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In order to study the reasonable range of flattening rate for shallow buried bias pressure small clear distance tunnels, based on the theory of surrounding rock deformation and numerical simulation, the stability of tunnel surrounding rock under different flattening rate conditions was analyzed. The value of flattening rate for small clear distance tunnels was discussed, and the rationality of the flattening rate range was verified by on-site monitoring data. Finally, the reasonable range of flattening rate for small clear distance tunnels was obtained. The results show that the flattening ratio of small clear distance tunnels has an impact on the distribution of plastic zone in surrounding rock, surface settlement, horizontal displacement of intermediate rock, arch settlement, and support shape variables. Based on the basic value of 0.432 flattening ratio, as the tunnel flattening ratio continues to increase, the stability of the surrounding rock of the entire tunnel continues to decrease, with 0.432 ~ 0.654 being the optimal flattening ratio range for the tunnel. The average error between the calculation results of the tunnel model and the on-site measured data is between 5% and 14%, which verifies the reliability of the numerical simulation and proves the credibility of the calculation method. Select the optimized tunnel section for construction and compare it with on-site monitoring data to verify the correctness of the optimized flatness ratio value. [ABSTRACT FROM AUTHOR]

This work aims to demonstrate the discrepancy between the results achieved in the application of ball-on-flat devices. Meanwhile, the interaction between contact parameters and the morphology of friction surfaces will be considered. Flattening depends on the mechanical properties of contact materials and the variation in the deformed structure in surface layers. To evaluate the interaction between roughness parameters and contact pressure, wear, and morphology of the surfaces, a ball-on-disk rig was applied. The average groove sizes were measured on micro- and macroscales. The relation between groove sizes on micro- and macro scales is close to the same. The flattening sinusoidal ball-on-flat model was considered. The real friction and wear tests were used to analyze plastic deformation by accounting for dislocation gliding and the interaction between neighboring asperities. The relation of shear stresses to the interference of rough asperities was established. The effective plastic strain gradient was evaluated. The formation of a highly effective plastic strain gradient is associated with a high dislocation density. The effect of dislocation density on the hardening–softening of surface layers is considered. [ABSTRACT FROM AUTHOR]

The Pereiro Massif (PM), located between the states of Ceará, Rio Grande do Norte and Paraíba, is a granitoid body that occupies an area of ​​approximately 2,200 km2, and and has maximum altitudes of 861 meters. This work aimed to elaborate and discuss the geomorphological compartmentalization of the Pereiro Massif and its surroundings. To this end, the following procedures were followed: 1) bibliographic and cartographic review on the geology and relief of the study area; 2) creation of the geomorphological map in a GIS environment, through SRTM image processing; 3) field activities for mapping conference, obtaining information to characterize the shapes and photographic survey. Fifteen units were mapped and grouped into three dimensions that consider the resulting processes and forms: accumulation, flattening and erosion surfaces. The compartments are classified recognizing processes associated with continental denudation with erosion, transport and deposition of material, based on structural geomorphology. The mapping carried out enhances the scientific notoriety of the PM and is expected to serve for environmental planning actions, such as the creation of protected areas and environmental licensing procedures.

Introduction: Significant corneal flattening and haze are important complications that can occur after combined corneal collagen cross-linking (CXL) and photorefractive keratectomy (PRK) procedures (CXL Plus). Case Presentation: We present a 24-year-old man who underwent combined standard CXL and PRK. The patient experienced satisfactory vision for approximately 4 years after the surgery. However, after this period, he began to complain of visual blurring. Subsequent examination revealed significant corneal haze, excessive flattening in both eyes, and thinning (thinnest point 227 μm in the right eye, 244 μm in the left eye) 4 years postoperatively. Upon presentation, the corrected distance visual acuity (CDVA) was 20/200 in the right eye and 20/400 in the left eye. The presenting refraction was +2.50 sph, −3.50 cyl *114 in the right eye and +11.5 sph, −9.75 cyl *81 in the left eye. With rigid gas permeable contact lenses, the corrected visual acuity was 20/50 in both eyes. Before the CXL Plus surgery, initial refraction and CDVA were 20/50 in the right eye (−5.50 sph, −3.00 cyl *175) and 20/30 in the left eye (−5.50 sph, −2.75 cyl *175). The patient was treated by penetrating keratoplasty. The CDVA reached 20/30 at the final follow-up. Conclusion: Our report highlights significant corneal haze and flattening that occurred 4 years after combined CXL and PRK treatment. These findings suggest that this procedure might not be safe in suspected patients of keratoconus. Further long-term follow-up research is necessary to evaluate the safety of combined CXL and PRK procedures.

Introduction: Significant corneal flattening and haze are important complications that can occur after combined corneal collagen cross-linking (CXL) and photorefractive keratectomy (PRK) procedures (CXL Plus). Case Presentation: We present a 24-year-old man who underwent combined standard CXL and PRK. The patient experienced satisfactory vision for approximately 4 years after the surgery. However, after this period, he began to complain of visual blurring. Subsequent examination revealed significant corneal haze, excessive flattening in both eyes, and thinning (thinnest point 227 μm in the right eye, 244 μm in the left eye) 4 years postoperatively. Upon presentation, the corrected distance visual acuity (CDVA) was 20/200 in the right eye and 20/400 in the left eye. The presenting refraction was +2.50 sph, −3.50 cyl *114 in the right eye and +11.5 sph, −9.75 cyl *81 in the left eye. With rigid gas permeable contact lenses, the corrected visual acuity was 20/50 in both eyes. Before the CXL Plus surgery, initial refraction and CDVA were 20/50 in the right eye (−5.50 sph, −3.00 cyl *175) and 20/30 in the left eye (−5.50 sph, −2.75 cyl *175). The patient was treated by penetrating keratoplasty. The CDVA reached 20/30 at the final follow-up. Conclusion: Our report highlights significant corneal haze and flattening that occurred 4 years after combined CXL and PRK treatment. These findings suggest that this procedure might not be safe in suspected patients of keratoconus. Further long-term follow-up research is necessary to evaluate the safety of combined CXL and PRK procedures. [ABSTRACT FROM AUTHOR]

The authors investigate the possibility of intensification of pipe bending by creating a minimum curvature considering the thin-wall profile, which is on the limit of exhausting the material’s bearing capacity (destruction). They consider an annular shell (pipe) under the action of pure bending moment, assuming the hypothesis of planar cross-sections and regarding the effect of T. Karman. The deformation changes of geometrical parameters (profile ovalization, wall thinning) are found. The compressive (radial) and tensile (tangential) deformations are calculated with account of their continuity based on the condition of volume constancy. In accordance with the accepted assumptions of mathematical modeling, the dependence of the radial stress on the edge of the bending segment, known from the theory of sheet stamping, is taken, where the most convenient criterion for plasticity is the hypothesis of the energy of shape change of the Mohr’s theory, characterized by the intensity of deformations in the bent section of the pipe, which determines the destruction of the material. The criterion of plasticity, specific mechanical properties of the material obtained in tensile tests (yield and strength limits, relative elongation) and approximated by a step dependence are used for making a combined estimation of the influence of geometric parameters (thinness, ovalization of the profile, deformation thinning of the wall) on the realization of bending of minimum curvature, characterized by loss of wall stability with subsequent failure due to exhaustion of the bearing capacity of the material possessing specific plasticity. Summarizing the results of the minimum (corrugation) and critical (destruction) bending radii, makes it possible to establish the ultimate degree of bending intensification.

This work aims to demonstrate the discrepancy between the results achieved in the application of ball-on-flat devices. Meanwhile, the interaction between contact parameters and the morphology of friction surfaces will be considered. Flattening depends on the mechanical properties of contact materials and the variation in the deformed structure in surface layers. To evaluate the interaction between roughness parameters and contact pressure, wear, and morphology of the surfaces, a ball-on-disk rig was applied. The average groove sizes were measured on micro- and macroscales. The relation between groove sizes on micro- and macro scales is close to the same. The flattening sinusoidal ball-on-flat model was considered. The real friction and wear tests were used to analyze plastic deformation by accounting for dislocation gliding and the interaction between neighboring asperities. The relation of shear stresses to the interference of rough asperities was established. The effective plastic strain gradient was evaluated. The formation of a highly effective plastic strain gradient is associated with a high dislocation density. The effect of dislocation density on the hardening–softening of surface layers is considered.

Eager equality for algebraic expressions over partial algebras distinguishes or separates terms only if both have defined values and they are different. We consider arithmetical algebras with division as a partial operator, called meadows, and focus on algebras of rational numbers. To study eager equality, we use common meadows, which are totalisations of partial meadows by means of absorptive elements. An axiomatisation of common meadows is the basis of an axiomatisation of eager equality as a predicate on a common meadow. Applied to the rational numbers, we prove completeness and decidability of the equational theory of eager equality. To situate eager equality theoretically, we consider two other partial equalities of increasing strictness: Kleene equality, which is equivalent to the native equality of common meadows, and one we call cautious equality. Our methods of analysis for eager equality are quite general, and so we apply them to these two other partial equalities; and, in addition to common meadows, we use three other kinds of algebra designed to totalise division. In summary, we are able to compare 13 forms of equality for the partial meadow of rational numbers. We focus on the decidability of the equational theories of these equalities. We show that for the four total algebras, eager and cautious equality are decidable. We also show that for others the Diophantine Problem over the rationals is one-one computably reducible to their equational theories. The Diophantine Problem for rationals is a longstanding open problem. Thus, eager equality has substantially less complex semantics. [ABSTRACT FROM AUTHOR]

Approximately half of global steel production is dedicated for manufacturing sheets. Due to global warming, geopolitical instabilities and rising raw material costs, recycling sheet metal is increasingly important. Conventional recycling has inefficiencies, therefore improving material efficiency and adopting circular economy strategies is necessary to halve CO2 emissions by 2050. This paper presents a review of sheet metal reuse techniques and introduces an innovative remanufacturing framework of curved steel sheet, with a special focus on the automotive sector and car-body panels. To support the framework presented, an experimental procedure on small-scale samples was carried out. The material tested was DC 0.4 steel parts (0.8 mm thick) characterized by different curvature radii. The material was reshaped and flattened under different conditions to understand the effect of the process variables onto the final quality of the remanufactured parts. The experiments showed that even parts with small curvatures can be flattened and reshaped with success. Lastly, to support the general remanufacturing framework presented, some flattening simulations of a large car-body are presented, revealing the importance of implementing a dwelling stage in the process and the advantage of performing such process with heated tools. [ABSTRACT FROM AUTHOR]

In this paper, the large deflection response of a circular mesh tube under pure bending was investigated by using FE analysis. In the previous study[Nakamura, T., Ushijima, K., Evaluation of large deflection response of circular mesh tubes, Transaction of the JSME (in Japanese), Vol. 88, No. 915 (2022)], the effect of the ovalization across the cross-section on the bending response was neglected, but in this study, the influence of cross-sectional flattening on the nonlinear bending moment versus curvature was taken into consideration. There are three reasons for arising the maximum bending moment, but in this paper, we mainly focused on the two mechanisms (the large flattening response in elastic deformation and the plastic yielding behaviour) to the maximum bending moment. Based on our FE analysis, we proposed theoretical equations for predicting the maximum bending moment as a function of tube geometries and material parameters such as Poisson’s ratio and the plastic yielding stress.

The hippocampus is one of the most studied neuroanatomical structures due to its involvement in attention, learning, and memory as well as its atrophy in ageing, neurological, and psychiatric diseases. Hippocampal shape changes, however, are complex and cannot be fully characterized by a single summary metric such as hippocampal volume as determined from MR images. In this work, we propose an automated, geometry-based approach for the unfolding, point-wise correspondence, and local analysis of hippocampal shape features such as thickness and curvature. Starting from an automated segmentation of hippocampal subfields, we create a 3D tetrahedral mesh model as well as a 3D intrinsic coordinate system of the hippocampal body. From this coordinate system, we derive local curvature and thickness estimates as well as a 2D sheet for hippocampal unfolding. We evaluate the performance of our algorithm with a series of experiments to quantify neurodegenerative changes in Mild Cognitive Impairment and Alzheimer’s disease dementia. We find that hippocampal thickness estimates detect known differences between clinical groups and can determine the location of these effects on the hippocampal sheet. Further, thickness estimates improve classification of clinical groups and cognitively unimpaired controls when added as an additional predictor. Comparable results are obtained with different datasets and segmentation algorithms. Taken together, we replicate canonical findings on hippocampal volume/shape changes in dementia, extend them by gaining insight into their spatial localization on the hippocampal sheet, and provide additional, complementary information beyond traditional measures. We provide a new set of sensitive processing and analysis tools for the analysis of hippocampal geometry that allows comparisons across studies without relying on image registration or requiring manual intervention.

Since the Moon is less flattened than the Earth, most lunar GIS applications use a spherical datum. However, with the renaissance of lunar missions, it seems worthwhile to define an ellipsoid of revolution that better fits the selenoid. The main long-term benefit of this might be to make the lunar adaptation of methods already implemented in terrestrial GNSS and gravimetry easier and somewhat more accurate. In our work, we used the GRGM 1200A Lunar Geoid (Goossens et al. in A global degree and order 1200 model of the lunar gravity field using GRAIL mission data. In: Lunar and planetary science conference, Houston, TX, Abstract #1484, 2016; Lemoine et al. in Geophys Res Lett 41:3382–3389. http://dx.doi.org/10.1002/2014GL060027, 2014), a 660th degree and order potential surface, developed in the frame of the GRAIL project. Samples were taken from the potential surface along a mesh that represents equal area pieces of the surface, using a Fibonacci sphere. We tried Fibonacci spheres with several numbers of points and also separately examined the effect of rotating the network for a given number of points on the estimated parameters. We estimated the best-fitting rotation ellipsoid's semi-major axis and flatness data by minimizing the selenoid undulation values at the network points, which were obtained for a = 1,737,576.6 m and f = 0.000305. This parameter pair is already obtained for a 10,000 point grid, while the case of reducing the points of the mesh to 3000 does not cause a deviation in the axis data of more than 10 cm. As expected, the absolute value of the selenoid undulations have decreased compared to the values taken with respect to the spherical basal surface, but significant extreme values still remained as well. [ABSTRACT FROM AUTHOR]

Analyzed here in the paper are the regularities of influences on the tensile test result by various factors, including sampling, specimen flattening and processing of the linepipe and the tensile ratio. And the control requirements for improving the data accuracy of the tensile test are presented. It is concluded via the analysis that in case of taking the sample from the steel pipe with flame cutting method, the length of the sample should be determined as per the OD and WT of the pipe, and the test sample should not be taken at a position under 50 mm; the overall length of the sample can be properly reduced by means of the on-line water-cooling process; compared with the room temperature strain aging, the strain aging with the temperature over 210 V, produces more obvious influence on the tensile property, while compared with the specimen flattening frequency, the unevenness of the plate tensile specimen produces much more influence on the yield strength. [ABSTRACT FROM AUTHOR]

A knotted surface in S 4 may be described by means of a hyperbolic diagram that captures the 0-section of a special Morse function, called a hyperbolic decomposition. We show that every hyperbolic decomposition of a knotted surface K defines a projection of K onto a 2-sphere Σ , whose set of critical values is the hyperbolic diagram of K . We apply such projections, called flattenings, to define three invariants of knotted surfaces: the layering, the trunk, and the partition number. The basic properties of flattenings and their derived invariants are obtained. Our construction is used to study flattenings of satellite 2-knots. [ABSTRACT FROM AUTHOR]

The algebraic properties of flattenings and subflattenings provide direct methods for identifying edges in the true phylogeny—and by extension the complete tree—using pattern counts from a sequence alignment. The relatively small number of possible internal edges among a set of taxa (compared to the number of binary trees) makes these methods attractive; however, more could be done to evaluate their effectiveness for inferring phylogenetic trees. This is the case particularly for subflattenings, and the work we present here makes progress in this area. We introduce software for constructing and evaluating subflattenings for splits, utilising a number of methods to make computing subflattenings more tractable. We then present the results of simulations we have performed in order to compare the effectiveness of subflattenings to that of flattenings in terms of split score distributions, and susceptibility to possible biases. We find that subflattenings perform similarly to flattenings in terms of the distribution of split scores on the trees we examined, but may be less affected by bias arising from both split size/balance and long branch attraction. These insights are useful for developing effective algorithms to utilise these tools for the purpose of inferring phylogenetic trees. [ABSTRACT FROM AUTHOR]

The load capacity of a preliminarily tightened bolt is analyzed as a function of the pliability of the components at contact (with deformation of the surface roughness) and also their relative hardness. [ABSTRACT FROM AUTHOR]

Introduction. The article presents the results of experimental and theoretical research of technological process of the PZ-1M grain flattener with a feeding device. The research was carried out at the Federal Agricultural Research Center of the North-East Named after N. V. Rudnitsky in 2011‒2019. The purpose of the research is to design a feeder scheme for the grain flattener, determine rational parameters of its working body (feed roller) and test the improved grain flattener. Materials and Methods. A constructive and technological scheme of the grain flattener with a feeding device is proposed, the novelty of which is confirmed by patents Nos. 2628297 and 2557780. The structural scheme of grain flattener with a feeding device comprising an active working body – a feeding roller with blades is developed. There was carried out theoretical research of the grain motion along the feeder roller blades to determine the patterns of grain motion depending on the values of the roller parameters. Results. It is established that with the size of the feed roller inner radius 0.045 m and more all the grain passes down from the roller blade into the feed channel and through it for flattening at the required exit angle of 60°, roller speed of not less than 400 min–1 and the value of the coefficient of the grain friction on the roller blade less than 0.4. When these parameters are observed, the feeding roller and the device are effective. Taking into account the results of researches, we have developed the design documentation and produced the PZ-1M grain flattener comprising a feeder. Departmental and comparative tests of the flattener were conducted, which showed high efficiency of its application: machine reliably and qualitatively performs the technological process of flattening grains. Discussion and Conclusion. The use of a power device in the design of the flattener increases the conditioning capacity by 2.08 times while reducing the energy intensity of the process by 1.6 times; the annual economic effect of using the PZ-1M grain flattener with feeding device compared to its analogue is 67,583 rub. at the level of intensification of 49%.

Bamboo is widely recognized as an engineering material with great potential. Conventional rectangular bamboo strip lumber has low utilization rate from milling arc-shaped strips flat and variable strength properties from natural bamboo’s hierarchical tissue structure. In this work an energy-efficient hydrothermal compression process to flatten and densify arc-shaped bamboo is presented. The green (70 % moisture content) bamboo strips were hot compressed in the radial direction at 3.0 MPa pressure, and at 170 °C or 190 °C heat for 20 min. After compression, arcs became rectangular with low (

A device is proposed for determining the pressure in a joint based on an interference fit. Its sensitive element consists of balls located between the contacting surfaces. Two types of contact interaction between the balls and the components of the joint are considered: elastoplastic deformation of the balls; and elastoplastic deformation of the parts. The pressure in shaft–bush contact is determined from the deformation. [ABSTRACT FROM AUTHOR]

Age and gender intersect, often lowering quality of life for older women. Microlevel patterns include ignoring older women in one's presence, flattening their identities to only their status as older women. Macrolevel patterns include the erasure of older women, with cultural (media) representations, organizational practices and policies and social policies that ignore the existence of older women or distort their characteristics in ways that diminish the likelihood of equitable treatment. Using autoethnography, conversations with a small group of older women, and scholarly and popular literature, we describe varieties of microlevel experiences and responses to them. Focusing on macrolevel erasure, we describe some of the effects of combined ageism and sexism, and we look at activists' and organizational responses aimed at changing public awareness and attitudes toward age and gendering. Policy changes are suggested to make the social treatment of older women more equitable, including attention to housing, health care, and public education. We note specific past achievements that demonstrate policy change is possible. [ABSTRACT FROM AUTHOR]

In this paper, we show that Loewner spaces introduced by Heinonen and Koskela (Acta Math., 1998) are preserved under quasimöbius mappings between Ahlfors regular spaces. [ABSTRACT FROM AUTHOR]

Bamboo, as a renewable biomass material, has received wide public attention. However, due to the thin-walled and hollow structure of bamboo, the mainstream processing method is complex and requires splitting the bamboo into narrow strips and then gluing them together for further manufacturing products. In addition, the surface glue residue makes the safety of indoor applications a concern, especially for cutting boards that come into contact with food. In response to the above problems, this paper introduces a bamboo flattening technology, which can flatten and unfold the pre-treated bamboo into a large-size flattened bamboo board (FBB). The results show that, compared to untreated bamboo, the dimensional stability of the FBB was improved and the flexural strength and elastic modulus of the FBB were increased by about 8.0%. The flattened bamboo cutting board was manufactured with the FBB as the surface layer and had a moisture content and hardness value of 9.2% and 5080 N, respectively, and the accumulated dip peel length of any glue layer was less than 25 mm. The flattened bamboo cutting board is proved to be a carbon-neutral product with a carbon footprint value of −42.92 kg CO2/t. This work provides a theoretical basis for the fabrication of large-size unspliced bamboo boards and provides new ideas for the scenario-specific application of FBBs. Using a FBB to make cutting boards can avoid contact between food and adhesives, making them more hygienic. The findings of this research can be used to make bamboo cutting boards more hygienic, environmentally friendly and possess excellent physical and mechanical properties.

The wheel–rail interaction during rolling along a straight railroad track section with and without the rail flattening effect is modeled. Rail flattening is used to describe a defect that occurs in the area of a welded rail joint. The model takes into account an increase in the load during dynamic impactless interaction in the region of welded joints, change in the configuration of the contact region, and existence of stick and slip subregions during rolling. The contact characteristics and stress states of the rail are compared for different relative longitudinal slip and in the presence and absence of track flattening of two characteristic sizes. An analysis of internal stresses shows that an increase in the relative longitudinal slip leads to an increase in the maximal tangential stresses near the surface. The results of analyzing contact pressures and tangential stresses show that, with an increase in the flattening depth, the depth wise distribution of maximal tangential stresses becomes more uniform. [ABSTRACT FROM AUTHOR]

In this paper real-time people detection is demonstrated in a relatively large indoor industrial robot cell as well as in an outdoor environment. Six depth sensors mounted at the ceiling are used to generate a merged point cloud of the cell. The merged point cloud is segmented into clusters and flattened into gray-scale 2D images in the xy and xz planes. These images are then used as input to a classifier based on convolutional neural networks (CNNs). The final output is the 3D position (x,y,z) and bounding box representing the human. The system is able to detect and track multiple humans in real-time, both indoors and outdoors. The positional accuracy of the proposed method has been verified against several ground truth positions, and was found to be within the point-cloud voxel-size used, i.e. 0.04m. Tests on outdoor datasets yielded a detection recall of 76.9 percent and an F1 score of 0.87.

Bamboo is an ideal engineering material for construction and furniture applications due to its rapid growth and exceptional mechanical properties. In recent years, bamboo flattening techniques have been extensively studied and applied. In this work, a straightforward and efficient method for flattening arc-shaped bamboo splits is proposed. Gradient pressure was used in the flattening process, increasing bamboo density by 12% – 15%. Also, the mechanical properties of the flattened bamboo splits exhibited significant enhancement. The maximum flexural strength and modulus of elasticity (MOE) values were achieved when flattened at 180°C. The modulus of rupture (MOR) and MOE of flattened bamboo were determined to be 212.04 MPa and 14.14 GPa, which are 57.19% and 35.53% higher than those of natural bamboo. Further, the outer surface of flattened bamboo exhibited hydrophobic characteristics, as evidenced by the contact angle exceeding 90°. The dimensional stability and water absorption of flattened bamboo splits were influenced by flattening temperature variations. Temperatures ≥180 °C resulted in excellent dimensional stability, with warpage levels below 2%. This process can improve the dimensional stability and mechanical properties of bamboo, and the flattened bamboo splits do not require further drying treatment, which positively affects bamboo processing and utilization. • Gradient pressure flattening enhanced the mechanical properties of the bamboo. • The complete preservation of the bamboo wall contributed to a higher utilization rate. • The bamboo flattening process was simplified, eliminating the need for additional drying. • Higher temperatures could increase the success rate of bamboo split flattening. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to investigate the invariant properties of uniform domains under flattening and sphericalization in nonlocally compact complete metric spaces. Moreover, we show that quasi-Möbius maps preserve uniform domains in nonlocally compact spaces as well. [ABSTRACT FROM AUTHOR]

The general theoretical properties and various approximate formulas for the angle χS of astronomical refraction at S are presented, beginning with its fundamental expression by the refraction integral and immediately leading to the Simpson formula. Assuming a spherically symmetric atmosphere, many additional results show up, starting with Oriani's "theorem" and Bouguer's equation. From these, an usual form of the refraction integral is derived. A fundamental approximation follows to deduce the Laplace formula, then the series expansions that generalize it but are divergent for an isothermal atmosphere--because of the approximation made. Two results, free from any approximation, exist and are presented: Biot's and Biot-Sang-Meyer-Fraser-White's theorems. It leads to an approximate link with extinction, as found by Laplace, and an approximation of the refraction χSh for points on the astronomical horizon. We compute the chromatic effects on χS, χSh--and (in a document associated with this article) on various characteristics of optical ducts considered in air--and an original expression of the "local vertical angular distortion coefficient" on the horizon (in Annexe B). [ABSTRACT FROM AUTHOR]

Two contrasting results of strain analyses, constriction and flattening, are recognized in the Sambagawa high‐pressure/temperature metamorphic belt, SW Japan. An unverified proposal to account for this situation is that the constrictional strain ellipsoids develop only in areas where there is strong overprinting by a secondary Du‐phase folding after a penetrative Ds‐phase deformation. Field studies in the Hibihara district, central Shikoku, which is located between a southern constrictional region and a northern flattening region, reveal there is a map‐scale contrast in the effect of Du: outcrop‐scale Du upright folds are common in the southern region while they are rare in the northern region. Field measurements show that overall orientation of Ds strain is characterized by E–W stretching and vertical shortening, while that of Du strain is characterized by N–S shortening and vertical extension. The shortening caused by Du in the southern high‐Du‐strain regions estimated by the fold‐curve tracing method are down to about 70%–56% and by removing this Du shortening most of the constrictional strain ellipsoids are restored back to the flattening field with only a few exceptions, suggesting that pre‐Du strain states of the Sambagawa metamorphic rocks were dominantly of the flattening type. These results support the previous ideas that invoke differences in the strength of Du overprinting for the two different types of strain ellipsoids observed in the Sambagawa belt. From a tectonic point of view, the semi‐penetrative occurrence of Du folds throughout the Sambagawa belt, which stretches about 800 km in SW Japan, suggests that the Du phase can be related to some ancient plate movement. The significant shortening subnormal to the orogen that characterizes Du may reflect a shift to orogen‐subnormal subduction of the Pacific plate beneath the Eurasian plate at around 60 Ma. [ABSTRACT FROM AUTHOR]

The paper considers the main aspects of designing a technology for the manufacture of seamless cold-deformed tubes made of 12Kh18N10T austenitic steel according to possible schematic diagrams of coiled tube production and actual technical solutions ensuring its rational organization under the conditions of domestic plants. A generalized method for determining the optimal drum diameter is presented along with features of calculating the main technological parameters, taking into account the actual nature of material hardening processes. An effective technology is proposed for the manufacture of coiled tubes under the operating conditions of TMK-INOX LLC, having an outer diameter of 10–25 mm, a wall thickness of 1.0–1.5 mm, and a length of at least 50 m. [ABSTRACT FROM AUTHOR]

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Following the construction and operation requirement of "one network nationwide", the grid management objectives are proposed, namely, to focus on safe, efficient and high-quality development, to highlight the "processoriented" and "refined service" concepts, to transversely sort out and integrate production activities, to vertically compress management levels, to build information support systems, and to seek collaborative optimization schemes for resource sharing and business. With reference to foreign advanced experience, it was proposed to take regional management achievements as part of grid management solutions. With gridding, flattening and specialization as the goal, risk management and control as the core, automation, informationization and intelligence as the support, standardization as the effective approach, and improvement of staff quality and initiative as the foundation, the regional management can be continuously promoted in a closed-loop process. The implementation idea of grid management has been raised, that is, to construct the "grid + flat" organizational form, to set up the integrated and interconnected information center system, to establish the comprehensive and unified standard system, to form the intelligent technical support and professional operation & maintenance support system, and to build a high-quality workforce. At present, it is urgent to develop a scientific grid management implementation plan at the level of "one network nationwide" for better serving the company's strategic development goals.