bluuebunny/crossref_metadata_2025_split huggingface dataset:
Review of PEDELECS as an alternative to conventional means of urban transportation
Authors: Teodorașcu V , Burnete N V , Burnete N 
Published: March 2024

Abstract
Sustainable transportation solutions are more crucial than ever because of the pressing need to increase resource efficiency while lowering greenhouse gas emissions. The most recent advancements in the e-cycle sector have made a significant contribution to this goal and have attracted the interest of numerous businesses that offer mobility services. This paper discusses the main topics surrounding pedal electric cycles (PEDELECS) with an accent on a niche application, namely e-cargo cycles. The paper highlights not just the defining characteristics of these categories, but also other relevant aspects such as barriers to market penetration, general legislation, benefits for specific applications, as well as the significance of incentives, local infrastructure, and urban policies. Based on the available literature, it can be concluded that PEDELECS have a considerable potential to contribute to sustainability goals in urban areas due to their numerous benefits (functionality without emissions, less space occupied on roads, ability to access destinations with increased precision, ability to travel in car-restricted areas, lower costs compared to conventional vehicles, added health benefits to the users, versatility etc.). However, there are also significant challenges and barriers that must be overcome before they can see widespread adoption.
The design and development of an Integrated Propulsion System – Phase 2: the functional electric behaviour strategy
Authors: Croitorescu V , Duran B , Giurca L 
Published: March 2024

Abstract
The paper presents the integrated propulsion system implementation steps on a L6E road vehicle. The implementation followed several technical levels which are properly described within the paper. The functional behaviour in terms of electric propulsion was defined and developed. All the dedicated components were investigated, set and customized, to equip a L6E vehicle. Currently the electric machine, the battery pack, the user interface, the speedometer, the pedals, the power electronics etc. are implemented on a real existing L6E road vehicle, after they were defined and virtually tested.
Aspects of the combustion variability analysis at an automotive engine fuelled with hydrogen
Authors: Georgescu R , Pana C , Negurescu N , Cernat A , Nutu C , Sandu C 
Published: March 2024

Abstract
Over the last decades, the use of the alternative fuels was one of the main research activities for specialists in the field of internal combustion engines. The development of the modern automotive engines is constantly challenged by the more severe emission legislation. The engine emissions levels and the fuel efficiency are directly influenced by the engine operation, reproduction of the combustion phases from one cycle to other, cyclic dispersion during combustion process being important. In general, the use of alternative fuels in internal combustion engines provides an improvement of the energetic and pollution performance, or just a slight improvement of them, but the study of the combustion process must be completed with aspects regarding the cyclic variability. In particular, using this alternative fuel, a study of cyclic variation of the combustion process would be necessary in order to establish if the normal operation of the engine can be ensured. The paper presents some aspects of the analysis of the cyclic variability at a spark ignition engine fuelled with gasoline and hydrogen. During the engine operation at the regime of 2500 rev/min speed and 55% engine load, a number of 250 consecutive combustion cycles was recorded for classic fuel use and for hydrogen use. The coefficient of cyclic variation (CCV) or the coefficient of variation (COV) is determined for different combustion parameters such as maximum pressure, maximum pressure rise rate and mass fraction burned, defined by angles at which the conventional fractions of 10%, 50% and 90% of the heat of reaction is released. Thus, the values of the COV for maximum pressure (COV)pmax, maximum pressure rise rate (COV)dp/dα, angles of 10, 50 and 90% heat release as (COV)10%, (COV)50% and (COV)90% were calculated and compared with the admissible limit of 10%. The combustion variability analysis establishes the limits of the normal operation of the spark ignition engine fuelled with gasoline and hydrogen compared with the classic fuelling method.
Hydrogen fuelling a passenger car spark ignition engine for a cleaner environment
Authors: Nutu C , Pana C , Negurescu N , Cernat A , Georgescu R 
Published: March 2024

Abstract
The tightening of the restrictions on polluting emissions in the last decade and the possibility of the disappearance of the internal combustion engine in the field of transport must motivate the researchers in the field of internal combustion engines to find new solutions to fuel the spark ignition engine, aiming to reduce the negative impact of polluting emissions on the environment. Unconventional fuels represent a very good choice to fuel the spark ignition engines, based on their excellent combustion properties and hydrogen stands out among them. This paper presents experimental results of fuelling a car spark ignition engine with mixtures of gasoline and hydrogen. The experimental investigations have shown an improvement in the combustion process of the engine, a reduction in the energetic fuel consumption, an increase in the brake thermal efficiency and a decrease in the pollutant emissions level.
Surface Defects Vibration Measurements of Automotive Tapered Roller Bearings
Authors: Sabo B A , Voloacă Ş 
Published: March 2024

Abstract
The paper investigates vibration testing methodologies for automotive tapered roller bearings. The European Union regulations have indirectly led to improvements in the NVH performance of the bearings that affect both the industrial and automotive markets. The goal of this study was to examine the influence of localized small defects on the vibrations’ magnitudes within tapered roller bearings. A Rockwell indenter was used to create three different surface defects. These three levels, representing different indentation pressures, mimic defects that could occur during manufacturing or bearing installation. Indents were placed on inner raceways, the outer raceways, and the roller bodies. After the assembly of the components, different vibration testing methodologies were applied to quantify those types of defects. This paper presents a new envelope analysis approach to monitoring for defects. The paper presents the current Fast Fourier Transform (FFT) testing approach, whereby the machine sensitivity is representative of a typical quality control bearing thresholds. This paper also presents a new, more robust method and analyzed for its suitability in the detection of localized defects.
Analytical analysis of the thermal comfort of the occupants inside a truck cabin
Authors: Manea A M , Iozsa M D , Vieru E M 
Published: March 2024

Abstract
Thermal comfort inside a truck cabin is a parameter that influences the well-being of the driver and passengers. From the very first steps of designing the driver’s seat of a vehicle, the driver’s well-being is taken into account through ergonomic parameters. To analyze the ultimate comfort inside a truck cabin, a simplified sketch of the cabin will be proposed. The three-dimensional analytical calculation model is solved using the Ansys program in the Fluid Flow (CFX) module. Through modeling and numerical simulations, the temperature inside a truck cabin, the mode of movement of the air flow and the speed of the air flow are determined. Following these tests, it is checked whether the thermal comfort conditions for the driver and passengers in a truck cabin are respected and fulfilled. These term comfort conditions are evaluated based on some comfort indices available in specialized literature.
Finite element analysis and experimental study of strain for a vehicle rear suspension
Authors: Geonea I D 
Published: March 2024

Abstract
In this paper, aspects of the study of the durability of rear suspension components of a vehicle are discussed. These aspects are addressed in two ways, namely the study by CAD modelling and finite element method simulation, and secondly by experimental analysis on a durability test bench. In order to develop these research problems, an experimental stand is virtually modelled and studied by simulation using ADAMS software. Results are obtained that characterize the operation of the test bench system kinematically and dynamically. The studies are then completed by finite element analysis of the dependent rear axle and helical springs in the suspension structure. These results are corroborated with those obtained experimentally, i.e. stresses and strains recorded on the stand. The usefulness of these studies is that they allow the validation of different components of the rear suspension in terms of fatigue strength and different types of rear axles from cars can be tested, as the stand has a modular construction and the test parameters can be adjusted.
Aerodynamic means of reducing the influence of warning accessories on drag and emissions, for intervention vehicles
Authors: Ilea L , Stan C , Vieru M 
Published: March 2024

Abstract
Aerodynamic performance of passenger vehicles is one of the most efficient methods to further reduce the CO2 emissions and comply with the increasing constraints in the legislation. Previously performed studies on exterior warning accessories (systems with visual alerting signals that may be found on intervention vehicles e.g. ambulances), indicate a significant degradation of aerodynamic coefficient (Cd). Even if this category of vehicles does not have to comply with the standard emission rules, it is important to study and discover the means to reduce aerodynamic drag for this type of vehicles considering the general aim to reduce air pollution. The target would be to have a Cd level equal to that found in the base vehicles, before transformation (i.e. often, intervention vehicles are obtained by converting a vehicle available to general customers - multistage vehicle transformation).
The current paper’s purpose is to continue the investigation on methods to improve the aerodynamic performance of intervention vehicles. This will be done by compensating the shape and dimensions of the warning devices with the addition of supplementary body elements or by adapting existing parts. The Cd value of the different configurations is assessed using computational fluid dynamics (CFD) software based on Lattice Boltzmann mathematical model. 3D models of different generic body type vehicles (sedan, hatch back, SUV) were created and immersed in a virtual wind tunnel. To simulate the real-world measurement method specific boundary conditions on walls, inlets, outlets were set while the fluid environment was defined with a network from fine (2mm length, near the studied model), to coarse (20mm length, near exterior walls).
The results indicate that there is great potential in reducing the aerodynamic drag and, by extension, fuel consumption and CO2 emissions for all body types studied. Deviations could exist due to different make designs, or diversity of warning devices for example so the results obtained have a general nature. Nevertheless, the conclusion remains the same: if one’s aim is to improve air quality or prepare for new legislation (that will also apply to intervention vehicles), the aerodynamic optimization should be further scrutinized as it can prove to be a robust method to obtain the targeted results.
Comparison between gas flame welding and shielded gas welding in case of aluminium alloys
Authors: Babiş C , Dimitrescu A , Rugescu A M , Chivu O R , Enache CI 
Published: March 2024

Abstract
Although the assembly by welding of aluminum alloys is a common assembly process, it is done in quite difficult conditions, being forced to take into account a number of shortcomings, such as: high thermal conductivity which translates into losses of high heat in the welding area; formation of aluminum oxide films that melt at high temperatures, well above the melting temperature of the alloy; large expansion coefficients that result in the appearance of large deformations, the appearance of cracks in the joint at high temperatures due to loss of mechanical strength of the alloy, but also the appearance of pores, inclusions of aluminum oxide and corrosion in various aggressive environments. Despite all these shortcomings that occur in welding, aluminum alloys can be joined indestructibly by welding. The present paper aims, is to make a comparative study, based on experimental data, of two welding assembly processes, one with gas flame and another with shielded inert gas environments-WIG, for aluminum alloys of group 6000. The base material will be presented, the preparation of the basic material for welding through the two mentioned welding procedures and the steps taken to make the welded joints. The comparative study will include the parameters of welding regimes, non-destructive defectoscopy methods with which certain discontinuities can be identified and the destructive mechanical tests. The experimental results will be able to lead to pertinent conclusions on the possibilities of aluminum alloys welding assembly, using those two welding processes mentioned above, the results being easily generalized in the industrial fields.
Dynamic system for the study of bouncing vibrations of a car with active suspension model for an independent suspension
Authors: Popa D , Popa C M , Marcu S 
Published: March 2024

Abstract
At the beginning of the paper, the quantities that characterize a dynamic system are presented. Based on them, the state equations of the dynamic system are obtained, a system that models an active suspension. The types of used controllers, their block diagrams and the influence of the adjustment parameters on the process are reviewed. Next, numerical applications are made for the study of vibrations on models with 2 degrees of freedom, for an active suspension equipped with PID and LQR controllers. These controllers, as well as the simulation of the two systems, passive and active, were modelled and simulated using MATLAB/Simulink software. The numerical results obtained after the simulation are presented in the form of diagrams. In the end of the paper, it is concluded that the designed active suspension system can improve the ride quality by minimizing the displacement of the suspended mass.
Possibilities to evaluate the vehicle’s accelerations through MATLAB Simulink simulations
Authors: Duma I , Molea A , Cordoş N , Cărăuşan H , Burnete N , Barabás I , Todoruţ A , Jurchiş B M 
Published: March 2024

Abstract
This scientific present paper explores the methods for assessing the longitudinal and lateral accelerations of a vehicle through the combination of experimental validation and MATLAB Simulink simulations. Comprehending these accelerations is essential for a number of uses, such as stability, overall performance analysis, and vehicle safety. The first step of the study is building a detailed Simulink model of the car. With an emphasis on lateral and longitudinal accelerations, this model makes it easier to simulate a range of driving scenarios and explore how a vehicle handles and behaves under different circumstances. A key element of the study is the experimental validation of the Matlab Simulink model, which involves gathering real-world data from vehicle testing and contrasting it with simulated outcomes. Simulink model iterative refinement is made possible by the integration of simulation and experimentation, which ultimately improves the model’s predictive accuracy. The study’s conclusions demonstrate the integrated approach’s potential to advance vehicle dynamics analysis and make cars safer and more effective. Furthermore, it offers insights into the optimization of vehicle designs and the development of innovative control strategies to enhance overall road safety and vehicle performance.
Analysis of different dimensions of a virtual wind tunnel and different wall conditions
Authors: Vieru E M , Iozsa D M , Manea A M , Ilea L 
Published: March 2024

Abstract
Growing interest in improving the performance of vehicles is a subject that allows for continuous research. One such branch of these researchers is energy and consumption performance. These performances describe, on a global level, the need for lower fuel consumption but also a higher energy and power performance. Therefore, to create this balance, direct control of polluting emissions, especially C02 emissions, is necessary. Creating the best mix between low fuel consumption, maximum power of internal combustion engine and low pollutant emissions is influenced by many factors. One such factor, of prime importance, is represented by the aerodynamics of vehicle, in particular the aerodynamic performance, which needs to be tested to be confirmed, so numerical values are needed. Therefore, different ways of testing in the physical or virtual environment are necessary. To facilitate the optimization of a vehicle from an aerodynamic point of view, the most practical way is the virtual wind tunnel, given the possibility to test, at the same time, more configurations. But the CFD (Computational Fluid Dynamics) simulations, sometimes, have the disadvantage of very long compilation times. So, in the presented paper the construction of an optimal virtual wind tunnel for trucks will be presented, focusing on the test area (chamber) and several configurations will be presented such as: different proximity of the tunnel walls to the tested object so a different geometry of the test chamber and condition for the type of floor with different roughness than base case to simulate a more realistic road surface. Following the CFD simulations, it was observed the influence that increasing the dimensions of the test chamber has on the results obtained, so that moving the walls away from the test model generates much more realistic results. In addition, another thing that has an impact is the roughness of the floor, which, in this particular case, generate a 10% difference between the values obtained. Therefore, it will be possible to optimize the tunnel as best as possible to have results as close as possible to reality and in a reduced time.
The influences of human factors on road accidents in Romania in the period 2013 – 2022.
Authors: Dimitriu C I , Frătilă G 
Published: March 2024

Abstract
The main objective of the study is to establish a correlation between the main causes of road traffic accidents in Romania and “human factors”. The aim of the study is to show that accidents are attributed exclusively to human mistakes in a higher percentage than. The data used in the research are taken from the database of the Traffic Police-for Road traffic accidents during 2013-2022 and from the database of the Romanian Road Authority - ARR - for road safety inspections during 2018-2021. From the perspective of human factors, the research will give answers on the nature of the causes that lead to the production / favouring of road accidents in Romania and will propose solutions to address road risks to improve road infrastructure safety. As a case study, the research will focus on the human factors that contribute to road accidents on National Road 2. Compared to other national roads, on DN 2 road accidents occur with the highest number of fatalities, approximately 8.28% of all road deaths nationwide. The analysis of findings from road safety inspection reports carried out on DN2 shows that there is a correlation between road infrastructure non-conformities and causes of road traffic accidents.
Road infrastructure safety assessment using the integrated method - case study DN2.
Authors: Dimitriu C I , Frățilă G 
Published: March 2024

Abstract
This study aims to practically test, identify vulnerabilities and analyses the limits of working tools for assessing road network safety and validate the integrated method proposed by the European Commission in the context of different technical classes of national roads in Romania. The research aims to adapt, convert, and transform the calculation values of the formulas of the proactive evaluation tool to the values used by national norms for road design and construction. 2 evaluation parameters are analysed, which represent the width of the traffic lane, respectively the widths and type of shoulders. On the other hand, the study is a tool for analysing road infrastructure safety, for efficiently allocating resources and for prioritising specific road safety inspections on the most dangerous sections of roads. The case study is the comparison of the results obtained from the safety assessment of DN 2 road infrastructure, both by the proposed test method and by the method adopted by the European Commission following Member States’ comments.
Evaluation of different vehicle types by using modelling algorithms in road traffic virtual networks platforms
Authors: Gencărău N D , Matei L , Dumitru I , Stănciuc-Oţăt O V , Racilă M , Oprica A , Racila L 
Published: March 2024

Abstract
With the growing demand for simulating and analyzing road traffic, the scope of project planning, modelling, and execution will no longer be restricted to domain experts. In the future, a significantly larger portion of engineering and traffic management professionals will be required to carry out these activities. In this context, it is necessary to have several modelling and analytic algorithms that are based on the current state of affairs. Currently, the research in this subject is facing issues related to driving style variables and the integration of vehicles with the Intelligent Transportation System (ITS). Recently, there has been a focus on studying the significance of driving style for vehicle classes in connection to traffic flow, enhanced comfort, road safety, and the decrease of chemical and noise pollution. The configuration of traffic patterns is constantly changing, leading to the increasing prevalence of the idea of micro-mobility in recent years. The authors provide a comprehensive overview of the primary mathematical models employed in specific applications, as discussed before.
Particularities regarding the design and conception of a bodywork superstructure intended for the transportation of perishable goods
Authors: Beles H , Scurt F B , Tolea B A , Mitran T , Tent V I 
Published: March 2024

Abstract
The aim of this paper is to present the characteristics of the design and construction of a vehicle body superstructure intended for the transportation of perishable goods. In the first phase, the design of the superstructure was conceived, followed by its design. Then, the calculation of the mass distribution on the truck axles, as well as the calculation of the truck’s cornering, was carried out, and finally, the superstructure was made, which was mounted on the truck.
A necessary and sufficient condition for double coset lumping of Markov chains on groups with an application to the random to top shuffle
Authors: Britnell John , Wildon Mark 
Published: March 2024

Let

Q
Q

be a probability measure on a finite group

G
G

, and let

H
H

be a subgroup of

G
G

. We show that a necessary and sufficient condition for the random walk driven by

Q
Q

on

G
G

to induce a Markov chain on the double coset space

H
∖
G

/

H

H\backslash G/H

is that

Q
(
g
H
)

Q(gH)

is constant as

g
g

ranges over any double coset of

H
H

in

G
G

. We obtain this result as a corollary of a more general theorem on the double cosets

H
∖
G

/

K

H \backslash G / K

for

K
K

an arbitrary subgroup of

G
G

. As an application we study a variation on the

r
r

-top to random shuffle which we show induces an irreducible, recurrent, reversible and ergodic Markov chain on the double cosets of

S
y
m

r

×

S
y
m

n
−
r

\mathrm {Sym}_r \times \mathrm {Sym}_{n-r}

in

S
y
m

n

\mathrm {Sym}_n

. The transition matrix of the induced walk has remarkable spectral properties: we find its invariant distribution and its eigenvalues and hence determine its rate of convergence.