Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

1970 ◽  
Vol 28 ◽  
pp. 360-361
Author(s):  
John W. Coleman
Keyword(s):  
Boundary Conditions ◽  
High Performance ◽  
Force Fields ◽  
Optical Design ◽  
Direct Conversion ◽  
Design Engineering ◽  
Design Data ◽  
Scalar Potentials ◽  
Geometric Elements ◽  
At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

Molecular Dynamics Using Non-Variational Polarizable Force Fields: Theory, Periodic Boundary Conditions Implementation and Application to the Bond Capacity Model

2019 ◽  
Author(s):  
Pier Paolo Poier ◽  
Louis Lagardere ◽  
Jean-Philip Piquemal ◽  
Frank Jensen
Keyword(s):  
Boundary Conditions ◽  
Periodic Boundary ◽  
Force Fields ◽  
Periodic Boundary Conditions ◽  
Computational Effort ◽  
Polarizable Force Fields ◽  
Energy Models ◽  
Capacity Model ◽  
Energy Gradient ◽  
Polarization Models

<div> <div> <div> <p>We extend the framework for polarizable force fields to include the case where the electrostatic multipoles are not determined by a variational minimization of the electrostatic energy. Such models formally require that the polarization response is calculated for all possible geometrical perturbations in order to obtain the energy gradient required for performing molecular dynamics simulations. </p><div> <div> <div> <p>By making use of a Lagrange formalism, however, this computational demanding task can be re- placed by solving a single equation similar to that for determining the electrostatic variables themselves. Using the recently proposed bond capacity model that describes molecular polarization at the charge-only level, we show that the energy gradient for non-variational energy models with periodic boundary conditions can be calculated with a computational effort similar to that for variational polarization models. The possibility of separating the equation for calculating the electrostatic variables from the energy expression depending on these variables without a large computational penalty provides flexibility in the design of new force fields. </p><div><div><div> </div> </div> </div> <p> </p><div> <div> <div> <p>variables themselves. Using the recently proposed bond capacity model that describes molecular polarization at the charge-only level, we show that the energy gradient for non-variational energy models with periodic boundary conditions can be calculated with a computational effort similar to that for variational polarization models. The possibility of separating the equation for calculating the electrostatic variables from the energy expression depending on these variables without a large computational penalty provides flexibility in the design of new force fields. </p> </div> </div> </div> </div> </div> </div> </div> </div> </div>

scholarly journals High-Performance Ultra-Thin Spectrometer Optical Design Based on Coddington’s Equations

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 323
Author(s):  
Zhiwei Feng ◽  
Guo Xia ◽  
Rongsheng Lu ◽  
Xiaobo Cai ◽  
Hao Cui ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
High Performance ◽  
Optical Design ◽  
Pixel Size ◽  
Simulation Design ◽  
Central Wavelength ◽  
Spot Radius ◽  
Unique Method ◽  
Almost All

A unique method to design a high-throughput and high-resolution ultrathin Czerny–Turner (UTCT) spectrometer is proposed. This paper reveals an infrequent design process of spectrometers based on Coddington’s equations, which will lead us to develop a high-performance spectrometer from scratch. The spectrometer is composed of cylindrical elements except a planar grating. In the simulation design, spot radius is sub-pixel size, which means that almost all of the energy is collected by the detector. The spectral resolution is 0.4 nm at central wavelength and 0.75 nm at edge wavelength when the width of slit is chosen to be 25 μm and the groove density is 900 lines/mm.

scholarly journals ACHIEVING EFFECTIVE SERVICE DELIVERY BY LOCAL GOVERNMENT EMPLOYEES THROUGH STRATEGIC TRAINING PROGRAMMES

2020 ◽  
Vol 2 (1) ◽  
pp. 131-141
Author(s):  
Love Arugu ◽  
Keyword(s):  
Local Government ◽  
Service Delivery ◽  
High Performance ◽  
Government Employees ◽  
Continuous Training ◽  
Design Data ◽  
Analytical Technique ◽  
Ex Post ◽  
Strategic Training ◽  
Effective Service

The thesis of the study is that effective service delivery by the local government employees is a function of a strategic training framework. Extant literature examined captured the importance of training and development programmes in the local government and stated among other things, that training increases employees productivity, reduce costs, boost morale, promote stability, flexibility and service delivery at the grassroots. The arguments are substantiated with the training and high-performance theory advanced by Gallie and White (1993). The study adopts ex post facto design. Data are obtained from secondary sources and analysed using the content analytical technique. Empirical analysis of literature provides the framework for conclusion and policy recommendation. The study advocates for a strategic continuous training plan to enhance the capacity of local government employees and service delivery in Nigeria.

scholarly journals Monte Carlo Simulations of Coupled Transient Seepage Flow and Soil Deformation in Levees

2020 ◽  
Vol 21 (1) ◽  
pp. 147-156
Author(s):  
Fred Thomas Tracy ◽  
Jodi L. Ryder ◽  
Martin T. Schultz ◽  
Ghada S. Ellithy ◽  
Benjamin R. Breland ◽  
...  
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Boundary Conditions ◽  
High Performance ◽  
Hurricane Ike ◽  
Finite Element Program ◽  
Conservation Of Mass ◽  
Total Head ◽  
Element Program ◽  
Finite Element Node

The purpose of this research is to compare the results from two different computer programs of flow analysesof two levees at Port Arthur, Texas where rising water of a flood from Hurricane Ike occurred on the levees. The first program (Program 1) is a two-dimensional (2-D) transient finite element program that couples the conservation of mass flow equation with accompanying hydraulic boundary conditions with the conservation of force equations with accompanying x and y displacement and force boundary conditions, thus yielding total head, x displacement, and y displacement as unknowns at each finite element node. The second program (Program 2) is a 2-D transient finite element program that considers only the conservation of mass flowequation with its accompanying hydraulic boundary conditions, yielding only total head as the unknown at each finite element node. Compressive stresses can be computed at the centroid of each finite element when using the coupled program. Programs 1 and 2 were parallelized for high performance computing to consider thousands of realisations of the material properties. Since a single realisation requires as much as one hour of computer time for certain levees, the large realisation computation is made possible by utilising HPC. This Monte Carlo type analysis was used to compute the probability of unsatisfactory performance for under seepage, through seepage, and uplift for the two levees. Respective hydrographs from the flood resulting from Hurricane Ike were applied to each levee. When comparing the computations from the two programs, the most significant result was the two programs yielded significantly different values in the computed results in the two clay levees considered in this research.  

Optical design of high performance con-focal microscopy with digital micro-mirror and stray light filters

Optik ◽  
2010 ◽  
Vol 121 (22) ◽  
pp. 2073-2079 ◽  
Author(s):  
Chuan-Cheng Hung ◽  
Yi-Chin Fang ◽  
Cheng-Mu Tsai ◽  
Chang-Ching Lin ◽  
Koung-Ming Yeh ◽  
...  
Keyword(s):  
High Performance ◽  
Optical Design ◽  
Stray Light ◽  
Light Filters

scholarly journals Biomass to porous carbon in one step: directly activated biomass for high performance CO2 storage

2017 ◽  
Vol 5 (24) ◽  
pp. 12330-12339 ◽  
Author(s):  
Norah Balahmar ◽  
Abdul Salam Al-Jumialy ◽  
Robert Mokaya
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Lower Cost ◽  
Activated Carbons ◽  
Co2 Storage ◽  
Direct Conversion ◽  
Step Process ◽  
One Step ◽  
Hydrothermal Carbonisation ◽  
Activated Biomass

The direct conversion of biomass to activated carbons in a simple and lower cost one step process, which negates the need for hydrothermal carbonisation or pyrolysis, generates activated carbons with properties and CO2 uptake comparable or superior to those of conventionally prepared activated carbons.

Generation of Design Data Through Numerical Modeling of a Post and Dome Feature

1999 ◽  
Author(s):  
David A. Nichols ◽  
Anthony F. Luscher
Keyword(s):  
High Performance ◽  
Shear Loading ◽  
Design Parameters ◽  
Insertion Force ◽  
Design Data ◽  
Beam Equations ◽  
Regression Techniques ◽  
Sensitivity Data ◽  
Improved Design ◽  
Main Effects

Abstract This paper focuses on developing improved design equations to estimate the retention strength, insertion force, and insertion strain of a particular snap-fit, the post and dome feature. Finite element methods and multiple regression techniques were used in lieu of beam equations to develop the improved design equations. Sensitivity data is plotted for both the main effects and selected variable interactions. A study of detailed catch geometry was done in order to identify an optimal catch geometry. Typical design parameters were varied in order to develop design equations for users of this feature. The post and dome feature was selected for analysis because it is a high performance snap-fit that is self-datuming and can take some shear loading in addition to retention. The post and dome provide a higher ratio of retention force to insertion force than traditional cantilever snap-fits, and retention is less dependent on friction.

Systematic Optical Design of Constituting Layers to Realize High-Performance Red-Selective Thin-Film Organic Photodiodes

2018 ◽  
Vol 6 (4) ◽  
pp. 1701085 ◽  
Author(s):  
Seongwon Yoon ◽  
Chang Woo Koh ◽  
Han Young Woo ◽  
Dae Sung Chung
Keyword(s):  
Thin Film ◽  
High Performance ◽  
Optical Design

scholarly journals ON CONTROLLING A CHAOTIC SYSTEM

1991 ◽  
Vol 05 (22) ◽  
pp. 1489-1497 ◽  
Author(s):  
HAIM H. BAU
Keyword(s):  
Dynamical Systems ◽  
Feedback Control ◽  
Boundary Conditions ◽  
Chaotic Attractor ◽  
Bifurcation Structure ◽  
Small Perturbations ◽  
Chaotic Flow ◽  
Active Feedback ◽  
Active Feedback Control ◽  
At Will

The use of active (feedback) control to alter the bifurcation structure of dynamical systems is discussed and illustrated with an example. It is shown that with the use of a feedback controller effecting small perturbations in the boundary conditions, one can stabilize some of the otherwise non-stable orbits embedded in the chaotic attractor. The controller also can be used to destabilize stable flows or, in other words, to induce chaos in otherwise laminar (fully predictable), non-chaotic flow. Finally, the controller can be used to switch at will from one flow pattern to another.

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