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Found 6341 publications
Possibilities for further development of the driver's seat in the case of a non-conventional seating positions
Publication Name: Heliyon
Publication Date: 2024-04-15
Volume: 10
Issue: 7
Page Range: Unknown
Description:
The seat significantly contributes to driving safety. Ergonomic seats prevent physical strain and fatigue, so attention and concentration do not drop so quickly, which helps to avoid accidents. The article generally presents the development of seats used in cars and the current areas of use of rotatable seats. Furthermore, it gives an overview of the possible seating positions for fully autonomous vehicles. The article leads the reader through the crash test simulation focusing on the model used. Subsequently, the article presents the research results so far and the possibilities for further development of the driver's seat. The article highlights the change in the driver's movement kinematics as a crucial observation. This change significantly increases the risk of serious injury. In frontal collisions, the modified seat consistently demonstrates results below the specified limit. It is important to note that there are injury values that increase, but these are not a problem because they remain below the limit. In the case of a side collision, the aim was less to reduce injury values and more to better coordinate the kinematics of the passenger's movement during the accident. It can be concluded that this is achievable with the modified seat, as the passenger's movements are notably more predictable and coordinated under these circumstances.
Open Access: Yes
Water Droplet Collison and Erosion on High-Speed Spinning Wheels
Publication Name: SAE International Journal of Engines
Publication Date: 2024-04-04
Volume: 17
Issue: 5
Page Range: Unknown
Description:
The water droplet erosion (WDE) on high-speed rotating wheels appears in several engineering fields such as wind turbines, stationary steam turbines, fuel cell turbines, and turbochargers. The main reasons for this phenomenon are the high relative velocity difference between the colliding particles and the rotor, as well as the presence of inadequate material structure and surface parameters. One of the latest challenges in this area is the compressor wheels used in turbochargers, which has a speed up to 300,000 rpm and have typically been made of aluminum alloy for decades, to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage. One such fluid is the condensed water in the low-pressure exhaust gas recirculation channel (LP-EGR) formulated at cold starts and low-speed high load conditions. This kind of design has been developed to reduce nitrogen oxide emissions and is used in both gasoline and diesel engines. This article presents a state-of-the-art review of this WDE process, focusing on the formation of the condensed water before the compressor wheel, summarizing the influencing factors of WDE and the effects of the damage including using component testbench experiences and simulation methodologies. Inspection possibilities such as high-speed camera measurement and vibration analysis are also an important part of the document.
Open Access: Yes
Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development
Publication Name: International Journal of Molecular Sciences
Publication Date: 2024-04-02
Volume: 25
Issue: 8
Page Range: Unknown
Description:
In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress–strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.
Open Access: Yes
DOI: 10.3390/ijms25084336
Correction to: Deindustrialization, Tertiarization and Suburbanization in Central and Eastern Europe. Lessons Learned from Bucharest City, Romania (Land, (2023), 12, 9, (1731), 10.3390/land12091731)
Publication Name: Land
Publication Date: 2024-04-01
Volume: 13
Issue: 4
Page Range: Unknown
Description:
In the original publication [1], there was a mistake in the legend for Figure 1 and Figure 4. A map legend can be explained either by text within the figure (where space permits) or by numbering the conventional signs within the figure, and explaining them below the figure (where space is more limited). In Figure 1 and Figure 4, the second method of explanation was initially used (by means of the numbers explained under the figure), but later, according to the indications received from the referents, the numbers in the figures were replaced by their explanations (according to the version uploaded on 3 September 2023). Due to an unfortunate error, in the version uploaded on 6 September 2023, Figure 1 and Figure 4 were uploaded with the conventional numbered signs in the legend, but without the explanation of the numbers below the figure, making the figures much more difficult to explain. Therefore, we request that these two figures be replaced with their variant, where the legend is explained in the text, as indicated by the referents. The correct legend appears below. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.
Open Access: Yes
DOI: 10.3390/land13040486
Assessing the Paradox of Autonomous Vehicles: Promised Fuel Efficiency vs. Aggregate Fuel Consumption
Publication Name: Energies
Publication Date: 2024-04-01
Volume: 17
Issue: 7
Page Range: Unknown
Description:
As autonomous vehicles (AVs) continue to evolve and approach widespread adoption in the near future, the touted benefits of improved fuel efficiency at an individual level come under scrutiny when considering the overall impact on fuel consumption. This research delves into the paradoxical relationship between the promising technology of AVs, their impact on traffic capacities, travel demand, and the subsequent influence on aggregate fuel consumption. While AVs have demonstrated enhanced fuel efficiency when considered as a singular mode of transportation, our study reveals a contrasting trend when scaled to a broader societal context. Through comprehensive analysis of the literature, we discovered that, at lower limits of energy savings achievable by a single AV, the overall fuel consumption increases by a staggering 42% compared to conventional human-driven vehicles. This counterintuitive outcome is a result of the aggregate effect of increased AV usage, leading to higher traffic volumes and travel demands. Conversely, at higher thresholds of energy savings by individual AVs, the percentage of fuel consumption increment diminishes, but remains notable. Even with advanced energy-saving features, the overall fuel quantity still experiences a substantial 30% increase compared to conventional vehicles when scaled up to widespread AV use. Our findings emphasize the importance of considering the holistic impact of AVs on transportation systems and energy consumption. As society transitions towards AV-dominated traffic, policymakers and stakeholders must address the challenges associated with increased travel demand, potential traffic congestion, and the resultant implications on fuel consumption.
Open Access: Yes
DOI: 10.3390/en17071589
Investigating the Factors Influencing the Strength of Cold-Formed Steel (CFS) Sections
Publication Name: Buildings
Publication Date: 2024-04-01
Volume: 14
Issue: 4
Page Range: Unknown
Description:
The utilization of cold-formed steel (CFS) sections in construction has become widespread due to their favorable attributes, including their lightweight properties, high strength, recyclability, and ease of assembly. To ensure their continued safe and efficient utilization, this review provides a comprehensive investigation into the factors influencing the strength of CFS members. This analysis encompasses design codes, prediction methodologies, material properties, and various structural configurations. This review uncovers discrepancies among existing design codes, particularly noting conservative predictions in AISI and AS/NZS standards for composite and built-up sections. Additionally, the effectiveness of prediction methods such as the direct strength method and effective width method varies based on specific structural configurations and loading conditions. Furthermore, this review delves into recent advancements aimed at enhancing fire resistance, connection design, and the composite behavior of CFS structures. The influence of factors such as eccentricity, sheathing materials, and bolt spacing on structural performance is also examined. This study underscores the crucial role of accurate prediction methods and robust design standards in ensuring the structural integrity and safety of CFS constructions. Through a comparative analysis, it is revealed that AISI and AS/NZS standards exhibit conservatism in predicting nominal buckling loads compared to experimental data. Conversely, a non-linear finite element analysis demonstrates a strong correlation with laboratory tests, offering a more accurate prediction of nominal buckling capacity. Overall, this review offers comprehensive insights aimed at optimizing CFS structural design practices. By identifying key areas for future research and development, this work contributes to the ongoing advancement of safe and efficient CFS construction applications.
Open Access: Yes
Analysis of Digital Tourist's Purchasing Decision Process Based on Feedback and Opinions
Publication Name: Decision Making Applications in Management and Engineering
Publication Date: 2024-04-01
Volume: 7
Issue: 1
Page Range: 270-289
Description:
Today, tourism and digitalisation are very much intertwined. The phenomenon of tourism in the digital space - digital tourism - emerged with the birth of the internet and has grown in intensity over the years. The evolution of digitalisation has brought about a paradigm shift that has not only led consumers to adopt information and communication technologies, but has also greatly transformed consumer behaviour, preferences and motivations. Indeed, the development of technology has disrupted the traditional booking trends of tourists, their attitudes towards tourism and the social groups of tourists by providing dynamic online communication channels. Digital tourism users - digital tourists - are increasingly aware of the information and communication technologies, services and tools available to them, and are able to shape the market offer tailored to their needs through their actions and the data they provide. One of the most effective means of doing this is to share feedback and opinions online. In our research, I provide secondary information to support the importance of feedback and opinions, clarify its role in digital tourism, and then investigate the phenomenon of electronic-world-of-mouth through a questionnaire survey and decision tree analysis, and highlight the insights and implications of eWOM for digital tourists' behaviour in the online space based on opinions.
Open Access: Yes
Advanced elasto-plastic topology optimization of steel beams under elevated temperatures
Publication Name: Advances in Engineering Software
Publication Date: 2024-04-01
Volume: 190
Issue: Unknown
Page Range: Unknown
Description:
A topology optimization algorithm of steel beams under the influence of elevated temperature, considering the geometrically nonlinear analysis of imperfect structures, is proposed in this work. The proposed methodology is developed for addressing topology optimization problems in the presence of initial geometric imperfections and thermoelastic-plastic analysis by developing the bi-directional evolutionary structural optimization (BESO) method. Two comprehensive examples of lipped channel beams and steel I-section beams are provided to demonstrate the effectiveness of the proposed approach. The considered examples explore the impact of elevated temperature on the topology optimization of imperfect steel beams, considering the interplay between thermal effects, structural imperfections, and nonlinear behavior. The results highlight the significance of integrating temperature effects in achieving optimal and robust steel beam designs. Furthermore, the openings generated by the proposed algorithm can efficiently disrupt the continuous heat flow within the material, leading to regions with reduced thermal conductivity compared to solid regions.
Open Access: Yes
Optimising Portfolio Risk by Involving Crypto Assets in a Volatile Macroeconomic Environment
Publication Name: Risks
Publication Date: 2024-04-01
Volume: 12
Issue: 4
Page Range: Unknown
Description:
Portfolio diversification is an accepted principle of risk management. When constructing an efficient portfolio, there are a number of asset classes to choose from. Financial innovation is expanding the range of instruments. In addition to traditional commodities and securities, other instruments have been added. These include cryptocurrencies. In our study, we seek to answer the question of what proportion of cryptocurrencies should be included alongside traditional instruments to optimise portfolio risk. We use VaR risk measures to optimise the process. Diversification opportunities are evaluated under normal return distributions, thick-tailed distributions, and asymmetric distributions. To answer our research questions, we have created a quantitative model in which we analysed the VaR of different portfolios, including crypto-diversified assets, using Monte Carlo simulations. The study database includes exchange rate data for two consecutive years. When selecting the periods under examination, it was important to compare favourable and less favourable periods from a macroeconomic point of view so that the study results can be interpreted as a stress test in addition to observing the diversification effect. The first period under examination is from 1 September 2020 to 31 August 2021, and the second from 1 September 2021 to 31 August 2022. Our research results ultimately confirm that including cryptoassets can reduce the risk of an investment portfolio. The two time periods examined in the simulation produced very different results. An analysis of the second period suggests that Bitcoin’s diversification ability has become significant in the unfolding market situation due to the Russian-Ukrainian war.
Open Access: Yes
