Search results for: metal chelators

Authors: Mahsa Kangazian Kangazi, Ali Akbar Ghareh Aghaji, Majid Montazer

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Nowadays, silica nanofibers are highly regarded among the inorganic nanofibers due to the high reactivity and availability of silicon compounds in nature. Sol-gel process is required for electrospinning of silica nanofibers in which a metal alkoxide is hydrolyzed, and the viscosity is increased. In this study, silica nanofibers containing silver nanoparticles were synthesized and electrospun from a mixture of silica sol with an easy spinnable polymer (PVA) as an additive. The silica sol contains tetraethyl orthosilicate (TEOS), silver nitrate, distilled water, nitric acid, and ethanol. Nanofibers were formed through electrospinning setup. The nanofibers were calcinated to remove the solvent and additive polymer. Consequently, pure silica nanofibers were produced. FTIR analysis indicated entire removal of polyvinyl alcohol from the structure and formation of silan groups. The presence of silver, silica and oxygen was confirmed by EDX. Also, XRD patterns revealed the presence of silver nanoparticles with a mean crystal size of 18 nm. FESEM images showed that adding silver nitrate into the sol-gel, resulted in lower nanofibers diameter from 286 to 136 nm. Furthermore, the electrospun nanofibers were more resistance in acidic media than alkaline media.

Keywords: in situ synthesis of silver nanoparticles, silica nanofibers, sol-gel, tetraethyl orthosilicate

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Authors: Kianoosh Shojae

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In recent years, the environmental challenges due to the excessive use of fossil fuels have led to heightened greenhouse gas production. In response, biodiesel has emerged as a cleaner alternative, offering reduced pollutant emissions compared to traditional fuels. The large-scale production of biodiesel, involving ester exchange of animal fats or vegetable oils, results in a surplus of crude glycerin. With environmental regulations on the rise and an increasing demand for biodiesel, glycerin production has seen a significant upswing. This paper focuses on the economic significance of glycerin through its pyrolysis as a raw material, particularly in the synthesis of metals. As industries pivoted towards cleaner fuels, glycerin, as a byproduct of biodiesel production, is poised to remain a cost-effective and surplus product. In this work, for evaluating the possible performance of using the gaseous products from the pyrolysis reaction of glycerol, we concerned the glycerin pyrolysis reactions, emphasizing the catalytic role of activated carbon, various reaction pathways and the impact of carrier gas flow rate on hydrogen production, providing valuable insights into the evolving landscape of sustainable fuel alternatives.

Keywords: biodiesel, glycerin pyrolysis, activated carbon catalysis, syngas

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Authors: Iryna P. Dzieciuch, Michael D. Putman

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Humidity is known to degrade Navy ship electronic equipment, especially in hot moist environments. If left untreated, it can cause significant and permanent damage. Even rigorous inspection and frequent clean-up would not prevent further equipment contamination and degradation because of the constant presence of favorable growth conditions for many microorganisms. Generally, relative humidity levels of less than 60% will inhibit corrosion in electronic equipment, but because NAVY electronics often operate in hot and humid environments, prevention via dehumidification is not always possible. Currently, there is no defined research that fully describes key mechanisms which cause electronics and its coating degradation. The corrosive action of most bacteria is mainly developed through (i) mycelium adherence to the metal plates, (ii) facilitation the formation of pitting areas, (iii) production of organic acids such as citric, iso-citric, cis-aconitic, alpha-ketoglutaric, which are corrosive to electronic equipment and its components. Our approach studies corrosive action in electronic equipment: circuit-board, wires and connections that are exposed in the humid environment that gets worse during condensation. In our new approach the technical task is built on work with the bacterial communities in public areas, bacterial genetics, bioinformatics, biostatistics and Scanning Electron Microscopy (SEM) of corroded circuit boards. Based on these methods, we collect and examine environmental samples from biofilms of the corroded and non-corroded sites, where bacterial contamination of electronic equipment, such as machine racks and shore boats, is an ongoing concern. Sample collection and sample analysis is focused on addressing the key questions identified above through the following tasks: laboratory sample processing and evaluation under scanning electron microscopy, initial sequencing and data evaluation; bioinformatics and data analysis. Preliminary results from scanning electron microscopy (SEM) have revealed that metal particulates and alloys in corroded samples consists mostly of Tin ( < 40%), Silicon ( < 4%), Sulfur ( < 1%), Aluminum ( < 2%), Magnesium ( < 2%), Copper ( < 1%), Bromine ( < 2%), Barium ( <1%) and Iron ( < 2%) elements. We have also performed X 12000 magnification of the same sites and that proved existence of undisrupted biofilm organelles and crystal structures. Non-corrosion sites have revealed high presence of copper ( < 47%); other metals remain at the comparable level as on the samples with corrosion. We have performed X 1000 magnification on the non-corroded at the sites and have documented formation of copper crystals. The next step of this study, is to perform metagenomics sequencing at all sites and to compare bacterial composition present in the environment. While copper is nontoxic to the living organisms, the process of bacterial adhesion creates acidic environment by releasing citric, iso-citric, cis-aconitic, alpha-ketoglutaric acidics, which in turn release copper ions Cu++, which that are highly toxic to the bacteria and higher order living organisms. This phenomenon, might explain natural “antibiotic” properties that are lacking in elements such as tin. To prove or deny this hypothesis we will use next - generation sequencing (NGS) methods to investigate types and growth cycles of bacteria that from bacterial biofilm the on corrosive and non-corrosive samples.

Keywords: bacteria, biofilm, circuit board, copper, corrosion, electronic equipment, organic acids, tin

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Authors: Sucharat Limsitthichaikoon, Kedsarin Saodaeng, Aroonsri Priprem, Teerasak Damrongrungruang

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Complexation of anthocyanins to mimic natural copigmentation process was investigated. Cyanidin-rich extracts from Zea mays L. CeritinaKulesh. anddelphinidin-rich extracts from ClitoriaternateaL. were used to form 4 anthocyanin complexes, AC1, AC2, AC3, and AC4, in the presence of several polyphenols and a trace metal. Characterizations of the ACs were conducted by UV, FTIR, DSC/TGA and morphological observations. Bathochromic shifts of the UV spectra of 4 formulas of ACs were observed at peak wavelengths of about 510-620 nm by 10 nm suggesting complex formation.FTIR spectra of the ACs indicate shifts of peaks from 1,733 cm-1 to 1,696 cm-1 indicating interactions and a decrease in the peak areas within the wavenumber of 3,400-3,500 cm-1 indicating changes in hydrogen bonding.Thermal analysis of all of the ACs suggests increases in melting temperature after complexation. AC with the highest melting temperature was morphologically observed by SEM and TEM to be crystal-like particles within a range of 50 to 200 nm. Particle size analysis of the AC by laser diffraction gave a range of 50-600 nm, indicating aggregation. This AC was shown to have no cytotoxic effect on cultured HGEPp0.5 and HGF (all p> 0.05) by MTT. Therefore, complexation of anthocyanins was simple and self-assembly process, potentially resulting in nanosized particles of anthocyanin complex.

Keywords: anthocyanins, complexation, purple corn cops, butterfly pea, physicochemical characteristics, cytotoxicity

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Authors: B. Manoj Kumar, C. Malavika, E. S. Kannan

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The objective of this study is to investigate the switching behavior of two vertically aligned memristors connected by a shared top electrode, a configuration that significantly deviates from the conventional single oxide layer sandwiched between two electrodes. The device is fabricated by bridging copper electrodes with mechanically exfoliated van der Waals metal (specifically tantalum disulfide and tantalum diselenide). The device demonstrates threshold-switching behavior in its I-V characteristics. When the input voltage signal is ramped with voltages below the threshold, the output current shows spiking behavior, resembling integrated and firing actions without extra circuitry. We also investigated the self-reset behavior of the device. Using a continuous constant voltage bias, we activated the device to the firing state. After removing the bias and reapplying it shortly afterward, the current returned to its initial state. This indicates that the device can spontaneously return to its resting state. The outcome of this investigation offers a fresh perspective on memristor-based device design and an efficient method to construct hardware for neuromorphic computing systems.

Keywords: integrated and firing, memristor, spiking behavior, threshold switching

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Authors: Bhavesh N. Bhatt, Zozimus D. Labana

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This work is mainly focused on the analysis of heat transfer of blade by using internal cooling method. By using conjugate heat transfer technology we can effectively compute the cooling and heat transfer analysis of blade. Here blade temperature is limited by materials melting temperature. By using CFD code, we will analyze the blade cooling with the help of CHT method. There are two types of CHT methods. In the first method, we apply coupled CHT method in which all three domains modeled at once, and in the second method, we will first model external domain and then, internal domain of cooling channel. Ten circular cooling channels are used as a cooling method with different mass flow rate and temperature value. This numerical simulation is applied on NASA C3X turbine blade, and results are computed. Here results are showing good agreement with experimental results. Temperature and pressure are high at the leading edge of the blade on stagnation point due to its first faces the flow. On pressure side, shock wave is formed which also make a sudden change in HTC and other parameters. After applying internal cooling, we are succeeded in reducing the metal temperature of blade by some extends.

Keywords: gas turbine, conjugate heat transfer, NASA C3X Blade, circular film cooling channel

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Authors: H. Özkan Gülsoy, Antonyraj Arockiasamy

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The application of powder injection molding technology for the fabrication of metallic and non-metallic components is of growing interest as the process considerably saves time and cost. Utilizing this fabrication method, full dense components are being prepared in various sizes. In this work, our effort is focused to study the densification behavior of the parts made using different size 316L stainless steel powders. The metal powders were admixed with an adequate amount of polymeric compounds and molded as standard tensile bars. Solvent and thermal debinding was carried out followed by sintering in ultra pure hydrogen atmosphere based on the differential scanning calorimetry (DSC) cycle. Mechanical property evaluation and microstructural characterization of the sintered specimens was performed using universal Instron tensile testing machine, Vicker’s microhardness tester, optical (OM) and scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction were used. The results are compared and analyzed to predict the strength and weakness of the test conditions.

Keywords: powder injection molding, sintering, particle size, stainless steels

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Authors: Jose Neri, Fabrice Canto, Alastair Magnaldo, Laurent Guillerme, Vincent Dugas

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A miniaturized and automated approach for the volumetric titration of free nitric acid in U(VI) solutions is presented. Free acidity measurement refers to the acidity quantification in solutions containing hydrolysable heavy metal ions such as U(VI), U(IV) or Pu(IV) without taking into account the acidity contribution from the hydrolysis of such metal ions. It is, in fact, an operation having an essential role for the control of the nuclear fuel recycling process. The main objective behind the technical optimization of the actual ‘beaker’ method was to reduce the amount of radioactive substance to be handled by the laboratory personnel, to ease the instrumentation adjustability within a glove-box environment and to allow a high-throughput analysis for conducting more cost-effective operations. The measurement technique is based on the concept of the Taylor-Aris dispersion in order to create inside of a 200 μm x 5cm circular cylindrical micro-channel a linear concentration gradient in less than a second. The proposed analytical methodology relies on the actinide complexation using pH 5.6 sodium oxalate solution and subsequent alkalimetric titration of nitric acid with sodium hydroxide. The titration process is followed with a CCD camera for fluorescence detection; the neutralization boundary can be visualized in a detection range of 500nm- 600nm thanks to the addition of a pH sensitive fluorophore. The operating principle of the developed device allows the active generation of linear concentration gradients using a single cylindrical micro channel. This feature simplifies the fabrication and ease of use of the micro device, as it does not need a complex micro channel network or passive mixers to generate the chemical gradient. Moreover, since the linear gradient is determined by the liquid reagents input pressure, its generation can be fully achieved in faster intervals than one second, being a more timely-efficient gradient generation process compared to other source-sink passive diffusion devices. The resulting linear gradient generator device was therefore adapted to perform for the first time, a volumetric titration on a chip where the amount of reagents used is fixed to the total volume of the micro channel, avoiding an important waste generation like in other flow-based titration techniques. The associated analytical method is automated and its linearity has been proven for the free acidity determination of U(VI) samples containing up to 0.5M of actinide ion and nitric acid in a concentration range of 0.5M to 3M. In addition to automation, the developed analytical methodology and technique greatly improves the standard off-line oxalate complexation and alkalimetric titration method by reducing a thousand fold the required sample volume, forty times the nuclear waste per analysis as well as the analysis time by eight-fold. The developed device represents, therefore, a great step towards an easy-to-handle nuclear-related application, which in the short term could be used to improve laboratory safety as much as to reduce the environmental impact of the radioanalytical chain.

Keywords: free acidity, lab-on-a-chip, linear concentration gradient, Taylor-Aris dispersion, volumetric titration

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Authors: Anton Trník, Lenka Scheinherrová, Robert Černý

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Silica fume is a by-product of the ferro-silicon and silicon metal industries. It is mainly in the form of amorphous silica. Silica fume belongs to pozzolanic active materials which can be used in concrete to improve its final properties. In this paper, the influence of silica fume on hydration of cement pastes is studied using differential scanning calorimetry (DSC) and thermogravimetry (TG) at various curing times (2, 7, 28, and 90 days) in the temperature range from 25 to 1000 °C in an argon atmosphere. Samples are prepared from Portland cement CEM I 42.5 R which is partially replaced with the silica fume of 4, 8, and 12 wt.%. The water/binder ratio is chosen as 0.5. It is identified and described the liberation of physically bound water, calcium–silicate–hydrates dehydration, portlandite and calcite decomposition in studied samples. Also, it is found out that an exothermic peak at 950 °C is observed without a significant mass change for samples with 12 wt.% of silica fume after two days of hydration. This peak is probably caused by the pozzolanic reaction between silica fume and Portland cement. Its size corresponds to the degree of crystallization between Ca and Si. The portlandite content is lower for the samples with a higher amount of silica fume.

Keywords: differential scanning calorimetry, hydration, silica fume, thermogravimetry

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Authors: Amina Sriba

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In this work, interactions between the chemical elements forming the passive film of welded austenitic stainless steel during pitting corrosion are studied. We pay special attention to the chemical elements chromium, molybdenum, iron, nickel, and silicon since they make up the passive film that covers the fusion zone's surface in the welded joint. Molybdenum and chromium are typically the two essential components that control the three crucial stages of pit formation. It was found that while the involvement of chromium is more prominent during the propagation of a pit that has already begun, the enrichment of the molybdenum element in the passive film becomes apparent from the first stage of pit initiation. Additionally, during the pitting corrosion process, there was a noticeable fluctuation in the quantities of the produced oxides and hydroxide species from zone to zone. Regarding the formed hydroxide species, we clearly see that Nickel hydroxides are added to those of Chromium to constitute the outer layer in the passive film of the fusion zone sample, compared to the base metal sample, where only Chromium hydroxide formed on its surface during the pitting corrosion process. This reaction is caused by the preferential dissolution of the austenite phase instead of ferrite in the fusion zone.

Keywords: fusion zone, passive film, chemical elements, pit

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Authors: Gopal Ji, Priyanka Dwivedi, Shanthi Sundaram, Rajiv Prakash

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Inhibition effect of aqueous Argemone Mexicana root extract (AMRE) on mild steel corrosion in 1 M HCl has been studied by weight loss, Tafel polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Results indicate that inhibition ability of AMRE increases with the increasing amount of the extract. A maximum corrosion inhibition of 94% is acknowledged at the extract concentration of 400 mg L-1. Polarization curves and impedance spectra reveal that both cathodic and anodic reactions are suppressed due to passive layer formation at metal-acid interface. It is also confirmed by SEM micro graphs and FTIR studies. Furthermore, the effects of acid concentration (1-5 M), immersion time (120 hours) and temperature (30-60˚C) on inhibition potential of AMRE have been investigated by weight loss method and electrochemical techniques. Adsorption mechanism is also proposed on the basis of weight loss results, which shows good agreement with Langmuir isotherm.

Keywords: mild steel, polarization, SEM, acid corrosion, EIS, green inhibition

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Authors: S. A. M. Sabrina, Gouget Lammel, Anne Chantal, Chazalviel, Jean Noël, Ozanam François, Etcheberry Arnaud, Tighlit Fatma Zohra, B. Samia, Gabouze Noureddine

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The elaboration and characterization of hybrid nano materials give rise to considerable interest due to the new properties that arising. They are considered as an important category of new materials having innovative characteristics by combining the specific intrinsic properties of inorganic compounds (semiconductors) with the grafted organic species. This open the way to improved properties and spectacular applications in various and important fields, especially in the environment. In this work, nano materials based-semiconductors were elaborated by chemical route. The obtained surfaces were grafted with organic functional groups. The functionalization process was optimized in order to confer to the hybrid nano material a good stability as well as the right properties required for the subsequent applications. Different characterization techniques were used to investigate the resulting nano structures, such as SEM, UV-Visible, FTIR, Contact angle and electro chemical measurements. Finally, applications were envisaged in environmental area. The elaborated nano structures were tested for the detection and the elimination of pollutants.

Keywords: hybrid materials, porous silicon, peptide, metal detection

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Authors: A. Deswal, N. S. Deora, H. N. Mishra

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The aim of the present study was to develop a rapid method for electronic nose for online quality control of oat milk. Analysis by electronic nose and bacteriological measurements were performed to analyse spoilage kinetics of oat milk samples stored at room temperature and refrigerated conditions for up to 15 days. Principal component analysis (PCA), discriminant factorial analysis (DFA) and soft independent modelling by class analogy (SIMCA) classification techniques were used to differentiate the samples of oat milk at different days. The total plate count (bacteriological method) was selected as the reference method to consistently train the electronic nose system. The e-nose was able to differentiate between the oat milk samples of varying microbial load. The results obtained by the bacteria total viable counts showed that the shelf-life of oat milk stored at room temperature and refrigerated conditions were 20 hours and 13 days, respectively. The models built classified oat milk samples based on the total microbial population into “unspoiled” and “spoiled”.

Keywords: electronic-nose, bacteriological, shelf-life, classification

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Authors: Kiurski S. Jelena, Ranogajec G. Jonjaua, Kecić S. Vesna, Oros B. Ivana

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The present study investigates the effectiveness of newly designed clayey pellets (fired clay pellets diameter sizes of 5 and 8 mm, and unfired clay pellets with the diameter size of 15 mm) as the beds in the column adsorption process. The adsorption experiments in the batch mode were performed before the column experiment with the purpose to determine the order of adsorbent package in the column which was to be designed in the investigation. The column experiment was performed by using a known mass of the clayey beds and the volume of the waste printing developer, which was purified. The column was filled in the following order: fired clay pellets of the diameter size of 5 mm, fired clay pellets of the diameter size of 8 mm, and unfired clay pellets of the diameter size of 15 mm. The selected order of the adsorbents showed a high removal efficiency for zinc (97.8%) and copper (81.5%) ions. These efficiencies were better than those in the case of the already existing mode adsorption. The obtained experimental data present a good basis for the selection of an appropriate column fill, but further testing is necessary in order to obtain more accurate results.

Keywords: clay materials, fix bed adsorption column, metal ions, printing developer

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Authors: B. Guezzen, M.A. Didi, B. Medjahed

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A factorial design of experiments and a response surface methodology were implemented to investigate the liquid-liquid extraction process of zinc (II) from acetate medium using the 1-Butyl-imidazolium di(2-ethylhexyl) phosphate [BIm⁺][D2EHP^-]. The optimization process of extraction parameters such as the initial pH effect (2.5, 4.5, and 6.6), ionic liquid concentration (1, 5.5, and 10 mM) and salt effect (0.01, 5, and 10 mM) was carried out using a three-level full factorial design (3³). The results of the factorial design demonstrate that all these factors are statistically significant, including the square effects of pH and ionic liquid concentration. The results showed that the order of significance: IL concentration > salt effect > initial pH. Analysis of variance (ANOVA) showing high coefficient of determination (R² = 0.91) and low probability values (P < 0.05) signifies the validity of the predicted second-order quadratic model for Zn (II) extraction. The optimum conditions for the extraction of zinc (II) at the constant temperature (20 °C), initial Zn (II) concentration (1mM) and A/O ratio of unity were: initial pH (4.8), extractant concentration (9.9 mM), and NaCl concentration (8.2 mM). At the optimized condition, the metal ion could be quantitatively extracted.

Keywords: ionic liquid, response surface methodology, solvent extraction, zinc acetate

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Authors: I. Inthanongsone, C. Drebenstedt, J. C. Bongaerts, P. Sontamino

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The major concern in evaluating the value of mining projects related to the deficiency of the traditional discounted cash flow (DCF) method. This method does not take uncertainties into account and, hence it does not allow for an economic assessment of managerial flexibility and operational adaptability, which are increasingly determining long-term corporate success. Such an assessment can be performed with the real options valuation (ROV) approach, since it allows for a comparative evaluation of unforeseen uncertainties in a project life cycle. This paper presents an economic evaluation model for open pit mining projects based on real options valuation approach. Uncertainties in the model are caused by metal prices and cost uncertainties and the system dynamics (SD) modeling method is used to structure and solve the real options model. The model is applied to a case study. It can be shown that that managerial flexibility reacting to uncertainties may create additional value to a mining project in comparison to the outcomes of a DCF method. One important insight for management dealing with uncertainty is seen in choosing the optimal time to exercise strategic options.

Keywords: DCF methods, ROV approach, system dynamics modeling methods, uncertainty

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Authors: Md. Hasan Zahir

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Y2O3-doped silica membranes were synthesized with the sol-gel method by using a tetraethyl orthosilicate-derived sol mixed with yttrium nitrate hexahydrate. These solutions were used to fabricate hydrogen separation microporous membranes with a sandwich-type structure on γ-Al2O3 supported by tubular α-Al2O3. Pore size distribution measurements were conducted directly on the membranes before and after hydrothermal treatment with a nano-permporometer. The gas permeance properties of the membranes were measured in the temperature range 100–500°C. The Y-doped SiO2 membrane (Si/Y = 3/1) was found to exhibit asymptotically stable permeances of 2.39×10-7 mol m-2 s -1 Pa-1 for He and 6.19 ×10-10 mol m-2 s -1 Pa-1 for CO2, with a high selectivity of 386 (He/CO2) at 500°C for 20 h in the presence of steam. The Y-doped silica membranes exhibit very high gas permeances for molecules with smaller kinetic diameters. The apparent activation energies of the H2 permeance at 400°C were 24.2±0.2 and 21.3±0.7 kJ mol−1 for SiO2 and Si/Y, respectively. Very high permeances were obtained for N2 and O2, 2.2 and 5 × 10-8 mol m-2 s -1 Pa-1 respectively, which demonstrates that these materials are promising air purification and/or separation systems that block larger impurity molecules by molecular sieving effects. Y-doped SiO2 exhibits greater hydrothermal stability at high temperatures and higher selectivity than SiO2 membranes.

Keywords: ceramic membrane, gas separation, hydrothermal stability, rare earth doped-Silica

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Authors: Fernanda A. Vechietti, Natália O. B. Muniz, Laura C. Treccani, Kurosch. Rezwan, Luis Alberto dos Santos

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CoCr alloys are widely used in prosthetic implants due to their excellent mechanical properties, such as good tensile strength, elastic modulus and wear resistance. Their biocompatibility and lack of corrosion are also prominent features of this alloy. One of the most effective and simple ways to protect metal’s surfaces are treatments, such as electrochemical oxidation by passivation, which is used as a protect release of metallic ions. Another useful treatment is the electropolishing, which is used to reduce the carbide concentration and protrusion at the implanted surface. Electropolishing is a cheap and effective method for treatment of implants, which generally has complex geometries. The purpose of this study is surface modification of the alloy CoCr(ASTM F90-09) by different methods: polishing, electro polishing, passivation and heat treatment for application as biomaterials. The modification of the surface was studied and characterized by SEM, profilometry, wettability and compared to the surface of the samples untreated. The heat treatment and of passivation increased roughness (0.477 µm and 0.825 µm) the samples in relation the sample electropolished and polished(0.131 µm and 0.274 µm) and were observed the improve wettability’s with the increase the roughness.

Keywords: biomaterial, CoCr, surface treatment, heat treatment, roughness

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Authors: Jeong-Hyun Yoo, Hanjung Kwon, Sung-Wook Cho

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Fused salt electrolysis was studied to make the high purity rare-earth metals using domestic rare-earth ore. The target metals of the fused salt electrolysis were Mm (Misch metal), La, Ce, Nd, etc. Fused salt electrolysis was performed with the supporting salt such as chloride and fluoride at the various temperatures and ampere. The metals made by fused salt electrolysis were analyzed to identify the phase and composition using the methods of XRD and ICP. As a result, the acquired rare-earth metals were the high purity ones which had more than 99% purity. Also, VIM (vacuum induction melting) was studied to make the kg level rare-earth alloy for the use of secondary battery and hydrogen storage. In order to indentify the physicochemical properties such as phase, impurity gas, alloy composition and hydrogen storage, the alloys were investigated. The battery characteristics were also analyzed through the various tests in the real production line of a battery company.

Keywords: domestic rare-earth ore, fused salt electrolysis, rare-earth materials, hydrogen storage alloy, secondary battery

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Authors: Imene Atek, Abed M. Affoune, Hubert Girault, Pekka Peljo

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Due to the need for a rigorous mathematical model that can help to estimate kinetic properties for soluble-insoluble systems, through voltammetric experiments, a Nicholson Semi Analytical Approach was used in this work for modeling and prediction of theoretical linear sweep voltammetry responses for reversible, quasi reversible or irreversible electron transfer reactions. The redox system of interest is a one-step metal electrodeposition process. A rigorous analysis of simulated linear scan voltammetric responses following variation of dimensionless factors, the rate constant and charge transfer coefficients in a broad range was studied and presented in the form of the so called kinetic zones diagrams. These kinetic diagrams were divided into three kinetics zones. Interpreting these zones leads to empirical mathematical models which can allow the experimenter to determine electrodeposition reactions kinetics whatever the degree of reversibility. The validity of the obtained results was tested and an excellent experiment–theory agreement has been showed.

Keywords: electrodeposition, kinetics diagrams, modeling, voltammetry

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Authors: Olaitan Akanji, Cleophas Loto, Patricia Popoola, Andrei Kolesnikov

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Studies involving performance of corrosion inhibitors had been identified as one of the critical research needs for improving the durability of mild steel used in various industrial applications. This paper investigates the inhibiting effect of calcium gluconate against the corrosion of mild steel in 2.5M magnesium chloride using weight loss method and linear polarization technique, calculated corrosion rates from the obtained weight loss data, potentiodynamic polarization measurements are in good agreement. Results revealed calcium gluconate has strong inhibitory effects with inhibitor efficiency increasing with increase in inhibitor concentration at ambient temperature, the efficiency of the inhibitor increased in the following order of concentrations 2%g/vol,1.5%g/vol,1%g/vol,0.5%g/vol. Further results obtained from potentiodynamics experiments had good correlation with those of the gravimetric methods, the adsorption of the inhibitor on the mild steel surface from the chloride has been found to obey Langmuir, Frumkin and Freudlich adsorption isotherm. Scanning electron microscopy (SEM) observation confirmed the existence of an absorbed protective film on the metal surface.

Keywords: calcium gluconate, corrosion, magnesium chloride, mild steel

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Authors: Bilge Demir, Ahmet Durgutlu, Mustafa Acarer

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In this study, the butt welding of the commercial AZ31 magnesium alloy sheets have been carried out by using Tungsten Inert Gas (TIG) welding process with alternative and pulsed current. Welded samples were examined with regards to hardness and microstructure. Despite some recent developments in welding of magnesium alloys, they have some problems such as porosity, hot cracking, oxide formation and so on. Samples of the welded parts have undergone metallographic and mechanical examination. Porosities and homogeneous micron grain oxides were rarely observed. Orientations of the weld microstructure in terms of heat transfer also were rarely observed and equiaxed grain morphology was dominant grain structure as in the base metal. As results, fusion zone and few locations of the HAZ of the welded samples have shown twin’s grains. Hot cracking was not observed for any samples. Weld bead geometry of the welded samples were evaluated as normal according to welding parameters. In the results, conditions of alternative and pulsed current and the samples were compared to each other with regards to microstructure and hardness.

Keywords: AZ31 magnesium alloy, microstructures, micro hardness TIG welding

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Authors: Roshni Raha, Kavya P., Gayathri M.

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India, with a humongous population, remains the world's poorest developing nation in terms of nutritional status, with iron deficiency anaemia (IDA) affecting the population. Despite efforts over the past decades, India's anaemia prevalence has not been reduced. Researchers are interested in developing therapies that will minimize the typical side effects of oral iron and optimize iron salts-based treatment through delivery methods based on the physiology of hepcidin regulation. However, they need to come up with iron therapies that will prevent making the infection worse. This article explores using bio-nanotechnology as the alternative, promising substitution of providing iron supplements for the treatment of diarrhoea and gut inflammation in kids and pregnant women. This article is an exploratory study using a literature survey and secondary research from review papers. In the realm of biotechnology, nanoparticles have become extremely famous due to unexpected variations in surface characteristics caused by particle size. Particle size distribution and shape exhibit unusual, enhanced characteristics when reduced to nanoscale. The article attempts to develop a model for a nanotechnology based solution in iron fortification to combat the problems of diarrhoea and gut inflammation. Certain dimensions that have been considered in the model include the size, shape, source, and biosynthesis of the iron nanoparticles. Another area of investigation addressed in the article is the cost-effective biocompatible production of these iron nanoparticles. Studies have demonstrated that a substantial reduction of metal ions to form nanoparticles from the bulk metal occurs in plants because of the presence of a wide diversity of biomolecules. Using this concept, the paper investigates the effectiveness and impact of how similar sources can be used for the biological synthesis of iron nanoparticles. Results showed that iron particles, when prepared in nano-metre size, offer potential advantages. When the particle size of the iron compound decreases and attains nano configuration, its surface area increases, which further improves its solubility in the gastric acid, leading to higher absorption, higher bioavailability, and producing the least organoleptic changes in food. It has no negative effects and possesses a safe, effective profile to reduce IDA. Considering all the parameters, it has been concluded that iron particles in nano configuration serve as alternative iron supplements for the complete treatment of IDA. Nanoparticles of ferric phosphate, ferric pyrophosphate, and iron oxide are the choices of iron supplements. From a sourcing perspective, the paper concludes green sources are the primary sources for the biological synthesis of iron nanoparticles. It will also be a cost-effective strategy since our goal is to treat the target population in rural India. Bio-nanotechnology serves as an alternative and promising substitution for iron supplements due to its low cost, excellent bioavailability, and strong organoleptic properties. One area of future research can be to explore the type of size and shape of iron nanoparticles that would be suitable for the different age groups of pregnant women and children and whether it would be influenced based on the topography in certain areas.

Keywords: anemia, bio-nanotechnology, iron-fortification, nanoparticle

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Authors: Bi Wa, Su-Yeon Kwon, Ik-Joong Kang

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Surface-enhanced Raman Scattering (SERS) as the principle for enhancing Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures is used to detect the concentration change of γ-Aminobutyric Acid (GABA). GABA is the mainly inhibitory neurotransmitter in the mammalian central nervous system in the human body. It plays such significant role in reducing neuronal excitability throughout the nervous system. In this case, the Mercaptopropionic Acid (MPA) is used to modified chitosan –gold nanoshell, which enhances the absorption between GABA and Chitosan-gold nanoshell. The sulfur end of the MPA is linked to gold which is the surface of the chitosan nanoparticles via the very strong S–Au bond, while a functional group (carboxyl group) attached to GABA. The controlling of particles’ size and the surface morphology are also the important factors during the whole experiment. The particle around 100nm is using to link to MPA, and the range of GABA from 1mM to 30mM was detected by the Raman Scattering to obtain the calibrate curve. In this study, DLS, SEM, FT-IR, UV, SERS were used to analyze the products to obtain the conclusion.

Keywords: chitosan-gold nanoshell, mercaptopropionic acid, γ-aminobutyric acid, surface-enhanced raman scattering

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Authors: Nivedha L. K., Dhinesh Kumar Murugaiah, Ganapathi Rao Kandregula, Raja Murugan, Kothandaraman R.

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ZnMn₂O₄, a non-precious metal catalyst for oxygen reduction reaction (ORR), was recycled from the spent primary Zn-C battery and utilized in the zinc-air battery. Catalysts exhibiting facile ORR kinetics are a requirement for building efficient Zinc-air batteries. ZnMn₂O₄ demonstrated excellent catalytic activity towards ORR in an aqueous alkaline medium, with an onset potential of 0. 90 V vs. RHE. The recycled ZnMn₂O₄ manifested a similar performance (at ~ 1.0 V) as the chemically synthesized one with a specific capacity of 210 mAh gzn-¹ at a constant current discharge of 15 mA cm-². A single electrode potential study was done to comprehend the losses at the electrodes and to identify the limiting electrode. Interestingly, the cathode was improving during discharge, which is in contrast to the expectation due to the accumulation of peroxide around the catalytic layer. Although the anode has exhibited minimal polarization, beyond a capacity of 210 mAh g-¹, the supersaturation of electrolyte occurs with zincate ion causing precipitation of ZnO on the cell components, thereby leading to sudden polarization of the cell and hence zinc electrode act as a limiting electrode in this system.

Keywords: battery recycling, oxygen reduction reaction, single electrode measurement, Zn-air battery, ZnMn₂O₄ recovery

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Authors: A. Asselah, A. Khalfi, M. A.Toumi, A.Tazerouti

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The study of the corrosion inhibition of a standard carbon steel "API 5L grade X70" by two biodegradable anionic surfactants derived from fatty acids by photo sulfochlorination, called sodium lauryl methyl ester sulfonates and sodium palmityl methyl ester sulfonates was carried. A solution at 2.5 g/l NaCl saturated with carbon dioxide is used as a corrosive medium. The gravimetric and electrochemical technics (stationary and transient) were used in order to quantify the rate of corrosion and to evaluate the electrochemical inhibition efficiency, thus the nature of the mode of action of the inhibitor, in addition to a surface characterization by scanning electron microscopy (MEB) coupled to energy dispersive X-ray spectroscopy (EDX). The variation of the concentration and the temperature were examined, and the mode of adsorption of these inhibitors on the surface of the metal was established by assigning it the appropriate isotherm and determining the corresponding thermodynamic parameters. The MEB-EDX allowed the visualization of good adhesion of the protective film formed by the surfactants to the surface of the steel. The corrosion inhibition was evaluated at around 93% for sodium lauryl methyl ester sulfonate surfactant at 20 ppm and 87.2% at 50 ppm for sodium palmityl methyl ester sulfonate surfactant.

Keywords: carbon steel, oilfield, corrosion, anionic surfactants

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Authors: A. A. Hassani, M. Nasri Nasrabadi

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According to population growth and increasing water needs of industrial and agricultural sections and lack of existing water sources, also increases of wastewater and new wastewater treatment plant construction’s high costs, it is inevitable to reuse wastewater with the approach of increasing wastewater treatment capacity and output sewage quality. In this regard, the first sewage reuse plan in industrial uses was designed with the approach of qualitative and quantitative improvement due to the increased organic load of the output sewage of Qom Shokohieh city’s’ in wastewater treatment plant. This research investigated qualitative factors COD, BOD, TSS, TDS, and input and output heavy metal of MBR-RO system and ability of increase wastewater acceptance capacity by existing in wastewater treatment plant. For this purpose, experimental results of seven-month navigation system have been used from 07/01/2013 to 02/01/2014. Existing data analysis showed that MBR system is able to remove 93.2% COD, 94.4% BOD, 13.8% TDS, 98% heavy metals and RO system is able to remove 98.9% TDS. This study showed that MBR-RO integration system is able to increase the capacity of refinery by 30%.

Keywords: industrial wastewater, wastewater reuse, MBR, RO

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Authors: Amandeep Kaur, Sangeeta Sharma

Abstract:

Keeping in view the serious entanglement of heavy metals ( Pb+2 and Ni+2) ions in an aqueous environment, a rapid search for efficient adsorbents for the adsorption of heavy metals has become highly desirable. In this quest, green synthesized Fe np’s have gathered attention because of their excellent adsorption capability of heavy metals from aqueous solution. This research report aims at the fabrication of Fe np’s using the fruit Cucumis melo and leaves of Ficus virens via a biogenic synthesis route. Further, synthesized CM-Fe-np’s and FV-Fe-np’s have been tested as potential bio-adsorbents for the removal of Pb+2 and Ni+2 by carrying out adsorption batch experiments. The influence of myriad parameters like initial concentration of Pb/Ni (5,10,15,20,25 mg/L), contact time (10 to 200 min.), adsorbent dosage (0.5, 0.10, 0.15 mg/L), shaking speed (120 to 350 rpm) and pH value (6,7,8,9) has been investigated. The maximum removal with CM-Fe-np’s and FV-Fe-np’s has been achieved at pH 7, metal conc. 5 mg/L, dosage 0.9 g/L, shaking speed 200 rpm and reaction contact time 200 min during the adsorption experiment. The results obtained are found to be in accordance with Freundlich and Langmuir's adsorption models; consequently, they could be highly applicable to the wastewater treatment plant.

Keywords: adsorption, biogenic synthesis, nanoparticles, nickel, lead

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Authors: Prashant Dhiman, Viranshu Kumar, Pradeep Joshi

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Lot of research is going on to study the effect of cryogenic treatment on materials. Cryogenic treatment is a heat treatment process which is used widely to enhance the mechanical and metallurgical properties of various materials whether the material is ferrous or non ferrous. In almost all ferrous metals, it is found that retained austenite is converted into martensite. Generally deep cryogenic treatment is done using liquid nitrogen having temperature of -195 ℃. The austenite is unstable at this stage and converts into martensite. In non ferrous materials there presents a microcavity and under the action of stress it becomes crack. When this crack propagates, fracture takes place. As the metal contract under low temperature, by doing cryogenic treatment these microcavities will be filled hence increases the soundness of the material. Properties which are enhanced by cryogenic treatment of both ferrous and non ferrous materials are hardness, tensile strength, wear rate, electrical and thermal conductivity, and others. Also there is decrease in residual stress. A large number of manufacturing process (EDM, CNC etc.) are using cryogenic treatment on different tools or workpiece to reduce their wear. In this Review paper the use of cryogenic heat treatment in different manufacturing has been shown along with their advantages.

Keywords: cyrogenic treatment, EDM (Electrical Discharge Machining), CNC (Computer Numeric Control), Mechanical and Metallurgical Properties

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Authors: Thandie Veronicah Sima, Moatlhodi Wiseman Letshwenyo

Abstract:

Discharge of wastewater is one of the major sources of phosphorus entering streams, lakes and other water bodies causing undesired environmental problem such as eutrophication. This condition not only puts the ecosystem at risk but also causes severe economic damages. Stringent laws have been developed globally by different bodies to control the level of phosphorus concentrations into receiving environments. In order to satisfy the constraints, a high degree of tertiary treatment or at least a significant reduction of phosphorus concentration is obligatory. This comprehensive review summarizes phosphorus removal technologies, from the most commonly used conventional technologies such as chemical precipitation through metal addition, membrane filtration, reverse osmosis and enhanced biological phosphorus removal using activated sludge system to passive systems such as constructed wetlands and filtration systems. Trends, perspectives and scientific procedures conducted by different researchers have been presented. This review critically evaluates the advantages and limitations behind each of the technologies. Enhancement of passive systems using reactive media such as industrial wastes to provide additional uptake through adsorption or precipitation is also discussed in this article.

Keywords: adsorption, chemical precipitation, enhanced biological phosphorus removal, phosphorus removal

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