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Special-purpose river port sediment was investigated for its potential use as a road construction material. Sediment samples were extracted from three locations in three small river ports, and detailed laboratory research was conducted to determine its basic mechanical properties and characteristics that can potentially have an adverse influence in a roadside environment. The results of the research conducted indicate that there is a need for systematic monitoring of the quality and quantity of sediment in special-purpose river ports of the Danube River Basin to maintain its mobility and prevent flooding. The basic engineering characteristics (Proctor elements, Atterberg limits, California bearing ratio, and unconfined compressive strength) determined represent the good potential of the sediment samples tested herein for use in road construction. In addition, the chemical characteristics tested indicate the need for detailed analyses of the potential environmental risk before application in civil engineering structures

There are two important conditions for the wide application of constitutive models for soil in contemporary engineering practice: a) the model should predict sufficiently well the soil behaviour at different stress paths; b) the material constants of the model can be determined from standard laboratory tests. Taking into account both conditions, a HASP model has been formulated to describe the mechanical behaviour of the overconsolidated clays, using the critical state theory and the boundary surface concept. The HASP model in a simple way overcomes many deficiencies of the Modified Cam Clay model, without introducing any additional material parameters. The formulation of the hardening rule in the function of the state parameter and overconsolidation ratio, allows the description of numerous elements of the mechanical behaviour of the overconsolidated clays. The HASP model has been implemented in software Abaqus using the Governing Parameter Method for the numerical integration of constitutive relations. The paper presents validation of the HASP model in comparison with the published results of triaxial tests as well as the possibilities of the model to adequately predict the behaviour of the overconsolidated clays through the analysis of the boundary value problem using the finite element method. The problem of the clay settlements due to phased construction of the embankment on the saturated clay surface was analyzed, assuming different overconsolidation ratios.

This paper investigates the possibility of the application of the HArdening State Parameter (HASP) constitutive model for numerical modelling of overconsolidated soft clay under embankment loading. The HASP constitutive model is a critical state soil model with a combined hardening rule that uses a state parameter to determine the dilatancy of overconsolidated clay. The model overcomes some shortcomings of the Modified Cam Clay (MCC) model in the prediction of overconsolidated clay's behavior, while preserving the simplicity and the same set of five parameters. The HASP model was implemented in finite element software. In order to verify the applicability of the model in predicting the behavior of soft overconsolidated clay due to embankment loading, two examples reported in the literature are analyzed. The numerical predictions of the HASP model are compared with the field measurements of ground settlements and pore water pressures, and with the MCC model's predictions. The results indicate that the HASP model predicts the development of the settlements of the overconsolidated soft clay deposits with a high accuracy from an engineering point of view. There are certain deviations from the field measurements in predicting the pore pressure development, which is often observed for other models as well. For the embankment settlement assessment, as important serviceability issue, the HASP model has an advantage over more complex models that require a large number of parameters. Since the parameters of the HASP model are obtained from standard laboratory tests, it can be easily applied for routine geotechnical analyses. [ABSTRACT FROM AUTHOR]

This paper deals with actual European “modal shift to rail transport” concept and related environmental issues and experience in the Republic of Serbia. The planned increase in volume of railway transport and planned railway electrification should reduce air pollution in Serbia, particularly in the urban environment. On the other hand, achieving this goal would lead to the increase in noise level in the urban environment and environmental issues in the region of thermal power plants, which are the main sources of electricity in Serbia. This paper suggests concrete measures to reduce the railway carbon footprint and noise level during the planning, design and service life of railway infrastructure.

Approximately 7 million tons of fly ash and slag are produced in thermal power plants in Serbia every year, only 3% of which is used in the cement industry. About 300 million tons of the ash-slag mixture are disposed in landfills, occupying an area of approximately 1600 hectares and generating environmental issues. Fly ash from Serbian power plants has pozzolanic properties and due to low concentration of calcium compounds (less than 10% CaO), they do not have self-cementing properties. According to the ASTM C618-15, this ash is from class F. According to the European Standard EN 197-1:2011, this ash is siliceous (type V) ash. From April 2014 to May 2015, an investigation of engineering properties of fly ash and mixtures of fly ash and slag from landfill (without or with binders of cement/lime) was conducted at the Laboratory of Soil Mechanics at the Faculty of Civil Engineering of the University of Belgrade (Serbia) and at the Institute for Testing of Materials - IMS Institute in Belgrade. The laboratory test results were showed in the study 'Utilization of fly ash and slag produced in the TPP JP EPS thermal power plants for construction of railways'. Four kinds of waste materials from Serbian power plants were laboratory tested: (a) an ash-slag mixture from landfills at the 'Nikola Tesla A' thermal power plant; (b) fly ash from silos in the 'Nikola Tesla B' thermal power plant; (c) an ash-slag mixture from landfills at the 'Kostolac A' and 'Kostolac B' thermal power plants and 'Srednje kostolačko ostrvo' landfill; (d) fly ash from the 'Kostolac' thermal power plant. The following physical and mechanical properties of ash and mixtures were investigated: grain size distribution, Atterberg limits, specific gravity, moisture-density relationship, shear strength parameters in terms of effective stresses, California Bearing Ratio (CBR), and deformation parameters. The paper presents the results of laboratory tests of the materials with and without binders, and based on the laboratory results and previous research, the paper presents possibilities of using fly ash and slag for the construction of railway substructure in the planned construction and reconstruction of railway network in Serbia. The obtained results indicate that tested fly ash and ash-slag mixture have met the technical requirements and that they have the potential to be used in railway substructure. [ABSTRACT FROM AUTHOR]

Two variants of a new pathway for the synthesis of (±)-curcumene ether are described. The key steps in these procedures are intramolecular cyclizations of 6-methyl-2-(4-methylphenyl)hept-6-en-2-ol and 2-methyl-6-(4-methylphenyl)hept-6-en-2-ol by means of an electrochemically generated phenylselenyl cation. This synthetic approach provides significantly better yields than the previously reported protocols. [ABSTRACT FROM AUTHOR]

A successful aza- Michael addition of arylamines to a conjugated enone, acryloylferrocene, has been achieved by ultrasonic irradiation of the mixture of these reactants and the catalyst, i.e., montmorillonite K-10. This solvent-free reaction, yielding ferrocene containing Mannich bases, 3-(arylamino)-1-ferrocenylpropan-1-ones, considered as valuable precursors in organic synthesis, has been performed by using a simple ultrasonic cleaner. Among 17 synthesized β-amino ketones, three were new ones, and these were fully characterized by spectroscopic means. X-Ray crystallographic analysis of three of these crystalline products enabled the insight into the conformational details of these compounds. All compounds were evaluated for their antibacterial activities against six Gram-positive and five Gram-negative strains in a microdilution assay. The observed promising antibacterial activity (with a MIC value of 25 μg/ml ( ca. 0.07 μmol/ml) as the best result for almost all tested compounds against Micrococcus flavus) seems not only to be compound but also bacterial species-specific. [ABSTRACT FROM AUTHOR]

The electrochemical chlorination of physcion (=1,8-dihydroxy-3-methoxy-6-methylanthracene-9,10-dione; 1) in AcOH and CH2Cl2 was investigated by cyclic voltammetry and prep.-scale electrolysis. This approach provided access to a number of diverse biologically and pharmacologically interesting chlorinated secondary metabolites of lichen. Unlike the only previous literature report on the 'classical' chlorination of physcion ( 1), which allowed the preparation of 4-chlorophyscion ( 2b), 4,5-dichlorophyscion ( 3b), and 2,4,5-trichlorophyscion ( 4), the present procedure also gave fragilin (=2-chlorophyscion; 2a) and 2,4-dichlorophyscion ( 3a), alongside the previously obtained 2b, 3b, and 4. All of these compounds, except for 2a, were isolated by column chromatography and medium-pressure liquid chromatography (MPLC) and characterized by spectral data. The preparative electrolysis with a 2 F⋅mol−1 charge consumption in AcOH and 10 F⋅mol−1 in CH2Cl2 may have a practical synthetic utility, since the thus obtained product mixtures can be readily fractioned by column chromatography to afford pure 2b and 4, respectively. The regioselectivity of the reaction is explained by the resonance stabilization of the corresponding arenium cations - potential products of an electrophilic attack of a 'positive' Cl species on the physcion molecule. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical bromination of 3,4,6-tri-O-acetyl-d-glucal (1) has been investigated in dimethyl sulfoxide (DMSO) by cyclic voltammetry and preparative-scale electrolyses. In this solvent, the bromination involves a bromine–DMSO complex of the type [DMSO–Br]+Br− whose reactivity towards 1 was clearly evidenced by cyclic voltammetry. Importantly, only the monobrominated glucose and mannose derivatives were obtained from electrolyses. This specific behavior was attributed to the nucleophilicity of DMSO that may react with the oxocarbenium intermediate preventing thus a possible second bromination of the transient species. The gluco/manno ratio, roughly equal to 30/70, indicated an electrophilic attack by [DMSO–Br]+Br− preferentially from the β side of the starting glycal for steric reasons. The treatment of the crude product obtained after the end of the electrolyses with acetic anhydride allowed the preparation of derivatives in which the anomeric carbon bears an acetoxy group. Based on both the cyclic voltammetry experiments and preparative-scale electrolyses, a mechanism is proposed for the bromination of peracetylated d-glucal in DMSO. These new and original results are of high interest in carbohydrate chemistry and especially for the preparation of new valuable oligosaccharides. [Copyright &y& Elsevier]

Abstract: A series of new imines and amines have been synthesized by condensation of 1H-3-ferrocenyl-1-phenylpyrazole-4-carboxaldehyde with the corresponding amines, followed by reduction with sodium borohydride. The synthesized compounds have been screened for their in vitro antimicrobial activity against 11 bacteria and three fungal/yeast strains, using disc diffusion and broth microdilution susceptibility assays. They have shown a wide range of activities, from completely inactive to the highly active compounds. [Copyright &y& Elsevier]

Abstract: Four new potential bidentate ligands – oximes of ferrocenyl ketones containing sulfur in their side chains [(E)-, and (Z)-(η5-C5H5)Fe(η5-C5H4)–C(13;(CH2) n –SCH3, n =1 or 2] were synthesised and characterized by IR, 1H and 13C NMR spectral data. Single crystal X-ray structure determinations of these compounds are also reported. [Copyright &y& Elsevier]

Marine and harbor structures, wind turbines, bridges, offshore platforms, industrial chimneys, retaining structures etc. can be subjected to significant lateral loads from various sources. Appropriate assessment of the foundations capacity of these structures is thus necessary, especially when these structures are supported by pile groups. The pile group interaction effects under lateral loading have been investigated intensively in past decades, and the most of the conducted studies have considered lateral loading that acts along one of the two orthogonal directions, parallel to the edge of pile group. However, because of the stochastic nature of its source, the horizontal loading on the pile group may have arbitrary direction. The number of studies dealing with the pile groups under arbitrary loading is very limited. The aim of this paper is to investigate the influence of the arbitrary lateral loading on the pile group response, in order to improve (extend) the current design approach for laterally loaded pile groups. Free head, flexible bored piles in sand were analyzed through the extensive numerical study. The main hypothesis of the research is that some critical pile group configurations, loading directions, and soil conditions exist, which can lead to the unsafe structural design. Critical pile positions inside the commonly used pile group configurations are identified with respect to loading directions. The influence of different soil conditions was discussed. [ABSTRACT FROM AUTHOR]

Major infrastructure projects require significant amount of natural materials, often followed by the soft soil stabilization using hydraulic binders. This paper presents the results of a laboratory study of alternative waste materials (fly ash and slag) that can be used for earthworks. Results of high plasticity clay stabilization using fly ash from Serbian power plants are presented in the first part. In the second part of the paper, engineering properties of ash and ash-slag mixtures are discussed with the emphasis on the application in road subgrade and embankment construction. Physical and mechanical properties were determined via following laboratory tests: Specific gravity, grain size distribution, the moisture–density relationship (Proctor compaction test), unconfined compressive strength (UCS), oedometer and swell tests, direct shear and the California bearing ratio (CBR). The results indicate the positive effects of the clay stabilization using fly ash, in terms of increasing strength and stiffness and reducing expansivity. Fly ashes and ash-slag mixtures have also comparable mechanical properties with sands, which in combination with multiple other benefits (lower energy consumption and CO2 emission, saving of natural materials and smaller waste landfill areas), make them suitable fill materials for embankments, especially considering the necessity for sustainable development. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of 1-ferrocenyl-3-thiabutan-1-one with methyl iodide in acetonitrile at room temperature gave dimethyl(2-oxo-2-ferrocenylethyl)sulfonium iodide, which was characterized by spectral data (1H NMR, 13C NMR, IR) and X-ray crystallographic analysis. This salt reacted with a base (sodium hydride) in acetonitrile yielding a stabilized ylide—dimethylsulfonium ferrocenoylmethylide, which was in turn, submitted to reactions with seven conjugated enones. The obtained results showed that this methodology is potentially a new and useful approach to ferrocene-containing cyclopropanes. [Copyright &y& Elsevier]

Herein, we report on the synthesis, spectral, crystallographic and electrochemical properties of a small library of N-substituted 2-ferrocenyl-1,3-thiazolidin-4-ones, designed as novel GABAA benzodiazepine-binding site ligands. The anxiolytic properties of the title compounds were evaluated in several different in vivo models, whereas the involvement of the GABAA receptor complex in the activity of the most potent compound, 2-ferrocenyl-3-(4-methoxyphenylethyl)-1,3-thiazolidin-4-one, was inferred from experiments with known GABAA-targeting agents. Ligand docking experiments revealed that the high, dose-dependent, anxiolytic activity of the new compounds might be due to their favorable interactions with the benzodiazepine-binding site of the GABAA receptor complex. The incorporation of the ferrocene core and fine tuning of the distance between the thiazolidinone core and an additional aromatic ring were judged to be crucial structural requirements for the observed anxiolytic effect. [ABSTRACT FROM AUTHOR]

Abstract: Dimethyl(2-ferrocenoylethyl)sulfonium iodide was synthesized by reacting 1-ferrocenyl-4-thiapentan-1-one with iodomethane and characterized from spectral data and single crystal X-ray structure analysis. This compound was capable of reacting with different N-, S-, and O-nucleophiles giving the corresponding β-functionalized ferrocene-containing ketones. Furthermore, dimethyl sulfide can be displaced from the dimethyl(2-ferrocenoylethyl)sulfonium ion with cyanide or carbanions derived from 1,3-bifunctional compounds and nitropropane, leading to products with a new carbon–carbon bond. [Copyright &y& Elsevier]

Abstract: An efficient catalyst for Ferrier rearrangement and hetero-Michael addition was successfully generated from a sacrificial zirconium anode into media containing reactants for these reactions. Thus, the catalyst generated, successfully promoted the allylic rearrangement of peracetylated d-glucal in the presence of a suitable S-nucleophile, giving the corresponding 2,3-unsaturated d-glucopyranose (pseudoglycal) in good to high yields. This catalyst was also shown to be capable of promoting hetero-Michael conjugate addition of S- and N-nucleophiles to the carbon–carbon double bond of methyl vinyl ketone, resulting in new carbon–sulfur and carbon–nitrogen bond formation. [Copyright &y& Elsevier]