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Found 6374 publications

Effects of local ground conditions on site response analysis results in Hungary

No authors available

Publication Name: ICSMGE 2017 - 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue:

Page Range: 2003-2006

Description:

Ground conditions play an important role for both seismic hazard assessment and structural design for seismic actions. Generally, 1D site response analysis is the first step toward evaluating local conditions. Often the process is simplified by applying a single reference peak ground acceleration general response spectrum based on soil category. Seismic waves are amplified selectively by near-surface soil deposits that possess strain dependent stiffness and damping parameters that vary with each layer as well as with depth. In order to take these local ground conditions into account, field investigations were carried out for this study. Seismic CPT and MASW measurements were used for determining in situ small strain stiffness profiles at different locations in Hungary. Results of the investigations were used as input data for ground response analyses. Results are presented to show benefits of the detailed investigations as compared to simplified analysis methods based on estimated soil parameters and to EC-8 design spectra.

Open Access: No

DOI: DOI not available

Modeling of railway transition zones under dynamic loading

No authors available

Publication Name: ICSMGE 2017 - 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue:

Page Range: 1369-1372

Description:

Transition zones of railway tracks are intended to provide a smooth transition of the riding train, minimizing the effect of the discontinuities that exist along the track. When a train rides from an embankment onto a stiff structure, such as a bridge, tunnel or culvert, an abrupt change in the support stiffness occurs possibly inducing differential settlements. This in long term can yield to the degradation of the tracks and foundations in the transition zones. The differential settlement is especially problematic for high speed rail infrastructure as the "bump" at the transition is accentuated at high speeds. A number of techniques have been proposed or implemented to provide gradual stiffness transition at the problem zones, such as methods to ensure gradually changing pad stiffness, application of long sleepers or installation of auxiliary rails in the transition zone. The problems associated with the transition zones require a complex analysis. For efficient modeling of the mechanisms resulting in gradual line deteriorations in the transition zones the understanding of the 3D and dynamic effects associated with the problem seems to be essential. To enhance our understanding regarding the problem a 3D numerical model has been developed and presented for time domain analysis.

Open Access: No

DOI: DOI not available

Modeling of soil-stucture interaction in bridge design

No authors available

Publication Name: ICSMGE 2017 - 19th International Conference on Soil Mechanics and Geotechnical Engineering

Publication Date: 2017-01-01

Volume: 2017-September

Issue:

Page Range: 859-862

Description:

In bridge design use of integrated models for analysing of substructure (including foundation) and subsoil together with superstructure is quite rare, a separated approach using two interconnected models is more often. In this paper we present methods to use in structural modeling for modeling substructure, foundation and soil with emphasis on piles. In the simplest method prescribed displacements are applied on rigid supports to represent all the effects of pile foundation and surrounding soil. An advanced approach is the use of springs for modelling their complex response. Some designers include the piles in the superstructure model too, and require spring parameters for modeling the soil beside each pile element. We present how to determine spring characteristics for these approaches based on traditional analytical geotechnical consideration or force-displament curves measured or simulated. Another probably a better way could be to represent the entire support response in the superstructure modeling, especially in the case of abutments. The complex interactions can be analysed only by advanced geotechnical FEM modeling and the results can be used for deriving of simplified spring parameters as shown in this paper.

Open Access: No

DOI: DOI not available

Digital image analysis of sheet metal testing and forming

No authors available

Publication Name: 15th IMEKO TC10 Workshop on Technical Diagnostics 2017 - "Technical Diagnostics in Cyber-Physical Era"

Publication Date: 2017-01-01

Volume:

Issue:

Page Range: 176-180

Description:

Digital image analysing methods are widely used for evaluating local deformations in sheet metal tests and forming processes. The paper is focusing on tensile tests of uniform and non-uniform width flat specimens made of aluminum alloys, which are suitable for demonstrating Löders strain, Portevin-Le Chatelier (PLC) effect and for determination of Forming Limit Curve. Tests were carried out using GOM-ARAMIS® digital image analysis hardware and software. Observation of local deformations during tensile tests showed that initiation and evolution of local strains depend on the position of specimens related to rolling direction of sheet. Using non-uniform width specimens the local deformations are concentrated on the smallest cross-section in the final stage of tensile test. The measured major and minor strains give points of FLC.

Open Access: No

DOI: DOI not available

Investigation of Silicone Contamination in Tribometer Experiments Using FT-IR and XPS Technology †

Dominika Pintér Márkó Kovács

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

During tribometer experiments, the condition of the applied lubricants plays a crucial role in determining friction and wear properties. Oil degradation can significantly influence measurement outcomes, making it essential to understand the chemical changes that may occur during tribometric experiments. The objective of this study is to systematically investigate the source of silicone contamination and its temperature dependence. Tribometer experiments were conducted at 40, 60, 80, 100, and 120 °C, followed by FT-IR spectroscopy to analyze the lubricant after each measurement. Additionally, wear scars were examined using X-ray photoelectron spectroscopy to determine the presence of silicone within the surface layers. To assess potential alternative contamination sources, a single-drop system was employed, which excludes tubing, thereby providing a controlled environment to verify the origin of the silicone peaks. The results of this study are expected to enhance the reliability of tribometer measurements by identifying contamination sources and optimizing the experimental setup.

Open Access: Yes

DOI: 10.3390/engproc2025113069

Placebo and Nocebo Effects on Sports and Exercise Performance: A Systematic Literature Review Update

Bhavya Chhabra Attila Szabo

Publication Name: Nutrients

Publication Date: 2024-07-01

Volume: 16

Issue: 13

Page Range: Unknown

Description:

Sports performance could be affected by placebo and nocebo effects. The last literature review on placebo and nocebo effects on sports and exercise performance was published in 2019. In the past five years, several new studies have been published. This review aimed to update the previous synthesis and evaluate the results of new studies focusing on placebo or nocebo interventions in sports and exercise by determining the form and magnitude of their effect. Hence, we searched for empirical studies published from 2019 until the end of May 2024 indexed in PubMed, Medline, Web of Science, EBSCO, and Google Scholar databases. The search yielded 20 eligible studies with control or baseline-control conditions, focusing on nutritional, mechanical, and other mixed ergogenic aids. They yielded small to large placebo effects (Cohen’s d) for nutritional (d = 0.86), mechanical (d = 0.38), cream and gel (d = 0.05), and open-label placebo (d = 0.16) interventions. The pooled effect size for placebo effects was moderate to large (d = 0.67), larger than in the earlier review, suggesting that placebo effects can improve motor performance even more than previously reported. However, based on five measures from three studies, the nocebo effects were almost twice as large (d = 1.20). Accordingly, the current findings support and expand the last review in the field by yielding additional support for placebo and nocebo effects in sports and exercise.

Open Access: Yes

DOI: 10.3390/nu16131975

Improved control performance of the 3-DoF aeroelastic wing section: a TP model based 2D parametric control performance optimization

Alexandra Szollosi Péter Baranyi

Publication Name: Asian Journal of Control

Publication Date: 2017-03-01

Volume: 19

Issue: 2

Page Range: 450-466

Description:

Based on the most recent Tensor Product model transformation solutions, the paper presents an improved control performance for the most recent version of the three Degree of Freedom aeroelastic wing section model including Stribeck friction, according to signals pitch, plunge, trailing edge and control value, based on practical engineering criteria such as overshoot, undershoot, signal end values and settling time. This is achieved through proposing a novel two dimensional parametric convex hull manipulation based method for Tensor Product model transformation based Control Design Frameworks. The approach provides two TP model representations for the different requirements of the controller and observer of a given model, opening the possibility to utilize the TP model transformation's convex hull manipulation potential in control performance optimization for a separate optimization of the two TP model representations. Numerical simulation results are provided to illustrate the control performance improvements of the aeroelastic wing section model through the proposed 2D parametric convex hull manipulation based design method.

Open Access: Yes

DOI: 10.1002/asjc.1418

Assessment of the remaining life of bituminous layers in road pavements

Kálmán Adorjányi

Publication Name: TEM Journal

Publication Date: 2017-02-01

Volume: 6

Issue: 1

Page Range: 64-70

Description:

In this paper, a mechanistic-empirical approach is presented for the assessment of bearing capacity condition of asphalt pavement layers by Falling Weight Deflectometer measurements and laboratory fatigue tests. The bearing capacity condition ratio was determined using past traffic data and the remaining fatigue life which was determined from multilayer pavement response model. The traffic growth rate was taken into account with finite arithmetic and geometric progressions. Fatigue resistance of layers' bituminous materials was obtained with indirect tensile fatigue tests. Deduct curve of condition scores was derived with Weibull distribution.

Open Access: Yes

DOI: 10.18421/TEM61-09

The development of mathematical competences in hungarian teacher training education

No authors available

Publication Name: Annales Mathematicae et Informaticae

Publication Date: 2017-01-01

Volume: 47

Issue:

Page Range: 243-251

Description:

In this paper we present research results on the assessment of K1-4 (pupils from age 7 to age 10) teacher training student’s mathematical knowledge and competences as one of the most important parameters of school teaching quality. Teachers’ abilities in grades K1-4 are among the most important in-school factors influencing the quality of pupils’ learning. A large-scale longitudinal study was conducted in which the elementary mathematical knowledge and skills of a group of teacher training students from 5 different institutes was assessed by means of a paper and pencil test that was administered both at the beginning and at the end of their second year mathematical course in the 2016/2017 academic year. This course is a methodical course in some institutions, which has an essential influence on the final results of this research. The 27-item-test covered the new standards for mathematics in the K1-4 elementary school curriculum. We have observed that those students coming from institutions providing separate methodical courses can gain better knowledge in explaining simple mathematical relations and notions than those students whose institutions do not provide methodical background in specific courses.

Open Access: No

DOI: DOI not available