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Found 6278 publications

Investigation of the Tribological Effects of Nano-Sized Transition Metal Oxides on a Base Oil Containing Pour Point Depressant and Viscosity Modifier

Publication Name: Chemengineering

Publication Date: 2025-02-01

Volume: 9

Issue: 1

Page Range: Unknown

Description:

This study investigates the tribological effects of nano-sized metal oxides (ZrO2, CuO, Y2O3 and TiO2) in Group III type base oil containing 0.3% pour point depressant (PPD) and 5% viscosity modifier (VM) to enhance friction and wear performance. The homogenized lubricant samples with varying concentrations of oxide nanoparticles (0.1–0.5 wt%) on a linear oscillating tribometer performed static and dynamic frictional tests. Optical and confocal microscopy surface analysis evaluated the wear of the specimen, and SEM and EDX analyses characterized the wear tracks, nanoparticle distributions, and quantification. The cooperation between PPD and nanoparticles significantly improved friction and wear values; however, the worn surface suffered extensively from fatigue wear. The collaboration between VM and nanoparticles resulted in a nanoparticle-rich tribofilm on the contact surface, providing excellent wear resistance that protects the component while also favorably impacting friction reduction. This study found CuO reduced wear volume by 85% with PPD and 43% with VM at 0.5 wt%, while ZrO2 achieved 80% and 63% reductions, respectively. Y2O3 reduced wear volume by 82% with PPD, and TiO2 reduced friction by 20% with VM. These nanoparticles enhanced tribological performance at optimal concentrations, but high concentrations caused tribofilm instability, highlighting the need for precise optimization.

Open Access: Yes

DOI: 10.3390/chemengineering9010001

Fuzzy rule base model identification by bacterial memetic algorithms

Publication Name: Studies in Computational Intelligence

Publication Date: 2009-09-03

Volume: 222

Issue: Unknown

Page Range: 21-43

Description:

Fuzzy systems have been successfully used in the area of controllers for a long time. The Mamdani method is one of the most popular inference systems for practical applications. The main problem of Mamdani-type inference system and other fuzzy logic based controllers is how to gain the fuzzy rules the inference system based on. Several approaches have been proposed for automatic rule base identification. The bacterial type evolutionary algorithms have been successfully applied for solving this task. These algorithms are based on the Pseudo-Bacterial Genetic Algorithm and are supplied with operations and methods (e.g. the Levenberg-Marquardt method) to complete their task more efficiently. The goal is to create more accurate fuzzy rule bases from input-output data sets as quickly as possible. In this work, we summarize the bacterial type evolutionary algorithms used for fuzzy rule base identification. © 2009 Springer-Verlag Berlin Heidelberg.

Open Access: Yes

DOI: 10.1007/978-3-642-02187-9_3

Tutorial on the emergence of local substructure failures in the railway track structure and their renewal with existing and new methodologies

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-24

Volume: 14

Issue: 1

Page Range: 80-103

Description:

The construction and maintenance of a railway track is an expensive process. Therefore, nowadays, except for advanced countries, considerable attention must be paid to apply the optimal maintenance of railway lines. In Hungary, until 2020 nearly 11% of railway tracks were renewed and rehabilitated from EU support, which means millions of Euros, i.e. billions of Hungarian Forints. It also follows from the support that planned preventive maintenance works must be performed on the renewed and rehabilitated lines. On the other hand, it takes away significant costs from the non-renewed (non-rehabilitated) lines maintenance works, but naturally, less money does not mean less failures, so cost-effective technologies are needed. A segment of maintenance is the local substructure problem(s). In this article, this segment will be mentioned from the development of the failures, through the applied technologies, to the possible new solutions like injection and the using of geosynthetic cementitious composite mats (so called GCCMs).

Open Access: Yes

DOI: 10.14513/actatechjaur.00565

Ecological footprint as an indicator of corporate environmental performance—empirical evidence from hungarian smes

Publication Name: Sustainability Switzerland

Publication Date: 2021-01-02

Volume: 13

Issue: 2

Page Range: 1-20

Description:

Small‐ and medium‐sized enterprises (SMEs) play a significant role in the national economies of the EU member states. This economic activity has an inevitable environmental impact; however, environmental performance indicators are mostly measured at larger companies. Since the ecological footprint (EF) is a suitable measure of unsustainability, this paper considers it as a measure of the environmental impact of SMEs. An EF calculator for SMEs was developed that is freely available online, and it is a methodological innovation per se. Our previous research projects highlighted that the calculator must be easy‐to‐use and reliable; therefore, the calculator considers only the common, standardizable, and comparable elements of EF. Our results are based on validated ecological footprint data of 73 Hungarian SMEs surveyed by an online ecological footprint calculator. In order to validate and test the usefulness of the calculator, interviews were conducted with respondents, and results were also checked. The paper presents benchmark data of ecological footprint indicators of SMEs obtained from five groups of enterprises (construction, white‐collar jobs, production, retail and/or wholesale trade, and transportation). Statistical results are explained with qualitative data (such as environmental protection initiatives, business models, etc.) of the SMEs surveyed. Our findings could be used as a benchmark for the assessment of environmental performance of SMEs in Central‐ and Eastern Europe.

Open Access: Yes

DOI: 10.3390/su13021000

Organizational Internal Factors and Sustainable Performance: A Serial Mediation Model

Publication Name: Emerging Science Journal

Publication Date: 2025-02-01

Volume: 9

Issue: 1

Page Range: 362-381

Description:

Objective: The present study aims to explore the relationships between big data analytics capability, circular economy practices, and SMEs’ sustainable performance in Pakistan. It investigates notable factors determining SMEs’ sustainable performance, including employees’ perceived usefulness, data-driven culture, and leadership competency mediating the mentioned relationships. Method: The study employs quantitative research based on a positivist philosophy orientation. Data were collected through a structured questionnaire distributed among the employees of 350 SMEs operating in Pakistan’s different regions. Findings: The study's results demonstrated the direct effects of big data analytics capability on sustainable performance, employee perceived usefulness, and data-driven culture. Additionally, circular economy practices influence sustainable performance; employee perceived usefulness and leadership competency. Finally, the results highlighted that each relationship is subject to partial mediation, which indicates the role of employee-perceived usefulness and data-driven culture in the relationship between big data analytics and sustainable performance and employee-perceived usefulness associated with the relationship between circular economy practices and sustainable performance. Novelty: The present study highlights that all three of the previous topics are consistent and significantly contribute to the existing literature by providing a model with the main factors that determine SMEs’ sustainable performance, which can be sufficient for countries’ developing economies.

Open Access: Yes

DOI: 10.28991/ESJ-2025-09-01-020

The configurable digital neural network with emulated digital cellular neural network cores

Publication Name: 2006 IEEE International Conference on Mechatronics Icm

Publication Date: 2006-12-01

Volume: Unknown

Issue: Unknown

Page Range: 312-315

Description:

A configurable Artificial Neuron Network that is capable of establishing both the emulated digital Cellular Neural Network (CNN) and the static Multilayered Feedforward Neural Network (MFNN) is described. The configurable neural network is designed with the method of modularity where each module is a three weighted input neuron. The network can be optionally large limited only by the gate number available on a chip. © 2006 IEEE.

Open Access: Yes

DOI: 10.1109/ICMECH.2006.252545

Analysis of the Effect of Mixed Eccentricity Fault on Controlled Induction Machines via Finite Element Method

Publication Name: 2025 19th International Conference on Electrical Machines Drives and Power Systems Elma 2025 Proceedings

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The eccentricity in induction machines is a geometrical fault when the axis of rotation deviates from the ideal. As a result, the air gap between the stator and the rotor varies. Since the eccentricity is caused by a geometric misalignment, finite element method is used to model the fault in this paper and the phenomenon is detected by spectral analysis of the stator currents. In addition, the effect of eccentricity on the controlled drive is also investigated by numerical simulations.

Open Access: Yes

DOI: 10.1109/ELMA65795.2025.11083515

FACTORS EFFECTING FEMALE STARTUPPERS IN HUNGARY

Publication Name: Economics and Sociology

Publication Date: 2021-01-01

Volume: 14

Issue: 4

Page Range: 186-203

Description:

The present paper focuses on female startup founders in Hungary. Numerous studies examine female entrepreneurship, but the topic of female startups is a less explored area. The research was carried out in two stages: at first in 2019 through an online survey and in-depth interviews, and then in May 2021 with in-depth interviews due to the delays caused by the COVID-19 pandemic. Mixed research methodology was used and comprised of an online questionnaire administered in startup-themed closed social media groups (n=113) and in-depth interviews among experts and members of the ecosystem (n=7+7). The aim was to conclude how potential female startup founders could be encouraged and what form of support should be given to them, as well as to explore the effects of the Covid-19 pandemic on female startup entrepreneurs. The results show that 70 percent of respondents have their own business, these were set up by both sexes between the ages of 24 and 35. The respondents mostly use equity when starting their businesses. Although the proportion of women among startup founders is very low, a positive entrepreneurial attitude can be observed among them. The startup ecosystem is centralised in Hungary; it is only emerging in some major university cities outside the capital. The strengthening role of startup communities and social media is unquestionable. Furthermore, the results reveal limiting factors, especially complex ones hindering female start-ups, which can typically be traced back to family and social reasons. To overcome these obstacles governments should continue facilitating startup development. The pandemic was considered as an opportunity to promote new ideas and features, concentrate on design and finetune their startup businesses.

Open Access: Yes

DOI: 10.14254/2071-789X.2021/14-4/11

A new start? Revision of the genera Anauchen, Bensonella, Gyliotrachela and Hypselostoma (Gastropoda, Eupulmonata, Hypselostomatidae) of Southeast Asia with description of 46 new species

Publication Name: Zookeys

Publication Date: 2025-01-01

Volume: 1235

Issue: Unknown

Page Range: 1-338

Description:

Hypselostomatidae is a large family of terrestrial pulmonate molluscs currently represented by 284 extant species, most confined to Southeast Asia. The current system of grouping species into genera is based on the morphology of the apertural barriers and the level of last whorl detachment. However, these characters overlap, challenging generic definitions. In this paper, these characters are evaluated and a novel classification proposed for hypselostomatid species belonging to the genera Anauchen (17 species), Bensonella (36 species), Boysidia (7 species, in part) and Hypselostoma (85 species). We assigned all species belonging to the genera Bensonella and Hypselostoma into two and four species groups respectively, which are characterised by combinations of morphological traits. Altogether 46 new species are described, seven species in Anauchen: A. crassus Gojšina, Hunyadi & Páll-Gergely, sp. nov., A. evanidus Gojšina & Páll-Gergely, sp. nov., A. grandiportus Gojšina, Grego & Páll-Gergely, sp. nov., A. obesus Gojšina, Hunyadi & Páll-Gergely, sp. nov., A. picasso Gojšina & Páll-Gergely, sp. nov., A. turritus Gojšina, Hunyadi & Páll-Gergely, sp. nov., A. jokaii Gojšina & Páll-Gergely, sp. nov.; 19 species in Bensonella: B. alycaeus Gojšina & Páll-Gergely, sp. nov., B. cardiostoma Gojšina, Vermeulen & Páll-Gergely, sp. nov., B. cristatissima Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. dha Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. dracula Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. exploda Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. fracta Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. microdentata Gojšina & Páll-Gergely, sp. nov., B. mitochondria Gojšina, Vermeulen & Páll-Gergely, sp. nov., B. mirabilis Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. montawa Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. multidentata Gojšina, A. Reischütz & Páll-Gergely, sp. nov., B. nitens Gojšina & Páll-Gergely, sp. nov., B. obex Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. perfecta Gojšina & Páll-Gergely, sp. nov., B. sericata Gojšina & Páll-Gergely, sp. nov., B. serrata Gojšina, Hunyadi & Páll-Gergely, sp. nov., B. spelaea Gojšina, Grego & Páll-Gergely, sp. nov., B. spinosa Gojšina, Hunyadi & Páll-Gergely, sp. nov.; 20 species in Hypselostoma: H. aquila Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. bubalus Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. circumcarinatum Gojšina, Auffenberg & Páll-Gergely, sp. nov., H. coriaceum Gojšina & Páll-Gergely, sp. nov., H. aenigma Gojšina, Grego & Páll-Gergely, sp. nov., H. fortunatum Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. fungus Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. geckophilum Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. iunior Gojšina & Páll-Gergely, sp. nov., H. ophis Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. platybasis Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. populare Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. sculpturatum Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. similare Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. sorormajor Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. sororminor Gojšina, Hunyadi & Páll-Gergely, sp. nov., H. torta Gojšina, Auffenberg & Páll-Gergely, sp. nov., H. vesovici Gojšina & Páll-Gergely, sp. nov., H. vicinum Gojšina, Auffenberg & Páll-Gergely, sp. nov., H. vujici Gojšina & Páll-Gergely, sp. nov. One replacement name is proposed: H. tertiusfrater Gojšina & Páll-Gergely, nom. nov. pro Boysidia salpinx F. G. Thompson & Dance, 1983, non Hypselostoma salpinx (van Benthem Jutting, 1961) (originally described as Gyliotrachela). Gyliotrachela and Antroapiculus are both treated as junior synonyms of Hypselostoma. An additional 28 species and subspecies are reassigned to the synonymies of other taxa.

Open Access: Yes

DOI: 10.3897/zookeys.1235.145281