The objective of this study was to determine the effect of advanced oxidation process with the use of Fenton’s reaction on the effectiveness of anaerobic treatment of wastewaters originating from the wood industry that were characterized by a high concentration of formaldehyde. Experiments were established to analyze changes in COD content and in the concentration of formaldehyde in treated wastewaters, additional analyses were carried out to assay quantitative and qualitative changes in the biogas produced. The first stage of the experiment involved analyses of the effectiveness of the tested wastewaters treatment only in the process of methane fermentation. At the second stage of the experiment, the biological process was preceded by chemical pre-treatment of wastewaters with Fenton’s reagent. The conducted study proved that the investigated variants of chemical pre-treatment of wastewaters had a significant effect on increasing the total biogas production. In contrast, no significant effect of the applied technology was demonstrated on changes in the concentration of the analyzed contaminants in the treated wastewaters.
Chalcedonite is a diatomaceous sedimentary rock, which, on account of a very small occurrence area, is included into a group of unique rocks. It occurs at Dęborzynka, Gapinin, Lubocz and Teofilów deposits, located on the Rawska Plateau in the region of Tomaszów Mazowiecki and Nowe Miasto. The deposit in Teofilów is the only documented one and it is now being exploited. The surface of this deposit is 577 437 m2 and its geological resources were determined to be 21.587 - 106 kg (21 587.0 thousand tones). The main component of this rock is chalcedon (69.0-96.6 vol.%), however quartz, opal, iron hydroxides, pyrite, manganese compounds and clay minerals occur in small quantities. The active surface of chalcedonite is relatively small and it was determined as 3-6 m2/g. Chalcedonite had a mesoporous structure of a significantly high pore homogeneity, and the total volume of these pores was 0.03-0.04 cm3/g. On account of its small spatial distribution chalcedonite is a unique rock, which has multi-resource properties. It is useful for manufacturing perlite-like material, crystobalite, wollastonite and mullite. It was also found to be a valuable raw material for the production of pastes, scouring powders, grinder tools and also as good filler for the production of : paints, varnishes, enamel ware, lute and putty materials. Because of its mesoporous structure and due to extended outer surface of the grains, chalcedonite is utilized in water treatment technology, mostly as an effective filtration material. A high usefulness of chalcedonite bed for manganese and iron removal from water shows mostly the presence of a low height of iron removal zone in the filter, and it is also manifested by a relatively short time of introduction into effective manganese(II) removal, as well as by good hydraulic properties of the material, which enable to achieve high mass capacities of the filter and to reach long filtration cycles. Chalcedonit is a very good carrier of manganese oxides and its surface modification of leads to the creation of chemically active bed, which enables removal of manganese(II) from water with high efficiency and without the introduction process. Chalcedonite bed effective removes of ammonia nitrogen from the water in the process of nitrification and waste water treatment. Chalcedonite can be also taken into account as a sorbent for the removal of oil spills.
The effects of Mg and Ca on sulfide modification of sulphur steel were studied to elucidate the difference between micromagnesium treatment and micro-calcium treatment for the inclusion of sulphur steel. The results show that the inclusions in the steel appeared with an oxide core of Al2O3 and MnS wrapped. After the addition of Mg, the core was changed to spinel, and the MnS coating was changed to Mn-Mg-S. After Ca was added, the core was changed to Ca-Al-O, and the MnS coating was changed to Mn-Ca-S. The Mg content was higher than Ca content in the sulfides of the steel. Therefore, Mg was more effective than Ca in terms of sulfide modification with the same content of Mg and Ca in steel, but the yielding rate of Mg was lower than that of Ca. The Mg content in the oxide core was higher than Mg of the coating of the inclusions in the steel treated with Mg or Mg-Ca. In contrast, the Ca content in the oxide core was lower than Ca of the coating of the inclusions in the steel treated with Ca or Mg-Ca. MnS formed and precipitated during the melt solidification process. The complex sulfide (Mg-Mn-S) was precipitated around MgO·Al2O3 in the Mg treated steel during the cooling process. CaS inclusion was precipitated on the CaO·Al2O3 inclusions in the liquid Ca-treated steel. Thus, CaS was formed first, whereas MnS was formed during the cooling process, followed by the formation of complex sulfide (CaS+MnS), which finally precipitated around CaO·Al2O3 in the Ca-treated steel.
The experimental pharmacologist Prof. Stanisław Jerzy Czuczwar, Vice President of the Polish Academy of Sciences, tells us about how he got into medical research, about the search for new epilepsy treatments, and how pharmaceuticals are in a way akin to cell phone towers.
The work presents the results of the experimental research concerning the impact of a heat treatment (toughening) of aluminum bronze CuAl10Fe4Ni4 on its mechanical properties. The conditions of the experiments and selected results are described. A detailed description of the effects of individual heat treatment conditions namely low and high temperature aging is also presented in the work.
Prof. Mirosław Wielgoś, MD, Rector at the Medical University of Warsaw, talks about why women of all ages should undergo prenatal testing and where they can turn for help.
During the past several years big changes have been observed in waste water disposal, noticeable particularly in the improvement of water protection and sewage treatment. An important element of waste water disposal still requiring improvement is a low development of sewage systems in rural and urban areas. The main problem is an increasing amount of sludge, high degree of sediment hydration and considerable ability to anaerobic decomposition, a lack of areas for managing sediments near big cities and deposits of sediments on storage areas. Selected issues of waste water disposal and sludge handling in the Mazovian Province against a background of waste water disposal and sludge handling in Poland were presented in the article.
The influence of the hold time of the austempering heat treatment at 280°C on the microstructure and corrosion resistance in NaCl-based media of austempered ductile iron was investigated using X-ray diffraction, micro-hardness measurements, corrosion tests and surface observations. Martensite was only found in the sample which was heat treated for a short period (10 minutes). Corrosion tests revealed that this phase does not play any role in the anodic processes. Numerous small pits were observed in the α-phase which is the precursor sites in all samples (whatever the value of the hold time of the austempering heat treatment).
The effect of heat treatment on the corrosion resistance of Ti-6Al-4V alloy was investigated in the artificial saliva solution (MAS). It has been revealed that the thermal annealing treatment temperature favors the cathodic reactions and reduce the protective properties of passive film. The heat treatment causes the enrichment of β phase in vanadium. The lowest corrosion resistance in the artificial saliva revealed the Ti-6Al-4V alloy heated for 2 hours at 950°C. Heterogeneous distribution of vanadium within the β phase decreases the corrosion resistance of the Ti-6Al-4V.
The study presented in this paper concerned the possibility to apply a heat treatment process to ductile cast-iron thin-walled castings in order to remove excessive quantities of pearlite and eutectic cementite precipitates and thus meet the customer’s requirements. After determining the rates of heating a casting up to and cooling down from 900°C feasible in the used production heat treatment furnace (vh = 300°C/h and vc = 200°C/h, respectively), dilatometric tests were carried out to evaluate temperatures Tgr, TAc1start, TAc1end, TAr1start, and TAr1end. The newly acquired knowledge was the base on which conditions for a single-step ferritizing heat treatment securing disintegration of pearlite were developed as well as those of a two-step ferritization process guaranteeing complete disintegration of cementite and arriving at the required ferrite and pearlite content. A purely ferritic matrix and hardness of 119 HB was secured by the treatment scheme: 920°C for 2 hours / vc = 60°C/h / 720°C for 4 hours. A matrix containing 20–45% of pearlite and hardness of 180–182 HB was obtained by applying: 920°C for 2 hours or 4 hours / vc = 200°C/h to 650°C / ambient air.
Heat treatment processes, due to qualitative requirements for the cast machinery components and restrictions on energy consumption resulting on the one hand from environmental concerns, and on the other hand from a requirements coming from minimization of manufacturing costs, are resulting in searching after a technologies enabling obtainment of satisfactory results, in form of improved mechanical properties mainly, while minimizing (limiting) parameters of successive operations of the heat treatment. Heat treatment of the T6 type presented in this paper consists in operations of heating of investigated alloys to suitably selected temperature (range of this temperature was evaluated on the base of the ATD method), holding at such temperature for a short time, and next rapid cooling in water (20 oC) followed by artificial ageing, could be such technology in term s of above mentioned understanding of this issue. Performed T6 heat treatment with limited parameters of solutioning operation resulted in visible increase in tensile strength Rm of AlSi7Mg, AlSi7Cu3Mg and AlSi9Cu3(Fe) alloys.