bluuebunny/crossref_metadata_2025 huggingface dataset:
Research into percolation leaching of copper and silver from aged tailings
Authors: Karimova L. M. , Kairalapov Ye. T. , Mansurov B. E.
Published: April 2023

This paper investigates the extraction of silver by percolation leaching of a pelletized sample of aged tailings with organic binder Alcotac® CB6. Laboratory studies of percolation leaching were conducted using a column with a height of 0.5 m and an internal diameter of 56 mm. Pelletization was performed in a drum-type pelletizer with the consumption of Alcotac® CB6 (BASF, Germany) of 800 g/t and the pellet moisture content of 8–10% and size of 8–10 mm. The sample composition was analyzed taking into account the data obtained by optical tests, electron microscopy, X-ray diffraction, local X-ray spectrometry, X-ray fluorescence analysis, and inductively coupled plasma mass spectrometry. The research object was aged tailings of the Zhezkazgan processing plant (Ulytau region, the Republic of Kazakhstan), where copper is mostly represented by oxidized minerals (78.47%) and sulfide minerals (21.53%). The results of physical and chemical analyses conducted to determine the material composition of samples are presented, along with observations over percolation leaching of copper and silver from Zhezkazgan aged tailings. The copper leaching studies included two stages using a sulfuric acid solution as a solvent. The subsequent stage was silver dissolution by cyanide leaching. Copper extraction into the solution comprised 88.55% with a sulfuric acid consumption of 80.0 kg/t; silver extraction comprised 75.31% with a sodium cyanide consumption of 0.55 kg/t. The conducted studies showed the efficiency of using Alcotac® CB6 for percolation leaching of pre-pelletized aged tailings. During leaching, the pelletized material exhibits sufficient porosity and permeability, thus providing access of cyanic solutions to the surface of precious metals.
Analysis and improvement of methods for calculating the resistance of substation earthing equipment
Authors: Lyakhomskiy A. V. , Kuzmin S. V. , Kudryashov A. P. , Kuzmin R. S. , Kuzmin I. S. , Menshikov V. A.
Published: April 2023

In this study, we analyze the results of calculating the resistance of substation earthing equipment taking operational factors into account. The resistance of a substation earthing system was estimated using both calculation (methods of equipment operating factors, generalized parameters and induced potentials) and instrumental (ammeter-voltmeter) methods. During operation, the resistance of the studied earthing system was found to increase in comparison with the rated values, thus reducing its overall efficiency. The resistance of substation earthing equipment measured experimentally by the ammeter-voltmeter method showed the relative error of the considered calculation methods to reach 48, 46.7 and 28.6%, respectively. With the purpose of increasing the calculation accuracy of earthing equipment resistance by the method of induced potentials, it was proposed to use an operating factor. Thus, during the substation operation period of 10, 10–20 and over 20 years, the resistance of the earthing system increases by 1.02–1.1 times due to corrosion. It was shown that the installation procedure and maintenance checks (conducted at least every six years) increase the resistance of earthing systems by 1.02 and 1.05 times, respectively. Lightning discharges and short-circuit currents affect the corrosion rate of earthing systems, thereby increasing their resistance by 1.01–1.03 and 1.03–1.05 times, respectively. Therefore, the operating factor value may range from 1.115 to 1.274. The use of the operating factor in calculating the resistance of an earthing system by the induced potentials method increased the overall calculation accuracy, with the relative error not exceeding 3%. This corresponds to the normative and technical requirements stipulated by the Federal Grid Company of the Unified Energy System of Russia.
The texture of non-fat yogurt with proteins isolates and concentrates
Authors: Gurskiy I. A.
Published: April 2023

Yogurt is one of the most common fermented milk products. It is consumed directly as food or used for the production of fermented milk desserts and ice cream. The urgent task for yogurt producers is improving product quality due to additionally introduced protein components. In this study, an effect of protein isolates and concentrates on the rheological parameters of yogurt was evaluated. The methods included the determination of dynamic viscosity and texture indices, such as hardness, gumminess, chewiness, springiness, cohesiveness and adhesiveness. The prepared yogurt samples were investigated immediately and after 30 days of storage at a temperature of 4±2°C. The water-holding capacity was evaluated. It has been established that introduction of whey proteins makes it possible to increase the water-holding capacity to 77% and 80%, respectively. The highest value of dynamic viscosity (19.3 and 26.1 Pa·s) was found in the samples with isolate and concentrate of native whey proteins after 5 hours of fermentation. A decrease in dynamic viscosity with the introduction of milk protein isolate, soy protein concentrate and native whey protein isolate was observed after 5 hours of fermentation. Addition of the protein components led to a significant increase in texture indices, except for cohesiveness. The highest cohesiveness value of 0.4 N·s was found in the sample without protein components and in the sample with whey protein concentrate. The indicators of hardness, gumminess, chewiness, springiness and adhesiveness were the highest in the sample with native whey protein isolate.
Elää, kokea, ymmärtää. Alex Matsonin elämä
Authors: Varpio Yrjö
Published: April 2023

Live, Experience, Understand. The Life of Alex Matson Alex Matson (1888–1972) is an important Finnish literary critic and essayist, whose literary reviews and collections of essays have made a vital contribution to the development of Finland's postwar literary generation. Born in Finland as the son of a sailor, Matson moved as a young child with his family to Hull in England, where he went to school. In the 1910s, he moved back to Finland, where he at first established himself as painter associated with the expressionist November Group, an important Finnish artistic movement at the time. In the interbellum, he moved from fine arts to literature. In the 1920s and 1930s, he published several novels, but more important was his work as transmitter of international literary ideas to Finland. Together with his first wife, Kersti Bergroth, he edited the literary journal Sininen kirja ("The Blue Book"; 1927–1930), which was inspired by the writings of John Middleton Murry and Katherine Mansfield. Sininen kirja is the most international literary journal in Finnish history to date and introduced Finland to the most significant modernist writers of the first half of the 20th century (Gottfried Benn, Jean Cocteau, Alfred Döblin, T. S. Eliot, Aldous Huxley, James Joyce, D. H. Lawrence, Katherine Mansfield, Paul Valéry, Virginia Woolf). During the Second World War, Matson worked for the State Communications Agency, which was responsible for disseminating relevant information about Finland to other nations and for informing Finns of relevant developments abroad. It was also tasked with studying the prevailing mood among the population in Finland. In Matson's unpublished wartime diaries, one can see the first symptoms of a shift in Finnish culture away from Germany and towards Anglo-Saxon culture. From the 1940s onwards, Matson recommended new English and American novels as a part of his work as reader for Finnish publishing houses, and he also translated works by Joyce, Hemingway and Steinbeck. With the help of a network of international literary critics, Matson became acquainted with New Criticism, which he introduced to Finland before it became established among academic researchers. He was often critical of academic literary studies, but his seminal essay works Romaanitaide ("On the Prose Novel"; 1947), John Steinbeck (1948), Kaksi mestaria ("Two Masters", on Tolstoy and Dostoevsky; 1950) as well as his impressive conversational skills were instrumental in introducing knowledge about the principles of the prose novel to several authors (including Väinö Linna, Lauri Viita, and Hannu Salama), and contributed to their views of literature. Matson emphasized the importance of reading and understanding high-quality literature for the wellbeing of society.
Ether cleavage and chemical removal of SU-8
Authors: Ripalda José M. , Álvaro Raquel , Dotor María Luisa
Published: April 2023

The high chemical stability of SU-8 makes it irreplaceable for a wide range of applications, most notably as a lithography photoresist for micro and nanotechnology. This advantage becomes a problem when there is a need to remove SU-8 from the fabricated devices. Researchers have been struggling for two decades with this problem, and although a number of partial solutions have been found, this difficulty has limited the applications of SU-8. Here we demonstrate a fast, reproducible, and comparatively gentle method to chemically remove SU-8 photoresist. An ether cleavage mechanism for the observed reaction is proposed, and the hypothesis is tested with ab initio quantum chemical calculations. We also describe a complementary removal method based on atomic hydrogen inductively coupled plasma.
Unmanned Maritime Vehicles in Indonesia for Cargo Shipping
Authors:   International Business Law, Universitas Prasetiya Mulya BSD City Kavling EdutownI.1, Jl. BSD Raya Utama No.1, BSD City, Kec. Pagedangan, Kabupaten Tangerang, Banten 15339, Mugito Bryan
Published: April 2023

Through technological developments, Indonesia has launched an Unmanned Marine Vehicle during a test. Definitions of Unmanned Marine Vehicles in the eye of the international law community is a controversial topic with an unending discussion. There are uncertainties where safety measures may hinder progress and economic potential when not treated correctly. To accommodate the technological developments, changes in norms and regulations regarding definition of a ship must be done to give medium for technological developments and provide legal certainty towards Unmanned Marine Vehicles in Indonesia that deliver cargo. This development is a cornerstone for commercial enterprises to gain capabilities and efficiency in delivering their goods with the latest technology which creates an urgency to stryfe for its existence in Indonesia.
Governo Cardoso (1995-2002) e Governo Lula (2003-2010)
Authors: Jardim Maria Chaves , Rosa Tiago
Published: April 2023

Os governos Cardoso (1995-2002) e Lula (2003-2010) constituem momentos marcantes da história social, política e econômica contemporânea do Brasil. O artigo busca explorar o tema, a partir do estudo da biografia de 151 ministros que atuaram entre 1994 e 2010 nas pastas titulares. Após apresentar uma cartografia do perfil de todos os ministros, por meio de diversas variáveis, o artigo dá destaque paratrês delas: ocupação dos pais e avós dos ministros, universidade pelas quais passaram e a circulação internacional desses. Buscamos identificar se existe homologia entre a trajetória individual dos ministros eas crenças econômicas vigentes do período. Inspira-se na sociologia de P. Bourdieu e faz uso da Prosopografia. Os resultados indicam existir homologia entre as trajetórias individuais dos ministros e as crenças econômicas vigentes do período, expressa, sobretudo, a partir de crenças neoliberais ou desenvolvimentistas, divulgadas nas universidades pelas quais passaram, em formato de teoria econômica.
A Degradação e a Autenticidade do Trabalho: experiências e significados desiguais nas classes populares e médias
Authors: Fernandes Freire Alyson Thiago , Carlos Eduardo Freitas
Published: April 2023

Este artigo deriva da pesquisa empírica “Radiografia do Brasil contemporâneo”, realizada entre os anos de 2015 e 2016 junto ao Instituto de Pesquisa Econômica Aplicada (IPEA). Abordamos a desigualdade entreas classes sociais a partir da problematização do modo como essas vivenciam e se relacionam subjetivamente em seu cotidiano e ao longo de suas biografias com o mundo do trabalho. Por meio de entrevistas em profundidade com indivíduos das classes populares e também com integrantes das classes médias, discutimos como as experiências vividas e significados atribuídos ao trabalho apresentam conteúdos contrastantes e profundamente desiguais quanto às formas de inserção, sentido, trajetória e identidade. Sustentamos, no artigo, a tese segunda a qual a esfera do trabalho brasileira se caracteriza, em grande medida, como um domínio de rotinização de experiências de não-reconhecimento, violência e desclassificação social contra as frações mais destituídas das classes populares.
Apresentação do Dossiê
Authors: Rodrigues Fernando , Candotti Fabio Magalhães , Biondi Karina , Paiva Luiz Fábio S.
Published: April 2023

Apresentação do Dossiê
Using the Indicator ‘Economiic Level of Technology’ in Managing Industrial and Technological Systems in Consumer Goods Industry
Authors: Khrulkov D. V.
Published: April 2023

The article studies issues of assessing efficiency of production and technological systems (enterprises) in consumer goods industry. Sanction restrictions built new challenges for customer goods industry but at the same time opened new opportunities. The drawback of the current approaches to managing enterprises of customer goods industry is the absence of dynamic appraisal of the technological process quality, which can cause a delayed response to crisis phenomena. To provide efficient management it is proposed to use the indicator ‘economic level of technology’ (ELT) that implies complex assessment of quality and efficiency of the production and technological system. Advantages of this indicator include possibility to forecast the development of production on the basis of due regard to laws of technological process development. With the help of calculations illustrated by two enterprises of microlevel, i.e. the transnational company Nike and the Russian company Dochki Synochki, as well as the US macroeconomic system it was proved that this indicator of efficiency can forecast arising of crucial trends in operational work of the enterprise and economy in general. Taking into account problems facing enterprises of customer goods industry ELT indicator could be used to raise effectiveness of managerial decision-making on the enterprise level and industry and state level in view of target support of development.
Molecular Docking, Acute Toxicity and Antibacterial Study of Debilon and Phorbasterone-B Extracted from Rhodophyta
Authors: Salman Saad , Shah Fahad Hassan , Shah Mehwish , Kim Song Ja
Published: April 2023

Introduction:

Natural compounds obtained from marine algae, especially Rhodophyta are now
being investigated for various biological activities. However, the antimicrobial activity and toxicity profile
of compounds present in these algae isunderexplored.

Objective:

This study procured two compounds, Debilon and Phorbasterone-B, from Rhodophyta to analyze
their in silico and in vitro potential against pathogenic bacterial strains and their acute toxicity.

Methods:

Debilon and Phorbasterone-B were extracted from Rhodophyta by a previously reported method
and were further subsequently exploited computationally for their physicochemical properties, prediction
of biological activity and molecular docking against bacterial proteins, toxicity, and experimentally
for antibacterial potential against pathogenic strains of Vibrio cholera, Salmonella typhi, Escherichia coli,
Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa.

Results:

Docking studies proved that these molecules possess a chemical affinity for the bacterial proteins
and can inhibit the growth of these microorganisms, as confirmed by antibacterial assay. Whereas the
prediction analysis and toxicity studies showed that the friendliness of these molecules to the human body
is enormous.

Conclusion:

From this study, it has been proved that DN and PB are perfect candidates for inhibiting
these bacterial strains.
Assessment of Wound Healing Potential of Simvastatin Emulgel in Rat
Excision Wound Model
Authors: Gupta Surbhi , Anand Anubhav , Gupta Ramesh Kumar
Published: April 2023

Background:

Microorganisms can infect wounds and disrupt healing by causing inflammation
and tissue injury

Objective:

Simvastatin (SIM) is reported to have antibacterial activity; therefore, this research is designed
to evaluate the efficacy of simvastatin emulgel in wound healing.

Methods:

The simvastatin emulgel was assessed for physical appearance, rheological behaviour, spreadability,
pH, ex vivo drug release and in vivo activity. The wound-healing activity was assessed by percent
wound contraction, hydroxyproline estimation and histopathological evidence in wound-induced albino
rats.

Results:

The simvastatin emulgel exhibited viscosity and spreadability of 6875 ± 531.21 mPa.s and 10.15
± 0.31 g.cm/sec, respectively. The simvastatin emulgel exhibited wound contraction in wound healing
studies compared to the reference product (p < 0.05). This activity was statistically significant (p < 0.05)
in comparison to the control. The hydroxyproline content supported the wound-healing promoting effect
of simvastatin emulgel, and marked improvements in the skin histological architecture were seen in the
histopathological study.

Conclusion:

The study manifested the promising potential of simvastatin emulgel in speeding the healing
of rat wounds with epithelization. Therefore, the designed simvastatin emulgel can be used as an option
for the conventional topical dosage form.
On the comparison of heterogeneous mechanical tests for sheet metal characterization
Authors: GONÇALVES M.
Published: April 2023

Abstract. The characterization of sheet metal behavior is of utmost importance for the accurate virtualization of sheet metal forming processes. Newly proposed mechanical testing approaches are overcoming the use of standard mechanical tests. Test configurations with more complex geometries present richer mechanical fields and, therefore, provide a higher quantity of valuable information about the material behavior in a more efficient manner. To extract that information, full-field measurement techniques such as Digital Image Correlation are being used. Although several test designs have already been proposed, the choice of the best one to calibrate a chosen mechanical model is still an issue. This work aims at proposing Key Performance Indicators (KPIs) that are able to rank mechanical tests by their potential to enhance the material behavior characterization process. These metrics evaluate quantitatively the quality and the importance of the data that each test can provide. The potential of three test designs to characterize accurately sheet metal mechanical behavior is analyzed using the proposed KPIs. From a uniaxial tensile loading test up to rupture, the numerical mechanical information is extracted, and the performance of each test is evaluated and compared.
On the inverse identification of sheet metal mechanical behaviour using a heterogeneous Arcan virtual experiment
Authors: HENRIQUES J.
Published: April 2023

Abstract. Modelling and simulation are critical stages of product development in modern industry. Simulation tools in solid mechanics use constitutive models and their parameters to describe the behaviour of materials. Nowadays, with the use of heterogeneous test configurations and full-field measurements, it is possible to measure a combination of multiple strain states, allowing for the identification of multiple parameters from a single test with reduced cost and time. This work aims to investigate the potential for obtaining heterogeneous states of strain\stress with the Arcan test configuration. A finite element model was developed using a specimen with a smooth arc section in which the loading and material directions varied, producing tensile, shear, or mixed mode responses. The most heterogeneous test configuration was selected using a heterogeneous criterion and the numerical results were used to generate synthetic speckle pattern images and further processed by digital image correlation (DIC). The DIC results were used as input for the identification procedure through the virtual fields method (VFM) for the simultaneous calibration of the Swift hardening law and the Hill'48 anisotropic yield criterion. The identified solution was compared with the ground truth material parameters. The results show the potential of combining the Arcan test with the VFM to simultaneously identify material parameters for anisotropic plasticity models of sheet metals.
Manufacturing of graded grinding wheels for flute grinding
Authors: DENKENA B.
Published: April 2023

Abstract. In this paper, two different methods for manufacturing of graded grinding wheels for two different metal bonds are presented. One method is based on the use of a mask and manual moulding and the other on a height-adjustable holder for moulding. For this purpose, a brittle and a ductile bronze bond are compared. The graded grinding wheels are fabricated through sintering with Field Assisted Sintering Technology (FAST). An analysis of the grain distribution is used to demonstrate the reproducibility of the manufacturing methodology. For analysis, light microscope images of cross-sections of the abrasive layers are taken. The grain distribution is determined using image processing software and a greyscale method. Finally, the advantages of each method are compared. As a result, both manufacturing methods are evaluated in terms of precision, feasibility and efficiency. From this, a recommendation on the implementation and further development of the methods is derived. This method enables the manufacturing of graded grinding wheels for an effective reduction of wear differences for grinding cemented carbide end mill cutters.
Influence of process parameters and head orientation on bead geometry for coaxial wire laser additive manufacturing
Authors: ROCH C.
Published: April 2023

Abstract. Among Directed Energy Deposition (DED) processes for metallic materials, Wire Laser Additive Manufacturing (WLAM), distinguishes itself by the use of a laser beam to melt a metallic wire and produce beads. Successive depositions of overlapping beads generate volumes to obtain parts. Thus, controlling bead geometries is essential for the additive manufacturing process. Several research works have studied these geometries and the influence of the main manufacturing parameters on their dimensions, but few investigated the effect of feeding direction or wire angle. Moreover, all studies on wire angle were carried out with lateral feeding and a constant laser orientation. This paper focuses on the influence of the deposition head orientation for a coaxial wire feed with 3 laser beams on bead geometries. An experimental campaign is conducted with different orientations relatively to a horizontal substrate and the external profiles are measured using optical instruments in order to extract the average profiles and characteristic dimensions. Results indicate an influence of the head rotation around its axis and lateral tilt on the height, width, and asymmetry of the beads.
Superfinishing processes applied on the biomedical implants surface to improve their performance
Authors: Saffioti M.S.
Published: April 2023

Abstract. The demand of biomedical implants characterized by more and more advanced performances is expected to grow as well as their service life is expected to increase. Therefore, the necessity to research new material properties and production techniques in producing biomedical implants, characterized by higher durability, is strongly required. Regarding permanent prosthesis, the surface conditions play a key role on the prostheses overall mechanical performance. This work aims, through the application of burnishing process, to combine innovative machining finishing operations coupled with environmentally friendly lubricooling techniques to improve the surface integrity of biomedical devices in order to increase their quality, durability and reliability.
Investigation of machining performance of lead-free brass materials forged in different conditions after cooling with liquid nitrogen
Authors: ATAY G.
Published: April 2023

Abstract. The forging process, which is one of the hot forming methods, is used to produce plumbing systems, valves, batteries, fittings, condensers, pipes, etc. from brass alloys in duplex structures. Compared to leaded brasses, machining becomes very difficult due to reasons such as long and continuous chips, burrs, built-up edge in the tool, and unacceptable surface quality problems. In this study, studies have been carried out to improve the machining process that minimizes the mentioned machining problems by controlling the microstructural of lead-free brass materials. Therefore, by examining the effect of the copper content of the forged material, forging temperature, the cryogenic cooling method input parameters after forging on the phase ratio of the material, investigations were carried out on obtaining a high-performance machining process close to the machinability performance of leaded brass materials with good chip breakability. The change in the distribution of beta phases in the material after forging was investigated and machining tests were performed as a hole drilling operation. Cutting forces, surface roughness, and dimensional accuracy analyzes were evaluated within this purpose. The relationship between the beta phase ratio in the material and the machinability has been revealed and it has been observed that the CW511L alloy produced in three different ratios in the standard range and although they are the same material, the Cu% ratio causes significant changes in terms of machinability.
Suitability evaluation of pre-formed cruciform sample without thickness reduction for high strain values in the center of the specimen under different strains paths
Authors: MITUKIEWICZ G.
Published: April 2023

Abstract. In this study, the Finite Element (FE) simulation of an initially pre-deformed DC-5 steel cruciform specimen has been carried out and compared to experimental results. A new geometry of the sample with local reinforcements and without thickness reduction allows distribution of plastic deformation and gets high strains in its gauge region. The simulation is divided into two steps. The first one introduces initial deformation to the sample arms. For the second step, the calculated strain field is introduced as an initial pre-strain field before the application of loading along the two perpendicular arms of the cruciform specimen during the in-plane biaxial tensile test. The described numerical study expands the knowledge of material plastic flow using a ductile damage criterion under different biaxial tensile strain paths. The numerical and experimental results are in good agreement for different strain paths, from uniaxial to equibiaxial strain states.
Examination of intrinsic and extrinsic size effect in thin specimens through crystal plasticity frameworks
Authors: GÜNAY E.
Published: April 2023

Abstract. Manufacturing devices at the microscale requires a precise analysis for desirable mechanical behavior. As the products of microscale forming operations have a comparable thickness dimension with grain size, the ratio between thickness and grain size (t/d) becomes an important aspect of mechanical behavior. A number of experimental studies investigated this phenomenon and have shown the influence of the t/d ratio in micron-sized sheet specimens. On the other hand, the computational studies addressing this phenomenon employing micromechanics-based models are quite restricted. The current study aims to investigate the t/d ratio effect through finite element method (FEM) simulations with both local and nonlocal crystal plasticity frameworks. The numerical analyses with the local crystal plasticity framework are obtained by utilizing two different methodologies, where the initial slip resistance is taken as constant or modified using a subroutine based on grain size effects and slip system interactions (see [1]).
Combined material model to predict flow curves of cold forging raw materials having high strain hardening exponent
Authors: ZEREN D.
Published: April 2023

Abstract. In order to increase the accuracy of cold forging simulations, flow curves obtained by experimental compression tests are used instead of the material models existing in the software library. The parameters of Ludwik material model were determined with respect to the constructed experimental flow curves at different temperatures and strain rates. Then, the flow curves were defined into the software by using these parameters. While Ludwik model can represent the material flow curve with high accuracy at low plastic strain values, the error rate between the experimental flow curve and the Ludwik model increases at high plastic strain values. Voce material models were known to predict the flow curve of materials with high strain hardening exponents more accurately, especially at high temperature and strain values. In this study, the performance of Ludwik material model was compared to four Voce material models given in the literature and a more accurate combined material model was defined for each flow curve at different temperature and strain rates for 42CrMoS4 material. All experimental flow curves were predicted with a minimum R2 of 0.99 and the lowest mean absolute error value with the new combined material model.
Digital twin development for the sensitivity analysis of near solidus forming process
Authors: MUHAMMAD S.
Published: April 2023

Abstract. Near Solidus Forming (NSF) process, performed at semi-solid material state is gaining popularity due to its good physical properties, low manufacturing cost and material waste. Although the process possesses many advantages over traditional hot forging, the nature of the process itself is very complex and due to this the researcher struggles to identify the material behavior at NSF conditions. Especially the material model in this condition has not been stated clearly before and therefore it is important to develop a reliable digital twin (DT) strategy which can validate the material model efficiently. Therefore, the objective of this work is to investigate the influence of all DT parameters like billet material and dimensions, billet and dies temperature, heat transfer coefficient, emissivity, ambient temperature, and friction coefficient, in two industrial components such as H spindle and R spindle. The Taguchi Design of Experiments (DOE) approach combined with numerical simulation in FORGE NxT® is employed to develop the sensitivity analysis of the process. The impact of all parameters in the DT are evaluated in terms of die filling and forming forces, and its importance in the material model is studied. Results show that the newly developed approach proposed a novel optimum NSF-DT calibration strategy for material-model validation. Which can be used to develop an accurate model of the NSF process at the laboratory and industrial scale
Application of the plane-strain-compression-test to determine the local mechanical properties of LPBF-manufactured 316l components
Authors: JENSCH F.
Published: April 2023

Abstract. In the Laser Powder Bed Fusion (LPBF) process for metal components, a CAD file is sliced into layers with a thickness of 20-80 micrometers and the component is built up layer by layer. For this purpose, a metal powder layer is applied in each case and melted locally. This process is repeated until the geometry is completely established. The mechanical properties of the manufactured part are controlled by the cooling rate. It is currently not considered in the design of LPBF components, that the printed part has a varying heat flow into the surrounding powder and into the support plate depending on its slenderness. As a result of the different temperature histories, different microstructures with correspondingly different mechanical properties are formed in the untreated state (as-built). These differences must be considered in the component design. In this work, walls of various thicknesses were produced from 316L stainless-steel alloy using the LPBF process. The walls could be used to create plane-strain-compression-test specimens of various heights and orientations. The tests were performed according to Graf et al. [1] and the flow curve was calculated from the force-displacement curve while taking friction into account. Following that, tensile strength, Young’s modulus, yield strength, and yield stress were determined inversely. A clear dependence of the mechanical parameters on the degree of slimness was discovered, which was confirmed by microscopic examinations. To summarize, the plane-strain-compression-test is a quick and reliable method for determining the local variation of mechanical properties.
Analysis of the relationship between the properties of selected materials and the parameters of the EDD process
Authors: TRAJER M.
Published: April 2023

Abstract. The thermophysical properties of the electrodes material significantly impact performance of the electrical discharge machining (EDM). The aim of this article was to investigate the influence of thermophysical properties of selected materials on the EDM process. The effect of the thermophysical properties of these materials on process efficiency factors (material removal rate, linear tool wear) and hole geometry (aspect ratio, radial overcut) was analyzed. The results showed that selected thermophysical properties of the workpiece, such as thermal conductivity, melting point, have the most significant impact on the electro-erosion process. Optimal result parameters (material removal rate: 2.58 mm3/min, linear tool wear: 4.95 mm, aspect ratio: 8.00, radial overcut: 0.046 mm) and no presence of “bottom cone” were obtained for EDM drilling in Inconel 718 and similarly for AISI 1045 steel. On the other end were high resistance alloys such as tungsten carbide and copper alloy.
Resources and manufacturing technology evaluation of hybrid additive metal laminated tooling for forming
Authors: DARDAEI JOGHAN H.
Published: April 2023

Abstract. The rough surface finish caused by the stair step effect is the major drawback in the application of sheet metal laminates in rapid tooling. The application of laser metal deposition (LMD) and subsequent post-processing (milling, ball burnishing, and laser polishing) to reduce the stair-step effect in hybrid additive metal laminated forming tools was recently presented. In the present study, the energy consumption and manufacturing time of the hybrid process are compared with the conventional (milling plus hardening by heat treatment) as well as with full LMD and milled components. The hybrid process requires significantly less energy and manufacturing time compared to the LMD components. Since the surface hardness is sufficient for tooling in the hybrid process, no additional hardening is required, also resulting in a shorter manufacturing time and lower energy relative to the conventional method (depending on the part mass, a minimum of 29% is faster). The optimal sheet laminate combination based on the economic criteria for the tool with a radius of 6 mm is presented.
Investigation of the compaction behavior of uni- and bidirectional non-crimp fabrics
Authors: SCHÄFER S.
Published: April 2023

Abstract. The through-thickness compaction behavior of engineering textiles significantly influences the resulting component properties during liquid composite molding processes (LCM). It determines the final fiber volume content and thus the necessary press force, the permeability as well as the final mechanical properties. In the present work, the behavior of a uni- and bidirectional carbon fiber non-crimp fabric (UD- & Biax-NCF) with the same fiber type and areal density of fibers in the respective main reinforcement directions is tested in a punch-to-plate setup. Thereby, the influence of the relative fiber orientation at the interfaces of a layup as well as the number of plies is investigated. A combined influence of roving nesting and superposition of stitching patterns is observed. This results in a common influence of decreasing resistance to compaction for higher numbers of layers, while the relative orientation of the interfaces in a layup is only significant for the Biax-NCF.
Process simulation of friction extrusion of aluminum alloys
Authors: DIYOKE G.
Published: April 2023

Abstract. The friction extrusion (FE) process is a solid-state material processing technique in which a translating extrusion die is pressed against a billet/feedstock material in a rotating extrusion container to produce an extruded rod or wire. A key aspect of FE is the generation of severe plastic deformation and frictional heat due to the relative rotation, leading to an improved microstructure. Numerical simulations of FE are highly complex due to contact between the tool and the workpiece, and the interplay between thermo-mechanical conditions and the present severe plastic deformation. In the present work, a three-dimensional finite element model is developed to study the material flow behavior for different extrusion ratios for a 60° die angle during friction extrusion. The developed model is numerically validated against experimental data. The spatial temperature and strain distributions illustrate the effect of extrusion ratio on the deformation characteristics of the extruded aluminum alloys, thereby assisting in understanding the material flow behavior.
Advanced automatic pass schedule design for hot rolling by coupling reinforcement learning with a fast rolling model
Authors: IDZIK C.
Published: April 2023

Abstract. Rolling is a well-established forming process for producing finished or semi-finished products in various industries. Although highly automated, most rolling processes are designed manually by experts based on their knowledge, highly specialized heuristics and analytical process models or numerical simulations. This manual design approach does not lead to an optimization accounting for multiple objectives. Previous work [1] has shown the potential of coupling reinforcement learning (RL) with fast analytical rolling models (FRM) to optimize hot rolling processes. However, the designed pass schedules do not robustly reach the desired final height within typical industrial tolerances. Therefore, in this paper the existing approach of coupling RL with an FRM is extended by dynamically ranges for height reductions. This extension guarantees that the target height is always reached exactly. In addition to the height reduction, the RL algorithm can determine the inter-pass time, initial slab temperature and rolling velocity. For the optimization, an objective function, called reward function, considering all relevant optimization objectives such as the final grain size and energy consumption, was developed. An exemplary training was performed for a defined starting (140 mm) and final height (25 mm). The resulting, automatically designed pass schedules reach the target height and fulfill all defined optimization objective including the required average austenite grain size.
Modelling failure of joining zones during forming of hybrid parts
Authors: Wester H.
Published: April 2023

Abstract. Combining diverse materials enables the use of the positive properties of the individual material in one component. Hybrid material combinations therefore offer great potential for meeting the increasing demand on highly loaded components. The use of hybrid pre-joined semi-finished products simplifies joining processes through the use of simple geometries. However, the use of pre-joined hybrid semi-finished products also results in new challenges for the following process chain. For example, the materials steel and aluminium may form brittle intermetallic phases in the joining zone, which can be damaged in the following forming process under the effect of thermo-mechanical loads and thus lead to a weak point in the final part. Due to their small thickness as well as their position in the component, the analysis of the joining zone is only possible by complex destructive testing methods. FE simulation therefore offers an efficient way to analyse the development of damage in the process design and to reduce damage by process modifications. Therefore, within this study a damage model based on cohesive zone elements is implemented in the FE software MSC Marc 2018 and calibrated using experimental local tensile tests performed under process relevant conditions.
Multi-scale modeling of the effect of crystallographic texture
Authors: REVIL-BAUDARD B.
Published: April 2023

Abstract. Among processes involving plastic deformation, sheet metal forming requires a most accurate description of plastic anisotropy. One of the main sources of mechanical anisotropy is crystallographic texture, which induces directionality in the macroscopic plastic properties of the polycrystalline metallic alloy sheets (e.g. anisotropy in yield stresses, Lankford coefficients). Recently, we develop a single-crystal yield criterion that satisfies the intrinsic symmetries of the constituent crystals and the condition of insensitivity to hydrostatic pressure [1]. Moreover, this single-crystal criterion is defined for any 3-D stress state. It was shown that the use of this single-crystal criterion for the description of the plastic behavior of the constituent crystals in conjunction with appropriate homogenization procedures leads to an improved prediction of the plastic anisotropy in macroscopic properties under uniaxial loading for polycrystalline aluminum alloys. In this paper, using this polycrystalline model, we simulate the deformation response of sheets of various crystallographic textures. Examples demonstrate the predictive capabilities of the model to describe the influence of the crystallographic texture on the macroscopic behavior and on the final shape of parts obtained using deep-drawing.
As Leis da Captura da Atenção. Reflexões em Torno do Vídeo nas Plataformas Digitais
Authors: Rodrigues Costa Pedro , De Lemos Martins Moisés
Published: April 2023

A imagem é um dos suportes dominantes na comunicação contemporânea (Martins, 2021, p. 185). A convergência cultural atual faz-se, sobretudo, em torno de imagens digitais (Jenkins, 2006/2009). Nesta premissa, o vídeo é um dos tipos que mais destaque alcançam na era da imagem e dos ecrãs (Costa, 2012; Loureiro, 2011; Martins, 2011). Diferentes empresas de comunicação digital, através de diferentes plataformas, utilizam arquiteturas e algoritmos com diferentes técnicas e métodos nos modos como usam a imagem para comunicar e capturar a atenção. O meio digital é pensado tendo como elemento central imagens para comunicar e leis algorítmicas para reter e fidelizar os cidadãos (Lanier, 2010/2010, 2018/2018). Teóricos da economia da atenção entendem que as empresas que gerem as grandes plataformas digitais têm um grande objetivo: capturar a atenção das massas de modo a criar fidelização e retenção nos consumidores/utilizadores (Martens, 2016; Srnicek, 2017). A economia da atenção é um dos seus principais setores, tendo como um dos negócios primordiais a ecranovisão (Costa, 2014). O pagamento do sujeito às empresas que gerem as plataformas digitais é feito por intermédio de um constante dar visualizações (Costa, 2020b), de uma persistente telepresença, de uma frenética partilha de conteúdos, de uma utilização corrente dos inúmeros serviços e ecossistemas digitais. É a soma de muitos a ver, a tele-estar, a tele-partilhar e a tele-usar que permite dinamizar a economia da atenção. As grandes empresas digitais lutam pelas fatias maiores dessa economia. Os que mais utilizadores fidelizam e retêm são os que mais lucram. A estratégia maior reside nos métodos e nas técnicas de captura da atenção utilizados. Essa cria “leis”, quer dizer, regularidades e padrões que se movimentam entre diferentes empresas e diferentes dinâmicas sociotécnicas. O vídeo, enquanto método e técnica de captura da atenção, utiliza “leis” e trilhos, contribuindo para posteriores processos sociais de uso, influência, manipulação, imitação, propagação, socialização e individuação. Neste artigo, tentamos dar conta de algumas regularidades e padrões gerais utilizados no vídeo para captura da atenção das massas.
Adaptation of ACTivate Your Wellbeing, a Digital Health and Well-being Program for Young Persons: Co-design Approach
Authors: Brown Menna , Lord Emily , John Ann
Published: April 2023

Background

ACTivate your wellbeing is a digital health and well-being program designed to support and encourage positive lifestyle behavior change. The website includes 5 lifestyle behavior change modules and a 12-week well-being intervention based on acceptance and commitment therapy. It was timely to adapt the resource for a new audience in the wake of the COVID-19 pandemic. Young persons’ mental health needs have increased substantially, and lifestyle behaviors play a critical role in both mental and physical health statuses.

Objective

This study aimed to adapt an existing health and well-being website for use by young persons aged 16 to 24 years.

Methods

A 3-staged participatory, co-design approach was adopted. The participants reviewed the existing program and provided feedback (stage 1) before cocreating new content (stage 2). Finally, the updated program underwent formative evaluation (stage 3). Two groups were created: one had access for 3 weeks and the other could self-select their study duration. The options were 3 weeks, 60 days, or 90 days. Outcome measures were the Warwick and Edinburgh Mental Well-being Scale, 4-item Patient Health Questionnaire, and Acceptance and Action Questionnaire version 2.

Results

Stage 1 identified that the website was appealing to the new audience (19/24, 79%), and the 3 web-based focus group discussions explored data from the written review in more depth to identify and clarify the main areas for update and adaptation. Overall, 3 themes were developed, and the data informed the creation of 6 tasks for use in 5 web-based co-design workshops. Stage 2 led to the cocreation of 36 outputs, including a new name, new content, scenarios, images, and a new user dashboard, which included streaks and an updated color scheme. After the website update program was completed, 40 participants registered to use the website for formative evaluation (stage 3). Data analysis revealed differences in engagement, completion, and mean well-being after intervention between the 2 groups. The completion rate was 68% in the 3-week duration group, and well-being scores improved after intervention.

Conclusions

Young persons engaged actively with the participatory design process. The participants discussed the updates they desired during the web-based discussions, which worked well via Zoom (Zoom Video Communications Inc) when small groups were used. The participants easily cocreated new content during the web-based co-design workshops. The web-based format enabled a range of participants to take part, share their ideas, search for images, and design digital content creatively together. The Zoom software enabled screen sharing and collaborative whiteboard use, which helped the cocreation process. The formative evaluation suggested that younger users who engage more with the website for a shorter duration may benefit more.