Search Results (1,053)

Background/Objectives: Anthracyclines carry considerable cardiotoxicity risk, and atrial fibrillation (AF) during cancer treatment adversely affects morbidity and mortality. We compared the incidence of clinically documented AF and explored its early clinical correlates between anthracycline-containing and non-anthracycline adjuvant regimens in triple-negative breast cancer (TNBC). Methods: This single-centre retrospective cohort included consecutive women with stage II TNBC treated with breast-conserving surgery and adjuvant doxorubicin–cyclophosphamide followed by docetaxel (AC-T) or docetaxel–cyclophosphamide (TC) between 2018 and 2023. ECG and echocardiography were performed at baseline, month one, and month six. Clinically documented AF was defined as AF documented on a scheduled or symptom-triggered 12-lead ECG or as AF lasting ≥30 s on symptom-triggered 72 h Holter monitoring. Patients with structural or coronary heart disease, complete bundle branch block, or non-sinus rhythm were excluded. Results: Among 140 women (mean age, 64 ± 12 years; 64 AC-T), 17 (12.1%) developed clinically documented AF within six months. AF was more frequent with AC-T (18.8% vs. 6.6%; absolute risk difference, 12.2% [95% CI, 1.1–23.3%]; risk ratio, 2.85 [1.07–7.58]; log-rank p = 0.030), and the association persisted after inverse probability of treatment weighting (OR, 3.28 [1.05–10.24]). At one month, PR prolongation > 20 ms was associated with incident AF (OR, 5.16 [1.79–14.89]), whereas conventional echocardiographic changes did not differ between regimens. Conclusions: The AC-T regimen was associated with more clinically documented incident AF than TC. Early PR prolongation, occurring without detectable changes in conventional echocardiographic parameters, may be an informative early electrical signal of AF risk, although prospective validation is required. Full article

Background: Transthoracic echocardiography (TTE)-assisted left bundle branch area pacing (LBBAP) is a potential supplementary to fluoroscopy-guided implantation and may reduce radiation. Objectives: To evaluate the feasibility and long-term stability of TTE-assisted, low-fluoroscopy LBBAP across different workflows and lead types. Methods: This retrospective study enrolled 45 consecutive patients between November 2021 and June 2022, analyzing 42 successful cases. Patients were stratified by workflow approach (non-scrubbed, n = 24; scrubbed aseptic, n = 18) and lead type (lumen-less leads [LLLs], n = 20; stylet-driven leads [SDLs], n = 22). Procedural and pacing parameters were assessed through a 4-year follow-up. Results: In select patients with adequate acoustic windows, multi-stage TTE-assisted LBBAP remained feasible despite a 54.8% overweight/obesity rate. The scrubbed aseptic workflow showed significantly shorter procedural and fluoroscopy times (p < 0.01), though confounded by the learning curve. Beyond 6 months, pacing parameters remained stable and comparable between workflows through 4 years. Regarding lead types, procedural durations were similar. However, the SDL group exhibited significantly higher pacing thresholds at implant and 6 months (p < 0.05) and maintained a higher numerical trend through Year 4, though both lead types demonstrated stable chronic sensing and impedance profiles. No late dislodgements, device-related infections, or late complications occurred across available patient-years. Conclusions: TTE-assisted LBBAP is a clinically feasible approach that can supplement conventional implantation in selected patients with favorable acoustic windows. While achieving excellent 4-year functional durability, procedural improvements reflect the combined effect of workflow refinement and operator proficiency. Full article

This paper presents BSTwin, a computational workflow and application for the automatic generation of multi-level-of-detail building models and semantically enriched building stock records in urban areas of Slovakia. Its outputs are positioned as the building layer of a city information model (CIM) that can support future urban digital twin applications, not as an operational digital twin. BSTwin couples a lightweight, rule-based roof reconstruction engine for airborne LiDAR point clouds with a benchmark dataset mined from 13 open geodata sources: national registers (INSPIRE HVD Buildings, 2021 CENSUS, INFOREG-EC), European and global datasets (European building stock (EUBUCCO v0.2), Global Human Settlement Layer (GHSL R2023A), Copernicus Urban Atlas, GlobalBuildingAtlas (GBA), OpenBuildingMap (OBM), Microsoft Global Building Footprints) and open-source maps (OpenStreetMap, Overture Maps). Rather than proposing new learned segmentation models, the approach integrates published geometric methods (normal-seeded RANSAC with Hough parameter-space merging, ring-based ground estimation, 3DBAG reference heights, mSTEP azimuth rectification and recursive footprint decomposition) into a deterministic pipeline that runs on an ordinary computer without GIS/BIM software. The term GeoAI is used in its knowledge-driven sense, since no machine-learned model is involved. Each reconstruction and integrated attribute is verified through a quality-control block. On synthetic ground truth, the engine classified all five tested roof archetypes correctly with a point-to-plane RMSE of about 5 cm; on real national LiDAR covering 1468 buildings in the Staré Mesto district of Košice, it reconstructed 99.9% of the buildings, 96.2% of them without a quality flag, in a median of 0.20 s per building. The LiDAR ridge heights agreed with the INSPIRE register heights with a median difference of +0.48 m (65% within 1 m). For the Košice Self-governing Region, the bundled EUBUCCO v0.2 extract covers 488,363 buildings, 81.7% of which have heights of governmental origin. The findings indicate the potential of the workflow for building stock monitoring, renovation planning and as a data foundation for future urban digital twins. Full article

Background: Reverse remodeling after cardiac resynchronization therapy with defibrillator backup (CRT-D) is heterogeneous and may reflect both pre-implant substrate and post-implant electrical response, with implications for subsequent outcomes. Objectives: This study evaluated a graded echocardiographic response framework after CRT-D as an integrative phenotype linking pre-implant substrate, peri-implant electrical features, and post-landmark clinical outcomes. Methods: The analytic cohort included 334 CRT-D recipients with complete four-group classification based on relative left ventricular end-systolic volume reduction at the first eligible post-implant echocardiogram. Baseline correlates of the 4-class response phenotype were assessed using ordinal logistic regression, supported by permutation-importance analysis. A stacked peri-implant model added ΔQRS, RV1SI pattern on ECG, left ventricular lead position, and lead depth. Time-to-event analyses used a landmark design anchored at the first post-CRT echocardiogram. Results: In the pre-implantation ordinal model, female sex (p = 0.005), higher baseline left ventricular ejection fraction (p = 0.032), left bundle branch block (p = 0.038), and dilated cardiomyopathy (p = 0.048) were associated with a more favorable response class. In the stacked peri-implant model, ΔQRS was the strongest correlate of higher response class (OR: 1.41; 95% CI: 1.15–1.73; p = 0.0008). Mortality differed across response classes (log-rank p < 0.001); compared with super-responders, negative responders had higher adjusted mortality (HR: 4.41; 95% CI: 1.82–10.70). At 60 months, heart failure hospitalization ranged from 23.3% to 2.9% and first appropriate ICD shock from 29.3% to 9.0% from negative responders to super-responders. Conclusions: After CRT-D, reverse-remodeling phenotype identified clinically distinct post-landmark risk profiles. Less favorable remodeling was associated with worse mortality, heart failure hospitalization, and appropriate ICD shock. Full article

Biological fineness of cotton fibers significantly affects spinning performance and yarn quality, yet reliable high-throughput measurement is hindered by morphological variability and limitations of conventional cross-sectional methods. This study developed an automated microscopic imaging system for rapid measurement of cotton fiber phenotypic features from longitudinal-view images, eliminating the need for fiber cross-sectioning. The system integrated a light microscope equipped with a three-axis motorized stage and a high-resolution digital camera for automated scanning and image acquisition. At each (x, y) location, a z-stack of images is captured, and in-focus pixels are fused into a single extended depth-of-field (EDF) image. The EDF images are segmented using Meta’s Segment Anything Model, with prompt points automatically generated from fiber skeletons to separate overlapping fibers. The segmented fiber ribbons are scanned transversely along their centerlines to extract ribbon width, image intensity, and intensity variability, which are incorporated into an empirical model to estimate the fiber perimeter (P). Individual measurements from a slide are aggregated to characterize the distribution of P for each cotton sample. The proposed method demonstrated high repeatability across multiple replicates and independent tests. The estimated P showed strong correlations with AFIS gravimetric fineness (r ≈ 0.80) and with HVI bundle strength (r ≈ −0.95), and a moderate correlation with HVI micronaire (r ≈ 0.65). A preliminary validation test against the cross-sectional method suggested that the perimeter distributions obtained from the estimated and cross-sectional measurements did not differ statistically and were highly correlated (r > 0.960). Full article

Background: Multidisciplinary rounds are essential for high-quality intensive care but are frequently hindered by inconsistent team participation and logistical inefficiencies. We evaluated the associated impact of implementing a standardized multidisciplinary rounding checklist and real-time paging system on multidisciplinary team attendance, rounding efficiency, and selected clinical outcomes in the ICU. Methods: A retrospective, observational pre- and post-intervention cohort study featuring a concurrent control group was conducted at a tertiary care hospital. The study included 331 adults admitted to the medical ICU (MICU) and neurovascular critical care unit (NCCU; control). The intervention combined a standardized rounding checklist incorporating the ICU Liberation (ABCDEF) bundle and FAST HUGS BID mnemonic with a real-time paging notification system to alert team members of round start times and locations. The primary outcome was change in multidisciplinary team participation at the start and end of rounds; secondary outcomes included rounding time per patient and exploratory care-process outcomes. Results: Multidisciplinary participation at the start and conclusion of rounds significantly improved for both the MICU advanced practice provider (APP) team (p = 0.003 and p = 0.002, respectively) and the resident team (p = 0.006 and p < 0.001, respectively), while attendance in the NCCU group remained unchanged. Median rounding time per patient decreased by 20.8% (13.0 to 10.3 min, p < 0.001). In a survivor-only sensitivity analysis, the streamlined workflow decreased the median time to physical and occupational therapy consultations from 4 to 2 days (p ≤ 0.002). Invasive device stewardship significantly improved; central venous catheter utilization decreased from 58.0% to 25.0% (p < 0.001), and arterial line utilization fell from 55.0% to 26.5% (p < 0.001), with median arterial catheter duration decreasing from 5 to 3 days (p = 0.001). Conclusions: Implementing low-cost, reliable workflow standardization tools was associated with significantly improved multidisciplinary participation and shorter rounding time per patient. Favorable changes in selected care-process measures were also observed, although patient-level clinical outcomes should be interpreted as exploratory and future studies are warranted. Full article

Background/Objectives: Surgical site infection (SSI) remains a common complication after ileostomy closure. Mechanical bowel preparation (MBP) and oral antibiotic preparation are often bundled together, so their independent contributions to SSI risk are unclear. We evaluated the adjusted associations of oral antibiotic preparation and MBP with SSI after ileostomy closure, a setting in which these two components have rarely been examined separately. Methods: We retrospectively reviewed 432 consecutive patients undergoing loop or end ileostomy closure at a single center between January 2022 and December 2025. SSI was defined per Centers for Disease Control and Prevention/National Healthcare Safety Network (CDC/NHSN) criteria. Multivariable logistic regression was used to assess adjusted associations with SSI, with MBP and oral antibiotic preparation included as the exposures of primary interest, adjusting for adjuvant oncologic therapy and closed suction drain use—the covariates associated with SSI on univariate analysis. Results: SSI occurred in 35 patients (8.1%). Oral antibiotic preparation was associated with a lower SSI rate (2.9% vs. 11.5% without; absolute risk reduction 8.5 percentage points, unadjusted descriptive number needed to treat 12; p = 0.003), while no statistically significant unadjusted association was detected for MBP (p = 1.000). After adjustment, oral antibiotic preparation was associated with lower odds of SSI (odds ratio [OR], 0.21; 95% confidence interval [CI], 0.08–0.56; p = 0.002), whereas no statistically significant adjusted association was observed for MBP (OR, 1.21; 95% CI, 0.58–2.53; p = 0.610); this confidence interval is compatible with both a clinically meaningful benefit and a clinically meaningful harm of MBP, and the study is not powered to exclude either. Adjuvant oncologic therapy (OR 2.53, 95% CI 1.23–5.20) and closed suction drain use (OR 2.33, 95% CI 1.14–4.77) were associated with higher adjusted odds of SSI. The model showed acceptable discrimination (area under the receiver operating characteristic curve [AUC] = 0.745), with no evidence of poor fit on a covariate-pattern-based goodness-of-fit assessment (χ² = 11.37, df = 14, p = 0.657). A Firth penalized-likelihood model, used because of the limited number of events in the antibiotic-exposed group, gave materially unchanged estimates (OR 0.23, 95% CI 0.09–0.58). Conclusions: Oral antibiotic preparation was associated with lower adjusted odds of SSI after ileostomy closure, whereas the association with MBP remained inconclusive. This observational association should not be interpreted as evidence of causality, because residual confounding—particularly by surgeon-level practice—cannot be excluded. These findings should be considered hypothesis-generating and require confirmation in prospective studies using standardized preparation protocols. Full article

Endmember extraction (EE) in an unmixing chain aims at determining source component spectra constituting pixels from hyperspectral imagery. However, the influence of spectral variability, nonlinear manifolds, and outliers on datasets can seriously degrade EE’s reliability even if pure pixels exist. Improving EE’s accuracy and applicability across heterogeneous scenarios remains a challenge. In this paper, we propose a novel unit-simplex-inspired graph attention network (GAT) to identify endmembers based on the pure pixel assumption. First, the geometric relationship between pixels in a constructed graph is incorporated into a network architecture which integrates spectral feature learning with GAT-driven adaptive information aggregation and inference among neighboring pixel nodes. Second, a unit-simplex maximization rule is exploited to guide the network’s training without relying on data reconstruction, producing pixel purity representations. The normalized purity of pixels with respect to different land covers depends on their geometric positions and relations on the data manifold. Finally, candidate endmember bundles consisting of pixels with high purity are recognized, and the purest pixels in each endmember bundle are identified as the endmembers because their purity feature vectors construct the largest unit simplex. The pixel purity-based characterization of endmembers’ spatial distributions enables geometrically meaningful discrimination between endmember and non-endmember nodes in a graph, also improving EE’s robustness to interfering factors. Extensive experiments conducted on different types of simulated datasets and three real hyperspectral images demonstrate that the proposed method has competitive performance and improved robustness under heterogeneous scenarios, despite its limitations in dealing with highly mixed data. Full article

Background: This study assessed diet quality and the association between engagement with nutrition support bundles and weight gain among pregnant women having Aboriginal and Torres Strait Islander babies who participated in the Aboriginal Family and Baby Bundles implementation project at two South Australian maternity sites. Methods: Cross-sectional analysis of dietary data was performed using the Australian Recommended Food Score (ARFS) at enrolment, and 24-h food group servings were compared between enrolment and late pregnancy visits. A composite variable for engagement with nutrition support bundles (low vs. high engagement) used initiation, intensity, and duration of engagement criteria. Separate regression models were applied to examine associations between ARFS, adherence to 24-h food serve recommendations, and maternal characteristics at enrolment. An exploratory univariable association between engagement status and gestational weight gain was examined. Results: The median ARFS score at enrolment was 39 (maximum of 62 out of a total of 73). Women aged above 25 years showed significantly higher ARFS compared with those aged 25 years and below (adjusted β coefficient 3.28, 95% CI 0.38, 6.19, p = 0.027). The number of participants meeting the recommended intake of daily fruit serves increased significantly at the late pregnancy visit (McNemar test p value = 0.004). Across pregnancy, consumption of energy-dense soft drinks or snack foods was common (60–68%). Only 15.4% (8/52) of participants showed adequate weight gain, while 26.9% (14/52) showed inadequate weight gain, and 57.7% (30/52) showed excessive weight gain, as per the recommendations for total gestational weight gain. In the high nutrition support engagement group, a higher proportion of adequate weight gain (24.0% vs. 7.4%) and a lower proportion of excessive weight gain were observed (28.0% vs. 85.2%) (p ≤ 0.001) compared with the low engagement group. Conclusions: This study identified sub-optimal diet quality, including high intake of energy-dense food throughout pregnancy and high proportions of inadequate and excessive weight gain among women having Aboriginal babies in South Australia. Further research is needed to determine the most appropriate ways to support healthy eating in pregnancy among women in South Australia. Full article

Background: Patients awaiting bariatric surgery face permanent anatomical change, lifelong behavioural adaptation, and uncertainty about weight-loss maintenance; consequently, they report high levels of surgical fear and state anxiety. Immersive 360° virtual nature exposure delivered through a head-mounted display is a low-cost, nurse-deliverable, non-pharmacological option, but its effect on surgical fear specifically, and in bariatric candidates in particular, is largely untested. The aim was to determine whether a single 20 min session delivered in the immediate preoperative period reduces surgical fear and state anxiety in patients scheduled for laparoscopic sleeve gastrectomy. Methods: A single-centre, two-arm, parallel-group randomised controlled trial was conducted in a general surgery clinic between March 2025 and June 2026 and is reported in accordance with the CONSORT 2025 statement (ClinicalTrials.gov NCT07774156; registered retrospectively on 18 August 2026). One hundred and twenty adults scheduled for laparoscopic sleeve gastrectomy were randomly allocated 1:1, using sequentially numbered opaque sealed envelopes, to the intervention or to routine care. Two hours before transfer to theatre, the intervention arm viewed a single 20 min 360° nature video with a natural soundtrack through a head-mounted display; the control arm received the standard clinical protocol. Premedication was administered after post-testing in both arms. Surgical fear (Surgical Fear Questionnaire, SFQ) and state anxiety (State Anxiety Inventory, STAI-S) were measured before and after the intervention period. The primary analysis was a baseline-adjusted comparison of post-test SFQ; because the homogeneity-of-regression-slopes assumption was violated, a group-by-baseline interaction model was used, and conditional treatment effects were reported. All other analyses were exploratory. Results: All 120 patients completed the trial. In the interaction model, the estimated control minus intervention difference in post-test SFQ was significant across the entire observed baseline range, from 11.43 points (95% CI 5.59 to 17.27) at a baseline score of 0 to 26.37 points (95% CI 18.35 to 34.40) at a baseline score of 80, and was 17.19 points (95% CI 13.38 to 20.99) at the sample mean baseline. Post-test state anxiety was lower in the intervention arm by 24.87 points after baseline adjustment (95% CI −27.33 to −22.41; F(1, 117) = 400.84, p < 0.001). Surgical fear fell by 8.68 points in the intervention arm and rose by 8.22 points in the control arm; state anxiety fell by 18.75 points and rose by 7.15 points, respectively. Forty-five per cent of participants gave identical responses to all eight SFQ items at post-test, and when these participants were excluded, the between-group difference in post-test SFQ fell to 10.66 points (p = 0.029), and the baseline interaction disappeared. Conclusions: A single 20 min session of immersive 360° virtual nature exposure was followed by substantially lower surgical fear and state anxiety than routine care, under which both increased over the same interval. The magnitude of these effects greatly exceeds pooled estimates from the existing literature and should not be attributed to the virtual reality content itself: the comparator was routine care rather than an attention-matched control, so the contrast reflects a bundle of immersive stimulation, novelty, protected quiet time, and individual researcher attention; the trial was unblinded with self-reported outcomes; and a substantial response-set pattern in the SFQ data may have inflated the apparent effect on surgical fear. The findings support further evaluation in attention-controlled trials rather than immediate adoption. Full article

Sustainable consumption is central to sustainable development goals (SDGs), yet research on consumer behavior (CB) remains scattered. Studies on green consumption, digital retail, fashion, food systems, digital finance, energy, and tourism have developed largely in isolation, and few studies have investigated what these settings share or how sustainability-relevant behavior unfolds after the moment of purchase. This study takes a wider view, applying the SPAR-4-SLR protocol to a decade of CB and sustainability scholarship and combining machine-learning-based BERTopic thematic modeling with SDG mapping, organized through a Theory–Context–Method and Antecedents–Decision–Outcome (TCM–ADO) lens. Seven themes emerged, concentrated on SDGs 8 (decent work), 9 (industry innovation), and 12 (sustainable consumption). Together, they point to a shift away from individual purchase choices toward consumption that is multistage, digitally mediated, and institutionally embedded. Across the seven theme-level summaries, trust, engagement, risk perception, ethics, literacy, and experience appear repeatedly. Because several of these constructs were included in the retrieval query, this pattern is interpreted as cross-theme recurrence within the query-defined corpus rather than as independent evidence of universal prevalence across sustainable consumer-behavior research. Digital and platform mediation appears as one cross-cutting condition, and is most visible where consumption is heavily platform-based. On this basis, the review proposes a process framework that treats antecedents as capability, vulnerability, and layered trust; decisions as multistage and mediated; and outcomes as interdependent SDG bundles. Twelve propositions and a research agenda follow, testable across food, energy, finance, fashion, tourism, and digital retail. Full article

Background/Objectives: We aimed to evaluate the temporal associations and heterogeneous patterns between the Beijing Diagnosis-Related Group (DRG) 2.0 payment reform and hospitalization costs and resource utilization among patients receiving major colorectal cancer (CRC) surgery and to explore hospital adaptive cost adjustment behaviors under bundled payment constraints. Methods: Utilizing inpatient data of 1232 colorectal cancer surgical patients from a Beijing hospital spanning January 2021 to October 2024, we adopted segmented regression interrupted time-series analysis (ITSA), with April 2022 defined as the policy intervention point. The analysis used total hospitalization expenses, itemized costs, cost composition proportions, and length of stay (LOS) as outcome indicators, conducted heterogeneity analysis, and applied seasonal autoregressive integrated moving average (SARIMA) counterfactual forecasting as a supplementary sensitivity check. All medical expenditures were inflation-adjusted based on Beijing’s medical consumer price index (CPI), with 2024 as the base year. Results: After DRG implementation, total hospitalization costs showed an immediate decrease of 13,111.73 CNY and a sustained monthly downward trend of 1312.60 CNY. Medical consumable fees were the main component associated with total-cost reduction, and their proportion declined immediately by 4.1 percentage points. LOS showed no abrupt immediate decline but shortened by 0.22 days per month over the post-reform period. Heterogeneous association patterns were observed across selected clinical and treatment subgroups. SARIMA counterfactual forecasting provided supplementary, directional sensitivity evidence for the primary outcomes and was interpreted cautiously for volatile sub-item expenditures. Conclusions: DRG 2.0 reform was associated with lower hospitalization costs and improved bed-turnover efficiency among CRC surgical patients, mainly through reductions in consumable expenditures. Full article

The knot-forming motions of knotters are difficult to directly observe, and knotting tests are labor-intensive and time-consuming. To address these issues, a novel test bench motion scheme was proposed to simulate the bundling process of a bale, and a performance test bench for a single-knot knotter was developed under controllable indoor conditions. The bench can verify the working principles of different knotters and assess the knotting success rate. To meet the requirements of unattended and safe operations for long-term continuous knotting tests, an automatic control process for the test bench was constructed to identify the knot-releasing failure and twine breakage fault based on monitoring the pressure of the simulated bale. By establishing the corresponding relationships between knotting actions and image states, a test and analysis method for detecting the motion timing sequences of the knotter was developed. This allowed us to obtain a motion timing diagram of the knotter, which can provide references for its reverse design or performance evaluation. The results of the continuous knotting tests show that the tested knotter achieved a knotting success rate of 99.57%, and the test bench can meet the performance testing requirements of the knotter. Full article

Objectives: The collaborative “Stop Hospital Infection 2.0”, implemented in Portugal between 2023 and 2025, aimed to reduce the incidence of catheter-associated urinary tract infection (CAUTI), ventilator-associated pneumonia (VAP) and central-line associated bloodstream infection (CLABSI) by 50.0% in 21 hospitals. Methods: The project followed the Breakthrough Series methodology. Each team was to audit the national preventive bundles, using a Kamishibai card, and drive changes using plan–do–study–act cycles. Before the project, teams reported their 6-month baseline incidence levels. The main outcome was the incidence of infection. The secondary outcome was the proportion of teams that achieved a ≥50.0% reduction in incidence. The number of infections, deaths and bed-days potentially prevented, and costs saved during the project were estimated, along with the potential gains in the future. Results: Incidence rate for teams reporting at least 36 months decreased 47.6% in CAUTI (4.8 to 2.5 infections/1000 device-days), 66.1% in CLABSI (1.5 to 0.5 infections/1000 device-days) and 50.0% in VAP (9.9 to 5.0 infections/1000 intubation-days). The proportion of teams achieving a reduction of at least 50% in infection incidence was 60.0%, 100% and 57.1%, respectively. Teams reporting ≥24 months may have prevented 465 HAI, 108 deaths, 4526 bed-days and saved 8,375,841 euros. In the future, the teams who reported for at least 36 months may avoid 150 cases, 36 deaths, 1538 bed-days and 2,693,546 euros, yearly. Conclusions: A national collaborative focused on evidence-based bundles may be effective in decreasing the incidence of CAUTI, CLABSI and VAP in adult intensive care units. Full article

To address the problems where the resistance coefficients of the two-stage brush seal porous medium model rely on experimental calibration and the resistance characteristics of each stage are difficult to distinguish, this paper proposes a method without experimental calibration for determining the porous medium resistance coefficients of two-stage brush seals. By combining the three-dimensional tube bundle model with porous medium theory and Hagen–Poiseuille flow theory, the viscous and inertial resistance coefficients of each stage were derived. Two-stage brush seal specimens with three backing plate protection heights were manufactured, and a leakage flow experimental setup was constructed to verify the proposed method. Differences in resistance coefficients between the two stages and the effect of backing plate protection height on resistance coefficients were investigated. Results show that the calculated leakage rates from the porous medium model agree well with experimental data, verifying the accuracy of the proposed solution method. In the two-stage brush seal, both the viscous and inertial resistance coefficients of the second stage are significantly higher than those of the first stage. This study provides an effective method for calculating the porous medium resistance coefficients for each stage of two-stage brush seals and for predicting their leakage characteristics. Full article