High Load Research Articles

Hydrogen Use in a Dual-Fuel Compression Ignition Engine with Alternative Biofuels

Recent progress has been made towards decarbonisation of transport, which accounts for one quarter of global carbon dioxide emissions. For the short to medium term, new European Union (EU) and national energy and climate plans agree on a strategy based on the combination of increasing shares of electric vehicles with the promotion of sustainable fuels, especially if produced from residual feedstock and routes with low or zero net carbon emission. Hydrogen stands out among these fuels for its unique properties. This work analyses the potential of using hydrogen in a dual-fuel, compression ignition (CI) engine running with three diesel-like fuels (conventional fossil diesel, advanced biodiesel (BD) and hydrotreated vegetable oil (HVO)) and different hydrogen energy substitution ratios. The results were confronted with conventional diesel operation, revealing that dual-fuel combustion with hydrogen demands higher exhaust gas recirculation (EGR) rates and more advance combustion, leading to a remarked reduction of NOx emission at the expense of a penalty in energy consumption due mainly to unburnt hydrogen and wall heat losses. Unreacted hydrogen was ameliorated at high load. At low load, the use of BD dual combustion permitted higher hydrogen substitution ratios and higher efficiencies than diesel and HVO.

Development and testing of a four-item version of the physical resilience instrument for older adults (PRIFOR-4)

The 16-item Physical Resilience Instrument for Older Adults (PRIFOR) has good clinimetric properties; however, a shortened PRIFOR would greatly enhance physical resilience measurements in clinical settings. The current analysis aimed to reduce the number of PRIFOR while maintaining its clinimetric properties, emphasizing on its factor structure and convergent validity. A longitudinal study was conducted among 863 patients aged 65 years or older. Four PRIFOR items with high factor loadings were selected to generate the short version of PRIFOR (PRIFOR-4). The PRIFOR-4 was found to have a unidimensional structure (comparative fit index = 0.999; Tucker-Lewis index = 0.998 in the confirmatory factor analysis results) with good convergent validity with various external measures (absolute r = 0.109–0.597; p-values<0.01). Because the PRIFOR-4 contains only four items, the completion time for the respondents reduced three fourths from the original PRIFOR, which may have a marked reduction in the response burden. The PRIFOR-4 is thus an easy-to-use measurement that saves time for healthcare professionals in clinical practice.

Scaling to practical pouch cell supercapacitor: Electrodes by electrophoretic deposition

The scale-up of supercapacitors by electrophoretic deposition (EPD) from coin cell to pouch cell with commercially relevant mass loadings and thicknesses is reported. The use of EPD in electrode fabrication mainly reduces the interfacial resistance and increases the mechanical flexibility of the electrodes. The cycling performance or conversion efficiency can also be improved due to the highly porous EPD coatings. An exemplary investigation of activated carbon (AC) electrodes with an electrolyte comprising of tetraethylammonium tetrafluoroborate in acetonitrile is carried out. According to the general literature, EPD of AC on metal substrates has not performed well for supercapacitor electrodes unless they were thinner and with lower mass loadings than commercial requirements. As a consequence, and to redress this research gap, all the electrodes prepared in this work demonstrate high mass loadings (8 mg cm−2) and practical layer thicknesses (125 µm) and contain polyvinylidene fluoride binders with electrically conductive carbon black particles. Research investigations include: (a) impact of EPD of AC onto small (10 cm2) and large areas (50 cm2) of aluminum foil current collectors, (b) scaling-up of coin to pouch cells, and (c) the preparation of electrode coatings on both sides of the current collector for the first time using EPD for pouch cell investigations. Our research learning shows the evidence of practical cell performance, including current loading (40 A g−1), tens of thousands of successive charge and discharge operation (150,000 cycles), power (30 kW kg−1) and energy densities (10 W h kg−1), capacitance (154 F g−1), capacitance retention (80%) and coulombic efficiency (relatively close to 100%). Based upon the success of the pouch cells investigated in this work, further research studies on the use of EPD for preparing energy storage electrodes for commercial cylindrical types of supercapacitors is envisaged.

Monitoring Within-Individual Dose-Response Relationships in Professional Soccer Players: The Importance of Fitness Level.

To (1)examine within-individual player dose-response associations between selected training-load measures and changes in aerobic fitness level via submaximal exercise heart rate (HRex%) and (2)measure the relationships between these dose-response associations with basal HRex% (to study the influence of fitness level on dose-response relationship). During an in-season phase, selected training-load measures including total minutes, total distance, mechanical work (the sum number of accelerations and decelerations > 3m2), high metabolic load distance, and Edwards' training impulse were collected via Global Positioning System and heart-rate sensors for analyzing accumulated load. A submaximal warm-up test was used repeatedly before and after 9 phases to elicit HRex% and track fitness changes at an individual level. Negative to positive extensive ranges of within-individual associations were found among players for different metrics (r = -.84 to .89). The relationship between pooled HRex% (basal fitness) and dose-response correlations showed inverse very large (r = -.71) and large (r = -.65) values for accumulated weekly minutes and distance. However, moderate values were found for all other measures (r = -.35 to -.42). Individual players show extensive different ranges of dose-response associations with training measures. The dose-response association is influenced by players' fitness level, and players with lower fitness levels show stronger inverse relationships with accumulated minutes and total distance.

Stabilizing high temperature operation and calendar life of LiNi0.5Mn1.5O4

Severe capacity degradation at high operating voltages and poor interphase stability at elevated temperature have thus far precluded the practical application of LiNi0.5Mn1.5O4 (LNMO) as a cathode material for lithium-ion batteries. Addressing these challenges through a combination of experimental and theoretical methods in this work, we demonstrate how a fluorinated carbonate electrolyte enables both high-voltage and high temperature operation by mitigating the traditional interfacial reactions observed in electrolytes with conventional carbonate solvents. Computational studies confirm the exceptional oxidation stability of fluorinated carbonate electrolyte which reduces deprotonation at high voltage. The mitigated deprotonation will then minimize the formation of HF acid which corrodes the LNMO surface and leads to phase transformation and poor interphases. With fluorinated carbonate electrolyte at elevated temperature, it was found on LNMO’s subsurface a reduced amount of Mn3O4 phase which can block Li+ transfer and result in drastic cell failure. Leveraging this approach, LNMO/graphite full cells with a high loading of 3.0 mAh/cm2 achieve excellent cycling stability, retaining ∼84 % of their initial capacity at room temperature (25 °C) after 200 cycles and ∼68 % after 100 cycles at 55 °C. This advanced electrolyte also shows promise for improving calendar life, retaining >30 % more capacity than the carbonate baseline after high temperature storage. These results indicate that electrolytes based on fluorinated carbonates are a promising strategy for overcoming the remaining challenges toward practical commercial application of LNMO.

Compression behaviour of self-compacting concrete under dynamic loading at different ages

Self-compacting concrete (SCC) is widely used in reinforced concrete buildings, owing to its ability to consolidate by weight and its lack of requirement for external vibration. Reinforced concrete buildings can be subjected to high strain rate loading during the early days of construction or in their service life. Thus, it is critical to understand the behaviour of concrete under high strain rate loadings at different ages. Minimal studies have previously focused on the early-age behaviour of concrete under high strain rates. This study tries to fill this gap. It focuses on the behaviour of M40 grade SCC under three levels of strain rate loading at ages of 1, 3, 7, 14 and 28 d. The split-Hopkinson pressure bar (SHPB) was used to test 45 SCC specimens of diameter 100 m and thickness 50 mm at high strain rates, ranging from 30 s−1 to 110 s−1, and the determined compressive strength, peak strain and elastic modulus results are compared with quasistatic test results of SCC specimens. The dynamic increase factor (DIF) determined in the SHPB experiment is compared with the CEB-fib code model. The results indicate that the DIF reduces as the concrete's strength and age increase.

Investigating Temperature-Dependent Microscopic Deformation in Tough and Self-Healing Hydrogel Using Time-Resolved USAXS.

Tough and self-healing hydrogels are typically sensitive to loading rates or temperatures due to the dynamic nature of noncovalent bonds. Understanding the structure evolution under varying loading conditions can provide valuable insights for developing new tough soft materials. In this study, polyampholyte (PA) hydrogel with a hierarchical structure is used as a model system. The evolution of the microscopic structure during loading is investigated under varied loading temperatures. By combining ultra-small angle X-ray scattering (USAXS) and Mooney-Rivlin analysis, it is elucidated that the deformation of bicontinuous hard/soft phase networks is closely correlated with the relaxation dynamics or strength of noncovalent bonds. At high loading temperatures, the gel is soft and ductile, and large affine deformation of the phase-separated networks is observed, correlated with the fast relaxation dynamics of noncovalent bonds. At low loading temperatures, the gel is stiff, and nonaffine deformation occurs from the onset of loading due to the substantial breaking of noncovalent bonds and limited chain mobility as well as weak adaptation of phase deformation to external stretch. This work provides an in-depth understanding of the relationship between structure and performance of tough and self-healing hydrogels.

An effective approach for reducing data redundancy in multi-agent system communication

The redundancy of the data is an active research topic. While an agent works in a multi-agent system, the number of messages between them increases. This is due to the fact that the functionalities data depends on other agents in terms of functional requirements. Typically, only one agent in a multi-agent system is responsible for accessing a database instead of replicating the database on each agent. A database is stored on multiple agents rather than a single agent to avoid a single point of failure. In this approach, the system has a higher load because one agent is responsible for all agent queries and must send duplicate messages to multiple agents, resulting in redundant data. In this research, we present Multi-Agent System for Commodity Data (MASCD) framework, the multi-agent system based communication using the distributed hash system, to reduce data redundancy in multi-agent system communication. Our anticipated method demonstrated how we divided the database names and efficiently distributed data to each agent. The database splitting is based on manufacturer names or product names. We utilize a table based on prime numbers. Through the hash function, we ascertain the index of the agent granted access to the relevant data. Each agent is accountable for its data. We use a Distributed Hash Table for efficient querying that stores data as key-value pairs. Each agent maintains a Finger Table containing the next and previous nodes for agent communication purposes. Using FIPA messages, we demonstrated how an agent could interact optimally. In conclusion, we illustrate the application of the proposed approach through a case study of mobile phones and university information systems.

Fluorinated Surface Engineering Towards High‐Rate and Durable Potassium‐Ion Battery

AbstractSolid electrolyte interphase (SEI) crucially affects the rate performance and cycling lifespan, yet to date more extensive research is still needed in potassium‐ion batteries. We report an ultra‐thin and KF‐enriched SEI triggered by tuned fluorinated surface design in electrode. Our results reveal that fluorination engineering alters the interfacial chemical environment to facilitate inherited electronic conductivity, enhance adsorption ability of potassium, induce localized surface polarization to guide electrolyte decomposition behavior for SEI formation, and especially, enrich the KF crystals in SEI by self‐sacrifice from C−F bond cleavage. Hence, the regulated fluorinated electrode with generated ultra‐thin, uniform, and KF‐enriched SEI shows improved capacity of 439.3 mAh g−1 (3.82 mAh cm−2), boosted rate performance (202.3 mAh g−1 at 8.70 mA cm−2) and durable cycling performance (even under high loading of ~8.7 mg cm−2). We expect this practical engineering principle to open up new opportunities for upgrading the development of potassium‐ion batteries.

Fluorinated Surface Engineering towards High-rate and Durable Potassium-ion Battery.

Solid electrolyte interphase (SEI) crucially affects the rate performance and cycling lifespan, yet to date more extensive research is still needed in potassium-ion batteries. We report an ultra-thin and KF-enriched SEI triggered by tuned fluorinated surface design in electrode. Our results reveal that fluorination engineering alters the interfacial chemical environment to facilitate inherited electronic conductivity, enhance adsorption ability of potassium, induce localized surface polarization to guide electrolyte decomposition behavior for SEI formation, and especially, enrich the KF crystals in SEI by self-sacrifice from C-F bond cleavage. Hence, the regulated fluorinated electrode with generated ultra-thin, uniform, and KF-enriched SEI shows improved capacity of 439.3 mAh g-1 (3.82 mAh cm--2), boosted rate performance (202.3 mAh g-1 at 8.70 mA cm-2) and durable cycling performance (even under high loading of ~8.7 mg cm-2). We expect this practical engineering principle to open up new opportunities for upgrading the development of potassium-ion batteries.

Aqueous Zinc-Iodine Pouch Cells with Long Cycling Life and Low Self-Discharge.

Aqueous zinc batteries are practically promising for large-scale energy storage because of cost-effectiveness and safety. However, application is limited because of an absence of economical electrolytes to stabilize both the cathode and anode. Here, we report a facile method for advanced zinc-iodine batteries via addition of a trace imidazolium-based additive to a cost-effective zinc sulfate electrolyte, which bonds with polyiodides to boost anti-self-discharge performance and cycling stability. Additive aggregation at the cathode improves the rate capacity by boosting the I2 conversion kinetics. Also, the introduced additive enhances the reversibility of the zinc anode by adjusting Zn2+ deposition. The zinc-iodine pouch cell, therefore, exhibits industrial-level performance evidenced by a ∼99.98% Coulombic efficiency under ca. 0.4C, a significantly low self-discharge rate with 11.7% capacity loss per month, a long lifespan with 88.3% of initial capacity after 5000 cycles at a 68.3% zinc depth-of-discharge, and fast-charging of ca. 6.7C at a high active-mass loading >15 mg cm-2. Highly significant is that this self-discharge surpasses commercial nickel-metal hydride batteries and is comparable with commercial lead-acid batteries, together with the fact that the lifespan is over 10 times greater than reported works, and the fast-charging performance is better than commercial lithium-ion batteries.

Survival analysis of adult visceral leishmaniasis patients admitted to Metema Hospital, Metema, Ethiopia: a hospital-based cross-sectional study.

Visceral leishmaniasis (VL) is a neglected tropical disease that mostly affects the working class and impoverished segments of society, having a significant negative effect on the economic development of the affected nation. While anti-leishmanial medications lower mortality among VL patients, patients may still die or require more time to recover while receiving treatment. In this regard, there are limited studies in Ethiopia. This study aims to determine the time to recovery and its associated predictors among adult VL patients at Metema Hospital, Metema, Ethiopia. A hospital-based cross-sectional study was employed and the data were collected from patient's charts from September 2017 to September 2021. Data were entered and analysed using EpiData version 3.1, Stata version 14.2 and R version 3.4.0 statistical software. Kaplan-Meier survival curves and logrank tests were used to compare the survival time. The Cox proportional hazards model assumption and model fitness were checked and used to identify statistical association predictors in VL patients. The Cox proportional hazards model was fitted. The overall medium recovery time was 7d (minimum 4, maximum 14). The variables of nasal bleeding (adjusted hazard ratio [aHR] 0.44 [95% confidence interval {CI} 0.19 to 0.89]), no comorbidity (aHR 2.29 [95% CI 1.27 to 4.11]), relapse of VL (aHR 0.33 [95% CI 0.15 to 0.75]), low parasite load (aHR 2.58 [95% CI 1.48 to 4.51]) and ambulatory (aHR 3.26 [95% CI 2.45 to 6.53]) were significantly associated with time to recovery in VL patients. Patients with comorbidities, nasal bleeding, relapse of VL, bedridden and high parasite load should be treated and monitored carefully to recover quickly from their illness.

Chitin-derived hierarchical meso- and microporous carbon enables high-rate sulfur cathode of sodium-sulfur batteries.

Room temperature Na-S batteries are considered as a promising alternative energy storage system because of their abundant material resources and high theoretical energy density. However, the severe polysulfide shuttle effect and slow reaction kinetics hinder their practical application. Herein, a hierarchical meso- and microporous carbon with nitrogen self-doping (NSPC) is prepared using chitin as the carbon precursor and serves as a novel host to confine the sulfur (S⊂NSPC). An optimized structure of NSPC, including abundant graphite nanocrystals, large pore volume of 1.76 cm3 g-1, and large specific surface area of 2073 m2 g-1 is obtained at the carbonization temperature of 1000 °C. These merits contribute to significantly enhanced charge transfer and ion diffusion of the as-prepared S⊂NSPC-1000 cathode, which exhibits the outstanding sodium storage performance, including high reversible capacities of 1207 mAh g-1 at 0.1 C and 891 mAh g-1 at 2 C and stable cycling with a low capacity decay for 400 cycles at 1 C, among other S⊂NSPC cathodes and previously reported cathodes for Na-S batteries. This cathode can also afford stable cycling at a high sulfur loading.

Auxiliary osseous findings in fetlocks of non-racing sports horses with sagittal groove disease of the proximal phalanx on low-field magnetic resonance imaging.

Sagittal groove disease of the proximal phalanx in equine athletes is commonly considered a bone stress injury. Repetitive hyperextension of the fetlock under high load is thought to contribute to its development. Concurrent changes are often reported in the dorsal sagittal ridge of the third metacarpus/metatarsus (MC3/MT3). To describe the spectrum of associated osseous abnormalities that are present in the fetlock in a large group of horses diagnosed with sagittal groove disease on low-field magnetic resonance imaging (MRI). Retrospective, cross-sectional. MRI images of horses diagnosed with sagittal groove disease at Equitom Equine Clinic between March 2014 and March 2023 were evaluated using semi-quantitative grading schemes and a sagittal groove disease MRI classification system. MRIs of 132 limbs were evaluated, predominantly from warmbloods used for showjumping (n = 83) and dressage (n = 18). Osseous densification and bone oedema-like signal grades were higher in the dorsal sagittal ridge than palmarly/plantarly (p < 0.001 and p < 0.05, respectively). Grades of both osseous densification and bone oedema-like signal in the dorsal sagittal ridge did not significantly differ between the different sagittal groove disease MRI classifications (both p > 0.05). Inclusion based on original MRI reports, absence of control group, small numbers within some grading groups hindering statistical analyses. Findings support the aetiological theories of chronic bone-stress due to loaded fetlock hyperextension however the severity of osseous changes of the dorsal sagittal ridge does not appear to be associated with the severity of sagittal groove disease classification.

One-Pot Two-Stage Biocatalytic Cascade to Produce l-Phosphinothricin by Two Enantioselective Complementary Aminotransferases at High Substrate Loading via a Deracemization Process.

The bioderacemization of racemic phosphinothricin (D, L-PPT) is a promising route for the synthesis of l-phosphinothricin (L-PPT). However, the low activity and tolerance of wild-type enzymes restrict their industrial applications. Two stereocomplementary aminotransferases with high activity and substrate tolerance were identified in a metagenomic library, and a one-pot, two-stage artificial cascade biocatalytic system was developed to produce L-PPT through kinetic resolution and asymmetric amination. We observed that 500 mM D, L-PPT (100 g/L) could be converted into L-PPT with 94% final conversion and >99.9% enantiomeric excess (e.e.) within 24 h, with only 0.02 eq amino acceptor pyruvate and 1.2 eq amino donor l-aspartate required. The process could be scaled up to 10 L under sufficient oxygen and stirring. The superior catalytic performance of this system provides an eco-friendly and sustainable approach to the industrial deracemization of D, L-PPT to L-PPT.

Enhanced Atmospheric Water Harvesting Performance by Three-Dimensional Carbon Fiber Felt Structure.

Freshwater shortages and the uneven distribution of water resources are critical issues for economic development and human life, and collecting water vapor in the air is one of the important ways to alleviate these issues. In recent years, adsorption-based atmospheric water harvesting (AWH) techniques have received much attention, and the core difficulty in establishing an efficient system is to develop a highly efficient functional material for AWH. In this work, an AWH material was prepared consisting of carbon fiber felt as a three-dimensional skeleton and loaded with poly(vinyl alcohol) immobilized LiCl and graphite, as a water capture and release functional material. A 24 h water capture-3 h water release test was carried out at room temperature, showing excellent water collection ability of 0.907 g·g-1 of water at 30% relative humidity (RH) and 2.429 g·g-1 of water at 80% RH. Using a 2 h capture-2 h release cycling test, the sample demonstrated a stable water capture-release performance. An outdoor field test was conducted, showing water collection efficiencies of up to 60%. We believe that the carbon fiber felt can provide good mechanical properties and achieve a high mass loading of the functional materials, and the composite material has a simple manufacturing process and realizes energy saving and sustainable water harvesting.

Association of gestational hepatitis B virus infection and antiviral therapy with pregnancy outcomes: A retrospective study.

To explore the relationships between gestational hepatitis B virus (HBV) infection, antiviral therapy, and pregnancy outcomes. We retrospectively selected hepatitis B surface antigen (HBsAg)-positive pregnant women hospitalized for delivery at Fujian Medical University Affiliated Hospital from October 1, 2016 to October 1, 2020. The control group included randomly selected healthy pregnant women hospitalized for delivery during the same time. Overall, 1115 participants were enrolled and grouped into control (n = 380) and HBsAg-positive groups (n = 735), which were further divided into groups I (n = 407; low viral load), II (n = 207; high viral load without antiviral therapy), and III (n = 121; high viral load with antiviral therapy). Pregnant women with HBV were positively correlated with the incidence of intrahepatic cholestasis of pregnancy (ICP) (adjusted odds ratio [aOR] 5.1, 95% confidence interval [CI] 2.62-9.92, P < 0.001), neonatal jaundice (aOR 10.56, 95% CI 4.49-24.83, P < 0.001), and neonatal asphyxia (aOR 5.03, 95% CI 1.46-17.27, P = 0.01). Aspartate aminotransferase (AST) greater than the upper limit of normal (ULN) was an independent risk factor for increased ICP incidence (aOR 3.49, 95% CI 1.26-9.67, P = 0.019). Antiviral therapy considerably reduced HBV DNA and improved liver function. High viral load and antiviral therapy did not correlate significantly with adverse pregnancy outcomes (P < 0.05). Pregnant women with HBV have significantly elevated incidence of ICP, neonatal jaundice, and neonatal asphyxia not significantly correlated with viral load. AST greater than ULN independently increases the risk of ICP. Antiviral therapy effectively reduces viral replication and improves liver function without increasing the risk of adverse outcomes.

Blood flow restriction Exercise in the perioperative setting to Prevent loss of muscle mass in patients with pancreatic, biliary tract, and liver cancer: study protocol for the PREV-Ex randomized controlled trial

BackgroundPatients diagnosed with pancreatic, biliary tract, and liver cancer often suffer from a progressive loss of muscle mass. Given the considerable functional impairments in these patients, high musculoskeletal weight loads may not be well tolerated by all individuals. The use of blood-flow restricted resistance training (BFR-T) which only requires low training loads may allow for a faster recovery of muscle due to avoidance of high levels of mechanical muscle stress associated with high-load resistance exercise. This study aims to investigate whether BFR-T can prevent or slow down the loss of skeletal muscle mass and enhance the functional capacity and mental health of patients with pancreatic, biliary tract, and liver cancer.MethodsThe PREV-Ex exercise trial is a multicenter two-armed randomized controlled trial. Patients will be randomized to an exercise program consisting of home-based low-load BFR-T during a combined pre- and postoperative period for a total of 6–10 weeks (prehabilitation and rehabilitation), or to a control group. Protein supplementation will be given to both groups to ensure adequate protein intake. The primary outcomes, skeletal muscle thickness and muscle cross-sectional area, will be assessed by ultrasound. Secondary outcomes include the following: (i) muscle catabolism-related and inflammatory bio-markers (molecular characteristics will be assessed from a vastus lateralis biopsy and blood samples will be obtained from a sub-sample of patients); (ii) patient-reported outcome measures (self-reported fatigue, health-related quality of life, and nutritional status will be assessed through validated questionnaires); (iii) physical fitness/performance/activity (validated tests will be used to evaluate physical function, cardiorespiratory fitness and maximal isometric muscle strength. Physical activity and sedentary behavior (assessed using an activity monitor); (iv) clinical outcomes: hospitalization rates and blood status will be recorded from the patients’ medical records; (v) explorative outcomes of patients’ experience of the exercise program which will be evaluated using focus group/individual interviews.DiscussionIt is worthwhile to investigate new strategies that have the potential to counteract the deterioration of skeletal muscle mass, muscle function, strength, and physical function, all of which have debilitating consequences for patients with pancreatic, biliary tract, and liver cancer. The expected findings could improve prognosis, help patients stay independent for longer, and possibly reduce treatment-related costs.Trial registrationClinicalTrials.gov NCT05044065. Registered on September 14, 2021.

Influence of Tire-Enveloping Model Complexity on High-Frequency Simulations

ABSTRACT Race tires are subject to high speeds and high vertical loads during cornering. They are also subject to extreme stress when they are driven over high-frequency and low-amplitude curbs, often leading to tire failures. Research and development by D. C. Davis and P. W. A. Zegelaar has shown that when the tire moves over high-frequency, low-amplitude, and short-wavelength obstacles, it exhibits obstacle-enveloping properties. Tire response over such obstacles includes vertical force variation, longitudinal force variation, and rotational speed variation. Additionally, such road inputs excite tire belt dynamics that include high-frequency modes. Therefore, a single-contact-point model is no longer sufficient to predict tire response over such obstacles. To better capture the tire obstacle-enveloping behavior, advanced contact patch models such as the tandem-cam model by P. W. A. Zegelaar, the radial–interradial spring model by J. M. Badalmenti and G. R. Davis Jr., and the flexible ring model by S. Gong have been developed. To capture high-frequency tire belt dynamics, the rigid-ring model has been developed by P. W. A. Zegelaar. Previous work combines the rigid-ring model with the tandem-cam model to capture obstacle-enveloping behavior and tire belt dynamics up to 60–100 Hz. This paper presents a comparative study of different tire–road contact models to simulate high-frequency curbs typically found at racetracks. The curb profile of the Singes corner at the Paul Ricard racetrack is chosen for simulations as it is known to be extremely demanding on the tires, often causing failures. An advanced four-wheel model is used to simulate a race car at high speeds. Metrics to quantify the tire response over these high-frequency curbs are created and an investigation is conducted to quantify the influence of tire model complexity on the metrics.

Psychometric validation of a patient-reported experience measure for older adults attending the emergency department: the PREM-ED 65 study

IntroductionOptimising emergency department (ED) patient experience is vital to ensure care quality. However, there are few validated instruments to measure the experiences of specific patient groups, including older adults. We...