Background: Knowing that magnesium (Mg) alloys and its composites bear the potential of being used simultaneously for light structural as well as biomedical applications, it appears prudent to look for developing a novel Mg alloy; the concurrent demand is to monitor recent trend in development of functional Mg-alloy and its composite materials through extensive patent search. Review of recent patents in the related field makes it relevant to investigate this aspect. Objective: The authors aim to study the evolution of structure and properties in stir cast of AZ- 61 alloy with minor additions of scandium, calcium and manganese. This paper reports the results of this investigation. Methods: The castings are prepared by stirring the molten alloy at 600 rpm for 10 minutes, followed by pouring into a preheated metal mould. The solidified alloys are homogenized at 550°C for 12 hours. The homogenized alloys are then subjected to solutionising treatment at 500°C for 5 hours; subsequently, the alloys are quenched in iced water. The quenched alloys are subjected to ageing treatment at different temperatures between 100°C to 400°C at an interval of 100°C. Similar experiments are conducted with its statically cast counterparts. The structure and properties of all the samples have been characterized by optical and scanning electron microscopy, and XRD analysis; DSC heating run is conducted to study the kinetics of phase transformation. Mechanical behaviour of castings is studied with the aid of tensile testing and fractography. Moreover, tribological behaviour of alloys is assessed by wear testing with the help of pin on disc method. Results: The results show that the stir cast alloy produces a homogeneous structure with significant improvement in properties. The precipitates of Mg17Al12, Al Mn, Mg Zn2, Al2 Ca and Mg2 Ca are formed due to the ageing of both stir cast and statically cast alloy. It is found that the diffusion of Al in magnesium controls the precipitation process. The tribological properties are found to be satisfactory for the stir cast alloy. Conclusion: The modified AZ61 alloy with minor additives, achieves excellent structural homogeneity and mechanical properties after stir casting followed by quench ageing.

Objective: The microstructure and mechanical properties of modified AZ 61 alloy -graphene composite (1wt. %, and 2wt. % graphene) were examined under various conditions of temperature of rolling, number of roll pass, and the amount of deformation. Method: The rolling operation was carried out in a laboratory scale rolling with the initial stock temperature of 4000C. The rolling temperatures were varied and kept at 3500C 3000C, and 2500C. After a few roll passes, the rolled stocks were reinserted within the furnace to make up for the temperature drop. The rolling was continued until the amount of thickness reduction reached 35%. The number of passes varied between 1-4. It was observed that the influence of rolling temperature was quite sensitive to the number of passes to reach the target deformation ~35%. Finding: The study on the structure and properties of hot rolled graphene-reinforced AZ-61 magnesium alloy with minor additions of scandium and calcium is scarce in the literature. Novelty: In the present investigation attempts are made to probe into the effect of graphene reinforcement in AZ-61 alloy that is compositionally modified by minor additions of scandium and calcium with the expectation of a higher level of strengthening. The results showed that maximum hardness values ranged with in 101HV to 106HV whereas, the maxima of tensile and yield strength were found to be 266 .82 MPa and 102 MPa at an elongation percent of 25%. By refining the microstructure, dynamic recrystallization enhanced the samples’ strength and ductility. AZ 61 graphene composite with minor additions of scandium and calcium achieves excellent structural homogeneity and mechanical properties after hot rolling with 2 wt. % graphene rolled at 3500C. Keywords: AZ61 Alloy; Rolling Temperature; Graphene; Composite; Tensile Strength; Deformation Percentage

This review provides a state-of-the-art and up-to-date analysis of the design and development of green monopropellant thrusters based on hydrogen peroxide (H₂O₂) and hydroxyl ammonium nitrate (HAN) as high-energy compounds for reaction control maneuvering of satellites. In summary, we introduce the new concept of Green Liquid Propellants (GLPs) that can serve as eco-friendly alternatives to conventional hydrazine thrusters. GLPs offer several advantages, including low toxicity, acceptable thermal decomposition and combustion behaviors, low onset temperatures of decomposition, stability, and long-term storability, compared to hydrazine. H₂O₂ exhibits a low onset temperature; however, its storability does not match that of hydrazine. On the other hand, HAN boasts excellent storability; however, it comes with a higher onset temperature when compared to hydrazine. This review provides critical insights into the recent advancements in H₂O₂ and HAN thrusters, along with an examination of the corresponding catalysts. The focus is on their application for the long-term maneuvering of satellites. We have chosen H₂O₂ and HAN formulations to focus on these two GLPs due to their extensive use by various space agencies worldwide. Moreover, the future directives of both selected green propellants were discussed for potential applications. Finally, the choice between H₂O₂ and HAN depends on the specific requirements of the propulsion system, taking into account factors such as performance, environmental impact, safety, and operational considerations. Each propellant has its advantages and challenges, and ongoing research aims to address some of the limitations associated with these green propellants.

Background: Solar cookers have been the subject of several theoretical and empirical investigations, with numerous modifications attempted to increase efficiency and security. Solar cookers need much sophisticated research and enhancement work to function better. A thorough grasp of the application of graphene in box-type solar cooking systems is crucial for both solar energy and graphene. Objective: To improve the performance of box-type solar cookers, this patent research aims to offer an experimental investigation and insightful information on of applying graphene coating to the absorber plate and its derivative. Materials and Methods: To ensure equal dispersion of graphene into the black paint, three samples containing (1, 3, and 5 wt%) of graphene embedded with the paint were produced with 1 mm, 3 mm, and 5 mm thickness of the coating and stirred at 400 rpm for two hours using a magnetic stirrer. X-ray diffraction and scanning electron microscopy have been studied to comprehend the influence of graphene nanoparticles on the surface morphology of the coated absorber panel. Performance evaluations of the box-type solar cookers were conducted with and without a graphene coating on the absorber plate, and data has been recorded for each case Results: The results of patent research show that the absorber plate with (1, 3, and 5 wt.%) of graphene embedded with black paint 1 mm, 3 mm, and 5 mm thickness coating has a maximum thermal efficiency of 41.48% with 97.08 W cooking power, 46% with 109.35 W cooking power, and 49% with 114.77 W cooking power for the average solar irradiation is 978 W/m2. Discussion: It was determined that the cooking power (P), the first figure of merit (F1), and the second figure of merit (F2) were all satisfactorily achieved. Embedding black paint into graphene coating has been shown to significantly influence the heat transmission and thermal performance enhancement of box-type solar cookers, as demonstrated by the findings of X-ray diffraction and Scanning Electron Microscopy analysis. Conclusion: The current research makes it abundantly evident that the incorporation of graphene into the absorber plate of a box-type solar cooker, together with the application of a black paint coating, leads to increased heat transfer rates, which in turn provides an increase in cooking power. Because of this, graphene is an attractive nanomaterial that has the potential to improve the performance of box-type solar cookers, which is the novelty of this research work.