Search results for: Zinc oxide nanopowder

Authors: Saeed Rezaei-Zarchi

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Platinum oxide nanoparticles were prepared by a simple hydrothermal route and chemical reduction using carbohydrates (Fructose and sucrose) as the reducing and stabilizing agents. The crystallite size of these nanoparticles was evaluated from X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and was found to be 10 nm as shown in figure 1, which is the demonstration of EM bright field and transmission electron microscopy. The effect of carbohydrates on the morphology of the nanoparticles was studied using TEM (Figure 1). The nanoparticles (100 μg/ml) were administered to the Pseudomonas Stutzeri and Lactobacillus cultures and the incubation was done at 35 oC for 24 hours. The nanocomposites exhibited interesting inhibitory as well as bactericidal activity against P. Stutzeri and and Lactobacillus species. Incorporation of nanoparticles also increased the thermal stability of the carbohydrates.

Keywords: Platinum oxide, P. Stutzeri, Lactobacillus, bactericidal effect.

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Authors: Indah Kurniawaty, Yoki Yulizar, Haryo Satrya Oktaviano, Adam Kusuma Rianto

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Magnesium oxide nanoparticles (MgO NP) were successfully synthesized in this study using a one-pot green synthesis mediated by Calliandra calothyrsus leaf extract (CLE). CLE was prepared by maceration of the leaf using methanol with a ratio of 1:5 for 7 days. Secondary metabolites in CLE, such as alkaloids and flavonoids, served as a weak base provider and capping agent in the formation of MgO NP. CLE Fourier Transform Infra-Red (FTIR) spectra peak at 3255 cm-1, 1600 cm-1, 1384 cm-1, 1205 cm-1, 1041 cm-1, and 667 cm-1 showing the presence of vibrations O-H stretching, N-H bending, C-C stretching, C-N stretching and N-H wagging. During the experiment, different CLE volumes and calcined temperatures were used, resulting in a variety of structures. Energy Dispersive X-ray Spectrometer (EDS) and FTIR were used to characterize metal oxide particles. MgO diffraction patterns at 2θ of 36.9°; 42.9°; 62.2°; 74.6°; and 78.5° can be assigned to crystal planes (111), (200), (220), (311), and (222), respectively. Scanning Electron Microscopy (SEM) was used to characterize the surface morphology. The morphology ranged from sphere to flower-like resulting in crystallite sizes of 28 nm, 23 nm, 12 nm, and 9 nm.

Keywords: Calliandra calothyrsus, green-synthesis, magnesium oxide, nanoparticle.

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Authors: Shibesh Dutta, Sivaramakrishnan R., Sundar Gopalan, Balakrishnan Shankar

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MOSCAPs of various combinations of Hafnium oxide and Titanium oxide of varying thickness with Aluminum as gate electrode have been fabricated and electrically characterized. The effects of voltage stress on the I-V characteristics for prolonged time durations have been studied and compared. Results showed hard breakdown and negligible degradation of reliability under stress.

Keywords: breakdown, MOSCAP, voltage stress.

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Authors: K. K. Saju, A. R. Reghuraj

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High reflectance of surgical instruments under bright light hinders the visual clarity during laparoscopic surgical procedures leading to loss of precision and device control and creates strain and undesired difficulties to surgeons. Majority of the surgical instruments are made of surgical grade steel. Instruments with a non reflective surface can enhance the visual clarity during precision surgeries. A conversion coating of black oxide has been successfully developed 410 grade surgical stainless steel .The characteristics of the developed coating suggests the application of this technique for developing 410 grade surgical instruments with minimal reflectance.

Keywords: Conversion coatings, 410 stainless steel, black oxide, reflectance.

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Authors: Chiu-Wen Chen, Chih-Feng Chen, Cheng-Di Dong

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The distribution, enrichment, and accumulation of zinc (Zn) in the sediments of Kaohsiung Ocean Disposal Site (KODS), Taiwan were investigated. Sediment samples from two outer disposal site stations and nine disposed stations in the KODS were collected per quarterly in 2009 and characterized for Zn, aluminum, organic matter, and grain size. Results showed that the mean Zn concentrations varied from 48 mg/kg to 456 mg/kg. Results from the enrichment factor (EF) and geo-accumulation index (Igeo) analyses imply that the sediments collected from the KODS can be characterized between moderate and moderately severe degree enrichment and between none and none to medium accumulation of Zn, respectively. However, results of potential ecological risk index indicate that the sediment has low ecological potential risk. The EF, Igeo, and Zn concentrations at the disposed stations were slightly higher than those at outer disposal site. This indicated that the disposed area centers may be subjected to the disposal impaction of harbor dredged sediments.

Keywords: ocean dispose; zinc; enrichment factor; potential ecological risk index.

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Authors: H. Fazlinejad, A. Halvaee

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In this study, characteristics of ATIG welds using ZnO flux on aluminum was investigated and compared with TIG welds. Autogenously AC-ATIG bead on plate welding was applied on Al1050 plate with a coating of ZnO as the flux. Different levels of welding current and flux layer thickness was considered to study the effect of heat input and flux quantity on ATIG welds and was compared with those of TIG welds. Geometrical investigation of the weld cross sections revealed that penetration depth of the ATIG welds with ZnO flux, was increased up to 2 times in some samples compared to the TIG welds. Optical metallographic and Scanning Electron Microscopy (SEM) observations revealed similar microstructures in TIG and ATIG welds. Composition of the ATIG welds slag was also analyzed using X-ray diffraction. In both TIG and ATIG samples, the lowest values of microhardness were observed in the HAZ.

Keywords: ATIG, active flux, weld penetration, Al 1050, ZnO.

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Authors: Juliana V. Pereira, Adriana S. M. Batista, Jefferson P. Nascimento, Clascídia A. Furtado, Luiz O. Faria

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Exposure to ionizing radiation has been found to induce changes in poly(vinylidene fluoride) (PVDF) homopolymers. The high dose gamma irradiation process induces the formation of C=C and C=O bonds in its [CH₂-CF₂]_n main chain. The irradiation also provokes crosslinking and chain scission. All these radio-induced defects lead to changes in the PVDF crystalline structure. As a consequence, it is common to observe a decrease in the melting temperature (T_M) and melting latent heat (L_M) and some changes in its ferroelectric features. We have investigated the possibility of preparing nanocomposites of PVDF with graphene oxide (GO) through the radio-induction of molecular bonds. In this work, we discuss how the gamma radiation interacts with the nanocomposite crystalline structure.

Keywords: Gamma irradiation, grapheme oxide, nanocomposites, PVDF.

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Authors: Zhiping Wu, Meiqin Chen, Haikuan Yang, Yunchu Hu

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Fire disaster is the major factor to endanger the public and environmental safety. People lost their life during fire disaster mainly be attributed to the dense smoke and toxic gas under combustion, which hinder the escape of people and the rescue of firefighters under fire disaster. The smoke suppression effect of several transitional metals oxide on the epoxy resin treated with intumescent flame retardant and titanate couple agent (EP/IFR/Titanate) system have been investigated. The results showed manganese dioxide has great effect on reducing the smoke density rate (SDR) of EP/IFR/Titanate system; however it has little effect to reduce the maximum smoke density (MSD) of EP/IFR/Titanate system. Copper oxide can decrease the maximum smoke density (MSD) and smoke density rate of EP/IFR/Titanate system substantially. The MSD and SDR of EP/IFR/Titanate system can reduce 20.3% and 39.1% respectively when 2% of copper oxide is introduced.

Keywords: copper oxide, epoxy resin, intumescent flameretardant, smoke suppression.

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Authors: V. Endo, A.G. Silva Sobrinho, N.L.L. Lima, G.M. Manzi, L.G.A. Cirne, V.T. Santana, F.A. Almeida

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This study aimed to evaluate the muscularity and tissue composition of 24 legs of Ile de France lambs. They were fed with diets containing “in nature" or hydrolyzed sugarcane with 0.6% of calcium oxide in aerobic and anaerobic environments. Animals entered the trial at 15 and were slaughtered at 32 kg of body weight. The leg tissue composition, as well as muscularity (0.47), muscle:bone (6.66) and muscle:fat (4.25) were not affected (P>0.05) by treatments. The proportions found were: 67.62% for muscle, 17.52% for bone and 10.15% for fat. In relation to lambs fed with “in nature" sugarcane, hydrolyzed sugarcane with calcium oxide in aerobic and anaerobic environments did not affect muscularity and leg tissue composition of lambs.

Keywords: calcium oxide, feedlot, Saccharum officinarum

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Authors: C. Rattanakawin, S. Vasailor

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Acid leaching of flotation concentrate of oxide copper ore containing mainly of malachite was performed in a standard agitation tank with various parameters. The effects of solid to liquid ratio, sulfuric acid concentration, agitation speed, leaching temperature and time were examined to get proper conditions. The best conditions are 1:8 solid to liquid ratio, 10% concentration by weight, 250 rev/min, 30 ^oC and 5-min leaching time in respect. About 20% Cu grade assayed by atomic absorption technique with 98% copper recovery was obtained from these combined optimum conditions. Dissolution kinetics of the concentrate was approximated as a logarithmic function. As a result, the first-order reaction rate is suggested from this leaching study.

Keywords: Agitation leaching, dissolution kinetics, flotation concentrate, oxide copper ore, sulfuric acid.

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Authors: T.K. Tan, P.S. Khiew, W.S. Chiu, S.Radiman, R.Abd-Shukor, N.M. Huang, H.N. Lim

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In our recent study, we have used ZnO nanoparticles assisted with UV light irradiation to investigate the photocatalytic degradation of Phenol Red (PR). The ZnO photocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area analysis (BET) and UVvisible spectroscopy. X-ray diffractometry result for the ZnO nanoparticles exhibit normal crystalline phase features. All observed peaks can be indexed to the pure hexagonal wurtzite crystal structures, with the space group of P63mc. There are no other impurities in the diffraction peak. In addition, TEM measurement shows that most of the nanoparticles are rod-like and spherical in shape and fairly monodispersed. A significant degradation of the PR was observed when the catalyst was added into the solution even without the UV light exposure. In addition, the photodegradation increases with the photocatalyst loading. The surface area of the ZnO nanomaterials from the BET measurement was 11.9 m2/g. Besides the photocatalyst loading, the effect of some parameters on the photodegradation efficiency such as initial PR concentration and pH were also studied.

Keywords: Nanostructures, phenol red, zinc oxide, heterogeneous photocatalyst.

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Authors: Ek Ngoy, A F Mulaba-Bafubiandi

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Cobalt was acid nitric leached from a mixed cobaltcopper oxide with variable acid concentration. Resulting experimental data were used to analyze effects of increase in acid concentration, based on a shrinking core model of the process. The mathematical simulation demonstrated that the time rate of the dissolution mechanism is an increasing function of acid concentration. It was also shown that the magnitude of the acid concentration effect is time dependent and the increase in acid concentration is more effective at earlier stage of the dissolution than at later stage. The remaining process parameters are comprehensively affected by acid concentration and their interaction is synergetic.

Keywords: Acid effect, Cobalt, Cobalt-copper oxide, Leaching, Simulation

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Authors: Maryam Afsharpour, Saleh Imani, Shahrzad Abdolmohammadi

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We investigate the ZnO role in the inherent protection of old manuscripts to protect them against environmental damaging effect of ultraviolet radiation, pollutant gasses, mold and bacteria. In this study a cellulosic nanocomposite of ZnO were used as protective coating on the surface of paper fibers. This layered nanocomposite can act as a consolidate materials too. Furthermore, to determine how well paper works screen objects from the damaging effects, two accelerated aging mechanisms due to light and heat are discussed. Results show good stability of papers with nanocomposite coating. Also, a good light stability was shown in the colored paper that treated with this nanocomposite. Furthermore, to demonstrate the degree of antifungal and antibacterial properties of coated papers, papers was treated with four common molds and bacteria and the good preventive effects of coated paper against molds and bacteria are described.

Keywords: Enviromental effects, Manuscript, Nanocomposite, Zinc oxide.

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Authors: Sanaz Seraj, Shohre Rouhani

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Recently, graphene has gained much attention because of its unique optical, mechanical, electrical, and thermal properties. Graphene has been used as a key material in the technological applications in various areas such as sensors, drug delivery, super capacitors, transparent conductor, and solar cell. It has a superior quenching efficiency for various fluorophores. Based on these unique properties, the optical sensors with graphene materials as the energy acceptors have demonstrated great success in recent years. During quenching, the emission of a fluorophore is perturbed by a quencher which can be a substrate or biomolecule, and due to this phenomenon, fluorophore-quencher has been used for selective detection of target molecules. Among fluorescence dyes, 1,8-naphthalimide is well known for its typical intramolecular charge transfer (ICT) and photo-induced charge transfer (PET) fluorophore, strong absorption and emission in the visible region, high photo stability, and large Stokes shift. Derivatives of 1,8-naphthalimides have found applications in some areas, especially fluorescence sensors. Herein, the fluorescence quenching of graphene oxide has been carried out on a naphthalimide dye as a fluorescent probe model. The quenching ability of graphene oxide on naphthalimide dye was studied by UV-VIS and fluorescence spectroscopy. This study showed that graphene is an efficient quencher for fluorescent dyes. Therefore, it can be used as a suitable candidate sensing platform. To the best of our knowledge, studies on the quenching and absorption of naphthalimide dyes by graphene oxide are rare.

Keywords: Fluorescence, graphene oxide, naphthalimide dye, quenching.

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Authors: U K Chakrabarti, Jigisha Parikh

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Hazardous Material transportation by road is coupled with inherent risk of accidents causing loss of lives, grievous injuries, property losses and environmental damages. The most common type of hazmat road accident happens to be the releases (78%) of hazardous substances, followed by fires (28%), explosions (14%) and vapour/ gas clouds (6 %.). The paper is discussing initially the probable 'Impact Zones' likely to be caused by one flammable (LPG) and one toxic (ethylene oxide) chemicals being transported through a sizable segment of a State Highway connecting three notified Industrial zones in Surat district in Western India housing 26 MAH industrial units. Three 'hotspots' were identified along the highway segment depending on the particular chemical traffic and the population distribution within 500 meters on either sides. The thermal radiation and explosion overpressure have been calculated for LPG / Ethylene Oxide BLEVE scenarios along with toxic release scenario for ethylene oxide. Besides, the dispersion calculations for ethylene oxide toxic release have been made for each 'hotspot' location and the impact zones have been mapped for the LOC concentrations. Subsequently, the maximum Initial Isolation and the protective zones were calculated based on ERPG-3 and ERPG-2 values of ethylene oxide respectively which are estimated taking the worst case scenario under worst weather conditions. The data analysis will be helpful to the local administration in capacity building with respect to rescue / evacuation and medical preparedness and quantitative inputs to augment the District Offsite Emergency Plan document.

Keywords: Hotspot, Ethylene Oxide, LPG, MAH (MajorAccident Hazard).

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Authors: Abir Yahya, Hacen Dhahri, Khalifa Slimi

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The present paper deals with a numerical simulation of temperature field inside a solid oxide fuel cell (SOFC) components. The temperature distribution is investigated using a co-flow planar SOFC comprising the air and fuel channel and two-ceramic electrodes, anode and cathode, separated by a dense ceramic electrolyte. The Lattice Boltzmann method (LBM) is used for the numerical simulation of the physical problem. The effects of inlet temperature, anode thermal conductivity and current density on temperature distribution are discussed. It was found that temperature distribution is very sensitive to the inlet temperature and the current density.

Keywords: Solid oxide fuel cell, Heat sources, temperature, Lattice Boltzmann method.

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Authors: André M. Ornelas, Lise P. Labéjof, Ligia V. Lage dos Santos, Jackson A. Santos

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The excessive use of agricultural pesticides and the resulting contamination of food and beds of rivers have been a recurring problem nowadays. Some of these substances can cause changes in endocrine balance and impair reproductive function of human and animal population. In the present study, we evaluated the possible effects of the fungicide cuprous copper oxide Sandoz® on pregnant Wistar rats. They received a daily oral administration of 103 or 3.103 mg/kg of the fungicide from the 6th to the 15th day of gestation. On day 21 of gestation, the maternal and fetal toxicity parameters and indices were determined. The administration of cuprous oxide (Copper Sandoz) in Wistar rats, the period of organogenesis, revealed no evidence of maternal toxicity or embryo at the studied doses.

Keywords: Reproductive toxicity, endocrine disrupter, cupper Sandoz®, rodent

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Authors: M. Mohammadi

Abstract:

In order to evaluate the effect of phosphate and Zn bio-fertilizers on the yield, phytic acid (PA), Zn concentration and PA/Zn molar ratio in bean, a field experiment was carried out for two years. The treatments included two cultivars of bean (Talash and Sadri), four levels of P (P₀, P₁: 100 kg ha^-1 triple super phosphate (TSP), P2: 50 kg ha^-1 TSP + phosphate bio-fertilizer, P₃: phosphate bio-fertilizer), three levels of Zn (Zn₀, Zn₁: 50 kg ha^-1 ZnSO4, Zn₂: Zn bio-fertilizer). Phosphate bio-fertilizer consisted of inoculum of mycorrhizal fungus and Azotobacter and Zn bio-fertilizer consisted of Pseudomonas bacteria. The results revealed that there was significant difference between yield and Zn concentration between years. The effect of cultivar was significant on studied parameters. The lowest content of PA and PA/Zn were obtained from Talash. P treatment caused to significant difference on parameters in which P₂ caused to increase yield, P and Zn concentration, and decrease PA and PA/Zn by 21.8%, 38.2%, 33.4%, 17.4% and 38.6% respectively. Zn treatment caused to significant difference on studied parameters. The maximum number of parameters were obtained from Zn₁ and Zn₂. The higher Zn concentration led to lower content of PA and PA/Zn. Using of P and Zn bio–fertilizers were caused to increasing nutrient uptake, improving growth condition and reducing PA and PA/Zn molar ratio.

Keywords: Mycorrhizae, phosphorus, pseudomonas, zinc.

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Authors: M. Nabeel Rashin, J. Hemalatha

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Novel Coconut oil nanofluids of various concentrations have been prepared through ultrasonically assisted sol-gel method. The structural and morphological properties of the copper oxide nanoparticle have been analyzed with respectively and it revealed the monoclinic end-centered structure of crystallite and shuttle like flake morphology of agglomerates. Ultrasonic studies have been made for the nanofluids at different temperatures. The molecular interactions responsible for the changes in acoustical parameter with respect to concentration and temperature are discussed.

Keywords: Cutting Fluid, Molecular Interaction, Nanofluids, Ultrasonic

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Authors: P. Chockalingam, C. K. Kok, T. R. Vijayaram

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A study on grindability of chopped strand mat glass fiber reinforced polymer laminates (CSM GFRP) have been carried out to evaluate the significant parameters on wheel performance. Performance of Aluminum oxide and c-BN wheels during grinding of CSM GFRP laminate was evaluated in terms of grinding force and surface roughness during grinding. The cubic Boron Nitride wheel experiences higher tangential grinding forces components and lower normal force component than Aluminum oxide grinding wheels. In case of surface finish, Aluminum oxide grinding wheels outdo the cubic Boron Nitride grinding wheels.

Keywords: Grinding, glass fiber reinforced polymer laminates, grinding force, surface finish.

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Authors: Megha Rao, Søren H. Jensen, Xiufu Sun, Anke Hagen, Mogens B. Mogensen

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Solid oxide electrolysis cells have an immense potential in converting CO₂ and H₂O into syngas during co-electrolysis operation. The produced syngas can be further converted into hydrocarbons. This kind of technology is called power-to-gas or power-to-liquid. To produce hydrocarbons via this route, durability of the cells is still a challenge, which needs to be further investigated in order to improve the cells. In this work, various nickel-yttria stabilized zirconia (Ni-YSZ) fuel electrode supported or YSZ electrolyte supported cells, cerium gadolinium oxide (CGO) barrier layer, and an oxygen electrode are investigated for durability under co-electrolysis conditions in both galvanostatic and potentiostatic conditions. While changing the gas on the oxygen electrode, keeping the fuel electrode gas composition constant, a change in the gas concentration arc was observed by impedance spectroscopy. Measurements of open circuit potential revealed the presence of leaks in the setup. It is speculated that the change in concentration impedance may be related to the leaks. Furthermore, the cells were also tested under pressurized conditions to find an inter-play between the leak rate and the pressure. A mathematical modeling together with electrochemical and microscopy analysis is presented.

Keywords: Co-electrolysis, solid oxide electrolysis cells, leaks, durability, gas concentration.

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Authors: M. S. Kilic, S. Korkut, B. Hazer

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Newly synthesized Polypropylene-g-Polyethylene glycol polymer was first time used for a compartment-less enzymatic fuel cell. Working electrodes based on Polypropylene-g-Polyethylene glycol were operated as unmediated and mediated system (with ferrocene and gold/cobalt oxide nanoparticles). Glucose oxidase and bilirubin oxidase was selected as anodic and cathodic enzyme, respectively. Glucose was used as fuel in a single-compartment and membrane-less cell. Maximum power density was obtained as 0.65 nW cm-2, 65 nW cm-2 and 23500 nW cm-2 from the unmediated, ferrocene and gold/cobalt oxide modified polymeric film, respectively. Power density was calculated to be ~16000 nW cm-2 for undiluted wastewater sample with gold/cobalt oxide nanoparticles including system.

Keywords: Bilirubin oxidase, Enzymatic fuel cell, Glucose oxidase, Nanoparticles.

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Authors: Vipin Kumar Jain, Praveen Kumar, Y.K. Vijay

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ZnO-SnO2 i.e. Zinc-Tin-Oxide (ZTO) thin films were deposited on glass substrate with varying concentrations (ZnO:SnO2 - 100:0, 90:10, 70:30 and 50:50 wt.%) at room temperature by flash evaporation technique. These deposited ZTO film were annealed at 450 0C in vacuum. These films were characterized to study the effect of annealing on the structural, electrical, and optical properties. Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) images manifest the surface morphology of these ZTO thin films. The apparent growth of surface features revealed the formation of nanostructure ZTO thin films. The small value of surface roughness (root mean square RRMS) ensures the usefulness in optical coatings. The sheet resistance was also found to be decreased for both types of films with increasing concentration of SnO2. The optical transmittance found to be decreased however blue shift has been observed after annealing.

Keywords: ZTO thin film, AFM, SEM, Optical transmittance, Sheet resistance.

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Authors: Maryamossadat Bozorgtabar, Mohammadreza Rahimipour, Mehdi Salehi, Mohammadreza Jafarpour

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Titanium dioxide coatings were deposited by utilizing atmospheric plasma spraying (APS) system. The agglomerated nanopowder and different spraying parameters were used to determine their influences on the microstructure surface feature and photoabsorption of the coatings. The microstructure of as-sprayed TiO2 coatings were characterized by scanning electron microscope (SEM). Surface characteristics were investigated by Fourier Transform Infrared (FT-IR). The photo absorption was determined by UV-VIS spectrophotometer. It is found that the spray parameters have an influence on the microstructure, surface feature and photo-absorption of the TiO2 coatings.

Keywords: APS, TiO2, Nanostructured Coating, Photoabsorption

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Authors: Ebeed A. Saleh, Kadry M. Sadek, Safaa H. Ghorbal

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Due to the determination of the pollution status of fresh resources in the Egyptian territorial waters is very important for public health; this study was carried out to reveal the levels of heavy metals in the shellfish and their environment and its relation to the highly developed industrial activities in those areas. A total of 100 shellfish samples from the Rosetta, Edku, El-Maadiya, Abo-Kir and El-Max coasts [10 crustaceans (shrimp) and 10 mollusks (oysters)] were randomly collected from each coast. Additionally, 10 samples from both the water and the sediment were collected from each coast. Each collected sample was analyzed for cadmium, chromium, copper, lead and zinc residues using a Perkin Elmer atomic absorption spectrophotometer (AAS). The results showed that the levels of heavy metals were higher in the water and sediment from Abo-Kir. The heavy metal levels decreased successively for the Rosetta, Edku, El-Maadiya, and El-Max coasts, and the concentrations of heavy metals, except copper and zinc, in shellfish exhibited the same pattern. For the concentration of heavy metals in shellfish tissue, the highest was zinc and the concentrations decreased successively for copper, lead, chromium and cadmium for all coasts, except the Abo-Kir coast, where the chromium level was highest and the other metals decreased successively for zinc, copper, lead and cadmium. In Rosetta, chromium was higher only in the mollusks, while the level of this metal was lower in the crustaceans; this trend was observed at the Edku, El-Maadiya and El-Max coasts as well. Herein, we discuss the importance of such contamination for public health and the sources of shellfish contamination with heavy metals. We suggest measures to minimize and prevent these pollutants in the aquatic environment and, furthermore, how to protect humans from excessive intake.

Keywords: Atomic absorption, heavy metals, sediment, shellfish, water.

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Authors: Mu-Jen Young, Cheng-Yen Wu, Wen-Yuan Hsieh

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Iron oxide nanoparticle was synthesized by reactive-precipitation method followed by high speed centrifuge and phase transfer in order to stabilized nanoparticles in the solvent. Particle size of SPIO was 8.2 nm by SEM, and the hydraulic radius was 17.5 nm by dynamic light scattering method. Coercivity and saturated magnetism were determined by VSM (vibrating sample magnetometer), coercivity of nanoparticle was lower than 10 Hc, and the saturated magnetism was higher than 65 emu/g. Stabilized SPIO was then transferred to aqueous phase by reacted with excess amount of poly (ethylene glycol) (PEG) silane. After filtration and dialysis, the SPIO T2 contrast agent was ready to use. The hydraulic radius of final product was about 70~100 nm, the relaxation rates R2 (1/T2) measured by magnetic resonance imaging (MRI) was larger than 200(sec-1).

Keywords: Contrast Agent, Iron Oxide Nanoparticle, Magnetic Resonance Imaging, Nanoparticle Stabilization

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Authors: Rong Liu, Kuiying Chen, Ju Chen, Jingrong Zhao, Ming Liang

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This article presents modeling studies of NiAl alloy under solid-particle erosion and liquid-drop erosion. In the solid-particle erosion simulation, attention is paid to the oxide scale thickness variation on the alloy in high-temperature erosion environments. The erosion damage is assumed to be deformation wear and cutting wear mechanisms, incorporating the influence of the oxide scale on the eroded surface; thus the instantaneous oxide thickness is the result of synergetic effect of erosion and oxidation. For liquid-drop erosion, special interest is in investigating the effects of drop velocity and drop size on the damage of the target surface. The models of impact stress wave, mean depth of penetration, and maximum depth of erosion rate (Max DER) are employed to develop various maps for NiAl alloy, including target thickness vs. drop size (diameter), rate of mean depth of penetration (MDRP) vs. drop impact velocity, and damage threshold velocity (DTV) vs. drop size.

Keywords: Liquid-drop erosion, NiAl alloy, oxide scale thickness, solid-particle erosion.

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Authors: Gouda K. Helal, Marwa I. Shabayek, Heba A. El-Ramly, Heba A. Awida

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The adverse effects of Clindamycin (Clind.) / Ibuprofen (Ibu.) combination on liver, kidney, blood elements and the significances of antioxidants (N-acetylcysteine and Zinc) against these effects were evaluated. The study includes: Group I; control n=30, Group II; patients on Clind.300mg/Ibu.400mg twice daily for a week n=30, Group III; patients on Clind.300mg/Ibu.400mg+Nacetylcysteine 200mg twice daily for a week n=15 and Group IV; patients on Clind.300mg/Ibu.400mg+Zinc50mg twice daily for a week n=15. Serum malondialdehyde (MDA), alanine transferase (ALT), aspartate transferase (AST), γ glutamyl transferase (GGT), creatinine, blood urea nitrogen (BUN) were measured. Applying one way ANOVA followed by Tuckey Kramer post test, Group II showed significant increase in ALT, AST, GGT, BUN and decrease in Hb, RBCs, platelets than Group I. Group III showed significant decrease in ALT, AST, GGT, BUN than Group II. Moreover, Group IV showed significant decrease in ALT, AST, GGT and increase in Hb, RBCs, and platelets than Group II. Conclusively, Adding Zinc or Nacetylcysteine buffer the oxidative stress and improve the therapeutic outcome of Clindamycin/Ibuprofen combination.

Keywords: Clindamycin, Ibuprofen, Adverse effects, Antioxidant, Zinc, N-acetylcysteine.

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Authors: Junya Takenami, Md. Azhar Uddin, Eiji Sasaoka, Yasushi Shioya, Tsuneyoshi Takase

Abstract:

In this study, we sought to investigate the mercury removal efficiency of manganese oxides from natural gas. The fundamental studies on mercury removal with manganese oxides sorbents were carried out in a laboratory scale fixed bed reactor at 30 °C with a mixture of methane (20%) and nitrogen gas laden with 4.8 ppb of elemental mercury. Manganese oxides with varying surface area and crystalline phase were prepared by conventional precipitation method in this study. The effects of surface area, crystallinity and other metal oxides on mercury removal efficiency were investigated. Effect of Ag impregnation on mercury removal efficiency was also investigated. Ag supported on metal oxide such titania and zirconia as reference materials were also used in this study for comparison. The characteristics of mercury removal reaction with manganese oxide was investigated using a temperature programmed desorption (TPD) technique. Manganese oxides showed very high Hg removal activity (about 73-93% Hg removal) for first time use. Surface area of the manganese oxide samples decreased after heat-treatment and resulted in complete loss of Hg removal ability for repeated use after Hg desorption in the case of amorphous MnO2, and 75% loss of the initial Hg removal activity for the crystalline MnO2. Mercury desorption efficiency of crystalline MnO2 was very low (37%) for first time use and high (98%) after second time use. Residual potassium content in MnO2 may have some effect on the thermal stability of the adsorbed Hg species. Desorption of Hg from manganese oxides occurs at much higher temperatures (with a peak at 400 °C) than Ag/TiO2 or Ag/ZrO2. Mercury may be captured on manganese oxides in the form of mercury manganese oxide.

Keywords: Mercury removal, Metal and metal oxide sorbents, Methane, Natural gas.

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Authors: H. Y. Jung, Ju H. Park, S. M. Lee

Abstract:

Sampled-data controller is presented for solid oxide fuel cell systems which is expressed by a sector bounded nonlinear model. The proposed control law is obtained by solving a convex problem satisfying several linear matrix inequalities. Simulation results are given to show the effectiveness of the proposed design method.

Keywords: Sampled-data control, Sector bound, Solid oxide fuel cell, Time-delay.

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