This paper presents the content changes in the Chemical Oxygen Demand (COD) solubilised in hydrolisates obtained from thermally disintegrated municipal waste biofractions. A series of tests related to biowaste undergoing thermal treatment at the following temperatures: 55, 75, 95, 115, 135, 155 and 175°C were conducted for 0.5, 1 and 2 hours. The highest increase in COD solid fraction solubilisation (238%) was observed for the samples disintegrated at 175°C for 2 hours. The values of the reaction rate coefficient k20 = 0.6 d-1 and temperature coefficient θ = 1.023 were determined. Statistical analysis of the multiple regression (correlation coefficient R = 0.89) showed that the temperature has a greater impact on COD solid fraction solubilisation - determined β = 0.66. The multiple correlation coefficient for the treatment time was β = 0.61.
The objective of the present study was to investigate the effects of Sn addition on the mechanical and corrosion properties of Mg-1Zn-1Zr-xSn (x = 1, 2, 3, 4, 5 wt.%) alloys prepared by powder-in-tube rolling (PTR) method. The PTR-treated Mg alloys reached 98.3% of theoretical density. The hardness of the alloy increased with Sn addition. Two main intermetallic phases, Mg2Sn and Zn2Zr3, were formed in the alloys. The Mg2Sn intermetallic particles were observed along the grain boundaries, while the Zn2Zr3 particles were distributed in the Mg matrix. The addition of 1 wt. % Sn caused the corrosion potential to shift toward a more positive value, and the resulting alloy exhibited low corrosion current density.
In environmental matrices there are mixtures of parent drug and its metabolites. The majority of research is focused on the biological activity and toxic effect of diclofenac (DCF), there is little research on the biological activity of DCF metabolites and their mixtures. The study focused on the assessment of the biological impact of DCF, its metabolites 4’-hydroxydiclofenac (4’-OHDCF) and 5-hydroxydiclofenac (5-OHDCF) and their mixtures on E. coli strains. The biological effects of tested chemicals were evaluated using the following: E. coli K-12 cells viability assay, the inhibition of bacteria culture growth, ROS (reactive oxygene species) generation and glutathione (GSH) content estimation. Moreover, we examined the influence of the mixture of DCF with caffeic acid (CA) on E. coli cells viability. Our results showed the strongest impact of the mixtures of DCF with 4’-OHDCF and 5-OHDCF on E. coli SM biosensor strains in comparison to parent chemicals. Similar results were obtained in viability test, where we noticed the highest reduction in E. coli cell viability after bacteria incubation with the mixtures of DCF with 4’-OHDCF and 5-OHDCF. Similarly, these mixtures strongly inhibited the growth of E. coli culture. We also found synergistic effect of caffeic acid in combination with DCF on E. coli cells viability. After bacteria treatment with the mixture of DCF and its metabolites we also noted the strongest amount of ROS generation and GSH depletion in E. coli culture. It suggests that oxidative stress is the most important mechanism underlying the activity of DCF and its metabolites.
Growing emission requirements are forcing the foundry industry to seek new, more environmentally friendly solutions. One of the
solutions may be the technologies of preparing moulding and core sands using organic biodegradable materials
as binders. However, not only environmental requirements grow but also those related to the technological properties
of moulding sand. Advancing automation and mechanization of the foundry industry brings new challenges related to the moulding sands.
Low elasticity may cause defects during assembly of cores or moulds by the manipulators.
The paper presents the study of flexibility in the room temperature according to new method and resistance to thermal deformation of selfhardening
moulding sands with furfuryl resin, containing biodegradable material PCL. The task of the new additive is to reduce the
moulding sands harmfulness to the environment and increase its flexibility in the room temperature. The impact of the additive and the
effect of the amount of binder on the properties of mentioned moulding sands were analysed. Studies have shown that the use of 5% of
PCL does not change the nature of the thermal deformation curve, improves the bending strength of tested moulding mixtures and
increases their flexibility at room temperature.
The article shows the influence of environment requirements on changes in different foundry moulding sands technologies such as cold
box, self-hardening moulding sands and green sands. The aim of the article is to show the possibility of using the biodegradable materials
as binders (or parts of binders’ compositions) for foundry moulding and core sands. The authors concentrated on the possibility of
preparing new binders consisting of typical synthetic resins - commonly used in foundry practice - and biodegradable materials. According
to own research it is presumed that using biodegradable materials as a part of new binders’ compositions may cause not only lower toxicity
and better ability to reclaim, but may also accelerate the biodegradation rate of used binders. What’s more, using some kinds of
biodegradable materials may improve flexibility of moulding sands with polymeric binder. The conducted research was introductory and
took into account bending strength and thermal properties of furan moulding sands with biodegradable material (PCL). The research
proved that new biodegradable additive did not decrease the tested properties.
The paper presents possibility of using biodegradable materials as parts of moulding sands’ binders based on commonly used in foundry
practice resins. The authors focus on thermal destruction of binding materials and thermal deformation of moulding sands with tested
materials. All the research is conducted for the biodegradable material and two typical resins separately. The point of the article is to show
if tested materials are compatible from thermal destruction and thermal deformation points of view. It was proved that tested materials
characterized with similar thermal destruction but thermal deformation of moulding sands with those binders was different.