Search Results (61)

Technical change plays a crucial role in improving environmental quality, while the influence of demand-side factors remains insufficiently examined. To clarify the pull effect of consumer demand on the transition to clean technology, this study develops a model of directed technical change incorporating quality innovation in consumer goods. The analysis shows that the relative prices and market sizes of clean consumer goods drive the transition to clean technology, generating a direct demand-induced pull for clean innovations. Income inequality determines the market size of clean relative to dirty goods, thereby shaping innovation incentives and influencing the effectiveness of environmental policies. By integrating learning-by-doing and demand-induced innovation for dirty and clean technologies, respectively, the model captures the path dependence of technological progress and explains the dynamic ‘U-shaped’ evolution of environmental quality under environmental policy intervention. These findings provide theoretical insight into how consumer heterogeneity and income distribution affect the direction of innovation and the long-term transition toward cleaner technologies. Full article

To advance “bamboo-as-plastic-substitute” initiatives and the sustainable use of furniture materials, this study investigates flattened bamboo sheets by determining their principal-direction elastic constants and evaluating two common furniture T-joints—dowel-jointed panel-type and right-angle mortise-and-tenon frame-type—through tensile and bending load-bearing tests alongside finite element (FE) comparisons. The results show a pronounced anisotropy, with the longitudinal elastic modulus markedly higher than in other directions. At the joint level, the average ultimate load-bearing capacities were 4.06 kN (panel-type tension), 3.70 kN (frame-type tension), 0.264 kN (panel-type bending), and 0.589 kN (frame-type bending). Under identical structural configurations and boundary conditions, the tensile and bending capacities of flattened bamboo sheets were comparable to or exceeded those of the comparator materials (MDF, cherry wood, bamboo-based composites), and failures predominantly occurred in the adhesive layer rather than the bamboo substrate. Across four representative cases, FE predictions achieved a mean absolute percentage error (MAPE) of 6.5% with a maximum relative error of 12.5%; the regression correlation was R² ≈ 0.999 based on four paired observations, which should be interpreted with caution due to the small sample size. The study validates that FE models driven by experimentally measured anisotropic parameters can effectively reproduce the mechanical response of flattened bamboo T-joints, providing a basis for structural design, lightweighting, and parameter optimization in furniture applications. Further work should characterize adhesive systems, environmental durability, and interfacial failure mechanisms to enhance the model’s general applicability. Full article

The influence of vanadium substitution on the structure, elastic, mechanical, and magnetic behavior of lithium ferrite (Li_0.5+xV_xFe_2.5−2xO₄; x = 0.00–0.2) was systematically studied. X-ray diffraction (XRD) was used to investigate the crystal structure, and infrared spectroscopy (IR) was used to determine the cation distribution between the two ferrite sublattices, in addition to the elastic and mechanical behavior of Li_0.5+xV_xFe_2.5−2xO₄ ferrites. X-ray analysis revealed a monotonic decrease in lattice parameter from 8.344 Å to 8.320 Å with increasing V⁵⁺ content, confirming lattice contraction and stronger metal–oxygen bonding. Despite a moderate increase in porosity (from 6.9% to 8.9%), the elastic constants C₁₁ and C₁₂ increased, indicating improved stiffness and reduced compressibility. The derived Young’s, bulk, and rigidity moduli rose with the doping of V⁵⁺. Correspondingly, the longitudinal, shear, and mean velocities (V_l, V_s, and V_m) increased. The Debye temperature also showed a linear rise from 705 K to 723 K with V⁵⁺ doping, directly reflecting enhanced lattice stiffness and phonon frequency. Furthermore, both the saturation magnetization (M_S) and the initial permeability (μ_i) increased up to V⁵⁺ concentration x = 0.1 and then decreased. Curie temperature (T_C) decreased with increasing V⁵⁺ concentration, while both the saturation magnetization (M_S) and the initial permeability (μ_i) increased up to V⁵⁺ concentration x = 0.1 and then decreased, while the coercivity (H_C) showed the reverse trend. These results confirm that V⁵⁺ incorporation significantly enhances the Li ferrite, improving its elastic strength, lattice energy, thermal stability, and magnetically controlling properties and making them suitable for a variety of daily uses such as magneto-elastic sensors, high-frequency devices, and applications requiring mechanically robust ferrite materials. Full article

Motivated by the Generation-Skipping Transfer Tax (GSTT) in the United States, we examine how varying estate tax rates by the heir’s age affects welfare. Methodologically, we introduce a parsimonious constant elasticity of substitution (CES) bequest utility that is markedly more tractable than the altruistic specifications commonly used in the literature, delivering closed-form optimal rules and transparent parameterization. Using this new framework, we provide a proof of concept showing how transfers from older to younger generations can enhance equilibrium welfare in a dynamically efficient economy à la Samuelson (1975). We embed the tractable bequest utility in a two-period overlapping-generations model with age-dependent estate tax schedules. Numerical exercises—parameterized to the fact that estate tax revenue is small relative to labor income taxation—indicate that lowering the tax rate on bequests to younger heirs (grandchildren) relative to older heirs (adult children) raises the present value of lifetime resources and overall welfare, effectively reversing the logic of the current GSTT. The findings highlight a practical avenue for implementing a “reverse social security” transfer from old to young that can improve welfare in dynamically efficient economies. Full article

Nearshoring in Mexico is expanding rapidly, yet chronic volatility in the national power grid threatens the reliability and cost-competitiveness of relocated manufacturing lines. To inform strategic mitigation, this study presents a hybrid Fuzzy–CES decision-support framework that embeds the Constant-Elasticity-of-Substitution (CES) production function within a Mamdani Fuzzy-Inference Engine, implemented in both Type-1 and Interval Type-2 variants, to evaluate and optimize production adaptability in energy-constrained environments. Using sector-wide data from Mexico’s automotive industry, key input variables (energy reliability, capital intensity, and labor availability) are objectively quantified and normalized to reflect the realities of regional plant operations. The system linguistically classifies each facility’s production elasticity as low, moderate, or high, and generates actionable recommendations for resource allocation, such as targeted investments in renewable microgrids or workforce strategies. Implemented in MATLAB, simulation results confirm that, while high capital and labor inputs are essential, energy reliability remains the primary bottleneck limiting adaptability; only states with all three strong factors achieve maximum resilience. The Type-2 fuzzy approach demonstrates superior robustness to input uncertainty, enhancing managerial decision-making under volatile grid conditions. In addition, a case study regarding the automotive industry is presented to illustrate how the proposed framework is implemented. The same structure can be used to deploy it in another industry. This research offers a transparent, data-driven tool to inform both firm-level investment and regional policy, directly supporting Mexico’s efforts to sustain competitiveness and resilience in the global shift toward nearshoring. Full article

Polysuccinimide (PSI) is a biodegradable, extended-release polymer with great potential for developing active food packaging. In this study, we prepared PSI films functionalized with oregano essential oil (OEO, 3.5% w/w) and reinforced with acetylated polysaccharides (corn starch and microcellulose from Agave Lechuguilla Torr fibers) with different degrees of substitution (DS; 0.44–1.25) at a constant concentration (22% w/w). Tensile strength (0.86–1.34 MPa), elasticity modulus (0.96–1.65 MPa) and elongation at break (14.16–21.66%) increased (p < 0.05) with DS in the reinforcing materials. The moisture content and solubility decreased from 13.17% to 9.81% and from 45.64% to 38.75%, respectively. With increasing DS, water vapor permeability (WVP) decreased by up to 56.4% compared to the control film (unacetylated polysaccharides). The DS of the reinforcing materials did not affect the antioxidant activity. Antibacterial activity against Escherichia coli and Staphylococcus aureus revealed similar inhibition halos for both bacteria, regardless of the DS. Thermogravimetric and calorimetric analysis showed that reinforcing PSI films with acetylated materials improves thermal stability. The results of this research suggest that PSI, a polymer derived from the thermal polymerization of aspartic acid, has significant potential for the development of eco-friendly active packaging for food products. Full article

Amid China’s pursuit of its “dual carbon” goals, systematic theoretical and empirical research remains limited to the potential role of artificial intelligence (AI) in enhancing firms’ carbon emission performance (CEP). From a systems perspective, this study developed a dynamic learning game model that integrates a constant elasticity of substitution (CES) production function, an AI-enabled abatement function, and institutional constraints to analyze firms’ cleaner production and technology adoption under simultaneous budgetary and emission constraints. Empirically, we drew on panel data of 3404 Chinese A-share listed firms from 2013 to 2023 and employ a two-way fixed-effect model to examine the effect of AI empowerment on CEP. The results showed that AI significantly improves CEP overall, though its effect is potentially constrained by energy rebound effects. Robustness checks using alternative measures and specifications confirmed the reliability of the findings and further indicated that AI’s abatement effect became stronger after 2018, consistent with technological maturity and institutional improvement. Mechanism analysis suggests two plausible pathways: (1) improving ESG performance and strengthening environmental governance; and (2) stimulating green innovation to support low-carbon technology development and application. Heterogeneity analysis indicates that AI’s effects are more evident in regions with higher marketization, in private firms, and in non-pollution-intensive industries. By contrast, firms led by executives with overseas experience tend to exhibit weaker effects, a pattern consistent with institutional fit and localization considerations. This study contributes to cleaner production theory by highlighting firm-level mechanisms of AI-enabled carbon governance while offering practical insights for low-carbon transitions and digital decarbonization strategies in developing economies. Full article

Rapid urbanization and industrialization have intensified the contradiction between water scarcity and economic growth. Achieving synergy between economic development and water conservation through taxation and subsidy policies has emerged as a critical research focus. This study develops an extended Computable General Equilibrium (CGE) model incorporating a water resource module to evaluate the impacts of production tax and subsidy policies in Wenling City, Zhejiang Province, China, a typical water-scarce city. By integrating a nested Constant Elasticity of Substitution (CES) production function for various water sources, the model captures the interactions between water supply and industrial output. Six policy scenarios of taxations and subsidies are designed. The impacts on macroeconomic aggregates, industrial output, and water usage are simulated. Results indicate that standalone taxation policies (Water Conservation Taxation Policy A1/Industrial Transformation Taxation Policy B1) reduce water usage by 3.35–3.80% but suppress Gross Domestic Product (GDP) growth by 0.37–0.76%. Among combined policies, the Water Conservation Combined Policy A3 achieves the optimal synergy between water conservation and economic growth, increasing real GDP by 1.00% while reducing water usage by 4.97%. This study reveals that taxation curbs the expansion of water-intensive industries, whereas subsidies redirect production factors toward water-efficient industries. Combining these policies effectively balances water conservation and economic development objectives. This study demonstrates how differentiated tax instruments drive water conservation through industrial transformation, providing a quantitative framework for production tax policy formulation in water-scarce regions. Full article

Given health concerns, oleogels are promising substitutes for saturated fats in food products. An emulsion-templated method was used, employing rapeseed oil and hydroxypropyl methylcellulose (HPMC) as the structuring agent, to produce oleogels. Oil-in-water emulsions (50:50 w/w) were prepared with three HPMC concentrations (1.5, 2.0, and 2.5% w/w) and dried convectively at 60, 70, 80, and 90 °C to obtain oleogels. The emulsions exhibited viscoelastic behaviour with a predominant viscous character, G″ > G′. Drying kinetics showed a constant rate period followed by a falling rate period; the latter was satisfactorily modelled using a diffusion-based approach. All oleogels displayed predominantly elastic behaviour but the characteristics depended on the temperature employed during the drying operation and the HPMC content. The mechanical moduli (G″ and G′) of the oleogels increased significantly with a drying temperature below 80 °C. Higher HPMC content enhanced structural development and thermal stability. Most oleogels exhibited high oil binding capacity (>85%), which increased with the drying temperature and the HPMC content. A correlation was established between the elastic moduli, oil retention, and the hardness of the oleogels. No significant influences of the drying temperature and the polymer concentration on lipid oxidation and colour samples were determined. These results highlight the importance of selecting appropriate drying conditions based on the desired final product properties. Full article

In this study, we explore the impact of land investment introduction on efficiency loss at both the enterprise and urban levels and discuss the role of factor-biased technological progress in minimizing these losses. Using a nested constant elasticity of substitution (CES) production function, we theoretically validate the premise that land investment introduction disrupts the optimal allocation of productive factors and reduces the “threshold selection” effect of land cost, leading to efficiency losses. Empirically, the systematic generalized method of moments (GMM) is applied to analyze panel data from 284 prefecture-level cities in China between 2007 and 2019. The findings reveal that land investment introduction brings about efficiency losses and prolonged land investment strategies that deepen enterprise efficiency loss, while urban efficiency loss may be temporarily alleviated but tends to deepen over the long term. Enterprise efficiency loss can be reduced by selecting land-biased, labor-biased, and capital-biased technological progress; however, its impact on urban efficiency loss remains uncertain. These findings provide insights into the optimal selection of factor-biased technological progress for industrial enterprises and provide policy-oriented recommendations for enhancing production and improving efficiency. Full article

The optimization of taxation and profit maximization constitute two fundamental and interconnected problems, inherently entwined as firms navigate within a given tax framework. Nonetheless, existing literature commonly treats these problems separately, focusing either on optimal taxation or on profit maximization independently. This paper endeavors to unify these problems by formulating a bilevel model wherein the government assumes the role of a leader, and the profit-maximizing monopolist acts as a follower. The model assumes technology given by a constant elasticity of substitution (CES) production function, with market prices following a linear demand curve. Since the solution for a general case with an arbitrary degree of homogeneity cannot be determined explicitly, analytical expressions for the tax revenue function, profit function, optimal tax rates, and optimal input levels are derived for scenarios with degrees of homogeneity set to values 0.5 for decreasing and 1 for constant returns to scale. Several illustrative numerical examples are presented alongside corresponding graphical representations. The last example, with a degree of homogeneity set to value 2, shows that the optimal solution is achievable under monopolist assumption even with increasing returns to scale, a scenario impossible under perfect competition. The paper ends with discussions on sensitivity analysis of the change in the optimal solution with regard to the change in the producer’s price. Full article

The increase in life expectancy has led to a rise of musculoskeletal disorders. Calcium phosphate cements (CPCs), thanks to some amazing features such as the ability to harden in vivo, bioactivity, and resorbability, are promising candidates to treat these diseases, notwithstanding their poor mechanical properties. We aimed to synthesise pure and barium- or silicon-doped brushite-based CPCs loaded with piroxicam to study the effects of the substitution on physical-chemical and pharmaceutical properties before and after cement immersion in phosphate buffer for different time periods. Our results demonstrated that piroxicam became amorphous in the hardened cements. The dopants did not change the brushite structure or its lamellar morphology, while both Ba and Si additions improved the initial Young’s modulus compared to the pure cement, and the opposite trend was observed for compressive strength. Both the compressive strength and the elastic modulus decreased for the samples immersed in solution compared to the non-immersed samples, with stabilisation as the number of days increased. After 7 days, the whole drug amount was released, with a slower and constant kinetic for the Ba-doped cements compared to the pure and Si-doped ones. Full article

This study presents the development of thiol–maleimide/thiol–thiol double self-crosslinking hyaluronic acid-based (dscHA) hydrogels for use as dermal fillers. Hyaluronic acid with varying degrees of maleimide substitution (10%, 20%, and 30%) was synthesized and characterized, and dscHA hydrogels were fabricated using two molecular weights of four-arm polyethylene glycol (PEG10K/20K)–thiol as crosslinkers. The six resulting dscHA hydrogels demonstrated solid-like behavior with distinct physical and rheological properties. SEM analysis revealed a decrease in porosity with higher crosslinker MW and maleimide substitution. The swelling ratios of the six hydrogels reached equilibrium at approximately 1 h and ranged from 20% to 35%, indicating relatively low swelling. Degradation rates decreased with increasing maleimide substitution, while crosslinker MW had little effect. Higher maleimide substitution also required greater injection force. Elastic modulus (G′) in the linear viscoelastic region increased with maleimide substitution and crosslinker MW, indicating enhanced firmness. All hydrogels displayed similar creep-recovery behavior, showing instantaneous deformation under constant stress. Alternate-step strain tests indicated that all six dscHA hydrogels could maintain elasticity, allowing them to integrate with the surrounding tissue via viscous deformation caused by the stress exerted by changes in facial expression. Ultimately, the connection between the clinical performance of the obtained dscHA hydrogels used as dermal filler and their physicochemical and rheological properties was discussed to aid clinicians in the selection of the most appropriate hydrogel for facial rejuvenation. While these findings are promising, further studies are required to assess irritation, toxicity, and in vivo degradation before clinical use. Overall, it was concluded that all six dscHA hydrogels show promise as dermal fillers for various facial regions. Full article

This study investigates the impact of zirconium substitution on the structural, elastic and magnetic properties of CoCr₂O₄ nanoparticles. A series of CoCr_2−xZr_xO₄ nanoparticles, x = 0.00, 0.05, 0.10, 0.15 and 0.20, are synthesized via the co-precipitation method. X-ray diffraction (XRD) patterns affirm the formation of single-phase cubic structure with the space group Fd3m. Special attention is given to accurately calculating the average crystallite size (D) and lattice parameter (a) using Williamson–Hall (W–H) analysis and the Nelson–Riley (N–R) extrapolation function, respectively. The increase in Zr⁴⁺ content leads to a reduction in crystallite size and an increase in the lattice parameter. Elastic properties are estimated from force constants and the lattice constant, determined from FTIR and XRD, respectively. The observed changes in the elastic constants are attributed to the strength of interatomic bonding. The stiffness constants decrease, while Poisson’s ratio increases with increasing Zr⁴⁺ content, reflecting the increase in the ductility of the prepared samples. As the Zr⁴⁺ content increases, the stiffness constants decrease, and Poisson’s ratio increases, reflecting enhanced ductility of the samples. Furthermore, as Zr⁴⁺ content rises, Young’s modulus, the rigidity modulus and Debye temperature decrease. The magnetic hysteresis loop measurements are carried out at room temperature using a vibrating sample magnetometer (VSM) over a field range of 25 kg. Unsubstituted CoCr₂O₄ exhibits ferrimagnetic behavior. As Zr⁴⁺ content increases, saturation magnetization (M_s) and magnetic moment decrease, while remanent magnetization (M_r) and coercivity (H_c) initially decrease up to x = 0.10, then increase with further increases in x. The novel key of this study is how Zr⁴⁺ substitution in CoCr₂O₄ nanoparticles can effectively modify their elastic moduli and magnetic properties, making them suitable for various applications such as flexible electronics, protective coatings, energy storage components and biomedical implants. Full article

The renowned van der Waals (VDW) state equation quantifies the equilibrium relationship between the pressure P, volume V, and temperature $k_{B}T$ of a real gas. We assign new variable interpretations adapted to the economic context: $P\to Y$, representing price; $V\to X$, representing demand; and $k_{B}T\to \kappa$, representing income, to describe an economic state equilibrium. With this reinterpretation, the price elasticity of demand (PED) and the income elasticity of demand (YED) are non-constant factors and may exhibit a singularity of the cusp-catastrophe type. Within this economic framework, the counterpart of VDW liquid–gas phase transition illustrates a substitution mechanism where one product or service is replaced by an alternative substitute. The conceptual relevance of this reinterpretation is discussed qualitatively and quantitatively via several illustrations ranging from transport (carpooling), medical context (generic versus original medication), and empirical data drawn from the electricity market in Germany. Full article