Search Results (65)

This study investigates the impact of environmental, social, and governance (ESG) disclosure on value creation in a balanced panel of 100 non-financial Sharia-compliant firms listed on the Saudi Stock Exchange over the period 2014–2023. The analysis employs a combination of econometric techniques, including fixed effects models with Driscoll–Kraay standard errors, Pooled Ordinary Least Squares (POLS) with Driscoll–Kraay standard errors and industry and year dummies, and two-step system generalized method of moments (GMM) estimation to address potential endogeneity and omitted variable bias. Value creation is measured using Tobin’s Q (TBQ), Return on Assets (ROA), and Return on Equity (ROE). The models also control for firm-specific variables such as firm size, leverage, asset tangibility, firm age, growth opportunities, and market capitalization. The findings reveal that ESG disclosure has a positive and statistically significant effect on firm value across all three performance measures. Furthermore, firm size significantly moderates this relationship, with larger Sharia-compliant firms experiencing greater value gains from ESG practices. These results align with agency, stakeholder, and signaling theories, emphasizing the role of ESG in enhancing transparency, reducing information asymmetry, and strengthening stakeholder trust. The study provides empirical evidence relevant to policymakers, investors, and firms striving to achieve Saudi Arabia’s Vision 2030 sustainability goals. Full article

In this research, an analysis of the thermomagnetic properties of a nanoscale spin-2 and spin-3/2 system is conducted. This system is modeled with as a quasi-spherical Ising-type nanoparticle with a diameter of 2 nm, in which atoms with spin-2 and spin-3/2 configured in body-centered cubic (BCC) lattices interact within their relevant nanostructures. To determine the thermomagnetic behaviors of the nanoparticle, numerical simulations using Monte Carlo techniques and thermal bath class algorithms are performed. The results exhibit the effects of exchange couplings ($J_1,J_2^{\prime }$), magnetocrystalline anisotropies ($D_{3/2}^{\prime },D_2^{\prime }$), and external magnetic fields ($h^{\prime }$) on the finite-temperature phase diagrams of magnetization ($M_T$), magnetic susceptibility (${\chi }_T$), and thermal energy ($k_B{T}^{\prime }$). The influences of the exchange, anisotropic, and external field parameters are clearly reflected in the compensation, hysteretic, and pseudocritical phenomena presented by the quasi-spherical nanoparticle. When the parameter reflecting ferromagnetic second-neighbor exchanges in the nanosphere ($J_2^{\prime }$) increases, for a given value of the external magnetic field, the compensation ($T_{comp}$) and pseudocritical ($T_{pc}$) temperatures increase. Similarly, in the ranges $0<J_2^{\prime }⩽4.5$ and $-15⩽h^{\prime }⩽15$ at a specific temperature, an increase in $J_2^{\prime }$ results in the appearance of exchange anisotropies (exchange bias) and and increased hysteresis loop areas in the nanomodel. Full article

The growth in the adoption of circular economy principles in the construction industry has given rise to material passports as a critical implementation tool. Given the existing problems of high resource use and high waste generation in the construction industry, there is a pressing need to adopt novel strategies and tools to mitigate the adverse impacts of the built environment. However, research on the application of material passports in the context of construction waste management remains limited. The aim of this paper is to identify the contextual uses, stakeholders, requirements, and challenges in the application of material passports for managing waste generated from building construction and demolition processes through a systematic review approach. Comprehensive searches in Scopus and the Web of Science databases are used to identify relevant papers and reduce the risk of selection bias. Thirty-five (35) papers are identified and included in the review. The identified key contexts of use included buildings and cities as material banks, waste management and trading, and integrated digital technologies. Asset owners, waste management operators, construction and deconstruction teams, technology providers, and regulatory and sustainability teams are identified as key stakeholders. Data requirements related to material, components, building stock data, lifecycle, environmental impact data, and deconstruction and handling data are critical. Moreover, the key infrastructure requirements include modeling and analytical tools, collaborative information exchange systems, sensory tracking tools, and digital and physical storage hubs. However, challenges with data management, costs, process standardization, technology, stakeholder collaboration, market demand, and supply chain logistics still limit the implementation. Therefore, it is recommended that future research be directed towards certification and standardization protocols, automation, artificial intelligence tools, economic viability, market trading, and innovative end-use products. Full article

This study assesses the potential impact of climate change on hydropower generation, focusing on the Grand Inga hydropower project on the Congo River in the Democratic Republic of Congo. Utilizing a multi-input approach with a conceptual HEC-HMS hydrologic model, this research incorporates a new bias-corrected high-resolution daily downscaled dataset, NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP CMIP6), and its predecessor (CMIP5) under various climate scenarios. The hydropower generation at Inga Falls is simulated using a hydropower model, considering observed and simulated daily flows for different climate models and emission scenarios. The results suggest that the Grand Inga project will be resilient to negative climate impacts during its initial phases (1–5). The system demonstrates security and insensitivity to adverse changes, both for existing (Phase 1–2) and planned (Phase 3–5) hydropower components. This study indicates that climate change effects become apparent only in later phases (6–8), with predominantly positive impacts, potentially increasing the generation potential of the hydropower system. Overall, the Grand Inga hydropower project appears robust against adverse climate influences throughout the majority of its development phases. Full article

Bias instability is one of the most critical factors in the performance of spin-exchange relaxation-free (SERF) co-magnetometers. Previous studies on SERF co-magnetometers have shown that changes in the atomic ensemble temperature can lead to variations in the alkali metal atom density, which in turn affect the optical rotation angle and light shift, ultimately influencing the system’s stability. Building on this understanding, this paper introduces the thermoelectric analogy method for the first time in the transient heat transfer analysis of SERF co-magnetometer atomic ensembles. Using this method, the primary factors affecting the atomic ensemble temperature in a SERF co-magnetometer were analyzed, and transient heat transfer models were established for the following processes: the interaction between the non-magnetic electric heating system and the atomic ensemble temperature, laser heating of the atomic ensemble by the optical system, and the effect of environmental temperature changes on the non-magnetic electric heating system. These models were experimentally validated through active temperature variation experiments. The experimental results show that the proposed transient heat transfer models accurately describe the related heat transfer processes of the atomic ensemble, with model fitting accuracy exceeding 98%. This lays a solid foundation for the high-precision closed-loop control of the atomic ensemble temperature in SERF co-magnetometers and provides valuable insights for the structural design and engineering applications of SERF co-magnetometers. Full article

The exchange bias (EB) effect denotes a magnetic bias phenomenon originating from the interfacial exchange coupling at the ferromagnetic/antiferromagnetic materials, which plays an indispensable role in the functionality of various devices, such as magnetic random-access memory (MRAM) and sensors. Voltage control of exchange bias offers a promising pathway to significantly reduce device power consumption, effectively fostering the evolution of low-energy spintronic devices. The “magneto-ionic” mechanism, characterized by its operational efficiency, low energy consumption, reversibility, and non-volatility, provides innovative approaches for voltage control of exchange bias and has led to a series of significant advancements. This review systematically synthesizes the research progress on voltage control of exchange bias based on the magneto-ionic mechanism from the perspectives of ionic species, material systems, underlying mechanisms, and performance parameters. Furthermore, it undertakes a comparative evaluation of the voltage-controlled exchange bias by different ions, ultimately providing a forward-looking perspective on the future trajectory of this research domain. Full article

The refractive index change obtained after annealed proton exchange (APE) in lithium niobate (LiNbO₃) crystals depends on both the proton exchange process carried out in hot acid and the structure of the crystals. In devices produced by the APE method, dislocations and lattice defects within the crystal structure are considered to be primary contributors to refractive index discontinuities and waveguide instability. In this study, the effects of pre-annealing LiNbO₃ crystals at 500 °C on multifunctional integrated optical chips (MIOCs) were investigated through interferometric fiber-optic gyroscope (IFOG) system-level tests. It was observed that the pre-annealing process resulted in an improvement in the optical throughput of MIOCs (from %34 to %51) and the temperature-dependent bias drift stability of the IFOG (from 0.031–0.038°/h to 0.012–0.019°/h). The angle random walk (ARW) was measured as 0.0056 deg/√h. Full article

Monocular depth estimation provides low-cost environmental information for intelligent systems such as autonomous vehicles and robots, supporting sustainable development by reducing reliance on expensive, energy-intensive sensors and making technology more accessible and efficient. However, in practical applications, monocular vision is highly susceptible to adverse weather conditions, significantly reducing depth perception accuracy and limiting its ability to deliver reliable environmental information. To improve the robustness of monocular depth estimation in challenging weather, this paper first utilizes generative models to adjust image exposure and generate synthetic images of rainy, foggy, and nighttime scenes, enriching the diversity of the training data. Next, a channel interaction module and Multi-Scale Fusion Module are introduced. The former enhances information exchange between channels, while the latter effectively integrates multi-level feature information. Finally, an enhanced consistency loss is added to the loss function to prevent the depth estimation bias caused by data augmentation. Experiments on datasets such as DrivingStereo, Foggy CityScapes, and NuScenes-Night demonstrate that our method, CIT-Depth, exhibits superior generalization across various complex conditions. Full article

This study explores the potential of β-SnSe monolayers as a promising material for ozone (O₃) sensing using density functional theory (DFT) combined with the non-equilibrium Green’s function (NEGF) method. The adsorption characteristics of O₃ molecules on the β-SnSe monolayer surface were thoroughly investigated, including adsorption energy, band structure, density of states (DOSs), differential charge density, and Bader charge analysis. Post-adsorption, hybridization energy levels were introduced into the system, leading to a reduced band gap and increased electrical conductivity. A robust charge exchange between O₃ and the β-SnSe monolayer was observed, indicative of chemisorption. Recovery time calculations also revealed that the β-SnSe monolayer could be reused after O₃ adsorption. The sensitivity of the β-SnSe monolayer to O₃ was quantitatively evaluated through current-voltage characteristic simulations, revealing an extraordinary sensitivity of 1817.57% at a bias voltage of 1.2 V. This sensitivity surpasses that of other two-dimensional materials such as graphene oxide. This comprehensive investigation demonstrates the exceptional potential of β-SnSe monolayers as a highly sensitive, recoverable, and environmentally friendly O₃ sensing material. Full article

The ground state of correlated electrons in complex oxide films can be controlled by applying epitaxial strain, offering the potential to produce unexpected phenomena applicable to modern spintronic devices. In this study, we demonstrate that substrate-induced strain strongly affects the coupling mode of interfacial magnetic moments in a ferromagnetic (FM)/antiferromagnetic (AFM) system. In an epitaxial bilayer comprising AFM LaFeO₃ (LFO) and FM La_0.7Sr_0.3MnO₃ (LSMO), samples grown on a LaAlO₃ (LAO) substrate exhibit a larger exchange bias field than those grown on a SrTiO₃ substrate. Our results indicate a transition in the alignment of magnetic moments from perpendicular to collinear due to the large compressive strain exerted by the LAO substrate. Collinear magnetic moments at the LSMO/LFO interface generate strong exchange coupling, leading to a considerable exchange bias effect. Thus, our findings provide a method for tailoring and manipulating the orientations of magnetic moments at the FM/AFM heterogeneous interface using strain engineering, thereby augmenting methods for exchange bias generation. Full article

Electrical load dynamics result in system instability if not met with adequate power generation. Therefore, monitoring and control plans are necessary to avoid potential consequences. Tie-line-bias control has facilitated power exchange between interconnected areas to cope with load dynamics. However, this approach presents a challenge, as load variation in either area leads to frequency deviations and power irregularities in each of the interconnected areas, which is undesirable. The load frequency control loop method is used to address this issue, which utilizes area control errors. This study focuses on the control of inter-area oscillations in a six-area power system under the effect of renewable energy sources. It evaluates the area control errors in response to changes in load and the penetration of renewable energy into the system. To mitigate these errors efficiently, an adaptive-PID controller is proposed, and its results are compared with PI and PID controllers optimized with heuristic and meta-heuristic algorithms. The findings demonstrate the superiority of the proposed controller over traditional controllers in mitigating tie-line power errors and frequency deviations in each area of the interconnected power system, thus helping to mitigate inter-area oscillations and restore system stability. Full article

Antiferromagnetic/ferromagnetic (AF/F) systems have been extensively investigated due to the importance that interfacial exchange coupling effects have in the development of magnetic storage technologies. Recently, these systems have garnered interest for the potential they have to imprint the magnetic moments of the AF into an F layer, offering the possibility of using it as a read-out mechanism in antiferromagnetic spintronics. In this study, we explored the importance of crystalline orientation and strains induced by the substrate in the exchange coupling properties of NiO/FeCo AF/F bilayers. For that, we have grown NiO/FeCo bilayers on MgO (001) and Al₂O₃ (0001) substrates varying the FeCo layer thickness. In addition, we have analyzed both deposited samples and those with induced interfacial unidirectional anisotropy. For inducing such interfacial anisotropy, we used a field cooling procedure, heating the bilayers to 650 K and subsequently cooling down to room temperature under the presence of an external magnetic field of 300 mT. We have investigated the effect of the substrate in terms of crystalline orientation and lattice mismatching on the AF/F exchange coupling as well as the dependence of the coercivity and exchange bias on the inverse F layer thickness that is consistent with the interfacial origin of the AF/F exchange coupling. Moreover, the angular dependence of the magnetic properties was explored by using vectorial Kerr magnetometry, confirming the presence of both magnetocrystalline anisotropy, arising from the epitaxial character of the growing process mainly when the bilayer is grown on MgO (001) substrates, and the field cooling (FC)-induced unidirectional anisotropy. Full article

This study focused on comparing metabolic thresholds derived from local muscle oxygen saturation (SmO₂) signals, obtained using near-infrared spectroscopy (NIRS), with global pulmonary ventilation rates measured at the mouth. It was conducted among various Age Groups within a well-trained cyclist population. Additionally, the study examined how cycling performance characteristics impact the discrepancies between ventilatory thresholds (VTs) and SmO₂ breakpoints (BPs). Methods: Junior (n = 18) and Senior (n = 15) cyclists underwent incremental cycling tests to assess their aerobic performance and to determine aerobic (AeT) and anaerobic (AnT) threshold characteristics through pulmonary gas exchange and changes in linearity of the vastus lateralis (VL) muscle SmO₂ signals. We compared the relative power (Pkg) at ventilatory thresholds (VTs) and breakpoints (BPs) for the nondominant (ND), dominant (DO), and bilaterally averaged (Avr) SmO₂ during the agreement analysis. Additionally, a 30 s sprint test was performed to estimate anaerobic performance capabilities and to assess the cyclists’ phenotype, defined as the ratio of P@VT2 to the highest 5 s sprint power. Results: The P_kg@BP for Avr SmO₂ had higher agreement with VT values than ND and DO. Avr SmO₂ P_kg@BP1 was lower (p < 0.05) than P_kg@VT1 (mean bias: 0.12 ± 0.29 W/kg; Limits of Agreement (LOA): −0.45 to 0.68 W/kg; R² = 0.72) and mainly among Seniors (0.21 ± 0.22 W/kg; LOA: −0.22 to 0.63 W/kg); there was no difference (p > 0.05) between Avr P_kg@BP2 and P_kg@VT2 (0.03 ± 0.22 W/kg; LOA: −0.40 to 0.45 W/kg; R² = 0.86). The bias between two methods correlated significantly with the phenotype (r = −0.385 and r = −0.515 for AeT and AnT, respectively). Conclusions: Two breakpoints can be defined in the NIRS-captured SmO₂ signal of VL, but the agreement between the two methods at the individual level was too low for interchangeable usage of those methods in the practical training process. Older cyclists generally exhibited earlier thresholds in muscle oxygenation signals compared to systemic responses, unlike younger cyclists who showed greater variability and no significant differences in this regard in bias values between the two threshold evaluation methods with no significant difference between methods. More sprinter-type cyclists tended to have systemic VT thresholds earlier than local NIRS-derived thresholds than athletes with relatively higher aerobic abilities. Full article

This work presents the results of a study that used a model based on rough set theory (RST) to assess the brine temperature of vertical ground heat exchangers (VGHEs) to feed heat pumps (HP). The purpose of this research was to replace costly brine temperature measurements with a more efficient approach. The object of this study was a public utility building located in Poland in a temperate continental climate. The building is equipped with a heating system using a brine–water HP installation with a total capacity of 234.4 kW, where the lower heat source consists of 52 vertical ground probes with a total length of 5200 m. The research was conducted during the heating season of 2018/2019. Based on the data, the heat energy production was determined, and the efficiency of the system was assessed. To predict the brine temperature from the lower heat source, a model based on RST was applied, which allows for the analysis of general, uncertain, and imprecise data. Weather data, such as air temperature, solar radiation intensity, degree days of the heating season, and thermal energy consumption in the building, were used for the analysis. The constructed model was tested on a test dataset. This model achieved good results with a Mean Absolute Percentage Error (MAPE) of 12.2%, a Coefficient of Variation Root Mean Square Error (CV RMSE) of 14.76%, a Mean Bias Error (MBE) of −1.3%, and an R-squared (R²) value of 0.98, indicating its usefulness in estimating brine temperature. These studies suggest that the described method can be useful in other buildings with HP systems and may contribute to improving the efficiency and safety of these systems. Full article

Bimetallic FeCo and FeNi nanoparticles attract much attention due to their promising magnetic properties and a wide range of practical applications as recording and storage media, catalytic systems in fuel cells, supercapacitors, lithium batteries, etc. In this paper, we propose an original approach to the preparation of FeCo- and FeNi/N-doped carbon nanocomposites by means of a coupled process of frontal polymerization and thermolysis of molecular co-crystallized acrylamide complexes. The phase composition, structure, and microstructure of the resulting nanocomposites are studied using XRD, IR spectroscopy, elemental and thermal analysis, and electron microscopy data. The main magnetic characteristics of the synthesized nanocomposites, including the field dependences and the ZFC-FC curves peculiarities, are studied. It is shown that the obtained FeCo/N-C nanocomposites exhibit exchange bias behavior at low temperatures. In turn, FeNi/N-C nanocomposites are ferromagnetically ordered. Full article