bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery of Metal Values from Low-Grade Heterogenite with Reductive Ammonia Leaching Method
Authors: Yang Bin , Fan Min Guang , Li Lin Yan , Li Bin , Xu Sheng Ming , Wang Xue Jun , Liu Xin
Published: March 2014

Reductive ammonia leaching method was used to recover Cu and Co from heterogenite. The influences of the reductant quantity, leaching temperature, the concentration ratio of NH3to (NH4)2SO4, leaching time and liquid-solid (L/S) ratio on leaching rate of cobalt and copper were investigated. The optimal conditions at which the leaching rate of copper and cobalt were 96.07%, 98.24% respectively and that of Fe, Mg and Al were almost 0 were as follows: time = 5 h, T = 50°C, the amount of ammonia is 1.2 times of theorrtical, C(NH3):C [(NH4)2SO4] =1:3, L/S ratio = 3:1, and the dosage of Na2SO3is 0.5 times of the heterogenites mass.
Mechanical Property for the Combining Yarn of BF/GF and Polypropylene
Authors: Liu Shuang Shuang , Tian Wei , Zhu Cheng Yan
Published: March 2014

In order to study the mechanical property for the combining yarn of BF/GF and polypropylene, 8 groups of combining yarn were designed and prepared. Through testing the mechanical property of the yarns, the affection of some parameters on the property of the yarns was analyzed. And following conclusions can be gotten. For BF/polypropylene combining yarn, when the fiber content of basalt is about 50.7%, the mechanical property of the yarn is the best. When the fiber content of basalt is about 43.7%, the mechanical property of the yarn is the worst. For GF/polypropylene combining yarn, the optimal and worst ratio is 55.42% and 44.4%, respectively.
Selection and Evaluation of Potential Probiotic Lactic Acid Bacteria and Bifidobacteria Isolated from Human Intestinal Tract
Authors: Xue Chao Hui , Zhang Lan Wei , Li Hong Bo , Wang Shu Mei
Published: March 2014

Three Lactobacillus strains were screened on the basis of probiotic characteristics (i.e., resistance to low pH and bile salts, adhesion to the human gastrointestinal tract, inhibition of pathogenic strains). They further exhibited producing antimicrobial activities of non-acid molecule (s). In addition, antibacterial peptides were isolated and purified from the cell-free culture supernatants of these three probiotic strains. Based on TricineSDSPAGE, the antimicrobial peptide was approximately 10 kDa in size. After analyzing the sequence of the 16SrDNA regions of these three strains, they were identified asLactobacillus crispatus Lactobacillus rhamnosus and Lactobacillus rhamnosua GG.Using an in vitro system simulating gastric transit, our findings indicated that the three probiotic strains had the ability to tolerate gastroenteric environment and the adhesive capacity to HT-29 cells. It was demonstrated that the probiotic strains inhibited subsequent adhesion of E. coli to the HT-29 cell. Among the selected strains,L. rhamnosusF1333 showed a high probiotic potential and could be used in health-promoting food products.
Manufacturing Technique and Property Evaluations of Sandwich-Structured Nonwoven Composites
Authors: Lou Ching Wen , Lu Po Ching , Shih Ying Huei , Yeh Hsuan Mao , Lin Jia Horng
Published: March 2014

This study aims to examine the thickness of a sandwich structure and the lamination number of the Kevlar nonwoven fabrics o n the punch resistance strength and impact resistance strength of the nonwoven composites. Kevlar nonwoven fabrics and Nylon/low-melting-point polyethylene terephthalate (LPET) nonwoven fabrics are laminated with various combinations to form sandwich-structured nonwoven composites. The experiment results show that an increasing number of Kevlar nonwoven fabrics results in low dynamic and constant rate puncture resistance but high impact strength; and conversely, an increasing thickness of sandwich-structured nonwoven composites causes high dynamic and constant rate puncture resistances but low impact strength.
Preparation and Property Evaluations of Polyvinyl Alcohol (PVA)/Graphene Nanosheets (GNs) Composite Nanofibrous Mats by Using Electrospinning
Authors: Lin Jia Horng , Chiang Kun Chien , Huang Chien Lin , Lou Ching Wen
Published: March 2014

This study aims to examine the influence of graphene nanosheets (GNs) on the morphology and electrical property of polyvinyl alcohol (PVA) nanofiberous mats. GNs (0.03 %, 0.05 %, 0.1 %, and 0.3 %) are added to PVA solution, and then electrospun into PVA/GNs nanofiberous mats. A viscosity measurement and electrical conductivity measurement are performed on the samples to determine their properties. The experiment results show that when the content of GNs increases from 0.1 % to 0.3 %, the fiber diameter of PVA/GNs nanofiberous mats increases from 166 nm to 239 nm, the conductivity slightly increases, but the viscosity greatly increases. An increment in viscosity causes the beads to form complete fibers, which is in line with the outcome of scanning electron microscopic (SEM) observation.
Manufacturing Technique and Property Evaluations of Three-Dimensional Fabric/Foam Composites
Authors: Lin Jia Horng , Li Che Wei , Lou Ching Wen
Published: March 2014

In this study, two agents (a foaming agent and a hardener) are mixed to form rigid polyurethane (PU) foams with various densities, which are separately poured into a mold with a three-dimensional (3D) fabric to form 3D fabric/foam composites. The mechanical property and sound absorbency of the composites are examined. The experiment results show that an increasing density of the two-agent mixture results in a more compact PU foam, a 31 % increase in bursting strength, and a greater resilience, but also a decrease in the sound absorbency coefficient. In sum, variations in the density of the mixture have an impact on the physical properties of the fabric/foam composites, the derived results of which can thus be further applied to product designs.
Effects of Needle-Punch Depth on Properties of PET/LPET/Kevlar Nonwoven Geotextiles
Authors: Lin Jia Horng , Hsieh Jing Chzi , Li Jia Hsun , Hsing Wen Hao , Lou Ching Wen
Published: March 2014

Geotextile has been commonly used in civil and geotechnical engineering applications, and the majority of geotextiles is made of nonwoven fabrics. Therefore, this study combines crimped polyester (PET) fibers, recycled Kevlar unidirectional selvage fibers, and low-melting-point PET (LPET) fibers to form PET/Kevlar/LPET nonwoven geotextiles, and then examines how various neelde-punch depths influence mechanical properties of the resulting nonwoven geotextiles. The tensile strength, tearing strength, bursting strength, and static puncture resistance of the nonwoven fabrics increase as a result of an increase of 0.3 cm to 0.5 cm in needle-punch depth. However, an increase of 0.5 cm to 0.7 cm causes a slight decrease in all aforementioned properties.
A Cyclic Constitutive Model for Metallic Foam
Authors: Liu Yu Jie , Qiang Bin
Published: March 2014

Based on the obtained experimental results, the features of stress-strain behavior of the metallic foam were discussed firstly in this paper. Then, in the framework of 2M1C visco-plasticity constitutive model, a cyclic constitutive model was proposed to simulate the stress-strain responses under monotonic and cyclic compression. In proposed model, plastic strain is divided into two parts, i.e., plastic strain of matrix metal and plastic strain of voids structure, which are associated with relative density. Additionally, a kinematic hardening rule of yield surface center is used to describe ratchetting effect during cyclic loading. The simulated stress-strain responses of aluminum foam are in a good agreement with the experimental ones.
Applied Mechanics and Applied Technology in Fuel Injection Pump Bench Rotational Speed Measurement System Design Based on CPLD
Authors: Wang Ji Chang , Quan Huan Huan
Published: March 2014

In the article, proposing one kind of design plan about rotational speed measurement system design based CPLD. Various modules design has completed according to EDA tools and VHDL hardware description language. The feasibility of the speed measurement system design was verified based on the experiment. At present, the system has been successfully application in the fuel injection pump test-bed.
Research on Mechanical Mechanics with the Finite Element Analysis and Structure Optimization of Large Span Gantry Crane Box Beam
Authors: Hu Shi Cheng , Liu Bin , Wang Xiang Jun , Zhang Wei You
Published: March 2014

Large span gantry crane girder structure has a direct effect on the performance of the whole machine. This paper,by using ANSYS, gets the distribution of the stress and deformation of the box girder under different working conditions, and verifies that the box girder structure can well meet the requirements of the mechanical properties. On this basis, it establishes the objective function and constraint conditions of box girder structure, and gets the best work parameters by using Matlab to optimize the structure. The results of structure optimization can guide well in the designing and manufacturing of similar products.
Research on Manufacturing Engineering with Financial Information Management System Inter Control in Technology-Based Small and Medium-Sized Enterprises
Authors: Chen Jie
Published: March 2014

Manufacturing Engineering makes the technical science content high, if enterprise wants to utilize this kind of technical effect well .Small and medium-sized enterprises refers to the scientific and technical personnel as the main body, it is an intelligence intensive economic entity which mainly engaged in high-tech research and development, production of high-tech products and business, independent accounting. The main contents of this paper: The significance of financial information management system inter control; The specific application of financial information system under the environment of ERP; Strategies of improving the internal control of accounting information system.
Research on Information-Applied Technology with Parts Classification and Coding Based on Group Technology
Authors: Shi Ya Bei , Wang Ji Chang
Published: March 2014

Group technology is a system approach that organizes low volume production reasonably. Parts classification and coding systems are introduced mainly in this paper. And parts classification into group methods is recommended in detail. Typical parts coding and classification is described in the paper. Lastly, computer-assisted coding and classification is introduced simply.
Applied-Information Technology with Using Bayesian Belief Network for Strategy Selection of Developing Mountainous Areas
Authors: Zhu Jie
Published: March 2014

strategy selection of developing mountainous areas is an important topic in recent years, usually we believe the financial support is the most relevant factor to the development, under the condition of lack of enough money, we should first choose the best strategy which is an optimal choice for the development of economy. In this paper, we proposed to use the Bayesian belief network for the strategy selection. The optimal selection can be treated as an important guidance to consider the development of local economy.
Research on Electronic Materials with Material Properties for Multimedia Production of Transportation Service Based on MMB
Authors: An Gong , Zhang Wu Jun
Published: March 2014

MMB (Media Multimedia Builder) is an excellent multimedia production system, powerful, simple and easy to use. The characteristics of transportation service classes are required by MMB software to make the multimedia. From electronic materials with material properties for military motor transport classes, this paper analyses the characteristics of the course, points out the necessity of the courses using MMB, simply introduces the MMB interface and scripting language, analyses the key technology application MMB to make electronic materials with material properties of motor transport service classes, including text, images, video, test control, and other practical skills, should have a numerical example is given.
Threshold Voltage Adjustment for 28nm HfOx/ZrOx/HfOx Gate Dielectric of nMOSFETs Using DPN Process with Annealing Temperatures
Authors: Lee Win Der , Wang Mu Chun
Published: March 2014

Following the investigation of the relationship among the annealing temperatures for decoupled plasma nitridation (DPN) process to indirectly manipulate the amount of oxygen vacancy in high-k (HK) gate dielectric, the expected threshold voltage (Vt) of n-channel MOSFET (nMOSFET) device is able to be approached. The uniformity of Vt values related to the channel lengths was fine due to 10% deviation specification, but the roll-up phenomenon coming from the strain effect was observed. The lower annealing temperature shows the higher Vt value due to the higher interface state density, reflecting at the subthreshold swing (S.S.) characteristics.
Deep Desulfurization of Diesel Fuel Oxidized with TBHP Coupled with Solvent Extraction Intensified by Ultrasound
Authors: Yu Guo Xian , Zhong Qian , Jin Mei , Wang Jin Huang , Lu Ping
Published: March 2014

Deep desulfurization of a hydrotreated diesel fuel was investigated with TBHP oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of TBHP and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 12 ppm with using 1%wt of sodium tungstate as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 15 min and TBHP/Sulfur molar ratio of 32, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.
Experimental and Theoretical Investigation of Flexure Behavior and Failure Mode of Filament-Wound Composite Tube
Authors: Wang Jun Peng , Wang Jun , Chen Wei , Ye Yuan , Yang Xiao Li
Published: March 2014

The response of filament-wound composite tubes subjected to pure bending is studied. The decrease of D/t ratios and increase of winding angles improve the ability to resist buckling failure whereas increasing winding angle generates complex trend in material failure. The ultimate failure mode depends on the interaction of D/t ratio and winding angle. FEM results are in good agreement with experiments.
Experimental Research on Rheological Properties of Slick Water Mixed with CO2 System
Authors: Luo Xiang Rong , Wang Shu Zhong , Jing Ze Feng , Wang Zhi Guo
Published: March 2014

Rheological properties of slick water mixed with CO2 system are studied,through the large foam fracturing fluid of high temperature and high pressure experiment system,in detail in this paper, based on the principle of tube type rheometer. The influence laws temperature, foam quality, shear rate and pressure have on the rheological characteristics are studied. The fracturing fluid rheological parameters calculation correlations are also obtained, and the foam quality influence on rheological index and rheological coefficient of the slick water mixed with CO2 system are analyzed.
The Effects of Excess Calcium and Aging Media on the Mechanical Properties of Calcium Phosphate Filling Materials
Authors: Alqap A.S.F. , Sopyan Iis , Suryanto Suryanto
Published: March 2014

The effect of excess calcium and aging media on calcium phosphate biomaterials mechanical strength was studied. The variation of excess calcium and sample type has shown different performance when they are being aged in the moist environment (ME) and the simulated body fluid (SBF). The calcium phosphates were synthesized via low temperature hydrothermal method and sampled to two types of powder-water (3:2) mixture and paste for 90 days of the aging time. Two mechanical tests were applied, compression and diametrical tensile test, while XRD to evaluate phases. Scanning electron micrograph showed the paste samples that soaked in SBF was better entanglement of the particles, better compression strength but with degradation and diametrical tensile strength improvement by aging. Calcium hydroxide and ammonium di-hydrogen phosphoric was traced in all the samples along with calcium deficient hydroxyapatite as the main phase.
Intrinsic Ferroelectric Coercive Field Calculation for BZT Films Doped by Indium and Lanthanum
Authors: Hikam Muhammad , Adnan Septian Rahmat
Published: March 2014

The intrinsic coercive field is predicted by using Landau Ginzburg theory of ferroelectricity. A routine program created on Delphi platform is used to make simulation of the calculation of hysteresis loops and intrinsic coercive field. There are shifting in the values of intrinsic ferroelectric field of BZT on adding the zirconium composition, and the maximum intrinsic coercive field of BZT is found at 0.25 mol zirconium. The calculation shows that the best intrinsic coercive field is found at 1 mol % dopant.
Defect Distribution and Yield Analysis Technique on Silicon Wafer
Authors: Praepattarapisut Warakorn , Pengchan Weera , Phetchakul Toempong , Poyai Amporn
Published: March 2014

This paper presents the defect distribution and yield analysis on silicon wafer. The generation and recombination lifetime were the key parameters and obtained from the currentvoltage and the capacitancevoltage of diode characteristics for forward bias. Then 3D contour maps were plotted as defect distribution and can be analyzed for the whole wafer which is useful for the yield analysis of the defects that were caused from fabrication process.
The Influence Analysis of Stiffness on Stringer Layout and Dimension of Full Composite Wing
Authors: Qiao Sheng Jun , Gao Hang Shan , Wang Fu Sheng , Yue Zhu Feng
Published: March 2014

The present study aimed at obtaining torsional stiffness, bending stiffness and stiffness center position of full composite wing using thin wall structure mechanics theory. The influence of stringer layout on wing integer structure stiffness was furthermore investigated. It was found that wing section stiffness was influenced by stringer layout and dimension. The best spacing of stringer was within the range from 130 mm to 150 mm, at the same time, stringer stiffness had more change by the differences of its numbers. The study of this paper provided important support for structural design and aeroelastic analysis on composite wing.
Imidazolium-Based Ionic Liquid Dissolution Influence on Crystallinity of Oil Palm Frond, Oil Palm Trunk and Elephant Grass Lignocellulosic Biomass
Authors: Che Kamarludin Siti Norsyarahah , Ubong Sandra , Idris Nadzeerah , Azmi Intan Suhada , Jainal Muhammad Syafiq , Jalil Rafidah , Wan Omar Wan Siti Atikah , Zainal Mulok Tengku Elida Tengku , Safaai Nor Sharliza Mohd , Azizan Amizon
Published: March 2014

Ionic liquid (IL) has been shown to affect cellulose crystalline structure in lignocellulosic biomass (LB) during pretreatment. This research was carried out with two different experimental design involving IL to observe the effect of dissolution in IL on: (A) the crystallinity of cellulose and (B) the dissolution efficiency of LB. For experiment A, the types of IL used in this research were 1-ethyl-3-methylimidazolium Acetate [EMI[A, 1-allyl-3-methylimidazolium Chloride [AMI[C, 1-butyl-3-methylimidazolium Chloride [BMI[C and 1-ethyl-3-methylimidazolium Chloride [EMI[C. The crystallinity degree of LB was investigated before and after pretreatment with IL. The microcrystalline cellulose (MCC) was used as the simulated LB (cellulose content) was dissolved in IL and the crystallinity after the dissolution was analyzed. The temperature (70°C, 80°C, 90°C, 99°C) and concentration ratio of IL with volume/volume (v/v: 10%, 25%, 50%) were varied while the dissolution time remained constant. The crystallinity was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR). The results showed that the dissolution temperature and IL concentration ratio affects the intensity of the FTIR peaks. In experiment B, the dissolution of LB with 1-butyl-3-methylimidazolium Chloride [BMI[C and 1-Ethyl-3-methylimidazolium Chloride [EMI[C as ILs were investigated. Four types of LB involved were Elaeis guineensis species of Oil Palm Trunk (OPT) and Oil Palm Frond (OPF) and Pennisetum purpureum species (elephant grass) originated from Taiwan and India. From the results obtained, the [BMI[C gave better dissolution to biomass.
Surface Treatment of Rubber Toughened Polyester Filled Carbon Black and Kenaf Hybrid Composite
Authors: Redzuan Aein Afina Mohd , Bonnia Noor Najmi , Shuhaimen Nurul Shakirah
Published: March 2014

The influences of surface treatment on kenaf fibre for rubber toughened polyester filled carbon black (CB) and kenaf hybrid composite were investigated, in consideration for applications such as automotive parts and integrated circuits (IC) encapsulations. Kenaf fibres were divided into treated and untreated fibres, where 6% of NaOH solution was used as the treatment solution. Unsaturated polyester was mixed with 3% liquid natural rubber (LNR) as toughening agent and 4% of CB, before hybridised with both treated and untreated kenaf that were varied from 5, 10, 15, 20 and 25% using mechanical stirrer and moulded by using hot compression technique. Flexural and impact testing were conducted and it was found that the hybridisation of CB and treated kenaf fibres composite showed improvement on flexural properties compared to non-hybrid CB filled composites although there are slight decrement on impact toughness. The optimum fibre loading for both treated and untreated kenaf were found at 25%.
A Radical Rethink on Soot Containment from Auto-Rickshaw Exhausts
Authors: Ghosh S. , Shah R.N. , Goenka A.
Published: March 2014

The auto-rickshaw has become a predictable part of the everyday lives of Indian city-dwellers. Although this popular means of public transport provides relatively discounted and efficient transportation, the auto-rickshaw is a key source of soot that causes particulate air pollution. These soot emissions infringe the natural cycles of the atmosphere other than their more overt effects on human health. Consequently, their entrapment becomes vital. Though most particulate filters provide a rather good efficiency, once clogged an undesired back pressure may lead to engine and/ or filter failure. Through this study a method is proposed to overcome such impenetrability. Once the particles are confined to narrower streams, smaller filters may be used which even if clogged will allow the easy passage of the exhaust gases out of the exhaust pipe. The most immediate outcome of this research is that the CFD simulations suggest inexpensive design alterations in the diesel particulate filter which can be fabricated easily. With government subsidies this component can be mass manufactured for use in India and other Asian countries where auto-rickshaws are widely used.
Potential Utilization of Catalyst for the Combustion of Wood in Households
Authors: Krpec Kamil , Horák Jiří , Martiník Lubomír , Kubesa Petr , Hopan František , Kysučan Zdeněk , Kremer Jiří , Jankovská Zuzana
Published: March 2014

The application of stricter requirements on combustion devices is placing more pressure especially on the manufacturers of such devices. They can improve the emission parameters of their products e.g. by primary technical measures (modification of combustion air supply, modification of combustion chamber, introduction of a final combustion chamber, etc.) or by secondary technical measures, e.g. introduction of a catalyst into the exhaust route.
Enhanced Thermal Stability and Flame Retardancy of a Novel Transparent Poly(Methyl Methacrylate)-Based Copolymer
Authors: Jiang Sai Hua , Lo Siu Ming , Hu Yuan
Published: March 2014

A novel poly (methyl methacrylate) (PMMA) based copolymer was synthesized by bulk copolymerization of methyl methacrylate (MMA) and a phosphorus-containing monomer, acryloxyethyl phenoxy phosphorodiethyl amidate (AEPPA). The chemical structure of AEPPA was confirmed by FTIR, 1H NMR and 31P NMR. The structure of copolymers was characterized using FTIR. TGA results indicate that the thermal stability of copolymers was remarkably enhanced with the addition of APEEA. LOI and MCC results suggest that the flame retardancy of copolymers was also improved. Detailed flame-retardant mechanism is proposed. The char formation during degradation caused by APEEA plays a key role in the property improvements.
Effect of Coarse Aggregate Sizes on Properties of Porous Concrete Paving Blocks
Authors: Nur Hidayah A.H. , Hasanan Md Nor , Ramadhansyah P.J.
Published: March 2014

Properties of Porous Concrete Paving Blocks (PCPB) were investigated in this study. Two groups of coarse aggregate sizes were performed; passing 8 mm retains 5 mm and passing 10 mm retains 8 mm. For mixture design, 100 % of coarse aggregate were used. However, fine aggregate was eliminated in this investigation. The density, water absorption, flakiness index and elongation index test were performed to determine the properties of the coarse aggregate used in this study. Compression test and skid resistance test were used to evaluate the performance of PCPB. The results show that PCPB containing coarse aggregate size 5 8 mm give high compressive strength compared to others PCPB specimen. In addition, both PCPB specimens give an in increasing in skid resistance approximately 30 % compared to Concrete Paving Blocks (CPB).
Synthesized Hydroxyapatite Powder from Clamshell via Chemical Precipitation Method
Authors: Nurul Huda Ali , Subuki Istikamah , Hussain Ismail Muhammad
Published: March 2014

Hydroxyapatite (HAp) is a kind of bioceramic based material that has been used extensively in many medical applications. Owing to nearly similar mineral contents to natural bone, the material has been accepted as an implant in order to improve the osteointegration with the bone tissue. In this work, an alternative processing route from waste materials, namely clamshell in producing HAp powder is presented. The effects of processing temperatures, ranging from 750°C to 950°C and pH values, ranging from 6.5 to 8.5 on the synthesized HAp prepared via chemical precipitation method were investigated. From the XRD, FTIR and EDX results, it was observed that the lowest pH value of 6.5 with the temperature of 850°C is the optimum parameters to synthesize HAp.
Properties of Epoxy/Carbon Black/Graphite Composites for Bipolar Plate in Polymer Electrolyte Membrane Fuel Cell
Authors: Suherman H. , Sahari J. , Sulong A.B. , Astuti S. , Septe E.
Published: March 2014

Epoxy resin (EP) composites including carbon black (CB) and graphite (G) were produced and investigate. The in-plane electrical conductivity of EP/CB/G composites was measured. Various weight percentages (wt.%) of CB as a secondary filler and G as a primary filler were added into the EP as a matrix. Dispersion of CB and G within matrix were conducted by an internal mixer (Haake Reomix). Mixture of EP/CB/G was poured into the steel mold, and produced through hot press machine. In-plane electrical conductivity of EP/CB/G composites in terms of variation of CB and G concentration were measured by the Jandel multi high four point probe. The highest in-plane electrical conductivity of the EP/CB/G composites obtained was 120 S/cm. This value exceeds the requirement of U.S Department of Energy (DOE) target for bipolar plate application (> 100 S/cm).
Comparative In Vivo Study of Biocompatibility of Apatites Incorporated with 1% Zinc or Lead Ions versus Stoichiometric Hydroxyapatite
Authors: Giorno Bruno , Castro-Silva Igor Iuco , Malta Rossi Alexandre , Granjeiro José Mauro
Published: March 2014

Hydroxyapatite is the main ceramic material that has being used in bone repair, although its physico-chemical and in vivo behavior should be better understood. A method to improve the biocompatibility of HA is the substitution of calcium with divalent cations which enhance mechanic resistance and can modulate inflammatory response against implanted material. In this study we analyzed the biocompatibility of HA doped with one per cent of Zn2+ or Pb2+. The first one has being described as an inflammation modulator and the second would be a model for chronic toxicity assay. Biocompatibility of the both materials was studied in vivo following the ISO 10993-6 standard. HA cylinders (ZnHA, PbHA and stoichiometric HA as positive control) were implanted into subcutaneous tissue of 45 Balb-c mice and after 1, 3 and 9 weeks the animals were euthanized (5 for each experimental condition). Necropsies of the skin containing reactional tissue were removed, fixed in 10% formaldehyde and followed the histological processing for paraffin embedding and staining with Hematoxylin-Eosine and Picrosirius red. Microscopic analysis showed for all groups moderate inflammatory response, decreasing throughout the experimental periods, with ZnHA group showing more intense response. Similar presence of macrophages, fibrosis and angiogenesis were observed among the groups. Thereby, we can conclude that ZnHA and PbHA are biocompatible and not bioresorbable, being the ZnHA potentially indicated as bone graft. Detailed studies are required to better understand the role of PbHA as chronic model for lead toxicity.
Study of Electrospun Chitosan Nanofibrous Coated Webs
Authors: Sinha Mukesh Kumar , Das Biswa Ranjan , Srivastava Anurag , Saxena Arvind Kumar
Published: March 2014

Fabricated nanowebs are successfully coated with polypropylene spun bonded non-woven fabric with various coating density ranges from 0.25-1.2 gsm. This study describes an electrospinning coating process of pure Chitosan dissolved in TFA and DCM and its detailed characterizations. The optimal solution condition for electrospinning was studied and, thereby, the process was successfully established. The best optimal condition: 11 % Chitosan was successfully electrospun (superlative web structure) in the electric field of 75 KV, distance between spinning electrodes 135 mm and rotation of spinning electrode 5 rpm (throughput). Once it was determined the ideal condition for fabricating web thereafter under identical conditions electro coating process was done by varying collector speed. The resultant nanofibrous web was found to be uniformly coated having mean fiber diameter ranges from 1210-1221 nm. AFM microphotographs indicated the interconnected porous structure of the prepared Chitosan web. Fibrous break down at a solution concentration (2 & 5 %) was revealed by AFM and FESEM images. At higher concentration (14%) web spinability was poor in the form of lumps deposition. Morphology of spun web was greatly influenced by coating density. Thus, these nanofibrous coated membranes have great potential for using as a layer for developing futuristic antimicrobial, biomedical and filtration clothing. Moreover, the developed coated web has a significantly higher production rate (approx 0.25 g/m2min) is potential for commercial viability and could be translated into bulk production.
Modification of Si-Based Consolidants by the Addition of Colloidal Nanoparticles: Application in Porous Stones
Authors: Ksinopoulou E. , Bakolas A. , Moropoulou A.
Published: March 2014

Si-based consolidants, most widely used in the restoration of porous stones exposed to the environmental decay mechanisms, present some serious limitations, such as the tendency to crack and shrink during drying. This deficiency has been the focus of several studies with the objective of modifying and improving the above mentioned materials. The addition of nanoparticle dispersions into silica matrix has been found to enhance their effectiveness in several respects. Objective of the current research was to study the preparation of particle modified consolidants (PMC), consisting of an ethyl silicate matrix loaded with colloidal oxide titania (TiO2) particles and silica (SiO2) nanoparticles and the evaluation of their consolidation effect, applied to different porous limestones. Two compositions were prepared and then evaluated based on their stability in the liquid phase, the particle size, the% solids content and their morphological characteristics during the drying process. The characterization of the particles is made through dynamic light scattering (DLS). Penetration depth of the material is examined by scanning electron microscopy (SEM-EDAX). The color changes of the treated surfaces were measured by a portable spectrophotometer before and after treatment. Changes in the porosity and characteristics of the microstructure were determined by applying mercury porosimetry in untreated and treated samples. Based on the techniques applied, PMCs appear to be promising materials in stone consolidation, as they show a reduction of silicate network shrinkage and cracking during drying compared with the silicon-based consolidant. Treatment causes some changes in the properties of the substrate such as a reduction of the % water uptake (up to 15%) as well as an increase in the elastic modulus (up to 10%).
Multi-Physics Coupled FEM Method to Simulate the Formation of Crater-Like Taylor Cone in Electrospinning of Nanofibers
Authors: Liu Yong , Li Jia , Tian Yu , Liu Jian , Fan Jie
Published: March 2014

Crater-like Taylor cone electrospinning is a novel, simple, and powerful approach to mass produce nanofibers. The Taylor cone, crater-like liquid bump on the free liquid surface, in this electrospinning process plays a key role to produce multiple fluid jets which finally solidifies nanofibers. A multi-physics coupled FEM method was employed to simulate the dynamic formation process of crater-like Taylor Cone in crater-like electrospinning. A blended k−ω /k−ε model for turbulence and dynamic overset grids to resolve large amplitude motions were used to simulate two-dimensional uncompressed flow, which was described in axisymmetrical coordinates. The numerical calculation results were obtained by a computational fluid dynamics (CFD) method. The effect of gas flow on the formation of crater-like Taylor cone and the production of nanofibers were also discussed. The experiments were carried out to validate the numerical results. The Polyvinyl Alcohol (PVA)/ distilled water solution with 18wt% and the air pressures ranged varied from 4 to 50kPa were used in our experiments. The results showed that the numerical results were in good agreement with the experimental results. This work provides a deep understanding of the mechanisms of micro fluid jets production in electrospinning processes and two-phase flow in specific type of industrial equipment.
Low-Temperature Growth of Vertically Aligned Carbon Nanotubes on a Glass Substrate Using Low Power PECVD
Authors: Tabatabaei M.K. , Ghafoori Fard H. , Koohsorkhi J.
Published: March 2014

In the traditional PECVD method for growing carbon nanotubes (CNTs), the electric field is an important parameter. Its role is to orient CNT growth and dissociate the H-C bond from hydrocarbon gases. Therefore, high energy ions, molecules, and radicals as plasma elements can affect the verticality of CNTs. In this paper, a new configuration for an electric field for the growth of field-oriented and long CNTs on a glass substrate at temperatures below 400°C is reported. Simulation and experimental data show that CNTs are grown at a considerably lower voltage than traditional methods. Using this method, growing vertical CNT on such low-cost substrate glass is more possible for CNT-based devices and bio-applications where price is important.
Characterization of Surface Nanostructures on“Thin” Polyolephine Foils
Authors: Řezníčková Alena , Kolská Zdeňka , Sajdl Petr , Švorčík Václav
Published: March 2014

Surface properties of nanostructures on 7 polyolephine foils were characterized using different analytical methods to discuss an effect of halogen presence in polymer chain to surface properties. Both sides of these foils were examined and compared. Surface roughness and morphology were determined by atomic force microscopy, contact angle by goniometry, surface polarity by electrokinetic analysis. X-ray photoelectron and ultraviolet visible spectroscopies were used for determination of surface chemistry. Combination of different analyses gives complex information about surface properties of the foils, which may be of importance for any future experiments, as well as for their application e.g. in tissue engineering and electronics.
Characterisation of Mechanical Properties by Small Punch Test
Authors: Siegl Jan , Haušild Petr , Janča Adam , Kopřiva Radim , Kytka Miloš
Published: March 2014

The specific desired properties for structures and components working in critical environments (e.g. different structure parts of power plants) require current information about degradation processes coming out in materials. Obtaining of this information by the help of the classical tests of mechanical properties (tensile test, Charpy test, fracture toughness test, creep test etc.) is very limited namely in the case of nuclear power plants pressure vessel. Hence, the new innovative techniques based on miniaturized specimens have been developed for evaluation of mechanical properties and their changes. One of very promising techniques is Small Punch Test. Present paper deals with characterization of three different steels (15Ch2MFA, 10GN2MFA with different heat treatment and steel O8Ch18NT10 with various degree of deformation).
Study of the Nanoindentation Induced Defects in Nanocomposite n-TiC/a-C:H Films
Authors: Buršíková Vilma , Buršík Jiří , Zábranský Lukáš , Vašina Petr , Souček Pavel , Peřina Vratislav
Published: March 2014

The aim of the present work is to study the nanoindentation induced defects in as-deposited and annealed nanocomposite n-TiC/a-C:H coatings. Furthermore, the resistance of the coatings against indentation induced defect creation was studied using TEM analysis of lamellas prepared using a focused ion beam for both as-deposited and annealed samples.
Evaluation of Failure Micromechanisms of Advanced Thermal Spray Coatings by In Situ Experiment
Authors: Mušálek Radek , Taltavull Catalina , Galisteo Antonio Julio Lopez , Curry Nicholas
Published: March 2014

Identification of failure mechanisms of thermal spray coatings by means of traditional fractography of failed parts is often troublesome. Reason for this is a highly inhomogeneous character of the coating microstructure and harsh in-service conditions which may hinder evidentiary fractographic marks. In this study, failure evolution of advanced thermal barrier coating (TBC) prepared by plasma spraying was studied in-situ at high magnification in a scanning electron microscope under well-defined laboratory conditions of three-point bending (3PB).
Nanohardness of CrN Coatings versus Deposition Parameters
Authors: Hviščová Petra , Lofaj František , Novák Michal
Published: March 2014

Nanohardness of chromium nitrid coatings deposited with DC magnetron from Cr target in the reactive atmosphere with various percentual contribution of nitrogen in Ar flow was investigated to determine the influence of nitrogen content and negative bias. The nanohardness of pure Cr coating was between 11 14 GPa and the addition of 50 % of nitrogen into Ar flow resulted in the increase of coating hardness up to ~ 22 GPa. The highest hardness of the studied CrN coatings of ~ 28 GPa was achieved at 700 W power, working pressure of 0.5 Pa with 50 % of nitrogen in Ar flow and negative bias of-30 V . The increase was ascribed to the formation of near-stoichiometric CrN compounds.
Computer Nonlinear Analysis of the Formation and Development of Cracks in a Travertine Stone Pavement Exposed to Bending Stress Caused by a Single Load
Authors: Tej Petr , Vacek Vítězslav , Kolisko Jiří , Čech Jindřich
Published: March 2014

This paper focuses on a computer nonlinear analysis of the formation and development of cracks in a travertine stone pavement. The causes of cracking in the upper travertine layer of the tested multi-layer floor are modeled and investigated by a computer nonlinear static analysis. The paper illustrates the setting of material characteristics of the stone in the design of the material model according to the performed destructive and non-destructive laboratory tests.
Computer Nonlinear Analysis of the Formation and Development of Cracks in a Reinforced Concrete Slab Loaded by a Planar Uniform Load
Authors: Tej Petr , Vacek Vítězslav , Kolisko Jiří , Čech Jindřich
Published: March 2014

The paper focuses on a computer nonlinear analysis of the formation and development of cracks in a concrete slab exposed to a uniform continuous load on the lower surface. The analysis is based on an actual example of the formation and development of cracks in a basement slab exposed to ground water buoyancy.
Corelation of Results of Creep and Micro-Indentation Creep for PP-Copo
Authors: Reznicek Martin , Ovsik Martin , Manas David , Skrobak Adam , Stanek Michal , Senkerik Vojtech
Published: March 2014

This article deals with the comparison of methods for measuring the creep behavior of filled polypropylene. Creep was measured by two methods, using the micro-indentation method (Depth Sensing Indentation - DSI) and the standard long-term creep test at elevated temperature. Results of this article show the feasibility of these two methods to replace each other and thus shorten the length of the testing material development with evaluation whether the test material is better or worse than the previous. Using the DSI method we can evaluated other material properties at the same time, which may be an important contributor in determining an appropriate application of the material. Mixtures of polypropylene with different kinds and levels of filling were selected for the comparison.
Numerical Model of Instrumented Indentation by a Rounded Cone Indenter Using Finite Element Method
Authors: Kocmanová Lenka , Haušild Petr , Materna Aleš , Matějíček Jiří
Published: March 2014

The paper serves as an introduction to investigation of mechanical properties of functionally graded materials and deals with elastic nanoindentation numerical models. The models were based on the finite element method. Young's moduli were estimated by Oliver-Pharr method. The indenter geometry for which numerical solutions were accomplished was a rounded cone indenter. The effect of tip sharpness was examined by applying an increasing spherical tip radius. The results show that the apparent Young's modulus and the hardness increase linearly with increasing radius of the tip. The effect of approaching interface between two elastic materials on the apparent hardness and indentation modulus was identified in 3D model. The specimen consisted of two materials. First, the interface was linear and parallel to the direction of indentation, so that the Young's modulus changed suddenly. Second, the Young's modulus was continuously changing. The dependence on various boundary conditions of the specimen was also considered.
Effect of Grit-Blasting on Residual Stress Field
Authors: Kovářík Ondřej , Haušild Petr , Pala Zdenek , Sachr Pavel , Davydov Vadim
Published: March 2014

The effect of grit-blasting on the development of residual stress field during the surface treatment of the cold rolled mild steel was characterized by means of neutron diffraction, nanohardness measurement and electron back-scatter diffraction. The neutron diffraction revealed strong residual compressive stress with the maximum value (about-100 MPa) situated just under the sample surface of the grit-blasted sample. The deformation profiles obtained by the nanoindentation and electron back-scatter diffraction (band slope signal) revealed the strain hardening after grit blasting up to depth of approximately 100 μm.
Structural, Morphological, Vibrational and Electrical Studies on Zn Doped Nanocrystalline LiNiPO4
Authors: Karthickprabhu S. , Hirankumar G. , Maheswaran A. , Daries Bella R.S. , Sanjeeviraja C.
Published: March 2014

Olivine structured LiNi1-xZnxPO4 (x=0, 0.05, 0.10, 0.15, 0.20) have been prepared by a polyol method using 1, 2 propanediol as a polyol medium. The XRD results of pure and Zn doped LiNiPO4 sample authenticate the orthorhombic crystal structure with high crystalline nature. The crystallite size is calculated from the Debye Scherer formula and it is found in the range of 55-65nm and 49-55nm for undoped and doped samples respectively. The thermal properties of LiNi1-xZnxPO4 were investigated by thermo gravimetric analysis (TG) and differential thermal analysis. Laser Raman studies confirm that the dopant is entered in to the LiNiPO4 lattice. Morphology of the samples is analyzed through SEM analysis. The higher electrical conductivity is calculated for LiNi0.85Zn0.15PO4 sample compared with other concentrations of dopant and it is found to be 1.08×10-7 S cm-1 at ambient temperature. Dielectric and Modulus studies are also discussed through impedance spectroscopy.
A Review on Application of Multifunctional Mesoporous Nanoparticles in Controlled Release of Drug Delivery
Authors: Dave Pragnesh N. , Chopda Lakha V.
Published: March 2014

In the early 1990s the discovery of the MCM-41 and the M41S family of mesoporous materials had open new era in the chemistry and biology. They have prominent application inbiotechnological, biomedical and heterogeneous catalysts. Mesoporous silica nanoparticles (MSNs) exhibit unique structural features like as their large surface areas, tunable pore sizes in nanometer and well-defined surface properties. MSN materials which are comprised of a honeycomb-like porous structure with hundreds of empty mesoporous channel that are able to encapsulate relatively large amounts of biomolecules. They are ideal candidate for constructing multifunctional materials that encapsulate a variety of functional nanostructured materials. Multifunctional MSN materials have become one of the most attractive areas in nanobiotechnology and nanomedicine for various disease diagnosis and therapy. Multifunctional MSN have been successfully developed as a multifunctional platform to deliver therapeutic and diagnostic agents. Multifunctional MSNs are a highly promising platform for intracellular controlled release of drugs. In this review we discuss the recent developments in design and fabrication of multifunctional mesoporous silica nanoparticles in as efficient drug delivery applications such as the site-specific delivery and intracellular controlled release of drugs.Abbreviations;APTES; 3-aminopropyl triethoxy sialne, ATP; Adenosine triphospahate, CD; cyclodextrinCPT; camptothecin, CS; Chitosan,CTAB; cyltrimethylammonium bromide,DNA; Deoxyribonucleic acid,DOX; doxorubicin,EDC; 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide,FD; fluorescein disodium,FSP;Fluroscent particle ,IBU;ibuprofen,MCM; mobil composition material, MPS; 3-trimethoxylsilyl propyl methacrylate, MS; mesoporous silica,MSN; mesoporous silica nanoparticle, MSNs; mesoporous silica nanoparticles,MSNP; mesoporous silica nanoparticle,NPS; nanoparticles;PFDTES;perfluorodecyltriethoxysilane, PAA; polyacrylic acid,PR;photo responsive,PMAA; polymethyl methacrylate,SBF; simulated body fluid,TEOS;tetraethyl orthosilicate,TUNA;Thio undecyl-tetraethyleneglycoestero-nitrobenzylethyldimethyl ammonium bromide.
Fibrous Noble Opals: Electron and Atomic-Force Microscopy and Spectrometry Data
Authors: Aseeva Anna Valer`evna , Vysotskiy Sergei Viktorovich , Galkin Konstantin Nickolaevich , Bushkareva Kseniya Yur`evna , Karabtsov Alexander Alexandrovich , Okrugin Andrew Sergeevich
Published: March 2014

The work deals with results of study of hydrothermal noble opals. It has been established that hydrothermal opals are composed of multiple clusters: chaotic packs, fibers and grid layers. An effect of the water saturation coefficient on the opal optical properties was considered.
Phase Transformation in Titanium Nanoparticles from First Principles
Authors: Chibisov Andrey N.
Published: March 2014

We have used molecular dynamics and first-principles calculations to investigate the structure and agglomeration of Ti nanoparticles. The results indicate that Ti nanoclusters undergo a phase transition with a change of point group symmetry. In addition, we found that titanium nanocluster growth occurred along the [0001] direction.