The Impact

Based on the complex engineering environment in deep rock engineering, preloaded high axial pressure, unloading of axial pressure, and impact loading were used to simulate high in situ stress, unloading of excavation, and blasting disturbance, respectively; the experimental study on frequent impact disturbances under unloading of high static load was carried out, which aimed at revealing the energy evolution law of rock. First, the equations of elastic property, plastic energy, and incident energy in the impact process are discussed by theoretical analysis. Then, it is found by further investigation that dynamic stress-strain curve and envelope curve of rock are with the same change tendency. The initial stage was short straight stage, and then linear stage appeared and was less influenced by unloading rate. The plastic energy, the ratio of reflected energy to incident energy, and the energy consumption per unit volume of rock increase during impact. The higher the preloaded axial pressure is, the greater the ratio of reflected energy to incident energy is, the smaller the ratio of transmitted energy to incident energy and the average energy dissipation per unit volume of rock are. When the unloading rate increased, the elastic energy generated by impact gradually increased, the plasticity gradually weakened, the ratio of transmitted energy to incident energy increased, and the ratio of reflection energy to incident energy decreased.

scholarly journals The total ionisation due to the absorption in air of slow cathode rays

1927 ◽  
Vol 115 (772) ◽  
pp. 609-624 ◽  
Keyword(s):  
Kinetic Energy ◽  
Minimum Energy ◽  
Average Energy ◽  
Initial Energy ◽  
Electronic Energy ◽  
Initial Kinetic Energy ◽  
Ionisation Potential ◽  
Normal Atom ◽  
The Impact ◽  
Average Expenditure

The object of the experiments here described is to measure the average ionisation produced by the absorption in air of an electron with definite initial energy. From this the average expenditure of energy associated with the formation of a pair of ions can be estimated. The initial energies considered ranged between 200 and 1000 electron-volts. Experiments on ionisation by electronic impact have generally been concerned, either with a determination of the ionisation potential of the gas, or with the ionisation per unit path due to an electron having a definite energy. The ionisation potential has been measured by determining the minimum energy a stream of electrons must have in order to ionise, even occasionally, a normal atom. It represents the energy expended by the ionising electron if no kinetic energy be transferred to either of the ions formed. If at the impact an atomic electron were ejected with appreciable kinetic energy, the energy expended by the ionising electron would be correspondingly increased above the ionisation potential. Also electrons may dissipate their energy by processes other than ionisation, notably by excitation and by dissociation of diatomic molecules. For these reasons the average expenditure of electronic energy per pair of ions should exceed the ionisation potential. The excess of this average energy would indicate the extent to which processes other than ionisation contribute to the dissipation of the initial kinetic energy of the electrons. The purpose of the present experiments is to obtain further information on this phase of the ionisation problem.

scholarly journals Progress in laser acceleration of particles

2012 ◽  
Vol 78 (4) ◽  
pp. 321-322
Author(s):  
Chan Joshi ◽  
Wei Lu ◽  
Zhengming Sheng
Keyword(s):  
Laser Pulses ◽  
Intense Laser ◽  
Current Status ◽  
Acceleration Of Particles ◽  
Laser Wakefield Acceleration ◽  
Intense Laser Pulses ◽  
Electrons And Ions ◽  
Original Works ◽  
Laser Acceleration ◽  
Plasma Wakefield Accelerator

Laser acceleration of particles is currently a very active area of research in Plasma Physics, with an emphasis on acceleration of electrons and ions using short but intense laser pulses. In this special issue we access the current status of this field by inviting leading researchers all over the world to contribute their original works here. Many of these results were first presented at the recent Laser-Particle Acceleration Workshop (LPAW 2011) held in Wuzhen, China in June 2011. In addition to the laser wakefield acceleration (LWFA) of electrons (Tzoufras et al.) and laser acceleration of ions (Tsung et al.), there were exciting new proposals for a proton-driven plasma wakefield accelerator (Xia et al.) and for a dielectric-structure-based two-beam accelerator (Gai et al.) presented at this workshop, and we are very pleased to have the authors' contributions on these included here.

A Computational Study of Thin Film Dynamics on Micro-Structured Surfaces

2016 ◽  
Author(s):  
Linyu Lin ◽  
Nam T. Dinh ◽  
Ram Sampath ◽  
Nadir Akinci
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Surface Tension ◽  
Contact Line ◽  
Boiling Heat Transfer ◽  
Smooth Surface ◽  
High Heat ◽  
Structured Surfaces ◽  
Structured Surface ◽  
Dry Patch

The present study is motivated by interest in understanding of physical mechanisms that govern the effect of material and micro-structural characteristics of heat surface on boiling heat transfer and burnout at high heat fluxes. The effect was reported and investigated experimentally and analytically over several past decades. Only recently, with the advent of nanotechnology including microscale manufacturing, it becomes possible to perform high heat-flux boiling experiments with control of surface conditions. Of particular importance for practice is the potential for significant enhancement of boiling heat transfer (BHT) and critical heat flux (CHF) in pool and flow boiling on heaters with specially manufactured and controlled micro-structured surfaces. This enhancement is very important to a very wide range of engineering applications, like heat exchanger and cooling system, where maximum flux is needed. Currently, there are many controlled experiments that investigate such effect and they lend themselves a subject for detailed computational analysis. The focus of this study is micro-hydrodynamics of the evaporating thin liquid film at the receding triple contact line, corresponding to formation of dry spot in the footprint of a growing bubble. Parametric investigations are performed to assess the hypotheses that micro-structured surfaces enhance resilience to burnout due to residual liquid in the dry patch after contact line receding. Towards the study objective, a particle-based (mesh-less) method of computational fluid dynamics called Smoothed Particle Hydrodynamics (SPH) is adopted. The SPH method is selected for its capability to handle fluid dynamics in complex geometries and free surface problems without mass loss (characteristic of alternative interface capturing schemes used in mesh-based methods). Both surface tension and surface adhesion (hydrophilicity) are implemented and tested. The solid (heater) surface and manufactured micro-structures are represented by solid-type particles. Heat transfer, phase change (evaporation) and vapor dynamics are not included in the present simulation. The bouncing drop case measures the contact time of water droplet with solid surface. This case is used for “mesh” sensitivity (particle size) study and calibration of boundary conditions and surface tension coefficient. Subsequently, case studies are formulated and performed for contact line dynamics on heater surfaces with the fabricated Micro Pillar Arrays surfaces (MPA) and smooth surface. Variable characteristics include surface tension and pillar density on structured surface (modified by changing distance between pillars). First of all, residual fluid are found in all simulations with structured surface, while fluid are drained for smooth cases. For structured surface, it’s found that after the contact line recedes, fluid with higher surface tension resides in the dry patch more than fluid with lower coefficient, and the relation tends to be non-linear. While for smooth surface, all fluid will be drained after certain time and the relations are non-monotonic; it’s also found that the amount of residual fluid increase as the distance between pillars decreases until a limit. The fluid then starts to decrease with pillars being set further apart. The increase starts from 30 μm and the limit is around 10 μm.

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