Size Of Irregularities Research Articles

A scaling relationship for the width of secondary deformation around strike-slip faults

Simple mechanical arguments suggest that slip along interlocked, rough faults, damages surrounding rocks. The same arguments require that the scale of secondary damage is proportional to the size of geometric irregularities along the main fault. This relationship could apply at all scales, but has, so far, been difficult to observe at the 10s to 100 s of km scales of large, natural faults, often because large-scale deformation is distributed across wide, complex plate-boundary fault systems, like the San Andreas Fault. The geometry and geology of another large-scale plate-boundary strike slip fault—the Queen Charlotte Fault (QCF)—is, in contrast, especially simple. Here, we show that observations of secondary deformation are well-aligned with predictions of stress variations caused by geometric irregularities along the QCF, suggesting a geometric relationship between primary fault geometry and secondary deformation. The analytic stress solution reveals that the highest stresses and highest likelihood of failure are confined to a zone of influence (ZOI) with a width quantified by ZOI=λ/2π, where λ is the wavelength of geometric variations along the main fault. This simple model is consistent with ∼100-km-scale observations along the QCF and can theoretically be used to predict the width of secondary deformation at all scales.

Polarization jet/SAID and plasma irregularities of various scales

The results of a study of the internal small-scale structure of a polarization jet/SAID using high-frequency data from various satellites are presented. The minimum size of irregularities and the typical internal composition of a stratified subauroral ion drift (SSAID) are confirmed. A two-peak structure has been found, which represents two large strata of the polarization jet/SAID. The shift of strata of electron density and temperature in latitude relative to each other is shown.

The Polarization Jet/SAID and Plasma Irregularities of Different Scales

Results are presented from a study of the internal small-scale structure of the polarization jet/SAID using data from different satellites. The minimum size of irregularities and the typical internal composition of a stratified subauroral ion drift (SSAID) are confirmed. A two-peak structure is found that contains two large strata of the polarization jet/SAID. A shift in latitude is shown for the strata of electron density and temperature, relative to each other.

Simultaneous equatorial plasma bubble observation using amplitude scintillations from GNSS and LEO satellites in low-latitude region

This study estimates the scale sizes of the plasma density irregularities and the longitudinal width associated with equatorial plasma bubbles (EPBs) in equatorial and low-latitude regions. By analyzing amplitude scintillation S4 indices and total electron content (TEC) measured from low earth orbit (LEO) satellite’s beacon signals with 400 MHz and Global Navigation Satellite System (GNSS) L1/E1 signals with 1575.42 MHz, recorded by receivers at the KMITL station in Bangkok, Thailand (geographic; 13.73° N, 100.77°E, magnetic: 7.26°N), we investigate the characteristics of these irregularities. We collected data of 154 LEO satellite pass events during nighttime on 21 disturbed days in four equinoctial months in 2021. Based on the presence or absence of the scintillation effects on GNSS and LEO beacon signals, the events are categorized into four classes to estimate the scale size of the plasma density irregularities. The analysis suggests that events with both GNSS and LEO scintillations, as well as events with GNSS scintillation alone, occur predominantly before midnight assuming the presence of the small-scale size of the irregularities within EPB. However, events with only LEO scintillation occur throughout the whole night and some events are observed before the events with both GNSS and LEO scintillations. Post-sunset LEO scintillation alone may be attributed to the onset of EPBs developing at low altitude, while post-midnight LEO scintillation events near the magnetic equator, observed during periods of low GNSS Rate of TEC Index (ROTI) values, are associated with bottom-side ionospheric irregularities but are not linked with EPB. The findings are consistent with previous researches on the generation and decay of electron density irregularities within plasma bubbles. However, this study provides new insights by using specific data sets and analysis techniques, offering a more comprehensive understanding of the association of LEO scintillations with bottom-side ionospheric irregularities near the magnetic equator, not observed in the ROTI map.Graphical

High Latitude Ionospheric Gradient Observation Results from a Multi-Scale Network.

In this article, a cluster comprised of eight Continuously Operating Reference Station (CORS) receivers surrounding five supplemental test stations located on much shorter baselines is used to form a composite multi-scale network for the purpose of isolating, extracting, and analyzing ionospheric spatial gradient phenomena. The purpose of this investigation is to characterize the levels of spatial decorrelation between the stations in the cluster during the periods with increased ionospheric activity. The location of the selected receiver cluster is at the auroral zone at night-time (cluster centered at about 69.5° N, 19° E) known to frequently have increased ionospheric activity and observe smaller size of high-density irregularities. As typical CORS networks are relatively sparse, there is a possibility that spatially small-scale ionospheric delay gradients might not be observed by the network/closest receiver cluster but might affect the user, resulting in residual errors affecting system accuracy and integrity. The article presents high level statistical observations based on several hundred manually validated ionospheric spatial gradient events along with low level analysis of specific events with notable temporal/spatial characteristics.

Resolving the High‐Latitude Ionospheric Irregularity Spectra Using Multi‐Point Incoherent Scatter Radar Measurements

AbstractTo provide new insights into the relationship between geomagnetic conditions and plasma irregularity scale‐sizes, high‐latitude irregularity spectra are computed using a novel Incoherent Scatter Radar (ISR) technique. This new technique leverages: (a) the ability of phased array Advanced Modular ISR (AMISR) technology to collect volumetric measurements of plasma density, (b) the slow F‐region cross‐field plasma diffusion at scales greater than 10 km, and (c) the high dip angle of geomagnetic field lines at high‐latitudes. The resulting irregularity spectra are of a higher spatiotemporal resolution than what has been previously possible with ISRs. Spatial structures as small as 20 km are resolved in less than 2 minutes (depending on the radar mode). In this work, we focus on Resolute Bay ISR‐North (RISR‐N) observations operating in the “imaginglptight” mode. In addition to having an unprecedented view of the size and occurrence of irregularities as they traverse the polar cap, we find that as the F‐region plasma density decreases below approximately 2.5 × 1010 m−3 at 350 km altitude the spectral power shifts to scale‐sizes lower than 50 km. Additionally, near magnetic local noon, the spectral power shifts to scales greater than 50 km, and from 15 to 6 magnetic local time, the spectral power shifts to scales lower than 50 km. This reflects the role of photoionization dominating high‐latitude ionospheric structuring in the polar cap.

Method for Determining Treated Metal Surface Quality Using Computer Vision Technology.

Computer vision and image processing techniques have been extensively used in various fields and a wide range of applications, as well as recently in surface treatment to determine the quality of metal processing. Accordingly, digital image evaluation and processing are carried out to perform image segmentation, identification, and classification to ensure the quality of metal surfaces. In this work, a novel method is developed to effectively determine the quality of metal surface processing using computer vision techniques in real time, according to the average size of irregularities and caverns of captured metal surface images. The presented literature review focuses on classifying images into treated and untreated areas. The high computation burden to process a given image frame makes it unsuitable for real-time system applications. In addition, the considered current methods do not provide a quantitative assessment of the properties of the treated surfaces. The markup, processed, and untreated surfaces are explored based on the entropy criterion of information showing the randomness disorder of an already treated surface. However, the absence of an explicit indication of the magnitude of the irregularities carries a dependence on the lighting conditions, not allowing to explicitly specify such characteristics in the system. Moreover, due to the requirement of the mandatory use of specific area data, regarding the size of the cavities, the work is challenging in evaluating the average frequency of these cavities. Therefore, an algorithm is developed for finding the period of determining the quality of metal surface treatment, taking into account the porous matrix, and the complexities of calculating the surface tensor. Experimentally, the results of this work make it possible to effectively evaluate the quality of the treated surface, according to the criterion of the size of the resulting irregularities, with a frame processing time of 20 ms, closely meeting the real-time requirements.

Statistical Study on Small‐Scale (≤1,000 km) Density Irregularities in the Inner Magnetosphere

AbstractA statistical survey of small‐scale density irregularities near the magnetic equatorial region of the inner magnetosphere was performed using 7‐year Van Allen Probes data. The cross‐field sizes of these density irregularities are within the order of 1,000 km, corresponding to typical whistler‐mode wave ducts. Spatial distributions on L‐shells and magnetic local times as well as temporal distributions on geomagnetic indices were analyzed using density data in the plasmasphere, the plasmasphere boundary layer (PBL), and the plasma trough. Inside the plasmasphere, the density fluctuations occur predominantly in the night and dawn sectors at L = 2.5–5. They occur far from PBL and show no significant relation with geomagnetic indices. In the PBL at L > 4.5 and the plasma trough, density irregularities are concentrated in post‐midnight during quiet times and extend to all night sectors during active times. Density fluctuation values in the PBL are much higher than those in the other two regions. We discuss connections of irregularities deep inside the plasmasphere to ionospheric electric field disturbances and those in and near the PBL to interchange instabilities.

Application of a non-invasive measurement technique to detect anomalies in frescoes at the US Capitol

Abstract Delamination is one of the most common issue that can affect frescoes and wall painting in general. Non-destructive techniques (NDT) are considered an effective analysis method for frescoes conservation status detection. The objective of this work was to determine the structural integrity of plaster in the United States Capitol Building through structural vibration analysis. The plaster was excited with sound, causing it to vibrate at a miniscule level. The resulting vibrations were measured using a laser vibrometer and then utilized to reveal the location and size of unseen irregularities in the structure. More than 50 individual scans were performed and analyzed using scanning laser Doppler vibrometer (LDV). The analysis identified many anomalies and assessed the status of some areas that were intact. This procedure was performed on each of the frescoes adorning the walls and ceiling of the rooms to discover areas where the painted plaster has lost adherence to the underlying architecture. The frescos were classified into three categories: intact, anomalous, in need of further analysis. A comparison with data recorded in 2004 of the same frescoes has been also performed.

Building a model of dressing the working surfaces of wheels during the two-side grinding of round end faces at CNC machines

This paper reports the spatial mathematical modeling of the process of dressing the working surface of grinding wheels for implementing the double-sided grinding of the ends of cylindrical components. Parts with high-precision end surfaces that are commonly used include bearing rollers, piston fingers, crosspieces of cardan shafts, and others. The geometric accuracy of surfaces is ensured by simultaneously grinding the ends at two-sided end-grinding machines with crossed axes of the part and wheels that operate under a self-blunting mode. Before starting the machining, the wheels are dressed in a working position. Moreover, the total orientation angle of the tools is selected subject to the condition of uniform distribution of allowance along the rough sections of wheels. Dressing involves a single-crystal diamond tool with a variable feed. That ensures different development of the surface of abrasive tools, which prolongs their operating time between dressings and improves overall stability. The constant size of micro irregularities at the calibration site enhances the quality of machining. The calibration site is made in the form of a straight line belonging to the plane that passes through the axis of rotation of the wheel and is perpendicular to the plane of the machined part. Based on the spatial mathematical models of the processes of removal of allowance and shape formation when dressing the wheel, the surface of the grinding wheel was investigated. Mathematical models for shaping the ends of parts when grinding with wheels with conical calibration sites have been proposed; it is shown that when applying the proposed machining scheme, there is no geometric error in the size of the part. In addition, due to the uniform distribution of the allowance along the rough area of the wheel, the quality of the surface layer of the ends of parts increases. The devised method for dressing the working surface of wheels could be used to grind the ends of non-circular components.

Formation of effective concentration of film forming superhydrophobic coatings based on silicon dioxide

The object of research is the hydrophobization of a coating based on styrene-acrylic copolymer and cellulose acetate butyrate with pyrogenic silicon dioxide. The hydrophobicity or hydrophilicity of a surface depends mainly on the chemical structure of the surface and its roughness. A relief hydrophilic surface will be wetted much more easily than a flat surface of the same material, and vice versa – an increase in the roughness of a hydrophobe is accompanied by a more pronounced repulsion of water. The size and number of irregularities significantly affect the wetting characteristics of the investigated surface. The combination of low surface energy and relief structure forms a superhydrophobic surface. Such surfaces have found application in self-cleaning, frost-resistant, antifriction, electrically conductive and oil-sorbing coatings. In this work, styrene-acrylic copolymer and cellulose acetate butyrate were used as a film former. Pyrogenic silicon dioxide Aerosil R 972, which was hydrophobized with dimethyldichlorosilane, was used as a nanofiller. In this work, the compositions were applied to laboratory glasses by dip coating. The determination of surface energy was carried out using glycerin and diiodomethane. The hydrophobic properties of the coatings were evaluated by measuring the contact angles with water using a goniometer. The analysis of the morphological structure of the coating surface with photographs of a scanning electron microscope has been carried out. The energy state of the surface of the created superhydrophobic coatings has been determined and their surface energies have been calculated using the technique based on the Owens-Wendt model. The process of hydrophobization of polymer-based coatings is investigated, which occurs both due to chemical modification with the introduction of silicon dioxide and due to the creation of nanoroughness of the surface layer of the coatings. The dependences of this process on materials are investigated using an electron microscope and the determination of their surface energy depending on the SiO2 filling. The values of the critical concentration of the modifier for the transition of polymers to the superhydrophobic state have been determined. As a result, the influence of polymer crystallinity on hydrophobization was determined by comparing changes in the surface energy of materials during their modification.

Антикоррозионные и гидрофобные свойства пленок карбоновых кислот на поверхности алюминиевого сплава Д16

The production possibility of protective films of higher carboxylic (lauric, stearic (SA), oleic and linolenic) acids on a laser-textured surface of an aluminum alloy D16 is discussed. It is shown that such a modification leads to superhydrophobization (SHP) of the alloy surface. The most optimal type of laser processing has been determined: laser power is 12 W and the pass speed is 1000 mm / s. Profilometric measurements determined the average size of surface irregularities which is 6,47 microns. The degradation results of the SHP state in an aqueous solution of 0,05 M NaCl indicate greater stability of films formed from SA solutions. The protective ability of the coatings was evaluated by polarization measurements and corrosion tests in a salt chamber. It was found that films formed from an SA solution had the best anticorrosive properties. According to polarization measurements, an increase in ΔEpt = 220 mV, and the time of the first corrosion damage appears τcor = 384 h.

Research and development of anti-maceration laparoscopic surgical cotton swabs

Introduction Although laparoscopic cotton swabs have been used in procedures such as blunt tissue dissection and elevation of organs, fluid maceration is widely known to reduce their original performance. Thus, we developed an anti-maceration laparoscopic surgical cotton swab that is expected to solve this problem by coating the cotton swab with water-resistant resin. This study aimed to determine whether anti-maceration cotton swabs perform better than conventional products. Material and methods Fine surface shape analysis of cotton swabs was performed using microfocus X-ray computed tomography, and changes due to fluid absorption of the anti-maceration cotton swabs and pre-existing products were quantitatively compared. As indices, the degree of expansion by maceration and SMD (surface roughness index of the fiber industry showing the size of irregularities on the surface) were evaluated. Results The degree of expansion was lower in anti-maceration swabs than in conventional products. Maceration reduced SMD in existing products, whereas the SMD in anti-maceration cotton swabs did not change. Conclusions Anti-maceration cotton swabs have a superior performance over conventional products.

Influence of Growth Defects on the Oxidation Resistance of Sputter-Deposited TiAlN Hard Coatings

This paper reports the results of an investigation of the oxidation of a sputter-deposited TiAlN hard coating in air at temperatures of 800 and 850 °C for times ranging from 15 min to 2 h. The study is focused on the role of growth defects in the oxidation process. The mechanism of oxidation at the site of the defect was studied on cross-sections made by the consecutive sectioning of oxidized coatings with the FIB technique. We found that in the early stage of oxidation, the locally intense oxidation always starts at such defects. Although the growth defects reduce the oxidation resistance of the coating locally, we believe that they do not have a decisive influence on the global oxidation resistance of the coating. There are several reasons for this. The first is that the surface area covered by growth defects is relatively low (less than 1%). Secondly, the coating is permeable only at those defects that extend through the entire coating thickness. Thirdly, the permeability at the rim of some defects strongly depends on the density of pores at the rim of defects and how open they are. The size and density of such pores depend on the shape and size of topographical irregularities on the substrate surface (e.g., seeds, pits), which are responsible for the formation of growth defects. We also found that oxidation of the TiAlN coating is accelerated by oxygen and titanium diffusion through the pores formed by crystal grain growth in the outer alumina overlayer. Such pores are formed due to the compressive stresses in the Ti-rich oxide layer, which are caused by the large difference in molar volumes between the oxide and nitride phases.

The influence of the pavement surface texture on the Pendulum Test Value

The article deals with the problem of finding a relation between surface texture and skid resistance represented by the Pendulum Test Value. For the texture measurements was used a new device that can capture surface irregularities up to the microtexture level. Besides Pendulum Test Values were also evaluated standard roughness parameters as well as the Mean Profile Depth widely used for pavement surface macrotexture evaluation. The texture parameters were evaluated for both macro- and micro-texture of all tested surfaces. Two groups of surfaces were measured. The first group, represented by reference surfaces with known parameters, was used for evaluation of the reliability of new device as well as for determining the relation between microtexture and pendulum test value. The second group was represented by asphalt mixture specimens designed to create various surfaces with different parameters of both macrotexture and microtexture. The obtained results show that there is no unambiguous direct relation between the size of irregularities and skid resistance. That means that high values of both macro and microtexture won’t have to necessarily mean a high level of friction. The proper size and proportion of both parts in their optimal combination are needed.

Macrorelief and chemical composition of a surface of details made of stainless steels after electrochemical polishing in a non-stationary electrolysis mode

This paper is dedicated to study of the macrorelief and the chemical composition of the surface of the details made of stainless steel after the electrochemical polishing in the nonstationary electrolysis mode with usage of a scanning electron microscope JEOL JSM-6510A. We presented images of the surface of samples under test and spectrograms of quantity distribution of chemical elements in their near surface layers after a processing in different technological modes (process phases). We made a calculation of sizes of the surface irregularities and an average number of chemical elements distribution in the near surface layers of the samples under test. We presented diagrams of a dependence of the surface irregularities sizes of the samples under test on the technological modes of the processing.

Rigidity and Irregularity Effect on Surface Wave Propagation in a Fluid Saturated Porous Layer

The propagation of surface waves in a fluid- saturated porous isotropic layer over a semi-infinite homogeneous elastic medium with an irregularity for free and rigid interfaces have been studied. The rectangular irregularity has been taken in the half-space. The dispersion equation for Love waves is derived by simple mathematical techniques followed by Fourier transformations. It can be seen that the phase velocity is strongly influenced by the wave number, the depth of the irregularity, homogeneity parameter and the rigid boundary. The dimensionless phase velocity is plotted against dimensionless wave number graphically for different size of rectangular irregularities and homogeneity parameter with the help of MATLAB graphical routines for both free and rigid boundaries for several cases. The numerical analysis of dispersion equation indicates that the phase velocity of surface waves decreases with the increase in dimensionless wave number. The obtained results can be useful to the study of geophysical prospecting and understanding the cause and estimating of damage due to earthquakes.

Properties of nematic LC planar and smoothly-irregular waveguide structures: research in the experiment and using computer modeling

Nematic liquid crystal planar and smoothly-irregular waveguide structures were studied experimentally and by the computer modeling. Two types of optical smoothly-irregular waveguide structures promising for application in telecommunications and control systems are studied by numerical simulation: liquid crystal waveguides and thin film solid generalized waveguide Luneburg lens. Study of the behavior of these waveguide structures where liquid crystal layer can be used to control the properties of the entire device, of course, promising, especially since such devices are also able to perform various sensory functions when changing some external parameters, accompanied by a change in a number of their properties. It can be of interest to researchers not only in the field of the integrated optics but also in some others areas: nano-photonics, optofluidics, telecommunications, and control systems. The dependences of the attenuation coefficient (optical losses) of waveguide modes and the effective sizes (correlation radii) of quasi-stationary irregularities of the liquid-crystal layers on the linear laser radiation polarization and on the presence of pulse-periodic electric field were experimentally observed. An estimate was made of the correlation radii of liquid-crystal waveguide quasi-stationary irregularities. The obtained results are undoubtedly important for further research of waveguide liquid crystal layers, both from the theoretical point of view, and practical – in the organization and carrying out new experimental researches, for example, when developing promising integrated-optical LC sensors.

Influence of reduction quality on functional outcome and quality of life in treatment of tibial plafond fractures: a retrospective cohort study

BackgroundThe aim of the study was to evaluate the impact of reduction quality, using intraoperative 3D imaging, on quality of life and functional outcome in the operative treatment of tibial plafond fractures.MethodsA group of patients with tibial plafond fractures was re-examined. The operative treatment was performed between September 2001 and October 2011. The follow-up examination was at least 2 years after the final surgical procedure. Final reduction result was assessed intraoperatively using a mobile 3D C-arm. A categorization with regard to descriptive parameters as well as type and size of joint surface irregularities was performed. Follow-up results were evaluated using: Olerud and Molander (O & M) score, Short-Form-36 (SF-36) score, movement deficit, Kellgren and Lawrence grade of osteoarthritis, and pain intensity.Results34 patients with operatively treated tibial plafond fracture could be re-examined. Reduction quality had the greatest influence on functional result measured by the O & M score (p = 0.001) and the PCS domain of the SF-36 score (p = 0.018).Significant differences with regard to O & M score (p = 0.000), SF-36 score (p = 0.001 to p = 0.02; without MCS domain), movement deficit (p = 0.001), grade of osteoarthritis (p = 0.005) and pain (p = 0.001) could be verified under consideration of the reduction quality. The group with the anatomically more accurate reduction also showed a better result for clinical follow-up and quality of life. Furthermore, it is not the type of joint surface irregularity that is always decisive, but rather the size.ConclusionsDespite other relevant factors, it appears that reduction quality –which can be analyzed with intraoperative 3D imaging– plays the most important role in postoperative quality of life and functional outcome. Corrections should therefore be performed on joint surface irregularities with a size above 2 mm.

FORMATION OF GIS «AUTOMOBILE ROAD» METADATA BASES FOR MONITORING AND AUTOMOBILE ROAD CADASTRE

Problem. This article discusses the approach to the formation of a database of geographic information system (GIS) «Road» for monitoring and cadastre of roads. Geo-information systems are becoming increasingly used in all areas of activity, including road construction. Today in Ukraine there is no GIS «Road» formed and ready for use. Therefore, the issue of forming a database for GIS, considered in this article, is very relevant. Goal. The purpose of the study is to create a database of GIS «Road» for monitoring and cadastre of roads, taking into account the evenness of the road surface. Methodology. An approach to the formation of a database of the GIS «Road» is proposed by including in the database the number, size and shape of the surface irregularities. The scheme of interaction between a moving pneumatic wheel of a car and irregularities on the road surface is considered. Results. The analysis of existing irregularities on the pavement of the exploited pavements was carried out and typical forms of irregularities were determined. Calculated dynamic factors caused by irregularities of various shapes and various parameters when driving a car. Originality. An approach is proposed to determine the magnitude of the additional load on the pavement when overcoming the unevenness of the road surface of various shapes. Practical value. The formation of the GIS «Road» database, taking into account the flatness of the coatings in use, will make it possible to predict the condition of the road surface in the future, as well as estimate the cost of the road as a property.