Stress-strain numerical simulation for a microprofile subjected to orthogonal impact under constrained loading conditions

The present paper aims to describe shape changes in a microroughness model developed for the working surfaces of parts at degrees of deformation commensurate with the height of the original microprofile; to establish how the degree of microprofile upsetting affects its shape under constrained loading conditions; as well as to estimate the stress state of the microprofile by stress intensity. A numerical model describing the surface microprofile of parts was calculated using the ANSYS Workbench environment. Lead, tin, aluminum, and copper were used as microprofile materials. In addition, microprofile upsetting was computer simulated under constrained loading conditions. The valley bottom was found to rise at a 10–20% microprofile upsetting by 0.213–0.275 mm relative to the original profile height, depending on its material. The relative length of the smoothed microprofile section amounted to 0.786–0.925 mm of its original length. The base angle of the deformed microprofile reached 570 and 800 for copper and lead models, respectively. The depth of valleys ranged from 1.4 mm (23% of the original profile height) for lead models and from 1.8 mm (30% of the original profile height) for copper models. In the case of maximum microprofile upsetting, an increase in the yield strength of microrough material from 10 to 60 MPa contributed to a reduction in the base angle of the deformed microprofile, as well as relative length and the vertical rise of microprofile valleys at their highest point. No interlocking of lateral microprofile surfaces was observed. At a 50% upsetting, the stress state of the microprofile exceeded its ultimate strength by 4–8 times. The shape changes simulated for the microprofile from plastic metallic materials are described. The performed numerical simulation correlates well with the experimental results obtained for lead microprofile models. It is worth noting that the complete smoothing of the microprofile is likely to occur through the rise of valleys and the approaching of its lateral surfaces. The study results can be used for designing and manufacturing valve gate assemblies.

Analysis of the Spatial-Frequency Characteristics of the Photo-Assisted Method of a Quartz Rough Surface Nano-Polishing

The relationship between the spatial-frequency parameters of a rough surface with a random profile, which has a Gaussian form of the correlation function, and the amplitude-frequency characteristics of the electric field created by this surface is determined. The numerical determination of the evanescent field optimal configuration formed near the quartz rough surface in the gaseous medium saturated with chlorine molecules when illuminated from the quartz side has been considered. The finite-element approach is used to solve the Helmholtz two-dimensional vector equation. It was found that at the initial stage of photochemical polishing different electrodynamic conditions are created for the etching process depending on the profile height standard deviation value. In particular, when the standard deviation is less than 1 nm, all surface protrusions, for which the spatial spectrum harmonics of the profile are located in the region of the maximum slope of the spectral function, are most actively etched. This leads to a decrease in the effective width of the spatial spectrum of a rough quartz surface and an increase in its correlation length. Therefore, simultaneously with decreasing the height of the protrusions, the surface becomes flatter. The paper shows the different character of quartz surface nano-polishing process conditions depending on the initial standard deviation of the profile height.

A 3-Level Impaction Technique for Dorsal Reshaping and Reduction Without Dorsal Soft Tissue Envelope Dissection

Background Preservation Rhinoplasty (PR) techniques are continuously evolving in the last two years. Many variations of old-fashioned techniques have been proposed since Daniel coined this term in 2018. Objectives Authors want to describe indications for a new “three level impactions” technique allowing, in selected cases, a complete profile correction and dorsal reduction without the dorsal soft tissue envelope (STE) dissection. Methods Three hundred fifty primary closed rhinoplasty cases were retrospectively studied from January 2018 and October 2019. Age, sex, race and technical details, surgical time and complications have been registered. Ninety-five dorsums were reduced and shaped without dissecting the dorsal soft tissue envelope, combining a 1) swinging door septoplasty with low septal strip resection, 2) endonasal bony cap mosaic osteotomies, and 3) Let down or Push down operation (LDO/PDO). Results All patients showed a dramatic change in profile height and shape without neither dorsal STE dissection nor bony cartilage dorsal tissue resection. The average follow-up time was 14 months (range, 12-16 months). Conclusions In selected patients, dorsum can be preserved without soft tissue envelope dissection. By combining multiple endonasal maneuvers is possible to obtain a dramatic change without dissecting the soft tissue envelope and at the same time avoiding any dorsal tissue resection: mosaic osteotomies for DKA conversion from S to V shaped dorsum, LDO and low septal strip resection for impaction and quadrangular cartilage flap rotation for profile setting. It is a versatile technique in selected patients, which leads to fast recovery and natural results.

Association between obesity and c reactive protein among patients with risk factors for cardiovascular disease

One of the main markers of inflammation is C reactive protein, which is normally raised in patients with myocardial infarction, vascular diseases, stroke or sudden cardiac death. Obesity is associated with a raised CRP level probably due to the cytokine stimulation by the adipose tissues. Elevated CRP with an addition of overweight / obesity is a risk factor for cardiac disorders. Demographic details were taken from 371 patients with cardiovascular risk factors and blood was sent for CRP and lipid profile. Height and weight were noted for the calculation of BMI. The mean age of the males was 48.37± 8.92 years and of the females the same was 45.72 ± 6.23 years, the male to female ratio was 2.1:1. 38.8% of the people were under normal weight, 39% were overweight and 22.1% were obese. A majority of the overweight patients (61.4%) had elevated CRP levels, and 10.3% had clinically raised CRP levels. Amongst the obese patients, 43.9% had clinically raised CRP levels while 35.4% had elevated CRP levels. The is a strong association between the increase in weight among the patients and elevated CRP levels Both these two are not only the risk factors of CVD, but also the cause of depression and reduced quality of life among the individuals.

Kinematic characteristics of the car movement from the top to the calculation point of the marshalling hump

Introduce analytical acceleration formulas that are derived from the classic d'Alembert principle of theoretical mechanics for high-speed sections and sections of retarder positions; show the possibility of determining the instantaneous car speeds in each section of the marshalling hump according to the formulas of elementary physics both for high-speed sections and for sections of retarder positions; provide formulas for determining the time of movement of a car with uniformly accelerated and/or uniformly retarded motion of the car on the inclined part of the hump, as well as in areas of retarder positions. Research methods: The classic d'Alembert principle of theoretical mechanics is widely used in the paper. Main results: For the first time, the results of constructing a graphical dependence of the estimated height of the marshalling hump over the entire length of its profile are presented in the form of a decrease in the profile height of each section of the inclined part in proportion to the slope of the track. The results of constructing graphical dependences on changes in the speed and time of movement of a car along the entire length of the inclined part of the marshalling hump are fundamentally different from the existing methodology, where, for example, curves of medium (rather than instantaneous) speeds of a car are built. The proposed new methodology for calculating the kinematic characteristics of the car movement along the entire length of the hump allows an analysis of the mode of shunting car at the marshalling humps.

A Low-Profile End-Fire Conformal Surface Wave Antenna with Capacitive Feed Structure

A high end-fire gain, low-profile surface wave antenna with capacitive feed structure is presented in this paper. The proposed dielectric-metal surface wave antenna is composed of a dielectric slab that is mounted on a metal carrier and a low-profile feed structure. The feed structure is composed of a monopole radiation pin that is loaded with a circular metal plate and a grounding pin. The profile height of the antenna is only one-tenth of the operating wavelength. With a good end-fire performance and low profile, the antenna is very suitable to be conformally mounted on the surface of flight vehicles. The proposed antenna was designed and manufactured at the center frequency of 6 GHz. Measured results demonstrated that the proposed antenna had a bandwidth of 7.33%, ranging from 5.89 to 6.33 GHz, and the antenna reached a high gain of 9.76 dBi with a length of 122.96 mm (2.45 λ) in the end-fire direction.

Reverse Problem in Surface Texture Analysis—One-Process Profile Modeling on the Basis of Measured Two-Process Profile after Machining or Wear

The method of the base (valley) one-process profile modeling on the basis of the measured two-process profile was developed. The base one-process random profile of the Gaussian ordinate distribution is characterized by the standard deviation of the profile height and the correlation length. The problem of estimation of the correlation length of this one-process profile exists. In the procedure of the correlation length estimation, information about the averaged shape of the autocorrelation functions of many one-process profiles after the same type of machining is required. The correlation length of the base one-process profile can be obtained on the basis of the vertical truncation of the measured two-process profile. The average error of the correlation length estimation was not higher than 7%, while the maximum error was not larger than 14%. This method can be extended to simulate the one-process texture of 3D (areal) surface topography.

A Simplified Method of Detecting Spot Surface Defects by using Quasi-3D Data from a Conventional Road Profiler

It is important to maintain safety and ride quality for toll expressway users in Japan. However, since porous asphalt became the standard road surface, spot defects have gradually spread nationwide. To deal with the problem, this research attempted to develop a less costly but effective way of identifying surface defects. Since transverse data for rutting measurement was the only basic data available for general road profilers, first, quasi-three-dimensional (3D) profile data was successfully obtained by deleting gradient effects on the profiles in both the transverse and longitudinal directions. Among other elements, the standard deviation (SD) of the quasi-3D profile height using spot defect size was best matched for identifying spot defects, including pumping of underlying layer materials of the pavement. To improve the efficiency of detecting spot surface defects, deep learning was examined by converting the SD values into visual images. As a result, it was verified that a simplified classification with basic color information of red, green, and blue gave practically the same engineering judgement. Finally, this method of identifying irregularly emerging target defects using deep learning was validated by relearning the target visuals. A good result with high accuracy was achieved with just 150 images for each defect level. This approach may be universally applied anywhere surface profilers are used.

Generalized-Capon Method for Diff-Tomo SAR Analyses of Decorrelating Scatterers

In synthetic aperture radar (SAR) remote sensing, Differential Tomography (Diff-Tomo) is developing as a powerful crossing of the mature Differential SAR Interferometry and the emerged 3D SAR Tomography. Diff-Tomo produces advanced 4D (3D+Time) SAR imaging capabilities, extensively applied to urban deformation monitoring. More recently, it has been shown that, through Diff-Tomo, identifying temporal spectra of multiple height-distributed decorrelating scatterers, the important decorrelation-robust forest Tomography functionality is possible. To loosen application constraints of the related main experimented full model-based processing, and develop other functionalities, this work presents an adaptive, just semi-parametric, generalized-Capon Diff-Tomo method, first conceived at University of Pisa in 2013, for joint extraction of height and dynamical information of natural distributed (volumetric) scatterers, with its formalization and a series of insights. Particular reference is given to the important functionality of the separation of different decorrelation mechanisms in forest layers. Representative simulated and P-band forest data sample results are also shown. The new Diff-Tomo method is getting a flexible and rich decorrelation-robust Tomography functionality, and is able to profile height-varying temporal decorrelation, for significantly distributed scatterers.

INCREASING THE RANGE OF MEASUREMENTS OF PROFILE HEIGHT IN THE INTERFERENCE PROFILOMETER

Methods for increasing the measurement range of the height of surface profile by the interference profilometer are proposed. The methods are based on using of multiple light sources with different wavelengths. It was shown experimentally that the measurement range increased at least 5 times due to using of two wavelengths, and at least 7 times due to using three wavelengths, while maintaining the resolution of the measurements.