Materials Science Research Articles

Current developments in elastic and acoustic metamaterials science.

The concept of metamaterial recently emerged as a new frontier of scientific research, encompassing physics, materials science and engineering. In a broad sense, a metamaterial indicates an engineered material with exotic properties not found in nature, obtained by appropriate architecture either at macro-scale or at micro-/nano-scales. The architecture of metamaterials can be tailored to open unforeseen opportunities for mechanical and acoustic applications, as demonstrated by an impressive and increasing number of studies. Building on this knowledge, this theme issue aims to gather cutting-edge theoretical, computational and experimental studies on elastic and acoustic metamaterials, with the purpose of offering a wide perspective on recent achievements and future challenges. This article is part of the theme issue 'Current developments in elastic and acoustic metamaterials science (Part 1)'.

A review of advanced helical fibers: formation mechanism, preparation, properties, and applications.

As a unique structural form, helical structures have a wide range of application prospects. In the field of biology, helical structures are essential for the function of biological macromolecules such as proteins, so the study of helical structures can help to deeply understand life phenomena and develop new biotechnology. In materials science, helical structures can give rise to special physical and chemical properties, such as in the case of spiral nanotubes, helical fibers, etc., which are expected to be used in energy, environment, medical and other fields. The helical structure also has unique charm and application value in the fields of aesthetics and architecture. In addition, helical fibers have attracted a lot of attention because of their tendrils' vascular geometry and indispensable structural properties. In this paper, the development of helical fibers is briefly reviewed from the aspects of mechanism, synthesis process and application. Due to their good chemical and physical properties, helical fibers have a good application prospect in many fields. Potential problems and future opportunities for helical fibers are also presented for future studies.

On the glow of cremated remains: long-lived green photo-luminescence of heat-treated human bones.

The long-lived green luminescence of human bone (that has been heated to 600°C for a short duration) is attributed to a carbon quantum dot material (derived from collagen) encapsulated and protected by an inorganic matrix (derived from bone apatite) and is more intense in dense rigid and crystalline parts of (healthy) human bones. The strong collagen-apatite interaction results (upon decomposition) in a protective inorganic environment of the luminescent centers allowing long-lived triplet-based emission of a carbon (quantum) dot-like material at room temperature, as well as resilience against oxidation between 550 and 650°C. The graphitic black phase (obtained upon heating around 400°C) is a precursor to the luminescent carbon-based material, that is strongly interacting with the crystalline inorganic matrix. Human bone samples that have been heated to 600°C were subjected to steady-state and time-resolved spectroscopy. Excitation-emission matrix (EEM) luminescence spectroscopy revealed a broad range of excitation and emission wavelengths, indicating a heterogeneous system with a broad density of emissive states. The effect of low temperature on the heat-treated bone was studied with Cryogenic Steady State Luminescence Spectroscopy. Cooling the bone to 80K leads to a slight increase in total emission intensity as well as an intensity increase towards to red part of the spectrum, incompatible with a defect state model displaying luminescent charge recombination in the inorganic matrix. Time-resolved spectroscopy with an Optical Multichannel Analyzer (OMA) and Time Correlated Single Photon Counting (TCSPC) of these samples showed that the decay could be fitted with a multi-exponential decay model as well as with second-order decay kinetics. Confocal Microscopy revealed distinct (plywood type) structures in the bone and high intensity-fast decay areas as well as a spatially heterogeneous distribution of green and (fewer) red emissive species. The use of the ATTO 565 dye aided in bone-structure visualization by chemical adsorption. Conceptually our data interpretation corresponds to previous reports from the material science field on luminescent powders.

Analisis Risiko Modal Ventura Syariah di Indonesia

Venture capital as an alternative financing outside credit banking. Investments made in the form of shares or convertible bonds in the long term, and aimed at business partner companies (PPU), venture capital is a collection of capital originating from investors to be managed professionally by a management company and investment in PPU. Funds invested in venture capital are investment funds that have high risk. This research uses a library or literary study approach. Data collection techniques are carried out through reading and taking notes, as well as managing previous research materials. The aim of this research is to determine the potential risks that will occur and the impact of risks on venture capital. Research results show that venture capital often contributes to helping entrepreneurs develop. So it cannot be denied that venture capital is very prone to losses for both parties.

Thermographic study of freezing water drops: An insight on Mpemba effect

Despite decades of research, the Mpemba Effect challenges scientists, prompting further investigation and refinement of existing hypotheses. This work uses optical tools such as thermography to analyze and study the Mpemba effect on drops. We analyze times and contact angle changes with temperature with an easily controlled experiment. This work contributes to the ongoing discourse surrounding the Mpemba Effect, emphasizing the need for interdisciplinary collaboration and experimental rigor to unravel the complexities of this intriguing phenomenon. A deeper understanding of the Mpemba Effect enhances our knowledge of thermodynamics and fluid dynamics and opens avenues for practical applications in fields such as cryopreservation, meteorology, and materials science.

Theoretical study of solidification phase change heat and mass transfer with thermal resistance and convection subjected to a time-dependent boundary condition

The solidification of phase-change materials (PCMs) is a key process that occurs commonly in materials science and metallurgy, such as in the casting of alloys and energy management systems. There is a lot of literature in this area that assumes the PCMs are in close contact with the heat source or sink. However, a non-freezing wall frequently encloses them in practical situations. This work presents a phase change problem that describes the solidification of a semi-infinite PCM with thermal resistance. We assume that time-dependent heat flux drives the solidification process. The PCM first convert into mush and then into solid, which leads to a three-region problem. The current study accounts for both conduction as well as convection heat transfer mechanisms. Unfortunately, the exact solution to such problems with time-dependent flux-type boundary conditions may not be possible. Thus, there is considerable interest in deriving the analytical solution. The space–time transformation yields the analytical solution to the problem. A numerical example of Al−Cu alloy with 5%Cu is presented to demonstrate the current study. Thermal resistance shows a pronounced impact on the temperature field. Lower thermal resistance offers faster solidification rate. It is found that as the heat transfer constant increases, the rate of propagation of solid-mush and mush-solid interfaces gets enhanced. In addition, the growth of thermal resistance is of linear nature, with variation in the value of Q. The solidified region has higher concentration than the mush region. The current study is applicable to both eutectic systems and solid solution alloys.

Engineered moiré photonic and phononic superlattices.

Recent discoveries of Mott insulating and unconventional superconducting states in twisted bilayer graphene with moiré superlattices have not only reshaped the landscape of 'twistronics' but also sparked the rapidly growing fields of moiré photonic and phononic structures. These innovative moiré structures have opened new routes of exploration for classical wave physics, leading to intriguing phenomena and robust control of electromagnetic and mechanical waves. Drawing inspiration from the success of twisted bilayer graphene, this Perspective describes an overarching framework of the emerging moiré photonic and phononic structures that promise novel classical wave devices. We begin with the fundamentals of moiré superlattices, before highlighting recent studies that exploit twist angle and interlayer coupling as new ingredients with which to engineer and tailor the band structures and effective material properties of photonic and phononic structures. Finally, we discuss the future directions and prospects of this emerging area in materials science and wave physics.

Nonlinear physics of moiré superlattices.

Nonlinear physics is one of the most important research fields in modern physics and materials science. It offers an unprecedented paradigm for exploring many fascinating physical phenomena and realizing diverse cutting-edge applications inconceivable in the framework of linear processes. Here we review the recent theoretical and experimental progress concerning the nonlinear physics of synthetic quantum moiré superlattices. We focus on the emerging nonlinear electronic, optical and optoelectronic properties of moiré superlattices, including but not limited to the nonlinear anomalous Hall effect, dynamically twistable harmonic generation, nonlinear optical chirality, ultralow-power-threshold optical solitons and spontaneous photogalvanic effect. We also present our perspectives on the future opportunities and challenges in this rapidly progressing field, and highlight the implications for advances in both fundamental physics and technological innovations.

An Insight into Biodegradable Polymers and their Biomedical Applications for Wound Healing.

Biodegradable polymers, encompassing both natural and synthetic polymers, have demonstrated efficacy as carriers for synthetic drugs, natural bioactive molecules, and inorganic metals. This is due to their ability to control the release of these substances. As a result, various advanced materials, such as nanoparticle-loaded hydrogels, nanofibrous scaffolds, and nanocomposites, have been developed. These materials have shown promise in enhancing processes, such as cell proliferation, vascular angiogenesis, hair growth, and wound healing management. Natural polymers, including hyaluronic acid, collagen, chitosan, gelatin, and alginate, as well as synthetic polymers like polylactic acid, polyglycolic acid, polylactic co-glycolic acid, and PCA, have significant potential for promoting wound healing. This study examines the advancements in biodegradable polymers for wound healing, specifically focusing on each polymer and its distinctive formulations. It also discusses the in-vitro experiments conducted using different cell lines, as well as the in-vivo studies that explore the numerous uses of these polymers in wound healing. The discussion also included the exploration of modifications or combinations of several polymers, as well as surface changes, in order to produce synergistic effects and address the limitations of individual polymers. The goal was to expedite the healing process of different chronic wounds. Due to this, there have been notable advancements in the technological use of polymeric mixes, including biodegradable polymer-based scaffolds, which have accelerated the process of wound healing.

Revitalizing Indonesia’s Sugar Industry: Unveiling the Potential of Sago as a Catalyst for National Sugar Self Sufficiency in the Future

Sago, the other source of sugar production need to be pursued in Indonesia, as Indonesia is highly dependent on sugar cane. This study aimed to analyze the production of liquid sugar based on sago by enzymatic method. The characteristics of liquid sugar made from sago has met with the standard provisions of Indonesian National Standard (SNI 01-2978992) except for the parameter of color. However, the color of sago liquid sugar is acceptable to consumers and market. The liquid sugar produced from sago could reach 0.6 to 0.8 liters per kg. If the sago is obtained from around 50,000 hectares of sago plantations and converted into liquid sugar, then around 600,000 kiloliters of sugar will be produced, or equivalent to 27% of the total national sugar production. The feasibility study showed that the sago liquid sugar business was profitable, which might be seen from the BCR value of 1.16, NPV Rp 58,754,955.64, PBP of 2 years 11 months, and IRR of 34.73%. Even though sago has a great potential, but the development still faces various problems such as unproper sago cultivation, difficulty to access sago land, limited mastery of farmer technology, and unestablished farmer institutions.

Machine Learning for Predicting Ultralow Thermal Conductivity and High ZT in Complex Thermoelectric Materials.

Efficient and precise calculations of thermal transport properties and figures of merit, alongside a deep comprehension of thermal transport mechanisms, are essential for the practical utilization of advanced thermoelectric materials. In this study, we explore the microscopic processes governing thermal transport in the distinguished crystalline material Tl9SbTe6 by integrating a unified thermal transport theory with machine learning-assisted self-consistent phonon calculations. Leveraging machine learning potentials, we expedite the analysis of phonon energy shifts, higher-order scattering mechanisms, and thermal conductivity arising from various contributing factors, such as population and coherence channels. Our finding unveils an exceptionally low thermal conductivity of 0.31 W m-1 K-1 at room temperature, a result that closely correlates with experimental observations. Notably, we observe that the off-diagonal terms of heat flux operators play a significant role in shaping the overall lattice thermal conductivity of Tl9SbTe6, where the ultralow thermal conductivity resembles that of glass due to limited group velocities. Furthermore, we achieve a maximum ZT value of 3.17 in the c-axis orientation for p-type Tl9SbTe6 at 600 K and an optimal ZT value of 2.26 in the a-axis and b-axis direction for n-type Tl9SbTe6 at 500 K. The crystalline Tl9SbTe6 not only showcases remarkable thermal insulation but also demonstrates impressive electrical properties owing to the dual-degeneracy phenomenon within its valence band. These results not only elucidate the underlying reasons for the exceptional thermoelectric performance of Tl9SbTe6 but also suggest potential avenues for further experimental exploration.

Effect of the Glass Fiber Orientation on Mechanical Performance of Epoxy based Composites

Composites are one of the most advanced and adaptable engineering materials. The strength of any composite depends upon volume/weight fraction of reinforcement, orientation angle and other factors. The present work focuses on the determination of the mechanical properties of pure epoxy and unidirectional glass fiber reinforced epoxy. Nowadays, glass fibers are being used in several engineering applications like electronics, aviation, automobile, sport industry etc. Glass fibers are having excellent properties like high strength, flexibility, stiffness, and resistance to chemical attack. With an increase in the content of unidirectional glass fiber volume the properties of unidirectional glass Fiber Reinforcement Polymer (GFRP) composite were improved. It may be used in different forms like chopped, woven mat, short fibers and long fibers etc. Each type of glass fiber has unique properties and is used for different applications. The mechanical and thermal properties of various polymer composites reinforced with glass fibers when subjected to mechanical loading have been studied and reported.

Corrigendum to “Effect of Nd-Y co-substitution on structural, magnetic, optical and microwave properties of NiCuZn nanospinel ferrites” Journal of Materials Research and Technology, Volume 9, Issue 5, September–October 2020, Pages 11278-11290

Corrigendum to “Effect of Nd-Y co-substitution on structural, magnetic, optical and microwave properties of NiCuZn nanospinel ferrites” Journal of Materials Research and Technology, Volume 9, Issue 5, September–October 2020, Pages 11278-11290

The effect of A-site cations on charge-carrier mobility in Fe-rich amphiboles

Abstract Elucidating the high-temperature behavior of rock-forming minerals such as amphiboles (AB2C5 T8O22W2) is critical for the understanding of large-scale geological processes in the lithosphere and, in particular, the development of high conductivity in the Earth’s interior. Recently, we have shown that at elevated temperatures, CFe-bearing amphiboles with a vacant A site develop two types of charge carriers: (1) small polarons and (2) delocalized H+ ions. To elucidate the effect of A-site cations on the formation and stability of charge carriers within the amphibole structure, here we analyzed synthetic potassic-ferro-richterite as a model Fe-rich amphibole with a fully occupied A site via in situ temperature-dependent Raman spectroscopy. We further compare the results from in situ time-dependent Raman-scattering experiments on pre-heated and rapidly quenched potassic-ferro-richterite and riebeckite as a model Fe-rich amphibole with a vacant A site. We show that the presence of A-site cations (1) reduces the activation temperature of mobile polarons and delocalized H+ cations; (2) decreases the magnitude of the polaron dipole moment; (3) slows down the process of re-localization of electrons on cooling; and (4) makes the electrons inert to rapid change in external conditions, supporting the persistence of a metastable state of pre-activated delocalized electrons even at room temperature. Our results have important geological implications demonstrating that the A-site cations may control the depth of development of high conductivity in subducted amphibole-bearing rocks. Moreover, from the viewpoint of mineral-inspired materials science, our results suggest that the amphibole-structure type has great potential for designing functional materials with tunable anisotropic-conductivity properties.

“Fast-charging” mechanism of Li3VO4 from the perspective of material science for lithium-ion battery

“Fast-charging” mechanism of Li3VO4 from the perspective of material science for lithium-ion battery

Utilizing a layer-by-layer self-assembly strategy to construct eco-friendly and sustainable superhydrophobic C-S@PDMS@SiO2 coatings on engineering materials for efficient oil-water separation

Utilizing a layer-by-layer self-assembly strategy to construct eco-friendly and sustainable superhydrophobic C-S@PDMS@SiO2 coatings on engineering materials for efficient oil-water separation

Ceramic/Polymer Nanodielectrics: Towards a Multifunctional or Smart Performance

Ceramic nanoparticles/polymer composite nanodielectrics constitute a novel class of engineering materials, which exhibit tunable mechanical, thermal, electrical and magnetic properties, energy storing/recovering ability in tandem with processability and corrosion resistance. By these means the produced nanocomposites are characterized by multifunctionality since structural components are able to perform a wide range of desirable functions. When the embedded nanoparticles are polar oxides and/or piezo/ferro-electrics, or any kind of stimuli responsive materials additional functional performance is induced in the nanocomposites, providing a suitable basis for the development of smart materials.

Enhancing electrochemical performance of sodium-ion batteries: Optimal Ca2+ doping in O3-NaNi0.33Mn0.33Fe0.33O2 layered oxide cathode materials

Current sodium-ion battery technologies are hindered by limitations in cathode material performance, including insufficient cycle stability and low energy density, which impede their wider application and competitiveness with lithium-ion counterparts. Addressing these challenges requires innovative material engineering to improve electrochemical properties and operational durability. In this study, we synthesized a series of Na1-2xCax(Ni0.33Mn0.33Fe0.33)O2 (x = 0, 0.015, 0.025, 0.04, 0.05), by doping with electrochemically inactive Ca2+. Our findings demonstrate that doping with Ca2+ significantly enhances the electrochemical performance, as evidenced by comparisons with undoped materials. Specifically, the material Na0.95Ca0.025(Ni0.33Mn0.33Fe0.33)O2, synthesized at 900 °C, showed the best electrochemical performance, achieving an initial discharge specific capacity of 137 mAh/g within a voltage range of 2–4 V, maintaining a capacity of 117 mAh/g at a 5C discharge rate, and exhibiting a capacity retention rate of 96.2 % after 50 cycles at 1C. Additionally, Ca2+ doping was found to enhance the air stability, with negligible change in initial discharge capacity after exposure to air for 24 and 72 h. This doping strategy not only improves the performance of sodium-ion batteries but also supports the development of high-energy–density industrial batteries, offering a viable approach to designing other layered oxide materials.

A Comprehensive Review: Versatile Imaging Probe Based on Chemical Materials for Biomedical Applications.

Imaging probe and contrast agents play significant role in combating cancer. Based on special chemical materials, imaging probe can convert cancer symptoms into information-rich images with high sensitivity and signal amplification, accompanying with detection, diagnosis, drug delivery and treatment. In the paper, some inorganic and organic chemical materials as imaging probe, including Ultrasound imaging (US), Optical imaging (OP), Photoacoustic imaging (PA), X-ray Computed Tomography (CT), Magnetic Resonance imaging (MRI), Radionuclide imaging (RNI) probe, as well as multi-modality imaging probe for diagnosis and therapy of tumour were introduced. The sophisticated and comprehensive chemical materials as imaging probe were highlighted in detail. Meanwhile, the advantages and disadvantages of the imaging probe were compared. In order to provide some reference and help researchers for construction imaging probe for tumour diagnosis and treatment, it attempts to exhaustively cover the whole field. Finally, the prospect and challenge for imaging probe were discussed.

VEMcomp: a Virtual Elements MATLAB package for bulk-surface PDEs in 2D and 3D

AbstractWe present a Virtual Element MATLAB solver for elliptic and parabolic, linear and semilinear Partial Differential Equations (PDEs) in two and three space dimensions, which is coined VEMcomp. Such PDEs are widely applicable to describing problems in material sciences, engineering, cellular and developmental biology, among many other applications. The library covers linear and nonlinear models posed on different simple and complex geometries, involving time-dependent bulk, surface, and bulk-surface PDEs. The solver employs the Virtual Element Method (VEM) of lowest polynomial order $${k=1}$$ k = 1 on general polygonal and polyhedral meshes, including the Finite Element Method (FEM) of order $${k=1}$$ k = 1 as a special case when the considered mesh is simplicial. VEMcomp has three main purposes. First, VEMcomp generates polygonal and polyhedral meshes optimized for fast matrix assembly. Triangular and tetrahedral meshes are encompassed as special cases. For surface PDEs, VEMcomp is compatible with the well-known Matlab package DistMesh for mesh generation. Second, given a mesh for the considered geometry, possibly generated with an external package, VEMcomp computes all the matrices (mass and stiffness) required by the VEM or FEM method. Third, for multiple classes of stationary and time-dependent bulk, surface and bulk-surface PDEs, VEMcomp solves the considered PDE problem with the VEM or FEM in space and IMEX Euler in time, through a user-friendly interface. As an optional post-processing, VEMcomp comes with its own functions for plotting the numerical solutions and evaluating the error when possible. An extensive set of examples illustrates the usage of the library.