Search results for: heavy metal resistance

Authors: Hasan Türe, Kader Terzioglu, Evren Tunca

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Contamination of aqueous environment by heavy metal ions is a serious and complex problem, owing to their hazards to human being and ecological systems. The treatment methods utilized for removing metal ions from aqueous solution include membrane separation, ion exchange and chemical precipitation. However, these methods are limited by high operational cost. Recently, biobased beads are considered as promising biosorbent to remove heavy metal ions from water. The aim of present study was to characterize the alginate/perlite composite beads and to investigate the adsorption performance of obtained beads for removing Pb (II) from aqueous solution. Alginate beads were synthesized by ionic gelation methods and different amount of perlite (aljinate:perlite=1, 2, 3, 4, 5 wt./wt.) was incorporated into alginate beads. Samples were characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). The effects of perlite level, the initial concentration of Pb (II), initial pH value of Pb(II) solution and effect of contact time on the adsorption capacity of beads were investigated by using batch method. XRD analysis indicated that perlite includes silicon or silicon and aluminum bearing crystalline phase. The diffraction pattern of perlite containing beads is similar to that of that perlite powder with reduced intensity. SEM analysis revealed that perlite was embedded into alginate polymer and SEM-EDX (Energy-Dispersive X-ray) showed that composite beads (aljinate:perlite=1) composed of C (41.93 wt.%,), O (43.64 wt.%), Na (10.20 wt.%), Al (0.74 wt.%), Si (2.72 wt.%) ve K (0.77 wt.%). According to TGA analysis, incorporation of perlite into beads significantly improved the thermal stability of the samples. Batch experiment indicated that optimum pH value for Pb (II) adsorption was found at pH=7 with 1 hour contact time. It was also found that the adsorption capacity of beads decreased with increases in perlite concentration. The results implied that alginate/perlite composite beads could be used as promising adsorbents for the removal of Pb (II) from wastewater. Acknowledgement: This study was supported by TUBITAK (Project No: 214Z146).

Keywords: alginate, adsorption, beads, perlite

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Authors: A. A. Adebayo, O. Osibanjo

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Informal electronic waste (e-waste) processing is a crude method of recycling, which is on the increase in Nigeria. The release of hazardous substances such as heavy metals (HMs) into the environment during informal e-waste processing has been a major concern. However, there is insufficient information on environmental contamination from e-waste recycling, associated ecological risk in Alaba International Market, a major electronic market in Lagos, Nigeria. The aims of this study were to determine the levels of HMs in soil, resulting from the e-waste recycling; and also assess associated ecological risks in Alaba international market. Samples of soils (334) were randomly collected seasonally for three years from fourteen selected e-waste activity points and two control sites. The samples were digested using standard methods and HMs analysed by inductive coupled plasma optical emission. Ecological risk was estimated using Ecological Risk index (ER), Potential Ecological Risk index (RI), Index of geoaccumulation (Igeo), Contamination factor (Cf) and degree of contamination factor (Cdeg). The concentrations range of HMs (mg/kg) in soil were: 16.7-11200.0 (Pb); 14.3-22600.0 (Cu); 1.90-6280.0 (Ni), 39.5-4570.0 (Zn); 0.79-12300.0 (Sn); 0.02-138.0 (Cd); 12.7-1710.0 (Ba); 0.18-131.0 (Cr); 0.07-28.0 (V), while As was below detection limit. Concentrations range in control soils were 1.36-9.70 (Pb), 2.06-7.60 (Cu), 1.25-5.11 (Ni), 3.62-15.9 (Zn), BDL-0.56 (Sn), BDL-0.01 (Cd), 14.6-47.6 (Ba), 0.21–12.2 (Cr) and 0.22-22.2 (V). The trend in ecological risk index was in the order Cu > Pb > Ni > Zn > Cr > Cd > Ba > V. The potential ecological risk index with respect to informal e-waste activities were: burning > dismantling > disposal > stockpiling. The index of geo accumulation indices revealed that soils were extremely polluted with Cd, Cu, Pb, Zn and Ni. The contamination factor indicated that 93% of the studied areas have very high contamination status for Pb, Cu, Ba, Sn and Co while Cr and Cd were in the moderately contaminated status. The degree of contamination decreased in the order of Sn > Cu > Pb >> Zn > Ba > Co > Ni > V > Cr > Cd. Heavy metal contamination of Alaba international market environment resulting from informal e-waste processing was established. Proper management of e-waste and remediation of the market environment are recommended to minimize the ecological risks.

Keywords: Alaba international market, ecological risk, electronic waste, heavy metal contamination

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Authors: Y. Hajjam, I. T. Alami, S. M. Udupa, S. Cherkaoui

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Faba bean (Vicia faba L.) is an important food legume crop in Morocco. It is mainly used as human food and feed for animals. Faba bean also plays an important role in cereal-based cropping systems, when rotated with cereals it improves soil fertility by fixing N2 in root nodules mediated by Rhizobium. Both faba bean and its biological nitrogen fixation symbiotic bacterium Rhizobium are affected by different stresses such as: salinity, drought, pH, heavy metal, and the uptake of inorganic phosphate compounds. Therefore, the aim of the present study was to evaluate the phenotypic diversity among the faba bean rhizobial isolates and to select the tolerant strains that can fix N2 under environmental constraints for inoculation particularly for affected soils, in order to enhance the productivity of faba bean and to improve soil fertility. Result have shown that 62% of isolates were fast growing with the ability of producing acids compounds , while 38% of isolates are slow growing with production of alkalins. Moreover, 42.5% of these isolates were able to solubilize inorganic phosphate Ca3(PO4)2 and the index of solubilization was ranged from 2.1 to 3.0. The resistance to extreme pH, temperature, water stress heavy metals and antibiotics lead us to classify rhizobial isolates into different clusters. Finally, the authentication test under greenhouse conditions showed that 55% of the rhizobial isolates could induce nodule formation on faba bean (Vicia faba L.) under greenhouse experiment. This phenotypic characterization may contribute to improve legumes and non legumes crops especially in affected soils and also to increase agronomic yield in the dry areas.

Keywords: rhizobia, vicia faba, phenotypic characterization, nodule formation, environmental constraints

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Authors: Roisul H. Galib, Prabhakar R. Bandaru

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In 2D material based device, an interface between 2D materials and substrates often limits the heat flow through the device. In this paper, we quantify the total thermal resistance of a graphene-based device by series resistance model and show that the thermal resistance at the interface of graphene and substrate contributes to more than 50% of the total resistance. Weak Van der Waals interactions at the interface and dissimilar phonon vibrational modes create this thermal resistance, allowing less heat to flow across the interface. We compare our results with commonly used materials and interfaces, demonstrating the role of the interface as a potential application for heat guide or block in a 2D material-based device.

Keywords: 2D material, graphene, thermal conductivity, thermal conductance, thermal resistance

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Authors: Nurzaki Ikhsan, Ahmad Saifizul Abdullah, Rahizar Ramli

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One of the functions of the commercial heavy vehicle is to safely and efficiently transport goods and people. Due to its size and carrying capacity, it is important to study the vehicle dynamic stability during cornering. Study has shown that there are a number of overloaded heavy vehicles or permissible gross vehicle weight (GVW) violations recorded at selected areas in Malaysia assigned by its type and category. Thus, the objective of this study is to investigate the correlation and effect of the GVW on heavy vehicle stability during cornering event using simulation. Various selected heavy vehicle types and category are simulated using IPG/Truck Maker® with different GVW and road condition (coefficient of friction of road surface), while the speed, driver characteristic, center of gravity of load and road geometry are constant. Based on the analysis, the relationship between GVW and lateral acceleration were established. As expected, on the same value of coefficient of friction, the maximum lateral acceleration would be increased as the GVW increases.

Keywords: heavy vehicle, road safety, vehicle stability, lateral acceleration, gross vehicle weight

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Authors: M. S. Said, J. A. Ghani, C. H. Che Hassan, N. N. Wan, M. A. Selamat, R. Othman

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Metal Matrix Composite (MMCs) have attracted considerable attention as a result of their ability to provide high strength, high modulus, high toughness, high impact properties, improved wear resistance and good corrosion resistance than unreinforced alloy. Aluminium Silicon (Al/Si) alloys Metal Matrix composite (MMC) has been widely used in various industrial sectors such as transportation, domestic equipment, aerospace, military, construction, etc. Aluminium silicon alloy is MMC reinforced with aluminium nitride (AlN) particle and becomes a new generation material for automotive and aerospace applications. The AlN material is one of the advanced materials with light weight, high strength, high hardness and stiffness qualities which have good future prospects. However, the high degree of ceramic particles reinforcement and the irregular nature of the particles along the matrix material that contribute to its low density, is the main problem that leads to the machining difficulties. This paper examines tool wear when milling AlSi/AlN Metal Matrix Composite using a TiB2 coated carbide cutting tool. The volume of the AlN reinforced particle was 10%. The milling process was carried out under dry cutting condition. The TiB2 coated carbide insert parameters used were the cutting speed of (230 m/min, feed rate 0.4mm tooth, DOC 0.5mm, 300 m/min, feed rate 0.8mm/tooth, DOC 0.5mm and 370 m/min, feed rate 0.8, DOC 0.4m). The Sometech SV-35 video microscope system was used for tool wear measurements respectively. The results have revealed that the tool life increases with the cutting speed (370 m/min, feed rate 0.8 mm/tooth and depth of cut 0.4mm) constituted the optimum condition for longer tool life which is 123.2 min. While at medium cutting speed, it is found that the cutting speed of 300m/min, feed rate 0.8 mm/tooth and depth of cut 0.5mm only 119.86 min for tool wear mean while the low cutting speed give 119.66 min. The high cutting speed gives the best parameter for cutting AlSi/AlN MMCs materials. The result will help manufacture to machining the AlSi/AlN MMCs materials.

Keywords: AlSi/AlN Metal Matrix Composite milling process, tool wear, TiB2 coated carbide tool, manufacturing engineering

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Authors: Mayowa Philips Ibitola, Akinade-Solomon Olorunfemi, Abe Oluwaseun Banji

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Heavy minerals studies were carried out on eighteen sediment samples from Ologe lagoon located at Lagos Barrier complex, with the aim of evaluating the heavy mineral deposits and determining the provenance of the sediments. The samples were subjected to grain analysis techniques in order to collect the finest grain size. Separation of heavy minerals from the samples was done with the aid of bromoform to enable petrographic analyses of the heavy mineral suite, under the polarising microscope. The data obtained from the heavy mineral analysis were used in preparing histograms and pie chart, from which the individual heavy mineral percentage distribution and ZTR index were derived. The percentage composition of the individual heavy mineral analyzed are opaque mineral 63.92%, Zircon 12.43%, Tourmaline 5.79%, Rutile 13.44%, Garnet 1.74% and Staurolite 3.52%. The calculated zircon, tourmaline, rutile index in percentage (ZTR) varied between 76.13 -92.15%, average garnet-zircon index (GZI), average rutile-zircon index (RuZI) and average staurolite-zircon index values in all the stations are 16.18%, 54.33%, 25.11% respectively. The mean ZTR index percentage value is 85.17% indicates that the sediments within the lagoon are mineralogically matured. The high percentage of zircon, rutile, and tourmaline indicates an acid igneous rock source for the sediments. However, the low percentage of staurolite, rutile and garnet occurrence indicates sediment of metamorphic rock source input.

Keywords: lagoon, provenance, heavy mineral, ZTR index

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Authors: Mohammad Mahdi Mohammadi

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Zinc-coated steel sheets have been joined with aluminum samples in an overlapping as well as in a butt-joint configuration. A bi-metal-wire composed from aluminum and steel was used for additional welding experiments. An advantage of the laser-assisted bi-metal-wire welding is that the welding process is simplified since the primary joint between aluminium and steel exists already and laser welding occurs only between similar materials. FEM-simulations of the process were chosen to determine the ideal dimensions with respect to the formability of the bi-metal-wire. A prototype demonstrated the feasibility of the process.

Keywords: car body, steel sheets, formability of bi-metal-wire, laser-assisted bi-metal-wire

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Authors: V. Sai Geethika, Sai Snehitha Yadavalli, Swati Ghosh Acharyya

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This study involves a single element and simultaneous electrochemical detection of heavy metal ions through square wave anodic stripping voltammetry. A glassy carbon electrode was used to detect and quantify heavy metals such as As(III), Hg(II), Cr(VI) ions in water. Under optimized conditions, peak separation was obtained by varying concentrations, scan rates, and temperatures. As (III), Hg (II), Cr (III) were simultaneously detected with GCE. Several analytical methods, such as inductively coupled plasma mass spectroscopy (ICP-MS), atomic absorption spectroscopy (AAS), were used previously to detect heavy metal ions, which are authentic but are not good enough for online monitoring due to the bulkiness of the equipment. The study provides a good alternative that is simple, more efficient, and low-cost, involving a portable potentiostat. Heavy metals having different oxidation states can be detected by anodic stripping voltammetry. This method can be easily integrated with electronics. Square wave Anodic stripping voltammetry is used with a potential range of -2.5 V – 2.5 V for single ion detection by a three-electrode cell consisting of silver/silver chloride(Ag/AgCl) as reference and platinum (Pt) counter and glassy carbon (GCE) working electrodes. All three ions are optimized by varying the parameters like concentration, scan rate, pH, temperature, and all these optimized parameters were used for studying the effects of simultaneous detection. The procedure involves preparing an electrolyte using deionized water, cleaning the surface of GCE, depositing the ions by applying the redox potentials obtained from cyclic voltammetry (CV), and then detecting by applying oxidizing potential, i.e., stripping voltage. So this includes ASV techniques such as open-circuit voltage (OCV), chronoamperometry (CA), and square wave voltammetry (SWV). Firstly, the concentration of the ions varied from 50 ppb to 5000 ppb, and an optimum concentration was determined where the three ions were detected. A concentration of 400 ppb was used while varying the temperatures in the range of 25°C – 45°C. Optimum peak intensity was obtained at a temperature of 30°C with a low scan rate of 0.005 V-s⁻¹. All the parameters were optimized, and several effects have been noticed while three ions As(II), Cr(III), Hg(II) were detected alone and simultaneously.

Keywords: Arsenic(III), Chromium(III), glassy carbon electrode, Mercury (II), square wave anodic stripping voltammetry

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Authors: Thirupathi Thippani, Kothandaraman Ramanujam

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Current research on energy storage has been paid to metal-air batteries, because of attractive alternate energy source for the future. Metal – air batteries have the probability to significantly increase the power density, decrease the cost of energy storage and also used for a long time due to its high energy density, low-level pollution, light weight. The performance of these batteries mostly restricted by the slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on cathode during battery discharge and charge. The ORR and OER are conventionally carried out with precious metals (such as Pt) and metal oxides (such as RuO₂ and IrO₂) as catalysts separately. However, these metal-based catalysts are regularly undergoing some difficulties, including high cost, low selectivity, poor stability and unfavorable to environmental effects. So, in order to develop the active, stable, corrosion resistance and inexpensive bi-functional catalyst material is mandatory for the commercialization of zinc-air rechargeable battery technology. We have attempted and synthesized non-precious metal (NPM) catalysts comprising cobalt and N-doped multiwalled carbon nanotubes (N-MWCNTs-Co) were synthesized by the solid-state pyrolysis (SSP) of melamine with Co₃O₄. N-MWCNTs-Co acts as an excellent electrocatalyst for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), and hence can be used in secondary metal-air batteries and in unitized regenerative fuel cells. It is important to study the OER and ORR at high concentrations of KOH as most of the metal-air batteries employ KOH concentrations > 4M. In the first 16 cycles of the zinc-air battery while using N-MWCNTs-Co, 20 wt.% Pt/C or 20 wt.% IrO₂/C as air electrodes. In the ORR regime (the discharge profile of the zinc-air battery), the cell voltage exhibited by N-MWCNTs-Co was 44 and 83 mV higher (based on 5th cycle) in comparison to of 20 wt.% Pt/C and 20 wt.% IrO₂/C respectively. To demonstrate this promise, a zinc-air battery was assembled and tested at a current density of 0.5 Ag⁻¹ for charge-discharge 100 cycles.

Keywords: oxygen reduction reaction (ORR), oxygen evolution reaction(OER), non-platinum, zinc air battery

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Authors: Fanyuan Shao, Wei Liu, Deli Gao

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Polycrystalline diamond composite (PDC) cutter is made of diamond powder as raw material, cobalt metal or non-metallic elements as a binder, mixed with WC cemented carbide matrix assembly, through high temperature and high-pressure sintering. PDC bits with PDC cutters are widely used in oil and gas drilling because of their high hardness, good wear resistance and excellent impact toughness. And PDC cutter is the main cutting tool of bit, which seriously affects the service of the PDC bit. The wear resistance of the PDC cutter is measured by cutting granite with a vertical turret lathe (VTL). This experiment can achieve long-distance cutting to obtain the relationship between the wear resistance of the PDC cutter and cutting distance, which is more closely to the real drilling situation. Load cell and 3D optical profiler were used to obtain the value of cutting forces and wear area, respectively, which can also characterize the damage and wear of the PDC cutter. PDC cutters were cut via electrical discharge machining (EDM) and then flattened and polished. A scanning electron microscope (SEM) was used to observe the distribution of binder cobalt and the size of diamond particles in a diamond PDC cutter. The cutting experimental results show that the wear area of the PDC cutter has a good linear relationship with the cutting distance. Simultaneously, the larger the wear area is and the greater the cutting forces are required to maintain the same cutting state. The size and distribution of diamond particles in the polycrystalline diamond layer have a great influence on the wear resistance of the diamond layer. And PDC cutter with fine diamond grains shows more wear resistance than that with coarse grains. The deep leaching process is helpful to reduce the effect of binder cobalt on the wear resistance of the polycrystalline diamond layer. The experimental study can provide an important basis for the application of PDC cutters in oil and gas drilling.

Keywords: polycrystalline diamond compact, scanning electron microscope, wear resistance, cutting distance

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Authors: Jiancheng Zheng

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When metals are released into water from mining activities, they undergo changes chemically, physically and biologically and then may become more mobile and transportable along the waterway from their original sites. Natural colloids, including both organic and inorganic entities, are naturally occurring in any aquatic environment with sizes in the nanometer range. Natural colloids in a water system play an important role, quite often a key role, in binding and transporting compounds. When assessing and evaluating metals in natural waters, their sources, mobility, fate, and distribution patterns in the system are the major concerns from the point of view of assessing environmental contamination and pollution during resource development. There are a few ways to quantify colloids and accordingly study how metals distribute on different sizes of colloids. Current research results show that the presence of colloids can enhance the transport of some heavy metals in water, while heavy metals may also have an influence on the transport of colloids when cations in the water system change colloids and/or the ion strength of the water system changes. Therefore, studies into the relationship between different sizes of colloids and different metals in a water system are necessary and needed as natural colloids in water systems are complex mixtures of both organic and inorganic as well as biological materials. Their stability could be sensitive to changes in their shapes, phases, hardness and functionalities due to coagulation and deposition et al. and chemical, physical, and biological reactions. Because metal contaminants’ adsorption on surfaces of colloids is closely related to colloid properties, it is desired to fraction water samples as soon as possible after a sample is taken in the natural environment in order to avoid changes to water samples during transportation and storage. For this reason, this study carried out groundwater sample processing in the field, using Prep/Scale tangential flow filtration systems with 3-level cartridges (1 kDa, 10 kDa and 100 kDa). Groundwater samples from seven sites at Fort MacMurray, Alberta, Canada, were fractionated during the 2015 field sampling season. All samples were processed within 3 hours after samples were taken. Preliminary results show that although the distribution pattern of metals on colloids may vary with different samples taken from different sites, some elements often tend to larger colloids (such as Fe and Re), some to finer colloids (such as Sb and Zn), while some of them mainly in the dissolved form (such as Mo and Be). This information is useful to evaluate and project the fate and mobility of different metals in the groundwaters and possibly in environmental water systems.

Keywords: metal, colloid, groundwater, mobility, fractionation, sorption

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Authors: Ali Moarrefzadeh

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In metalworking, rolling is a metal forming process in which metal stock is passed through a pair of rolls. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes. This article describes the use of advanced tubing inspection NDT methods for boiler and heat exchanger equipment in the petrochemical industry to supplement major turnaround inspections. The methods presented include remote field eddy current, magnetic flux leakage, internal rotary inspection system and eddy current.

Keywords: hot forming, cold forming, metal, rolling, simulation

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Authors: Gi-Beom Park, Hyong-Gi Park, Seong-Yong Lee, Jaeho Choi, Seok Hong Min, Tae Kwon Ha

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The Nb silicide-based alloy has the excellent high-temperature strength and relatively lower density than the Ni-based superalloy; therefore, it has been receiving a lot of attention for the next generation high-temperature material. To enhance the high temperature creep property and oxidation resistance, Si was added to the Nb-based alloy, resulting in a multi-phase microstructure with metal solid solution and silicide phase. Since the silicide phase has a low machinability due to its brittle nature, it is necessary to fabricate components using the powder metallurgy. However, powder manufacturing techniques for the alloys have not yet been developed. In this study, we tried to fabricate Nb-based alloy powder by the hydrogenation-dehydrogenation reaction. The Nb-based alloy ingot was prepared by vacuum arc melting and it was annealed in the hydrogen atmosphere for the hydrogenation. After annealing, the hydrogen concentration was increased from 0.004wt% to 1.22wt% and Nb metal phase was transformed to Nb hydride phase. The alloy after hydrogenation could be easily pulverized into powder by ball milling due to its brittleness. For dehydrogenation, the alloy powders were annealed in the vacuum atmosphere. After vacuum annealing, the hydrogen concentration was decreased to 0.003wt% and Nb hydride phase was transformed back to Nb metal phase.

Keywords: Nb alloy, Nb metal and silicide composite, powder, hydrogenation-dehydrogenation reaction

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Authors: Bahaa Eltahawy, Mikko Ylihärsilä, Reino Virrankoski, Esko Petäjä

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Sheet metal processing is automated, but the step from product models to the production machine control still requires human intervention. This may cause time consuming bottlenecks in the production process and increase the risk of human errors. In this paper we present a system, which automatically recognizes features from the CAD-model of the sheet metal product. By using these features, the system produces a complete model of the particular sheet metal product. Then the model is used as an input for the sheet metal processing machine. Currently the system is implemented, capable to recognize more than 11 of the most common sheet metal structural features, and the procedure is fully automated. This provides remarkable savings in the production time, and protects against the human errors. This paper presents the developed system architecture, applied algorithms and system software implementation and testing.

Keywords: feature recognition, automation, sheet metal manufacturing, CAD, CAM

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Authors: Girlie D. Leopoldo, Myrna S. Ceniza, Ronnie L. Besagas, Antonio Y. Asoy, Noel T. Dael, Romeo M. Del Rosario

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The quality of groundwater from main deep well sources of seven (7) municipalities in Western Misamis Oriental, Philippines was examined. The study looks at the well waters’ physicochemical properties (temperture, pH, turbidity, conductivity, TDS, salinity, chlorides, TOC, and total hardness), the heavy metals and other metals (Pb, Cd, Al, As, Hg, Sb, Zn, Cu, Fe) and their microbiological (total coliform and E. coli) characteristics. The physicochemical properties of groundwater samples were found to be within the Philippine National Standards for Drinking Water (PNSDW)/US-EPA except for the TDS, chlorides, and hardness of some sources. Well waters from both Initao and Gitagum municipalities have TDS values of 643.2 mg/L and 578.4 mg/L, respectively, as compared to PNSDW/US-EPA standard limit of 500 mg/L. These same two municipalities Initao and Gitagum as well as the municipality of Libertad also have chloride levels beyond the 250 mg/L limit of PNSDW/US-EPA/EU with values at 360, 318 and 277 mg/L respectively. The Libertad sample also registered a total hardness of 407.5 mg/L CaCO3 as compared to the 300 mg/L PNSDW limit. These mentioned three (3) municipalities are noticed to have similar geologic structures. Although metal analyses revealed the presence of Zn, Cu and Fe in almost all well water sources, their concentrations are below allowable limit. All well waters from the seven municipalities failed in total coliform count. Escherichia coli were also found in well waters from four (4) municipalities including Laguindingan, Lugait, Gitagum, and Libertad. The presence of these pathogens in the well waters needs to be addressed to make the waters suitable for human consumption.

Keywords: groundwater, deep well, physico-chemical, heavy metal, microbiological

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Authors: Saima Nasreen, Uzaira Rafique, Shery Ehrman, Muhammad Aqeel Ashraf

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The release of heavy metals into the environment is a potential threat to water and soil quality as well as to plant, animal and human health. In current research work, organically functionalized mesoporous silicates (MSU-H) were prepared by the co-condensation between sodium silicate and oregano alkoxysilanes in the presence of the nonionic surfactant triblock copolymer P104. The surfactant was used as a template for improving the porosity of the hybrid gels. Synthesized materials were characterized by TEM, FT-IR, SEM/EDX, TG, surface area analysis. The surface morphology and textural properties of such materials varied with various kinds of groups in the channels. In this study, removal of some heavy metals ions from aqueous solution by adsorption process was investigated. Batch adsorption studies show that the adsorption capacity of metal ions on the functionalized silicates is more than that on pure MSU-H. Data shows adsorption on synthesized materials is a time efficient process, suggesting adsorption on external surface as well as the mesoporous process. Adsorption models of Langmuir, Freundlich, and Temkin depicted equal goodness for all adsorbents, whereas pseudo 2nd order kinetics is in best agreement with experimental data.

Keywords: heavy metals, mesoporous silica, hybrid, adsorption, freundlich, langmuir, temkin

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Authors: Lydia Andrade, Kumar M. R. Bhat

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Heavy metals, especially lead, is considered to be a multi-organ toxicant. However, such heavy metals, are used in the preparation of traditional medicines. Nagabhasma is one of the traditional medicines. Lead is the metal used in its preparation. Lead is converted into a health beneficial, organometallic compound, when subjected to various traditional methods of purification. Therefore, this study is designed to evaluate the effect of such processed lead in various stages of traditionally prepared Nagabhasma on the histological structure of kidneys. Using the human equivalent doses of Nagabhasma, various stages of its preparation were fed orally for 30 days and 60 days (short term and long term). The treated and untreated rats were then sacrificed for the collection of kidneys. The kidneys were processed for histopathological study. The results show severe changes in the histological structure of kidneys. The animals treated with lead acetate showed changes in the epithelial cells lining the bowman’s capsule. The proximal and distal convoluted tubules were dilated leading to atrophy of their epithelial cells. The amount of inflammatory infiltrates was more in this group. A few groups also showed pockets of inter-tubular hemorrhage. These changes, however, were minimized as the stages progressed form stages 1 to 4 of Nagabhasma preparation. Therefore, it is necessary to stringently monitor the processing of lead acetate during the preparation of Nagabhasma.

Keywords: heavy metals, kidneys, lead acetate, Nagabhasma

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Authors: P. Charvin, R. Bourrou, F. Lemont, C. Lafon, A. Russello

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For nuclear waste treatment and confinement, a specific IN-CAN melting module based on low-frequency induction heating have been designed. The frequency of 50Hz has been chosen to improve penetration length through metal. In this design, the liquid metal, strongly stirred by electromagnetic effects, presents shape of a dome caused by strong Laplace forces developing in the bulk of bath. Because of a lower density, the glass phase is located above the metal phase and is heated and stirred by metal through interface. Electric parameters (Intensity, frequency) give precious information about metal load and composition (resistivity of alloy) through impedance modification. Then, power supply can be adapted to energy transfer efficiency for suitable process supervision. Modeling of this system allows prediction of metal dome shape (in agreement with experimental measurement with a specific device), glass and metal velocity, heat and motion transfer through interface. MHD modeling is achieved with COMSOL and Fluent. First, a simplified model is used to obtain the shape of the metal dome. Then the shape is fixed to calculate the fluid flow and the thermal part.

Keywords: electromagnetic stirring, induction heating, interface modeling, metal load

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Authors: Suad M. Abuzariba, M. Gazette

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To test for the presence of toxic heavy metals, specifically Arsenic, Lead, and Mercury in formula milk available in Misrata city north of Libya for infants aged 6-12 months through Atomic Absorption Spectrophotometer,30 samples of imported milk formula in Libyan markets subjected to test to accurate their pollution with heavy metals, We get concentration of Hg, Ar, Pb in milk formula samples was between 0.002-1.37, 1.62-0.04–2.16, 0.15–0.65 respectively, when compared the results with Libyan &WHO standards ,they were within standards of toxic heavy metals. The presence or absence of toxic heavy metals (Lead, Arsenic, and Mercury) in selected infant formula milk and their levels within or beyond standards set by the WHO. The three infant formulas tested, all were negative for Arsenic and Lead, while two out of the three infant formulas tested positive for Mercury with levels of 0.6333ppm and 0.8333ppm. The levels of Mercury obtained, expressed in parts per million (ppm), from the two infant formulas tested were above the Provisional Tolerable Weekly Intake of total Mercury, which is 0.005ppm, as set by the FAO, WHO, and JECFA.

Keywords: heavy metals, milk formula, Libya, toxic

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Authors: Salim Al Jadidi, Shian Gao, Shivananda Moolya

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Computational Fluid Dynamic (CFD) technique coupled with Sub-Grid-Scale (SGS) model is used to study the flow behavior of heavy oil-water-air flow in a horizontal pipe by adapting ANSYS Fluent CFD software. The technique suitable for the transport of water-lubricated heavy viscous oil in a horizontal pipe is the Core Annular flow (CAF) technique. The present study focuses on the numerical study of CAF adapting Large Eddy Simulations (LES). The basic objective of the present study is to gain a basic knowledge of the flow behavior of heavy oil using turbulent CAF through a conventional horizontal pipe. This work also focuses on the success and applicability of LES. The simulation of heavy oil-water-air three-phase flow and two-phase flow of heavy oil–water in a conventional horizontal pipe is performed using ANSYS Fluent 16.2 software. The influence of three-phase heavy oil-water air flow in a selected pipe is affected by gravity. It is also observed from the result that the air phase and the variation in the temperature impact the behavior of the annular stream and pressure drop. Some results obtained during the study are validated with the results gained from part of the literature experiments and simulations, and the results show reasonably good agreement between the studies.

Keywords: computational fluid dynamics, gravity, heavy viscous oil, three-phase flow

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Authors: Nedal N. Marei, Nashaat Nassar

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Many treatment techniques have been used to remove the soluble pollutants from wastewater as; dyes and metal ions which could be found in rich amount in the used water of the textile and tanneries industry. The effluents from these industries are complex, containing a wide variety of dyes and other contaminants, such as dispersants, acids, bases, salts, detergents, humectants, oxidants, and others. These techniques can be divided into physical, chemical, and biological methods. Adsorption has been developed as an efficient method for the removal of heavy metals from contaminated water and soil. It is now recognized as an effective method for the removal of both organic and inorganic pollutants from wastewaters. Nanosize materials are new functional materials, which offer high surface area and have come up as effective adsorbents. Nano alumina is one of the most important ceramic materials widely used as an electrical insulator, presenting exceptionally high resistance to chemical agents, as well as giving excellent performance as a catalyst for many chemical reactions, in microelectronic, membrane applications, and water and wastewater treatment. In this study, methylene blue (MB) dye has been used as model dye of textile wastewater in order to synthesize a synthetic MB wastewater. NiO nanoparticles were added in small percentage in the sand packed bed adsorption columns to remove the MB from the synthetic textile wastewater. Moreover, different parameters have been evaluated; flow of the synthetic wastewater, pH, height of the bed, percentage of the NiO to the sand in the packed material. Different mathematical models where employed to find the proper model which describe the experimental data and help to analyze the mechanism of the MB adsorption. This study will provide good understanding of the dyes adsorption using metal oxide nanoparticles in the classical sand bed.

Keywords: adsorption, column, nanoparticles, methylene

Procedia PDF Downloads 238

Authors: Sumayah Mohammed Asiri A., Aviva Levina B., Elizabeth New C., Peter Lay D.

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Pt compounds have been among the most successful anticancer drugs in the last 40 years, but the development of resistance to them is an increasing problem. Cellular homeostasis of an essential metal, Cu, is known to be involved in Pt resistance, but mechanisms of this process are poorly understood. We used a novel ratiometric Cu(I)-sensitive fluorescent probeInCCu1 dye to detect Cu(I) in the mitochondria. Total Cu and labile Cu pool measured using AAS and InCCu1 dye in A2780 cells and their corresponding resistant cells A2780-cis.R cells treated with Cu and cisplatin. The main difference between both cell lines in the presence and absence of Cu(II) is that resistant cells have lower total Cu content but higher labile Cu levels than cisplatin-sensitive cells. This means that resistant cells can metabolize and export excess Cu more efficiently. Furthermore, InCCu1 has emerged not only as an indicator of labile cellular Cu levels in the mitochondria but as a potentially versatile multi-organelle probe.

Keywords: AAS and ICPMS, A2780 and its resistant cells, ratiometric fluorescent sensors, inCCu1, and total and labile Cu

Procedia PDF Downloads 180

Authors: A. Md. Bayejid Hosen, B. M Zakir Hossain Howlader, C. Yearul Kabir

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Contamination of soil and agricultural products by heavy metals resulting from rapid industrial development has caused major concern. Dietary exposure to heavy metals has been associated with toxic and adverse health effects. The main threats to human health from heavy metals are associated with exposure to Pb, Cd and Hg. The aim of this study was to monitor the presence of heavy metals in cereals collected from different wholesale markets of Dhaka City. One hundred and sixty cereal samples were collected and analyzed for determination of heavy metals. Heavy metals were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). A total of six heavy metals– lead, chromium, cadmium, mercury, arsenic and antimony were estimated. The average concentrations of heavy metals in cereals fall within the safe limit established by regulatory organizations except for Pb (152.4 μg/100g) and Hg (15.13 μg/100g) which exceeded the safe limits. BARI gom-26 was the highest source of Pb (304.1 μg/100g) whereas Haski-29 rice variety contained the highest amount of Hg (60.85 μg/100g). Though all the cereal varieties contained approximately same amount of Cr the naizer sail varieties contained huge amount of Cr (171.8 μg/100g). Among all the cereal samples miniket rice varieties contained the least amount of heavy metals. The concentration of Cr (63.24 μg/100g), Cd (5.54 μg/100g) and As (3.26 μg/100g) in all cereals were below the safe limits. The daily intake of heavy metals was determined using the total weight of cereals consumed each day multiplied by the concentrations of heavy metals in cereals. The daily intake was compared with provisional maximum tolerable daily intake set by different regulatory organizations. The daily intake of Cd (23.0 μg), Hg (63.0 μg) and as (13.6 μg) through cereals were below the risk level except for Pb (634.0 μg) and Cr (263.1 μg). As the main meal of average Bangladeshi people is boiled rice served with some sorts of vegetables, our findings indicate that the residents of Dhaka City are at risk from Pb and Cr contamination. Potential health risks from exposure to heavy metals in self-planted cereals need more attention.

Keywords: contamination, dietary exposure, heavy metals, human health, ICP-MS

Procedia PDF Downloads 419

Authors: Astghik R. Sukiasyan

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The semidental sweet maize of Armenian population under drought stress and pollution by some heavy metals (HMs) in sites along the river Debet was studied. Accordingly, the objective of this work was to investigate the antioxidant status of maize plant in order to identify simple and reliable criteria for assessing the degree of adaptation of plants to abiotic stress of drought and HMs. It was found that in the case of removal from the mainstream of the river, the antioxidant status of the plant varies. As parameters, the antioxidant status of the plant has been determined by the activity of malondialdehyde (MDA) and Ferric Reducing Ability of Plasma (FRAP), taking into account the characteristics of natural drought of this region. The possibility of using some indicators which characterized the antioxidant status of the plant was concluded. The criteria for assessing the extent of environmental pollution could be HMs. This fact can be used for the early diagnosis of diseases in the population who lives in these areas and uses corn as the main food.

Keywords: antioxidant status, maize corn, drought stress, heavy metal

Procedia PDF Downloads 239

Authors: Fiona Curran-Cournane

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Soil quality monitoring is a science-based soil management tool that assesses soil ecosystem health. A soil monitoring program in Auckland, New Zealand’s largest city, extends from 1995 to the present. The objective of this study was to firstly determine changes in soil parameters (basic soil properties and heavy metals) that were assessed from rural land in 1995-2000 and repeated in 2008-2012. The second objective was to determine differences in soil parameters across various land uses including native bush, rural (horticulture, pasture and plantation forestry) and urban land uses using soil data collected in more recent years (2009-2013). Across rural land, mean concentrations of Olsen P had significantly increased in the second sampling period and was identified as the indicator of most concern, followed by soil macroporosity, particularly for horticultural and pastoral land. Mean concentrations of Cd were also greatest for pastoral and horticultural land and a positive correlation existed between these two parameters, which highlights the importance of analysing basic soil parameters in conjunction with heavy metals. In contrast, mean concentrations of As, Cr, Pb, Ni and Zn were greatest for urban sites. Native bush sites had the lowest concentrations of heavy metals and were used to calculate a ‘pollution index’ (PI). The mean PI was classified as high (PI > 3) for Cd and Ni and moderate for Pb, Zn, Cr, Cu, As, and Hg, indicating high levels of heavy metal pollution across both rural and urban soils. From a land use perspective, the mean ‘integrated pollution index’ was highest for urban sites at 2.9 followed by pasture, horticulture and plantation forests at 2.7, 2.6, and 0.9, respectively. It is recommended that soil sampling continues over time because a longer spanning record will allow further identification of where soil problems exist and where resources need to be targeted in the future. Findings from this study will also inform policy and science direction in regional councils.

Keywords: heavy metals, pollution index, rural and urban land use, soil quality

Procedia PDF Downloads 353

Authors: G. Hosseini, A. Sadighzadeh, M. Rahimnejad, N. Hosseini, Z. Jamalzadeh

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Metal pollutants, especially heavy metals from anthropogenic sources such as metallurgical industries’ waste including mining, smelting, casting or production of nuclear fuel, including mining, concentrate production and uranium processing ends in the environment contamination (water and soil) and risk to human health around the facilities of this type of industrial activity. There are different methods that can be used to remove these contaminants from water and soil. These are very expensive and time-consuming. In this case, the people have been forced to leave the area and the decontamination is not done. For example, in the case of Chernobyl accident, an area of 30 km around the plant was emptied of human life. A very efficient and cost-effective method for decontamination of the soil and the water is phytoremediation. In this method, the plants preferentially native plants which are more adaptive to the regional climate are well used. In this study, three types of plants including Alfalfa, Sunflower and wheat were used to Barium decontamination. Alfalfa and Sunflower were not grown good enough in Saghand mine’s soil sample. This can be due to non-native origin of these plants. But, Wheat rise in Saghand Uranium Mine soil sample was satisfactory. In this study, we have investigated the effect of 4 types of acids inclusive nitric acid, oxalic acid, acetic acid and citric acid on the removal efficiency of Barium by Wheat. Our results indicate the increase of Barium absorption in the presence of citric acid in the soil. In this paper, we will present our research and laboratory results.

Keywords: phytoremediation, heavy metal, wheat, soil

Procedia PDF Downloads 300

Authors: Z. V. P. Murthy, Preeti Arunachalam, Sangeeta Balram

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Removal of metal ions from different wastewaters has become important due to their effects on living beings. Cadmium is one of the heavy metals found in different industrial wastewaters. There are many conventional methods available to remove heavy metals from wastewaters like adsorption, membrane separations, precipitation, electrolytic methods, etc. and all of them have their own advantages and disadvantages. The present work deals with the use of natural biosorbents (chitin and chitosan) to separate cadmium ions from aqueous solutions. The adsorption data were fitted with different isotherms and kinetics models. Amongst different adsorption isotherms used to fit the adsorption data, the Freundlich isotherm showed better fits for both the biosorbents. The kinetics data of adsorption of cadmium showed better fit with pseudo-second order model for both the biosorbents. Chitosan, the derivative from chitin, showed better performance than chitin. The separation results are encouraging.

Keywords: chitin, chitosan, cadmium, isotherm, kinetics

Procedia PDF Downloads 377

Authors: Saad M. Howladar

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Although, there are a little data on the use of littoral plants as heavy metals bioaccumulators over large areas of the wetlands environment. So, soil samples and biomass of the five plant species: Pluchea dioscroides, Pulicaria crispa, Lavandula pubescens, Tarchononthus comporatus and Argemone ochroleuca were collected from two different sites (basin and mouth) of four dams at Baha province, KSA. Nutrients and heavy metals were extracted from plant samples (leaves and stems) for analyzing elements (Na, K, Ca, P and N) and heavy metals (Pb, Cu and Ni). The soils of the mouth of the dam had the highest concentrations of all elements, while that of basin had the highest ones of most heavy metals except Pb. The soil elements in relation to the two sites arranged as: Ca > K > P > Na > N; and the heavy metals as: Cu > Ni > Pb. The present study indicated that Pluchea dioscroides had the highest values of most elements and heavy metals, while Lavandula pubescens had the lowest. In general, leaves attain the highest concentrations of all nutrients and heavy metals in most studied species as compared with stem. It was indicated that Pluchea dioscroides showed a high transfer factor for almost elements and heavy metals such as K, Na, Cu, Ni and Pb, while Pulicaria crispa showed the highest translocation factor of N, P, Ca-Na ratio and Cu. All studied species growing in the basin had almost the highest concentrations of elements and heavy metals as compared with that in the mouth of dam except K in Pluchea dioscroides, Tarchononthus comporatus and Argemone ochroleuca tissues. Otherwise tissues of Tarchononthus comporatus growing in the basin had the lowest concentrations of K and Ni, while that growing in the mouth had the highest of P and N.

Keywords: Baha Region, bioindicators, plant, pollution, dams, heavy metals

Procedia PDF Downloads 421

Authors: Aliya Kurbanova, Nurlan Akhmetov, Abilmansur Yeshmuratov, Yerzhigit Sugurbekov, Ramiz Zulkharnay, Gulzat Demeuova, Murat Baisariyev, Gulnar Sugurbekova

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Last decades crude oils have tended to become more challenge to process due to increasing amounts of sour and heavy crude oils. Some crude oils contain high vanadium and nickel content, for example Pavlodar LLP crude oil, which contains more than 23.09 g/t nickel and 58.59 g/t vanadium. In this study, we used two types of metal removing methods such as solvent extraction and electrochemical. The present research is conducted for comparative analysis of the deasphalting with organic solvents (cyclohexane, carbon tetrachloride, chloroform) and electrochemical method. Applying the cyclic voltametric analysis (CVA) and Inductively coupled plasma mass spectrometry (ICP MS), these mentioned types of metal extraction methods were compared in this paper. Maximum efficiency of deasphalting, with cyclohexane as the solvent, in Soxhlet extractor was 66.4% for nickel and 51.2% for vanadium content from crude oil. Percentage of Ni extraction reached maximum of approximately 55% by using the electrochemical method in electrolysis cell, which was developed for this research and consists of three sections: oil and protonating agent (EtOH) solution between two conducting membranes which divides it from two capsules of 10% sulfuric acid and two graphite electrodes which cover all three parts in electrical circuit. Ions of metals pass through membranes and remain in acid solutions. The best result was obtained in 60 minutes with ethanol to oil ratio 25% to 75% respectively, current fits into the range from 0.3A to 0.4A, voltage changed from 12.8V to 17.3V.

Keywords: demetallization, deasphalting, electrochemical removal, heavy metals, petroleum engineering, solvent extraction

Procedia PDF Downloads 279