Current Materials Science - Volume 17, Issue 3, 2024

Powder Bed Fusion (PBF) is one of the earliest, most versatile, and popular AM processes, being well-suited for a great variety of materials. As in many other manufacturing processes, porosity is a phenomenon inevitably present in parts made by PBF. The quantity, shape, and distribution of pores, and the propensity to their formation depend strongly upon the type of process and on the processing conditions used to produce the part. It is well known that porosity influences in a dramatic way the quality and reliability of the manufactured materials and, therefore, it deserves special attention. In this paper, porosity and the more appropriate experimental techniques for detecting and measuring porosity are reviewed. Moreover, a comparison among the results obtained by applying different methodologies to measure the porosity of parts produced by Powder Bed Fusion is reported. The final purpose of the work is to provide the reader with the tools for the correct choice of the most suitable method for measuring the porosity of additively manufactured pieces.

Objective: This article highlights the applications of nanotechnology in the detection of explosives. Evidence Acquisition: The increasing rise in terrorist acts throughout the globe has brought attention to the significance of locating hidden bombs and motivated new propelled breakthroughs to ensure public safety. Recognizing explosives and closely related-threatening combinations has already risen to the top of the priority list for contemporary national security and counterterrorism applications. Sensors based on nanotechnology have a fair probability of fulfilling all the criteria needed to be a practical solution for explosive trace detection. Results: Nanowire/nanotube, nanomechanical devices, and electronic noses are three nanosensor technologies that have the most potential to develop into commercially viable technology platforms for the detection of trace explosives. Certain functionalized nanoparticles can exhibit different behaviors as a result of unique interactions with nitroaromatics. Semiconducting singlewalled carbon nanotubes (SWCNT) have been used as wearable chemical sensors. Conclusion: In this paper, the potential of nanosensors has been exposed that can be used to build a sensor system with high selectivity and sensitivity and appropriate platforms for signal transduction for the detection of explosives.

Biomaterials, a fascinating and highly interdisciplinary field, have become integral to improving modern man's conditions and quality of life. It is done by many health-related problems arising from many sources. The first batch of biomaterials was produced as implants and medical equipment in the 1960s and 1970s. Biomaterials are primarily used in medicine and may be directly or indirectly exposed to biological systems. For instance, we could use them in cultures and mediums for cell development, plasma protein testing, biomolecular processing cultures, diagnostic gene chips, and packaging materials primarily for medical items. Biomaterials should have certain qualities for human-related problems, like being non-carcinogenic, not being pyrogenic or toxic, completely plasma compatible, and anti-inflammatory. This paper introduces the history, classification, and ideal parameters of biomaterials and where they are used in the current scenarios in the medical field, providing a brief outlook on the future.

In cement-based composites, carbon nanotubes (CNTs) and carbon nano fibres (CNFs) can act as crack bridging, delaying the development of nano fractures into microcracks. Recent research on the use of CNTs and CNFs in cement-based composites was reviewed in this paper. Earlier studies have demonstrated that cement-based composites reinforced with CNTs/CNFs have lower porosities and superior mechanical properties to plain cement-based composites. Using CNTs or CNFs in cement-based composites presents challenges due to their low matrix dispersion and weak interfacial contact. Some projected future investigations were indicated.

Background: The researchers are in the situation to satisfy the demand for engineering materials by developing novel eco-friendly materials. The natural fiber composites are the substitutes for the synthetic material. Introduction: The mechanical properties of curaua fiber-reinforced polyester (CFRP) composites were investigated, as well as the effects of curaua fibre infusion with Babool Wood particles (BWP). Methods: The composite specimens were fabricated using a hand lay-up approach using varying amounts of curaua fibres (CF) and babool wood particles in a 1:1 ratio in order to test the tensile strength and flexural strength. Results: The results demonstrated that before weakening, the tensile strength and flexural strength of the composite samples rose by up to 40% for hybrid reinforcements. Comparing samples made of pure resin to those made of the composite at 40 weight percent (CF20/BWP20), the tensile and bending strengths of the composite are improved by 93.42% and 86.4%, respectively. Conclusion: The tensile and flexural modulus values of the hybrid composites increased by up to 50% fiber, but less successfully (CF25 and BWP25). The fracture mechanism of the shattered composite samples was examined using scanning electron microscopy.

Background: Existing reinforced concrete (RC) structures can deteriorate over time due to aging, poor construction design, natural disasters, etc. In recent years, fiber-reinforced polymer (FRP) composite materials are becoming a preferred choice for concrete construction repair due to their durability, high strength, and corrosion resistance. This study aimed to study and analyze the properties of the constituent materials to identify any weaknesses and potential improvements. Methods: The present study investigated the effectiveness of flexural strengthening of RC beams using a hybrid grouping of glass-FRP (GFRP) and carbon-FRP (CFRP) unidirectional laminates. ANSYS finite element analysis (FE) software was used to investigate the failure modes of the beams and the stress-strain parameters. The impact of adopting two different grades of reinforcing bars in RC beam modeling was also contrasted in the study. Results: Comparisons between the finite element analysis and experimental literature results were made. Based on the test findings, it could be concluded that retrofitted beams perform better than non-retrofitted beams. According to experimental results, the HY14 sheet enhanced beam had a 188.46% higher ultimate load than the unenhanced beams. Conclusion: Comparing experimental findings to the conclusions of the numerical analysis, a maximum difference of ultimate load and deflection at mid-span of 3.40% and 4.91%, respectively, were used to assess the accuracy of the results.

Introductions: TiO2 nanoparticles ceramic (NPs) codoped with Bi and W ions have been synthesized by a hydrothermal technique. A portion of the prepared ceramic was posthydrogenated. Ceramic NPs were characterized by traditional methods. Crystalline structures and optical properties were investigated using X-Ray diffraction (XRD) and diffuse reflection spectroscopy, respectively. Methods: The present work has focused on the creation of a colossal (giant) dielectric permittivity (GP) behavior with the TiO2 host NCs through the Bi/W codoping to construct electronic core/shell structures. In addition, the influence of post-hydrogenation on the created GP was also examined. Results: It was found a high permittivity of 3.69×10⁴ at 1 kHz, which was reduced to 3.29×10⁴ by the hydrogenation of the sample. This is attributed to the densification of the itinerant electrons by the effect of the catalytic power of the doping W⁵⁺ ions to dissociate the adsorbed H2. Conclusion: The present values of GP are much higher than the permittivity of the pure TiO2 and the Bi-doped TiO2 ceramic, which was attributed to the construction of core/shell electronics structures. As a result, the doping process has been studied in detail in relation to scientific expectations.