Current Materials Science - Volume 16, Issue 2, 2023

The development of low-cost, high-efficiency electrode materials for supercapacitors is motivated by the growing need for green and affordable clean energy (SDG goal 7). Developing new energy conversion and storage technologies, such as supercapacitors, batteries, and fuel cells, is a viable option for meeting energy demands while addressing environmental concerns. Recent advances in carbonaceous materials derived from biowaste for supercapacitor applications have piqued the interest of academics and industry alike. Because of their large surface area and porous structure, activated carbon-based electrode materials can be used in various applications, including supercapacitors, fuel cells, and batteries. Carbonaceous materials such as carbon nanotubes, graphene, and activated carbon, exhibit EDLC-like behavior mainly due to ion adsorption at the electrode interface. In recent years, several potential strategies for the synthesis and structural architecture of biowaste-derived porous carbons have been tested with varying degrees of success. Thus, it is critical to evaluate the prospects for biowaste-derived porous carbon materials used as supercapacitor electrodes. In this review, we highlight how different biowaste-derived porous carbons affect the surface properties of carbon nanostructures and how this phenomenon affects their electrochemical performance. Additionally, the extent to which various biowastes have been utilized as porous carbon for supercapacitor electrodes is addressed. The different synthesis techniques, such as hydrothermal carbonization, physical activation, chemical activation, and microwave-assisted activation, are briefly described in this review. Finally, we highlight fabrication techniques as well as electrochemical performance measurements such as CV, GCD, EIS, energy density, and power density.

Additive manufacturing is a highly effective and versatile technology, especially in the medical sector, due to its customization, material complexity, design flexibility, waste minimization, and ability to fabricate intricate shapes that are cumbersome to manufacture by conventional manufacturing techniques. 4D printing plays a significant role in the medical field, especially in the areas not covered by 3D printing technologies, such as smart implants, devices and tools. Also, 4D printing helps doctors to treat more patients with high accuracy and quality. Hence, this manuscript aims to provide an overview of distinct 3D and 4D printing techniques and their emerging applications in the medical sector. A study of 3D printing technologies is presented by explaining the working principles of distinct 3D printing methods: stereo lithography, fusion deposition modeling, inkjet printing, selective laser sintering, selective laser melting and electron beam melting. In addition, the emerging applications of 3D printing in medical sectors (e.g., bioprinting, surgical guides, pharmaceuticals, prostheses, medical devices, dentistry, physiotherapy, etc.), as well as challenges and the future scope of 3D printing, are also discussed. Further, the concept of 4D printing, the market for both 3D and 4D printing, the benefits of 4D printing, the comparison of 3D and 4D printing, limitations, applications, and the future scope of 4D printing in the medical sector are also covered.

Recently, rare-earth activated phosphors have gained new and exciting applications in various fields, like display and illumination, phototherapy, plant growth, etc. The phosphorconverted white light emitting diode is prime in the art of solid-state lighting owing to its numerous merits, including desired spectral distribution, excellent chemical and thermal stability, high operational lifetime, reliability, and color quality of w-LEDs for lighting. The enhancement of the color gamut of backlight w-LEDs still needs to be addressed, which requires the design of high-efficient downshifting converter phosphors featuring thermally stable luminescence. The class of materials under suitable activation exhibit applications in a particular field. The emission in the UV region (312-315nm) is widely used for phototherapy lamps. Phototherapy has proven to be an excellent therapeutic option for the treatment of various types of skin diseases. Moreover, the emission corresponds to 600-750nm for plant cultivation. The present review article describes various rare-earth activated phosphors and their impact on human and plant physiology.

Paclitaxel (Taxol) is a drug that belongs to the class of compounds called Taxane. It is a strong and potent chemotherapeutic drug that inhibits the growth of certain types of cancer cells; however, its abundance is very low, and various types of methodologies have been implemented to extract paclitaxel from the bark of different plants and herbs. The molecularly imprinted polymers (MIPs) could be the best alternative to purify the paclitaxel molecule. MIPs have become an attractive solution for the selective and fine-tuned determination of target templates in complex forms where other comparable and relevant structural compounds could coexist. Implementation of quantum dots in MIPs improves their extraction features due to the presence of distinct functional sites. Quantum dots can be employed to modulate the size, detectability, and state of the imprinted materials, depending on the selected application. This review aims to summarize and illustrate the modern and innovative strategies based on the aggregation of MIPs with quantum dots. Quantum dot embedded MIPs can be exploited for simultaneous extraction, preconcentration, and detection of paclitaxel obtained from various sources.

Aims: This study aimed to investigate the molecular interactions of dextran as a solute with sodium hydroxide as a solvent. Background: The propagation of ultrasonic waves through solids and liquids offers vital information on the structure of solids and liquids. The molecular interaction in pure liquids and liquid solutions has also been explored using ultrasonic speed estimates. The ultrasonic speed in a fluid provides a cutting-edge, feasible, and trustworthy technique for examining the characteristics of the polymer, amino acid, carbohydrate, and vitamin arrangements, among other things. It is mainly connected to the binding capacities of particles or molecules and has been successfully used in comprehending the concept of molecular interaction in liquid solution. Ultrasonic velocity measurement allows for the precise evaluation of several relevant acoustical characteristics that are particularly sensitive to molecular interactions. Objective: The acoustic and thermodynamic characteristics were utilised to investigate different types of interactions, molecular motion, and different interaction modes and their effects, which were impacted by the size of the pure component and the mixes. The significance provides subjective data on the nature and quality of particle interactions between solute and solvent in liquid solutions. Acoustic characteristics are important for evaluating the effect of temperature and frequency on the polymer dextran's aqueous sodium hydroxide solvent interactions. The density (ρ), viscosity, and ultrasonic speed (η) at 303 K, 308K, 313 K, 318K and 323K have been measured in the systems of polymer dextran with aqueous sodium hydroxide solution by using a pycnometer, Ostwald viscometer, and ultrasonic interferometer at frequencies at 1MHz, 5MHz, 9MHz, 12MHz, respectively. The acoustic parameters, such as free volume, internal pressure, attenuation coefficient, Rao’s constant, and Wada’s constant, are determined using the experimental parameters, including density (ρ), viscosity (η), and ultrasonic speed (U). Methods: In this study, a pycnometer, an Ostwald's viscometer, and an ultrasonic interferometer to measure the density, viscosity, and ultrasonic velocity of the solution and compute the thermoacoustic parameters based on the measured parameters were used. Results: Ultrasonic wave propagation affects the physical characteristics of the medium, providing information about liquid and solution. Conclusion: The effect of frequency and temperature on thermo-acoustic properties was studied. The aforementioned research has interpreted the nature of forces between molecules, such as hydrogen bonds, charge transfer complexes, and the breakdown of hydrogen bonds and complexes. Intermolecular forces are weak (electrostatic forces between charged particles having a permanent dipole and molecules with induced dipoles). The geometrical fitting of one molecule into another, owing to the variation in shape and size of the molecules, results in structural properties of the components. Other: In recent years, advances in ultrasonic methods have made them a potent instrument for assessing knowledge about the physical and chemical behaviour of liquid molecules. Due to its versatile pharmaceutical, biological, and contemporary uses, it has drawn analysts' attention to a new area of investigation. Consistent data on the physical and chemical characteristics of a wide range of liquid solutions are required.

Background: Wearing is a prominent problem in friction stir welding. The material flow stress equation is a key factor that decides the accuracy of the simulation of the wearing process. Objective: We aim to propose a material flow stress equation based on material true stress and true strain curve, which takes proper factors into account and leads to good accuracy in numerical simulation of stir tool wear. Methods: The value of the material temperature rise caused by the material deformation heat and the value of the effect caused by the temperature rise on flow stress was calculated, and the effect value was used to modify the material flow stress and the related curve, and then the modified flow stress equation was obtained. On this basis, the equation was used to simulate the stir tool wear, and the simulation results were compared with those results without considering the effect of temperature rise. Results & Discussion: the wear amount of the stir needle when considering the effect of temperature rise is significantly less than that when the effect of temperature rise is not considered. Conclusion: In the simulation of the wear of the stir tool, it is necessary to adopt the modified flow stress equation considering the effect of temperature rise.