High Contents Of Cu Research Articles

Cu(II)-Dependent Spine Development Injury in Zebrafish (Danio rerio) with Organ Heterogeneous Cu Imbalance.

Growing evidence suggests that the imbalance of Cu leads to multiorgan diseases or other adverse effects, but the underlying mechanisms remain largely unknown. Herein, we used zebrafish to uncover the mystery of organ heterogeneous responses to Cu stress and Cu(II)-dependent spine developmental injury in the early organogenesis stage. We first demonstrated that Cu(I) was distributed in the entire body, but high contents of Cu(II) were accumulated in the yolk sac and eye in normal zebrafish larvae. Cu exposure from birth to 144 hpf caused no obvious damage to Cu-metabolizing organs (liver and intestine), despite the elevated Cu(I) and Cu(II) levels. However, the spine was more sensitive to the Cu exposure. In the spine region, the Cu(I) level remained stable, whereas the level of Cu(II) significantly increased, which was highly associated with spine development injury. A significant negative correlation between Cu(II) and the spine-related parameters was identified. Moreover, cuproptosis caused spine development deformation during the early embryogenesis stage. Spine-related pathways such as somitegenesis significantly changed in the early embryogenesis period, and 5 spine-related pathways were significantly altered in the larval stage at 96 hpf. Our study suggested that Cu stress induced organ heterogeneous Cu imbalance and Cu(II)-dependent spine development injury in zebrafish.

Unveiling the effects of support crystal phase on Cu/Al2O3 catalysts for furfural selective hydrogenation to furfuryl alcohol

Support crystal phase plays a crucial role in the controlled CO hydrogenation over the supported catalysts. Herein, the effects of Al2O3 crystal phase (α, θ, η, and γ) on the supported Cu-based catalyst is highlighted for furfural (FAL) hydrogenation to furfuryl alcohol (FA). The evaluation results show that Cu/η-Al2O3 exhibits the best performance (FAL conversion: 99.7 %, FA selectivity: 94.0 %), highest TOF value (29.3 h−1) and lowest apparent activation energy (66.3 kJ/mol). The comprehensive characterizations unravel that Cu/η-Al2O3 has the smallest Cu nanoparticles and the highest content of Cu+ and Cu0, which facilitates H2 dissociation and FAL adsorption. The reaction mechanisms suggest that Cu/η-Al2O3 has the strongest FAL adsorption and FA desorption capacity. Moreover, it is demonstrated that FAL is linear chemical adsorption on the catalyst surface in the η1(O) configuration, which avoids the furan ring hydrogenation, and thereby, results in the high FA selectivity. This work would provide some references for developing the high-efficiency CO hydrogenation catalysts.

Optimizing structure and magnetic softness of low-Nb-content Fe-Si-B-Nb-Cu nanocrystalline alloys by regulating Si/B ratio and Cu content

The influences of Si/B ratio and Cu content on the melt-spun and crystallized structures and magnetic properties of low-Nb-content Fe-Si-B-Nb-Cu alloys have been studied. The results show that increasing the Si/B ratio in Fe78SixB19.5-xNb1.5Cu1 (Cu1Six) alloys deteriorates amorphous-forming ability, and gradually transforms the melt-spun structure from an amorphous phase (x = 9.5–10.5) to amorphous phase plus α-Fe texture (x = 11.5–13.5). An appropriate rise in Cu content eliminates the α-Fe texture in melt-spun structure and Fe77.5SixB19.5-xNb1.5Cu1.5 (Cu1.5Six) alloys all appear amorphous within x = 9.5–13.5. After annealing, the average α-Fe grain size (Dα-Fe) and coercivity (Hc) of the Cu1Six nanocrystalline alloys initially decrease and then increase with rising the Si/B ratio, reaching their minimums at x = 11.5. For the Cu1.5Six nanocrystalline alloys, both the Dα-Fe and Hc consistently decrease with increasing the Si/B ratio, and remain significantly lower than those of the Cu1Six alloys. The increased Si/B ratio also steadily reduces the saturation magnetic flux density (Bs) of both alloy series. The Cu1.5Six nanocrystalline alloys with x = 12.5–13.5 exhibit the optimized nanostructure and soft magnetic properties featuring the Dα-Fe, Hc, Bs, and effective permeability at 100 kHz of 24.8–25.2 nm, 10.5–11.0 A/m, 1.50–1.52 T, and 7300–7500, respectively. The increase in the Si/B ratio facilitates α-Fe nucleation whereas hinders grain growth, and a higher content of Cu promotes high-number-density α-Fe nucleation and strengthens the competitive growth among the α-Fe grains, further inhibiting their overgrowth. The synergistic effect leads to a refined nanostructure and improved magnetic softness.

Corrosion Behavior of Q420qNH Plate and Welded Joint in Deicing Salt Medium by Cyclic Immersion + Infrared Drying

The corrosion behavior of Q420qNH steel plate and welded joint in deicing salt medium is investigated by cyclic immersion + infrared drying accelerated corrosion experiments. The results show that the corrosion products are mainly Fe2O3 and FeOCl under the influence of Cl− concentration differential corrosion microcells in the immersion corrosion anoxic stage, and the corrosion products are mainly β-FeOOH, γ-FeOOH, and Fe3O4 under the influence of oxygen concentration differential corrosion microcells catalyzed in the infrared drying stage. Throughout the corrosion process, the corrosion weight gain and average corrosion rate of the welded sample are always lower than that of the plate sample. The Iα-FeOOH/Iβ-FeOOH + FeOCl peak intensity ratio of the welded sample is always higher than that of the plate sample and the heat-affected zone (HAZ) sample. The corrosion types of the three samples are inhomogeneous total corrosion + pitting, and the depth of the pits in the plate is much larger than that in the weld and the HAZ. In the late stage of corrosion, the self-corrosion current density is: plate > HAZ > weld, and the resistance of the rust layer of the weld and HAZ samples is 1.66 times and 1.31 times that of the plate sample, respectively. This is because the microstructure of the weld and HAZ are composed of a large number of fine acicular ferrite and lath-shaped bainite generated inside the original austenite grains, and the small angle grain boundary is not conducive to the initiation and expansion of pitting corrosion. In addition, the higher content of Cu, Cr, Ni, and other elements in the weld can refine the rust layer products and effectively impede the intrusion of Cl−, contributing to corrosion resistance improvement. As the combined effect of Cl− and immersion anoxic environment inhibits the formation of α-FeOOH and promotes the formation of a large number of loose and unstable β-FeOOH and soluble FeOCl, the weathering steel is not well protected by the rust layer during cyclic immersion corrosion in deicing salt medium.

Preparation of Heterogeneous Fenton Catalysts Cu-Doped MnO2 for Enhanced Degradation of Dyes in Wastewater.

Herein, a series of heterogeneous Fenton catalysts, Cu doped MnO2 (CDM), with different Cu/Mn molar ratios were prepared via a hydrothermal reaction. Meanwhile, detailed characterizations were used to study the structures of CDM, and it is amazing that the morphology of CDM changed from nanowires to nanoflowers with an increasing amount of Cu doped. Apart from this, both the specific surface area and oxygen vacancy increased obviously with the increasing Cu/Mn molar ratio. Then, the degradation of different dyes was utilized to evaluate the catalytic activity of different CDM with H2O2 used as the oxidizing agent, and the 50%-CDM with the highest content of Cu doped displayed the best catalytic activity. Herein, the degradation efficiency (D%) of Congo red (CR) solution with low concentration (60 mg/L) reached 100% in 3 min, while the D% of CR solution with a high concentration (300 mg/L) reached 99.4% after 5 min with a higher dosage of H2O2. Additionally, the 50%-CDM also displayed excellent reusability, for which the D% values were still higher than 90% after the 14th cycles. Based on the structure characteristics and mechanism analysis, the excellent catalytic capacity of 50%-CDM was due to the combined influence of large specific surface area and abundant oxygen vacancy. Thus, a promising heterogeneous Fenton catalyst was developed in this study, which proved the treatment efficiency of actual dye wastewater.

Drought Differently Modifies Tolerance and Metal Uptake in Zn- or Cu-Treated Male and Female Salix × fragilis L.

The aim of this study was to determine the tolerance to metals (Zn, Cu) and drought of male and female Salix × fragilis L. under isolated and combined treatments, and to assess the metal uptake and profiling of metabolic plant responses. The 14-day experiment was performed in a hydroponic system, and metals were applied at 1.5 mM in a Knop’s solution. Drought simulation was achieved by adding sorbitol at a moderate level (200 mM). Isolated Zn treatment enhanced plant growth, more pronouncedly in females. Equimolar Cu treatment caused diverse reactions, and females exhibited significantly higher tolerance. Male specimens were less tolerant to isolated drought and to combined drought and metal presence. The highest contents of Cu and Zn were found in roots, compared to the aboveground tissues (wooden rods and leaves), of both female and male metal-treated plants. Simultaneously applied drought limited Zn accumulation in roots and elevated its translocation to leaves while increasing Cu accumulation, predominantly in females showing higher tolerance. Both isolated and combined drought and metals reduced leaf water content, caused the allocation of mineral nutrients (Ca, Mg, K, and Na), and affected metabolism in a stressor-specific and sex-dependent manner. For males, Cu accumulation in the leaves was significantly correlated with the majority of metabolites, while for both sexes, kaempferol and salicylic acid were strongly correlated, indicating their role in tolerance against the metal. The obtained results are an excellent starting point for the practical use of male and female Salix × fragilis L. in areas heavily polluted with Cu or Zn and exposed to drought, for the purpose of their recultivation.

Toxic effects of atmospheric deposition in mining areas on wheat seedlings.

Storage and transportation of coal, as well as operation of coal-fired power plants, produce amounts of metallic exhaust that may lead to different atmospheric environment in the overlapped areas of farmland and coal resource (OAFCR) environment. To investigate the effects of different atmospheric environment in the OAFCR region (north of Xuzhou) on wheat seedlings (AK-58), a box experiment was conducted and compared to an area far from the OAFCR (south of Xuzhou). The study revealed that (1) compared to the southern suburb of Xuzhou, the fresh and dry weight, activities of photosynthetic enzymes and POD of wheat seedlings in the OAFCR reduced obviously. (2) Significantly higher levels of Cr, Cd, Pb, Zn, and Cu were found in the shoots and roots of wheat seedlings in the OAFCR, with lower transfer factor for heavy metals (except Cd and As) in comparison to those in the southern suburb. And the bioconcentration factors of heavy metals (except As) in wheat seedlings in the OAFCR were significantly higher. (3) Nearly 90% of heavy metals (Pb, Cu, Cd, Zn, and Cr) absorbed by wheat were stored in cell walls and soluble fractions, with significantly higher contents of Cu and Cr in wheat seedlings' cell walls and higher contents of Pb, Zn, and Cd in soluble components found in the OAFCR. Our results showed that atmospheric deposition in the mining area has a certain toxic effect on wheat seedlings, and this study provides a theoretical basis for OAFCR crop toxicity management.

Economic Aspects of Mechanical Pre-Treatment’s Role in Precious Metals Recovery from Electronic Waste

Printed circuit boards (PCBs) make up 3 to 5% of all electronic waste. The metal content of spent PCBs can reach 40%. They usually contain valuable metals, such as Ag, Au, and Pd, as well as other metals such as Cu, Sn, Pb, Cd, Cr, Zn, Ni, and Mn. However, the metallic part of a whole PCB is 40–60% including the Cu layers between the fiberglass–polymer layers. The paper describes the economics of the valuable metal (Ag, Au, Pd)-containing concentrate preparation from a raw PCB. We considered the influence of the pre-treatment method of PCBs before the extraction of valuable metals on the extraction self-cost change. The disintegration method is based on the high-energy impact of the particles of the material to be ground, thus causing the separation of the metallic components of the PCB. In the course of the work, single and double direct grinding using the method of disintegration was studied. For the calculation, the test batch of 10,000 kg of two types of PCB was taken for estimation of the self costs and potential profit in the case of complete valuable metals (Ag, Au, Pd) plus Cu extraction. It was shown that from 10,000 kg of studied PCB, it is possible to obtain 1144 and 1644 kg of metal-rich concentrate, which should be further subjected to electro-hydrochlorination for metals leaching. The novelty of this research lies in the fact that a technical and economic analysis has been carried out on a newly developed combined technology for processing electronic waste. This included mechanical processing and electrochemical leaching with the help of the active chlorine that is formed in situ. The real (not specially selected or prepared) waste PCBs were used for the process’s economical efficiency evaluation. The main findings showed that despite the high content of Cu in the studied PCBs, the commercial value was insignificant in relation to the total income from the Ag, Au, and Pd sale. A correlation was established between the self-cost decrease after separative disintegration of PCBs by metal content increase (by specific metals such as Au, Ag, Pd, and Cu) with the metal potential yield after extraction.

Hydrothermal synthesis of Cu-substituted Ni ferrites: Structural, morphological, and magnetic properties

Cu-substituted Ni ferrite systems are produced following a hydrothermal synthetic route carried out at relatively mild conditions (i.e., below 200 °C). Different degrees of substitution were investigated, ranging from bare Ni ferrite to a complete Cu-substituted system (by replacing 100% of Ni with Cu). Morphological and structural characterisations point out that the introduction of Cu in the Ni ferrite (below 50% substitution) causes a gradual reduction of the average diameter of the ferrite polyhedral nanoparticles maintaining the Ni ferrite structure. At higher content of Cu, instead, the morphology evolves toward the co-presence of iron oxides (magnetite and hematite) and copper oxide (tenorite), without the formation of bare Cu ferrite. The partially substituted Ni ferrite nanomaterials exhibit a mostly superparamagnetic behaviour in all samples, registering a reduction of the values of magnetisation saturation by increasing the Cu content. Transmission Mössbauer spectroscopy performed on these nanomaterials evidenced a gradual lowering of the Fe fraction occupying the octahedral sites and a consequent increment of the Fe fraction in the tetrahedral sites. Quantitative analysis confirms the gradual reduction of the Ni content within the ferrite samples, coupled with the opposite increment of the Cu content, whereas the Fe content is lower in the case of Ni75-Cu25 sample. This particular behaviour can be associated with the influence of Cu substitution in the Ni ferrite structure, with preferential replacement of Fe from the octahedral B-sites toward the tetrahedral A-sites.

Electrical, morphological, optical and mathematical simulations equations studies in CAZO, CZO, AZO and ZNO films

Purpose In this paper, it can be seen from AFM images of the as-deposited ZnO and CZO films, and the particle size and shape are not clear, while by increasing annealing temperature, they become distinguishable. By increasing temperature to 600°C, ZnO and CZO, CAZO and aluminum-doped zinc oxide (AZO) films particles became almost spherical. Due to high content of Cu in CZO target, and of Al in AZO target which was 5% weight ratio, doping plays a great role in the subject. Therefore, the annealing processing strongly affect the size and the shape of nanoparticles. Design/methodology/approach In this paper, the authors tried to study, in detail, nobel optical characterizations of ZnO films doped by transition metals in different annealing temperature. The authors found that the values of skin depth, optical density, electron–phonon interaction, steepness parameter, band tail width, direct and indirect carriers transitions and the dissipation factor, free carriers density and roughness of films affect the optical properties, especially the optical absorptions of ZnO films doped by transition metals. Also these properties were affected by annealing temperatures. The authors also found that topography characterizations strongly were affected by these parameters. Findings The CZO films have maximum value of coordination number ß, with considering NC = 4, Za = 2, Ne = 8. The CZO films annealed at 500 °C have maximum value of optical density. The as-deposited CAZO films have maximum value of steepness parameters in about of 0.13 eV. The as-deposited AZO films have maximum value of dispersion energy Ed in about of 5.75 eV. Optical gap and disordering energy plots of films can be fitted by linear relationships Eg = 0.49 + 0.2 EU and Eg = 0.52 + 0.5 EU, respectively. Originality/value With considering Nc = 4, Za = 2, Ne = 8 for ZnO films, coordination number ß has maximum value of 0.198. CZO nanocomposites films annealed at 500°C have maximum value of optical density. Different linear fitting of ln (α) for films were obtained as y = Ax + B where 5<A < 17 and 5<B < 12. As-deposited CAZO nanocomposites films have minimum value of electron phonon interaction in about of 4.91 eV. Optical gap and disordering energy plots can be fitted by linear relationships Eg = 0.49 + 0.2 EU and Eg = 0.52 + 0.5 EU for as-deposited films and films annealed at 500°C, respectively. Steepness parameters of as-deposited CAZO nanocomposites films have maximum value of 0.13 eV. Dispersion energy Ed for as-deposited AZO nanocomposites films has maximum value of 5.75 eV.

Geochemical diversity and tectonic relationships in monogenetic volcanic fields: A case study of the Sredinny Range, Kamchatka

We report, here, the composition and KAr ages of a representative collection of volcanic rocks that erupted within three monogenetic volcanic fields in the active fault zone of the Sredinny Range of Kamchatka: Tigilsky Dol, Mount Oxi massif and Anaunsky Dol. The studied rocks display a wide range of compositions (medium-K, moderate-Mg, high-K, high-Ti and high-Mg basalts, and high-LREE picrobasalts); the high-Mg varieties are confined to faults. Five main periods of volcanic activity were investigated, 4.3–3, 2, 1.5, 1 Ma and from 0.3 to <0.05 Ma. Primitive lavas first emerged on the surface at 3.5 Ma. There was a massive outpouring of high-Mg lavas at 1.5–1 and 0.3 Ma, which could have been related to the formation of the fault zone. This is the first report of rocks in Kamchatka with a high-LREE picrobasaltic composition (1.5 Ma). The Fo content of the olivine phenocrysts reaches 93.2 mol%, which is the highest value known for Quaternary Kamchatka basalts. A very heterogeneous source, even for individual eruptions is indicated by the minor element contents in the olivine (Ni, Mn and Ca); Cr-spinel – olivine paragenesis show that all the rocks studied crystallized in the same temperature range (1111–1292 °C), whereas the oxygen fugacity for the different samples varied from ΔQFM +0.7 to +2.0 log. units. A melt inclusion study showed that the Mg basalts of the Mt. Oxi massif and the high-LREE picrobasalts of Tigilsky Dol had different fluid sources that were enriched and depleted in water and Cl, respectively. We argue that the fluid source for the Mt. Oxi massif was likely the remains of the Pacific slab under the Sredinny Range, whereas, for the high-LREE picrobasalts of Tigilsky Dol, it was the lithospheric lithologies. The low content of S and high content of Cu in the oxidized high-LREE basalts provide additional evidence that they originated from the re-melting of sulfur-poor lithospheric lithologies. Both the fault zone and the lithosphere re-activation in the region are likely linked to the regional stress field.

Trace elements exposure through the dietary intake of fruits and vegetables collected from a divisional city of Bangladesh: Human health implications

BackgroundDietary exposure is the main source of bioaccumulation of trace elements through contaminated fruits and vegetables, which are rich sources of vitamins and minerals, but also toxic elements, which harm our health and well-being. ObjectivesThis study focused on human health nutrition and risks associated with the cancer-causing and non-cancerous trace elements in commonly available winter fruits and vegetables collected from Mymensingh divisional city markets. MethodsSix locally available fruits (viz. pineapple, guava, hog plum, water chestnut, banana, Indian olive) and six seasonal vegetables (viz. red amaranth, radish leaves, brinjal, bottle gourd, radish, and carrot) were collected. The atomic absorption spectrophotometer was used to determine the contents of Zn, Fe, Mn, Cu, Pb, Cr, and Cd. Target Hazard Quotient (THQ), Hazard Index (HI), and Cumulative Incremental Lifetime Cancer Risk (∑ILCR) were calculated to estimate non-cancer and cancer health risks. ResultsAll trace element contents were higher in vegetables than in fruits except Cu. Chromium contents were below the detectable limit for all fruits and vegetables. The highest amounts of Zn (10.54 µg g−1 fresh wt.), Fe (68.75 µg g−1 fresh wt.) and Mn (55.65 µg g−1 fresh wt.) were found in radish leaves. On the other hand, the maximum amounts of Pb (0.388 µg g−1 fresh wt.) and Cd (0.180 µg g−1 fresh wt.) were found in red amaranth, while the highest content of Cu (5.67 µg g−1 fresh wt.) was determined from banana. The calculated HI was <1 in every case except red amaranth suggesting none of the fruit and other vegetable samples poses individual non-cancerous risk after consumption. On the other hand, the measured ILCR values for Cd for both males and females ranged from 1.51E-04 to 6.45E-03 and 2.12E-04 to 9.03E-03, respectively, indicating cancer risk in all fruit and vegetable samples, either individually or cumulatively. ConclusionThe locally available fruits and vegetables of the Mymensingh divisional city area posed significant human health risks. However, regular monitoring of toxic metal contents is necessary to ensure the food safety of locally grown indigenous fruits and vegetables for the city dwellers.

Determination of metal contents in some green leafy vegetables in Marmara region of Turkey

This study focused on the analysis of mineral and heavy metal contents of spinach, lettuce and parsley samples in different regions to investigate the risks of chronic exposure to heavy metal contamination. After the microwave digestion process, the metal contents of the samples (Na, Mg, Al, P, K, Ca, Fe, Cu, Zn, As, Se, Cd, Sn, Hg, Pb) were determined with the ICP-MS. Two parallel analysis samples were prepared from each sample, analyzed three times, and the mean values of the analyzes performed were reported. From the analysis, the order of finding heavy metals in the samples is Cu > Pb > Cd > As > Sn > Hg. The results were evaluated statistically and Cu, Pb, Cd, As and Sn values were found high in spinach samples (p < 0.05). According to the results of the analysis; the samples with the highest content of Cu, Pb and Cd in spinach samples are samples taken from Tekirdağ (5.1 ± 0.3 mg/kg), Edirne (0.106 ± 0.007 mg/kg) and Tekirdağ (0.080 ± 0.004 mg/kg), respectively. One of the important reasons for this is the increase in industrial areas in those regions. The results were compared with the certified reference materials, the quantities of analytes were determined to be compatible with the certificate values and the results of the analysis were proved to be correct.

Effect of Cu content on central-segregation composition and mechanical properties of Al–Mg–Si alloys produced by twin-roll casting

Dissolving the inherent central segregation is critical to improve the performance of twin-roll casting (TRC) aluminum strips. In this study, we investigated the effects of Cu content (0.8, 1.2, and 1.6 wt%) on the central-segregation composition and mechanical properties of TRC Al–0.8Mg–1.0Si alloys. Cu promoted the segregation-phase transformation from the higher-melting-temperature Mg2Si phase to the lower-melting-temperature Cu-containing phases (Q-AlCuMgSi and θ-Al2Cu), resulting in an easier dissolution of central segregation. Therefore, the segregation of 0.8 and 1.2 wt% Cu alloys was almost dissolved following cold rolling and solution treatment compared to Cu-free alloys. However, after a higher content of Cu (1.6 wt%) was added, the segregation became too severe to dissolve. After modifying with 1.2 wt% Cu, the yield strength (YS) of the TRC alloy increased from ∼306 to 335 MPa, and the elongation was increased from ∼13 to 17%. The contribution of solution strengthening and increasing volume fraction of precipitates results in the strengthening effect of Cu. Meanwhile, the dissolution of segregated phases is also advantageous for solution and precipitation strengthening. This study could lead to the development of a simple method to dissolve TRC central segregation and produce TRC Al–Mg–Si alloys with excellent performance.

Relationships among Physicochemical, Microbiological, and Parasitological Parameters, Ecotoxicity, and Biochemical Methane Potential of Pig Slurry

Background: Pig slurry can negatively impact on the environmental, animal, and human health. Knowing the relationship between the organic and inorganic loads, pathogens, and toxicity allows identifying the main parameters to be removed or treated before final disposal. The aim of this study was to evaluate the relationships between the physicochemical properties, microbiological, and parasitological content, ecotoxicological effects, and biochemical methane potential (BMP) of pig slurries. Methods: Ten pig slurry samples at two production stages were characterized and a BMP test at two substrate/inoculum (S/I) ratios was conducted to compare the methane yields. Results: We found high content of Cu, Zn, quaternary ammonium, pathogenic microorganisms (E. coli and Salmonella), and parasites (Trichuris and Trichostrongylus). Toxicity on lettuce, radish, and Daphnia was observed with a slurry concentration greater than 1.35%. Positive correlations were found between toxicity on Daphnia and chemical oxygen demand (COD), sulfate, Zn, and Cu, as well as between phytotoxicity and COD, NH4, Na, K, and conductivity. The lowest S/I ratio showed 13% more methane yield. It was associated with high removals of COD and volatile fatty acids. Conclusions: We recommend using a low S/I ratio to treat pig slurry as it improves the efficiency of the anaerobic process.

Catalytic ignition of CO over CuCeZr based catalysts: New insights into the support effects and reaction pathways

Self-sustained catalytic combustion is a promising strategy to remove CO from the off-gas produced during steelmaking, where the potential catalysts are bulk copper-cerium-zirconium mixed oxides or those supported on TiO2 or ZSM-5 substrates. In this study, the effects of the catalyst support on the CO catalytic ignition performance and reaction pathways were investigated by FTIR coupled with a novel in-situ cell, together with the state-of-the-art characterization techniques. The Infrared (IR) transmission cell equipped with a magnetically driven system, could effectively prevent overlaps between active intermediate peaks (Cu+-CO and Cu+(CO)2) and gaseous CO peaks. The Cu+ cations located at the phase interface are the main active sites. The Cu and Ce interactions lead to the formation of solid solutions of CuCe0.75Zr0.25Oδ (CuCeZr). The monocarbonyls [Cu+-CO] are the dominant species during CO oxidation, and the vacancies in the solid solutions are occupied by oxygen, accelerating the oxygen cycle. The TiO2 or ZSM-5 supports promote copper dispersion over CuCe0.75Zr0.25Oδ/TiO2 (CuCeZr/T) and CuCe0.75Zr0.25Oδ/ZSM-5 (CuCeZr/Z) catalysts, which can be attributed to their high surface areas (168.2 and 346.3 m2/g, respectively), while the Cu-Ce interactions are less relevant. Hence, CO oxidation mainly occurs at the phase interface between copper oxide and TiO2/ZSM-5. Dicarbonyls [Cu+(CO)2] are the main intermediates for the CuCeZr/T and CuCeZr/Z catalysts, and the Cu2+ species are reduced to form dicarbonyls that also take part in the oxidation process. Although a well copper dispersion enhances the activity of individual copper sites on the CuCeZr/T and CuCeZr/Z catalysts, considering the redshift of the carbonyl bands and the increase in CO adsorption, the close interactions and high contents of Cu and Ce favor the local accumulation of heat and mass transfer over bulk CuCeZr, leading to the ignition of CO at low temperatures.

Processing and properties of powder metallurgy Ti-Cu-Nb alloys

Binary Ti-Cu and Ti-Nb alloys have been extensively studied for biomedical applications, but the potential of ternary Ti-Cu-Nb alloys, where the combined benefits of adding Cu and Nb on the performance of biomedical Ti alloys is harvested, has not been fully exploited. Therefore, this study aims to investigate the processing and properties of Ti-Cu-Nb alloys obtained via powder metallurgy. Independently of their actual chemistry, the studied Ti-Cu-Nb alloys are characterised by a lamellar microstructure, which is refined by the incremental addition of Cu+Nb, and a eutectoid substructure is formed for sufficiently high contents of Cu. The balance between slightly higher residual porosity and the microstructural changes, including the stabilisation of a greater amount of β phase, a lamellar structure with refined features, and the precipitation of the Ti2Cu intermetallic phase, leads to a monotonic linear increment of the resistance to plastic deformation. However, the ductility initially increases for small additions of Cu+Nb and subsequently decreases due to the change in failure mode induced by the progressively higher impact of the residual pores. The studied Ti-Cu-Nb alloys share the same strengthening mechanism and have better strength/ductility pairs with respect to binary Ti-Cu and Ti-Nb alloys and better elongation compared to cast Ti-Cu-Nb alloys.

EFFECTS OF FERTILIZATION AND IRRIGATION LEVELS ON PHYTOREMEDIATIONPROPERTIES OF PERENNIAL RYEGRASS

The experiment was set up in the greenhouse of Faculty of Agriculture, University of Belgrade with the aim of investigating potential of perennial ryegrass (Loliumperennial L.) to grow on substrates of exceptionally unfavorable characteristics. Tailings, characterized by very poor physical and chemical properties and deficiency in nutrients were used as substrate. The research examined effects of three different fertilizers and two irrigation levels on plant growth and assimilation of Cu and Cd. There were statistically highly significant differences in plant height between plants treated with different fertilizers. Plants treated with organic fertilizer were tallest at 45.8 cm, while the plants treated with mineral fertilizer were shortest at 22.5 cm. Amounts of the assimilated metals varied between different type of fertilizers. The highest content of Cu, about 75 mg kg-1 was recorded in plants treated with mineral fertilizer and irrigated moderately while the lowest concentrations of about 30 mg kg-1were measured in the same plants after the first cutting. There were no differences among plants treated with organic fertilizers in Cu amounts,under two irrigation levels. The second cutting showed a small increase in the assimilated amounts of Cu. Highest Cd concentration of 2.7 mg kg-1 was recorded in the plants treated with combination of both organic and mineral fertilizers.

Comparison of carcass traits and nutritional profile in two different broiler-type duck lines.

Cherry Valley ducks (CVDs) and White Kaiya ducks (WKDs) are judged to be fast- and slow-growing lines, respectively. To investigate the carcass traits and nutritional profile at their marketable ages, 12 birds (38 days for CVDs, n = 6; 56 days for WKDs, n = 6) were randomly selected and slaughtered. Indicators such as breast muscle weight, shear force, and proximate composition were comprehensively detected. Although the carcass and breast muscle weight in WKDs were significantly lower, remarkably higher intramuscular fat and tenderness and less moisture content were observed in WKDs. Besides, WKDs contained higher contents of Cu, Zn, and Ca, whereas CVDs contained higher leucine (Leu) and histidine (His) compositions (P < 0.01). Moreover, higher monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) along with lower saturated fatty acids (SFAs) were detected in WKDs (P < 0.01). Taken together, despite light carcass and breast muscle weight, WKDs had advantages in nutritional compositions except for amino acid constituents, including intramuscular fat, MUFAs, and PUFAs, as well as Cu, Zn, and Ca. These data would not only provide genetic resources for breeding new duck lines but also offer a useful reference for making decisions on high-nutrient meat consumption.

Impact of the Initial Phase Composition of Alloys on the Effects Manifested by Yield Sites That Occur on Sheet Aluminum Alloys Subjected to Impact-Oscillatory Loading

The impact of the initial phase composition of alloys was evaluated, in particular, the content of Cu, Mn, and Mg in aluminum alloys D16ChATW, 2024-T351 and aluminum alloy T, which in its physical and mechanical characteristics is close to alloy 6013. The impact was evaluated on the effects manifested by yield sites that occur on aluminum alloys that were subject to the dynamic non-equilibrium processes (DNPs) at the expense of impact-oscillatory loading of different intensities under conditions of static tensioning, The one-time DNP, to which the investigated aluminum alloys were subjected at the pre-set levels of elastic strain followed by static tensioning, was found to cause yield sites formation. This is due to self-organization of the alloy structure, which contributes to alloy plasticization. The initial phase alloys composition impact on the yield sites, which occurs when impulse energy of a different intensity is applied to the alloys, was analyzed. The specimens from the aluminum alloys undergoing DNPs of the same level were compared. This made it possible to conclude that alloys D16ChATW and 2024-T351, which have a higher content of Cu, Mn, and Mg, have longer yield sites upon subsequent static tensioning. On the basis of the experimental results, in particular, physical studies, the authors derived a physical and mathematical model of the yield sites that appear after DNPs.