Resistance Model Research Articles

Effect of tissue viscoelasticity on delivered mechanical power in a physical respiratory system model: distinguishing between airway and tissue resistance

Understanding the mechanics of the respiratory system is crucial for optimizing ventilator settings and ensuring patient safety. While simple models of the respiratory system typically consider only flow resistance and lung compliance, lung tissue resistance is usually neglected. This study investigated the effect of lung tissue viscoelasticity on delivered mechanical power in a physical model of the respiratory system and the possibility of distinguishing tissue resistance from airway resistance using proximal pressure measured at the airway opening. Three different configurations of a passive physical model of the respiratory system representing different mechanical properties (Tissue resistance model, Airway resistance model, and No-resistance model) were tested. The same volume-controlled ventilation and parameters were set for each configuration, with only the inspiratory flow rates being adjusted. Pressure and flow were measured with a Datex-Ohmeda S/5 vital signs monitor (Datex-Ohmeda, Madison, WI, USA). Tissue resistance was intentionally tuned so that peak pressures and delivered mechanical energy measured at airway opening were similar in Tissue and Airway Resistance models. However, measurements inside the artificial lung revealed significant differences, with Tissue resistance model yielding up to 20% higher values for delivered mechanical energy. The results indicate the need to revise current methods of calculating mechanical power delivery, which do not distinguish between tissue resistance and airway flow resistance, making it difficult to evaluate and interpret the significance of mechanical power delivery in terms of lung ventilation protectivity.

A Calculation Model of Cutterhead Resistance for Pipe Jacking in Rock Strata and Soil–Rock Composite Strata

ABSTRACTJacking force is one of the most important parameters in the design and construction of pipe jacking engineering, and cutterhead resistance is an important part of jacking force. Pipe jacking is increasingly applied to rock strata, but there are few calculation models for the jacking force in rock strata and soil–rock strata. For this reason, this article, under the assumption of stable conditions of pipe jacking face, summarizes the cutterhead resistance of soil strata. The rock‐breaking mechanism, stress model, and influence law of cutterhead of rock pipe jacking machine are analyzed. And on this basis, the calculation formula of cutterhead resistance of pipe jacking in rock strata is deduced. And the cutterhead resistance of soil–rock composite strata is determined according to the proportion of strata. Finally, the field measured values and code calculation results are compared with the formula values in this article. The results show: in rock pipe jacking, the compressive and shear strengths of the rock and the depth of the pipe jacking cutter cut into the rock directly determine the value of the cutterhead resistance; and the calculated value of cutterhead resistance of soil–rock composite strata determined according to the strata ratio is consistent with the measured cutterhead resistance, which proves its applicability.

Investigating the Acceptability of an Interactive Television Intervention Promoting Social Links Among Older Adults Living at Home and in Care Institutions: Qualitative Interview and Questionnaire Study

Background When older adults (OAs) can no longer live independently at home, they have the option to choose from various types of geriatric care institutions, such as residential facilities or nursing homes. For several years now, thanks to the development of interactive television (iTV), social link functions have been accessible directly on televisions, tools that are already integrated into residents’ rooms. The acceptance of technologies specifically targeting older users, as well as iTV, has been widely documented in the literature, incorporating factors from the innovation resistance model. Objective This research aims to enrich the acceptance of existing models of innovation by OAs living in different settings. Methods User tests were carried out to evaluate OAs’ experiences with iTV and identify the factors involved in its acceptance. A total of 32 OAs living at home, in nursing homes, or in residential facilities in France were interviewed between November 2022 and June 2023. iTV acceptance was examined using an interview grid based on the technology acceptance model and included the following factors: intention to use, perceived usefulness, perceived ease of use, user resistance, anxiety, facilitating conditions, and user characteristics. Results The deductive qualitative analysis based on the technology acceptance model helped to identify 33 concepts. Conclusions This study has contributed to the literature on the acceptance of iTV by OAs living at home and in geriatric institutions, particularly by enriching existing models and proposing new avenues for reflection.

Effects of Different Spatial Distributions of Vegetation on the Hydraulic Characteristics of Overland Flow

ABSTRACTVegetation plays a crucial role in mitigating and controlling soil erosion caused by overland flow. However, variations in the hydraulic characteristics of overland flow induced by the spatial distribution of vegetation with different row and column spacings are often overlooked in existing literature, potentially leading to significant deviations in predicting these characteristics. In this study, 180 lab‐scale runoff tests were conducted to clarify the hydraulic characteristics of overland flow considering six α (the ratio of the lateral distance of vegetation to stem diameter) levels, six β (the ratio of the slope distance of vegetation to stem diameter) levels, and three slope angles (θ) under five flow discharges (Q) conditions. The results show that the observed flow regime of overland flow belongs to the transition flow regions, shifting from slow to rapid as α and/or β increase. The friction coefficient and the proportion of frictional resistance in the total flow resistance increase with increasing α and β. The local resistance dominates the total flow resistance of bare glass slopes. The local resistance coefficient ξ decreases with increasing α and β, however, it initially increases and then decreases with increasing θ. The impact of β on the local resistance is greater for gentle slopes, whereas the impact of α is more significant for steep slopes. ξ exhibits a negative correlation with Re and the ξ‐Re curves gradually level off as α or β increases, while they become steeper with increasing θ. A prediction model for the total flow resistance was established taking into account the combined effects of Re, α, β and θ, which provides better prediction performance than two other relevant models. The results obtained from this study provide valuable insights into the hydraulic characteristics of overland flow and offer clear guidance for vegetation management in controlling soil erosion on slopes with heterogeneous vegetation coverage.

The emergence of nonlinear evolutionary trade-offs and the maintenance of genetic polymorphisms.

Evolutionary models of quantitative traits often assume trade-offs between beneficial and detrimental traits, requiring modellers to specify a function linking trait values. The choice of trade-off function can be consequential; functions that assume diminishing returns (accelerating costs) typically lead to single equilibrium genotypes, while decelerating costs often lead to genetic polymorphisms. Despite their importance, our current theory has little to say on which trade-off functions are the most biologically plausible. To address this gap, we explored how the genetic determination of quantitative traits can lead to different trade-off functions, using resistance to infectious diseases as an example trait. We developed a model where alleles at separate loci pleiotropically increase resistance while decreasing fecundity. We then used this model to generate genotype landscapes and investigate how epistasis effects the trade-off function. Regardless of the strength of epistasis, our model consistently led to accelerating costs. We then incorporated our genotype model into an eco-evolutionary model of disease resistance. Unlike other models with accelerating costs, our approach often led to genetic polymorphisms. Our results suggest that accelerating costs are a strong null model for evolutionary trade-offs and that the eco-evolutionary conditions required for polymorphism may be more nuanced than previously thought.

Constructing ecological network based on multi-objective genetic algorithms: a case study of Changsha City, China

ContextRegional ecological security faces serious threats in a changing world. Ecological network (EN) provides decision-makers with spatial strategies for maintaining ecological security and landscape sustainability via alleviating the contradiction between ecological conservation and economic growth. Despite years of intense and fruitful studies, accurately identifying ecological source patches when facing multiple conflicting objectives still remains a challenge.ObjectivesThis study aimed to propose an advanced framework for recognizing ecological source patches with consideration of multiple objectives and further constructing EN, which would promote a more profound understanding of local ecological condition and provide spatial guidance for ecological conservation planning.MethodsTaking Changsha City as the study area, we evaluated the ecological condition by considering three key ecosystem services, i.e., habitat maintenance, carbon sequestration and water yield using the InVEST model. Ecological source patches were identified using multi-objective genetic algorithms (MOGA) in view of ecosystem services, landscape connectivity and the total area of ecological source patches. Ecological corridors were extracted by applying Minimum Cumulative Resistance (MCR) model based on modified ecological resistance surface. The EN was established by combining these ecological source patches with ecological corridors.ResultsThe EN in Changsha City was comprised of 51 ecological source patches and 50 ecological corridors. The ecological source patches were primarily distributed across the eastern and western mountainous areas with the total area of 2842 km2, occupying 24.05% of the study area. There was a clear lack of ecological source patches along the Xiangjiang River owing to the high level of urbanization, which deserved particular attention for ecological restoration. Overall, the identified ecological source patches provided 87.31% of ecosystem service supply and 82.49% of the whole landscape connectivity by occupying 67.09% of the dominant patch area. The depicted ecological corridors formed two clusters in the central and northeastern parts of the study area.ConclusionsThis study offered new insights into accurately identifying ecological source patches by coordinating various conservation objectives. With the application of MOGA, the proposed framework consolidated ecosystem services, landscape connectivity and patch area to effectively delineate core ecological patches.

Construction and Evaluation of Urban Green Infrastructure in Ecologically Vulnerable Areas Based on Multi-Scale and Multi-Objective Approaches: Taking the Four-Lake Hydrographic Network in the Upper Yellow River Basin as an Example

The construction and optimization of urban green infrastructure (UGI) are regarded as effective strategies for harmonizing the natural landscape with human activities, particularly in ecologically vulnerable areas in the Upper Yellow River Basin, China. However, there is little attention paid to the scale effects and object effects as well as an absence of comprehensive assessments regarding landscape stability. Taking the Four-Lake Hydrographic Network (FLHN) in Shizuishan, a prefecture-level city, as an example, this study focuses on identifying the important sources of UGI by integrating both regional and interregional perspectives utilizing morphological spatial pattern analysis (MSPA). UGI networks were constructed and optimized based on trade-offs and synergizing relationships between individual objects using the minimum cumulative resistance (MCR) model, and the UGI network’s stability combined centrality and connectivity aspects, which were subsequently assessed. The results showed that a total of 19 important sources covering an area of 105.07 km2 were identified in the FLHN, integrating both regional and interregional levels. It was deemed unnecessary to maintain lengths of 7.79 km key corridors, 9.42 km general corridors, and 29.89 km fragile corridors; furthermore, there was no longer a requirement to upgrade an additional 5.51 km of general corridors and 25.78 km of any corridor, as UGI corridors were extracted based on a trade-off and synthesized objective methodology. The overall connectivity index value (OG) of UGI stability with respect to the multi-objective model demonstrated superior performance compared to the same index in scenarios involving the use of a single-objective approach and the straightforward overlay of each object. This study reveals the multifaceted requirements of urban landscape security and sustainability, indicating that multi-scale and multi-objective approaches in territorial space planning not only ensure the integrity of the landscape patterns but also reduce the costs associated with landscape construction. This model can be utilized to implement urban landscape entity protection and restoration for landscapes with various geographical characteristics, and it can provide valuable guidance for similar areas.

On the design and behavior of axially-compressed square concrete-filled double-skin tubular short columns for ocean engineering applications

Deep-sea offshore wind technology development is now deemed a strategic national need in China. At the same time, research and engineering communities have a substantial increase in intertest on the design and behavior of novel arrangements for double-skin composite columns. Accordingly, concrete-filled double-skin steel tubular (CFDST) columns have recently gained significant importance in wind farm support structures as well as tall buildings with heavy loads. To predict the axial compressive resistance of square CFDST short columns with square inner tubes (SS-CFDST) or circular inner tubes (SC-CFDST), a new design resistance model has been proposed in this paper. First, test data for axially-loaded short columns of SS-CFDST and SC-CFDST configurations were extracted from literature studies. Then, available design resistances in the European and American specifications, as well as from previous studies, were examined, and a range of accuracy results were displayed. Subsequently, new formulae for determining the lateral confining pressure (frp) supplied by outer and inner tubes in different types of square CFDST columns have been developed using the data gathered from the experimental tests. A new design resistance model has then been proposed to calculate the axial compressive resistance of SS-CFDST and SC-CFDST short columns, based on the proposed formulae for frp in addition to the confined concrete strength. This has been followed by a finite element (FE) modeling using ABAQUS program that has been well validated, generated to increase the resistance data of these columns. The design formula was then verified through the extensive parametric studies generated by the FE modeling. According to the comparisons between numerical and proposed resistances, the design proposal was found to yield more accurate and reliable results in terms of the average resistance ratio, accuracy across the whole range of the relative tube slenderness ratio and the calculated reliability index.

Design model for shear keys used as thermal break systems in balcony-slab joints under combined shear and bending loads

Balcony-slab joints (BSs) are common in residential buildings. Integrating thermal break systems (TBSs) can reduce the energy loss resulting from thermal bridging. However, the mechanical performance of BSs equipped with TBSs against shear and bending remains hardly explored in design and experimentation. The aim of this study is to evaluate the mechanical behavior of BS joints under combined shear and bending actions, taking into account the presence of TBSs. Seven large-scale balcony-slab specimens were fabricated and tested under vertical loading with different moment-shear ratios (M/V). The BSs are equipped with TBSs comprising steel bars and shear profiles. A simplified finite element (FE) model was then developed using the ABAQUS software. The FE model employs spring-like elements to simulate the bond and contact behavior between concrete and steel, reproducing both the resistance and stiffness of the tested specimens. On the basis of the experimental and FE results, a resistance model consistent with the Eurocode design guidelines was drawn. Finally, moment-shear (M-V) interaction curves for balcony-slab joints were generated at the ultimate (ULS) and serviceability (SLS) levels, considering the impact of horizontal loading to achieve comprehensive design insights. The tests and FE results showed that the moment-shear ratio (M/V) significantly influences the shear capacity of the BS joints. The steel profiles effectively acted as shear keys connecting the balcony and the slab. A strength reduction coefficient of 0.701 was introduced for the design.

Research on Modified Thermal Barrier Coatings Against CMAS Corrosion Driven by Mechanism–Data Hybrid Model

With the development of high-efficiency gas turbine engines and increasing inlet temperatures, the performance of thermal barrier coatings (TBCs) for hot-section components has been more severely challenged. The doping of multi-element rare earth elements significantly improves the thermodynamic properties and chemical compatibility of thermal barrier coatings so that the application performance of coatings in high-temperature environments is enhanced considerably. In this work, the doped coatings prepared by REYSZ (RE = La, Sm, Nd) were investigated and characterized in terms of crystal structure, elastic properties, and thermal–mechanical properties based on the first-principles approach, combined with various empirical and semi-empirical formulations, and a predictive model for resistance to CMAS corrosion based on machine learning approaches. The results showed that the tetragonal phase REYSZ material was mechanically stable, had a large strain damage tolerance, and was not easy to fracture under applied loads and thermal shocks. In terms of CMAS corrosion resistance, the NdYSZ interfacial model had a lower surface energy (3.130 J/m2) and Griffith fracture energy (6.934 J/m2) compared with the conventional YSZ model, and Nd2O3 had the potential to improve the CMAS corrosion resistance of zirconia-based material for thermal barrier coatings. By evaluating the machine learning prediction models, the regression coefficients of the two algorithms were 0.9627 and 0.9740, and both these two prediction models showed high prediction accuracy and strong robustness. Ultimately, this work presented a novel mechanism–data hybrid method, which would facilitate the efficient development of TBC new materials for anti-CMAS corrosion.

Coupled Effects of Time and Temperature on the Rheological and Pipe Flow Properties of Cemented Paste Backfill

As mineral resources at shallow depths become increasingly depleted, the development of these resources is progressively shifting to greater depths. This transition presents challenges for the pipeline transport of cement paste backfill (CPB), particularly in terms of long-distance transport and elevated temperatures. To investigate this phenomenon, we conducted rheological tests, developed a resistance model that accounts for both time and temperature, and performed numerical simulations. The results show that the rheological parameters of CPB exhibit a gradual decline as the flow progresses. Specifically, at 20 °C, the plastic viscosity of CPB decreases by 1.6 Pa·s, and the yield stress decreases by 48.15 Pa; at 30 °C, the plastic viscosity decreases by 1.3 Pa·s, and the yield stress decreases by 18.69 Pa; at 40 °C, the plastic viscosity decreases by 0.84 Pa·s, and the yield stress decreases by 12.55 Pa; and at 50 °C, the plastic viscosity decreases by 0.58 Pa·s, with the yield stress decreasing by 12.53 Pa. Furthermore, the influence of shear time on the rheological properties of CPB diminishes as temperature increases within the range of 20 °C to 50 °C. These results offer significant insights for optimizing the pipeline transport of CPB in mining operations. These findings provide valuable guidance for pipeline transport of CPB in mining operations.

Insight into the effect of Tubificidae on dynamic membrane reactor: Membrane fouling mitigation and Tubificidae-ASM3-dynamic membrane coupled model

To gain insights into the effects of Tubificidae on dynamic membrane sequencing batch reactor (DMSBR), 4 identical DMSBRs were operated with different Tubificidae densities (i.e., 0, 1, 2, 3 g ww/L). Experimental results showed that Tubificidae had a minimal effect on carbon and nitrogen removal but varied effluent turbidity and sludge characteristics. An appropriate density (2 g ww/L) of Tubificidae significantly decreased effluent turbidity and mitigated membrane fouling, which was attributed to the minimized mixed liquor suspended solids (MLSS) and the maximized particle size. A Tubificidae-ASM3-dynamic membrane coupled model was developed by combining the biological model with the dynamic membrane resistance model, incorporating the extracellular polymeric substances (EPS) to characterize its contribution to membrane pore fouling, and introducing an inhibitory function to limit the unrestricted growth of membrane resistance. The model can be considered as a first attempt to describe the observed Tubificidae effects on dynamic membrane reactor.

Flavonoids from Ougan (Citrus suavissima Hort. ex Tanaka) peel exert hypoglycemic potency through inhibiting insulin resistance in HepG2 cells and regulating gut microbiota in diabetic mice

To fully and value-addedly utilize the citrus peel resource, flavonoids were extracted and purified from peel powder of Ougan (Citrus suavissima Hort. ex Tanaka) using an ultrasonic assisted ethanol solution extraction method and AB-8 macroporous resin purification. The obtained flavonoid extract from peel of Ougan (FEPO) was used for the hypoglycemic experiments in vitro and in vivo on glucose consumption in insulin resistance model HepG2 cells and streptozotocin induced diabetes model mice. A significant reduction of glucose consumption in the model cells while a significant increase in the treated were found in a dose-dependent manner, compared to 5.2241 ± 0.2201 mmol/L of the normal cells (P < 0.05). When the FEPO concentration was 80 μg/mL, the cell glucose consumption was 4.4055 ± 0.1772 mmol/L. Compared with those in the model group (diabetic mice), the fasting blood glucose in the FEPO intervened mice was significantly decreased (P < 0.05). FEPO intervention caused decreased levels of TC, TG, LDL-C, and increased HDL-C and insulin contents in the serums as well as ameliorative histopathology of the liver, kidney, and pancreas in diabetic mice. FEPO improved the gut microbiota structure of diabetic mouse by regulating its composition, especially significantly increasing the relative abundance of Lactobacillus, Ileibacterium, unclassified_f_Lachnospiracea, Romboutsia, norank_f_Muribaculaceae, Faecalibaculum and Coriobacteriaceae_UCG-002 (P < 0.05), while decreasing that of norank_f_norank_o_Clostridia_UCG-014, Lachnospiraceae_NK4A136_group and Candidatus_Saccharimonas. In conclusion, FEPO had good hypoglycemic efficacies both in vitro and in vivo as well as gut microbiota regulating effect.

Prediction Model of Pipeline Push Resistance in Tunnels

The installation of pipes in tunnel construction using the external welding method requires the assistance of a pipe pusher and roller support to push the welded pipe into the tunnel. Accurate determination of pipeline push resistance and the selection of an appropriate pipe pusher model are crucial factors for successful construction. Currently, there is no effective method available for predicting push resistance, which may result in inaccurate estimation and inadequate thrust provided by the selected pipe pusher. Therefore, this study aims to establish a reliable formula for calculating push resistance through theoretical analysis and numerical simulation. Additionally, we investigate the rolling resistance coefficient between the pipe and roller wheel to develop a corresponding prediction formula. Finally, a test platform is set up to validate our proposed formula for estimating push resistance. The results demonstrate that there is approximately a 5% error between the calculated values and the test values, confirming that this method effectively predicts pipeline push resistance.

Being a Pakistani mother in Catalonia: a mixed methods study

IntroductionIn Pakistani migrant families, contextual transformation can affect adult caregivers’ parental skills and their ability to exercise positive parenting. We focused on identifying and describing patterns, practices and beliefs about parenting, identifying differential characteristics between the context of origin and the host context, and exploring Pakistani immigrants’ use of resources or assets in the area of parenting support.MethodsParticipants consisted of 20 women, established in Catalonia, Spain (&amp;lt;5 years of residence) who have children (at least one of preschool-age). We used a method of indirect observation based on verbal narrative data and textual material that allows integration between qualitative and quantitative elements. The analysis of polar coordinate (quantitative) was applied to obtain a map of interrelationships between codes/categories, based on code matrices. This method is innovative as this is the first study we know in which focus groups have been analyzed through polar coordinate.ResultsOur findings underscore the importance of examining in-depth the concept of family, parenting and upbringing from a cross-cultural perspective. Our results suggest that Pakistani migrant mothers dedicate resources and efforts to maintain the values and practices of origin, and to transmit them to the following generations.DiscussionConstant communication among relatives using new technologies, the desire to return to Pakistan, and the absence of spaces for interaction between native and migrated families facilitate the maintenance of the upbringing model of origin and resistance to change. A nuclear family structure and access to educational and health services promote acculturation processes in favor of adaptation to the new reality.

Estimating the transpiration of kiwifruit using an optimized canopy resistance model based on the synthesis of sunlit and shaded leaves

Accurate estimation of transpiration (T) in kiwifruit trees is essential for effective irrigation and water management. Canopy resistance (rc) is crucial for estimating T, but existing models do not fully consider the unique canopy structure and microclimate variations in kiwifruit trees. This study established a rc estimation model based on a synthesis of sunlit and shaded leaves (SSL) and optimized it using Ant Colony Optimization (ACO), Grey Wolf Optimizer (GWO), and Whale Optimization Algorithm (WOA). Using the rc value inverted by the Penman-Monteith model as a standard, we compared the simulation accuracy of the SSL and Jarvis models to identify the optimal model for accurate T estimation under various data availability conditions. The results indicated significant physiological differences between sunlit and shaded leaves, with shaded leaves showing lower net photosynthetic rates and higher stomatal resistance. The optimization SSL model demonstrated improved accuracy over the Jarvis model. The simulation accuracy of the SSL model optimized by the WOA algorithm was the highest, yielding R2, RRMSE, and MAE of rc and T are 0.83, 0.12, 82.55 s m−1, and 0.81, 0.09, 0.23 mm d−1, respectively. In the Jarvis model with different restriction functions the highest accuracy for rc and T, achieved after optimizing by ACO algorithm, yielded R2, RRMSE, and MAE of 0.71, 0.33, 305.94 s m−1, and 0.72, 0.23, 0.65 mm d−1, respectively. Therefore, the SSL model can more accurately estimate the rc and T, and it provides a valuable way for scientific water use and precise irrigation in kiwifruit orchards.

Donepezil improves skeletal muscle insulin resistance in obese mice via the AMPK/FGF21-mediated suppression of inflammation and ferroptosis.

Donepezil has traditionally been used in Alzheimer's disease treatment and is known for its ability to alleviate neural inflammation and apoptosis. However, its impact on insulin signaling remains unexplored. This study sought to elucidate the novel role of donepezil in mitigating skeletal muscle insulin resistance under hyperlipidemic conditions. Western blot analysis was used to assess the expression of various proteins of interest, whereas a glucose uptake assay was performed in skeletal muscle cells via commercially available kits. An in vitro model of obesity was developed using palmitate. These in vitro findings were corroborated in vivo via insulin resistance models established through high-fat diet (HFD) feeding in mice. Intraperitoneal glucose tolerance tests and insulin tolerance tests were performed on the experimental mice. The results revealed that donepezil treatment improved insulin signaling and inflammation in palmitate-treated C2C12 myocytes and the skeletal muscle of HFD-fed mice. Notably, donepezil treatment augmented FGF21 expression and AMPK phosphorylation in the myocytes and skeletal muscle of HFD-fed mice. Knockdown of FGF21 or AMPK via siRNA reversed the effects of donepezil on insulin signaling and inflammation in cultured myocytes. We also found that donepezil ameliorated skeletal muscle insulin resistance via the FGF21-mediated suppression of ferroptosis under hyperlipidemic conditions. These findings suggest that donepezil enhances the FGF21/AMPK axis, thereby mitigating inflammation and insulin resistance in skeletal muscle. This study introduces a novel therapeutic approach for treating Alzheimer's disease patients with insulin resistance.

Construction of Green Space Ecological Network in Xiongan New Area Based on the MSPA–InVEST–MCR Model

With the rapid pace of urbanization, the integrity and connectivity of ecosystems are under serious threat, making biodiversity conservation a top priority. We use the Xiongan New Area in China as a case study to explore the significance and application of constructing urban ecological networks in the development of new cities. This study systematically applied the categorization of green space systems using remote sensing technology; MSPA was used to identify key landscape patches; InVEST was employed to assess habitat quality; and potential ecological corridors were established using the minimum cumulative resistance model (MCR). Moreover, targeted recommendations for optimizing ecological green spaces were put forward. The findings demonstrate that the Xiongan New Area has significant potential and needs for ecological network construction, and it faces the issue of ecological network fragmentation. This research highlights the significance of developing ecological networks within urban planning and proposes optimization strategies tailored to these networks. The objective is to offer scientific guidance for the design and development of emerging cities, such as the Xiongan New Area, to facilitate the alignment and integration of ecological preservation efforts with urban expansion, ultimately achieving the sustainable development goal of harmonious coexistence between the environment and urban areas.

Cooling high power electronics using dynamic phase change material

Phase change materials (PCMs) offer effective transient cooling due to their high latent heat of fusion and energy density. Unfortunately, PCMs generally have relatively low thermal conductivity, impeding effective heat dissipation from the heat source and limiting their power density. This work uses dynamic PCM (dynPCM) cooling for thermal management of high power electronics. DynPCM cooling uses pressure-enhanced close-contact melting of a PCM. The applied pressure causes liquid PCM to be pumped away from the heat transfer surface, maintaining a thin melt layer and high heat transfer. Through experimental investigations with a circuit board mounted 2 × 2 array of gallium nitride (GaN) power transistors integrated with heat spreaders of different thicknesses, we evaluate the cooling performance of dynPCM across various device heat dissipation levels (4.4 W/cm² to 46.6 W/cm²) and under both homogeneous and heterogeneous heating conditions. Using paraffin as the PCM, we explore the effects of different pressures (0 Pa, 750 Pa, and 7.5 kPa) on dynPCM cooling effectiveness. DynPCM significantly enhances cooling for electronics operating at high power, achieving over a 50 % reduction in steady-state junction temperature when compared to both traditional air-cooled and hybrid PCM-cooled systems at a 32.4 W/cm² individual GaN device power loss. We developed a reduced-order thermal resistance model to assess heat transfer from the electronic devices through the heat spreader into the dynPCM. The model helps to illustrate the critical role of the heat spreader design and PCM geometry on cooling performance, offering design guidelines for dynPCM thermal management systems. This work highlights the potential of dynPCM as a thermal management strategy for high-power electronic devices, facilitating the advancement of more effective cooling methods for a variety of applications.

Optimization of ecological network to improve water conservation services in the Nianchu River Basin

Against the backdrop of water resource depletion in the Qinghai-Tibet Plateau, water conservation services (WCS) have emerged as critical ecosystem services warranting attention. Adjusting the ecological network (EN) structure and optimizing topological relationships among landscape elements are instrumental in facilitating ecological processes, constituting an effective approach for enhancing WCS. We employed the Integrated Valuation of Ecosystem Services and Tradeoffs model to simulate the WCS value in the Nianchu River Basin and used the Minimum Cumulative Resistance model in combination with the Linkage Mapper to construct an EN. Through topological analysis based on complex network theory, we examined the EN topology and identified ecological pinch points and barriers by applying circuit theory. According to the correlation between EN topology and WCS, and taking into account local vegetation restoration potential, we ultimately optimized the EN to enhance the WCS value. The results revealed a positive correlation between the WCS value and betweenness centrality (r = 0.86, p < 0.01) of forest patches, as well as with the clustering coefficient of grassland patches (r = 0.44, p < 0.05). Following the optimization of key areas with restoration potential, we enhanced the EN structure by adding six new patches, eliminating four redundant corridors, and establishing 11 new corridors. The optimized EN demonstrated enhanced stability in robustness tests, indicated by a reduced slope of edge recovery against malicious attacks (from −0.0224 to −0.0199) and an increase in the WCS value of 630,311.6 m³. This study highlights the importance of landscape spatial structure in enhancing ecosystem services, providing valuable insights for sustainable water resource management in the ecologically sensitive regions of the Qinghai-Tibet Plateau.