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.
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.
Three-dimensional printing is one of the emerging technologies that is gaining interest from the pharmaceutical industry as it provides an opportunity to customize drugs according to each patient's ...needs. Combining different active pharmaceutical ingredients, using different geometries, and providing sustained release enhances the effectiveness of medicine. One of the most innovative uses of 3D printing is producing fabrics, medical devices, medical implants, orthoses, and prostheses. This review summarizes the various 3D printing techniques such as stereolithography, inkjet printing, thermal inkjet printing, fused deposition modelling, extrusion printing, semi-solid extrusion printing, selective laser sintering, and hot-melt extrusion. Also, discusses the drug relies profile and its mechanisms, characteristics, and applications of the most common types of 3D printed API formulations and its recent development. Here, Authors also, summarizes the central flow of 3D food printing process and knowledge extension toward personalized nutrition.
Display omitted
•Summarized the mechanisms, characteristics, and applications of 3D printing technologies•Discussed 3D printing methods to develop pharmaceutical drugs and their significant drug load and delivery•Highlights different 3D printing drug delivery devices•Summarized the process of 3D food printing in relation to personalized nutrition and its commercial developments.
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.
Display omitted
Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are ...limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.
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.
This experimental study investigates the effect of filling pattern on tensile and flexural strength and modulus of the parts printed via fused deposition modeling (FDM), 3D printer. The main downside ...of the printed products, with an FDM 3D printer, is the low strength compared to the conventional processes such as injection molding and machining. The issue stems from the low strength of thermoplastic materials and the weak bonding between deposited rasters and layers. Selection of proper filling pattern and infill percentage could highly influence the final mechanical properties of the printed products that were experimentally explored in this research work. Concentric, rectilinear, hilbert curve, and honeycomb patterns and filling percentage of 20, 50 and 100 were the variable parameters to print the parts. The results indicate that concentric pattern yields the most desirable tensile and flexural tensile properties, at all filling percentages, apparently due to the alignment of deposited rasters with the loading direction. Hilbert curve pattern also yielded a dramatic increase in the properties, at 100% filling. The dramatic increase could be mainly attributed to the promotion of strong bonding between the rasters and layers, caused by maintaining a high temperature of rasters at short travelling distances of nozzle for the hilbert curve pattern. Scanning electron microscopy (SEM) examination revealed the strong bonding between rasters and sound microstructures (less flaws and voids) for concentric and hilbert curve pattern at a high filling percentage of 100. Besides, SEM examination revealed large voids in honeycomb pattern, deemed to be responsible for its lower strength and modulus, especially at the filling percentage of 100.
PDF
