bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of B2O3 Flux on the Crystal Structure, Dielectric Properties of (K 0.5Na0.5)NbO3 Single Crystal Grown by Flux Method
Authors: Saravanan Rajemepu , Rajesh Dodla , Rajasekaran S. Velu , Perumal Rajakempu , Chitra M. , Jayavel Ramaswamy
Published: October 2012

Lead free piezoelectric single crystals of sodium potassium niobate (K 0.5Na0.5)NbO3 single crystals were grown by high-temperature solution method using B2O3 flux The KNN crystals grown by without B2O3 flux and with B2O3 flux are referred to as samples A and B respectively. It was found that additions of small amounts of boron oxide B2O3 further lower the melting temperature of the eutectic mixture and exhibits excellent dielectric properties. Phase analysis showed that all samples crystallized in pure orthorhombic perovskite phase. AFM morphological studies show that the root mean square (rms) roughness values were measured to be, 5.3nm and 6.96nm for the sample A and sample B crystal respectively. A slight decrease in the orthorhombic to tetragonal phase transition temperature TOT> and Curie temperature Tc has been observed in sample B when compared with sample A.
Thermoelectric Property in Multiferroics
Authors: Ramachandran T. , Rajeevan Nhalil E. , Pradyumnan P.P.
Published: October 2012

Thermoelectricity has gained special interest due to its potential applications, especially the advancements in the electronic devices with very low power consumption. Thermoelectric materials can be used to make energy conversion devices that generate power from thermal sources. Multiferroic oxides, in particular cobaltates, have been actively studied as a new type of thermoelectric material (1). The crystal structure of these cobaltates offers a possibility to manipulate Seebeck coefficient, electric conductivity, and thermal conductivity to optimize the figure of merit ZT. The theoretical explanation and experimental observations by some investigators proved the candidature of multiferroic materials for thermoelectric generation. Many semiconducting multiferroic oxides are showing spin dependent Seebeck coefficient (2-3). Moreover, most of these oxides are inherently stable at high temperatures in air, making them a suitable material for high temperature applications. In this work we have investigated the multiferroic and thermoelectric properties of thinfilms of doped cobalt oxide matrices. The observations confirmed that these materials are suitable for thermoelectric generation.
Spin-Coating Temperature Induced Changes in Ferroelectric Crystallinity in Polyvinylidene Fluoride Ultrathin Films
Authors: Dhevi Dhevagoti Manjula , Prabu Arun Anand , Pathak Madhvesh , Kim Kap Jin
Published: October 2012

In the present study, calculated amount of polyvinylidene fluoride (PVDF) was added to a mixture of two different polar solvents and maintained under continuous stirring for overnight. The PVDF solution thus obtained was spin-coated over divergent substrates like KBr and gold coated glass substrates at 80 oC. The spin-coated samples were further exposed to varying thermal conditions such as as-cast (AC), annealed at 130 °C (AN) and melt (200 °C)-slow cooled (MSC) for a period of time. FTIR spectroscopic data obtained from this study was found to be quite useful in analyzing the changes in absorption intensity of crystalline phase changes as a function of varying substrate and heat treatment conditions. Aβ,γ,α/A1073 ratio was observed to be favorable for AN samples when compared to that of AC and MSC samples, and among the substrates, gold is more preferable due to its real-time usage as a substrate in electronic device applications.
Wet Chemical Synthesis and Characterization of MnS Nanoparticles
Authors: Chaki Sunil H. , Deshpande M.P. , Tailor J.P. , Mahato K.S. , Chaudhary M.D.
Published: October 2012

The manganese sulfide, MnS, is a wide bandgap (Eg = 3.1eV) diluted magnetic semiconductor belonging to the VIIB-VIA family with outstanding magneto-optical properties. The authors report the synthesis and characterization of MnS nanoparticles. The MnS nanoparticles were synthesized by simple wet chemical method at ambient temperature. Manganese acetate (C4H6MnO4.4H2O) was used as source for Mn+2 ions and thioacetamide (C2H5NS) was used as source for S-2 ions. The energy dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD) were used for stoichiometric and structural characterization of the synthesized nanoparticles respectively. The crystallite size calculated from XRD using Scherrer’s formula and Hall-Williamson relation came out to be of 6.81 nm and 5.27 nm respectively. The optical absorption spectra showed absorption edge at 325 nm corresponding to energy of 3.82 eV, which acknowledged the occurrence of blue shift. The photoluminescence spectra recorded for five different excitation wavelengths viz 250, 275, 280, 300 and 325 nm showed three emission peaks at 463 nm, 550 nm and 821 nm. The TEM and SEM analysis of the particles clearly shows the particles are spherical in shape. The selected area electron diffraction (SAED) pattern showed ring pattern, stating the nanoparticles to be polycrystalline. The obtained results are discussed in details.
Oxidative Degradation of Rhodamine B Catalysed by Copper Oxide Nanoparticles in Aqueous Medium
Authors: Parimala Lakshmikanthan , Santhanalakshmi J.
Published: October 2012

In the present work , copper oxide nanoparticles are synthesized by wet sol – gel method using sodium hydroxide as the precipitating agent and starch as the capping agent. Size characterization of the nanoparticle was done by TEM, XRD and FT – IR. The as prepared nanoparticles are used as catalyst in the degradation Rhodamine B dye using hydrogen peroxide.The effects of H2O2 dosage, medium pH, solution temperature, and the dye compositions on the degradation kinetics of rhodamine B have been studied. The pH=4 and temperature = 40◦c are the optimized conditions.
Room Temperature Synthesis and Properties of Pure and Gadolinium Doped Dy2O3 Nanoparticles
Authors: Chandar Nagamuthuraja Krishna , Jayavel Ramasamy
Published: October 2012

Pure and gadolinium doped Dy2O3nanoparticles were prepared by a convenient, wet chemical synthesis route and the particles were subjected to thermal, structural, morphological and optical property studies. The influence of gadolinium on particle size, lattice parameter and band gap energies were investigated. Structural and optical properties of the particles elucidated that the Gd3+ions have substituted the Dy3+ions without changing the cubic structure of Dy2O3. The optical property studies of Gd:Dy2O3nanoparticles showed enhanced optical absorption in UV region with respect to pure sample. The samples also exhibited room temperature PL, having a strong emission in the visible region.
Optimisation on the Growth and Alignment of ZnO Nanorods
Authors: Ranjith Kugalur Shanmugam , Pandian Ramanathaswamy , Natarajan Gomathi , Kamruddin Mohammed , Rajendrakumar Ramasamy Thangavelu
Published: October 2012

Synthesis of aligned ZnO nanorods (NRs) is important for electronic and optoelectronic devices. In this work we demonstrate the growth of ZnO nanorods by co-precipitation method using zinc nitrate and hexamine precursors. The samples were characterized by X-ray diffraction analysis, Scanning electron microscopy and Raman spectroscopy. On introducing the seeded substrate into the growth solution, the seeds offer nucleation sites for one-dimensional growth of ZnO nanorods. ZnO nanorod arrays grown on the successive ionic layer adsorption and reaction (SILAR) seed layer found to be irregular and non-uniform due to the etching of the seed substrate by growth solution. However, dip-coated seed substrate yielded uniform growth of ZnO nanostructures. ZnO nanostructures with flower-like morphology were obtained for pH of 9. On reducing the pH of the growth solution the flower morphology transformed into rod-like morphology with rod diameter of 200nm. On reducing the pH to 3 the diameter of the nanorods is decreased to 20 to 25nm. On reducing the precursor concentration the faceted morphology of the nanorods changed into needle-like shape (with sharp tips) along with reduction in diameter (about 20nm). The growth of uniform and vertically aligned ZnO nanorods is observed in dip-coated seed substrate with 5 pH. The results indicate that the diameter of ZnO nanorod array could be controlled by varying the precursor concentration.
A Polyol Route LiFePO4 Cathode Material for Li-Batteries
Authors: Muruganantham Rasu , Subadevi Rengapillai , Sivakumar Marimuthu
Published: October 2012

Lithium ion battery technology has played a key role in portable electronics revolution, and it is vigorously pursued for electric vehicle applications. LiFePO4 has recently received a great deal of attention due to its potential usage as a next-generation cathode material for lithium-ion batteries such as power tools, electric vehicles (EVs)and hybrid electric vehicles (HEVs),etc.LiFePO4 is advantageous when comparing other conventional cathode materials such as LiCoO2, LiNiO2 and LiMn2O4, namely, it is inexpensive, environmentally benign and thermally stable, etc.. In the present work, LiFePO4 has been prepared using polyol method and its crystal structure has been confirmed by powder X-ray diffraction. The as-prepared LiFePO4 has olivine structure with space group Pnma and orthorhombic lattice parameters are calculated as a=10.3999Å, b=6.0070Å and c=4.6388Å. The functional group vibrations have been analyzed using Fourier Transform Infrared Spectroscopy (FT-IR). The surface morphology of synthesized material have been studied by scanning electron microscopy (SEM) and the compositional analysis were also been carried out through EDX analysis.
Green-Chemical Synthesis of ETS-4 Zeotypes for Photocatalytic Hydrogen Production
Authors: Shankar M.V. , Ye Jin Hua
Published: October 2012

Pristine ETS-4, a microporous titanosilicate zeotype material was successfully synthesized by using inorganic alkaline-sols as precursors for the first time. Use of halogen/organic free medium, drastic reduction in excess amount of alkali precursors and short synthesis time makes this methodology much more versatile. Sr-ETS-4 material was prepared using ion-exchange process. Structural, optical, bulk and surface properties of the synthesized materials were thoroughly examined and their properties are interpreted. The photocatalytic experiments were conducted under UV light irradiation. Further, Sr-ETS-4 material has showed ca. 4 times higher photocatalytic efficiency for photocatalytic methanol reforming as compared with pristine ETS-4 catalyst. The observed higher photocatalytic efficiency of Sr-ETS-4 catalyst might be attributed to better electron transfer properties of Sr-ion and semiconducting property of one-dimensional titanium chains within zeotype structure.
FTIR, FTR Spectral Analysis and DFT Calculations of 1, 8-Dimethyl Naphthalene
Authors: Pouchaname V. , Madivanane R. , Tinabaye A.
Published: October 2012

ABSTRACT. Solid phase FTIR and FT-Raman spectra of 1, 8-dimethylnaphthalene have been recorded in the region 3700-50 cm-1. The spectra were interpreted with aid of normal coordinate analysis based on DFT using standard B3LYP/6-31G basis sets. After scaling there is good agreement between observed and calculated frequencies. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.
Photo Catalytic Activity of Anatase TiO2/PVA Film Coated Glass Plate
Authors: Revuru Aravind Naga , Padmavathy Nagarajan , Sheela Angappan , Sasikumar Swamiappan
Published: October 2012

The major cause of surface and ground water contamination is due to effluent from dyeing industries. The discharged effluent chemicals inhibit light penetration into water bodies and some are considered to be carcinogenic. In this study, the photocatalytic decomposition of the synthetic dye, methylene blue was investigated in the presence of activated TiO2. The TiO2 sample was characterized by using XRD to analyze the presence of anatase and rutile phases. The dye degradation was monitored as a change in absorbance by UV-Visible spectrophotometer. The contributing factors towards dye degradation include both the dye concentration as well as the quantity of TiO2 used. Different quantities of TiO2 in anatase phase was taken and activated under UV radiation for 15 min. and subsequently coated on to TLC plates using 5% polyvinyl alcohol as a binding agent. This photocatalytic plate was kept in the methylene blue dye solution and exposed to sunlight. The results shows that 57% of the 30ppm methylene blue dye gets degraded within 75min., when exposed to UV activated TiO2 in presence of natural sunlight.
Studies on Silica Obtained from Cow Dung Ash
Authors: Sivakumar G. , Amutha K.
Published: October 2012

The aim of the present work is to utilize the waste material cow dung ash as a valuable material for recent research work. Silica was synthesized from cow dung ash by using sol-gel process. Characteristic parameters of cow dung ash heated to 650°C and synthesized silica were studied using different methods such as FTIR, XRD and SEM-EDS analysis. The amorphous quality of the sample was improved after the ash being calcined at 650°C. Using FTIR analysis, the presence of silanol and siloxane groups of silica was found. The amorphous nature of silica was confirmed by X-ray diffractogram. SEM studies reveal that the treated cow dung ash and silica were as flakes and in homogeneous form. The silica with higher than 99% purity with different grain size was obtained. The elemental composition of the sample was determined using EDS analysis.
Studies on the Dielectric Properties of Natural Urinary Stones
Authors: Sinha Debottam , Anwar K. , Kumari K. , Jaishwal S. , Madeshwaran S. , Keshari S. , Rajan Babu D. , Vidya R. , Arunai Nambi Raj Narayanasamy
Published: October 2012

Kidney or gall-bladder stones are solid accretions (crystals) of dissolved minerals in urine or bile juice found inside the kidneys or urethras and gall bladder, with varying size from as small as a grain of sand to as large as a golf ball, the occurrence whose in the human is well known, although its pathogenesis is not well understood. According to literature, a number of biomaterials, such as collagen, blood vessel walls, DNA, RNA etc., are found to possess the property of electrets which is an electric analogue of a permanent magnet having the capability to retain quasipermanently, an induced polarization. In order to understand about the occurrence and the physical properties of stone formation in the human tissues, the study of its electret behaviour and conductivity becomes imperative which implies the fact of indulging in its growth inhibition, if their deposition is identified using scans. Thus, in this paper, in order to understand the mechanism of growth of these nephrolithiasis, we enumerated the electrical behaviour of the stone, by using the XRD (X-Ray Diffraction) analysis after their collection from different patient in and around the region and subsequently the dielectric constant of the stone was interpreted.
Optical and Mechanical Studies on Methyl N- Phenylsuccinamate (MPS)
Authors: Vivek P. , Murugakoothan P.
Published: October 2012

Single crystal of organic material Methyl N- phenylsuccinamate (MPS) has been grown by the slow evaporation technique using methanol as a solvent. The crystal belongs to orthorhombic system with non centrosymmetric space group Pna21. Optical transmittance and second harmonic generation efficiency of the grown crystals have been studied by UV-vis-NIR spectrum and Kurtz powder technique respectively. The transmittance of MPS crystal has been used to calculate the refractive index (n), the extinction coefficient (k) and reflectance (R). The laser induced surface damage threshold for the grown crystal has been measured using Nd:YAG laser. The mechanical behaviour of the MPS crystal has also been analyzed.
Effect of Rolling Temperature on Microstructure and Mechanical Properties of Cryorolled Al-Mg-Si Alloy Reinforced with 3wt% TiB2 In Situ Composite
Authors: Gopi B. , Naga Krishna N. , Sivaprasad K. , Venkateswarlu K.
Published: October 2012

The present work investigates the effect of rolling temperature on the mechanical properties and microstructural evolution of an Al-Mg-Si alloy with 3wt% TiB2 in-situ composite that was fabricated by stir casting route. The composite was rolled to a true strain of ≈0.7 at three different temperatures viz; room temperature (RT), liquid propanol (LP) and liquid nitrogen (LN) temperatures. Tensile tests revealed that the samples rolled at liquid nitrogen temperature exhibited improved properties compared to the samples rolled at other two temperatures. A tensile strength and ductility of 291 MPa and 8% respectively were exhibited by the liquid nitrogen rolled sample. The strength is observed to be ≈12% higher and ductility is ≈60% more when compared to the room temperature rolled sample. X ray diffraction peaks indicated that rolled samples exhibited considerable increase in peak broadening compared to the unrolled one, which is attributed to the increase of the lattice strain due to distortion and the decrease in grain size of the material. The enhanced mechanical properties of the liquid nitrogen rolled samples were attributed to the combined effect of grain refinement and accumulation of higher dislocation density.
Synthesis and Characterization of Linear Polymers for Non-Linear Optics through Click Chemistry Route
Authors: Kolli Balakrishna , Mishra Sarada P. , Joshi Mukesh P. , Mohan S. Raj , Dhami T.S. , Samui Asit B.
Published: October 2012

Click chemistry is used for synthesizing polymers for second order NLO study. The molecular weights found by gel-permeation chromatography (GPC), were in the range of 7000-55000 g/mol. Differential scanning calorimetry shows glass transition temperature (Tg) above 120 oC. From electronic spectra order parameter of the poled films were calculated to be 0.1-0.5. The change in surface morphology after poling was checked by atomic force microscopy. By using a pulsed Nd:YAG laser (1064nm), the second harmonic generation (SHG) intensity was measured. The SHG intensity was also studied as a function of against temperature and time respectively.
The Heat Treatment of Rheo-High Pressure Die Cast Al-Zn-Mg Alloy 7017
Authors: Möller Heinrich , Govender Gonasagren
Published: October 2012

The CSIR rheocasting system was successfully used to produce high pressure die cast plates of medium-strength, weldable, wrought Al-Zn-Mg alloy 7017. A solution treatment at 450oC for 5 h leads to insufficient dissolution of Mg and Zn, resulting in inadequate T6 mechanical properties after artificial aging. However, a solution treatment at 470oC for 5 h, followed by water quenching and artificial aging at 120oC for 24 h results in tensile properties comparable to those of wrought alloy 7017 plate and extrusions. The alloy also shows a strong room temperature aging response, making it ideal to be used after welding without any further heat treatment.
Investigation of Correlations between Shear History and Microstructure of Semi-Solid Alloys
Authors: Modigell Michael , Pola Annalisa , Suéry Michel , Zang Christoph
Published: October 2012

Rheological properties of semi-solid alloys are closely knit to the solid-phase microstructure. Parameters such as particle size distribution are commonly determined by 2D cross section analysis. The determination of mechanisms such as particle deagglomeration with increasing shear rate however, requires information on the 3D spatial distribution. By means of synchrotron radiation tomography and SEM on AlCu samples, particle size distributions and the not yet microscopically observed interrelation of shear rate and particle agglomeration in thixo-material is investigated.
Squeeze Flow of Semi-Solid Slurries
Authors: Alexandrou Andreas N. , Florides Georgios C. , Georgiou Georgios C.
Published: October 2012

A standard method used to determine material properties of semi-solid slurries is the squeeze flow experiment in which a fixed amount of material is squeezed under constant force or velocity. The relation between the force and the displacement provides information about the rheology of the slurry. The thixotropy and the time response of the sample however is rarely, if ever, taken into consideration. In this work we study how thixotropy affects the flow characteristics and consequently the predicted material properties. We show that depending on the method of compression and the thixotropic constants the flow can be significantly different. Therefore the predicted material constants can vary and hence cannot be unique.
Numerical Simulation on Rheo-Diecasting of Magnesium Matrix Composites
Authors: Yan Hong , Zhu Jian Bin , Shan Ping
Published: October 2012

The conventional liquid die casting and rheo-diecasting processes of magnesium matrix composites were studied with the numerical simulation method. The constitutive model of semi-solid Mg2Si/AM60 composite had been established in our prior study. The pressure and the inside defects of the material during rheo-diecasting is realized. The comparison of two forming processes is done. The results indicate that the rheo-diecasting won't lead to interior defects such as gas-hole etc. The simulation results are in accord with the experimental ones.
Studies on Rheocasting Using Cooling Slope
Authors: Das Prosenjit , Samanta Sudip K. , Chattaopadhyay Himadri , Dutta Pradip
Published: October 2012

In the present work, a cooling channel is employed to produce semi-solid A356 alloy slurry. To understand the transport process involved, a 3D non-isothermal, multiphase volume averaging model has been developed for simulation of the semi-solid slurry generation process in the cooling channel. For simulation purpose, the three phases considered are the parent melt, the nearly spherical grains and air as separated but highly coupled interpenetrating continua. The conservation equations of mass, momentum, energy and species have been solved for each phase and the thermal and mechanical interactions (drag force) among the phases have been considered using appropriate model. The superheated liquid alloy is poured at the top of the cooling slope/channel, where specified velocity inlet boundary condition is used in the model, and allowed to flow along gravity through the channel. The melt loses its superheat and becomes semisolid up to the end of cooling channel due to the evolving -Al grains with decreasing temperature. The air phase forms a definable air/liquid melt interface, i.e. free surface, due its low density. The results obtained from the present model includes volume fractions of three different phases considered, grain evolution, grain growth rate, size and distribution of solid grains. The effect of key process variables such as pouring temperature, slope angle of the cooling channel and cooling channel wall temperature on temperature distribution, velocity distribution, grain formation and volume fraction of different phases are also studied. The results obtained from the simulations are validated by microstructure study using SEM and quantitative image analysis of the semi-solid slurry microstructure obtained from the experimental set-up.
Effect of Superheat on Melting Rate of EEM of Al Alloys during Stirring Using the RheoMetal Process
Authors: Payandeh Mostafa , Jarfors Anders E.W. , Wessen Magnus
Published: October 2012

The RheoMetal process (previously called the Rapid S- and RSF- process) is a novel method to produce cost effective, high quality, semisolid slurries for component casting. The RheoMetal process uses an Enthalpy Exchange Material (EEM) as cooling agent to absorb heat and produce a slurry. Critical process parameters to create a slurry by robust melting of the EEM are alloy content, stirring speed, EEM to melt ratio, EEM temperature, EEM microstructural characteristics and melt superheat. In this paper, the melting sequence and melting rate of the EEM was studied experimentally. The effect of EEM composition, as well as superheat, on evolution of shape and dimension of the EEM during stirring was investigated. Initial material freezing onto the EEM was observed, followed by a stationary phase with subsequent gradual melting of the EEM. It was shown that the characteristics of freeze-on layer were strongly correlated to melt superheat, EEM temperature, as well as material composition, hence also has significant influence on the melting sequence.
The Technology and Commercialization of Thixomolding®
Authors: Decker Raymond
Published: October 2012

The history of Thixomolding®, its technology and commercialization are reviewed along with recent evolution of new technology afforded by its metallurgical structure. Since Thixomolding was introduced in the early 1990’s, it has developed to more than 400 Thixomolding machines in the United States, Canada, Japan, China, Taiwan, Hong Kong, Malaysia, Korea, Germany, Belgium and France. Applications have been established in the electronics/communication, automobile, military, hand tool, medical and sporting goods markets. Thixomoldings principal advantages are in net-shaping, consolidation of parts, safety, environmental friendliness, mechanical properties and microstructure. The virtuous isotropic and fine-grained Thixomolded® microstructure has opened the door to derivative thermal mechanical processing for generating nanostructured Mg products of high strength/density along with improved ductility, fatigue strength, corrosion resistance and formability. This thermomechanical processing (TTMP) has been applied recently to the Thixomolded precursor to further refine the grain size and eutectic phases to nanometer sizes - providing yield strength above 300 MPa, fatigue strength of 150 MPa along with elongation of >10%. Alloys so processed include AZ50L, AZ60L, AM60, AZ61L, AZ70L-TH, AZ80, AZ91D, AXJ810-TH and Thixoblended® alloys of higher Zn content. Microstructure is related to processing and properties, as predestined by the Thixomolded microstructure. Fiber Metal Laminate composites based on this nanoMAG TTMP Mg product have demonstrated yield strength up to 900 MPa, with modulus of elasticity of 90 GPa.
Refining and Recycling of Metal Scraps by Semisolid Processing
Authors: Sugiyama Sumio , Yi Meng , Yanagimoto Jun
Published: October 2012

In this study, the authors propose a new refining process different from the rheorefining (a screen method) or the melt zone method. This new refining process is based on the gradient of solidification speed of the molten metal poured into a container. The molten metal in the cylindrical container firstly solidifies to columnar crystals from the wall of the container and a liquid phase gradually changes to semisolid state and progresses to the central portion of the container. After an intended semisolid state is achieved, a backward extrusion is carried out to extract the liquid phase component. The liquid component is known to contain a lot of impurity substances. For the refining trials, three aluminium alloys were selected: wrought aluminium alloy A2011, cast aluminium alloy AC4C and aluminium beverage can scraps. Backward extrusion (extraction) was applied twice, and the amount of pure Al increased from 90.59 % in the initial ingot to 96.34 % in the refined material. This new refining process can easily achieve the purification level of the rheorefining or the melt zone method.
Influence of Nanodispersions on Properties and Microstructure Features of Cast and T6 Heat-Treated Al Si Hypoeutectic Alloys
Authors: El Mahallawi Iman , Abdelkader Hoda , Shehata Laila , Amer Asmaa , Mayer Joachim , Schwedt Alexander
Published: October 2012

Cast light metal alloys have retained their importance and unique characteristics as first candidates when cost-function relationship is considered. Hypoeutectic aluminum silicon alloys as (A356) exhibit several specific and interesting properties that qualify them to be used in many automotive and aeronautical applications. Evidence of significant enhancement in strength in the properties of Al-Si cast alloys by incorporating nano-particles have been recently presented. The present study aims at developing nano-dispersed Al-Si alloys with suitable casting methods that assure the dispersion of the nano-particles. In this work a number of cast samples of A356 were prepared by rheo-casting in a specially designed and built furnace unit allowing for the addition of the nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stirring. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated. The results obtained in this work showed enhancement in the mechanical strength of the nano-dispersed alloys, accompanied by significant increase in the elongation percentage, supported by evidence of refined dendrite arms length, and inter-lamellar spacing.
Manufacturing of Composite and Hybrid Materials by Semi Solid Forming
Authors: Riedmüller Kim Rouven , Liewald Mathias , Kertesz Levente
Published: October 2012

Materials with good mechanical properties and low density are characteristic for lightweight constructions in automotive and aerospace application as well as in the building industry. For this reason, the manufacturing of composite and hybrid materials is in focus of academic and industrial research. Because of the complex and expensive manufacturing process, the application of composite and hybrid materials in many cases is confined to niche and custom-made products. Therefore, the Institute for Metal Forming Technology (IFU) is concerned with the development of new processes for the manufacturing of metal matrix composites and hybrid components by semi-solid forming. Fibre reinforced AlSi-alloys are produced by the application of laminates made of alternating metal matrix layers and carbon fibre fabrics. Hybrid components are manufactured by the integration of higher-strength materials in the semi-solid forming process of aluminium alloys. Here, the main challenge is the integration of the reinforcing components without damaging due to high thermal and mechanical loads that are affecting during the process. These research activities are not only interesting for the mechanical engineering, but also for the civil engineering as this paper will reveal.
Geochemical anomalies in soils and uppermost siliciclastic units overlying the Phoenix uranium deposit, Athabasca Basin, Saskatchewan
Authors: Power M J , Hattori K , Sorba C , Potter E G
Published: October 2012

Many mineral deposits are concealed by younger rocks and unconsolidated glacial deposits, which make buried deposits difficult to explore using traditional exploration tools. Under the TGI4 program, this project is examining whether surficial geochemical
anomalies exist for deeply buried uranium deposits. This study selected the Phoenix deposit on Denison Mines' Wheeler River Property, located in the southeastern Athabasca Basin, northern Saskatchewan. Discovered in 2008, the deposit currently has a National Instrument 43-101 indicated resource of
approximately 40 million lbs U3O8. The uranium oxide minerals are localized within four pods termed the A, B, C and D ore zones. These pods are located mostly along the unconformity between the crystalline basement rocks and overlying Athabasca sandstone units, approximately 400 metres below the
surface. The region is characterized by gently rolling hills comprising glacial till and moraines ranging in thickness from 30 to 50 m, with continuous permafrost. A total of 226 soil samples (humus, E-, B-, and C-horizon) were collected from 59 sites along 3 transects at approximately 10 metre
intervals over the "A" and "B" ore zones. The extensive transects facilitated sampling of both "mineralized" and "background values" in the study area.
Preliminary geochemical analyses of the samples revealed the presence of U, Mo, Co, Ag and W anomalies in humus, B-horizon soil and uppermost sandstone units overlying the ore zones and directly above the basement location of a nearby northeast-trending "WS Hanging Wall" shear zone. Concentrations
in the surface media are up to 6 times background values for U, 5 times for Mo, 4 times for Co, 20 times for Ag and 18 times for W. The geochemical anomalies in the surface media and the uppermost sandstone units over the shear zone suggest that the fault has acted as a conduit for upward migration
of fluids from the deposit. This preliminary study indicates that geochemical analysis of surface media is potentially an efficient and inexpensive exploration tool for detecting deep-seated uranium deposits.
Asymmetric Exchange Rate Pass-Through in the Euro Area: New Evidence from Smooth Transition Models
Authors: Ben Cheikh Nidhaleddine
Published: October 2012

This paper examines the presence of asymmetric behavior in exchange rate passthrough (ERPT) to CPI inflation in 12 euro area (EA) countries. Using a class of nonlinear smooth transition models, the author tests for asymmetry with respect to the direction and the magnitude of exchange rate changes. On the one hand, the author finds only 5 out of 12 EA countries showing asymmetric pass-through related to exchange rate appreciations and depreciations. Results are somewhat mixed with no clear evidence about the direction of asymmetry. On the other hand, the author reports strong evidence that ERPT responds asymmetrically to the size of exchange rate changes as a result of presence of menu costs. The degree of ERPT is found to be higher for large exchange rate changes than for small ones in 9 out of 12 EA countries.
Health managers and health reform
Authors: Briggs David , Cruickshank Mary , Paliadelis Penny
Published: October 2012

This qualitative study was undertaken with a diverse sample of Australian health managers to examine their perceptions regarding the health system and to understand how they learned to become health managers. The findings showed that they viewed the health system as one of constant change, mostly non-adaptive, and a system of parts controlled by bureaucrats and political interests. While the respondents enjoyed their managerial role, they see it as contested between the professions. This study concluded that greater emphasis on the education and training of health managers and their continuing professional development is required if they are to manage increasingly complex, dynamic and changing health systems. In Australia, the health debate continues with the recently announced national health reform agenda. The perceptions of health managers in health reform and change management are important given that they are said to be central to the implementation of health reform and the management of change.
The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere-sea ice-ocean model
Authors: Blaschek M. , Renssen H.
Published: October 2012

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene Thermal Maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveal a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from a previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in a ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that the modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.
Results of Phacoemulsification with Malyugin Ring in Comparison with Manual Iris Stretching with Hooks in Eyes with Narrow Pupil
Authors: Wilczynski Michal , Wierzchowski Tomasz , Synder Aleksandra , Omulecki Wojciech
Published: October 2012

Purpose.

To evaluate the results of phacoemulsification in eyes with a narrow pupil dilated with Malyugin Ring, in comparison with manual pupillary stretching with hooks.

setting.

Department of Ophthalmology, Medical University of Lodz, Poland.

Materials and Methods.

The examined group (group 1) consisted of 23 eyes of 23 patients whose pupil was dilated using Malyugin Ring. The reference group (group 2) consisted of 17 eyes of 17 patients whose pupil was dilated manually by stretching with hooks. All patients underwent uneventful standard phacoemulsification. Patients were examined preoperatively, 1 day, and 1 month after the surgery. Best-corrected visual acuity (BCVA), intraocular pressure, anterior and posterior segment of the eye, and corneal endothelial cell density were evaluated. Statistical analysis was done using nonparametric tests.

Results.

Mean preoperative BCVA in group 1 was 0.31±0.27 and in group 2 it was 0.26±0.26 (p>0.05). In both groups there was a significant improvement in BCVA after the surgery (p<0.05). Mean postoperative BCVA in group 1 was 0.75±0.30 and in group 2 it was 0.56±0.56 (p<0.05). Mean corneal endothelial cell loss measured 30 days postoperatively amounted to 9.35±11% in group 1 and 13.77±8.0% in group 2 (p<0.05). No serious complications were found.

Conclusions.

In eyes with narrow pupil, the use of Malyugin Ring makes the surgery easier and allows for better functional results and smaller corneal endothelial cell loss in comparison with manual pupillary stretching with 2 hooks.
Anterior Ischemic Optic Neuropathy in Patient with Hereditary Spherocytosis and Coexisting Angioid Streaks
Authors: Sawada Akira , Oie Shinya , Mochizuki Kiyofumi , Yamamoto Tetsuya
Published: October 2012

Purpose.

To describe a rare case of hereditary spherocytosis (HE) with angioid streaks that developed anterior ischemic optic neuropathy (AION).

Methods.

Case report.

Results.

A 53-year-old woman with HE had a 3-day history of blurred vision in the lower hemifield in the left eye. At presentation, her visual acuity was 20/20 OD and 20/200 OS. Perimetric testing showed a relative scotoma in the superior parafoveal region in the right eye and an inferior altitudinal field defect in the left eye. Fundus examination demonstrated angioid streaks in both eyes with swelling of the optic disc in the left eye. Both parvovirus B19 immunoglobulin M and immunoglobulin G were identified in her serum.

Conclusions.

This is the first report of AION in HE and coexisting angioid streaks. The infection by parvovirus itself might be involved in the development of AION.
A Century of Historical Change in the Game Preferences of American Children
Authors: Van Rheenen Derek
Published: October 2012

This paper chronicles the game preferences of American children during the twentieth century, documenting the results from four studies between 1898 and 1998. These studies are used to compare the popularity of particular activities (e.g., hopscotch, baseball) and types of activities (e.g., board games, games of individual skill) by gender over a one-hundred-year period. With this longitudinal, multistudy comparison, it is revealed that the game preferences of boys and girls have become markedly more similar. This pattern of increased play preference convergence throughout the twentieth century suggests an erosion of gender-determined institutionalized norms related to games. The dominance of electronic games and organized sport in the most recent of the four surveys not only reflects the technological advances of American society; it also indicates an increased desire for games that demand greater skill and promote role specialization.
A Case-study on the Selection of Promising Functional Starter Strains from Grape Yeasts: A Report by Student of Food Science and Technology Degree, University of Foggia (Southern Italy)
Authors: Bevilacqua Antonio , Casanova Francesco Pio , Arace Ersilia , Augello Salvatore , Carfagna Rosangela , Cedola Annamaria , Carri Susanna Delli , Stefano Fabio De , Maggio Grazia Di , Marinelli Valeria , Mazzeo Arcangela , Racioppo Angela , Corbo Maria Rosaria , Sinigaglia Milena
Published: October 2012

The main aim of this research, performed by some students in Food Science and Technology of Foggia University, is to show how perform the selection of a functional starter through a step-by-step procedure. Fifteen yeast strains were studied in order to assess their biotechnological traits, e.g. catalase, urease, B-glucosidase, pectolytic and xylanolytic activities, production of H2S, resistance to copper, SO2 and acetic acid, growth at different temperatures, alkaline pH, in presence of different amounts of ethanol and glucose, and some probiotic properties. After studying these abilities, yeasts were identified through the miniaturized system API 20 C AUX and two kinds of multivariate analyses (Cluster Analysis and Principal Component Analysis) were performed to highlight the best strains.
Near-infrared Spectroscopy for Rapid Estimation of Dry Matter Content in Whole Unpeeled Potato Tubers
Authors: Helgerud Trygve , Segtnan Vegard H. , Wold Jens P. , Ballance Simon , Knutsen Svein H. , Rukke Elling O. , Afseth Nils K.
Published: October 2012

The dry matter is one of the main quality parameters of raw and processed potatoes. In the present study, the potential of utilizing high throughput commercially available NIR interactance systems for dry matter determination in whole unpeeled potato tubers is investigated. The performance of a 2D NIR interactance instrument was compared with that of a 1D NIR interactance instrument and a traditional underwater weight apparatus. A total of 114 tubers were assessed individually with both of the NIR instruments (760-1040 nm), the underwater weight and an external reference method (freeze drying). The 1D interactance instrument obtained better prediction results than what the 2D instrument could achieve (R2=0.95, RMSECV=0.91, and R2=0.83, RMSECV=1.65, respectively). The underwater weight obtained the highest explained variance (R2=0.97), but the estimation was biased by approximately 1.5% (by weight). The poorer prediction performance of the 2D NIR interactance system can be partly explained by the lower penetration depths of the light compared to the 1D NIR interactance systems.
Effects of Chia Flour Incorporation on the Nutritive Quality and Consumer Acceptance of Chips
Authors: Coorey Ranil , Grant Alexandra , Jayasena Vijay
Published: October 2012

Gluten free, antioxidant, calcium and dietary fibre rich, chia is known to contain the highest level of omega-3 available in any cultivated plant source. The objective of this research was to develop a high protein, high dietary fibre, gluten free and omega-3 fatty acid rich chips. Four different levels of whole chia flour (5%, 10%, 12%, and 15%) were incorporated to produce chia chip. There were no significant differences in appearance, colour, flavour and overall liking between a commercial chip sample and the 5% chia chips. The chemical analysis indicated that all four trial chips are excellent sources of omega-3 and the baking process has a limited impact on their nutritional profile. For optimal consumer acceptance and nutritional benefits, the incorporation of 5% chia is recommended. With limited chia based food products currently available, a chia chip would be a well-accepted and healthy alternative to the common unhealthy chips.
El Niño–Southern Oscillation Effects on River Flows in the Lower Cape Fear River Watershed, North Carolina
Authors: Cahoon Lawrence B.
Published: October 2012

Well-known responses of regional precipitation in the southeastern United States to variation in the state of the El Niño-Southern Oscillation (ENSO) can yield similar regional responses of river discharge. Effects of ENSO on gaged river flows were examined in the lower Cape Fear River basin in southeastern North Carolina. Linear regression of monthly flows against sea surface temperatures (SST) in Niño Region 1 + 2 in the eastern equatorial Pacific identified significant effects of SST on flows, in several winter and spring months in the Black, Northeast Cape Fear, and main stem Cape Fear rivers. Major warm-phase ENSO events, as in 1997–1998, yielded almost a doubling of river discharges in the watershed, while typical cold phase events drove approximately 50% reductions in flows. River discharges have important effects on water supply for human needs, delivery of water to estuaries, and fluxes of water-borne materials to coastal waters. ENSO effects on the Cape Fear River watershed therefore have implications for adjacent estuarine and coastal ocean ecosystems at certain times.
Riparian-Zone Amphibians and Reptiles Within the Broad River Basin of South Carolina
Authors: Kern Madeleine M. , Guzy Jacquelyn C. , Price Steven J. , Hunt Stephanie D. , Eskew Evan A. , Dorcas Michael E.
Published: October 2012

An inventory of the Broad River Basin in South Carolina documented distribution and species richness of amphibians and reptiles of the area, focusing primarily on riparian zones. A list of 92 potentially occurring species was assembled for the area. Multiple survey methods were used including active searches, manual anuran calling surveys, and turtle trapping to document the herpetofauna. Using these techniques, 14 anuran, 9 salamander, 7 lizard, 16 snake, and 8 turtle species were documented. Seven of these species were of conservation concern in South Carolina. The Broad River Basin supports a diverse array of amphibian and reptile species associated with both wetland and riverine habitats. As water resources, energy demand, and urbanization continue to increase in the Piedmont region, these baseline data have important implications for conservation and future land management.
Observations on Northern Pine Snake (Pituophis m. melanoleucus) Nesting and Behavior in the North Carolina Sandhills
Authors: Beane Jeffrey C. , Pusser L. Todd
Published: October 2012

Nesting behavior in the Northern Pine Snake (Pituophis m. melanoleucus) is poorly documented outside of the New Jersey Pine Barrens. Two natural nests of P. m. melanoleucus are described from the North Carolina Sandhills. One was modified from a pre-existing subterranean refugium, and was also used by at least one adult male; one adult female; and one post-emergent, post-ecdytic hatchling Pine Snake during the same season.
Stomatal Development in Aerial Axes of Psilotum nudum (Psilotaceae)
Authors: Mickle James E. , Lumaga Maria Rosaria Barone , De Luca Paolo
Published: October 2012

Apical regions of developing aerial shoots of Psilotum nudum (L.) Beauv. were studied using both scanning electron microscopy (SEM) and light microscopy (LM) with the aim of improving our understanding of early stages in stomatal and epidermal ontogenesis. SEM samples were fixed in gluteraldehyde, critical point dried, and coated with an Au-Pd alloy. LM samples were fixed in FAA and embedded in paraffin. LM sections were stained with 0.05% toluidine blue for protein. SEM shows that P. nudum stomata develop from 20 µm-long domed meristemoid cells into guard cell mother cells (GMCs). A furrow dividing guard cells develops at 30 µm long, and wax deposition that will cover the entire cell begins at 70 µm long. LM longitudinal sections of GMCs show a cytoplasmic protein net that organizes into radial fibers, similar to reports of actin fibers in stomata of angiosperms. This study provides additional details of stomatal development in Psilotum and is the first report of an actin-like protein net in Psilotum.