Investigation of possibilities for high heavy metal content sludges utilization by incorporating them in concrete products

The safe removal of sludge, obtained during the surface treatment of different metal products, is a serious environmental problem. These sludges are usually characterized by a high content of heavy metals (Pb, Cu, Ni, Zn, Cr, Cd, Mn), low quality and are obtained in many small industrial units in the whole country, which makes their centralized treatment difficult. In world practice, different methods are used for component fixation of such sludge, in the aim to prevent leaching of the metals causing pollution of the soil and underground water. The aim of the recent work is to prepare the sludge in a form of light (keramzit) fillers by preliminary treatment with binding substances and to introduce them in non supporting concrete products - curbs, stakes and similar products. The investigation was made with two types of sludge - from a production line for thermal treatment and hardening of different parts used in machine building and from a production line for surface decoration treatment (nickel-plating and chromium-plating) of consumer products. The sludge were dried and ground and then granulated with a solution of water glass. After their solidifying the air dried granules with a size of 5 to 15 mm were treated with cement milk and air dried again. With the obtained granules, standard percolation test for leaching metals like Pb, Cu, Zn, Ni and Cr was carried out. After a preliminary calculation of concrete mixtures, these granules were mixed with Portland cement and concrete sample products were made. These molded concrete samples were characterized by their density, water absorption, and mechanical strength for defined standard periods of time. The samples were subjected to a modified percolation test for leaching metals. The metal concentration in eluates was determined by Atomic Spectral Analysis

Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines

We are presenting the electronic photo fragment spectra of the protonated pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well structured vibrational progression, while protonated monomer shows broad vibrational bands. This shows that proton bonding can block some non radiative processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the LUMAT federation (FR LUMAT 2764

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Distribution, Population Status, Ecology, and Conservation of Eastern Imperial Eagle in Thrace Ecoregion (Bulgaria and Turkey)

The Thrace geographical region comprises territories of three states and covers an area of about 70,000 km2 . At the end of the 19th century, the Eastern Imperial Eagle (Aquila heliaca) was widespread throughout the region, occupying a variety of habitats. The mid-20th century marked the beginning of its dramatic decline, and in the latter half of the century the birds breeding in Northern Thrace amounted to 15–20 pairs, Eastern Thrace harbored scattered pairs along the lower reaches of the Maritsa River, while in Western Thrace the population was estimated at 6–10 pairs only. Since 2005, the intensive conservation activities implemented in Bulgaria have improved the status of the Eastern Imperial Eagle in Northern Thrace

Grassland Alterations Do Not Affect Breeding Success, But Lead to Dietary Shifts of Eastern Imperial Eagle, a Top Predator: a Case of Successful Adaptation

Habitat transformation is identified as a global threat to biodiversity, affecting threatened raptors. In our study area, habitat change dramatically affected permanent grasslands, shrinking their availability. As we expected, the decrease in share of grasslands in eagles’ territories significantly affected occupancy rate, but not productivity: we found that occupancy rate decreased significantly, while productivity showed no trend. Understanding the adaptive capacity of top predators and how they respond to shifts in prey abundance and availability is crucial for their conservation. We investigated the diet pattern of the endangered Eastern Imperial Eagle (Aquila heliaca) facing long-term and large-scale changes

Distribution, population status, habitats, and conservation of Lesser Spotted Eagle in Bulgaria

The Lesser Spotted Eagle (Aquila [Clanga] pomarina) is a territorial raptor, distributed from Baltic region to Anatolia and Caucasus. Bulgaria is a part of the southern limit of the species distribution range. Since 2014, intensive field research in Eastern and Central Bulgaria identified an abundant and stable population of the species. For the period 2014–2023, 167 different active nests were found, and more than 450 occupied territories were mapped in Eastern and Central Bulgaria. Thus, the current population estimate is at least 1,000 breeding pairs. About 60% of the breeding population of the Lesser Spotted Eagle was situated in SPAs, but only 2.3% was located within Nature reserves, indicating insufficient protection of the species