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Found 6278 publications

Artificial aging experiments of neat and contaminated engine oil samples

Ibolya Zsoldos András Lajos Nagy J. Rohde-Brandenburger

Publication Name: Lubricants

Publication Date: 2021-06-01

Volume: 9

Issue: 6

Page Range: Unknown

Description:

This study highlights how the results from an artificial engine oil aging method compare to used engine oil samples collected from a vehicle fleet. Additionally, this paper presents the effect of contaminating the oil during aging with synthetic fuel alternatives on the physical and chemical properties of artificially aged engine oil samples. A laboratory-scale artificial thermo-oxidative aging experiment was conducted on multiple samples of commercially available formulated fully-synthetic SAE 0W-30 engine oil. The goal of the experiment was to establish the validity of the artificially aged samples as well as the validity of the underlying process in reproducibly fabricating small batches of aged engine oil with comparable chemical and physical properties to real-life used oils. Eight samples were subjected to distinct load cases (temperature, air flow rate, sample volume and aging time). Six additional samples were subjected to an intermediate load case, with five of them contaminated with selected conventional fuels and novel automotive fuel candidates. Conventional oil analysis was conducted on each sample to determine oxidation, residual additive content, kinematic viscosity and total base number. Additionally, analysis results were compared to in-use engine oil samples through PCA. The resulting oil condition after aging is in accordance with independently published results in terms of zinc dialkyldithiophosphate content and kinematic viscosity. Contaminated aging with OME3-5 resulted in a drop in antioxidant content and elevated kinematic viscosity. Based on the comparison with in-use samples, artificial aging of 200 mL engine oil at 180◦ C with 1 L/min air flow for 96 h can produce similar oil conditions as mixed vehicle use for 7000 km.

Open Access: Yes

DOI: 10.3390/lubricants9060063

Improvement the energy storage with ultracapacitor in metro railcar by modeling and simulation

I. Szenasy

Publication Name: 2008 IEEE Vehicle Power and Propulsion Conference Vppc 2008

Publication Date: 2008-12-29

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

This paper focuses on the use of modeling and simulation for the renewable energy. An energy storage system for improving performance of electric vehicles is presented. The supercapacitor contributes to the rapid energy recovery associated with regenerative braking in electric vehicles. This power system allows the acceleration and deceleration of the vehicle with minimal loss of energy. Short-distance passenger traffic on electrified lines is a domain where brake energy recuperation might reduce the total energy consumption significantly. In this paper the results of simulation model by Matlab-Simulink for an urbanmetro railcar and the method for reduce the need value of capacitance are presented. © 2008 IEEE.

Open Access: Yes

DOI: 10.1109/VPPC.2008.4677664

Nodal and edge finite element analysis of eddy current field problems

Miklós Kuczmann

Publication Name: Przeglad Elektrotechniczny

Publication Date: 2008-12-01

Volume: 84

Issue: 12

Page Range: 194-197

Description:

Eddy current field problems can be solved by different potential formulations based on the "quasi-static" Maxwell's equations. The potential formulations are obtained using a vector potential and a scalar potential, the most widely used techniques are the A, V-A, the T,φ-φformulations and their combinations. Vector potentials can be approximated by nodal or edge finite elements, scalar potentials are approximated by scalar elements. The paper presents and compares these formulations through TEAM Problem No. 7 containing a multiply connected region.

Open Access: Yes

DOI: DOI not available

Description of morphological characteristics of arabian rhinoceros beetle, Oryctes agamemnon arabicus, of date palms in Algeria

Jenő Kontschán Rais Sana Saadi Inesse

Publication Name: Iop Conference Series Earth and Environmental Science

Publication Date: 2025-01-01

Volume: 1455

Issue: 1

Page Range: Unknown

Description:

The Arabian rhinoceros beetle, Oryctes agamemnon arabicus, has emerged as a signifiicant pest of date palms in Algeria, infilicting considerable damage on these crucial agricultural ecosystems. This study provides a thorough morphological description of Oryctes collected from date palm oases in El Oued, Algeria, during the period from 2022 to 2024. Through careful identifiication of the specimens, it was confiirmed that O. a. arabicus is the only subspecies present in the region, highlighting its specifiic ecological role. The fiindings emphasize the necessity of detailed morphological analyses for accurate species identifiication, which is crucial for effective conservation strategies. By enhancing our understanding of these beetles, this research contributes valuable insights into pest management practices that are essential for mitigating the impact of Oryctes infestations. Ultimately, the outcomes of this study advocate for targeted conservation efforts of date palm and sustainable agricultural practices, ensuring the protection of date palms and the resilience of the agricultural landscape in Algeria.

Open Access: Yes

DOI: 10.1088/1755-1315/1455/1/012004

Overview of auditory representations in human-machine interfaces

None Csapó György Wersényi

Publication Name: ACM Computing Surveys

Publication Date: 2013-11-01

Volume: 46

Issue: 2

Page Range: Unknown

Description:

In recent years, a large number of research projects have focused on the use of auditory representations in a broadened scope of application scenarios. Results in such projects have shown that auditory elements can effectively complement other modalities not only in the traditional desktop computer environment but also in virtual and augmented reality, mobile platforms, and other kinds of novel computing environments. The successful use of auditory representations in this growing number of application scenarios has in turn prompted researchers to rediscover the more basic auditory representations and extend them in various directions. The goal of this article is to survey both classical auditory representations (e.g., auditory icons and earcons) and those auditory representations that have been created as extensions to earlier approaches, including speech-based sounds (e.g., spearcons and spindex representations), emotionally grounded sounds (e.g., auditory emoticons and spemoticons), and various other sound types used to provide sonifications in practical scenarios. The article concludes by outlining the latest trends in auditory interface design and providing examples of these trends.

Open Access: Yes

DOI: 10.1145/2543581.2543586

Measuring the Effectiveness of High-Intensity Virtual Training Programs in Stroke Survivors

Tamás Haidegger József Tollár Bence Csutorás Nándor Prontvai Blanka Törő Szilvia Kóra Petra Kós Barbara Kopácsi Veronika Keresztesy Júlia Kutas Dóra Kozma

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2025-01-01

Volume: 22

Issue: 10

Page Range: 103-123

Description:

The objective of this paper is to determine and compare the effects of two high-intensity virtual training programs, with different frequencies and standard care after stroke. First-time ischaemic stroke patients in subacute stage were randomized into three groups: 1 session/day high-intensity virtual training (VT1; n=20), 2 sessions/day high-intensity virtual training (VT2, n=20), standard care (CON, n=20). Each group performed a 5-week-long training program (1 hour/session, 5 days/week). Results were measured before and after the interventions. Our primary outcome was the modified Rankin Scale (mRS), which indicates the degree of independence in daily activities and the severity of disability at stroke survivors. Secondary outcomes were the Barthel Index (BI), the EuroQoL Visual Analogue Scale (EQ VAS), the Berg Balance Scale (BBS), the 6-minute walking test (6mWT), the Beck Depression Inventory (BDI), and posturograpic examination in four different positions (WEO, WEC, NEO, NEC). VT2 and VT1 groups improved significantly all of the results (all p<0,05). The result of the mRS, BI, BBS, 6mWT, BDI improved significantly (all p <0.05) in CON group, but there was no clinically meaningful changes in EQ VAS, WEO, WEC, NEO, and NEC (all p>0.05).Comparing the groups’ measured 10 results: VT2 in 9 cases (mRS, BI, EQ VAS, BBS, 6mWT, BDI, WEC, NEO, NEC), VT1 in 5 cases (mRS, 6mWT, BDI, WEC, NEC) showed greater extent improvement than CON group, furthermore the improvements of mRS and BI were significantly higher at VT2, than at VT1 (all p<0.05). Our results show that the high-intensity virtual training programs could be good opportunities for subacute ischaemic stroke patients to improve their clinical symptoms, mobility, and quality of life. Furthermore, increasing daily frequency of the training, could also increase the beneficial effects. This research is particularly important because the utilized therapies have the potential to yield significant economic benefits, by reducing long-term healthcare costs and improving overall patient outcomes.

Open Access: Yes

DOI: 10.12700/APH.22.10.2025.10.7

Taylor series method with numerical derivatives for initial value problems

G. Y. Molnarka E. M. Miletics

Publication Name: Journal of Computational Methods in Sciences and Engineering

Publication Date: 2004-01-01

Volume: 4

Issue: 1-2

Page Range: 105-114

Description:

The Taylor series method is one of the earliest analytic-numeric algorithms for approximate solution of initial value problems for ordinary differential equations. The main idea of the rehabilitation of these algorithms is based on the approximate calculation of higher derivatives using well-known technique for the partial differential equations. In some cases such algorithms will be much more complicated than a R-K methods, because it will require more function evaluation than well-known classical algorithms. However these evaluations can be accomplished fully parallel and the coefficients of truncated Taylor series can be calculated with matrix-vector operations. For large systems these operations suit for the parallel computers. The approximate solution is given as a piecewise polynomial function defined on the subintervals of the whole interval and the local error of this solution at the interior points of the subinterval is less than that one at the end point. This property offers different facility for adaptive error control. This paper describes several above-mentioned algorithms and examines its consistency and stability properties. It demonstrates some numerical test results for stiff systems herewith we attempt to prove the efficiency of these new-old algorithms.

Open Access: Yes

DOI: 10.3233/jcm-2004-41-213

Numerical study on the micro-mechanical behaviour of artificial granular materials

Majid Movahedi Rad M. Amine Benmebarek

Publication Name: Proceedings of the 2020 Session of the 13th Fib International Phd Symposium in Civil Engineering

Publication Date: 2020-01-01

Volume: Unknown

Issue: Unknown

Page Range: 86-93

Description:

Numerical models for the simulation of the micro-mechanical behaviour of granular assemblies have a wide range of applications, for instance in material science, process engineering, environmental engineering, railway engineering and geotechnical engineering (in this study we examined one macro-grain but what important is behaviour of granular assemblies). In this examination, experimental tests and numerical computations using the discrete element method (DEM) are carried out to evaluate the micro-mechanical behviour of the granular materials. For this purpose, artificial materials are taken into consideration for experimental Brazilian laboratory tests, and then according to the experimental results the DEM model is calibrated. Artificial crushable materials are produced by mixing cement and silt according to their mass ratio, in which cement can provide bonding and silt is the main filling material. In the DEM model, a 3D crushable granular material 'macro-grain' is built up from a large number of micro-grains which are associated according to crushable parallel bond properties. The behaviour of the single crushable grains and the fragmentation patterns under different contact configuration and load position are studied. The DEM simulation results show that the contact configuration type and load position affect the fragmentation patterns and loading capacity.

Open Access: Yes

DOI: DOI not available

Mathematical modeling of automotive supply chain networks

Krisztián Szabó Akos Domotorfi Tamás Péter

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2016-01-01

Volume: 44

Issue: 3

Page Range: 181-186

Description:

The aim of this research is to set up a possible model for describing automotive supply chain networks. The work to be presented analyses the real-world environment and its changes in a broader view. The research provides the extension of the mathematical modeling domain, accordingly. The paper studies the basic relational structure of automotive supply chain, where the methodology is determined by the classical business strategic levels. This is done by combining the theories of network and theories for traffic systems. We uncover the hidden relational parallelism between the automotive supply chain and positive systems, complex networks and find that the industry network shows some similar scale-free structural properties indicating the existence of a typical dependence and dominance structure with complex dynamical behavior.

Open Access: Yes

DOI: 10.3311/PPtr.9544