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Статті в журналах з теми "Sub-surface profile"
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Wahid, Nur Syahirah, Norihan Md Arifin, Mustafa Turkyilmazoglu, Mohd Ezad Hafidz Hafidzuddin, and Nor Aliza Abd Rahmin. "MHD Hybrid Cu-Al2O3/ Water Nanofluid Flow with Thermal Radiation and Partial Slip Past a Permeable Stretching Surface: Analytical Solution." Journal of Nano Research 64 (November 2020): 75–91. http://dx.doi.org/10.4028/www.scientific.net/jnanor.64.75.
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The influence of velocity slip and thermal radiation effects on the magnetohydrodynamic hybrid Cu-Al2O3/water nanofluid flow over a permeable stretching sheet is reported in this paper. The similarity transformation is adopted to reduce the partial differential equations to the ordinary differential equations. Exact analytical method is implemented to solve the problem. Maple program is used to facilitate the calculation process. The new additional effects which are the velocity slip and thermal radiation effects are considered towards the model to scrutinize the impacts. The effects of various parameters towards the velocity and temperature profiles are demonstrated through graphs, meanwhile the skin friction coefficient and the local Nusselt number are exhibited through the tabulation of data. The existence of velocity slip reduced the velocity profile but enhanced the temperature profile. The thermal radiation effect has increased the temperature profile. The heat transfer rate are enhanced for the case of hybrid nanofluid compared to the mono nanofluid.
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KIM, DONG-YEOL, HAK-JOON KIM, SUNG-JIN SONG, and SUNG D. KWON. "EVALUATION OF SUB-SURFACE MATERIAL PROPERTIES USING MINIMUM REFLECTION PROFILES METHOD." Modern Physics Letters B 22, no. 11 (May 10, 2008): 983–88. http://dx.doi.org/10.1142/s0217984908015711.
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Backscattered Rayleigh waves from the surface and/or sub-surface of specimens can be changed by scatterers such as micro-cracks, grain boundaries and surface roughness as well as by variations in material properties. In fact, rough surface generates higher energy of backscattered Rayleigh wave than smooth one. So, it is strongly needed to have a quantitative method to evaluate the variation of material properties only. To address such a need, we propose a new method, named as "minimum reflection profile" which measures energy variation of reflected waves from the surface of specimens as changing the angle of incident wave from normal to beyond Rayleigh angle in a pitch-catch immersion setup. Because of minimum reflection profile is less sensitive to roughness of surface than backward radiation profile. Also, we explore performance of the minimum reflection profiles by evaluating the sub-surface material properties of well known materials with various material properties.
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Lindsey, Kevin, Stuart T. Smith, and Colin J. Robbie. "Sub-Nanometre Surface Texture and Profile Measurement with NANOSURF 2." CIRP Annals 37, no. 1 (1988): 519–22. http://dx.doi.org/10.1016/s0007-8506(07)61691-6.
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Invernizzi, Laurent, Nader Sadeghi, Florent P. Sainct, and Philippe Guillot. "Study of He + 0.2% O2 plasma jet impinging on liquid surface from He(23S1) metastable atoms density measurements." Plasma Sources Science and Technology 31, no. 3 (March 1, 2022): 035002. http://dx.doi.org/10.1088/1361-6595/ac4e21.
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Abstract This work presents spatial variations of the helium He(23S1) metastable atom absolute densities in a plasma jet at atmospheric pressure in He + 0.2% O2 gas mixture impinging on a liquid target. The plasma jet is ignited with 6 kV pulses of 2.5 μs duration and 8 ns rise and fall times at 20 kHz repetition rate. Streamers are created in both rising and falling fronts of the high voltage (HV). From Abel inversion of the line averaged absorbance of 1083 nm helium line, measured by laser absorption spectroscopy, the radial profiles of He(23S1) density along the plasma jet are deduced in two sources with different residence time of the gas within the discharge volume, having three different outlet tube diameters and with two gas flow rates. The metastable densities up to ∼3 × 1013 cm−3 have been measured. The radial profile remained always axially centered for the 1.5 mm outlet tube and with 0.5 slm for the larger diameter tubes. But in this later tubes and with 2 slm gas flow rate, the profile changed from a ring shape at the tube exit to axially centered when increasing the distance from the tube edge. In the rising front of the HV, the ring profile of He(23S1) density in the tube exit is attributed to the shape of the electric field, produced by the applied HV to the electrode wrapped around the dielectric tube. In the falling front of the HV, the electric field results from electrons deposited on the inner surface of the dielectric tube and positive ions accumulated on the surface of liquid during the 2.5 μs duration of the HV pulse. The influence of oxygen by-products formed in the plasma volume (O, O2(Δ), O3, positive and negative oxygen ions) on the dynamic of the plasma jet are analyzed.
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Kang, W. T., M. N. Derani, and M. M. Ratnam. "Effect of Vibration on Surface Roughness in Finish Turning: Simulation Study." International Journal of Simulation Modelling 19, no. 4 (December 5, 2020): 595–606. http://dx.doi.org/10.2507/ijsimm19-4-531.
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This paper presents the results of simulation analyses carried out to investigate the effect of adding controlled vibration of varying amplitudes and frequencies onto simulated workpiece profiles on surface roughness. The surface profiles were generated using the nose edge image of a real cutting tool insert at various stages of wear. The invariant moment sub-pixel edge detection method was used to extract the precise tool nose profile. The extracted nose profile was duplicated 20 times to generate the simulated workpiece profile. Vibration signals in the form of sine waves of amplitudes 0 to 50 % of the peak-to-valley height of the original workpiece profile and various frequencies were added to the simulated profile. Noise signals emanating from real machining were also added to the original profile to investigate their effect on roughness. The simulation study has shown that average roughness may increase continuously or fluctuate randomly depending on the magnitude of vibration added to the vibration-free workpiece profile. In the absence of vibration, the surface roughness of the workpiece decreases due to flattening effect of the tool nose during early stages of tool wear.
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Dartnell, L. R., L. Desorgher, J. M. Ward, and A. J. Coates. "Martian sub-surface ionising radiation: biosignatures and geology." Biogeosciences Discussions 4, no. 1 (February 9, 2007): 455–92. http://dx.doi.org/10.5194/bgd-4-455-2007.
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Abstract. The surface of Mars, unshielded by thick atmosphere or global magnetic field, is exposed to high levels of cosmic radiation. This ionizing radiation field is deleterious to the survival of dormant cells or spores and the persistence of molecular biomarkers in the subsurface, and so its characterisation is of prime astrobiological interest. Previous research has attempted to address the question of biomarker persistence by inappropriately using dose profiles weighted specifically for cellular survival. Here, we present modelling results of the unmodified physically absorbed radiation dose as a function of depth through the Martian subsurface. A second major implementation of this dose accumulation rate data is in application of the optically stimulated luminescence technique for dating Martian sediments. We present calculations of the dose-depth profile from galactic cosmic rays in the Martian subsurface for various scenarios: variations of surface composition (dry regolith, ice, layered permafrost), solar minimum and maximum conditions, locations of different elevation (Olympus Mons, Hellas basin, datum altitude), and increasing atmospheric thickness over geological history. We also model the changing composition of the subsurface radiation field with depth compared between Martian locations with different shielding material, determine the relative dose contributions from primaries of different energies, and briefly treat particle deflection by the crustal magnetic fields.
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Aras, Eyyup. "Tracing sub-surface swept profiles of tapered toroidal end mills between level cuts." Journal of Computational Design and Engineering 6, no. 4 (April 18, 2019): 629–46. http://dx.doi.org/10.1016/j.jcde.2019.04.003.
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Abstract Development of closed-form solutions and algorithms for constructing sub-surface swept profiles (SWP) of toroidal and conical bodies is presented in this paper. While the problem of identifying the entire SWP of such surfaces has been extensively investigated in extant studies, construction of subsurface SWPs has rarely been addressed despite the subject being of great significance to machining process employing nonstandard-shaped NC tools. Torus shapes considered in extant literature are restricted to the fourth quadrant of a tube cross section. In industrial applications, however, profile cutters contain different regions of a toroidal surface. To identify SWP elements in the proposed study, a single analytical expression in one variable has been deduced using two moving frames. The basic idea behind such a formulation is to employ the one-to-many strategy, which greatly reduces the computational cost and effort. Algorithms to identify feasible domains of SWP parameters at each level cut, where toroidal and conical surfaces meet, have also been proposed in this study. This is important, since cutting a tool surfaces along the rotation axis divides SWP-parameter domains into non overlapping sets of intervals that must be addressed for each tool posture. In addition, this study demonstrates that for certain tool postures, while C1 continuity between sub-surfaces is satisfied, the SWP connectivity is lost at some points. To locate these so called singular-characteristic points, some precomputation steps have been performed. Lastly, several factors affecting the smoothness of SWPs have been identified and discussed. Highlights Closed form solutions have been derived for constructing the sub-swept profiles of toroidal tools. Three algorithms have been presented to identify the feasible domains of swept profile parameters. In order to locate the singular-characteristic points some precomputation steps have been carried out. Finally, several factors, affecting the smoothness of the swept profiles, have been identified.
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Zhang, Chang Juan, Chuan Shao Liu, and Bo Zhao. "Experimental Study on Surface Quality of Al2O3 Engineering Ceramics in Ultrasonic Drilling and Grinding." Applied Mechanics and Materials 42 (November 2010): 457–60. http://dx.doi.org/10.4028/www.scientific.net/amm.42.457.
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Engineering ceramics have been widely used in recent years because of its excellent performances. However, the high hardness and brittleness make it very difficult to process with high efficiency and good quality, especially in precision and ultraprecision machining. Therefore, a method of ultrasonic drilling and grinding is provided to the hole machining of Al¬2O3 engineering ceramics. In the paper, with different machining parameters, the surface roughness of micro hole in ultrasonic and traditional drilling and grinding is compared and analyzed. Moreover, the surface micro profile and the wear condition of drilling-grinding tool in ultrasonic and traditional drilling and grinding are observed through SEM. Finally, it is concluded that ultrasonic drilling and grinding is a kind of high efficient processing method adapting to micro holes of hard - brittle materials etc.
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Rahman, A. Azizur, Emroj Hossian, Hetal Vaishnav, Jayesh B. Parmar, Arnab Bhattacharya, and Arun Sarma. "Synthesis and characterization of Cu3SbS4 thin films grown by co-sputtering metal precursors and subsequent sulfurization." Materials Advances 1, no. 9 (2020): 3333–38. http://dx.doi.org/10.1039/d0ma00574f.
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X-ray diffraction profile, Raman and optical absorption spectra, and surface morphology of phase-pure Cu3SbS4 films grown at 425 °C by co-sputtering metal precursors and subsequent sulfurization.
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H S, Nithin, Pradeep D G, Nishchitha K M, Mahantayya Mathapati, Chikodi ., and Anand Babu K. "Comparative study on high temperature oxidation behaviour of CoCrAlY coatings by various reinforcement composition profile analysis." Journal of Mines, Metals and Fuels 69, no. 12A (April 28, 2022): 207. http://dx.doi.org/10.18311/jmmf/2021/30104.
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In this article, high temperature oxidation behaviour of plasma sprayed carbides and oxides reinforced composite CoCrAlY coatings were investigated at 700°C. CoCrAlY was reinforced with Al<sub>2</sub>O<sub>3</sub>+YSZ, CeO<sub>2</sub>, WC-Co, Cr<sub>3</sub>C<sub>2</sub>-NiCr individually to produce four different coatings. SEM, EDS and XRD are used to analyze the oxide scales formed during oxidation process on the coatings surface. From the results it is found that, all these coatings exhibited parabolic weight gain nature, indicating presence of protective oxide scale on coating surface, whereas changes in total weight gain is observed. CoCrAlY+Al<sub>2</sub>O<sub>3</sub>+YSZ coatings exhibited higher oxidation resistance than other coatings. The distribution of thermodynamically stable á- Al<sub>2</sub>O<sub>3</sub> in the coating is shown slow-scale growth kinetics during the oxidation.
Дисертації з теми "Sub-surface profile"
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Gordon, Michael Oliver. "Non-destructive investigation of surface and sub-surface road pavement profiles." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/13938.
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Zheng, Yan Zong, and 鄭燕宗. "Depth profiles with sub-picometer resolution of the interfacial strains of Si0.7Ge0.3/Si using three-beam Bragg-surface diffraction." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/48080323156946303299.
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博士國立清華大學
物理系
104
For nano-semiconductor devices, how to enhance the device performance is one of the main goals of the semiconductor industries. As many devices are composed of thin-film systems in nano-scale, the carrier mobility would be directly governed by the strain of the thin film systems. The phenomenon could be applied to the strain-engineering [1-4] processes, which use the strain to improve the device performance and yet broaden their application [6]. Consequently, the strain is one of the important factors to the performeance of the device. However, the conventional methods of the strain measurement, transmission electron microscopy, TEM [7, 8], coherent X-ray diffraction image, CDI [9-13] and grazing incident X-ray diffraction, GIXD, are limited by destructive probing nature, the price of the instrument and the penetration depth, respectively. To dimension such a minor strain in strain-engineering processes, the depth profile with the sub-pico resolution of the interfacial strains are proposed by using three-beam Bragg-surface diffraction (BSD) [14, 15]. BSD is consisted of a symmetric Bragg diffraction at a wide-angle incidence and a surface diffraction, propagating along the interface of the sample. The three BSD, (004)/(202), (004)/ (0-22), (004)/ (4-22) were measured in this study. Moreover, we applied the hetero structure, Si0.7Ge0.3/Si, which are frequently used as semiconductor devices, to develop the technology of mapping the strain vs. depth with a sub-picometer resolution. Due to the structural proximity of the Si0.7Ge0.3 film and Si substrate, the surface diffraction of Si0.7Ge0.3 thin-film and Si substrate are simultaneously excited during the diffractive processes. Kiessig-like fringes are shown up in the vertical spatial intensity distributions (tth-scan). For mapping the stain in depth perpendicular to the hetero-junction, the spatial intensity were simulated by multi-layer dynamical theory [16-19] of X-ray diffraction for crystalline materials. Furthermore, the diffraction method reported in this dissertation may push the resolution of the current strain measurements from a dozen of nanometers to sub-pico meters regime in the future.
Частини книг з теми "Sub-surface profile"
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"Potential of Bio-Inspiration in 3- and 4-D Printing." In Inspiration and Design for Bio-Inspired Surfaces in Tribology, 294–347. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-1647-8.ch009.
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This chapter explores the potential of bio-inspiration in 3- and 4-D printing. The authors argue that the true potential of texturing hasn't been realized yet not because of the lack of enabling texturing technologies but because of the severe lack of detailed information about the functional details of texturing in a tribological situation, that is, how surface features, their geometry, interact with the functional gradients present within the subsurface layers to control the friction profile of a structure. The material emphasizes the potential of bio-inspired surfaces in providing a pathway for realizing true synchronization of function through a layer-by-layer customization of surface and subsurface material. In particular the chapter discusses methodologies to extract design parameters that lead to manifesting 4-D printed tribological constructs where surface and sub-surfaces respond optimally to external stimulants represented by the operation conditions of load, speed, and ambient temperature. Successful design of functional deterministic surfaces is not a product of mere biomimicry. Rather, it culminates probing the geometry, texture, form, and construction of the bio-analogue and linking these ingredients to the desired functional profile of the surface in the human engineering domain, that is, generation of bio-inspired functional surface designs stems from implementing design rules rather than replication of natural constructions. Deduction of design rules requires decoding the metrological features and the analysis of surface performance, of bio-analogues using standardized engineering methods. Success in designing a bio-inspired surface, therefore, requires a trans-disciplinary approach that combines engineering, physics, and biology. These don't combine naturally since they entail different methodologies of problem solving and investigations. It is hoped that this book would bridge the gap between the disciplines in the context of biomimetic surface design and construction. Further, it is hoped that the material would equip the reader with the basic skills needed to navigate between the biological and the engineering domains.
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Nseka, Denis, Vincent Kakembio, Frank Mugagga, Henry Semakula, Hosea Opedes, Hannington Wasswa, and Patience Ayesiga. "Implications of Soil Properties on Landslide Occurrence in Kigezi Highlands of South Western Uganda." In Landslides. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.99865.
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Generally, soil characteristics have a significant influence on landslide occurrence. This issue has, however, not yet been adequately analysed in Kigezi highlands of South Western Uganda. In this study, soil properties such as dispersion, grain size distribution, Atterberg limits, shear strength and clay mineralogy were analysed to establish their contribution to the spatial distribution of landslides in Kigezi highlands. The results demonstrate that deep soil profiles ranging between 2.5 and 7 meters were dominated by clay-pans at a depth between 0.75 and 3 meters. Although the uppermost surface horizons of the soil profile are loamy sand, the clay content is more than 35% especially in the sub soil. This suggests that the soil materials are Vertic in nature. In addition, the upper soil layers predominantly contain quartz, while subsurface horizons have considerable amounts of illite as the dominant clay minerals, ranging from 43–47%. The average liquid limit and plasticity index was 58.43% and 33.3% respectively. Besides, high average computed weighted plasticity index (28.4%) and expansiveness (38.6%) were obtained. These soil characteristics have great implication on the timing and nature of landslide processes in the study area. A change in soil material due to varying moisture content is thought to be a major trigger of landslides in Kigezi highlands of South Western Uganda. This understanding of soil characteristics is a key step in mitigating landslide hazards in the area.
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Shunmugavel, Manikandakumar, Ashwin Polishetty, Moshe Goldberg, Rajkumar Prasad Singh, and Guy Littlefair. "Tool Wear and Surface Integrity Analysis of Machined Heat Treated Selective Laser Melted Ti-6Al-4V." In 3D Printing, 228–40. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1677-4.ch012.
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In this study, the tool wear and surface integrity during machining of wrought and Selective Laser Melted (SLM) titanium alloy (after heat treatment) are studied. Face turning trails were carried out on both the materials at different cutting speeds of 60,120 and 180 m/min. Cutting tools and machined specimens collected are characterized using scanning electron microscope, surface profiler and optical microscope to study the tool wear, machined surface quality and machining induced microstructural alterations. It was found that high cutting speeds lead to rapid tool wear during machining of SLM Ti-6Al-4V materials. Rapid tool wear observed at high cutting speeds in machining SLM Ti-6Al-4V resulted in damaging the surface integrity by 1) Deposition of chip/work material on the machined surface giving rise to higher surface roughness and 2) Increasing the depth of plastic deformation on the machined sub surface.
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Gupta, H. K., G. S. Mittal, S. K. Verma, D. V. Divakaria Rao, M. S. Joshi, R. L. Dhar, S. C. Jain, et al. "Integrated G3 Investigations in Antarctica." In Geoscientific Investigations From the Indian Antarctic Program, 97–120. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-4078-0.ch005.
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CSIR-NGRI has been carrying out integrated G3 investigations in Antarctica since the second IAE. The geophysical studies of the initial 25 years of IAE included surface and helicopter-borne magnetic, EM, seismic, gravity, and paleomagnetic surveys. A total of 60 line-km magnetic profiles over the ice-shelf revealed the magnetic characteristics of the bedrock beneath the ice cover. Based on these and in conjunction with the early seismic studies, a crustal structural model was evolved. Secondary sulfide mineralisation near a suspected fissure zone in Schirmacher Oasis (SO) was inferred. It was based on the multi-frequency EM and radiometric measurements. The helicopter-borne magnetic N-S profiles over an area of 100x100sq.km with a spacing of about 3.0 km between SO and Wohlthat Mountains (WM) yielded gross features of sub-glacial topography nunataks (exposed peaks of sub-glacial hills).
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Pinchuk, Nataliia. "COMPARATIVE ANALYSIS OF STRUCTURE FORMATION AND PROPERTIES OF PVD COATINGS TIN, TI/TIN AND TIN-MON." In The scientific paradigm in the context of technological development and social change. Publishing House “Baltija Publishing”, 2023. http://dx.doi.org/10.30525/978-9934-26-297-5-19.
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Nanocomposite coatings represent a new generation of mate-rials and they consist of at least two phases with a nanocrystalline and/or amorphous structure. They have a lot of unique properties, the appear-ance of which is associated with a high volume fraction of phase boundar-ies, with the strength of these boundaries, with the absence of dislocations inside crystals. The purpose of the paper analysis of the reasons for the observed changes, based on the mechanism of formation of surface lay-ers of vacuum-arc coatings under the condition of implantation processes stimulated by applying a negative potential to the substrate. Methodology. All samples were obtained using modern coating methods on a modernized "Bulat-6" installation. Cross section imagines were carried out by meth-ods of optical, electron microscopy. Structure of the samples was studied using a "DRON-3M" instrument in Cu-Kα radiation. Separation of diffrac-tion profiles was carried out using the "New profile". Mechanical tests of materials were performed in the mode of microindentation. Results. At all schemes of deposition of TiN coatings, a single-phase state with an fcc lattice is formed. As the displacement potential increases, a transition from [100] to [111] texture is observed. In multilayer nanostructured TiN/Ti coat-ings, a texture develops in titanium nitride layers with a thickness of 300 nm or more when a displacement potential is applied [111]. The thickness of the Ti layers of more than 30 nm is sufficient for the development of the stress-strain state in the TiN layers without their significant relaxation. When the displacement potential increases, the macrostress of the compression in the titanium nitride layers of TiN increases. It was established that epitaxial growth of isostructural cubic modifications of titanium nitride and molybdenum nitride without the formation of a two-phase state is possible with a small thickness of layers in the TiN-Mo2N multilayer system (≈2 nm). At a greater thickness, a two-phase material is formed, where the second phase is high-temperature molybdenum nitride γ-Mo2N with a cubic lattice, which is isostructural to titanium nitride. Practical implications. The final properties of nanocrystalline coatings such as the size and orientation of the grains, the structure strongly depend on the technological parameters of deposition – ion bombardment, shear potential, temperature of the sub-strate, flow density and energy of the precipitating ions, therefore, in order to achieve the desired results in each specific case, it is necessary to strive for optimization of the process deposition of coatings. Value/originality. A possible mechanism for the formation of micro- and nanostructured lay-ered condensates under conditions of continuous influence of condensation of accelerated particles of the deposited flow is proposed. At the same time, the surface is subject to bombardment, which is based on radiation-stim-ulated processes of redistribution of elements of the deposited flow and structural defects of the coating material that is formed.
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"Benthic Habitats and the Effects of Fishing." In Benthic Habitats and the Effects of Fishing, edited by C. WILSON, H. ROBERTS, Y. ALLEN, and J. SUPAN. American Fisheries Society, 2005. http://dx.doi.org/10.47886/9781888569605.ch35.
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Coastal Louisiana, like many deltaic land masses, faces continued landscape alteration from natural processes and anthropogenic impacts that affect estuarine habitat. The most promising steps to slow/ mitigate these changes are river diversions that introduce freshwater and sediment to river-flanking environments and to help establish ideal salinities over historic oyster grounds. Critical to the success of these programs is a rapid and accurate means to qualify and quantify changes in oyster habitat. Digital high-resolution acoustic instrumentation linked to modern data acquisition and processing software was used to build baseline of information for evaluating future changes in shallow water bottoms, with special emphasis on oyster habitats. Application of digital side-scan sonar (100 and 500 kHz), a broad-spectrum sub-bottom profiler (4-24 kHz) for rapidly acquiring water column, surficial and shallow subsurface was used to map over 10,000 ha of water bottom. Geo-referenced side scan sonar mosaics were incorporated into a GIS data base. These data sets, “calibrated” with surface sampling, coring, and other “ground truthing” have established that numerically indexed acoustic reflectance intensities correlate closely with surface shell and oyster reef density. With image processing techniques to analyze mosaic reflectance patterns, we estimated the percent and total acreage of several bottom types.
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Leontiev, Pavlo, Inna Torianyk, and Svitlana Kalinichenko. "PARAMETERS OF BLOOD AND ERYTHROCYTES AS MARKERS OF AGE OF OCCURRENCE OF HEMATOMAS IN LIVING PERSONS." In Modernization of research area: national prospects and European practices. Publishing House “Baltija Publishing”, 2022. http://dx.doi.org/10.30525/978-9934-26-221-0-15.
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The article deals with solution of the scientific-practical task of modern forensic medicine: substantiation for medicolegal assessment of prescription of formation of posttraumatic sub- and epidural haemorrhages in living persons. The purpose: to determine the age of hematoma in living persons by the parameters of functional changes in the blood system and erythrocyte hematopoiesis. Methodology of the study is based on general research methods of analysis of cytological results the haematological indices, which were the most available and effective ones in accelerated diagnosis of the prescription of appearance of posttrtaumatic sub- and epidural haemorrhages, were studied by means of including methods of examination of aggregate properties of blood cells (superficial cytoarchitectonics of erythrocytes) and coagulation haemostasis parameters (fibrinogen, prothrombin, thrombocytes) into the methodological scheme. Results. In victims with epi- and subdural hematomas, changes in blood parameters (hemoglobin, erythrocytes, platelets, prothrombin, fibrinogen) were phase in nature. Against the background of stable control group figures, the number of erythrocytes decreased from the 1st to the 6th day with further rise (12th – 21st days of observations) and stabilization for 90 days. The increase in hemoglobin occurred from the 1st day of observation to the 21st day and ended with a digital plateau on the 90th day of the study. The parameters of coagulation hemostasis (fibrinogen, prothrombin) had similar digital profiles with outbreaks of rises on the 1st day of observation and a decrease in indicators on the 6th and 12th days, respectively. The increase in platelet count was gradual until the 12th day of observation. The erythrocyte link of the blood reacted to the occurrence of epi- and subdural hematomas by the appearance of coordination phenomena and changes in the surface membrane of cells with the development (in the approximate and distant delayed periods – 3-21 days) of expressive dispersion of forms from ovals, spherocytes to echino-. Gender-age dependence was not observed in the groups. Practical implications. The obtained data fully contribute to a reasonable solution of an important practical issue: determining the role of functional parameters of blood, its erythrocyte population in the development of unified programs / algorithms to determine diagnostic premortem markers of hematoma in the face of craniocerebral injuries. Value/originality lies in the possibility of applying the results of the work in modern diagnostic algorithms for the prescription of hematomas.
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Pomar, Luis, Juan Ignacio Baceta, and G. Mateu-Vicens. "The upper Miocene reef-rimmed platform of Mallorca (Spain): factory structure, growth dynamics and diagenesis." In Field guides to exceptionally exposed carbonate outcrops, 695–792. International Association of Sedimentologists, 2021. http://dx.doi.org/10.54780/iasfg3/13.
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The Llucmajor platform on southern Mallorca Island (Spain) is one of the best-exposed Miocene shallow-water carbonate platforms known in the world. Up to 90 m vertical sea cliffs provide a clean, continuous and detailed 3D view of the facies architecture and continuous cores from fifty-two water wells, affording information to interpret the 3D architecture of this 20 km-wide and only slightly deformed carbonate platform. Forty years of research on the Llucmajor platform provided insights into how the mutual interaction of biological and physical processes control the type of carbonate production and sediment dynamics which, along with changes in sea-level, determine the facies stacking patterns and the distribution of internal heterogeneities. Moreover, the ‘modern character’ of the carbonate-producing biota permits to capture the response of the carbonate system to changing ecological and oceanographic conditions. Although learnings from the Llucmajor platform do not apply to older platforms, it is this process-product type of analysis that can be applied to carbonate systems of all ages. Thus through this field guide, two carbonate factories working out of phase and with a non-linear response to sea-level changes are identified. A shallow-water euphotic (well lit) production (corals, red and green calcareous algae and associated heterozoan biota) predominated during rising sea-level when linear reefal rims grading to broad lagoons expanded and increased production and the sediment shed-off from these reef-lagoon systems built-out thick slopes. A deeper oligophotic (low light) factory expanded during the lowstands of sea-level when the light reached the basin floor; red algae, larger benthic foraminifers and molluscs were the prime producers. The Llucmajor platform grew up during the late Miocene, through the transition from greenhouse to icehouse climate that characterised the late Cenozoic. Its building blocks occur hierarchically stacked in response to the sea-level cyclicity. At the bed scale, the sigmoids consist of a lagoonal bed passing successively into sigmoidal reef core and then into slope clinobed and basinal deposits and bounded by an erosion surface onto the lagoon and reef and its correlative conformity basinward. Sigmoids stack in sets of sigmoids, these in cosets of sigmoids and these last in megasets, all of them fitting the characteristics of a depositional sequence when the genetic processes are analysed. Departures from the sequence model rely on the inter-dependence between depth gradient, the type of carbonate-producing biota and the ranges of sea-level cyclicity. Through the visit to a series of selected outcrops, this field guide offers a comprehensive assessment of the Llucmajor reef-rimmed shelf from the basin to the coral-dominated reefal margin and across the open-lagoon to restricted lagoon that defined the shelf top. The itinerary focusses on numerous topics and at different scales, from the study of discrete rock bodies to km-wide outcrop windows resembling high-resolution seismic profiles. The field guide integrates facies analysis, stratal architecture and distinct diagenetic features such as extensive secondary porosity after the dissolution of aragonitic components and pervasive dolomitization. Impressive sub-vertical collapse structures were produced by karstic dissolution during lowstands of sea-level and gravitational collapse of the roof complete the suite of diagenetic overprint. Altogether, the depositional and diagenetic attributes of the Llucmajor platform reveal a complex and highly heterogeneous carbonate system that is used as outcrop analogue for numerous Miocene carbonate reservoirs across the world.
Тези доповідей конференцій з теми "Sub-surface profile"
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Ahmad, Zeeshan, Abdullah Alhaj Al Hosini, Mohammed Ibrahim Al Janahi, Abdulla Mohammed Al Marzouqi, Muhammad Ali Siddiqui, Abdulla Haidar Abdulla Al Zarouni, and Reem Mohamad Alhamadi. "Integrity Challenges and Restoration of Sub-Surface Safety Valves by Innovative Rigless Techniques." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211192-ms.
Повний текст джерелаАнотація:
Abstract Sub-surface safety valves are the integral critical part of the well integrity management and their functionality cannot be compromised at any stage of well life. Unavailability of SSSV's due to integrity issues company was facing serious challenges in production and well availability during high gas demand. Moreover, workover solution led to 7-8 months for completion of workover and reinstatement of surface facilities. In this paper, case studies of different integrity related problems with sub-surface valves discussed and extensive study conducted to restore the critical sub-surface safety system. These case studies highlighted encountered problems such as landing nipple profile damaged due to corrosion/scale, movement of SSSV from its profile, broken flapper during hydraulic frac operation and conversion of TRSSSV to insert type with challenging well interventions issues. High pressure gas well was restored with redressed SSSV by using nipples gauge hanger above the valve to avoid any jumping of newly installed valve due to nipple profile washed out limitation. Insert type valve option evaluated for the same well with 40 MMSCF/D flow and concluded not suitable due to production constraints as ID of IVC was less than 2" which may be suitable for low producers. Special KMH tool designed and E-line utilized for real time monitoring during trouble shooting of TRSSV with broken flapper and successfully resumed the well accessibility for workover operation. Wireless technology can improve the accuracy of response and safety system of wells with limitation of relatively less flow specially in gas wells with scale challenges. Such approach may avoid the work over in case of more accurate control.
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Zhang, Xueping, Shenfeng Wu, and C. Richard Liu. "Hook Shaped Residual Stress: The Effect of Tool Ploughing, and the Analysis of the Mechanical and Thermal Effects." In ASME 2012 International Manufacturing Science and Engineering Conference collocated with the 40th North American Manufacturing Research Conference and in participation with the International Conference on Tribology Materials and Processing. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/msec2012-7220.
Повний текст джерелаАнотація:
To investigate the unique hook-shaped residual stress profile generated from hard turning process, an improved orthogonal (2-D) Finite Element (FE) model is established to include the ploughing effect of cutting edge. The model is further decomposed into two FE sub-models (sub-model 1 and sub-model 2) to determine the thermal and mechanical effects on the residual stress profiles by saw-tooth chip formation process and honed-edge ploughing process respectively. The two FE sub-models are sequentially adopted to evaluate the compression effect induced by chip formation process and ploughing effect resulted from honed-edge cutting tool on residual stress profile. Their separated and integrated effects on residual stress hook-shape profile are addressed by comparing the predicted residual stresses by sub-model 1, sub-model 2, the two sub-models’ superposition, and the whole improved FE model. The results show that chip formation effect on residual stress profile happens earlier than the ploughing effect. Chip formation effect provides a foundation for the finalized residual stress profile by determining the maximum depth and magnitude of the compressive residual stress. Ploughing process generates much more thermal load to produce the tensile residual stress in hard turned surface and sequentially drives the final resultant residual stress into an obvious hook-shaped by modifying the previous compressive residual stress profile. The location with the maximum compressive residual stress is identified as the critical position to separate the mechanical load and thermal load generated from ploughing effect. The decomposition methodology on mechanical and thermal effects is proposed and thoroughly discussed in the paper.
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Alcock, Simon G., Kawal J. S. Sawhney, and Stewart Scott. "Recent upgrades to the Diamond-NOM: A slope measuring profiler capable of characterizing the surface profile of large optics with sub-nanometer repeatability." In SPIE Optical Engineering + Applications, edited by Lahsen Assoufid, Peter Z. Takacs, and Anand K. Asundi. SPIE, 2010. http://dx.doi.org/10.1117/12.861623.
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Chen, Jiao, Yuan Li, Jianfeng Yu, and Wenbin Tang. "Profile Tolerances Modeling: A Unified Framework for Representing Geometric Variations for Line Profiles." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51154.
Повний текст джерелаАнотація:
Tolerance modeling is the most basic issue in Computer Aided Tolerancing (CAT). It will negatively influence the performance of subsequent activities such as tolerance analysis to a great extent if the resultant model cannot accurately represent variations in tolerance zone. According to ASME Y14.5M Standard [1], there is a class of profile tolerances for lines and surfaces which should also be interpreted correctly. Aim at this class of tolerances, the paper proposes a unified framework called DOFAS for representing them which composed of three parts: a basic DOF (Degrees of Freedom) model for interpreting geometric variations for profiles, an assessment method for filtering out and rejecting those profiles cannot be accurately represented and a split algorithm for splitting rejected profiles into sub profiles to make their variations interpretable. The scope of discussion in this paper is restricted to the line profiles; we will focus on the surface profiles in forthcoming papers. From the DOF model, two types of errors result from the rotations of the features are identified and formulized. One type of the errors is the result of the misalignment between profile boundary and tolerance zone boundary (noted as type 1); and if the feature itself exceeds the range of tolerance zone the other type of errors will form (noted as type 2). Specifically, it is required that the boundary points of the line profile should align with the corresponding boundary lines of the tolerance zone and an arbitrary point of the line profile should lie within the tolerance zone when line profile rotates in the tolerance zone. To make DOF model as accurate as possible, an assessment method and a split algorithm are developed to evaluate and eliminate these two type errors. It is clear that not all the line features carry the two type errors; as such the assessment method is used as a filter for checking and reserving such features that are consistent with the error conditions. In general, feature with simple geometry is error-free and selected by the filter whereas feature with complex geometry is rejected. According to the two type errors, two sub-procedures of the assessment process are introduced. The first one mathematically is a scheme of solving the maximum deviation of rotation trajectories of profile boundary, so as to neglect the type 1 error if it approaches to zero. The other one is to solve the maximum deviation of trajectories of all points of the feature: type 2 error can be ignored when the retrieved maximum deviation is not greater than prescribed threshold, so that the feature will always stay within the tolerance zone. For such features rejected by the filter which are inconsistent with the error conditions, the split algorithm, which is spread into the three cases of occurrence of type 1 error, occurrence of type 2 error and concurrence of two type errors, is developed to ease their errors. By utilizing and analyzing the geometric and kinematic properties of the feature, the split point is recognized and obtained accordingly. Two sub-features are retrieved from the split point and then substituted into the DOFAS framework recursively until all split features can be represented in desired resolution. The split algorithm is efficient and self-adapting lies in the fact that the rules applied can ensure high convergence rate and expected results. Finally, the implementation with two examples indicates that the DOFAS framework is capable of representing profile tolerances with enhanced accuracy thus supports the feasibility of the proposed approach.
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Zhang, Qiongyi, and Junhua Sun. "An adaptive fringe projection method for measuring three-dimensional profile of surface with high reflectivity using sub-pixel coordinate mapping." In Conference on Infrared Device and Infrared Technology, edited by Zelin Shi, HaiMei Gong, and Jin Lu. SPIE, 2021. http://dx.doi.org/10.1117/12.2606214.
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Hirasawa, Shigeki, Yoko Saito, Tatsuyuki Saito, and Hizuru Yamaguchi. "Flow Profile Simulation of Heated Copper Films on Substrates With Micro-Trenches." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0651.
Повний текст джерелаАнотація:
Abstract It is important that copper films fill the sub-micron trenches on silicon substrates in order to produce high-density electronic devices. In this paper, changes of the copper film profiles in trenches on silicon substrates during the reflow process were numerically calculated by 2- and 3-dimensional analyses. Calculation results from a model of atomic surface diffusion in a thin layer on the film were similar to experimental results. The relationship between the change of the film profile and the geometric parameters was determined. The results show that a uniform and thick initial film on the side walls of a trench is important to avoid film-bridge and void formation in the trench. In order to increase flow rate into the trenches, narrow trenches with a thick initial film on the bottom of the trench are effective.
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Hanna, Carl R., Steven Y. Liang, and Ru-Min Chao. "Specification of Shear Zone Characteristics in Achieving Desired Residual Stress Profile." In ASME 2007 International Manufacturing Science and Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/msec2007-31171.
Повний текст джерелаАнотація:
Surface integrity of a machined component in meeting the demands of a specific application requirement is defined by several characteristics. The residual stress profile at the surface and sub-surface of the workpiece is often one of these characteristics as it carries a direct effect on the fatigue life of a machined component. Machined residual stress is difficult to predict since it is governed by less than predictable high stresses, temperature gradients, and phase transformation occurring during the cutting process. A significant amount of effort have been dedicated by researchers to predict residual stress in a workpiece using analytical, experimental, and numerical modeling methods. Nonetheless, no method is available that could express the cutting process parameters and tool geometry parameters as functions of machined residual stress profile to allow process planning in achieving desired residual stress profile. This paper presents a physics-based approach to predict the shear zone characteristics during an orthogonal cutting operation. Using machined residual stress requirement at the surface as an input, information such as the shear angle, the shear stress in the shear zone, the depth of cut and consequently the cutting forces are obtained by inverse calculations procedure based on the rolling/sliding contact theory, the McDowell hybrid residual stress algorithm, and the specific cutting energy. This work constitutes a basis for further design and optimization of process and tool geometry parameters in achieving a specified residual stress profile. Experimental data are presented to validate the developed model.
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Antol, Stanislaw, Kunjin Ryu, and Tomonari Furukawa. "A New Approach for Measuring Terrain Profiles." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13136.
Повний текст джерелаАнотація:
This paper presents a new approach for measuring terrain profiles. The proposed approach uses RGB-D sensors to measure terrain surface relative to the vehicle. Since the RGB-D sensor is an area scanner, a feature matching technique called the grid-based feature-to-map matching technique, developed by the authors, matches objects seen in consecutive images and constructs a terrain profile in a global coordinate system. The RGB-D sensor are mounted inside a box to shield natural light and provide consistent LED lighting. As it constructs a terrain profile by matching scanned data regardless of the vehicle movement, the proposed approach is not affected by the vehicle movement as much as conventional techniques and achieves high accuracy. Preliminary experimental work indicates that the proposed approach could measure terrain profiles in sub-centimeter accuracy of all dimensions. The potential applicability of the proposed approach to the maintenance and inspection of railroads has also been demonstrated.
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Zherelyev, Alexandr, and Jon Bjorn Molster. "Influence of Temperature Profile Modelling on the Accuracy of Hydraulic Parameters Estimation Effect of Temperature Profile Change Due to Continuous Drillstring Rotation." In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22030-ea.
Повний текст джерелаАнотація:
Abstract ERD wells are widely used by operators in the MENA region to maximize reservoir contact, lower cost per barrel accessed, and to be able to access far away drill targets from fewer drill centers (wellhead platforms, islands, drill pads). ERD wells and associated required technological well construction approaches by nature are typically non-standard. ERD well construction require very exact and detailed engineering analysis and methodologies to be applied in order to develop suitable and accurate drilling designs that closely matches to the actual conditions. During drilling of ERD wells, a ME operator observed that the static geothermal gradient and subsequent modelling of dynamic flow temperature did not match actual downhole temperatures, hence modifications were required to the temperature profile to match the simulation of OBM drilling fluid ECD (Equivalent Circulating Density) to actual ECD measurements from the ECD pressure sub in the BHA. This temperature effect arises from the several factors, mainly in the sub-surface environment. The resulting mud temperature is significantly higher than static temperature and this has a high impact on mud rheology, resulting pressure losses and hole cleaning. Failure to model correctly can result in mud losses or loss of horizontal section because the ECD gets above formation fracture gradient, to low flowrates for effective hole cleaning due to excessive standpipe pressures, and other problems. This paper presents how hydraulics were modelled to match actual data (rheology, ECD, SPP, BHA, Flowrate, ROP, RPM etc) in one of the longest ERD wells ever drilled. In response to the challenges faced by a ME operator to improve the quality of hydraulic modelling and drilling design, a global Oil and Gas service company and a ME operator jointly explored the approaches for simulating Effective Temperature Profile on the giant offshore oil field, calibrated and verified it along hole with application for providing accurate estimation of hydraulic parameters. The workflow starts from analysis of actual temperature readings in upper sections of the well then uses it for simulating of Effective Temperature Profile in the reservoir section. Then simulated Effective Temperature Profile is imported to the simulation tool for proper drilling design.
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O’Donnell, Ryan, Tommy Powell, Mark Hoffman, and Zoran Filipi. "Inverse Analysis of In-Cylinder Gas-Wall Boundary Conditions: Investigation of a Yittria Stabilized Zirconia Thermal Barrier Coating for Homogeneous Charge Compression Ignition." In ASME 2016 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icef2016-9401.
Повний текст джерелаАнотація:
Thermal Barrier Coatings (TBC) applied to in-cylinder surfaces of a Low Temperature Combustion (LTC) engine provide opportunities for enhanced cycle efficiency via two mechanisms: (i) positive impact on thermodynamic cycle efficiency due to combustion/expansion heat loss reduction, and (ii) enhanced combustion efficiency. Heat released during combustion elevates TBC surface temperatures, directly impacting gas-wall heat transfer. Determining the magnitude and phasing of the associated TBC surface temperature swing is critical for correlating coating properties with the measured impact on combustion and efficiency. Although fast-response thermocouples provide a direct measurement of combustion chamber surface temperature in a metal engine, the temperature and heat flux profiles at the TBC-treated gas-wall boundary are difficult to measure directly. Thus, a technique is needed to process the signal measured at the sub-TBC sensor location and infer the corresponding TBC surface temperature profile. This task can be described as an Inverse Heat Conduction Problem (IHCP), and it cannot be solved using the conventional analytic/numeric techniques developed for ‘direct’ heat flux measurements. This paper proposes using an Inverse Heat Conduction solver based on the Sequential Function Specification Method (SFSM) to estimate heat flux and temperature profiles at the wall-gas boundary from measured sub-TBC temperature. The inverse solver is validated ex situ under HCCI like thermal conditions in a custom fabricated radiation chamber where fast-response thermocouples are exposed to a known heat pulse in a controlled environment. The analysis is extended in situ, to evaluate surface conditions in a single-cylinder, gasoline-fueled, HCCI engine. The resulting SFSM-based inverse analysis provides crank angle resolved TBC surface temperature profiles over a host of operational conditions. Such metrics may be correlated with TBC thermophysical properties to determine the impact(s) of material selection on engine performance, emissions, heat transfer, and efficiencies. These efforts will also guide next-generation TBC design.
Звіти організацій з теми "Sub-surface profile"
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Harris, L. B., P. Adiban, and E. Gloaguen. The role of enigmatic deep crustal and upper mantle structures on Au and magmatic Ni-Cu-PGE-Cr mineralization in the Superior Province. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328984.
Повний текст джерелаАнотація:
Aeromagnetic and ground gravity data for the Canadian Superior Province, filtered to extract long wavelength components and converted to pseudo-gravity, highlight deep, N-S trending regional-scale, rectilinear faults and margins to discrete, competent mafic or felsic granulite blocks (i.e. at high angles to most regional mapped structures and sub-province boundaries) with little to no surface expression that are spatially associated with lode ('orogenic') Au and Ni-Cu-PGE-Cr occurrences. Statistical and machine learning analysis of the Red Lake-Stormy Lake region in the W Superior Province confirms visual inspection for a greater correlation between Au deposits and these deep N-S structures than with mapped surface to upper crustal, generally E-W trending, faults and shear zones. Porphyry Au, Ni, Mo and U-Th showings are also located above these deep transverse faults. Several well defined concentric circular to elliptical structures identified in the Oxford Stull and Island Lake domains along the S boundary of the N Superior proto-craton, intersected by N- to NNW striking extensional fractures and/or faults that transect the W Superior Province, again with little to no direct surface or upper crustal expression, are spatially associated with magmatic Ni-Cu-PGE-Cr and related mineralization and Au occurrences. The McFaulds Lake greenstone belt, aka. 'Ring of Fire', constitutes only a small, crescent-shaped belt within one of these concentric features above which 2736-2733 Ma mafic-ultramafic intrusions bodies were intruded. The Big Trout Lake igneous complex that hosts Cr-Pt-Pd-Rh mineralization west of the Ring of Fire lies within a smaller concentrically ringed feature at depth and, near the Ontario-Manitoba border, the Lingman Lake Au deposit, numerous Au occurrences and minor Ni showings, are similarly located on concentric structures. Preliminary magnetotelluric (MT) interpretations suggest that these concentric structures appear to also have an expression in the subcontinental lithospheric mantle (SCLM) and that lithospheric mantle resistivity features trend N-S as well as E-W. With diameters between ca. 90 km to 185 km, elliptical structures are similar in size and internal geometry to coronae on Venus which geomorphological, radar, and gravity interpretations suggest formed above mantle upwellings. Emplacement of mafic-ultramafic bodies hosting Ni-Cr-PGE mineralization along these ringlike structures at their intersection with coeval deep transverse, ca. N-S faults (viz. phi structures), along with their location along the margin to the N Superior proto-craton, are consistent with secondary mantle upwellings portrayed in numerical models of a mantle plume beneath a craton with a deep lithospheric keel within a regional N-S compressional regime. Early, regional ca. N-S faults in the W Superior were reactivated as dilatational antithetic (secondary Riedel/R') sinistral shears during dextral transpression and as extensional fractures and/or normal faults during N-S shortening. The Kapuskasing structural zone or uplift likely represents Proterozoic reactivation of a similar deep transverse structure. Preservation of discrete faults in the deep crust beneath zones of distributed Neoarchean dextral transcurrent to transpressional shear zones in the present-day upper crust suggests a 'millefeuille' lithospheric strength profile, with competent SCLM, mid- to deep, and upper crustal layers. Mechanically strong deep crustal felsic and mafic granulite layers are attributed to dehydration and melt extraction. Intra-crustal decoupling along a ductile décollement in the W Superior led to the preservation of early-formed deep structures that acted as conduits for magma transport into the overlying crust and focussed hydrothermal fluid flow during regional deformation. Increase in the thickness of semi-brittle layers in the lower crust during regional metamorphism would result in an increase in fracturing and faulting in the lower crust, facilitating hydrothermal and carbonic fluid flow in pathways linking SCLM to the upper crust, a factor explaining the late timing for most orogenic Au. Results provide an important new dataset for regional prospectively mapping, especially with machine learning, and exploration targeting for Au and Ni-Cr-Cu-PGE mineralization. Results also furnish evidence for parautochthonous development of the S Superior Province during plume-related rifting and cannot be explained by conventional subduction and arc-accretion models.
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Wallach, Rony, Tammo Steenhuis, Ellen R. Graber, David DiCarlo, and Yves Parlange. Unstable Flow in Repellent and Sub-critically Repellent Soils: Theory and Management Implications. United States Department of Agriculture, November 2012. http://dx.doi.org/10.32747/2012.7592643.bard.
Повний текст джерелаАнотація:
Water repellency causes unstable wetting fronts that result in water moving in preferential flowpaths through homogeneous soils as well in structured soils where macropores enhance the preferential flow pattern. Water repellency is typically associated with extended water ponding on the soil surface, but we have found that repellency is important even before the water ponds. Preferential flow fingers can form under conditions where the contact angle is less than 90o, but greater than 0o. This means that even when the soil is considered wettable (i.e., immediate penetration of water), water distribution in the soil profile can be significantly non-uniform. Our work concentrated on various aspects of this subject, with an emphasis on visualizing water and colloid flow in soil, characterizing mathematically the important processes that affect water distribution, and defining the chemical components that are important for determining contact angle. Five papers have been published to date from this research, and there are a number of papers in various stages of preparation.
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Limoges, A., A. Normandeau, J. B R Eamer, N. Van Nieuwenhove, M. Atkinson, H. Sharpe, T. Audet, et al. 2022William-Kennedy expedition: Nunatsiavut Coastal Interaction Project (NCIP). Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/332085.
Повний текст джерелаАнотація:
The accelerating Arctic cryosphere decline severely impacts the land on which northern communities live through the presence of coastal and marine geohazards and coastal erosion, which further places the cultural heritage of coastal archaeological sites at risks. Sea ice decline also compromises the formation of polynyas, with unknown consequences for the regional ecosystems. From the 10th to the 18th of July 2022, a scientific cruise onboard the research vessel William-Kennedy allowed the collection of a suite of samples and data from the marine coastal environment of Nain, Nunatsiavut. In total, 42 surface sediment samples, 29 sediment cores, 41 conductivity-temperature-depth (CTD) profiles, 13 water samples, 24 phytoplankton nets and 13 zooplankton nets were collected. The cruise allowed the deployment of 2 moorings equipped with sediment traps in Nain Bay and within deeper offshore waters. Triangulation showed that the 2 moorings were correctly placed near their target locations. Drop camera transects were deployed in Webb Bay and at the easternmost tip of Paulmp;gt;'s Island to image the seabed and study benthic habitats. Finally, acoustic sub-bottom profiling along the entire study area allowed a high-resolution characterization of the stratigraphy of the seafloor, helped identifying locations for sediment sampling and inferring geological information about the depositional environments. The material and data collected during the research cruise will be key to 1) evaluating the productivity and dynamics of small recurring polynyas (i.e., rattles) on diverse timescales, 2) assessing marine and coastal geohazards (e.g., landslides) in relation to the deglacial history of Nain, 3) investigate the seabed geomorphology in Webb Bay and linkages with permafrost and sea-level changes and 3) conducting benthic habitat characterization. Co-led by the University of New Brunswick (UNB) and Natural Resources Canada (NRCan), this cruise was done in collaboration with the Government of Nunatsiavut, Université du Québec à Montréal, Université Laval, Dalhousie University and Memorial University, and was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and NRCan.