Search Results (72)

This study introduces a novel class of architected foam structures based on triply periodic minimal surface (TPMS) geometries for passive battery thermal management. Unlike conventional cold plates that rely on active pumping or high-conductivity solid materials, the proposed TPMS-like foams leverage convective fluid transport within a lightweight, electrically insulating polymer matrix. We present the design, fabrication, and experimental characterization of Schwarz Primitive TPMS structures manufactured via injection molding using silicone rubber, which has a comparable quality to additively manufactured polymer cold plates but with significantly lower manufacturing complexity and cost. The TPMS cold plates achieve passive fluid circulation without external pumps, reducing parasitic power consumption while maintaining thermal resistance values of approximately 23.5 K/W. Although its thermal resistance is higher than that of an aluminum plate of the same size (2.7 K/W), the TPMS cold plate is electrically insulating and offers additional safety benefits. Additionally, it can be fabricated from and filled with fire-retardant materials to prevent thermal propagation while maintaining a relatively low temperature gradient. Mechanical compression testing of TPMS foam samples with about 30% solid volume fraction showed a compressive strength of 86.2 kPa at 0.2 strain, equivalent to 30.5% of the compressive modulus of solid silicone (282.6 kPa). Compared to solid silicone plates (thermal resistance is 1420 K/W), the TPMS fluid-filled structures reduce thermal resistance by more than two orders of magnitude. This work establishes design rules, fabrication protocols, and performance benchmarks for TPMS-based passive cooling devices, offering a scalable pathway toward safer, lighter, and more energy-dense battery packs. Full article

The formation of asphalt–resin–paraffin deposits (ARPDs) and gas hydrate deposits (GHDs) in oil wells equipped with electric submersible pumps (ESPs) remains a significant challenge in the oil and gas industry. This study aims to develop an inhibitory technology to prevent these deposits by utilizing the synergistic effect of chemical reagents combined with the optimization of ESP operating parameters. Based on previously published mathematical modeling and laboratory studies by the authors, this work presents the technological implementation of the inhibition system and its economic assessment. Specifically, optimal reagent dosages were calculated considering their synergistic interactions, a periodic injection regime was established, and the impact on the well’s mean time between failures (MTBF) was evaluated. Results demonstrate that optimizing ESP parameters shifts the onset depth of GHD formation by 119.4 m (25%) and ARPD formation by 72.6 m (6%). The application of the selected ARPD inhibitor at 0.055 wt.% reduced the thermodynamic hydrate inhibitor (methanol) dosage by 12.17% and enabled a transition from continuous to periodic methanol injection. Consequently, the predicted MTBF increased from 277 to 419 days (+50%). An eight-year economic analysis showed a positive net present value with a payback period of 14 months. Thus, the proposed technology is recommended for field testing in high-paraffin, low-resin oil fields operating under permafrost conditions. Full article

Hydrogen blending into natural gas grids can support early renewable hydrogen deployment, but admissible injection depends on local gas flow, blending limits, and upstream hydrogen concentrations. This paper analyses these effects for a regional high-pressure gas-grid section in Styria, Austria, with two hydrogen injection points. A transient gas-network model derives time- and location-dependent injection limits, which are integrated into an electrolyser dispatch optimisation with fixed trailer demand and annual gas-grid injection demand. Three cases are compared: unrestricted injection, a “CH₄-based” limit without upstream hydrogen, and an “H₂-aware” case representing potential upstream hydrogen injection. For the analysed configuration, blending constraints shift operation away from favourable electricity-price periods, particularly when low prices coincide with reduced gas demand. In the 2025 reference case, the “H₂-aware” constraint increases the electricity-cost contribution from 4.22 to 5.45 EUR/kg_H2. A robustness analysis using electricity-price series for 2020, 2022, and 2025 shows that the “H₂-aware” constraint increases the electricity-cost contribution by 15.8–29.1% relative to unrestricted injection. The results demonstrate that dynamic gas-grid constraints should be considered when assessing blending-based electrolyser projects, while the quantitative findings remain specific to the analysed network and assumptions. Full article

Grid-connected photovoltaic–battery energy storage–electric vehicle (PV-BESS-EV) charging stations require supervisory energy management that can coordinate tariff response, carbon-intensity signals, peak constraints, storage utilization, and converter-level operability within a transparent evidential framework. This study develops a bounded-reference rule-based supervisory energy management system (RB-SEMS) that preserves lower-level local converter controllers while generating operating modes and saturated reference commands for BESS power, grid exchange, and EV charging limits. A dual-time-scale evaluation framework is established by combining short-time switching/control simulations for dynamic traceability and SOC-sensitive protection with 24 h, 15 min EMS-level energy-balance simulations for cost, carbon, peak, PV utilization, EV service, and storage throughput assessment. Selected daily reference-injection cases are retained as copied-model diagnostic checks rather than as full-day switching-level validation. Under the D4-LSOC condition, RB-SEMS reduces the reported post-startup DC-bus deviation from 46.13 V to 40.60 V and the filtered BESS peak from 269.18 kW to 84.42 kW. In the E1-TOU scenario, E1-TOU-cost reduces daily total cost from 623.57 CNY to 564.05 CNY, lowers peak-period grid import from 183.75 kWh to 126.75 kWh, and increases local PV utilization from 71.13% to 78.71%; E1-PC66 further reduces the maximum 15 min grid import from 77.88 kW to 66.00 kW. Under the prescribed E2-PCC scenario, E2-CP reduces the calculated grid-related CO₂ emissions from 550.29 kg to 500.42 kg, whereas the price-only diagnostic increases them to 572.29 kg. Same-metric PV-SC and MILP comparisons, tested-range sensitivity analysis, and a throughput-based degradation proxy clarify that RB-SEMS is an interpretable supervisory baseline for cost–carbon–peak–cycling trade-off analysis rather than a cost-optimal controller or regionally validated proof of carbon reduction. Full article

We demonstrate a reconfigurable microwave frequency measurement (MFM) scheme based on the period-one (P1) dynamics of an optically injected semiconductor laser. Unlike conventional architectures relying on electrical frequency-sweeping, our approach utilizes the P1 oscillation to generate a wideband linear optical chirp. A spectral gating mechanism is introduced, where an optical bandpass filter creates a negative temporal marker by rejecting free-running component of distributed feedback laser (DFB), thereby eliminating the need for external synchronization or pilot tones. The measurement range is flexibly tunable by adjusting the injection parameters, enabling a measurement range from 10 to 48 GHz. Experimental results demonstrate a frequency resolution of 50 MHz with chirp rate of 1 GHz/μs and a root-mean-square (RMS) error below 15 MHz, confirming the validity of this all-optical, self-referenced frequency-to-time mapping technique. Full article

The output voltage harmonics of electric vehicle (EV) charging converters directly affect grid power quality. This paper proposes a harmonic analysis method based on geometric algebra (GA), which employs a multivector representation of signals and least squares estimation to accurately extract fundamental, integer-order, and inter-harmonics. A coupling coefficient is defined to quantify the phase correlation between frequency components. Based on measured data, harmonic characteristics under four typical operating conditions are analyzed, and an adaptive PID controller is designed to dynamically adjust the virtual resistance for harmonic suppression. The results show that the GA method significantly reduces spectral leakage under non-integer-period sampling conditions, with amplitude estimation errors below ±2%. The total harmonic distortion (THD) decreases with increasing active power and increases with reactive power injection. The droop coefficient exhibits a non-monotonic effect, while reducing the proportional gain raises the THD. Adaptive control reduces the average THD by 14.0–28.5% with a total response time of less than 0.05 s. The coupling coefficient $C_{13}$ is strongly positively correlated with THD and negatively correlated with the maximum Lyapunov exponent computed using the Rosenstein small-data method (correlation coefficient −0.85), confirming the intrinsic relationship between coupling and stability. Compared with fast Fourier transform (FFT) and other methods, GA achieves higher accuracy under short data records and non-integer-period sampling. This paper provides a complete theoretical framework and engineering solution for harmonic suppression in charging converters. Full article

The rapid growth of residential photovoltaic (PV) installations has increased interest in electrical storage units (ESUs) as a means of enhancing self-consumption and reducing surplus electricity fed into the grid. However, in temperate climates characterized by strong seasonal variability in solar generation, the economic viability of residential battery storage remains uncertain. This study examines whether ESUs provide measurable financial benefits under such climatic conditions, particularly after the transition from net-metering to net-billing schemes. The analysis combines empirical household electricity consumption data with simulation-based modeling of PV–battery operation. Periods of surplus energy production during high solar generation were taken into account, as well as periods of increased energy demand in the winter season and technical limitations related to energy storage, including the difference between actual and nominal capacity of energy storage systems. The results indicate that although battery storage increases self-consumption and reduces grid injection during peak generation periods, its economic performance is limited by the seasonal mismatch between electricity production and demand. Consequently, under net-billing conditions, residential ESUs do not automatically ensure economic profitability in temperate climates. Full article

This paper addresses the optimal management of photovoltaic (PV) systems and distribution static synchronous compensators (D-STATCOMs) in modern electrical distribution networks. A mixed-integer nonlinear programming (MINLP) model is formulated which co-optimizes device placement, sizing, and multi-period dispatch to minimize the total annualized system costs while satisfying AC power flow and operational constraints. To solve this challenging problem, a decomposition methodology is proposed, wherein the binary location decisions for the PVs and D-STATCOMs are treated as predefined inputs, upon the basis of site selections commonly reported in the literature. With the integer variables fixed, the problem is reduced to a continuous nonlinear programming (NLP) subproblem for optimal capacity sizing and operational scheduling, which is solved using the interior point optimizer (IPOPT) via the Julia/JuMP environment. The core contribution of this work lies in its comprehensive demonstration of the economic superiority of variable reactive power injection over conventional fixed compensation schemes. Through numerical validation on standard 33- and 69-bus test systems, it is shown that a variable D-STATCOM operation yields substantial and consistent economic gains. Compared to optimized fixed-injection solutions, variable injection provides additional annual savings averaging USD 120,516 (33-bus feeder) and USD 125,620 (69-bus grid), corresponding to a further 3.4% reduction in total costs. These benefits prove robust across different device location sets identified by various metaheuristic algorithms, and they scale effectively to larger network topologies. The results demonstrate that transitioning to variable power injection is not merely an incremental improvement but a fundamental advancement for achieving techno-economic optimality in distribution system planning. The proposed methodology provides utilities with a computationally efficient framework for determining near-optimal PV and D-STATCOM management strategies by first fixing deployment locations based on established planning insights and then rigorously optimizing sizing and dispatch, in order to maximize economic returns while ensuring reliable network operation. Full article

Background: Noninvasive transdermal insulin delivery using ultrasound technology has gained attention for improving the glycemic control of insulin-dependent patients. Methods: Indirect functional comparison and evaluation of insulin dosage, between noninvasive ultrasound-mediated transdermal delivery and needle injection methods, was achieved utilizing in vivo blood glucose measurements of temporary hyperglycemic rabbits. Nine rabbits were divided into three groups: (i) untreated control, (ii) subcutaneous injection and (iii) ultrasound-mediated transdermal delivery. Animals were anesthetized using a combination of ketamine hydrochloride and sodium xylazine to produce temporary hyperglycemic rabbits during the experiments. The rabbits in the control group did not receive insulin, while the animals in the ultrasound group received insulin transdermally for 10 min utilizing a customized single-element piston-shaped ultrasound transducer operated by multi-frequency electrical signals from 100 to 200 kHz. Rabbits in the direct subcutaneous injection group were anesthetized and injected with 0.25 units/kg of insulin. Results: With an initial blood glucose baseline level of 228.7 ± 13.1 (mg/dL) for all rabbits, the in vivo results of control group showed an increase above the baseline by 129.7 ± 27.3 (mg/dL) at the end of the in vivo experimental period (80 min). However, the ultrasound-mediated delivery and subcutaneous injection groups showed noticeable statistically significant percentage reductions in blood glucose levels by 43.9 ± 5.4 and 42.7 ± 6.6, respectively, compared to the control group by the end of the in vivo experiments. Conclusions: In vivo glucose response results confirmed that piston-shaped ultrasound transducers achieved indirectly similar insulin dosage delivery by ultrasound energy for tested animals with no statistically significant differences once compared to the results of the subcutaneous needle injection group. Full article

The increasing penetration of intermittent renewable energy demands innovative solutions to maintain grid stability, resilience, and security in the body of smart cities. This paper presents a novel framework that redefines Bitcoin mining as a form of virtual energy storage, a flexible and controllable load capable of delivering large-scale demand response services, positioning it as a competitive alternative to traditional energy storage systems, including electrical, mechanical, thermal, chemical, and electrochemical storage solutions. By strategically aligning mining activities with grid conditions, Bitcoin mining can absorb excess electricity during periods of oversupply, converting it into digital assets, and reduce operations during times of scarcity, effectively emulating the behavior of conventional energy storage systems without the associated capital expenditures and material requirements. Beyond its operational flexibility, this paper explores the cyber–physical benefits of integrating Bitcoin mining into the power transmission systems as a defensive mechanism against false data injection (FDI) cyberattacks in smart city infrastructure. To achieve this goal, a decentralized and adaptive control strategy is proposed, in which mining loads dynamically adjust based on authenticated grid-state information, thereby improving system observability and hindering adversarial efforts to disrupt state estimation. In addition, to handle the proposed approach, this paper introduces a high-performance algorithm, a combination of quantum-augmented particle swarm optimization and wavelet-oriented whale optimization (QAPSO-WOWO). Simulation results confirm that strategic deployment of mining loads improves grid sustainability by utilizing curtailed renewables, enhances resilience by mitigating load-generation imbalances, and bolsters cybersecurity by reducing the impacts of FDI attacks. This work lays the foundation for a transdisciplinary paradigm shift, positioning Bitcoin mining not as a passive energy consumer but as an active participant in securing and stabilizing the future power grid in smart cities. Full article

This study investigates a water–energy investment in the Consorzio di Bonifica della Romagna Occidentale (Northern Italy) over the period 2015–2022, analysing how integrated irrigation and energy infrastructures can support agricultural resilience. In this area, pressurised irrigation systems are increasingly replacing traditional gravity-fed networks, enabling precise water distribution. However, their energy intensity raises operational costs and exposure to volatile electricity prices. To address these challenges, the research evaluates the coupling of pressurised irrigation with floating photovoltaic (PV) systems on irrigation reservoirs. Using plot-level economic data for vineyards and orchards, the analysis shows that, although pressurised systems entail higher costs in terms of Relative Water Cost (RWC) and Economic Water Productivity Ratio (EWPR), integrating them with PV production significantly improves economic performance. The findings show an average reduction in RWC of 1.44% for vineyards and 5.52% for orchards, and an average increase in EWPR of 38.51 units for vineyards and 24.81 units for orchards. This suggests that combining efficient irrigation systems with renewable energy could represent a viable pathway toward more sustainable water management. Policy implications may concern incentives for joint water–energy investments, adjustments to zero-injection rules, and broader reforms in agricultural, energy, and environmental policies. Full article

This study presents an innovative modification to the chemical bath deposition method for synthesizing zinc oxide thin films by incorporating a high-voltage electric field, with and without electrical polarity inversion, to influence film growth dynamics. Two configurations were developed to assess the effects of electric field strength, periodic inversion, air agitation, and solution pH on the morphological, structural, and optical properties of ZnO coatings. Morphology studies revealed that particle size, shape, and distribution were strongly dependent on synthesis parameters, with electric field and air injection enabling higher surface coverage and finer nanostructures. Crystalline structural analysis confirmed the formation of the wurtzite ZnO phase, with reduced interplanar spacing and crystallite size under electric fields, especially when polarity was inverted. Optical measurements showed a consistent increase in the band gap (blue shift) and reduced defect-related absorption when electric field is applied. These findings are evidence that controlled electric field application during chemical bath deposition enables precise tuning of ZnO film properties. Full article

Multiphase electric drives (EDs) offer important advantages for high-demand applications. However, they require appropriate high-performance control strategies. In this context, finite-control-set model predictive control (FCS-MPC) emerges as a promising strategy, offering a notable flexibility to implement multiobjective regulation schemes. When applied to multiphase EDs, standard FCS-MPC exhibits degraded current quality at low and medium control frequencies. Multivector solutions address this issue by properly combining multiple voltage vectors within a single control period to create the so-called virtual voltage vectors (VVVs). In this way, this approach achieves flux and torque regulation while minimizing current injection into the secondary subspace. For this purpose, the VVV synthesis typically prioritizes active vectors with low contribution in secondary subspaces, avoiding the average deception phenomenon. VVV solutions commonly enable an open-loop regulation of secondary currents. Nevertheless, the absence of closed-loop control in the secondary subspace hinders the compensation of nonlinearities, machine asymmetries, and unbalanced conditions in the ED. Considering this scenario, this work implements a multivector FCS-MPC recovering closed-loop control for the secondary subspace. The capability of the proposal to mitigate secondary current injection and compensate for possible dissymmetries is experimentally evaluated in a six-phase ED. Its performance is compared against a benchmark technique in which secondary current regulation is handled in open-loop mode. The proposed control solution significantly improves in current quality, achieving a reduction in harmonic distortion of 54% at medium speed. Full article

The presented research examined the impact of using biodiesel as a fuel for existing diesel engines during the transition to the broader adoption of electric vehicles powered by renewable energy or through integrated hybrid drive systems. The authors considered previous research on this topic, which is demonstrated by a literature review. This paper will utilize the findings to further explore the potential of optimizing existing engines by using biodiesel and thus propose their continued use in the transition period as one of the clean fuels. This paper outlines the standards that define fuel quality and presents a test bench equipped with an experimental engine and specialized equipment for laboratory examination, enabling the measurement of emissions and the determination of cylinder pressure. To ensure the repeatability of the experimental conditions and facilitate future comparison of the obtained results, the engine examination was conducted according to the standard ESC 13-mode test. The examination process confirmed a significant reduction in particulate matter emissions (on average 40%) but, simultaneously, an increase in nitrogen oxide emissions (on average 25%), whose level, according to data from the literature, depends on the type of raw materials used for biodiesel production. Brake thermal efficiency is higher when operating with biodiesel (on average 1.5%). Still, it was concluded that the use of biodiesel in existing diesel engines is feasible only if the engines are equipped with variable systems for automatically adjusting the compression ratio, fuel injection time, valve timing, and so on. The outcomes from the examination conducted can be further processed by applying statistical methods and represent an essential database for further research in this scientific area. Full article

With the acceleration of the oilfield development process during the high water content period, the contradiction between the increase in energy consumption and the decrease in the energy efficiency of the gathering and transportation system has become increasingly obvious. This paper develops a grey relational analysis model using a combination of AHP and EWM. Based on the characteristics of light oil production, a four-level evaluation indicator system is developed. Based on game theory, AHP can provide subjective weights, the EWM can provide objective weights, and subjective and objective combinations are used for a more reasonable assignment. Concurrently, the 0.05 distinguishing coefficient and the ideal reference values are selected as the GRA reference sequence to evaluate the energy consumption of the gathering and transportation system as a whole and each subsystem. The analysis of a light oil block indicates significant room for improvement in the energy efficiency correlation across the system. Taking the central processing station as an example, the grey relational degree of electricity consumption per unit of injected water is measured at 0.12, marking it as the weakest link in the system. This study supports efficiency enhancement by identifying energy consumption bottlenecks within the system. Full article