bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of Mechanical Behavior of Carbon-Nanotube Reinforced Cement Mortar
Authors: Chang Li Wu , Yue Jin Chao , Sun Yu Zhou
Published: November 2011

In this study, effective dispersion of different amount of multiwall carbon nanotubes was achieved using a surfactant and in combination with the use of ultrasonic energy. The effects of surfactant and surfactant concentration on the plain cement mortar were investigated. Moreover, the mechanical behaviors of the carbon-nanotube reinforced composites were also analyzed. Experimental results indicate that the application of ultrasonic energy is absolutely necessary to produce a satisfactory dispersion of MWCNTs, and there exists an optimum weight ratio of surfactant to MWCNTs. It is found that the proper dispersion of MWCNTs can remarkably improve the flexural strength, compressive strength, and the toughness of the cement mortar composites.
A Hybrid Way for Optimizing Magnesium Matrix Composites Preparing Method
Authors: Ye Jian Xiong , Zhang Fa Yun
Published: November 2011

Magnesium matrix composites are prepared with a hybrid optimizing metod here. Different SiC volume fractions, processing temperature and stirring time have different influence on tensile strength and elongation of SiC; but how to find out the satisfied treating parameters is an unavoidable question, a hybrid method is put out and experiments prove the effectiveness of research work.
Design of Ultra-High Pressure Cylinders Based on Principle of Autofrettage
Authors: Zhang Yu Xian , Yao Fang , Men Xiao Shuang
Published: November 2011

Through the analysis of stress in ultra high-pressure cylinders, found that its stress distribution is very uneven. In order to use the principle of autofrettage for improving design of the cylinders, first with Faupel-Furbe formula to calculate estimates of diameter ratio, and thus are inner and outer diameter of the cylinder block. Then the cylinder is determined parameter of autofrettage on the cylinder such as the optimum radius of elastic-plastic junction and the optimum autofrettage pressure. Finally, analysis and calculation of stress in improved design cylinder, the results show that the improved design of cylinder have a greater degree of improvement in weight, size and stress distribution of three areas.
Key words: autofrettage; ultra-high pressure cylinders; diameter ratio; stress distribution.
Study on the Panel Fabrication for the Field Emission Display with Symmetrical Electrode Stripe
Authors: Ma Yan Xia
Published: November 2011

Using carbon nanotubes as cold cathode material, the panel fabrication for the diode field emission display (FED) with symmetrical electrode stripe was studied. The indium tin oxide (ITO) film was used as conduction electrode on the substrate plate surface, and the precise photolithography method was adopted as the high effective fabrication process. For the both cathode and anode plate, the whole ITO film would be etched in the bar form, and the divided bar ITO stripe would be arranged symmetrically. On the cathode plate surface, the printed silver slurry was used to form the cathode extension lines and the cathode insulation layer was formed with the sintered insulation slurry. Whether for the cathode ITO electrodes or for the anode ITO electrodes, the length of bar ITO electrode become small, which would be beneficial for reducing the panel working-voltage. The FED panel was sealed and measured, which possessed good field emission characteristics.
Numerical Analysis of Nonlinear Behaviors of a Flexible Rotor Dynamic System with Turbulent Journal Bearings Support
Authors: Lu Yan Jun , Zhang Yong Fang , Ma Xiao Yong , Liu Xu
Published: November 2011

For description of rotor-bearing system, a symmetrical flexible rotor supported by two turbulent journal bearings is modeled. The analysis of the rotor-bearing system is implemented under the assumptions of turbulent lubricant flow and a long bearing approximation. The bifurcation and chaos behaviors of the system are investigated for various rotational speeds. The motion equations are solved by the self-adaptive Runge-Kutta method. The numerical results show that the bifurcation of nonlinear responses of the system varies with the rotational speed of the rotor. It is found that the rich and complex dynamic behaviors of the system include period-1, period-doubling, quasi-periodic and chaotic motions etc.
The Effects of Composition on the Physical Properties of Locally Mined Ceramic Clays in the Atwima Nwabiagya District of Ghana
Authors: Nimo S.K. , Kwawukume P.S. , Boakye F.
Published: November 2011

This paper reports work done which seeks to enhance the insulating property of locally mined clays with application to the building and insulation of medium temperature furnaces. Mixtures of locally mined clays with kaolin obtained from Teleku bokasso in the Western Region of Ghana were made. Samples were mixed in different ratios to form composite bodies in the form of bricks of dimensions 7mm×7mm×7mm cast at constant pressure and sintering temperature of 1000 °C. The clays used were characterized in terms of their particle size and chemical composition. The thermal resistivity, water absorption, weight loss, shrinkage, porosity and strength of samples were determined. The results showed that for all samples studied, an increase in Teleku bokasso clay enhanced the insulating properties of the samples from an average of 0.24% for samples containing 20% Teleku bokasso to approximately 2% for samples containing 60% of Teleku bokasso. Mixtures of Teleku bokasso with Afari clay were on the average 1% more thermally resistant than those of Mfensi. Sample A3 (with 40% Teleku bokasso with Afari) is recommended for the building of local furnaces because it had its strength more than doubled (105%) and was by 2% more resistant to heat than M3 (40% Teleku bokasso with Mfensi). All samples showed low weight loss levels, low water absorption, good linear shrinkage and compressive strength.
SHM System Based on ANN for Aeronautical Applications
Authors: Katsikeros Christos , Sbarufatti Claudio , Lampeas George , Diamantakos Ioannis
Published: November 2011

In the present work a Structural Health Monitoring (SHM) system based on the use of Artificial Neural Network (ANN) method is presented that is suitable for aeronautical applications. The proposed methodology can be applied for the case of stiffened panels that are typical in aeronautical structures. The effect of sensor network layout, as well as noise applied during the training and prediction phase of the ANN application, is examined.
Outsourcing or Insourcing in the High Technology Systems Sector in a Maritime Company
Authors: Vaxevanou Anthi Z. , Konstantopoulos Nikolaos , Sakas Damianos P.
Published: November 2011

The object of this research paper is to examine the concepts of outsourcing and insourcing and their application in the high technology systems sector in a maritime company. When a company chooses to outsource the high technologies sector to an external collaborator, it needs to have the ability to specify to the service provider the required services, in order to obtain the best possible result. On the other hand, when the maritime company decides to provide the required services, it needs to have the ability to adapt its services according to the fast pace of high technology.
Pricing Strategy Dynamic Simulation Modelling within the High-Tech Sector
Authors: Terzi Marina C. , Sakas Damianos P. , Seimenis Ioannis
Published: November 2011

New Product Development (NPD) in the high-tech sector is a rapid paced concept that requires constant efforts and great market awareness. Pricing has received little attention from companies, even if systematic pricing monitoring may lead to serious conclusions regarding the proper allocation of resources and the segmentation of the marketplace. The purpose of the present study is to develop the concept of pricing strategies simulation modelling for the development of new high-tech products. The Pricing Simulation Model successfully represents the process that companies should carefully consider so as to employ the optimal pricing strategy.
Commensurability of the Structures of Boride Layers
Authors: Pechlivani E.M. , Stergioudis F.
Published: November 2011

The interaction of solid NH4HCO3 with iron, where the ammonia product has been adsorbed nondissociatively to iron surfaces at low temperatures [1] was investigated. The nitride clusters formed on steel substrates modified the surface morphology and characteristics of the substrate and influenced their adhesion during subsequent procedure of coating. In our case, efforts were made to decorate the steel substrate in order to influence the base metal reactivity towards boron and its ability to react and form stable compounds with boron [2]. Boride layers on steel are examined by means of SEM and XRD analysis. The decorated surface was observed by FTIR method.
Refractive Index Sensing Based on a Fiber Bragg Grating with Micro-Holes
Authors: Yang Min Wei , Wang D. N. , Liao C. R.
Published: November 2011

A refractive index sensor based on single fiber Bragg grating with multiple micro-holes is proposed. The micro-holes are drilled by use of femtosecond laser micromachining. The key feature of the sensor is that a simultaneous and independent refractive index and temperature sensing measurement can be implemented by simply detecting the grating resonant wavelength shift and its intensity variation, respectively. The refractive index sensitivity obtained is 29.50 dB/RIU (refractive index unit), within the refractive index range between 1.30 and 1.45.
Correlation between Barkhausen Noise and Plastic Deformation in TRIP 800 Steel Specimens
Authors: Varouti Eirini
Published: November 2011

The aim of this study is to contribute to a better understanding of the dependence between Magnetic Barkhausen Noise and the plastic deformation of TRIP 800 steel samples. The TRIP 800 steel samples were subjected to increasing deformation by means of tensile loading and, meanwhile, Magnetic Barkhausen Noise parameters were measured (online measurements). Magnetic Barkhausen Noise parameters were, also, measured after the tensile deformation (offline measurements). The microstructure of the samples was studied by using Scanning Electron Microscopy and, finally, micro hardness and macro hardness measurements took place.
Steel Hardness Determination Using the Barkhausen Noise Effect
Authors: Varouti Eirini , Giannouli C. , Petrakou Z. , Sapountzi K.
Published: November 2011

The Barkhausen noise technique (BHN) has been used as a non destructive tool for the measurement of the hardness in various types of steel, namely low carbon steel, TRIP steel, Duplex steel and welding in low carbon steel. The steel samples have undergone different mechanical treatment, such as plastic deformation, cold rolling or welding. Hardness and microhardness have been determined in terms of Vickers standards. A remarkably linear dependence of the BHN on the Vickers hardness of the corresponding samples with an uncertainty in the order of 3-5% has been achieved, illustrating that the BHN may be used as a non destructive tool for determining the Vickers hardness in steels. Furthermore, BHN measurements have obtained on the welding area, along the thermally affected zone and the weld itself, illustrating the theoretically expected stress field distribution.
Barkhausen Frequency Response in a-Fe Steels
Authors: Fotopoulos P.
Published: November 2011

The Barkhausen noise in low carbon steel is analyzed in this paper, illustrating a monotonic dependence on the degree of plastic deformation.
An Experimental Investigation of Magnetorheological (MR) Fluids under Quasi-Static Loadings
Authors: Mazlan Saiful Amri , Ismail Izwan , Fathi Mohamad S. , Rambat Shuib , Anis Samsol F.
Published: November 2011

In our earlier work, test equipment has been designed, simulated and fabricated to perform experiment on MR fluids in squeeze mode. Preliminary results were gathered and presented for the purpose of validating the test equipment. Therefore, in this paper, a further systematic investigation of MR fluids in squeeze mode has been carried out. As a result, MR fluids experienced rheological changes in three stages during compression and tension. Fluid-particles separation phenomenon was the main caused for the unique behaviour of MR fluids. Particle chains depended on the structure transformation in which the carrier fluid movement can be controlled by changing the magnetic field strength.
Decision-Making Processes in Transport Telematic Systems Exploitations
Authors: Siergiejczyk Mirosław
Published: November 2011

The paper discusses the key issue of decision-making support in the area of exploitation and maintenance of transport telematics equipment and systems. The scope of research studies in the decision-making processes in transport has been characterized. The decision-making processes model has been developed in exploitation of the transport telematics systems along with a description of its basic properties. The conclusion presents a general concept of the decision-making support system in the exploitation of transport telematics systems, its structure, capabilities, and the use of the proposed system.
The Dynamics of the Controlled Observation and Tracking Head Located on a Moving Vehicle
Authors: Krzysztofik Izabela
Published: November 2011

The paper analyses the dynamics of the observation and tracking head located on an off-road vehicle. The influence of kinematic forces deriving from the vehicle performing off-road assault courses was studied. Certain results of computer simulation studies have been presented in a graphic form.
Virtual Driver of Hybrid Wheeled Vehicle
Authors: Kost Gabriel , Nierychlok Andrzej
Published: November 2011

This paper presents the application of wheeled vehicle based on a hybrid propulsion system. Describes control system structure and communication between different units of propulsion, intermediary devices and the fundamental issues of building such a network. Virtual propulsion of a wheeled vehicle hybrid drive designed for parallel connection structure of the drive units. This enabled the propulsion work more efficiently through the synergy of energy units – ICE and electric motor, and allowed ICE unit turn off in built-up areas. In the presented research results can be seen as a great contribution to the work of the propulsion system has an internal combustion engine, which not only drives the electric generator, but also a wheeled vehicles.
Phase Transition, Birefringence and Orientational Order Parameter Studies in Four Members of Benzylidene Aniline Liquid Crystals
Authors: Prasad P.V. Datta , Rani G. Padmaja , Pisipati V.G.K.M.
Published: November 2011

The nature of the phase transitions across isotropic–nematic (IN) and nematic–smectic-A (N-SmA) are carried out using density measurements in N-(p-n-ethoxy benzylidene)-p-n-pentyl aniline, 2O.5, N-(p-n-methoxy benzylidene)-p-n-pentyloxy aniline, 1O.O5, N-(p-n-ethyl benzylidene)-p-n-dodecyl aniline, 2.12 and N-(p-n-butyl benzylidene)-p-n-dodecyl aniline, 4.12. The compounds exhibit IN, IN, IN and INSmA phase sequences respectively with varying thermal ranges suitable for the study of birefringence. The birefringence studies are carried out using Newton’s rings and wedge techniques which provide δn = (ne- no) (the birefringence) ne, and norespectively. The orientational order parameter, S is evaluated (i) directly from δn and Δn (the birefringence in perfect order), independent of the local field that the nematic molecule experiences and (ii) from molecular polarizabilities estimated from ne, noand density values assuming isotropic as well as anisotropic field that the nematic molecule experiences. The estimated order parameter from the different techniques is compared with one another and with the literature data.
Anomalously Large Bend Elastic Constant and Faster Electro-Optic Response in Soft Glassy Gels Formed by a Dipeptide
Authors: Nair Geetha G. , Bhargavi R.
Published: November 2011

In this article, results of static/dynamic Freedericksz transformation and rheological studies on anisotropic thermoreversible gels formed by gelation of a nematic liquid crystal (NLC) with a monodisperse dipeptide are presented. Freedericksz transformation studies reveal a surprising result: the gel state possesses a very large Frank bend elastic constant value, order of magnitude higher than the sol state, whereas, the splay elastic constant shows relatively a small increase. The studies also demonstrate that the anisotropic gel to anisotropic sol transition can be tracked by simply monitoring the Freedericksz transformation. Other attractive features of the gel state include the vanishing of the undesirable backflow effect, and nearly an order of magnitude decrease of switching speed. Further, rheological studies bring out the soft glassy characteristics of these gels.
Synthesis and Characterization of Schiff’s Base Compounds with Octadecylaniline as End Group
Authors: Reddy M.V.V. Nagi , Prasad P.V. Datta , Fakruddin K. , Kumar R. Jeevan , Latha D. Madhavi , Pisipati V.G.K.M.
Published: November 2011

The liquid crystalline compounds viz, N-(p-n-decyloxybenzylidene)-p-n-octadecyl aniline, 10O.18, N-(p-n-octadecyloxybenzylidene)-p-n-octadecylaniline, 18O.18, (p-n-biphenylbenzylidene) -p-n-octadecylaniline, PB18A and terephthalyidene-bis-p-n-octadecylaniline, TB18A have been synthesized for the first time and the characterization is carried out using thermal microscopy (TM) attached with a hot stage and differential scanning calorimeter (DSC). All the four compounds exhibit a variety of phase variants such as isotropic to smectic-F (Iso-SmF) in 10O.18, isotropic to smectic-F (Iso-SmF) in 18O.18, isotropic to smectic-A to smectic-B (SmA-SmB) in PB18A and isotropic to smectic-C to smectic-I to smectic-F (Iso-SmC-SmI-SmF) in TB18A.
Synthesis and Performance of a Novel Coumarin-Containing Side-Chain Liquid Crystalline Polymer
Authors: Zhao Yu Lei , Zhang Wei Min , Li Ji Lei , Yu Fan Fan , Pu Jia Ling
Published: November 2011

A new type of able liquid crystalline polymer with a coumarin-containing mesogenic side group that could be photo-crosslinked was synthesized in this paper. The structure of the intermediates, monomers and polymers were characterized with FTIR and 1HNMR measurement. DSC, TG, and hot stage polarized optical microscopy were employed to study the phase transition temperature, mesophase texture, and thermal stability of the liquid crystalline polymers. The results indicated that both the monomer and polymer exhibited liquid-crystalline features over a wide temperature range.
Thermal Design of LED Backlight in High Ambient Temperature
Authors: Liu Tao , Lv Guo Qiang , Feng Qi Bin , Chang Yun Fei
Published: November 2011

Different from common commercial liquid crystal displays (LCDs), LCDs in military applications have some special requirements including high luminance, wide operating temperature, and night vision compatibility. This paper designs a direct-lit LED backlight for a 5 in×5 in LCDs and puts forward three solutions for heat dissipation. The simulation results show that the solution of 17×17 LED array on common opening FR4 PCB can satisfy the requirement.
Low Power Test Pattern Design for VLSI Circuits Using Incorporate Pseudorandom and Deterministic Approach
Authors: Pan Zhong Liang , Chen Ling
Published: November 2011

The circuits should be tested extensively during the production process, the power consumption in a circuit during test mode can be higher than that the consumption during normal operation mode. The circuits are usually designed for normal operation mode, which makes it important to consider power consumption during test mode, otherwise the higher power consumption during test mode may cause the circuits being damaged. In this paper, a new approach for the test pattern design of VLSI circuits is presented, the approach defines the weight values of primary inputs of circuits, makes use of both circuit structure information and pseudorandom test generation to produce the test patterns, such that the circuit has lower power consumption when the test patterns are applied to the circuit primary inputs. The experimental results show the approach in this paper can get significant power consumption reduction compared with conventional random test algorithm.
Rolic® LCMO Photo Alignment Technology: Mechanism and Application to Large LCD Panels
Authors: Ibn-Elhaj Mohammed , Chappellet Sabrina , Lincker Frédéric
Published: November 2011

Rolic® Light Controlled Molecular Orientation (LCMO) technology is the basis for todays advanced mass production technologies for large LCD-TV panel, high-resolution 3D patterned-retarders and high-resolution optical security devices. This fundamental technology allows an easy achievement of high resolution azimuthal LC-director patterns with defined bias angles, from homogeneous planar to homeotropic orientation, depending on the target application [1-7]. In addition to the control of bias angles, LCD panel manufacturers require alignment layers with a wide range of optimized properties. Thin alignment films must be easily coatable and should have high photosensitivity in order to achieve fast processing. The photoalignment film should also have high stability and good electrical properties such as Voltage Holding Ratio (VHR), Residual DC (RDC) and image sticking. Because of in-situ photo crosslinking during processing [1, 2], our proprietary LCMO photoalignment technology is shown to be thermally and optically stable. Last years, enormous progress has been made in the development of advanced materials that meet all requirements for mass production of large-area flat panel displays. LCMO-VA technology, for vertical alignment LCDs, is the basis for the state of the art UV2A production technology recently used in the manufacturing of advanced new generation LCD-TV panel displays with reduced production costs and low energy consumption [8, 9]. LCMO-VA mechanism and performances of state of the art materials will be discussed.
Design of GRIN Liquid Crystal Lens for Autostereoscopic 2-D/3-D Switchable Display
Authors: Zhang Cai Jian , Tang Xian Zhu , Chen Chao Ping , Huang Gao Feng , Cui Hong Qing , Si Bing Yu , Chung Te Chen , Jen Tean Sen
Published: November 2011

We achieves switchable between autostereoscopic 2-view 3-D and 2-D display on a 10.1-inch LCD panel using GRIN LC lens with a 20 um cell gap and 14 volt driving voltage. Simulation results such as refraction distribution and 3-D crosstalk verify the performance of this LC lens for autostereoscopic 2-D/3-D switchable display.
Improvement the Open Circuit Voltage of Amorphous Silicon Solar Cells by Treating the P Layer with Hydrogen Plasma
Authors: Shi Ming Ji , Xiong Lei , Chen Lan Li
Published: November 2011

It is necessary to improve the open circuit voltage of amorphous silicon solar cells for its applications. In this paper, we discuss the effects of hydrogen plasma treatment on the P layer and the performance of the amorphous silicon solar cells. The result shows that the open circuit voltage increased by 0.0257V, the fill factor increased by 0.039 and the energy conversion efficiency increased by 9%. The highest VOCwe got was 0.99V. Treating P layer with hydrogen plasma has been demonstrated to result in materials with improved crystalline volume fraction which was very effective to increase the light absorption of the intrinsic layer. What is more, it could be easily integrated into the amorphous silicon solar cell mass production process.
Sol-Gel Derived ZrO2-PVP Coatings with High Laser-Induced Damage Threshold
Authors: Wang Sheng Zhao , Zhang Dan , Shi Ming Ji , Yin Ying Peng , Chen Lan Li , Luo Peng Hui , Xu Yuan , Guo Xin Feng
Published: November 2011

ZrO2 and ZrO2-PVP sol was obtained by hydrothermal synthesis. And the thin films were prepared with spin coating method. ZrO2 thin films were characterized or examined by many kinds of instruments. Fourier-transform infrared spectroscopy was employed and some infrared absorption peaks weakened when the heating temperature increased. And 1-on-1 laser-induced damage threshold tests on ZrO2 films were carried out. Refractive index and thickness of the ZrO2-PVP films were measured by means of automatic scanning spectroscopic ellipsometer and the refractive index of ZrO2 -PVP film changed with the addition of PVP content.
Crystal Morphology and Thermal Properties of PTT/POE/OMMT Nanocomposites
Authors: Run Ming Tao , Zhang Qing Chang , Zhou Wen , Zhong Yu
Published: November 2011

The crystal morphology, melt-crystallization and mechanical properties of poly (trimethylene terephthalate)/maleinized poly (octene-ethylene)/organo-montmorillonite nanocomposites were investigated by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and universal material testing machine, respectively. The results suggest that the nanocomposites form smaller or imperfect microcrystallites with lower melting point due to the influence of OMMT components and the nanocomposites have increased crystallization rate because OMMT is an effective nucleation agent. However, the crystallinity decreases because of the thickening effect of OMMT in the composites. The nanocomposite with 2%OMMT has the largest tensile and impact strength.
Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.95Zr0.05]O3−δ−xTiO2 Ceramics
Authors: Xiong Gang
Published: November 2011

Crystal structure and microwave dielectric properties of Ca [(Li1/3Nb2/3) 0.95Zr0.05]O3−δ−xTiO2(0≤x≤0.1) ceramics were investigated. A single phase with orthorhombic perovskite structure was obtained at x=0.02~0.1. With an increasing of Ti4+ content, the Qf value decreased due to a decrease of the degree of B-site 1:2 ordering. However, the τf value increased from-14.7ppm /°C to-6.9ppm/°C. When x=0.04, the optimum microwave dielectric properties: εr=31.1, Qf =21640GHz and τf =−8.8 ppm/°C.
Effect of Sodium Chloride on the Sol-Gel Synthesized Silica Colloidal Particles
Authors: Cai Yun Gao , Ma Qing Lan , Huang Yuan Ming
Published: November 2011

The effect of sodium chloride on the sol-gel synthesized silica colloidal particles has been investigated. The silica colloidal particles in the size range of 420-800 nm were synthesized from the hydrolysis and condensation of tetraethyl orthosilicate by varying the amount of sodium chloride from 15 to 30 mg while keeping the tetraethyl orthosilicate (20 ml), ethanol (125 ml), ammonia (6 ml) and distilled water (18 ml) fixed. Scanning electron microscopy (SEM) was employed to analyze the morphology of the synthesized silica particles. Our results demonstrated that: (1) sticky and spongy silica spheroids were resulted if the amount of sodium chloride was less than 15 mg; (2) spherical silica particles were resulted with good monodispersity when the amount of sodium chloride was in the range of 22-24 mg; and (3) silica spheres were obtained but with a wide size distribution when the amount of sodium chloride was more than 26 mg.
Simulation of Nematic Liquid Crystalline Polymer for Out-of-Plane Case
Authors: Fu Shu Fang , Zhang Qiang , Li Qiang Hua
Published: November 2011

The effect of magnetic fields on the molecular configuration of liquid crystalline polymers (LCPs) under simple shear flows is numerically simulated using the Doi theory when the initial state of the director is out-of-plane. A method of effectively enhance the order parameter is discussed in this paper. The simulation results show that the degree of molecular alignment can be greatly increased along the direction of the magnetic field. It is an efficient way to improve the performance of LCP materials.
Effects of the Heat Treatment on the Mechanical Properties of a Novel Thermotropic Liquid-Crystalline Polymer Fiber
Authors: Zhu Wei Biao , Gan Hai Xiao , Zhuang Yuan Yuan , Qin Wei Min , Wang Yan Ping , Wang Yi Min
Published: November 2011

Thermotropic liquid-crystalline polymers (TLCPs) have aroused wide public concern which is attributed to their high strength, stiffness, chemical resistance and perfect dimensional stability as high-performance engineering materials. Vectran heat treated after melt spinning is a representative commercial aromatic copolyester fiber. In this study, a novel TLCP melt-polymerized with 4,4’-diphenyloxide dicarboxylic acid (DODA), 4-acetoxybenzoic acid (ABA), hydroquinone diactate (HQA), 2,6-naphthalene dicarboxylic (NDA) and terephthalic acid (TA) were melt spun into fibers and heat treated to enhance the breaking strength and Young’s modulus. Intermolecular mechanical elements slipped between 120-130 °C and crystallization or the conformational rotations occurred along the extended polymer chain. For this new TLCP fiber, the optimal heat treatment temperature was 260 °C and the suitable heat-treatment time was over 48 hours. The breaking strength, Young’s modulus and breaking elongation of the as-spun fiber were improved from 1.58GPa, 45.21GPa and 1.97% to 3.20GPa, 133.44GPa and 2.42% respectively after heat treatment.
Dilatometric Study on Phase Transitions of Benzylidene-p-n-hexadecyl /Hexadecyloxy Anilines (5.O16, 5O.O16 and 5.16)
Authors: Rao M. Ramakrishna Nanachara , Prasad P.V. Datta , Latha D. Madhavi , Pisipati V.G.K.M.
Published: November 2011

Synthesis, characterization and phase transition studies (Dilatometry) have been carried out on three mesomorphic Schiff base compounds viz., N-(p-n-pentyl benzylidene)-p-n-hexadecyloxy aniline, 5.O16, N-(p-n-pentyloxy benzylidene)-p-n-hexadecyloxy aniline 5O.O16 and N-(p-n-pentyl benzylidene)-p-n-hexadecyl aniline, 5.16. The liquid crystalline phase identification and the phase transition temperatures have been carried out using SDTECHS polarising microscope attached with temperature controller with accuracy of ± 0.1 °C and for the conformation of the phase identification and the textures observed are compared with the standard textures. Further, the phase transition temperatures and the corresponding heats of transition across the phase transitions are recorded using DSC (Perkin Elmer). The characterization studies reveal that these compounds exhibit NG, N and A phase variants respectively. The nature of the phase transitions are studied through density results using dilatometric technique. The phase transitions exhibit first order nature in all the cases as expected. The results are discussed in the light of the body of the data available on other Schiff base compounds and on 5O.16.
The Impact of Antiviral Therapy and the Influence of Metabolic Cofactors on the Outcome of Chronic HCV Infection
Authors: Persico Marcello , Bruno Savino , Costantino Andrea , Mazza Marta , Almasio Piero Luigi
Published: November 2011

Natural history of HCV related chronic hepatitis is influenced and modified by many factors: virus features, coinfections and host characteristics. In particular, a peculiar genetic background of the host by conditioning the occurrence of intracellular metabolic derangements (i.e., insulin resistance) might contribute to accelerate the rate of progression to cirrhosis and eventually the occurrence of hepatocellular carcinoma (HCC) and death. Likely, direct interplays between virus genotype and host genetic background might be hypothesized at this level. Morbidity and mortality in cirrhosis is primarily associated with complications of liver cirrhosis (ascites, hepatic encephalopathy, jaundice, and gastroesophageal bleeding) and HCC occurrence. Therefore the main goal of therapy is to clear viral infection and decrease liver necro-inflammation that directly relates to development of cirrhosis and HCC. Among patients treated with Interferon-based therapy, those with sustained viral response showed a significant reduction of progression to cirrhosis and development of HCC. However, a residual risk of hepatocellular carcinoma still remains indicating the need for careful follow-up using ultrasonography every six months in cirrhotic patients, even in those showing persistently normal ALT and undetectable HCV RNA levels after antiviral therapy.
Differential item functioning of the UWES-17 in South Africa
Authors: Goliath-Yarde Leanne , Roodt Gert
Published: November 2011

Orientation: South Africa’s unique cultural diversity provides a constant challenge about the fair and unbiased use of psychological measures in respect of their cross-cultural application.Research purpose: This study assesses the Differential Item Functioning (DIF) of the Utrecht Work Engagement Scale (UWES-17) for different South African cultural groups in a South African company.Motivation for the study: Organisations are using the UWES-17 more and more in South Africa to assess work engagement. Therefore, research evidence from psychologists or assessment practitioners on its DIF across different cultural groups is necessary.Research design, approach and method: The researchers conducted a Secondary Data Analysis (SDA) on the UWES-17 sample (n = 2429) that they obtained from a cross-sectional survey undertaken in a South African Information and Communication Technology (ICT) sector company (n = 24 134). Quantitative item data on the UWES-17 scale enabled the authors to address the research question.Main findings: The researchers found uniform and/or non-uniform DIF on five of the vigour items, four of the dedication items and two of the absorption items. This also showed possible Differential Test Functioning (DTF) on the vigour and dedication dimensions.Practical/managerial implications: Based on the DIF, the researchers suggested that organisations should not use the UWES-17 comparatively for different cultural groups or employment decisions in South Africa.Contribution/value add: The study provides evidence on DIF and possible DTF for the UWES-17. However, it also raises questions about possible interaction effects that need further investigation.
Discourses regarding ethical challenges in assessments - Insights through a novel approach
Authors: Levin Madia M. , Buckett Anne
Published: November 2011

Orientation: From a pragmatic approach, a novel method called ‘the town hall focus group’ was utilised to provide insight into discourse regarding ethical issues in psychological assessments. This article contributes to the understanding of the practice of ethics in assessments and suggests the use of this particular method to facilitate discourse regarding ethical issues.Research purpose: To illustrate a forum where ethical discourse can occur in a practical fashion in order to deal with the diversity of situations, questions, demands and responsibilities experienced by psychologists.Motivation for the study: Although codes and guidelines on assessment exist, many psychologists feel that despite the existence of ethical beacons, they are often faced with challenges for which no obvious solution is evident. A need exists for ethical discourse by which psychologists grapple with unique situations through an active dialectical process.Research design, approach and method: A qualitative research approach was employed using the town hall focus group. The study was conducted with a convenience sample of 108 psychologists and practitioners.Main findings: The town hall focus group method provided an opportunity and platform for ethical discourse regarding the ethical challenges experienced by psychologists.Practical/managerial implications: This article contributes to the understanding of the practice of ethics in assessments by illustrating a platform for ethical discourse regarding ethical issues experienced in assessments. The town hall method appears to be valuable as it provides a forum to discuss ethical challenges where members are allowed to share their experiences and thus gain access to peer support, insight and shared resources.Contribution/value-add: Although the focus group results are not transferable, this article proposes it as a useful method contributing to the understanding of the ethical issues and challenges experienced in assessments. The novel method applied and described facilitates peer discourse regarding ethical challenges. This method could be replicated and applied in other contexts as a means of contending with ethical challenges within a supportive environment.
Primary pediatric gastrointestinal lymphoma
Authors: Bandyopadhyay Ranjana , Sinha Swapan Kumar , Chatterjee Uttara , Nag Dipanwita , Mukhopadhyay Subhalakshmi , Chowdhury Supriyo Roy , Biswas Pranab K
Published: November 2011

Background: Primary non-Hodgkin′s lymphoma (NHL) of the gastrointestinal (GI) tract is the most common extranodal lymphoma in pediatric age group. Yet, the overall incidence is very low. The rarity of the disease as well as variable clinical presentation prevents early detection when the possibility of cure exists. Materials and Methods: We studied six cases of primary GI NHL in pediatric age group with reference to their clinical presentation, anatomic distribution and histopathologic characteristics. Results: All were males except one. Intestinal obstruction was the presenting feature in 50%. Half the cases showed ileocaecal involvement, while large bowel was involved in 16%. Histology showed four cases of diffuse large B-cell lymphoma (DLBCL), one case of Burkitt lymphoma, and one Burkitt-like lymphoma. Immunohistochemistry for Tdt, CD20, CD3, CD30, bcl2, bcl6 confirmed the morphological diagnosis. Conclusion: Pediatric GI lymphoma commonly involves the ileocaecal region and presents with intestinal obstruction. A higher prevalence of DLBCL is found compared to other series. A high proliferative index is useful in differentiating Burkitt-like lymphoma from DLBCL.
A rare case of papillary carcinoma of choroids plexus: Its management and review of literature
Authors: Mukesh S , Janaki M G , Ponni Arul , Murali S
Published: November 2011

Papillary carcinoma of choroids plexus is very rare. Only a few cases have been described in the literature, and it is most commonly found in the pediatric population. A further observation is added now. A 20-year-old lady presented with complaints of headache and vomiting from past one and half months, headache was increasing in severity and there was relief after vomiting. On examination, no abnormality was detected in any of her systems. The patient underwent computed tomography scan of brain, which showed space occupying lesion in the right frontal lobe. She underwent near total excision of the lesion. Postoperative period was uneventful. Histopathology was suggestive of papillary carcinoma of choroids plexus and was confirmed with immunohistochemistry. The patient received whole brain radiation and intrathecal chemotherapy. The patient tolerated the treatment well, except for grade two vomiting. She has completed one and half years of follow-up and is disease free.
Theory of isotopic fractionation on facetted ice crystals
Authors: Nelson J.
Published: November 2011

Abstract. The currently used "kinetic-fractionation" (KF) model of the differential incorporation of water-molecule isotopologues into vapor-grown ice omits surface processes on crystal facets that may be important in temperature reconstructions. This article introduces the "surface-kinetic" fractionation model, a model that includes such surface processes, and shows that differences in deposition coefficients for water isotopologues can produce isotopic fractionation coefficients that significantly differ from those of KF theory. For example, if the deposition coefficient of H218O differs by just 5% from that of ordinary water (H216O), the resulting fractionation coefficient at 20% supersaturation may deviate from the KF value by up to about ±17‰, and even more at greater supersaturation. As a result, the surface-kinetic theory may significantly change how fractionation depends on supersaturation. Moreover, the model introduces possible new temperature dependencies from the deposition coefficients. These parameters need to be constrained by new laboratory measurements.
Source apportionment of carbonaceous aerosol in southern Sweden
Authors: Genberg J. , Hyder M. , Stenström K. , Bergström R. , Simpson D. , Fors E. O. , Jönsson J. Å. , Swietlicki E.
Published: November 2011

Abstract. A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C) and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80%), which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32%) and fossil fuel combustion (28%) were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.
Deriving the effect of wind speed on clean marine aerosol optical properties using the A-Train satellites
Authors: Kiliyanpilakkil V. P. , Meskhidze N.
Published: November 2011

Abstract. The relationship between "clean marine" aerosol optical properties and ocean surface wind speed is explored using remotely sensed data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO satellite and the Advanced Microwave Scanning Radiometer (AMSR-E) on board the AQUA satellite. Detailed data analyses are carried out over 15 regions selected to be representative of different areas of the global ocean for the time period from June 2006 to April 2011. Based on remotely sensed optical properties the CALIPSO algorithm is capable of discriminating "clean marine" aerosols from other types often present over the ocean (such as urban/industrial pollution, desert dust and biomass burning). The global mean optical depth of "clean marine" aerosol at 532 nm (AOD532) is found to be 0.052 ± 0.038 (mean plus or minus standard deviation). The mean layer integrated particulate depolarization ratio of marine aerosols is 0.02 ± 0.016. Integrated attenuated backscatter and color ratio of marine aerosols at 532 nm were found to be 0.003 ± 0.002 sr−1 and 0.530 ± 0.149, respectively. A logistic regression between AOD532 and 10-m surface wind speed (U10) revealed three distinct regimes. For U10 ≤ 4 m s−1 the mean CALIPSO-derived AOD532 is found to be 0.02 ± 0.003 with little dependency on the surface wind speed. For 4 < U10 ≤ 12 m s−1, representing the dominant fraction of all available data, marine aerosol optical depth is linearly correlated with the surface wind speed values, with a slope of 0.006 s m−1. In this intermediate wind speed region, the AOD532 vs. U10 regression slope derived here is comparable to previously reported values. At very high wind speed values (U10 > 18 m s−1), the AOD532-wind speed relationship showed a tendency toward leveling off, asymptotically approaching value of 0.15. The conclusions of this study regarding the aerosol extinction vs. wind speed relationship may have been influenced by the constant lidar ratio used for CALIPSO-derived AOD532. Nevertheless, active satellite sensor used in this study that allows separation of maritime wind induced component of AOD from the total AOD over the ocean could lead to improvements in optical properties of sea spray aerosols and their production mechanisms.
An open-database of Grape Harvest dates for climate research: data description and quality assessment
Authors: Daux V. , Garcia de Cortazar-Atauri I. , Yiou P. , Chuine I. , Garnier E. , Le Roy Ladurie E. , Mestre O. , Tardaguila J.
Published: November 2011

Abstract. We present a dataset of grape harvest dates (GHD) series that has been compiled from international and non-translated French and Spanish literature and from unpublished documentary sources from public organizations and from wine-growers. As of June 2011, this GHD dataset comprises 378 series mainly from France (93% of the data) as well as series from Switzerland, Italy, Spain and Luxembourg. The series have variable length and contain gaps of variable sizes. The longest and most complete ones are from Burgundy, Switzerland, Southern Rhône valley, Jura and Ile-de-France. The GHD series were grouped into 27 regions according to their location, to geomorphological and geological criteria, and to past and present grape varieties. The GHD regional composite series (GHD-RCS) were calculated and compared pairwise to assess the quality of the series. Significant (p-value < 0.001) and strong correlations exist between most of them. As expected, the correlations tended to be higher when the vineyards are closer, the highest correlation (R = 0.91) being obtained between the High Loire Valley and the Ile-de-France GHD-RCS. The strong dependence of vine cycle on temperature and, therefore, the strong link between GHD and the temperature of the growing season was also used to test the quality of the GHD series. The strongest correlations are obtained between the GHD-RCS and the temperature series of the nearest weather stations. Moreover, the GHD-RCS/temperature correlation maps show spatial patterns similar to temperature correlation maps. The stability of the correlations over time is explored. The most striking feature is their generalized deterioration at the late 19th–early 20th turning point. The possible effects on the GHD of the phylloxera crisis, which took place at this time, are discussed. The median of the standardized GHD-RCS was calculated. The distribution of the extreme years of this general synthetic series is not homogenous. Extremely late years all occur during a two-century long time-window from the early 17th to the early 19th century, while extremely early years are frequent during the 16th and since the mid-19th century. The dataset is made accessible for climate research through the Internet. It should allow a variety of climate studies, including reconstructions of atmospheric circulation over Western Europe.
Improving the characterization of initial condition for ensemble streamflow prediction using data assimilation
Authors: DeChant C. M. , Moradkhani H.
Published: November 2011

Abstract. Within the National Weather Service River Forecast System, water supply forecasting is performed through Ensemble Streamflow Prediction (ESP). ESP relies both on the estimation of initial conditions and historically resampled forcing data to produce seasonal volumetric forecasts. In the western US, the accuracy of initial condition estimation is particularly important due to the large quantities of water stored in mountain snowpack. In order to improve the estimation of snow quantities, this study explores the use of ensemble data assimilation. Rather than relying entirely on the model to create single deterministic initial snow water storage, as currently implemented in operational forecasting, this study incorporates SNOTEL data along with model predictions to create an ensemble based probabilistic estimation of snow water storage. This creates a framework to account for initial condition uncertainty in addition to forcing uncertainty. The results presented in this study suggest that data assimilation has the potential to improve ESP for probabilistic volumetric forecasts but is limited by the available observations.