scholarly journals Investigations on Stresses in Optical Components with Spherical Surfaces

2019 ◽  
Vol 18 (5) ◽  
pp. 416-421
Author(s):  
A. S. Kozeruk ◽  
Y. L. Malpica ◽  
M. I. Filonova ◽  
V. O. Kuznechik
Keyword(s):  
Electronic Device ◽  
Side Surface ◽  
Front Surface ◽  
Contact Method ◽  
Optical Components ◽  
Force Magnitude ◽  
Spherical Surfaces ◽  
Optimum Position ◽  
Grinding Conditions ◽  
Mechanical Attachment

The paper has substantiated an expediency to fix lenses with a thin center (biconcave, flat concave and negative meniscus) to a non-operational cylindrical surface. This avoids their temperature distortion at the blocking stage which is a reason for occurrence of irremovable micro and macro errors on executive surfaces of a component after its unblocking and it causes astigmatism in an image which is formed by an optical-electronic device. The paper considers a method for attachment of a lens to its side surface and it contains a design description of the device for mechanical attachment of the studied lenses during their simultaneous double-sided abrasive processing under free-grinding conditions. The paper presents a methodology for determination of a stressed state in lenses, which is based on a mathematical model of a uniform elastic isotropic deformation of a solid body. This approach takes into account a finite element method which consists in an approximation of a body under study with the help of a model presenting a set of elements with a finite number of freedom degrees which are interrelated at node points. The investigations have been executed with the purpose to study a nature of deformation distribution in a lens which made it possible to establish a directly proportional dependence of displacements in the center of the part on the magnitude of clamping forces. The paper reveals an insignificant influence of a clamping force magnitude and elastic characteristics of a lens on an optimum position of an application plane of its clamping forces. A non-contact method for monitoring errors on a polished lens surface using an interferometer with a reference front surface has been proposed in the paper.

scholarly journals TRANSFORMATION AND SCATTERING OF SURFACE WAVES ON THE ACOUSTIC LOAD TO ULTRASONIC EVALUATION AND MEASUREMENTS. Part 2. The object to study – solid with ledge

2018 ◽  
Vol 9 (2) ◽  
pp. 142-154 ◽  
Author(s):  
A. R. Baev ◽  
A. L. Mayorov ◽  
M. V. Asadchaya ◽  
G. E. Konovalov ◽  
O. S. Sergeeva
Keyword(s):  
Surface Waves ◽  
Side Surface ◽  
Front Surface ◽  
Technical Application ◽  
Small Aperture ◽  
Transverse Waves ◽  
Longitudinal Modes ◽  
Ultrasonic Evaluation ◽  
Lack Of Information ◽  
Transition Radius

The lack of information about the features of processes of the surface wave's transformation into volume waves and its scattering in metal objects with ledge, slots, grooves and the others is one of the obstacles to improve of the acoustical testing reliability and widening of technical application. The aim of this work was to study of mechanism of acoustical mode's transformation and determination the laws of the fields forming of scatted volume edge wave's in solids with ledge of different geometry and to suggest direction of the study application in area of acoustical testing and measurements.The features of transformation of surface waves into edge transverse and longitudinal wave modes scatted and their fields forming in the volume of the object with ledge vs. its angle of the slope front surface side (0–135°) and a dimensionless transition radius (0–10,2) varied were studied. Theoretical analysis and experimental data shown that in general case the field of the edge transverse waves in the volume of ledge can be imagined as a superposition of the field of edge waves (scatted on ledge) and accompany waves too, radiated simultaneously with the surface waves to radiate. If dimensionless size of the ledge's transition radius lesser than 1 the resulting field of the edge transverse waves is the summary field of two sources. One of them (with small aperture) is localized in the vicinity of the place of intersection of contact surface with ledge's front side surface. As it was found, the second source of the edge transverse waves – the edge head longitudinal waves to appear in the results of transformation of surface waves on the ledge′s radius transition. The structure of the edge acoustic fields including their extremes vs. ledge's angle and its radius transition, position of the surface wave's probe were experimentally studied and theoretically analyzed.Some directions of the results of researches using are the next: а) ultrasonic testing of hard-to-make technological objects in which defects have low sound reflection; b) ultrasonic structure diagnostics of solid (specimens) set far from the ultrasonic by using edge volume transverse and longitudinal modes; c) creation of new ultrasonic arrangements to sound and to receive transverse waves of different polarization.

Characterization of Forces in High-Speed Bone Cutting and Grinding for Haptics Rendering

2016 ◽  
Author(s):  
Avinash Danda ◽  
Yi Tang Kao ◽  
Mathew A. Kuttolamadom ◽  
Bruce L. Tai
Keyword(s):  
Feed Rate ◽  
High Speed ◽  
Force Feedback ◽  
Identical Condition ◽  
Tool Orientation ◽  
Force Magnitude ◽  
Force Profile ◽  
Grinding Conditions ◽  
Surgical Simulations

This study characterizes the forces in high-speed bone cutting and grinding for the use of haptic devices in surgical simulations. Unrealistic force feedback due to the lack of vibrational features is one of the most common drawbacks. Generally, the force profile can be decomposed to a mean force and a vibrational force magnitude. These forces are experimentally measured under various motions, including feed rate and tool orientation, to mimic manual operations and to understand the effects of these parameters. Change in feed rate was found to be insignificant in the overall force feedback, while the change in tool orientation showed statistically significant effects. The grinding burr and cutting burr also exhibited different forces under an identical condition. The explanation for the behavior of the forces based on the cutting and grinding conditions is discussed along with the results.

scholarly journals ANALYSIS OF THE CYCLICAL GROUND CUTTING

2019 ◽  
Vol 16 (6) ◽  
pp. 642-657 ◽  
Author(s):  
V. A. Nikolayev
Keyword(s):  
Synthesis Method ◽  
Side Surface ◽  
Front Surface ◽  
Cutting Parameters ◽  
General Purpose ◽  
Total Force ◽  
Cost Of Energy ◽  
Final Manuscript ◽  
Working Bodies ◽  
The Cost

Introduction. Rotary rippers are needed for cyclical cutting of the ground when the underlying layer and slopes of the roads are formed. Therefore, the general purpose of the research is the theoretical justification of the design and mode of rotary ripper’s parameters. Using the synthesis method, researches get only indicative results. In order to calculate the parameters of ground cutting, it is necessary to analyze the interaction of working bodies with the ground.Materials and methods. Based on the planned ways to reduce the cost of energy for cyclical cutting of the ground, the author developed the calculation method of the working body: the force of cutting the ground with the toe of the working body; the force necessary for the primary shift of the ground by the front surface of the working body; the total force of ground displacement by an active working body; the friction of the side surfaces of the working body on the ground during the rotation.Results. The author calculated the specific values in the process of rotation by using the developed method of determining the parameters of the cyclic ground cutting and basing on the accepted data. Moreover, the author constructed and approximated the graphs’ dependencies of ground cutting parameters of the rotor angle. In particular, there were dependencies: the force required to shift the ground by an active working body, the mass of the displaced ground, the acceleration of the displaced ground, the force needed to accelerate the displaced soil, the force of the ground’s impact on the side surface of the displaced ground wedge, the friction force displaced by the active working body of the ground wedge on the array of soil, the total force of the displacement of the ground by the active working body from the angle of the rotor when moving the unit at various transmissions II range of tractor HTP-17221.Discussion and conclusions. The method of calculating the forces of the ground cutting and calculating their specific values helps to determine the required rotational moment and power of the rotor drive.The author has read and approved the final manuscript. Financial transparency: the author has no financial interest in the presented materials or methods. There is no conflict of interest.

Quasi-Optical Testbed for Wideband THz On-Wafer Measurements

2019 ◽  
Vol 2019 (DPC) ◽  
pp. 001311-001322
Author(s):  
Yiran Cui ◽  
Georgios C. Trichopoulos
Keyword(s):  
Insertion Loss ◽  
Free Space ◽  
Cutoff Frequency ◽  
Experimental Results ◽  
Ultra Wideband ◽  
Contact Method ◽  
Optical Coupler ◽  
Optical Components ◽  
Contact Probe ◽  
Measurement Capabilities

At mmW and THz band, on-wafer testing is very critical for on-wafer electronics devices and circuits as well as spectroscopy. Nevertheless, current measurement capabilities are limited by contact probe technology and vector network analyzers (VNAs). Recently, we proposed a non-contact method to tackle the issue of using expensive and brittle contact probes. Using quasi-optics and on-chip antennas, the signals from the THz VNA are coupled on the device under test (DUT) with low insertion loss and unmatched repeatability. However, the bandwidth and cutoff frequency limitations of VNAs limit the scope of THz measurements and increase the complexity. State-of-the-art VNAs use external frequency multipliers, namely VNA extenders, to up-convert the VNA signal to the THz band. The problem of using such extenders is three-fold: 1) The maximum cutoff barely breaks it into the THz band, 2) they are bandlimited, and 3) they are extremely expensive due to costs associated with waveguide micromachining and sophisticated semiconductor processes for the electronics. Here, we propose the design of a novel quasi-optical on-wafer testbed that is compatible with photonics-based sources and detectors (e.g., photomixers) and use THz optical components instead of traditional waveguide structures to route the THz signals. With photomixers we can implement cost effective THz sources or receivers that can be efficiently integrated with quasi-optics. They feature a relatively simple topology and operate in a very wide bandwidth, typically from less than 100 GHz to more than 3 THz. Since the optical components are frequency independent, by adopting photomixers as THz emitter and detectors, the proposed quasi-optical system has a potential to achieve ultra-wideband on-wafer measurement capabilities. First, we talk about the design of the quasi-optical coupler consists of two beam splitters, which is used to discriminate between the reference and the measurement signals. Through a rigorous theoretical analysis and experiments we verified a minimum 60 dB isolation and less than 3 dB of insertion loss in the 330–500 GHz band. Then, we discuss how to use this quasi-optical coupler to implement one-port free-space measurements. We also discuss the calibration process and present three calibration standards that eliminate the error terms of the one-port free-space measurement topology. The experimental results we collected from our free-space measurements are shown afterwards. The results for two different DUTs show a good agreement between the measurement and the theoretical reflection coefficients. Next, we present the on-wafer testbed, which is constructed by a quasi-optical coupler and a non-contact probe. We also briefly introduce the on-wafer calibration approach and on-wafer standards. We notice that, in order to couple the THz beam to the on-wafer DUT, all the on-wafer standards and DUTs need to be integrated with probing antennas. Finally, we show the experimental results we obtained from one-port on-wafer measurements. For two different on-wafer DUTs, the measurement results agree with the simulations very well. Besides, with multiple measurements, we also verified that the proposed quasi-optical testbed has a good repeatability.

Numerical Study on a Flow Field in the Rinsing Process of a Beverage Can Transported With a Constant Velocity

2021 ◽  
Author(s):  
Tatsuma Kawachi ◽  
Takuto Sasaki ◽  
Aya Kaneko ◽  
Yu Nishio ◽  
Takanobu Ogawa
Keyword(s):  
Flow Field ◽  
Constant Velocity ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Side Surface ◽  
Front Surface ◽  
Experimental Result ◽  
Navier Stokes ◽  
Navier Stokes Equations

Abstract The present study investigates the flow field in a rinsing process of a beverage can numerically and experimentally. The three-dimensional Navier-Stokes equations are solved with a finite volume method along with the volume of fluid (VOF) method for free surface. The beverage can set upside down is transported with a constant velocity and rinsed with a water jet ejected from a nozzle below the can. The case of a can at rest is also simulated. The result shows that the ejected water impinges on the can bottom and spreads along the side surface of the can. Then, as it flows down toward the can mouth, its front surface forms splashes. For the stationary can case, after the jet impinges on the can bottom, it almost evenly spreads over the side surface. The water flows downward and becomes branched flows by fingering. The time average of VOF is calculated to visualize the regions rinsed by water. For the case of a moving can, only the top region of the can is rinsed, and the ratio of the rinsed region drops to 29% from 69% for the stationary case. The computed water surfaces qualitatively agree with the experimental result, but the shape of the front surface, such as splashes and fingerings, cannot be resolved with the simulation.

The use of non-smooth surfaces to control the wake of a high speed train

2019 ◽  
Vol 234 (9) ◽  
pp. 1041-1053
Author(s):  
Dongwei Wang ◽  
Chunjun Chen ◽  
Chao Deng
Keyword(s):  
High Speed ◽  
Smooth Surface ◽  
Passive Control ◽  
Aerodynamic Drag ◽  
Vortex Motion ◽  
Control Process ◽  
Side Surface ◽  
Front Surface ◽  
High Speed Train ◽  
Detached Eddy Simulation

To solve some problems caused by the wake of a high-speed train, the control process, especially the mechanism of the non-smooth surface for controlling the wake of a high-speed train, is studied by using the detached eddy simulation. The numerical simulation method is validated by using the data from a wind tunnel experiment reported in literature. To study the passive control of the wake, the non-smooth surface is arranged on the front surface and the side surface of the train, respectively. The changes of the vortex structure, velocity, and aerodynamic drag before and after the control are presented, and then the flow control mechanism of the non-smooth surface is explored in detail. The results show that by arranging the non-smooth surface on the front and side surface of the tail car, the vortex motion in the tail of the train can be slowed down and the influence region of the wake can be shortened. At the same time, the velocity fluctuation amplitude in the wake region of the train apparently decreases and the aerodynamic drag of the train decreases after the control.

Design technique for all-dielectric non-polarizing beam splitter plate

2012 ◽  
Vol 20 (1) ◽  
Author(s):  
A. Rizea
Keyword(s):  
Thin Film ◽  
Beam Splitter ◽  
Electronic Device ◽  
Polarization State ◽  
Dielectric Materials ◽  
Splitter Plate ◽  
Design Technique ◽  
Optical Components ◽  
20 Nm ◽  
Polarizing Beam Splitter

AbstractThere are many situations when, for the proper working, an opto-electronic device requiring optical components does not change the polarization state of light after a reflection, splitting or filtering. In this paper, a design for a non-polarizing beam splitter plate is proposed. Based on certain optical properties of homogeneous dielectric materials we will establish a reliable thin film package formula, excellent for the start of optimization to obtain a 20-nm bandwidth non-polarizing beam splitter.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

Electronic Cone Illumination with the Conventional Transmission Electron Microscope

1977 ◽  
Vol 35 ◽  
pp. 72-73
Author(s):  
William Krakow
Keyword(s):  
Electronic Device ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Hollow Cone ◽  
Transmission Electron ◽  
Lissajous Figures ◽  
High Resolution Images ◽  
Imaging Mode ◽  
Diffraction Patterns ◽  
Transmission Microscope

An electronic device has been constructed which manipulates the primary beam in the conventional transmission microscope to illuminate a specimen under a variety of virtual condenser aperture conditions. The device uses the existing tilt coils of the microscope, and modulates the D.C. signals to both x and y tilt directions simultaneously with various waveforms to produce Lissajous figures in the back-focal plane of the objective lens. Electron diffraction patterns can be recorded which reflect the manner in which the direct beam is tilted during exposure of a micrograph. The device has been utilized mainly for the hollow cone imaging mode where the device provides a microscope transfer function without zeros in all spatial directions and has produced high resolution images which are also free from the effect of chromatic aberration. A standard second condenser aperture is employed and the width of the cone annulus is readily controlled by defocusing the second condenser lens.

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