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2021 ◽  
Vol 1039 ◽  
pp. 159-164
Author(s):  
Ahmed A. Taher

A metal extrusion was process that extrusion puncture perforate surface of material to throw and flow across outlet of die. This operation was a complex process in extrusion while penetration occurred at same time. This process can be seen in many production operations, like in forming of making portion of metal strip, and forming of extruded portion in a complex fineblanking with extrusion operation. Also exhibit the operation properties and give the method of numerical solution. So increasing load to 610KN with increased friction factor to 0.7 and increased with increasing the reduction ratio and stroke of operation. For the results and mesh distortion, with allocations of strains may be predicted. Analyzing results was submitted of metal extruded may be classified into two zones for the different lineaments deformation. moreover, energy in the zones of deformation may be classified into two parts for their different lineaments of internal zone and contact zone with the die . Fracture location has been found from simulations. Keyword Load, Extrusion, upper bound, numerical solution


2021 ◽  
Vol 2 (2) ◽  
pp. 1733-1740
Author(s):  
Lazo Gabriel E. ◽  
Abal Adrián A ◽  
Belloni Federico ◽  
Merlo Diego A ◽  
Barceló Miguel A ◽  
...  

In previous studies, it has been shown that the microstructure of prismatic dental enamel presents differences between the external and internal zone. Radial enamel is found in the outer third of enamel and has higher microhardness values than enamel with Hunter- Schreger Bands (HSB) that occupies the inner 2/3. Our aim was to evaluate the mechanical behavior of radial enamel and HSB due the action of a non-alcoholic beverage in vitro. Longitudinal sections of dental crowns were embedded in polymer, worn and polished with sandpapers of decreasing granulation. The samples were immersed in a flavoured natural water for 12 minutes. Nanohardness tests (Triboindenter Hysitron) were performed on the radial and HSB enamel before and after the exposure to the drink. Hardness determinations "H", reduced modulus "Er" and contact depth "hc" were obtained. The percentage of reduction of hardness was determined. The values found in healthy radial enamel were H: 5.48±0.23 GPa; Er: 86.97±8.11 GPa; hc: 149.73±4.25 nm and in HSB H: 4.24±0.43 GPa; Er: 75.24±7.09 GPa; hc: 176.36±11.29 nm. After exposure to beverage, it was found in the radial enamel H: 2.22±0.31 GPa; Er: 58.73±10.79 GPa; hc: 270.29±21.22 nm, and in HSB H: 1.54±0.42 GPa; Er: 48.11±6.54 GPa; hc: 350.10±63.33 nm. After the drink action, the values of hardness of the radial enamel and HSB decreased and the trend observed in healthy enamel remained, where the highest values corresponded to the radial enamel. The percentage reduction of H in the radial enamel was 59.48% and in the HSB enamel it was 63.67%. The contact depth increased by about 50%.The decrease in hardness is related to the mineral loss produced by the acids contained in the drink. We conclude that the action of the non-alcoholic beverage produces a decrease in the mechanical properties in both the radial enamel and the HSB. The lower values in the reduced module Er indicate the formation of a superficial softened layer, the enamel with HSB being more vulnerable.


2021 ◽  
Author(s):  
Quentin Brunsmann ◽  
Claudio Rosenberg ◽  
Nicolas Bellahsen ◽  
Laetitia Le Pourhiet

<p>The Alps have an overall East-West orientation, which changes radically in their western termination, where they rotate southward into a N-S strike, and then eastward into an E-W strike, forming the arc of the Western Alps. This arc is commonly inferred to have formed during collision, due to indentation of the Adriatic plate into the European continental margin. Several models attempted to provide a kinematic explanation for the formation of this arched, lateral end of the Alps. Indeed, the radial nature of the transport directions observed along the arc of the Western Alps cannot be explained by a classic convergence model.<br>For more than 50 years the formation of this arc was been associated to westward-directed indentation of Adria, accommodated along East-West oriented strike-slip faults, a sinistral one in the South of the arc and a dextral one in the North. The dextral one correspond to the Insubric Fault. The sinistral strike-slip zone, inferred to be localized along the «Stura corridor» (Piedmont, Italy) would correspond to a displacement of 100 to 150 km according to palaeogeographical, and geometric analyses. However, field evidence is scarce and barely documented in the literature.<br>Vertical axis rotations of the Adriatic indenter also inferred to be syn-collisional could have influenced the acquisition of the morphology of the arc. Paleomagnetic analyses carried out in the Internal Zone and in the Po plain suggest a southward increading amount of counter-clockwise rotation of the Adriatic plate and the Internal Zone, varying from 20°-25° in the North to nearly 120° in the South.<br>Dextral shear zones possibly accommodating this rotation in some conceptual models is observed in several places below the Penninic Front and affect the Argentera massif to the south. However, the measured displacement quantities do not appear to be equivalent to those induced by such rotations.<br>The present study aims to constrain the kinematic evolution of the arc of the Western Alps through a multidisciplinary approach. The first aspect of this project is the structural analysis of the area (Stura corridor) inferred to accommodate large sinistral displacements allowing for the westward indentation of the Adriatic indenter. We discuss the general lack of field evidence supporting sinistral strike-slip movements, in contrast to large-scale compilation of structures suggesting the possible occurrence of such displacement. The second part consists of a palaeomagnetic study, in which new data are integred with a compilation of already existing data. This compilation shows that several parts of the arc in the External Zone did not suffer any Cenozoic rotations, hence suggesting that a proto-arc already axisted at the onset collision, as suggested by independent evidence of some paleogeographic reconstruction. Finally, 2D and 3D thermo-mechanical modeling in using the pTatin3D code is used to test which structural (geometrical), and rheological parameters affected the first-order morphology of the Western Alpin arc and its kinematics. The synthesis of these different approaches allows us to propose a new model explaining the kinematics and the mechanisms of formation of the Western Alps arc.</p>


2020 ◽  
Vol 195 ◽  
pp. 105723
Author(s):  
Mª. Dolores Rodríguez-Ruiz ◽  
Isabel Abad ◽  
María Bentabol ◽  
Mª. Dolores Ruiz Cruz

CORROSION ◽  
10.5006/3493 ◽  
2020 ◽  
Vol 76 (7) ◽  
pp. 666-677
Author(s):  
Zbigniew Sawłowicz ◽  
Łukasz Malinowski ◽  
Andy Giże ◽  
Jan Stanek ◽  
Jerzy Przybyło

Metal fragments (pipe, chain, valves), at advanced stages of corrosion, were collected underground in the Wieliczka salt mine. Macroscopically distinct zones of corroded material, as well as black blisters on the surface of different metal fragments, were studied using scanning electron microscopy with energy dispersive spectrometry (SEM-EDS), x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Mössbauer spectroscopy (MS). SEM-EDS studies showed various morphological forms with different chemical compositions. The original outer zone of the iron artifacts is mainly composed of aggregates of needle-shaped goethite crystals with idiomorphic crystals of halite. A subsequent zone, toward the inner margin, is composed mainly of fine granular aggregates of magnetite. Goethite (α-FeOOH) and akaganeite (β-FeOOH) form spherical, fibrous, and structureless aggregates in the next internal zone. Forms of aggregates seem to depend on the chloride content, 1 wt% to 3.5 wt% Cl in the structureless aggregates and 5 wt% to 9 wt% Cl in the regular ones. In addition, in the internal zone crystals of lepidocrocite form rosettes. Blisters are built of the acicular akaganeite crystals, which form fibrous aggregates in the shell and spherical ones in the interior. The relative concentrations of iron bearing minerals in the studied zones, i.e., akaganeite, hematite, goethite, magnetite, and lepidocrocite are established. Where they dominate, the zones are: black (magnetite), orange (goethite, lepidocrocite, akaganeite), and light brown (goethite).


Author(s):  
G.N. Tovarnykh

The paper considers the problem of pressure variations in circular and rectangular flat fractures filled with liquid as the liquid crystallises, taking into account rigidity of the solid phase forming. We suppose that as a liquid crystallises, the volume it occupies inside the fracture changes due to the difference in density of the solid and liquid phases, and the fracture walls deform due to the pressure difference between the environment and the internal zone. Assuming that the solid and liquid phases are incompressible, we may equate the change in the internal fracture volume caused by the deformation of the surrounding walls to that in the volume of the liquid undergoing a state transition. We presume that crystallisation occurs at the top of the fracture, the temperature of the liquid is constant and equals its crystallisation temperature, and the phase boundary between the liquid and solid phases is flat. We consider the side walls and the bottom to be thermally insulated and perfectly rigid. We derived analytical expressions for determining the pressure


Author(s):  
Shamil Gasanguseinovich Magomedov

The paper focuses on the formation of general schemes describing access to protected information or other resources, and, thereby, the boundaries of countering real and potential threats to these resources. Three main access environments are considered: information, physical and electromagnetic. For the first two, as for the most important, the main access points are highlighted. Nine boundaries are distinguished for the information environment, and seven boundaries for the physical environment. Dedicated boundaries encompass both the external perimeter of the protection object and the internal zone of the object, as well as the data carriers. On the basis of the analysis of the content of the allocated access boundaries, a list of information security functions that are needed at each access boundary and in the protection system as a whole has been formed. This list includes more than thirty basic functions and technological procedures. The presence of this list is one of the foundations for the formation of an integrated information security system that provides multi-level safety of protected information resources.


2018 ◽  
Vol 31 ◽  
pp. 07002 ◽  
Author(s):  
Juang Akbardin ◽  
Danang Parikesit ◽  
Bambang Riyanto ◽  
Agus Taufik Mulyono

The poultry commodity consumption and requirement is one of the main commodities that must be fulfilled in a region to maintain the availability of meat from poultry. Poultry commodity production is one of the production sectors that have a clean environment resistance. An increasing of poultry commodity generation production requires a smooth distribution to arrive at the processing. The livestock location as a commodity production is placed at a considerable far distance from residential and market locations. Zones that have poultry commodity production have an excess potential to supply other zones that are lacking in production to the consumption of these commodities. The condition of highway transportation infrastructure that is very diverse with the damage level availability in a zone has an influence in the supply and demand of poultry commodity requirement in the regional internal of Central Java province. In order to know the effect of highway transportation infrastructure condition toward the poultry commodity movement, demography factor and availability of freight vehicles will be reviewed to estimate the amount of poultry commodity movement generation production. Thus the poultry commodity consumption requirement that located in the internal - regional zone of central java province can be adequated from the zone. So it can be minimized the negative impacts that affect the environment at the zone in terms of comparison of the movement attraction and generation production at poultry commodity in Central Java.


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