Green Matrix Research Articles

Fe3O4@SiO2 core/shell functionalized by gallic acid: a novel, robust, and water-compatible heterogeneous magnetic nanocatalyst for environmentally friendly synthesis of acridine-1,8-diones.

In this study, we conveniently prepared a novel robust heterogeneous magnetic nanocatalyst using a Fe3O4@SiO2 core/shell stabilized by gallic acid. The catalyst was completely characterized by various physicochemical techniques, including infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), potentiometric titration, energy dispersive X-ray microanalysis (EDX), vibrating sample magnetometer (VSM), zeta potential analysis, and BET. The potential ability of the newly developed sulfonated nanocatalyst was then exploited in the multicomponent synthesis of acridine-1,8-dione derivatives by considering the green chemistry matrix and under mild conditions. Various aldehydes and amines were smoothly reacted with dimedone, affording the desired products in good to excellent yields. The introduction of sulfonic groups using gallic acid allowed the development of a water-compatible and highly recyclable catalytic system for reactions in an aqueous environment. The prepared catalyst can be readily magnetically separated and reused eight times without significant loss of activity. High synthetic efficiency, using a recyclable and eco-sustainable catalyst under mild conditions, and easy product isolation are salient features of this catalytic system, which makes this protocol compatible with the demands of green chemistry.

Assessing sustainability and green chemistry in synthesis of a Vanillin-based vitrimer at scale: Enabling sustainable manufacturing of recyclable carbon fiber composites

Sustainable manufacturing of carbon fibre (CFs) reinforced polymer (CFRP) composites featured technically by low-cost and rapid manufacturing techniques, use of renewable materials, and non-destructive recycling process. By developing an inherently recyclable thermoset, this research bridges between these three components of sustainable manufacturing by focusing on a fast cured vanillin-based Schiff base polyimide network in all-solid state. In this study, a multifunctional vanillin-based monomer was synthesised at scale in water which can be cured using a diamine without requiring any organic solvent. A CFRP was fabricated using this newly developed Schiff base polymer using compression moulding technique, and its mechanical and thermal/fire performance were compared to a CFRP made of a commercially available automotive grade epoxy resin. The resulting Schiff base CFRP composite demonstrated exceptional fire retardancy, complemented by remarkable tensile strength and modulus values of 427 MPa and 45 GPa, respectively. These characteristics meet the criteria for a broad spectrum of high-performance applications. In contrast to conventional CF reclaiming processes, a novel and efficient chemical recycling approach was introduced, enabling the delamination of CF layers containing the Schiff base network without requiring the separation and purification of the polymer matrix. This approach facilitates the low-cost remanufacturing of new CFRP composites with mechanical performance comparable to the original composite. Finally, green chemistry matrices as well as simplified life cycle assessment (LCA)-like approaches, including the EcoScale and GREEN MOTION rates, were employed to evaluate the efficiency and environmental impact of the CFRP manufacturing process.

Параболічні крайові задачі математичної фізики в кусково-однорідному клиновидному циліндрично-круговому півпросторі з порожниною

The unique exact analytical solutions of parabolic boundary value problems of mathematical physics in piecewise homogeneous by the radial variable r wedge-shaped by the angular variable φ cylindrical-circular half-space with a cavity were constructed at first time by the method of classical integral and hybrid integral transforms in combination with the method of main solutions (matrices of influence and Green matrices) in the proposed article. The cases of assigning on the verge of the wedge the boundary conditions of the 1st kind (Dirichlet) and the 2nd kind (Neumann) and their possible combinations (Dirichlet – Neumann, Neumann – Dirichlet) are considered. Finite integral Fourier transform by an angular variable, a finite integral Fourier transform on the Cartesian semiaxis (0; +∞) by an applicative variable z and a Weber hybrid integral transform type on the polar axis (R0; +∞) with n points of conjugation by a radial variable were used to construct solutions of investigated boundary value problems. The consistent application of integral transforms by geometric variables allows us to reduce the three-dimensional initial boundary-value problems of conjugation to the Cauchy problem for a regular linear inhomogeneous 1st order differential equation whose unique solution is written in a closed form. The consistent application of inverse integral transforms to the obtained solution in the space of images restores the solutions of the considered parabolic boundary value problems through their integral image in an explicit form in the space of the originals. At the same time, the main solutions to the problems were obtained in an explicit form.

Application of data science in the prediction of solar energy for the Amazon basin: a study case

Abstract The need for renewable energy sources has challenged most countries to comply with environmental protection actions and to handle climate change. Solar energy figures as a natural option, despite its intermittence. Brazil has a green energy matrix with significant expansion of solar form in recent years. To preserve the Amazon basin, the use of solar energy can help communities and cities improve their living standards without new hydroelectric units or even to burn biomass, avoiding harsh environmental consequences. The novelty of this work is using data science with machine-learning tools to predict the solar incidence (W.h/m²) in four cities in Amazonas state (north-west Brazil), using data from NASA satellites within the period of 2013–22. Decision-tree-based models and vector autoregressive (time-series) models were used with three time aggregations: day, week and month. The predictor model can aid in the economic assessment of solar energy in the Amazon basin and the use of satellite data was encouraged by the lack of data from ground stations. The mean absolute error was selected as the output indicator, with the lowest values obtained close to 0.20, from the adaptive boosting and light gradient boosting algorithms, in the same order of magnitude of similar references.

Thermal, mechanical, thermo‐mechanical and morphological properties of graphene nanoplatelets reinforced green epoxy nanocomposites

AbstractThe efficient inclusion of GNPs (graphene nanoplatelets) as an effective nano‐fillers for green polymer matrices produced with 28% of carbon originating from biomass tends to significantly improve mechanical and thermal properties. In the present work, green epoxy nanocomposites with low loading of (0.1, 0.25, and 0.5) wt% of the GNPs were made using a solution blending technique using acetone as the solvent. In mechanical stirring, the ultrasonic bath was used to ensure the efficient dispersion of GNPs within green epoxy. The resulting nanocomposites were comprehensively characterized and compared to unfilled green epoxy. Different tools were used to appraise morphological, thermal, thermo‐mechanical, and mechanical behavior. The results confirmed through FE‐SEM showed an optimal dispersion of GNPs with nanocomposites. The thermal degradation temperature (Td) of GNPs curve with 0.25 wt% loading was shifted toward higher temperature (from 336°C to 342°C) due to low percentage of loading of GNPs which showed an enhance thermal stability of polymer matrix with 0.25 wt% loading. The mechanical results were also in lined with previously published literature, in the tensile test 6.45% and hardness 13.3% increment was achieved. Overall, the results underscored significant improvements in green nanocomposite performance with low wt% of GNPs.Highlights The study focuses on development and characterization of green epoxy nanocomposites, which utilize environmentally friendly materials as a matrix, highlighting the significance of sustainability. The study explores effects of low loading of GNPs in green epoxy nanocomposites. The results demonstrate significant improvements in mechanical and thermal properties with optimized presence of GNPs. This investigation provides insights into optimal amount of GNPs required to achieve improved properties. Research evaluates multifaceted analysis provides a holistic understanding of performance enhancements achieved through inclusion of GNPs.

Ecological soap production using green chemistry principles

The reuse of fatty materials for soap production is considered a viable alternative to minimize environmental problems such as the eutrophication of lakes and rivers and to reduce the high costs of effluent treatment and domestic water supply. This research presents protocols for ecological soap production from the determination of the saponification index (SI) using the principles of Green Chemistry. The chemical greenness of the produced soap was assessed using mass and holistic metrics. The SI measurement ensured a final product without residues, aligning with the principles of Green Chemistry: principle 1 (waste prevention) with a Factor E of 0 and an Atomic Economy of 100%. Additionally, the Green Matrix and Green Star analyses demonstrated a more sustainable experimental approach for bar soap production, with 45% higher greenness compared to traditional soap and 95% greenness for ash soap. The changes in the saponification process by the principles of green chemistry allowed ecological soap production without residues, an innocuous product to health and the environment. The methodology proposed in this research can contribute to minimizing an environmental problem related to the incorrect disposal of non-biodegradable oil.

Corrosion analysis of unearthed jade from Daye Zhen Tomb of Northern Zhou Dynasty

X-ray fluorescence spectroscopy, scanning electron microscopy energy spectrum, excitation-emission matrix spectroscopy, and Fourier transform infrared spectroscopy was applied to the unearthed jade with multilayered corrosion, to reveal the microstructure, composition structure, and distribution of organic matters. Our results showed that the interior of the jade was mainly composed of layered serpentine with a regular structure, while the white layer structure on the surface is scattered and irregular, and the content of calcite formed by elements Ca and C increases significantly; between the green matrix and the white layer on the surface, there are brown corrosion zones with obvious fluorescence effect and mainly composed of humic acid, which continuously extends inward along the corrosion cracks for accelerating the internal corrosion. This article, for the first time, argued for the corrosive and fluorescent humic acid bands that appear inside serpentine jade and cautions its role in investigating the corrosion of jade.

Mechanochemical Nickel-Catalyzed Carbon-Sulfur Bond Formation between Aryl Iodides and Aromatic Sulfur Surrogates.

The formation of aromatic thioethers from C-S coupling is of great importance in synthetic chemistry. Traditional solution strategies through transition-metal catalysis generally require bulk solution, heat, and longer reaction time. Herein, a mechano-promoted sulfenylation of aryl iodides with nickel catalysis is described. The active aromatic sulfide agents are in-situ generated from aromatic thiol or disulfide and subsequently adapted in the nickel catalytic cycle, with a tolerance of broad substituted groups under optimized conditions. In addition to the gram-scale synthesis that reveals the application potential of the method, the radical trapping and competitive experiments are also conducted for the mechanistic study, thus providing a plausible mechanism rationally. Furthermore, the proposed methodology is certificated as being versatile and following the green principles with ideal calculated values of green chemistry metrics, and the comparison with other approaches for C-S bond formation is also demonstrated.

Development of a Green Competency Matrix Based on Civil Servants’ Perception of Sustainable Development Expertise

This paper analysed the responses of 242 civil servants collected during a survey for public authorities personnel with management or executive responsibilities. The survey focused on the perception of respondents regarding the key competencies and the utility of the sustainability development expert occupation (SDE). Based on the assumption that the responses were influenced by multiple factors, the impact of perceptual theory, agency theory and sustainability theory calibrated the analysis of the collected data. Cronbach’s alpha was used to test the reliability of the received responses and multinominal logistic regression with a single dichotomous variable (Regulation Awareness) and several continuous predictor variables (Specialization, Knowledge, Attributions and Competence) was employed to determine to what extent the SDE occupation would contribute to the implementation of sustainable development policies. This paper argues that the ‘green’ competency matrix appropriate for the implementation of sustainable development policies should include executive, compliance promoting, ethical and reporting competencies. The creation of a green competency matrix is an important step toward changing the organisational culture of the public or private sectors to achieve sustainable and reliable development. This research can help organizations and public authorities understand where their efforts should be focused to efficiently incorporate sustainability development into their systems.

Decay estimates of Green's matrices for discrete-time linear periodic systems

We study periodic Lyapunov matrix equations for a general discrete-time linear periodic system B p x p − A p x p − 1 = f p , where the matrix coefficients B p and A p can be singular. The block coefficients of the inverse operator of the system are referred to as the Green matrices. We derive new decay estimates of the Green matrices in terms of the spectral norms of special solutions to the periodic Lyapunov matrix equations. The study is based on the periodic Schur decomposition of matrices.

Study of Ultrasonic Guided Wave Propagation in Bone Composite Structures for Revealing Osteoporosis Diagnostic Indicators.

Tubular bones are layered waveguide structures composed of soft tissue, cortical and porous bone tissue, and bone marrow. Ultrasound diagnostics of such biocomposites are based on the guided wave excitation and registration by piezoelectric transducers applied to the waveguide surface. Meanwhile, the upper sublayers shield the diseased interior, creating difficulties in extracting information about its weakening from the surface signals. To overcome these difficulties, we exploit the advantages of the Green's matrix-based approach and adopt the methods and algorithms developed for the guided wave structural health monitoring of industrial composites. Based on the computer models implementing this approach and experimental measurements performed on bone phantoms, we analyze the feasibility of using different wave characteristics to detect hidden diagnostic signs of developing osteoporosis. It is shown that, despite the poor excitability of the most useful modes associated with the diseased inner layers, the use of the improved matrix pencil method combined with objective functions based on the Green's matrix allows for effective monitoring of changes in the elastic moduli of the deeper sublayers. We also note the sensitivity and monotonic dependence of the resonance response frequencies on the degradation of elastic properties, making them a promising indicator for osteoporosis diagnostics.

Green Matrices, Minors and Hadamard Products

Green matrices are interpreted as discrete version of Green functions and are used when working with inhomogeneous linear system of differential equations. This paper discusses accurate algebraic computations using a recent procedure to achieve an important factorization of these matrices with high relative accuracy and using alternative accurate methods. An algorithm to compute any minor of a Green matrix with high relative accuracy is also presented. The bidiagonal decomposition of the Hadamard product of Green matrices is obtained. Illustrative numerical examples are included.

Accurate and fast computations with Green matrices

This paper provides a linear time complexity method to obtain the bidiagonal decomposition of Green matrices with high relative accuracy. In addition, when the Green matrix is nonsingular and totally positive, this bidiagonal decomposition can be used to compute the eigenvalues, the inverse and the solution of some linear system of equations with high relative accuracy. A numerical example illustrates the advantages of this method.

Assessment of eggshell and CaCO3 reinforced recycled aluminium green metal matrix

In this study, an environmentally friendly metal matrix was prepared, and the influence of eggshell powder and CaCO3 particles on the tensile strength and hardness of recycled aluminium were assessed.A matrix made of recycled aluminium was employed. Calcium carbonate and eggshells served as the study's reinforcing materials. Separately, weight percentages of 2, 4, and 8% of eggshell and calcium carbonate were used. The samples were made by sand-casting.The results showed that both eggshell and calcium carbonate positively affect the hardness, yield, and ultimate tensile strength of recycled aluminium. The hardness values were improved as the percentage of the eggshell increased. The maximum hardness was achieved at 2% calcium carbonate. Similarly, the highest improvement of yield strength was for 2% CaCO3 addition, while the highest tensile strength was obtained at 8% eggshell addition.To get better results, it would be desirable to use finer eggshells than those utilized in this study.Composites made with an aluminium matrix exhibit exceptional mechanical and physical characteristics. The most challenging obstacle to overcome is the cost of metal matrix composites. Eggshells are a by-product that could be employed as a lightweight, affordable form of reinforcement. One way to get rid of this by-product, improve composite characteristics, and lower the cost of aluminium composite is to use eggshells.A comparative investigation was carried out to determine the effects of adding agricultural by-product eggshell, and commercial CaCO3 reinforcement material on the characteristics of recycled aluminium matrix integrated 425 m sized eggshell and CaCO3 separately as a reinforcement material to create a metal matrix that is beneficial to the environment.

Report on Current Trends and Future Research Challenges in Green Cloud Computing

Abstract: Cloud computing provides computing power and resources as a service to users across the globe. This scheme was introduced as a means to an end for customer’s worldwide, providing high performance at a cheaper cost when compared to dedicated high-performance computing machines. This provision requires huge data-centers to be tightly-coupled with the system, the increasing use of which yields heavy consumption of energy and huge emission of CO2. Since energy has been a prime concern of late, this issue generated the importance of green cloud computing that provides techniques and algorithms to reduce energy wastage by incorporating its reuse. In this survey we discuss key techniques to reduce the energy consumption and CO2 emission that can cause severe health issues. We begin with a discussion on green matrices appropriate for data-centers and then throw light on green scheduling algorithms that facilitate reduction in energy consumption and CO2 emission levels in the existing systems. At the same time the various existing architectures related to green cloud also discussed in this paper with their pros and cons.

A Study on Green Cloud Computing

Abstract: Cloud computing provides computing power and resources as a service to users across the globe. This scheme was introduced as a means to an end for customer’s worldwide, providing high performance at a cheaper cost when compared to dedicated high-performance computing machines. This provision requires huge data-centers to be tightly-coupled with the system, the increasing use of which yields heavy consumption of energy and huge emission of CO2. Since energy has been a prime concern of late, this issue generated the importance of green cloud computing that provides techniques and algorithms to reduce energy wastage by incorporating its reuse. In this survey we discuss key techniques to reduce the energy consumption and CO2 emission that can cause severe health issues. We begin with a discussion on green matrices appropriate for data-centers and then throw light on green scheduling algorithms that facilitate reduction in energy consumption and CO2 emission levels in the existing systems. At the same time the various existing architectures related to green cloud also discussed in this paper with their pros and cons.

Electromagnetic radiation in chiral matter: The Cherenkov case

Starting from the modified Maxwell equations in Carroll-Field-Jackiw electrodynamics we study the electromagnetic radiation in a chiral medium characterized by an axion coupling $\theta(x)=b_\mu x^\mu$, with $b_\mu= (0,\mathbf{b})$, which gives rise to the magnetoelectric effect. Employing the stationary phase approximation we construct the Green's matrix in the radiation zone which allows the calculation of the corresponding electromagnetic potentials and fields for arbitrary sources. We obtain a general expression for the angular distribution of the radiated energy per unit frequency. As an application we consider a charge moving at constant velocity parallel to $\mathbf{b}$ in the medium and discuss the resulting Cherenkov radiation. We recover the vacuum Cherenkov radiation. For the case of a material with refraction index $n > 1$ we find that zero, one or two Cherenkov cones can appear. The spectral distribution of the radiation together with the comparison of the radiation output of each cone are presented, as well as some angular plots showing the appearance of the cones.

Unraveling the Green Growth Matrix: Exploring the Impact of Green Technology, Climate Change Adaptation, and Macroeconomic Factors on Sustainable Development

The primary objective of this paper is to investigate the extent to which climate change adaptation and green technology diffusion serve as key drivers for green growth. Additionally, the study examines the influence of various economic, environmental, and social factors on green growth. Utilizing an annual panel dataset comprising 38 OECD member countries from 1990 to 2020, a series of dynamic panel data models are estimated using the system generalized method of moments (GMM) approach. The empirical results provide novel and robust evidence that the diffusion of green technology and climate change adaptation exert a significant positive influence on green growth. Furthermore, the findings highlight the significant role played by macroeconomic, institutional, social, and government policy-related factors in promoting green growth. These insights have substantial policy implications for the development and implementation of strategies that encourage climate change adaptation and green innovation. As a result, policymakers should prioritize the integration of green technology and climate change adaptation measures in their sustainable development agendas to foster a greener, more resilient future.

Sharjah Sustainable City: An Analytic Hierarchy Process Approach to Urban Planning Priorities

In 2020, the Sharjah Investment and Development Authority (SHUROOQ) initiated the Sharjah Sustainable City (SSC) project, with an investment of 2 billion AED (approximately 545 million USD) covering an area of 668,900 km2. This pioneering residential community in the United Arab Emirates (UAE) provides its residents with access to renewable energy storage solutions while adhering to the highest standards of green economy and environmental sustainability. This paper aims to examine the urban planning components of SSC and establish suitable priorities for these elements. To achieve this, we first reviewed and extracted sustainable urban planning elements from existing research. These elements were then organized hierarchically for an expert survey, which was conducted via email. The results were subsequently analyzed using the analytic hierarchy process (AHP). Our findings revealed that the transportation system sector was deemed most important, with a score of 0.283, followed by the energy/building sectors at 0.263. Conversely, the park/green area held relatively lower importance, with a score of 0.092. Upon examining the relative importance of 15 specific planning elements (lower criteria), energy-efficient building design emerged as the most critical aspect (0.121). Other highly valued elements included public transportation-oriented development (0.115) and the use of renewable energy (0.102). In contrast, building greening (0.029), establishment of accessible greenway and green matrix in residential areas (0.029), and creation of hydrophilic features for the water circulation system (0.026) were perceived as less significant. This study is expected to serve as foundational data for the future implementation of the SSC master plan in Sharjah. Moreover, it offers valuable insights and a methodology for sustainable urban planning that can be adopted or adapted globally. The worldwide applicability of this research fosters knowledge transfer, international cooperation, and innovation, thereby promoting sustainable development, urban resilience, and progress towards the United Nations’ Sustainable Development Goals (SDGs), specifically, SDG 11 (Sustainable Cities and Communities) and SDG 13 (Climate Action).

Characterization of the Thermoset Blend of a Vinyl Ester Resin with Eco-friendly Epoxidized Corn Oil as a Potential Sustainable Composite Matrix Resin

In this work, we investigated the influence of a novel green flame-retardant thermoset complex matrix resin, VEECO, produced by thermoset blending of epoxidized corn oil (ECO) with a vinyl ester (VE) resin. The new polymer blend was made with the ECO content at an optimal amount of 15%. After characterization, it was discovered that the VEECO15 blend cured at 8 h had its glass transition improved by 6.38%. Regarding its mechanical properties, the improvements were as follows: flexural strength, 19.36%; modulus, 123.53%; and impact energy, 29.08%. The flammability property for the heat release rate was improved by 20.62% and, most importantly, emissions of CO and CO2 were reduced by 62.73 and 49.34%, respectively, demonstrating its potential for sustainability. As a result of the proposed synthesis mechanism, the hydrogen bonding suggests the introduction of ECO as a biobased polymeric material. Overall, the polymer blend offers a new source of hybrid eco-thermoset resin that could mitigate the increasing consumption and environmental impact of BPA-based thermoset polymers. This material is expected to be a potential source of sustainable composites for a rapidly growing carbon-free society and eco-friendly urban development.