The article presents the results of research which describes antagonism between Pb-Zn in selected plant species from the area of Czestochowa – Mirow district (north-western part of the Czestochowa Upland). There were analyzed changes in the ratio of Pb/Zn in different organs of the tested plants as a function of the Zn content changes. The content of metals in the plants and the soil was determined using atomic absorption spectrophotometry AAS. In all organs of the plants there was observed antagonistic decrease of Pb uptake and accumulation, resulting from the increase in the concentration Zn.
Antagonism between Zn and Pb in roots of the tested plants occurred at Zn content of 200–600 μg/g. In turn, antagonism in stems and flowers occurred at lower contents of zinc (100–180 μg/g). In leaves, antagonism between Pb and Zn occurred when Zn was present at the level of 300–800 μg/g.
Ex definition of the analyses confirm the presence of antagonism of lead with regard to high levels of Zn. The study also confirmed that the degree of antagonism depends on the plant species.
Cd and Pb concentrations were measured in water, sediment and plant organs collected from selective sites located along the Bogdanka river (Poznań, Poland) in the 2012 growing season. The aim of the investigations was to monitor changes in heavy metal (HM) concentrations in different media over the periods, as well as to evaluate potential of two littoral plants, Phragmites australis and Typha angustifolia, for phytoremediation under natural conditions. Investigations revealed differences in HM concentrations in water and sediments. Higher values were observed in sediments than in water. The decrease in concentrations of both HMs in sediments was noted in two of the three selected water reservoirs during growing seasons, which suggests the possibility of their adsorption and accumulation by aquatic plants. Both investigated plant species accumulated ample amount of Cd and Pb in underground and aboveground plant tissues, however T. angustifolia revealed higher Cd translocation potential than P. australis. The latter revealed higher Pb accumulation in two lakes. Moreover, the translocation ratio was usually higher in spring, especially for Pb, in both plant species. Increasing level of pollution load index in sediment along the Bogdanka watercourse indicates accumulation of measured HMs.
The purpose of the investigation was to assess the suitability of sewage sludge, brown coal and a
mix of sewage sludge and brown coal to be used for fertilizing a light soil with an increased content of lead (I0
)
and slightly contaminated with cadmium (II0
). The subject of tests were soil and plant samples taken from a pot
experiment conducted during the years 2007-2009. The tests determined the effect of the type of fertilization
on the pH and sorption properties of the soil, the contents of heavy metals in the soil and in the plants, and the
volume of crops. The fertilization types applied had an effect of slightly increasing the soil pH. The application
of sewage sludge, brown coal and the mix of sewage sludge with brown coal to the soil resulted in an improvement of the sorption properties of the soil. In the soil treated with sewage sludge and the mix of sewage sludge
with brown coal, an increase in the contents of Cd, Zn and Pb was found. This increase was, however, small and
did not change the degree of soil contamination with heavy metals. In the above-ground parts of plants fertilized
with brown coal the concentration of heavy metals was lower than in biomass from plants cultivated on the
control combination. The application of sewage sludge and the mix of sewage sludge with brown coal generally resulted also in a reduction of metal contents in the above-ground parts of the plants. This was the effect of
enriching the soil with an organic substance that improves the sorption properties. From among the fertilization
combinations tested, the application of either sewage sludge or the mix of sewage sludge with brown coal had
the most favourable effect on the crop volume. It resulted in a twofold increase in the yield compared to the
control combination.
The study includes the results of research conducted on selected lead-free binary solder alloys designed for operation at high temperatures.
The results of qualitative and quantitative metallographic examinations of SnZn alloys with various Zn content are presented. The
quantitative microstructure analysis was carried out using a combinatorial method based on phase quanta theory, per which any
microstructure can be treated as an array of elements disposed in the matrix material. Fatigue tests were also performed using the
capabilities of a modified version of the LCF method hereinafter referred to in short as MLCF, which is particularly useful in the
estimation of mechanical parameters when there are difficulties in obtaining many samples normally required for the LCF test. The fatigue
life of alloys was analyzed in the context of their microstructure. It has been shown that the mechanical properties are improved with the
Zn content increasing in the alloy. However, the best properties were obtained in the alloy with a chemical composition close to the
eutectic system, when the Zn-rich precipitates showed the most preferred morphological characteristics. At higher content of Zn, a strong
structural notch was formed in the alloy because of the formation in the microstructure of a large amount of the needle-like Zn-rich
precipitates deteriorating the mechanical characteristics. Thus, the results obtained during previous own studies, which in the field of
mechanical testing were based on static tensile test only, have been confirmed. It is interesting to note that during fatigue testing, both
significant strengthening and weakening of the examined material can be expected. The results of fatigue tests performed on SnZn alloys
have proved that in this case the material was softened.
The results of studies presented in this article are an example of the research activity of the authors related to lead-free alloys. The studies covered binary SnZn90 and SnZn95 lead-free alloys, including their microstructure and complex mechanical characteristics. The microstructure was examined by both light microscopy (LM) and scanning electron microscopy (SEM). The identification of alloy chemical composition in micro-areas was performed by SEM/EDS method. As regards light microscopy, the assessment was of both qualitative and quantitative character. The determination of the geometrical parameters of microstructure was based on an original combinatorial method using phase quantum theory. Comprehensive characterization of mechanical behavior with a focus on fatigue life of alloys was performed by means of the original modified low cycle fatigue method (MLCF) adapted to the actually available test machine. The article discusses the fatigue life of binary SnZn90 and SnZn95 alloys in terms of their microstructure. Additionally, the benefits resulting from the use of the combinatorial method in microstructure examinations and MLCF test in the quick estimation of several mechanical parameters have been underlined.
Lead-free alloys containing various amounts of zinc (4.5%, 9%, 13%) and constant copper addition (1%) were discussed. The results of
microstructure examinations carried out by light microscopy (qualitative and quantitative) and by SEM were presented. In the light
microscopy, a combinatorial method was used for the quantitative evaluation of microstructure. In general, this method is based on the
phase quanta theory according to which every microstructure can be treated as an arrangement of phases/structural components in the
matrix material. Based on this method, selected geometrical parameters of the alloy microstructure were determined. SEM examinations
were based on chemical analyses carried out in microregions by EDS technique. The aim of the analyses was to identify the intermetallic
phases/compounds occurring in the examined alloys. In fatigue testing, a modified low cycle fatigue test method (MLCF) was used. Its
undeniable advantage is the fact that each time, using one sample only, several mechanical parameters can be estimated. As a result of
structure examinations, the effect of alloying elements on the formation of intermetallic phases and compounds identified in the examined
lead-free alloys was determined. In turn, the results of mechanical tests showed the effect of intermetallic phases identified in the
examined alloys on their fatigue life. Some concepts and advantages of the use of the combinatorial and MLCF methods in materials
research were also presented.
The article presents the study results of Sn-Zn lead-free solders with the various Zn content. The results concern the hypoeutectic, eutectic and hypereutectic alloys containing respectively 4.5% Zn, 9% Zn and 13.5% Zn. Moreover, these alloys contain the constant Ag (1%) addition. The aim of the study was to determine the microstructural conditionings of their fatigue life. In particular it was focused on answer the question what meaning can be assigned to the Ag addition in the chemical composition of binary Sn-Zn alloys. The research includes a qualitative and quantitative assessments of the alloy microstructures, that have been carried out in the field of light microscopy (LM). In order to determine some geometrical parameters of the microstructure of alloys the combinatorial method based on the phase quanta theory was applied. Moreover, for the identification necessities the chemical analyses in the micro-areas by SEM/EDS technics were also performed. Based on the SEM/EDS results the phases and intermetallic compounds existing in the examined lead-free solders were identified. The mechanical characteristics were determined by means of the modified low cycle test (MLCF). Based on this method and on the results obtained every time from only one sample the dozen of essential mechanical parameters were evaluated. The research results were the basis of analyzes concerning the effects of microstructural geometrical parameters of lead-free alloys studied on their fatigue life at ambient temperature.
This work reports on cadmium and lead contaminations in the edible snail Helix pomatia harvested in Poland. One hundred and 24 samples of Helix pomatia meat collected from seven provinces (voivodeships) of Poland were analyzed for their trace metal levels by graphite furnace atomic absorption spectrometry (GFAAS). The research was conducted in 2 stages. The 1st stage analyzed snail meat prior to any further technological treatment (raw meat). In the 2nd stage, the trace element levels were measured in meat subjected to technological treatment (processed meat). The trace element contents in raw meat samples ranged from 0.06 mg kg-1 to 0.22 mg kg-1 for Cd and from 0.06 mg kg-1 to 0.18 mg kg-1 for Pb. The analyses revealed an increase in the cad- mium content from 0.12 mg kg-1 to 0.18 mg kg-1 in thermally treated snail meat and no changes in lead concentration during the two-stage heat treatment. Regulation (EC) 1881/2006 does not specify the Cd and Pb residue limits in meat of terrestrial edible snails. The limits are set for in- vertebrate aquatic organisms meat (i.e. shellfish, mollusc, cephalopod) and range from 0.5 mg/kg to 1.5 mg/kg of tissue fresh weight for Pb and from 0.5 mg kg -1 to 1 mg kg-1 for Cd (EU Commis- sion 2006). The results demonstrate that the land snail Helix pomatia has a tendency to bioaccu- mulate trace elements, and the cooking process is likely to affect (increase) the Cd content in the snail meat.
In this article, we review the research state of the bullwhip effect in supply chains with
stochastic lead times. We analyze problems arising in a supply chain when lead times are
not deterministic. Using real data from a supply chain, we confirm that lead times are
stochastic and can be modeled by a sequence of independent identically distributed random
variables. This underlines the need to further study supply chains with stochastic lead times
and model the behavior of such chains.
Increasing numbers of implanted cardiovascular electronic devices, results in a need for lead extractions, which has increased to an annual volume of over 10,000 worldwide. We present a cadaveric dissection body with a single chamber pacemaker implanted 5y before death.
In this paper results of microstructural observations for series of CuZn39Pb2 alloys produced from qualified scraps are presented. The individual alloy melts were differentiated in terms of thermal parameters of continuous casting as well as refining methods and modifications. Structural observations performed by SEM and TEM revealed formation of different types of intermetallic phases including “hard particles”. EDS results show that “hard particles” are enrich in silicon, phosphorus, iron, chromium and nickel elements. Additionally, formation of Al-Fe-Si and Al-Cr in alloy melts was observed as well. It was found that quantity and morphology of intermetallic phases strongly depends upon the chemical composition of raw materials, process parameters, modifiers and refining procedure applied during casting. It was observed that refining process results in very effective refinement of intermetallic phases, whereas modifiers, particularly carbon-based, results in formation of large particles in the microstructure.
As part of the presented work, tests were carried out to check the possibility of replacing of conventional reducers used in the lead pyrometallurgical processes by cheaper, but equally effective substitutes. For research of lead oxide reduction, the following fine-grained carbonaceous materials were used, ie anthracite dust and coal flotation concentrate, as well as traditional used coke breeze for comparison. The obtained test results indicate a similar ability to reduce the lead oxide of all studied carbonaceous materials.
The article presents the results of plasma vitrification of solid remnants from thermal waste treatment with and without the addition of a carbonate fraction obtained from lead-zinc ore flotation. The substrates used in the research were slags and ashes from medical waste treatment, incineration of municipal waste, sewage sludge as well as hazardous and industrial wastes.
The plasma treatment resulted in acquiring products of different quality depending on the processed substrate. Most of the obtained products were of vitreous and homogenic build. Treatment of remnants from incineration of hazardous and industrial wastes resulted in obtaining heterogeneous and rough surfaced products. A 20% share of the carbonate fraction enabled the obtaining of a vitrified product with a glassy surface and fracture. Hardness of the obtained products was rated in Mohs scale and ranged from 6 to 6,5. Leaching tests showed a decrease in heavy metal concentration in the leachates from vitrificates with the addition of carbonate fraction compared to the ones with it.
The phytoextraction is a process that uses living plants for cleaning up the heavy metals from contaminated soil. The cadmium and lead contamination of soils results from the application of sludge or urban composts, fertilizers, pesticides, motorization, metallurgy, and different technological processes. In industrial terrain the content of cadmium and lead in soils has increased in the recent years. This study was undertaken to evaluate the potential of Amaranthus caudatus L. ‘Atropurpureus’ and Ricinus communis L. ‘Sanguineus Apache’ for phytoextraction of cadmium and lead. Two species of ornament plants, i.e. Amaranthus caudatus L. ‘Atropurpureus’ and Ricinus communis L. ‘Sanguineus Apache’, were planted in drainless containers in a substrate artificially polluted with cadmium and lead in order to evaluate their suitability for phytoremediation of soils or substrates contaminated with these metals. Cadmium was applied at increasing rates of 0, 1, 5 and 10 mg Cd∙dm-3 in the form of cadmium sulfate 3CdSO4∙8H2O, while lead was used at 0, 100, 500 and 1000 mg Pb∙dm-3 in the form of lead acetate (CH3COO)2Pb∙3H2O. The applied doses of cadmium and lead in the experiment reflected different degrees of soil pollution. After five months of growth it was found that Amaranthus caudatus L. accumulated the biggest concentrations of cadmium and lead in leaves and the lowest concentrations in inflorescences. Ricinus communis L. accumulated the highest concentrations of cadmium in stems, while the lowest concentrations in inflorescences, whereas the biggest concentration of lead was accumulated in inflorescences and the least lead was accumulated in leaves. The biggest reduction of cadmium and lead concentrations after the completion of the experiment was found in substrates, in which Amaranthus caudatus L. was grown. The tested species of ornamental plants may be used in the phytoextraction of cadmium and lead from soils contaminated.