Area Ratio Research Articles

Paraspinal Muscle Parameters Predict Postoperative Sagittal Balance in Cervical Disc Arthroplasty: A Structural Equation Model Analysis.

Retrospective analysis. To identify the associations between preoperative paraspinal muscle parameters and postoperative outcomes following cervical disc arthroplasty (CDA), while screening for predictors. Paraspinal muscles play a critical role in maintaining cervical alignment, significantly contributing to cervical mobility and stability. To date, there is limited evidence regarding the impact of paraspinal muscles on CDA. This study included 185 patients who underwent single-level CDA. Preoperative paraspinal muscle parameters, including fatty infiltration (FI), cross-sectional area ratio (CSA r), and muscle asymmetry (ASY%), were assessed using MRI. Correlation analysis was employed for preliminary screening. Finally, structural equation modeling (SEM) was employed for comprehensive analysis. Paraspinal muscle degeneration was prevalent in this cohort, with a higher proportion of moderate to severe FI (Goutallier Grade > 2) from the cranial to caudal levels. According to the correlation analysis, at the final follow-up, cervical lordosis was most strongly correlated with CSA r at C4/5 (P=0.010); SVA was most related to CSA r at C5/6 (P=0.030); and the T1 slope was associated with CSA r at C4/5 (P<0.001), C5/6 (P<0.001), as well as at the surgical level (P<0.001). Moreover, a positive correlation was observed between preoperative pain scores and FI (P=0.035). However, no such correlation was identified in the postoperative period. Comparative analysis of SEMs across different muscle variables revealed variations in predictive factors for postoperative sagittal balance parameters, with CSA r emerging as the significant contributor (P=0.019, Estimate=0.176), rather than FI or ASY%. Compared with postoperative clinical outcomes, mobility, and prosthesis stability, preoperative muscle parameters were most correlated with sagittal balance after CDA. Specifically, CSA r outperformed in predicting postoperative sagittal balance. These findings suggest CDA may be associated with an elevated risk of sagittal imbalance when performed on patients with significant preoperative muscle degeneration. 3.

Hepatic alveolar echinococcosis infection induces a decrease in NK cell function through high expression of NKG2A in patients

Echinococcus multilocularis larval tapeworm infection in humans is considered a serious public health issue. The immune interaction between parasites and their hosts is extremely important. NK cells are known innate immune cells that play important roles during infection and tumour progression. However, the possible role of NK cells in hepatic alveolar echinococcosis is not completely clear. In this study, we investigated the functional decrease in NK cells in hepatic alveolar echinococcosis (AE) patients.MethodsUsing human liver tissue samples from 10 patients with hepatic AE, flow cytometry was used to detect the expression of NKG2A molecules on the surface of NK cells, and the correlations between NKG2A+ expression and lesion size, alkaline phosphatase (ALP) levels in close lesion tissues (CLTs) and distal lesion tissues (DLTs) in the liver, and the secretion of functional molecules by NKG2A+ NK cells were analysed.ResultsThe expression of NKG2A on CD56dim and CD56bright NK cells in DLTs and CLTs revealed that the percentage of NKG2A+CD56dim NK cells in CLTs was significantly greater than that in DLTs. There was a negative correlation between the expression of NKG2A on NK cells in the CLT and alkaline phosphatase. Additionally, we analysed IFN-γ, TNF-α, granzyme B, and perforin production in NK cells. There was a significant reduction in IFN-γ production in CLTs compared with DLTs. There is a negative correlation between IFN-γ production levels and NKG2A expression in NK cells from the CLT. The capacity of NKG2A+ NK cells from CLT regions to produce IFN-γ and granzyme B was also significantly decreased. In contrast, the perforin level produced by NKG2A+ NK cells was much greater than that produced by NKG2A− NK cells. We also analysed the correlation between the ratio of the NKG2A expression area in CLT and DLT tissues and the PET–CT value and found a positive correlation between NKG2A expression and the PET–CT value.ConclusionThe increased expression of NKG2A in NK cells induced a reduction in IFN-γ production, and the increased expression of NKG2A may improve lesion activity and fibrosis, which may be helpful for treating hepatic alveolar echinococcosis via immunity.

Multiphysics-Driven Structural Optimization of Flat-Tube Solid Oxide Electrolysis Cells to Enhance Hydrogen Production Efficiency and Thermal Stress Resistance

The solid oxide electrolysis cell (SOEC) has potential application value in water electrolysis for hydrogen production. Here, we propose an integrated multi-scale optimization framework for the SOEC, addressing critical challenges in microstructure–property correlation and thermo-mechanical reliability. By establishing quantitative relationships between fuel support layer thickness, air electrode rib coverage, and Ni-YSZ volume ratio, we reveal their nonlinear coupling effects on the hydrogen production rate and thermal stress. The results show that when the fuel support layer thickness increases, the maximum principal stress of the fuel electrode decreases, and the hydrogen production rate and diffusion flux first increase and then decrease. The performance is optimal when the fuel support layer thickness is 5.4 mm. As the rib area decreases, the hydrogen production rate and thermal stress gradually decrease, but the oxygen concentration distribution becomes more uniform when the rib area portion is 42%. When the Ni volume fraction increases, the hydrogen production rate and the maximum principal stress gradually increase, but the uniformity of H2O flow decreases. When the Ni volume fraction is lower than 50%, the uniformity of H2O flow drops to 20%. As the volume fraction of nickel (Ni) increases, the fuel utilization gradually increases. When the volume fraction of Ni is between 50% and 60%, the fuel utilization reaches the range of 60–80%. This study indicates that the fuel support layer thickness, rib area, and Ni-YSZ ratio have different effects on the overall performance of the SOEC, providing guidance for the optimization of the flat-tube SOEC structure.

Fate and speciation of NOx in an arid climatic region: factors assessment

NO and NO2 continuously recycle in the lower atmosphere through a complex series of reactions involving NO, VOCs, NO2, and O3. Therefore, the NO2/NOx ratio can be utilized in dispersion models as an important substitute to understand the fate of NO and NO2 in the atmosphere. In this work, random forest regression was used to analyze the significance of meteorological parameters that affect the prediction of the NO2/NOx in Kuwait’s three distinct regions—rural, urban, and industrial for the years 2004 to 2014, where different sources of pollution are present in each of these areas. The NO2/NOx ratio did not change much over time for all the studied locations. The measured mean NO2 concentration in the urban regions is two times higher than that in the industrial area, implicating vehicular sources as the major contributor to air pollution compared to stationary sources. The coefficient of determination for NO2/NOx for the four monitoring stations ranged between 0.62 and 0.81. Results indicate that although extreme temperature and intense solar radiation conditions are prominent in each of these areas, wind speed is the relatively important feature that significantly affects the NO2/NOx ratio in urban areas.

A combined analytical-numerical model for predicting temperature profiles in mass concrete foundations continuously cast with two layers of differing thermal properties

Through 57 finite element method investigations on the thermal behavior of a mass concrete foundation cast continuously from two horizontal layers with varying thicknesses and heat properties, this study evaluated the influence of the most important factors impacting the temperature field raised within structure and proposed a predictive model taking seven primary input parameters, including the cement contents of the two concrete layers, curing and placing temperatures, the associated layer thickness ratio, and structural dimensions, into account for predicting the peak temperature ( T max ) and the maximum temperature difference ( Δ T max ) within the massive concrete foundation. The validity of the proposed model is confirmed by comparing its predictions with observations from three published experiments and their corresponding numerical simulations. These comparisons reveal that (i) the proposed model can accurately estimate the values of T max and Δ T max for variously shaped massive concrete structures within a ratio of total surface area to volume ( A / V ) range of 0.84 to 2.8; (ii) despite differing shapes, the massive structures share a similar A / V ratio, leading to similar T max and Δ T max values; and (iii) a proportional relationship exists between T max , Δ T max , and the A / V ratio, with T max decreasing and Δ T max increasing as the A / V ratio decreases.

How 2D and 3D Built Environment Impact Urban Vitality: Evidence from Overhead-Level to Eye-Level Urban Form Metrics

The built environment is the key to creating vibrant urban spaces that contribute to the health and sustainability of cities. Studies have demonstrated that a reasonable built environment helps to stimulate urban vitality. Nevertheless, there are limitations to the understanding that three-dimensional (3D) built environment indicators from the ‘human perspective’ can substantially affect urban vitality. This study provides an empirical analysis of Xi’an, a city with both traditional historical blocks and a modern city landscape. By applying the ordinary least square model and the geographically weighted regression model, this study explores the impacts of the two-dimensional (2D) and 3D built environments on urban vitality. Results show: (1) the urban vitality exhibits significant spatial and temporal difference characteristics; (2) the 3D built environment exerts a greater influence on urban vitality than 2D; (3) taking weekdays for instance, the indicators of green space and road space (e.g., normalized difference vegetation index (−0.092), green view index (−0.104), road density (−0.021), and enclosure (−0.089)) are negatively correlated with urban vitality, while the indicators of building space and mixed function (e.g., building density, floor area ratio, points of interest (POI) mixing degree, and 3D mixing degree) present a positive effect. To improve urban vitality, the study provides suggestions from the perspective of 3D and human perception, which will contribute to the meticulous practice of urban design.

Retrospective radiographic myelogram measurements and long-term outcomes in horses undergoing cervical interbody fusion surgery: 22 cases.

Site selection for cervical stabilization surgery in horses with spinal ataxia frequently relies on measurements derived from radiographic myelography. A variety of measurement criteria exist and can provide conflicting results. The main objectives of this study were to assess the correlation between two commonly used myelographic measures, dorsal contrast column reduction (DCCR) and dural diameter reduction (DDR), and their association with previously selected operative sites in a population of horses operated at a tertiary clinic. Secondary objectives were to determine if articular process joint (APJ) atrophy occurred in a subset of operated horses with radiographic follow-up, and to describe complications of cervical stabilization surgery and long term outcomes. The study was primarily cross-sectional using previously recorded medical information and images from horses operated between 2008 and 2022: three masked raters assessed previously acquired pre-operative myelograms obtained in neutral, flexed and extended neck positions from horses that had subsequently undergone stabilization surgery consisting of cervical interbody fusion via a Kerf-cut cylinder technique at one or two sites. A veterinary radiologist evaluated changes in APJ in radiographs obtained in a subset of horses re-evaluated >18 months after surgery. DCCR was unremarkable at nearly all articulations in all horses, while DDR met reduction criteria at over 50% of articulations in flexed position. Neither DCCR nor DDR distinguished operated from non-operated sites at most intervertebral junctions, except at the C6-7 articulation in neutral and extended position. The two measures were also poorly correlated at most sites and in most positions. Surgical complications included a high incidence of laryngeal hemiplegia. Comparison of operated to non-operated sites within individuals radiographed years later showed consistent, mildly reduced APJ opacity at most operated sites without a consistent decrease in APJ height or area ratios. Our results suggest that DCCR and DDR measures did not reliably predict surgical site selection in this surgical cohort except at C6-7, and that the two measures yielded conflicting diagnostic classification at many sites and positions. Complication rates from stabilization surgery were high; and predictable reduction in APJ height or area after surgery was not demonstrated by radiography in this study.

Influence of localised corrosion shape on adhesive damage and a bonded assembly under thermo-mechanical loading

This study explores the damage prediction of repairs on bonded assemblies through a two-part analysis: simulation and experimentation. The effects of corrosion geometry on adhesive and plate damage were evaluated. In the first part, a three-dimensional finite element method (FEM) was used to analyse a cracked and corroded AL 2024 T3 alloy with a V-notch under thermo-mechanical loading. The analysis included calculating the stress intensity factor (SIF) at the crack tip in mode I at thermo-viscoelastic state, assessing the influence of corrosion geometry, determining the damaged area ratio (DR) for various adhesive configurations, optimising the patch shape for repairs, and examining the effects of crack depth on SIF.The second part involved an experimental investigation on the same bonded assembly under identical conditions. The findings reveal that the circular corrosion shape has minimal impact compared to the square shape, while the rectangular composite patch demonstrated superior performance as an optimal repair solution.

Effect of tempering-induced microstructural evolution on the corrosion behaviour of high chromium cast iron.

This study investigated the effect of tempering heat treatment on the corrosion behaviour of high chromium cast iron (HCCI) in a solution of 0.5 mol dm-3 H2SO4 and 0.01 mol dm-3 HCl. After tempering, microstructural analyses revealed that the primary γ phase transformed into the α phase, accompanied by the precipitation of fine carbides and changes in the composition of the eutectic carbides. Electrochemical and surface analyses demonstrated that the galvanic effect, driven by the area ratio and distance between the carbides and the α phase, accelerated selective corrosion in heat-treated specimens compared to as-casted samples. The preferential dissolution was initiated in either the γ or α phase and propagated towards the eutectic γ phase or inter-eutectic carbides (α) for as-casted and heat-treated HCCI, respectively. Consequently, heat treatment accelerated the corrosion rate by intensifying galvanic interactions.

The Growth Hormone-IGF-1 axis is a risk factor for Long-Term Kidney Allograft Failure.

Maladaptive hypertrophy, podocyte stress, and depletion contribute to kidney function decline. Although IGF-1 plays a key role in early hypertrophic responses in the single kidney state, its impact on KTx outcomes remains uncertain. This report tests the hypothesis that early IGF-1 exposure reduces KTx survival. Population datasets compared incident Death Censored Graft Failure (DCGF) rates by age at KTx (n=366,404) with IGF-1 levels by age (n=15,014). A clinical study of 216 KTx recipients evaluated the association of IGF-1 exposure with DCGF and secondary outcomes of proteinuria and Biopsy-Proven Acute Rejection. IGF-1 exposure was modeled using pre-KTx IGF-1 levels and donor kidney dose estimated from the donor:recipient body surface area ratio reflecting allograft hyperfiltration. The association of DCGF with an IGF1 SNP linked to high IGF-1 levels was assessed in 724 genotyped allograft recipients. Single-cell transcriptomic data from first-year post-KTx patients and binephric donors were compared to assess intrarenal cellular expression of IGF1, IGF1R, and GHR transcripts. DCGF risk by age at KTx paralleled IGF-1 levels by age. Higher IGF-1 exposure was associated with significantly increased risks of DCGF, proteinuria, and T-cell-mediated rejection. Genotypic analysis showed a 50% increase in DCGF risk per risk allele at IGF1 eQTL rs35767. First-year biopsy results revealed no increase in intrarenal IGF1 transcript, while GHR and IGF-1R transcripts were suppressed, consistent with circulating IGF-1 (vs. graft-derived IGF-1) being the primary source of IGF-1 exposure. We identify a role for the GH-IGF-1 axis in reducing KTx survival.

Population pharmacokinetics of intravenous fosfomycin: dose optimization for critically ill patients with and without kidney replacement therapy.

We investigated the pharmacokinetics (PK) of intravenous fosfomycin in critically ill patients undergoing different types of kidney replacement therapy (KRT) to identify optimized dosing regimens for patient care. Four prospective, observational studies contributed data of critically ill patients with prolonged-intermittent KRT (PIKRT, n=18), continuous KRT (CKRT, n=15), or without KRT (n=12) for population PK analysis. Subsequently, licensed daily dosages (12-24 g), varying estimated glomerular filtration rates (eGFR, 0-120 mL/min/1.73 m2), and scenarios with or without KRT were simulated for comparison against minimum inhibitory concentrations (MICs, 32-256 mg/L). A dosing regimen was considered "effective" if the ratio of area under the concentration-time curve from 24-48 hours and MIC (AUC24-48/MIC ratio) exceeded 22.7 or 83.3, respectively, and if the percentage of time above MIC between 24 and 48 hours (%T24-48>MIC) was greater than 69.0. The probability of target attainment (PTA) was assessed using Monte Carlo simulations (n = 2,000) for each scenario. A two-compartment model incorporating body (1.6 L/h) and dialysis (2.0 L/h) clearance identified eGFR, dialyzate flow rate (QD), and time after first dose as significant covariates. Considering the AUC24-48/MIC ratio, 8 g three times daily (TID) was bactericidal (PTA≥90%) in all scenarios at MIC32, 5 g TID was bacteriostatic (PTA≥90%) at MIC64, and 8 g TID was also effective (PTA≥90%) at MIC128. Based on the %T24-48>MIC, 4 g TID and 8 g TID were bactericidal (PTA≥90%) at MIC32 and MIC64, respectively. In conclusion, a dosage of 12-24 g/d intravenous fosfomycin is plausible for critically ill patients undergoing CKRT or PIKRT.

Optimizing glass roof design for green buildings by evaluating co-benefit of indoor daylighting and cooling load

Glass roofs have become a pivotal element in the design of green buildings, playing a crucial role in balancing daylighting and heat gain performance. This research aims to investigate the cooling load and daylight illuminance under various glass roof design parameters. Firstly, three primary design parameters were identified and parameterized: tilt angle, material and skylight-to-roof area ratio (AR). Secondly, a simulation model was developed to evaluate the photothermal performance of glass roofs under four different materials. Thirdly, a co-benefit evaluation method was introduced to quantify the impacts of the design parameters of glass roofs on daylighting and heat gain performance. The results showed that co-benefit indicators rose from 0.56% to 30.95% with the increase in transparency and heat transfer efficiency. Amongst Materials 1 to 4, co-benefit variation grew from 0.002% to 7.15%, showing that the optimal glass roofing combination varied based on design parameters. Glass Roof Material 2, with a tilt angle of 10° and a skylight-to-roof AR of 10%, was identified as the optimal option. Finally, the co-benefit evaluation method for photothermal performance was applied to a real building. Co-benefit index gradually increased from 28.16% baseline to 71.04% for Material 2. The proposed method can generate optimal values for each type of building glass roofs, providing designers with valuable design recommendations tailored to their specific needs.

Branch-to-Total Pulmonary Artery Area Ratio as a Predictor of Flow Limitation in Tetralogy of Fallot: MRA and Phase Contrast MRI Study

Branch-to-Total Pulmonary Artery Area Ratio as a Predictor of Flow Limitation in Tetralogy of Fallot: MRA and Phase Contrast MRI Study

Declining growth and changes in biomass allocation with warming in rainforest trees from temperate to tropical climates.

Australian rainforests occur from temperate to tropical latitudes, but how climate warming will affect tree growth along this climate gradient remains poorly understood. We examined how changes in biomass allocation, leaf area, and photosynthetic capacity were linked to the capacity of these species to maintain growth rates with +3.5°, +7° and +10.5°C warming in seedlings of tropical, subtropical and temperate rainforest trees. Temperate species maintained or increased final biomass (+14%), leaf area (LA) and leaf area ratio (LAR, the ratio of leaf area to plant dry mass) with warming along with similar or increased leaf mass fraction (+14%). Subtropical species increased biomass with +3.5° (+28%) and +7 °C (+17%) warming but were negatively impacted with >10 °C warming (-31%). Tropical species reduced LA, LAR, photosynthetic capacity and leaf nitrogen, along with 14% increased root allocation in response to warming, resulting in large biomass reductions with +3.5 °C (-20%) and +7 °C (-53%). Tropical species were more susceptible to climate warming with reduced photosynthetic capacity and reduced biomass which can lead to a reduced carbon sink in the future, especially in late-successional tree species which are the most abundant with a large role in carbon assimilation of tropical rainforests.

The Role of Financial Statement Analysis While Predicting Business Failure with Reference to RCom

This study explores the function of financial statement analysis as an early warning tool for predicting corporate financial distress using Reliance Communications (RCom) as a case study. RCom, a giant in India's telecommunications market, suffered a tremendous financial decline that ended in insolvency proceedings by 2019. This study assesses whether warning signs of business failure existed early using common financial ratios and bankruptcy forecasting models. We employed a quantitative approach to examine the secondary data of RCom's audited financial reports from 2014 to 2019. The financial ratios of key areas, such as profitability, liquidity, solvency, and efficiency, were examined to outline the course of the company's finances. The Altman Z-score and Ohlson O-score were also used to determine the probability of failure. The results show a steady downward trend in finance from 2015, with both models correctly forecasting distress long before bankruptcy. The research concludes that careful financial analysis, backed by forecasting models, can serve as a sound early warning system for stakeholders, particularly in capital-intensive industries, such as telecommunications.

Impact of Changes in Blue and Green Spaces on the Spatiotemporal Evolution of the Urban Heat Island Effect in Ningbo and Its Implications for Sustainable Development

Blue and green spaces (BGS) play a crucial role in mitigating the urban heat island (UHI) effect by not only lowering land surface temperature (LST) but also regulating the urban microclimate and enhancing ecosystem services. In this study, Ningbo City is selected as the research area. LST data for the years 2014, 2017, 2020, and 2023 were retrieved using Landsat 8 imagery processed via the Google Earth Engine platform, employing an atmospheric correction approach. Simultaneously, land use types were classified using the random forest algorithm. Based on these datasets, a Geographically and Temporally Weighted Regression model was employed to quantitatively assess the spatial and temporal impacts of BGS changes on the UHI effect. The results reveal that (1) from 2014 to 2023, BGS in Ningbo exhibited a consistent decline, while construction land expanded significantly, leading to a gradual increase in the annual average LST; (2) strong UHI zones were primarily concentrated in urbanized zones and closely aligned with regions of elevated LST; the minimum, maximum, and average LST values in blue and green spaces were significantly lower than those observed in cultivated land and construction land; (3) the variation in the influence coefficient of blue space on LST was greater than that of green space, suggesting stronger spatiotemporal heterogeneity in its regulatory effect on the urban thermal environment. Additionally, the green-to-blue space area ratio increased from 9.7:1 in 2014 to 12.8:1 in 2023, deviating progressively from the optimal ecological balance. To promote sustainable urban development, it is imperative for Ningbo to strengthen the conservation and restoration of BGS, optimize their spatial configuration through evidence-based planning, and ensure the long-term stability of ecological functions.

Effect of Combined Oral Contraceptive on Flap Surgery in Female Rat Model

Combined oral contraceptives (COCs) are said to have a negative effect on flap surgery's outcomes due to their adverse effects on tissue perfusion, managing inflammation, and oxidative stress. This study aimed to investigate the effects of COCs use on flap survival in a female rat model. In this randomized controlled experimental study, a total of 20 female Wistar Albino rats were divided into control and COC groups (n=10/group). The COC group received Desolett® (Desogestrel 0.15 mg, Ethinyl estradiol 0.03 mg) orogastrically for three weeks. The McFarlane flap model was surgically implemented, and flap survival was evaluated using digital planimetry. Histopathological and biochemical analyses were performed during the postoperative period. The flap survival rate in the COC group was significantly lower compared to the control group (74.4 vs 83.7%, P=0.012). Furthermore, the COC group demonstrated a higher necrotic area ratio (25.7 vs 18.4%, P=0.015) and more severe inflammatory cell infiltration (2.4 ± 0.5 vs 1.8 ± 0.4, P=0.011). Biochemical analyses revealed higher malondialdehyde (MDA) levels (4.86 ± 0.72 vs 3.24 ± 0.58 nmol/mg, P=0.008) and lower superoxide dismutase (SOD) activity (14.2 ± 2.1 vs 18.5 ± 2.4 U/mg, P=0.012) in the COC group. Using COCs reduces the chances of a successful flap surgery and promotes the chances of complications arising owing to oxidative stress, inflammation and impairment of tissue perfusion. These observations merit caution while planning flap surgery for COCs users and a recommendation for a brief halt in the usage of COCs should be made. The results underscore the importance of understanding the potential implications of COCs use in surgical planning and postoperative care management.

Factors associated with diplopia before and after orbital blowout fracture reconstruction.

To ascertain factors associated with persistent diplopia after orbital fracture reconstruction. In this retrospective study, we reviewed 798 cases with depressed fragment fracture at the Department of Kyoto Prefectural University of Medicine Hospital between January 2009 and November 2023. The restriction of extraocular movements and diplopia was assessed using the Hess area ratio (HAR). The factors for HAR% ≥85% before surgery and 6 months after surgery were assessed. Of the 798 cases in this study, 437 cases (54.8%) had an HAR% of ≥85%, and 361 cases (45.2%) had an HAR% of <85% before surgery. Age ≤18 years old (p=0.017), orbital tissue herniation volume <median (p=0.001), absence of extra-ocular muscle deviation (p<0.001) and medial wall (vs medial wall and orbital floor with strut fracture; p<0.001) were found to be associated with HAR% ≥85% before surgery. Of the 332 cases treated with surgery, 272 cases (81.9%) were HAR% ≥85%, and 60 cases (18.1%) were HAR%<85% after surgery. Age ≤18 years old (p=0.011), male (p=0.014), absence of extra-ocular muscle deviation (p=0.002) and medial wall (vs medial wall and orbital floor with strut fracture; p=0.002) were found to be associated with HAR% ≥85% at 6 months post surgery. Patients of younger age, male and those with absence of extraocular muscle deviation have better eye movements in the affected eye (increased HAR%) 6 months after surgery.

Research on the influence of the visual perception characteristics of fitness trail landscape space based on psychological perception: a case study of Hunnan District, Shenyang, China

Based on the multidisciplinary method of collaborative psychology, sociology and environmental design research, this study conducts a quantitative study on the relationship between the visual perception of fitness trail landscape space and the psychological perceptions of fitness activities, providing data-driven references for the design of fitness trials. First, self-image acquisition is used to form a fitness trail landscape space image material library including 646 pictures. Second, we identify the user preferences for the composition of the main landscape elements of fitness trails, with subsequent research focusing on the top two preference combinations, namely, “plant–plant” and “plant–water.” Third, on the basis of the results of the semistructured interviews, a word frequency analysis is conducted, and the visual perception feature index framework of the fitness trail landscape space containing 12 indicators is constructed in combination with the relevant literature. An image semantic segmentation process, along with manual auditing, is applied to the self-collected images, resulting in a dataset of visual perception characteristic indicators. Furthermore, based on the KANO model, a psychological perception evaluation framework is constructed, and psychological perception evaluation datasets are obtained by using the semantic differential (SD) method. Finally, correlation analysis, multiple regression, and curve fitting are applied to the two datasets and the relevant threshold ranges are obtained. The results show that within the “plant–plant” combination, the optimal threshold for the degree of enclosure is 66–81%, the optimal threshold for the green view rate is 62–78%, the optimal threshold for the degree of openness of the sky is 2.2–3.2%, and the optimal threshold for the building façade area ratio is 0–10%. For the “plant–water” combination, the optimal threshold for the green view rate is 58–68%, the optimal threshold for the openness of the sky is 4.1–6.0%, the optimal threshold for the water area ratio is 0.75–1.75%, and the optimal threshold for the road area ratio is 33–43%.

Simulation Study on Engine Nozzle and Afterbody Drag Characteristics of Flying Wing Configuration

Abstract In order to study the characteristics of engine exhaust system and afterbody drag of flying wing aircraft, and explore the methods and characteristics of nozzle characteristics and afterbody drag increment in the determination of engine available thrust, the performance characteristics of serpentine nozzle and the determination methods of afterbody drag increment of flying wing configuration and serpentine nozzle were studied based on CFD simulation method, taking Serpentine two-dimensional tail nozzle and B-2 aircraft fuselage model as the research object. The results show that the discharge coefficient and thrust coefficient of the double S curved 2-D nozzle are smaller than those of the axisymmetric nozzle with the same inlet/outlet area ratio, and the maximum difference of thrust coefficient is 4.0%; The nozzle pressure ratio affects the afterbody drag of the flying wing configuration. When the flight Mach number is small, the afterbody drag increases with the increase of the pressure ratio. When the Mach number is large, the afterbody drag decreases with the increase of the pressure ratio; The database of afterbody drag coefficient increment under other engine conditions is established by CFD method, and the afterbody drag increment under a certain flight condition is predicted accordingly. The research method and results have important reference value for determining the installation net thrust of power plant with this kind of layout.