Search results for: copper compound

Authors: Ammar Benamrani

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This work investigates the equation of state parameters, elastic constants, and several other physical properties of (B2-type) Yttrium-Copper (YCu) rare earth intermetallic compound using the projected augmented wave (PAW) pseudopotentials method as implemented in the Quantum Espresso code. Using both the local density approximation (LDA) and the generalized gradient approximation (GGA), the finding of this research on the lattice parameter of YCu intermetallic compound agree very well with the experimental ones. The obtained results of the elastic constants and the Debye temperature are also in general in good agreement compared to the theoretical ones reported previously in literature. Furthermore, several thermodynamic properties of YCu intermetallic compound have been studied using quasi-harmonic approximations (QHA). The calculated data on the thermodynamic properties shows that the free energy and both isothermal and adiabatic bulk moduli decrease gradually with increasing of the temperature, while all other thermodynamic quantities increase with the temperature.

Keywords: Yttrium-Copper intermetallic compound, thermo_pw package, elastic constants, thermodynamic properties

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Authors: I. Siti Rabiatull Aisha, A. Ourdjini, O. Saliza Azlina

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The aim of this paper is to study the effectiveness of bismuth addition in the solder alloy to retard the intermetallic compound formation and growth. In this study, three categories of solders such as Sn-4Ag-xCu (x = 0.5, 0.7, 1.0) and Sn-4Ag-0.5Cu-xBi (x = 0.1, 0.2, 0.4) were used. Ni/Au surface finish substrates were dipped into the molten solder at a temperature of 180-190 ^oC and allowed to cool at room temperature. The intermetallic compound (IMCs) were subjected to the characterization in terms of composition and morphology. The IMC phases were identified by energy dispersive x-ray (EDX), whereas the optical microscope and scanning electron microscopy (SEM) were used to observe microstructure evolution of the solder joint. The results clearly showed that copper concentration dependency was high during the reflow stage. Besides, only Ni₃Sn₄ and Ni₃Sn₂ were detected for all copper concentrations. The addition of Bi was found to have no significant effect on the type of IMCs formed, but yet the grain became further refined.

Keywords: Bismuth addition, intermetallic compound, composition, morphology

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Authors: Turan Çalban, Fatih Sevim, Oral Laçin

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In this study, the precipitation conditions of Chevreul’s salt were evaluated. The structure of Chevreul’s salt was examined by considering the previous studies. Thermodynamically, the most important precipitation parameters were pH, temperature, and sulphite-copper(II) ratio. The amount of Chevreul’s salt increased with increasing the temperature and sulphite-copper(II) ratio at the certain range, while it increased with decreasing the pH value at the chosen range. The best solution medium for recovery of Chevreul’s salt is sulphur dioxide gas-water system. Moreover, the soluble sulphite salts are used as efficient precipitating reagents. Chevreul’s salt is generally used to produce the highly pure copper powders from synthetic copper sulphate solutions and impure leach solutions. When the pH of the initial ammoniacal solution is greater than 8.5, ammonia in the medium is not free, and Chevreul’s salt from solution does not precipitate. In contrast, copper ammonium sulphide is precipitated. The pH of the initial solution containing ammonia for precipitating of Chevreul’s salt must be less than 8.5.

Keywords: Chevreul's salt, production, copper sulfites, copper compound

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Authors: Zeinab Sanaee, Hossein Jafaripour

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Copper is an excellent conductive material that is widely used in the energy devices such as Lithium-ion batteries and supercapacitors as the current collector. On the other hand, copper oxide nanowires have been used in these applications as potential electrode material. In this paper, nanowires of Copper and Copper oxide have been synthesized through a simple and time and cost-effective approach. The thermally grown Copper oxide nanowires have been converted into Copper nanowires through annealing in the Hydrogen atmosphere in a DC-PECVD system. To have a proper Copper nanostructure formation, an Au nanolayer was coated on the surface of Copper oxide nanowires. The results show the successful achievement of Copper nanowires without deformation or cracking. These structures have a great potential for Lithium-ion batteries and supercapacitors.

Keywords: Copper, Copper oxide, nanowires, Hydrogen annealing, Lithium ion battery

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Authors: Turan Çalban, Oral Laçin, Abdüsselam Kurtbaş

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The experimental production methods Chevreul’s salt being a intermediate stage product for copper recovery were investigated by dealing with the articles written on this topic. Chevreul’s salt, Cu2SO3.CuSO3.2H2O, being a mixed valence copper sulphite compound has been obtained by using different methods and reagents. Chevreul’s salt has a intense brick-red color. It is a highly stable and expensive salt. The production of Chevreul’s salt plays a key role in hiydrometallurgy. In recent years, researchs on this compound have been intensified. Silva et al. reported that this salt is thermally stable up to 200oC. Çolak et al. precipitated the Chevreul’s salt by using ammonia and sulphur dioxide. Çalban et al. obtained at the optimum conditions by passing SO2 from leach solutions with NH3-(NH4)2SO4. Yeşiryurt and Çalban investigated the optimum precipitation conditions of Chevreul’s salt from synthetic CuSO4 solutions including Na2SO3. Çalban et al. achieved the precipitation of Chevreul’s salt at the optimum conditions by passing SO2 from synthetic CuSO4 solutions. Çalban et al. examined the precipitation conditions of Chevreul’s salt using (NH4)2SO3 from synthetic aqueous CuSO4 solutions. In light of these studies, it can be said that Chevreul’s salt can be produced practically from both a leach solutions including copper and synthetic CuSO4 solutions.

Keywords: Chevreul’s salt, ammonia, copper sulpfite, sodium sülfite, optimum conditions

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Authors: Javier Paul Montalvo Andia, Adriana Larrea Valdivia, Adolfo Pillihuaman Zambrano

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The most common lixiviant in the leaching process of copper minerals is H₂SO₄, however, the current situation requires more environmentally friendly reagents and in certain situations that have a lower consumption due to the presence of undesirable gangue as muscovite or kaolinite that can make the process unfeasible. The present work studied the leaching of an oxidized copper mineral in an aqueous solution of ammonium nitrate, in order to obtain the optimum leaching conditions of the copper contained in the malachite mineral from Peru. The copper ore studied comes from a deposit in southern Peru and was characterized by X-ray diffractometer, inductively coupled-plasma emission spectrometer (ICP-OES) and atomic absorption spectrophotometry (AAS). The experiments were developed in batch reactor of 600 mL where the parameters as; temperature, pH, ammonium nitrate concentration, particle size and stirring speed were controlled according to experimental planning. The sample solution was analyzed for copper by atomic absorption spectrophotometry (AAS). A simulation in the HSC Chemistry 6.0 program showed that the predominance of the copper compounds of a Cu-H₂O aqueous system is altered by the presence in the system of ammonium complexes, the compound being thermodynamically more stable Cu(NH3)₄²⁺, which predominates in pH ranges from 8.5 to 10 at a temperature of 25 °C. The optimum conditions for copper leaching of the malachite mineral were a stirring speed of 600 rpm, an ammonium nitrate concentration of 4M, a particle diameter of 53 um and temperature of 62 °C. These results showed that the leaching of copper increases with increasing concentration of the ammonium solution, increasing the stirring rate, increasing the temperature and decreasing the particle diameter. Finally, the recovery of copper in optimum conditions was above 80%.

Keywords: ammonium nitrate, malachite, copper oxide, leaching

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Authors: S. Nigri, R. Oumeddour, F. Djazi

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The inhibition of the corrosion of copper in 1 M HNO3 solution by oleic acid was investigated by weight loss measurement, potentiodynamic polarization and scanning electron microscope (SEM) studies. The experimental results have showed that this compound revealed a good corrosion inhibition and the inhibition efficiency is increased with the inhibitor concentration to reach 98%. The results obtained revealed that the adsorption of the inhibitor molecule onto metal surface is found to obey Langmuir adsorption isotherm. The temperature effect on the corrosion behavior of copper in 1 M HNO3 without and with inhibitor at different concentration was studied in the temperature range from 303 to 333 K and the kinetic parameters activation such as Ea, ∆Ha and ∆Sa were evaluated. Tafel plot analysis revealed that oleic acid acts as a mixed type inhibitor. SEM analysis substantiated the formation of protective layer over the copper surface.

Keywords: oleic acid, weight loss, electrochemical measurement, SEM analysis

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Authors: Abbasali Abouei Mehrizi, Hao Wang, Leping Zhou

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Modification of surface wettability is one of the conventional approaches to manipulate the boiling heat transfer. Instead of direct surface modification, in the present study, the surface is decorated with free copper particles with different hydrophobicity. We used millimeter-sized copper particles with two different hydrophobicity. The surface is covered with untreated, hydrophilic, and a combination of hydrophobic and hydrophilic copper particles separately, and the heat flux and wall superheat temperature was measured experimentally and compared with the bare polished copper surface. The results show that the untreated copper particles can slightly improve the boiling heat transfer when the hydrophilic copper particles have better performance. Combining hydrophilic and hydrophobic copper particles reduces boiling heat transfer.

Keywords: boiling heat transfer, copper balls, hydrophobic, hydrophilic

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Authors: Ian Marc G. Cabugsa, Zarine M. Hermita

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Phytoextraction capability of T. catappa in contaminated soils was done in the improvised greenhouse. The plant samples were planted to the soil which contained different concentrations of copper. Chelating agent EDTA was added to observe the uptake and translocation of copper in the plant samples. Results showed a significant increase of copper accumulation with the addition of EDTA at 250 and 1250 mgˑkg-1 concentration of copper in the contaminated soils (p<0.05). While translocation of copper was observed in all treatments, translocation of copper is not significantly enhanced by the addition of EDTA (p>0.05). Uptake and translocation were not directly affected the presence of EDTA. Furthermore, this study suggests that the T. catappa is not a hyperaccumulator of copper, and there is no relationship observed between the length of the plant and the copper uptake in all treatments.

Keywords: chelating agent EDTA, hyperaccumulator, phytoextraction, phytoremediation, terminalia catappa

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Authors: Arindam Pramanik, Parimal Karmakar

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We have explored the synergistic anti-cancer activity of copper ion and acetylacetone complex containing 1,3 diketone group (like curcumin) in metallorganic compound “Copper acetylacetonate” (CuAA). The cytotoxicity mechanism of CuAA complex was evaluated on various cancer cell lines in vitro. Among these, reactive oxygen species (ROS), glutathione level (GSH) in the cell was found to increase. Further mitochondrial membrane damage was observed. The fate of cell death was found to be induced by apoptosis. For application purpose, we have developed a novel biodegradable, non-toxic polymer-based nanoparticle which has hydrophobically modified core for loading of the CuAA. Folic acid is conjugated on the surface of the polymer (chitosan) nanoparticle for targeting to cancer cells for minimizing toxicity to normal cells in-vivo. Thus, this novel drug CuAA has an efficient anticancer activity which has been targeted specifically to cancer cells through polymer nanoparticle.

Keywords: anticancer, apoptosis, copper nanoparticle, targeted drug delivery

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Authors: Hsueh-Cheng Yang

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The generation and design of compound involute spur gearings can be used in gear pump. A compound rack cutter with asymmetric involute teeth is presented for determining the mathematical model of compound gear pumps. This paper covers the following topics: (a) generation and geometry of compound rack cutter is presented and used to generate a compound gear and a compound pinion. (b) Based on the developed compound gears, stress analysis was performed for the symmetric gears and the asymmetric gears. Comparing the results of the stress analysis for the asymmetric involute teeth is superior to the symmetric involute teeth. A numerical example that illustrates the developed compound rack cutter is represented.

Keywords: compound, involute teeth, gear pump, rack cutter

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Authors: Cheng-Yen Huang, Yu-Jen Shih, Ming-Chun Yen, Yao-Hui Huang

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This research developed a fluidized-bed homogeneous crystallization (FBHC) process to remove copper from synthetic wastewater in terms of recovery of highly pure malachite (Cu2(OH)2CO3) pellets. The experimental parameters of FBHC which included pH, molar ratio of copper to carbonate, copper loading, upper flowrate and bed height were tested in the absence of seed particles. Under optimized conditions, both the total copper removal (TR) and crystallization ratio (CR) reached 99%. The malachite crystals were characterized by XRD and SEM. FBHC was capable of treating concentrated copper (1600 ppm) wastewater and minimizing the sludge production.

Keywords: copper, carbonate, fluidized-bed, crystallization, malachite

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Authors: May Thant Zin, Josephine Borja, Hirofumi Hinode, Winarto Kurniawan

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Nanotechnology has multiple and enormous advantages for all application. Therefore, this research is carried out to synthesize and characterize bimetallic iron with copper nano-particles. After synthesizing nano zero valent iron by reduction of ferric chloride by sodium borohydride under nitrogen purging environment, bimetallic iron with copper nanoparticles are synthesized by varying different loads of copper chloride. Due to different standard potential (E0) values of copper and iron, copper is coupled with iron at (Cu to Fe ratio of 1:5, 1:6.7, 1:10, 1:20). It is found that the resulted bimetallic Fe/Cu nanoparticles are composing phases of iron and copper. According to the diffraction patterns indicating the state of chemical combination of the bimetallic nanoparticles, the particles are well-combined and crystalline sizes are less than 1000 Ao (or 100 nm). Specifically, particle sizes of synthesized bimetallic Fe/Cu nanoparticles are ranging from 44.583 nm to 85.149 nm.

Keywords:

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Authors: E. Moroydor Derun, N. Tugrul, F. T. Senberber, A. S. Kipcak, S. Piskin

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In this research, copper borates are synthesized by the reaction of copper sulfate pentahydrate (CuSO4.5H2O) and tincalconite (Na2O4B7.10H2O). The experimental parameters are selected as 80°C reaction temperature and 60 of reaction time. The effect of mole ratio of CuSO4.5H2O to Na2O4B7.5H2O is studied. For the identification analyses X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques are used. At the end of the experiments, synthesized copper borate is matched with the powder diffraction file of “00-001-0472” [Cu(BO2)2] and characteristic vibrations between B and O atoms are seen. The proper crystals are obtained at the mole ratio of 3:1. This study showed that simplified synthesis process is suitable for the production of copper borate minerals.

Keywords: hydrothermal synthesis, copper borates, copper sulfate, tincalconite

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Authors: Robert Prucek, Aleš Panáček, Jan Filip, Libor Kvítek, Radek Zbořil

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The preparation of Cu nanoparticles (NPs) through the reduction of copper ions by sodium borohydride in the presence of sodium polyacrylate with a molecular weight of 1200 is reported. Cu NPs were synthesized at a concentration of copper salt equal to 2.5, 5, and 10 mM, and at a molar ratio of copper ions and monomeric unit of polyacrylate equal to 1:2. The as-prepared Cu NPs have diameters of about 2.5–3 nm for copper concentrations of 2.5 and 5 mM, and 6 nm for copper concentration of 10 mM. Depending on the copper salt concentration and concentration of additionally added polyacrylate to Cu particle dispersion, primarily formed NPs grow through the process of aggregation and/or coalescence into clusters and/or particles with a diameter between 20–100 nm. The amount of additionally added sodium polyacrylate influences the stability of Cu particles against air oxidation. The catalytic efficiency of the prepared Cu particles for the reduction of 4-nitrophenol is discussed.

Keywords: copper, nanoparticles, sodium polyacrylate, catalyst, 4-nitrophenol

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Authors: S. Vasailor, C. Rattanakawin

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Electro-winning of copper metal from dilute sulfate solution (13.7 g/L) was performed in a lab electrolytic cell with stainless-steel cathode and lead-alloy anode. The effects of various parameters including cell voltage, electro-winning temperature and time were studied in order to acquire an appropriate current efficiency of copper deposition. The highest efficiency is about 95% obtaining from electro-winning condition of 3V, 55°C and 3,600 s correspondingly. The cathode copper with 95.5% Cu analyzed using atomic absorption spectrometry can be obtained from this single-winning condition. In order to increase the copper grade, solvent extraction should be used to increase the sulfate concentration, say 50 g/L, prior to winning the cathode copper effectively.

Keywords: copper metal, current efficiency, dilute sulfate solution, electro-winning

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Authors: John Kabuba, Hilary Rutto

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Ion exchange is one of the methods used to remove heavy metal such as copper and cobalt from wastewaters. Parameters affecting the ion-exchange of copper and cobalt aqueous solutions using clinoptilolite are the objectives of this study. Synthetic solutions were prepared with the concentration of 0.02M, 0.06M and 0.1M. The cobalt solution was maintained to 0.02M while varying the copper solution to the above stated concentrations. The clinoptilolite was activated with HCl and H2SO4 for removal efficiency. The pHs of the solutions were found to be acidic hence enhancing the copper and cobalt removal. The natural clinoptilolite performance was also found to be lower compared to the HCl and H2SO4 activated one for the copper removal ranging from 68% to 78% of Cu2+ uptake with the natural clinoptilolite to 66% to 51% with HCl and H2SO4 respectively. It was found that the activated clinoptilolite removed more copper and cobalt than the natural one and found that the electronegativity of the metal plays a role in the metal removal and the clinoptilolite selectivity.

Keywords: clinoptilolite, cobalt and copper, ion-exchange, mass dosage, pH

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Authors: Kai Huang, Assamen Ayalew Ejigu, Mu-Jie Lin, Liang-Chiun Chao

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Nickel oxide and copper-nickel oxide thin films have been successfully deposited by reactive ion beam sputter deposition. Experimental results show that nickel oxide deposited at 300°C is single phase NiO while best crystalline quality is achieved with an O_pf of 0.5. XRD analysis of nickel-copper oxide deposited at 300°C shows a Ni2O3 like crystalline structure at low O_pf while changes to NiO like crystalline structure at high O_pf. EDS analysis shows that nickel-copper oxide deposited at low O_pf is CuxNi2-xO3 with x = 1, while nickel-copper oxide deposited at high O_pf is CuxNi1-xO with x = 0.5, which is supported by Raman analysis. The bandgap of NiO is ~ 3.5 eV regardless of O_pf while the band gap of nickel-copper oxide decreases from 3.2 to 2.3 eV as Opf reaches 1.0.

Keywords: copper, ion beam, NiO, oxide, resistivity, transparent

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Authors: V. K. Arora, V. G. Havanagi, A. K. Sinha

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Copper slag and Jarofix are waste materials, generated during the manufacture of copper and zinc respectively, which have potential for utility in embankment and road construction. Accordingly, a research project was carried out to study the characteristics of copper slag and Jarofix to utilize in the construction of road. In this study, copper slag and Jarofix were collected from Tuticorin, State of Tamil Nadu and Hindustan Zinc Ltd., Chittorgarh, Rajasthan state, India respectively. These materials were investigated for their physical, chemical, and geotechnical characteristics. The materials were collected from the disposal area and laboratory investigations were carried out to study its feasibility for use in the construction of embankment and sub grade layers of road pavement. This paper presents the results of physical, chemical and geotechnical characteristics of copper slag and Jarofix. It was concluded that copper slag and Jarofix may be utilized in the construction of road.

Keywords: copper slag, Jarofix waste, material, road construction

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Authors: Marcela dos P. G. Baltazar, Louise H. Gracioso, Luciana J. Gimenes, Bruno Karolski, Ingrid Avanzi, Elen A. Perpetuo

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In this work, bacterial strains were isolated from environmental samples from a copper mine and three of them presented potential for bioremediation of copper. All the strains were identified by mass spectrometry (MALDI-TOF-Biotyper) and grown in three diferent media supplemented with 100 ppm of copper chloride in flasks of 500mL and it was incubated at 28 °C and 180 rpm. Periodically, samples were taken and monitored for cellular growth and copper biosorption by spectrophotometer UV-Vis (600 nm) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), respectively. At the end of exponential phase of cellular growth, the biomass was utilized to construct a correlation curve between absorbance and dry mass of the cells. Among the three isolates with potential for biorremediation, 1 strain exhibit capacity the most for bioremediation of effluents contaminated by copper being identified as Rhodococcus erythropolis.

Keywords: bioprocess, bioremediation, biosorption, copper

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Authors: Hilary Rutto

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Leaching with acids are the most commonly reagents used to remove copper ions from its copper ores. It is important that the process conditions are optimized to improve the leaching efficiency. In the present study the effects of pH, oxidizing agent (hydrogen peroxide), stirring speed, solid to liquid ratio and acid concentration on the leaching of copper ions from it ore were investigated using a pH Stat apparatus. Copper ions were analyzed at the end of each experiment using Atomic Absorption (AAS) machine. Results showed that leaching efficiency improved with an increase in acid concentration, stirring speed, oxidizing agent, pH and decreased with an increase in the solid to liquid ratio.

Keywords: leaching, copper, oxidizing agent, pH stat apparatus

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Authors: Yameen Ahmed, Jamshid Hussain, Farman Ullah, Sohaib Asif

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The investigation aims at the synthesis of copper oxide and cobalt oxide nanoparticles using Spinacia oleracea leaf extract. These nanoparticles have many properties and applications. They possess antimicrobial catalytic properties and also they can be used in energy storage materials, gas sensors, etc. The Spinacia oleracea leaf extract behaves as a reducing agent in nanoparticle synthesis. The plant extract was first prepared and then treated with copper and cobalt salt solutions to get the precipitate. The salt solutions used for this purpose are copper sulfate pentahydrate (CuSO₄.5H₂O) and cobalt chloride hexahydrate (CoCl₂.6H₂O). The UV-Vis, XRD, EDX, and SEM techniques are used to find the optical, structural, and morphological properties of copper oxide and cobalt oxide nanoparticles. The UV absorption peaks are at 326 nm and 506 nm for copper oxide and cobalt oxide nanoparticles.

Keywords: cobalt oxide, copper oxide, green synthesis, nanoparticles

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Authors: George Eduful, Kingsford J. A. Atanga

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Copper clad steel wire (CCS) is primarily used for grounding applications to reduce the high incidence of copper ground conductor theft in electrical installations. The cross sectional area of the CCS is selected by relating the diameter equivalence to a copper conductor. The main difficulty is how to use a simple analytical relation to determine the right conductivity of CCS for a particular application. The use of Eddy-Current instrument for measuring conductivity is known but in most cases, the instrument is not readily available. The paper presents a simplified approach on how to size and determine CCS conductivity for a given application.

Keywords: copper clad steel wire, conductivity, grounding, skin effect

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Authors: Maxim Panov, Evgenia Khairullina, Sergey Ermakov, Oleg Gundobin, Vladimir Kochemirovsky

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The continuous in situ laser-induced catalysis proceeding via generation and growth of nano-sized copper particles was discussed. Also, the simple and lost-cost method for manufacturing of microstructural copper electrodes was proposed. The electrochemical properties of these electrodes were studied by cyclic voltammetry and impedance spectroscopy. The surface of the deposited copper structures (electrodes) was investigated by X-ray photoelectron spectroscopy and atomic force microscopy. These microstructures are highly conductive and porous with a dispersion of pore size ranging from 50 nm to 50 μm. An analytical response of the fabricated copper electrode is 30 times higher than those observed for a pure bulk copper with similar geometric parameters. A study of sensory characteristics for hydrogen peroxide determination showed that the value of Faraday current at the fabricated copper electrode is 2-2.5 orders of magnitude higher than for etalon one.

Keywords: laser-induced deposition, electrochemical electrodes, non-enzymatic sensors, copper

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Authors: Sercan Basit, Muhlis N. Sarıdede

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Metal amounts of copper based compounds in the various wastes have been recovered successfully by hydrometallurgical treatment methods in the literature. X-ray diffraction pattern of the brass melting slag demonstrates that it contains sufficient amount of recoverable copper. Recovery of copper from brass melting dross by sulfuric acid leaching and the effect of temperature and acid and oxidant concentration on recovery rate of copper have been investigated in this study. Experiments were performed in a temperature-controlled reactor in sulfuric acid solution in different molarities using solid liquid ratio of 100 g/L, with leaching time of 300 min. Temperature was changed between 25 °C and 80 °C and molarity was between 0.5 and 3M. The results obtained showed that temperature has important positive effect on recovery whereas it decreases with time. Also copper was recovered in larger amounts from brass dross in the presence of H2O2 as an oxidant according to the case that oxidant was not used.

Keywords: brass dross, copper recovery, hydrogen peroxide, leaching

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Authors: V. K. Stalin, M. Kirithika, K. Shanmugam, K. Tharini

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Nanotechnology has been widely used in many applications such as medical, electronics, robotics and also in geotechnical engineering area through stabilization of bore holes, grouting etc. In this paper, an attempt is made for understanding the influence of nano copper slag (1%, 2% & 3%) on the index, compaction and UCC strength properties of natural soil (CH type) with and without lime stabilization for immediate and 7 days curing period. Results indicated that upto 1% of Nano copper slag, there is an increment in UC strength of virgin soil and lime stabilised soil. Beyond 1% nano copper slag, there is a steep reduction in UC strength and increase of plasticity both in lime stabilised soil and virgin soil. The effect of lime is found to show more influence on large surface area of nano copper slag in natural soil. For both immediate and curing effect, with 1% of Nano copper slag, the maximum unconfined compressive strength was 38% and 106% higher than that of the virgin soil strength.

Keywords: lime, nano copper slag, SEM, XRD, stabilisation

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Authors: Arunkumar Thirugnanasambantham, Velraj Ramalingam

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An experimental attempt has been made to study the effect of system integration by two different concentrator assisted desalting systems. The compound parabolic concentrator (CPC) and compound conical concentrator (CCC) are used in this research work. Two solar desalination systems, the single slope solar still (SSSS) and pyramid solar still (PSS), have been integrated with a CCC and compound parabolic concentrator-concentric circular tubular solar still (CPC-CCTSS). To study the effect of system integration, a thick cloth prevents the entry of sunlight into the solar still top. Additionally, the concentrator assisted desalting systems are equipped with phase change material (PCM) for enhancement. In CCC-SSSS, PCM has been filled inside copper balls and placed on the SSSS basin. The PCM is loaded in the specially designed circular trough of the tubular solar still. Here, the used concentrators and distillers are not the same. Two methodologies are followed here to produce the fresh water even while the distillers are blocked from the sunlight. They are (1) thermosyphon effect in CCC-SSSS and (2) waste heat recovery from CPC-CCTSS. The results showed that the productivity of CCC-SSSS, CCC-SSSS with PCM and CCC-SSSS (PCM) top cover shaded were found as 2680 ml / m² / day, 3240 ml / m² / day, and 1646 ml / m² / day. Similarly, the productivity of the CPC-CCTSS-PSS, CPC-CCTSS (PCM)-PSS and CPC-CCTSS (PCM)-PSS top cover shaded were found as 7160 ml / m² / day, 7346 ml / m² / day, and ml / m² / day. The productivity of the CCC-SSSS and CPC-CCTSS-PSS is examined, and conclusions are drawn such as the solar radiation blocked distillers productivity did not drop to zero.

Keywords: compound conical concentrator, compound parabolic concentrator, desalination, system integration

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Authors: Abdel Rahman Altakhaineh, Mohamma Alaghawat, Hiba Alhendi

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This paper reports an investigation of the comprehension of English compound nouns by sixty Arabic-speaking English Foreign Language (EFL) learners majoring in English at the University of Jordan, Amman. The investigation focused on the problems that these learners may encounter in understanding certain types of compounds and their ability to use their L1 compound noun knowledge to produce the meaning of L2 compound nouns. Participants whose English proficiency level was advanced underwent a test to identify the meaning ofan underlined compound without using a dictionary. Theresponses to the three different types of compounds were analyzed usingTwo-Way repeated measures ANOVA, and the results showed that there were different endocentric and exocentric compound responses within subordinative compounds, with a statistically significant difference between the two in favor of endocentric compounds. We argue that the endocentric, especially subordinative endocentric compounds,weremore easily understood due to its representative nature, i.e., because the head represents the meaning of the whole compound. The study concludes with pedagogical implications for teaching compound nouns.

Keywords: morphology, compounding, SLA, arabic-speaking EFL learners

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Authors: Travis J. Meyer, Jasodra Ramlall, Phyo Thu, Nidhi Gadura

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For centuries humans have used the antimicrobial properties of copper to their advantage. Yet, after all these years the underlying mechanisms of copper mediated cell death in various microbes remain unclear. We had explored the hypothesis that copper mediated increased levels of lipid peroxidation in the membrane fatty acids is responsible for increased killing inEscherichia coli. In this study we show that in both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa) bacteria there is a strong correlation between copper mediated cell death and increased levels of lipid peroxidation. Interestingly, the non-spore forming gram positive bacteria as well as gram negative bacteria show similar patterns of cell death, increased levels of lipid peroxidation, as well as genomic DNA degradation, however there is some difference inloss in membrane integrity upon exposure to copper alloy surface.

Keywords: antimicrobial, copper, gram positive, gram negative

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Authors: Yufan Mu

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High salinity process water (HSPW) is often applied in copper ore flotation to alleviate freshwater shortage; however, it is detrimental to copper flotation as it strongly enhances copper activation of pyrite. In this study, the depression effect of a strong oxidiser, potassium ferrate (𝐾₂𝐹₄), on the flotation of copper-activated pyrite was tested to realise the selective separation of pyrite from copper minerals (e.g., chalcopyrite) in flotation using HSPW. The flotation results show that when (𝐾₂𝐹₄) was added in the flotation cell during conditioning, (𝐾₂𝐹₄) could selectively depress copper-activated pyrite while improving chalcopyrite flotation. The depression mechanism of (𝐾₂𝐹₄) on pyrite was ascribed to the significant increase in the pulp potential (Eₕ), dissolved oxygen (DO) concentration and the amount of ferric oxyhydroxides as a result of ferrate decomposition. In the flotation cell, the high Eh and DO concentration promoted the oxidation of low valency metal species (𝐶⁺𝐹e²⁺) released from mineral surfaces and forged steel grinding media, and the resultant high valency metal oxyhydroxides 𝐶u(𝑂H)₂⁄Fe(OH)₃ together with the ferric oxyhydroxides from ferrate decomposition preferentially precipitated on pyrite surface due to its more cathodic nature compared with chalcopyrite, which increased pyrite surface hydrophilicity and reduced its floatability. This study reveals that (𝐾₂𝐹₄) is a highly efficient depressant for pyrite when separating copper minerals from pyrite in flotation using HSPW if dosed properly.

Keywords: copper flotation, pyrite depression, copper-activated pyrite, potassium ferrate, high salinity process water

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