bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature-Dependent Structure of a High-k (Ba,La)(Ti,Ce)O3 Ceramic
Authors: Lu Da Yong , Liu Qiao Li , Dong Yao Long , Cheng Wei
Published: March 2014

The lattice structure of a high-k BL3TC5 [(Ba1-xLax)(Ti1-x/4-yCey)O3 (x = 0.03, y = 0.05)] ceramic with cubic structure at room temperature was investigated using temperature-dependent X-ray diffraction (XRD) and Raman spectroscopy. The XRD results indicated that with increasing temperature, the cubic lattice of BL3TC5 showed a lower coefficient of linear expansion (α = 7.7 × 10-6/°C) relative to the cubic BaTiO3 (9.3 × 10-6/°C), but no abnormal change in cell volume occurred around the dielectric peak temperature Tm (= 38 °C). The peak position of the ~835 cm-1 Raman band induced by the substitution of La3+ ions for Ba sites in BL3TC5 was nearly independent of temperature on each side of Tm, whereas a slight fall (3 cm-1) in the peak position around Tm was detectable. The link between the dielectric peak with DPT and the lattice change was discussed.
Effect of Calcination Temperature on Microstructure and Microwave Absorbing Property of Ni0.5Zn0.5Fe2O4 Micro/Nanofibers
Authors: Zhao Fang , Li Jun Shou , Li Su , Wang Ming Yuan
Published: March 2014

The Ni0.5Zn0.5Fe2O4/PVP composite micro/nanofibers with average diameters of around 300~500nm were prepared by sol-gel method combined with electrospinning technology. The influences of the calcination temperatures (800°C, 900°C, 1100°C) on the crystal structure, micromorphology and microwave absorbing property of the calcined products were characterized by means of XRD, FT-IR, SEM and vector network analyzer. The results showed that the pure spinel structure of Ni0.5Zn0.5Fe2O4 were all formed when the composite micro/nanofibers were calcined at above 800°C. With the increase of calcination temperature, the Ni0.5Zn0.5Fe2O4 grains gradually grown up which contained in the micro/nanofibers, and the micro/nanofiber morphology changed toward the bamboo-like structure, and eventually lost the fiber morphology and presented the irregular granlar forms. In the band of 2~18GHz, the minimum reflectivity of the products moved to high frequency gradually. The microwave absorbing property of the products after being calcinated at 800°Cwas better than being calcinated at 900°C and 1100°C.
Low Dielectric Loss Polymer-Ceramic Composites for Wireless Temperature Sensation
Authors: Zhang Li , Yue Zhen Xing , Li Long Tu
Published: March 2014

The low dielectric loss polymer-ceramic composites with high density polyethylene (HDPE) as matrix and BaO-Nd2O3-TiO2(BNT) as filter for wireless temperature sensation were prepared by an extrusion processing technique. For 30vol % ceramic loaded HDPE, as the ambient temperature increases from 30 to 100 °C, the relative permittivity and loss tangent of the composite vary from 6.25 to 6.09 and from 0.004 to 0.011 respectively, and the temperature coefficient of relative permittivity is -370ppm/°C. By using this composite as the patch microstrip antenna substrate, a simple UHF RFID temperature sensor antenna is fabricated and measured. The experimental results show that a 2MHz/10°C frequency increment can be obtained at 900 MHz in the temperature range from 25 to 100°C.
Structure and Characteristics of ZrO2 Dielectric Thin Films by Sol-Gel Technique
Authors: Tseng Ching Fang , Chen Chiu Yun , Huang Pei Wen
Published: March 2014

Dielectric properties and microstructures of ZrO2thin films prepared by the sol-gel method at different annealing temperatures have been investigated. All films exhibited ZrO2(111) highly orientation perpendicular to the substrate surface and the grain size increased with increasing annealing temperature. Dielectric properties of the Ag/ZrO2/Ag/Si structure were measured by using HP 4192 Impedance Analyzer and Agilent 4155 Semiconductor Parameter Analyzer. The dependence of the microstructure and dielectric characteristics on annealing temperature was also investigated.
Grain Size Effects on the Properties of MPB-BSPT Ceramics under Uniaxial Compressive Stress and Electric Field
Authors: Zhang Shao Peng , Wang Xiao Hui , Li Long Tu
Published: March 2014

(1-x)BiScO3-xPbTiO3 (BSPT) ceramics with grain size range of 0.5~2.5 μm at morphotropic phase boundary (MPB) were prepared by conventional sintering method. The grain sizes of the ceramics were determined by scanning electron microscopy (SEM). The grain size effects on the structure of BPST ceramics were analyzed by X-ray diffraction (XRD). The ferroelectric hysteresis response under various uniaxial compressive stress of up to 150 MPa was measured. With increasing the mechanical uniaxial stress, the remnant polarization (Pr) and the coercive field (Ec) were significantly reduced. The direct current (DC) bias dependence of capacitance of MPB-BSPT ceramics with different grain sizes was compared. The results indicated that the domain switching was prevented by the compressive stress. The domain size and domain structure were influenced by the grain size. The domain switching under uniaxial stress and electric field became more difficult due to the decrease of grain sizes. The grain size as well as the domain size played a key role in the properties under external uniaxial compressive stress and electric field.
Preparation of Light-Weight Ceramic Microsphere by Dolomite and Gangue
Authors: Cao Xiao Wei , Liu Yan Gai , Huang Zhao Hui , Fang Ming Hao , Wen Rui Long
Published: March 2014

The ceramic microsphere was prepared by the ball milling and sintering using Dolomite and Coal Gangue as raw materials. The effects of ratio of raw materials, sintering temperature on bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres were studied. The results indicated that the ratio of raw materials, sintering temperature has some effects on the bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres. The bulk density and apparent density of the ceramic microspheres increased with sintering temperature rising. With the increasing of the ratio of dolomite, the bulk density of ceramic microspheres improved firstly and then dropped slightly, the apparent density of ceramic microspheres increased constantly. The bulk densities of the prepared ceramic microspheres were in the range of 0.570 g/cm3to 0.754 g/cm3, the apparent densities of the prepared ceramic microspheres were between 2.419 g/cm3and 2.661 g/cm3.
Study on the Conductivity of La0.4Sr1.6CoNbO6-δ as an Electrode Material for Symmetrical SOFC
Authors: Zhou Jiang Tao , Lin Xu Ping , Ai De Sheng , Ge Ben , Peng Zhi Jian
Published: March 2014

The double-perovskite La0.4Sr1.6CoNbO6-δ(LSCN) powders were synthesized by the solid-state reaction method. The electrical conductivities of LSCN samples were tested in air and 5 vol%H2/Ar. The results show that the conductivity of LSCN in 5 vol%H2/Ar (8.12 Scm-1) at 850 °C was higher than that in air (7.03 Scm-1). The activation energy obtained from the Arrhenius function was 0.821 eV in air and 0.707 eV in 5 vol%H2/Ar. The analysis of XPS shows that there exit three valence states of Co (Co+2, Co+3, Co+4) and two of Nb (Nb+4, Nb+5). The loss of lattice oxygen in LSCN not only produces oxygen vacancies, but also generates excess electrons, which contributes to the electrical conductivity of the LSCN samples.
High Performance Dye-Sensitized Solar Cells Based on Vacuum-Assisted Thermal Deposition Pt Counter Electrodes
Authors: Wang Yan Xiang , Jiang He Dong , Sun Jian
Published: March 2014

In this work, the vacuum-assisted thermal deposition platinum (Pt) film was prepared and used as a counter electrode (CE) in dye sensitized solar cell (DSC). The films were characterized by scanning electron microscopy (SEM). Electrochemical catalytic activities of the films were also characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The effects of the Pt loading amount on the fluorine-doped tin oxide (FTO) glass and titration time on the performance of the DSC were investigated. The optimal performance of the DSC was obtained when using the three-time titration with 1.69 mg/cm2 Pt loading amount vacuum-assisted thermal deposit CE. The DSC showed a high efficiency of 7.20%. The short-circuit current density (Jsc), open circuit voltage (Voc) and fill factor (FF) were 13.79 mA·cm-2, 0.73 V and 0.71, respectively.
The Synthesis and Properties of the Inverse Opals Structure Used in Dye-Sensitized Solar Cells
Authors: Zhang Yu Lin , Wang Xiao Qiang , Li Ming Ya , Wang Juan
Published: March 2014

In this paper, the inverse opal structures used in dye-sensitized solar cells were prepared by Sol-Gel method. The TiO2inverse opal photonic crystal was formed by coating glass slices using dip-coating process. The structure, surface morphology and the optical properties were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet spectrograph (UV-is). The structural characteristics of the films were investigated by the SEM showed that inverse opal titanium dioxide could trap electrons, thus enhance the photoelectric current in the dye-sensitized solar cells. By use of the inverse opals into TiO2photo anodes with the screen printing method, I-V testing measurement showed that the highest photoelectric conversion efficiency is 1.2%. And the best preparation process of inverse opal titanium dioxide is using Ti (OC4H9)4as precursor, ethanol as the solvent, nitric acid as inhibitor, and dipping-lift number for 3 times. The result of the test showed that this inverse opals structure has the most appropriate thickness and the optimal performance. Based on the research, the results indicate that the TiO2inverse opals structure could apply in dye-sensitized solar cells.
Properties and Optimization of Photoanode in Dye-Sensitized Solar Cells
Authors: Cao Hui Xia , Zhou Ze , Li Xiao Di , Wang Bo Yu , Zhang Yu Lin , Wang Xiao Qiang , Li Ming Ya
Published: March 2014

In order to improve the photoelectric conversion efficiency of dye-sensitized solar cells (DSSC), the photoanode process conditions were optimized in this work. The effects on photoelectric conversion efficiency of three methods were mainly investigated, including magnetron sputtering barrier layer, printing scattering layer and post-treatment with TiCl4. The microstructure of TiO2thin films was measured by scanning electron microscope (SEM). The results showed that porous photoanode benefited to electronic transmission. The photoelectric conversion efficiency and performance of DSSC were measured by I-V testing instrument. The results indicated that the short circuit current and photoelectric conversion efficiency were improved. Finally, the best result was obtained by combining the three optimal conditions. A high photoelectric conversion efficiency of 7.31% was achieved under illumination of simulated AM 1.5 sunlight (100mW/cm2). Compared to the previous result of 5.48%, the improvement of 33.4% was achieved.
The Preparation of TiO2 Nanotube by ZnO Nanorod Template Method and Application in Dye-Sensitized Solar Cells
Authors: Wang Yan Xiang , Ye Yu Hong , Sun Jian
Published: March 2014

Titanium dioxide (TiO2) nanotubes film was deposited on conducting glass oxide (FTO) by using ZnO nanorods as template, and the TiO2nanotubes film was applied in DSCs. First, ZnO nanorods were fabricated on ZnO-doped TiO2seed layer coated substrates by the hydrothermal method. Second, the obtained ZnO nanorods were used as a template to synthesize ZnOTiO2coreshell structure through the immersion method. Third, the ZnO nanorods template was removed by etching method to obtained TiO2nanotubes film. The thickness of ZnO-doped TiO2seed layer is about 200nm and the crystalline size of nanoparticles are about 5~10nm. The length of the ZnO nanorods are about 1~3μm. The TiO2nanotube was composed of TiO2nanoparticles. The short-circuit current density (Jsc), open-circuit voltage, fill factor (FF) and efficiency of TiO2nanotubes DSC were 4.63 mA·cm-2, 0.74V, 62% and 2.15%, respectively.
Microstructure and Thermoelectric Properties of B4C+TiB2 Composite by Hot Pressed Sintering
Authors: Zhu Zhen Ye , Zhang Xing Hong , Han Jie Cai
Published: March 2014

TiB2doped B4C composite whichTiB2contents were 12.4% and 25.4% have been fabricated by the combination of the ball milling process and hot pressing technology. The phase analysis and microstructure of the composite materials are investigated through X-ray diffraction and scan electron microscope, respectively. In addition, thermoelectric properties of the composite materials are studied. The results show that the microcracks are easy to form in the interface between B4C and TiB2. It is also found that, the electrical and thermal conductivity increase wi2. Edit Paperth the increase of TiB2doping, while the Seebeck coefficient decreases with the increase of TiB2doping. The thermoelectric figure of merit of the B4C+25.4%TiB2composite material is 50% higher than that of B4C at 573K, while the ZT of B4C+25.4% TiB2composite material is lower than that of B4C at 873K.
Preparation and Electromagnetic Properties of Al2O3/Ni Composites
Authors: Qu Zhi Xue , Wang Qun , Pang Bin , Hou Xue Cheng , Pan Wei
Published: March 2014

In this paper, a series of Al2O3/Ni composites with various content of Ni (0 vol%, 10 vol%, 20 vol%, 30 vol%, 40 vol% and 50 vol%) were prepared, and the effect of the methods and compositions on the density and electromagnetic properties was investigated. The results show that the density of the composites increases with the increasing sintering temperature as well as the increasing content of Ni. Moreover, the dielectric constant of the composites increases remarkably with the sintering temperature and the content of Ni, while the permeability shows an almost linear enhancement with the increase of Ni content. This suggests that the Al2O3/Ni composite can be expected to be a promising substrate material with certain electromagnetic compatibility.
Synthesis and Characterization of γ-Al2O3 Nanowires by a Surfactant Assisted Precipitation Method
Authors: Meng Fan Cheng , Liu Cheng , Zhang Xiao Lei , Ren Hai Shen , Jia Tie Kun
Published: March 2014

In this study, the γ-Al2O3 nanowires were prepared by a simple surfactant assisted precipitation method using the cetyltrimethyl ammonium bromide (CTAB) as a structure-directing agent (SDAs). Homemade sodium aluminate (NaAlO2) and H2O2 were used as raw materials. The influences of CTAB concentration and calcination temperature on the morphology of product were discussed. The obtained samples were investigated using transmission electron microscopy, X-ray diffraction analysis and TG-DSC. In the end, a possible formation mechanism of wire-like γ-Al2O3 is proposed.
Effect of Cd2+ Substitution on the Magnetic Properties of NiCuZn Ferrites for Low Temperature Firing
Authors: Zhang Hui , He Xi Yun , Zeng Xia , Shi Ying
Published: March 2014

Cd2+-substituted NiCuZn ferrites with compositions of Ni0.24-yCdyCu0.21Zn0.55Fe1.92O3.88(y = 0.00, 0.002, 0.005, 0.007, 0.01) were prepared by a solid state reaction method. The effects of Cd2+substitution on phase, microstructure feature and magnetic properties of samples were discussed. The results showed that NiCuZn ferrites with Cd2+substitution were single spinel phases. The lattice parameter decreased first and subsequently increased due to the difference of ions radius and incomplete substitution. The density of sintered samples had similar trend as well. The saturation magnetizationMSdecreased with the increase of Cd2+ions. The highest initial permeabilityμiand lowest relative loss factortanδ/μiwere found in the composition with Cd contenty=0.007 attributed to the decrease of crystal magnetic anisotropy constantK1of the ferrites.
Numerical Simulations of Optical Absorption and Spectral Selective of Ni Nanowire/AAO Composites
Authors: Si Xiu Li , Wu Shao Long , Yang Bo , Cheng Guo An , Zheng Rui Ting
Published: March 2014

Spectral selectivity absorber is a key component in the solar collectors, which absorbs solar energy and converts it to thermal energy by heating liquid water. Metal nanowire arrays (NWAs) have potential to be used as solar collector because of good optical absorption in the visible region. In the paper, we use finite-difference time-domain (FDTD) solutions to calculate the optical absorption and spectral selectivity of nickel (Ni) NWA/AAO composites. By changing the length (L), fill-factor (FF), and surface roughness, we simulate the optical absorption and the spectral selectivity in terms of structural parameters of Ni NWA/AAO composites. Results demonstrate that Ni NWA/AAO composites with the length of 2 μm and the fill-factor of 0.13 (the diameter is 0.04 μm) have good optical absorption and spectral selectivity,and rough surfaces is better for higher conversion efficiency of Ni NWA/AAO composites.
Photoelectrochemical Properties of NaTaO3 Microrods Prepared by Anodization
Authors: Wang Xi Xin , Liu Ji Jing , Fu Zhi Qiang , Yang Sheng Ying , Zhao Jian Ling
Published: March 2014

In this work, sodium tantalate (NaTaO3) microrods were successfully prepared by anodic oxidation of tantalum in 30% NaOH electrolyte. The morphology and structure of microrods were characterized by scanning electronic microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. SEM analysis shows the formation of microrods with an average length of 12.8 μm and a diameter of 2.3 μm. XRD analysis reveals that the as-prepared microrods are amorphous. After annealing in nitrogen at 800 °C, the amorphous NaTaO3 microrods transform into orthorhombic structure. Experimental results indicate that the microrods have a high photoelectrochemical property. The possible formation mechanism of NaTaO3 microrods has also been discussed.
Gold Nanorods: From Synthesis to Optical Properties
Authors: Ban Gui Jun , Fu Xiu Li , Peng Zhi Jian
Published: March 2014

Gold nanorods with different aspect ratios, exhibiting localized surface plasmon resonance in a tuned longitudinal mode, were prepared by employing a seed mediated growth approach. Their third-order nonlinear optical properties were investigated by using femtosecond Z-scan technique at 800 nm. All the prepared gold nanorods with different aspect ratios exhibited a reverse saturation absorbance behavior, and the value of effective nonlinear absorption coefficient reaches its maximum when the longitudinal surface plasmon resonance peak of the gold nanorods located near the excitation wavelength.
Lanthanum Dependence of the Electrically Controlled Light Scattering Performances of PLZT Transparent Ceramics
Authors: Zhang Xiao Ning , He Xi Yun , Xia Bin , Qiu Ping Sun , Cheng Wen Xiu , Zeng Xia
Published: March 2014

Lead lanthanum zirconate titanate (PLZT) transparent ceramics have attracted more and more attentions for their unique electrically controlled light scattering effects. By the hot-press sintering method, a series of PLZT (X/70/30) ceramics with different La concentration (7.3, 7.4, 7.45, 7.5, 7.6 mole %) have been synthesized to figure out its influence on the electrically controlled light scattering performances. XRD patterns reveal the formation of a single-phase perovskite structure for all samples. The PLZT (7.3/70/30, 7.4/70/30, 7.45/70/30) samples exhibit a ferroelectric behavior, but with the La concentration increasing, the samples exhibit a tendency of a double hysteresis loop which is due to antiferroelectric phase coexisted. The temperature of maximum dielectric constant (Tm) of the PLZT (X/70/30) ceramics shifts from ~99 °C to ~87 °C with the increasing of La concentration at 1 kHz. All samples exhibit a high transmittance (61%, 0.35 mm) within the wavelength range from visible to near-infrared light. Depending on the La concentration, the light scattering behavior of PLZT ceramics exhibit two main types, in which PLZT (7.45/70/30) promises a unique potential application in laser modulators for its outstanding advantages of less energy consumption and relatively larger contrast ratio.
Elastic Properties and Phase Transition of Polyoxymethylene and Ethylene-Octene Copolymer Composites
Authors: Grigalovica Agnese , Merijs Meri Remo , Zicans Janis
Published: March 2014

Multifunctional heterogeneous blends offer great possibilities of tailoring properties of materials. In this work polyoxymethylene (POM) co-polymer is blended with ethylene- octene co-polymers with various alpha-octene contents (EOC38 and EOC17) in a complete volumetric content range to fabricate specific multifunctional materials with tailored stress-strain properties. Elastic properties of POM/EOC38 and POM/EOC17 binary blends are evaluated by consideringVoigt,ReussandKernermodels. It is shown thatKernerapproach is more suitable for prediction of the modulus of the investigated blends in comparison toVoigtandReussmodels. It is shown that in both blends POM has a tendency to form continuous phase up to EOC contents of 0.61 and 0.78 vol. p. for POM/EOC38 and POM/EOC17 respectively. The tendency of EOC to form a matrix is not so expressed.
Effect of Hot Dip Galvanizing on the Mechanical Properties of High Strength Steels
Authors: Sepper Sirli , Peetsalu Priidu , Saarna Mart , Mikli Valdek , Kulu Priit
Published: March 2014

Present study focuses on investigating the hot dip galvanizing effect on the mechanical properties of high strength steel. The effect of chemical pre-treatment (hydrogen diffusion) and the effect of hot dip galvanizing temperature on mechanical properties was studied with high strength steel S650MC. Additional tests were made with widely used structural steel S355J2. A batch type hot dip galvanizing process was used and zinc bath temperature was 450 °C and 550 °C. Results of the study show the behaviour of high strength steel during hot dip galvanizing process.
Ferromagnetic Sorbents for Collection and Utilization of Oil Products
Authors: Shishkin Andrei , Mironov Viktor , Lapkovskis Vjaceslavs , Treijs Juris , Korjakins Aleksandr
Published: March 2014

This Current paper reports the research conducted at Riga Technical University and Rezekne Higher Education Institution on the development of sorbent material, which is made of closed hollow microspheres possesses ferromagnetic properties, with a large specific surface. A review and comparison of existing sorbents for oil products collection are presented. The manufacturing process of proposed sorbent are described. The structure and morphology of obtained composite sorbent are discussed. It was found that proposed sorbent allows an efficient and safe way for surface water cleaning contaminated by spilled oil products. In particular, it shows a storing effect on a thin oil film (1-2 mm). Adsorption capacity to motor oil is investigated and compared with other magnetic sorbents on metal powders base.
Newly proposed sorbent demonstrates a significantly higher adsorption capacity comparing to iron powders. Sorbent saturated by spilled oil can be evacuated by means of magnetic (or electromagnetic) captures.
Woven Textile Moisture Sensor for Enuresis Alarm Treatment
Authors: Parkova Inese
Published: March 2014

To improve comfort conditions of the enuresis alarm system, modular humidity sensor should be replaced by textile sensor. During research woven textile moisture sensor was developed and first experiments of signal detection speed were performed. Washed and unwashed samples were tested from both sides of sensor. Measurements of electrical signals were performed with oscilloscope. It is important to know what the actual resistance of a wet sensor is in order to design a proper electrical circuit that controls the state of the sensor. Acquired values of electrical resistance will be used in further sensor circuit design for developing enuresis alarm system prototype. During the design of moisture sensor it is necessary to take into consideration position of electrodes depending on sensor’s configuration and characteristics of textile wettability and moisture management.
High Efficiency Ecological Concrete
Authors: Kara Patricija , Korjakins Aleksandrs
Published: March 2014

Waste glass is cementitious in nature when it is finely ground, and especially when it is ground in a wet environment it can be finer than Portland cement. The obtained borosilicate lamp waste glass slurry with a grain size of 0.713 – 8.088 μm has shown better fineness and stability to segregation in comparison to soda-lime and soda-alkaline earth-silicate waste glasses. Elaborated high efficiency concrete with borosilicate lamp waste glass showed 120 MPa compressive strength at 28 days and it can be considered as ecological due to reduced cement content for 20% in concrete mixture without changing concrete properties in a negative way, reduced CO2 and waste glass deposits.
Bioactivity of Silver Doped Hydroxyapatite Scaffolds in Simulated Body Fluids
Authors: Poca Lasma , Dubnika Arita , Loca Dagnija , Berzina-Cimdina Liga
Published: March 2014

In the present study, thein vitrobioactivity of silver-doped hydroxyapatite (HAp/Ag) scaffolds was investigated. HAp/Ag was prepared using two different modified wet precipitation methods. The X-ray powder diffraction (XRD) results showed, that sintered HAp/Ag samples prepared using method (I) contain two phases HAp and Ag, but samples prepared by method (II) contain three different phases - HAp, Ag and AgO. After 2 month incubation period in simulated body fluid (SBF), surface of HAp/Ag scaffolds was coated with bone-like apatite. Thickness of bone-like apatite layer increased from 2 μm up to 32 μm, increasing the incubation period.
Determination of Resistance to Wear of Particulate Composite
Authors: Aruniit Aare , Antonov Maksim , Kers Jaan , Krumme Andres
Published: March 2014

Current paper concentrates on the wear resistance of a particle reinforced polymer matrix composite material. The composite material consists of unsaturated polyester resin that is filled with aluminum hydroxide. Aluminum hydroxide acts as hard phase and polyester as binding agent. The aim of the work was to understand the influence of particle size and filler material mass fraction to the wear resistance of the composite. The wear properties were determined according to standard test method using rubber wheel and silica.
Effects of Surface Modification of Titania on In Vitro Apatite-Forming Ability
Authors: Narkevica Inga , Ozolins Jurijs , Berzina-Cimdina Liga
Published: March 2014

Surface properties of a material play a significant role in manipulating biological response of living body to artificial materials. The aim of this work was put on bioactivity assessment of TiO2 ceramic after thermal treatment and further surface activation with UV-light. The in vitro apatite-forming ability was examined by soaking the samples into the simulated body fluid for several days. The research shows that nanostructural surface and UV irradiation accelerates formation of apatite on TiO2 pellets.
Effect of ZrB2, CrB2 and TiB2 Additives on the Tribological Characteristics of NiAl-Based Gas-Thermal Coatings
Authors: Umanskyi Oleksandr , Poliarus Olena , Ukrainets Maksym , Martsenyuk Iryna
Published: March 2014

In this study the influence of the TiB2, ZrB2, and CrB2 additives into NiAl-intermetallics on their wear behavior under friction conditions at the high temperature in the pair with steel has been investigated. It was shown, that the borides additives have influenced on the wear mechanism, significantly increasing the wear resistance of composite coatings pointed out. Among the coatings studied the NiAl-15 wt. % CrB2 coating showed the best result.
An Assessment of the PCM/Timber Composite in Buildings
Authors: Kazjonovs Janis , Vecstaudz Jana , Locs Janis , Bajare Diana , Korjakins Aleksandrs
Published: March 2014

This paper reviews a modeling study on PCM/timber composite materials and their incorporation in building materials, particularly in passive applications. Commercially available paraffin PCMs (RT21 and RT27) were incorporated in timber for increasing its thermal mass. In order to evaluate PCM/timber composite material behavior in building, computer simulation was performed. The obtained results showed that by using this technique it is possible to increase the thermal mass and reduce cooling loads in summer conditions.
Influence of Laser Ablation Texturing on the 40NiCrMo6 Steel Surface Layer
Authors: Napadłek Wojciech , Woźniak Adam
Published: March 2014

Laser texturing of the surface layer of materials is a modern technology with its significant prospects for production of engineering machinery. Produced with this technology oil micro-containers have a major impact on the tribological cooperation improving. The article presents methodology and results of laser texturing of surface layer of alloy steel 40NiCrMo6. The material is usually applied for foot rod of combustion engines production. Application of the laser ablation micro treatment on the side surfaces the foot of the rod allowed to fabricate desired texture in the surface layer, made of hemi-spherical and oil micro-containers.
Processing and Mechanical Properties of ZrC-ZrO2 Composites
Authors: Voltsihhin Nikolai , Hussainova Irina , Kübarsepp Jakob , Traksmaa Rainer
Published: March 2014

Sintering behavior of ZrC-ZrO2 ceramic composites processed by vacuum and spark plasma sintering routines as well as mechanical properties of the obtained materials were studied in the present paper. It has been shown that both methods of the composites fabrication are suitable for producing ZrC-ZrO2 composites; however, SPS-ed composition gives somewhat higher hardness of the bulk.
Influence of Metal Oxides Additives on the Porous Mullite Ceramics
Authors: Mahnicka-Goremikina Ludmila , Svinka Ruta , Svinka Visvaldis
Published: March 2014

The porous mullite ceramics doped with such metal oxides as ZrO2, WO3 and MgO in quantity of 5 wt% were prepared by slip casting method. The mullite phase was the main and dominant phase of ZrO2-, WO3- and MgO-doped samples, which were sintered at the temperatures of 1650°C, 1500°C, respectively. The ZrO2, WO3 and MgO had the positive effect on the increase of porosity and decrease of thermal conductivity of porous mullite ceramics and the degree of this effect was in the order of ZrO2<MgO<WO3.
Studies of TiO2 Ceramics Structure after Thermal Treatment at Different Conditions
Authors: Borodajenko Natalija , Rubenis Kristaps , Pura Agnese , Mironova-Ulmane Nina , Ozolins Jurijs , Berzina-Cimdina Liga
Published: March 2014

The present work describes results of investigation of structural characteristics of TiO2 ceramics, depending on temperature and thermal treatment conditions by using a variety of characterization techniques. TiO2 ceramics was prepared by extrusion method and developed as a material for electrodes for innovative water treatment technologies. It was shown that non-stoichiometric phase TiO1.95 was observed after thermal treatment of TiO2 ceramics under high vacuum conditions.
The Use of Sapropel in Development of Effective Thermal Insulating Materials
Authors: Balčiūnas Giedrius , Žvironaitė Jadvyga , Vėjelis Sigitas
Published: March 2014

This paper presents investigations of thermal conductivity, tensile strength and compressive stress at 10% deformation of effective thermal insulation composites made from hemp shives and sapropel. Images of hemp shives and hemp composite microstructure obtained by scaning electron microscope (SEM) are analised. The paper presents properties of composite from seven compositions. Composite forming mixture contains different amount of sapropel as well as paper production wastes (PPW) obtained in paper processing industry.
Polypropylene Composites Compounded with Natural Fibers Waste
Authors: Nestore Olga , Kajaks Janis , Jurjans Edgars
Published: March 2014

Two types fibers (hemp, flax) which are grown up in different condition and polypropylene composites exploitation properties (flexural and tensile strength/modulus and impact strength) and fluidity were evaluated. These investigations showed possibility of usage presented hemp and flax fibers as reinforcements of PP, optimal content of fibers is 30 wt.% and obtained composites have good exploitation properties.
The Microstructure of 100CrMnSi6-4 Steel after Laser Hardening
Authors: Napadłek Wojciech
Published: March 2014

This paper presents analysis of the influence of the laser hardening bearing 100CrMnSi6-4 steel on the selected properties: hardness and microstructure. The best process parameters were selected by: radiation impulse length λ = 1064 nm, different radiation power density and repetition frequency, as well as different variants of geometric surface texture. The process was carried out in a air environment, mainly in the field of ablation texturing with "thermal effect." As a result of laser hardening, the obtained martensitic microcrystalline microstructure in the superficial zone and in the middle of the hardened zone, and martensitic - bainite and bainite in the transition zone. The microstructures with high microhardness in the range of 580 850 HV0.01 are resulting from ultrafast phase transformation occurring during the crystallization of the Fe-C-Cr-Mn-Si alloy from the liquid phase. The microstructures are in the area directly adjacent to the lubricant microchannels produced during laser texturing. It was clearly noticeable on highly fragmented microstructure and confirmed by increased microhardness. There were no micro-cracks on the surface layer, what promises great technological opportunities. The results are promising and may have a significant impact on improving the tribological associations friction pair: roller - large-size track roller bearing.
The Scuffing Resistance of WC/C Coated Spiral Bevel Gears
Authors: Michalczewski Remigiusz , Kalbarczyk Marek , Tuszynski Waldemar , Szczerek Marian
Published: March 2014

One of the main problems with the operation of spiral bevel gears is related to very severe conditions in the contact of the meshing teeth; therefore, lubrication is very difficult, which increases the risk of scuffing occurrence. One of the ways to achieve better scuffing resistance is by the deposition of a low-friction coating on the bevel gears teeth. Gear scuffing tests were performed using a bevel gear test rig designed and manufactured at ITeE-PIB. The authorial bevel gear scuffing test was performed. Specially designed, spiral bevel gears were used for testing. Two material combinations were tested: uncoated pinion - coated wheel and, for reference, both gears without coatings. The a-C:H:W (trade name WC/C) coating of DLC type was deposited on the wheel teeth. A mineral, automotive gear oil of API GL-5 performance level was used for lubrication. It is shown that the resistance to scuffing may be significantly improved when the a-C:H:W coating is deposited on the spiral bevel gear teeth.
Erosion Wear of Reactive Sintered WC-TiC-Co Cermets
Authors: Tarraste Marek , Juhani Kristjan , Pirso Jüri , Viljus Mart
Published: March 2014

WC-5TiC-15Co cermets were prepared via novel technology – reactive sintering. In case of reactive sintering the elemental powders of tungsten, titanium, cobalt and carbon black are activated through ball-milling and then the synthesis of carbide occurs in the same cycle with the sintering of the cermet. Carbon content in initial powder mixture has crucial effect on properties of reactive sintered WC-based cermets. This paper investigates the erosion wear of the WC-5TiC-15Co cermets. Wear resistance dependent on the carbon content as well as wear mechanism of reactive sintered and conventional cermets are exhibited.
Influence of Alkali and Acidic Treatment on Sorption Properties of Latvian Illite Clays
Authors: Lakevičs Vitalijs , Stepanova Valentīna , Skuja Ieva , Dušenkova Inga , Ruplis Augusts
Published: March 2014

The adsorption of monovalent organic cationic dye, methylene blue, on the natural and modified with hydrochloric acid and sodium hydroxide Latvian clay samples from water solutions has been studied. It was established, that alkali and acidic treatment of Latvian clay samples changes their sorption characteristics. It was found that increasing concentration of hydrochloric acid from 5 mass % until 15 mass %, decreases adsorption of clay samples proportionally to the acid concentration. Increasing concentration of sodium hydroxide from 5 mass % to 15 mass %, BET specific surface area of the modified clay samples is lower than BET specific surface area of the natural clay sample. The studies have proven that adsorption ability of Latvian clays is sufficient for using them in waste water purification from admixtures of organic dyes.
Comparative Analysis of Residual Stresses Determined by Various Methods in Brush-Plated Hard Gold and Silver Coatings
Authors: Lille Harri , Kõo Jakub , Ryabchikov Alexander , Reitsnik Renno , Sergejev Fjodor , Mikli Valdek
Published: March 2014

The investigated brush-plated silver and gold coatings are used for refining the surface properties of electric apparatuses. Tensile residual stresses generated in the plated coatings were determined with a thin-walled ring substrate using the curvature and instrumented indentation techniques. These stresses relax over time; the dependence of relaxation time was approximated by a linear-fractional function. The modulus of elasticity and the nanohardness of the coatings were determined by nanoindentation. The surface morphology and structure in cross-section of the coated substrates are presented.
On torsion anomalous intersections
Authors: Checcoli Sara , Veneziano Francesco , Viada Evelina
Published: March 2014

A deep conjecture on torsion anomalous varieties states that if

V

is a weak-transverse variety in an abelian variety, then the complement

V^{ta}

of all

V

-torsion anomalous varieties is open and dense in

V

. We prove some cases of this conjecture. We show that the

V

-torsion anomalous varieties of relative codimension one are non-dense in any weak-transverse variety

V

embedded in a product of elliptic curves with CM. We give explicit uniform bounds in the dependence on

V

. As an immediate consequence we prove the conjecture for

V

of codimension two in a product of CM elliptic curves. We also point out some implications on the effective Mordell-Lang Conjecture.
Existence and multiplicity results for anisotropic stationary Schrödinger equations
Authors: Afrouzi Ghasem A. , Mirzapour Maryam , Rădulescu Vicenţiu D.
Published: March 2014

In this paper we are concerned with a new class of quasilinear elliptic equations with a power-like reaction term and a di¤erential operator that involves partial derivatives with different powers. The functional-analytic framework relies on anisotropic Sobolev spaces. By means of combined variational arguments, we obtain the existence of weak solutions and, in case of symmetric settings, the existence of large or small energy solutions. In particular, we establish some results that extend the classical theory of combined e¤ects of concave and convex nonlinearities.
Importeurs en exporteurs van literatuur: de Nederlandse letteren in Frankrijk
Authors: Andringa Kim
Published: March 2014

French is an important target language in the translation of Dutch literary texts. This article offers a short qualitative and quantitative historical survey of Dutch language literary publications in French translation from 1900 to 2010. Throughout the twentieth century and the first decade of the twenty-first century, the quantity of translations has been increasing. Promotional activities by institutions such as the Nederlands Letterenfonds, formerly the NLPVF, contribute to making a peripheral literature known outside the boundaries of its linguistic area.

The article then goes on to investigate the essential, yet not very well-known, parts that various kinds of mediators play in the translation process, especially in transferring a given text from one national literary field to another. The theory of components as elaborated by Andringa, Levie & Sanders is used to categorise the particularly intricate web of relations between the literary fields of source language and target language in which these mediators, both individuals and institutions, intervene.

As actors behind the scenes, their role is difficult to grasp in reception studies, but they are decisive in their contextualisation, or ‘literarization’ (Casanova 1999), of Dutch literature aimed at a French audience.
Contrastieve fraseologie en corpora: een experiment met de zee / la mer
Authors: Colson Jean-Pierre
Published: March 2014

Phraseology, the study of all categories of set phrases, has now come to be seen as a major research field within linguistics. It also shows a clear relation„ship with many aspects of corpus linguistics and construction grammar. Some of the most interesting features of phraseology come from a contrastive perspective: the comparison between set phrases in two or more languages. While there is a general agreement that the phraseology of one particular language will be influenced by its culture and traditions, the precise methodology that should be used for contrastive phraseology remains uncertain. In this paper we report the results of an experiment designed to assess whether automated programs, applied to large linguistic corpora, will enable us to extract conclusive evidence for contrastive phraseology. The scope of the experiment is limited to phrases in combination with la mer (French) / de zee (Dutch). The results suggest that the recourse to automated tools is quite useful, while some aspects still have to be dealt with by traditional dictionary search. As far as the case study is concerned, sea phrases in Dutch and French appear to display fewer differences than might have been expected from the historical and cultural background of both languages.
Leve hun! Waarom hun nog steeds hun zeggen
Authors: van Bergen Geertje , Stoop Wessel , Vogels Jorrig , de Hoop Helen
Published: March 2014

More and more speakers of Dutch use the “object” personal pronoun hun as the subject of a sentence, although there is a strong social stigma attached to this use. In this article, we investigate what makes hun such a good subject in present-day Dutch. Basing the analysis on data from the Corpus of Spoken Dutch, we predict that the use of hun as a subject will remain alongside the use of zij and ze, because hun has the advantage of referring exclusively to animate entities such as humans, unlike the competing forms zij and ze.
De historische ontwikkeling van de tussenklank in Nederlandse nominale samenstellingen
Authors: van Tiel Bob , Rem Margit , Neijt Anneke
Published: March 2014

The distribution of linking elements in Dutch nominal compounds seems erratic at first glance. The literature attributes this to the origin of the linking elements as case markers. When the decay of the case system set in, these markers were retained in compounds but gradually lost their meaning. This allowed the case markers to spread to compounds with a paradigmatically incongruous first element and to acquire their new functions as plural ending and prosodic element. This sketch suggests that the decline of the case system was the main factor in the development of the linking elements. We argue against this view. The loss of case does not overtly correlate with the increase of linking elements. Furthermore, already in Middle-Dutch, the linking element had a prosodic function. The loss of case can only partly account for the spread of linking elements. We hypothesize that an equally important factor is the presence of head-initial stress, which also set in motion the decay of the case system. The erratic distribution of the linking elements is the result of an interplay between phonology, morphology and semantics.
Pragmatische partikels in de rechterperiferie
Authors: van der Wouden Ton , Foolen Ad
Published: March 2014

Compared with the left periphery, the right periphery of Dutch sentences and clauses has received little attention. This paper presents a study in which the positional possibilities of pragmatic markers as well as their contribution to the semantics and pragmatics of the sentence/utterance are explored. The value of different frameworks (generative, constructional and multifactorial) for the explanation of right periphery phenomena is discussed and the findings on Dutch final pragmatic markers are compared with similar phenomena in other languages.
Palatalisatie rond Amsterdam
Authors: van Bree Cor
Published: March 2014

The dialect of the city of Amsterdam is characterised by palatalisation (fronting) of short [α] and [o], especially before n, s, st and t. The consonants themselves are also palatalised and it may be that they trigger the palatalisation of the vowels. The palatalisation can also be heard well beyond the city borders. The precise input and conditions, the stylistic and regional aspects and the dimension of age were investigated by means of interviews in 94 towns and villages during the period 1986 – 2010. The results are as follows: 1. There is not much difference between [α] en [o]; as regards the conditions, the palatalisation decreases if we go from n via s and st to t. 2. It is a phenomenon which maintains itself very well (in any case there is no relevant difference between older and younger people); in the north of the province of North Holland (Westfriesland) the phenomenon is even expanding. 3. There is no clear difference as regards the formality of situation; hence it can be assumed that people are not very well aware of it. 4. Amsterdam is indeed the centre: on a map, one could draw circles indicating the degree of palatalisation, except that north of Amsterdam the image would be somewhat irregular, showing a weak palatalisation in Westfriesland, a stronger one north of this subregion and no palatalisation at all in the Zaan enclave northwest of Amsterdam. It is possible that the inhabitants of the Zaan region do not much like to resemble the inhabitants of Amsterdam. 5. About the historical background of this palatalisation nothing can be stated with certainty.
Ditransitieve constructies in het Nederlands: semasiologische en onomasiologische kwesties
Authors: Colleman Timothy
Published: March 2014

This paper presents a construction-based exploration of a number of formal and semantic issues surrounding the Dutch double object and prepositional dative constructions. The first part of the paper deals with the formal demarcation of these constructions vis-à-vis other three-place argument structure constructions. The second part discusses diachronic shifts and synchronic variation in the constructional semantics of the double object pattern, the third part briefly looks into the semantic relation between the double object construction and the prepositional dative. The overall aim of the paper is to give a general impression of the way such issues are dealt with in construction grammar.
Comparison of GEOS-5 AGCM planetary boundary layer depths computed with various definitions
Authors: McGrath-Spangler E. L. , Molod A.
Published: March 2014

Abstract. Accurate models of planetary boundary layer (PBL) processes are important for forecasting weather and climate. The present study compares seven methods of calculating PBL depth in the GEOS-5 atmospheric general circulation model (AGCM) over land. These methods depend on the eddy diffusion coefficients, bulk and local Richardson numbers, and the turbulent kinetic energy. The computed PBL depths are aggregated to the Köppen climate classes, and some limited comparisons are made using radiosonde profiles. Most methods produce similar midday PBL depths, although in the warm, moist climate classes, the bulk Richardson number method gives midday results that are lower than those given by the eddy diffusion coefficient methods. Additional analysis revealed that methods sensitive to turbulence driven by radiative cooling produce greater PBL depths, this effect being most significant during the evening transition. Nocturnal PBLs based on Richardson number are generally shallower than eddy diffusion coefficient based estimates. The bulk Richardson number estimate is recommended as the PBL height to inform the choice of the turbulent length scale, based on the similarity to other methods during the day, and the improved nighttime behavior.