Unconventional Materials Research Articles

Ultra‐Thin Strain‐Relieving Si1−xGex Layers Enabling III‐V Epitaxy on Si

AbstractThe explosion of artificial intelligence, the possible end of Moore's law, dawn of quantum computing, and the continued exponential growth of data communications traffic have brought new urgency to the need for laser integration on the diversified Si platform. While diode lasers on group III‐V platforms have long‐powered internet data communications and other optoelectronic technologies, direct integration with Si remains problematic. A paradigm‐shifting solution requires exploring new and unconventional materials and integration approaches. In this work, it is shown that a sub‐10‐nm ultra‐thin Si1−xGex buffer layer fabricated by an oxidative solid‐phase epitaxy process can facilitate extraordinarily efficient strain relaxation. The Si1−xGex layer is formed by ion implanting Ge into Si(111) and selectively oxidizing Si atoms in the resulting ion‐damaged layer, precipitating a fully strain‐relaxed Ge‐rich layer between the Si substrate and surface oxide. The efficient strain relaxation results from the high oxidation temperature, producing a periodic network of dislocations at the substrate interface, coinciding with modulations of the Ge content in the Si1−xGex layer and indicating the presence of defect‐mediated diffusion of Si through the layer. The epitaxial growth of high‐quality GaAs is demonstrated on this ultra‐thin Si1−xGex layer, demonstrating a promising new pathway for integrating III‐V lasers directly on the Si platform.

Preparation and evaluation pringles ( potato dough based snack product) from unconventional raw materials

Preparation and evaluation pringles ( potato dough based snack product) from unconventional raw materials

Adaptation Practices of Dairy Farmers to Climate Change in Coastal Tamil Nadu, India

An investigation was conducted to evaluate the adaptation strategies of dairy farmers in light of climate change in Tamil Nadu. For this research, four out of the 13 coastal districts—Villupuram, Cuddalore, Ramanathapuram, and Thoothukudi—were chosen at random. Two blocks were randomly picked from each district for analysis. From each selected block, two villages were randomly identified from the existing villages. Consequently, 16 villages were included in this study. Fifteen dairy farmers were randomly selected from each village, yielding a total of 240 respondents for the research. Data were gathered using a predesigned interview schedule. The information collected was analyzed with suitable statistical tools to interpret the results of this research. It can be concluded that the area studied was primarily populated by crossbred cattle due to their high productivity, and “no distinct alterations of forage in the diet” were observed by fewer than half (48.33%) of the dairy farmers during periods of heat or cold stress. A notable 62.92 percent of dairy farmers did not employ feed additives during these distressing times, opting instead for a feeding strategy that involved “crop residues + unconventional materials” in drought conditions. It emerged that they were compelled to source water from open areas as adequate drinking water was not consistently available during drought periods. The majority of dairy farmers (70.42%) opted for a combination of “consult veterinarian + ethno veterinary practices” for addressing reproductive issues amid extreme weather events.

Thermal insulation enhanced by the dopant-induced phonon softening discovered in thermoelectric Heusler compounds

Suppression of phonon transports is a key requirement to achieve high thermoelectric performance, which has been often realized by doping an element to enhance the phonon scattering. However, detailed origins behind the dopant-induced low lattice thermal conductivity (κph) have not yet been comprehensively understood. Here, we demonstrate a κph reduction mechanism induced by the phonon softening in the element-doped Fe2VAl thermoelectric Heusler compounds. Inelastic X-ray scattering experiments revealed that overall optical phonons are softened with increasing Ti-doping concentration in marked contrast to the Ta-doped Fe2VAl. By means of photoelectron spectroscopy, we found that the observed phonon softening is originating from the rigid-band shift of the electronic density of states and the consequent deviation of the pseudo-gap position from the Fermi level, which causes the energetic instability of the electronic system. This instability is accompanied by the reduction of the filled bonding states, giving rise to the phonon softening. This mechanism of κph reduction caused by the close correlation between electronic and phononic systems will shed new light on achieving low-κph and thereby developing unconventional high-performance thermoelectric materials.

Unconventional insulator-to-metal phase transition in Mn3Si2Te6

The nodal-line semiconductor Mn3Si2Te6 is generating enormous excitment due to the recent discovery of a field-driven insulator-to-metal transition and associated colossal magnetoresistance as well as evidence for a new type of quantum state involving chiral orbital currents. Strikingly, these qualities persist even in the absence of traditional Jahn-Teller distortions and double-exchange mechanisms, raising questions about exactly how and why magnetoresistance occurs along with conjecture as to the likely signatures of loop currents. Here, we measured the infrared response of Mn3Si2Te6 across the magnetic ordering and field-induced insulator-to-metal transitions in order to explore colossal magnetoresistance in the absence of Jahn-Teller and double-exchange interactions. Rather than a traditional metal with screened phonons, the field-driven insulator-to-metal transition leads to a weakly metallic state with localized carriers. Our spectral data are fit by a percolation model, providing evidence for electronic inhomogeneity and phase separation. Modeling also reveals a frequency-dependent threshold field for carriers contributing to colossal magnetoresistance which we discuss in terms of polaron formation, chiral orbital currents, and short-range spin fluctuations. These findings enhance the understanding of insulator-to-metal transitions in new settings and open the door to the design of unconventional colossal magnetoresistant materials.

A New Paradigm on Waste-to-Energy Applying Hydrovoltaic Energy Harvesting Technology to Face Masks.

The widespread use of single-use face masks during the recent epidemic has led to significant environmental challenges due to waste pollution. This study explores an innovative approach to address this issue by repurposing discarded face masks for hydrovoltaic energy harvesting. By coating the face masks with carbon black (CB) to enhance their hydrophilic properties, we developed mask-based hydrovoltaic power generators (MHPGs). These MHPGs were evaluated for their hydrovoltaic performance, revealing that different mask configurations and sizes affect their efficiency. The study found that MHPGs with smaller, more structured areas exhibited better energy output, with maximum open-circuit voltages (VOC) reaching up to 0.39 V and short-circuit currents (ISC) up to 65.6 μA. The integration of CB improved water absorption and transport, enhancing the hydrovoltaic performance. More specifically, MHPG-1 to MHPG-4, which represented different sizes and features, presented mean VOC values of 0.32, 0.17, 0.19 and 0.05 V, as well as mean ISC values of 16.57, 15.59, 47.43 and 3.02 μA, respectively. The findings highlight the feasibility of utilizing discarded masks in energy harvesting systems, offering both environmental benefits and a novel method for renewable energy generation. Therefore, this work provides a new paradigm for waste-to-energy (WTE) technologies and inspires further research into the use of unconventional waste materials for energy production.

Two-Dimensional Semiconductors for State-of-the-Art Complementary Field-Effect Transistors and Integrated Circuits.

As the trajectory of transistor scaling defined by Moore's law encounters challenges, the paradigm of ever-evolving integrated circuit technology shifts to explore unconventional materials and architectures to sustain progress. Two-dimensional (2D) semiconductors, characterized by their atomic-scale thickness and exceptional electronic properties, have emerged as a beacon of promise in this quest for the continued advancement of field-effect transistor (FET) technology. The energy-efficient complementary circuit integration necessitates strategic engineering of both n-channel and p-channel 2D FETs to achieve symmetrical high performance. This intricate process mandates the realization of demanding device characteristics, including low contact resistance, precisely controlled doping schemes, high mobility, and seamless incorporation of high- κ dielectrics. Furthermore, the uniform growth of wafer-scale 2D film is imperative to mitigate defect density, minimize device-to-device variation, and establish pristine interfaces within the integrated circuits. This review examines the latest breakthroughs with a focus on the preparation of 2D channel materials and device engineering in advanced FET structures. It also extensively summarizes critical aspects such as the scalability and compatibility of 2D FET devices with existing manufacturing technologies, elucidating the synergistic relationships crucial for realizing efficient and high-performance 2D FETs. These findings extend to potential integrated circuit applications in diverse functionalities.

Synergistic effect of oxygen vacancies and in-situ formed bismuth metal centers on BiVO4 as an enhanced bifunctional Li–O2 batteries electrocatalyst

Bismuth Vanadate (BiVO4) is a promising oxide-based photoanode for electrochemical applications, yet its practical use is constrained by poor charge transport properties, particularly under dark conditions. This study introduces a novel BiVO4 variant (Bi-BiVO4-10) that incorporates abundant oxygen vacancies and in-situ formed Bi metal, significantly enhancing its electrical conductivity and catalytic performance. Bi-BiVO4-10 demonstrates superior electrochemical performances compared to conventional BiVO4 (C-BiVO4), demonstrated by its most positive half-wave potential with the highest diffusion-limiting current in the oxygen reduction reaction (ORR) and earliest onset potential in the oxygen evolution reaction (OER). Notably, Bi-BiVO4-10 is explored for the first time as an electrocatalyst for lithium-oxygen (Li–O2) cells, showing reduced overcharge (610 mV) in the first cycle and extended cycle life (1050 h), outperforming carbon (320 h) and C-BiVO4 (450 h) references. The enhancement is attributed to the synergy of oxygen vacancies, Bi metal formation, increased surface area, and improved electrical conductivity, which collectively facilitate Li2O2 growth, enhance charge transport kinetics, and ensure stable cycling. Theoretical calculations reveal enhanced chemical interactions between intermediate molecules and the defect-rich surfaces of Bi-BiVO4-10, promoting efficient discharge and charge processes in Li–O2 batteries. This research highlights the potential of unconventional BiVO4-based materials as durable electrocatalysts and for broader electrochemical applications.

Narrowband clusteroluminescence with 100% quantum yield enabled by through-space conjugation of asymmetric conformation

Different from traditional organic luminescent materials based on covalent delocalization, clusteroluminescence from nonconjugated luminogens relies on noncovalent through-space conjugation of electrons. However, such spatial electron delocalization is usually weak, resulting in low luminescent efficiency and board emission peak due to multiple vibrational energy levels. Herein, several nonconjugated luminogens are constructed by employing biphenyl as the building unit to reveal the structure-property relationship and solve current challenges. The intramolecular through-space conjugation can be gradually strengthened by introducing building units and stabilized by rigid molecular skeleton and multiple intermolecular interactions. Surprisingly, narrowband clusteroluminescence with full width at half-maximum of 40 nm and 100% efficiency is successfully achieved via an asymmetric conformation, exhibiting comparable performance to the traditional conjugated luminogens. This work realizes highly efficient and narrowband clusteroluminescence from nonconjugated luminogens and highlights the essential role of structural conformation in manipulating the photophysical properties of unconventional luminescent materials.

Comparison of outlier detection approaches for compressive strength of cement-based mortars

EN 196-1 states that the compressive strength result of testing of standard mortar specimens corresponds to the average of the six individual measurements. If one of the six individual measurements varies more than ±10 % from the average, it must be excluded, and a new average is calculated with the five remaining values. This methodology might be interesting for quality control or characterization of cement; however, it may not be the best approach for research or scientific purposes. Applying EN 196-1 to non-standard cement-based mortars with multiple and even unconventional supplementary cementitious materials may induce even more variation in the result. Also, mixtures with higher mechanical strength generally present the highest absolute variation. The main goal of the present work is to compare different methodologies, such as Tails of Normal Distribution, Thompson-Tau, Box-plot, T-test, Dixon Criteria, and other methods provided by engineering standards, to evaluate the existence of discrepant values and the effect of their exclusion (or not) on compressive strength experimental values, namely for science purposes. A sample of compressive strength of 338 mortar specimens was used The main findings revealed that excluding data points as a result of applying 8 of the 13 methods under study did not affect the mechanical strength result by more than ±5 %. The method described in the Brazilian standard that guides preparation, control, receipt, and acceptance for Portland cement concrete, would invalidate almost 46 % of all mixtures produced and did not prove to be reliable. Simplified methods of excluding outliers in relative or absolute percentages of 6 % around the average value can be considered an interesting option for professionals involved in laboratory testing of building materials. Otherwise, the authors would recommend applying the either Dixon Criteria or T test of the ASTM E178 for scientific purposes.

Integrating the Stimuli‐Responsiveness of Microparticles via Matrix Embedding for Smart Soft Materials with Customized Switchable Properties

AbstractSmart soft materials are the focus of extensive research efforts due to their potential applications in various fields. Inspired by nature, embedding smart micro‐inclusions in a soft substrate provides a feasible strategy to integrate the smartness of individual microparticles for creating smart materials at the macroscale, broadening the capabilities and applications of smart soft materials. This strategy decouples the design of intelligence and substrate materials, leading to a broader design space for both the smartness and the mechanical properties of the composites. In this Perspective, recent advances in creating smart soft materials using smart microparticles are summarized. The methods developed to construct composites of microparticles in a soft matrix are first introduced, followed by detailed discussions on the material compositions, stimuli and responsiveness, and properties of individual microparticles and the composite systems. Various applications based on advanced functionalities and capabilities that are enabled by those smart soft materials are highlighted. This study also points out research directions to further advance unconventional smart soft materials following this bioinspired approach.

Alternative concrete aggregates - Review of physical and mechanical properties and successful applications

Concrete is one of the most widely used construction materials, yet its production is associated with significant environmental impacts. One approach to mitigate such impacts is to use alternative aggregates. However, the limited knowledge about the availability and benefits of these unconventional materials, as well as concerns about their quality and performance, have hindered their adoption. This paper aims to analyse the potential benefits and limitations of using alternative aggregates in concrete by reviewing examples from three primary sources: construction and demolition waste (CDW), end-of-life materials (i.e., tyre rubber, glass, and plastic), and forest and agricultural waste (i.e., rice husk, wood, and hemp). First, the main sources and treatment needs are analysed. Then, a comprehensive macro analysis is provided on the physical and mechanical properties of concrete materials, discussing the results in terms of the aggregate nature and substitution ranges. The collected experimental data are also compared with estimations based on different models from two published codes, suggesting that more specific design-oriented models need to be developed to relate concrete's physical and mechanical properties using different waste-type aggregate replacements. Selected data analyses are presented to help the readers obtain the optimum content for specific structural or non-structural applications. Examples of successful application of alternative aggregates in construction projects and products are also provided and discussed.

Low-cost saw/sinus-tooth-shaped circular microstrip patch antenna for in-space and satellite applications

Antennas operating in S and C bands are crucial in space satellite applications due to their high bandwidth, which facilitates the swift transmission of large data volumes from space vehicles to Earth. These bands are less affected by atmospheric disturbances and exhibit lower noise levels, ensuring uninterrupted and reliable communication between spacecraft and Earth centers. They are essential for satellite-based remote sensing, analyzing surface properties, transmitting high-resolution images, scientific data, and other information. Additionally, they are used for spacecraft control and navigation, enabling precise mission operations. This study emphasizes user-friendly production antennas with different geometries and distinct feeding techniques, demonstrating various design implementations using CST Microwave Studio software. Innovative manufacturing methods such as 3D printing PLA substrates and using copper tape for antenna elements were explored to optimize costs and production processes. Precise cutting of antenna radiation geometries was achieved using the Cricut machine. Experimental validation through reflection coefficient (S11) measurements with a handheld vector network analyzer confirmed the practical application of theoretical foundations. The study’s novelty lies in examining unconventional materials like PLA filament for antenna substrates, exploring fractalization theory for enhancing bandwidth, and discussing advancements in material science with flexible filaments like TPU. These contributions offer insights into user-friendly antenna production, innovative manufacturing techniques, and theoretical explorations in antenna design, enhancing the efficiency and effectiveness of space satellite communication systems.

Production, optimization, and characterization of biodiesel from almond seed oil using a bifunctional catalyst derived from waste animal bones and almond shell

The search for environmentally friendly alternatives to conventional fossil fuels has been intensified by the global shift toward sustainable energy sources. With over 95% of the fuel market dominated by petroleum-based products, concerns regarding their limited biodegradability and high eco-toxicity have been escalated. In response, there is a growing demand for biobased solutions that can mitigate pollution and reduce greenhouse gas emissions. In this study, the synthesis of biodiesel from waste almond seed oil (WCO) was focused on, utilizing an innovative bifunctional catalyst derived from waste animal bones and almond shells. The efficacy of the catalyst synthesized from these unconventional materials was confirmed through rigorous characterization techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy, and Brunauer, Emmett, and Teller (BET) analysis. The physicochemical properties of WCO and the resulting biodiesel were evaluated according to ASTM D6751 and EN 14214 standards. To optimize the catalytic process, Box Behnken Design (BBD) was employed to explore the effects of key parameters: reaction temperature (40-60°C), reaction time (60-90 minutes), catalyst loading (0.5-1.5 wt%), and methanol-to-oil ratio (6:1-18:1). Remarkably, under optimal conditions, an impressive biodiesel yield of 86.2% was achieved. Specifically, the optimal parameters were a Methanol:Oil Ratio of 6.026, Catalyst Loading of 1.49917 wt%, Reaction Time of 66.8179 minutes, and Temperature of 59.9806°C. The potential of utilizing waste materials for sustainable biodiesel production is underscored by our findings. The bifunctional catalyst developed in this study represents a cost-effective and environmentally friendly alternative to conventional catalysts, contributing to cleaner fuel production methods.

Best-in-class modeling: A novel strategy to discover constitutive models for soft matter systems

The ability to automatically discover interpretable mathematical models from data could forever change how we model soft matter systems. For convex discovery problems with a unique global minimum, model discovery is well-established. It uses a classical top-down approach that first calculates a dense parameter vector, and then sparsifies the vector by gradually removing terms. For non-convex discovery problems with multiple local minima, this strategy is infeasible since the initial parameter vector is generally non-unique. Here we propose a novel bottom-up approach that starts with a sparse single-term vector, and then densifies the vector by systematically adding terms. Along the way, we discover models of gradually increasing complexity, a strategy that we call best-in-class modeling. To identify and select successful candidate terms, we reverse-engineer a library of sixteen functional building blocks that integrate a century of knowledge in material modeling with recent trends in machine learning and artificial intelligence. Yet, instead of solving the NP hard discrete combinatorial problem with 216=65,536 possible combinations of terms, best-in-class modeling starts with the best one-term model and iteratively repeats adding terms, until the objective function meets a user-defined convergence criterion. Strikingly, for most practical purposes, we achieve good convergence with only one or two terms. We illustrate the best-in-class one- and two-term models for a variety of soft matter systems including rubber, brain, artificial meat, skin, and arteries. Our discovered models display distinct and unexpected features for each family of materials, and suggest that best-in-class modeling is an efficient, robust, and easy-to-use strategy to discover the mechanical signatures of traditional and unconventional soft materials. We anticipate that our technology will generalize naturally to other classes of natural and man made soft matter with applications in artificial organs, stretchable electronics, soft robotics, and artificial meat.

Terahertz and Infrared Plasmon Polaritons in PtTe2 Type-II Dirac Topological Semimetal.

Surface plasmon polaritons (SPPs) are electromagnetic excitations existing at the interface between a metal and a dielectric. SPPs provide a promising path in nanophotonic devicesforlight manipulation at the micro and nanoscale with applications in optoelectronics, biomedicine, and energy harvesting. Recently, SPPs are extended to unconventional materials like graphene, transparent oxides, superconductors, and topological systems characterized by linearly dispersive electronic bands. In this respect, 3D Dirac and Weyl semimetals offer a promising frontier for infrared (IR) and terahertz (THz) radiation tuning by topologically-protected SPPs.In this work, the THz-IR optical response of platinum ditelluride (PtTe2) type-II Dirac topological semimetal films grown on Si substrates is investigated. SPPs generated on microscale ribbon arrays of PtTe2are detected in the far-field limit,finding an excellent agreement among measurements, theoretical models, and electromagnetic simulation data.The far-field measurements are further supported by near-field IR data which indicate a strong electric field enhancement due to the SPP excitation near the ribbon edges. The present findings indicate that the PtTe2ribbon array appears an idealactive layout for geometrically tunable SPPs thus inspiring a new fashion of optically tunable materials in the technologically demanding THz and IR spectrum.

Multi-method examination of contact mechanics in orthotropic layers under gravity

Analyzing the behavior of intelligent unconventional materials under diverse contact scenarios, in comparison to conventional materials, is a critical step in the initial design of engineering systems. This paper presents the development of analytical and numerical approaches for analyzing contact mechanics in a system comprising an orthotropic layer resting on a rigid foundation. Parametric analyses include the consideration of cylindrical and flat punch profiles. Analytical formulation utilizes integral transform methods to convert planar elasticity equations into a Cauchy-type singular integral equation of the second kind. A detailed description of the solution technique for the integral equation is provided, encompassing both the analytical formulation and the required discretization for obtaining the solution. Subsequently, a finite element approach (FEA) is employed to approximate contact bodies using a collection of finite elements, while contact boundaries are approximated by utilizing a set of polygons. Alternatively, the problem is addressed using the Multilayer Perceptron approach, a form of artificial neural network frequently applied in diverse machine learning applications, including scenarios involving contact problems. Finally, the resolution to the problem is achieved by employing the multilayer perceptron (MLP) method. The study yields determinations of contact stresses under the punch, the critical separation load resulting in the detachment of the orthotropic layer from the rigid foundation, and the corresponding separation distance. This analysis considers a range of dimensionless parameters and explored the behavior of diverse orthotropic materials. Comparisons between the results of the analytical method and computations from FEA and MLP reveal the exceptional accuracy attained by all three approaches. As the pioneer study employing three distinct approaches to examine continuous contact mechanics within an orthotropic layer under the influence of gravity, this research constitutes a valuable point of reference for upcoming scholars in the field.

Pleurotus ostreatus Mushroom: A Promising Feed Supplement in Poultry Farming

Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm mushrooms are cultivated on diverse by-products based on substrates that hold promise for mitigating antibiotic usage in the poultry industry and reducing environmental pollution. By incorporating agricultural by-products into mushroom cultivation, the functionality of the mushroom products can be increased, then the final product can be a more effective feed supplement. After mushroom cultivation, spent mushroom substrate (SMS) can be valorized, due to the presence of huge amounts of bioactive compounds like β-glucan, chitin, polyphenols, and flavonoids related to mycelia. As a prebiotic and antimicrobial feed supplement, these mushrooms positively influence gut microbiota, intestinal morphology, and thus overall poultry well-being. This article underscores the potential of solid-state fermentation (SSF) to enhance the bioactivity of oyster mushrooms and their derivatives, offering a cost-effective and efficient strategy for transforming unconventional feeding materials. Moreover, it emphasizes broader implications, including the reduction of antibiotic dependence in poultry farming, highlighting the promising integration of oyster mushrooms and their derivatives for sustainable and environmentally conscious poultry production.

Activated date carbon: a sustainable solution for Pentachlorophenol adsorption in reused wastewater

Industrial wastewaters contain persistent and toxic organic compounds that pose a significant risk to public health and the environment upon release. Phenol and its derivatives are examples of such pollutants. Activated carbon, often sourced from unconventional materials like plant biomass, provides a sustainable solution for treating wastewater. This research focuses on creating activated carbon from date nuts through chemical activation with phosphoric acid. The effectiveness of this carbon in removing pentachlorophenol (PCP) from secondary wastewater (SWW) is evaluated. The analysis of the date nut activated carbon (DAC) includes studying its adsorption capacities for iodine and Methylene Blue, surface functional groups, and the point of zero charge (pHpzc) compared to a commercial activated carbon (CAC). The DAC demonstrates promising adsorption capacities, with values of 368.03 mg/g for iodine and 619.9 mg/g for Methylene Blue, which are close to those of the CAC (444.17 mg/g and 620.25 mg/g, respectively). Both DAC and CAC exhibit acidic surface functionalities, with pHpzc values below 10. The efficiency of PCP removal from SWW contaminated with PCP (100 mg/L) reaches 78% within 72 hours. This study indicates that using DAC for PCP removal from SWW is a sustainable approach for wastewater treatment, potentially allowing for the reuse of non-traditional water sources.

Tools and Machines for Carving in Wood

In this article, the properties and working methods of the tools and machines for wood carving are analyzed, starting with the simplest and primitive tools for processing materials up to the most complex machines. Wood is one of the oldest materials practiced in sculpture, and the following traditional tools are used for its processing: chisels, hammers, saws, abrasives. Along with the development of the industrial era, tools and machines for processing materials also developed. Therefore, it is found that the use of both traditional and modern utensils provides an opportunity to bring out the shape, texture, color and beauty of the sculpture. The working tools chosen by the artist, whether simple or complex, depend on the material used to make the work. This dependence has contributed to the development and modernisation tools and machinery for processing the materials used in sculpture, with the discovery and increasing knowledge of the ideational value offered by the material, be it clay, wood, stone, metal or unconventional materials.