Study of the Effect of Nitrate and Sulfate Solutions on the Properties of Copper Nanopowder Synthesized by Electrochemical Method

The electrochemical method is efficient, cost effective, and environmentally friendly process. Copper nanopowder has been known, as a nontoxic, inexpensive, highly conductive, excellent microbial agent, catalytic, and sensors applicable. Copper nanopowder was prepared by an electrochemical method under various conditions. The effect of type and concentration of electrolyte solution, and the sample treated with thiourea and ascorbic acid on the size and purity of copper nanopowder was investigated. Two different salts copper: sulfate and nitrate aqueous solutions (CuSO4.5H2O), Cu(NO3)2.5H2O were used to produce copper nanopowder. The synthesized copper nanopowder was identified using X-ray diffraction (XRD), the scanning electron microscope (SEM), and Energy Dispersive Spectrum (EDS). The results of XRD patterns revealed a high degree of crystallinity, monophasic nature, and pure copper powder with no impurities or oxides observed for both electrolyte solutions after treated with 2 percent of ascorbic acid. It was confirmed that particle size at room temperature was as small as 25nm when the copper nitrate is used as an electrolyte solution compared to copper sulfate (41nm).

Assessing the Grindability Behaviour of Anka (Zamfara State, Nigeria) Manganese Ore towards Effective Manganese Mineral Liberation

The Bond standard grindability test provides a Work Index that is widely used to estimate the energy required for ore grinding. The research investigates the work index of Anka Manganese ore at Anka deposit in Zamfara state, Nigeria. The reference ore (Quartz) was sourced from the studied ore overburden in the mine. The test ore and the reference ore were characterized using Energy Dispersive X-ray fluorescence spectrometer, X - ray Diffractometer and the Scanning Electron Microscope equipped with Energy Dispersive Spectrum. 500 g each of the manganese ore and quartz were sampled and prepared by crushing and grinding to 100% passing 1200 μm sieve. 100 g of prepared ores were charged into array of sieve arranged in √2 series from 1000 μm to 63 μm. Set of sieves were mounted on the Automated Pascal Denver sieve shaker (16153) and was in operation for 20 minutes. The work index of reference ore was used to calculate the work index of the test ore using Gaudin Schuman expression to obtain a work index of 14.16 Kwh/ton for test ore and it lies within the work index of 10-15.14 Kwh/ton for manganese ore stated in the literature and the energy expended to achieve communition at mineral liberation size was calculated to be 3.3984 Kw/ton.

SYNTHESIS AND CHARACTERIZATION: COMPOSITE OF GRAPHENE OXIDE BASED PALM KERNEL SHELL WASTE WITH FE3O4

SYNTHESIS AND CHARACTERIZATION: COMPOSITE OF GRAPHENE OXIDE BASED PALM KERNEL SHELL WASTE WITH Fe3O4. In this study, GO-Fe3O4 were fabricated by co-precipitation technique and the graphene oxide (GO) were synthesized from an agricultural biomass, palm kernel shell, via Hummer’s method. Field Emission Scanning Electron Microscopy and Energy Dispersive Spectrum (FESEM-EDS), Fourier Transform Infra-Red (FT-IR) spectroscopy, X-Ray Diffractometer (XRD), and Raman spectroscopy were used to analysis the successful attachment of Fe3O4 onto the surface of GO. Morphology observation showed that Fe3O4 were heterogeneously deposited on the surface of GO. FT-IR spectra shows peak that incorporated to oxygenated functional groups and sharp peak at 586 cm-1 confirmed to lattice absorption of Fe3O4. The percentage of composition of GO-Fe3O4 was characterized by energy dispersive spectroscopy and the results also confirmed in XRD exhibits similar properties with JCPDS 19-0629 for magnetite more dominant than GO. From Raman spectroscopy analysis shows that 1343.82 cm-1 (D-band) and 1584.62 cm-1 (G-band) and 2698 cm-1 (2D-band) indicates GO and GO-Fe3O4 were successfully synthesized.

Temperature-Induced Plasmon Excitations for the α–T3 Lattice in Perpendicular Magnetic Field

We have investigated the α–T3 model in the presence of a mass term which opens a gap in the energy dispersive spectrum, as well as under a uniform perpendicular quantizing magnetic field. The gap opening mass term plays the role of Zeeman splitting at low magnetic fields for this pseudospin-1 system, and, as a consequence, we are able to compare physical properties of the the α–T3 model at low and high magnetic fields. Specifically, we explore the magnetoplasmon dispersion relation in these two extreme limits. Central to the calculation of these collective modes is the dielectric function which is determined by the polarizability of the system. This latter function is generated by transition energies between subband states, as well as the overlap of their wave functions.

Self-healing bacterial cementitious concrete composites: development and performance evaluation

The principal objective of the research is to contribute towards attaining the goal of developing self-healing cementitious concrete composites by incorporating bacteria as healing agent. Since the root cause of the majority of structural failure is attributed to concrete cracking, there is a compelling economic incentive to develop a concrete that can treat and repair the damage all by itself. Even though some research has been carried out in this area, a major breakthrough in identifying the types of bacteria, modes to protect this bacteria from high pH concrete environment and nutrients for effective healing are yet to materialise. For the present study, three different bacteria namely, Sporosarcina ureae, Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii and two protective vehicles such as zeolite and pumice were selected to determine the best combination among them for self-healing. Normal and fibre reinforced mortar and engineered cementitious composite (ECC) specimens were employed for the study. In order to develop self-healing bacterial concrete based materials, it is crucial to understand whether the introduction of mineral producing bacteria and nutrients adversely affect the properties. Thus, various concentrations of bacteria and nutrients were tested to determine the best possible combinations without sacrificing concrete properies. Evaluation of healing effect was determined by comparing compressive strength, sorptivity and rapid chloride permeability (RCPT), four point bending and ultrasonic pulse velocity (UPV) properties of sound and damaged specimens at different ages. Healing associated with crack closure was visualised and analysed using scanning electronmicroscopy (SEM), Energy Dispersive Spectrum Energy (EDS) and X-ray diffraction (XRD) studies. Finally, an attempt was made to employ statistical models for parameter optimization of self-healing characteristics in terms of compressive strength, sorptivity, RCPT and UPV by design and analysis of experiments. Evaluation of results to determine self-healing efficiency indicated that a significant amount of self-healing was achieved by all three selected bacteria, out of which Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii found to be promising choices. Both zeolite and pumice turned out to be effective protective vehicles. Statistical modelling of the experiment proved to be the ideal choice for modelling self-healing characteristics.

Self-healing bacterial cementitious concrete composites: development and performance evaluation

The principal objective of the research is to contribute towards attaining the goal of developing self-healing cementitious concrete composites by incorporating bacteria as healing agent. Since the root cause of the majority of structural failure is attributed to concrete cracking, there is a compelling economic incentive to develop a concrete that can treat and repair the damage all by itself. Even though some research has been carried out in this area, a major breakthrough in identifying the types of bacteria, modes to protect this bacteria from high pH concrete environment and nutrients for effective healing are yet to materialise. For the present study, three different bacteria namely, Sporosarcina ureae, Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii and two protective vehicles such as zeolite and pumice were selected to determine the best combination among them for self-healing. Normal and fibre reinforced mortar and engineered cementitious composite (ECC) specimens were employed for the study. In order to develop self-healing bacterial concrete based materials, it is crucial to understand whether the introduction of mineral producing bacteria and nutrients adversely affect the properties. Thus, various concentrations of bacteria and nutrients were tested to determine the best possible combinations without sacrificing concrete properies. Evaluation of healing effect was determined by comparing compressive strength, sorptivity and rapid chloride permeability (RCPT), four point bending and ultrasonic pulse velocity (UPV) properties of sound and damaged specimens at different ages. Healing associated with crack closure was visualised and analysed using scanning electronmicroscopy (SEM), Energy Dispersive Spectrum Energy (EDS) and X-ray diffraction (XRD) studies. Finally, an attempt was made to employ statistical models for parameter optimization of self-healing characteristics in terms of compressive strength, sorptivity, RCPT and UPV by design and analysis of experiments. Evaluation of results to determine self-healing efficiency indicated that a significant amount of self-healing was achieved by all three selected bacteria, out of which Sporosarcina pasteurii and Bacillus subtilis subsp. spizizenii found to be promising choices. Both zeolite and pumice turned out to be effective protective vehicles. Statistical modelling of the experiment proved to be the ideal choice for modelling self-healing characteristics.

GAS SENSING PROPERTIES OF NANOJUNCTION OF NETWORKED ZnO NANOWIRES UNDER THE CORRELATION BETWEEN OPERATING TEMPERATURE AND UV RADIATION

The networked ZnO nanowires (NWs) are synthesized by thermal evaporation at 900 oC, using a mixture of ZnO and graphite. The morphology, crystalline structure, and chemical composition of the NWs are evaluated by field-emission scanning electron microscopy, X-ray diffraction, and energy-dispersive spectrum. The NO2 gas-sensing properties of a networked ZnO NWs-based sensor are considered in a correlation between the operating temperature and UV radiation with various operating temperatures as well as UV intensities. The results reveal that the sensing properties of the UV-illuminated sensor measured at room temperature are comparable to those of the heated sensor. The results also indicate that the UV intensity affects strongly both the response and the sensing kinetic of the sensor at all operating temperatures. Furthermore, based on a systematic investigation of the sensing performance of the sensor under both UV illumination and thermal activation, a model to explain the role of UV illumination is also proposed.

The Effect of Macro-Particle Blocking Plate on the Morphology of Coated CrN Film by Arc Cathodic Evaporation Method

Macro-particles often have a negatively affect on the properties of the coatings fabricated by arc cathodic evaporation. To prevent these macro-particles forming on the coating, a blocking plate can be used to filter out them. Disc-shaped blocking plates with different diameters of Df influence the number of macro-particles and the deposition rate of the coating film. The structure and morphology of macro-particles and coatings were investigated by optical microscope, stereoscopic optical microscope, electron microscope, energy dispersive spectrum (EDS), and XRD spectrum. The results show that the use of a larger diameter of the blocking plate reduces the density of macro-particles but also reduces the thickness of the coating as well as deposition rate of CrN film.

Investigation on the Influences of Curing Time on the Cracking Resistance of Semiflexible Pavement Mixture

Semiflexible pavement (SFP) is constructed by pouring grouting material into porous asphalt (PA) mixture. SFP has been widely used to address the rutting distress issues across China in recent years. However, studies on its cracking resistance are limited and the failure mechanism of the SFP mixture has not been fully explored nor understood in a comprehensive way. Moreover, the influences of the curing time on the cracking property of the SFP mixture are still not clear. To this end, the strength development and shrinkage properties of grouting materials are determined by utilizing the three-point beam bending test and the shrinkage test. The semicircular bending (SCB) test and the scanning electron microscope-energy-dispersive spectrum (SEM-EDS) are conducted in this study to investigate the cracking resistance and failure mechanism of SFP mixtures with different curing days. Results show that both the strength and shrinkage of grouting materials would develop as the curing time was extended from 0 days to 14 days. SCB test results show that SFP mixtures have higher tensile strength but a lower flexibility index (FI) than PA mixture. It is found that the cracking resistance of SFP mixture is influenced by both the grouting materials’ strength and shrinkage. SEM-EDS analysis demonstrates that the cement-asphalt interface is a stress concentration site and therefore is the weak zone where cracks would initially develop. The microcracks found in the interface zone with different curing days may contribute to the decline of the SFP mixture’s anticracking ability. This study sheds light on the further application of SFP in practical projects.

Removal of zinc(II) from livestock and poultry sewage by a zinc(II) resistant bacteria

In order to remediate Zn-contaminated livestock and poultry sewage, a zinc-resistant bacterial strain was screened and isolated from the manure of livestock and poultry and identified by molecular biology. The optimal conditions for removing zinc(II) from strain XZN4 were determined by single-factor experiments as follows: within 3 times of repeated use, pH value was 5, initial concentration of zinc(II) was 100 mg/L, the amount of bacteria was 6 g/L, the temperature was 25–30 °C, and the removal equilibrium time was 60 min. Then, through adsorption isotherm model, scanning electron microscope image, energy dispersive spectrum analysis, infrared spectrum analysis and sterilization control experiment, it was found that the removal of zinc(II) by bacteria was single-molecule layer adsorption, which was carried out in coordination with degradation. The influence of different concentrations of copper(II), ammonia nitrogen, phosphorus, and chlortetracycline on the removal of zinc(II) from livestock and poultry sewage by XZN4 strain in the actual application was discussed. The bacteria can reduce the concentration of zinc(II) from the complex livestock and poultry waste water to below the discharge standard, and has a strong environmental tolerance, the highest removal rate reached 88.6% and the highest removal amount reached 10.30 mg/L. The screening and application of XZN4 strain can thus be of great significance for the microbial treatment of zinc(II) in complex livestock and poultry sewage. The results will provide guidance for the microbial remediation of heavy metal pollution.