shaping process
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Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Victoire Lescure ◽  
Morgane Gelin ◽  
Mélanie François ◽  
Mohammad Arab Pour Yazdi ◽  
Pascal Briois ◽  
...  

New advanced fuel cell technologies are moving towards high-temperature proton conductors (HTPCs) to meet environmental issues. Their elaboration remains a challenge and micro-computed tomography (µCT) is an innovative way to control their quality. NiO-BZY anodic supports of a protonic ceramic electrochemical cell (PCEC), elaborated by co-tape casting and co-sintered at 1350 °C, were coated with a BZY20 electrolyte layer by DC magnetron sputtering. The µCT allowed to observe defects inside the volume of these PCEC half-cells and to show their evolution after an annealing treatment at 1000 °C and reduction under hydrogen. This technique consists in obtaining a 3D reconstruction of all the cross-sectional images of the whole sample, slice by slice. This allows seeing inside the sample at any desired depth. The resolution of 0.35 µm is perfectly adapted to this type of problem considering the thickness of the different layers of the sample and the size of the defects. Defects were detected, and their interpretation was possible thanks to the 3D view, such as the phenomenon of NiO grain enlargement explaining defects in the electrolyte, the effect of NiO reduction, and finally, some anomalies due to the shaping process. Ways to anticipate these defects were then proposed.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 351
Author(s):  
Lennart Waalkes ◽  
Jan Längerich ◽  
Philipp Imgrund ◽  
Claus Emmelmann

Piston-based material extrusion enables cost savings for metal injection molding users when it is utilized as a complementary shaping process for green parts in small batch sizes. This, however, requires the use of series feedstock and the production of sufficiently dense green parts in order to ensure metal injection molding-like material properties. In this paper, a methodological approach is presented to identify material-specific process parameters for an industrially used Ti-6Al-4V metal injection molding feedstock based on the extrusion force. It was found that for an optimum extrusion temperature of 95 °C and printing speed of 8 mm/s an extrusion force of 1300 N ensures high-density green parts without under-extrusion. The resulting sintered part properties exhibit values comparable to metal injection molding in terms of part density (max. 99.1%) and tensile properties (max. yield strength: 933 MPa, max. ultimate tensile strength: 1000 MPa, max. elongation at break: 18.5%) depending on the selected build orientation. Thus, a complementary use could be demonstrated in principle for the Ti-6Al-4V feedstock.


2021 ◽  
Vol XII (2) ◽  
pp. 235-246
Author(s):  
Alise Gunarssonne ◽  
◽  
Baiba Dumpe ◽  
Vanda Visocka ◽  
Artūrs Brēķis ◽  
...  

Latvia in the 11th–13th century poses a curious case for the coexistence of two different practices of Baltic ware production. The Baltic ware pots from lower reaches of the River Daugava and from the Courland region look not just stylistically, but also technologically different. Our paper assessed the production traces by using macro-observations, Reflectance Transformation Imaging (RTI) and extensive ethnographic material of Slavic pottery production of the 1900s, as well as using modern replicas as visual aids to assist in the identification of the principal coil attachment methods. The results showed that potters from the lower reaches of Daugava used the wheel’s rotation extensively during the shaping process of Baltic ware. The production of the pots required the potter to possess a level of technical skill which implied a level of professionalisation. Baltic ware from Courland was less technically complicated and used comparatively more of the methods of handmade pottery production.


Author(s):  
Alexander Leshchenko

The accuracy of processing surfaces of a complex profile largely depends on the selected processing strategy, which will allow creating the same, within certain limits, power characteristics of the shaping process at the intervals of the programmed tool path. In this case, it becomes possible to include tuning modules in programs for CNC machines that form vector values of corrections in certain areas, as reactors for elastic deformations of the cutting process. Therefore, it is especially important to know the modulus and direction of the resulting cutting force vector, which does not necessarily coincide with the feed direction. The purpose of this work is to build a method for calculating cutting forces by modeling the geometric parameters of a cut with a CAD system, a cutter with a nonlinear generatrix. Solid modeling of the process is based on the Boolean operations of "intersection" and "subtraction" of 3D objects: the teeth of a radius cutter with a helical cutting edge and a workpiece "moving" at a feed rate. The tool for the implementation of this method is a software module created on the basis of API functions, the input data for which are: a 3D tool and a workpiece, the equation of the trajectory of its movement and the parameters of the infeed movement. Targeting API properties, the application makes it possible to simulate various trajectories, helical or trochoidal, when machining complex surfaces. In the future, it is possible to take into account the plastic deformation processes in the chip formation zone in the model by connecting external modules. In the course of the conducted research on milling with radial end mills with a helical cutting edge, when two or more teeth are within the arc of contact, it was determined by 3D modeling how much thickness and width the layer cuts off each of the teeth during the feed per revolution. Consequently, in the process of shaping, normal and tangential cutting forces, which are different in direction and modulus, are present as a function of the angle of rotation of the cutter. Therefore, the concept of "circumferential force on the cutter", accepted in the theory of cutting, as a certain constant component of the process, can introduce an error when considering the causes of the excitation mechanism of vibrations of different nature that arise in the processing zone.


Author(s):  
A.V. Akintseva ◽  
◽  
P.P. Pereverzev ◽  
A.S. Degtyareva-Kashutina ◽  
◽  
...  

AMS Review ◽  
2021 ◽  
Author(s):  
Alexander Flaig ◽  
Daniel Kindström ◽  
Mikael Ottosson

AbstractThis study explores the potential existence of reoccurring patterns in market-shaping processes by employing a qualitative meta-analysis to analyze 79 case studies on market-shaping. Through the evidence-based synthesis of qualitative data, we extract 20 generalized market-shaping activities that inform and form the foundation of a three-phased market-shaping process. This conceptual framework divides the market-shaping process into the phases of infusion, formation and retention. By applying our conceptual framework to the qualitative dataset, we explore the presence of market-shaping phases and provide further insights into the interdependences and dynamics between multiple, simultaneously occurring, market-shaping processes. By providing a structured market-shaping process, we attempt to reduce the overall complexity of the market-shaping phenomenon and facilitate the operationalization of the phenomenon for further market-shaping research. Additionally, our conceptualization provides practitioners with a framework to analyze the market-shaping efforts of other market actors and support the design of their own market-shaping strategies.


2021 ◽  
Vol 11 (12) ◽  
pp. 1662-1667
Author(s):  
Ying Fang

The paper aims to interpret Arthur Miller’s stream-of-consciousness play text, After the Fall, from the perspective of the cognitive concept of evolving reference, namely “role and values”. The results of the study are as follows: 1. Mutual across-time-and-space contextual embedment or entanglement is the distinctive feature of stream-of-consciousness play text, which makes it possible to present synchronically what has happened diachronically, so that the various values generated by role switching over the past years are accessible in a while. 2. This feature in turn makes characterization more natural, true-to-life, vivid and substantial, revealing not only the different aspects of the protagonist’s disposition but also the shaping process involved. 3. Despite the seemingly disordered contextual entanglement, the values through role switching are implicitly linked by the cause-effect logical relationship, which ensures the textual coherence of the play.


Geology ◽  
2021 ◽  
Author(s):  
Adrian M. Bender

Bedrock river-gorge incision represents a fundamental landscape-shaping process, but a dearth of observational data at >10 yr timescales impedes understanding of gorge formation. I quantify 102 yr rates and processes of gorge incision using historical records, field observations, and topographic and image analysis of a human-caused bedrock meander cutoff along the North Fork Fortymile River in Alaska (USA). Miners cut off the meander in 1900 CE, abruptly lowering local base level by 6 m and forcing narrowing and steepening of the channel across a knickpoint that rapidly incised upstream. Tectonic quiescence, consistent rock erosivity, and low millennial erosion rates provide ideal boundary conditions for this 102 yr gorge-formation experiment. Initial fast knickpoint propagation (23 m/yr; 1900–1903 CE) slowed (4 m/yr; 1903–1981 CE) to diffusion (1981–2019 CE) as knickpoint slope decreased, yielding an ~350-m-long, 6-m-deep gorge within the pre–1900 CE channel. Today, diffusion dominates incision of a 500-m-long knickzone upstream of the gorge, where sediment transport likely limits ongoing adjustments to the anthropogenic cutoff. Results elucidate channel width, slope, discharge, and sediment dynamics consistent with a gradual transition from detachment- to transport-limited incision in fluvial adjustment to local base-level lowering.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5434
Author(s):  
Florentino Alvarez-Antolin ◽  
Laura Francos-Garrote ◽  
Alejandro Gonzalez-Pociño ◽  
Alberto Cofiño-Villar

The lids of glass containers which have a ‘twist-off’ mechanism are manufactured from tinplate through a process of cutting and drawing. Previously, the tinplate was protected with a double layer of a certain epoxy-phenolic varnish. During cutting, the detachment of threads of varnish is produced, and these may reach more than 150 microns in diameter. These threads stick to the equipment, thus hindering the shaping process. After manufacturing thousands of lids, stops must inevitably be made in production in order to clean machinery. Through the application of a fractioned design of experiment (DoE) application, carried out on an industrial scale, the effect of a number of factors on the detachment of threads of varnish was studied. Some to these factors refer to coating, others to the substratum and others to the process of cutting and drawing. It is concluded that the detachment is greater in the disk areas which are parallel to the forward direction of the production line. This problem could be substantially reduced, and even eliminated, if the direction of the rolling of the sheet metal were perpendicular to that of the forward direction of the production line, if the blank-holder is situated at 4 bar, if the time between the curing process and cutting is no more than 3threedays, if the clearance in the cutting is situated at 0.06 mm, and if the grammage of the varnish and the grammage of the layer of tin are increased.


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