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1
Borodovsky, A. P. « A Bronze Age Shaft-Hole Axe from the Northwestern Baraba Forest-Steppe ». Archaeology, Ethnology & ; Anthropology of Eurasia 50, no 2 (30 juin 2022) : 41–48. http://dx.doi.org/10.17746/1563-0110.2022.50.2.041-048.
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This study introduces a crested shaft-hole axe found on the southern shore of Lake Maidan, Vengerovsky District, Novosibirsk Region. Such random finds are regarded as markers of Bronze Age landscape zones and transportation routes in southwestern Siberia. Shaft-hole axes with slight crests occurred on this territory from the mid to late 2nd millennium BC. In addition to such axes, several casting molds made of clay, stone or metal have been found, possibly suggesting that axes were not only imported but also manufactured locally. These random finds of shaft hole axes can be considered markers of the complex, mirroring not only Middle and Late Bronze Age distribution areas, but also a considerable northward shift of landscape borders during an episode of climatic change, as well as indicating key routes for the migration of people associated with various traditions and objects. The mapping of various subtypes of shaft-hole axes from the Baraba forest-steppe revealed one such route, leading northward from southwestern Siberia to the Vasyugan Swamp. Apart from the series of axes from Baraba, certain cemeteries, such as Stary Tartas-4, yielded miniature replicas used as personal adornments. This feature links the north of the western part of the axes’ distribution area (the forest-steppe zone of the Ob-Irtysh watershed) with its eastern part – the Minusinsk Basin.
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Apakidze, Joni, et Svend Hansen. « Two Bronze Age Hoards with Shaft-Hole Axes from West Georgia ». Slovenská archeológia LXVIII, Suppl. 1 (31 décembre 2020) : 39–52. http://dx.doi.org/10.31577/slovarch.2020.suppl.1.1.
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BERNARDINI, F., A. DE MIN, D. EICHERT, A. ALBERTI, G. DEMARCHI, A. VELUŠČEK, C. TUNIZ et E. MONTAGNARI KOKELJ. « SHAFT-HOLE AXES FROM CAPUT ADRIAE : MINERALOGICAL AND CHEMICAL CONSTRAINTS ABOUT THE PROVENANCE OF SERPENTINITIC ARTEFACTS* ». Archaeometry 53, no 2 (16 mars 2011) : 261–84. http://dx.doi.org/10.1111/j.1475-4754.2010.00547.x.
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Williams-Thorpe, O., P. C. Webb et M. C. Jones. « Non-destructive geochemical and magnetic characterisation of Group XVIII dolerite stone axes and shaft-hole implements from England ». Journal of Archaeological Science 30, no 10 (octobre 2003) : 1237–67. http://dx.doi.org/10.1016/s0305-4403(02)00274-1.
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BERNARDINI, F., A. DE MIN, G. DEMARCHI, E. MONTAGNARI KOKELJ, A. VELUŠČEK et D. KOMŠO. « SHAFT-HOLE AXES FROM SLOVENIA AND NORTH-WESTERN CROATIA : A FIRST ARCHAEOMETRIC STUDY ON ARTEFACTS MANUFACTURED FROM META-DOLERITES* ». Archaeometry 51, no 6 (16 juin 2009) : 894–912. http://dx.doi.org/10.1111/j.1475-4754.2009.00472.x.
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Chindina, L. A., et N. M. Zinyakov. « Cultural and Technological Characteristics of Russian Forged Iron Tools from the Selkup Cemetery Migalka in the Middle Ob Basin ». Archaeology, Ethnology & ; Anthropology of Eurasia 48, no 3 (4 octobre 2020) : 90–98. http://dx.doi.org/10.17746/1563-0110.2020.48.3.090-098.
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This study addresses Russian iron artifacts from the Narym Selkup cemetery Migalka, dating to the late 1600s to early 1700s. Two most important categories of tools are described—knives and axes. In terms of morphology, knives fall into two groups: straight-backed and those with convex (“humped”) backs. The combination of a “humpbacked” blade, typical of native manufacture, and Russian hilt plates precludes an unambiguous ethnic attribution. Special attention is paid to knives with fi ligree-enamel hilt plates as markers of high socio-economic status. The garniture evidences northern Russian origin. The metallographic analysis of knives (22% of the sample) revealed two technological groups: made of solid steel and welded. Axes, made by Russian artisans, are of the shaft-hole type and fall into four types. The analysis, relating to 42% of the sample, indicates two techniques: welding of a steel blade onto an iron base or a piece of raw steel, and using irregularly carbonized metal for forging the entire axe. Ferrous metal items follow the Russian technological traditions. Three key factors accounted for the spread of Russian artifacts among the natives: “Tsar’s gift” for paying the yasak (tribute); colonization of Siberia followed by the emergence of trade manufacture; and the involvement of natives, specifi cally the Narym Selkups, in the all-Russian market. Our fi ndings attest to the relevance of iron artifacts from archaeological sites to the historical and cultural studies of the colonization period in western Siberia.
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Il’inykh, Viktor. « Evaluation of quality parameters of conical profile compounds in nodes of multi-purpose machines ». E3S Web of Conferences 140 (2019) : 02003. http://dx.doi.org/10.1051/e3sconf/201914002003.
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The article presents a study of the mandrel spindle assembly for accuracy, contact stiffness and strength. The study was made on the basis of conical profile connections with an equiaxed contour. Experiments were carried out for multi-purpose machines of various layouts on the basis of the previously developed program-mathematical complex of evaluating the parameters of the shaft-sleeve coupling. The analysis of the simulation modeling results of the accuracy of the shaft (mandrel) installation in the hole of the sleeve (spindle) is carried out taking into account the error in shape, taper, the magnitude of the assembly force and the external conditional load in the spatial setting. With respect to the three coordinate axes, the possible displacements and rotations of the tool mandrels with a modified shank design are determined when they are based and secured in the spindle. In each design case, the accuracy of the relative position of the parts of the conical profile connections was compared during reusable assembly for the horizontal and vertical machine, respectively, and during the operation of the spindle-mandrel assembly under the condition of an external load. As a result of research, it was found that the layout of the machine does not significantly affect the quality parameters of the profile connection in conditions of reusable assembly. A significant effect of the error in the shape of the mating parts of the connection has been determined, which leads to an increase in maximum contact pressures till 22MPa, a displacement of the mandrel along the Z axis up to 25 µm, and a significant influence on the ultimate external load, which leads to elastic displacements of the mandrel along the Y axis to 2 µm for tapering 1:10.
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Preda, Bianca. « Considerations regarding Barrow Burials and Metal Depositions during the Early Bronze Age in the Carpathian-Danube Area ». Hiperboreea 2, no 2 (1 décembre 2015) : 5–51. http://dx.doi.org/10.5325/hiperboreea.2.2.0005.
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Abstract The beginning of the Early Bronze Age brought significant changes in the Carpathian-Danube Area, including new burial customs, a different economy and innovative technologies, most of them with eastern steppe origins. Thus, burial barrows appeared in the landscape raised over rectangular grave-pits, sometimes with wood or stone structures containing individuals lying in contracted or supine position with flexed legs, stained with ochre, rarely accompanied by grave-goods like wares, ornaments or weapons made of stone, bone and precious metals. Among the metallurgical innovations, items such as silver hair rings, copper shaft-hole axes and tanged daggers are considered specific to the new era. However, a careful approach of the deposition contexts of these artifacts, as compared with the eastern space, indicates that in some cases the objects were not just adopted, but reinterpreted and involved in different social practices. This paper aims to analyze the manner in which metal pieces were disposed of and to identify the rules governing this behavior.
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Brown, A., N. M. Soonawala, R. A. Everitt et D. C. Kamineni. « Geology and geophysics of the Underground Research Laboratory site, Lac du Bonnet Batholith, Manitoba ». Canadian Journal of Earth Sciences 26, no 2 (1 février 1989) : 404–25. http://dx.doi.org/10.1139/e89-037.
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The lease area of the Atomic Energy of Canada Limited Underground Research Laboratory covers 3.8 km2 and is located 2.5 km north of the south contact of the Lac du Bonnet Batholith. A shaft to 255 m and 130 boreholes up to 1100 m deep expose the third dimension.The underlying granite is largely of two types: (i) pink porphyritic, which may be biotite rich, gneissic, and (or) xenolithic; and (ii) grey homogeneous and equigranular. Composition layering, including xenolith-rich zones, outlines domes along an antiform trending north-northeast through the western part of the lease area. The southeast-dipping flank underlies the eastern half of the site, including the shaft. Axes of folding trend 065 °and 140°. Homogeneous grey granite, being relatively fresh and unfractured, is associated with a magnetic field that is about 100 nT higher and with a resistivity that is up to 5000 Ω∙m higher than those of other units. A pattern of highs in the magnetic field, caused by the high magnetite content of some xenoliths, can be used to map the antiform.Three thrust faults that dip 10–30° east-southeast are partly controlled by the compositional layering. Anomalies in the very low frequency electromagnetic (VLF-EM) field occur at the surface projections of faults. One fault has been mapped at depth by a high-resolution seismic reflection survey. A suite of downhole geophysical methods, including cross-hole seismic, has been used to map discontinuities in boreholes.Subvertical penetrative foliations and pegmatitic dykes are part of the late crystallization fabric, providing (with filled fractures) a continuous deformation history in response to north- to northeast-trending compressive stress.
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BERNARDINI, F., A. DE MIN, D. LENAZ, P. ŠÍDA, C. TUNIZ et E. MONTAGNARI KOKELJ. « SHAFT-HOLE AXES FROM CAPUT ADRIAE MADE FROM AMPHIBOLE-RICH METABASITES : EVIDENCE OF CONNECTIONS BETWEEN NORTHEASTERN ITALY AND CENTRAL EUROPE DURING THE FIFTH MILLENNIUM BC ». Archaeometry 54, no 3 (18 novembre 2011) : 427–41. http://dx.doi.org/10.1111/j.1475-4754.2011.00637.x.
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Li, Can, Ping Chen, Xin Xu, Xinyu Wang et Aijun Yin. « A Coarse-to-Fine Method for Estimating the Axis Pose Based on 3D Point Clouds in Robotic Cylindrical Shaft-in-Hole Assembly ». Sensors 21, no 12 (12 juin 2021) : 4064. http://dx.doi.org/10.3390/s21124064.
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In this work, we propose a novel coarse-to-fine method for object pose estimation coupled with admittance control to promote robotic shaft-in-hole assembly. Considering that traditional approaches to locate the hole by force sensing are time-consuming, we employ 3D vision to estimate the axis pose of the hole. Thus, robots can locate the target hole in both position and orientation and enable the shaft to move into the hole along the axis orientation. In our method, first, the raw point cloud of a hole is processed to acquire the keypoints. Then, a coarse axis is extracted according to the geometric constraints between the surface normals and axis. Lastly, axis refinement is performed on the coarse axis to achieve higher precision. Practical experiments verified the effectiveness of the axis pose estimation. The assembly strategy composed of axis pose estimation and admittance control was effectively applied to the robotic shaft-in-hole assembly.
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Gangfeng, Zheng, Wu Bolin, Li Ze, Liu Songfeng, Dong Hao et Zhang Haotian. « Three-dimensional reconstruction of a shaft-type deep-small hole with variable aperture based on image processing for ultrasound detection ». Insight - Non-Destructive Testing and Condition Monitoring 63, no 4 (1 avril 2021) : 236–40. http://dx.doi.org/10.1784/insi.2021.63.4.236.
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A method based on image processing for ultrasound detection is proposed to solve the problems of variable aperture and deviation from the axis in deep-small hole machining of shaft components in the field of mechanical manufacturing. First, the deep-small hole echo signals collected in the experiment are converted into polar coordinates and the complete information of each section is extracted. Next, the section is fitted using the least-squares method. Then, the centre track and radius are interpolated. Lastly, three-dimensional data are visualised to realise the three-dimensional reconstruction of a deep-small hole with variable aperture that deviates from the axis. The findings demonstrate that, when machining a deep-small hole in fine-axis components, this method has a good effect on the reconstruction of a hole with variable aperture that deviates from the axis, which is in accordance with the actual situation.
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Václavík, Jaroslav, et Otakar Weinberg. « Residual Stress Measurement on Large Shafts ». Advanced Materials Research 996 (août 2014) : 295–300. http://dx.doi.org/10.4028/www.scientific.net/amr.996.295.
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The review and some experiences are given from measurement and evaluations of residual stresses on large shaft forgings and rail axles using the hole-drilling and ring-core strain-gauge methods, provided by Pilsner Research and Testing Institute, Czech Republic.
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Bobrowski, A. V., O. I. Drachev et I. Yu Amirdzhanova. « ANALYSIS OF THE CHARACTERISTICS OF THE INSTALLATION FOR TWO-HOLE SHAFT PROCESSING ». IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, no 8(243) (28 août 2020) : 23–25. http://dx.doi.org/10.35211/1990-5297-2020-8-243-23-25.
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The article presents the description of the two tool setup for turning axisymmetric parts. The technical result is an increase in the accuracy and productivity of turning due to self-leveling cutting forces on the cutters. This is achieved due to the fact that the installation contains a body and a tool holder of a cylindrical shape, the axis of which is directed perpendicular to the axis of the workpiece. The tool holder is installed in the rolling bearings in the rotating bushing Assembly, which is installed in the housing through the bearings and is connected to the bushing rotation drive. The rotation of the tool holder around its axis relative to the bushing Assembly is limited by the key. Setting the size of the incisors is carried out with a wedge mechanism.
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Yi, Xian Zhong, Song Lin Yi, Hui Shu, Yuan Qiang Ji et Sheng Zong Jiang. « Hydromechanics Analysis with Flow-Field Characteristics of High Pressure Water-Jet in Sloping Bottom Hole of Radial Horizontal Drilling ». Advanced Materials Research 952 (mai 2014) : 190–93. http://dx.doi.org/10.4028/www.scientific.net/amr.952.190.
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According to the principle of fluid dynamics, the Fluent software is used for the numerical simulation analysis of three-dimensional single-hole nozzle submerged jet flow field of radial drilling inclined shaft. The results show that when the bottom is tilted, there are two sizes of spiral along the center axis, and the vortices along tilt direction of the wall are stronger. When the jet source closes the bottom, the kinetic energy of jet is converted into the impact for the bottom of well, making the pressure of bottom hole on the wall have a tendency to rise.
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Borodovsky, A. P. « A Bronze Age Shaft-Hole Axe from the Northwestern Baraba Forest-Steppe ». Archaeology, Ethnology and Anthropology of Eurasia (Russian-language) 50, no 2 (2022) : 41–48. http://dx.doi.org/10.17746/1563-0102.2022.50.2.041-048.
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Статья посвящена публикации и анализу вислообушного топора с гребнем, обнаруженного на южном берегу оз. Майдан (Венгеровский р-н Новосибирской обл.), в контексте аналогичных случайных находок, которые рассматриваются как маркеры естественных границ ландшафтных зон в эпоху палеометалла и транспортных коридоров в бронзовом веке на юге Западной Сибири. Вислообушные топоры со слабовыраженным гребнем бытовали на этой территории в середине — второй половине II тыс. до н.э. Необходимо отметить, что для лесостепного Обь-Иртышья кроме вислообушных топоров характерно наличие серии литейных форм из различных материалов (глины, камня и металла). Данный факт свидетельствует о поступлении на эту территорию не только готовых предметов (топоров), но и литейной оснастки для их местного производства. Случайно найденные вислообушные топоры являются комплексным маркером. Он отражает не только ареал этих предметов в эпоху развитой и поздней бронзы, но и существенное смещение ландшафтных границ на север в очередной период климатических изменений, а также магистральные пути перемещения носителей определенных культурных традиций и их предметного комплекса. Картографирование различных разновидностей вислообушных топоров, найденных в Барабинской лесостепи, позволило выявить одно из древних меридиональных направлений их распространения с юга вплоть до Васюганских болот. Кроме целой серии вислообушных топоров в лесостепной Барабе в погребальных комплексах (Старый-Тартас-4) представлены их миниатюрные реплики-украшения. Этот признак сближает север западного региона (лесостепное Обь-Иртышье) распространения вислообушных топоров в эпоху бронзы на юге Западной Сибири с восточным регионом (Минусинская котловина).
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Zha, Jun, Yaolong Chen et Penghai Zhang. « Relationship between elliptical form error and rotation accuracy of hydrostatic journal bearing ». Industrial Lubrication and Tribology 69, no 6 (13 novembre 2017) : 905–11. http://dx.doi.org/10.1108/ilt-08-2016-0192.
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Purpose The form error of shaft and hole parts is inevitable because of the machining error caused by rotation error of tool axis in machine tools where the elliptical form error is the most common in shaft and bearing bush. The purpose of this paper is to present the relationship between the elliptical form error and rotation accuracy for hydrostatic journal bearing in precision spindle and rotation table. Design/methodology/approach An error averaging effect model of hydrostatic journal bearing is established by using Reynolds equation, pressure boundary conditions, flux continuity equation of the land and kinetic equation of shaft in hydrostatic journal bearing. The effects of shaft and bearing bush on rotation accuracy were analyzed quantitatively. Findings The results reveal that the effect of shaft elliptical form error on rotation accuracy was six times larger than bearing bush. Therefore, to improve the rotation accuracy of hydrostatic journal bearing in spindle or rotation table, the machining error of shaft should be controlled carefully. Originality/value An error averaging model is proposed to evaluate the effect of an elliptical form error on rotation accuracy of hydrostatic journal bearings, which solves the Reynolds equation, the flux continuity equation and the kinetic equation. The determination of form error parameters of shaft and bearing bush can be yielded from finding results of this study for precision design of hydrostatic journal bearings.
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Wu, Yong Xiang. « Research on Calculation System Used in Positioning Error ». Applied Mechanics and Materials 43 (décembre 2010) : 233–37. http://dx.doi.org/10.4028/www.scientific.net/amm.43.233.
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There are two types of positioning benchmark for number of workpiece in fixture: single positioning and aggregate surface positioning. This paper introduces the research and development on calculation system used in positioning error based on single positioning benchmark such as cylinder hole or external surface of cylinder and aggregate surface positioning benchmark such as one surface two holes or axis of shoulder shaft. It plays an important role in improving CAFD function and building the foundation for CAPP/CAFD integrated system.
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Childs, D., et F. Garcia. « Test Results for Sawtooth-Pattern Damper Seals : Leakage and Rotordynamic Coefficients ». Journal of Tribology 109, no 1 (1 janvier 1987) : 124–28. http://dx.doi.org/10.1115/1.3261303.
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Test results consisting of direct and transverse force coefficients are presented for eleven, sawtooth-pattern, damper-seal configurations. The designation “damper” seal refers to a seal which uses a deliberately roughened stator and smooth rotor, as suggested by von Pragenau [1], to increase the net seal damping force. The designation “sawtooth-pattern” refers to a stator-roughness pattern whose cross section normal to the axis of the seal resembles saw teeth with the teeth direction opposing fluid motion in the direction of shaft rotation. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or “dams.” Sawtooth-pattern seals had more damping than smooth seals but less than the round-hole-pattern seals tested previously. Stiffness of sawtooth and round-hole-pattern seals were comparable. Leakage of maximum-damping configurations was greater for sawtooth-pattern than for round-hole-pattern seals; both types of seals leaked substantially less than did smooth seals. If damping is sacrificed, sawtooth-pattern seals can be designed to leak less than round-hole-pattern seals.
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Guo, Shu Xia, Bin Feng, Liang Zhang, Wei Zhang et Lei Wang. « Eccentricity Measurement of Auto-Hub's Pitch Circle ». Applied Mechanics and Materials 431 (octobre 2013) : 121–25. http://dx.doi.org/10.4028/www.scientific.net/amm.431.121.
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In order to measure the eccentricity of auto-hubs center hole and bolt holes, a machine vision system is proposed in this article. Instead of normally used telecentric lens, a perspective lens is used in the vision system because of the large field of view. The eccentricity is calculated by sub-pixel edge extracting and circle-fitting algorithm. A correction method is put forward to compensate the systematic error resulting from the different perspective distortions of the center hole and the bolt holes because of the height difference between the center hole and the bolt holes, as well as the offset between the hubs center shaft and the optical axis of the imaging system. The maximum variation and the standard variation are calculated to analyze the measurement uncertainty. Experiments had shown that the maximum variation and the standard deviation of the corrected measured eccentricity were reduced to 1/6 and 1/8 of those without correction.
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Huang, Shouren, Kenichi Murakami, Masatoshi Ishikawa et Yuji Yamakawa. « Robotic Assistance for Peg-and-Hole Alignment by Mimicking Annular Solar Eclipse Process ». Journal of Robotics and Mechatronics 34, no 5 (20 octobre 2022) : 946–55. http://dx.doi.org/10.20965/jrm.2022.p0946.
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This study focuses on robotic assistance for peg-and-hole alignment with micrometer-order clearance. The objective of the robotic assistance is to cooperate with a human operator based on a coarse-to-fine strategy in which the human operator conducts coarse alignment and the robotic assistance realizes fine alignment. Robotic-assisted fine alignment is achieved by mimicking the process toward annularity of an annular solar eclipse. The first principal axis of a specified image feature (we call it a eclipse feature) is calculated by subtracting the surfaces of a hole part (a small gear with an inner diameter of 1 mm) and a peg part (a shaft with a diameter of 0.95 mm). Accordingly, control strategy is developed to realize accurate alignment. Moreover, the effectiveness of the proposed method is verified by experimental evaluation.
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Song, Ci, Xibin Wang, Zhibing Liu et Hui Chen. « Evaluation of axis straightness error of shaft and hole parts based on improved grey wolf optimization algorithm ». Measurement 188 (janvier 2022) : 110396. http://dx.doi.org/10.1016/j.measurement.2021.110396.
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Shukhanov, S. N., et A. S. Dorzhiev. « Modernization of the apparatus for grinding root crops ». Traktory i sel'hozmashiny 1, no 2 (2021) : 68–72. http://dx.doi.org/10.31992/0321-4443-2021-2-68-72.
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The sustainable functioning of the agro-industrial complex largely determines its scientific and technical support. One of the key directions of the development of agricultural science is the mech-anization of animal husbandry processes. When solving a complex of problems, great attention is paid to the preparation of feed, namely the grinding of root-club crops. This makes it possible to significantly increase the return of each feed unit. As a result of a wide review of literary sources and a thorough analysis of modern designs of root-club grinders, it became possible to solve the technical problem of its modernization by creating a simple as well as reliable design. The peculiarity of the modernization consists in the fact that the electric motor is mounted on the cover of the housing with the help of a flange, which is its component element, besides, the axis of rotation of the shaft structure is aligned with the axis of rotation of the disk structure. Loading hopper is also installed on cover. For this purpose, the cover has a hole for the driving shaft of the electric motor, as well as a window for passage of root clubs from the cavity of the receiving hopper to the space of the housing. Disk is rigidly mounted on free edge of shaft structure. Body is fixed on base by means of uprights vertically and with formation of free space under its bottom and base for installation of unloading neck, as well as reservoir for treated root crops. The discharge neck is structurally made in the form of a funnel with the formation of a conical component at the top and a cylindrical com-ponent at the bottom. In addition, the axis of symmetry of the funnel is aligned with the axis of rotation of the shaft. Its conical component is attached to the outer surface of the bottom structure, and the cylindrical component of the funnel is oriented to the container for the treated material. Concentric holes are made in bottom for passage of processed root crops from cavity of body into structure of discharge neck. The principle of energy saving is carried out by supplying treated fodder to the discharge neck device and further to the receiving vessel mainly due to gravity of the treated fodder.
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Ma, D. K., et S. L. Yang. « Kinematics of the Cone Bit ». Society of Petroleum Engineers Journal 25, no 03 (1 juin 1985) : 321–29. http://dx.doi.org/10.2118/10563-pa.
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Abstract The bits' and bit cones' angular velocities are variable with time. All published papers on cone bit kinematics, however, are based on the supposition that the motions of cones are uniform. This supposition, therefore, has been the main obstacle to determining the objective law of the working cone bit. The apparatus, methods, and tests results for measuring the bit and cone instantaneous angular velocities are described. A new theoretical analysis of cone bit motion is proposed and some interesting new conclusions are obtained that will help designers and users of cone bits. Introduction Although cone bits have been used for more than 70 years, their kinematics and dynamics have not been investigated thoroughly. Unfortunately, many questions, such as the variation of velocity of a bit tooth during its impact against the hole bottom and the distance or velocity of slip between the bit tooth and the hole bottom, both of which concern the designers and users of cone bits, have not been answered explicitly. Many papers on kinematics or dynamics of cone bits proposed that the rotations of bit and cones were proposed that the rotations of bit and cones were uniform. Some papers treated the motion of the cone as a rigid body motion with a fixed point"; others looked on the motion of a tooth-row as a linear rolling. None of these concepts has reflected the actual behavior accurately. In recent years, a few authors have noticed the problem of the nonuniform rotations of cones, but no detailed problem of the nonuniform rotations of cones, but no detailed study has been carried out. This paper discusses the Southwestern Petroleum Inst. Rock Bit Research Laboratory's experimental equipment for measuring the motion of the frill-scale rock bit. and the single-tooth-row roller. Some test results are shown. The relational equations among the kinematic and geometric parameters of the single-tooth-row roller sheet with respect to double frames of reference have been derived by using polar coordinates. These equations are used to explain the test data. Experimental Equipment A square hole is made in the thrust button in each cone of the frill-scale bit. A round hole is made through each journal along its axis. In each journal, a small shaft is inserted in the round hole. The square end of the small shaft is fixed into the square hole in the thrust button and the other end is joined to the shaft of a sensitive DC tachometer generator. A magneto-electric oscillograph is used for recording the output voltage of the tachometer generator. The graph of the instantaneous angular velocities of cones are recorded on film. A drilling machine is converted into testing equipment for studying the kinematics of a single-tooth-row roller. It is shown schematically in Fig. 1. In this figure, (1) denotes the DC motor with stepless speed variation; (2) represents the gear box; (3) shows some large iron disks used to simulate the bit weight and the moment of the upper part of the drillstring; (4) is a sensitive DC tachometer generator joined to (5) and used for measuring the angular speed of the imaginary upper drillstring; (5) is a vertical slender shaft; and (6) denotes a special experimental bit body. (One-, two-, or three-cone assemblies may be fixed on this bit body and their offset may be controlled.) The (7) represents the roller fixed to (8); (8) denotes a shaft that is supported on the bit body by two roller bearings; (9) shows the second sensitive DC tachometer generator used for measuring the angular velocity of the roller; and (10) represents a displacement transducer with strain gauges, which is used for measuring the vertical displacement of the bit body. The information produced by Instruments (4), (9), and (10) shown in Fig. 1 are recorded by an oscillograph on film. Brief Description of Test Results The full-scale bit test results indicated that the angular velocities of cones varied randomly over time and produced large-amplitude oscillations. Fig. 2 gives the produced large-amplitude oscillations. Fig. 2 gives the angular velocities vs. time graphs of the three cones of the rock bit XHP-215Z, taken while drilling in medium-hard sandstone. Careful observation of these graphs shows that the number of angular speed large-amplitude oscillations in one cycle of the cone is equal to or approximately equal to the tooth number in a certain tooth-row on that cone. This tooth-row usually is found in the second or third row of the cone and not in the first (gauge) row, as mentioned in some papers. The total number of oscillations of the cone per cycle usually approximates the total number of teeth on that cone. The tooth-rows are the "cells" of cones and a specific tooth-row plays an important role in the motion of cones. Therefore, a more detailed study of the motion of a single-tooth-row roller is necessary to explain the motion of the rock bits. Valuable results have been obtained from the tests of various rollers under different test conditions. These results generally illustrated that the bit cones' rotation has never been uniform. SPEJ p. 321
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Ye, Min Oo, et Krit Somnuk. « Continuous Hydrosonic Reactor for Methyl Esters Production Process from Low Free Fatty Acid Oil Using 3D-Printed Rotor ». Materials Science Forum 998 (juin 2020) : 140–45. http://dx.doi.org/10.4028/www.scientific.net/msf.998.140.
Texte intégralRésumé :
The continuous methyl ester production process was studied using a hydrosonic reactor to determine the relationship between the rotor speed and the purity of methyl ester with TLC/FID technique. The hydrosonic reactor consisted of three main parts: a rotor, a stator, and a motor. The key part is a 3D-printed rotor; the dimensions were 60 mm in outer diameter, 50 mm in length. The rotating 3D-printed rotor was driven and axially rotated inside the stator by shaft, and 400 kW electric motor was used to blend the mixtures. The dimensions of stator were 70 mm inner diameter and 70 mm length, and 5 mm thickness. The gap distance between the rotor and stator was fixed at 10 mm. The hole on the surface of rotor was circular shape (80 holes of 6 mm diameter) and designed radically throughout the axis. The ratio of diameter to depth of the circular hole was 1.0. In the preliminary experiment, the location and dimension of holes were fixed, and 3D-printed rotor speed was varied at 1000, 2000 and 4000 rpm under the condition of 23 vol.% methanol, 10 g KOH/L and 37 L/hr RPO flow rate at 60°C. The results showed that methyl ester purification reached 93.920 wt.%, 95.325 wt.%, 96.700 wt.%, and 97.333 wt.% at 1000, 2000, 3000, and 4000 rpm of rotor speed. Therefore, over 90 wt.% of methyl esters can be produced from RPO by using rotor-stator type of hydrodynamic cavitation.
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Abdul Rahman Agung Ramadhan et Eko Aprianto Nugroho. « PROSES PEMBUATAN HOUSING BEARING GEARBOX 3Z2M21 DENGAN MATERIAL FCD 400 ». Jurnal Ilmiah Teknik 2, no 1 (16 janvier 2023) : 20–28. http://dx.doi.org/10.56127/juit.v2i1.474.
Texte intégralRésumé :
Fundamental, detailed and in-depth understanding of technology is carried out through the use of concrete pumps used to move fluid from one place to a higher place, high pressure and circulation. One of the important components of the pumping system in the industry is the Gearbox Bearing Housing which functions as a bearing housing so that the bearing can move and continue the shaft work system on the pump. The material used to make the Gearbox Bearing Housing is based on FCD 400. The manufacturing process for the Gearbox Bearing Housing is a lathe where in this process the workpiece is fed by rotating the workpiece and then touching it to a chisel which is moved in translation parallel to the axis of rotation. of the workpiece. The outer diameter is 700 mm, while the inner diameter is 340 mm and D2 is 440 mm. Drilling Machine Process, the machining process is the process of expanding or enlarging a hole that can be done with a drill bar. For the size of the holes, namely the diameter of 22 mm as many as 16 holes, the diameter of 20 mm as many as 16 holes and for the diameter of 12 mm there are 4 holes. Grinding Machine Process is a finishing process that is used to remove parts of the workpiece that are uneven. In the manufacture of Gearbox Bearing Housing, checks are carried out on the workpiece to determine whether or not an item is produced. If the workpiece is said to be feasible, it will be packaged to be marketed, if not, the workpiece will be destroyed.
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Chochorowski, Ja. « «BIRD-HEAD» OR «HORSE-HEAD» SCEPTRES — A REAL OR APPARENT DILLEMA ? » Archaeology and Early History of Ukraine 36, no 3 (2 avril 2020) : 35–78. http://dx.doi.org/10.37445/adiu.2020.03.01.
Texte intégralRésumé :
Thanks to their visual attractiveness the bronze sceptres resembling small axe-heads but enriched with zoomorphic elements rank among the most exclusive and interesting objects of ancient bronzeworking. Late Bronze Age examples of such artefacts are known from two separate regions in Europe: north-west Ciscaucasia (3 pieces) and the Carpathian Basin (7 pieces). Cultural affiliation of these few albeit highly interesting objects was first discussed by J. Werner, who in 1961 characterised Central European finds of «battle axes-batons» when presenting a specimen discovered in an Early Hallstatt grave from Předměřice on the upper Elbe River (Czech Republic). Due to the shape of the top («head»), which resembled a stylised horse head set on an arching neck, he described such objects as «horse-head» sceptres (Pferdekopfszepter). The issue was re-addressed in 1965 by V. A. Ilinskaja, who interpreted the find from Předměřice as a kind of a horseman’s pick. In her opinion, the contours of Pre-Scythian and Scythian sceptres resembled stylised eagle heads, so she introduced the descriptor «bird-headed» (птицеголовые скипетры). All the researchers addressing Central European sceptres terminating in horse heads have been unanimous in noting the absence of local traditions for this type of zoomorphic style in the Late Bronze Age bronze metallurgy of Central Europe. Looking for the original inspiration for such artefacts and for the “horse head” motif, they have commonly pointed to the Caucasus, and in particular to the milieu of the Koban (Protomeotic) culture.
Addressing this issue requires above all the a stylistic analysis of both Central European and Caucasian sceptres, the analysis that would consider similarities and differences observable in the manner of rendering zoomorphic representations. In the case of two sceptres from the Carpathian Basin: found in the Sбrviz channel in eastern Transdanubia and in the Turiec Basin (i. e. in the former komitat of Tъrуc in eastern Slovakia), we are undoubtedly dealing with naturalistic representations of horse heads set on arching necks, with species characteristics clearly discernible. In the approach to stylistic analysis of zoomorphic representations formulated by A. R Kantorovich (2016), these two representations were inspired by the «natural prototype» («природный прототип»), an actual existing animal «model», whose characteristics were imitated by the artist-metallurgist to an extent determined by limitations imposed by the bronze casting technology on the one hand and the artist’s own skills on the other. They are the result of reproducing in bronze either a visual impression elicited by observation of characteristic features of a specific animal, or an image of these animals engrained in common consciousness. The realism of representation is emphasised by elements of harness (straps or perhaps reins) depicted on the necks of both figurines. This is particularly evident when we look en face at the horse head adorning the sceptre from Sбrviz. In contrast, there are absolutely no elements there that would depict in the same realistic manner the head or beak of a bird. The important element in the rendering of the horse head, one which I noted some time ago (Chochorowski 1993), is the clearly marked imitation of the short, stiff mane running along the arching neck.
The diversity of forms among the remaining sceptres known from the Carpathian Basin and adjacent areas is also very telling, in particular with respect to the modelling of the horse head. Relatively similar to each other, the specimens from Prьgy and Sоnmihai de Pădure show simplification and certain reduction of species characteristics in the head itself, although the mane crowning the massive neck is still well-discernible. As in the pair of sceptres discussed above, they also have clearly marked pointed ears. In the sceptres from Batina and Předměřice, the head is almost undiscernible from the neck in outline, and the mane modelling is all but vestigial. In the artefact from Batina it is only marked as a narrow ridge running along the curved neck all the way from the shaft hole to the end of the «head», with the ears (?) marked by two small knobs, one on each side. If we follow Т. Kemenczei (2005) in including to this group a stray find from Bйkйs-Hagymбsi, we have an example which, while maintaining the overall morphological form of a sceptre with a «blunt» head, shows total disappearance of the zoomorphic motif. Apart from the mushroom-shaped butt and a similar termination of the curved «socket», the only similarity between this artefact and the naturalistically modelled examples discussed above is the fact that the «base» of the neck or mane (?) seems to be distinguished by mouldings. As a result, at the end of the process the original idea becomes represented by the very shape of a sceptre, and it expresses the same symbolism as the naturalistic artefacts.
The above analysis seems to prove that the collection of bronze sceptres from the Carpathian Basin represents an autonomous phenomenon, revealing internal changeability consistent with logical principles of a «typological sequence / line». Gradual departure from the naturalistic manner in representing the «natural prototype» of a horse head was probably due to the trivialisation of the motif which, initially innovative, with time became common and lost its «communicative freshness» in social narration. The owners of sceptres maintained their status by the very fact of their ownership, without a need for manifesting the iconographic symbol of the role and social function attached to the sceptre.
Thus, the bronze sceptres from the Carpathian Basin are a fully autonomous phenomenon, one which emerged at some point point at the second half or end of the 10th century as a sort of indicator of the new social-cultural order. The main characteristics of this new order included a pastoral economy with an important role (important enough to influence the European system of distribution of goods — Sherratt 1993) of selective breeding of horse breeds of steppe origins, and hierarchic social structures with distinct status markers. These characteristics are rooted in the cultural identity of Great Steppe communities, shaped by specific environmental conditions and a long — sometimes reaching as far back as the Eneolithic — accumulation of existential experience. As a result of migrations of aggressive groups of steppe shepherd-warriors looking for ecological niches advantageous to their pastoral economy, these characteristics were «implanted» into the Carpathian Basin in the second half of the 10th century. With time, the newcomers became integrated with local populations, contributing to the integration process with their own package of social-cultural behaviours. Their contribution was particularly evident in the sphere of specialised horse breeding and outstanding skills in using these animals, both for riding and traction (Chochorowski 1987). This package of achievements and cultural experience was an important innovation in the European spectrum of economic strategies and, in a short time (maximum two generations), allowed for full integration of the «steppe people», and for the adoption of a significant portion of their civilisational package in the local environment.
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Pfau, Axel, Joel Schlienger, Anestis I. Kalfas et Reza S. Abhari. « Virtual four sensor fast response aerodynamic probe (FRAP®) ». E3S Web of Conferences 345 (2022) : 01014. http://dx.doi.org/10.1051/e3sconf/202234501014.
Texte intégralRésumé :
This paper introduces the new fast response aerodynamic probe (FRAP®), which was recently developed at the ETH Zurich. The probe provides time-resolved, three-dimensional flow measurements using the virtual four sensor technique. Two probes work in tandem, being comparable to a pair of pneumatic needle probes. The first probe, being yaw angle sensitive, is positioned in three circumferential positions. The second probe being pitch angle sensitive is brought into exactly the same position as the first probe. The resulting set of four measurements is phaselock-averaged to one specific rotor trigger position. Then the reduced data sets are combined to four calibration coefficients, which are then further processed to determine the unsteady flow vector. The results consist of yaw and pitch flow angles as well as the total and static pressure. The outer diameter of the cylindrical probe head was miniaturized to 0.84mm, hence probe blockage effects as well as dynamic lift effects are reduced. The shape of the probe head was optimized in view of the manufacturing process as well as aerodynamic considerations. The optimum geometry for pitch sensitivity was found to be a cylindrical surface with the axis perpendicular to the probe shaft. The internal design of the probes led to a sensor cavity eigen frequency of 44 kHz for the yaw sensitive and 34kHz for the pitch sensitive probe. The steady aerodynamic characteristics of the probe were measured using the free jet probe calibration facility of the laboratory. The full set of calibration surfaces is given. Data acquisition is done with a fully automated traversing system, which moves the probe within the test rig and samples the signal with a PC-based A/D-board. An error analysis implemented into the data reduction routines revealed acceptable accuracy for flow angles as well as pressures for many turbomachinery flows. Depending on the dynamic head of the application the yaw angle is accurate within ±0.35° and pitch angle within ±0.7°. Finally, a comparison of time averaged results to five hole probe measurements is discussed.
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Renfrew, Colin, Olga Philaniotou, Neil Brodie et Giorgos Gavalas. « The Early Cycladic Settlement at Dhaskalio, Keros : Preliminary Report of the 2008 Excavation Season ». Annual of the British School at Athens 104 (novembre 2009) : 27–47. http://dx.doi.org/10.1017/s0068245400000198.
Texte intégralRésumé :
The 2008 excavations on the small island of Dhaskalio opposite Dhaskalio Kavos on the Cycladic island of Keros are reviewed. An account is given of the survey, recording many walls of the early Bronze Age, and of the excavations, continued from the 2007 season. Excavations at the summit of Dhaskalio revealed a substantial building 16 m long and 4 m wide, within which was discovered the ‘Dhaskalio hoard’ comprising a chisel, an axe-adze, and a shaft-hole axe of copper or bronze. Study of the pottery reveals continuity, within which a sequence of three phases within the Early Cycladic II and III periods can be established.Excavations were continued and concluded within the Special Deposit at Kavos South with the recovery of many more special but fragmentary materials including marble vessels and figurines. Specialist studies for the geomorphology, geology, petrology, ceramic petrology, metallurgy and environmental aspects (botanical and faunal remains, phytoliths) are in progress. No more fieldwork is planned prior to final publication of the 2006 to 2008 seasons.Στο άρθρο ετηχειρείται ένας συνοπτικός απολογισμός των ανασκαφών της περιόδου του 2008 στην νησΐδα Δασκαλιό, απέναντι από τον Κάβο Δασκαλιού, στο ΝΔ άκρο της νήσου Κέρου, των Κυκλάδων. Περιληππκά αναφέρονται τα αποτελέσματα της τοπογράφησης με τον εντοπισμό πολλών τοίχων της Πρώψης Εποχής του Χαλκού, αλλά και αυτά της ανασκαφής, η οποία αποτελεί την συνέχεια των ανασκαφών του 2007. Κατά τις ανασκαφές στην κορυφή του Δασκαλιού αποκαλύφθηκε ένα ευμέγεθες κτήριο μήκους 16 μέτρων και πλάτους 4 μέτρων, εντός του οποίου βρέθηκε ο ‘Θησαυρός του Δασκαλχού’, ο οποίος αποτελείται από μία σμίλη, μία αξίνα-πέλεκυ, κοα έναν πέλεκυ με συμφυή οττή για την τοποθέτηση του στειλεού, όλα χάλκινα ή μπρούτζινα. Η μελέτη της κεραμικής απέφερε σημαντικά αποτελέσματα και απέδειξε ότι υπάρχει συνέχεια. Η αυτή ίδια μελέτη κατέδειξε μία ακολουθία τριών φάσεων, οι οποίες χρονολογήθηκαν από την Πρωτοκυκλαδική II έως και την Πρωτοκυκλαδική III περίοδο.Οι ανασκαφές στον Κάβο Δασκαλιού συνεχίστηκαν και ολοκληρώθηκαν στην περιοχή της Νότιας Ειδικής Απόθεσης με την αποκάλυψη πλήθους ιδιαίτερων, αλλά αποσπασματικά σωζόμενων, ευρημάτων, μεταξύ των οποίων, πολλών μαρμάρινων αγγείων και ενδοίλίων.Οι εξειδικευμένες μνκρομορφολογικές-γεωαρχαιολογικές, γεωλογικές και πετρογραφικές μελέτες, αλλά και οι αναλύσεις πηλού και οι μελέτες, που αφορούν στην αρχαιομεταλλουργία και στο παλαιοπεριβάλλον (αναλύσεις των καταλοίπων της χλωρίδας και της πανίδας αλλά και των φυτολίθων), βρίσκονται σε εξέλιξη. Άλλες έρευνες επί του εδάφους προς το ηαρόν δεν προγραμματίζονται, πριν από την ολοκλήρωση της τελικής δημοσίευσης των αποτελεσμάτων των ερευνών των περιόδων 2006 έως και 2008.
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Alesker Jabarov, Alesker Jabarov. « INVESTIGATION OF WELLS IN THE WORKING FUND OF “AZNEFT” PU AND PROPOSAL OF ANTI-SAND MEASURES ». PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 13, no 02 (1 mars 2022) : 44–51. http://dx.doi.org/10.36962/pahtei13022022-44.
Texte intégralRésumé :
One of the most common complications during the operation of wells in oil fields is the formation of sand. During the formation of sand wells, time stops, their repair takes a long time, as a result, there is a significant loss of production of the well. A floating sand with liquid entering the bottom of a well, destroys the working equipment, loses speed and breaks down at the bottom of the well, forming a sand plug. Removal of sand plugs requires a lot of labor, but sometimes leads to the loss of oil in many wells and the destruction of rocks in the subsurface zone of wells and deformation of the operating pipeline. One of the most pressing problems in the oil industry today is to prevent rock particles from collapsing in the wellbore area and sand accumulation. Despite numerous scientific studies and mining experiments on the sand prevention mechanism, no universal method of sand control has been found. Studies show that the load on the walls of the protective pipeline is the main cause of failure of wells as a result of deformation of the pipeline within the operating facility. Sand block formation during the operation of fragile, poorly cemented reservoirs is an important factor in the close relationship between production line deformation and sand block formation in the well, which requires consideration of the geological and operational characteristics of the field an object. The internal structure of the formation usually changes before the collector rocks are washed away by the infiltration stream. Changes in rock structure during the filtration process occur as a result of mechanical suffocation and compaction of rocks (separation of particles in the rock under the influence of pressure gradients during the movement of oils containing heavy particles in the formation). The most effective way to combat wellhead flushing and sand blockage is to reduce the amount of fluid removed from the formation. This is due to the regulation of the pressure drop in the wellbore. Rock collapse is accompanied by the introduction of sand grains into the wellbore, thereby continuously reducing the permeability of the wellbore zone. However, the sharp decline in well yields is not due to a decrease in the permeability of the formation, but to the high resistance created by the blockage, which closes the filter section and is formed by small sand grains. Colmatization of mechanical mixtures in the wellbore area, contamination of the wellbore, increased vibrations and more intensive wear of the equipment inside the well create serious complications. Despite the widespread use of rod depth pumps, their operation in sand wells is complicated. As a result, the voltage on the rods and the electric motor increases, the rods are stretched, broken, the pliers are idle, the electric motor is overloaded, and so on. occurs. The formation of sand plugs is more pronounced in the final stages of field development. At the moment, due to the sand plugs in the wells, they often stop for repairs, which reduces of the time between repairs and increases the over-all operating costs. Therefore, one of the most pressing issues facing oil workers is to study the causes of sand plugs, to investigate the processes taking place in the plug zone and to develop effective methods to combat sand by analyzing the operation of such wells. If the sand completely closes the filter of the production casing and as a result the flow of liquid to the bottom hole is completely stopped, such a complication can be eliminated by either washing the bottom hole or strengthening the well hole zone. However, in many cases this technology does not work or is not cost-effective. Based on the results of the study, indicator diagrams or graphs of changes in the percentage of oil, water, gas and sand are plotted depending on the pressure in the well or the dynamic level, as well as adjustment curves, i.e. graphs of the dependence of these indicators on the parameters of deep pumping. According to the results of studies carried out by measuring the dynamic level of a deep pump, an indicator diagram can be constructed using the method. This method consists of recording dynamic levels on the same scale selected on the vertical axis, plotting the level drops on the right axis, and recording the percentages of liquid, oil, water, gas, and sand on the horizontal axis. The amount of sand recovered can be expressed in volumes or units of weight. Liquid, oil and water debits should be taken on the same scale. They select the appropriate scale for gas and GOR as well as the percentage of sand, and the level drawdown (difference between static and dynamic levels) is also determined as fluid levels are measured from the wellhead. In order to investigate the impact of mechanical mixtures on the operation of the pump and to determine the measures to be taken, information was collected on the repairs carried out in the shaft depth pump wells on the of “Azneft” PU. Keywords: sand, pump, plunger, cylinder, pump-compressor pipes, mechanical particles, coagulation.
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Hung, George K. « Effect of Putting Grip on Eye and Head Movements During the Golf Putting Stroke ». Scientific World JOURNAL 3 (2003) : 122–37. http://dx.doi.org/10.1100/tsw.2003.14.
Texte intégralRésumé :
The objective of this article is to determine the effect of three different putting grips (conventional, cross-hand, and one-handed) on variations in eye and head movements during the putting stroke. Seven volunteer novice players, ranging in age from 21 to 22 years, participated in the study. During each experimental session, the subject stood on a specially designed platform covered with artificial turf and putted golf balls towards a standard golf hole. The three different types of grips were tested at two distances: 3 and 9 ft. For each condition, 20 putts were attempted. For each putt, data were recorded over a 3-s interval at a sampling rate of 100 Hz. Eye movements were recorded using a helmet-mounted eye movement monitor. Head rotation about an imaginary axis through the top of the head and its center-of-rotation was measured by means of a potentiometer mounted on a fixed frame and coupled to the helmet. Putter-head motion was measured using a linear array of infrared phototransistors embedded in the platform. The standard deviation (STD, relative to the initial level) was calculated for eye and head movements over the duration of the putt (i.e., from the beginning of the backstroke, through the forward stroke, to impact). The averaged STD for the attempted putts was calculated for each subject. Then, the averaged STDs and other data for the seven subjects were statistically compared across the three grip conditions. The STD of eye movements were greater (p < 0.1) for conventional than cross-hand (9 ft) and one-handed (3 and 9 ft) grips. Also, the STD of head movements were greater (p < 0.1; 3 ft) for conventional than cross-hand and one-handed grips. Vestibulo-ocular responses associated with head rotations could be observed in many 9 ft and some 3 ft putts. The duration of the putt was significantly longer (p < 0.05; 3 and 9 ft) for the one-handed than conventional and cross-hand grips. Finally, performance, or percentage putts made, was significantly better (p <0.05; 9 ft) for cross-hand than conventional grip. The smaller variations, both in eye movements during longer putts and head movements during shorter putts, using cross-hand and one-handed grips may explain why some golfers, based on their playing experience, prefer these over the conventional grip. Also, the longer duration for the one-handed grip, which improves tempo, may explain why some senior players prefer the long-shaft (effectively one-handed grip) putter.
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Pischan, Matthias. « Deburring of Cross Holes in Titanium Using Industrial Robots ». Advanced Materials Research 769 (septembre 2013) : 147–54. http://dx.doi.org/10.4028/www.scientific.net/amr.769.147.
Texte intégralRésumé :
In aircrafts, hydraulic systems control moveable parts. For example parts like the front strut or the landing flaps. These parts are usually made from aluminium or titanium. Due to an increasing number of functions these valves show an increasing number of cross holes. The production process causes burrs at the intersection of the holes. Until now these burrs cant be removed reliably by an automated process. Remaining burrs can influence dimensional tolerances and reduce the efficiency and technical lifetime of the component. In some applications cross holes are used for the lubricant and coolant supply. In this case burrs can lead to blockades of critical passages or cause turbulences in the fluid. This can lead to leakage or bursting of the valve. Hence an uncontrolled removal of the burr during operation must be avoided. The consequence of these basic conditions is a time consuming manual deburring process. An automated deburring process of cross holes with industrial robots is usually performed with flexible abrasive brushes. Alternatively processes like AFM (Abrasive Flow Machining), ECM (Electro Chemical Machining) or TEM (Thermal Energy Machining) are used. Those processes are very efficient but require specialized equipment and cleaning processes for the used chemicals and the remaining abrasive paste. So they are not suitable for the deburring of safety related parts. This paper presents an experimental based approach for the robot based deburring of cross holes using industrial robots. For the deburring of cross holes several special tools are available. This article gives a short overview over the specific advantages and disadvantages of these tools. As the investigations revealed the best results can be achieved using the so called Orbitool developed by JWDone. The Orbitool is a tungsten carbide cutter developed for the deburring of cross holes. A better control of the required dimension at the intersection compared to brushes and other deburring methods is possible. Furthermore the tool can be used on machine tools and industrial robots and is flexible to a huge variety of bore diameters. The tool mainly consists of a ball shaped carbide milling cutter with a protective disk which is made of polished steel and a shaft of tool steel. To remove the burr the tool is moved along the bore axis into the smallest of the intersecting holes until the tip of the tool is close to the intersection. Then the tool is moved in radial direction to the bore surface until the tool axis corresponds to the interpolation diameter. This causes a deflection of the tool. In this situation only the protective disk is in contact with the bore surface. While the tool rotates it is moved towards the intersection in a helical motion. When the tool tip has reached the intersection the cutting edges get in contact with intersection and the deburring process begins. After the tool has passed the whole intersection it stops its rotation and is moved to the bore hole centre and then moved out of the workpiece. This paper deals with the optimization of the deburring process. The result mainly depends on the parameters movement speed of the robot, slope of the helical movement and rotational speed of the tool. The experiments are planned using DOE (Design Of Experiment) methods. Initial values for the optimization of the movement speed were determined by grid encoder measurements. Robotic specific parameters like the number of interpolating points and the influence of the path smoothing caused by the controller were also investigated. For the analysis of the burr and the secondary burr an optical 3-D measurement system is used. The results show that with the presented approach the burrs can be reliably removed. Before the deburring process the average burr height is about 60 μm and can be reduced so that there is no secondary burr visible. The result is a chamfer between 150 μm and 85 μm that depends on the process parameters. It can be demonstrated that a chamfer that is smaller than 100 μm leads to a secondary burr. Anyway the cycle time can be reduced from about 3 minutes for manual deburring to 30 seconds using an industrial robot. Additional wear analysis show that about 200 bore holes can safely be deburred.
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Xiao-feng, Sun, Qiao-bo Hu, Jingyu Qu, Wei Li, Ning Mao et Guoshuai Ju. « Optimal Design of Magnetic Torque for a Hydraulic-Magnetic Rotary Hole Cleaning Tool in Horizontal Drilling ». SPE Drilling & ; Completion, 1 septembre 2021, 1–12. http://dx.doi.org/10.2118/206752-pa.
Texte intégralRésumé :
Summary The cleanliness of wellbore is a key factor in the drilling speed and quality of an oil field, especially in long horizontal sections of horizontal wells. Therefore, a hydraulic-magnetic rotary hole cleaning tool has been designed that does not rely on the rotary action of the drillpipe and could be used with a downhole motor to improve hole cleaning efficiency. However, the influence of magnet shape on the transmission of magnetic torque has remained unclear, such that the magnetic shaft transmission torque needed to be optimized to ensure efficient tool operation. In this study, magnetic field control equations were established in the region of the permanent magnet and air gap, and the magnetic flux distribution and magnetic torque generated between two magnetic axes in each field were calculated. Also, the influence of various magnetic field parameters on magnetic torque conduction of a strip magnet were compared and analyzed and then confirmed by comparison with experimental results. The results showed that the magnetic torque transmitted by strip magnets varied sinusoidally with magnetic axis deviation angles and that the highest torque was generated in the 12-pole model. However, the rate of increase in magnetic torque with magnet thickness was opposite to that of tile magnets, increasing with increasing magnet thickness. Magnetic torque variation with covered area was specific in the 6-pole model, showing a tendency of increasing and then decreasing. When magnet thickness was 12 mm and magnet coverage area in the effective cross section of the tool was 80%, the highest magnetic torque/unit volume of magnet was generated for achieving economic optimization. The results led to conclusions that, by solving the regional magnetic field, the magnetic torque change characteristics during movement of the magnetic drive mechanism of the hydraulic-magnetic rotary hole cleaning tool were simulated successfully and that these results could be used as an optimization analysis method for the magnetic drive mechanism of such tools.
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Frost, Lise, Gry H. Barfod et Marie Kanstrup. « Bronzealderens hjortetaksøkser – datering og deponeringsforhold ». Kuml 68, no 68 (29 avril 2021). http://dx.doi.org/10.7146/kuml.v68i68.126028.
Texte intégralRésumé :
Breonze Age antler axes – dating and depositional context
Antler axes are typically associated with the Mesolithic, but this article presents a group of antler axes from the Danish Bronze Age, when this artefact type surprisingly turns up again after an absence from the tool inventory of more than 2000 years (fig. 1).
These artefacts may be found in pits in a settlement context, but the typical finds contexts for the 155 recorded Bronze Age antler axes are rivers/watercourses, lakes and wetland areas, where the axes have been deposited individually, in line with the Bronze Age’s other major group of singly-deposited objects (figs. 2-3). This close relationship with water is linked to the European river finds, as antler axes are not solely a Danish phenomenon but are found across large parts of Europe during the Bronze Age, with the axes typically being deposited singly in running water. In both a Danish and a European context, the axes disappear again in the Iron Age.
This article gives an account of the Danish antler axes in relation to their distribution, finds circumstances and typological characteristics, together with a couple of metal analyses and several new 14C dates for antler axes. The antler axes from the Bronze Age vary in appearance; they may or may not be polished and may or may not be ornamented. They do though have certain features in common, for example they are characterised by a down-turned butt. The shaft-hole can either be round or rectangular and is located a long way back on the axe. They were typically hafted as axes rather than adzes, and their ornamentation frequently consists of point-circle motifs, where pitch has been inlaid to give contrast (figs. 4-8). In a very few cases, metal may form part of the ornamentation. Two results are presented here of micro-XRF analyses of, respectively, inlays of tin and bronze (figs. 9-14).
A significant part of the project focussed on dating of the Bronze Age antler axes. Only a couple of dates had been published previously, both of which fell in the Late Bronze Age. The new dates clearly show, however, that antler axes are a very consistent phenomenon through both the Early and the Late Bronze Age. Dating involves drilling material out for analysis, and in the case of antler and bone there is sometimes a requirement for a sample of as much as 600-800 mg for a date to be obtained. To avoid drilling unnecessary holes in the often aesthetically impressive and eminently exhibitable artefacts such as these, a staged methodological approach was adopted in this project, which involved two-step sampling for radiocarbon dating. Firstly, a very small sample of 5-20 mg was taken for a so-called EA-IRMS analysis. This reveals the preservation condition of the material and thereby the amount of material required to obtain an actual 14C date. In all cases, this preliminary analysis showed that only 100 mg of material had to be drilled out for the actual dating process. This method can therefore be warmly recommended for the dating of bone and antler objects such as these (figs. 15-16).
The dates have revealed that antler axes are present in both the Early and the Late Bronze Age. Moreover, the dates could be used in a clarification of the depositional circumstances. As already mentioned, the antler axes typically represent single depositions, but sometimes two axes are found relatively close together and, based on the finds circumstances, are therefore interpreted as single-type depositions. It has now been possible in some cases to date both axes: For example antler axes found together in sediment dug up during the dredging of rivers/watercourses (Ryå and Odense Å), or discovered close together during peat cutting (Jorløse Mose) or within the same area of reclaimed lake (Søborg Sø). The dates obtained in these cases suggest that these finds represent repeated single depositions within the same area rather than simultaneous deposition of two axes. The phenomenon of returning, in a depositional context, to specific areas in the natural landscape, sometimes at intervals of several hundred years, appears to be a general feature of the Bronze Age – both in Denmark and in Europe as a whole (figs. 17a-22).
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Кореневский, С. Н., et Ш. О. Давудов. « THE EARLY BRONZE AGE SETTLEMENT AND THE GRAVE NEAR THE VILLAGE OF STAROTITAROVSKAYA, THE KRASNODAR REGION AND BURIAL DISCOVERED AT THE SITE ». Краткие сообщения Института археологии (КСИА), no 255 (15 juin 2019). http://dx.doi.org/10.25681/iaras.0130-2620.255.127-138.
Texte intégralRésumé :
В статье представлена публикация новых находок эпохи раннего бронзового века на поселении у станицы Старотитаровской Краснодарского края. Культурный слой поселения плохо выражен и нарушен поселением античного времени. К эпохе раннего бронзового века относится обломок каменного топора, кремневая пластина, несколько сосудов с формовочной массой без минеральных примесей и с минеральными примесями. Судя по ним, поселение датируется концом IV тыс. до н. э. Среди форм керамики присутствуют сосуды с круглым и плоским дном. В яме 58 Б расчищены 4 скелета людей: трех мужчин и юной женщины. Эти находки ставят вопрос об особых формах погребальной обрядности у местного населения и их соотнесения с погребальными традициями майкопской культуры. The paper publishes new Early Bronze Age finds excavated at the settlement near the village of Starotitarovskaya in the Krasnodar region. The cultural attribution of the occupation layer of the settlement is not easily identifiable it was strongly disturbed by a settlement dating to the Classical period. A fragment of a stone shaft hole axe, a retouched flint blade and several vessels made from clay tempered with mineral admixture and clay tempered without mineral inclusions were dated to the Early Bronze Age. Based on these finds, the settlement was attributed to the end of the 4th mill. BC. Pottery finds include several vessels with a round and flat bottom. Four skeletons were discovered in pit 58 B: skeletons of three males and a skeleton of one young woman. These finds raise an issue of special forms of funerary rites practiced by the local population and their correlation with funerary traditions of the Majkop culture.