Control of Deformation of Elastic Polymer-Abrasive Circles at their Wear

The article is devoted to the study of the wear intensity of elastic polymer-abrasive circles when processing the surfaces of parts made of high-strength aluminum alloys. Empirical dependencies of wear on cutting speed and tool deformation are obtained, on the basis of which method of tool deformation correction with long-term, continuous surface treatment is proposed. In practice, such a procedure is necessary due to the loss of process performance that occurs due to the reduction of tool deformation due to wear. The proposed technique allows to effectively control the finishing process as the tool is worn out.

A prominent maximum in surface ozone concentration during winter months at Pune (India)

ABSTRACT. Concentration of ozone near the ground has been recorded at Pune (India) since 1972 with the help of a continuous surface ozone recorder using electro-chemical sensor. The analysis of the records of winter season indicates a sharp rise in ozone amount in the forenoon around 1000 to 1200 LST. Prior to 1985 this forenoon: higher value in surface ozone concentration was followed by another maximum in the afternoon hours coinciding with the maximum temperature epoch of the day. After 1985 the surface ozone data indicates that the forenoon peak value has become invariably higher than the afternoon value. Due to increasing concentration of anthropogenic gases in the atmosphere there is a possibility of photochemical production of ozone in the troposphere which may give rise to higher surface ozone values, when the meteorological conditions are favourable for the accumulation of such gases which are involved in ozone production.

RESEARCH OF INNOVATIVE MECHANISMS CREATION OF MODERN BUILDING MATERIALS FOR IMPROVEMENT OF PRODUCTION PROCESSES

Purpose. To reveal the mechanism of formation of contact zones and purposeful choice of mastic composition and its substantiation on the basis of revealing of regularities of interrelations "mastic composition – waterproofing resource". Methodology. The sequence of changes in the technical condition of roofing materials, which varies from normal without damage to emergency with intermediate satisfactory and unsuitable for normal operation depending on the specific damage and leakage of the roof affects the definition of conventional material resources, means and methods of arrangement and arrangements. roofs, as well as the mechanism and kinetics of loss of serviceability are a key factor in improving the whole set of measures aimed at making technology competitive. Results. Technologies of repair of point and local damages in the form of cracks, breaks, exfoliations which are carried out by cutting and the subsequent gluing of pieces of cloths on the prepared sites with filling, allow to receive short-term results. Elimination of continuous surface damage by applying an additional layer of rolled or mastic material is associated with the inevitable preservation in the lower layers of the causes of premature loss of operational functions of the coating. The results provide an opportunity to perform non-dismantling repair and restoration work using purposefully proposed repair composition with the minimum possible cost of resources and a high degree of mechanization. The developed technology is based on the ability of the used repair composition to impregnate and saturate the adjacent surfaces with ingredients that can eliminate damage of a certain type and return the coating or protective layer of the initial waterproofing potential and strengthen it. Originality. Substantiation of possibilities of use of the residual waterproofing resource of the existing soft roof by its saturation with ingredients of the offered repair composition. Practical value. It is possible to effectively use, restore and enhance the residual waterproofing potential of bitumen-roofing roof by pneumatic spraying repair composition of the developed composition.

Development of smartphone-based semi-prepared runway operations (SPRO) models and methods

The U.S. Army Engineer Research and Development Center (ERDC) has developed a method for predicting surface friction response by use of ground vehicles equipped with deceleration-based measurement devices. Specifically, the ERDC has developed models and measurement methods between the Findlay Irvine Mk2 GripTester and a variety of deceleration measurement devices: Bowmonk AFM2 Mk3, Xsens MTi-G-710, two Android smartphones, and two iOS smartphones. These models show positive correlation between ground vehicle deceleration and fixed-slip surface continuous surface friction measurement. This effort extends prior work conducted by the U.S. Army ERDC in developing highly correlative models between the Findlay Irvine Mk2 GripTester and actual C-17 braking deceleration, measured via the runway condition rating (RCR) system. The models and measurement methods detailed here are of considerable use to semi-prepared airfield managers around the world needing to measure safe landing conditions following inclement weather. This work provides the tools necessary for airfield managers to quantify safe landing conditions for C-17 aircraft by using easily obtainable equipment and simple test standards.

Modelling of faults in LoopStructural 1.0

Without properly accounting for both fault kinematics and observations of a faulted surface, it is challenging to create 3D geological models of faulted geological units. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological interfaces are poorly characterised by sparse datasets are particular challenges. There are two existing approaches for incorporating faults into geological surface modelling. One approach incorporates the fault displacement into the surface description but does not incorporate fault kinematics and in most cases will produce geologically unexpected results such as shrinking intrusions, fold hinges without offset and layer thickness growth in flat oblique faults. The second approach builds a continuous surface without faulting and then applies a kinematic fault operator to the continuous surface to create the displacement. Both approaches have their strengths; however, neither approach can capture the interaction of faults within complicated fault networks, e.g. fault duplexes, flower structures and listric faults because they either (1) impose an incorrect (not defined by data) fault slip direction or (2) require an over-sampled dataset that describes the faulted surface location. In this study, we integrate the fault kinematics into the implicit surface, by using the fault kinematics to restore observations, and the model domain prior to interpolating the faulted surface. This new approach can build models that are consistent with observations of the faulted surface and fault kinematics. Integrating fault kinematics directly into the implicit surface description allows for complexly faulted stratigraphy and fault–fault interactions to be modelled. Our approach shows significant improvement in capturing faulted surface geometries, especially where the intersection angle between the faulted surface and the fault surface varies (e.g. intrusions, fold series) and when modelling interacting faults (fault duplex).

Beyond Vertical Point Accuracy: Assessing Inter-pixel Consistency in 30 m Global DEMs for the Arid Central Andes

Quantitative geomorphic research depends on accurate topographic data often collected via remote sensing. Lidar, and photogrammetric methods like structure-from-motion, provide the highest quality data for generating digital elevation models (DEMs). Unfortunately, these data are restricted to relatively small areas, and may be expensive or time-consuming to collect. Global and near-global DEMs with 1 arcsec (∼30 m) ground sampling from spaceborne radar and optical sensors offer an alternative gridded, continuous surface at the cost of resolution and accuracy. Accuracy is typically defined with respect to external datasets, often, but not always, in the form of point or profile measurements from sources like differential Global Navigation Satellite System (GNSS), spaceborne lidar (e.g., ICESat), and other geodetic measurements. Vertical point or profile accuracy metrics can miss the pixel-to-pixel variability (sometimes called DEM noise) that is unrelated to true topographic signal, but rather sensor-, orbital-, and/or processing-related artifacts. This is most concerning in selecting a DEM for geomorphic analysis, as this variability can affect derivatives of elevation (e.g., slope and curvature) and impact flow routing. We use (near) global DEMs at 1 arcsec resolution (SRTM, ASTER, ALOS, TanDEM-X, and the recently released Copernicus) and develop new internal accuracy metrics to assess inter-pixel variability without reference data. Our study area is in the arid, steep Central Andes, and is nearly vegetation-free, creating ideal conditions for remote sensing of the bare-earth surface. We use a novel hillshade-filtering approach to detrend long-wavelength topographic signals and accentuate short-wavelength variability. Fourier transformations of the spatial signal to the frequency domain allows us to quantify: 1) artifacts in the un-projected 1 arcsec DEMs at wavelengths greater than the Nyquist (twice the nominal resolution, so > 2 arcsec); and 2) the relative variance of adjacent pixels in DEMs resampled to 30-m resolution (UTM projected). We translate results into their impact on hillslope and channel slope calculations, and we highlight the quality of the five DEMs. We find that the Copernicus DEM, which is based on a carefully edited commercial version of the TanDEM-X, provides the highest quality landscape representation, and should become the preferred DEM for topographic analysis in areas without sufficient coverage of higher-quality local DEMs.

Fabrication of Multifocal Microlens Array by One Step Exposure Process

Microlenses can be widely used in integrated micro-optical systems. However, in some special applications, such as light field imaging systems, multifocal microlens arrays (MLA) are expected to improve imaging resolution. For the fabrication of multifocal MLA, the traditional fabrication method is no longer applicable. To solve this problem, a fabrication method of multifocal MLA by a one step exposure process is proposed. Through the analyses and research of photoresist AZ9260, the nonlinear relationship between exposure dose and exposure depth is established. In the design of the mask, the mask pattern is corrected according to the nonlinear relationship to obtain the final mask. The continuous surface of the multifocal MLA is fabricated by the mask moving exposure. The experimental results show that the prepared multifocal MLA has high filling factor and surface fidelity. What is more, this method is simple and efficient to use in practical applications.

Crystalline Silicon Spalling as a Direct Application of Temperature Effect on Semiconductors’ Indentation

Kerf-less removal of surface layers of photovoltaic materials including silicon is an emerging technology by controlled spalling technology. The method is extremely simple, versatile, and applicable to a wide range of substrates. Controlled spalling technology requires a stressor layer, such as Ni, to be deposited on the surface of a brittle material; then, the controlled removal of a continuous surface layer can be performed at a predetermined depth by manipulating the thickness and stress of the Ni layer, introducing a crack near the edge of the substrate, and mechanically guiding the crack as a single fracture front across the surface. However, spalling Si(100) at 300 K (room temperature RT) introduced many cracks and rough regions within the spalled layer. These mechanical issues make it difficult to process these layers of Si(100) for PV, and in other advanced applications, Si does not undergo phase transformations at 77 K (Liquid Nitrogen Temperature, LNT); based on this fact, spalling of Si(100) has been carried out. Spalling of Si(100) at LNT improved material quality for further designed applications. Mechanical flexibility is achieved by employing controlled spalling technology, enabling the large-area transfer of ultrathin body silicon devices to a plastic substrate at room temperature.

The Effect of Carboxymethyl Glucomannan Concentration on the Properties of Glucomannan-Chitosan Hydrogel for Lactobacillus acidophilus FNCC 0051 Encapsulation

The effect of porang (Amorphophallus oncophyllus) glucomannan concentration on the properties of glucomannan-chitosan hydrogel was investigated for Lactobacillus acidophilus FNCC 0051 encapsulation. The spherical shape with a continuous surface of the particle was self-assembly formed. The increase of glucomannan concentration from 0.3 to 0.9 % smoothly increased their small particle size from 1.08 ± 0.02 µm to 2.12 ± 0.00 µm and no significant change on the positive zeta potential values. The polydispersity indexes with the value between 0.4 to 0.5 were categorized as uniform particles. However, these values were higher compared to other studies which used konjac glucomannan-chitosan as the hydrogel materials. The encapsulation study with Lactobacillus acidophilus FNCC 0051 showed that the highest value was achieved when the same ratio of glucomannan and chitosan was applied (0.5 %). The viability study proved the perfect protection of hydrogel during 56 days of cold storage and pasteurization treatment with the cell viabilities of 100 % and 58.13 ± 18.5 %, respectively. HIGHLIGHTS Glucomannan concentration influenced particle size and encapsulation efficiency of hydrogel Hydrogel was potential as acidophilus carrier in the gut due to its pH sensitivity Hydrogel had continuous surface to provide a stronger physical barrier for the acidophilus against harsh environment Hydrogel proved well protection of acidophilus during pasteurization and cold storage GRAPHICAL ABSTRACT