bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Validation of a Health Literacy Assessment Tool for COVID-19 Among Iranian Workers
Authors: Ghahremani Leila , Jafarpour Khadijeh , Ghodrati Kaveh , Nazari Mahin , Mokarami Hamidreza
Published: April 2024

Background:

The workforce is an organization's most important asset, and ensuring their health and safety is crucial for achieving the organization's mission and goals.

Objective:

The objective of this study was to design and validate a health literacy tool for COVID-19 among Iranian workers.

Methods:

This cross-sectional study involved a total of 201 participants. A personal information questionnaire was administered, and The Health Literacy Assessment (HLA) Tool was used to collect data specifically related to COVID-19. The HLA for COVID-19 was designed and developed, and the validity of the tool was evaluated through face, content, convergent, and construct validity analyses. To examine convergent validity, the Perceived Stress Scale was used. The reliability of the questionnaire was assessed using internal consistency measures, such as Cronbach's alpha coefficient.

Key Results:

The mean content validity index was 0.93, indicating high content validity. Confirmatory factor analysis results supported the five-dimensional structure of the tool. Significant correlations were found between the HLA for COVID-19 and perceived stress levels. The Cronbach's alpha coefficient for all items was 0.84, indicating high internal consistency.

Conclusion:

The HLA for COVID-19 is a concise, reliable tool for measuring health literacy related to COVID-19 among Iranian workers. Assessing COVID-19 health literacy in this population can be useful in evaluating the effectiveness of government officials, the media, and the medical and scientific community in providing necessary information. [

HLRP: Health Literacy Research and Practice
. 2024;8(2):e62–e68.

]
A post geographical vision of emergent micro cultural rural material world
Authors: Paniagua Angel
Published: April 2024

This paper analyzes the emergence of micro-cultural material worlds in marginal rural areas of Spain from the viewpoint of postmodern rural cultural geography. The methodology is qualitative and geo-ethnographic, based on the study of three cases that suggest a renewed relevance of place as cultural capital in the production and consumption pattern of new or renovated rural materialities. The main conclusions suggest that two sides characterized the renovated houses: externally linked with traditional spirit and style of the area and internal with an individual and cosmopolitan design These represent a new dialectic similarity/difference.
Research on characteristic quantity and intelligent classification prediction of metal magnetic memory detection signal
Authors: Guo Kai , Sun Chencan , Pan Wenjie , Fan Wenying , Zhang Hongsheng
Published: April 2024

Metal magnetic memory (MMM) is an innovative, nondestructive testing method. It can detect both stress concentrations and macroscopic defects. The three-dimensional force-magnetic coupling model was established by the ANSYS simulation software, the evolution process of different defect depths was studied in detail, and the change of the signal characteristic was analyzed. The results showed that the variation trend and amplitude characteristic of MMM signals resulted in obvious differences among different defect types. Meanwhile, the impacts caused by the defect parameters and the type are complex, which cannot be decoupled or calculated by a certain formula. The accuracy of the simulation data was verified by experiments. To solve the classification prediction problem in MMM detection, the signal peak and valley Hp-v, the signal width W, the gradient Ky, and the peak energy Hy were selected as characteristic parameters to evaluate different defect types according to the change in the signal waveform. Finally, using these vectors as the input variables, the radial basis function neural network (RBFNN) pre-classification test model was established to realize the classification recognition of pit defects, crack defects, and porosity defects. The results show that the accuracy of the training and test sets, and it is feasible to use this model to complete the intelligent classification of defects.
Novel fixed-time synchronization results of fractional-order fuzzy cellular neural networks with delays and interactions
Authors: Liu Jun , Deng Wenjing , Sun Shuqin , Shi Kaibo
Published: April 2024

This research investigated the fixed-time (FXT) synchronization of fractional-order fuzzy cellular neural networks (FCNNs) with delays and interactions based on an enhanced FXT stability theorem. By conceiving proper Lyapunov functions and applying inequality techniques, several sufficient conditions were obtained to vouch for the fixed-time synchronization (FXTS) of the discussed systems through two categories of control schemes. Moreover, in terms of another FXT stability theorem, different upper-bounding estimating formulas for settling time (ST) were given, and the distinctions between them were pointed out. Two examples were delivered at length to demonstrate the conclusions.
Populismo e Autoritarismo – Uma breve reflexão teórica
Authors: Costa Bruno Ferreira da
Published: April 2024

O século XXI caracteriza-se por um reaparecimento de soluções populistas em diversos espaços geográficos do mundo. Este fenómeno não adota um modelo único, sendo caracterizado por uma diversidade de medidas, regras, intensidades e caminhos, quanto à implementação de modelos de governação populistas. O atual contexto de medição da qualidade das democracias impele-nos a aprofundar o estudo em torno dos sistemas políticos e dos diversos elementos utilizados para aferir os regimes democráticos. Na literatura existente podemos encontrar diversos contributos sobre a evolução dos regimes políticos e sobre a análise do exercício do poder político, centrando-se o presente contributo em três tópicos: discussão sobre o conceito de “populismo” no quadro das democracias contemporâneas, enquadramento do populismo na dimensão plural de funcionamento das democracias e o progressivo espaço que o populismo tem conquistado no quadro de regimes políticos mais instáveis.
Transição Constitucional versus Transformação Constitucional: Angola e a necessidade de um novo paradigma fundacional
Authors: Melo Maria da Imaculada
Published: April 2024

Este texto sustenta que a transição constitucional equacionada para Angola da I para a II República (1991/92) e para a III República, não produziu a rutura subjacente a este instituto. Não se verificou o pressuposto essencial da transição constitucional no sentido de provocar uma rutura total com o regime em superação e de instalar outros fatores do poder e um regime diferente. Outrossim, verificou-se um processo de “transformação constitucional” que manteve vários traços fundamentais do anterior regime. Perante esta realidade, urgem reformas estruturais do Estado, em consonância com as necessidades da atualidade sociopolítica angolana, que aqui se apresentam, centradas essencialmente na importância de um eventual Parlamento bicamaral e na despartidarização do Estado por via da reforma do Direito e da Justiça.
La voie de l’institutrice brésilienne Maria Estephania de Macedo dans le milieu rural
Authors: Pereira Alisson José da Silva Esteves , Musial Gilvanice Barbosa da Silva
Published: April 2024

Dans cet article, nous analysons le cas de l’institutrice Maria Estephania de Macedo, de l’école du district de Vera Cruz/Pindahybas, municipalité de Sabará, Minas Gerais, Brésil, entre 1901 et 1911. À la fin du xixe siècle, l’État du Minas Gerais était confronté à une grave crise économique, politique et sociale ce qui a conduit, à l’adoption de la loi no 281 de 1899, qui a entraîné la suppression de 567 écoles rurales et de 91 écoles de district sous la responsabilité du gouvernement de l’État du Minas Gerais. Nous nous appuyons sur les concepts de stratégies et tactiques de Michel de Certeau afin d’aborder notre corpus documentaire. Nous pensons que tout le processus scolaire organisé par cette institutrice a été fondamental pour que l’école puisse continuer à opérer malgré un contexte complexe qui menaçait le droit à l’éducation publique en milieu rural.
Important Aspects Influencing the Dynamic Parameters of Slender Pedestrian Bridges Formed by Stress Ribbon Structure
Authors: Kolacek Jan , Necas Radim , Velesik Marek
Published: April 2024

The monitoring of dynamic parameters of slender bridge structures is becoming of particular interest in terms of their possible use in determining their structural condition, or possibly as one of the parameters for their long-term monitoring. The method for monitoring dynamic parameters is relatively new and practically unexplored. First of all, it is necessary to find out with certainty how the dynamic parameters of slender bridge structures change, for example, with changes in temperature, the magnitude of the prestressing force, or how they change with changes in discontinuous mass (e.g. overlaying or stripping of pavement layers). The paper summarizes the important aspects that can affect the modal parameters - natural frequencies and their shapes. The above listed influences and their impact on the structure were investigated on real structures formed by stress ribbon.
Mixture Design Identification of Admissible Tannery Sludge Incorporation in Fired Bricks
Authors: Ghrairi Armia , Ajam Lassaad , Limam Oualid
Published: April 2024

Pollution problems caused by industrial production of leather tanneries are an important environmental issue. In the present paper we propose to study effects of tannery sludge (TS) addition in manufactured clay bricks applying a mixture design formed by different proportions of four components: Clay, two types of sand and TS. The analysis leads to an optimal practical mixture of around 10% of TS, 20% of sand and 70% of clay and this to remain with an acceptable aspect, an admissible water absorption below 15%, an admissible total shrinkage (drying and after fire) lower than 8%, a tensile strength higher than 5MPa and a thermal conductivity of 0.93 Wm-1K-1, 15% lower than the reference mixture with 0% of TS. Experimental results indicate that a temperature cycle firing up to 950°C can lead to higher tensile strength and lower water absorption compared to a cycle that reaches only 850°C. Furthermore, incorporating (TS) in the fired brick manufacturing process can lead to significant energy saving. Additionally, it was observed that a moderate inclusion of TS can enhance evaporation process. Keywords : Mixture design, Tannery Sludge (TS); Clay bricks ; Evaporation ; Strength; Water absorption; Shrinkage; Leaching; Energy.
Experimental Study of Friction Factor Reduction by Adding Aloe Vera Gel in Pipes Transporting Dams Sediments
Authors: Miloud Moudjeb , Larbi Hammadi , Ali Nemdili
Published: April 2024

The phenomenon of siltation represents an enormous risk for the lifespan and safety of dams, and there are several methods for evacuating sediments, of which the hydraulic dredging technique is the most widely used. But during this operation there are load loss exists so it is necessary to find solutions to reduce it. The purpose of this work is to use the Aloe Vera gel as a load loss reducer during hydraulic dredging of dams. To carry out this study, a rheumatic characterization of dams sediments and dams sediments - Aloe Vera gel mixtures was carried out using a torque controlled rheometer (Discovery Hybrid Rheometer DHR2 from TA instrument) and a hydraulic study carried out on a closed-circuit installation comprising three pipes of different diameters and lengths, supplied by a centrifugal pump driven by a variable speed Diesel engine. The experimental work was carried in pipe of diameter D1=36.16 mm and length L1 = 12.24 m with the quantity of Aloe Vera 2 to 10 wt% and different speed of rotation of pump. The flow curves as a function of dose of Aloe Vera added to dam sediments were analysed by the Casson model. The calibration of installation has been fitted by the Blasius equation. The addition of Aloe Vera gel with a quantity range between 2 and 10 wt% to dams sediments of 40 wt% and 45 wt% induces an decrease in the yield stress and the viscosity infinite of dams sediments. The study also demonstrated that adding of 6 wt% of sodium tripolyphosphate to 40 wt% and 45 wt% dam sediments decreased the friction factor by 75% and 85% respectively
Response Surface Optimization of Rice and Guinea Corn Husk Ash Blended Concrete
Authors: Odeyemi Samson Olalekan , Omoniyi Ahmed Olatunbosun , Adisa Michael Oluwasegun , Abdulwahab Rasheed , Akinpelu Mutiu Adelodun
Published: April 2024

Concrete, a fundamental construction material, consists of aggregates, water, cement, and additives. Unfortunately, the large-scale production of cement is a major contributor to carbon dioxide (CO2) emissions, primarily from the manufacturing process and the consumption of fossil fuels. This not only incurs environmental costs associated with global warming but also depletes vital limestone deposits. To mitigate these issues, this study aims to explore the optimal utilization of Guinea Corn Husk Ash (GCHA) and Rice Husk Ash (RHA) in concrete. This research investigated the chemical properties of GCHA and RHA, and their impact on the compressive and split-tensile strengths of concrete when integrated in various proportions. The study reveals that both GCHA and RHA meet the minimum oxide content requirement of 70% set by ASTM C618, with silicon dioxide (SiO2) as the predominant oxide. Increasing the content of RHA and GCHA from 5% to 10% improves the concrete's compressive and split-tensile strengths after curing for 56 days. Optimization results indicate that the ideal mix consists of 10% GCHA, 8.5% RHA, and 82.5% cement, yielding a compressive and split tensile strength of 31.34 N/mm² and 3.07 N/mm² respectively. This study thus offers a promising solution for sustainable concrete production by reducing the environmental footprint of cement while enhancing material properties and promoting an eco-friendlier approach to construction. Keywords: Concrete, Guinea Corn Husk Ash, Rice Husk Ash, Compressive Strength, Split-Tensile Strength
Numerical Simulation Study on the Effect of Resistance Microstructure on Blood Flow Resistance
Authors: Wang Wen Ting , Gu Yun Qing , Yu Ling Zhi , Yin Zhuo Fan , Li Zhou , Wu Deng Hao , Mou Jie Gang , Zheng Shui Hua , Zhou Hui Jie
Published: April 2024

The use of bionic drag-reducing microstructures in artificial blood vessels can effectively reduce their resistance to blood flow. The characteristics of the blood vessel are analysed and simplified, and the resistance reduction effects of three bionic microstructure models, namely V-shaped, rectangular and semi-circular, are compared and analysed by numerical simulations, and the resistance reduction effects of the three groove structures in the tubular model are verified. The results show that the V-shaped groove structure occupies a smaller volume compared to the rectangular and semi-circular structures of the same size, has a significant drag reduction effect, is highly achievable and stable, and is the best choice as a drag reduction microstructure for artificial blood vessels. In addition, the wall shear stresses of the V-groove structure were further analysed to verify the shear effect of this microstructure in artificial blood vessels and to reveal the shear mechanism of the V-groove microstructure.
The microstructure and the behaviour of low organic clayey soils in Sri Lanka
Authors: Wang Y. , Vidurapriya D. , Qin X. , Thilakasiri S.
Published: April 2024

Numerous studies focus on investigating organic soils with high organic content. However, only a limited amount of literature discusses the properties and behaviour of low organic content soils. Sri Lankan organic soil is an excellent example of a low organic content soil, demonstrating different behaviour from highly organic fibrous soil. Scanning electron microscope (SEM) images of Sri Lankan organic soil were studied to determine the reasons for these observed variations. Sri Lankan organic soils were observed to consist of highly decomposed organic matter in an amorphous state with higher proportions of mineral matter. The microstructure characteristics observed through SEM images mostly explained the variation of properties and behaviour of the Sri Lankan organic soil in contrast to highly organic fibrous soil. Correlations were also derived between properties of Sri Lankan organic soil and compared with similar relationships derived from other geological conditions. While some correlations derived in this study closely follow the relationships for other organic soils with similar microstructure characteristics, the acidity of the deposit resulted in different behaviour of a few correlations. This study improves the current knowledge of the effect of microstructure characteristics on the properties and behaviour of Sri Lankan low-organic clayey soils, which otherwise primarily depend on theories for highly organic peaty soils. Furthermore, the correlations derived and validated for low organic soils can be utilized in any organic clay deposit with similar microstructure characteristics.
Comparison of methods for handling outliers in Cox regression model
Authors: Alkan N. , Pardo M.C. , Alkan B.B.
Published: April 2024

The Cox regression analysis is used to determine the relationship between a dependent variable and covariates in survival analysis involving censored data. The proportional hazards assumption is one of the most important assumptions of Cox regression. Outliers may have a strong influence on the Cox regression model’s parameter estimates and lead to violation of the proportional hazard assumption. Therefore, having outliers in the data set is a problem for researchers. In this case, robust estimations are commonly used to infer the parameters in a more robust way. However, we explore a new approach consisting of considering an outlier as missing data and replacing it by the multiple imputation method. The aim of this study is to compare these two methods through simulation. Furthermore, an analysis of a lung cancer data set is considered for illustration. According to the results of the study carried out based on simulated data sets and a real data set, the multiple imputation method, which is a missing data analysis method, solves the problem of outliers better than the robust estimation method, as the outcome is closer to the results obtained through original data.
Skeletal point analysis to determine the accuracy of forehand smash shots played by badminton players
Authors: Krishnaram N. , Ahamed J. , Sathyamoorthy N. , Sandaruwan K.D. , Athapaththu A.M.K.B.
Published: April 2024

This study aims to address the scarcity of scientific research on badminton performance analysis, specifically the accuracy of forehand smash shots. The authors propose the use of a skeletal coordinates-based technology to analyze a badminton player’s biomechanics. To achieve this, specific techniques, such as formulating a quantitative description of badminton smash biomechanics based on the available literature, collecting video footage of badminton rallies and processing them using a MediaPipe-powered Python program, were followed. Three main approaches were considered for the analysis, defining a dynamic mathematical model, creating a player-to-player comparison model, and developing a machinelearning model. Preliminary results suggest that the use of three-dimensional points in comparison to two-dimensional points provides more accuracy in detecting the angle between three skeletal points from any camera perspective. This research also proposes a novel approach to compare two players and evaluate their skills based on a set of key parameters. The study explores the integration of machine learning algorithms to classify and predict player performance accurately. All three proposed methods enable coaches and players to identify and improve upon their weaknesses, enhancing their overall performance, as these findings have the potential to reduce subjectivity in measuring shot accuracy during training and to provide players with a more objective means of evaluating their performance. The proposed methodology and results contribute to a better understanding of badminton biomechanics and have implications for future research in this field.
Typification of the name Cistus × skanbergii Lojac., a rare rockrose extinct in its type locality
Authors: Pasta Salvatore , Troia Angelo
Published: April 2024

In 1885 Lojacono-Pojero described Cistus skanbergi, also known as the dwarf pink rockrose, from the Island of Lampedusa (Sicily, Italy). Despite becoming extinct in its type locality and being very rare in the Mediterranean Basin, during the last decades the plant corresponding to this name, a natural hybrid between C. parviflorus Lam. and C. monspeliensis L., has been successfully cultivated and introduced worldwide for ornamental purposes. The search carried out in several European herbaria allowed to select as lectotype a specimen collected by Lojacono-Pojero and kept at the herbarium of Kew, to detect other isolectotypes, kept in the herbaria of Geneva and Palermo, and to detect another syntype corresponding to a specimen collected by Gussone and currently kept at the herbarium of Palermo.
First description of the breeding biology and behaviour of the near threatened northern sooty woodpecker Mulleripicus funebris (Valenciennes 1826) (Piciformes: Picidae) in Luzon Island, Philippines
Authors: Gicaraya Vince Angelo G. , Española Carmela P.
Published: April 2024

Although generally regarded as keystone species within forest communities, woodpeckers (Picidae) remain understudied in the Philippines. We describe for the first time the breeding biology and behaviour of the IUCN Near Threatened northern sooty woodpecker Mulleripicus funebris based on observations from a single active nest found in a standing dead Parkia timoriana tree at the Subic Watershed Forest Reserve, Zambales, Luzon, Philippines. The nest was observed from late February to May 2022 for a total of 63.7 hours. The cavity was 16.4 m from the ground and had opening dimensions (L x W) of 9.0 x 8.0 cm and a depth of 37.0 cm. Breeding of M. funebris lasted ≈76-83 days from nest excavation (≈27 days) to fledging. The brood size was two. Both parents were involved in nest building and chick-rearing activities. The male M. funebris contributed more hours during nest building and diurnal incubation whereas the female dominated feeding of nestlings and nest sanitation during the time of fledging. We recommend the retention of standing dead trees as nesting sites for woodpeckers and already existing holes for other cavity-nesting fauna.
Enhanced Safety of Heavy-Duty Vehicles on Highways through Automatic Speed Enforcement – A Simulation Study
Authors: Shiledar Ankur , Sujan Vivek , Siekmann Adam , Yuan Jinghui
Published: April 2024

Highway safety remains a significant concern, especially in mixed traffic scenarios involving heavy-duty vehicles (HDV) and smaller passenger cars. The vulnerability of HDVs following closely behind smaller cars is evident in incidents involving the lead vehicle, potentially leading to catastrophic rear-end collisions. This paper explores how automatic speed enforcement systems, using speed cameras, can mitigate risks for HDVs in such critical situations. While historical crash data consistently demonstrates the reduction of accidents near speed cameras, this paper goes beyond the conventional notion of crash occurrence reduction. Instead, it investigates the profound impact of driver behavior changes within desired travel speed distribution, especially around speed cameras, and their contribution to the safety of trailing vehicles, with a specific focus on heavy-duty trucks in accident-prone scenarios. To conduct this analysis, we utilize SUMO, an open-source microscopic traffic simulator, enabling realistic simulations of real-world driving behaviors with and without speed cameras. The simulations also consider empirical distributions of desired headway gaps and reaction times exhibited by human drivers. This study offers a fresh perspective on highway safety by examining how the influence of automatic speed enforcement systems on driver behavior enhances the safety of HDV when faced with challenging situations. By shedding light on these dynamics, we contribute valuable insights to the ongoing research efforts on using technology to create safer roadways, ultimately promoting safer coexistence between heavy-duty and passenger vehicles.
Fully Retractable Easy Access Spare Wheel Carrier Mechanism for Commercial Vehicles
Authors: Bonde Devendra , Upkare Piyush Pradip , Verma Rubal
Published: April 2024

The new idea discussed in this paper pertains to the carrier mechanism for spare wheels in heavy commercial vehicles. Typically, these vehicles are equipped with a spare wheel carrier featuring a rope mechanism for loading and unloading the spare wheel. The conventional placement of this system is on the side of the frame/chassis or within the limits of the side member. However, the tire-changing process in this system is often arduous, time-consuming, and requires significant effort. The proposed invention addresses these challenges by repositioning the spare wheel to a vertical orientation, facilitating easier access to its bolts and simplifying the removal process from the mountings. Furthermore, the innovation incorporates a three-way actuation system (Air Actuated, Electric motor-driven, or Hydraulic cylinder actuated mechanisms), thereby reducing the need for manual effort and enhancing driver comfort. The advantages of this invention over traditional carrier mechanisms include no reduction in cargo space, applicability to various truck configurations, user-friendly operation, and reduced time consumption. The linkage design is optimized to ensure an optimal distance between the wheels, propeller shaft, cargo body, and the ground plane during the loading or unloading of the tire. This novel mechanism not only streamlines the design and operation but also minimizes the effort and time required to remove a spare tire.
Effect of local ductility on crash performance of automotive structures considering press forming strain of advanced high strength steels
Authors: Sato Kentaro , Sakaidani Tomohiro , Komine Shinsuke , Wang Fangyi , Nakagaito Tatsuya
Published: April 2024

A fundamental study on the ductility of high strength steels in crash deformation is carried out to investigate the effect of the local ductility of various materials on automobile crashworthiness, considering the prestrain induced by press forming in the manufacturing process. In this study, a newly developed 980 MPa-grade steels [1], ‘jetQTM’, is investigated to clarify its advantage in term of crashworthiness in comparison with the conventional DP (Dual Phase) and TRIP steels.

Quasi-static axial crushing tests are performed to evaluate the crashworthiness of the different types of steel. Based on the experimental results, the effect of the local ductility of high-strength steel on the risk of material fracture is discussed.

In this paper, a new bending test method, orthogonally reverse bending, (ORB), is proposed to simulate the fracture that occurs during crash deformation considering press-forming strain. The test method is developed using a combination of the V-bending process and the tight radius bending method (based on VDA 238-100). The V-bending process is used to induce the pre-strain in the test sample, simulating the strain caused by press-forming, and the second bending process is performed to evaluate the fracture angle and local ductility of the high strength steel after the press-forming process. The proposed ORB method shows that the local ductility of TRIP steel is decreased by the press-forming due to transformation of the microstructure, while jetQ steel displays higher local ductility even after press-forming.

A numerical simulation model is also developed to understand the fracture behavior in the ORB process. The simulation shows that fracture strain occurs in the local bending area with prestrain by the V-bending process.

Finally, the applicability of the developed high strength steel to automobile body structures to realized light-weight body structures is discussed.
A Special User Shell Element for Coarse Mesh and High-Fidelity Fatigue Modeling of Spot-Welded Structures
Authors: Zhang Lunyu , Wu Shengjia , Dong Pingsha
Published: April 2024

A special spot weld element (SWE) is presented for simplified representation of spot joints in complex structures for structural durability evaluation using the mesh-insensitive structural stress method. The SWE is formulated using rigorous linear four-node Mindlin shell elements with consideration of weld region kinematic constraints and force/moments equilibrium conditions. The SWEs are capable of capturing all major deformation modes around weld region such that rather coarse finite element mesh can be used in durability modeling of complex vehicle structures without losing any accuracy. With the SWEs, all relevant traction structural stress components around a spot weld nugget can be fully captured in a mesh-insensitive manner for evaluation of multiaxial fatigue failure. For validation purposes, a set of spot-welded lab test specimens has been analyzed for demonstrating the mesh-sensitivity of structural stress computation and fatigue test data transferability, e.g., from lap-shear to coach-peel. Excellent results have been obtained.
Spectrum-Based Method for Fatigue Damage under Excitation of Sinusoidal Sweeps for Automotive Systems
Authors: Yang Zane , Zhou Lin
Published: April 2024

Vibration from a mechanical system not only produces unwanted noises annoying to people around, but also runs a risk of fatigue failure that would actually hinder its functionality. There are several forms of vibration depending on the sources of excitation forms. Mechanical systems with rotating components can be subjected to sinusoidal excitation due to the fact the center of mass is not perfectly aligned with the rotating axis. If the rotating speed is strictly ramping up or ramping down, this can create an excitation whose frequency is changing with time in a frequency range corresponding to the speeds swept. Compared with a single sinusoidal excitation, the issue with fatigue at swept sinusoidal excitation, is that as it sweeps through a wide frequency range, some swept frequencies will definitely coincide with the natural frequencies of the system. Certainly, the stress response exactly at the resonant frequency becomes the highest and could account for a lot of fatigue damage. However, the stress in the vicinity of that resonance frequency could also contribute to the accumulated damage, depending on how long the system is exposed to the vibration there. Hence, only using the stress magnitude at the resonance to evaluate the durability is not adequate. The purpose of this work is to present a spectrum-based approach to calculate the cumulative fatigue damage as the stress is oscillating around its means with gradually increased or decreased frequency. The fatigue prediction is based on the stress spectrum obtained from a steady-state solution to a linear vibration system at each individual frequency. The fatigue damage spectrum is derived from the stress spectrum, along with a sweeping mode for the excitation frequency. Two of the commonly-used sweep modes (i.e. logarithmic and linear sweeping modes) are studied for an automotive component and their difference in the effect on the damage results are discussed in detail, through an example of an automotive component. In this work, it will be demonstrated how to choose sine sweeping rate such that the steady-state solution is guaranteed and the premise of this spectral method for fatigue is still valid.
Introduction of the eGTU – An Electric Version of the Generic Truck Utility Aerodynamic Research Model
Authors: Howard Kevin , Chen Sheng , Dobronsky Sayan , Kochanek Zachary , Skinner Shaun
Published: April 2024

Common aerodynamic research models have been used in aerodynamic research throughout the years to assist with the development and correlation of new testing and numerical techniques, in addition to being excellent tools for gathering fundamental knowledge about the physics around the vehicle. The generic truck utility (GTU) was introduced by Woodiga et al. [1] in 2020 following successful adoption of the DrivAer (Heft et al. [2]) by the automotive aerodynamics community with the goal to capture the unique flow fields created by pickups and large SUVs. To date, several studies have been presented on the GTU (Howard et. al 2021 [3], Gleason, Eugen 2022 [4]), however, with the increasing prevalence of electric vehicles (EVs), the authors have created additional GTU configurations to emulate an EV-style underbody for the GTU.

The existing GTU has the flexibility to independently vary the cab and box lengths, plus a rear cap with three different backlight angles to model SUVs, however, the authors set out to model underbody geometry commonly found on EVs by creating separate underbody sections (belly pan, motor shield, battery shield and diffuser) and introduce modularity with the possibility for use as variables in future studies. Furthermore, a wheel and tire change is also completed and shared to highlight the sensitivity with the new underbody. Herein, the authors will build on the GTU capabilities by presenting the new underbody geometry and share initial wind tunnel and CFD results. Experimental testing for the eGTU was conducted at Ford’s Rolling-Road Wind Tunnel (RRWT) facility, while CFD simulations were conducted with an Open Source based Navier-Stokes solver.
Vehicle Drop Test Correlation for Two-Wheeler (Motorcycle) Using Multibody Simulation
Authors: Kaka Vaibhav , Jain Arvind
Published: April 2024

Off-roading is the scenario of driving a vehicle on unpaved surfaces such as sand, gravel, riverbeds, rocks, and other natural terrain. Vehicle designed for that purpose requires jumping from height due to uneven surfaces/patches. This also requires them to sustain a high amount of loads acting upon them on impact. Thus, off-roading vehicles should not only provide intended vehicle dynamics performance but at the same time should be durable as well.

Drop test which is done in a controlled environment is a widely used method to validate the durability of vehicle in such scenarios wherein the vehicle is dropped from a certain predefined height.

In Multibody dynamics simulation, drop test was replicated and acceleration data computed at different locations in the vehicle were correlated with actual physical test data. Correlation was done for different drop heights. This paper presents relevant details of the virtual vehicle modeling, loadcase, test data & subsequent correlation. This correlation helps in building the simulation robustness which eventually helps improve design so as to be capable of overcoming such practical scenarios.
A Holistic Approach to Next-Generation Polymer Composite Pickup Bed Development and Prototyping
Authors: Nummy Amanda
Published: April 2024

As we move toward electrification in future mobility, weight and cost reduction continue to be priorities in vehicle development. This has led to continued interest in advanced molding processes and holistic design to enable polymer materials for demanding structural applications such as pickup truck beds. In addition to performance, it is necessary to continue to improve styling, functionality, quality, and sustainability to exceed customer expectations in a competitive market. To support development of a lightweight truck bed design, a cross-functional team objectively explored the latest materials and manufacturing technologies relevant to this application. In Phase 1 of this work, the team considered a variety of alternatives for each functional area of the bed, including thermoplastic and thermoset materials with a range of processing technologies. Several initial design concepts and respective material cards were generated to capture the broadest set of materials and technologies, and preliminary simulations were run, showing that the concepts were feasible to optimize both cost and weight while meeting performance criteria. For Phase 2, the team selected the most promising design concept to move forward with detailed design and simulation, supported by novel material-level testing. Prototype tooling was fabricated, and several variations of lightweight fiber-reinforced composite parts were molded. Part testing achieved equivalent or improved results in mechanical performance relative to the incumbent design, and the team also gained insights into opportunities for optimization in the next steps, scaling up to demonstrate production capability. The successful correlation of physical testing to simulation results can further support the development of validation tools for future polymer composite designs and additional components. This work demonstrates that by taking a holistic approach to polymer composite structure development, performance targets can be met with innovative design and material selection, while cost and weight are balanced and optimized across the system.
An Assessment of the Tesla Model 3's Forward Collision Warning and Automatic Emergency Braking Systems against a Stationary Pedestrian Target
Authors: Harrington Shawn , Nagarajan Sundar Raman , Lau James
Published: April 2024

A total of 93 tests were conducted in daytime conditions to evaluate the effect on the Time to Collision (TTC), emergency braking, and avoidance rates of the Forward Collision Warning (FCW) and Automatic Emergency Braking (AEB) provided by a 2022 Tesla Model 3 against a 4ActivePA adult static pedestrian target. Variables that were evaluated included the vehicle speed on approach, pedestrian offsets, pedestrian clothing, and user-selected FCW settings. As a part of the Tesla’s Collision Avoidance AssistTM, these user-selected FCW settings change the timing of the issuance of the visual and/or audible warning provided. This testing evaluated the Tesla at speeds of 25 and 35 miles per hour (mph) versus a stationary pedestrian target in early, medium, and late FCW settings. Testing was also conducted with a 50% pedestrian offset and 75% offset conditions relative to the right side of the Tesla. The pedestrian target was clothed with and without a reflective safety vest to account for different conspicuity during the testing. The TTC at FCW and AEB, emergency braking deceleration and the avoidance rates were compared between different settings and test parameters. The test data was also compared against the IIHS pedestrian tests at different speeds and scenarios.
Wheel Air Drag Prediction Technique Using WAD Parameter
Authors: Kim Untae , Hwang Gyeongmin , Junsik Shin , Han Jeongmin , Park Sangmyun , Park Sanghyun
Published: April 2024

Wheel drag is generally known to be proportional to the wheel opening area. However, predicting wheel drag through opening area is still very difficult and inaccurate because there are many other factors that affect wheel drag. To more accurately and effectively predict wheel drag in the early styling design stage, we introduced the wheel average depth (WAD) parameter and developed S/W to calculate WAD. As a result of analyzing the correlation between WAD and wheel drag for HKMC's mass-produced wheels, the R2 value was greatly improved compared to the correlation between the existing wheel opening area and wheel drag, and the prediction accuracy was doubled.
Integrated Chassis Control for Energy-Efficient Operation of a 2WD Battery-Electric Vehicle with In-Wheel Propulsion
Authors: Heydrich Marius , Mitsching Thomas , Gramstat Sebastian , Lenz Matthias , Ivanov Valentin
Published: April 2024

Battery-electric vehicles (BEVs) require new chassis components, which are realized as mechatronic systems mainly and support more and more by-wire functionality. Besides better controllability, it eases the implementation of integrated control strategies to combine different domains of vehicle dynamics. Especially powertrain layouts based on electric in-wheel machines (IWMs) require such an integrated approach to unfold their full potential.

The present study describes an integrated, longitudinal vehicle dynamics control strategy for a battery electric sport utility vehicle (SUV) with an electric rear axle based on in-wheel propulsion. Especially the influence of electronic brake force distribution (EBD) and torque blending control on the overall performance are discussed and demonstrated through experiments and driving cycles on public road and benchmarked to results of previous studies derived from [1]. It is shown that the approach improves energy efficiency and energy recovery potential by nearly ten per cent.
Active Collision Avoidance System for E-Scooters in Pedestrian Environment
Authors: Yan Xuke , Shen Dan
Published: April 2024

In the dense fabric of urban areas, electric scooters have rapidly become a preferred mode of transportation. As they cater to modern mobility demands, they present significant safety challenges, especially when interacting with pedestrians. In general, e-scooters are suggested to be ridden in bike lanes/sidewalks or share the road with cars at the maximum speed of about 15-20 mph, which is more flexible and much faster than pedestrians and bicyclists. Accurate prediction of pedestrian movement, coupled with assistant motion control of scooters, is essential in minimizing collision risks and seamlessly integrating scooters in areas dense with pedestrians. Addressing these safety concerns, our research introduces a novel e-Scooter collision avoidance system (eCAS) with a method for predicting pedestrian trajectories, employing an advanced Long short-term memory (LSTM) network integrated with a state refinement module. This method predicts future trajectories by considering not just past pedestrian positions but also accounting for the behavior and locations of surrounding individuals, acknowledging the influence of human interactions. Leveraging the pedestrians’ estimated trajectories based on their historical behaviors, we have devised an e-scooter path planning system that relies on an interpolating curve planner, which can continuously analyze the driving scene, understand the behavior of other road users, evaluate the risk assessment, and predict its future trajectory. This proactive model is designed to ensure unobstructed movement in areas with substantial pedestrian traffic without collisions. Results are validated on two public datasets, ETH and UCY, providing encouraging outcomes. Our model demonstrated proficiency in anticipating pedestrian paths and augmented scooter path planning, allowing for heightened adaptability in densely populated locales. This study shows the potential of melding pedestrian trajectory prediction with scooter motion planning. With the ubiquity of electric scooters in urban environments, such advancements have become crucial to safeguard all participants in urban transit.
Anisotropic Material Behavior of 3D Printed Fiber Composites
Authors: Garcia Jordan , Lu Y Charles
Published: April 2024

Literature has shown that 3D printed composites may have highly anisotropic mechanical properties due to variation in microstructure as a result of filament deposition process. Laminate composite theory, which is already used for composite products, has been proposed as an effective method for quantifying these mechanical characteristics. Continuous fiber composites traditionally have the best mechanical properties but can difficult or costly to manufacture, especially when attempting to use additive manufacturing methods. Traditionally, continuous fiber composites used specialized equipment such as vacuum enclaves or labor heavy hand layering techniques. An attractive alternative to these costly techniques is modifying discontinuous fiber additive manufacturing methods into utilizing continuous fibers. Currently there exist commercial systems that utilize finite-deposition (FD) techniques that insert a continuous fiber braid into certain layers of the composite product. One of these machines, (known as the Mark Forge), has the fiber being introduced into the composite through the nozzle and a saw-like mechanism cuts the long fiber after it is extruded between layers. This method does not produce products with fibers homogenous through the entire product. As a result, traditional Laminate-Composite-Theory (LCT) does not apply to these composites without implementing further modifications for this inconsistency. The continuous fiber samples showed that fiber orientation had a vast effect on mechanical properties. A well oriented composite notably outperformed other fiber orientations with a drastic drop in Young’s modulus even with slight misalignment in fiber direction, but also resulted in brittle responses which may not be preferable. LCT is applied using the simulation software ANSYS workbench. It was found that the fiber orientation can cause a decrease in both the Young’s modulus and the maximum stress by over %66. The results showed considerable correlation for each orientation and can be used as an accurate predictor of mechanical characteristics for 3D printed continuous fiber composites.
A Novel Approach to Define and Validate Market Representative Routes for IUPRm Development in India
Authors: Sharma Prashant , Singh Dilbagh , Kumar Amit , Gautam Amit , Khanna Vikram
Published: April 2024

To promote real time monitoring, In use performance ratio monitoring “IUPRm” checks has been enforced in India from Apr’23 as a part of BS6-2 regulation. Since IUPRm is representative of diagnostic frequency in real driving conditions and usage pattern. therefore, a clear understanding of real-world driving is required to define IUPRm targets. This paper shares methodology and Validation steps for defining IUPRm routes for Indian market. Methodology objective is to standardize the market operating conditions over a particular region. Selected Methodology consist of three steps:

For defining IUPRm route framework, first step is to have a pre-market survey to know current In use performance ratio “IUPR” status and improvement areas in existing market vehicles. Second step is to define market representative localized on road routes based on the finding of Pre-market survey. Third step is to validate defined IUPR routes and correlate the output in reference to coverage of market operating conditions.

Routes definition (Step 2) starts with organizing customer survey to capture real driving inputs like average trip mileage, route traffic density, driving style etc. Based on survey inputs, prospective routes should be shortlisted as per route selection criteria and further based on drive pattern analysis, performed on ECU log data collected over prospective routes, route finalization can be done.

For Validation of defined IUPR routes (Step 3), Post market survey can be conducted in which market data of the models developed on IUPR methodology should be collected and general metrics like Average IUPR, Gen. denominator trend, demographical variations etc. can be analyzed. From post market survey, correlation of average IUPR and other metrics defined above, can be done to verify whether development over defined routes cover all major conditions of target market or not.

With this study, robust IUPR routes can be framed which will help the function development team in evaluating IUPRm in upcoming passenger cars.