Showing 11 results for Zinc
Mir Habibi A.r., Rabiei M., Agha Baba Zadeh R., Moztar Zadeh F., Hesaraki S.,
Volume 1, Issue 3 (9-2004)
Abstract
ZnS : Cu phosphors were prepared by using laboratory grade chemicals through coprecipitating Cu along with ZnS using H2S and thiourea. Photo- and electroluminescence studies indicate that these phosphors have better emission characteristics compared to the phosphors in which activator is externally added. Phosphors with luminescence at ~530nrn were prepared. The difference between the characteristic properties of the samples seems to be due to formation of nanoparticles during the preparation of the samples by different methods.
Karaminezhaad M., Maghsoudi A.a., Nozhati R., Sakhaei A.,
Volume 1, Issue 4 (12-2004)
Abstract
A large number of reinforced concrete structures subjected to chloride ions. Two basicapproaches for preventing corrosion of reinforcing steel embedded in concrete are: Increasing theconsolidation of concrete and using different coating on rebars. In present research steel rebarsare coated in different ways: a) 40 µm of zinc electroplated on steel rebar b) Zinc powder withepoxy paste (zinc rich). The rebars were placed in a macrocell design according to ASTM G109-92. Concrete operations were done with mixture designs of high and normal strength concrete.The results show corrosion decrease of zinc coated rebars.
M. Sheikhshab Bafghi, M. Karimi, M. Adeli,
Volume 10, Issue 4 (12-2013)
Abstract
In the present study, reduction of zinc oxide from the pellets made of steelmaking electric arc furnace dust has been investigated. Effects of such parameters as the type of carbon material (graphite, coke and charcoal) as well as time and temperature on the reduction reaction have been examined. The reduced (dimensionless) time method was applied to perform a kinetic analysis of the system. Experimental results showed that increasing the temperature in the range of 925-1150°C results in a remarkable increase in the reduction rate. It was also shown that the reduction process is controlled by chemical reaction. Meaningful difference in the activation energy values calculated for reduction with graphite (24.75 kcal/mol), coke (18.13 kcal/mol) and charcoal (11.52 kcal/mol) indicate the predominant role of chemical reaction (carbon gasification) in the overall reaction rate and its rate-controlling mechanism. Carbothermal reduction of pelletized EAF dust proved to be an efficient reduction method, so that above 90% reduction was achieved in about one hour at temperatures around 1100°C.
N. Ghanbarpourabdoli, Sh. Raygan, H. Abdizadeh,
Volume 13, Issue 4 (12-2016)
Abstract
In this study, the adsorption of hexavalent chromium and zinc ions from the solution is investigated by raw red mud and mechanical-chemical activated red mud along with the possibility of selective reclamation of these ions from the solution. The mechanical-chemical activation of red mud was done by employing high-energy milling and subsequent acid treatment with HNO3. Raw red mud (RRM) and mechanical-chemical activated red mud (MCARM) adsorbents were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscope (SEM), and Brunauer–Emmett–Teller (BET) methods. In order to determine the suitable adsorption conditions, effects of pH of the solution, amount of adsorption, temperature, and time of adsorption were investigated. It was found that the optimum pH for the adsorption of hexavalent chromium and zinc ions by MCARM adsorbent was 2 and 6, respectively. According to these pH values, MCARM had the ability to separately adsorb more than 95 and 79% of hexavalent chromium and zinc ions from the solution, respectively. Experimental results were in good agreement with Langmuir and Freundlich isotherms. By considering the kinetic models of adsorption, the kinetics of the adsorption of both ions followed the pseudo-second-order reaction model. It was also determined that almost 25.8 and 61.8% of the hexavalent chromium and zinc ions adsorbed in MCARM could be recovered
M. Ebrahimi, S. A. Seyyed Ebrahimi, S. M. Masoudpanah,
Volume 14, Issue 1 (3-2017)
Abstract
In this work, the effects of co-precipitation temperature and post calcination on the magnetic properties and photocatalytic activities of ZnFe2O4 nanoparticles were investigated. The structure, magnetic and optical properties of zinc ferrite nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetometry and UV–Vis spectrophotometry techniques. The XRD results showed that the coprecipitated as well as calcined nanoparticles are single phase with partially inverse spinel structures. The magnetization and band gap decreased with the increasing of co-precipitation temperature through the increasing of the crystallite size. However, the post calcination at 500 °C was more effective on the decreasing of magnetization and band gap. Furthermore, photocatalytic activity of zinc ferrite nanoparticles was studied by the degradation of methyl orange under UV-light irradiation. Compare with the coprecipitated ZnFe2O4 nanoparticles with 5% degradation of methyl orange after 5 h UV-light light radiation, the calcined ZnFe2O4 nanoparticles exhibited a better photocatalytic activity with 20% degradation.
Prabhakar Kuppahalli, Ramaiah Keshavamurthy, Padmanathan Sriram, Ahobal Narayana,
Volume 18, Issue 2 (6-2021)
Abstract
The present investigation aims to synthesize RB031, RB032 manganese bronze alloys equivalent to HTB1 and HTB2 alloys with additions of silicon and to characterize them with the help of Microstructure and Mechanical properties. The methodology involves melting of alloy’s in a 300kg Coreless medium frequency induction furnace, casting them in Permanent and Shell moulds with optimum values of Zinc equivalent and retaining their high mechanical properties. The study includes the development and mechanical property measurements of the alloys synthesized. Characterization has been carried out using Optical Microscopy and Scanning Electron Microscopy with EDAX analysis for investiagtion of compositional variations and inquisition of hardness measurement & tensile properties. It is concluded from this work that RB032 alloy cast in Permanent moulds has superior hardness and tensile properties compared to Shell moulds and far exceeds that of NAB (AB2) alloys processed under similar conditions. Further, this investigation includes grain refinement by suitable Heat treatment studies to combat Hot Tearing since the strength is adequate enough with RB032 exhibiting higher hardness than other two alloys.
Mohammed Ruhul Amin Bhuiyan, Hayati Mamur,
Volume 18, Issue 3 (9-2021)
Abstract
Carbon-based chemical substances persistence can contribute to adverse health impacts on human lives. It is essential to overcome for treatment purposes. The semiconducting metal oxide is Zinc Oxide (ZnO), which has excellent biocompatibility, good chemical stability, selectivity, sensitivity, non-toxicity, and fast electron transfer characteristics. The ZnO nanoparticles are more efficient compared to other metal oxide materials. Thus, the nanoparticles are in the present research situation to receive increasing attention due to their potential performance of the human body to feel comfortable. The nanoparticles become more promising for biomedical applications through the development of anticancer agents to recovery different types of malignant cells in the human body. The ZnO nanoparticles can be the future potential materials for biomedical applications. The purpose of this paper is to review the cost-effective approach to synthesize the ZnO nanoparticles. Moreover, these ideas can develop for synthesized ZnO biomaterial to perform easily up-scaled in biomedical applications.
Shadi Moshayedi, Hossein Sarpoolaky, Alireza Khavandi,
Volume 19, Issue 2 (6-2022)
Abstract
In this paper, chemically-crosslinked gelatin/chitosan hydrogels containg zinc oxide nanoparticles (ZNPs), were loaded with curcumin (CUR), and their microstructural features, physical properties, curcumin entrapment efficiency, and drug release kinetics were evaluated using scanning electron microscopy (SEM), the liquid displacement method, and UV–Vis spectroscopy. The in vitro kinetics of drug release was also studied using First-order, Korsmeyer-Peppas, Hixon-Crowell, and Higuchi kinetic models. The SEM micrographs confirmed the formation of highly porous structures possessing well-defined, interconnected pore geometries. A significant reduction in the average pore sizes of the drug-loaded hydrogels was observed with the addition of ZNPs and CUR to the bare hydrogels. High value of drug loading efficiency (~ 72 %) and maximum drug release of about 50 % were obtained for the drug-loaded scaffolds. It was found that curcumin was transported via the non-Fickian diffusion mechanism. It was also shown that the kinetics of curcumin release was best described in order by Hixon-Crowell, Higuchi, and Korsmeyer-Peppas models, demonstrating that drug release was controlled by diffusion, degradation, and swelling of the drug carrier. However, lower degree of fitting was observed with First-order kinetic model.
Farnaz Dehghani Firoozabadi, Ahmad Ramazani Saadatabadi, Azadeh Asefnejad,
Volume 19, Issue 2 (6-2022)
Abstract
Fabrication of fully optimized tissue-engineered materials in order to simulating the natural structure, and enhancing the biological properties of damaged tissue is one of the major challenges in biomedical engineering and regeneration medicine. Although polymeric based membranes have revealed noticeable advancements in bone regeneration, their mechanical stiffens, electrical conductivity and bioactivity need to be tolerated.
Therefore, the present study is designed to generate a multifunctional biomaterial based on polylactic acid (PLA)/ polycaprolactone (PCL)/hydroxyapatite (HA) nanocomposite containing zinc oxide (ZnO) and Graphene (Gr) nanoparticles employing solvent casting combined with die cast techniques for using as absorbable joint implants in bone tissue regeneration. The physical, chemical, mechanical and biological properties of the produced nanocomposite biomaterials were analyzed in vitro. A detailed experimental evaluation between the nanocomposite coatings was carried out to shed light on the effect of ZnO and Gr nanoparticles on the properties.
It was found that the nanocomposite contained 1% ZnO and 1% graphene with a Young's modulus of 1540.5 ± 169.426MPa and the pure sample had a Young's modulus of 1194.81±215.342MPa. The rate of elongation at break of the nanostructure contained 1% graphene was 5.1±0.816%. This value was 3.8±0.944% for the pure sample. The improvement in elongation at break is due to the presence of polycaprolactone in the polymer matrix. The optimal sample with 1% zinc oxide and 1% graphene had antibacterial properties more than other samples. Also, the survival rate of fibroblasts cell in the vicinity of the optimal matrix was significantly different from other samples.
The obtained results revealed that the incorporation of the nanoparticles improved physico-chemical features and mechanical strength with enhanced biological properties and its anti-bacterial performance makes this material a promising candidate for further bone regeneration studies.
Saba Payrazm, Saeid Baghshahi, Zahra Sadeghian, Amirtaymour Aliabadizadeh,
Volume 19, Issue 3 (9-2022)
Abstract
In this research, zinc oxide quantum dots and graphene nanocomposites were synthesized via two different methods; In the first (direct) method, ZnO-graphene Nanocomposites were made mixing the synthesized zinc oxide and graphene. In the second (indirect) method, zinc nitrate, graphene, and sodium hydroxide were used to made ZnO-graphene Nanocomposites. XRD, FTIR and Raman spectroscopy analyses were used for phase and structural evaluations. The morphology of the nanocomposites w::as char::acterized by SEM. The specific surface area and porosity of the samples were characterized by BET analysis. The optical properties of the samples were investigated by photoluminescence and ultraviolet-visible spectroscopy analyses. Results showed that using graphene, increased the photoluminescence property and shifted the photoluminescence spectrum of the composites towards the visible light spectrum. The photoluminescence of the synthesized graphene-zinc oxide composite, in the visible light region, was closer to white light than that of pure zinc oxide. According to the results of BET test, the nanocomposite synthesized by direct method had a higher surface area (25.7 m2.g-1) and a higher porosity (0.32 cm3.g-1) than the nanocomposite synthesized by the indirect method with a specific surface area of (16.5 m2.g-1) and a porosity of 0.23 cm3.g-1).
Rakhesh V, Sreedev P, Ananthakrishnan A,
Volume 21, Issue 2 (6-2024)
Abstract
Organic and Perovskite solar cells have attracted a lot of attention recently since they can be used with flexible substrates and have lower manufacturing costs. The configuration and materials employed in their construction, including the Electron Transport Layer (ETL), active layer, electrode contact, and hole transport layer greatly influence the stability and performance of these solar cells. This research focuses on the simulation of solar cells, specifically utilizing zinc oxide (ZnO) as the electron transport layer. A 0.1 molar ZnO thin film was prepared from Zinc acetate salt and was deposited on a glass substrate using the cost effective Successive Ionic Layer Adsorption and Reaction (SILAR) method. In-depth investigations were carried out on several factors, including structural, surface, optical and numerical analysis. The obtained parameters were utilized in the General-Purpose Photovoltaic Device Model (GPVDM) software to perform numerical simulations of the organic solar cell and Perovskite solar cell. Both Organic solar cells and Perovskite solar cells were designed numerically and through careful observations, electrical parameters like Open circuit Voltage (Voc), Short circuit current (Jsc), Fill Factor (FF), and Power Conversion Efficiency (PCE) were identified. The studies indicate the promising performance of simulated solar cells with SILAR-synthesized ZnO thin film as the ETL.
