bluuebunny/crossref_metadata_2025 huggingface dataset:
PEG Decorated Glycine Capped Mn-Ferrite Nanoparticles Synthesized by Co-Precipitation Method for Biomedical Application
Authors: Faham Mahdokht , Shokrollahi Hooman , Yousefi Gholamhossein , Abbasi Sahar
Published: November 2013

Our goal is to develop methoxy poly (ethylene glycol) (m-PEG) decorated, glycine capped magnetic nanoparticles (MNPs) with proper physicochemical characteristics including particle size and magnetic property. MNP were synthesized by a biocompatible chemical co-precipitation of Mn2+and Fe3+in a sodium hydroxide solution. In order to covalently modify nanoparticles surface by previously prepared m-PEG aldehyde, glycine was used as linker. X-ray diffraction analysis showed successful formation of pure nanocrystalline single phase of Mn-Ferrite and FT-IR spectroscopy approved that m-PEG and glycine were covalently bound to nanoparticles surface. Particle size study showed significant change after modification. In addition, the Vibrating sample magnetometry was done for measuring the magnetic properties (Ms: 52 emu/g) and showing the superparamagnetism behavior.
The Effect of Ultrasound Wave on Levothyroxine Release from Chitosan Nanoparticles
Authors: Rostami Elham , Kashanian Soheila , Askari Mehran
Published: November 2013

A nanoparticle polymer has been developed as a potential platform for drug delivery. Chitosan nanoparticles were prepared with tripolyphosphate (TPP) by the ionic crosslinking method. The particle size of chitosan nanoparticles was in the range of 190-250 nm and encapsulation efficiencies of levothyroxine were 85%. The particle size was determined by photon correlation spectroscopy (PCS). Shape and surface morphology were determined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). They revealed fairly spherical shape of nanoparticles. A non-invasive way to deliver drugs to the deepest parts of the human body is ultrasound. To study how ultrasound causes levothyroxine to be released from chitosan nanoparticles, cumulative release was examined. In this report, we explore the effect of ultrasound and tripolyphosphate (TPP) concentration on release behavior of levothyroxine from chitosan nanoparticles. The drug release from chitosan nanoparticles was enhanced using the ultrasound wave.
Synthesis of Nanostructured Zinc Oxide Thin Films by Anodic Oxidation Method
Authors: Ravanbakhsh Arsalan , Rashchi Fereshteh , Sohi M. Heydarzadeh , Nekouei Rasoul Khayyam
Published: November 2013

In this study, the ZnO thin film was synthesized by means of anodic oxidation method. A basic solution containing NaOH and NH4Cl as additive was used for the process. Effect of time and voltage on the microstructure of the obtained thin film has been studied. Characterization has been performed using grazing incidence X-ray diffraction (GIXD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). Nanostructured thin film has been obtained with different morphologies according to different process parameters. FESEM analysis indicated that as the process time increases, the morphology of the film changes from grooved surface into flaky porous structure. It was also evident that hexagonal shaped simonkolleite formed during the process which was then transformed into zinc oxide and zinc chloride by heat treating.
Synthesis of Nano Structured Membrane from Carbon Nanotube for Waste Water Treatment
Authors: Imani Mehri , Rashidi Alimorad , Shariaty-Niassar Mojtaba , Sarlak Elahe , Zarghan Amir
Published: November 2013

Carbon membranes have high adsorption capacitiy with respect to its incredible properties such as unique structural, electronic, optoelectronic, semiconductor, mechanical, chemical and physical. Carbon nanotube (CNT) membranes because of its high permeance have been recently developed.Great attention has been currently paid to the field of fabrication methods capable of producing uniform, well-aligned and monodispersed CNT array. Current research concerns with fabrication of vertically aligned CNT membrane in order to remove heavy metal ion presents in waste water. For this purpose, CNTs are vertically grown up through the holes of anodic aluminium oxide (AAO); as a template, by chemical vapor deposition (CVD) of acetylene gas.In this work a few heavy metals such as Pb (II), Cu (II) and Cd (II) has been examined for checking the perfomance of membrane in aqueous solution. The morphological properties of the aligned CNT membrane were investigated with scanning electron microscopy (SEM). The method has simple technology, low cost, and easy reproduction.
Nanomagnetic Poly(vinyl alcohol) Hydrogels
Authors: Asa'di Sima , Frounchi Masoud , Dadbin Susan
Published: November 2013

Surface modified magnetic nanoparticles (M-NPs) were synthetized and stabilized in poly (vinyl-alcohol) solution. The solutions with various magnetic nanoparticles contents were gamma-irradiated and magnetic poly (vinyl-alcohol) (M-PVA) hydrogels were synthesized. The magnetic hydrogels and also the un-irradiated magnetic poly (vinyl alcohol) nanocomposite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR) and mechanical measurement. The M-NPs were uniformly dispersed in the polymer matrix due to a strong interaction between the surface-modified M-NPs and polymer matrix. Physical properties of the M-PVA hydrogels, including gel fraction and equilibrium water content were measured to evaluate the applicability of these hydrogels for biomedical applications. XRD, FTIR and VSM results indicated that there are important changes in crystalline, chemical and magnetic properties of hydrogels, arising from irradiation.
Synthesis and Characterisation of Hematite-Zircon Nanocomposite by Sol-Gel Method
Authors: Heydari Hossein , Naghizadeh Rahim , Samimbanihashemi H.R. , Hosseini-Zori Maryam
Published: November 2013

Hematite widely used since ancient times as a pigment but its chemical and thermal stability at high temperatures application is not enough. In this study, hematite nanoparticles were included into the zircon matrix and its stability was increased. Fe2O3 ZrSiO4 nanocomposite with Fe/Zr molar ratio of 5 to 30% was synthesized from Si and Zr alkoxides by sol-gel method. The products of the solgel method were calcined in the 1200°C /2.5 h. The structural and morphological characteristics of nanocomposite are determined by X-ray diffraction (XRD), simultaneous thermal analysis (STA) and scanning electron microscopy (SEM) investigations. The results indicate that formation of zircon promoted with iron addition. Finally, colorimetric parameters of the glazed ceramic samples were measured by the CIE colorimetric method. It was found that the samples withe 20% molar Fe has the highest red shade and is the best color according to the a* parameter.
Mechanical Properties and Fracture Study of Alumina Dispersion Hardened Copper-Based Nano-Composite at Elevated Temperatures
Authors: Dalirbod Ali , Sorkhe Yahya A. , Aghajani Hossein
Published: November 2013

Alumina dispersion hardened copper-base composite was fabricated by internal oxidation method. The high temperature tensile fracture of Cu-Al2O3 composite was studied and tensile strengths were determined at different temperatures of 600, 680 and 780 °C. Microstructure was investigated by means of optical microscope and field emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS). Results show that, ultimate tensile strength and yield strength of copper alumina nanocomposite decrease slowly with increasing temperature. The yield strength reaches 119 MPa and ultimate tensile strength reaches 132 MPa at 780 °C. Surface fractography shows a dimple-type fracture on the fracture surface of the tensile tests where dimple size increases with increasing testing temperature and in some regions brittle fracture characteristics could be observed in the fracture surface.
Ionic Liquid Aided Chemical Synthesis of Noble Metal Nanocomposites as Efficient Nanoelectrocatalysts
Authors: Sara Djafar Vatan Khah Dowlat , Shamsipur Mojtaba , Rouhollahi Ahmad
Published: November 2013

Platinum, Palladium and Gold nanocomposite using non-functionalized Multiwalled Carbon Nanotube (MWCNTs) has been prepared in the presence of phosphonium-based ionic liquid (Trihexyl Tetradecyl-phosphonium bis (trifluoromethylsulfonyl) amide) TTP(TFMS)2A. In this research, the presence of ascorbic acid (AA) in the quaternary phosphonium ionic liquid and MWCNTs without any modification, different noble metal nanocomposites of Pt, Pd and Au are formed. The mixture of MWCNT and IL has already been well-ultrasonicated until the best possible long-term stable dispersion to be formed. Under the similar time durations and similar concentrations of IL, the synthesis has been carefully performed. Working in these conditions leads to platinum-ionic liquid-MWNTs nanocomposite as black viscose powders. The nanostructures of the as-prepared nanopowders was checked with SEM. Using palladium nanocomposites as the modification agent on the glassy carbon electrode (GCE), the electrocatalytic effect of nanocomposites has been electrochemically investigated. Comparing three nanocomposites show that noble metal nanoparticles well supported on the bundles of MWCNTs but palladium NPs particle density is more than platinum NPs and PtNPs particle density is more than gold one. Anyway, the electrocatalytic activity of nanocomposites changes as PdNPs>PtNPs>AuNPs.
Preparation and Characterization of HAp/TiO2 Nanocomposite for Photocatalytic Degradation of Methyl Orange under UV-Irradiation
Authors: Sharifat Saham , Zolgharnein Hossein , Hamidifalahi Abdolghader , Enayati-Jazi Mahnaz , Hamid Entesar
Published: November 2013

A new in-situ precipitation technique is introduced in this study to prepare hydroxyapatite/titania nanocomposites. This technique provides a better control over the microstructures and phase compositions of nanocomposites. The structure and surface morphology of hydroxyapatite/titania nanocomposite were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy and scanning electron microscopes. The photocatalytic activity of hydroxyapatite/titania nanocomposite was evaluated by photocatalytic decolorization of methyl orange in aqueous solution as a model pollutant under UV-irradiation. X-ray diffraction and Fourier transform infrared results indicated that hydroxyapatite and anatase (TiO2) were the major crystalline phases. There had been no reaction between hydroxyapatite and titania compounds. Based on the SEM images, the overall morphology of the samples indicates that there exists a distribution of small particles and large agglomerates.The hydroxyapatite/titania nanocomposite exhibited high photocatalytic activity hydroxyapatite/titania nanocomposite under UV-irradiation. After 8 h of irradiation by UV-irradiation, over 80% of methyl orange solution (5 mg L-1) was decolorized with 1 gL-1 of the photocatalyst. Since this process does not require the addition of hydrogen peroxide and uses UV-irradiation in this study are environmentally friendly method to decolorize azo dye.
The Effect of Layer Number on the Nanostructural Ternary Mixed Oxide Containing Ti, Ru and Ir on Titanium
Authors: Goudarzi Mona , Ghorbani Mohammad
Published: November 2013

Titanium anodes coated with noble metal oxides are widely used in chlorate industry. In fact, these anodes are dimensionally stable. In this article, the electrochemical characteristics of the ternary oxide coating created by sol-gel on titanium, which consisted of Ti, Ru and Ir, were investigated in the number of different layers. The electrochemical properties of anodes, morphology of samples, and phase analysis were investigated respectively by cyclic voltammetry and polarization measurements, Field Emission Scanning Electron Microscope (FESEM) and XRD. The result indicated that the application of the more layer number increases the rate of chlorine evolution. Also, The morphology of the coatings was cracked structures and cracks in the coating with six layers were distributed uniformly.
Removal of Aluminum from Water and Wastewater Using Magnetic Iron Oxide Nanoparticles
Authors: Asrarian Razieh , Jadidian Reza , Parham Hooshang , Haghtalab Sara
Published: November 2013

Aluminum is the most widely used non ferrous metal, but its considered as a highly toxic element in drinking water at high concentration and the trace aluminum content in food must be controlled. This paper shows effective removal of aluminum from water and industrial wastewater by magnetic nanoparticle. The method is fast, simple, cheap, effective and safe for treatment of aluminum polluted waters. Preparation of adsorbent is easy and removal time is short. magnetic iron oxide nanoparticles (MIONPs) can adsorb up to 99.8% of 60 ng ml-1of Al ions from polluted water. The required time for complete removal of aluminum ions was 3 minutes. Variation of pH and high electrolyte concentration (NaCl) of the solution do not have considerable effect on the aluminum removal efficiency.
Investigation on Phase Evolution in the Processing of Nano-Crystalline Cobalt Ferrite by Solid-State Reaction Route
Authors: Akbari Moayyer Hamid , Ataie Abolghasem
Published: November 2013

Cobalt ferrite nanocrystalline powder was synthesized from the powder mixture of cobalt carbonate and iron oxide by mixed oxide ceramic method. The effects of temperature of calcination as well as molar ratio of CoCO3/Fe2O3on the phase structure, morphology and magnetic properties of the products were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM) techniques, respectively. The samples calcined at 800 and 900 C consisted of cobalt ferrite, iron oxide and cobalt oxide. In the sample calcined at 1000 C, the reaction was completed and single phase CoFe2O4with a mean crystallite and particle sizes of 49 and 300 nm, respectively was obtained. The above sample showed hard magnetic behavior with a coercivity of 337 Oe, saturation magnetization of 76 emu/g and remanence of 19 emu/g.
Effect of Friction Stir Processing on Mechanical Properties of Surface Composite of Cu Reinforced with Cr Particles
Authors: Khiyavi Bahram A. , Aghchai Abdolhossein Jalali , Arbabtafti Mohammadreza , Givi Mohamad Kazem Besharati , Jafari Jalal
Published: November 2013

The main aims of this study is to produce copper reinforced metal matrix composite (MMC) using micron sized chromium particles via friction stir processing (FSP) in order to studying effects of adding Cr particles to copper based matrix by FSP.Microstructures, microhardness and wear properties have been studied in order to evaluate the microstructures and mechanical properties of fabricated composites. the microstructure properties are evaluated by optical microscopy (OM) and field emission scanning electron microscopy (FESEM). The mechanical behaviors of the samples are determined by microhardness and wear tests. The results showed that the grain size of fabricated composite reduced. also it is indicated that in comparison to base copper microhardness of FSPed composites in stir zone (SZ) have been increased significantly. the results of wear test showed that in comparison with specimen with traverse speed of 80 mm/min , higher traverse speed of 160 mm/min increase wear rate of cylindrical pins.
Boundary Element Analysis of Accelerated Chloride Diffusion in High Performance Concrete
Authors: Wang Yi , Hang Wo Cheng , Yang Lu Feng , Chen Zheng
Published: November 2013

This paper aims to analyze accelerated chloride diffusion in high performance concrete (HPC) blended with mineral admixture by using boundary element method (BEM). Rapid chloride permeability test (RCPT) was employed and executed. The experiment proves that the highest resistance to chloride permeability can be acquired in the quaternary-blended concretes (ordinary portland cement + fly ash + blast furnace slag + silica fume). A chloride diffusion BEM model was established according to the diffusion coefficient calculated from the charge passed. The numerical solutions agree with experiments well. It can be inferred that the acceleration degree of RCPT is not the same in different mix proportion. Besides, the results also suggest that the low chloride permeability of the concretes with mineral admixtures may be attributed to the lower diffusion coefficient and the lower surface chloride concentration.
Different Performance of Foam Concrete Caused by Two Types of Fiber
Authors: Cai Yan Da , Wang Jing Song , Luo Yun Feng , Long Wen Wu , Yang Xiao Feng , Zhu Feng
Published: November 2013

400kg/m3 apparent density foam concrete consists of protein foaming agent, ordinary Portland cement and two types of polypropylene fibers is made in this study. The effects of two types of fibers (polypropylene linear fiber and polypropylene mesh fiber) on the compressive strength, flexural strength and water absorption of the foam concrete were investigated. The results showed the difference of the water absorption of the foam concrete with addition of the two types of fibers is not significant, but the difference of the compressive strength and flexural strength is clear. Moderate addition of fibers could improve the strength of the foam concrete. As compared with control, the compressive strength and flexural strength increased by as high as 60.7% and 71.2%, respectively. From the experimental results, it is clear that polypropylene linear fiber has advantage of compressive strength and flexural strength over polypropylene mesh fiber when mixed with foam concrete.
Tensile Properties of 15wt. %TiB2/7055 Composite Fabricated by In Situ Method
Authors: Chen Dong , Zou Cong , Zhang Yi Jie , Ma Nai Heng , Wang Hao Wei
Published: November 2013

7055 aluminum alloy reinforced with 15wt. % TiB2 particulates was synthesized by in situ method, the microstructure and tensile properties were investigated. There are a few particulate clusters in the matrix. The elastic modulus and hardness of the composite are higher than that of the matrix alloy, but the yield strength and ultimate tensile strength decrease. The decrease of strength is attributed to the presence of TiB2 particulate cluster and residual reaction slag.
Direct Synthesis and Characterization of Three-Dimensional Graphene Foam
Authors: Huang Wen Bin , Wang Guang Long , Gao Feng Qi , Qiao Zhong Tao , Wang Gang , Tao Li
Published: November 2013

Three-dimensional graphene foam (GF) is synthesized by chemical vapor deposition (CVD) at ~1000°C under ambient pressure. Then it is characterized by scanning electron microscopy (SEM) and laser Raman spectroscopy, the results indicate that GF has changed the surface morphology of Ni foam, and ~ 98% of the GF are fewlayer. At last, the surface wettability of GF is investigated, which shows that it is hydrophobic. The special three-dimensional structure and excellent properties of GF make it a candidate for a range of applications.
The Synthesis of a Polyaspartic Acid Ester and Development of the Coatings
Authors: Liu Xiao Ping , Zheng Tian Liang
Published: November 2013

A new type of polyaspartic acid ester (PAE) was synthesized by double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) via a Michael addition reaction. The Fourier transform infrared spectrometer shows the reaction can take place in room temperature. The dynamics of the reaction were investigated by mercaptan-iodine titration analysis method at 57°C and 67°C. The results showed the reaction order between double alkyl malay acid ester and bis-(p-aminocyclohexy) methane (PACM) was three. The solvent free polyaspartic polyurea coating was developed with the synthesized resin and the properties were tested with good results.
Fatigue Crack Prediction of LC9 with Corrosion Damage Considering Effect of Load Frequency
Authors: Li Xu Dong , Mu Zhi Tao , Sun Wen Sheng
Published: November 2013

Considering the degradation effect of corrosion damage on fatigue behavior of aero aluminum alloy, the present thesis made a research on corrosion fatigue crack growth rate. Taking into account the effect of load frequency on fatigue crack growth, a concept of corrosion fatigue frequency factor is proposed. Based on the fact that low frequency will lead to high corrosion fatigue crack growth rate, and frequency higher enough will make little difference between corrosion fatigue and pure mechanical fatigue behavior, an exponential expression of corrosion fatigue frequency factor is proposed. The crack growth rate prediction from proposed formula is proved to be in good agreement with experimental results for steadily extended corrosion fatigue crack.
Improve Efficiency of Organic Solar Cell by Adding Dispersed ZnO Nanoparticles
Authors: Lu Yang Ming , Wu Yu Fan , Hsu Lien Chung
Published: November 2013

The poly (3-hexylthiophene) (P3HT) is a promising candidate material for using in polymer solar cells researches due to its good absorbance and stability. In this study, we present the electro-optical performance of organic polymer solar cells based on P3HT: [6,-phenyl-C61-butyric acid methyl ester (PCBM) with weight ratio of 1:1. We added ZnO nanoparticles into the blending of P3HT and PCBM to improve the performance of polymer solar cells. ZnO nanoparticles are very promising inorganic metal oxides for use in organic solar cells because of its low cost, nontoxicity, high reflectance and good electron transport properties. The morphology of polymer solar cell was improved due to the additional of ZnO nanoparticles. The effects of thermal annealing on the solar cell had been studied. The post-annealing shows significant improvement in the performance for solar cell. How to prevent ZnO nanoparticles to agglomerate is essential as they are added to the active layer of the solar cell. Well dispersed ZnO nanoparticles are obtained by using the methanol solvent. The best performances of the solar cell with short-circuit current density of 14.66 mW/cm2 and efficiency of 3.92% can be obtained after post-annealed with well being dispersed 1.3wt% ZnO nanoparticles in the active layer.
Elastic-Plastic State of Inhomogeneous Soil Array with a Spherical Cavity
Authors: Andreev Vladimir I. , Avershyev Anatoliy S. , Jemiolo Stanislaw
Published: November 2013

The article deals with the elastic-plastic state of inhomogeneous array with a spherical cavity. Model is used thick-walled ball of an elastic-perfectly plastic material (Prandtl diagram). It is shown that in the inhomogeneous material, depending on the inhomogeneity functions describing the change of the modulus of elasticity and yield stress of soil plastic deformation may appear on both the inner and outer surface of the ball and inside it. Are found values of the limit loads, displacement diagrams are constructed in an array.
Method of Tool Path Optimization in Impeller NC Machining Based on Configuration Space Theory
Authors: Geng Ren Xian , Qi Hou Jun
Published: November 2013

The impeller as the key part of aircraft engine components, and the impeller blade surface is complex, and it is a typical complex difficult machining parts. Five-axis NC machining is the important means to realize sculptured curved surface parts machined with high quality and efficiency. In this paper, in view of the interference problems occurred in the process of impeller five-axis NC machining tool path generating, the configuration space method is proposed to tackle the problem of interference, cutter location point as constraint conditions, the cutter position is described by using two angle parameters, optimization of cutter position, tool path generated without interference, improve the impeller machining quality and production efficiency. Finally, as a case study of a certain type of impeller, it makes arithmetic realization combining with MATLAB.
Study on Data Compression Algorithm Based on Semantic Analysis
Authors: Hong Qi , Lu Xiao Lei
Published: November 2013

As a lossless data compression coding, Huffman coding is widely used in text compression. Nevertheless, the traditional approach has some deficiencies. For example, same compression on all characters may overlook the particularity of keywords and special statements as well as the regularity of some statements. In terms of this situation, a new data compression algorithm based on semantic analysis is proposed in this paper. The new kind of method, which takes C language keywords as the basic element, is created for solving the text compression of source files of C language. The results of experiment show that the compression ratio has been improved by 150 percent roughly in this way. This method can be promoted to apply to text compression of the constrained-language.
Mixing Methods Influencing on Properties of Epoxidized Natural Rubber/Polypropylene Thermoplastic Vulcanizates
Authors: Hayichelaeh Chesidi , Nakason Charoen , Thitithammawong Anoma
Published: November 2013

Epoxidized natural rubber (ENR)/Polypropylene (PP) thermoplastic vulcanizates were prepared by melt mixing method in an internal mixer. Influences of different mixing methods for incorporation of processing oil into the TPVs on tensile and dynamic mechanical properties of the TPVs and crystallinity of the PP were investigated. Results show that distribution of processing oil in the ENR/PP TPV is important due to the processing oil can promote and in the same time can interrupt an improvement in elastomeric properties of the TPV. Incorporation of processing oil into the ENR phase by preparation of oil extended ENR (the mixing method 1) before mixing with the PP was the better way to produce the TPV. It promoted the TPV with superior tensile and dynamic mechanical properties than the TPVs prepared from the mixing method 2 and 3 in which the processing oil was directly added into the PP phase. Furthermore, the TPV from the mixing method 1 had less effect of processing oil on the PP crystallization.
Study of Rheological Behavior and Extrudate Surface Quality of Rubber Compounds
Authors: Prateeprat Poonyawat , Suchiva Krisda , Sirisinha Chakrit
Published: November 2013

Protocol of capillary test for a characterization of rheological properties in various rubber compounds was implemented. By the use of capillary die specially designed by Michelin, the surface characteristics of the extrudate of various rubber compounds were investigated. Parameters investigated were: types of rubber matrix (NR, BR and SBR), loadings of carbon black and types of processing aids. The Index of Cohesion (IC), gained from the analysis of the extrudate surface severity, was used for predicting the cohesive force within the rubber molecules. The high IC value implied low magnitude of extrudate surface severity, i.e., high melt strength of the rubber compounds. Also, the investigation on extrudate surface appearance yielded the information on flow regimes, i.e., smooth surface, sharkskin instability and gross melt fracture. Furthermore, the extrudate surface quality was determined by the use of the rubber extruder equipped with the Garvey die as a standard tool for evaluating the extrudability of unvulcanized rubber compounds. The interconnection between IC value and Garvey die extrudability of rubber compounds was established. Result obtained revealed significant difference in extrudate surface characteristics of rubber compounds with different types and loadings of carbon black and processing aids. The SBR extrudates showed smooth extrudate surfaces whereas the BR extrudates exhibited sharkskin instability at any given output rate. Moreover, with increasing the black content, the SBR compounds showed the increment of the IC value meaning the reduction in magnitude of extrudate surface severity.
An Investigation onto Polydimethylsiloxane (PDMS) Printing Plate of Multiple Functional Solid Line by Flexographic
Authors: Maksud M.I. , Yusof Mohd Sallehuddin , Jamil M. Mahadi Abdul
Published: November 2013

Recently low cost production is vital to produce printed electronics by roll to roll manufacturing printing process like a flexographic. Flexographic has a high speed technique which commonly used for printing onto large area flexible substrates. However, the minimum feature sizes achieved with roll to roll printing processes, such as flexographic is in the range of fifty microns. The main contribution of this limitation is photopolymer flexographic plate unable to be produced finer micron range due to film that made by Laser Ablation Mask (LAMs) technology not sufficiently robust and consequently at micron ranges line will not be formed on the printing plate. Hence, polydimethylsiloxane (PDMS) is used instead of photopolymer. Printing trial had been conducted and multiple solid lines successfully printed for below fifty microns line width with no interference between two adjacent lines of the printed images.
Effect of N-Phenyl-p-Phenylenediamine Modified Vegetable Oils on Properties of ENR/PP Thermoplastic Vulcanizates: A Comparative Study
Authors: Hayichelaeh Chesidi , Wangwon Watcharawoot , Nakason Charoen , Thitithammawong Anoma
Published: November 2013

This research focuses on feasibility study of using n-phenyl-p-phenylenediamine modified vegetable oils as processing oil in the blend formulation of epoxidized natural rubber (ENR) /polypropylene (PP) thermoplastic vulcanizates (TPVs). Effect of n-phenyl-p-phenylene-diamine modified vegetable oils on tensile and dynamic mechanical properties of the ENR/PP TPVs was investigated. For a comparison purpose, vegetable oils, epoxidized vegetable oils, and white oil were selected and also used in our experiment. Results show that all types of oils used in this study did not give the TPVs with significantly different values of tensile strength. The TPVs with petrochemical based white oil obviously provided the best elongation at break and tension set. However, by using n-phenyl-p-phenylenediamine modified palm oil (pA-m-EPO) the ENR/PP TPVs showed superior elastomeric properties (higher storage modulus together with lower tension set, tan δ and complex viscosity) than those of other TPVs. This means that the pA-m-EPO performed good compatibility with the TPV and had good distribution in the ENR molecules.
Highly Glycerin-Loaded Natural Rubber Films Prepared by Casting Technique Using Different Solvents
Authors: Issarayungyuen Pongsathorn , Pichayakorn Wiwat , Phaechamud Thawatchai
Published: November 2013

The highly glycerin-loaded natural rubber (NR) films were fabricated by casting technique with different solvents including dichloromethane (DCM), diethyl ether and tetrahydrofuran (THF) with an addition of 75 phr glycerin. Their mechanical properties, wettability and topography were determined. The highly glycerin-loaded NR films exhibited the continuous porous structure which their tensile strength values decreased whereas their wettability was enhanced. Pore size of the glycerin-loaded NR films prepared by using DCM as a solvent was greatly larger than those of the systems prepared by using diethyl ether and THF, respectively. Some active compounds might be loaded into these modified porous structures of NR films and applied for controlled drug delivery systems.
Influence of Benzyl Ester Oil on Processability of Silica Filled NR Compound
Authors: Boontawee Hasleena , Nakason Charoen , Kaesaman Azizon , Thitithammawong Anoma , Chewchanwuttiwong Sopa
Published: November 2013

Modified benzyl esters from coconut, palm, and soybean oil were used as alternative rubber processing oil to replace distillate aromatic extract oil (DAE). The effect of benzyl esters on mixing, curing properties, polymerfiller interaction and Mooney viscosity was investigated in silica filled natural rubber compound. Benzyl ester oil was found to be effective processing oil with decreasing of mixing energy and Mooney viscosity. Furthermore, it was found that coconut and palm benzyl esters showed higher torque difference than the aromatic oil filled compound. Also, benzyl ester oil gave similar level of cure time and dynamic properties compared with the rubber compound with aromatic oils.
The Effect of Process Factors to the Kinetic Studies of Emulsion Copolymerization of Natural Rubber and Styrene
Authors: Jaimuang Santi , Vatanatham Terdthai , Limtrakul Sunan , Prapainainar Paweena
Published: November 2013

Graft copolymer of styrene on natural rubber was prepared in laboratory by emulsion polymerization using potassium persulfate and sodium laurysulfate as an initiator and an emulsifier, respectively. The concentrations of initiator and emulsifier were varied in the range of 0.7 to 2.0 parts and 5.0 to 11.0 part per 100 parts of organic compositions, respectively. The gross polymers were purified by soxhlet extraction to remove ungrafted polystyrene and ungrafted natural rubber to obtain the graft copolymer (NR-g-PS). Characterization of graft copolymer was confirmed by FTIR spectroscopy. The results of the conversion, the kinetic rate of polymerization and grafting efficiency as a function of initiator and emulsifier concentration were studied. It was found that the conversion and the rate of polymerization increased with initiator and emulsifier concentration. At 1.0 parts of initiator and 5.0 parts of emulsifier were the optimum values. Therefore, the conversion and grafting efficiency can be used to predict the reaction conditions as a guideline for the graft copolymer production in pre-scale up reactor.
Reduction of Cost Employing Lean Supply Chain in Rubber Glove Industry
Authors: Hongpiriyakul Sukonthip , Sirivongpaisal Nikorn , Suthummanon Sakesun , Kongkaew Wanatchapong , Penchamrat Pallapat
Published: November 2013

Rubber glove industry in the supply chain has become increasingly important because of the significant change in consumer behaviors, which turn to focus on healthcare and disease protection. Thailand is among the leading exporting countries of rubber glove. Under current situation, with high labor cost and energy cost having an impact on production cost, the need for cost reduction in the industry is extremely of concern. This research demonstrates application of the lean supply chain for cost reduction in the industry. The aim is to lower the total supply chain cost by reducing the lead time. Value stream mapping is employed to analyze non valued activities (wastes) in the supply chain. Propositions for eliminating the wastes are presented.
Removal of NH3 in Air Released from Rubber Latex Process Using Skim Serum Absorbent
Authors: Pansang Siranat , Kasikamphaiboon Preecha , Chungsiriporn Juntima
Published: November 2013

The treatment of NH3 releasing concentrated rubber latex to air was studied using skim serum in laboratory scale of bubble absorption reactor. The skim serum (pH 2.5 to 3) is a liquid waste from concentrated rubber latex. The concentration of NH3 in air (300 to 1500 ppmv) and air flow rate (0.5 to 1.5 l/min) feeding into the reactor were measured for the effect of the treatment efficiency. At lower NH3 concentration and air flow rate have resulted to higher NH3 removal efficiency. Bubble absorption reactor can be effectively used and applied to remove NH3 releasing from the concentrated rubber latex process to the air without any plugging of the skim rubber in the system. Skim serum waste liquid has the result in higher efficiency in NH3 removal comparing to pure water usage. This study would be practically used as a guidance for the further design and operate to minimize waste and emission control in rubber industrial-scale system.
Heat Built-Up of Industrial Solid Tires in Thailand
Authors: Rukkur Sanae , Dechwayukul Charoenyut , Thongruang Wiriya , Patarapaiboolchai Orasa
Published: November 2013

Solid tires made of natural rubber, manufactured and used for forklift trucks in Thailand, have quality problems involving blow out [. Failure of solid tires may occur from excessive loads and or heat generation inducing loss of mechanical properties. The failure of solid tires relating to heat generation is considered. Solid tires under severe conditions, such as overloading, high speed, or high temperature work places often leading to fail and blowout. When these are continuously rolled and loaded, the rubber is stressed and deformed leading to heat generation [. The hysteresis loss storage in form of strain energy due to internal friction in the rubber converts to the heat source transfer to the section of tire. During carrying heavy load, solid tire is subjected to the repeat compressed cyclic loading. Since rubber has the visco-hyperelastic property, cyclic load deformation causes hysteresis loop when tire is performed under cyclic load. Hysteresis loops area indicates the amount of energy turn into heat and it is difficult transferring to the surface of the tire due to insulation itself. As the results, there is heat build-up as shown in term of temperature rising differs in each tire and finally causes blowout or explosion.
Current Study on Structural Characterization and Unique Film Formation of Hevea brasiliensis Natural Rubber Latex
Authors: Sakdapipanich Jitladda
Published: November 2013

Hevea brasiliensis natural rubber (NR) latex is a very important commercial source of elastomers. It is not only a source for dry NR rubber but also the feedstock for the latex glove dipping industry. The particles of freshly tapped latex are known to be stabilized by proteins and lipids that come with the latex from the tree. These non-rubbers [, especially proteins and lipids, confer to the rubber and latex excellent properties unsurpassed by any synthetic latex [. Recent structural studies of NR revealed that the NR molecules comprise of 2 trans-isoprene units connected to a long-chain cis-isoprene units. Two terminal groups, referred to as ω and α, have been postulated to link with mono-and di-phosphate groups associated with phospholipids by H-bonding at the α-terminal, whereas the ω-terminal is a dimethylallyl group links to protein by H-bonding [. Although numerous studies have been published on the surface structure of the natural rubber particle [4-, none of these offered a direct in situ visualization of the intact particle surface. This is because of any attempt to remove this surface layer of proteins and lipids results in an immediate destabilization of the latex. The second part focused on the using of Atomic Force Microscopy (AFM) and Confocal Fluorescence microscopy to visualize and delineate the structure of the proteins and lipids layer on the latex particle surface in situ.
Thermal and Mechanical Properties of Natural Rubber/Rice Starch Interpenetrating Network Hydrogel
Authors: Sila-On Warisada , Pratoomted Jatuporn , Puapermpoonsiri Utsana , Vudjung Chaiwute , Pichayakorn Wiwat
Published: November 2013

Novel hydrogels based on natural rubber latex (NRL) and rice starch (RSt) (1:2 ratio) were prepared with various amount of N,N-methylenebisacrylamide (MBA) and 2.5 phr of maleic acid to form interpenetrating networks (IPN) using free-radical polymerization technique. The thermal and mechanical properties were performed by differential scanning calorimetry and mechanical tests. From data obtained, the change in Tg of rubber and melting point of RSt indicated that polymer-polymer interaction could be formed in IPN hydrogel. The higher amount addition of MBA created more mechanical strength of IPN hydrogels caused by the higher of interlacement formation. However, their mechanical strength of such hydrogels was lower than that of NRL alone due to the formation of amorphous structure in IPN hydrogel. These IPN hydrogels also improved the swelling property which will be utilized for wound healing application.
In Situ X-Ray Diffraction Study of Phase Development during Hardening of β-Tricalcium Phosphate Bone Cements with Chitosan
Authors: Tonoli Marina Salvarani , Beppu Marisa Masumi
Published: November 2013

The aim of this work was to study the phase transformation during the setting reaction of beta tricalcium phosphate (β-TCP) and phosphoric acid with chitosan solution added. To follow the kinetics of the phase transformation, two methods were used: x-ray diffraction (XRD) was used to study the phase evolution during the hardening process in real time, and was also used in samples where the reaction was supposedly stopped in different times using acetone, as indicated in literature. The setting reaction occurs so fast that the phase transformation could not be observed, but it was possible to invalidate the second mentioned method for this system, as it induces the final product dicalcium phosphate dihydrate DCPD (brushite) to be converted into his anhydrous form dicalcium phosphate DCP (monetite). The addition of chitosan in order to improve biocompatibility was successfully done, it could be observed that chitosan inhibits brushite crystallization in the first moment of the reaction, but the final product was not affected by it.
Influence of Nanograin Size ZrO2 and Al2O3 Ceramics on Biological Response of Cells
Authors: Matoušek Aleš , Kukletová Martina , Cihlář Jaroslav
Published: November 2013

The influence of the grain size of alumina and zirconia ceramics on the spreading and adhesion of MG63 cell lines was investigated. Single-component ceramics and layered composite ceramics were prepared by electrophoretic deposition, uniaxial pressing and sintering. The grain size of zirconia was 100 nm to 2.7 μm and that of alumina was 0.5 μm to 1.5 μm. Subsequently, sample surfaces were polished and thermally etched. Biological tests of adhesion (0.5 to 8 h) were used to evaluate the influence of grain size on biological response. The highest cell spreading was obtained for ZrO2 ceramics with an average grain size of 100 and 120 nm. The cell selection was observed on layered ZrO2/Al2O3 composites. The cells predominantly adhered to ZrO2 layers. The results showed a positive influence of nanostructured ceramic surfaces on biological behaviour of MG63 cells.
Novel Bioactive Materials neither Based on Calcium Phosphate Nor Silicate: Titanium Oxide
Authors: Kokubo Tadashi
Published: November 2013

Various kinds of materials have been found to bond to living bone and some of them are clinically used as important bone substitutes. However, they can not be used under load-bearing conditions, since their fracture toughness are not so high as that of human cortical bone. All of them are based on calcium phosphate or silicate. The present authors recently showed that even Ti metal and its alloys having high fracture toughness can show bone-bonding bioactivity, if they are subjected to simple chemical and heat treatments to form some kind of titanium oxide or titanates on their surfaces. They can show not only bone-bonding property, but also novel functions such as osteoinduction, release of antibacterial or bone-growth promoting ions etc.
Production and Mechanical Properties of Commercial Synthetic Hydroxyapatite (CSHA) Composites
Authors: Demirkol N. , Oktar F.N. , Kayali E.S.
Published: November 2013

Hydroxyapatite (HA), one of the calcium phosphate compounds, is the most widely used bioceramic. HA materials have a common usage in bone repairing due to its ability to accelerate the bone growth around the implant. HA is a biocompatible material and used in production of various kinds of prosthesis, repairing the cracked or broken bones and coating of metallic biomaterials. This study covers production and characterization of composite materials made of commercial synthetic hydroxyapatite (CSHA) with commercial inert glass, magnesium oxide and niobium (V) oxide additions (5 and 10 wt%), seperately. These additives used as reinforcement materials to improve the mechanical properties of CSHA based composites. The composites were subjected to sintering at different temperatures between 1000oC and 1300oC, then microstructures and mechanical properties of CSHA composites were investigated. The physical and mechanical properties were determined by measuring density, compression strength and Vickers microhardness (HV). Structural characterization was carried out with X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies. In all composites, density values and mechanical properties increased with increasing sintering temperature. CSHA composite with 5 wt% CIG addition showed highest physical and mechanical properties among all CSHA composites produced in this study.
Nanoparticles for Biomedical Applications Prepared by CO2 Laser Vaporization
Authors: Müller Frank A. , Kurland Heinz Dieter , Grabow Janet
Published: November 2013

Functional ceramic nanopowders with emphasis on biomedical applications were engineered by gas-phase condensation using the CO2 laser vaporization (LAVA) technique. Europium doped strontium aluminate nanoparticles (NP) were prepared from a SrO/α-Al2O3/Eu2O3 powder mixture. Excited with ultraviolet radiation (UV), the as-prepared amorphous NP revealed red photoluminescence emission. After annealing in reductive atmosphere crystalline SrAl2O4:Eu2+ nanopowder was obtained showing strong green emission at UV excitation. Ferrimagnetic iron oxide (FexOy) nanopowders were prepared starting from α-Fe2O3 powder. In oxygen-free condensation atmosphere γ-Fe2O3 NP were obtained. Oxygen as condensation gas yielded γ-and ε-Fe2O3 NP. Superparamagnetic NP were prepared starting from α-Fe2O3/SiO2 mixtures. Depending on the mixing ratio γ-Fe2O3 nanocrystallites embedded in a SiO2 glass matrix or γ-Fe2O3-SiO2 Janus NP were obtained. These NP provide a reactive SiO2 interface for subsequent functionalizing. The co-vaporization of α-Al2O3 as the main proportion and t-ZrO2 yielded zirconia-toughened-alumina NP. Reinforcing effects of Al2O3-ZrO2 dispersion ceramics will be increased using NP with an intraparticle dispersion of these phases. Future applications of the LAVA prepared NP include biological fluorescence labeling, and drug targeting, magnetic resonance imaging, and hyperthermic cancer therapy, as well as sintering of load bearing ceramic implants, respectively.
Fabrication of Magnetic Hydroxyapatite Microcapsule for Protein Collection
Authors: Kumazawa Shun , Hisashuku Daiki , Yabutsuka Takeshi , Yao Takeshi
Published: November 2013

When pH or temperature of simulated body fluid (SBF) is raised, fine particles of calcium phosphate are precipitated. We found that this fine particle actively induces hydroxyapatite from body fluid or SBF and named the particle Apatite Nucleus (AN). In this study, we attached AN on the surface of γ-Fe2O3 nanoparticles and soaked them in SBF. By this treatment, hydroxyapatite was induced from AN and covered the whole surface of the γ-Fe2O3 nanoparticles, then hydroxyapatite microcapsule encapsulated γ-Fe2O3 was fabricated. We dispersed the microcapsules in urease solution, and collected the microcapsules by neodymium magnet. It was indicated that the urease was adsorbed to the hydroxyapatite microcapsules and collected by the magnetism of γ-Fe2O3 successfully.
Fabrication of Bioactive Apatite Nuclei Precipitated Polylactic Acid by Using Sandblasting Process
Authors: Yabutsuka Takeshi , Mizuno Hiroshi , Yao Takeshi
Published: November 2013

Micropores were formed on the surface of polylactic acid (PLA) plate by doubled sandblasting process using alumina particles with 14.0 μm for average particle size as first process, then using the particles with 3.0 μm for average particle size as second process. Apatite Nucleus (AN) was precipitated in the pores. By these treatments, bioactive AN precipitated PLA was fabricated. Bioactivity of the AN precipitated PLA was examined by soaking in SBF and it was observed that hydroxyapatite was induced on the surface of the PLA within 1 d. High adhesive strength of hydroxyapatite layer was achieved due to a mechanical interlocking effect between hydroxyapatite formed in the micropores and the PLA plate.