Search results for " metal"
showing 10 items of 2159 documents
The use of mosses in biomonitoring of selected areas In Poland and Spitsbergen in the years From 1975 to 2014
2015
Przeanalizowano historyczne zmiany stężeń metali ciężkich: Mn, Ni, Cu, Zn, Cd i Pb zakumulowanych w próbkach mchów pobieranych do badań w Polsce, na terenach leśnych Beskidów i Karkonoszy oraz w lasach północno-wschodniej części kraju, w odniesieniu do mało zanieczyszczonych obszarów Archipelagu Svalbard, którego największą wyspą jest Spitsbergen. Wyniki badań przedstawianych w literaturze uzupełniono wynikami badań własnych, prowadzonych w 2014 r. Wykazano, że spośród wymienionych obszary Beskidów oraz Karkonoszy były i są najbardziej narażone na depozycję metali ciężkich. Stwierdzono również, że na przestrzeni lat 1975-2014 nastąpiło znaczące zmniejszenie stężeń Cu, Zn, Cd i Pb w mchach p…
Active Biomonitoring of Heavy Metal Concentrations in Aquatic Environment Using Mosses and Algae
2022
In this paper, we present an analysis of the pollution of surface water and air by the heavy metals: Mn, Fe, Ni, Cu, Zn, Cd and Pb in the area of the smelter in Ozimek (Opolskie Voivodeship, Poland). The marine algae Palmaria palmata was exposed in the Mała Panew River, and three species of forest mosses: Pleurozium schreberi, Sphagnum fallax and Dicranum polysetum were also applied. Active biomonitoring was also carried out using P. schreberi mosses to assess air pollution, since the area and the river are influenced by the smelter’s activities. Analytes were determined by atomic absorption spectrometry. Student’s T-test and Mann–Whitney U test were used to assess th…
Tuning the Basicity of Synergic Bimetallic Reagents: Switching the Regioselectivity of the Direct Dimetalation of Toluene from 2,5‐ to 3,5‐Positions
2008
Meta-meta metalation: Remarkably, toluene can be directly dimanganated or dimagnesiated at the 3,5-positions using bimetallic bases with active Me3SiCH2 ligands (see scheme, blue). In contrast, n-butyl ligands lead to 2,5-metalation (red). tmp=2,2,6,6-tetramethylpiperidide.
Direct C-H metalation with chromium(ii) and iron(ii): transition- metal host/benzenediide guest magnetic inverse-crown complexes
2009
Check M(etal)ate: The chessboard and the figures represent a special reaction in which different low-polarity metals can metalate arenes directly when they are brought into the right position. In a combination of queen (sodium) and knight (chromium or iron), it is possible for the knight (usually the weaker piece) to make a direct deadly hit on the king (benzene) in this game of elemental chess. Fil: Alborés, Pablo. Johannes Gutenberg Universitat Mainz; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Carrella, Luca M.. Johannes Gutenberg Universitat Mainz; Alemania Fil: Clegg, William. University of Newcastle; Reino Unido Fil: García Álvarez, Pablo. Univ…
STUDIES ON ALKALY METAL HALIDES AGGREGATES IN GAS PHASE
2012
A novel linear friction welding based approach for sheet-bulk joining
2019
In the last decades, the development of new, flexible manufacturing processes caused the increase of the demands for highly customized complex functional parts in many industrial fields. The peculiar design of these components often overcome conventional sheet metal and bulk metal forming processes capabilities. In order to face this issue, new hybrid techniques, capable of exploit key advantages of different processes, have to be developed. In this paper, a novel approach based on the Linear Friction Welding process is proposed to obtain sheet-bulk joints. The feasibility of the technique on high specific strength alloys is investigated through an experimental campaign.In the last decades,…
Detoxification of Copper and Chromium via Dark Hydrogen Fermentation of Potato Waste by Clostridium butyricum Strain 92
2022
The accumulation of various types of waste containing both organic and inorganic metal-containing compounds is extremely hazardous for living organisms. The possibility of polymer degradation, biohydrogen synthesis, and metal detoxification via the dark fermentation of model potato waste was investigated. For this purpose, the strict anaerobic strain was isolated and identified as Clostridium butyricum. The high efficiency of dark hydrogen fermentation of potatoes with yield of hydrogen in 85.8 ± 15.3 L kg−1 VSpotato was observed. The copperand chromium salts solutions were added to the culture fluid to obtain the concentrations of 50, 100, and 200 mg L−1 Cu(II) and Cr(VI) in the active pha…
The complementary structural studies of the double metal cyanide type catalysts for the ring opening polymerization of the oxiranes
2016
Przeprowadzono badania strukturalne katalizatorów dimetalocyjankowych (DMC) z dwoma rodzajami ligandów organicznych. Zaproponowano wyjaśnienie etapów przebiegu krzywych otrzymanych metodą analizy termograwimetrycznej i różnicowej kalorymetrii skaningowej (TG/DSC) badanych katalizatorów. Wykazano obecność kilku stopni związania ligandów w kompleksach DMC. Na podstawie wyników badań z wykorzystaniem absorpcji rentgenowskiej (XAS) stwierdzono, że centrum aktywne katalizatora stanowi atom cynku. W bezpośrednim sąsiedztwie atomów Zn wykryto obecność atomów Cl, natomiast w najbliższych sferach koordynacyjnych atomu Zn nie wykryto atomów tlenu.
Rapid changes in heat-shock cognate 70 levels, heat-shock cognate phosphorylation state, heat-shock transcription factor, and metal transcription fac…
2010
The aim of the present study was to analyze and compare the effects of several metals on the embryos of the sea urchin Paracentrotus lividus, a key species within the Mediterranean Sea ecosystem. Embryos were continuously exposed from fertilization to the following metals: 0.6 mg/l copper, 3 mg/l lead, and 6 mg/l nickel. The embryos were then monitored for metal responses at the gastrula stage, which occurred 24 h after exposure. A biochemical multi-experimental approach was taken and involved the investigation of the levels of HSC70 expression and the involvement of heat shock factor (HSF) and/or metal transcription factor (MTF) in the response. Immunoblotting assays and electrophoretic mo…
A novel scientific approach to the conservation of archaeological copper alloys artefacts
2007
A novel research approach focused on innovative materials and methods to assure the long-term stability of bronze archaeological artefacts during exhibition and storage is reported. The work deals with the application of advanced analytical techniques and the development, characterisation and testing of materials and procedures for the conservation, protection and restoration of ancient Cu-based alloy artefacts. Our first aim was the selection of Cu-based alloy artefacts from different archaeological sites in Southern Italy with respect of chemical composition, metallurgical features and corrosion products. This step allowed the identification of the ancient alloys, the study of natural pat…