PV panellerinin radyasyon miktarına bağlı olarak ısınması ve veriminin düşmesi bilinen ve üzerinde birçok çalışma yapılan bir olgudur. PV panellerin soğutulması için panel tabanına FDM eklenmesi ise ...literatürde yaygın olarak görülen bir pasif soğutma yöntemidir. Bu çalışmada ise PV panel tabanına FDM eklenmesi ve farklı hacim oranlarında FDM nanopartikül karışımı eklenmesi durumunda PV panel sıcaklığı, panel verimi, elektrik üretimi ve FDM konteynerindeki erime oranları 1-B matematiksel model kullanılarak incelenmiştir. Çalışma 800, 1000, 1200 W/m2 radyasyon değerleri için gerçekleştirilmiştir. Sonuçlar incelendiğinde en yüksek verim ve elektrik üretimi değerlerinin hacimce 0.5 nanopartikül PCM karışımı için elde edildiği görülmüştür. Verim ifadesi hacimce 0.5 nanopartikül karışımı için 800, 1000 ve 1200 W/m2 için sırasıyla % 18.3, %17.7 ve %17.2 olarak elde edilmiştir ki bu değerler geleneksel PV panelinden yaklaşık %1 fazladır. Eleltrik üretimi ise yine 0.5 nanopartikül FDM karışımı için sırasıyla 112.5, 128 ve 158 W olarak elde edilmiştir ve bu değerler geleneksel PV panelden sırasıyla 5, 7 ve 8 W daha fazladır.
PV panellerinin radyasyon miktarına bağlı olarak ısınması ve veriminin düşmesi bilinen ve üzerinde birçok çalışma yapılan bir olgudur. PV panellerin soğutulması için panel tabanına FDM eklenmesi ise literatürde yaygın olarak görülen bir pasif soğutma yöntemidir. Bu çalışmada ise PV panel tabanına FDM eklenmesi ve farklı hacim oranlarında FDM nanopartikül karışımı eklenmesi durumunda PV panel sıcaklığı, panel verimi, elektrik üretimi ve FDM konteynerindeki erime oranları 1-B matematiksel model kullanılarak incelenmiştir. Çalışma 800, 1000, 1200 W/m2 radyasyon değerleri için gerçekleştirilmiştir. Sonuçlar incelendiğinde en yüksek verim ve elektrik üretimi değerlerinin hacimce 0.5 nanopartikül PCM karışımı için elde edildiği görülmüştür. Verim ifadesi hacimce 0.5 nanopartikül karışımı için 800, 1000 ve 1200 W/m2 için sırasıyla % 18.3, %17.7 ve %17.2 olarak elde edilmiştir ki bu değerler geleneksel PV panelinden yaklaşık %1 fazladır. Eleltrik üretimi ise yine 0.5 nanopartikül FDM karışımı için sırasıyla 112.5, 128 ve 158 W olarak elde edilmiştir ve bu değerler geleneksel PV panelden sırasıyla 5, 7 ve 8 W daha fazladır.
The development of Additive Manufacturing (AM) has greatly facilitated the fabrication of cellular and lattice materials. Gyroid-based lattice structures, known for their distinctive properties such ...as interconnected porosity, high surface-to-volume ratio, and remarkable structural stiffness combined with specific energy absorption, have been extensively explored. Many studies examining the impact of design parameters on the mechanical properties of Gyroid lattice materials have utilized metal AM techniques. This research aims to evaluate the influence of two design parameters on the compressive properties of Gyroid structures obtained by fused filament fabrication (FFF). A full factorial analysis was employed to assess the effects of cell size and wall thickness on the compressive properties of polylactic acid (PLA) Gyroid lattices. Cell sizes were varied between 4 mm, 5 mm, and 10 mm, while wall thickness ranged from 0.4 mm, 0.6 mm, to 0.8 mm. After 3D printing, the print quality was assessed, samples were weighted and then subjected to compression testing. During compression, the lattices with 10 mm cells exhibited successive layer collapse, whereas the lattice with 4 mm and 5 mm cells displayed plastic deformation, marked by a plateau in the stress-strain curve. These behaviours were mostly independent of wall thickness, except for the 5 mm cell lattice with 0.4 mm wall thickness. The elastic modulus, yield stress and absorbed energy per volume aligned with the apparent density of the lattices, ranging between 1% and 12% of the bulk 3D printed material for both the stiffness and yield stress, and between 1% and 22% for the energy absorbed. Analysis of the fitted means indicated that doubling the cell size had a more significant impact on the measured properties than doubling the wall thickness, while doubling both the cell size and wall thickness exerted a more pronounced influence on the yield stress and strain. Notably, under the conditions of this study, the 3D printed PLA Gyroids behaved similarly to closed cell foams, despite their interconnected channels. Their compressive mechanical properties comparable to those of rigid polyurethane foams with closed cells.
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•Larger cells structures failed by brittle collapse of their layers, showing multiples peaks in the stress-strain curves.•Smaller cells structures failed plastically, showing a stress-strain plateau typical from bend-dominated cellular materials.•The failure behaviours were generally independent of wall thickness.•The observed elastic modulus and yield stress ranged between 1% and 12% of the bulk 3D printed material.•The energy absorbed per volume ranged between 1% and 22% of the bulk 3D printed material.
Bei urheberrechtlichen Fragen im Forschungsdatenmanagement stehen Forschende und Beratungspersonal vor besonderen Herausforderungen. Einerseits verlangt die gute wissenschaftliche Praxis, mögliche ...Urheber- und Leistungsschutzrechte an Forschungsdaten frühzeitig zu klären, zum Beispiel durch Verträge zwischen Projektbeteiligten oder durch institutionelle Richtlinien. Andererseits ist die Rechtslage im Forschungsalltag oft sehr komplex und es mangelt an Unterstützung bei der Formulierung der notwendigen Vereinbarungen. Dieser Übersichtsartikel führt kurz in die für Forschungsdaten relevanten Aspekte des Urheberrechts ein und zeigt anhand zweier Fallbeispiele häufig vorkommende Unsicherheiten auf. Wir regen an, Muster- und Beispieltexte, die das Urheberrecht betreffen, in einem koordinierten, einrichtungsübergreifenden Prozess zu entwickeln und zentral zur Nachnutzung zur Verfügung zu stellen. Außerdem schlagen wir vor, ein Online-Unterstützungsangebot aufzubauen, das bei der Klärung urheberrechtlicher Fragen hilft und der Weiterentwicklung und Kommentierung bestehender Musterdokumente dient.
Mobile fronthaul is an important network segment that bridges wireless baseband units and remote radio units to support cloud radio access network. We review recent progresses on the use of ...frequency-division multiplexing to achieve highly bandwidth-efficient mobile fronthaul with low latency. We present digital signal processing (DSP) techniques for channel aggregation and deaggregation, frequency-domain windowing, adjacent channel leak age ratio reduction, and synchronous transmission of both the I/Q waveforms of wireless signals and the control words (CWs) used for control and management purposes. In a proof-of-concept experiment, we demonstrate the transmission of 48 20-MHz LTE signals with a common public radio interface (CPRI) equivalent data rate of 59 Gb/s, achieving a low round-trip DSP latency of <;2 μs and a low mean error-vector magnitude (EVM) of ~2.5% after fiber transmission. In a follow-up experiment, we further demonstrate the transmission of 32 20-MHz LTE signals together with CPRI-compliant CWs, corresponding to a CPRI-equivalent data rate of 39.32 Gb/s, in single optical wavelength channel that requires an RF bandwidth of only ~1.6 GHz. After transmission over 5-km standard single-mode fiber, the CWs are recovered without error, while the LTE signals are recovered with an EVM of lower than 3%. Applying this technique to future 5G wireless networks with massive multiple-input multiple-output is also discussed. This efficient mobile fronthaul technique may find promising applications in future integrated fiber/wireless access networks to provide ultrabroadband access services.
STUDY ON OPTIMIZING MATERIALS FOR 3D GRIPPER PRINTING Paduraru, Emilian; Dumitras, Catalin Gabriel; Chitariu, Dragos Florin ...
International Journal of Modern Manufacturing Technologies,
12/2022, Letnik:
14, Številka:
2
Journal Article
The purpose of this paper is to identify the material that offers optimal characteristics in terms of cost, strength and weight. This is necessary because more and more composite materials and 3D ...printing are being used in the construction of robots, including the gripper. In this context, two types of materials are considered possible to be used in the construction of grippers. Samples are made in different 3D printing modes; the Taguchi method is applied to identify the optimal values. A finite element analysis was also performed in order to verify the characteristics of the materials introduced in the program by comparison with the experimental results in order to use them in the analysis of a new gripper solution. As they will follow, PLA material with 100% infill, 0,17mm layers thickness and 45° raster angle has the greatest resistance at extension. This material definition will be used in future research to the entire model of the gripper to see the behavior in different conditions given by the current requirements.
The employment of tissue engineering scaffolds in the reconstruction of the damaged bone tissues has shown remarkable promise since they significantly facilitate the healing process. Fabrication of ...highly porous biocompatible scaffolds with sufficient mechanical strength is still challenging. In this regard, polymers have been widely utilized to construct three-dimensional (3D) porous scaffolds due to their excellent processability and biocompatibility. However, insufficient mechanical strength and inappropriate degradation rate of the monophasic polymer scaffolds in the bone regeneration process, as the main challenges, limit their extensive clinical application. The incorporation of metallic fillers into the polymer matrix has been shown to be helpful due to their strengthening effect and magnificent impact on the biological properties of the polymer-based 3D porous scaffolds, including cell viability, osteogenic, angiogenic and antibacterial properties. In this paper, fabrication of the polymer/metal composite 3D porous scaffolds by additive manufacturing techniques, as the most convenient approache to construct complex polymer-based parts, their structural, mechanical, biodegradation, biocompatibility, osteogenic and angiogenic features have been reviewed. Furthermore, new perspectives have been proposed to promote the implementation of polymer/metal composite scaffolds in bone tissue engineering practices.
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Abstract
As a core technology in the field of high and new tech manufacturing,3D printing occupies an important position in the production process of aviation, shipbuilding, and automobiles. With the ...rapid development of 3D printing basic theory in recent years, how to further improve product accuracy, quality and modeling efficiency has become the current research focus in this field. Firstly, we conducted further research on the key technologies of FDM 3D printer, and combining 3D reconstruction technology with pretreatment technology. Secondly, we constructed and optimized the corresponding model layered slice and filling path planning algorithm. Thirdly, we designed a 3D suitable for rapid prototyping products printing control system. The research can provide an effective experience for the application of 3D printing technologies.
Abstract
The purpose of this paper is to present the analysis of the efficiency and strength of 3D printed parts due to the variation shown in print orientation. Fused deposition modeling (FDM) is a ...widely used technique in which the melt extrusion method is used to deploy the thermal plastics as filaments in a specific pattern. In recent years, the revolutionary method has changed the field of rapid manufacturing. This has become one of the most common methods for printing polymer-based composite components. The investigation is done based on the print orientation effects on the macrostructure, the mechanical properties, and the strain field behavior of PLA (polylactic acid) filament. Based on the analysis, the properties of an object are optimized to increase mechanical strength when manufactured. By fixing the similar print properties across all different orientations helps to identify the differences in the structural and other mechanical properties, which projects a clear understanding of the impact received and thus provides a way to enhance the structural strength of the prints.
Additive manufacturing technologies provide new opportunities for the manufacturing of components with customisable geometries and mechanical properties. In particular, fused deposition modelling ...(FDM) allows for customisable mechanical properties by controlling the void density and filament orientation. In this work, a methodology is provided for the prediction of the mechanical properties and mesostructure of FDM polymers. To this end, we propose a computational framework for the simulation of the printing process taking as input data specific manufacturing parameters and filament properties. A new two-stage thermal and sintering model is developed to predict the bond formation process between filaments. The model predictions are validated against original experimental data for acrylonitrile butadiene styrene (ABS) components manufactured by FDM. A parametric study is finally presented to interpret the effects of different manufacturing parameters on the mechanical performance of ABS specimens. Overall, the proposed framework offers new avenues for the design of 3D printed polymeric components with custom properties, directly in terms of manufacturing settings.
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•FDM ABS specimens are tested for different combinations of printing parameters.•A two-stage model is proposed to simulate the FDM manufacturing process.•The model predicts thermal conditions and sintering within filaments.•Analytical expressions are established for FDM ABS.•Layer height and environment temperature main drivers for mechanical properties.
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