Mixture Of Zinc Research Articles

Structural and optical properties of TZO thin films

In this paper, the synthesis route and growth mechanism of ZnO nanowhiskers and multipods are investigated. A simple chemical deposition route is used to synthesize tin doped zinc oxide (TZO) nanostructures using a horizontal quartz furnace. To study the effect of tin doping on the morphology of ZnO thin film, nanostructures with different morphologies and sizes were grown on silicon wafers and ITO substrates using thermal evaporation of a mixture of zinc, tin, and graphite powders at 1000 °C in a pure oxygen atmosphere. Structural studies of the synthesized ZnO nanostructures were done by means of XRD, SEM, and HRTEM. An XRD graph confirmed the formation of a pure ZnO phase. The SEM and HRTEM images exhibited nanowhiskers with dimensions of an average width of 100 nm and a few micrometers in length. The photoluminescent properties of these structures were also investigated where it shows strong blue-green emission at room temperature for the samples doped with tin.

Synthesis of Zn‐doped talc in hydrothermal atmosphere

Zn‐doped talc were synthesized under hydrothermal conditions at constant reaction time and pressure of 160 hours and 2 kbar respectively, at three different temperatures (300, 500 and 650 °C) with pH‐values of 5 and 7. The starting materials and run products were characterized by X‐ray powder diffraction (XRPD), scanning electron microscopy with annexed energy‐dispersive spectrometry (SEM‐EDS), differential scanning calorimetry thermogravimetric analysis (DSC‐TG) and Fourier transform infrared (FT‐IR). The results showed that the temperature, pH‐value of the reaction mixture and amount of zinc in the starting mixture affected the growth of the Zn‐doped talc. When synthesized at low temperature talc presents low crystallinity, flawed morphology but higher content in zinc in its lattice. A thermal treatment at, or above 500 °C allowed a significant flaw reduction in talc morphology, a higher crystallinity and a lower content in dopant. When large amounts of Zn were present in the starting mixtures, Zn‐doped talc grew small in size and poorly shaped. The effect of Zn doping on some chemical/physical characteristics of the synthesized talc was also discussed.

Running-in of repaired engines using friction modifiers

Purpose – The paper aims to present a new friction modifier (mixture of zinc and copper oleates) proper for industrial running-in of repaired engines. Design/methodology/approach – The method of comparison was used for testing the offered friction modifier, a market product “Renom Engine” and a blank sample of motor oil as an etalon. Running-in time has been established. The mechanical losses change and the relevant coefficients have been determined. Data of the bearings wear have been included. Findings – The benefit of the metal oleates and Renom Engine usage as friction modifiers has been proved. Time for industrial cold running-in of repaired engines decreases by around 20 per cent when friction modifiers are used in comparison with the etalon oil. The coefficient of the mechanical losses reduction at running-in with friction modifiers is higher than the coefficient for the etalon oil. The higher coefficient values indicate that the running-in of the working surfaces occurs more intensively and for a shorter period of time. Lower wear of the bearings is combined with smaller roughness of the friction surface, which secures higher quality of the surfaces run-in with the friction modifiers and greater capacity by around 30 per cent. Originality/value – This study introduces a new friction modifier for industrial running-in of repaired engines. It would be of interest to the customers and manufacturers of oil additives.

The Cross & the Crucible: The Production of Carolingian Disc Brooches as Objects of Religious Exchange?

In this article, aspects of the production and exchange of Carolingian/Ottonian disc brooches are examined through an analysis of 281 brooches selected from collections across The Netherlands. The composition of the brooches was measured with a Hand Held-XRF device and the results showed a sharp deviation from the alloys seen in brooches from earlier periods. The results across all geographic areas consisted of a mixture of copper, zinc and lead, but no tin. If recycling practices were present in the making of these brooches, then you might expect an element of tin to enter the mixture, as bronze items entered the alloy-recycling stream. But this appears not to be the case. This consistency rules out production by travelling merchants, or at domestic households and primitive workshops. The results suggest that production was more likely organised on a regional or even super regional scale. An analysis of production at royal estates, emporia and the great abbeys found the latter to be the most likely source of these objects. Furthermore, the Christian nature of these brooches, if produced within monastic centres, may have imbued them with religious meaning, allow for a fresh interpretation of their methods of exchange.

Synthesis, characterization, and crystal structure of two zinc(II) complexes with a Schiff base derived from amantadine

By condensation of amantadine and 4-methoxysalicylaldehyde a new Schiff base HL was synthesized. A mixture of HL and zinc(II) chloride in an alcoholic medium leads to [Zn(HL)2Cl2] (1). However, the same reactants gave another different complex (ZnL2) (2) in the presence of NaOH. The two complexes were characterized by IR, 1H NMR, elemental analysis, molar conductance, and single-crystal X-ray diffraction. X-ray diffraction analysis reveals that complex 1 crystallizes in the triclinic system, Pī space group; each asymmetric unit consists of one zinc(II), two HL, and two chlorides. The tetra coordination of central zinc is attained by two chlorides and two oxygens from the Schiff base, forming a distorted tetrahedral geometry. Complex 2 crystallizes in the monoclinic system, P21/c space group; each asymmetric unit consists of one zinc(II) and two L. The tetra coordination of central zinc is attained by two nitrogens and two oxygens from the Schiff base, forming a distorted tetrahedral geometry.

Influence of gaseous atmosphere during a thermal process for recovery of manganese and zinc from spent batteries

The aim of the work is the recovery by thermal treatment of manganese and zinc from a mixture of zinc–carbon and alkaline spent batteries, due to the different phase change temperatures of the metals. Activated charcoal, as a reductant of the zinc-bearing phases to metallic Zn, was added to the mixture that was heated in different atmospheres (air, nitrogen, carbon dioxide) at different temperatures and residence times. Characterization of the mixture and of the residues of thermal treatment was carried out by chemical analysis, thermogravimetric and differential thermal analysis, scanning electron microscope and X-ray diffraction and allowed to understand the mechanisms of reduction of zinc and to interpret the formation of different compounds during the process. Results show that recovery of 99% of Zn (grade 96%) at 1200 °C and 97% of Zn (grade 99%) at 1000 °C, are achieved in N2 at 30 min residence time. Recovery of Mn at 1200 °C and 30 min residence time was around 90–100% (90% grade). These products are suitable, after refining, for production of new batteries or higher value-added products. The residue of the treatment, enriched in manganese oxide, could be used in the production of iron–manganese alloys.

Global Transcriptome Profiling Reveals Molecular Mechanisms of Metal Tolerance in a Chronically Exposed Wild Population of Brown Trout

Worldwide, a number of viable populations of fish are found in environments heavily contaminated with metals, including brown trout (Salmo trutta) inhabiting the River Hayle in South-West of England. This population is chronically exposed to a water-borne mixture of metals, including copper and zinc, at concentrations lethal to naïve fish. We aimed to investigate the molecular mechanisms employed by the River Hayle brown trout to tolerate high metal concentrations. To achieve this, we combined tissue metal analysis with whole-transcriptome profiling using RNA-seq on an Illumina platform. Metal concentrations in the Hayle trout, compared to fish from a relatively unimpacted river, were significantly increased in the gills, liver and kidney (63-, 34- and 19-fold respectively), but not the gut. This confirms that these fish can tolerate considerable metal accumulation, highlighting the importance of these tissues in metal uptake (gill), storage and detoxification (liver, kidney). We sequenced, assembled and annotated the brown trout transcriptome using a de novo approach. Subsequent gene expression analysis identified 998 differentially expressed transcripts and functional analysis revealed that metal- and ion-homeostasis pathways are likely to be the most important mechanisms contributing to the metal tolerance exhibited by this population.

Heavy Metal Accumulation in Fish of Ivo River, Ishiagu Nigeria

Heavy metal accumulation in fish from Ivo River at Ishiagu was carried out to assess the level of Pb and Zn concentrations. Five healthy fish were collected and divided into groups for this assessment using group (I) as the primary control. The other four groups (II-IV) were exposure to single and joint sublather concentration for 150 h and 17 days, respectively. The level of heavy metal concentrations in the selected fish were determined using Chromosomal Aberration Test (CAT) induced in the branchial arches or gill arches in the fish. From the result, the groups (II-IV) were significantly higher (p<0.05) than the control (I) in their chromosomal aberration abundance. While binary mixture of lead and zinc in equimolar concentration revealed significantly lower (p<0.05) incidence of chromosomal aberrations compared to group II-III containing the individual graded metal (lead and zinc) acting alone. Biological risk assessment based on chromosome morphology in aberration test revealed the mutagenicity of lead, zinc and their binary mixture. The single actions of the two metals were evidently observed to be significantly higher in toxicity than the equimolar mixture in chromosomal aberration abundance. There is high indication that lead and zinc would pose greater danger to health for the Ishiagu community if there is continuous consumption of fish from the river over a period of time.

EFFECT OF POLYMER SEED COATING WITH MICRONUTRIENTS ON SOYBEANS IN SOUTHEASTERN COASTAL PLAINS

Polymer seed coating with micronutrients may affect soybean (Glycine max (L.) Merr) growth and yields under dryland conditions. The objective of t his study was to determine the effect of two seed application rates (265 and 395 mL 100 kg seeds -1 ) of polymer based mixture of Copper (Cu), Manganese (Mn) and Zinc (Zn) micronutrients on dryland soybeans near Blackville, SC from 2011 to 2012. Soybeans were evaluated for plant Normalized Difference Vegetation Index (NDVI), Leaf Area Index (LAI), plant height, seed weight and grain yi elds. Compared to untreated control, polymer seed coating significantly increased grain yields by 8.1 and 14.0% with seed applications at 265 and 395 mL 100 kg seeds -1 , respectively. Plant NDVI improved by 10.5% with a pplication of polymer seed coating treatment at 395 mL 100 kg seeds -1 . Seed coating at 265 and 395 mL 100 kg seeds -1

INFUENCE OF SEED COATING WITH MICRONUTRIENTS ON GROWTH AND YIELD OF WINTER WHEAT IN SOUTHEASTERN COASTAL PLAINS

Polymer seed coating with micronutrients may provide important nutrients during plant growth and impro ve yields. The objective of this study was to determin e the effect of three seed application rates (265, 395 and 530 mL 100 kg seeds -1 ) of polymer based mixture of Copper (Cu), Manganese (Mn) and Zinc (Zn) micronutrients on dryland winter wheat ( Triticum aestivum L.) near Blackville, SC from 2010 to 2012. Compared to untreated control, seed coating signifi cantly increased grain yields by 5.0 and 2.1% with seed applications at 530 and 395 mL 100 kg seeds -1 , respectively. Dry matter yield improved over cont rol by 13.4, 22.6 and 20.7%, N uptake by 13.9, 24.6 and 19 .3% and P in plant biomass by 16.0, 23.3 and 21.3% with seed applications at 265, 395 and 530 mL 100 kg seeds -1 , respectively. Coating application of 265 mL 100 kg seeds -1 increased grain N content by 5.0% compared to control. Grain P uptake was greater with seed application rates of 265 and 395 mL 100 kg see ds -1 (0.415 and 0.399%, respectively) than 530 mL 100 kg seeds -1 (0.385%). Significantly higher grain Cu uptake was observed at rate of 395 mL 100 kg seeds -1

Impact of copper and zinc mixture on bacterial flora of digestive tract of rainbow trout (oncorhynchus mykiss)

AbstractThe effects of 96-hour exposure and within 12 days after exposure to 0.25, 0.125, 0.06 portions of the 96-hour LC50 of CuZn ions mixture on microbiological parameters of rainbow trout digestive tract were studied evaluating quantitative and functional characteristics of bacteria. The extinction of proteolytic bacteria was found in fish affected by 0.25 portion of the 96-hour LC50 of metal mixture. The recovery of proteolytic bacteria was determined in fish exposed to 0.125 and 0.06 portions of the 96-hour LC50 of CuZn ions mixture after 8 days of keeping fish in clean water. The abundance of the investigated functional groups of bacteria was gradually recovering to the control level after 12 days of keeping fish in clean water.

Structural and mechanistic characterization of L-histidinol phosphate phosphatase from the polymerase and histidinol phosphatase family of proteins.

L-Histidinol phosphate phosphatase (HPP) catalyzes the hydrolysis of L-histidinol phosphate to L-histidinol and inorganic phosphate, the penultimate step in the biosynthesis of L-histidine. HPP from the polymerase and histidinol phosphatase (PHP) family of proteins possesses a trinuclear active site and a distorted (β/α)(7)-barrel protein fold. This group of enzymes is closely related to the amidohydrolase superfamily of enzymes. The mechanism of phosphomonoester bond hydrolysis by the PHP family of HPP enzymes was addressed. Recombinant HPP from Lactococcus lactis subsp. lactis that was expressed in Escherichia coli contained a mixture of iron and zinc in the active site and had a catalytic efficiency of ~10(3) M(-1) s(-1). Expression of the protein under iron-free conditions resulted in the production of an enzyme with a 2 order of magnitude improvement in catalytic efficiency and a mixture of zinc and manganese in the active site. Solvent isotope and viscosity effects demonstrated that proton transfer steps and product dissociation steps are not rate-limiting. X-ray structures of HPP were determined with sulfate, L-histidinol phosphate, and a complex of L-histidinol and arsenate bound in the active site. These crystal structures and the catalytic properties of variants were used to identify the structural elements required for catalysis and substrate recognition by the HPP family of enzymes within the amidohydrolase superfamily.

The crystal structure of Ni–Zn co-doped β boron, Ni0.18Zn1.21B34.94

The crystal structure of beta-rhombohedral boron co-doped with nickel and zinc was refined using a single crystal of the composition Ni44.4Zn11.2B44.4 (in at.%) (space group, R3¯m, a=1.10182(2)nm, c=2.40534(5)nm, RF=0.040, residual electron density<1.59e−/Å3). The Ni/Zn ratio of 1:6.5 was determined by electron microprobe analysis. Zn atoms were found to partially occupy atomic sites that have been named E positions in earlier works. A1, D and Dd positions are partially occupied with mixtures of zinc and nickel atoms (Ni:Zn=15.5:84.5). Refinement in the space group R3 was tried to allow for further ordering of the metal atoms but did not result in a better structure description.

Management of Alveolar Osteitis: A Comparative Study of Two-Treatment Techniques

ABSTRACTBackgroundThe traditional method for the management of alveolar osteitis (dry socket) has its shortcomings in clinical dental practice as it takes long duration with frequent visits by the patients for completion of treatment. Objective is to determine the outcome of treatment using two techniques on patients who presented with alveolar osteitis following forceps dental extractions.Materials and MethodsThis is a 3-year prospective study of 42 patients with alveolar osteitis seen at the University of Calabar Teaching Hospital, Nigeria. Following irrigation of the extraction sockets with dilute hydrogen peroxide, the sockets and surrounding gingival tissues were debrided to promote the reestablishment of the blood clot in the radical group, while in the traditional method, they were dressed with gauze impregnated with mixture of zinc oxide/eugenol.ResultsThe age of patients ranged from 14 to 52 years, with the majority between 21 and 40 years (n = 27, 64.2%). There were 24 (57.1%) females and 18 (42.9%) males with a male to female ratio of 1:1.3. More extraction sockets with alveolar osteitis were recorded in the mandible (n = 35, 83.3%) than the maxilla (n = 7, 16.7%); and in both jaws, the molar sockets (76.2%) were predominant.ConclusionThere is reduction in the duration of treatment in the radical group of patients when compared with those treated traditionally. This alternative treatment is safe and reliable and can be utilized by the practitioner who runs a busy clinic to save time. However, randomized controlled clinical trials are needed to validate this new technique.How to cite this articleAnyanechi CE. Management of Alveolar Osteitis: A Comparative Study of Two-Treatment Techniques. J Contemp Dent 2013;3(1):11-14.

Metal Contamination Disturbs Biochemical and Microbial Properties of Calcareous Agricultural Soils of the Mediterranean Area

Mediterranean climate characteristics and carbonate are key factors governing soil heavy-metal accumulation, and low organic matter (OM) content could limit the ability of microbial populations to cope with resulting stress. We studied the effects of metal contamination on a combination of biological parameters in soils having these characteristics. With this aim, soils were spiked with a mixture of cadmium, copper, lead, and zinc, at the two limit values proposed by current European legislation, and incubated for ≤12 months. Then we measured biochemical (phosphatase, urease, β-galactosidase, arylsulfatase, and dehydrogenase activities) and microbial (fungal and bacterial DNA concentration by quantitative polymerase chain reaction) parameters. All of the enzyme activities were strongly affected by metal contamination and showed the following inhibition sequence: phosphatase (30-64 %) < arylsulfatase (38-97 %) ≤ urease (1-100 %) ≤ β-galactosidase (30-100 %) < dehydrogenase (69-100 %). The high variability among soils was attributed to the different proportion of fine mineral fraction, OM, crystalline iron oxides, and divalent cations in soil solution. The decrease of fungal DNA concentration in metal-spiked soils was negligible, whereas the decrease of bacterial DNA was ~1-54 % at the lowest level and 2-69 % at the highest level of contamination. The lowest bacterial DNA decrease occurred in soils with the highest OM, clay, and carbonate contents. Finally, regarding the strong inhibition of the biological parameters measured and the alteration of the fungal/bacterial DNA ratio, we provide strong evidence that disturbance on the system, even within the limiting values of contamination proposed by the current European Directive, could alter key soil processes. These limiting values should be established according to soil characteristics and/or revised when contamination is produced by a mixture of heavy metals.

Combustion synthesis of porous ZnO monoliths for sulfur removal

Highly porous ZnO monoliths are prepared with potential applications as regenerable adsorbents for sulfur removal. ZnS/NaCl composite materials are first obtained by combustion synthesis from mixtures of zinc, sulfur and sodium chloride powders. After NaCl removal by lixiviation with water, they are converted into ZnO by thermal treatment under air. The crystalline structure, the microstructure and the porosity of the resulting monoliths are investigated by X-ray diffraction, scanning electron microscopy and Hg porosimetry. Their evolution after sulfidation–regeneration cycles is also considered.

Thermal treatment for recovery of manganese and zinc from zinc–carbon and alkaline spent batteries

The aim of this paper is the recovery of manganese and zinc from a mixture of zinc–carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn2O3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

Glycine-assisted fabrication of zinc and manganese ferrite nanoparticles

In this research work, we have used a microwave combustion method to synthesize three nanocrystalline ferrites including MnFe2O4, ZnFe2O4 and Mn0.5Zn0.5Fe2O4. For synthesis of these ferrites, a mixture of iron (III) nitrate, zinc and/or manganese nitrate, along with glycine, as fuel, was heated in a microwave oven for a few minutes to afford the required ferrite in pure and quantitative yield. The obtained ferrites were characterized by X-ray powder Diffraction (XRD), and their mean grain size and morphology were determined by the Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopy (TEM) studies. The magnetic properties of the synthesized ferrites were investigated with Vibrating Sample Magnetometry (VSM), and their hysteresis loops were obtained. The specific surface area and pore size distributions of the samples were also obtained using Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) methods, respectively.

Simultaneous growth of ZnSe cactus-like structures and novel microflowers of selenium

We report here the simultaneous growth of ZnSe cactus-like structures with nanorods emerging from their surface and selenium microflowers using Zn and Se powders as precursors. ZnSe cactuses were obtained by solid state chemical reaction whereas selenium microflowers were obtained by thermal evaporation and condensation process. ZnSe cactuses consist of spheres with diameter range 2–3 μm having nanorods with diameter in the range 60–90 nm on the exterior surface. The mixture of zinc and selenium powders with few drops of aqueous ammonia loaded in semicircular long alumina boat was heated inside horizontal tube furnace at 500 °C for 180 min under ammonia atmosphere. The structural, compositional and morphological characterizations have been performed by means of Scanning Electron Microscope (SEM), the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD). Room temperature photoluminescence (PL) measurement of as-synthesized products show two intensive peaks centered at 404 nm and 427 nm (2.85 eV), which are attributed to the band edge emission of ZnSe. These two strong emission bands are blue shifted; this blue shift is because of quantum size confinement effect of nanostructures. A very weak peak centered at 464 nm (2.67 eV) is also observed in our sample which is exactly equivalent to the peak associated with the bulk ZnSe, and is attributed to near band edge emission (NBE) for the ZnSe nanostructures.

Surface alloying of AZ91E alloy by Al–Zn packed powder diffusion coating

A new surface coating technique, namely packed powder diffusion coating (PPDC), for AZ91E magnesium alloy is reported. This new technique uses a powder mixture of aluminium and zinc as diffusion source and produces uniform and thick coatings at temperatures below 420°C. Experimental results showed that zinc in the powder mixture significantly promotes the formation of intermetallic layers on the surface of the magnesium alloy at process temperatures between 350°C and 413°C, which is more than 50°C lower than the previously reported processes. Depending on the temperature and the Zn-content in the powder, X-ray diffraction analysis identified three intermetallic phases and Mg(Al, Zn) solid solution that consist of the surface alloyed layer. The intermetallic compounds are τ-Mg32(Al,Zn)49, φ-Al5Mg11Zn4 and β-Mg17(Al,Zn)12. The hardness of the over 500μm thick surface alloyed layers is up to four times higher than the substrate. Both the β-Mg17(Al,Zn)12 phase and the τ-Mg32(Al,Zn)49 phase show one to two order magnitude higher corrosion resistance than the α-phase (solid solution) and the φ-Al5Mg11Zn4 phase in 5% NaCl solution. A process parameter window for the layer thickness as well as a schematic model for the formation of the layer is proposed. The PPDC process is a promising technique that provides effective protection of AZ91E alloy from both wear and corrosion.