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Review of geosynthetic-reinforced pile-supported (GRPS) embankments-parametric study and design methods

Rashad Alsirawan

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-24

Volume: 14

Issue: 1

Page Range: 36-59

Description:

Embankment construction on soft soil may result in excessive settlement, loss of bearing capacity, or sliding instability. However, geosynthetic-reinforced pile-supported (GRPS) embankments offer an effective technique to overcome the problems resulting from soft foundations soils. This paper presents a review of the most important parameters affecting the behaviour of GRPS embankments as well as design methods that estimate tensile forces in the geosynthetic layers and load efficiency. Results highlight the importance of using GRPS embankments, but also reveal the inconsistencies between design methods. Finally, general conclusions about the design and construction of GRPS systems are presented.

Open Access: Yes

DOI: 10.14513/actatechjaur.00566

Dynamics of entanglement after exceptional quantum quench

Ádám Bácsi Balázs Dóra Balázs Dóra

Publication Name: Physical Review B

Publication Date: 2021-02-24

Volume: 103

Issue: 8

Page Range: Unknown

Description:

We investigate a quantum quench from a critical to an exceptional point. The initial state, prepared in the ground state of a critical Hermitian system, is time evolved with a non-Hermitian SSH model, tuned to its exceptional point. The single particle density matrix exhibits supersonic modes and multiple light cones, characteristic of non-Hermitian time evolution. These propagate with integer multiples of the original Fermi velocity. In the long time limit, the fermionic Green's function decays spatially as 1/x2, in sharp contrast to the usual 1/x decay of noninteracting fermions. The entanglement entropy is understood as if all these supersonic modes arise from independent quasiparticles (though they do not), traveling with the corresponding supersonic light cone velocity. The entropy production rate decreases with time and develops plateaus during the time evolution, signaling the distinct velocities in the propagation of nonlocal quantum correlations. At late times, the entanglement entropy saturates to a finite value, satisfying a volume law.

Open Access: Yes

DOI: 10.1103/PhysRevB.103.085137

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

Szabolcs Fischer B. Eller

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

Literature review on steel fibre, silica fume and fly ash: improving methods for recycled and multiple recycled aggregate concretes

T. Horváth David Bozsaky M. Shmlls

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-02-14

Volume: 14

Issue: 1

Page Range: 60-79

Description:

If all concrete is to be recycled in a future scenario, recycled concrete will be needed. Usually concrete recycling causes loss of properties, but this does not have to be truth for all the mixtures. This paper shows a comprehensive knowledge about the improving methods used to keep the properties of the recycled aggregate concrete (RAC). In the reviewed literature several kinds of RAC were tested with various replacement ratios. The effect of adding steel fibres, silica fume or fly ash to the mixture were also examined both separately and together. Most of the experiments demonstrated excellent mechanical properties of the RAC compared with ordinary concretes. Based on these results the ideal RAC composition can be deduced and a future can be imagined when concrete can be recycled multiple times (MRAC).

Open Access: Yes

DOI: 10.14513/actatechjaur.00570

Article a new approach in determining the decadal common trends in the groundwater table of the watershed of lake “neusiedlersee”

Miklós Arató István Gábor Hatvani Norbert Magyar Balázs Trásy Alfred Paul Blaschke József Kovács

Publication Name: Water Switzerland

Publication Date: 2021-02-01

Volume: 13

Issue: 3

Page Range: 1-17

Description:

Shallow groundwater is one of the primary sources of fresh water, providing river baseflow and root-zone soil water between precipitation events. However, with urbanization and the increase in demand for water for irrigation, shallow groundwater bodies are being endangered. In the present study, 101 hydrographs of shallow groundwater monitoring wells from the watershed of the westernmost brackish lake in Europe were examined for the years 1997–2012 using a combination of dynamic factor and cluster analyses. The aims were (i) the determination of the main driving factors of the water table, (ii) the determination of the spatial distribution and importance of these factors, and (iii) the estimation of shallow groundwater levels using the obtained model. Results indicate that the dynamic factor models were capable of accurately estimating the hydrographs (avg. mean squared error = 0.29 for standardized water levels), meaning that the two driving factors identified (evapotranspiration and precipitation) describe most of the variances of the fluctuations in water level. Both meteorological parameters correlated with an obtained dynamic factor (r = −0.41 for evapotranspiration & r = 0.76 for precipitation). The strength of these effects displayed a spatial pattern, as did the factor loadings. On this basis, the monitoring wells could be objectively distinguished into two groups using hierarchical cluster analysis and verified by linear discriminant analysis in 98% of the cases. This grouping in turn was determined to be primarily related to the elevation and the geology of the area. It can be concluded that the application of the data analysis toolset suggested herein permits a more efficient, objective, and reproducible delineation of the primary driving factors of the shallow groundwater table in the area. Additionally, it represents an effective toolset for the forecasting of water table variations, a quality which, in the view of the likelihood of further climate change to come, is a distinctive advantage. The knowledge of these factors is crucial to a better understanding of the hydrogeological processes that characterize the water table and, thus, to developing a proper water resource management strategy for the area.

Open Access: Yes

DOI: 10.3390/w13030290

Conceptual design of a negative emissions polygeneration plant for multiperiod operations using P-graph

Kathleen B. Aviso Ákos Orosz Raymond R. Tan Jean Pimentel Ferenc Friedler

Publication Name: Processes

Publication Date: 2021-02-01

Volume: 9

Issue: 2

Page Range: 1-19

Description:

Reduction of CO2 emissions from industrial facilities is of utmost importance for sustainable development. Novel process systems with the capability to remove CO2 will be useful for carbon management in the future. It is well-known that major determinants of performance in process systems are established during the design stage. Thus, it is important to employ a systematic tool for process synthesis. This work approaches the design of polygeneration plants with negative emission technologies (NETs) by means of the graph-theoretic approach known as the P-graph framework. As a case study, a polygeneration plant is synthesized for multiperiod operations. Optimal and alternative near-optimal designs in terms of profit are identified, and the influence of network structure on CO2 emissions is assessed for five scenarios. The integration of NETs is considered during synthesis to further reduce carbon footprint. For the scenario without constraint on CO2 emissions, 200 structures with profit differences up to 1.5% compared to the optimal design were generated. The best structures and some alternative designs are evaluated and compared for each case. Alternative solutions prove to have additional practical features that can make them more desirable than the nominal optimum, thus demonstrating the benefits of the analysis of near-optimal solutions in process design.

Open Access: Yes

DOI: 10.3390/pr9020233

The status of arable plant habitats in eastern europe

Gyula Pinke

Publication Name: Changing Status of Arable Habitats in Europe A Nature Conservation Review

Publication Date: 2021-01-29

Volume: Unknown

Issue: Unknown

Page Range: 75-87

Description:

Today large parts of Eastern Europe can be considered as strikingly species-poor "agrarian-deserts". Nevertheless, the region also retains relatively large areas of species-rich farmland. Changes in the weed flora in this region, with special regard to the disappearing weed species, is the subject of relatively small numbers of international scientific studies compared to the western part of Europe. The average weed species number per plot seems to have declined less in eastern than in western countries since the Second World War. However, by the turn of the Millennium the number of threatened weed species had increased considerably, which is apparent in the recently updated national weed red lists. Many studies indicate that lower farming intensity and diversified farming systems at higher altitudes provided better conditions for the occurrence of rare species and greater diversity than intensively farmed lowlands. Unfortunately, only a few traditionally managed small fields remain in extreme habitats, and they are continuously being abandoned. Regrettably, Eastern Europe mostly lacks any conservation initiatives which directly target the preservation of rare and threatened arable weeds, consequently further declines are anticipated.

Open Access: Yes

DOI: 10.1007/978-3-030-59875-4_6

Clothoid-based Trajectory following Approach for Self-driving vehicles

Claudiu Radu Pozna Ernö Horváth

Publication Name: Sami 2021 IEEE 19th World Symposium on Applied Machine Intelligence and Informatics Proceedings

Publication Date: 2021-01-21

Volume: Unknown

Issue: Unknown

Page Range: 251-254

Description:

Lately self-driving navigation and control have obtained significant attention in many fields, such as mobile robotics or autonomous driving. Although sensing, perception, planning and following subtasks associated with autonomous vehicles persist with open challenges. In this paper the autonomous following subtask is targeted. The paper proposes trajectory following approach which is designed for self-driving vehicles.

Open Access: Yes

DOI: 10.1109/SAMI50585.2021.9378664

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

Cecília Szigeti Áron Szennay L. Radácsi J. Lisányi Endréné Beke

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