Latxa ardien ustiategien berotegi-efektuaren gasen balantzea bizi-zikloaren analisiaren bidez

[EUS] Azken urte hauetan giza populazioak gorantz egin du, eta ondorioz, gure dietaren parte diren abere-ekoizkinen eskaerak geroz eta altuagoak dira. Abeltzaintzari zor zaio berotegi-efektuaren gasen (BEG) %18a, eta abel-kopuruaren igoerak gas hauen isurketan badu zeresanik. Abere-ekoizkinen eskaera asetzeko asmoz, ekoizpen-intentsitatea emendatu da, abel-buruko ekoizpena geroz eta intentsiboagoa bilakatuz. Euskal Herrian, bertako arraza dugu Latxa ardia, gure lurraldeko klima eta orografiara erabat moldatua. Latxa ardiaren ekoizpen-eredu estentsiboa aldatu egin da antzinatik, landa-eremuak utzi eta larratze-sistemak ordezkatu direlarik. Honenbestez, ekoizpena handitu nahian, ekoizteko modua ere aldatu egin da. Lan honetan, ekoizpen eredu estentsiboko hamabi ustiategietako datuak erabili dira bizi-zikloaren analisiaz (Life Cycle Assessment, LCA) BEGen isurketen estimak egin ahal izateko. Are gehiago, ustiategi hauek ingurumenean izan dezaketen inpaktu negatiboa karbono-aztarna bidez adierazi da. Eredu estentsiboak ingurumenean duen eragin positiboari garrantzia eman nahian, larratzeak lurzoruko karbonoaren bahitze-gaitasunari nola eragin diezaioken erreparatu zaio, eta karbono-aztarna negatibotzat adierazi. Bukatzeko, karbono-aztarnaren balioak apaltzeko, kontuan hartu beharreko zenbait aipamen egin dira

Effects of Gravity and Non-Perpendicularity during Powder-Fed Directed Energy Deposition of Ni-Based Alloy 718 through Two Types of Coaxial Nozzle

The consequences of gravity and the nozzle inclination angle in the powder-fed Directed Energy Deposition (DED) process were examined in this study. We also sought to define guidelines and manufacturing strategies, depending on the DED system configuration and the nozzle type. To do so, two nozzle types were used: a continuous coaxial nozzle with a slit of 0.5 mm and a four-stream discrete coaxial nozzle. Although the main effects of the configurations and the nozzles are well-known, their effects on the clad characteristics and the deposition strategy are as yet unclear. In this paper, measurements of a single clad and the effects of different deposition strategies on cladding applications and inclined walls are presented, and the consequences for manufacturing processes are discussed. Based on a complete study of a single clad, working vertically, five different tilted deposition strategies were applied: three to a single clad and two to an inclined wall. The results for both the single clad and the inclined wall reflect a pattern of changes to height, width, area, and efficiency, at both small and large nozzle angles and deposition strategies. The inclined wall presents a maximum horizontal displacement that can be reached per layer, without geometrical distortions. The amount of material per layer has to be adapted to this limitation.This research was funded by the European Commission through the project "PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based Additive and Subtractive processes with high Efficiency” (Grant Agreement 723440), an initiative of the Public–Private Partnership “Photonics and Factories of the Future”. This research was also funded by European Institute of Innovation & Technology (EIT), through the project "DEDALUS: Directed Energy Deposition machines with integrated process ALgorithms Under dedicated monitoring and control System” (ID 20094), and by the vice-counseling of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza), under the ELKARTEK Program, PROCODA project, grant number KK-2019/00004

Hardness, grainsize and porosity formation prediction on the Laser Metal Deposition of AISI 304 stainless steel

The presented numerical model solves the heat and mass transfer equations in the Laser Metal Deposition process and based on the evolution of the thermal field predicts the grainsize, the resulting hardness and evaluates the pores formation probability in an AISI 304 stainless steel. For this purpose, in a first step, the model calculates the shape of the deposited material and the variations of the temperature field. In a second step, and based on the evolution of the thermal field, the model calculates the resulting hardness of the deposited material, the grainsize and the porosity formation probability after the deposition process. Numerical results are experimentally validated, and good agreement is obtained. Consequently, besides predicting the geometry of the resulting part and the evolution of the thermal field, the developed model enables to evaluate the quality of the deposited material. Therefore, the optimum process conditions and strategy when depositing AISI 304 stainless steel can be determined without initial trial-and-error tests.“LaCaixa” foundation . In addition, this work has been founded by the H2020- FoF13-2016 PARADDISE project (contract No.: 723440). This work has been also carried out in the framework of the DPI2016-79889-R – INTEGRADDI project, funded by the Spanish Ministry of Industry and Competitiveness

Analysis of the Machining Process of Inconel 718 Parts Manufactured by Laser Metal Deposition

Laser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing of near-net-shape products. This could mean significant savings in terms of materials and costs in the manufacturing of high-performance components for the aeronautical industry. In this work, an analysis of how the LMD processing of alloy 718 affects the final machining has been carried out. For this purpose, a comparative study has been done by means of the monitoring of the end milling process of a part manufactured by LMD and a rough-milled part from forged material. Differences between process outputs such as chip morphology and cutting forces were studied. Material characteristics such as microstructure, hardness and mechanical properties were also analyzed.This research was funded by European Commission grant number 723440 (PARADDISE project), which is an initiative of the Photonics and Factories of the Future Public Private Partnership, and by the Vice-Counselor of Technology, Innovation and Competitiveness of the Basque Government grant number KK-2018/00115 (ADDISEND project) and grant number KK-2019/00004 (PROCODA project)

Latxa ardien ustiategien berotegi-efektuaren gasen balantzea bizi-zikloaren analisiaren bidez

[EUS] Azken urte hauetan giza populazioak gorantz egin du, eta ondorioz, gure dietaren parte diren abere-ekoizkinen eskaerak geroz eta altuagoak dira. Abeltzaintzari zor zaio berotegi-efektuaren gasen (BEG) %18a, eta abel-kopuruaren igoerak gas hauen isurketan badu zeresanik. Abere-ekoizkinen eskaera asetzeko asmoz, ekoizpen-intentsitatea emendatu da, abel-buruko ekoizpena geroz eta intentsiboagoa bilakatuz. Euskal Herrian, bertako arraza dugu Latxa ardia, gure lurraldeko klima eta orografiara erabat moldatua. Latxa ardiaren ekoizpen-eredu estentsiboa aldatu egin da antzinatik, landa-eremuak utzi eta larratze-sistemak ordezkatu direlarik. Honenbestez, ekoizpena handitu nahian, ekoizteko modua ere aldatu egin da. Lan honetan, ekoizpen eredu estentsiboko hamabi ustiategietako datuak erabili dira bizi-zikloaren analisiaz (Life Cycle Assessment, LCA) BEGen isurketen estimak egin ahal izateko. Are gehiago, ustiategi hauek ingurumenean izan dezaketen inpaktu negatiboa karbono-aztarna bidez adierazi da. Eredu estentsiboak ingurumenean duen eragin positiboari garrantzia eman nahian, larratzeak lurzoruko karbonoaren bahitze-gaitasunari nola eragin diezaioken erreparatu zaio, eta karbono-aztarna negatibotzat adierazi. Bukatzeko, karbono-aztarnaren balioak apaltzeko, kontuan hartu beharreko zenbait aipamen egin dira

Strategy Development for the Manufacturing of Multilayered Structures of Variable Thickness of Ni-Based Alloy 718 by Powder-Fed Directed Energy Deposition

In this study, a manufacturing strategy, and guidelines for inclined and multi-layered structures of variable thickness are presented, which are based on the results of an own-developed geometrical model that obtains both the coating thickness and dilution. This model is developed for the powder-fed directed energy deposition process (DED) and it only uses the DED single-track cladding characteristics (height, width, area, and dilution depth), the overlap percentage, and the laser head tilting-angle as inputs. As outputs, it calculates both the cladding geometry and the dilution area of the coating. This model for the Ni-based alloy 718 was improved, based on previous studies of the single clad working both vertically and at an inclined angle, adding the equations of the single clad characteristics with respect to the main process parameters. The strategy proposed in this paper for multilayered cladding consisted of both adding an extra clad at the edges of the layer and using a variable value of the overlap percentage between clads for geometric adaptations. With this strategy, the material deposition is more accurate than otherwise, and it shows stable growth. Manufacturing a multilayered wall of wider thicknesses at higher heights was utilized to validate the strategy.This research was funded by the European Commission through the project “PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based Additive and Subtractive processes with high Efficiency” (Grant Agreement 723440), an initiative of the Public-Private Partnership “Photonics and Factories of the Future”. This research was also funded by European Institute of Innovation & Technology (EIT) through the project “DEDALUS: Directed Energy Deposition machines with integrated process Algorithms Under dedicated monitoring and control System” (ID 20094) and by the vice-counseling of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza) under the ELKARTEK Program, PROCODA and QUALYFAM projects, grant number KK-2019/00004 and KK-2020/00042, respectively

Geometrical model and strategy in single and multilayer structures deposited by powder-fed Directed Energy Deposition

This work presents a geometrical model of coatings fabricated by powder-fed Directed Energy Deposition (DED) and defines guidelines and manufacturing strategies for multilayered structures based on the geometrical model results. This model obtains as output both the overlapped clad geometry and the dilution area of the coating at different input parameters and defines the strategy of multi-layer structures. The results of this work validate the model that comes in handy: a) To understand the influence of each parameter and the single clad geometry when fabricating coatings and structures; b) To select the parameters depending on the requirements of the coating like effective thickness and dilution; c) To detect lack of fusion with the substrate due to an excessive overlap percentage; d) To select the deposition strategy and the tool path for additive manufacturing; e) To select the subsequent machining strategy based on the predicted geometry of the model.The authors acknowledge support from the European Commission through the project "PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based Additive and Subtractive processes with high Efficiency” (Grant Agreement 723440), an initiative of the Public-Private Partnership “Photonics and Factories of the Future”. The authors also acknowledge support from the European Institute of Innovation & Technology (EIT) through the project "DEDALUS: Directed Energy Deposition machines with integrated process ALgorithms Under dedicated monitoring and control System” (ID 20094), an initiative of the EIT Manufacturing. Finally, the authors acknowledge the vice-counseling of technology, innovation and competitiveness of the Basque Country for support of the project “PROCODA: Procesos de alto valor basados en el conocimiento y los datos” (KK2019/00004) within Elkartek 2019 and the project “ADDISEND: cooperación cientifica en fabricación aditiva para un control robusto de la cadena de valor” (kk2018/00115)

Effects of the Nozzle Tip Clogging and the Scanning Direction on the Deposition Process During Laser Metal Deposition of Alloy 718 Using a Four-Stream Discrete Nozzle

Depending on the configuration of the LMD system, the nozzle tilting is necessary to be able to manufacture parts with complex geometry. In these cases, the use of discrete coaxial nozzles is recommended. With this type of nozzle, the powder can clog the internal tips of the nozzle streams due to an inappropriate shape, size distribution, humidity or temperature conditions of the powder particles during the deposition process. This undesired effect can be an opportunity depending on the combination of the activated powder tips for coating complex surfaces when the geometry of the substrate acts as a barrier for the powder stream. This work presents for first time the effect of the scanning direction and the stream clogging on the deposition process in terms of powder efficiency, Material Deposition Rate (MDR) and clad geometry and dimensions, when Alloy 718 is deposited by LMD using a four-stream discrete coaxial nozzle.The authors acknowledge the European Commission for support of Project "PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based ADDItive and Subtractive processes with high Efficiency” (Grant Agreement 723440), which is an initiative of the Photonics and Factories of the Future Public Private Partnership. The authors also acknowledge the Spanish Ministry of Economy and Competitiveness for support of the project "ADDICLEAN: hybrid technology of eco-efficient manufacturing of pieces of high added value" (RTC-2015-4194-5). Finally, the authors acknowledge the council of technology, innovation and competitiveness of the Basque Country for support of the project “ADDISEND: Scientific cooperation in additive manufacturing for a robust control of the value chain” (2018/00115) within Elkartek 2018

Characteristics of Fe-, Ni- and Co-based Powder Coatings Fabricated by Laser Metal Deposition without Preheating the base Material

The objective of this work was to select the best material from Fe-, Ni- and Co-based alloy powder for coating, by Laser Metal Deposition (LMD) the filets of a hardened 42CrMoS4 extrusion screw without preheating process. Even though most of the articles recommended preheating the base material as a condition for a crack free coating, the time wasted in the process decrease the productivity and distortions can be also generated in the part. In this work, a comparison of the main characteristics of the coatings done on preheated and non-preheated base material has been made. The relationships between the relevant LMD parameters (feed rate, laser power, and powder feeding rate) and the main geometrical characteristics of a single clad (height, width, dilution, deposition rate, efficiency, etc.) were examined. In addition, different characteristics of overlapped clads in a preheated, non-preheated and a hardened base material have been also analyzed. All the study was made in the Ibarmia ZVH 45/1600 Add+Process hybrid machine with a high power Yb-Fiber laser (3 kW) and discrete coaxial LMD head. Coatings with thickness from 1.2 to 0.76 were created without cracks and other defects except in the case of Ni-based coating. The microstructural features of these coatings were studied using optical and scanning electron microscopy. The mechanical properties were determined using microhardness measurements and a pin on disk tribometer.The authors acknowledge the European Commission for support of Project "PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based ADDItive and Subtractive processes with high Efficiency” (Grant Agreement 723440),which is an initiative of the Photonics and Factories of the Future Public Private Partnership

Astrocytes in Alzheimer’s Disease: Pathological Significance and Molecular Pathways

Astrocytes perform a wide variety of essential functions defining normal operation of the nervous system and are active contributors to the pathogenesis of neurodegenerative disorders such as Alzheimer’s among others. Recent data provide compelling evidence that distinct astrocyte states are associated with specific stages of Alzheimer´s disease. The advent of transcriptomics technologies enables rapid progress in the characterisation of such pathological astrocyte states. In this review, we provide an overview of the origin, main functions, molecular and morphological features of astrocytes in physiological as well as pathological conditions related to Alzheimer´s disease. We will also explore the main roles of astrocytes in the pathogenesis of Alzheimer´s disease and summarize main transcriptional changes and altered molecular pathways observed in astrocytes during the course of the disease.This work was supported by the FEDER/Ministerio de Ciencia e Innovación—Agencia Estatal de Investigación grant RTI2018-101850-A-I00 to A.M.A. (Spain), and a start-up grant from the IKERBASQUE Basque Foundation of Science to A.M.A