Exergy Analysis as a Developed Concept of Energy Efficiency Optimized Processes: The Case of Thermal Spray Processes

AbstractGiven the global economic growth and the rapid manufacturing development, the energy and resource efficiency will become an increasingly competitive factor and scope for the companies in the road of sustainability. Among energy efficiency optimization approaches, thermodynamics methodologies contribute toward the improvement of energy efficiency in manufacturing processes. Besides energy balance, exergy has been recently considered as a practical thermodynamics method for system's energy evaluation. From the exergy analysis, merging both exergy efficiency and exergy destruction highlights the energy inefficiencies within a system and provides useful information to the managers and decision makers for prioritizing the improvement potentials. Exergy analysis is generally an applicable method for the comparison of the alternative processes for a given purpose.In this study, thermal spray process techniques (APS, SPS, HVOF, HVSFS) as energy intensive manufacturing processes are analyzed and compared on the basis of exergy and energy analysis methods. For a comprehensive evaluation, energy efficiency as well as exergy efficiency and exergy destruction are proposed as the indicators.This work concludes with a discussion of the advantages of the exergy analysis method in comparison with a conventional energy efficiency evaluation by validation of the results for the case of thermal spray processes

Influence of heat treatments on YSZ electrolyte for sofc manufactured by HVSFS

High-velocity suspension flame spraying (HVSFS) is a promising technology to manufacture yttria stabilized zirconia (YSZ) as solid electrolyte for solid oxide fuel cells (SOFC). In this paper isothermal ageing and thermal cycling have been carried out in order to evaluate their microstructural and mechanical stability. X-ray diffraction (XRD), scanning electron microscopy (SEM) and focused ion beam (FIB) techniques have used to analyze the microstructure of YSZ electrolyte before and after ageing at high temperature. Elastic modulus has been monitored by nanoindentation, while scratch tests have been performed in order to estimate the influence of ageing on the interface electrolyte/anode adhesion.Postprint (published version

Status of the BELLE II Pixel Detector

The Belle II experiment at the super KEK B-factory (SuperKEKB) in Tsukuba, Japan, has been collecting $e^+e^−$ collision data since March 2019. Operating at a record-breaking luminosity of up to $4.7×10^{34} cm^{−2}s^{−1}$, data corresponding to $424 fb^{−1}$ has since been recorded. The Belle II VerteX Detector (VXD) is central to the Belle II detector and its physics program and plays a crucial role in reconstructing precise primary and decay vertices. It consists of the outer 4-layer Silicon Vertex Detector (SVD) using double sided silicon strips and the inner two-layer PiXel Detector (PXD) based on the Depleted P-channel Field Effect Transistor (DePFET) technology. The PXD DePFET structure combines signal generation and amplification within pixels with a minimum pitch of $(50×55) μm^2$. A high gain and a high signal-to-noise ratio allow thinning the pixels to $75 μm$ while retaining a high pixel hit efficiency of about $99$. As a consequence, also the material budget of the full detector is kept low at $≈0.21$$\frac{X}{X_0}$ per layer in the acceptance region. This also includes contributions from the control, Analog-to-Digital Converter (ADC), and data processing Application Specific Integrated Circuits (ASICs) as well as from cooling and support structures. This article will present the experience gained from four years of operating PXD; the first full scale detector employing the DePFET technology in High Energy Physics. Overall, the PXD has met the expectations. Operating in the intense SuperKEKB environment poses many challenges that will also be discussed. The current PXD system remains incomplete with only 20 out of 40 modules having been installed. A full replacement has been constructed and is currently in its final testing stage before it will be installed into Belle II during the ongoing long shutdown that will last throughout 2023

Process Technology, Applications and Thermal Resistivity of Basalt Fiber Reinforced SiOC Composites

Promising lightweight composite materials, bridging the gap between Polymer and Ceramic Matrix Composites, are manufactured as polymer derived ceramics by the use of polysiloxanes and basalt fibers. Such competitive free formable Hybrid Composites are supposed to be capable for lightweight applications in a temperature range between 300 °C and 850 °C and short time exposure up to over 1000 °C, even in oxidative atmosphere. Cheap raw materials like basalt fibers and siloxane resins in combination with performing manufacturing technologies can establish completely new markets for intermediate temperature composites. These attributes enable the Hybrid Composites as ideal material for fire retardant applications in automotive engineering and public transportation, as well as in fire protection systems in electrical and civil engineering applications. In this study, the most prominent fields of application and engineering solutions for Hybrid-CMC are reviewed and the results of the thermal resistivity analysis effectuated on basalt fiber reinforced SiOC samples are presented. This study consisted of several air exposures between 1 h and 50 h and temperatures in the range of 650 °C to 1100 °C. Remaining mechanical resistance was characterized by Impulse Excitation Technique (IET) and Interlaminar Shear Strength (ILSS) tests. Basalt fiber reinforced samples exhibited a decent level of mechanical performance even after the most demanding exposures. Due to the poor oxidation resistance of carbon fibers, Cf/SiOC composites were completely degraded after long-term exposure at 500 °C in air

Enhanced Mechanical Properties in ED-Machinable Zirconia-Tungsten Carbide Composites with Yttria-Neodymia Co-Stabilized Zirconia Matrix

The electrical discharge machining-process (EDM) is a smart solution to optimize the manufacturing chain of customized and complex shaped ceramic components. To comply with the high requirements for the machine and mold design, it is necessary to improve the mechanical properties of ED-machinable ceramics. In this study, ceramic composites with a tetragonal zirconia matrix and tungsten carbide as electrically conductive dispersion were investigated. To improve the toughness of this high strength material, co-stabilized zirconia coated with yttria and neodymia as dopants were used in the compositions with 1.5/1.5 and 1.75/1.25 mol %. These recipes were compared to commercial 3Y-TZP as a reference matrix material combined with the same WC raw powder. The electrically conductive phase content was varied from 20 to 28 vol %. For all compositions, the ceramic blanks were hot pressed at identical dwell and pressure, but with various sintering temperatures (1300 °C to 1450 °C) and then tested with respect to the mechanical and electrical properties. By variation of the stabilizer system, a significantly higher toughness of up to 11.3 MPa√m compared to 5.3 MPa√m for 3Y-TZP-20WC is achieved while the bending strength stays at a comparable high level of >1500 MPa

Proceedings of IV Advanced Ceramics and Applications conference

This is the Proceedings of IV Advanced Ceramics and Applications conference, held in Belgrade, Serbia in 2015

Inversely 3D-printed β-TCP scaffolds for bone replacement

The aim of this study was to predefine the pore structure of β-tricalcium phosphate (β-TCP) scaffolds with different macro pore sizes (500, 750, and 1000 µm), to characterize β-TCP scaffolds, and to investigate the growth behavior of cells within these scaffolds. The lead structures for directional bone growth (sacrificial structures) were produced from polylactide (PLA) using the fused deposition modeling techniques. The molds were then filled with β-TCP slurry and sintered at 1250° C, whereby the lead structures (voids) were burnt out. The scaffolds were mechanically characterized (native and after incubation in simulated body fluid (SBF) for 28 d). In addition, biocompatibility was investigated by live/dead, cell proliferation and lactate dehydrogenase assays