Thickness Distribution Pattern Research Articles

Optimizing the Thickness Uniformity of Magnetron Sputtering Deposited Films on a Large-Scale Curved Workpiece Surface

This study prepared magnetron-sputtering deposition film on a large-scale curved workpiece with a favorable thickness uniformity using a rectangular target cathode. For a substrate rotation structure with eccentric rotation/revolution composite motion, the geometrical model of the thickness distribution of the coating film on a large substrate was established in combination with the principle of rectangular cathode magnetron sputtering. The integral formula of the film thickness was derived, and various film thickness distribution patterns under different parameters were simulated. According to the present research results, the film thickness distribution can be optimized by adjusting the revolution-to-rotation radius and eccentric ratios. At an eccentric distance of 400 mm and a radius ratio of 2.78, the most favorable uniformity degree of 0.87 was obtained, which was controlled by the motion path of the fixed point on the substrate. The proposed approach helps to obtain large-scale films with favorable uniformity on the substrate.

Basin-wide unconventional potential of the Doig Formation, Triassic of the Western Canada Sedimentary Basin

The Doig Formation is a Lower to Middle Triassic fine-grained unit of the Western Canada Sedimentary Basin, which includes a phosphate-bearing basal unit informally defined as the Doig Phosphate Zone (DPZ). The DPZ is recognized as a significant source of hydrocarbons hosted in conventional reservoirs in the basin. Phosphatic mudstones are uncommon and studies of their source-rock potential are scarce. The regional distribution of the Doig Formation source-rock properties across its entire stratigraphic and spatial range is poorly understood. In this study, we characterize the source-rock potential of the Doig Formation through an integrated assessment of thickness, organic content, kerogen type and thermal maturity. A new method for estimating the relative contribution of kerogen type and its original hydrogen index pseudo-van Krevelen, is introduced. The method assumes a binary mixture of kerogen types and requires an assumption for the initial value of immature kerogen from each end-member. The Doig Formation thickens southwestwards from the eastern erosional edge towards the deformation front to a maximum thickness of 229 m. The upper Doig and DPZ have distinct thickness distribution patterns, which suggests a transition from a tectonically-influenced sedimentation marked by uplifting, faulting and erosion, to the start of physiographic healing and a return to large-scale subsidence. The source-rock generative potential of the Doig Formation is fair to good, containing kerogen Types II and III. The DPZ has higher total organic carbon (TOC) content, of up to 12.2% and a higher proportion of Type II kerogen than that the upper Doig, where the maximum TOC content is 8.4 wt%. Original TOC was higher in the northern part of the lateral extent, which is likely related to a connection with open ocean; and in a linear trend through the center of the basin, which represents the trough of a marine fore-arc basin. Thermal maturity increases to the southwest, from early oil to dry gas windows, in a trend that approximately correlates to gas wetness and liquid yield. A zone of dry gas occurs near the eastern edge, however, which may be explained by preferential updip migration of thermogenic methane generated at greater depths, or mixing of thermogenic and biogenic gas.

Study on Friction Characteristics of AA7075 Aluminum Alloy under Pulse Current-Assisted Hot Stamping

Friction during contact between metals can be very complex in pulse current-assisted forming. Based on stamping process characteristics, a reciprocating friction tester was designed to study the friction characteristics between AA7075 aluminum alloy and P20 steel under different current densities. Origin software was used to process the experimental data, and a current friction coefficient model was established for the pulse current densities. The results show that the friction coefficient of the aluminum alloy sheet decreased with the increase in the pulse current density (2–10 A/mm2). After that, the friction mechanism was determined by observing microscopic morphology and SEM: some oxide cracked on the friction surface when the current was large. Finally, finite element simulations with Abaqus software and a cylindrical case validated the constant and current friction coefficient models. The thickness distribution patterns of the fixed friction coefficient and the current coefficient model were compared with an actual cylindrical drawing part. The results indicate that the new current friction model had a better fit than the fixed one. The simulation results are consistent with the actual verification results. The maximum thinning was at the corner of the stamping die, which improved the simulation accuracy by 7.31%. This indicates the effectiveness of the pulse current friction model.

Hybrid digital twin for conditional lubricant oil transport simulation and oil consumption prediction in internal combustion engines

Reducing lubricant oil consumption (LOC) has long been an interest to engine manufacturers in an effort to reduce overall emissions from internal combustion (IC) engines. However, directly correlating engine operating conditions with LOC rates is a challenging task given its complex and multi-physics nature. Building on previous experimental observations and modeling efforts, a baseline hybrid model, which combines traditional physics-based numerical simulation with modern machine learning techniques, was developed. As the first step, the model is to compute the oil exiting the top ring gap with given oil supply rate and locations to the second land. Studies performed using the model reveal a strong dependency of LOC on engine speed, load as well as the relative locations of piston ring gaps. In particular, the close proximity of the oil source on second land to the top ring gap and the reverse gas flow at low load conditions can both induce high LOC. Piston ring gap rotations and the different oil supply mechanisms to the piston ring pack are also found to heavily influence the oil consumption behavior and oil film thickness distribution pattern. The present work is the first step to a more comprehensive model for predicting LOC for healthy systems of piston ring packs. The efficiency of the model made it possible to study the oil redistribution that takes many engine cycles to reach equilibrium and rotation of the ring gaps that could happen in reality at a time scale of minutes and even longer.

How does bone microanatomy and musculature covary? An investigation in the forelimb of two species of martens (Martes foina, Martes martes).

The long bones and associated musculature play a prominent role in the support and movement of the body and are expected to reflect the associated mechanical demands. But in addition to the functional response to adaptive changes, the conjoined effects of phylogenetic, structural and developmental constraints also shape the animal's body. In order to minimise the effect of the aforementioned constraints and to reveal the biomechanical adaptations in the musculoskeletal system to locomotor mode, we here study the forelimb of two closely related martens: the arboreal pine marten (Martes martes) and the more terrestrial stone marten (Martes foina), focusing on their forelimb muscle anatomy and long bone microanatomy; and, especially, on their covariation. To do so, we quantified muscle data and bone microanatomical parameters and created 3D and 2D maps of the cortical thickness distribution for the three long bones of the forelimb. We then analysed the covariation of muscle and bone data, both qualitatively and quantitatively. Our results reveal that species-specific muscular adaptations are not clearly reflected in the microanatomy of the bones. Yet, we observe a global thickening of the bone cortex in the radius and ulna of the more arboreal pine marten, as well a stronger flexor muscle inserting on its elbow. We attribute these differences to variation in their locomotor modes. Analyses of our 2D maps revealed a shift of cortical thickness distribution pattern linked to ontogeny, rather than species-specific patterns. We found that although intraspecific variation is not negligible, species distinction was possible when taking muscular and bone microanatomical data into consideration. Results of our covariation analyses suggest that the muscle-bone correlation is linked to ontogeny rather than to muscular strength at zones of insertion. Indeed, if we find a correlation between cortical thickness distribution and the strength of some muscles in the humerus, that is not the case for the others and in the radius and ulna. Cortical thickness distribution appears rather linked to bone contact zones and ligament insertions in the radius and ulna, and to some extent in the humerus. We conclude that inference on muscle from bone microanatomy is possible only for certain muscles in the humerus.

Distribution Pattern of Total Corneal Thickness in Keratoconus versus Normal Eyes Using an Optical Coherence Tomography.

Purpose:To evaluate the total corneal thickness distribution pattern using a high-resolution spectral-domain optical coherence tomography (HR SD-OCT) for distinguishing normal eyes from keratoconus (KCN).Methods:One hundred and forty-four patients were enrolled in three groups (55 normal, 45 mild KCN, and 44 moderate-to-severe KCN eyes) in this prospective diagnostic test study. Total corneal thickness was measured in 8 semi-meridians using HR SD-OCT (Heidelberg Engineering, Heidelberg, Germany) in 5 and 7 mm zones. The central corneal thickness (CCT), corneal focal thinning (minimum thickness [Min], min minus median and maximum [Min-Med, Min-Max]), and asymmetry indices (inferior minus superior [I-S] and supranasal minus infratemporal [SN-IT]) were calculated. One-way analysis of variance and the area under the receiver operating characteristic curve (AUC) were used for the analysis.Results:Thinner CCT, lower Min thickness, more negative Min-Max, Min-Med, and greater I-S and SN-IT were found in KCN eyes compared to the control group (P < 0.001). The inferior and IT semi-meridians were the thinnest locations in KCN cases in the 5 mm central zone (P < 0.001). CCT followed by Min-Med had the highest discriminative ability for differentiating mild KCN (AUC, sensitivity and specificity: 0.822, 87.0%, 60.37% and 0.805, 82.93%, 66.0%, respectively) and moderate-to-severe KCN (0.902, 87.82%, 73.08% and 0.892, 85.37%, and 78.85%, respectively) from normal corneas.Conclusion:The inferior and IT sectors of the cornea with the largest thickness changes in the 5 mm zone are the most common thinning sites in keratoconic corneas, and CCT and Min-Med are the most sensitive indices for the diagnosis of KCN.

Premolar enamel thickness and distribution of a Miocene hominid Lufengpithecus hudienensis compared with Pleistocene and extant hominids

Lufengpithecus hudienensis is a Late-Miocene hominid from the Yuanmou basin of southwestern China. Previous studies link Lufengpithecus to either the Sivapithecus-orangutan clade or a derived branch from the basal stem of the Hominidae. Despite a rich fossil assemblage, the taxonomy of L. hudienensis and its phylogenetic relationship with other hominids is still unclear. Enamel thickness in fossil and modern hominids can provide insights into taxonomy, phylogeny, and dietary reconstructions. In this study, 24 upper and lower L. hudienensis premolars were imaged using high-resolution microcomputed tomography. Three-dimensional average enamel thickness and relative enamel thickness (RET) indices, as well as whole-crown enamel distribution patterns were recorded for the L. hudienensis specimens and compared with a total of 113 specimens of fossil and extant apes and recent modern humans (RMH): fossil Pongo (n = 36), Gigantopithecus blacki (n = 21), Pan troglodytes (n = 11), Gorilla gorilla (n = 7), and RMH (n = 38). RET of the premolars of L. hudienensis was found to be similar to that of fossil Pongo, P. troglodytes, and G. gorilla, but less than Gi. blacki and RMH values. The distribution of enamel thickness shows a taxon-specific pattern for L. hudienensis, generally characterized by thicker enamel on the lateral wall than on the cusp apex, on the lingual cusp of the upper and buccal cusp of the lower premolars, with some differences with respect to fossil Pongo, Gi. blacki, P. troglodytes, and G. gorilla patterns. Additional characterizations of enamel thickness distribution patterns of the molars and other dental endostructural morphologies are needed to further explore the phylogenetic relationships of L. hudienensis with other hominids.

Characterization of surface oil thickness distribution patterns observed during the Deepwater Horizon (MC-252) oil spill with aerial and satellite remote sensing

Knowledge of the spatial distribution of oil thickness patterns within an on-water spill is of obvious importance for immediate spill response activities as well as for subsequent evaluation of the spill impacts. For long-lasting continuous spills like the 2010 3-month Deepwater Horizon (DWH) event in the Gulf of Mexico, it is also important to identify changes in the dominant oil features through time. This study utilized very high resolution (≤5m) aerial and satellite imagery acquired during the DWH spill to evaluate the shape, size and thickness of surface oil features that dominated the DWH slick. Results indicate that outside of the immediate spill source region, oil distributions did not encompass a broad, varied range of thicknesses. Instead, the oil separated into four primary, distinct characterizations: 1) invisible surface films detectable only with Synthetic Aperture Radar imaging because of the decreased surface backscatter, 2) thicker sheen & rainbow areas (<0.005mm), 3) large regional areas of relatively thin, “metallic appearance” films (0.005–0.08mm), and 4) strands of thick, emulsified oil (>1mm) that were consistently hundreds of meters long but most commonly only 10–50m wide. Where present within the slick footprint, each of the three distinct visible oil thickness classes maintained its shape characteristics both spatially (at different distances from the source and in different portions of the slick), and temporally (from mid-May through July 2010). The region over the source site tended to contain a more continuous range of oil thicknesses, however, our results indicate that the continuous injection of subsurface dispersants starting in late May significantly altered (lowered) that range. In addition to characterizing the oil thickness distribution patterns through the timeline of one of the world's largest oil spills, this paper also details the extension of using high resolution aerial imagery to calibrate medium resolution satellite data sources such as USA's Thematic Mapper (30m) to provide larger-scale spatial views of major spills, and discusses implications for utilizing such data for oil spill characterizations and spill response.

Sea ice thickness analyses for the Bohai Sea using MODIS thermal infrared imagery

Level ice thickness distribution pattern in the Bohai Sea in the winter of 2009–2010 was investigated in this paper using MODIS night-time thermal infrared imagery. The cloud cover in the imagery was masked out manually. Level ice thickness was calculated using MODIS ice surface temperature and an ice surface heat balance equation. Weather forcing data was from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses. The retrieved ice thickness agreed reasonable well with in situ observations from two off-shore oil platforms. The overall bias and the root mean square error of the MODIS ice thickness are–1.4 cm and 3.9 cm, respectively. The MODIS results under cold conditions (air temperature <–10°C) also agree with the estimated ice growth from Lebedev and Zubov models. The MODIS ice thickness is sensitive to the changes of the sea ice and air temperature, in particular when the sea ice is relatively thin. It is less sensitive to the wind speed. Our method is feasible for the Bohai Sea operational ice thickness analyses during cold freezing seasons.

Further morphological evidence on South African earliest Homo lower postcanine dentition: Enamel thickness and enamel dentine junction

The appearance of the earliest members of the genus Homo in South Africa represents a key event in human evolution. Although enamel thickness and enamel dentine junction (EDJ) morphology preserve important information about hominin systematics and dietary adaptation, these features have not been sufficiently studied with regard to early Homo. We used micro-CT to compare enamel thickness and EDJ morphology among the mandibular postcanine dentitions of South African early hominins (N = 30) and extant Homo sapiens (N = 26), with special reference to early members of the genus Homo. We found that South African early Homo shows a similar enamel thickness distribution pattern to modern humans, although three-dimensional average and relative enamel thicknesses do not distinguish australopiths, early Homo, and modern humans particularly well. Based on enamel thickness distributions, our study suggests that a dietary shift occurred between australopiths and the origin of the Homo lineage. We also observed that South African early Homo postcanine EDJ combined primitive traits seen in australopith molars with derived features observed in modern human premolars. Our results confirm that some dental morphological patterns in later Homo actually occurred early in the Homo lineage, and highlight the taxonomic value of premolar EDJ morphology in hominin species.

Crust‐scale 3D model of the Western Bredasdorp Basin (Southern South Africa): data‐based insights from combined isostatic and 3D gravity modelling

AbstractThe southern South African continental margin documents a complex margin system that has undergone both continental rifting and transform processes in a manner that its present‐day architecture and geodynamic evolution can only be better understood through the application of a multidisciplinary and multi‐scale geo‐modelling procedure. In this study, we focus on the proximal section of the larger Bredasdorp sub‐basin (the westernmost of the five southern South African offshore Mesozoic sub‐basins), which is hereto referred as the Western Bredasdorp Basin. Integration of 1200 km of 2D seismic‐reflection profiles, well‐logs and cores yields a consistent 3D structural model of the Upper Jurassic‐Cenozoic sedimentary megasequence comprising six stratigraphic layers that represent the syn‐rift to post‐rift successions with geometric information and lithology‐depth‐dependent properties (porosities and densities). We subsequently applied a combined approach based on Airy's isostatic concept and 3D gravity modelling to predict the depth to the crust‐mantle boundary (Moho) as well as the density structure of the deep crust. The best‐fit 3D model with the measured gravity field is only achievable by considering a heterogeneous deep crustal domain, consisting of an uppermost less dense prerift meta‐sedimentary layer [ρ = 2600 kg m−3] with a series of structural domains. To reproduce the observed density variations for the Upper Cenomanian–Cenozoic sequence, our model predicts a cumulative eroded thickness of ca. 800–1200 m of Tertiary sediments, which may be related to the Late Miocene margin uplift. Analyses of the key features of the first crust‐scale 3D model of the basin, ranging from thickness distribution pattern, Moho shallowing trend, sub‐crustal thinning to shallow and deep crustal extensional regimes, suggest that basin initiation is typical of a mantle involvement deep‐seated pull‐apart setting that is associated with the development of the Agulhas‐Falkland dextral shear zone, and that the system is not in isostatic equilibrium at present day due to a mass excess in the eastern domain of the basin that may be linked to a compensating rise of the asthenospheric mantle during crustal extension. Further corroborating the strike‐slip setting is the variations of sedimentation rates through time. The estimated syn‐rift sedimentation rates are three to four times higher than the post‐rift sedimentation, thereby indicating that a rather fast and short‐lived subsidence during the syn‐rift phase is succeeded by a significantly poor passive margin development in the post‐rift phase. Moreover, the derived lithospheric stretching factors [β = 1.5–1.75] for the main basin axis do not conform to the weak post‐rift subsidence. This therefore suggests that a differential thinning of the crust and the mantle‐lithosphere typical for strike‐slip basins, rather than the classical uniform stretching model, may be applicable to the Western Bredasdorp Basin.

Species recognition through wing interference patterns (WIPs) in Achrysocharoides Girault (Hymenoptera, Eulophidae) including two new species

Wing interference patterns (WIPs) are shown to be an important tool for species recognition in the genus Achrysocharoides Girault (Hymenoptera: Eulophidae). This is demonstrated by combining information from two previously published papers, comprising two cases of cryptic species, and by new material including the description of two new species, Achrysocharoides maieri and Achrysocharoides serotinae from North America. The cryptic species were initially separated through their distinct male WIPs. Subsequent analyses of the external morphology uncovered additional morphological differences supporting the original findings through WIPs, and biological data further strengthened the identity of these species. The new species described here also differ in their WIPs but the WIPs are similar in both sexes. Thus they provide a strong link between male and female and demonstrate that WIPs can also be useful for species recognition when the sexes are otherwise difficult to associate. Both new species are from Connecticut, USA, and were reared from Phyllonorycter propinquinella (Braun) (Lepidoptera: Gracillariidae) on black cherry (Prunus serotina); Achrysocharoides maieri has also been reared from Ph. nr crataegella on pin cherry (Prunus pensylvanica). To facilitate the identification of the new species they are included in a previously published key to North American species of Achrysocharoides. As a supplement to colourful WIPs we also demonstrate that grey scale images of uncoated wings from scanning electron microscopy can be used for visualization of the thickness distribution pattern in wing membranes.

The Lower Cretaceous chalk play in the Danish Central Trough

The Upper Hauterivian to Lower Albian strata of the Danish Central Trough comprise a varied succession of pelagic coccolith chalks, argillaceous chalks and marlstones with subordinate claystones. Where well developed, such as in the recently released North Jens-1 well, the reservoir-quality chalks form three distinct packets, separated by marlstone-dominated intervals. The latter include the dark, organic-rich markers, the Munk Marl Bed (Middle Barremian) and the Fischschiefer Member (Lower Aptian), which are widely recognized in NW Europe. The internal construction of the chalk play is also strongly influenced by unconformities, often of regional significance, which commonly define the boundaries of the individual chalk packets. Lateral variation in the stratigraphic development of these unconformities results in local truncation or absence of individual chalk units. Preliminary sequence stratigraphic analysis suggests that the stratigraphic development of the Lower Cretaceous chalk play in the Danish Central Trough resulted primarily from sea-level changes, although climatic changes during Barremian and Aptian times may have influenced carbonate production and siliciclastic supply. Gross thickness distribution patterns were controlled by local variation in subsidence and active inversion tectonism.

Regional Stratigraphic and Depositional Study of Rock Units in Upper Garden Gulch and Parachute Creek Members of Green River Formation, Piceance Creek Basin, Colorado: ABSTRACT

The Eocene Green River Formation in the Piceance Creek basin, Colorado, is well known for its thick sequence of rich oil shale and associated saline minerals. In the subsurface, rocks of economic interest extend from the upper part of the Garden Gulch Member to the top of the Parachute Creek Member. These rocks are lacustrine deposits that represent open-and near-shore sedimentation in ancient Lake Uinta. The depocenter of the lake formed in the northern part of the basin where rates of subsidence exceeded rates of sedimentation. The Garden Gulch and Parachute Creek Members can be divided into a series of laterally gradational rock units that can be traced from the eastern part of the Piceance Creek basin westward into the south-central part of the Uinta basin, Utah. Alon the margins of the Piceance Creek basin, the lower and middle units consist of fissile argillaceous shale of low organic content, silty claystone, and siltstone. Toward the depositional center of the basin, these rocks grade into a thick sequence of carbonate-rich, kerogenous shale and lean marlstone that is interbedded with a saline facies composed of nahcolite, dawsonite, and halite. The gradational boundary between these facies represents the contact between the Garden Gulch and Parachute Creek Members. In the subsurface, the contact can be recognized by a change from a low to high resistivity log response which reflects the transition from clay-rich to carbonate-rich rock. The regional thickness distribution pattern of individual units suggest that, during the middle Eocene, Lake Ui ta gradually expanded from a shallow, relatively fresh, semirestricted body of water to a saline, alkaline lake that occupied a closed basin. A pronounced thickening of the lowermost units along the southern margin of the basin is attributed to streams that prograded northward into the basin from the southern and southwestern margin of the lake. The middle and upper units, however, thin toward the basin edge, suggesting the lake gradually expanded to the south. During the late Eocene, open-lacustrine sedimentation shifted from the Piceance Creek basin westward into the Uinta basin, Utah, due to a large influx of siliciclastic sediment (Uinta Formation). Structural analysis of individual units indicates that present day intrabasinal tectonic features were not in existence during Parachute Creek time. End_of_Article - Last_Page 535------------

Preliminary Subsurface Study of Southeastern Appalachian Interior Plateau

Recent deep drilling in eastern Kentucky is adding much new subsurface information, making possible a reinterpretation of this portion of the Interior Plateau region. The present study is a preliminary report on the subsurface stratigraphy and structure of that region, including six newly made geologic cross sections and eight isopachous maps of various stratigraphic groups or series. Three matters in particular are reported. 1. There is a newly discovered Lower Cambrian coastal declivity which may be a fault scarp or a steep coastwise cliff that is responsible for an abrupt thickening of Early Cambrian deposits on its south-east side. Apparently it does not affect sediments of Dresbachian age. 2. As they appear to have quite different thickness-distribution patterns, rocks commonly called Mt. Simon-Eau Claire, or Lamotte-Bonneterre (the group known as Dresbachian) should be separated from overlying sediments and not regarded as Upper Cambrian. In this paper they are placed in the late Middle Cambrian. 3. There is a broad low concealed arch extending from north-central Ohio southward into eastern Kentucky, on top of which all Beekmantown strata have been removed by pre-Chazy erosion that also cut deeply into the Upper Cambrian below the Beekmantown. This arch, here named the Waverly Arch, lies about 60 miles east of the Cincinnati anticline which was apparently absent in pre-Trenton time. Many paleogeographic and structural relations hitherto assigned to the Cincinnati arch during pre-Trenton epochs are attributed now to the Waverly arch. If these and other preliminary observations are substantiated as is confidently expected, considerable revision is required of various subsurface interpretations previously held for this region.