Search results for: magnesium sulfate coating

Authors: M. Mahdavi, M. Mohseni, R. Rafiei, H. Yari

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Environmental factors can deteriorate the automotive coatings significantly. Such as UV radiations, humidity, hot-cold shock and destructive chemical compounds. Furthermore, some natural materials such as bird droppings and tree gums have the potential to degrade the coatings as well. The present work aims to study the mechanism of degradation for two automotive refinish coating (PU based) systems exposed to two types of biological materials, i.e. Arabic gum and the simulated bird dropping, pancreatin. To reach this goal, effects of these biological materials on surface properties and appearance were studied using different techniques including digital camera, FT-IR spectroscopy, optical microscopy, and gloss measurements. In addition, the thermo-mechanical behavior of coatings was examined by DMTA. It was found that cross-linking had a crucial role on the biological resistance of clear coat. The higher cross-linking enhanced biological resistance.

Keywords: refinish clear coat, pancreatin, Arabic gum, cross-linking, biological degradation

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Authors: Jean C. A. Sousa, Julio Cesar Maciel Santos, Andressa J. Rubio, Edneia A. S. Paccola, Natália U. Yamaguchi

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A bibliometric analysis in the Web of Science database was used to identify overall scientific results of graphene inks to date (2008 to 2018). The objective of this study was to evaluate the evolutionary tendency of graphene inks research and to identify its aspects, aiming to provide data that can guide future work. The contributions of different researches, languages, thematic categories, periodicals, place of publication, institutes, funding agencies, articles cited and applications were analyzed. The results revealed a growing number of annual publications, of 258 papers found, 107 were included because they met the inclusion criteria. Three main applications were identified: synthesis and characterization, electronics and surfaces. The most relevant research on graphene inks has been summarized in this article, and graphene inks for electronic devices presented the most incident theme according to the research trends during the studied period. It is estimated that this theme will remain in evidence and will contribute to the direction of future research in this area.

Keywords: bibliometric, coating, nanomaterials, scientometrics

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Authors: Preeti Pal, Anjali Pal

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Chitosan is an effective sorbent for removal of contaminants from wastewater. However, the ability of pure chitosan is specific because of its cationic charge. It causes repulsion in the removal process of various cationic charged molecules. The present study has been carried out for the successful removal of Pb²⁺ ions from aqueous solution by modified chitosan beads. Surface modification of chitosan (CS) beads was performed by using the anionic surfactant (AS), sodium dodecyl sulfate (SDS). Micelle aggregation property of SDS has been utilized for the formation of bilayer over the CS beads to produce surfactant modified chitosan (SMCS) beads. Prepared adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) in order to find out their composition and surface morphology. SMCS beads, when compared to the pure CS beads, showed three times higher adsorption. This higher adsorption is believed to be due to the adsolubilization of Pb²⁺ ions on SDS bilayer. This bilayer provides more adsorption sites for quick and effective removal of Pb²⁺ ions from the aqueous phase. Moreover, the kinetic and adsorption isotherm models were employed to the obtained data for the description of the lead adsorption processes. It was found that the removal kinetics follows pseudo-second order model. Adsorption isotherm data fits well to the Langmuir model. The maximum adsorption capacity obtained is 100 mg/g at the dosage of 0.675 g/L for 50 mg/L of Pb²⁺. The adsorption capacity is subject to increase with increasing the Pb²⁺ ions concentration in the solution. The results indicated that the prepared hydrogel beads are efficient adsorbent for removal of Pb²⁺ ions from the aqueous medium.

Keywords: adsolubilisation, anionic surfactant, bilayer, chitosan, Pb²⁺

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Authors: Honorio Salmeron Valdivieso, Andy Keane, David Toal

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In the area of mechanical reverse engineering, processes often encounter difficulties capturing small, highly localized surface information. This could be the case if a physical turbine was 3D scanned for lifecycle management or robust design purposes, with interest on eroded areas or scratched coating. The limitation partly is due to insufficient automated frameworks for handling -localized - surface information during the reverse engineering pipeline. We have developed a tool for blending surface patches with arbitrary irregularities into a base body (e.g. a CAD solid). The approach aims to transfer small surface features while preserving their shape and relative placement by using a multi-resolution scheme and rigid deformations. Automating this process enables the inclusion of outsourced surface information in CAD models, including samples prepared in mesh handling software, or raw scan information discarded in the early stages of reverse engineering reconstruction.

Keywords: application lifecycle management, multiresolution deformation, reverse engineering, robust design, surface blending

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Authors: Juan Patricio Ibáñez, Exequiel López

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A method for synthesizing copper nanoparticles through an electrochemical approach is proposed, employing surfactants to stabilize the size of the newly formed nanoparticles. The electrolyte was made up of a matrix of H₂SO₄ (190 g/L) having Cu²⁺ (from 3.2 to 9.5 g/L), sodium dodecyl sulfate -SDS- (from 0.5 to 1.0 g/L) and Tween 80 (from 0 to 7.5 mL/L). Tween 80 was used in a molar relation of 1 to 1 with SDS. A glass cell was used, which was in a thermostatic water bath to keep the system temperature, and the electrodes were cathodic copper as an anode and stainless steel 316-L as a cathode. This process was influenced by the control exerted through the initial copper concentration in the electrolyte and the applied current density. Copper nanoparticles of electrolytic purity, exhibiting a spherical morphology of varying sizes with low dispersion, were successfully produced, contingent upon the chemical composition of the electrolyte and current density. The minimum size achieved was 3.0 nm ± 0.9 nm, with an average standard deviation of 2.2 nm throughout the entire process. The deposited copper mass ranged from 0.394 g to 1.848 g per hour (over an area of 25 cm²), accompanied by an average Faradaic efficiency of 30.8% and an average specific energy consumption of 4.4 kWh/kg. The chemical analysis of the product employed X-ray powder diffraction (XRD), while physical characteristics such as size and morphology were assessed using atomic force microscopy (AFM). It was identified that the initial concentration of copper and the current density are the variables defining the size and dispersion of the nanoparticles, as they serve as reactants in the cathodic half-reaction. The presence of surfactants stabilizes the nanoparticle size as their molecules adsorb onto the nanoparticle surface, forming a thick barrier that prevents mass transfer with the exterior and halts further growth.

Keywords: copper nanopowder, electrochemical synthesis, current density, surfactant stabilizer

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Authors: Hamed Ahari, Sepideh Farokhi, Mohamad Reza Abedini

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This paper focuses on inactivation of the growth of the bacterial mixture, Salmonella enteritidis, Staphylococcus aureus, Bacillus cereus and Escherichia coli, experimentally subjected to the chicken eggshell by two types of nano particle-Ag, composite film and colloidal spray carried out at concentrations of 500, 1000 and 2000 ppm over 28 days. The GLM, Repeated Measurement-ANOVA procedure was used to analyze the effect of time and concentration of nano groups on inactivation of bacteria, simultaneously. The maximum reduction of the bacterial growth was respected to the group “spray 2000 ppm” for which the value of the bacteria reached the minimum (0.93±0.42) on day 7, calculated to be 0.0 on days14 and 28 and followed by the group “spray 1000 ppm”. It was obviously concluded that increasing the dilution of nano coating in spray and film created a significant decrease in the number of bacteria colonies on the eggshells but the effect of packaging in different concentrations of nanocomposite was not statistically significant in different days of the study.

Keywords: nano particle, composite film, eggshell, bacteria

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Authors: Imana Shahrin Tania, Mohammad Ali

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The present study reports the synthesis, characterization and application of nano-sized zinc-oxide (ZnO) particles on a cotton fabric surface. The aim of the investigations is to impart the antimicrobial activity on textile cloth. Nanoparticle is synthesized by wet chemical method from zinc sulphate and sodium hydroxide. SEM (scanning electron micrograph) images are taken to demonstrate the surface morphology of nanoparticles. XRD analysis is done to determine the crystal size of the nanoparticle. With the conformation of nanoformation, the cotton woven fabric is treated with ZnO nanoparticle by mechanical thermo-fixation (pad-dry-cure) technique. To increase the wash durability of nano treated fabric, an acrylic binder is used as a fixing agent. The treated fabric shows up to 90% bacterial reduction for S. aureus (Staphylococcus aureus) and 87% for E. coli (Escherichia coli) which is appreciable for bacteria protective clothing.

Keywords: nanoparticle, zinc oxide, cotton fabric, antibacterial activity, binder

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Authors: Kyriaki Kalaitzidou, Athanasia Tolkou, Christina Raptopoulou, Manassis Mitrakas, Anastasios Zouboulis

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Phosphate rock is the main source of phosphorous (P) in fertilizers and is essential for high crop yield in agriculture; currently, it is considered as a critical element, phasing scarcity. Chemical precipitation, which is a commonly used method of phosphorous removal from wastewaters, finds its significance in that phosphates may be precipitated in appropriate chemical forms that can be reused-recovered. Most often phosphorous is removed from wastewaters in the form of insoluble phosphate salts, by using salts (coagulants) of multivalent metal ions, most frequently iron, aluminum, calcium, or magnesium. The removal degree is affected by various factors, such as pH, chemical agent dose, temperature, etc. In this study, phosphate precipitation from the secondary (biologically treated) effluent of a municipal wastewater treatment plant is examined. Using chlorosulfate (FeClSO4) it was attempted to either remove and/or recover PO43-. Results showed that the use of Fe3+ can achieve residual concentrations lower than the commonly applied legislation limit of PO43- (i.e. 3 mg PO43-/L) by adding 7.5 mg/L Fe3+ in the secondary effluent with an initial concentration of about 10 mg PO43-/L and at pH range between 6 to 9. In addition, the formed sediment has a percentage of almost 24% PO43- content. Therefore, simultaneous removal and recovery of PO43- as ferric phosphate can be achieved, making it possible for the ferric phosphate to be re-used as a possible (secondary) fertilizer source.

Keywords: ferric phosphate, phosphorus recovery, phosphorus removal, wastewater treatment

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Authors: Soroor Ghaziof, Wei Gao

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Zn alloy and composite coatings are widely used in buildings and structures, automobile and fasteners industries to protect steel component from corrosion. In this paper, Zn-Ni-Al2O3 nano-composite coatings were electrodeposited on mild steel using a novel sol enhanced electroplating method. In this method, transparent Al2O3 sol was added into the acidic Zn-Ni bath to produced Zn-Ni-Al2O3 nano-composite coatings. The effect of alumina sol on the electrodeposition process, and coating properties was investigated using cyclic voltammetry, XRD, ESEM and Tafel test. Results from XRD tests showed that the structure of all coatings was single γ-Ni5Zn21 phase. Cyclic voltammetry results showed that the electrodeposition overpotential was lower in the presence of alumina sol in the bath, and caused the reduction potential of Zn-Ni to shift to more positive values. Zn-Ni-Al2O3 nano composite coatings produced more uniform and compact deposits, with fine grained microstructure when compared to Zn-Ni coatings. The corrosion resistance of Zn-Ni coatings was improved significantly by incorporation of alumina nano particles into the coatings.

Keywords: Zn-Ni-Al2O3 composite coatings, steel, sol-enhanced electroplating, corrosion resistance

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Authors: Gheorghe Giurgiu, Manole Cojocaru, Mihnea Andrei Nicodin

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Background: Inflammation has the main role in the progression of endometriosis. The mechanisms by which endometriosis induces a chronic pain state remain poorly understood. Unfortunately, there is no known cure for endometriosis. But you can manage it with medication and at-home treatments. Some findings have highlighted the main role of inflammation in endometriosis by acting on proliferation, apoptosis, and angiogenesis. The introduction of new agents can be effective in improving the condition of patients; for example, plants are promising sources of bioactive natural components. Objectives: These natural compounds could be interesting strategies in therapy. While there is no absolute cure for this condition, some home remedies can relieve the pain and discomfort it brings. The purpose of this study is to summarize the potential action of Deniplant nutraceuticals in endometriosis by acting on inflammation. Materials and Methods: The primary symptoms of endometriosis are pelvic pain and infertility. The use of Deniplant nutraceuticals could be interesting in disease management for women. Results: Treating pain-related aspects of endometriosis would contribute to the improvement of mental health and daytime function. Because the microbiome can influence inflammation, new therapies can develop through its natural modulation. There are other options, including natural remedies, herbs like cinnamon twigs or licorice root, or supplements such as thiamine, magnesium, or omega-3 fatty acids. Conclusion: Deniplant nutraceuticals can downregulate inflammation in endometriosis. Nevertheless, the limited number of studies focusing on the different interactions of Deniplant nutraceuticals in endometriosis restricts its clear and immediate use in a therapeutic strategy.

Keywords: endometriosis, diet, Deniplant nutraceuticals, pain

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Authors: Tamar Khardziani, Violeta Berikashvili, Amrosi Chkuaseli, Vladimir Elisashvili

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The main objectives of this proposal are to develop low-cost, innovative, and competitive technologies for the production of mycelial biomass of medicinal mushrooms as a natural food supplement for poultry. To fulfill this task, industrial strains of Lentinus edodes, Ganoderma lucidum, and Pleurotus ostreatus were used in this study. The solid-state fermentation (SSF) of wheat grains, wheat bran, and soy flour was performed in flasks and bags. Among nine mushroom strains, P. ostreatus 2191 appeared to be the most productive in protein biomass accumulation in the SSF of wheat bran. All mushrooms produced exopolysaccharide with the highest yield of 5-8 mg/mL depending on fungal strain and growth substrate. Supplementation of medium with 1% glycerol and 2-4% peptone favored mushroom growth and protein accumulation. Among inorganic nitrogen sources, KNO₃ also provided high biomass and protein production. The SSF of all growth substrates was accompanied by the secretion of cellulase and xylanase activities. The highest CMCase activity (12-13 U/g) was revealed in the cultivation of P. ostreatus 2191 using wheat bran as a growth substrate and ammonium sulfate or yeast extract as a nitrogen source, whereas the highest xylanase activity was detected in the fermentation of soy flour supplemented with peptone. Acknowledgments: This work was supported by the Shota Rustaveli National Science Foundation of Georgia (Grant number STEM-22-2077).

Keywords: mushrooms, plant raw materials, fermentation, biomass protein, cellulase

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Authors: Amesh P, Suneesh A S, Venkatesan K A

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The magnetic solid-phase extraction is a relatively new method among the other solid-phase extraction techniques for the separating of metal ions from aqueous solutions, such as mine water and groundwater, contaminated wastes, etc. However, the bare magnetic particles (Fe3O4) exhibit poor selectivity due to the absence of target-specific functional groups for sequestering the metal ions. The selectivity of these magnetic particles can be remarkably improved by covalently tethering the task-specific ligands on magnetic surfaces. The magnetic particles offer a number of advantages such as quick phase separation aided by the external magnetic field. As a result, the solid adsorbent can be prepared with the particle size ranging from a few micrometers to the nanometer, which again offers the advantages such as enhanced kinetics of extraction, higher extraction capacity, etc. Conventionally, the magnetite (Fe3O4) particles were prepared by the hydrolysis and co-precipitation of ferrous and ferric salts in aqueous ammonia solution. Since the covalent linking of task-specific functionalities on Fe3O4 was difficult, and it is also susceptible to redox reaction in the presence of acid or alkali, it is necessary to modify the surface of Fe3O4 by silica coating. This silica coating is usually carried out by hydrolysis and condensation of tetraethyl orthosilicate over the surface of magnetite to yield a thin layer of silica-coated magnetite particles. Since the silica-coated magnetite particles amenable for further surface modification, it can be reacted with task-specific functional groups to obtain the functionalized magnetic particles. The surface area exhibited by such magnetic particles usually falls in the range of 50 to 150 m2.g-1, which offer advantage such as quick phase separation, as compared to the other solid-phase extraction systems. In addition, the magnetic (Fe3O4) particles covalently linked on mesoporous silica matrix (MCM-41) and task-specific ligands offer further advantages in terms of extraction kinetics, high stability, longer reusable cycles, and metal extraction capacity, due to the large surface area, ample porosity and enhanced number of functional groups per unit area on these adsorbents. In view of this, the present paper deals with the synthesis of uranium specific diethylenetriamine ligand (DETA) ligand anchored on silica-coated magnetite (Fe-DETA) as well as on magnetic mesoporous silica (MCM-Fe-DETA) and studies on the extraction of uranium from aqueous solution spiked with uranium to mimic the mine water or groundwater contaminated with uranium. The synthesized solid-phase adsorbents were characterized by FT-IR, Raman, TG-DTA, XRD, and SEM. The extraction behavior of uranium on the solid-phase was studied under several conditions like the effect of pH, initial concentration of uranium, rate of extraction and its variation with pH and initial concentration of uranium, effect of interference ions like CO32-, Na+, Fe+2, Ni+2, and Cr+3, etc. The maximum extraction capacity of 233 mg.g-1 was obtained for Fe-DETA, and a huge capacity of 1047 mg.g-1 was obtained for MCM-Fe-DETA. The mechanism of extraction, speciation of uranium, extraction studies, reusability, and the other results obtained in the present study suggests Fe-DETA and MCM-Fe-DETA are the potential candidates for the extraction of uranium from mine water, and groundwater.

Keywords: diethylenetriamine, magnetic mesoporous silica, magnetic solid-phase extraction, uranium extraction, wastewater treatment

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Authors: Asmat Nawaz, Ceylan Zafer, Ali K. Erdinc, Kaiying Wang, M. Nadeem Akram

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Hybrid halide Perovskites with the general formula ABX₃, where X = Cl, Br or I, are considered as an ideal candidates for the preparation of photovoltaic devices. The most commonly and successfully used hybrid halide perovskite for photovoltaic applications is CH₃NH₃PbI₃ and its analogue prepared from lead chloride, commonly symbolized as CH₃NH₃PbI₃_ₓClₓ. Some researcher groups are using lead free (Sn replaces Pb) and mixed halide perovskites for the fabrication of the devices. Both mesoporous and planar structures have been developed. By Comparing mesoporous structure in which the perovskite materials infiltrate into mesoporous metal oxide scaffold, the planar architecture is much simpler and easy for device fabrication. In a typical perovskite solar cell, a perovskite absorber layer is sandwiched between the hole and electron transport. Upon the irradiation, carriers are created in the absorber layer that can travel through hole and electron transport layers and the interface in between. We fabricated inverted planar heterojunction structure ITO/PEDOT/ Perovskite/PCBM/Al, based solar cell via two-step spin coating method. This is also called Sequential deposition method. A small amount of cheap additive H₂O was added into PbI₂/DMF to make a homogeneous solution. We prepared four different solution such as (W/O H₂O, 1% H₂O, 2% H₂O, 3% H₂O). After preparing, the whole night stirring at 60℃ is essential for the homogenous precursor solutions. We observed that the solution with 1% H₂O was much more homogenous at room temperature as compared to others. The solution with 3% H₂O was precipitated at once at room temperature. The four different films of PbI₂ were formed on PEDOT substrates by spin coating and after that immediately (before drying the PbI₂) the substrates were immersed in the methyl ammonium iodide solution (prepared in isopropanol) for the completion of the desired perovskite film. After getting desired films, rinse the substrates with isopropanol to remove the excess amount of methyl ammonium iodide and finally dried it on hot plate only for 1-2 minutes. In this study, we added H₂O in the PbI₂/DMF precursor solution. The concept of additive is widely used in the bulk- heterojunction solar cells to manipulate the surface morphology, leading to the enhancement of the photovoltaic performance. There are two most important parameters for the selection of additives. (a) Higher boiling point w.r.t host material (b) good interaction with the precursor materials. We observed that the morphology of the films was improved and we achieved a denser, uniform with less cavities and almost full surface coverage films but only using precursor solution having 1% H₂O. Therefore, we fabricated the complete perovskite solar cell by sequential deposition technique with precursor solution having 1% H₂O. We concluded that with the addition of additives in the precursor solutions one can easily be manipulate the morphology of the perovskite film. In the sequential deposition method, thickness of perovskite film is in µm and the charge diffusion length of PbI₂ is in nm. Therefore, by controlling the thickness using other deposition methods for the fabrication of solar cells, we can achieve the better efficiency.

Keywords: methylammonium lead iodide, perovskite solar cell, precursor composition, sequential deposition

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Authors: Mohieddine Benghersallah, Mohamed Zakaria Zahaf, Ali Medjber, Idriss Tibakh

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The objective of this study is to analyse the effects of cutting parameters on surface roughness in dry face milling using statistical techniques. We studied the effect of the microstructure of AISI 52100 steel on machinability before and after hardening. The machining tests were carried out on a high rigidity vertical milling machine with a 25 mm diameter face milling cutter equipped with micro-grain bicarbide inserts with PVD (Ti, AlN) coating in GC1030 grade. A Taguchi L9 experiment plan is adopted. Analysis of variance (ANOVA) was used to determine the effects of cutting parameters (Vc, fz, ap) on the roughness (Ra) of the machined surface. Regression analysis to assess the machinability of steel presented mathematical models of roughness and the combination of parameters to minimize it. The recorded results show that feed per tooth has the most significant effect on the surface condition for both steel treatment conditions. The best roughnesses were obtained for the hardened AISI 52100 steel.

Keywords: machinability, heat treatment, microstructure, surface roughness, Taguchi method

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Authors: Abdelsabour G. A. Khaled, Ahmed W. A. Abdalla And Sabry Y. M. Mahmoud

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Banana plants showing typical mosaic and yellow stripes on leaves as symptoms were collected from Assiut Governorate in Egypt. The causal agent was identified as Cucumber mosaic virus (CMV) on the basis of symptoms, transmission, serology, transmission electron microscopy and reverse transcription polymerase chain reaction (RT-PCR). Coat protein (CP) gene was amplified using gene specific primers for coat protein (CP), followed by cloning into desired cloning vector for sequencing. In this study the CMV was transmitted into propagation host either by aphid or mechanically. The transmission was confirmed through Direct Antigen Coating Enzyme Linked Immuno Sorbent Assay (DAC-ELISA). Analysis of the 120 deduced amino acid sequence of the coat protein gene revealed that the EG-A strain of CMV shared from 97.50 to 98.33% with those strains belonging to subgroup IA. The cluster analysis grouped the Egyptian isolate with strains Fny and Ri8 belonging sub-group IA. It appears that there occurs a high incidence of CMV infecting banana belonging to IA subgroup in most parts of Egypt.

Keywords: banana, CMV, transmission, CP gene, RT-PCR

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Authors: Violina R. Angelova, Venelina T. Popova, Radka V. Ivanova, Givko T. Ivanov, Krasimir I. Ivanov

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A comparative research on the impact of compost on uptake and allocation of nutrients and heavy metals and quality of Oriental tobacco Krumovgrad 90 has been carried out. The experiment was performed on an agricultural field contaminated by the lead zinc smelter near the town of Kardzali, Bulgaria, after closing the lead production. The compost treatments had significant effects on the uptake and allocation of plant nutrients and heavy metals. The incorporation of compost leads to decrease in the amount of heavy metals present in the tobacco leaves, with Cd, Pb and Zn having values of 36%, 12% and 6%, respectively. Application of the compost leads to increased content of potassium, calcium and magnesium in the leaves of tobacco, and therefore, may favorably affect the burning properties of tobacco. The incorporation of compost in the soil has a negative impact on the quality and typicality of the oriental tobacco variety of Krumovgrad 90. The incorporation of compost leads to an increase in the size of the tobacco plant leaves, the leaves become darker in colour, less fleshy and undergo a change in form, becoming (much) broader in the second, third and fourth stalk position. This is accompanied by a decrease in the quality of the tobacco. The incorporation of compost also results in an increase in the mineral substances (pure ash), total nicotine and nitrogen, and a reduction in the amount of reducing sugars, which causes the quality of the tobacco leaves to deteriorate (particularly in the third and fourth harvests).

Keywords: chemical composition, compost, heavy metals, oriental tobacco, quality

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Authors: Jalil Badamfirooz

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Soil wind erosion has a negative impact on the environment. Mulching is one of the most efficient soil protection techniques. Bitumen emulsion has recently been utilized as a soil cover that is sprayed directly over the soil and forms a thin film. The thin coating of bitumen emulsion prevents soil erosion and keeps moisture in the soil. Besides, some compounds release into the soil and cause environmental problems. In the present study, the effect of bitumen emulsion on the release of polycyclic aromatic hydrocarbons (PAHs) into the soil is studied in an arid land located in the central part of Iran. The soil was Loamy-Sand and saline with a pH of 8.03. Bitumen emulsion was used in this study as mulch at a rate of 4 L m2. The effect of this mulch on soil properties was investigated after 6 months of mulch application. Then PAHs concentrations were determined in samples collected from different depths in bitumen emulsion sprayed and control soils. In general, bitumen emulsion application on soil led to a significant increase in some PAHs, which was higher than soil pollution standards critical level of pollution for commerce, groundwater protection, pasture forest, and park and residence uses.

Keywords: mulch, bitumen emulsion, arid land, PAH

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Authors: Sara Gardideh, Mansoor Barati

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The mineral carbonation approach for reducing global warming has garnered interest on a worldwide scale. Due to the benefits of permanent storage and abundant mineral resources, mineral carbonation (MC) is one of the most effective strategies for sequestering CO₂. The combination of mineral processing for primary metal recovery and mineral carbonation for carbon sequestration is an emerging field of study with the potential to minimize capital costs. A detailed study of low-pressures–solid carbonation of ultramafic tailings in a dry environment has been accomplished. In order to track the changing structure of serpentine minerals and their reactivity as a function of temperature (300-900 ᵒC), CO₂ partial pressure (25-90 mol %), and thermal preconditioning, thermogravimetry has been utilized. The incongruent CO₂ van der Waals molecular diameters with the octahedral-tetrahedral lattice constants of serpentine were used to explain the mild carbonation reactivity. Serpentine requires additional thermal-treatment to remove hydroxyl groups, resulting in the chemical transformation to pseudo-forsterite, which is a mineral composed of isolated SiO₄ tetrahedra linked by octahedrally coordinated magnesium ions. The heating treatment above 850 ᵒC is adequate to remove chemically bound water from the lattice. Particles with a diameter < 34 (μm) are desirable, and thermally treated serpentine at 850 ᵒC for 2.30 hours reached 65% CO₂ storage capacity. The decrease in particle size, increase in temperature, and magnetic separation can dramatically enhance carbonation.

Keywords: particle size, thermogravimetry, thermal-treatment, serpentine

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Authors: Ming Chian Yew, Ming Kun Yew, Lip Huat Saw, Tan Ching Ng, Rajkumar Durairaj, Jing Han Beh

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This paper analyzes the fire protection performance, char formation and heat release characteristics of the thin film intumescent coatings that incorporate waste eggshell (ES) as a nano bio-filler. In this study, the Bunsen burner and the fire propagation (BS 476: Part 6) tests of coatings were measured. Experiments on the samples were also tested to evaluate their fire behavior using a cone calorimeter according to ISO 5660-1 specifications. On exposure, the samples B, C and D had been certified to be Class 0 due to the fire propagation indexes of the samples were less than 12. Samples B and D showed a significant reduction in total heat rate (B=11.6 MJ/m² and D=12.0 MJ/m²) and uniform char structures with the addition of 3.30 wt.% and 2.75 wt.% ES nano bio-filler, respectively. As a result, ES nano bio-filler composition good to slow down the fire expanding and demonstrate better fire protection due to its positive synergistic effect with flame retardant ingredients on physical and chemical reactions in fire protection.

Keywords: cone calorimeter, eggshell, fire protection, heat release rate, intumescent coating

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Authors: Galo D. Soria, Jenny S. Casame, Eddy F. Pazmino

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In Ecuador, mining operations have significantly impacted water sources. Artisanal mining extensively relies in mercury amalgamation. Mercury is a neurotoxic substance even at low concentrations. The objective of this investigation is to exploit Hg-removal capacity of sulfur-limonene polysulfide (SLP), which is a low-cost polymer, in order to prepare granular media (sand) coated with SLP to be used in laboratory scale column-filtration systems. Preliminary results achieved 85% removal of Hg⁺⁺ from synthetic effluents using 20-cm length and 5-cm diameter columns at 119m/day average pore water velocity. During elution of the column, the SLP-coated sand indicated that Hg⁺⁺ is permanently fixed to the collector surface, in contrast, uncoated sand showed reversible retention in Hg⁺⁺ in the solid phase. Injection of 50 pore volumes decreased Hg⁺⁺ removal to 46%. Ongoing work has been focused in optimizing the synthesis of SLP and the polymer content in the porous media coating process to improve Hg⁺⁺ removal and extend the lifetime of the column-filter.

Keywords: column-filter, mercury, mining, polysulfide, water treatment

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Authors: Gaurav Verma

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Organoclay loaded (0-5 weight %) polyester-urethane (PU) coatings were prepared with a branched hydroxyl-bearing polyester and an aliphatic poly-isocyanate. TEM micrographs show partial exfoliation and intercalation of clay platelets in organoclay-polyester dispersions. AFM surface images reveals that the PU hard domains tend to regularise and also self-organise into spherical shapes of sizes 50 nm (0 wt %), 60 nm (2 wt %) and 190 nm (4 wt %) respectively. IR analysis shows that PU chains have increasing tendency to interact with exfoliated clay platelets through hydrogen bonding. This interaction strengthens inter-chain linkages in PU matrix and hence improves anti-ageing properties. 1000 hours of accelerated weathering was evaluated by ATR spectroscopy, while yellowing and overall discoloration was quantified by the Δb* and ΔE* values of the CIELab colour scale. Post-weathering surface properties also showed improvement as the loss of thickness and reduction in gloss in neat PU was 25% and 42%; while it was just 3.5% and 14% respectively for the 2 wt% nanocomposite coating. This work highlights the importance of modifying surface and bulk properties of PU coatings at nanoscale, which led to improved performance in accelerated weathering conditions.

Keywords: coatings, AFM, ageing, spectroscopy

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Authors: Parvin Mirmiran, Zahra Bahadoran, Nazanin Moslehi, Fereidoun Azizi

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Background and aim: We aimed to investigate the effects of green fruits and vegetables (green FV) consumption on the 3-year changes of cardiometabolic risk factors. Methods: This longitudinal study was conducted in the framework of Tehran Lipid and Glucose Study, between 2006-2008 and 2009-2011, on 1272 adults. Dietary intake of green FV, including green cabbage, broccoli, lettuce, celery, green beans, green peas, cucumber, leafy vegetables, zucchini, green chili and bell pepper, and kiwi fruit, has been assessed by a validated semi-quantitative food frequency questionnaire at baseline and second examination. Demographics, anthropometrics and biochemical measures were evaluated at baseline and 3 years later. The associations of cardiometabolic risk changes with mean intake of green FV were estimated. Results: The mean age of men and women at baseline was 39.8±12.7 and 37.3±12.1 years, respectively. Mean intake of green FV was 152±77 g/d. More intake from green FV was accompanied to more intake of vitamin A, α and β-carotene, lutein, β-criptoxanthine, potassium, magnesium and fiber. Consumption of green FV was inversely associated with 3-year change of waist circumference (β= -0.07, P=0.01), total cholesterol (β= -0.11, P=0.01) and triglycerides (β= -0.13, P=0.01). Each 25 g/d increase in consumption of green FV decreased the incidence of hyper-triglyceridemia by 12% (OR:0.88, 95%CI:0.71-0.99) in men. In women, no significant association was observed between consumption of green FV with cardiometabolic risk factors. Conclusion: Higher consumption of green FV could have preventive effects against abdominal fat gain and lipid disorders.

Keywords: cardiometabolic risk factors, abdominal obesity, lipid disorders, fruits, vegetables

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Authors: N. Bourayou, A. -H. Meniai, A. Gouaoura

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The presence of salt can either raise or lower the distribution coefficient of a solute acetic acid in liquid- liquid equilibria. The coefficient of solute is defined as the ratio of the composition of solute in solvent rich phase to the composition of solute in diluents (water) rich phase. The phenomena are known as salting–out or salting-in, respectively. The effect of monovalent salt, sodium chloride and the bivalent salt, sodium sulfate on the distribution of acetic acid between 1-butanol and water at 298.15K were experimentally shown to be effective in modifying the liquid-liquid equilibrium of water/acetic acid/1-butanol system in favour of the solvent extraction of acetic acid from an aqueous solution with 1-butanol, particularly at high salt concentrations of both salts. All the two salts studied are found to have to salt out effect for acetic acid in varying degrees. The experimentally measured data were well correlated by Eisen-Joffe equation. NRTL model for solvent mixtures containing salts was able to provide good correlation of the present liquid-liquid equilibrium data. Using the regressed salt concentration coefficients for the salt-solvent interaction parameters and the solvent-solvent interaction parameters obtained from the same system without salt. The calculated phase equilibrium was in a quite good agreement with the experimental data, showing the ability of NRTL model to correlate salt effect on the liquid-liquid equilibrium.

Keywords: activity coefficient, Eisen-Joffe, NRTL model, sodium chloride

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Authors: L. Chetibi, D. Hamana, T. O. Busko, M. P. Kulish, S. Achour

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TiO2 nanostructures have attracted much attention due to their optical, dielectric and photocatalytic properties as well as applications including optical coating, photocatalysis and photoelectrochemical solar cells. This work aims to prepare TiO2 nanofibers (NFs) on titanium substrate (Ti) by in situ oxidation of Ti foils in a mixture solution of concentrated H2O2 and NaOH followed by proton exchange and calcinations. Scanning Electron microscopy (SEM) revealed an obvious network of TiO2 nanofibers. The photoluminescence (PL) spectra of these nanostructures revealed a broad intense band in the visible light range with a reduced near edge band emission. The PL bands in the visible region, mainly, results from surface oxygen vacancies and others defects. After irradiation with Ti+ ions (the irradiation energy was E = 140 keV with doses of 1013 ions/cm2), the intensity of the PL spectrum decreased as a consequence of the radiation treatment. The irradiation with Ti+ leads to a reduction of defects and generation of non irradiative defects near to the level of the conduction band as evidenced by the PL results. On the other hand, reducing the surface defects on TiO2 nanostructures may improve photocatalytic and optoelectronic properties of this nanostructure.

Keywords: TiO2, nanofibers, photoluminescence, irradiation

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Authors: Zainab Abbas Soharwardi, Chunli Su, Fazeelat Tahira, Syed Zahid Aziz

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The study monitors the quality of drinking water consumed by urban population of Lahore. A total of 50 drinking water samples (16 from source and 34 from distribution system) were examined for physical, chemical and bacteriological parameters. The parameters including pH, turbidity, electrical conductivity, total dissolved solids, total hardness, calcium, magnesium, total alkalinity, carbonate, sulphate, chloride, nitrite, fluoride, sodium and potassium were analyzed. Sixteen out of fifty samples showed high values of alkalinity compared to EPA standards and WHO guidelines. Twenty-eight samples were analyzed for heavy metals, chromium, iron, copper, zinc, cadmium and lead. Trace amounts of heavy metals were detected in some samples, however for most of the samples values were within the permissible limits although high concentration of zinc was detected in one sample collected from Mughal Pura area. Fifteen samples were analyzed for arsenic. The results were unsatisfactory; around 73% samples showed exceeding values of As. WHO has suggested permissible limits of arsenic < 0.01 ppm, whereas 27 % of samples have shown 0.05 ppm arsenic, which is five times greater than WHO highest permissible limits. All the samples were examined for E. coli bacteria. On the basis of bacteriological analysis, 42 % samples did not meet WHO guidelines and were unsafe for drinking.

Keywords: arsenic, heavy metals, ground water, Lahore

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Authors: Taliman Nisar Ahmad, Hirofume Saneoka

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A pot experiment was conducted to investigate the effect of phosphorus (P) and potassium (K) nutrition on grain yield, phytic acid and grain quality of high-phytate (Akimaro) and low-phytate line. Phosphorus and potassium were applied as; P₁ (20 kg ha⁻¹) and P₂ (100 kg ha⁻¹), same as K₁ (20 kg ha⁻¹) and K₂ (100 kg ha⁻¹), respectively. Low-phytate soybean had the highest grain yield, and 75% increase was observed compared to the high-phytate under same treatments. Highly significant differences of seed phytate P were observed in both cultivars, and the phytate P in high-phytate was found 39% higher than low-phytate, whereas no significant differences observed in response to P and K treatment. Percentage of phytate P from total P in seeds was 28 to 35% in low-phytate and 72 to 81% in high-phytate in different treatments. The lipid content in low-phytate was found lowered compared to that of high-phytate. Crude protein in grains was also found significantly higher in PK combined. No significant difference was observed in seed calcium (Ca), magnesium (Mg), and Zinc (Zn) in different treatments, but high-phytate showed 87% increase in seed Ca and 76% of Mg compared to low-phytate; however, low-phytate showed 82% increase in Zn content over high-phytate. The result illustrates that low-phytate soybean achieved higher grain yield and grain Pi in response to increased P and K nutrition. To achieve higher yield and quality seeds from the low-phytate soybean, it is recommended that proper phosphorus and potassium nutrition to be applied suggested in this study.

Keywords: phytic acid, low-phytate soybean, high-phytate soybean, P and K nutrition, protein content, soybean

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Authors: Janella Salamania, Marcedon Fernandez, Matthew Villanueva Henry Ramos

Abstract:

Titanium nitrite (TiN) a popular functional and decorative coating because of its golden yellow color, high hardness and superior wear resistance. It is also being studied as a diffusion barrier in integrated circuits due to its known chemical stability and low resistivity. While there have been numerous deposition methods done for TiN, most required the heating of substrates at high temperatures. In this work, TiN films are deposited on silicon (111) and (100) substrates without substrate heating using a patented magnetized sheet plasma source. Films were successfully deposited without substrate heating at various target bias, while maintaining a constant 25% N2 to Ar ratio, and deposition of time of 30 minutes. The resulting films exhibited a golden yellow color which is characteristic of TiN. X-ray diffraction patterns show the formation of TiN predominantly oriented in the (111) direction regardless of substrate used. EDX data also confirms the 1:1 stoichiometry of titanium an nitrogen. Ellipsometry measurements estimate the thickness to range from 28 nm to 33 nm. SEM images were also taken to observe the morphology of the film.

Keywords: coatings, nitrides, coatings, reactive magnetron sputtering, thin films

Procedia PDF Downloads 341

Authors: Iyagbaye O. Rich, Omoigberale O. Michael, Iyagbaye A. Louis

Abstract:

The physical, chemical parameters and some trace contents of Ugbogui in Edo State, Nigeria were investigated from August 2015 to April 2016. Four stations were studied from upstream to downstream using standard methods. A total of thirty-three (33) physical and chemical characteristics and trace metal contents were examined; Air and water temperatures, depth, transparency, colour, turbidity, flow velocity, pH, total alkalinity, conductivity and dissolved solids etc. Other includes dissolved oxygen, oxygen saturation, biochemical oxygen demand, chloride, phosphate, sodium, nitrate, sulphate, potassium, calcium, magnesium, iron, lead, copper, zinc, nickel, cadmium, vanadium and chromium. Eleven (11) parameters exhibited clear seasonal variations. However, there were high significant differences (p < 0.01) in the values of depth, colour, total suspended solid, biochemical oxygen demand, chemical oxygen demand, chloride, bicarbonate, phosphate, sulphate, iron, manganese, zinc, copper, chromium and cadmium among the stations. The anthropogenic activities had negatively impacted at station 3 of the river, although most of the recorded values were still within permissible limits.

Keywords: anthropogenic activities, Nigeria, permissible limits, physical and chemical parameters, trace metal, water quality

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Authors: Jae-Yong Park, Gwancheol Seo, Young-Ho Kim

Abstract:

Microvoids, sometimes called Kikendall voids, generally form in the interfaces between Sn-based solders and Cu and degrade the mechanical and electrical properties of the solder joints. The microvoid formation is known as the rapid interdiffusion between Sn and Cu and impurity content in the Cu. Cu electroplating from the acid solutions has been widely used by microelectronic packaging industry for both printed circuit board (PCB) and integrated circuit (IC) applications. The quality of electroplated Cu that can be optimized by the electroplating conditions is critical for the solder joint reliability. In this paper, the influence of electroplating conditions on the microvoid growth in the interfaces between Sn-3.0Ag-0.5Cu (SAC) solder and Cu layer was investigated during isothermal aging. The Cu layers were electroplated by controlling the additive of electroplating bath and current density to induce various microvoid densities. The electroplating bath consisted of sulfate, sulfuric acid, and additives and the current density of 5-15 mA/cm2 for each bath was used. After aging at 180 °C for up to 250 h, typical bi-layer of Cu6Sn5 and Cu3Sn intermetallic compounds (IMCs) was gradually growth at the SAC/Cu interface and microvoid density in the Cu3Sn showed disparities in the electroplating conditions. As the current density increased, the microvoid formation was accelerated in all electroplating baths. The higher current density induced, the higher impurity content in the electroplated Cu. When the polyethylene glycol (PEG) and Cl- ion were mixed in an electroplating bath, the microvoid formation was the highest compared to other electroplating baths. On the other hand, the overall IMC thickness was similar in all samples irrespective of the electroplating conditions. Impurity content in electroplated Cu influenced the microvoid growth, but the IMC growth was not affected by the impurity content. In conclusion, the electroplated conditions are properly optimized to avoid the excessive microvoid formation that results in brittle fracture of solder joint under high strain rate loading.

Keywords: electroplating, additive, microvoid, intermetallic compound

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Authors: Pholosho M. Kgopa, Phatu W. Mashela

Abstract:

Due to high incidents of marginal land in Limpopo Province, South Africa, and increasing demand for arable land, small-holder farmers tend to continuously cultivate the same fields and at the same time, applying fertilisers to improve yields for meeting local food security. These practices might have an impact on the distribution of trace and essential elements. Therefore, the objective of this investigation was to assess the distribution of essential elements and trace metals in a continuously cultivated and fertilised field, at the University of Limpopo Experimental Farm. Three fields, 3 ha each were identified as continuously cultivated (CC), moderately cultivated (MC) and virgin fields (VF). Each field was divided into 12 equal grids of 50 m × 50 m for sampling. A soil profile was opened in each grid, where soil samples were collected from 0-20; 20-40 and 40-60; 60-80 and 80-100 cm depths for analysis. Samples were analysed for soil texture, pH, electrical conductivity, organic matter content, selected essential elements (Ca, P and Mg), Na and trace elements (Cu, Fe, Ni, and Zn). Results suggested that most of the variables were vertically different, with high concentrations of the test elements except for magnesium. Soil pH in depth 0-20 cm was high (6.44) in CC when compared to that in VF (5.29), but lower than that of MC (7.84). There were no distinctive vertical trends of the variables, except for Mg, Na, and K which displayed a declining trend at 40-60 cm depth when compared to the 0-20 cm depth. Concentrations of Fe, Cu, Zn, and Ni were generally low which might be due to their indirect relationship with soil pH. Continuous cultivation and fertilisation altered soil chemical properties; which could explain the unproductivity of such fields.

Keywords: over-cultivation, soil chemical properties, vertical distribution, spatial distribution

Procedia PDF Downloads 188