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Abstract: Presently, scientists and researchers are in an endless quest to develop green, recyclable, and eco-friendly materials. Natural fibre reinforced polymer composites became popular among materialists due to their lightweight, high strength-to-weight ratio, and biodegradability. However, all-natural fibre reinforced polymer composites are not biodegradable. Polymer matrices like poly-lactic acid (PLA) and poly-butylene succinate (PBS) are biodegradable, whereas epoxy, polypropylene, and polystyrene are non-biodegradable polymer matrices. Besides biodegradability, PLA has been known for its excellent physical and mechanical properties. This review emphasises the mechanical properties (tensile, flexural, and impact strengths) of natural fibrereinforced PLA composites. Factors affecting the mechanical properties of PLA composites are also discussed. It also unveils research gaps from the previous literature, which shows that limited studies are reported based on modeling and prediction of mechanical properties of hybrid PLA composites reinforcing natural fibres like abaca, aloe vera, and bamboo fibres.

High entropy alloys (HEAs) have become the most popular among the materials scientists and researchers due to their attributes like high strength, hardness and corrosion resistance when compared to conventional alloys. For sprawling use of HEAs in various domains such as aerospace, structural and automobile, it is necessary for researchers to explore more number of HEAs. In this endless endeavour of exploration, researchers have also developed refractory HEAs which possess better mechanical properties when compared to conventional HEAs. But, HEAs (without refractory elements) are more economical than refractory HEAs. This is due to the fact that most of the refractory elements are expensive. The present work focuses on the effect of refractory elements, namely, Mo, W, Ta, Nb, Ti and V on mechanical properties of HEAs. This review also provides an insight into the phase evolution in HEAs due to addition of refractory elements. Moreover, it also unfolds research gaps from past literature, which shows that there is scarcity of literature on dynamic characteristics, fatigue and creep analysis of Hf, Zr, Si and Cr based HEAs.

In the Chhattisgarh state of India, the Bastar region is famous for its various forest produce collected by local inhabitants. These collected forest produce are dried in open sun drying. This chapter presents the design and analysis of solar dryer which is simple in construction and a low-cost dryer. The construction of the solar dryer will be made of galvanized mild steel sheet absorbing the sun's radiation. The hot air will be taken out through a wind turbine ventilator at the top to maintain the required humidity level in the solar dryer. The analysis shows that the temperature inside the solar dryer is evenly distributed. The suggested solar dryer will reduce the drying time of the forest produce.

High-entropy alloys are a new class of material. In recent past, high-entropy alloys have attracted a great deal of attention from researchers due to their unique multi-element solid-solution structures and excellent properties. This paper deals with a new promising class of high entropy alloys synthesized through mechanical alloying for 15 h. The elemental powders are milled in high energy ball milling. The elemental powders are taken out at particular time intervals for the phase analysis through X-ray diffractometer. The particle morphology was scrutinized by Scanning electron microscopy. The phase analysis through X-ray diffractometer reveals the formation of face-centered cubic phase along with some Ni-Si based compounds after 15 h of mechanical alloying. An increase in crystallite size is observed with increase in milling time whereas, a decrement in lattice strain is observed with advancing milling time. To support the lattice strain increment, the dislocation density is also calculated by using the variance method. The high negative mixing enthalpy of Si and Ni results into the formation of Ni-Si based compound.

The alternator is the most essential equipment in an automobile to charge the battery. A modern vehicle is fitted with new accessories which run on the battery. Hence the health of battery is very important in new vehicles. This research paper gives a detailed study of maintenance of alternator and also suggests an alternator tester which is handy and very useful equipment for Alternator testing.

The low-pressure gas welding is very popular in sheet welding. The small automobile garages, body repairing workshops used this type of welding extensively in India. This research paper focused on the study of the construction and operation of popular acetylene gas generators models used in low-pressure welding. After studying on different parameters the authors found that prefabricated or readymade generators are found best for safe operational uses after comparing them on different parameters with fabricated generators. The authors firmly believe that the existing fabricated acetylene generators must be changed with a prefabricated model to improve the quality of the weld and safe welding practices.

This paper explores the impact of Si addition on the microstructural evolution and mechanical properties of AlCoCrCuFeNiSix (x = 0.3 and 0.6 at. ratio) alloys synthesised by spark plasma sintering of mixed powders. X-ray diffraction technique is implemented for phase formation analysis of the present high entropy alloys. The AlCoCrCuFeNi HEA with Si = 0.3 content shows the evolution of duplex phase of FCC and BCC whereas, with further increase in Si = 0.6 content, the sigma phase appeared along with the BCC and FCC phases. Increased hardness and wear resistance with increased Si element can be attributed to the development of the BCC and sigma phase along with solid solution strengthening. As Si has smaller atomic radius contrasted with the other constituent components in the blend, it decreases the mobility of dislocations, increment the strain energy, and consequently improve the solid-solution strengthening effect.

In this work, the effect of addition of Si on the phase evolution and mechanical properties of AlCoCrCuFeNiSix alloy system has been studied. The High Entropy Alloys (x = 0 and 0.9) have been synthesised by powder metallurgy route which includes mechanical alloying (MA) and spark plasma sintering. X-ray diffraction technique was performed to understand the alloying behaviour and to investigate the phase formation of the high entropy alloys. The samples after spark plasma sintering comprised mainly of body centered cubic structured phase with a small extent of face centered cubic structured phase. With the addition of silicon, the XRD peak intensity of body centered cubic appears strong compared to the face centered cubic structured phase. Moreover, no intermetallic is observed in AlCoCrCuFeNi high entropy alloy system. However, further accumulation of Silicon results in the evolution of sigma (σ) phase.

Herein Tb3+ (0.1, 0.2, 0.5, 1, 1.5, 2 and 2.5 mol %) doped Y4Al2O9 (monoclinic phase of yttrium aluminium oxide Y/Al 2:1) phosphors have been synthesized by conventional modified solid state reaction method (CMSSRM) using inorganic materials like Yttrium Oxide (Y2O3), Aluminium Oxide (Al2O3), Terbium Oxide (Tb2O3) and boric acid as a flux. The prepared phosphor samples were characterized using X-ray diffraction analysis (XRD), photoluminescence (PL), and thermoluminescence (TL) glow curve. From the XRD data, using the Scherrer formula the calculated average crystallite size of Tb3+ doped Y4Al2O9 phosphor is around 235 nm. Photoluminescence excitation spectra show sharp excitation peak centred at 270 nm and broad excitation peak centred at 300 nm which is due to charge transfer band. Here emission spectra show three distinct peaks centred at 492 nm (5D4 → 7F7), 544 nm (5D4 → 7F6) and 584 nm (5D4 → 7F4). Results indicate that PL intensity increases with increasing the concentration of doping ion i.e. Tb3+ up-to 2 mol % after that due to concentration quenching PL intensity decreases. Commission Internationale de l'Eclairage (CIE) values were calculated as X = 0.24 and Y = 0.56 and it shows intense green emission. TL glow curves were analysed with effect of doping ion concentration and effect of variable UV exposure time. Kinetic parameters were calculated using various methods proposed by Chen and others.

The upconversion (UC) of the rare earth doped MY2O4 (M=Ba, Sr, Ca) has been extensively investigated due to their potential applications in many fields, such as color display, high density memories, optical data storage, sensor and energy solar cell, etc. Many series of them, especially the Er3+, Yb3+ doped MY2O4 were studied in this chapter, due to the thermal and mechanical toughness, high optical transmittance from the ultraviolet to the infrared regions, and a low nonlinear refractive index compared to the other commercial laser glasses. The energy transfer (ET) mechanism of rare earth doped phosphor plays an important role in the upconversion process.

In today’s global scenario of intense competition and environmental uncertainty flexibility in supply chain has an important role to play for the existence of any supply chain business. A need to be responsive to the constantly changing market scenario and cater to the customer needs, a certain degree of flexibility is required, which requires the coordination of many plants to produce and deliver goods to customers located in different places, and suppliers, which provide each plant with the required components. This paper intends to measure the degree of flexibility required for a two stage supply chain and assessing both the supplier flexibility and the assembler flexibility. In this paper, nine configurations of the SC are considered resulting from the combination of the three degrees of supplier and manufacturer flexibility, i.e. no flexibility, limited flexibility and total flexibility, respectively. Simulation model representing the different flexibility configurations are evaluated and the performance of each configuration analyzed to determine the flexibility configuration suitable to a supply chain. In particular the performance analysis of lead time, work-in-process, service level and cost are measured to determine the suitable flexibility.

Today, there is an increasing demand worldwide for the advanced materials in order to obtain the desired properties. This is because a single material generally cannot meet the requirement of harsh engineering environment that is why the need for composites arises. Metal matrix composite is an important class of materials with high potential for structural applications requiring high specific modulus, strength and toughness. Metal matrix composites with unique properties are growing every day and widely used in different industries because of their high mechanical properties and wear resistance.