Effects of Vertical Direction and Aperture Size on the Perception of Visual Acceleration

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

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Fore-Aft Forces in Tire-Wheel Assemblies Generated by Unbalances and the Influence of Balancing

Tire Science and Technology ◽

10.2346/1.2141713 ◽

1991 ◽

Vol 19 (3) ◽

pp. 142-162 ◽

Cited By ~ 4

Author(s):

D. S. Stutts ◽

W. Soedel ◽

S. K. Jha

Keyword(s):

Mathematical Model ◽

Elastic Foundation ◽

Torsional Oscillation ◽

Vertical Direction ◽

Torsional Stiffness ◽

Rolling Motion ◽

Vertical Force ◽

Horizontal Force ◽

Wheel Rim ◽

Open Question

Abstract When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argues in favor of torsional oscillations caused by a changing rolling radius. But it appears that there is a simpler answer. In this paper, a mathematical model of a tire consisting of a rigid tread ring connected to a freely rotating wheel or hub through an elastic foundation which has radial and torsional stiffness was developed. This model shows that an unbalanced mass on the tread ring will cause an oscillatory rolling motion of the tread ring on the drum which is superimposed on the nominal rolling. This will indeed result in larger fore-aft than vertical force variations beyond certain speeds, which are a function of run-out. The rolling motion is in a certain sense a torsional oscillation, but postulation of a changing rolling radius is not necessary for its creation. The model also shows the limitation on balancing the tire-wheel assembly at the wheel rim if the unbalance occurs at the tread band.

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About the Development of Brick-Design in Russia

Stroitel nye Materialy ◽

10.31659/0585-430x-2020-787-12-21-24 ◽

2020 ◽

Vol 787 (12) ◽

pp. 21-24

Author(s):

Y.A. Bozhko ◽

◽

K.A. Lapunova ◽

Keyword(s):

Functional Role ◽

Three Dimensional ◽

Vertical Direction ◽

Basic Unit ◽

Design Development ◽

European Cities ◽

Unique Material ◽

Decisive Action ◽

Color Combinations ◽

Insufficient Number

The article reflects the authors view on the technical and aesthetic side of the use of face bricks in the architecture of our country. The term brick design combines such indicators of brickwork as the color, size and surface of the brick itself, as well as the type of masonry and seam parameters. Unfortunately, the analysis of the current situation shows that the culture of consumption of face bricks in Russia remains at a low level, which is due to the lack of proper knowledge and insufficient number of qualified master masons. The main goal of brick design development is to popularize various types of three-dimensional masonry and reveal the potential of using bricks as a basic unit. The comparison shows the architecture of European cities, which does not differ in the complexity of architectural forms, but has advantages in the form of unusual masonry, color combinations, vertical direction of masonry and other elements of technical aesthetics. The use of bricks in various levels of brick design will allow you to avoid using architectural decoration on the facades of buildings, while preserving its authenticity and individuality. The brick, as a basic unit, is self-sufficient and is able to fulfill not only its functional role, but also its aesthetic one. In this situation, a necessary and decisive action will be competent communication with industry specialists, architects and designers, leading manufacturers and technologists who realize that we have a unique material that does not need additional wrapping when used efficiently.

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Guide to the choice of aperture size and wire diameter combinations for industrial wire screens and woven wire cloth

10.3403/00234437u ◽

2015 ◽

Keyword(s):

Wire Diameter ◽

Aperture Size ◽

Wire Cloth

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Outcome and Safety of Different Cumulative Doses and Protocols of Intravenous Methylprednisolone in Moderate to Severe and Active Graves’ Ophthalmopathy

Ophthalmologica Indonesiana ◽

10.35749/journal.v43i1.131 ◽

2019 ◽

Vol 43 (1) ◽

pp. 15

Author(s):

Amelya Permata Sari ◽

M Sidik ◽

Syntia Nusanti

Keyword(s):

Clinical Outcome ◽

Literature Search ◽

Oral Route ◽

Eye Disease ◽

Aperture Size ◽

Journal Articles ◽

Inclusion Criteria ◽

Intravenous Methylprednisolone ◽

Graves Ophthalmopathy ◽

Graves Orbitopathy

Background: Graves’ ophthalmopathy (GO), also known as Graves’ orbitopathy or thyroid eye disease, has a potential sight-threatening complications. The activity and severity are important determinants in GO and are implications for treatment. Intravenous Glucocorticoid (GC) was associated with significantly greater efficacy and was better tolerated than oral route in the treatment of patients with moderate to severe and active GO. Intravenous GC has a variation cumulative dose and protocols; meanwhile the optimal treatment is still undefined. The aim of this literature review was to analyze the outcome and safety of different cumulative doses and protocols of intravenous methylprednisolone of patients with moderate to severe and active GO. Methods: The literature search was conducted from Google Scholar and Pubmed for journal articles that were published and related to the use of IVGC in moderate to severe and active GO Results: From the keywords mentioned, titles were screened for eligibility and seventeen articles were found. After being checked for the duplication, the articles were screened based on the abstracts and/or full texts. As many as eight articles met the inclusion criteria, others were excluded. Conclusion: Intravenous GC therapy in moderate to severe and active GO provide effect in reducing CAS, decreasing lid aperture size, decreasing proptosis size, and disappearing diplopia. A protocol uses a low cumulative doses (<5 g) of methylprednisolone weekly for 6 weeks and then halved dose weekly for another 6 weeks are preferred due to higher response in clinical outcome and safety profile.

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Theoretical analysis and experimental research on multi-layer elastic damping track structure

Advances in Mechanical Engineering ◽

10.1177/1687814021994975 ◽

2021 ◽

Vol 13 (2) ◽

pp. 168781402199497

Author(s):

Guanghui Xu ◽

Shengkai Su ◽

Anbin Wang ◽

Ruolin Hu

Keyword(s):

Finite Element ◽

Analytical Solution ◽

Finite Element Simulation ◽

Reaction Force ◽

Vibration Reduction ◽

Vertical Direction ◽

Propagation Path ◽

Track Structure ◽

Test Results ◽

Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

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Research on springback characteristic in flexible multi-points 3D stretch-bending process

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211028476 ◽

2021 ◽

pp. 095440542110284

Author(s):

Song Gao ◽

Tonggui He ◽

Qihan Li ◽

Yingli Sun ◽

Jicai Liang

Keyword(s):

Simulation Model ◽

High Efficiency ◽

Vertical Direction ◽

Factors Affecting ◽

Stretch Bending ◽

Element Simulation ◽

Bending Process ◽

Bending Radius ◽

Aluminum Profiles ◽

Bending Sequence

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.

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Comparison of one versus two maxillary molars distalization with iPanda: a finite element analysis

Progress in Orthodontics ◽

10.1186/s40510-021-00356-6 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Kamontip Sujaritwanid ◽

Boonsiva Suzuki ◽

Eduardo Yugo Suzuki

Keyword(s):

Finite Element ◽

Stress Distribution ◽

Alveolar Bone ◽

Vertical Direction ◽

Minimal Amount ◽

Element Analysis ◽

Molar Distalization ◽

Second Molar ◽

Maxillary Molars ◽

Displacement Patterns

Abstract Background The purpose of this study was to compare the stress distribution and displacement patterns of the one versus two maxillary molars distalization with iPanda and to evaluate the biomechanical effect of distalization on the iPanda using the finite element method. Methods The finite element models of a maxillary arch with complete dentition, periodontal ligament, palatal and alveolar bone, and an iPanda connected to a pair of midpalatal miniscrews were created. Two models were created to simulate maxillary molar distalization. In the first model, the iPanda was connected to the second molar to simulate a single molar distalization. In the second model, the iPanda was connected to the first molar to simulate “en-masse” first and second molar distalization. A varying force from 50 to 200 g was applied. The stress distribution and displacement patterns were analyzed. Results For one molar, the stress was concentrated at the furcation and along the distal surface in all roots with a large amount of distalization and distobuccal crown tipping. For two molars, the stress in the first molar was 10 times higher than in the second molar with a great tendency for buccal tipping and a minimal amount of distalization. Moreover, the stress concentration on the distal miniscrew was six times higher than in the mesial miniscrew with an extrusive and intrusive vector, respectively. Conclusions Individual molar distalization provides the most effective stress distribution and displacement patterns with reduced force levels. In contrast, the en-masse distalization of two molars results in increased force levels with undesirable effects in the transverse and vertical direction.

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Free Stream Behavior of Hydrogen Released from a Fluidic Oscillating Nozzle

Fluids ◽

10.3390/fluids6070245 ◽

2021 ◽

Vol 6 (7) ◽

pp. 245

Author(s):

Anja Fink ◽

Oliver Nett ◽

Simon Schmidt ◽

Oliver Krüger ◽

Thomas Ebert ◽

...

Keyword(s):

Free Stream ◽

Combustion Engine ◽

Direct Injection ◽

Combustion Process ◽

Vertical Direction ◽

Spray Angle ◽

Transport Sector ◽

Flow Measurements ◽

Injection Process ◽

Bottom Dead Center

The H2 internal combustion engine (ICE) is a key technology for complete decarbonization of the transport sector. To match or exceed the power density of conventional combustion engines, H2 direct injection (DI) is essential. Therefore, new injector concepts that meet the requirements of a H2 operation have to be developed. The macroscopic free stream behavior of H2 released from an innovative fluidic oscillating nozzle is investigated and compared with that of a conventional multi-hole nozzle. This work consists of H2 flow measurements and injection tests in a constant volume chamber using the Schlieren method and is accompanied by a LES simulation. The results show that an oscillating H2 free stream has a higher penetration velocity than the individual jets of a multi-hole nozzle. This behavior can be used to inject H2 far into the combustion chamber in the vertical direction while the piston is still near bottom dead center. As soon as the oscillation of the H2 free stream starts, the spray angle increases and therefore H2 is also distributed in the horizontal direction. In this phase of the injection process, spray angles comparable to those of a multi-hole nozzle are achieved. This behavior has a positive effect on H2 homogenization, which is desirable for the combustion process.

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Analysis of Non-Stationarity for 5.9 GHz Channel in Multiple Vehicle-to-Vehicle Scenarios

Sensors ◽

10.3390/s21113626 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3626

Author(s):

Fang Li ◽

Wei Chen ◽

Yishui Shui

Keyword(s):

Transmission Rate ◽

Radio Channel ◽

Vertical Direction ◽

Statistical Characteristics ◽

Small Scale ◽

Delay Spread ◽

Important Indicator ◽

Power Delay Profile ◽

Channel Characteristics ◽

Vehicle To Vehicle

The vehicle-to-vehicle (V2V) radio channel is non-stationary due to the rapid movement of vehicles. However, the stationarity of the V2V channels is an important indicator of the V2V channel characteristics. Therefore, we analyzed the non-stationarity of V2V radio channels using the local region of stationarity (LRS). We selected seven scenarios, including three directions of travel, i.e., in the same, vertical, and opposite directions, and different speeds and environments in a similar driving direction. The power delay profile (PDP) and LRS were estimated from the measured channel impulse responses. The results show that the most important influences on the stationary times are the direction and the speed of the vehicles. The average stationary times for driving in the same direction range from 0.3207 to 1.9419 s, the average stationary times for driving in the vertical direction are 0.0359–0.1348 s, and those for driving in the opposite direction are 0.0041–0.0103 s. These results are meaningful for the analysis of the statistical characteristics of the V2V channel, such as the delay spread and Doppler spread. Small-scale fading based on the stationary times affects the quality of signals transmitted in the V2V channel, including the information transmission rate and the information error code rate.

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