Search Results (216)

Assessing and optimizing regional ecological networks is critical for mitigating fragmentation-driven ecological risks and informing evidence-based territorial spatial planning in China. In this study, we developed a comprehensive evaluation framework integrating ecosystem services, ecological sensitivity, and landscape connectivity to identify ecological sources in Anyang City, China. We then extracted ecological corridors and nodes using circuit theory and constructed the city’s ecological network. Notably, we applied complex network theory combined with topological robustness analysis for optimization to enhance network stability. The analysis identified 43 ecological sources (820.72 km²; 11.16% of the region), predominantly distributed in western Anyang. A total of 82 corridors (460.35 km), 62 pinch points, and 120 barrier points were mapped—primarily in the west, revealing critical connectivity deficits. Network optimization through the addition of 10 strategic corridors significantly enhanced structural balance and functionality, with average degree, closeness centrality, clustering coefficient, eigenvector centrality, and graph density increasing by 5.55–12.19%, and their standard deviations decreasing by an average of 19.32%. Global efficiency (+8.74%), the largest connected component ratio (+0.73%), and node/edge recovery robustness (+17.44%/+18.08%) also improved markedly, confirming greater connectivity and resilience. Our methodology comprehensively integrates ecosystem functional services, disturbance resistance, and spatial structural stability, providing a practical reference for the construction and optimization of regional ecological networks in mountainous–plain transition zones of China. Full article

Biodiesel is a promising, sustainable alternative to fossil fuels such as petrol and diesel. Currently, biodiesel can be produced from edible plant oils and non-edible sources and wastes. Notably, fish waste oil is a sustainable resource for transesterification reactions to produce biodiesel. This research proposes a general process design methodology to investigate the potential of biodiesel production from fish waste oil as a pathway for waste-to-energy. The methodology integrates Pinch Analysis principles and process simulation to optimize the energy efficiency of a process design. Real data are collected on fish waste from fish industries in Egypt, focusing on three regions in northern Egypt with a total capacity of 7.5 tons per day (t/d). The research methodology is applied to the design of a biodiesel production plant with a fish waste oil capacity of 547.5 tons/year. The production process involves a transesterification reaction using methanol and NaOH as catalysts. The annual expected yields are 495.2 tons of biodiesel and 51.4 tons of glycerol. The base design indicates total heating and cooling energies of 6889.6 kW and 11,470.1 kW, respectively, and CO₂ emissions of 19,343 tons/year. An improved design using Pinch Analysis achieves substantial energy savings of 47% in heating, 69% in cooling, and, 9202 tons of CO₂ cut. The novelty of the work lies in developing and applying an integrated process design and energy minimization methodology. The work provides a transferable methodology that can be applied to other wastes. Full article

This paper presents a novel, minimalist floating memristor emulator circuit designed for low-power biomedical analog front ends. The proposed topology requires only two dynamic threshold MOS (DTMOS) transistors and one capacitor, constituting one of the most compact memristor emulators reported. The circuit operates without static power consumption and exploits the body-effect coupling in DTMOS devices to generate a state-dependent resistance. Comprehensive simulation in a 0.18 μm CMOS process verifies core memristive characteristics: a frequency-dependent pinched hysteresis loop tunable via capacitance, non-volatile memory, and robustness across temperature and process variations. Experimental validation using a discrete CD4007-based prototype confirms the pinched hysteresis loop from 100 Hz to 800 kHz, with a maximum simulated operating frequency of 500 MHz. A comparative analysis demonstrates that the design achieves a favorable trade-off, simultaneously minimizing transistor count and power while providing floating operation and high-speed performance. These attributes make the emulator a compelling candidate for integration into adaptive, area and power constrained biomedical signal conditioning systems. Full article

The conversion of plastic waste into hydrogen offers a promising waste-to-value pathway, but its industrial viability is constrained by high external energy demand associated with thermochemical processing. This study evaluates the energy performance of hydrogen production from mixed plastic waste via pyrolysis and in-line steam reforming, with a focus on reducing utility consumption through systematic heat integration. A steady-state process model was developed in Aspen Plus for a representative mixture of polyethylene, polypropylene, and polystyrene, followed by detailed energy analysis and pinch-based heat integration using Aspen Energy Analyser. Baseline utility requirements were quantified and compared against optimised configurations incorporating targeted heat exchanger network modifications. The base-case analysis identified significant recoverable heat, enabling a reduction in total external utilities from 7.14 to 2.88 GJ h⁻¹, corresponding to a 59.6% decrease in utility demand. Sequential heat integration scenarios further reduced heating and cooling duties while maintaining process operability, demonstrating the effectiveness of iterative, pinch-guided design. The results show that high-temperature waste-plastic-to-hydrogen systems need not be utility-dominated when energy integration is embedded at the design stage. These findings highlight heat integration as a critical enabler for improving the energy efficiency and sustainability of pyrolysis–reforming routes and provide a robust framework for developing scalable, low-carbon hydrogen production from plastic waste. Full article

This paper presents a compact floating memtranstor (MT) emulator, a memory element characterized by a direct φ–q relationship, realized without analog multipliers or complex circuitry. The proposed design employs only two active blocks—a voltage differential transconductance amplifier (VDTA) and a voltage differential current conveyor (VDCC)—along with three grounded capacitors and a single grounded electronically tunable resistor. The emulator accurately reproduces the fundamental φ–q dynamics, exhibiting origin-crossing pinched hysteresis loops under sinusoidal excitation, and operates at a low supply voltage of ±0.9 V. Electronic tunability is achieved via bias-controlled transconductance modulation, enabling flexible adaptation across excitation frequencies and operating conditions. Validation is performed through analytical modeling, Monte Carlo simulations, temperature sensitivity analysis, and full LTspice post-layout simulations using a 180 nm CMOS process. The full-custom layout occupies 2529.49 μm², with robust performance confirmed under parasitic and process variations. Adaptive learning simulations demonstrate the emulator’s artificial synaptic plasticity, highlighting its suitability for neuromorphic computing, chaos-based circuits, and nonlinear dynamical systems. The compact, low-power, and multiplier-free architecture establishes the proposed MT emulator as a practical platform for emerging analog memory-centric applications. To validate the feasibility of the proposed solution, experimental tests are performed using commercially available components. Full article

Carbon sinks have been widely recognized as critical components of climate change mitigation and achieving carbon neutrality. With rapid urbanization, protecting and optimizing urban carbon sinks remain major challenges. This study uses Zhengzhou as a case study and analyzes 2000–2023 land-use data with the InVEST model to quantify carbon stocks and identify high-value carbon-sink areas. Circuit theory was further integrated to delineate ecological security patterns and inform optimization strategies. The results show a net decrease of 19.12 × 10⁶ t in carbon storage from 2000 to 2023, with the most rapid decline occurring during 2015–2020. Spatially, high-value carbon storage clustered in forested, high-elevation areas in the southwest, whereas low values predominated in the urban core. Carbon-sink source areas continued to shrink: fragmentation increased in the east, the west remained relatively stable, and the central area was highly fragmented. Corridor analysis indicated that the mean corridor length first increased and then decreased, accompanied by an expansion of pinch points and barrier areas. The study developed a systematic optimization framework that establishes a “Two Cores, Five Carbon-Sink Areas, Multiple Corridors” security pattern and proposes targeted conservation measures. The proposed methodology and findings offer a transferable basis for managing urban carbon sinks in rapidly developing regions and support both ecological security and climate-change mitigation, promoting sustainable urban development. Full article

Background/Objectives: The impact of stroke on upper extremity function in the older adult population underscores the need for accurate recovery prediction. Motor evoked potential (MEP) has been explored as a predictor of upper extremity function recovery in patients with stroke. However, research specifically targeting the geriatric population remains limited. Therefore, this study focused specifically on patients aged 65 years and older to investigate correlations between MEP parameters and upper extremity function. This study investigates correlations between MEP parameters (amplitude and latency) and upper extremity function-related measures, including Medical Research Council (MRC) scale, the Korean version of the Modified Barthel Index (K-MBI), and the Hand Function Test (HFT), including grip strength, pinch strength, the Box and Block Test, and the 9-Hole Peg Test, in older adults with stroke. Methods: A multiple linear regression model predicts upper extremity outcomes using initial MEP parameters, time, and function. The dataset includes 90 patients with stroke categorized by timing of the first MEP assessment: ≤3 months (n = 42) or >3 months (n = 48). Results: MEP amplitude and latency were significantly correlated with upper extremity function in both groups. No significant correlations were found between MEP amplitude or latency and outcome measures. Regression analysis showed that initial MEP amplitude had a limited association with outcomes, whereas latency was significantly associated with grip strength (β: −10.205, 95% CI: −19.374~−1.036) and the Box and Block Test (β: −10.204, 95% CI: −20.254~−0.154). Initial upper extremity parameters were significantly associated with K-MBI and HFT follow-up results (p < 0.05). Conclusions: Larger MEP amplitude and faster initial MEP latency were associated with improved upper extremity function in patients with stroke. In older patients, MEP latency, rather than amplitude, demonstrated greater predictive value for upper extremity function recovery, possibly due to age-related muscle atrophy, a factor not fully addressed in existing prognostic frameworks such as PREP2. These findings support the integration of MEP latency assessment into geriatric stroke prognostication, complementing existing frameworks such as PREP2, and may guide personalized rehabilitation planning to optimize functional recovery and independence. Full article

Rapid urban expansion across southwestern Florida has led to extensive habitat fragmentation and degradation, presenting significant ecological challenges for the persistence of multiple species, including the Big Cypress fox squirrel (Sciurus niger avicennia; BCFS), a state threatened and imperiled subspecies endemic to the Big Cypress Basin. This study uses high-resolution ecological modeling, Omniscape, to assess the functional connectivity of BCFS habitat within the urbanizing landscape of Fort Myers, Florida, and a green infrastructure (GI) transect-based approach to identify strategies for improving habitat and connectivity within the urban landscape. Results demonstrate that BCFS movement is disproportionately represented in high-density urban zones, with priority bottleneck patterns emerging in surrounding lower-density, transitional land use areas such as suburban neighborhoods and golf courses. By combining spatial modeling and applied GI design, this study offers a replicable framework for embedding species conservation into local and regional planning processes. Given the model-based and species-specific scope of this study, future research should focus on empirical validation and extending this framework across multiple species and scales. Overall, the findings emphasize the importance of multiscalar, landscape-sensitive planning strategies to mitigate anthropogenic fragmentation, enhance ecological resilience, and support the long-term persistence of native species in rapidly developing regions. Full article

The scientific establishment of ecological security pattern and identification of ecological restoration priority areas are key for territorial space ecological restoration and people’s well-being enhancement. Although numerous studies have addressed this topic, most focused on regional and urban scales. As the most basic administrative units in China, townships serve as a crucial link between macro-ecological protection strategies and micro-ecological restoration practices and are essential for effectively implementing ecological restoration and supporting rural revitalization practices, but research at this scale is currently lacking. Therefore, taking a typical township in Shanghai as an example, this study incorporated the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, Morphological Spatial Pattern Analysis (MSPA), landscape connectivity analysis, and circuit theory to construct an ecological security pattern and identify ecological restoration priority areas at the township scale, as well as to discuss corresponding ecological restoration strategies. The results showed that: (1) The study area contained 19 significant ecological sources (area of approximately 4.85 km²), exhibiting a spatial pattern characterized by “north–south concentration, central dispersion”. High-resistance areas were mainly distributed in areas with dense human activity and high development intensity, reflecting the significant impact of human activities on ecological processes. There were 32 main ecological corridors with a total length of 58.06 km, showing significant spatial imbalance, with some northern ecological sources at the risk of forming ecological isolated islands. (2) The ecological restoration priority areas mainly consisted of 41 ecological pinch points (area of approximately 27.24 ha) and 30 ecological barrier points (area of approximately 25.67 ha), which were crucial for enhancing ecological network connectivity and maintaining ecological security. (3) Based on the current land use status and spatial distribution characteristics of key ecological restoration areas, a hierarchical and categorized ecological restoration strategy was formulated. This study can strengthen research on identifying ecological restoration priority areas at the township scale. The methodological system established can provide a theoretical framework for ecological restoration research in similar areas. Moreover, this study pinpointed key areas and the spatial layout for ecological restoration, which helped to enhance the level of refined ecological governance at the township level and can also provide precise spatial decision-making basis for ecological restoration of the township territorial space. Full article

Background: Thumb carpometacarpal (CMC) arthritis affects up to 25% of women and 8% of men over 70 years of age, significantly compromising their activities of daily living. With the rapid growth of the elderly population globally and their specific clinical needs, understanding optimal surgical treatment for this age group is crucial. This systematic review compares trapeziectomy with ligament reconstruction and tendon interposition (LRTI) versus dual-mobility prosthesis for treating thumb CMC arthritis in elderly patients over 70 years old. Methods: A systematic search was conducted across PubMed, Scopus, Web of Science, and the Cochrane Library for studies published up to August 2025. Studies that directly compared both techniques were included, with subgroup analyses performed for elderly patients over 70 years of age when data were available. Primary outcomes included pain relief, functional improvement, grip and pinch strength, complications, and patient satisfaction. Results: Five studies met the inclusion criteria for direct comparison of both techniques, encompassing 313 patients (324 thumbs). While none exclusively focused on patients over 70, elderly patients represented 25–41% of study populations. Due to the absence of age-stratified data in the original studies, our analysis encompasses all age groups with specific considerations for elderly patients where identifiable. Dual-mobility prostheses demonstrated faster pain relief and earlier functional improvement, particularly within the first 3–6 months postoperatively. Prostheses consistently provided superior grip and pinch strength outcomes throughout follow-up periods. Both procedures effectively preserved thumb function, but prostheses better maintained thumb length and metacarpophalangeal stability. While complication rates were comparable, LRTI complications were typically minor and self-limiting, whereas prosthesis complications, though rare, could potentially require revision surgery. Longer-term follow-up data (>3 years) remain limited, particularly regarding implant degradation and adverse local tissue reactions. Conclusions: Both procedures effectively treat thumb CMC arthritis in elderly patients, with distinct advantages. Dual-mobility prostheses offer faster recovery, enhanced strength, and better thumb length preservation, making them potentially advantageous for elderly patients prioritizing rapid functional recovery. Trapeziectomy with LRTI provides reliable long-term pain relief with fewer serious complications, making it suitable for patients with poor bone quality or significant comorbidities. Treatment selection should be individualized based on patient characteristics, functional demands, and surgeon expertise. Future research specifically focusing on elderly populations with longer follow-up periods (>5 years) is critically needed to provide stronger evidence for this growing demographic and to better understand long-term implant performance. Full article

Continuous growth in prices for primary energy sources and environmental restrictions on pollutant emissions justify investments in industrial facilities to minimize specific energy consumption. In addition, oil-producing and refining enterprises were built in previous decades, when energy efficiency problems were not so urgent, so little attention was paid to the development and application of tools for improvement. In this regard, at present, the application and development of methods for increasing energy efficiency is certainly relevant, especially for oil processing and stabilization units (OPSUs) at fields, through which all oil produced in a country passes. Our goal is to achieve heat integration of OPSUs with a capacity of 4 million tons of processed raw materials per year. In this study, for the heat integration of the OPSU, pinch-analysis methods with the construction of grid diagrams are used for a retrofitting project for increasing the energy efficiency of the heat exchange network (HEN) of an OPSU. The heat and economic analysis of the synthesized HEN were performed using Pinch 2.02 software. This paper presents a retrofitting-based energy-efficiency project for the OPSU HEN. A method for evolving the synthesized HEN by breaking heat load paths is applied to increase the economic efficiency of the retrofit project. The stability of the OPSU operation in the optimal mode is shown with the observed change in the bank interest rate. The implementation of the synthesized HEN will reduce specific energy consumption by 77%, decreasing CO₂ emissions released into the atmosphere by 30 thousand tons per year. Full article

Channel length modulation (CLM) in indium gallium zinc oxide (IGZO) thin film transistors (TFTs) reduces the output resistance (r_o) in the saturation regime. It also degrades current driving accuracy for active matrix organic light emitting diode (AMOLED) backplanes. For top gate, self-aligned devices with nominal channel lengths of 5–15 μm, transmission line method (TLM) analysis yields an effective channel length reduction (ΔL) of about 1.8 μm. This result is consistent with lateral hydrogen redistribution from the self-aligned source/drain (S/D) process. At L = 5 μm, the conventional TFT exhibits r_o = 13.5 ± 2.5 MΩ and an Early voltage (V_A) = 56.1 ± 10.4 V (n = 5). We propose a source connected bottom gate (SCBG) structure that electrostatically stabilizes the pinch-off region and suppresses CLM. The SCBG TFT increases r_o to 475 ± 52 MΩ and V_A to 1159 ± 173 V at L = 5 μm (n = 5), while maintaining normal transfer characteristics. Two-dimensional device simulations reproduce the trend and show that the drain-bias-induced pinch-off shift is reduced, with d(ΔL)/dV_DS decreasing from 0.027 to 0.012 μm/V (about 55%). These results indicate that the SCBG approach is effective for enhancing current saturation in short channel IGZO TFTs for high-resolution AMOLED applications. Full article

Supercritical carbon dioxide (SC-CO₂) power cycles offer a promising solution for offshore platforms’ gas turbine waste heat recovery due to their compact design and high thermal efficiency. This study proposes a novel parallel-preheating recuperated Brayton cycle (PBC) using SC-CO₂ for waste heat recovery on offshore gas turbines. An integrated energy, exergy, and economic (3E) model was developed and showed good predictive accuracy (deviations < 3%). The comparative analysis indicates that the PBC significantly outperforms the simple recuperated Brayton cycle (SBC). Under 100% load conditions, the PBC achieves a net power output of 4.55 MW, while the SBC reaches 3.28 MW, representing a power output increase of approximately 27.9%. In terms of thermal efficiency, the PBC reaches 36.7%, compared to 21.5% for the SBC, marking an improvement of about 41.4%. Additionally, the electricity generation cost of the PBC is 0.391 CNY/kWh, whereas that of the SBC is 0.43 CNY/kWh, corresponding to a cost reduction of approximately 21.23%. Even at 30% gas turbine load, the PBC maintains high thermoelectric and exergy efficiencies of 30.54% and 35.43%, respectively, despite a 50.8% reduction in net power from full load. The results demonstrate that the integrated preheater effectively recovers residual flue gas heat, enhancing overall performance. To meet the spatial constraints of offshore platforms, we maintained a pinch-point temperature difference of approximately 20 K in both the preheater and heater by adjusting the flow split ratio. This approach ensures a compact system layout while balancing cycle thermal efficiency with economic viability. This study offers valuable insights into the PBC’s variable-load performance and provides theoretical guidance for its practical optimization in engineering applications. Full article

Against the backdrop of rapid urbanization and land development, the degradation of regional ecosystem services and the intensification of ecological risks have become prominent challenges. This study takes the Pinglu Canal Economic Belt—a region characterized by the triple pressures of “large-scale engineering disturbance, karst ecological vulnerability, and port economic agglomeration”—as a case study. Based on remote sensing image data from 2000 to 2020, a landscape ecological risk index was constructed, and regional landscape ecological risk levels were assessed using ArcGIS spatial analysis tools. On this basis, ecological sources were identified by combining the InVEST model with morphological spatial pattern analysis (MSPA),and an ecological resistance surface was constructed by integrating factors such as land use type, elevation, slope, distance to roads, distance to water bodies, and NDVI. Furthermore, the circuit theory method was applied to identify ecological corridors, ecological pinch points, and barrier points, ultimately constructing the ecological security pattern of the Pinglu Canal Economic Belt. The main findings are as follows: (1) Ecological risks were primarily at low to medium levels, with high-risk areas concentrated in the southern coastal region. Over the past two decades, an overall optimization trend was observed, shifting from high risk to lower risk levels. (2) A total of 15 ecological sources (total area 1313.71 km²), 31 ecological corridors (total length 1632.42 km), 39 ecological pinch points, and 15 ecological barrier points were identified, clarifying the key spatial components of the ecological network. (3) Based on spatial analysis results, a zoning governance plan encompassing “ecological protected areas, improvement areas, restoration areas, and critical areas” along with targeted strategies was proposed, providing a scientific basis for ecological risk management and pattern optimization in the Pinglu Canal Economic Belt. Full article

Crude distillation units operate as the most energy-intensive refinery operations and generate substantial carbon dioxide emissions. This research models the crude distillation system through its three main components: the atmospheric distillation unit, the naphtha stabilisation unit, and the vacuum distillation unit. The simulation platform Aspen HYSYS version 14.1 enabled optimisation of the preflash drum under product quality constraints, and the analysis included pinch analysis techniques and techno-economic evaluation. The optimisation results demonstrated an 8.95% reduction in atmospheric furnace duty, a 7.38% decrease in total hot utility consumption with the crude distillation system, and an increase in heat recovery capability from 35.57% to 42.71%. Although the preflash process alone decreases profitability because of increased steam demand, combining preflash operation with heat recovery measures maintains both energy conservation and favourable economic performance. The study shows that refinery optimisation requires treating the crude distillation system as a fully integrated process. This approach offers effective strategies to improve energy performance and reduce carbon dioxide emissions while sustaining economic viability. The work differs from previous studies by evaluating the entire distillation system as an integrated sequence and demonstrating how preflash optimisation affects overall energy demand, heat-recovery potential, and economic outcomes while maintaining product quality. Full article