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This is an accepted manuscript of an article published by Elsevier in Reference Module in Materials Science and Materials Engineering on 15/07/2021, available online: https://doi.org/10.1016/B978-0-12-815732-9.00114-5 The accepted version of the publication may differ from the final published version.

This is an accepted manuscript of a chapter published by Elsevier in Reference Module in Materials Science and Materials Engineering on 22/10/2020, available online: https://doi.org/10.1016/B978-0-12-815732-9.00027-9 The accepted version of the publication may differ from the final published version

This is an accepted manuscript of a chapter published by Elsevier in Reference Module in Materials Science and Materials Engineering on 22/10/2020, available online: https://doi.org/10.1016/B978-0-12-815732-9.00034-6 The accepted version of the publication may differ from the final published version

Light-emitting diodes (LED) are widely used in today’s world due to its less power consumption and its high luminance capacity. Around 20–30% of energy is converted to light energy and 70–80% of en...

Light-emitting diode (LED) has several advantages and applications due to energy efficiency, versatility, performance, and long life. LED converts only 20–30% of the power input into light, convert...

Fabrication of electronic circuits and the effects of optimization parameters on electrical conductivity of the printed circuits fabricated by direct ink writing method (D.I.W); one of the novel methods in 3D printing technologies is discussed in this work. This paper focuses on fabrication of electronic circuits using F-MWCNT/PVA conductive ink and analyses the effect of input printing process parameters namely nozzle diameter, extrusion pressure, printing speed on evaluating the electrical conductivity. Box–Behnken approach is followed to generate the levels of experiments and the performance of developed model is assessed using ANOVA. Response surface method is incorporated to find the influencing parameters on electrical conductivity response. Two-point probe measurement method is performed to analyse the output response of the printed electronic circuits. Optimized printing parameters such as nozzle diameter of 0.8 mm, extrusion pressure of 0.1 MPa and printing speed of 4 mm/sec are found to be the best the for printing electronic circuits with high electrical conductivity.

Metallic foams are among the most promising class of materials due to their unique mechanical properties combining low mass with high stiffness, excellent energy absorption, and vibroacoustic damping. Consequently, noise control using methodically engineered metallic foams has received increased attention from both industrial and scientific community. Accordingly, this paper aims to present the mechanism of sound absorption along with the experimental and theoretical procedure that can be used to classify metallic foams. Additionally, the influence of design parameters on the resulting sound absorption coefficient of closed and open-cell metallic foams are explored. While Aluminium foams used to dominate the literature when it comes to acoustics, recent studies have reported Nickel-Inconel superalloy and Copper foams as having superior sound absorption coefficients.

Light-emitting diodes (LEDs) are steadily growing lighting technology due to its reduced energy consumption, high light output and better lifetime as compared to incandescent lighting. However, the heat generated at LED chip during its operation, poses a considerable hurdle in its growth. In LEDs, about 70–85% of total energy is converted as heat, and only remaining 15–30% is harnessed as light energy. Excessive rise in the junction temperature (>95 °C) can cause failure of LEDs. The goal of this study is to experimentally investigate the heat transfer performance of the heat sinks using 16 W LED. The variation of case and junction temperature in LED for different configured heat sinks such as bare and finned heat sink was studied. It was observed that the case temperature (Tc) and junction temperature (Tj) reduced by 37.6 and 28.3%, respectively, for the finned heat sink as compared to the bare heat sink.

Experiments are conducted to assess the heat transfer benefits of the hydrophilic coating on a rectangular minichannel. The spray pyrolysis technique is used to obtain the surfactant added ZnO–Al 2 O 3 coatings. The effect of surfactant weight percentage on hydrophilicity has been investigated using the static contact angle meter. An appreciable enhancement in the critical heat flux (CHF) and the average heat transfer coefficient (HTC) are observed on surfactant added ZnO–Al 2 O 3 coatings compared to pure ZnO coatings. A maximum enhancement of 44.6% in CHF and 29.7% in HTC are observed for the 4 wt.% surfactant added ZnO–Al 2 O 3 composite coating, for a mass flux of 88 kg/m 2 s.

In this work, high velocity oxy-fuel (HVOF) thermal spraying was used to develop 65 wt% NiCrSiB–35 wt% WC–Co coatings on AISI 304 stainless steel substrate. Taguchi method was taken to optimize the spray parameters like oxygen flow rate, fuel flow rate, powder feed rate and standoff distance to obtain better erosion resistance at 90° impact angle. Standoff distance and powder feed rate were identified as the highly contributing parameters on the erosion wear loss. The important sequence of the spray parameter is standoff distance>powder feed rate>fuel flow rate>oxygen flow rate. The combination of 220 lpm of oxygen flow rate, 65 lpm of fuel flow rate, 28 g/min of powder feed rate and 300 mm of standoff distance was identified as the optimum condition for minimum erosion wear loss. The microstructure of the optimized coating was characterized using Scanning Electron Microscope (SEM) equipped with Energy dispersive spectroscopy (EDS), Optical microscope (OM), and X-Ray Diffraction (XRD). The microhardness, porosity and surface roughness of the coating was also measured. Finally, erosion wear testing of the optimized coating was conducted at 30°, 60° and 90° impact angle using hot air jet erosion testing machine. The SEM images of the erodent samples were taken to analyse the erosion mechanism.

In this work, 60 wt.% NiCrSiB–40 wt.% Al 2 O 3 composite coating was produced on AISI 304 substrate material using the atmospheric plasma spraying technique. The coating surface has been characterised using a scanning electron microscope (SEM), optical microscope and X-ray diffractometer (XRD). The microhardness, porosity, density and surface roughness of the coating were measured. The adhesion strength of the coating was measured using pull off adhesion tester. The erosion behaviour of plasma sprayed coating was studied at 450 °C using hot air jet erosion testing machine. The erosion rate of coated and uncoated samples was evaluated at 30° and 90° erodent impact angles. The SEM images of the eroded samples were taken to analyse the erosion mechanism. The test results reveal that the coating protects the substrate at both 30° and 90° impact angles.

Usage of conductive materials for manufacturing electronic circuits using 3D printing methods plays a prominent role in sensing applications and has achieved significant growth in recent years. This growth has led to the development of stretchable, flexible electronics and wearable electronics that are useful as sensing applications in the fields of real-time health monitoring systems. In this paper, a multiwalled carbon nanotube (MWCNT)-based electronic circuit was developed using the 3D printing technique called direct ink writing (DIW). Polyvinyl alcohol (PVA) was used as the binder material to make the MWCNT ink for printing. Different concentrations of MWCNT ink were prepared using 5, 10, and 15 wt. % PVA solutions. The viscosity of MWCNT inks was measured using a rheometer (cone and plate type). The ink exhibited shear thinning behavior, which is suitable for DIW. Finally, the printing of a designed electronic circuit was carried out using a pneumatic extrusion–based 3D printer. The strain sensor circuit—measuring 20 mm long, 9.2 mm wide, and 0.8 mm thick—is manufactured by the 3D printer. Electrical resistivity of strain sensor circuit is evaluated by adopting a two-probe method; the observed resistivity value was 1.7 × 10−2 Ωm for MWCNT ink made with 10 wt. % PVA solution and 1.97 × 10−2 Ωm for MWCNT ink made with 15 wt. % PVA solution.