An Analysis of Local and Combined (Global) Scours on Piers-on-Bank Bridges

This paper examines the scour problems related to piers-on-bank bridges resulting from frequently flooded and/or constricted waterways. While local scour problems for bridge piers in riverine channels have been addressed extensively in the literature, there have been few studies addressing piers-on-bank scour scenarios. A comprehensive three-dimensional finite element analysis using the element removal (ER) technique has been performed on a recently constructed bridge with an observable scour problem on multiple piers. The analysis is further extended to study the effect of “combined scour” or extensive erosion of soil between adjacent piles. Three different loading cases were considered in the study, and the results demonstrated that the effects of local and combined scours on bridge drilled shaft foundations can be significant under the combined actions of axial, lateral loads and bending moments. Specifically, the most critical case of combined scour is when maximum moment effect is applied to the piers. The results of this study show that the interaction of soil displacement fields between adjacent piles should be investigated for bridge crossings with piers-on-bank, with a high risk of flooding during the moderate-to-low probability of the occurrence of precipitation events, as they can increase the pile head displacements and the bending moments in the soil and result in the early failure of bridges.

Trace Metal Accumulation and Phytoremediation Potential of Four Crop Plants Cultivated on Pure Sewage Sludge

Phytoremediation is a viable strategy to remove trace metal contaminants from sewage sludge but still is poorly investigated. The aim of this study was to quantify the trace metal removal of B. napus, B. juncea, H. annuus, Z. mays grown on pure sewage sludge. Each species was grown on six different sewage sludge for 8 weeks and sludge were analysed for trace metal content and physico-chemical characteristics. Our results confirmed that all the tested sludge supported plant growth. The tested sludge showed a plant vigorousness lower (46% of sludge) or similar/increased (54% of sludge) compared to control treatment. B. juncea and B. napus were the most efficient species in the bioaccumulation, of trace metals. The average percentage of metals removed by the selected species was 0.2% for As, 0.85% for Cd, 0.09% for Cr, 0.36% for Cu, 0.36% for Ni, 4.2% for Se, 1.2% for Zn. In conclusion, our results showed that phytoremediation can be applied to sewage sludge, despite the chosen species have low efficiency in trace element removal. Further studies using hyperaccumulator species are needed which may lead to a higher efficiency of the process opening up new possibilities for the management strategies of this waste.

Hogyan befolyásolja a villamosenergia-hálózatról rendelkezésre álló információ a fizikai támadások által okozott sérülékenységről alkotott képet?

Összefoglaló. A villamosenergia-rendszerek fizikai támadásokkal szembeni ellenálló képessége a közelmúltban világszerte történt események ismeretében egyre nagyobb hangsúlyt kap a tématerület kutatásaiban. Az ilyen eseményekre való megfelelő felkészüléshez elengedhetetlen az üzemeltetett infrastruktúrának, elsősorban annak gyengeségeinek pontos ismerete. A cikkben Magyarország villamosenergia-hálózatának adatai alapján készített súlyozatlan és súlyozott gráfokon végzünk vizsgálatokat, hogy megértsük a különböző stratégia mentén kiválasztott célpontok elleni támadások milyen mértékben csökkentik a topológiai hatékonyságot. A cikk célja egyben a magyar hálózat sérülékenységének általános bemutatása is, mely hasznos bemeneti információ lehet a kockázati tervek elkészítésekor. Summary. Tolerance of the power grid against physical intrusions has gained importance in the light of various attacks that have taken place around the world. To adequately prepare for such events, grid operators have to possess a deep understanding of their infrastructure, more specifically, of its weaknesses. A graph representation of the Hungarian power grid was created in a way that the vertices are generators, transformers, and substations and the edges are high-voltage transmission lines. All transmission and sub-transmission elements were considered, including the 132 kV network as well. The network is subjected to various types of single and double element attacks, objects of which are selected according to different aspects. The vulnerability of the network is measured as a relative drop in efficiency when a vertex or an edge is removed from the network. Efficiency is a measure of the network’s performance, assuming that the efficiency for transmitting electricity between vertices i and j is proportional to the reciprocal of their distance. In this paper, simultaneous removals were considered, arranged into two scenarios (single or double element removal) and a total of 5 cases were carried out (single vertex removal, single edge removal, double vertex removal, double edge removal, single vertex and single edge removal). During the examinations, all possible removal combinations were simulated, thus the 5 cases represent 385, 504, 73920, 128271 and 193797 runs, respectively. After all runs were performed, damage values were determined for random and targeted attacks, and attacks causing maximal damage were also identified. In all cases, damage was calculated for unweighted and weighted networks as well, to enable the comparison of those two models. The aims of this paper are threefold: to perform a general assessment on the vulnerability of the Hungarian power grid against random and targeted attacks; to compare the damage caused by different attack strategies; and to highlight the differences between using unweighted and weighted graphs representations. Random removal of a single vertex or a single edge caused 0.3–0.4% drop in efficiency, respectively, which indicates a high tolerance against such attacks. Damage for random double attacks was still only in the range of 0.6–0.8%, which is acceptable. It was shown that if targets are selected by the attacker based on the betweenness rank of the element, damage would be below the maximal possible values. Comparison of the damage measured in the unweighted and the weighted network representations has shown that damage to the weighted network tends to be bigger for vertex attacks, but the contrary is observed for edge attacks. Numerical differences between the two representations do not show any trend that could be generalised, but in the case of the most vulnerable elements significant differences were found in damage measures, which underlines the importance of using weighted models.

Bursts of recent transposable element activity and signatures of element removal in the monarch genome, Danaus plexippus

BackgroundLepidoptera (butterflies and moths) are an important model system in ecology and evolution. A high-quality chromosomal genome assembly of the monarch butterfly (Danaus plexippus), famous for its North American migration, is available but lacks an in-depth transposable element (TE) annotation. This provides an opportunity to explore host-TE interactions, and the impact TEs have in shaping the monarch genome.Results6.47% of the monarch genome is comprised of TEs, a reduction of 6.59% compared to the original TE annotation performed on the draft genome assembly. TE content is low compared to two closely related species, Danaus chrysippus (26.70%) and Danaus melanippus (11.87%). The biggest contributors to genome size in the monarch are LINEs and Penelope-like elements, and 37.7% of TE content is contributed by five newly identified TE families (two LINE, two Penelope-like, and one SINE). Some young DNA TE families show similar activity profiles to these LINEs, with their success putatively due to horizontal transposon transfer from species sharing the same environment. There are several recent peaks of TE activity in the monarch, with little evidence for peaks of activity more anciently. LINE fragments demonstrate signatures of genomic deletions as reported by studies on Heliconius butterflies, indicating a high rate of TE turnover. Given previous associations in other species, we investigated the association of TEs with wing colouration and immune genes. We find a single unclassified element 7kb upstream of the myosin gene locus, associated with wing colouration, and 49 immune genes with TEs within 5kb upstream of the transcription start site, presenting the potential for the involvement of TEs in regulatory functions.ConclusionsWe provide an in-depth TE annotation and analysis of TE diversity and evolution for the monarch genome. We identify highly successful novel DNA TE families, mirroring the activity profile of the most successful LINEs. We also find evidence of ongoing TE expansion and removal in the monarch, highlighting the dynamic nature of repeat content in genomes over time. Further in-depth comparative studies across closely related species will be beneficial to our understanding of the evolutionary dynamics of TEs and the processes leading to their contrasting distributions.

SOLID PHASE EXTRACTANTS BASED ON POROUS POLYMERS IMPREGNATED WITH MULTIDENTATE CHELATING LIGANDS FOR ACTINIDE AND LANTHANIDE REMOVAL

Introduction. Treatment and disposal of radioactive wastes as well as monitoring of radioactive isotope content in environmental objects are actual tasks in the developed world. Lanthanide and transuranium element removal from spent nuclear fuel of nuclear power plants allows decreasing waste amount to be dumped and diminishing the risk of environmental pollution by radionuclides. Problem Statement. Considering extreme radiotoxicity of transuranium elements and tight standards restricting their activity in air and water, there is an urgent need to develop accurate and highly sensitive methods for pollution control. Purpose. Development of solid phase extractants (SPEs) based on porous polymers impregnated with multidentate chelating ligands for lanthanide, uranium and transuranium element removal from aqueous solutions. Materials and Methods. The materials used are porous divinylbenzene polymers of POROLAS brand and styrene-divinylbenzene copolymers from Smoly SE (Kamianske); multidentate chelating ligands of actinides and lanthanides such as N,N,N´,N´-tetra-n-octyl-oxapentane-1,5-diamide (TODGA) and carbamoyl phosphine oxides (CMPO); sorbent from TrisKem (France) based on TRU Resin (Eichrom Industries, Inc.). The research techniques are inductively coupled plasma atomic emission spectrometry, IR spectroscopy, scanning electron spectroscopy, spectrofluorimetry. Results. The solid-phase extractants (SPEs) for actinide and lanthanide removal from aqueous solutions have been synthesized by impregnation of porous polymeric POROLAS matrices and TODGA, CMPO-(PhOct) and CMPO-(Ph2). Sorption kinetics has been studied and capacity values for the different sorbents have been estimated. Extractive columns for uranium and europium concentration have been manufactured. Conclusions. SPEs studied demonstrate a high efficiency in removing uranium and europium from aqueous solutions. Due to their characteristics obtained materials may be used for preconcentration of target ions in radioecologycal monitoring procedures.

Silica extraction from bauxite reaction residue and synthesis water glass

Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

Technology of Reconditioning with Hardening of Working Elements of Construction and Road Machines by Composite Coatings

The article gives the description of the developed technology of increasing wear resistance of working elements of national and foreign constructional and road machines by composite coatings, obtained on working elements cutting surfaces applying Carbo Vibro Arc Hardening method (CVAH). The technology includes the following basic operations: cleaning and fault detection of the working element, removal of the worn cutting element, compensating element production, its sharpening and welding, preparation of metal and ceramic paste for Carbo Vibro Arc Hardening method (CVAH) and its application, Carbo Vibro Arc Hardening method (CVAH) of the harden cutting surface of the working element. When hardening new working elements technological process operations connected with production and welding the compensating element is not performed. According to the carried out results the rational composition and component concentration of the paste that provides significant increase of working elements wear resistance.