Journal of Nanoparticles The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Width of Nucleation Region of Si Nanocrystal Grains Prepared by Pulsed Laser Ablation with Different Laser Fluence Mon, 23 Mar 2015 11:21:36 +0000 Si nanocrystal grains were prepared by pulsed laser ablation with different laser fluence in Ar gas of 10 Pa at room temperature. The as-formed grains in the space deposited on the substrates and distributed in a certain range apart from target. According to the depositing position and radius of grains, the nucleation locations of grains in the space were roughly calculated. The results indicated that the width of nucleation region broadened with increasing of ion densities diagnosed by Langmuir probe, which increased with laser fluence from 2 J/cm2 to 6 J/cm2; that is, width of nucleation region broadened with addition of laser fluence. At the same time, the width broadened with the terminal formation position moving backward and the initial formation position of grains moving toward ablated spot. The experimental results were explained reasonably by nucleation thermokinetic theory. Zechao Deng, Xuexia Pang, Xuecheng Ding, Lizhi Chu, and Yinglong Wang Copyright © 2015 Zechao Deng et al. All rights reserved. Carbon Dot Based Sensing of Dopamine and Ascorbic Acid Mon, 29 Dec 2014 09:07:27 +0000 We demonstrate carbon dot based sensor of catecholamine, namely, dopamine and ascorbic acid. Carbon dots (CDs) were prepared from a green source: commercially available Assam tea. The carbon dots prepared from tea had particle sizes of ∼0.8 nm and are fluorescent. Fluorescence of the carbon dots was found to be quenched in the presence of dopamine and ascorbic acid with greater sensitivity for dopamine. The minimum detectable limits were determined to be 33 μM and 98 μM for dopamine and ascorbic acid, respectively. The quenching constants determined from Stern-Volmer plot were determined to be 5 × 10−4 and 1 × 10−4 for dopamine and ascorbic acid, respectively. A probable mechanism of quenching has been discussed in the paper. Upama Baruah, Neelam Gogoi, Achyut Konwar, Manash Jyoti Deka, Devasish Chowdhury, and Gitanjali Majumdar Copyright © 2014 Upama Baruah et al. All rights reserved. Synthesis of Platinum Nanoparticles from K2PtCl4 Solution Using Bacterial Cellulose Matrix Sun, 14 Dec 2014 07:15:31 +0000 Platinum (Pt) nanoparticles have been synthesized from a precursor solution of potassium tetrachloroplatinate (K2PtCl4) using a matrix of bacterial cellulose (BC). The formation of Pt nanoparticles occurs at the surface and the inside of the BC membrane by reducing the precursor solution with a hydrogen gas reductant. The Pt nanoparticles obtained from the variations of precursor concentration, between 3 mM and 30 mM, and the formation of Pt nanoparticles have been studied using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and thermogravimetry analysis (TGA). Based on X-ray diffraction patterns, Pt particles have sizes between 6.3 nm and 9.3 nm, and the Pt particle size increases with an increase in precursor concentration. The morphology of the Pt nanoparticles was observed by SEM-EDS and the content of Pt particles inside the membrane is higher than that on the surface of BC membranes. This analysis corresponds to the TGA analysis, but the TGA analysis is more representative in how it describes the content of Pt particles in the BC membrane. H. F. Aritonang, D. Onggo, C. Ciptati, and C. L. Radiman Copyright © 2014 H. F. Aritonang et al. All rights reserved. Aqueous Colloidal Stability of Graphene Oxide and Chemically Converted Graphene Thu, 13 Nov 2014 00:00:00 +0000 Graphene oxide (GO) was prepared by modified Hummer’s method, and chemically converted graphene (CCG) was prepared by further reduction of the aqueous GO colloid. The effect of pH on particle size, particle charge, and light absorption of the aqueous colloids of GO and CCG was studied with titration against HCl or NaOH, to find the ideal characteristics for a stable dispersion. The GO colloid was stable in the pH range of 4–11, whereas the CCG colloid gained stability at a relatively narrower pH range of 7–10. Poor stability of the colloids was observed for both GO and CCG colloids at both extremes of the pH scale. Both of the colloids exhibited average size of ~1 micron in the low pH range, whereas for higher pH the size ranged between 300 and 500 nm. The UV-Vis spectra showed absorption peak at 230 nm for GO colloids that shifted to 260 nm for the CCG colloid. Such shift can be ascribed to restoring of electronic conjugation of the C=C bonds in CCG. Swarnima Kashyap, Shashank Mishra, and Shantanu K. Behera Copyright © 2014 Swarnima Kashyap et al. All rights reserved. Spectropolarimetric Properties of a Gallium Nanoparticle Layer on a Sapphire Substrate Sun, 02 Nov 2014 13:47:49 +0000 Gallium nanoparticles (Ga NPs) are currently the subject of vigorous research as possible substrates in surface-enhanced Raman scattering (SERS) experiments in the ultraviolet spectral domain. Verification of any comprehensive model of the interaction of electromagnetic radiation with Ga NPs requires that complete polarimetric measurements be made. These spectropolarimetric properties can be obtained using a Mueller matrix spectropolarimeter (MMSP). The position of localized surface plasmon resonances (LSPRs) and spectral depolarization data of Ga NPs in the 300 to 1100 nm spectral region are presented. Spectral depolarization data may be of value in creating a better understanding of how light couples to individual nanoparticles, as well as the role played by interparticle coupling and the connection to phenomena such as SERS. Prashant Raman, Kirk Fuller, and Don A. Gregory Copyright © 2014 Prashant Raman et al. All rights reserved. Plasmonic and Thermooptical Properties of Spherical Metallic Nanoparticles for Their Thermoplasmonic and Photonic Applications Tue, 14 Oct 2014 00:00:00 +0000 Investigations and use of nanoparticles (NPs) as photothermal (PT) agents in laser and optical nanotechnology are fast growing areas of research and applications. The potential benefits of NPs applications include possibility for thermal imaging and treatment of materials containing of NPs, applications of NPs for light-to-thermal energy conversion, in catalysis, laser nanomedicine, and chemistry. Efficiency of applications of metallic NPs for laser and optical nanotechnology depends on plasmonic and thermophysical properties of NPs, characteristics of radiation, and surrounding medium. Here we present the results of comparative analysis of NP properties (plasmonic, thermooptical, and others) allowing selecting their parameters for thermoplasmonic and photonic applications. Plasmonic and thermooptical properties of several metallic (aurum, silver, platinum, cobalt, zinc, nickel, titanium, cuprum, aluminum, molybdenum, vanadium, and palladium) NPs are theoretically investigated and analysis of them is carried out. Investigation of the influence of NPs parameters (type of metal, radii, optical indexes, density, and heat capacity of NP material), characteristics of radiation (wavelength and pulse duration), and ambient parameters on plasmonic and thermophysical properties of NPs has been carried out. It was established that maximum value of thermooptical parameter (maximum NP temperature) can be achieved with the use of absorption efficiency factor of NP smaller than its maximum value. Victor K. Pustovalov, Liudmila G. Astafyeva, and Wolfgang Fritzsche Copyright © 2014 Victor K. Pustovalov et al. All rights reserved. Plant-Mediated Green Synthesis of Iron Nanoparticles Thu, 02 Oct 2014 00:00:00 +0000 In the recent years, nanotechnology has emerged as a state-of-the-art and cutting edge technology with multifarious applications in a wide array of fields. It is a very broad area comprising of nanomaterials, nanotools, and nanodevices. Amongst nanomaterials, majority of the research has mainly focused on nanoparticles as they can be easily prepared and manipulated. Physical and chemical methods are conventionally used for the synthesis of nanoparticles; however, due to several limitations of these methods, research focus has recently shifted towards the development of clean and eco-friendly synthesis protocols. Magnetic nanoparticles constitute an important class of inorganic nanoparticles, which find applications in different areas by virtue of their several unique properties. Nevertheless, in comparison with biological synthesis protocols for noble metal nanoparticles, limited study has been carried out with respect to biological synthesis of magnetic nanoparticles. This review focuses on various studies outlining the novel routes for biosynthesis of these nanoparticles by plant resources along with outlining the future scope of work in this area. Mihir Herlekar, Siddhivinayak Barve, and Rakesh Kumar Copyright © 2014 Mihir Herlekar et al. All rights reserved. Synthesis of Silver Nanoparticles in Photosynthetic Plants Thu, 25 Sep 2014 11:31:06 +0000 Nanobiotechnology is emerging as a field of applied biological science and nanotechnology. Synthesis of nanoparticles is done by various physical and chemical methods but the biological methods are relatively simple, cost-effective, nontoxic, and environmentally friendly methods. The present review focuses on the synthesis of nanoparticles with special emphasis on the use of plants parts for the synthesis process, its applications, and future prospectus. Ram Prasad Copyright © 2014 Ram Prasad. All rights reserved. Preparation of Cerium Orthophosphate Nanosphere by Coprecipitation Route and Its Structural, Thermal, Optical, and Electrical Characterization Tue, 16 Sep 2014 08:27:26 +0000 Cerium orthophosphate (CePO4) nanoparticles were synthesized via wet chemical coprecipitation technique using cerium nitrate hexahydrate for Ce3+ ion and ammonium dihydrogen phosphate for ion source. X-ray diffraction (XRD) analysis suggests that the material belongs to monoclinic crystal system with crystallite size of 49.3 nm. Scanning electron microscope (SEM) and transmission electron microscope (TEM) reveal the surface morphology of the prepared nanoparticles as nanospheres having grain size in the range of 30–50 nm. The energy dispersive X-ray analysis (EDAX) gives elemental composition present in the grown nanomaterial. Thermogravimetric analysis suggests that the structural phase transition is above 800°C. The optical properties include UV-VIS-NIR absorption and the photoluminescence spectrum shows the absorption and emission peaks in the ultraviolet region. The dielectric constant and ac conductivity properties were investigated with regard to change in temperature (40 to 500°C) and frequency (5 kHz to 1 MHz). The dielectric measurement indicates that the transition is diffused and the activation energy values decrease suggesting that the conduction mechanism is due to hopping of the charge carriers from one site to another. Seema Verma and K. K. Bamzai Copyright © 2014 Seema Verma and K. K. Bamzai. All rights reserved. Biogenic Synthesis of Silver Nanoparticles Using Scenedesmus abundans and Evaluation of Their Antibacterial Activity Sun, 14 Sep 2014 00:00:00 +0000 Silver nanoparticle (AgNP) was synthesized using the cell free extract of Scenedesmus abundans with AgNO3. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), and Photoluminescence. Bioreduction of Ag+ ions showed a gradual change in the colour of the extract and nanoparticles were synthesized having the range of 420–440 nm under UV-visible spectrum. The antibacterial efficacy was assessed against pathogenic bacteria E. coli, Klebsiella pneumoniae, and Aeromonas hydrophila. The present study revealed that the AgNPs prepared from Scenedesmus abundans show antibacterial efficacy against the test pathogens. The bioaccumulation of silver particles makes the organism potential candidate for ecofriendly silver biorecovery system and S. abundans can be used as a source of silver nanoparticles. Nafe Aziz, Tasneem Fatma, Ajit Varma, and Ram Prasad Copyright © 2014 Nafe Aziz et al. All rights reserved. Role of Surfactant in the Formation of Gold Nanoparticles in Aqueous Medium Wed, 10 Sep 2014 05:47:12 +0000 The stability of gold nanoparticles is a major issue which decides their impending usage in nanobiotechnological applications. Often biomimetically synthesized nanoparticles are deemed useless owing to their instability in aqueous medium. So, surfactants are used to stabilize the nanoparticles. But does the surfactant only stabilize by being adsorbed to the surface of the nanoparticles and not play significantly in moulding the size and shape of the nanoparticles? Keeping this idea in mind, gold nanoparticles (GNPs) synthesized by l-tryptophan (Trp) mediated reduction of chloroauric acid (HAuCl4) were stabilized by anionic surfactant, sodium dodecyl sulphate (SDS), and its effect on the moulding of size and properties of the GNPs was studied. Interestingly, unlike most of the gold nanoparticles synthesis mechanism showing saturation growth mechanism, inclusion of SDS in the reaction mixture for GNPs synthesis resulted in a bimodal mechanism which was studied by UV-Vis spectroscopy. The mechanism was further substantiated with transmission electron microscopy. Zeta potential of GNPs solutions was measured to corroborate stability observations recorded visually. Abhishek Das, Ridhima Chadha, Nandita Maiti, and Sudhir Kapoor Copyright © 2014 Abhishek Das et al. All rights reserved. A Simple Approach to Engineer SERS Substrates and Plasmonic Thin Film Mon, 25 Aug 2014 11:02:01 +0000 Solid supported 2D assembly of silver nanocubes was fabricated by Langmuir-Blodgett technique and employed to investigate its surface enhanced Raman scattering (SERS) and surface enhance fluorescence (SEF) activities by detecting Rh6G in solution of varied concentrations, that is, 10−12 M, 10−9 M, 10−6 M, and 10−3 M. SERS was detected from a nanomolar concentration of Rh6G whereas SEF was detected from a picomolar concentration. Further, the substrate was subjected to thermal annealing to fabricate plasmonic thin film. The formation of thin film was followed by monitoring its surface plasmon resonance spectra and atomic force microscopic images. It was observed that the characteristic spectral peaks of silver nanocubes merged into a broad spectral band as the annealing time was increased and the intensity of the band decreased with the formation of thin film. The obtained result implies that thermal annealing could be a simple approach to create nanoscale gaps in SERS substrate and to engineer continuous thin film from the assembly of discrete nanoparticles. Nur Uddin Ahamad, Md. Al-Amin, and Anatoli Ianoul Copyright © 2014 Nur Uddin Ahamad et al. All rights reserved. Biosynthesis of Silver Nanoparticles by Marine Invertebrate (Polychaete) and Assessment of Its Efficacy against Human Pathogens Thu, 21 Aug 2014 00:00:00 +0000 Synthesis of metallic nanoparticles by chemical and physical method makes the process often cumbersome due the usage of toxic and expensive chemicals. The present study reports the biosynthesis of silver nanoparticles using marine invertebrate (polychaete) extract at room temperature. The ultraviolet-visible (UV-Vis) spectroscopy revealed the formation of silver nanoparticles (AgNPs) by exhibiting the typical surface plasmon absorption maximum at 418–420 nm. Structure and composition of AgNPs were analyzed by atomic force microscopy (AFM). Average particle size of AgNPs ranged from 40 to 90 nm, confirmed by scanning electron microscopy (SEM) analysis. The energy-dispersive X-ray spectroscopy (EDX) of the nanoparticles dispersion confirmed the presence of elemental silver signal, whereas X-ray diffraction (XRD) substantiated the crystalline nature of synthesized nanoparticle. Fourier transform infrared spectroscopy (FTIR) spectral analysis showed the presence of amides phenols, ethers, and fatty acids as major biomolecules responsible for the reduction of silver ions. The possible mechanism responsible for the synthesis of AgNPs by these biomolecules was also illustrated by chemical reactions. The synthesized AgNPs showed comparatively good antibacterial activity against the tested human pathogens. This study advocates that not only plants and microbes but also marine invertebrates do have potential for synthesizing nanoparticles by a cost-effective and eco-friendly approach. Reena Singh, Sunil Kumar Sahu, and Muthusamy Thangaraj Copyright © 2014 Reena Singh et al. All rights reserved. Magnetic Fluid Hyperthermia of Rodent Tumors Using Manganese Perovskite Nanoparticles Thu, 14 Aug 2014 11:33:37 +0000 Purpose. To test the antitumor activity of magnetic fluid (MF) on the basis of substituted lanthanum-strontium manganite nanoparticles combined with alternating magnetic field (AMF) in experiments with transplanted tumors. Materials and Methods. MF with a size of nanoparticles of 30–40 nm in aqueous agarose solution was investigated. The ability of MF to heat tumor under AMF (300 kHz, 7.7 kA/m) was tested in vivo with rodent tumors (Guerin carcinoma, Walker-256 carcinosarcoma, and Lewis lung carcinoma (3LL)). Results. Single administration of MF into the tumor at a dose of 150 mg/kg (rats) or 200 mg/kg (mice) followed by AMF within 20–30 min (treatment was repeated 3-4-fold) has resulted in the complete regression of tumor in the 35% of rats and 57% of mice. Administration of MF alone or action of AMF alone has not resulted in tumor growth inhibition. The chemomodifying effect of nanohyperthermia was determined, in particular for cisplatinum: thermal enhancement ratio was 2.0. It was also observed that nanohyperthermia has resulted in the absence of 3LL metastases in 43% of mice. Conclusions. MF on the basis of lanthanum-strontium manganite may be considered as an effective inductor of tumor local hyperthermia. Larissa Bubnovskaya, Anatolij Belous, Sergej Solopan, Antonina Kovelskaya, Lyudmila Bovkun, Alexander Podoltsev, Igor Kondtratenko, and Sergej Osinsky Copyright © 2014 Larissa Bubnovskaya et al. All rights reserved. Response Surface Modelling of Electrosprayed Polyacrylonitrile Nanoparticle Size Sun, 10 Aug 2014 11:30:48 +0000 Electrospraying (electrohydrodynamic spraying) is a method of liquid atomization by electrical forces. Spraying solutions or suspensions allow production of fine particles, down to nanometer size. These particles are interesting for a wide variety of applications, thanks to their unprecedented chemical and physical behaviour in comparison to their bulk form. Knowledge of the particle size in powders is important in many studies employing nanoparticles. In this paper, the effect of some process parameters on the size of electrosprayed polyacrylonitrile particles is presented in the form of response surface model. The model is achieved by employing a factorial design to evaluate the influence of parameters on the polyacrylonitrile nanoparticle size and response surface methodology. Four electrospraying parameters, namely, applied voltage, electrospraying solution concentration, flow rate, and syringe needle diameter were considered. Sanaz Khademolqorani, Ali Zeinal Hamadani, and Hossein Tavanai Copyright © 2014 Sanaz Khademolqorani et al. All rights reserved. Synthesis and the Structural Transformation of fcc to hcp in Ni-Graphene Nanocomposite by Simple Chemical Route via Sonication Mon, 23 Jun 2014 11:38:55 +0000 We report the synthesis and structural transformation of fcc to hcp in Ni-graphene (Ni-Gr) composite by simple chemical route via sonication. The syntheses of Ni-Gr composite by simultaneous reduction method, and the effect of different composition ratio on morphology and crystal structure were examined in our present study. The results indicated that the graphene ratio played an important role in crystal structure and d-spacing in nickel crystals. Different compositions have shown different behavior. The nanonickel clusters of various shapes with coated graphene and decorated as nickel on graphene sheets are observed. The synthesized composites were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscope (TEM). The XRD patterns indicated crystal lattice modifications in some composites while composites with a higher graphene ratio produced very small crystals with uniform lattice parameter and d-spacing. FE-SEM images indicated the growth of Datura fruit like shapes of nickel clusters in higher composition of nickel while the composites with least concentration of nickel were composed of cubical nanoparticles grown on graphene sheets. TEM analysis revealed many Ni nanoparticles surrounding the smooth petals like surface of graphene, with average diameters of spiky nickel nanoparticles being about 50 nm and 124 nm, respectively, on 200 nm of scale. N. K. Mahale, R. D. Ladhe, S. B. Attarde, and S. T. Ingle Copyright © 2014 N. K. Mahale et al. All rights reserved. Optical and Structural Properties of ZnO Nanoparticles Synthesized by CO2 Microwave Plasma at Atmospheric Pressure Mon, 23 Jun 2014 11:17:41 +0000 The results of carbon-doped zinc oxide nanoparticles synthesized by CO2 microwave plasma at atmospheric pressure are presented. The 2.45-GHz microwave plasma torch and feeder for injecting Zn granules are used in the synthesis of zinc oxide nanoparticles. The Zn granules (13.5 g/min) were introduced into the microwave plasma by CO2 (5 l/min) swirl gas. The microwave power delivered to the CO2 microwave plasma was 1 kW. The synthesis of carbon-doped zinc oxide nanoparticles was carried out in accordance with CO2 + Zn → carbon-doped ZnO + CO. The synthesized carbon-doped zinc oxide nanoparticles have a high purity hexagonal phase. The absorption edge of carbon-doped zinc oxide nanoparticles exhibited a red shift from a high-energy wavelength to lower in the UV-visible spectrum, due to band gap narrowing. A UV-NIR spectrometer, X-ray diffraction, emission scanning electron-microscopy, energy dispersive X-ray microanalysis, Fourier transform infrared spectroscopy, and a UV-Vis-NIR spectrophotometer were used for the characterization of the as-produced products. Se Min Chun, Dae Hyun Choi, Jong Bae Park, and Yong Cheol Hong Copyright © 2014 Se Min Chun et al. All rights reserved. Ecofriendly Application of Nanomaterials: Nanobioremediation Thu, 19 Jun 2014 11:03:20 +0000 Nanomaterials exhibit unique physical and chemical properties and, hence, they have received much attention from scientists and researchers in different areas of environmental sciences, specifically in bioremediation. Bioremediation provides a good clean-up strategy for some types of waste, but as it is expected, it will not be useful for all. For example, bioremediation may not provide a feasible strategy at sites with high concentrations of chemicals that are toxic to most microorganisms. These include heavy metals and salt. Further, the advancement in science and technology has increased standard of living which directly or indirectly contributes to the increase in waste and toxic material. Therefore, the remediation of contaminants by use of existing technology is not effective and efficient in cleaning up the environment. Hence, nanomaterials may be applied for bioremediation, which will not only have less toxic effect on microorganisms, but will also improve the microbial activity of the specific waste and toxic material which will reduce the overall time consumption as well as reduce the overall cost. In this paper we have briefly summarized the major types of nanomaterials that have been used so far in bioremediation of waste and toxic materials. Md. Rizwan, Man Singh, Chanchal K. Mitra, and Roshan K. Morve Copyright © 2014 Md. Rizwan et al. All rights reserved. Studies on the Iron Nanoparticles Catalyzed Reduction of Substituted Aromatic Ketones to Alcohols Wed, 11 Jun 2014 09:31:49 +0000 Iron nanoparticles are synthesized and size characterized using HRTEM, FESEM, and XRD. Polyethylene glycol(PEG), carboxymethyl cellulose (CMC), and poly N-vinyl pyrrolidone (PVP) are used as nanoparticle stabilizers. The sizes of Fe nps are found to be 9 nm, 14 nm, and 17 nm ± 1 nm corresponding to PEG, CMC, and PVP stabilizers, respectively. The three different iron nanoparticles (Fe nps) prepared are used as catalysts in the hydrogenation reaction of various substituted aromatic ketones to alcohols with NaBH4. The progress of the reaction was monitored using time variance UV spectra. Kinetic plots are made from the absorbance values and the pseudo first order rate coefficient values are determined. Catalytic efficiency of the Fe nps is obtained by comparing the pseudo first order rate coefficient values, times of reaction, and % yield. Fe-PEG nps was found to act as better catalyst than Fe-CMC nps and Fe-PVP nps. Also, effects of substituents in the aromatic ring of ketones reveal that +I substituents are better catalysed than –I substituents. L. Parimala and J. Santhanalakshmi Copyright © 2014 L. Parimala and J. Santhanalakshmi. All rights reserved. Microwave Assisted Biosynthesis of Silver Nanoparticles Using the Rhizome Extract of Alpinia galanga and Evaluation of Their Catalytic and Antimicrobial Activities Tue, 13 May 2014 12:17:54 +0000 Biomediated methods are considered to be a safer alternative to conventional physicochemical methods for the fabrication of nanomaterials due to their eco-friendly nature. In the present study, silver nanoparticles (AgNPs) were synthesized by microwave irradiation using aqueous rhizome extract of the medicinal plant Alpinia galanga. The nanoparticles were also synthesized under ambient condition without the assistance of microwave radiation and the former method was found to be much faster than the latter. The silver nanoparticles were characterized by UV-vis., FTIR, XRD, and HR-TEM analysis. UV-vis. spectroscopic studies provided ample evidences for the formation of nanoparticles. The FTIR spectrum confirmed the presence of plant phytochemicals as stabilizing agent around the AgNPs. XRD and HR-TEM analyses clearly proved the crystalline nature of the nanoparticles. From the TEM images, the nanoparticles were found to be roughly spherical in shape with an average diameter of 20.82 ± 1.8 nm. The nanoparticles showed outstanding catalytic activity for the reduction of methyl orange by NaBH4. The AgNPs were also evaluated for their antimicrobial activity by well diffusion method against S. aureus, B. subtilis, V. cholera, S. paratyphi, and A. niger. They were found to be highly toxic against all the tested pathogenic strains. Siby Joseph and Beena Mathew Copyright © 2014 Siby Joseph and Beena Mathew. All rights reserved. Copper Oxide Nanoparticles for Advanced Refrigerant Thermophysical Properties: Mathematical Modeling Wed, 30 Apr 2014 12:54:49 +0000 In modern days, refrigeration systems are important for industrial and domestic applications. The systems consume more electricity as compared to other appliances. The refrigeration systems have been investigated thoroughly in many ways to reduce the energy consumption. Hence, nanorefrigerant which is one kind of nanofluids has been introduced as a superior properties refrigerant that increased the heat transfer rate in the refrigeration system. Many types of materials could be used as the nanoparticles to be suspended into the conventional refrigerants. In this study, the effect of the suspended copper oxide (CuO) nanoparticles into the 1,1,1,2-tetrafluoroethane, R-134a is investigated by using mathematical modeling. The investigation includes the thermal conductivity, dynamic viscosity, and heat transfer rate of the nanorefrigerant in a tube of evaporator. The results show enhanced thermophysical properties of nanorefrigerant compared to the conventional refrigerant. These advanced thermophysical properties increased the heat transfer rate in the tube. The nanorefrigerant could be a potential working fluid to be used in the refrigeration system to increase the heat transfer characteristics and save the energy usage. S. A. Fadhilah, R. S. Marhamah, and A. H. M. Izzat Copyright © 2014 S. A. Fadhilah et al. All rights reserved. Influence of Gas Sort on the Nucleation Region Width of Si Nanocrystal Grains Prepared by Pulsed Laser Ablation Sun, 30 Mar 2014 11:23:08 +0000 We have calculated the nucleation region (NR) location of Si nanocrystal grains prepared by pulsed laser ablation (PLA) with fluence of 4 J/cm2 in 10 Pa gas at room temperature, and ambient gases were He, Ne, and Ar, respectively. Results of calculation indicated that NR width in Ne gas was narrowest, while it was widest in He gas. Maximum mean size of grains deposited on substrates under ablated spot, which were placed horizontally, was the smallest in Ne gas. It would be attribute to more effective energy transfer during the process of collision when atomic mass of Si and ambient gas Ne are more close to each other. In this work, an additional gas flow with the same element as ambient gas was introduced, which is vertical to the plume axis at different lateral positions above ablated spot. Zechao Deng, Lizhi Chu, Xuecheng Ding, Aili Qin, Guangsheng Fu, and Yinglong Wang Copyright © 2014 Zechao Deng et al. All rights reserved. Green Chemistry Based Benign Routes for Nanoparticle Synthesis Mon, 24 Mar 2014 07:41:33 +0000 Green chemistry has been an eye catching area of interest since the past few years. With the problem of energy crisis looming high and its constraint being particularly vulnerable on the developing economies, the need for giving alternative traditional chemistry a serious consideration as well as adequate room for development has received significant boost through the coveted efforts of multidisciplinary and interdisciplinary scientific fields. Nanoscience has been the right field in this dimension as it opens up the door to multiple opportunities through enabling a number of chemical, biochemical, and biophysical transformations in a significantly easier and reliable manner. The use of nanoparticles has made the fields of catalysis, synthesis, and enzyme immobilizations as well as molecular interactions a lot much easier, rapid and easily controllable. This review article sheds light on the popular alternative synthesis routes being employed for the synthesis of nanoparticles, the pivotal being from microbes, plants, and chemical routes via sonication, microwaving, and many others. Parth Malik, Ravi Shankar, Vibhuti Malik, Nitin Sharma, and Tapan Kumar Mukherjee Copyright © 2014 Parth Malik et al. All rights reserved. Performance of Water-Based Zinc Oxide Nanoparticle Coolant during Abrasive Grinding of Ductile Cast Iron Wed, 05 Mar 2014 09:49:27 +0000 This paper presents the performance of ductile cast iron grinding machining using water-based zinc oxide nanoparticles as a coolant. The experimental data was utilized to develop the mathematical model for first- and second-order models. The second order gives worthy performance of the grinding. The results indicate that the optimum parameters for the grinding model are 20 m/min table speed and 42.43 μm depth of cut for single-pass grinding. For multiple-pass grinding, optimization is at a table speed equal to 35.11 m/min and a depth of cut equal to 29.78 μm. The model fit was adequate and acceptable for sustainable grinding using a 0.15% volume concentration of zinc oxide nanocoolant. This paper quantifies the impact of water-based ZnO nanoparticle coolant on the achieved surface quality. It is concluded that the surface quality is the most influenced by the depth of cut(s) and table speed. M. M. Rahman and K. Kadirgama Copyright © 2014 M. M. Rahman and K. Kadirgama. All rights reserved. The Mode of Action of Silver and Silver Halides Nanoparticles against Saccharomyces cerevisiae Cells Thu, 13 Feb 2014 16:12:34 +0000 Silver and silver halides nanoparticles (NPs) (Ag, AgCl, AgBr, and AgI) capped with two different stabilizers (sodium citrate and nonionic surfactant Tween 80) were obtained via sodium borohydride reduction of silver nitrate in an aqueous solution. The effect of the biocidal action of as-prepared synthesized materials against yeast cells Saccharomyces cerevisiae was compared to the effect produced by silver nitrate and studied through the measurement of cell loss and kinetics of K+ efflux from the cells depending on concentration of silver. The results clearly indicate that the silver ions either remained in the dispersion of silver NPs and silver halides NPs after their synthesis or were generated afterwards by dissolving silver and silver halides particles playing a major part in the cytotoxic activity of NPs against yeast cells. It was also supposed that this activity most likely does not relate to the damage of cell membrane. A. A. Kudrinskiy, A. Yu. Ivanov, E. V. Kulakovskaya, A. I. Klimov, P. M. Zherebin, D. V. Khodarev, Anh-Tuan Le, Le Thi Tam, G. V. Lisichkin, and Yu. A. Krutyakov Copyright © 2014 A. A. Kudrinskiy et al. All rights reserved. Small Angle X-Ray Scattering Technique for the Particle Size Distribution of Nonporous Nanoparticles Sun, 22 Dec 2013 09:44:57 +0000 Nanoparticles are small particles whose sizes are less than 100 nm. They have many industrial applications due to their unique properties. Their properties are often size-dependent; thus the accurate determination of nanoparticle sizes is important for quality assurance of nanoparticle production processes. A small angle X-ray scattering technique is a promising method used for characterizing nanoparticle sizes. It has distinctive advantages over other techniques such as electron microscope techniques. In this paper, we review the state-of-the-art methods for determining the sizes of nanoparticles with small angle X-ray experiments and discuss the advantages and limitations of the state-of-the-art methods. A. Agbabiaka, M. Wiltfong, and C. Park Copyright © 2013 A. Agbabiaka et al. All rights reserved. Magnetization and Specific Absorption Rate Studies of Ball-Milled Iron Oxide Nanoparticles for Biomedicine Sat, 28 Sep 2013 14:48:37 +0000 Comparative studies are presented of iron oxide nanoparticles in the 7–15 nm average diameter range ball milled in hexane in the presence of oleic acid. Transmission electron microscopy identified spherical particles of decreasing size as milling time and/or surfactant concentration increased. Micromagnetic characterization via Mössbauer spectroscopy at room temperature yielded broadened magnetic spectroscopic signatures, while macromagnetic characterization via vibrating sample magnetometry of 7-8 nm diameter particles showed largely superparamagnetic behavior at room temperature and hysteretic at 2 K. Zero-field and field-cooled magnetization curves exhibited a broad maximum at ~215 K indicating the presence of strong interparticle magnetic interactions. The specific absorption rates of ferrofluids based on these nanoparticle preparations were measured in order to test their efficacies as hyperthermia agents. P. Burnham, N. Dollahon, C. H. Li, A. J. Viescas, and G. C. Papaefthymiou Copyright © 2013 P. Burnham et al. All rights reserved. Characterization and Modification of Mesoporous Silica Nanoparticles Prepared by Sol-Gel Wed, 25 Sep 2013 15:50:22 +0000 Mesoporous silica nanoparticles (MSNs) were synthesized by sol-gel reaction at normal pressure by using TEOS as a silica source and CTAB as a directing agent in ammonia solution at 323 K subsequently calcined at 823 K. Then inorganic pores were modified with metal-supported MSN with attention to the acidity, surface area, pore size, and ability of ion exchange. Crystalline size was shown to decrease up to 20 molar ratios of Si/Al followed by increasing while further adding nanoparticles-aluminium. Moreover, the XRD patterns revealed the mesostructured material for all with 2D hexagonal structure. The obtained results from the XRD patterns were confirmed by using BET and EDX. The BET surface areas revealed the spherical shape for all samples with a decrease in the pore volume and surface area for various AlMSNs which emphasized that the loading of Al and was compatible with XRD results. MSN was prepared by sol-gel methods followed by loading of Al in order to prepare AlMSN which possess strong Lewis acidic sites. This modification occurred by using various molar ratios of 0, 5, 10, 20, 50, and 100 Si/Al, respectively. The XRD patterns of various ratios of Si/Al were interpreted in terms of strain, nanocrystalline size, and distribution of the particle size by deriving Wiliamson Hall equation. Meysam Keshavarz and Norhayati Ahmad Copyright © 2013 Meysam Keshavarz and Norhayati Ahmad. All rights reserved. Dependence Properties of Sol-Gel Derived CuO@SiO2 Nanostructure to Diverse Concentrations of Copper Oxide Thu, 19 Sep 2013 10:34:09 +0000 Various concentrations of copper oxide were embedded into silica matrix of xerogel forms using copper source Cu(NO3)2·3H2O. The xerogel samples were prepared by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) with determination of new molar ratios of the components by the sol-gel method. In this paper, three samples of copper oxide were doped into silica matrices using different concentrations. We obtained 10, 20, and 30 wt.% of copper oxide in silica matrices labeled as A, B, and C, respectively. The absorption and transmittance spectra of the gel matrices were treated at different concentrations by Uv-vis spectrophotometer. Quantities of water and transparency in the silica network change the spectral characteristics of Cu2+ ions in the host silica. Absorption spectra of the samples heated to higher concentration complete the conversion of Cu2+ ions to Cu+ ions. The effects of concentration of copper oxide were characterized by X-ray diffraction (XRD) patterns, and the transmission electron microscope (TEM) micrographs. Also, textural properties of samples were studied by surface area analysis (BET method) at different concentrations. V. Homaunmir, S. H. Tohidi, G. Grigorya, and M. Ayatollah Zada Shirazi Copyright © 2013 V. Homaunmir et al. All rights reserved. Condensation Energy for a Two-Gap Superconducting State in Nanoparticles Wed, 04 Sep 2013 13:30:17 +0000 Recent technology and experiments have fabricated high-quality superconducting MgB2 nanoparticles. We investigate properties of two-gap superconductivity in nanosized systems by using a two-sublevel model. In the present work, we analyze the results obtained for superconducting granules in the case of multiband superconductivity. We discuss the finite size effect in multiband superconductors. A definition of the critical level spacing of two-gap superconductivity is also presented, and we discuss the condensation energy and the parity gap of two-gap superconductivity in relation to the size dependence of those properties with two bulk gaps and the effective pair scattering process between two sublevels. Sergei P. Kruchinin, Hiroyuki Kawabe, Hidemi Nagao, and Yasuhiro Nakazawa Copyright © 2013 Sergei P. Kruchinin et al. All rights reserved.