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Found 6319 publications

Review of materials used for ballast reinforcement

Majd Ahmad

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-08-25

Volume: 14

Issue: 3

Page Range: 315-338

Description:

This mini review summarizes the most recent research in ballast reinforcement. Several materials are being used for the purpose of improving the ballast layer in railways, including geosynthetics, rubber sheets and binding agents. Such methods of reinforcement have proven to be beneficial for increasing the strength, stiffness, and resilience of the ballast layer in addition to reducing settlement, breakage, degradation, and maintenance cost and frequency. Latest studies try to find the best types, placement, and combination of geosynthetics to achieve the highest strength and resistance, in addition to obtaining the optimum percentage of binding agents and methods of applying them in order to discover the most effective binder that achieves the most improvement to the mechanical properties of the layer for a reasonable price. An overview of the recent tests conducted to study the reinforced ballast layer and their results is presented in this paper, as well as an overall evaluation of the implementation of these reinforcement methods in railways.

Open Access: Yes

DOI: 10.14513/actatechjaur.00610

Synthesis and Techno-Economic Analysis of Pyrolysis-Oil-Based Biorefineries Using P-Graph

Botond Bertok Abid H. Tanzil Anamaria Paiva Pinheiro Pires Lina Martinez-Valencia István Heckl Juan C. García-Ojeda Ferenc Friedler Manuel Garcia-Perez Andres Argoti

Publication Name: Energy and Fuels

Publication Date: 2021-08-19

Volume: 35

Issue: 16

Page Range: 13159-13169

Description:

The production of renewable fuels and chemicals is a critical component of global strategies to reduce greenhouse gas emissions. In this regard, pyrolysis oil obtained from biomass comprises hundreds of chemical compounds, thus rendering it a good precursor for manufacturing a variety of fuel products of commercial interest. Despite the large number of contributions describing the products' extraction, upgrading, and potential refining schemes, no bio-oil refinery is currently in operation. The main challenge in building a bio-oil refinery lies in the lack of an economically viable process configuration. Systematic studies comparing alternative refinery concepts, or configurations, are needed to identify the most promising configuration. To the best of our knowledge, this study is the first to use process graph (P-graph) methodology for the synthesis of pyrolysis oil refineries. In particular, this work shows the effectiveness of P-graph methodology in simultaneously calculating the profitability of various biorefinery designs by using data reported in the literature and providing information on how the introduction of new technologies to the database will impact the formation of profitable biorefinery concepts. Our work demonstrates a methodology for the addition of new unit operations to the database generated from the literature. The addition of a centrifuge for water extraction and a wet oxidation system for acetic acid production resulted in the generation of 330 biorefinery configurations, seven of which have a profitability ranging from $1,650 to $23,666/h (USD) with acetic acid and levoglucosan as the main products, respectively. This demonstrates that P-graph methodology is useful for discovering optimum techno-economic scenarios that may otherwise be overlooked.

Open Access: Yes

DOI: 10.1021/acs.energyfuels.1c01299

Estimation of optimum moisture content and maximum dry unit weight of fine-grained soils using numerical methods

Elizabeth Theron Armand Augustin Fondjo R. P. Ray

Publication Name: Walailak Journal of Science and Technology

Publication Date: 2021-08-15

Volume: 18

Issue: 16

Page Range: Unknown

Description:

Soil compaction is one of the basic engineering techniques, which is carried out to guarantee the stability of soils dependent on specified strength. Nonetheless, in large-scale construction projects, the estimation of compaction features required tremendous effort and time that can be saved utilizing empirical relationships at the initial phases. It becomes critical to develop models to predict the compaction features, namely the maximum dry unit weight (γdmax) and optimum water content (WOP). This article attempts to develop models to predict the γdmax and WOP of fine-grained clay soils. Geotechnical tests such as grain size distribution, Atterberg limits, specific gravity, and proctor compaction tests are performed to assess soil samples' physical and hyro-mechanical characteristics. Multivariate analysis is conducted using MINITAB 18 software to develop the predictive models. The validation process of developed models includes the determination coefficient, probability value (p-value), comparison of the predicted values with experimental values, comparison of the models proposed in this study with other existing models found in the recent literature, and employing a different soil data set. The predicted values obtained from the models proposed in this research project are more accurate than other models developed recently. The proposed models estimate the compaction features of fine-grained clay soils with acceptable precision.

Open Access: Yes

DOI: 10.48048/wjst.2021.22792

Algebraic structure of fuzzy signatures

María Eugenia Cornejo Ĺaszĺo T. Ḱoczy Jesús Medina-Moreno

Publication Name: Fuzzy Sets and Systems

Publication Date: 2021-08-15

Volume: 418

Issue: Unknown

Page Range: 25-50

Description:

Fuzzy signatures have been used for various applications, including medical diagnosis, communication of robots based on intention guessing, and residential building evaluation. However, there exist many questions about this research topic which have not been addressed in the literature. One of the most important aims is to formally define a family of fuzzy signatures from which an algebraic structure can be obtained allowing to make computations among fuzzy signatures. This paper studies this family and defines suitable meet and join operators satisfying the properties of a lattice as an algebraic structure. A partial ordering relation, the least and greatest elements are also defined on the family of fuzzy signatures. As a consequence, fuzzy signatures can be used as truth values of fuzzy sets, which provides a great level of representativity, completely different from the interval-valued and type-2 fuzzy sets, among others.

Open Access: Yes

DOI: 10.1016/j.fss.2020.12.020

Vehicle occupant safety development with finite element method

István Lakatos Laszlo Porkolab

Publication Name: Pollack Periodica

Publication Date: 2021-08-01

Volume: 16

Issue: 2

Page Range: 30-35

Description:

Crash tests of vehicles are specified by government programs. This laws are includes only minimum requirements for individual components. Therefore additional consumer protection load cases have been developed by independent private institutes. Finite element method simulations can reduce development periods and the number of cost-intensive real crash tests. The goals of the calculations are that the early detection of component failure, the protection of occupants or pedestrians. The biggest challenge of the future, in the field of vehicle occupant safety is the interaction of the airbags and belt system with dummy by the electric vehicles, which have the concept of autonomous driving function. The aim of the research is to investigate this area using a simulation model.

Open Access: Yes

DOI: 10.1556/606.2021.00306

Natural Resources for Human Health: A New Interdisciplinary Journal Dedicated to Natural Sciences

Gautam Sethi Zhaojun Wei Barbara Sawicka Bharat B. Aggarwal In Ho Kim Chunpeng Wan Karel Šmejkal Haipeng Lv Jialin Xu Rasul Suleria Zhiling Yu Visweswara Rao Ren Wang Mohammad Amjad Kamal Tarun Belwal Onur Bender Ihosvany Camps Jaruporn Rakmai Si Mi Andrei Mocan Shafi Ullah Khan Dongdong Wang Jianbo Xiao Carlos L.Cespedes Acuña Ana Sanches Silva Hafiz Ansar Ricardo DG De Albuquerque Diego Jelena Popovićdjordjević Vince Ördög Alessandra Cincinelli Michał Tomczyk Adriano Mollica Jesus Simal-Gandara Satyajit D. Sarker Gökhan Zengin Ashwell R. Ndhlala Manoj G. Kulkarni Claudio Ferrante

Publication Name: Natural Resources for Human Health

Publication Date: 2021-08-01

Volume: 1

Issue: 1

Page Range: 1-2

Description:

No description provided

Open Access: Yes

DOI: 10.53365/nrfhh/141005

Relationship between total cell counts and exopolysaccharide production of Streptococcus thermophilus T9 in reconstituted skim milk

E. Korcz Z. Kerényi László Varga

Publication Name: Lwt

Publication Date: 2021-08-01

Volume: 148

Issue: Unknown

Page Range: Unknown

Description:

The main objective of this study was to establish a correlation between total bacterial count (TBC) and exopolysaccharide (EPS) production in a specific Streptococcus thermophilus strain. TBC was determined based on real-time quantitative polymerase chain reaction (qPCR) standard curves of S. thermophilus T9 cultured in reconstituted skim milk. EPS yields were measured following isolation and purification steps using a dextran standard curve. The relationship between TBC of and EPS production by S. thermophilus T9 was analyzed alongside these standard curves. The results showed that EPS yield reached 36.6 ± 0.8 mg L−1 following 6 h of incubation. Over the same period, the streptococcal counts measured by qPCR increased from 4.71 ± 0.15 to 7.52 ± 0.09 log10 TBC mL−1. Overall, EPS biosynthesis has been shown to be a growth-related trait in S. thermophilus T9 (R2 = 0.991). In conclusion, the monitoring of TBC may provide an insight into the mechanism of EPS production and, therefore, its use can be recommended for this purpose and for EPS quantification. To our knowledge, this is the first research that has associated qPCR-based TBC with EPS yield in S. thermophilus.

Open Access: Yes

DOI: 10.1016/j.lwt.2021.111775

Damping determination by the half power bandwidth method for a rectangular flat plate with bitumen damping layer application

Dániel Feszty Balázs Vehovszky Marcell Treszkai

Publication Name: Journal of Vibroengineering

Publication Date: 2021-08-01

Volume: 23

Issue: 5

Page Range: 1267-1277

Description:

Damping Loss Factor (DLF) is an important input parameter in Statistical Energy Analysis (SEA) simulations, therefore its accurate determination via measurement is crucial from simulation accuracy point of view. This paper presents a methodology for the accurate measurement of DLF via the Half Power Bandwidth Method (HPBM) for three test cases: A) a rectangular steel plate, b) the same plate with viscoelastic bitumen sheets imposed on the middle of plate and c) the same plate with the viscoelastic bitumen sheets placed randomly. The aim of the different bitumen layer applications was to develop a methodology for representing them in Statistical Energy Analysis, since this simulation technique takes into account only the coverage of the damping layers but not their distribution over a panel. Measurement of the DLF in random locations on the plate gave the appropriate parameters for the simulation. Measurement results were then applied in SEA simulations, which showed good agreement with the experimental results in all test cases, with the maximum difference of only 2 dB.

Open Access: Yes

DOI: 10.21595/jve.2021.21938

Bananas, coffee and palm oil: The trade of agricultural commodities in the framework of the EU-Colombia free trade agreement

Laszlo Vasa Béla Soltész Julieth P.T. Cubillos

Publication Name: Plos One

Publication Date: 2021-08-01

Volume: 16

Issue: 8 August

Page Range: Unknown

Description:

Generally, research and studies about commodities focus on price trends, analysis in terms of international competitiveness, market position structure, rate of net exports, market share, and concentration index. This paper has developed an analysis of the most influential agricultural commodities traded from Colombia to European Union, which are bananas, coffee, and palm oil. Analyzing the economic and commercial effects in two traditional agricultural commodities from Colombia (bananas and coffee) with the rise of palm oil as a commodity in the trade relation with its partner; the European Union. The structure draws from the overview of general aspects and the behavior of Colombian foreign trade, as diversification of export products and trade partners, to focus on the characteristics of the trade relationship between the European Union and Colombia. The aim is analyze the proportional relation between bananas, coffee, and palm oil exported to the EU, according to three indicators, the volume of production, exports share, and trade value, from 2008 until 2019, identifying the trends before and after the implementation of the free trade agreement. Finally, with the coefficient correlation, determine the agricultural commodity that has the strongest and positive relationship with the total agricultural exports value from Colombia to the European Union.

Open Access: Yes

DOI: 10.1371/journal.pone.0256242